Patent Application
20240395485
The present disclosure relates to magnetic couplers. More specifically, the present disclosure relates to variable field magnetic couplers including switchable magnetic couplers.
Magnetic couplers are known which are used to couple a ferromagnetic workpiece to transport the ferromagnetic workpiece from a first location to a second location, hold the ferromagnetic workpiece, and/or lift the ferromagnetic workpiece. An exemplary magnetic coupler is a switchable magnetic coupler which may include one or more permanent magnet(s) that is (are) rotatable relative to one or more stationary permanent magnet(s), in order to generate and shunt a magnetic field. The switchable magnet coupler may be attached in a removable manner, via switching the magnetic coupler between an “on” state and an “off” state, to a ferromagnetic workpiece, such as for object lifting operations, material handling, material holding, magnetically latching or coupling objects to one another, among other applications.
Embodiments of the present disclosure relate to magnetic couplers for holding, lifting, and/or transporting a ferromagnetic workpiece.
In an exemplary embodiment of the present disclosure, a magnetic coupling device for magnetically coupling to a ferromagnetic workpiece positioned on a support is provided. The magnetic coupling device comprising: a housing; a plurality of workpiece contact interfaces supported by the housing and adapted to contact the ferromagnetic workpiece; a first permanent magnet supported by the housing and having an active N-S pole pair; a second permanent magnet supported by the housing and having an active N-S pole pair, the second permanent magnet being moveable relative to the first permanent magnet; an actuator operatively coupled to the second permanent magnet to move the second permanent magnet relative to the first permanent magnet; and an electronic controller operatively coupled to the actuator. The electronic controller including logic which actuates the actuator to position the second permanent magnet relative to the first permanent magnet in at least each of: (a) a first state wherein the second permanent magnet has a first position relative to the first permanent magnet to provide a first level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the first level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces being insufficient to lift the ferromagnetic workpiece relative to the support; (b) a second state wherein the second permanent magnet has a second position relative to the first permanent magnet to provide a second level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the second level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces being sufficient to lift the ferromagnetic workpiece relative to the support, the second level of magnetic flux being greater than the first level of magnetic flux; and (c) a third state wherein the second permanent magnet has a third position relative to the first permanent magnet to provide a third level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the third level of magnetic flux being greater than each of the first level of magnetic flux and the second level of magnetic flux.
In an example thereof, the magnetic coupling device further comprises a sensing system supported by the housing. The sensing system including at least one sensor which monitors a level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces.
In a variation of the example thereof, thereof, the actuator is a stepper motor and the at least one sensor monitors the level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces by monitoring a position of an output of the stepper motor which controls a position of the second permanent magnet relative to the first permanent magnet.
In another variation of the example thereof, the magnetic coupling device further comprises a memory accessible by the electronic controller, wherein the actuator is a motor and the at least one sensor monitors a current draw of the motor, the electronic controller determines the level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces by monitoring the current draw of the motor and comparing the current draw to at least one stored reference value on the memory.
In another variation of the example thereof, the magnetic coupling device further comprises a memory accessible by the electronic controller, wherein a first sensor value of the at least one sensor is stored on the memory for at least one of the first state, the second state, and the third state. In a variation thereof, the first sensor value corresponds to the second state. In another variation thereof, the first sensor value corresponds to the first state, a second sensor value is stored on the memory which corresponds to the second state, and a third sensor value is stored on the memory which corresponds to the third state. In a further variation thereof, the electronic controller includes logic which actuates the actuator to position the second permanent magnet relative to the first permanent magnet in a fourth state wherein the second permanent magnet has a fourth position relative to the first permanent magnet to provide a fourth level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the fourth level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces being sufficient to lift the ferromagnetic workpiece relative to the support, the fourth level of magnetic flux being greater than the first level of magnetic flux, less than the third level of magnetic flux, and one of greater than and less than the second level of magnetic flux.
In still another variation of the example thereof, the at least one sensor monitors the level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces by monitoring a rotational position of the second permanent magnet.
In yet a further variation of the example thereof, the at least one sensor monitors the level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces by monitoring a first leakage magnetic flux associated with a first workpiece contact interface of the plurality of workpiece contact interfaces with a first magnetic flux sensor. In a variation thereof, the at least one sensor monitors the level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces by further monitoring a second leakage magnetic flux associated with a second workpiece contact interface of the plurality of workpiece contact interfaces with a second magnetic flux sensor. In a further variation thereof, the magnetic coupling device further comprises a memory accessible by the electronic controller, wherein a first sensor value of the first sensor is stored on the memory for at least one of the first state, the second state, and the third state. In still a further variation thereof, the first sensor value corresponds to the second state. In yet another variation thereof, the first sensor value corresponds to the first state, a second sensor value is stored on the memory which corresponds to the second state, and a third sensor value is stored on the memory which corresponds to the third state. In still another variation thereof, the electronic controller includes logic which actuates the actuator to position the second permanent magnet relative to the first permanent magnet in a fourth state wherein the second permanent magnet has a fourth position relative to the first permanent magnet to provide a fourth level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the fourth level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces being sufficient to lift the ferromagnetic workpiece relative to the support, the fourth level of magnetic flux being greater than the first level of magnetic flux, less than the third level of magnetic flux, and one of greater than and less than the second level of magnetic flux.
In still another variation of the example thereof, the actuator is a fluid actuator and the at least one sensor monitors the level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces by monitoring a fluid characteristic of a working fluid of the fluid actuator, the working fluid controls a position of the second permanent magnet relative to the first permanent magnet.
In still another variation of the example thereof, the actuator is a fluid actuator and the at least one sensor monitors a position of an output of the fluid actuator.
In another example thereof, the second permanent magnet is rotatable relative to the first permanent magnet about an axis intersecting with the second permanent magnet to alter a position of the second permanent magnet relative to the first permanent magnet.
In a further example thereof, the second permanent magnet is rotatable relative to the first permanent magnet about an axis in a non-intersecting relationship with the second permanent magnet to alter a position of the second permanent magnet relative to the first permanent magnet. In a variation thereof, the magnetic coupling device further comprises a first platter supported by the housing and a second platter supported by housing. The second platter being moveable relative to the first platter to alter a position of the second permanent magnet relative to the first permanent magnet. The first platter comprising a first plurality of spaced apart permanent magnets including the first permanent magnet, each of the first plurality of spaced apart permanent magnets has a north pole side and a south pole side, and a first plurality of pole portions interposed between adjacent permanent magnets of the first plurality of permanent magnets, wherein the first plurality of permanent magnets are arranged so that each pole portion of the first plurality of pole portions is one of a north pole portion which is adjacent the north pole side of two permanent magnets of the first plurality of permanent magnets and a south pole portion which is adjacent the south pole side of two permanent magnets of the first plurality of permanent magnets. The second platter comprising a second plurality of spaced apart permanent magnets including the second permanent magnet, each of the second plurality of spaced apart permanent magnets has a north pole side and a south pole side, and a second plurality of pole portions interposed between adjacent permanent magnets of the second plurality of permanent magnets, wherein the second plurality of permanent magnets are arranged so that each pole portion of the first plurality of pole portions is one of a north pole portion which is adjacent the north pole side of two permanent magnets of the second plurality of permanent magnets and a south pole portion which is adjacent the south pole side of two permanent magnets of the second plurality of permanent magnets.
In still another example thereof, the second permanent magnet is translatable relative to the first permanent magnet to alter a position of the second permanent magnet relative to the first permanent magnet.
In yet still another example thereof, at least one of the first state, the second state, and the third state is a partial on state of the magnetic coupling device.
In yet a further example thereof, at least two of the first state, the second state, and the third state are each a corresponding partial on state of the magnetic coupling device.
In still yet a further example thereof, each of the first state, the second state, and the third state are each a corresponding partial on state of the magnetic coupling device.
In a further still example thereof, the magnetic coupling device further comprises a plurality of removable pole shoes, each pole shoe supporting a respective one of the plurality of workpiece contact interfaces.
In another exemplary embodiment of the present disclosure, a magnetic coupling device for magnetically coupling to a ferromagnetic workpiece positioned on a support is provided. The magnetic coupling device comprising: a housing having a lower side; a plurality of workpiece contact interfaces supported by the housing and adapted to contact the ferromagnetic workpiece; a first permanent magnet supported by the housing and having an active N-S pole pair providing a generally constant level of magnetic flux; a coil positioned about the first permanent magnet; and an electronic controller including logic which controls a level of the current to be supplied to the coil to provide in at least each of: (a) a first state wherein a first level of current is provided to the coil, the coil and the first permanent magnet providing a first level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces based on the first level of current and the first permanent magnet, the first level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces being insufficient to lift the ferromagnetic workpiece relative to the support; (b) a second state wherein a second level of current is provided to the coil, the coil and the first permanent magnet providing a second level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces based on the second level of current and the first permanent magnet, the second level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces being sufficient to lift the ferromagnetic workpiece relative to the support, the second level of magnetic flux being greater than the first level of magnetic flux; and (c) a third state wherein a third level of current is provided to the coil, the coil and the first permanent magnet providing a third level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces based on the third level of current and the first permanent magnet, the third level of magnetic flux being greater than each of the first level of magnetic flux and the second level of magnetic flux.
In an example thereof, the magnetic coupling device further comprises a sensing system supported by the housing. The sensing system including at least one sensor which monitors a level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces. In a variation thereof, the at least one sensor is an electrical current sensor which monitors a level of current provided to the coil. In another variation thereof, the current passes through the coil in a first direction in the first state and in a second direction in the third state. In still another variation thereof, the third level of current is less than the second level of current.
In still another exemplary embodiment of the present disclosure, a magnetic coupling device for magnetically coupling to a ferromagnetic workpiece positioned on a support is provided. The magnetic coupling device comprising: a housing; a plurality of workpiece contact interfaces supported by the housing and adapted to contact the ferromagnetic workpiece; a first permanent magnet supported by the housing and having an active N-S pole pair; a second permanent magnet supported by the housing and having an active N-S pole pair, the second permanent magnet being moveable relative to the first permanent magnet; an actuator operatively coupled to the second permanent magnet to move the second permanent magnet relative to the first permanent magnet; an electronic controller operatively coupled to the actuator, the electronic controller including logic which actuates the actuator to position the second permanent magnet in a plurality of distinct orientations relative to the first permanent magnet; and a brake supported by the housing, the brake having an engaged state wherein the brake holds the second permanent magnet relative to the first permanent magnet and a disengaged state wherein the brake permits rotation of the second permanent magnet relative to the first permanent magnet.
In an example thereof, the electronic controller is operatively coupled to the brake, the logic of the electronic controller engaging the brake when the second permanent magnet is in one of the plurality of distinct orientations relative to the first permanent magnet. In a variation thereof, a first orientation of the second permanent magnet relative to the first permanent magnet corresponds to a first state of the magnetic coupling device to provide a first level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the first level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces being insufficient to lift the ferromagnetic workpiece relative to the support; a second orientation of the second permanent magnet relative to the first permanent magnet corresponds to a second state of the magnetic coupling device to provide a second level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the second level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces being sufficient to lift the ferromagnetic workpiece relative to the support, the second level of magnetic flux being greater than the first level of magnetic flux; and a third orientation of the second permanent magnet relative to the first permanent magnet corresponds to a third state of the magnetic coupling device to provide a third level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the third level of magnetic flux being greater than each of the first level of magnetic flux and the second level of magnetic flux.
In another still exemplary embodiment of the present disclosure, a lifting apparatus for lifting a ferromagnetic workpiece is provided. The lifting apparatus comprising a support structure; and a magnetic coupling device according any one of the embodiments, examples, variations, and refinements mentioned herein operatively coupled to the support structure.
In an example thereof, the support structure includes a robotic arm having a plurality of moveable arm segments and the magnetic coupling device is coupled to an end of the robotic arm.
In another example thereof, the support structure includes a mechanical gantry, the magnetic coupling device being suspended from the mechanical gantry.
In still another example thereof, the support structure includes a crane hoist, the magnetic coupling device being suspended from the crane hoist.
In a further exemplary embodiment of the present disclosure, a fixture for holding a ferromagnetic workpiece is provided. The fixture comprising a frame and at least one magnetic coupling device positioned to support a lower side of the ferromagnetic workpiece. Each magnetic coupling device comprising a housing having a first side; a plurality of workpiece contact interfaces supported by the housing and adapted to contact the ferromagnetic workpiece; a first permanent magnet supported by the housing and having an active N-S pole pair; a second permanent magnet supported by the housing and having an active N-S pole pair, the second permanent magnet being moveable relative to the first permanent magnet; an actuator operatively coupled to the second permanent magnet to move the second permanent magnet relative to the first permanent magnet; and an electronic controller operatively coupled to the actuator. The electronic controller including logic which actuates the actuator to position the second permanent magnet relative to the first permanent magnet in at least each of: (a) a first state wherein the second permanent magnet has a first position relative to the first permanent magnet to provide a first level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the first level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces being insufficient to hold the ferromagnetic workpiece relative to the magnetic coupling device; and (b) a second state wherein the second permanent magnet has a second position relative to the first permanent magnet to provide a second level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the second level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces being sufficient to hold the ferromagnetic workpiece relative to the magnetic coupling device, the second level of magnetic flux being greater than the first level of magnetic flux.
In an example thereof, the at least one magnetic coupling device includes a plurality of magnetic coupling devices, each of the plurality of magnetic coupling devices has associated pole shoes with workpiece contact interfaces shaped to match a corresponding profile of the ferromagnetic workpiece. In a variation thereof, the plurality of magnetic coupling devices are spaced apart.
In still a further exemplary embodiment of the present disclosure, a method of moving a ferromagnetic workpiece positioned on a support with a magnetic coupling device. The method comprising the steps of: contacting the ferromagnetic workpiece with a plurality workpiece contact interfaces of the magnetic coupling device, the magnetic coupling device having at least one permanent magnet which contributes to a level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces; transitioning the magnetic coupling device from a first state having a first level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces to a second state having a second level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the second level being greater than the first level; moving the ferromagnetic workpiece relative to the support with the magnetic coupling device from a first position to a second position while the magnetic coupling device is in the second state; transitioning the magnetic coupling device from the second state to a third state having a third level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the third level being greater than the second level; moving the ferromagnetic workpiece with the magnetic coupling device from the second position to a third position while the magnetic coupling device is in the third state; and decoupling the ferromagnetic workpiece from the magnetic coupling device.
In yet still a further exemplary embodiment of the present disclosure, a method of moving a ferromagnetic workpiece positioned on a support with a magnetic coupling device is provided. The method comprising the steps of: receiving an identification of ferromagnetic workpiece to be moved with a magnetic coupling device having a plurality of workpiece contact interfaces adapted to contact the ferromagnetic workpiece, the magnetic coupling device having at least one permanent magnet which contributes to a level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces; determining at least one state of the magnetic coupling device that corresponds to the identified ferromagnetic workpiece, the at least one state having a corresponding level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces of the magnetic coupling device; contacting the identified ferromagnetic workpiece with the workpiece contact interfaces of the magnetic coupling device; moving the identified ferromagnetic workpiece relative to the support with the magnetic coupling device from an initial position to a final position while sequentially configuring the magnetic coupling device in at least three states, each of the three states having a corresponding level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces of the magnetic coupling device, the at least three states including the at least one state of the magnetic coupling device that corresponds to the identified ferromagnetic workpiece; and decoupling the identified ferromagnetic workpiece from the magnetic coupling device.
Other aspects and optional and/or preferred embodiments will become apparent from the following description provided below with reference to the accompanying drawings.
While the disclosed subject matter is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the disclosure to the particular embodiments described. On the contrary, the disclosure is intended to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.
Embodiments provided herein relate to switchable magnetic devices. Exemplary switchable magnetic devices are disclosed in U.S. Pat. No. 7,012,495, titled SWITCHABLE PERMANENT MAGNETIC DEVICE; U.S. Pat. No. 7,161,451, titled MODULAR PERMANENT MAGNET CHUCK; U.S. Pat. No. 8,878,639, titled MAGNET ARRAYS, U.S. Provisional Patent Application No. 62/248,804, filed Oct. 30, 2015, titled MAGNETIC COUPLING DEVICE WITH A ROTARY ACTUATION SYSTEM, docket MTI-0007-01-US-E; German Utility Model DE202016006696U1; U.S. Provisional Patent Application No. 62/252,435, filed Nov. 7, 2015, titled MAGNETIC COUPLING DEVICE WITH A LINEAR ACTUATION SYSTEM, docket MTI-0006-01-US-E; and U.S. patent application Ser. No. 15/964,884, filed Apr. 27, 2018, titled MAGNETIC COUPLING DEVICE WITH AT LEAST ONE OF A SENSOR ARRANGEMENT AND A DEGAUSS CAPABILITY, docket MTI-0013-02-US, the entire disclosures of which are expressly incorporated by reference herein.
The illustrated examples herein in
Further, exemplary switchable magnetic devices may include a first plurality of permanent magnets movable relative to a second plurality of permanent magnets. An example is provided in
Additionally, exemplary switchable magnetic devices may include at least a first permanent magnet positioned within a first housing which acts as a pole extension of the at least a first permanent magnet, the first housing being movable relative to a second housing having at least a second permanent magnet positioned within the second housing, the second housing acts as a pole extension of the at least a second permanent magnet.
Referring to
Although each of permanent magnet 12 and permanent magnet 14 are shown as single magnets, switchable magnet device may include multiple permanent magnets which provide the functionality of permanent magnet 12 and multiple permanent magnets which provide the functionality of permanent magnet 14. Additionally, permanent magnet 12 (or multiple magnets providing the functionality of permanent magnet 12) and permanent magnet 14 (or multiple magnets providing the functionality of permanent magnet 14) may be positioned within respective housings that act as pole extensions for the respective magnets. Further, in embodiments, permanent magnets 12, 14 may include more than two poles. Examples including quadpole magnets and other magnets having more than two poles.
Pole shoes 16′, 16″ are illustratively shown being removably coupled to housing 28. In embodiments, pole shoes 16′, 16″ are integrally formed as part of housing 28. Pole shoes 16′, 16″ are made of a ferromagnetic material and are magnetically coupled to permanent magnets 12, 14 through portions of housing 28. A lower portion of each of pole shoes 16′, 16″ include a workpiece contact interface 17′, 17″ which may be brought into contact with a workpiece 27, illustratively a top sheet 27′ of ferromagnetic material of a stack of sheets 27′, 27″, and 27″ of the ferromagnetic material. The stack of sheets 27 is supported by a support, such as a floor, a frame, or other exemplary supports. Further, lower sheets 27 in the stack support the top sheet 27 in the stack.
Workpiece contact interfaces 17′, 17″ of pole shoes 16′, 16″ cooperate with magnets 12, 14 through pole shoes 16′, 16″ and housing 28 to form first and second poles of the magnets 12, 14. In one example, a single unitary pole shoe forms each of the pole shoes 16′, 16″. In another example, a plurality of pole shoes form each of the pole shoes 16′, 16″. Additional pole shoe arrangements are disclosed in U.S. Provisional Patent Application No. 62/623,407, filed Jan. 29, 2018, titled MAGNETIC LIFTING DEVICE HAVING POLE SHOES WITH SPACED APART PROJECTIONS, docket MTI-0015-01-US, the entire disclosure of which is expressly incorporated by reference herein. Pole shoes 16′, 16″ extend beyond a lower surface of housing 28 to provide an air gap 60 between housing 28 and workpiece 27.
In embodiments, permanent magnet 14 is fixed relative to housing 28 and permanent magnet 12 is movable within housing 28 relative to permanent magnet 14 in order to alter an alignment of the magnet portions 18, 20 of the permanent magnet 12 relative to the magnet portions 22, 24 of permanent magnet 14. In the illustrated embodiment, permanent magnet 12 is rotatable relative to permanent magnet 14. Although permanent magnets 12, 14 are shown being vertically stacked with permanent magnet 12 rotatable about vertical axis 55, in other embodiments, permanent magnets 12, 14 are vertically stacked and permanent magnet 12 is rotatable about a horizontal axis. Additional layouts of permanent magnets 12, 14 are contemplated.
Switchable magnetic coupling device 10 based on the configuration of permanent magnets 12, 14 establishes multiple magnetic circuits. In particular, switchable magnetic device 10 may be configured in at least three states, each of which has a corresponding magnetic circuit characteristic. Switchable magnetic device 10 is capable to maintain the configurations of permanent magnets 12, 14 in each of the at least three states for an extended period of time, as explained in more detail herein. In one example, the current state of magnetic coupling device 10 is maintained until a different state is requested.
In a first state referred to herein as an off state, permanent magnet 12 has a first position relative to permanent magnet 14 to provide a first level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces 17′, 17″ of the pole shoes 16′, 16″. In the off state, the first level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces 17′, 17″ of the pole shoes 16′, 16″ is insufficient to lift the ferromagnetic workpiece with the magnetic coupling device 10.
Referring to
In the off state, the majority of the magnetic flux of permanent magnets 12, 14 remains in housing 28 as part of a first magnetic circuit between permanent magnets 12, 14 and is not available at the workpiece contact interfaces 17, 17′ of pole shoes 16′, 16″ to pass through ferromagnetic workpiece 27 as shown in
In a second state referred to herein as an on state, permanent magnet 12 has a second position relative to the permanent magnet 14 to provide a second level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces 17′, 17″ of the pole shoes 16′, 16″. In the on state, the second level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces 17′, 17″ of the pole shoes 16′, 16″ is higher than the first level of the off state and is sufficient to lift the ferromagnetic workpiece with the magnetic coupling device 10.
Referring to
In the on state, the majority of the magnetic flux of permanent magnets 12, 14 is available at the workpiece contact interfaces 17′, 17″ of pole shoes 16′, 16″ to pass through ferromagnetic workpiece 27 as shown in
In a third state referred to herein as a partial on state, permanent magnet 12 has a third position relative to the permanent magnet 14 to provide a third level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces 17′, 17″ of the pole shoes 16′, 16″. In the partially on state, the third level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces 17′, 17″ of the pole shoes 16′, 16″ is higher than the first level of the off state, is lower than the second level of the on state, and is sufficient to lift the ferromagnetic workpiece with the magnetic coupling device 10. In embodiments, magnetic coupling device 10 may be placed in multiple partial on states.
Referring to
In each of the partial on states, a portion of the magnetic flux of permanent magnets 12, 14 is available at the workpiece contact interfaces 17′, 17″ of pole shoes 16′, 16″ to pass through ferromagnetic workpiece 27 as shown in
As explained in more detail herein, by being able to position and maintain magnetic switching device 10 in at least three states, the ability of configuring magnetic coupling device 10 for destacking ferromagnetic workpieces arranged in a stack is enhanced and the ability to use magnetic coupling device 10 for multiple different types of ferromagnetic workpieces is enhanced.
By way of example, in the on state shown in
Once raised in direction 33, magnetic coupling device 10 may be configured in the on state or an additional partial on state having a level of magnetic flux available to the workpiece contact interfaces 17′, 17″ of pole shoes 16′,16″ between the previously disclosed partial on state of
Returning to
Exemplary engagement portions and actuators are disclosed in U.S. Pat. No. 7,012,495, titled SWITCHABLE PERMANENT MAGNETIC DEVICE; U.S. Pat. No. 7,161,451, titled MODULAR PERMANENT MAGNET CHUCK; U.S. Pat. No. 8,878,639, titled MAGNET ARRAYS, U.S. Provisional Patent Application No. 62/248,804, filed Oct. 30, 2015, titled MAGNETIC COUPLING DEVICE WITH A ROTARY ACTUATION SYSTEM, docket MTI-0007-01-US-E; German Utility Model DE202016006696U1; U.S. Provisional Patent Application No. 62/252,435, filed Nov. 7, 2015, titled MAGNETIC COUPLING DEVICE WITH A LINEAR ACTUATION SYSTEM, docket MTI-0006-01-US-E; and U.S. patent application Ser. No. 15/964,884, filed Apr. 27, 2018, titled MAGNETIC COUPLING DEVICE WITH AT LEAST ONE OF A SENSOR ARRANGEMENT AND A DEGAUSS CAPABILITY, docket MTI-0013-02-US, the entire disclosures of which are herein expressly incorporated by reference.
In embodiments, actuator 32 may be an electric motor, a pneumatic drive system, a hydraulic drive system, or other suitable systems for reorienting permanent magnet 12 relative to permanent magnet 14. In embodiments, actuator 32 is coupled to controller 34 which controls the operation of the respective actuator 32 and hence the alignment of permanent magnet 12 relative to permanent magnet 14 through engagement portion 30. In embodiments, controller 34 is an electronic controller which controls the operation of the respective actuator 32.
As illustrated in
In embodiments, electronic controller 34 changes the state of magnetic coupling device 10 in response to an input signal received from an input device 42. Exemplary input devices include switches, buttons, touch screens, microphones, detectors, controllers, and other devices whereby an operator may provide one of a tactile, audio, or visual input command For example, in one embodiment, magnetic coupling device 10 is coupled to an end of arm of a robotic arm and input device 42 is a network interface over which controller 34 receives instructions from a robot controller on when to place magnetic coupling device 10 in one of the plurality of states of magnetic coupling device 10. Exemplary network interfaces include a wired network connection and a wireless network connection including one or more of an antenna, an optical receiver or transceiver, or other suitable wireless communication receivers or transceivers. While the embodiments discussed herein relate to electronic, pneumatic, or hydraulic actuation, in alternative embodiments, a version of the magnetic coupling device is provided without electronic controller 34 and is actuated manually. Exemplary manual actuators include handles, knobs, and other devices actuatable by a human operator. By contrast, electronic controller 34 of magnetic coupling device 10 is able to control actuator 32 automatically without human intervention. Thus, electronic controller 34 may execute logic which places magnetic device 10 in a series of states automatically based on parameters of the logic, at least one of the states being a partial on state. In embodiments, the functionality of magnetic coupling device state logic 40 is executed by controller 770 of robot system 700 or other remote processing device.
Magnetic coupling device 10 further includes one or more output devices 44. Exemplary output devices include visual output devices and audio output devices. Exemplary visual output devices include lights, display screens, and other types of visual indicators or communication devices. Exemplary audio output devices include speakers and other types of audio indicator devices.
Referring to
In another example, a stepper motor is provided. The stepper motor may be operated in open loop assuming it has sufficient drive torque to actuate the unit without losing steps. A sensor may be provided to assist in establishing the angular position of the output, such as a shaft or aperture to receive a shaft, of the stepper motor and hence the position of permanent magnet 12. For example, first sensor 61 counts the pulses used to drive the stepper motor and determines the angular position of the shaft of the stepper motor based on the number of pulses. Permanent magnet 12 is moved relative to permanent magnet 14 to a defined position by the steps the motor moves by counting the number of pulses. In another example, a stepper motor is provided that integrates an encoder with the stepper to check that the proper actuation angle is maintained.
An exemplary pneumatic rotary actuator is a semi rotary actuator with a rotary vane, or a semi-rotary actuator driven by linear pneumatic pistons coupled to a central output shaft by rack and pinon.
Referring to
Controller 34 is coupled to a pressure/exhaust system 376 which is in fluid communication with A port 366 through a fluid line 378 and to a pressure/exhaust system 380 which is in fluid communication with B port 370 through a fluid line 382. In embodiments, pressure/exhaust system 376 and pressure/exhaust system 380 are a single system. Each of pressure/exhaust system 376 and pressure/exhaust system 380 may either supply the working fluid to the respective A port 366 and B port 370 or exhaust the working fluid from the respective A port 366 and B port 370.
Controller 34, through pressure/exhaust system 376 and pressure/exhaust system 380 establishes a desired pressure on each side of paddle 364 to hold paddle 364 at an intermediate position, such as for a desired partial on state, between the first limit position and the second limit position of paddle 364. In embodiments, controller 34 stores in memory 38 a desired fluid characteristic of the working fluid, such as pressure or other suitable fluid characteristics, corresponding to various desired intermediate positions. Further, controller 34 monitors the fluid characteristics, such as pressures or other suitable fluid characteristics, associated with both sides of paddle 364 through sensors 386, 388. In embodiments, controller 34 further monitors another fluid characteristic of the working fluid, the flow of the working fluid through fluid lines 368, 372. In embodiments, fluid actuator 360, instead of and/or in addition to monitoring a fluid characteristic of the working fluid, monitors a rotary position of output 374 of the fluid actuator 362. For example, in embodiments, output 374 is an output shaft and a sensor 384, illustratively a rotary encoder sensor system, is used to monitor a rotational position of the output shaft. In one example, wherein fluid actuator 362 is a hydraulic actuator, a volume of flow of the working fluid is monitored by controller 34. In another example, wherein fluid actuator 362 is a pneumatic actuator, the rotary position of output 374 of the fluid actuator 362 is monitored by controller 34.
In another embodiment, first sensor 61 is a current sensor which monitors a current draw of electric motor 58. Based on the position of permanent magnet 12 relative to permanent magnet 14, the amount of current drawn by electric motor 58 changes due to changes in the required torque to move permanent magnet 12 relative to permanent magnet 14. By measuring motor current drawn by motor 58 as a function of the position of permanent magnet 12, the rotation position of permanent magnet 12 may be inferred by comparison to a table of values stored on memory 38 or a function stored on memory 38. In one example, the table of values includes rows of the position of permanent magnet 12 relative to permanent magnet 14 and the corresponding current draw of motor 58 when the workpiece interfaces 17′, 17″ of magnetic coupling device 10 are contacting workpiece 27. The corresponding current draw values are experimentally determined by measuring the current draw of motor 58 for various positions of permanent magnet 12 relative to permanent magnet 14 when the workpiece interfaces 17′, 17″ of magnetic coupling device 10 are contacting workpiece 27.
Further, the positioning of the magnetic coupling device 10 in close proximity with ferromagnetic workpiece 27 alters the current required to move permanent magnet 12. Thus, a controlled actuation of the motor 58 over a range of motion as magnetic coupling device 10 approaches workpiece 27 may be used to determine a proximity of magnetic coupling device 10 to workpiece 27.
For example, as magnetic coupling device 10 approaches workpiece 27 motor 58 may be periodically actuated to move permanent magnet 12 relative to permanent magnet 14 from a first known position, such as the off position, to a second known position, such as a known partial on position, and subsequently returned to the first known position. The current draw to accomplish the actuation to move permanent magnet 12 relative to permanent magnet 14 from the first known position to the second known position may be compared to a table of values stored on memory 38 to infer proximity of the magnetic coupling device 10 to the workpiece 27. The table of values may include rows of the measured proximity of the workpiece interfaces 17′, 17″ of magnetic coupling device 10 relative to workpiece 27 and the corresponding measured current drawn by motor 58 for the actuation to move permanent magnet 12 relative to permanent magnet 14 from the first known position to the second known position at the measured proximity of the workpiece interfaces 17′, 17″ of magnetic coupling device 10 relative to workpiece 27.
Additionally, the coupling of multiple workpieces to magnetic coupling device 10 alters the current required to move permanent magnet 12 relative to permanent magnet 14 compared to the coupling of a single workpiece. Thus, by experimentally determining the current draw required to complete a controlled actuation of the motor 58 over a range of motion, a determination may be made whether the magnetic coupling device 10 is coupled to a single workpiece 27 or multiple workpieces.
Referring to
Referring to
As mentioned herein switchable magnetic coupling device 10 is capable to maintain the configurations of permanent magnets 12, 14 in each of the at least three states for an extended period of time, as explained in more detail herein. In one example, the current state of magnetic coupling device 10 is maintained until a different state is requested. In embodiments, actuator 32 is a stepper motor and the ability of the stepper motor to hold its output shaft at a current position also holds permanent magnet 12 at a current position and hence magnetic coupling device 10 in a current state.
Referring to
As shown in
As shown in
Referring to
In embodiments, magnetic coupling device 10 includes a brake, such as a frictional brake which may interact with a rotatable member coupled to permanent magnet 12. The frictional brake may be applied to maintain the current position of rotatable member and hence the current position of permanent magnet 12. In embodiments, controller 34 actuates the brake to hold the current position of permanent magnet 12 if power is interrupted to magnetic coupling device 10. In another embodiment, the brake is normally applied to hold the current position of permanent magnet 12 and is actuated to permit the movement of permanent magnet 12.
Referring to
In embodiments, magnetic coupling device 10 has an elongated housing to hold multiple instances of magnetic flux source 15 in a linear array. An exemplary device having multiple instances of magnetic flux source 15 is the LAY Series unit as manufactured and sold by Magswitch Technology Inc. Referring to
Further, magnetic coupling device 400 includes magnetic field sensors 198 positioned within housing 402. Magnetic field sensors 198 are shown being positioned proximate the pole shoes 404 of two of the magnetic flux sources 15, illustratively flux sources 15A and 15C. In embodiments, magnetic field sensors 198 are associated with only a single flux source 15 of the plurality of magnetic flux sources 15A-C. In embodiments, magnetic field sensors 198 are associated with each flux source 15 of the plurality of magnetic flux sources 15A-C. Controller 34 by monitoring the magnetic field sensors 198 is able to determine the operating state (on state, off state, or one of a partial on state) of the monitored magnetic flux sources 15. Other sensing system disclosed herein may be used in place of magnetic field sensors 198 or in addition to magnetic field sensors 198.
In embodiments, magnetic coupling device 10 has an elongated housing to hold multiple instances of magnetic flux source 15 in a circular array. An exemplary device having multiple instances of magnetic flux source 15 is the AY Series unit as manufactured and sold by Magswitch Technology Inc. Referring to
Further, magnetic coupling device 450 includes magnetic field sensors 198 positioned within housing 452. In embodiments, magnetic field sensors 198 are positioned in cylindrical protrusions 458 extending down from a lower surface 460 of housing 452. In the illustrated embodiment, two magnetic sensors 198 are positioned in respective protrusions 458, one being positioned between magnetic flux source 15F and 15A and the other positioned between magnetic flux sources 15C and 15D. In embodiments, a magnetic field sensor 198 is positioned in a protrusion 458 between any two of magnetic flux sources. In embodiments, magnetic field sensors 198 are positioned in respective protrusions between each pair of adjacent magnetic flux sources 15A-F along a diameter of the circular array. Controller 34 by monitoring the magnetic field sensors 198 is able to determine the operating state (on state, off state, or one of a partial on state) of the monitored magnetic flux sources 15. Other sensing system disclosed herein may be used in place of magnetic field sensors 198 or in addition to magnetic field sensors 198.
Referring to
Two identical ferromagnetic pole shoes 138 of essentially rectangular prismatic configuration (but for chamfered edges at an outside face), of a material magnetically compatible with or the same as housing 122, are mounted to the width-ward sides at the lower portion of housing 122 to complement the shape of the upper portion of housing 122, using bolts 140 and locator pins 142. Pole shoes 138 define at a lower face respective work piece contact interfaces 144 which in the illustrated embodiment are planar, but could be of different geometry and/or contoured to form fittingly abut against a target surface of a work piece to be magnetically coupled to and handled by magnetic coupling device 100. As noted, the pole shoes 138 define at their lower terminal end the workpiece contact interfaces 144, whereas the top faces of the thick-walled width-ward portions of housing 122 define what will herein be termed flux detection surfaces 146. In absence of an external magnetic working circuit, and even when such is created, magnetic flux lines pass through both the workpiece contact interfaces 144 and flux detection surfaces 146 of housing 122.
Actuator and electronic sensor and feedback assembly 118 includes a lower rectangular-footprint actuator housing part 150 made from a non-ferromagnetic material, such as aluminium, and includes a rectangular depression 152 with a through passage opening towards the lower face of housing part 150, which serves to house a rotary actuator 154. Rotary actuator 154 has a torque output shaft 156 which in the assembled state of magnetic coupling device 100, in which lower housing part 150 is hermetically secured to the top of the magnet assembly's housing 122 using four fastening bolts 158 which extend through four bores in lower housing part 150 and engage with threaded bores on the top face of housing 122, is inserted into an engagement member, illustratively a hexagonal drive insert 136, present at the upper magnet 132. This enables actuator 154 to impart selective torque to rotate top magnet 132 in its housing 122 to turn the switchable permanent magnet device 120 between various states. Exemplary rotary actuators include hydraulic actuators, pneumatic actuators, and electrical actuators, as mentioned herein. The lines across the upper faces of both magnets 130, 132 represent the respective separation planes of the North and South active poles of magnets 130, 132.
An intermediate aluminium (or other non-ferromagnetic metallic) housing part 166 of housing assembly 118 has a rectangular footprint and is secured to the lower housing part 150 by the above mentioned fastening bolts 158. On top of intermediate housing part 166 is a rectangular frame-like upper housing part 172, also made from non-ferromagnetic metal material, whose upper open end is closed by a rectangular non-ferromagnetic cover plate 174 which by way of four fastening screws 176 extending through bores at the four corners of upper housing part 172 is sandwiched in sealing manner between cover plate 174 and intermediate housing part 166.
Assembly 118 further includes a magnetic field sensor and sensor signal processing circuit unit 190 including two leg portions 196 which at their respective terminal ends each carry a magnetic flux sensor 198 of Linear Hall Effect type. Processing circuit unit 190 includes an M12 electronic connector 192 for interfacing I/O signals to/from the sensors and microcontroller with external equipment. Other suitable connectors may be used based on the connection to be established.
Leg portions 196 of processing circuit unit 190 extend into the two cylindrical passage channels 170 in lower housing part 150 when upper housing assembly 118 is assembled. The overall arrangement ensures that the Hall Effect sensors 198 will be securely located in a defined position a small distance away from the flux detection surfaces 146 of housing 122. In essence, this arrangement ensures that one magnetic flux sensor 198 is positioned over a first one of the pole shoes 138 and a second magnetic flux sensor 198 is positioned over a second one of the pole shoes 138. Additional details of magnetic coupling device 100 are disclosed in U.S. Provisional Application No. 62/490,705, the entire disclosure of which is expressly incorporated by reference herein.
As mentioned herein other configurations of magnets may be used in place of permanent magnets 12, 14 or permanent magnets 130, 132. Referring to
Switchable magnetic coupling device 200 includes an upper platter 212 and a lower platter 214. Each of platters 212 and 214 include a plurality of spaced-apart permanent magnets 230 and a plurality of pole portions 250. Each of the plurality of spaced-apart permanent magnets 230 are illustratively shown as a single permanent magnet, but may comprise multiple permanent magnets and/or at least one permanent magnet positioned within a housing. Exemplary platters are provided in U.S. Pat. No. 7,161,451; U.S. Provisional Patent Application No. 62/248,804, filed Oct. 30, 2015, titled MAGNETIC COUPLING DEVICE WITH A ROTARY ACTUATION SYSTEM, docket MTI-0007-01-US-E; and German Utility Model DE202016006696U1, the entire disclosures of which are expressly incorporated by reference herein.
Returning to the example of
Each of upper platter 212 and lower platter 214 includes an equal and even number of permanent magnet sections and an equal number of pole portions 250. In one embodiment, in each of upper platter 212 and lower platter 214, permanent magnets 230 and pole portions 250 are arranged in a circular configuration.
In embodiments, lower platter 214, like magnet 14 in magnetic coupling device 10, is held stationary relative to the housing containing lower platter 214 and upper platter 212, like magnet 12 in magnetic coupling device 10, rotates relative to lower platter 214. Upper platter 212 is rotatable in directions 290, 292 about a central axis 294 relative to lower platter 214 to alter an alignment of the permanent magnets 230 and pole portions 250 of upper platter 212 relative to the permanent magnets 230 and pole portions 250 of lower platter 214.
Magnetic coupling device 200 is considered to be in an on state when the south pole portions 250 of lower platter 214 are aligned with the south pole portions 250 of upper platter 212 and the north pole portions 250 of lower platter 214 are aligned with the north pole portions 250 of upper platter 212. In the on-state, workpiece 27 is held by magnetic coupling device 10 due to a completion of a magnetic circuit from the aligned north pole portions 250 of upper platter 212 and lower platter 214, through the workpiece 27, and to the aligned south pole portions 250 of upper platter 212 and 214.
Magnetic coupling device 200 is considered to be in an off state when the south pole portions 250 of lower platter 214 are aligned with the north pole portions 250 of upper platter 212 and the north pole portions 250 of lower platter 214 are aligned with the south pole portions 250 of upper platter 212. In the off state, a workpiece 27 is not held by magnetic coupling device 10 due to a completion of a magnetic circuit within upper platter 212 and lower platter 214 from the aligned north pole portions 250 of upper platter 212 to the south pole portions 250 of lower platter 214 and from the aligned north pole portions of upper platter 212 to the south pole portions 250 of lower platter 214.
Magnetic coupling device 200 is considered to be in a partial on state when the south pole portions 250 of upper platter 212 are partially overlapping the north pole portions 250 of lower platter 214 and the north pole portions 250 of upper platter 212 are partially overlapping the south pole portions 250 of lower platter 214. When in the partial on state, a workpiece 27 may be held by magnetic coupling device 10 due to a completion of a magnetic circuit from the overlapping north pole portions 250 of upper platter 212 and lower platter 214, through the workpiece 27, and to the overlapping south pole portions 250 of upper platter 212 and lower platter 214. The strength of the magnetic circuit increases as the degree of overlap of the overlapping north pole portions 250 of upper platter 212 and lower platter 214 and the overlapping south pole portions 250 of upper platter 212 and lower platter 214 increases.
Referring to
Referring to
As shown in
Referring to
Referring to
Referring to
In embodiments, at least one of the north pole portions 250 and at least one of the south pole portions 250 has a magnetic flux sensor 198 associated therewith to monitor the leakage flux associated with the respective north pole portion and the respective south pole portion. As shown in
Referring to
Each permanent magnet 330 has a north pole side (N) and a south pole side(S). The permanent magnets 330 and pole portions 350 of assembly 312 and of assembly 314 are each arranged in a linear array wherein one of pole portions 350 is positioned between two of permanent magnets 330. Further, the permanent magnets 330 are arranged so that each of the two permanent magnets 330 contacting the pole portion 350 therebetween have either their north pole sides (N) or their south pole sides(S) contacting the pole portion 350. When the north pole sides (N) of the adjacent permanent magnets 330 are contacting a pole portion 350, the pole portion 350 is referred to as a north pole portion. When the south pole sides(S) of the adjacent permanent magnets 330 are contacting a pole portion 350, the pole portion 350 is referred to as a south pole portion.
In embodiments, lower assembly 314, like permanent magnet 14 in magnetic coupling device 10 or permanent magnet 130 in magnetic coupling device 100 is held stationary relative to the housing containing lower assembly 314 and upper assembly 312, like permanent magnet 12 of magnetic coupling device 10 or permanent magnet 132 of magnetic coupling device 100, rotates relative to lower assembly 314. Upper assembly 312 is translatable relative to lower assembly 314 in directions 390 and 392 to alter an alignment of the permanent magnets 330 and pole portions 350 of upper assembly 312 relative to the permanent magnets 330 and pole portions 350 of lower assembly 314. Permanent magnets 330 of lower assembly 312 are spaced apart from workpiece 27 due to pole shoes 340 coupled to pole portions 350. Alternatively, pole portions may be extended to provide the spacing. Additionally, a spacer (not shown) is provided between the permanent magnets of upper assembly 312 and lower assembly 314.
Magnetic coupling device 300 is considered to be in an on state when the south pole portions 350 of lower assembly 314 are aligned with the south pole portions 350 of upper assembly 312 and the north pole portions 350 of lower assembly 314 are aligned with the north pole portions 350 of upper assembly 312 (see
Magnetic coupling device 300 is considered to be in an off state when the south pole portions 350 of lower assembly 314 are aligned with the north pole portions 350 of upper assembly 312 and the north pole portions 350 of lower assembly 314 are aligned with the south pole portions 350 of upper assembly 312 (see
Magnetic coupling device 300 is considered to be in a partial on state when the south pole portions 350 of upper assembly 312 are partially overlapping the north pole portions 350 of lower assembly 314 and the north pole portions 350 of upper assembly 312 are partially overlapping the south pole portions 350 of lower assembly 314. When in the partial on state, a workpiece 27 may be held by magnetic coupling device 10 due to a completion of a magnetic circuit from the overlapping north pole portions 350 of upper assembly 312 and lower assembly 314, through the workpiece 27, and to the overlapping south pole portions 350 of upper assembly 312 and lower assembly 314. The strength of the magnetic circuit increases as the degree of overlap of the overlapping north pole portions 350 of upper assembly 312 and lower assembly 314 and the overlapping south pole portions 350 of upper assembly 312 and lower assembly 314 increases.
In embodiments, at least one of the north pole portions 350 and at least one of the south pole portions 350 has a magnetic flux sensor 198 associated therewith to monitor the leakage flux associated with the respective north pole portion and the respective south pole portion. As shown in
Referring to
A permanent magnet 420 having a north pole 422 and a south pole 424 is positioned in central cavity 410. Permanent magnet 420 providing a generally constant level of magnetic flux. Since central section 404 is made of a ferromagnetic material, sections 406, 408 of housing 402 act as pole extensions of south pole portion 424 and north pole portion 422, respectively. Permanent magnet 420 is fixed in housing 402 to not rotate relative to housing 402. Fixing the orientation of permanent magnet 420 within housing 402 may be achieved by selecting the respective diameters of cavity 410 and magnet 420 to provide a press or tight interference fit, or by gluing permanent magnet 420 in cavity 410 or suitable methods of holding permanent magnet 420 relative to housing 402.
A coil 450 including one or more windings of electrically insulated wire is wound around the central section 412 of housing 402. Ends 406, 408 of housing 402 act as containment walls in between which coil 450 is wound. Coil 450 comprises, for example, a single coil of copper wire which is wound around wall sections 412 of central section 404, in effect covering central cavity 410 of housing 402 and permanent magnet 420 received therein.
Coil 450 is operatively coupled to an electrical power source through a connection 460. Exemplary connections include switches or circuitry which controls a level of current supplied to coil 450. As shown in
Magnetic coupling device 400 based on the properties of permanent magnet 420 and the properties of an electrical current level and an electrical current direction passing through coil 450 may establish multiple magnetic circuits. In particular, magnetic coupling device 400 may be configured in at least three states, each of which has a corresponding magnetic circuit characteristic. Magnetic coupling device 400 is capable of maintaining each of the at least three states for an extended period of time by maintaining an effectively constant current level through coil 450 or no current through coil 450. In one example, the extended period of time is up to 120 seconds. In another example, the extended period of time is up to 10 seconds. In a further example, the extended period of time is up to 5 seconds. In yet another example, the extended period of time is up to 2 seconds. In still another example, the extended period of time is up to 1 second. In yet a further example, the above exemplary ranges have a minimal duration set based on system requirements, such as of at least 0.1 seconds.
In embodiments, a temperature sensor is included to monitor a temperature of coil 450. In one example, magnetic coupling device 400 is operated as long as the measured temperature is below a threshold temperature. An exemplary threshold temperature is 80° Celsius.
In a first state referred to herein as an off state, a first current level is passed through coil 450 to effectively mitigate or cancel the magnetic flux of permanent magnet 420 to provide a first level of magnetic flux available to the ferromagnetic workpiece 27 at the workpiece contact interfaces 17′, 17″ of the pole shoes 16′, 16″. In the off state, the first level of magnetic flux available to the ferromagnetic workpiece 27 at the workpiece contact interfaces 17′, 17″ of the pole shoes 16′, 16″ is insufficient to lift the ferromagnetic workpiece with the magnetic coupling device 420. In one example, at least 96% percent of the magnetic flux produced by permanent magnet 420 is cancelled by coil 450 when magnetic coupling device 400 is in the off state. In another example, at least 99% of the magnetic flux produced by permanent magnet 420 is cancelled by coil 450 when magnetic coupling device 400 is in the off state.
In a second state referred to herein as an on state, a second current level is passed through coil 450 to provide a second level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces 17′, 17″ of the pole shoes 16′, 16″. In one example, no current is passed through coil 450 such that the full amount of magnetic flux produced by permanent magnet 420 is available to the ferromagnetic workpiece 27 at the workpiece contact interfaces 17′, 17″ of the pole shoes 16′, 16″. In the on state, the second level of magnetic flux available to the ferromagnetic workpiece 27 at the workpiece contact interfaces 17′, 17″ of the pole shoes 16′, 16″ is higher than the first level of the off state and is sufficient to lift the ferromagnetic workpiece with the magnetic coupling device 400. In one example, the magnetic flux produced by permanent magnet 420 alone is sufficient to lift the ferromagnetic workpiece. Thus, if power is inadvertently cut to coil 450, magnetic coupling device 400 retains the ferromagnetic workpiece 27 coupled to magnetic coupling device 400.
In a third state referred to herein as a partial on state, a third current level is passed through coil 450 to provide a third level of magnetic flux available to the ferromagnetic workpiece 27 at the workpiece contact interfaces 17′, 17″ of the pole shoes 16′, 16″. The third current level cancels out at least a part of the magnetic flux available at the workpiece contact interfaces 17′, 17″ of the pole shoes 16′, 16″ from the permanent magnet 420. In the partial on state, the third level of magnetic flux available to the ferromagnetic workpiece 27 at the workpiece contact interfaces 17′, 17″ of the pole shoes 16′, 16″ is higher than the first level of the off state, is lower than the second level of the on state, and is sufficient to lift the ferromagnetic workpiece with the magnetic coupling device 400. In one example, the partial on state is sufficient to lift top sheet 27′ of stack 27, but not both top sheet 27′ and second from the top sheet 27″.
In embodiments, a sensor 462 is provided to monitor a characteristic of coil 450. In one example, sensor 462 is a current sensor which monitors a current level passing through coil 450 or supplied to coil 450.
As explained in more detail herein, by being able to configure magnetic coupling device 400 in at least three states, the ability of configuring magnetic coupling device 400 for destacking ferromagnetic workpieces 27 arranged in a stack is enhanced and the ability to use magnetic coupling device 400 for multiple different types of ferromagnetic workpieces 27 is enhanced. Additional details regarding an exemplary magnetic coupling device 400 are disclosed in U.S. Provisional Application Ser. No. 62/517,043, filed Jun. 8, 2017, titled SWITCHABLE MAGNETIC APPARATUS, docket MTI-0004-02-US, the entire disclosure of which is expressly incorporated by reference herein.
In embodiments, a coil 450 is wrapped around both of permanent magnets 12, 14 of magnetic coupling device 10 and is used to further increase the magnetic flux available at workpiece contact interfaces 17′, 17″ of pole shoes 16′, 16″ over the on state. In embodiments, coil 450 is wrapped around permanent magnet 14 of magnetic coupling device 10 to cancel or reduce the effective magnetic flux of permanent magnet 14 acting on permanent magnet 12 to lower the torque needed to rotate permanent magnet 12 relative to permanent magnet 14.
In embodiments, instead of being fixed in housing 402, permanent magnet 420 is rotatable in housing 402. An actuation system 470 is operatively coupled to permanent magnet 420 to rotate permanent magnet 420 relative to housing 402. In one embodiment, actuation system may be an electrical actuation system, such as a stepper motor, a hydraulic actuation system, a pneumatic actuation system, or other suitable actuation systems. In one embodiment, permanent magnet 420 is rotated relative to housing 402 through current applied to one or more coils positioned about permanent magnet 420. Additional details of exemplary coil actuation systems are provided in U.S. Provisional Application No. 62/517,057, titled ELECTROMAGNET-SWITCHABLE PERMANENT MAGNET DEVICE, filed Jun. 8, 2017, docket MTI-0001-02-US, the entire disclosure of which is expressly incorporated by reference herein.
Referring to
Referring to
Referring to
Each of the disclosed magnetic coupling devices may be used in combination with mechanical lifting apparatus 430 (See
Exemplary mechanical gantries 432 include a pair of vertical support members having a horizontal cross member extending therebetween. Magnetic coupling device 10 may be suspended from or coupled to the horizontal cross member through a mechanism to raise and lower magnetic coupling device 10 relative to the horizontal cross member and hence to lift and transport a ferromagnetic workpiece coupled to magnetic coupling device 10.
Exemplary crane hoists 434 include a chain mechanism that raises or lowers a first portion of chain hoist 434 relative to a second portion of chain hoist 434. Magnetic coupling device 10 may be suspended from or coupled to the first portion of chain hoist 434. Hence, magnetic coupling device 10 is raised and lowered with the first portion of chain hoist 434 which in turn lifts and transports a ferromagnetic workpiece coupled to magnetic coupling device 10.
Referring to
Robotic system 700 includes electronic controller 770. Electronic controller 770 includes additional logic stored in associated memory 774 for execution by processor 772. A robotic movement module 702 is included which controls the movements of a robotic arm 704. In the illustrated embodiment, robotic arm 704 includes a first arm segment 706 which is rotatable relative to a base about a vertical axis. First arm segment 706 is moveably coupled to a second arm segment 708 through a first joint 710 whereat second arm segment 708 may be rotated relative to first arm segment 706 in a first direction. Second arm segment 708 is moveably coupled to a third arm segment 711 through a second joint 712 whereat third arm segment 711 may be rotated relative to second arm segment 708 in a second direction. Third arm segment 711 is moveably coupled to a fourth arm segment 714 through a third joint 716 whereat fourth arm segment 714 may be rotated relative to third arm segment 711 in a third direction and a rotary joint 718 whereby an orientation of fourth arm segment 714 relative to third arm segment 711 may be altered. Magnetic coupling device 10 is illustratively shown secured to the end of robotic arm 704. Magnetic coupling device 10 is used to couple a workpiece 27 (not shown) to robotic arm 704. Although magnetic coupling device 10 is illustrated, any of the magnetic coupling devices described herein and any number of the magnetic coupling devices described herein may be used with robotic system 700.
In one embodiment, electronic controller 770 by processor 772 executing robotic movement module 702 moves robotic arm 704 to a first pose whereat magnetic coupling device 100 contacts the workpiece at a first location. Electronic controller 770 by processor 772 executing a magnetic coupler state module 776 instructs magnetic device 10 to move upper magnet 12 relative to lower magnet 14 to place magnetic coupling device 10 in one of the on state or a partial on state to couple the workpiece to robotic system 700. Electronic controller 770 by processor 772 executing robotic movement module 702 moves the workpiece from the first location to a second, desired, spaced apart location. Once the workpiece is at the desired second position, electronic controller 770 by processor 772 executing magnetic coupler state module 76 instructs magnetic device 10 to move upper magnet 12 relative to lower magnet 14 to place magnetic coupling device 10 in the off state to decouple the workpiece from robotic system 700. In one example, electronic controller 770 by processor 772 executing magnetic coupler state module 76 instructs magnetic coupling device 10 to sequentially place the magnetic coupling device 10 in the partially on state to lift a ferromagnetic workpiece 27′, after lifting the ferromagnetic workpiece 27′ by moving robotic arm 704 instructs magnetic coupling device 10 to move upper magnet 12 relative to lower magnet 14 to place magnetic coupling device 10 in the on state or another partial on state to increase the holding force of magnetic coupling device 10 on ferromagnetic workpiece 27′, and after positioning the ferromagnetic workpiece 27′ in a desired location by further moving the robotic arm 704 instructs magnetic coupling device 10 to move upper magnet 12 relative to lower magnet 14 to place magnetic coupling device 10 in the off state to decouple ferromagnetic workpiece 27′ from robotic system 700. Electronic controller 770 then repeats the process to couple, move, and decouple another workpiece 27.
Referring to
Referring to
Magnetic coupling device state logic 40 may select the appropriate data record based on a requested state of the magnetic coupling device 10, 100, 200, 300 or 400 requested by input device 42. As mentioned herein, in embodiments, magnetic coupling devices 10, 100, 200, 300 or 400 may be coupled to a robotic arm 704 of a robotic system 700 and electronic controller 770 of robotic system 700 may request a desired state of magnetic coupling device 10, 100, 200, 300 or 400 based on a position of robotic arm 704 by providing the state identifier 82 of the desired state to controller 34 of magnetic coupling device 10, 100, 200, 300 or 400.
In practice, an operator of magnetic coupling device 10, 100, 200, 300 or 400 may position magnetic coupling device 10, 100, 200, 300 or 400 on a stack of ferromagnetic workpieces, such as sheets 27. The operator may through input device 42 manually request actuation of actuator 32 to rotate permanent magnet 12 to a partial on position or similar movement for magnetic coupling devices 100, 200, or 300. Through experimentation or through monitoring sensor readings, the operator will continue to alter a position of permanent magnet 12 until a position is reached that provides sufficient lifting force to raise the top sheet 27′ in direction 33, but not raise the second from the top sheet 27″ in direction 33. The sensor values associated with this orientation of permanent magnet 12 are stored in a data record 80 as corresponding to a partial on state identifier 82. Then, when working with sheets 27, robotic system 700 is able to specify the correct state identifier 82 for the partial on data record. In a similar manner, the current in coil 450 may be monitored and recorded for system 400.
The sensor values for a plurality of partial on states may be stored in corresponding data records 80 on memory 38. In one example, data records 80 are stored for each state for which the magnetic coupling device is to be configured.
In embodiments, robotic system 700 or magnetic coupling device 10 includes a workpiece data record 86 that correlates a given workpiece identifier 88 with a given state identifier 82, as illustrated in
In embodiments, between steps 510 and 512, the magnetic coupling device is transitioned from the third state to a fourth state having a fourth level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the fourth level being less than the third level, but still sufficient to hold the workpiece relative to the magnetic coupling device. In one example, the fourth level is used when the workpiece is approaching a second stack of workpieces that the workpiece is to be placed on top of the stack. By reducing the level of magnetic flux, the chance that a workpiece already on the stack is moved due to the magnetic flux of the magnetic coupling device. In another example, the workpiece is being placed in a nesting relationship relative to a second workpiece and once the second workpiece is in place, the magnetic flux level is increased so that both workpieces are coupled to the magnetic coupling device with sufficient magnetic flux to move the multiple workpieces.
In embodiments, the second level of magnetic flux in the second stack is sufficient to couple multiple workpieces in a stack of workpieces to the magnetic coupling device. Once the multiple workpieces are coupled, the multiple workpieces are moved to a second position. At this point the magnetic flux level may be increased to strengthen the level of connection with magnetic coupling device. In one example, the magnetic coupling device moves the multiple workpieces to a first drop location and the level of magnetic flux is lowered to release a bottom one of the multiple workpieces. This is repeated at different locations until all of the multiple workpieces are released.
In embodiments, a magnetic coupling device having at least three states is an electro-permanent magnetic coupling device including at least one first permanent magnet, at least one second permanent magnet, and an electrical coil placed around the at least one second permanent magnet. The at least one first permanent magnet is/are a high coercivity magnet and the at least one second permanent magnet is/are a low coercivity magnet whose magnet poles may be changed due to the influence of an electrical current supplied to the electrical coil placed around the at least one second permanent magnet. An exemplary high coercivity magnet is an NdFeB (Neodymium, Iron, Boron) magnet. An exemplary low coercivity magnet is an AlNiCo (Aluminium, Nickel, Cobalt) magnet.
The at least one first permanent magnet, the at least one second permanent magnet, and the electrical coil are contained in a housing having associated pole shoes with workpiece contact interfaces. The orientation of the magnetic poles of the at least one second permanent magnet may have a first orientation wherein a first level of magnetic flux is available to the workpiece contact interfaces of the pole shoes, the first level being sufficient to lift ferromagnetic workpiece 27. Further, the orientation of the magnetic poles of the at least one second permanent magnet may have a second orientation wherein a second level of magnetic flux is available to the workpiece contact interfaces of the pole shoes, the second level being insufficient to lift ferromagnetic workpiece 27. When in the first orientation a first current level may be applied to coils that reduces the magnetic flux available at the workpiece contact interfaces of the pole shoes to a third level less than the first level and greater than the second level. The third level corresponding to a partial on state. In one example, the third level is sufficient to destack ferromagnetic workpiece 27′ from the remainder of ferromagnetic workpieces. The first current level being insufficient to alter the magnetic poles of the at least one second permanent magnet to the second orientation. When in the second orientation a second current may be applied to coils that increases the magnetic flux available at the workpiece contact interfaces of the pole shoes to a fourth level less than the first level and greater than the second level. The fourth level corresponding to a partial on state. In one example, the fourth level is sufficient to destack ferromagnetic workpiece 27′ from the remainder of ferromagnetic workpieces. The second current level being insufficient to alter the magnetic poles of the at least one second permanent magnet to the first orientation.
Referring to
Ferromagnetic workpiece 490 may be inspected with one or more probes 488 that contact an upper side 494 of ferromagnetic workpiece 490. In embodiments, the electronic controller 34 of each magnetic coupling device 10 orients the magnets of the magnet coupling devices 10 to provide a level of magnetic flux available at the workpiece contact interfaces 17 of the pole shoes 16 to hold the ferromagnetic workpiece 490 relative to fixture 486, but low enough to not alter the operation of the probe inspecting the upper side 494 of ferromagnetic workpiece 490.
In embodiments, each of the plurality of magnetic coupling devices 10 has associated pole shoes 16 with workpiece contact interfaces 17 shaped to match a corresponding profile of the lower side 492 of ferromagnetic workpiece 490. In embodiments, the plurality of magnetic coupling devices 10 are spaced apart.
Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.
This application is a continuation of U.S. patent application Ser. No. 17/130,868, filed Dec. 22, 2020, titled VARIABLE FIELD MAGNETIC COUPLERS AND METHODS FOR ENGAGING A FERROMAGNETIC WORKPIECE, which is a continuation of U.S. patent application Ser. No. 15/965,582 (now U.S. Pat. No. 10,903,030), filed Apr. 27, 2018, titled VARIABLE FIELD MAGNETIC COUPLERS AND METHODS FOR ENGAGING A FERROMAGNETIC WORKPIECE, which claims the benefit of U.S. Provisional Patent Application No. 62/634,783, filed Feb. 23, 2018, titled VARIABLE FIELD MAGNETIC COUPLERS AND METHODS FOR ENGAGING A FERROMAGNETIC WORKPIECE, docket MTI-0016-01-US and to U.S. Provisional Patent Application No. 62/490,705, filed Apr. 27, 2017, titled MAGNETIC COUPLING TOOL WITH SENSOR ARRANGEMENT, the entire disclosures of which are expressly incorporated by reference herein. U.S. patent application Ser. No. 15/964,884, filed Apr. 27, 2018, titled MAGNETIC COUPLING DEVICE WITH AT LEAST ONE OF A SENSOR ARRANGEMENT AND A DEGAUSS CAPABILITY, docket MTI-0013-02-US, is expressly incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 62634783 | Feb 2018 | US | |
| 62490705 | Apr 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17130868 | Dec 2020 | US |
| Child | 18435705 | US | |
| Parent | 15965582 | Apr 2018 | US |
| Child | 17130868 | US |
