The present disclosure relates to linear actuators, and in particular to rotatable linear actuators.
There are several applications where it would be desirable to rotate a linear actuator, particularly in manufacturing and quality control applications. However, rotating a linear actuator requires complex designs to accommodate the rotating parts. In situations where only small rotations are desired, such as less than 180 degree rotations, wiring to the actuator components can generally be designed to accommodate such rotation. However, if a larger degree of rotation is desired the wiring can generally not be designed to accommodate such rotation, let alone if a 360 degree rotation is performed or if multiple 360 degree rotations are performed.
As one example, gripping devices are used in manufacturing and quality control applications to grab an object and move the object from one location to another as well as to hold the object for inspection. To grab the object, a gripping unit of the gripping device is linearly actuated. To move the object and to facilitate inspection of the object, it would be beneficial to rotate the object while being held by the gripper unit. Further, in particular for smaller objects such as vials or syringes, during the manufacturing process the ability to move and reposition the objects along the assembly line requires accuracy and precision to avoid damage while maintaining efficiency. The overall size of the gripper and associated control hardware can limit the flexibility of the assembly line configuration and processing efficiency. It would be beneficial to have a rotatable linear actuator that could be incorporated into such gripping devices without requiring a complex design, and while also providing accuracy and precision of the actuation.
Accordingly, an additional, alternative, and/or improved rotatable linear actuator remains highly desirable.
Features and advantages of the present disclosure will become apparent from the following detailed description, taken in combination with the appended drawings, in which:
It will be noted that throughout the appended drawings, like features are identified by like reference numerals.
In accordance with one aspect of the present disclosure, a rotatable linear actuator is disclosed, comprising: an actuator body; a drive shaft arranged within the actuator body, the drive shaft having a longitudinal axis and configured to be linearly actuated along and rotatable around the longitudinal axis within the actuator body, wherein the drive shaft is configured to be coupled at a first end thereof to a linearly actuated component that is configured to receive linear and rotational movement; one or more permanent magnets coupled to the drive shaft and magnetized in a radial direction about the longitudinal axis; and one or more electric coils disposed within the actuator body around the one or more permanent magnets and configured to receive an electric current that interacts with a magnetic field of the one or more permanent magnets to generate an axial force to linearly actuate the drive shaft.
In some aspects, the rotatable linear actuator further comprises an electric motor disposed within the actuator body and configured to rotate a rotationally actuated component. The rotationally actuated component may also be the linearly actuated component or be coupled to the linearly actuated component.
In some aspects, the one or more permanent magnets are coupled to the drive shaft at a second end thereof.
In some aspects, the rotatable linear actuator comprises two permanent magnets and two corresponding electric coils each disposed around a respective of the two permanent magnets, wherein the two permanent magnets have opposite polarity.
In some aspects, the rotatable linear actuator further comprises a magnetically-permeable material disposed between the drive shaft and the one or more permanent magnets.
In some aspects, the rotatable linear actuator further comprises a bobbin arranged in the actuator body around the one or more permanent magnets, and wherein the one or more electric coils are wound around the bobbin.
In some aspects, the rotatable linear actuator further comprises a magnetically-permeable coil housing within which the one or more electric coils are disposed.
In some aspects, the one or more electric coils are disposed around the one or more permanent magnets and extend along the longitudinal axis of the drive shaft according to an actuation amount of the drive shaft.
In some aspects, the rotatable linear actuator further comprises a wireless transceiver configured to receive wireless instructions to control the rotatable linear actuator.
In some aspects, the rotatable linear actuator further comprises a sensor configured to measure a position of the drive shaft.
In accordance with another aspect of the present disclosure a gripping device is disclosed, comprising the rotatable linear actuator of any one of the above aspects, and a gripping unit that is configured to be rotated and to be actuated between open and closed positions by the drive shaft to grip an object.
In some aspects, the gripping unit comprises a hub that is the linearly actuated component coupled to the drive shaft, and two or more gripper jaws coupled to the hub and that actuate between the open and closed positions when the hub is linearly actuated by the drive shaft.
In some aspects, the hub comprises angled slots, and wherein the two or more gripper jaws are each coupled to a roller disposed within a respective angled slot, wherein linear actuation of the hub causes movement of the roller within the respective angled slot and actuation of the corresponding gripper jaw.
In some aspects, the two or more gripper jaws are pivotally coupled to a gripper housing, and wherein the gripper housing is the rotationally actuated component rotatable by the electric motor.
In some aspects, the two or more gripper jaws are coupled to a linear rail perpendicular to the longitudinal axis of the drive shaft.
In another aspect of the present disclosure, a conveying system is disclosed, comprising the gripping device of any one of the above aspects.
In another aspect of the present disclosure, a method of transferring an object between first and second gripping devices is disclosed, the first and second gripping devices each corresponding to the gripping device of any one of the above aspects, and the method comprising: gripping a first portion of the object with the gripping unit of the first gripping device; positioning the second gripping device at a second portion of the object; actuating the gripping unit of the second gripping device to grip the second portion of the object; and actuating the gripping unit of the first gripping device to release the first portion of the object.
In some aspects, positioning the second gripping device at the second portion of the object comprises moving the first gripping device and the second gripping device towards each other at a constant speed.
In some aspects, positioning the second gripping device at the second portion of the object comprises rotating at least one of the first and second gripping devices to a predetermined orientation.
In some aspects, the method further comprises rotating at least one of the first and second gripping devices while the gripping unit is being actuated.
The present disclosure provides a rotatable linear actuator where linear motion of a drive shaft is achieved using a magnet and coil assembly, thus allowing the drive shaft to be rotatable while also being linearly actuated. The use of the magnet and coil assembly to drive the drive shaft provides for a simplified device and compact design as components of the actuator driving the drive shaft in the linear direction do not have to rotate.
As discussed above, there are several applications where it would be beneficial to rotate a linear actuator, and the rotatable linear actuator in accordance with the present disclosure can be scaled up or down and used in any application requiring both linear actuation and rotation of one or more actuated components. The rotatable linear actuator may provide particular benefits when used in applications where an element is being rotated more than 180 degrees, for example, and even further benefits in applications where the element is being rotated 360 degrees more than once, where a wired connection cannot be designed to accommodate the rotation.
Accordingly, although the present disclosure describes the rotatable linear actuator with reference to a particular implementation where the rotatable linear actuator is used in a gripping device as part of a manufacturing/quality control application, it will be appreciated that the rotatable linear actuator can be used in any application requiring both linear actuation and rotation of an actuated component.
Embodiments are described below, by way of example only, with reference to
As seen in
In certain implementations, one or more cameras (not shown) may be arranged at different locations along the conveying system 100 to image the object 106 held by the rotatable linear actuator 104 for inspection. For example, the camera may be used to inspect a cap of the object, crimping or cracks in the object, and/or the substance inside the object. In some applications, the object may contain a liquid and the camera may be used to inspect for any particulates in the liquid. As would be appreciated, to facilitate inspection of the object, it would be desirable to rotate the object 106 while it is held by the gripping device 104. As described in more detail with reference to
In this particular implementation, the support unit 102 may provide power to the gripping device 104. In some examples, the support unit 102 may provide inductive power to the gripping device 104, and the support unit comprises inductive power pickup 202, where power is delivered to the gripping devices by inductive power coils along the track to the rear of the support unit 102. The gripping device 104 may comprise or be coupled to a microcontroller (not shown) that is configured to control power to different components of the gripping device. The gripping device 104 and particularly the rotatable linear actuator may also comprise a wireless transceiver configured to receive commands from a central controller allowing communication to one or more gripping devices.
The support unit 102 is one example of how the gripping device 104 may be mounted to a conveying system, however as described with reference to
The gripping unit 302 comprises at least one actuated gripper jaw that is configured to be actuated to grab and release an object. While different configurations of gripping units are possible, the gripping unit 302 as shown comprises two actuated gripper jaws 304a and 304b, which comprise hinged gripper fingers 305a and 305b configured to grip the object, although more actuated gripper jaws may be utilized. The gripper jaws 304a and 304b may be pivotally arranged on a gripper housing 308, which is configured to be rotated. Bearings (not seen in
Actuation of the gripping unit 302 between the open and closed configurations is achieved by actuation of a drive shaft 322 that is coupled to the slotted hub 306 of the gripping unit 302 at a first end thereof. The drive shaft 322 is configured to be linearly actuated within housing 324 of the rotatable linear actuator 320 to actuate the gripper jaws 304a and 304b of the gripping unit 302 between the open and closed configurations. In the configuration shown in
Referring to
While the connection between the gripper jaws 304a and 304b, the slotted hub 306, and the drive shaft 322 provides a particularly compact design, a person skilled in the art will also appreciate that other configurations are possible to cause the gripper jaws to open and close, and that such designs may be implemented without departing from the scope of this disclosure. Further, various actuated components could be used instead of gripping unit 302, and therefore the particular connection with which the drive shaft 322 causes actuation of the linearly actuated component can vary.
Linear movement of the drive shaft 322 within the actuator body 324 is advantageously achieved using a magnet and coil assembly. As best seen in
One or more electric coils 330 are disposed within the actuator body around the one or more permanent magnets. The electric coils 330 are configured to receive an electric current that interacts with a magnetic field of the one or more permanent magnets to generate an axial force to linearly actuate the drive shaft 322. In this example, there are two sets of permanent magnets 326a and 326b, and there are two corresponding electric coils 330a and 330b disposed around the permanent magnets. The two electric coils 330a and 330b are wound in opposite directions since the polarity of the magnets 326a and 326b are opposite each other. Alternatively, instead of having two electric coils 330a and 330b, a single continuous electric coil 330 may be used, wound clockwise around one set of permanent magnets and counter-clockwise around the other set of permanent magnets. The electric coil 330 or electric coils 330a and 330b are configured so that they extend along an axial direction in a range of movement of the magnets 326a and 326b on the drive shaft 322.
The electric coils 330a and 330b are disposed within the actuator body 324 of the rotatable linear actuator 320, and more specifically within a magnetically-permeable coil housing 332. The electric coils 330a and 330b may be wrapped around a plastic bobbin 334, which holds the electric coils 330a and 330b in place. A spring 344 (see
Note that in an alternative configuration, one magnet or set of magnets having the same polarity could be used with one electric coil. The space where the second magnet is shown in
Referring again to
Various types of encoders or sensors could be used to provide positional feedback on the drive shaft 322, magnets 326, motor 340, etc. As one example, a laser or optical sensor may be used at the end of the drive shaft 322 to determine its position.
While
As described above, different components, including different gripping units, may be coupled to and actuated by the rotatable linear actuator 320. In the alternative gripping device 104′, instead of gripper jaws 304a and 304b that are pivotally coupled to the gripper housing 308, gripping unit 402 comprises gripper jaws 404a and 404b that are actuated along respective linear rails in a direction towards and away from each other. With two gripper jaws 402a and 402b, the gripper jaws are actuated in opposite directions parallel to each other. However, it would also be appreciated that a different number of gripper jaws may be present, such as four gripper jaws. The linear rails are arranged along a gripping surface of the gripping unit 402 (i.e. perpendicular to the longitudinal axis of the drive shaft 322).
As seen in
More specifically, referring to
An amount of movement of the gripper jaws 404a and 404b may be set by an angle and length of the angled slots 412. Again, other shapes of angled slots 412 are also possible. While the connection between the gripper jaws 404a and 404b, the slotted hub 406, and the drive shaft 322 provides a particularly compact design, a person skilled in the art will also appreciate that other configurations are possible to cause the gripper jaws to open and close, and that such designs may be implemented without departing from the scope of this disclosure.
There may be situations where it is desirable to hand-off objects from one gripping device 104 on one track of the conveying system 600 to another gripping device 104 on another track of the conveying system 600. For example, as described with reference to
In accordance with the handoff of the object 106 between gripping devices 104, the gripping device 104 are actuated at certain times for grip/release the object to facilitate the handoff. As also described, the gripping device 104 may be rotated before, during, and/or after the handoff. Accordingly, the rotatable linear actuator disclosed herein which permits linear actuation of the drive shaft while being rotated is particularly suited for performing the gripper-to-gripper handoff of an object between gripping devices.
The method 700 comprises gripping a first portion of a object with a first gripping device (702). A second gripping device is positioned at a second portion of the object (704). For example, positioning the gripping device at the second portion of the object may comprise moving the first gripping device and the second gripping device towards each other at a constant speed. Further, positioning the second gripping device at the second portion of the object may comprise rotating at least one of the first and second gripping devices to a predetermined orientation.
The gripping unit of the second gripping device is actuated to grip the second portion of the object (706), and the gripping unit of the first gripping device is actuated to release the first portion of the object (708). When one or both of the first and second gripping devices are being actuated to grip/release the object, they may also be rotated. The operation of the object transferring procedure can occur by a controller operating the movement and actuation of the associated grippers. Sensors may be provided for determining location and operation state of the gripper process. Alternatively the actuation of the gripper may be performed based upon timed or position based triggers.
It would be appreciated by one of ordinary skill in the art that the system and components shown in the figures may include components not shown in the drawings. For simplicity and clarity of the illustration, elements in the figures are not necessarily to scale, are only schematic and are non-limiting of the elements structures. It will be apparent to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as described herein.
This application claims priority to U.S. Provisional Patent Application No. 63/407,025, filed on Sep. 15, 2022, the entire contents of which is incorporated by reference herein for all purposes.
Number | Date | Country | |
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63407025 | Sep 2022 | US |