Patent Application
20240246791
This disclosure relates to a device that feeds an elongated workpiece to a forming machine, a retrofit kit that retrofits a basic device designed to feed an elongated workpiece to a forming machine, a forming installation with such a forming machine, and a method of operating an aforementioned device.
Forming machines are machine tools that, with the aid of suitable tools, can produce smaller or larger series of shaped parts with partly complex geometry predominantly by forming from elongated workpieces such as wire, tube, strip or the like in an automatic production process. The forming machine may be, for example, a bending machine that produces two-dimensionally or three-dimensionally bent parts from wire material, strip material or tube material by bending, a straightening machine that straightens workpieces, a nailing machine or a spring-producing machine that produces compression springs, tension springs, leg springs or other spring-like shaped parts by spring winding or spring coiling. Highly productive computer-numerically controlled forming machines with numerous machine axes, which are controlled in a coordinated manner by a control device, are used today to efficiently produce large quantities of shaped parts.
During the production of shaped parts, the workpiece material is drawn in or conveyed from a workpiece supply to the tool area of the forming machine under the control of an NC control program by a drawing-in device of the forming machine. The fed wire is formed into the desired shaped part by the forming tools downstream in the material conveying direction. Before or after the shaping forming, the workpiece portion intended for producing the shaped part is separated from the fed workpiece material under the control of the NC control program by a cutting device. That process is cyclically repeated for each shaped part.
For devices of the type considered here, the workpiece supply is provided in the form of a coil. The term “coil” refers here to a package of the workpiece material wound up in the manner of a coil. A wound-up workpiece supply intended for processing is accommodated in a reeling unit before the beginning of productive operation. A reeling unit of the type considered here has a reel mounted rotatably about a reel axis and can carry the workpiece material in a wound-up form. The reeling unit is part of a device assigned to the forming machine to feed the elongated workpiece to the forming machine.
For reliable, trouble-free operation of such a device and the forming machine equipped with it, it is important to avoid as far as possible adverse effects of the workpiece feed on the operation of the forming machine and ensure that the reel runs as smoothly as possible when the workpiece material is gradually dispensed.
It could therefore be helpful to provide a device that feeds an elongated workpiece to a forming machine, a retrofit kit that retrofits a basic device, a forming installation with a forming machine comprising such a device and a method of operating such a device that allows particularly reliable, trouble-free operation.
I provide a device that feeds an elongated workpiece to a forming machine that has a drawing-in device that draws in the fed workpiece and conveys the workpiece to a tool area of the forming machine, including a reeling unit with a frame and a reel carried by the frame and accommodates a workpiece supply formed as a coil of workpiece material, the reel being mounted rotatably about a reel axis relative to the frame, wherein the device has a weight-distribution sensing device set up to sense and determine a lateral distribution of a reel weight with respect to the reel axis, the reel weight representing a weight of the reel with or without an accommodated coil.
I also provide a retrofit kit that retrofits a basic device designed to feed an elongated workpiece to a forming machine, the basic device having a reeling unit with a frame and a reel carried by the frame and accommodates a workpiece supply formed as a coil of workpiece material, the reel being mounted rotatably about a reel axis relative to the frame, the retrofit kit having components of a weight-distribution sensing device set up to sense a lateral distribution of a reel weight with respect to the reel axis, the reel weight representing a weight of the reel with or without an accommodated coil.
I further provide a forming installation with a forming machine having a drawing-in device that can be operated with a varying drawing-in speed and draws in an elongated workpiece and conveys the workpiece to a tool area of the forming machine, the forming installation including the device that feeds an elongated workpiece to a forming machine that has a drawing-in device that draws in the fed workpiece and conveys the workpiece to a tool area of the forming machine, including a reeling unit with a frame and a reel carried by the frame and accommodates a workpiece supply formed as a coil of workpiece material, the reel being mounted rotatably about a reel axis relative to the frame, wherein the device has a weight-distribution sensing device set up to sense and determine a lateral distribution of a reel weight with respect to the reel axis, the reel weight representing a weight of the reel with or without an accommodated coil, and the device is set up to feed an elongated workpiece to the forming machine.
I also further provide a method of operating the device that feeds an elongated workpiece to a forming machine that has a drawing-in device that draws in the fed workpiece and conveys the workpiece to a tool area of the forming machine, including a reeling unit with a frame and a reel carried by the frame and accommodates a workpiece supply formed as a coil of workpiece material, the reel being mounted rotatably about a reel axis relative to the frame, wherein the device has a weight-distribution sensing device set up to sense and determine a lateral distribution of a reel weight with respect to the reel axis, the reel weight representing a weight of the reel with or without an accommodated coil, including:
My devices are used to feed an elongated workpiece to a forming machine. The forming machine has a drawing-in device that draws in the fed workpiece and conveys the workpiece to a tool area of the forming machine. The device that feeds is also referred to for short as the “feeding device”.
The device comprises a reeling unit with a frame and with a reel carried by the frame. The reel is set up to accommodate a workpiece supply in the form of a coil of workpiece material. The reel is mounted rotatably about a reel axis relative to the frame. Preferably, the reel axis runs vertically, i.e. along a direction of gravitational force.
The feeding device has a weight-distribution sensing device. The weight-distribution sensing device is set up to sense a lateral distribution of a reel weight with respect to the reel axis. The weight-distribution sensing device is set up to determine the lateral distribution of the reel weight with respect to the reel axis. In this example, the reel weight represents a weight of the reel with or without an accommodated coil. The “lateral distribution” of the reel weight means the distribution of the reel weight transversely, in particular perpendicularly, to the reel axis. The reel weight may be laterally distributed evenly or unevenly with respect to the reel axis. If the reel weight is evenly distributed with respect to the reel axis, a center of gravity of the reel, with or without an accommodated coil, may be on the reel axis. If the reel weight is unevenly distributed with respect to the reel axis, the center of gravity of the reel, with or without an accommodated coil, may be at a radial distance from the reel axis. The uneven lateral distribution of the reel weight may be synonymously referred to as the eccentric arrangement of the reel weight with respect to the reel axis.
I recognized that an uneven lateral distribution of the reel weight with respect to the reel axis should be avoided as far as possible. The term “reel weight” represents both the weight of the reel with the coil, i.e. the weight in the loaded state, and the weight without an accommodated coil, that is to say the empty weight of the reel. Accordingly, an uneven distribution of the reel weight can result, for example, from the workpiece material being wound unevenly, for example, eccentrically on the reel. The uneven distribution of the reel weight with respect to the reel axis is manifested as an imbalance that can cause vibrations when the reel is rotated about the reel axis and lead to damage or, in the worst case, even destruction of the device.
The weight-distribution sensing device can be used to automatically detect whether the reel weight is laterally distributed evenly or unevenly with respect to the reel axis. In the event of an unfavorable uneven distribution of the reel weight, measures can consequently be taken to avoid operation of the device with an unevenly distributed reel weight. In this way, it can, for example, be avoided that the reel is rotated relative to the frame with a critically unevenly distributed reel weight. If necessary, an operator can be prompted to ensure a more even weight distribution so that the device can then be operated reliably and without interference.
In an example, the weight-distribution sensing device is set up to sense the reel weight. In addition to the sensing of the weight distribution, the weight-distribution sensing device thus allows sensing of the absolute reel weight. In this respect, the weight-distribution sensing device can also act as weighing scales. This can help prevent overloading of the reeling unit. In addition, the absolute reel weight can be monitored during operation of the device, that is to say when workpiece material is being removed from the reel, by the weight-distribution sensing device. In this way, a residual supply of workpiece material can be monitored, in particular continuously. Accordingly, replenishment of workpiece material can be provided in good time to keep downtimes of a forming machine supplied with the elongated workpiece low.
In a further example, the weight-distribution sensing device has at least one force sensor arranged at a radial distance from the reel axis. The force sensor is set up to sense a component of the reel weight that acts as a load on this force sensor. In other words, the force sensor can be used to sense the component of the reel weight acting at an off-axis position. In particular, the arrangement of the force sensor refers to a position of the measuring point at which the off-axially acting component of the reel weight is picked up. A sensitive unit of the force sensor may in this example be positioned in almost any way when a transmission device is used to transmit the off- axially acting component of the reel weight from the sensing point to the sensitive unit. Such a transmission device may be, for example, a linkage or a lever.
In a further example, the weight-distribution sensing device has at least three, in particular four, force sensors. For example, there are exactly three or exactly four force sensors. Each of the force sensors is in this example set up to sense a component of the reel weight that acts as a load on the respective force sensor. Preferably, the force sensors are arranged spaced apart from one another laterally, i.e. transversely, to the reel axis. In this way, the weight distribution of the reel can be sensed particularly precisely, in particular when the reel is at rest relative to the frame.
In a further example, the frame has at least three, in particular four, standing feet, which are used to place the device on an underlying surface. In a configuration of three standing feet, tilting of the device can be advantageously avoided, but a relatively large base area is required for the device to stand securely in terms of tilting. In contrast, a device with four standing feet can be placed securely in terms of tilting on a comparatively small base area. One or more of the standing feet may be height-adjustable to ensure the device can be set up securely in terms of tilting. At least one of the standing feet has a force sensor of the weight-distribution sensing device. For example, this standing foot with a force sensor may be formed by a load cell or weighing cell comprising the force sensor.
In a further example, the frame and the reel are connected to one another by a bearing unit of the weight-distribution sensing device. The bearing unit forms at least one force sensor of the sensing device. The force sensor therefore advantageously does not have to bear any additional weight such as, for instance, the weight of the frame.
In a further example, at least one force sensor of the weight-distribution sensing device has an elastically deformable deformation element that is elastically deformable depending on the component of the weight of the reel that acts as a load on this force sensor, with or without an accommodated coil. The deformation element is preferably designed in the form of an annular disc. The deformation element may be made to extend transversely to the reel axis. The force sensor also has a deformation detector. The deformation detector is attached to the deformation element to determine the deformation of the deformation element. The deformation detector may be, for example, a strain gauge or a piezoelectric element.
In a further example, the bearing unit has first supporting elements and second supporting elements. The deformation element is in this example arranged between the first supporting elements and the second supporting elements. The first supporting elements are arranged offset from the second supporting elements transversely to the reel axis. The reel in this example adjoins the first supporting elements. In contrast, the frame adjoins the second supporting elements. As a result of the offset arrangement of the first supporting elements in relation to the second supporting elements, the deformation element is consequently elastically deformed, in particular bent, depending on the reel weight. Unevennesses in the weight distribution can be sensed, because they are noticeably manifested as differences in the signals of the force sensors.
In a further example, the weight-distribution sensing device has at least one bearing device that supports a component of the reel weight. The bearing device may be designed in the manner of a hinge. In this example, the bearing device is arranged at a radial distance from at least one force sensor of the weight-distribution sensing device with respect to the reel axis. The force sensor is set up to sense the component of the reel weight that acts as a load on this force sensor. At least in a dynamic situation, in which the reel is rotated relative to the frame, an uneven distribution of the reel weight can consequently be detected by just one force sensor.
In a further example, at least one force sensor of the weight-distribution sensing device has a piezoelectric element and/or a strain gauge. Force sensors with piezoelectric elements are particularly compact. Force sensors with strain gauges prove to be particularly inexpensive to purchase.
In a further example, the weight-distribution sensing device has a torque sensor. Preferably, a force sensor of the sensing device and the torque sensor are integrated in a common sensor unit of the weight-distribution sensing device.
My retrofit kit is used to retrofit a basic device. The basic device is designed to feed an elongated workpiece to a forming machine, the basic device having a reeling unit with a frame and with a reel carried by the frame and intended to accommodate a workpiece supply in the form of a coil of workpiece material. The reel is mounted rotatably about a reel axis relative to the frame. In other words, the basic device corresponds to a feeding device and described above, dispensing with the weight-distribution sensing device of the feeding device. In this example, the retrofit kit has those components of the weight-distribution sensing device which is set up to sense a lateral distribution of a reel weight with respect to the reel axis. Accordingly, the basic device can be modified by retrofitting with the retrofit kit such that, after its modification, it corresponds to a feeding device. The advantages of the feeding device mentioned above and later can consequently be transferred by the retrofit kit to basic devices that are possibly already relatively older and have been used for quite a long time.
My forming installation has a forming machine that has a drawing-in device that can be operated with a varying drawing-in speed and draws in an elongated workpiece and conveys the workpiece to a tool area of the forming machine. The forming installation also has a feeding device as described above. Accordingly, the advantages of the feeding device explained above and further below are also transferred to the forming installation. The device is in this example set up to feed an elongated workpiece to the forming machine.
My method is used to operate my feeding devices as described above. By the method, the advantages of the device explained above or below can be exploited. According to the method, a lateral distribution of a reel weight with respect to the reel axis is determined. The lateral distribution of the reel weight is in this example determined by the weight-distribution sensing device of the device. If the determined distribution of the reel weight is greater than a predetermined weight-distribution tolerance value, one of the following steps is performed. Accordingly, if the aforementioned condition is met, either a warning message to warn against an imbalance may be issued, or a rotary movement of the reel relative to the frame stopped, or a handling instruction for balancing the coil output and/or a balancing of the coil with respect to the reel axis performed.
In an example of the method, in addition to determining the lateral distribution of the reel weight, the reel weight is determined in absolute terms.
In a further example of the method, the determined, in particular instantaneous or current, reel weight is displayed by a display device. For example, the display device is part of a forming machine, which in turn is part of a forming installation comprising the feeding device.
In a further example of the method, a warning message to warn against depletion of the workpiece supply is issued and-alternatively or in addition-an end of the coil remote from the drawing in is caught on the reel if the determined reel weight is equal to or less than a predetermined minimum weight. Alternatively or in addition, a warning message to warn against overloading of the feeding device is issued if the determined reel weight is equal to or greater than a predetermined maximum weight. Alternatively or in addition, a range of the workpiece supply is output on the basis of the determined reel weight if the determined reel weight is between the predetermined minimum weight and the predetermined maximum weight. Preferably, the range is output by a display device assigned to a forming machine, the forming machine being part of a forming installation comprising the feeding device.
In a further example of the method, when the method is carried out, the reel together with the coil is at least for a time turned about the reel axis relative to the frame. Workpiece material can in this example be removed from the workpiece supply while the reel is turning. Advantageously, a dynamic imbalance of the reel with or without an accommodated coil can be detected in this way, in particular if such a dynamic imbalance only occurs during removal of workpiece material. Alternatively or in addition, the method may be carried out as long as the reel together with the coil is at least for a time at rest relative to the frame. In this way, a static imbalance of the reel with or without an accommodated coil can be advantageously detected, in particular before the removal of workpiece material.
In a further example of the method, a control signal that controls a forming machine of a forming installation comprising the feeding device is generated. The control signal is in this example generated depending on the determined distribution of the reel weight.
In a further example of the method, the control signal is additionally generated depending on the determined reel weight.
Further advantages and aspects will become apparent from the appended claims and the description of examples, which are explained below on the basis of the figures. The same reference signs refer to components that are the same or similar or functionally the same.
The features mentioned above and still to be explained below can be used not only in the combination that is respectively specified but also in other combinations or on their own without departing from the scope of this disclosure.
The schematic
The wire processing installation 200 comprises a forming machine 100 in the form of a spring winding machine and a device 1 upstream in the direction of material flow to feed the elongated wire-shaped workpiece material to the forming machine 100. In this application, the device 1 is also referred to for short as the feeding device 1.
The forming machine 100 comprises a drawing-in device 101 connected to the control unit 104 of the forming machine 100. Under the control by an NC control program, the drawing-in device 101 conveys wire, which is fed by the feeding device 1, into the tool area 102 of the forming machine 100 equipped with forming tools (one or more). The forming tools downstream in the material conveying direction are used to form the fed wire into a helical spring or (in other forming machines) into another shaped part. After completion of the forming operation, the finished shaped part is separated from the fed wire under the control by the NC control program by a cutting device that is not shown. This process is cyclically repeated for each shaped part to be produced.
Advancement of the wire to the tool area 102 or the drawing in of the wire by the drawing-in device 101 is intended to take place according to a speed profile specific to the production process with a time-dependently varying drawing-in speed. Preferably, the drawing-in device 101 has at least one pair of drawing-in rollers, which has two drawing-in rollers, which are arranged with mutually parallel rotary axes and can be driven in opposite rotation by way of a controlled drive. Two or more synchronously operated pairs of drawing-in rollers are often provided to be able to transfer the advancement forces to the workpiece material in a manner that does not harm the material and without appreciable slippage. With their unprofiled or profiled circumferential surfaces, the drawing-in rollers delimit a drawing-in gap for leading the workpiece through. By controlling the rotational speed and direction of rotation of the drawing-in rollers, the rate of advancement and direction of advancement of the material to be processed can consequently be predetermined.
An insufficiently well controlled feed of wire can lead to considerable quality problems in spring winding machines, for example. In these forming machines, unlike in the bending process in wire bending machines, the forming force is applied to the forming tools directly from the drawing-in rollers of the drawing-in device 101 to press the workpiece against a winding tool and thus advance the winding process. In this process, any slippage there may be at the drawing-in rollers of the drawing-in device 101 can directly affect the quality of the final product. In unfavorable situations, the slippage at the drawing-in device 101 may be several per cent of the total drawing-in length in highly dynamic spring winding machines, which can cause the springs produced to become too short.
One task of the feeding device 1 may be to feed the wire to the drawing-in device of the forming machine 100 at any time as precisely as possible with the speed required at that time.
A workpiece supply 5 with a large length of the wire to be processed is provided in the form of a coil 6 in a reeling unit 2 of the device 1. In this example, the reeling unit 2 has a reel 4. In the examples of
The reeling unit 2 is an assembly separate from the forming machine 100. The frame 3 of the reeling unit 2 has, for example, a base plate with four adjusting feet arranged in a rectangular arrangement for placing on an underlying surface in the form of a hall floor. The frame 3 is also used for the mounting of the reel 4. The reel 4 may be mounted unlimitedly rotatably.
The reel 4 is only schematically shown in the figures. In its lower part, it comprises a plate-shaped or disc-shaped bundle holder on which a bundle of wire or a bundle of another workpiece can be placed. Four radially steplessly adjustable, upwardly projecting stanchions, with which the coil 6 can be centered after being laid in place on the bundle holder, are not shown. After the coil 6 has been laid in place, an upper terminating element similar to a wheel with radial spokes is fitted over a centering rod arranged coaxially to the reel axis H and is clamped in a certain height position.
During the operation of the forming machine 100, the wire is then gradually drawn off from the circumference of the wire coil 6 with the aid of its drawing-in device 101—and in this example with the assistance of the drive 15—the reel 4 being turned relative to the frame 3. In this example, any imbalance there may be of the reel 4 or of the accommodated coil 6 with respect to the rotation of the reel 4 about the reel axis H may mechanically induce the device 1 to vibrate. Such an imbalance may lead to increased bearing wear or even to failure of the device 1.
To counteract such an imbalance, the feeding device 1 has a weight-distribution sensing device 7. The weight-distribution sensing device 7 is set up to sense a lateral distribution of a reel weight with respect to the reel axis H. The reel weight in this example represents the weight of the reel 4 with or without an accommodated coil 6. The lateral distribution of the reel weight corresponds to the distribution of the reel weight transversely to the reel axis, that is to say the weight distribution in a horizontal plane. If the center of gravity of the reel 4 with or without an accommodated coil 6 is on the reel axis H, the reel weight is evenly distributed with respect to the reel axis H. If the center of gravity of the reel 4 with or without an accommodated coil 6 is at a radial distance from the reel axis H, the reel weight is unevenly distributed with respect to the reel axis H. The uneven distribution of the reel weight manifests itself as an undesirable imbalance when there is rotary movement of the reel 4 relative to the frame 3.
The weight-distribution sensing device 7 is set up in this example to sense not only the lateral distribution of the reel weight but also the absolute reel weight. The determined reel weight may in this example be displayed by a display device 103. For example, the instantaneous reel weight is continuously displayed during the operation of the feeding device 1, i.e. while the workpiece supply 5 is being removed. The display device 103 may be assigned to the forming machine 100. The forming machine 100 is part of a forming installation 200, which comprises the device 1.
Depending on the determined reel weight, various measures can be taken. For example, if the determined reel weight is equal to or less than a predetermined minimum weight, a warning message which warns against depletion of the workpiece supply 5 is issued. This will allow for timely replenishment. Alternatively or in addition, under the same condition an end of the coil remote from the drawing in may be caught on the reel 4. This prevents any further material from being drawn off. If the determined reel weight is equal to or greater than a predetermined maximum weight, for example, a warning message which indicates possible overloading of the device 1 may be issued. If the determined reel weight is between the predetermined minimum weight and the predetermined maximum weight, for example, a range of the workpiece supply is output. The range may in this example be output on the basis of the determined reel weight. The determined reel weight in this example therefore represents a workpiece supply still remaining in the reel 4. The range may be output, for example, by the display device 103.
In addition, various measures are, for example, carried out depending on the determined distribution of the reel weight. Accordingly, if the determined distribution of the reel weight is greater than a predetermined weight-distribution tolerance value, a warning message to warn against an imbalance may be issued. Alternatively or in addition, the rotary movement of the reel 4 relative to the frame 4 may be stopped. In addition, a handling instruction, as a result of which a balancing of the coil 6 with respect to the reel axis H is made possible, may be output. This handling instruction may give a worker indications as to how (i.e. in which direction) the workpiece material 50 must be moved in the workpiece supply 5 to achieve the most uniform possible distribution of the reel weight. Accordingly, depending on the determined distribution of the reel weight, a balancing operation of the coil 6 with respect to the reel axis H may be carried out.
The reel 4 may be turned relative to the frame 3 during the determination of the weight distribution or the absolute weight of the reel. When turning the reel 4 together with the coil 6, workpiece material 50 may in this example be removed from the workpiece supply 5. It is also possible to determine the weight distribution or the weight of the reel together with the coil 6 while the reel 4 is at rest relative to the frame 3. Combinations in which the reel 4 is turned and stopped at certain time intervals, while the weight distribution and/or the absolute weight are determined, are also possible.
Depending on the determined distribution of the reel weight, for example, a control signal used to control the forming machine 100 is generated. This control signal for the control of the forming machine 100 may also be generated depending on the determined absolute reel weight. In this way, the drawing-in device 101 may be stopped automatically if the determination of the reel weight indicates that the workpiece supply 50 of the coil 6 is tilting and/or if the determination of the weight distribution indicates that the reel weight is distributed too unevenly with respect to the reel axis H.
As already mentioned and can be seen in
The feeding device 1 may be produced, for example, by providing a basic device with a retrofit kit. In this example, the basic device is designed to feed the elongated workpiece 50 to the forming machine 100, the basic device having the reeling unit 2 with the frame 3 and with the reel 4 carried by the frame 3, the reel 4 being mounted rotatably about the reel axis H relative to the frame 3. The retrofit kit has the components of the weight-distribution sensing device 7. However, it is also possible that the feeding device 1 is supplied ex works with a weight-distribution sensing device 7.
The weight-distribution sensing devices 7 of the examples have a plurality of force sensors 8 arranged at a radial distance from the reel axis H (that is to say at an off-axis position), which each sense that component of the reel weight that acts as a load on this force sensor 8. Thus, in the example according to
The fact that a plurality of force sensors 8 are present allows a static determination of the distribution of the reel weight, that is to say while the reel 4 is at rest relative to the frame 3. This allows a static imbalance to be detected. Alternatively or in addition, a dynamic imbalance can be determined. The frame 3 in
In the example according to
In a further example of the device not shown in the figures, the weight-distribution sensing device 7 has at least one bearing device that supports a component of the reel weight. The bearing device may be designed in the manner of a hinge. In this example, the bearing device is arranged at a radial distance from at least one force sensor 8 of the weight-distribution sensing device 7 with respect to the reel axis H. This force sensor 8 is set up to sense a component of the reel weight that acts as a load on it. The reel weight is thus supported at least in one part on the bearing device and in another part on the force sensor 8. Depending on how these components of the reel weight relate to one another, an uneven distribution of the reel weight can be detected.
A force sensor 8 has, for example, a piezoelectric element and—alternatively or in addition—a strain gauge.
The weight-distribution sensing device 7 may also have a torque sensor. The torque sensor may be integrated in a sensor unit of the weight-distribution sensing device 7, in which, in addition to the torque sensor, a force sensor 8 is integrated.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2023 200 403.8 | Jan 2023 | DE | national |
