Patent ID: 12252367

DESCRIPTION OF EMBODIMENT

Hereinafter, a single-sheet lifter10according to an embodiment will be described with reference to the drawings.

A “loading area” refers to a three-dimensional area for loading a plurality of workpieces (sheet metals). “FF”, “FR”, “L”, “R”, “U”, and “D” in the drawings refer to a forward direction, a backward direction, a left direction, a right direction, an upper direction, and a downward direction, respectively.

As shown inFIGS.1and2, the single-sheet lifter10is a machine for lifting only an uppermost workpiece W among a plurality of the plate-shaped workpieces W loaded on a pallet P placed in a loading area TA. The single-sheet lifter10is installed on an L-shaped installation table12in a plan view provided in a vicinity of the loading area TA, and is located on the right side of the loading area TA. The single-sheet lifter10is a kind of air separator that separates the uppermost workpiece W by means of an injection pressure of air. The single-sheet lifter10is used when the plurality of workpieces W loaded on the pallet P in the loading area TA are sequentially supplied to a press brake (not shown) by a supply robot14.

The supply robot14is a kind of loading machine that supplies the workpieces W to the press brake. The supply robot14has, for example, the configuration disclosed in Patent Literature 3. The supply robot14includes an articulated robot arm16and a robot hand18as a workpiece suction lifter for sucking the workpiece W, which is attached to the tip of the robot arm16. The press brake is a working machine that bends the workpiece W, and is installed behind the loading area TA. On the right side of the loading area TA, in addition to the single-sheet lifter10, a double-sheet lifting detection machine (not shown) is also installed. The double-sheet lifting detection machine detects whether or not the robot hand18has sucked two or more workpieces W.

As shown inFIGS.3to6, the single-sheet lifter10includes a base frame20arranged on the installation table12. The base frame20extends vertically. The base frame20includes a pair of support plates22that are separated and opposed to each other in the front-rear direction, and a plurality of spacers24that connect the two support plates22. A first guide elongated hole22hextending vertically is formed on each of the support plates22. The upper portion of the first guide elongated hole22his curved so as to be away from the loading area TA. A second guide elongated hole22vextending vertically is formed on the right side of the first guide elongated hole22h.

A separation unit26that separates the uppermost workpiece W from other workpieces W by means of the injection pressure of air and the suction force is provided to the base frame20so as to be able to move up and down (move vertically). The specific configuration of the separation unit26will be described below.

The separation unit26includes a unit main body28provided to the base frame20so as to be able to move up and down. The unit main body28projects in a cantilevered manner with respect to the base frame20. At the base end of the unit main body28, two pairs of guide rollers30with flanges are rotatably provided around a horizontal axial center of rotation thereof. The guide rollers30in each of the pair are separated and opposed to each other in the front-rear direction. Each of the guide roller30is guided and supported by the first guide elongated hole22h.

At the tip of the unit main body28, a contact roller32as a contact member that comes into contact with the surface of the uppermost workpiece W from above is provided via a pair of brackets34. The contact roller32is rotatable around a horizontal axial center of rotation thereof, and is made of an elastic material such as urethane. A nozzle36for injecting air toward an edge of the uppermost workpiece W is provided in a vicinity of the base end of the unit main body28. The nozzle36is connected to an air supplying source (not shown) such as a supply pump that supplies the air.

A bellows type suction pad38for sucking a surface in a vicinity of the edge of the uppermost workpiece W from above is provided in the middle part of the unit main body28. The suction pad38is connected to an air suctioning source (not shown) such as a vacuum pump for sucking air. The suction pad38comes into contact with the surface of the uppermost workpiece W prior to the contact roller32. The separation unit26is configured to lift up the edge of the uppermost workpiece W using the contact roller32as a fulcrum when the suction pad38executes a sucking operation in a state in which the contact roller32is in contact with the surface of the uppermost workpiece W (seeFIG.7A).

The separation unit26is configured to go up following a lifting operation (an ascending operation) of the robot hand18and be retracted from above the loading area TA when the robot hand18lifts the uppermost workpiece W. Further, when the separation unit26retracted from above the loading area TA falls due to its own weight, the separation unit26returns to the position above the plurality of workpieces W loaded in the loading area TA via the pallet P.

Note that either the nozzle36or the suction pad38may be omitted from the separation unit26. In this case, the separation unit26separates the uppermost workpiece W from the other workpieces W by means of either the injection pressure of the air or the suction force.

At the upper part between the pair of support plates22, a first sprocket40as a rotating wheel is rotatably provided around a horizontal axial center of rotation thereof. Each end portion of a rotating shaft42of the first sprocket40is rotatably supported at the upper part of the support plate22via a support ring44. The first sprocket40is not able to move up and down with respect to the support plate22. Further, on the right side of the first sprocket40in the base frame20, a second sprocket46as a second rotating wheel is provided so as to be able to move up and down, and rotate around a horizontal axial center of rotation thereof. Each end portion of a rotating shaft48of the second sprocket46is supported by the second guide elongated hole22vof the support plate22so as to be able to rotate and move up and down.

A connecting chain50as a linear connecting member is provided between the pair of support plates22. One end of the connecting chain50is connected to the base end of the separation unit26. The other end of the connecting chain50is connected to the upper right portion of the base frame20. The vicinity of the one end of the connecting chain50is hung around the first sprocket40. The vicinity of the other end of the connecting chain50is hung around the second sprocket46so as to suspend the second sprocket46.

Instead of respectively using the first sprocket40and the second sprocket46as the first and second rotating wheels, a first pulley (not shown) and a second pulley (not shown) may be used as the first and second rotating wheels, respectively. In this case, instead of using the connecting chain50as the linear connecting member, a connecting belt (not shown) is used as a band-shaped connecting member.

A counter balancer52that reduces a weight acting on the separation unit26is provided at each end portion of the rotating shaft48of the second sprocket46. Each of the counter balancers52includes a plurality of weights54that apply gravity as a downward force to the second sprocket46. The counter balancer52is configured to be rotatable with respect to the support plate22. That is, the counter balancer52is configured to be rotatable relative to the rotating shaft48of the second sprocket46.

In lieu of the counter balancer52that includes the plurality of weights54, as another counter balancer that reduces the weight acting on the separation unit26, a coil spring (not shown) that applies an urging force as the downward force to the second sprocket46may be used. In this case, the coil spring is provided between each end portion of the rotating shaft48of the second sprocket46and the support plate22.

The single-sheet lifter10includes an assist unit56for assisting a falling operation (a descending operation) due to the own weight of the separation unit26that is retracted from above the loading area TA. The specific configuration of the assist unit56will be described below.

The base end of a swing lever58is integrally connected to one end of the rotating shaft42of the first sprocket40. An air cylinder60as an assist actuator is attached via a bracket62to the support plate22on the front side. The air cylinder60includes an operation rod64that can move vertically. The assist unit56is configured such that the air cylinder60is driven to cause the operation rod64to push the tip of the swing lever58from below, which is applied to the first sprocket40for promoting the falling operation of the separation unit26.

Subsequently, the operation and effect of the single-sheet lifter10will be described.

(Overall Operation of the Single-Sheet Lifter10and the Supply Robot14)

As shown inFIGS.1and7A, by causing the robot hand18to go down in the loading area TA, the surface of the uppermost workpiece W is sucked by the robot hand18. Then, by executing the sucking operation of the suction pad38in a state in which the contact roller32is in contact with the surface of the uppermost workpiece W, the edge of the uppermost workpiece W is lifted up using the contact roller32as a fulcrum. Further, the air is injected from the nozzle36toward the edge of the uppermost workpiece W. As the result of this, the uppermost workpiece W is separated from the other workpieces W by means of the injection pressure of the air and the suction force, which makes it possible for the robot hand18to easily lift only the uppermost workpiece W. After the uppermost workpiece W is lifted, the sucking operation of the suction pad38and the injecting operation of the air from the nozzle36are stopped.

As shown inFIG.7B, when the robot hand18is caused to go up to lift the uppermost workpiece W, the separation unit26is also caused to go up following the lifting operation of the robot hand18, and is guided by the first guide elongated hole22hand retracted from above the loading area TA. As a result of this, the workpiece W sucked by the robot hand18of the supply robot14is supplied to the press brake without being hindered by the separation unit26.

After the separation unit26is retracted from above the loading area TA, the air cylinder60is driven to cause the operation rod64to press the tip of the swing lever58from below, as shown inFIG.7C. As the result of this, a rotational force that promotes the falling operation of the separation unit26is applied to the first sprocket40. The separation unit26falls due to its own weight and returns to the position above the plurality of workpieces W loaded in the loading area TA.

By repeating the operations described above, the plurality of workpieces W loaded in the loading area TA can be sequentially supplied to the press brake by the supply robot14.

(Particular Effect of the Single-Sheet Lifter10)

The separation unit26is configured to lift up the edge of the uppermost workpiece W using the contact roller32as a fulcrum when the suction pad38executes the sucking operation in a state in which the contact roller32is in contact with the surface of the uppermost workpiece W. This makes it possible for the uppermost workpiece W to be easily separated from the other workpieces W. As a result, it is possible for the robot hand18to reliably lift only the uppermost workpiece W.

The separation unit26separates the uppermost workpiece W from the other workpieces W by way of the injection pressure of the air and the suction force. Therefore, even when the workpiece W is a non-magnetic body, it is possible for the robot hand18to lift only the uppermost workpiece W. In other words, regardless of the material of the workpiece W, it is possible for the robot hand18to lift only the uppermost workpiece W.

The one end of the connecting chain50is connected to the base end of the separation unit26, and the other end of the connecting chain50is connected to the upper right side of the base frame20. The vicinity of the one end of the connecting chain50is hung around the first sprocket40. The vicinity of the other end of the connecting chain50is hung around the second sprocket46so as to suspend the second sprocket46. The counter balancer52that reduces the weight acting on the separation unit26is provided at each of the end portions of the rotating shaft48of the second sprocket46. Therefore, even if the weight of the separation unit26is large and the rigidity of the workpiece W is small, it is possible to support the separation unit26sufficiently from below without plastically deforming the vicinity of the edge of the workpiece W when the uppermost workpiece W is lifted. Further, even if the weight of the separation unit26is large, the impact when the separation unit26falls can be sufficiently reduced to prevent the workpieces W loaded in the loading area TA from being scratched.

Therefore, according to the present embodiment, regardless of the material of the workpiece W, it is possible for the robot hand18to stably lift only the uppermost workpiece W without damaging the workpiece W.

Further, since the assist unit56assists the falling operation due to the own weight of the separation unit26, it is possible to reliably return the separation unit26to the position above the plurality of workpieces W loaded in the loading area TA. Further, since the contact roller32is rotatable around the horizontal axial center of rotation thereof, even if the end portion of the workpiece W interferes with the contact roller32when the workpiece W is lifted by the robot hand18, the contact roller32does not hinder the workpiece W from being lifted.

Therefore, according to the present embodiment, it is possible for the supply robot14to sequentially and stably supply, to the press brake, the plurality of workpieces W loaded in the loading area TA.

Modified Example of the Present Embodiment

As shown inFIG.8, a single-sheet lifter10A according to a modified example is a machine for lifting only the uppermost workpiece W among the plurality of the workpieces W loaded on the pallet P placed in the loading area TA, in the same manner as the single-sheet lifter10described above (seeFIG.3). The single-sheet lifter10A includes an assist unit66having a configuration different from that of the assist unit56(seeFIG.3). Other configurations are the same as those of the single-sheet lifter10. The specific configuration of the assist unit66will be described below. The same reference numerals will be given to the components that are the same as or equivalent to those of the single-sheet lifter10described above, and a detailed description thereof will be omitted.

An L-shaped operating link68is provided above the second guide elongated hole22vin the support plate22on the front side so as to be swingable around a horizontal axial center of swinging (an axial center of a swinging shaft70). On the right side of the second guide elongated hole22v, an air cylinder72as an assist actuator is attached to the support plate22via a bracket74. The air cylinder72includes an operation rod76that can move vertically. A rotatable connecting pin78is attached to the tip of the operation rod76. The connecting pin78is connected to an elongated hole (not shown) formed at a first tip (one end) of the operating link68. The assist unit66is configured such that a rotational force that promotes the falling operation of the separation unit26is applied to the unit main body28when the air cylinder72is driven to cause a second tip (the other end) of the operating link68to push the unit main body28from the right side.

Then, also in the modified example of the present embodiment, the same action and effect as the action and effect of the present embodiment described above are exhibited.

In the single-sheet lifter10(10A) according to the embodiment and modified example described above, the separation unit26is configured to go up following the lifting operation of the robot hand18and be retracted from above the loading area TA when the robot hand18(the workpiece suction lifter) of the supply robot14(the loading machine) sucks the surface of the uppermost workpiece W to lift the workpiece W. For this reason, the workpiece W sucked by the robot hand18of the supply robot14can be supplied to the press brake without being hindered by the separation unit26. Since the separation unit26does not hinder the workpiece W from moving, it is possible to prevent the workpiece W from being damaged.

Further, the separation unit26includes the contact roller32(the contact member) that comes into contact with the surface of the uppermost workpiece W. For this reason, when the uppermost workpiece W is separated by means of at least one of the injection pressure of the air and the suction force, separation from the other workpieces W by lifting up the edge of the uppermost workpiece W can be easier. As a result, it is possible to reliably and stably lift only the upper workpiece W. Here, since the uppermost workpiece W is separated by means of at least one of the injection pressure of the air and the suction force, it is possible to reliably and stably lift only the uppermost workpiece W even when the workpiece W is a non-magnetic body, that is, when it is made of any raw material.

Further, the single-sheet lifter10(10A) also includes the counter balancer52that reduces the weight acting on the separation unit26. For this reason, when the workpiece W is lifted by the robot hand18, the weight of the separation unit26acting on the workpiece W can be alleviated by the counter balancer52, and the deformation of the low-rigid workpiece W can be prevented. At the same time, the retracting operation of the separation unit26as the workpiece W goes up can be performed smoothly. Further, when the retracted separation unit26is caused to fall and return above the loaded workpieces W, the falling operation can be alleviated by the counter balancer52. As a result, it is possible to prevent the workpiece W from being damaged.

The single-sheet lifter10(10A) according to the embodiment and modified example described above further include the first sprocket40(the first rotating wheel) and the second sprocket46(the second rotating wheel), and the linear connecting chain50(the connecting member) that are described above. The connecting chain50is hung around the first sprocket40and the second sprocket46, the second sprocket46is suspended by the connecting chain50, and the counter balancer52applies the downward force to the second sprocket46. With this configuration, the weight of the separation unit26can be effectively reduced by the downward force applied to the second sprocket46. Note that as described above, the first pulley may be used as the first rotating wheel, the second pulley may be used as the second rotating wheel, and the band-shaped connecting belt may be used as the connecting member.

Here, the separation unit26includes the bellows type suction pad38for sucking the surface in the vicinity of the edge of the uppermost workpiece W, For this reason, when the suction pad38is operated in a state in which the contact roller32(the contact member) is in contact with the surface of the uppermost workpiece W, it is possible to lift up the edge of the uppermost workpiece W using the contact roller32as a fulcrum. That is, it is possible to separate the uppermost workpiece W more reliably.

Here, the separation unit26includes the nozzle36for injecting the air toward the edge of the uppermost workpiece W. For this reason, by injecting the air from the nozzle36, it is possible to lift up the edge of the uppermost workpiece W, using the contact roller32as a fulcrum, by means of the injection pressure thereof. That is, it is possible to separate the uppermost workpiece W more reliably.

Further, the single-sheet lifter10(10A) according to the embodiment and modified example described above further include the assist unit56(66) for assisting the falling operation due to the own weight of the retracted separation unit26. For this reason, it is possible to return the separation unit26above the loaded workpieces W easily and quickly.

Furthermore, in the single-sheet lifter10(10A) according to the embodiment and modified example described above, the contact member is the contact roller32that is rotatable around the horizontal axial center of rotation. When the workpiece W is lifted by the robot hand18, even if the workpiece W interferes with the contact roller32located at the tip of the separation unit26, the contact roller32rotates so that the workpiece W is away from the contact roller32with the movement thereof not being hindered. Therefore, it is possible to prevent the workpiece W from being damaged, and the supply of the workpieces W is not hindered.

The present invention is not limited to the embodiment and modified example described above. For example, in the embodiment and modified example described above, the uppermost workpiece W is separated from the other workpieces W by using both the injection pressure of the air and the suction force. However, only at least one of the injection pressure of the air (the nozzle36) and the suction force (the suction pad38) may be used. Further, in lieu of the assist unit56(66) including the air cylinder60(72), an assist unit including an electric motor or a belt mechanism may be used. In this case, the assist unit assists the falling operation due to the own weight of the separation unit26by driving the electric motor or the belt mechanism.