Patent Description:
When a plurality of workpieces loaded in a loading area are sequentially supplied to a working machine such as a press brake by a loading machine such as a supply robot, a magnet floater installed in a vicinity of the loading area is used. The magnet floater makes it easier to separate the uppermost workpiece by levitating, with a magnetic force, several upper workpieces among the plurality of workpieces loaded in the loading area (see Patent Literature <NUM> described below). When the workpiece is a non-magnetic body, it is not possible to levitate the workpieces with the magnetic force, and it is difficult to separate only the uppermost workpiece by a workpiece suction lifter of the loading machine.

An air separator installed in the vicinity of the loading area may be used. The air separator separates the uppermost workpiece among the plurality of workpieces loaded in the loading area with a jet pressure of air (see Patent Literature <NUM> described below). The air separator includes a base frame installed in the vicinity of the loading area and extending vertically, and a separation unit provided to the base frame so as to be able to move up and down. The uppermost workpiece is separated from other workpieces by the pressure of the air injected from the separation unit. The separation unit includes a contact member that comes into contact with the surface of the uppermost workpiece and a nozzle for injecting the air toward the edge of the uppermost workpiece. When the workpiece suction lifter of the loading machine sucks the surface of the uppermost workpiece to lift the workpiece, the separation unit goes up following the lifting operation of the workpiece suction lifter and is retracted from above the loading area. When the separation unit retracted from above the loading area falls due to its own weight, the separation unit returns to a position above the plurality of workpieces loaded in the loading area.

Note that in addition to Patent Literatures <NUM> and <NUM>, Patent Literature <NUM> described below also discloses a technique related to the present invention. Patent Literature <NUM> relates to an improvement of the workpiece suction lifter. Patent Literature <NUM> provides a further single-sheet lifter according to the prior art.

If the air separator is used, the weight of the separation unit becomes large. If the weight of the separation unit is large, the workpiece loaded in the loading area may be scratched due to the impact when the separation unit falls. Further, if the rigidity of the workpiece is small, the vicinity of the edge of the workpiece may be deflected and plastically deformed by the pressure of the air when the workpiece suction lifter lifts the uppermost workpiece. Regarding the air separator, an improvement is desired in stably lifting the uppermost workpiece while preventing the workpiece from being damaged.

An object of the present invention is to provide a single-sheet lifter according to claim <NUM>, capable of stably lifting the uppermost workpiece while preventing the workpiece from being damaged.

According to one aspect of the present invention, there is provided a single-sheet lifter including a base frame arranged in a vicinity of a loading area and extending vertically, a separation unit provided to the base frame so as to be able to move up and down (move vertically), the separation unit including a contact member that comes into contact with a surface of an uppermost workpiece among a plurality of the workpieces loaded in the loading area, the separation unit being configured to go up following a lifting operation (an ascending operation) of a workpiece suction lifter of a loading machine and be retracted from above the loading area when the workpiece suction lifter sucks the surface of the uppermost workpiece to lift the workpiece, and configured to separate the uppermost workpiece from other workpieces by means of at least one of an injection pressure of air and a suction force, and a counter balancer configured to reduce a weight acting on the separation unit, wherein the single-sheet lifter further includes a first rotating wheel provided to the base frame so as to be able to rotate, a second rotating wheel provided to the base frame so as to be able to rotate and move up and down, and a linear or band-shaped connecting member including one end connected to the separation unit and another end connected to the base frame, the connecting member being hung around the first rotating wheel, and hung around the second rotating wheel so as to suspend the second rotating wheel. In this case, the counter balancer is configured to apply a downward force to the second rotating wheel.

The separation unit may include a bellows type suction pad for sucking a surface in a vicinity of an edge of the uppermost workpiece. In this case, the separation unit is configured to lift up the edge of the uppermost workpiece using the contact member as a fulcrum when the suction pad executes a sucking operation in a state in which the contact member is in contact with the surface of the uppermost workpiece. Further, the separation unit may include a nozzle for injecting the air toward the edge of the uppermost workpiece.

The single-sheet lifter may further include an assist unit for assisting a falling operation (a descending operation) due to an own weight of the
separation unit that is retracted from the upper side of the loading area. Further, the contact member may be a contact roller rotatable around a horizontal axial center of rotation.

Hereinafter, a single-sheet lifter <NUM> according 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 in <FIG> and <FIG>, the single-sheet lifter <NUM> is 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 lifter <NUM> is installed on an L-shaped installation table <NUM> in 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 lifter <NUM> is a kind of air separator that separates the uppermost workpiece W by means of an injection pressure of air. The single-sheet lifter <NUM> is 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 robot <NUM>.

The supply robot <NUM> is a kind of loading machine that supplies the workpieces W to the press brake. The supply robot <NUM> has, for example, the configuration disclosed in Patent Literature <NUM>. The supply robot <NUM> includes an articulated robot arm <NUM> and a robot hand <NUM> as a workpiece suction lifter for sucking the workpiece W, which is attached to the tip of the robot arm <NUM>. 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 lifter <NUM>, a double-sheet lifting detection machine (not shown) is also installed. The double-sheet lifting detection machine detects whether or not the robot hand <NUM> has sucked two or more workpieces W.

As shown in <FIG>, the single-sheet lifter <NUM> includes a base frame <NUM> arranged on the installation table <NUM>. The base frame <NUM> extends vertically. The base frame <NUM> includes a pair of support plates <NUM> that are separated and opposed to each other in the front-rear direction, and a plurality of spacers <NUM> that connect the two support plates <NUM>. A first guide elongated hole <NUM> extending vertically is formed on each of the support plates <NUM>. The upper portion of the first guide elongated hole <NUM> is curved so as to be away from the loading area TA. A second guide elongated hole 22v extending vertically is formed on the right side of the first guide elongated hole <NUM>.

A separation unit <NUM> that 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 frame <NUM> so as to be able to move up and down (move vertically). The specific configuration of the separation unit <NUM> will be described below.

The separation unit <NUM> includes a unit main body <NUM> provided to the base frame <NUM> so as to be able to move up and down. The unit main body <NUM> projects in a cantilevered manner with respect to the base frame <NUM>. At the base end of the unit main body <NUM>, two pairs of guide rollers <NUM> with flanges are rotatably provided around a horizontal axial center of rotation thereof. The guide rollers <NUM> in each of the pair are separated and opposed to each other in the front-rear direction. Each of the guide roller <NUM> is guided and supported by the first guide elongated hole <NUM>.

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

A bellows type suction pad <NUM> for 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 body <NUM>. The suction pad <NUM> is connected to an air suctioning source (not shown) such as a vacuum pump for sucking air. The suction pad <NUM> comes into contact with the surface of the uppermost workpiece W prior to the contact roller <NUM>. The separation unit <NUM> is configured to lift up the edge of the uppermost workpiece W using the contact roller <NUM> as a fulcrum when the suction pad <NUM> executes a sucking operation in a state in which the contact roller <NUM> is in contact with the surface of the uppermost workpiece W (see <FIG>).

The separation unit <NUM> is configured to go up following a lifting operation (an ascending operation) of the robot hand <NUM> and be retracted from above the loading area TA when the robot hand <NUM> lifts the uppermost workpiece W. Further, when the separation unit <NUM> retracted from above the loading area TA falls due to its own weight, the separation unit <NUM> returns to the position above the plurality of workpieces W loaded in the loading area TA via the pallet P.

Note that either the nozzle <NUM> or the suction pad <NUM> may be omitted from the separation unit <NUM>. In this case, the separation unit <NUM> separates 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 plates <NUM>, a first sprocket <NUM> as a rotating wheel is rotatably provided around a horizontal axial center of rotation thereof. Each end portion of a rotating shaft <NUM> of the first sprocket <NUM> is rotatably supported at the upper part of the support plate <NUM> via a support ring <NUM>. The first sprocket <NUM> is not able to move up and down with respect to the support plate <NUM>. Further, on the right side of the first sprocket <NUM> in the base frame <NUM>, a second sprocket <NUM> as 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 shaft <NUM> of the second sprocket <NUM> is supported by the second guide elongated hole 22v of the support plate <NUM> so as to be able to rotate and move up and down.

A connecting chain <NUM> as a linear connecting member is provided between the pair of support plates <NUM>. One end of the connecting chain <NUM> is connected to the base end of the separation unit <NUM>. The other end of the connecting chain <NUM> is connected to the upper right portion of the base frame <NUM>. The vicinity of the one end of the connecting chain <NUM> is hung around the first sprocket <NUM>. The vicinity of the other end of the connecting chain <NUM> is hung around the second sprocket <NUM> so as to suspend the second sprocket <NUM>.

Instead of respectively using the first sprocket <NUM> and the second sprocket <NUM> as 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 chain <NUM> as the linear connecting member, a connecting belt (not shown) is used as a band-shaped connecting member.

A counter balancer <NUM> that reduces a weight acting on the separation unit <NUM> is provided at each end portion of the rotating shaft <NUM> of the second sprocket <NUM>. Each of the counter balancers <NUM> includes a plurality of weights <NUM> that apply gravity as a downward force to the second sprocket <NUM>. The counter balancer <NUM> is configured to be rotatable with respect to the support plate <NUM>. That is, the counter balancer <NUM> is configured to be rotatable relative to the rotating shaft <NUM> of the second sprocket <NUM>.

In lieu of the counter balancer <NUM> that includes the plurality of weights <NUM>, as another counter balancer that reduces the weight acting on the separation unit <NUM>, a coil spring (not shown) that applies an urging force as the downward force to the second sprocket <NUM> may be used. In this case, the coil spring is provided between each end portion of the rotating shaft <NUM> of the second sprocket <NUM> and the support plate <NUM>.

The single-sheet lifter <NUM> includes an assist unit <NUM> for assisting a falling operation (a descending operation) due to the own weight of the separation unit <NUM> that is retracted from above the loading area TA. The specific configuration of the assist unit <NUM> will be described below.

The base end of a swing lever <NUM> is integrally connected to one end of the rotating shaft <NUM> of the first sprocket <NUM>. An air cylinder <NUM> as an assist actuator is attached via a bracket <NUM> to the support plate <NUM> on the front side. The air cylinder <NUM> includes an operation rod <NUM> that can move vertically. The assist unit <NUM> is configured such that the air cylinder <NUM> is driven to cause the operation rod <NUM> to push the tip of the swing lever <NUM> from below, which is applied to the first sprocket <NUM> for promoting the falling operation of the separation unit <NUM>.

Subsequently, the operation and effect of the single-sheet lifter <NUM> will be described.

As shown in <FIG> and <FIG>, by causing the robot hand <NUM> to go down in the loading area TA, the surface of the uppermost workpiece W is sucked by the robot hand <NUM>. Then, by executing the sucking operation of the suction pad <NUM> in a state in which the contact roller <NUM> is in contact with the surface of the uppermost workpiece W, the edge of the uppermost workpiece W is lifted up using the contact roller <NUM> as a fulcrum. Further, the air is injected from the nozzle <NUM> toward 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 hand <NUM> to easily lift only the uppermost workpiece W. After the uppermost workpiece W is lifted, the sucking operation of the suction pad <NUM> and the injecting operation of the air from the nozzle <NUM> are stopped.

As shown in <FIG>, when the robot hand <NUM> is caused to go up to lift the uppermost workpiece W, the separation unit <NUM> is also caused to go up following the lifting operation of the robot hand <NUM>, and is guided by the first guide elongated hole <NUM> and retracted from above the loading area TA. As a result of this, the workpiece W sucked by the robot hand <NUM> of the supply robot <NUM> is supplied to the press brake without being hindered by the separation unit <NUM>.

After the separation unit <NUM> is retracted from above the loading area TA, the air cylinder <NUM> is driven to cause the operation rod <NUM> to press the tip of the swing lever <NUM> from below, as shown in <FIG>. As the result of this, a rotational force that promotes the falling operation of the separation unit <NUM> is applied to the first sprocket <NUM>. The separation unit <NUM> falls 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 robot <NUM>.

The separation unit <NUM> is configured to lift up the edge of the uppermost workpiece W using the contact roller <NUM> as a fulcrum when the suction pad <NUM> executes the sucking operation in a state in which the contact roller <NUM> is 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 hand <NUM> to reliably lift only the uppermost workpiece W.

The separation unit <NUM> separates 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 hand <NUM> to lift only the uppermost workpiece W. In other words, regardless of the material of the workpiece W, it is possible for the robot hand <NUM> to lift only the uppermost workpiece W.

The one end of the connecting chain <NUM> is connected to the base end of the separation unit <NUM>, and the other end of the connecting chain <NUM> is connected to the upper right side of the base frame <NUM>. The vicinity of the one end of the connecting chain <NUM> is hung around the first sprocket <NUM>. The vicinity of the other end of the connecting chain <NUM> is hung around the second sprocket <NUM> so as to suspend the second sprocket <NUM>. The counter balancer <NUM> that reduces the weight acting on the separation unit <NUM> is provided at each of the end portions of the rotating shaft <NUM> of the second sprocket <NUM>. Therefore, even if the weight of the separation unit <NUM> is large and the rigidity of the workpiece W is small, it is possible to support the separation unit <NUM> sufficiently 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 unit <NUM> is large, the impact when the separation unit <NUM> falls 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 hand <NUM> to stably lift only the uppermost workpiece W without damaging the workpiece W.

Further, since the assist unit <NUM> assists the falling operation due to the own weight of the separation unit <NUM>, it is possible to reliably return the separation unit <NUM> to the position above the plurality of workpieces W loaded in the loading area TA. Further, since the contact roller <NUM> is rotatable around the horizontal axial center of rotation thereof, even if the end portion of the workpiece W interferes with the contact roller <NUM> when the workpiece W is lifted by the robot hand <NUM>, the contact roller <NUM> does not hinder the workpiece W from being lifted.

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

As shown in <FIG>, a single-sheet lifter 10A 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 lifter <NUM> described above (see <FIG>). The single-sheet lifter 10A includes an assist unit <NUM> having a configuration different from that of the assist unit <NUM> (see <FIG>). Other configurations are the same as those of the single-sheet lifter <NUM>. The specific configuration of the assist unit <NUM> will 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 lifter <NUM> described above, and a detailed description thereof will be omitted.

An L-shaped operating link <NUM> is provided above the second guide elongated hole 22v in the support plate <NUM> on the front side so as to be swingable around a horizontal axial center of swinging (an axial center of a swinging shaft <NUM>). On the right side of the second guide elongated hole 22v, an air cylinder <NUM> as an assist actuator is attached to the support plate <NUM> via a bracket <NUM>. The air cylinder <NUM> includes an operation rod <NUM> that can move vertically. A rotatable connecting pin <NUM> is attached to the tip of the operation rod <NUM>. The connecting pin <NUM> is connected to an elongated hole (not shown) formed at a first tip (one end) of the operating link <NUM>. The assist unit <NUM> is configured such that a rotational force that promotes the falling operation of the separation unit <NUM> is applied to the unit main body <NUM> when the air cylinder <NUM> is driven to cause a second tip (the other end) of the operating link <NUM> to push the unit main body <NUM> from 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 lifter <NUM> (10A) according to the embodiment and modified example described above, the separation unit <NUM> is configured to go up following the lifting operation of the robot hand <NUM> and be retracted from above the loading area TA when the robot hand <NUM> (the workpiece suction lifter) of the supply robot <NUM> (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 hand <NUM> of the supply robot <NUM> can be supplied to the press brake without being hindered by the separation unit <NUM>. Since the separation unit <NUM> does not hinder the workpiece W from moving, it is possible to prevent the workpiece W from being damaged.

Further, the separation unit <NUM> includes the contact roller <NUM> (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 lifter <NUM> (10A) also includes the counter balancer <NUM> that reduces the weight acting on the separation unit <NUM>. For this reason, when the workpiece W is lifted by the robot hand <NUM>, the weight of the separation unit <NUM> acting on the workpiece W can be alleviated by the counter balancer <NUM>, and the deformation of the low-rigid workpiece W can be prevented. At the same time, the retracting operation of the separation unit <NUM> as the workpiece W goes up can be performed smoothly. Further, when the retracted separation unit <NUM> is caused to fall and return above the loaded workpieces W, the falling operation can be alleviated by the counter balancer <NUM>. As a result, it is possible to prevent the workpiece W from being damaged.

The single-sheet lifter <NUM> (10A) according to the embodiment and modified example described above further include the first sprocket <NUM> (the first rotating wheel) and the second sprocket <NUM> (the second rotating wheel), and the linear connecting chain <NUM> (the connecting member) that are described above. The connecting chain <NUM> is hung around the first sprocket <NUM> and the second sprocket <NUM>, the second sprocket <NUM> is suspended by the connecting chain <NUM>, and the counter balancer <NUM> applies the downward force to the second sprocket <NUM>. With this configuration, the weight of the separation unit <NUM> can be effectively reduced by the downward force applied to the second sprocket <NUM>. 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 unit <NUM> includes the bellows type suction pad <NUM> for sucking the surface in the vicinity of the edge of the uppermost workpiece W. For this reason, when the suction pad <NUM> is operated in a state in which the contact roller <NUM> (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 roller <NUM> as a fulcrum. That is, it is possible to separate the uppermost workpiece W more reliably.

Here, the separation unit <NUM> includes the nozzle <NUM> for injecting the air toward the edge of the uppermost workpiece W. For this reason, by injecting the air from the nozzle <NUM>, it is possible to lift up the edge of the uppermost workpiece W, using the contact roller <NUM> as 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 lifter <NUM> (10A) according to the embodiment and modified example described above further include the assist unit <NUM> (<NUM>) for assisting the falling operation due to the own weight of the retracted separation unit <NUM>. For this reason, it is possible to return the separation unit <NUM> above the loaded workpieces W easily and quickly.

Furthermore, in the single-sheet lifter <NUM> (10A) according to the embodiment and modified example described above, the contact member is the contact roller <NUM> that is rotatable around the horizontal axial center of rotation. When the workpiece W is lifted by the robot hand <NUM>, even if the workpiece W interferes with the contact roller <NUM> located at the tip of the separation unit <NUM>, the contact roller <NUM> rotates so that the workpiece W is away from the contact roller <NUM> with 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.

Claim 1:
A single-sheet lifter (<NUM>, 10A) comprising:
a base frame (<NUM>) arranged in a vicinity of a loading area (TA) and extending vertically;
a separation unit (<NUM>) provided to the base frame (<NUM>) so as to be able to move up and down, the separation unit (<NUM>) including a contact member (<NUM>) that comes into contact with a surface of an uppermost workpiece (W) among a plurality of the workpieces (W) loaded in the loading area (TA), the separation unit (<NUM>) being configured to go up following a lifting operation of a workpiece suction lifter (<NUM>) of a loading machine (<NUM>) and be retracted from above the loading area (TA) when the workpiece suction lifter (<NUM>) sucks the surface of the uppermost workpiece (W) to lift the workpiece (W), and configured to separate the uppermost workpiece (W) from other workpieces (W) by means of at least one of an injection pressure of air and a suction force; and
a counter balancer (<NUM>) configured to reduce a weight acting on the separation unit (<NUM>) characterized in that:
the single-sheet lifter (<NUM>, 10A) further comprising:
a first rotating wheel (<NUM>) provided to the base frame (<NUM>) so as to be able to rotate;
a second rotating wheel (<NUM>) provided to the base frame (<NUM>) so as to be able to rotate and move up and down; and
a linear or band-shaped connecting member (<NUM>) including one end connected to the separation unit (<NUM>) and another end connected to the base frame (<NUM>), the connecting member (<NUM>) being hung around the first rotating wheel (<NUM>), and hung around the second rotating wheel (<NUM>) so as to suspend the second rotating wheel (<NUM>), wherein
the counter balancer (<NUM>) is configured to apply a downward force to the second rotating wheel (<NUM>).