Pallet loader and manipulator

A pallet load stand and manipulator allows a pallet to receive a workpiece and the workpiece to be clamped to the pallet while the pallet is in a horizontal position. Once the workpiece has been clamped to the pallet, the pallet may be rotated to a vertical position so that the pallet may be loaded onto a machine tool that operates on a workpiece with the pallet in the vertical position. The pallet may also be rotated to an intermediate position, similar to an artist's easel, in which the pallet is held in an inclined position, between the horizontal and vertical positions by positive locating assemblies and positive stops.

FIELD OF THE INVENTION

The pallet loader and manipulator may be loaded with a pallet in a horizontal position and can be used to re-orient the pallet to the vertical position for loading the pallet and the workpiece into a machine tool.

BACKGROUND OF THE INVENTION

Certain machine tools such as plate mills operate on a workpiece with the pallet oriented in the vertical position. If the workpiece is large, mounting the workpiece on the pallet with the pallet in the vertical position can be a difficult task. The workpiece has to be supported against the force of gravity while it is being clamped to the pallet. Additionally, when the pallet is in a vertical position, it may be physically difficult to reach the top of the pallet in order to align the workpiece along the top edge of the pallet and to actuate the clamps along the top of the pallet to secure the workpiece to the pallet.

BRIEF SUMMARY OF THE INVENTION

A pallet load stand and manipulator allows a pallet to receive a workpiece and the workpiece to be clamped to the pallet while the pallet is in a horizontal position. Once the workpiece has been clamped to the pallet, the pallet may be re-oriented to a vertical position so that the pallet may be loaded into a machine tool that operates on a workpiece with the pallet in the vertical position. The pallet may also be rotated to an intermediate position, similar to an artist's easel, in which the pallet is held in an inclined position, between the horizontal and vertical positions.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows a machine tool generally designated by the reference numeral10. The machine tool is surrounded by standard guarding12, and an operator station14is positioned outside of the guarding. The machine tool receives a pallet15from a pallet manipulator17that may be positioned adjacent to a pallet access opening18in the guarding. The pallet15is transferred from the pallet manipulator17to a pallet receiver19that is a part of the machine. The pallet receiver19is then driven to the working zone of the machine in front of the spindle and the working tool

The operator viewing station14is positioned to allow the operator to view the tool magazine23and the automatic tool changing mechanism24inside of the guarding from the operator station. The operator station includes a standard control panel25by means of which the operator can program and operate the machine10.

FIG. 2shows the X, Y, and Z-axis elements of the machine tool. A pallet15with a workpiece16is positioned in front of a spindle or multi-axis head27that carries the working tool28and this establishes a workzone. The Y-axis column30is fixed and is bifurcated. The Y-axis column30carries a vertically movable saddle31that is mounted on vertical linear guides or ways. A servomotor32is mounted on each side of the Y-axis column30, and each servomotor32is coupled to a drive screw33. The drive screws33engage drive nuts34on opposite sides of the saddle31, and the servomotors32are used to raise and lower the saddle to the desired vertical position.

The vertically movable saddle31carries a Z-axis slide36. A Z-axis drive assembly37comprises a servomotor38and a drive screw39that are mounted on the Z-axis saddle31. The Z-axis drive assembly37may be selectively controlled to position the Z-axis slide36and the working tool28in the desired position along the Z-axis.

An X-axis frame member40supports a plurality of X-axis rails41. The pallet receiver19is mounted on the X-axis rails41for horizontal movement along the X-axis. The pallet receiver carries a vertically mounted pallet15on which a workpiece16may be mounted. One or more X-axis drive motors42shown in phantom are mounted on the X-axis frame member40to drive the pallet receiver back and forth along the X-axis rails41. The X-axis frame member40is coupled to the Y-axis column30by upper and lower tubular frame members45and46respectively.

FIGS. 3-5show the pallet loader and manipulator17. The pallet loader comprises a lower generally rectangular horizontal base portion50that includes two rear extending outrigger portions51. A vertical support portion52is mounted on each base portion50, and hypotenuse braces53connect the top of the vertical support portion52to the ends of the two rear extending outrigger portions51.

Roller tracks56are mounted on either side of the pallet loader17. The roller tracks in the preferred configuration include a horizontal portion57, a vertical portion58, and a radius portion59joining the bottom of the vertical portion58to the horizontal portion57. A pallet carriage60comprising a pallet support plate61and rollers62rides on the roller tracks56. The pallet support plate61is configured to receive and temporarily clamp a pallet15that is placed thereon. Standard clamping expedients such as mechanical, hydraulic, or electromechanical clamping devices may be used to clamp the pallet to the pallet support plate61.

As shown onFIGS. 3B and 3C, a positive locating assembly such as a shotpin67is mounted on the vertical support portion52of the pallet manipulator17. The shotpin67is configured to engage two or more shotpin receivers63and64on the pallet carriage60, as more fully described below. The shotpin may comprise a pneumatically actuated pin or slide, but other mechanisms may be used.

The preferred configuration of the load stand utilizes a chain65driven by a motor66to move the pallet carriage60and a pallet15between the horizontal and vertical position, but other drives can be used. In the preferred configuration, a chain65is provided on each side of the pallet loader, and a motor66to drive the chains is mounted on the top of each vertical support portion58. A pallet drive motor68may be provided on the bottom of the pallet carriage60. The pallet drive motor68may be used to rotate a drive element such as a helical screw or other traction device that is used to drive the pallet15off of the pallet carriage and onto the pallet receiver of a machine tool. The helical screw may engage cam followers (not shown) that are mounted on the bottom of the pallet, although other drive arrangements for the pallet15may be provided.

The load stand17allows the pallet to be rotated from a horizontal position as shown inFIG. 3Afor workpiece loading and clamping to a vertical position as shown inFIG. 4Afor loading the pallet15with the workpiece16into the machine. The load stand itself may be mounted on casters or rails allowing it be loaded at a station remote from the machine and then moved into position adjacent the machine so that the pallet can be transferred from the load stand into the machine.

The load stand17may also be provided with a second stop position to position the pallet support plate and the pallet in an inclined position at an angle of between 10 and 20 degrees from the vertical as shown inFIG. 5A. This allows the advantage of access to the workpiece16that is provided by a vertical pallet15while allowing the weight of the workpiece to be supported by the horizontal portion57of the roller track similar to the support that is given to a canvas on an artist's easel.

The shotpin67or other positive locating assembly comprises a failsafe locking device that may be utilized to lock the pallet carriage60in either the inclined position or the vertical position to ensure the pallet does not drop in the event of drive loss from the chain drive motor66. A first shotpin receiver63is mounted on the pallet carriage60to receive the shotpin67when the pallet carriage is in the inclined position as shown inFIGS. 5A and 5B. A second shotpin receiver64is mounted on the pallet carriage60to receive the shotpin67when the pallet carriage is in the vertical position as shown inFIGS. 4A and 4B. The engagement of the shotpin67with either of the shotpin receivers63and64as shown inFIGS. 4B and 5Bwill positively locate the pallet carriage60in either the vertical or inclined positions on the pallet loader17, and will prevent movement of the pallet carriage until the shotpin is withdrawn from the shotpin receiver. Thus, the shotpin receivers63and63comprise positive locating assemblies and positive stops for the pallet carriage60.

Having thus described the invention, various alterations and modifications may be apparent to those skilled in the art, which modifications and alterations are to be considered to be within the scope of the invention as defined by the appended claims.