Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D43/00—Feeding, positioning or storing devices combined with, or arranged in, or specially adapted for use in connection with, apparatus for working or processing sheet metal, metal tubes or metal profiles; Associations therewith of cutting devices
  • B21D43/02—Advancing work in relation to the stroke of the die or tool
  • B21D43/04—Advancing work in relation to the stroke of the die or tool by means in mechanical engagement with the work
  • B21D43/05—Advancing work in relation to the stroke of the die or tool by means in mechanical engagement with the work specially adapted for multi-stage presses
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D43/00—Feeding, positioning or storing devices combined with, or arranged in, or specially adapted for use in connection with, apparatus for working or processing sheet metal, metal tubes or metal profiles; Associations therewith of cutting devices
  • B21D43/02—Advancing work in relation to the stroke of the die or tool
  • B21D43/04—Advancing work in relation to the stroke of the die or tool by means in mechanical engagement with the work
  • B21D43/05—Advancing work in relation to the stroke of the die or tool by means in mechanical engagement with the work specially adapted for multi-stage presses
  • B21D43/055—Devices comprising a pair of longitudinally and laterally movable parallel transfer bars

Definitions

• This invention relates generally to production systems wherein workpieces are transferred through a series of equally spaced, linearly aligned work stations which perform a predetermined sequence of operations on the workpieces and, more particularly, to such a system for automatically transferring the workpieces from one work station to an adjacent work station within the system.
• One system for performing repetitive workpiece transfer and multiple realignment is a type of walking- beam system which provides transfer rails extending along both sides of a linear axis (x axis) through the work stations upon which the workpieces ride between each
• each of the rails is designed for movement along
• the finger grippers have associated actuators which permit them to move laterally (along the Y axis) , toward and away from the
• this design permits the finger grippers to first engage the workpiece by operation of its actuator, then raise the workpiece to the transfer level by actuation of the transfer rails, linearly move the workpiece to the
• standard transfer presses typically have standardized rail positions and permit only two or three different spacings between the rails in the lifted position.
• Standard transfer presses also have only a limited number of settings along the x-axis and no adjustment of distance of travel in either the up-down or back-forth directions. To exacerbate this problem, the standardized settings are peculiar to each manufacturer and not standardized industry wide. Hence, it would be virtually impossible for one shop to have transfer presses capable of testing or running the many possible combinations of available settings from various press manufacturers.
• a further problem with standard transfer presses is the lack of provision for easy removal of the rails for access for purposes of changing the dies.
• the transfer rails must be longer than the distance between the columns of the press since they also serve to load the workpiece into the press and unload it therefrom. Therefore, elaborate coupling mechanisms are necessary to allow removal of a portion of the rail when the tooling is removed. Die change capability is, therefore, an expensive option and permits rail change or removal only with great difficulty.
• Patent 4,621,526 to Schafer et al discloses a system wherein the transfer rail does not travel in the linear direction from one station to another. Rather, a secondary rail is mounted thereon and the finger units are in turn mounted on the secondary rail.
• the secondary rail is designed for reciprocal movement along the X axis between adjacent work spaces. This movement is actuated by a servomotor supported on the secondary rail.
• the finger units themselves are designed for lateral movement toward and away from the workpiece and are actuated by additional servomotors.
• lift columns are provided upon which the transfer rail is mounted. These lift columns are also actuated by electric servomotors.
• the finger units may be disposed on the rails in relation to the workpiece during die building and tryout, when a transfer press is typically not available.
• Such a system should also allow greater accessibility to the dies during maintenance and repair by containing the actuator system for the transfer mechanism in separate modules which may be removed, leaving the rails in proper position in relation to the workpiece.
• modules may be manufactured in a limited number of sizes and can be used with presses of a variety of sizes and of various configurations, regardless of the direction of feed or of the press design.
• the present invention provides a modular system particularly useful for transferring work pieces along a series of equally spaced, aligned work stations. While the preferred embodiment of the invention is used with a transfer feed press, the system is useful for transferring workpieces in any system having a series of equally spaced work stations aligned linearly along an axis whereon a predetermined sequence of operations is performed on the workpieces.
• a pair of spaced and parallel transfer rails extend longitudinally along both sides of the aligned work stations.
• the pair of rails is side mounted in order to allow access to the press.
• the workpiece engaging mechanism comprises horizontally extended fingers which are adapted to lift the workpiece from underneath. With the horizontally extending finger type of workpiece engaging mechanism which lifts the workpieces up, two parallel transfer rails and associated finger operator rails are provided which lift the workpieces on both sides.
• Such a system is suitable for transferring relatively large and heavy workpieces such as are commonly subject to stamping operations in a transfer press.
• Individually controllable means are provided for imparting reciprocal linear motion to the finger operator rails along the direction of travel of the workpieces as they pass through the series of aligned work stations.
• the finger operator rail is slidably mounted on the transfer rail.
• At least one actuator unit is provided which is supported independently from the transfer rail and is disposed at a location displaced laterally therefrom on a side thereof opposite the work stations. If a pair of transfer rails are provided, then at least one pair of actuators will be provided, with one disposed beside each transfer rail.
• Each actuator unit has a laterally extending arm or carriage which supports the transfer rail and is adapted to impart both lateral and up and down motion thereto.
• the lateral motion is along the Y axis in a direction corresponding to movement of the finger operators into and out of engagement with the workpieces.
• the up and down motion is along the Z axis and corresponds to movement of the finger operators for raising and lowering the workpieces.
• the actuator unit comprises a dual axis hydraulic actuator operating the arm in the Y and Z axes to engage and lift a workpiece, then lower and retract once the workpiece has been translated to the next work station by the finger operator rail.
• the hydraulic actuator comprises a pair of hydraulic fluid cylinders connected in parallel to a single fluid source driven by an independent motor. As the source outputs fluid, the arm will first be moved along the axis providing the least resistance until the arm reaches a stop. The arm then begins movement along the second axis, since that axis then provides the least resistance to movement. In this manner, the actuator unit automatically achieves sequencing of its driving forces without the need for additional timing apparatus.
• the actuator unit and its motor are supported independently of and remains stationary with respect to the motion of the transfer rail.
• the actuator units comprise modular units which may easily be moved into and out of operating relationship with the transfer rails.
• the transfer system of the instant invention possesses the advantages of providing movement of the finger operators in all three directions necessary to effect transfer of the workpieces and realignment thereof.
• none of the actuators or motors which provide movement in the three directions are disposed on the transfer or finger operator rail itself.
• the transfer rail may be made smaller and lighter.
• the actuator units are independently supported from the transfer rail, resulting in an efficient, modular system.
• the transfer system further comprises at least one sensor means for detecting the state of operation of the associated production system for purposes of synchronizing the operation of the transfer mechanism to the system.
• a sensor means will be mounted on the press ram in order to sense the position of the ram during each stroke of the press.
• the sensor is operatively connected to a means for centrally controlling movement of the transfer rail and finger operator rail to synchronize travel of the workpieces through the successive work stations in timed relation with performance of the sequence of operations.
• a linear actuator for imparting reciprocal motion to the finger operator rail is associated to move with, but supported independently from, the transfer rail.
• a motor for powering the linear actuator is supported independently of the transfer rail and remains stationary with respect to the movement of the transfer rail.
• the linear actuator is a belt drive system supported independently from the transfer rail and associated to move therewith and supplies the reciprocal motion to the finger operator rail .
• the belt drive system is powered by an independent motor which remains stationary during the operation of the transfer and finger operator rails.
• the belt drive system essentially comprises a belt mounted with the transfer rail for reciprocal rotation in the direction of travel of the workpieces.
• the belt is driven by a transverse spline shaft which can move with the lateral displacement of the transfer rail toward the workstations.
• the transverse spline shaf is driven by a vertical spline shaft marked for vertical movement with the transfer rail when a workpiece is lifted.
• the vertical spline shaft is powered by an independent motor which remains stationary with respect to the transfer and finger operator rails.
• the actuator units and motors for the transfer and finger operator rails are mounted on the crown of the transfer press itself to provide unobstructed access to the dies and work stations.
• each side is preferably mechanically independent of the other, but electronically synchronized to the press ram sensor. In this manner, both of the transfer rails and the finger operator rails function independently but cooperatingly to transfer workpieces between work stations.
• FIGURE 1 is a perspective view of the transfer system of the instant invention installed in a transfer press;
• FIGURE 2 is a perspective view of the transfer system of FIGURE 1 shown apart from the transfer press;
• FIGURE 2a is a perspective view of a single transfer system according to the present invention.
• FIGURE 2b is a partial section plan view of the transfer system of FIGURE 2a;
• FIGURE 3 is a perspective view of a motor and drive belt system associated with a transfer system according to the present invention for reciprocal actuation of a finger operator rail;
• FIGURES 4 and 5 are section views along lines 4-4, 4a- 4a and 5-5 in FIGURE 2b showing details of the connection of a reciprocal drive belt to a finger operator rail;
• FIGURE 6 is a section view along lines 6-6 showing details of a dual axis hydraulic actuator according to the present invention
• FIGURES 7 and 8 are side views of the actuator of FIGURE 6 showing the motion imparted by the actuator to a transfer rail;
• FIGURE 9 is a schematic diagram of the motor and hydraulic actuating system for the actuator of FIGURE 6;
• FIGURE 10 is a plan view of the outer structure of the hydraulic actuating system of FIGURE 9;
• FIGURE 11 is a side view of the motor for actuating the hydraulic actuating system of FIGURE 9;
• FIGURE 12 is a partial section end view of opposed actuator units according to the present invention engaging and lifting a workpiece from a transfer press work station; and
• FIGURE 13 is a perspective view of a transfer system according to the present invention adapted to be mounted from the overhead stationary crown of a press.
• FIGURES 1 and 2 there is shown a workpiece transfer system generally designated as 10 installed in a transfer press generally designated as 12.
• Transfer press 12 has a plurality of work stations 14 wherein a series of stamping operations are performed on a succession of workpieces W.
• a ram 16 supports a plurality of upper die halves 20a and each stroke of ram 16 causes the workpieces W to be stamped between an upper die 20a and an associated lower die 20b to form the workpieces W.
• the lower dies 20b are mounted on bolsters 22 and the upper dies 20a are mounted on the ram 16.
• the upper stationary part of the transfer press 12 is referred to as the crown 18.
• Transfer system 10 comprises a transfer rail 24 disposed laterally outboard of work station 14 and dies 20, running essentially parallel thereto. Mounted on each of the pair of transfer rails 24 is a finger operator rail 26 laterally inboard of transfer rail 24 adjacent work stations 14. Mounted in turn on the finger operator rails 26 are a plurality of fingers 28 which extend laterally toward the workpieces W. Each of the plurality of fingers 28 terminates in a workpiece engaging section 30.
• each of the workpiece engaging sections 30 provides a resting place for a corner of each of the plurality of workpieces W as they are successively transferred from one adjacent work station 14 to another work station 14. It is to be understood that the plurality of workpiece transfer mechanisms 30 may take a variety of other conventional designs and configurations, such as, for example, grasping fingers.
• the plurality of finger operators 28 are equally spaced longitudinally along the transfer rail 24. In the case of the workpieces W shown in the drawing, the finger operators 28 are arrayed in pairs so that the workpiece transfer mechanisms 30 may support each corner of a workpiece W. The spacing between adjacent pairs of finger operators 28 corresponds to the spacing between adjacent work stations.
• Finger operator rail 26 is slidably mounted on raceway 25 of transfer rail 24 in order to permit reciprocal, linear motion of the finger operator rail 26 with respect to transfer rail 24 along the X-axis, i.e. the direction of travel of workpieces W down the line of work stations 14.
• Such reciprocal, linear movement of finger operator rail 26 is created by means of a belt 56 mounted within housing 52 on transfer rail 24 and powered by a belt drive system generally shown in FIGURE 3. When powered by appropriately controlled electrical current, the belt drive system and belt will provide reciprocal linear motion of rail 26 with respect to rail 24.
• the linear reciprocal movement of finger operator rail 26 along transfer rail 24 causes the finger units 28 also to move reciprocally in a linear direction along the X axis as is shown by the arrow in FIGURE 2.
• at least one actuator unit 30 is provided generally shown at FIGURE 6.
• Actuator unit 30 is supported independently of transfer rail 24.
• actuator unit 30 is floor mounted by means of a longitudinal support frame 32 running parallel along-side the transfer press.
• Actuator unit 30 could, alternatively, be mounted on or within its own modular housing equipped, for example, with rollers or casters to permit the actuator unit to be easily moved into and out of operating relationship with the transfer press.
• Actuator unit 30 includes a laterally extending arm or transfer carriage 34 which extends toward the direction of the workpiece and which supports transfer rail 24.
• a pair of actuator units 30 and associated transfer carriages 34 are provided in order to adequately support the transfer rail 24. It is contemplated that at least one actuator unit 30 will be needed for each transfer rail 24, and typically, at least one pair of actuator units 30 will be needed to support each transfer rail 24.
• the belt drive system is powered by a reciprocal rotary motor 36 connected by belt 38 to a drive wheel 40 slidably engaging vertical spline shaft 42. Reciprocal rotary motion given to spline shaft 42 by motor 36 is transferred via gear box 44, belt 44 and drive wheels 48 to transverse spline shaft 50. Transverse spline shaft 50 is connected through the wall of housing 52 on transfer rail 24 to a drive wheel 54 positioned therein as shown in FIGURE 5.
• Drive wheel 54 has an unpowered counterpart longitudinally spaced therefrom in housing 52 and a drive belt 56 is mounted between the two wheels. It can be seen that reciprocal rotary motion of motor 36 will be transferred through the drive belt system to the drive belt mounted in housing 52 on transfer rail 24.
• finger operator rail 26 is shown slidably mounted laterally inward of transfer rail 24 along the Y-axis by way of bearing blocks 58 having a plurality of bearings or rollers 60 engaging raceway block 25 mounted on transfer rail 24.
• a support bracket arm 62 fastened to a portion of drive belt 56 by suitable mounting structure 64 extends over and across transfer rail 24 and is fixedly attached to finger operator rail 26.
• bracket arm 62 connected to the drive belt will reciprocate finger operator rail 26 with respect to the transfer rail in the direction of motion of the drive belt, i.e. along the X-axis.
• the drive belt system motor apparatus comprising motor 36, drive wheel 40, and belt 38 are supported on surface 33 of longitudinal support 32 independently of and stationary with respect to the transfer rail.
• Vertical spline shaft 42, gear box 44, belt and wheels 46 and 48 and transverse spline shaft 50 comprising the drive belt system are connected through system housing 49 to a carriage support 68 of transfer carriage 34 on actuator 30 for movement therewith along the Z-axis.
• transverse spline shaft 50 mounted to slide within upper drive wheel 48 and connected by link assembly 51, connected to the drive belt in housing 52 will be pulled along therewith due to its sliding engagement with upper geared wheel 48.
• the transfer rail is lifted by actuator unit 30 along the Z-axis, for example to lift an engaged workpiece from a work station, the drive belt system will be lifted therewith by the actuator unit as vertical spline shaft 42 slides through drive wheel 40.
• a transfer carriage 34 supporting transfer rail 24 is slidably mounted along the Y-axis to a carriage support 68, which in turn is slidable along the Z- axis with respect to the base 70 of the actuator unit.
• the actuator unit comprises a dual axis actuator for driving each workpiece transferring unit and essentially consists of a lifting fluid cylinder 72 and a translating fluid cylinder 74.
• the lifting fluid cylinder is attached to the actuator unit base and its cylinder rod 73 is connected to the carriage support.
• the translating fluid cylinder is attached to the carriage support and its cylinder rod 75 is connected to the transfer carriage.
• transfer carriage 34 By extending rod 75 of the translating fluid cylinder 74, transfer carriage 34 is moved in the Y direction with respect to support 68.
• the solid lines of FIGURE 7 show the transfer carriage 30 in the workpiece engaging position, with the retracted position shown in phantom.
• the action of the lifting fluid cylinder 72 and its rod 73 in moving the transfer carriage 34 and carriage support 68 in the Z direction is shown in FIGURE 3.
• the solid lines show transfer carriage 34 in its highest, workpiece lifting position with the lower position shown in phantom. Movement of the transfer carriage 34 in the Y and Z directions causes the transfer rail 24, finger operator rail 26, and the plurality of fingers 28 to move correspondingly.
• FIGURE 9 Schematically shown in FIGURE 9 are the lifting fluid cylinders 72 and translating fluid cylinders 74 for driving two different actuator units described previously. Also shown is a source fluid cylinder 76 with cylinder rod 77 attached to a rack 78 and pinion gear 80. A rotary motor 82 operating through a rack 78 and pinion gear 80 provides reciprocal motion to cylinder rod 77 of source fluid cylinder 76. Source fluid cylinder 76, motor 82 and the rack and pinion connecting the two are shown in detail in FIGURES 10-12. In the illustrated embodiment, the structure of FIGURES 10-11 is mounted to longitudinal support 32 adjacent the floor as shown in FIGURE 2a.
• the lifting fluid cylinder 72 and translating fluid cylinder 74 have fluid ports A and B disposed on opposite sides of their pistons 71 each of which are connected to similarly denoted ports on each side of source cylinder 76.
• the weight of transfer rails 24, finger operator rails 26, fingers 28, and associated workpieces W assist in the retraction of the rods 73 of the lift cylinders 72. Because there is less resistance to the movement, the rods 73 of lifting cylinders 72 retract first, followed by the retraction of the rods 75 of the translating cylinders 74. Thus, the transferring mechanism lowers the workpieces W and then retracts the fingers 28.
• a single source cylinder 76 is used to supply fluid to all sets of lifting fluid cylinders 72 and translating fluid cylinders 74 located in the different actuator units 30. This results in an automatic synchronization of all actuator units of the transfer press without gears, cams, complicated mechanical timing devices, or complex electronic servomechanisms.
• a series of smaller diameter source cylinders can be used, each one driving a transferring fluid cylinder and a lifting fluid cylinder 78. Synchronization can be achieved by simultaneously driving all source cylinder rods 52 with rack 56.
• all fluid cylinders are single rod ended.
• all single rod ended fluid cylinders can be replaced with double rod ended cylinders which have rods extending out of each cylinder end.
• Such single and double ended rod cylinders are commercially available and well known to those skilled in the art.
• the herein workpiece transfer system permits the plurality of workpieces W to be moved along all three axes of movement. The movement of a single workpiece W during a typical cycle of transfer press 12 will now be described. In order to permit the workpiece W to be loaded onto the transfer press, typically the pair of finger operator rails 26 are made longer than the rest of the system.
• the ram 16 will then be operated to cause stamping of the workpiece W between die pieces 20a and 20b. After completion of its stroke, ram 16 will lift.
• the belt drive system may reciprocate finger operator rail 26 along the X axis in an opposite direction, thus causing a new set of finger operators 28 to be in position for engagement with workpiece W.
• Transfer carriage 34 will then move along the Y axis into its extended position, causing engagement of finger operators 28 with the workpiece W.
• Lift cylinder 72 will move rod 73 along the Z axis into its extended position to lift the workpiece back into the position shown in FIGURE 12.
• the belt drive system After engagement of finger operators 28 with workpiece W and the lifting of the workpiece, as described above, the belt drive system will then displace workpiece W along the X axis for a sufficient distance to cause it to be aligned with the next work station 14. The cycle is then repeated. At each cycling of the transfer system 10, a plurality of workpieces are transferred between each adjacent work station 14. In order for a single workpiece W to travel through all of the plurality of work stations 14, it will be necessary for the system to cycle as many times as there are work stations 14.
• each transfer rail, and accordingly the plurality of actuators 30 and belt drive systems associated therewith be independently controllable.
• the independent control means (not shown) for each side of the transfer system is connected to a central controller 60, shown in FIGURE 1.
• Sensor means such as an absolute position transducer (not shown) are associated with the press ram in a well-known manner are used to sense the position of the rams 16.
• each mechanically independent side of system 10 may be electronically coordinated so that transfer and alignment of the plurality of workpieces W is synchronized with one another and with the operation of transfer press 12. This can be accomplished by simultaneously actuating, in the proper sequence, the various motor means for the actuator units 30 and the drive belt systems for each transfer system 10 on each side of the press. Since each transfer system 10 on each side of transfer press 12 is independently controllable, the system 10 may be used to realign and reposition the plurality of workpieces W as required by each stamping operation. For example, the right member of an opposed pair of finger operator rails 26 may be made to move at a faster rate than the left member. Such movement would cause the workpiece W to rotate somewhat. Similarly, movement of the actuator units 30 may be varied as necessary to adjust to required operating conditions. As shown in the preferred embodiment, actuator units
• the actuator units 30 are dual axis hydraulic actuators as described above. Again however the invention contemplated herein is not limited to this type of actuator, but may include other suitable means of imparting linear motion. It may be seen how the therein system is adaptable for operation with a wide variety of different transfer press designs of varying sizes. Thus, in an installation having transfer presses of various types, it is possible to move the operating system 10 from one transfer press to another.
• the transfer system is modular, and as many components may be added as are necessary to accommodate the size of the press and the number of work stations therein.
• the actuator units 30 may be used with existing systems having die mounted transfer rails which utilize a cross slide bracket. Hence, retrofitting of existing systems is inexpensive and easy.
• the actuators, motors and drives of the present system are deployed outboard of the press itself and supported independently from the transfer and finger operator rails, thus resulting in easier operation, as well as in a reduction of the bulk of the rail necessary to support the system.
• the transfer system of the present invention is mounted or depends from the upper stationary press crown shown in FIGURE 1 via a support frame 29.
• This transfer system arrangement functions in the same manner as previously described, but greatly increases available floor space adjacent the transfer press and provides unobstructed access thereto.
• support frame 29 may take various forms, and the dimensions of the actuator units may vary to accommodate such overhead mounting.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Press Drives And Press Lines (AREA)
• Specific Conveyance Elements (AREA)
• Manipulator (AREA)
• Multi-Process Working Machines And Systems (AREA)
• General Factory Administration (AREA)

Priority Applications (1)

Applications Claiming Priority (6)

Publications (3)

Family

ID=27395488

Family Applications (1)

Country Status (9)

Families Citing this family (6)

Family Cites Families (10)

• 1989
  • 1989-06-22 CA CA000603693A patent/CA1311438C/en not_active Expired - Lifetime
  • 1989-06-22 IL IL90716A patent/IL90716A0/xx unknown
  • 1989-06-23 WO PCT/US1989/002771 patent/WO1990000099A1/en active IP Right Grant
  • 1989-06-23 DE DE89908117T patent/DE68908562T2/de not_active Expired - Fee Related
  • 1989-06-23 ES ES8902222A patent/ES2016894A6/es not_active Expired - Lifetime
  • 1989-06-23 KR KR1019900700418A patent/KR0143896B1/ko not_active IP Right Cessation
  • 1989-06-23 AU AU39634/89A patent/AU3963489A/en not_active Abandoned
  • 1989-06-23 EP EP89908117A patent/EP0426707B1/de not_active Expired - Lifetime
  • 1989-06-23 JP JP1507648A patent/JP2708918B2/ja not_active Expired - Fee Related

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events