FIELD OF THE INVENTION

The present invention relates to an automatic exchanging device of a cross member of a transfer feeder and a control system therefor.

BACKGROUND OF THE INVENTION

Conventionally, a transfer feeder employing a vacuum transporting system, includes a plurality of cross bars transversely arranged between a pair of transfer feeders which are arranged in parallel relationship with respect to a workpiece transporting direction. For each of these cross members, work drawing means, such as a vacuum cup, is provided for drawing the workpiece, as an attachment.

The above-mentioned workpiece drawing means should be differentiated in size or so forth depending upon the workpiece to be transported. Therefore, in the prior art, the cross bar is removed out of a press machine upon changing a die for exchanging the workpiece drawing means mounted on the cross bar in external preparation or for exchanging the workpiece drawing means together with the cross bar.

However, the conventional exchanging operation has been performed by manual work of the worker to take long period and thus to be inefficient. Furthermore it is possible to cause damaging caused by interference with the die due to error in mounting or adjustment.

SUMMARY OF THE INVENTION

In view of the above-mentioned circumstance, the present invention has been worked out for improving the above-mentioned defects. Therefore, it is an object of the present invention to provide an automatic exchanging device of a cross bar of a transfer feeder and a control system therefor, which makes it possible to perform automatic exchanging of the cross bar.

In order to accomplish the above-mentioned object, a cross bar automatic exchanging device of a transfer feeder, according to the first aspect of the present invention, comprises:

   a cross bar exchanging robot for exchanging cross bars removed from a press body with cross bars to be used for the next time via a moving bolster, together with die to be exchanged; and

   a cross bar storage rack for storing necessary number of cross bars for press processes.

Also, in order to accomplish the above-mentioned object, a control system for a cross bar automatic exchanging device, in accordance with the second aspect of the invention, in which cross bars removed from a press body via a moving bolster together with a die to be exchanged are stored in a cross bar storage rack by a cross bar exchanging robot, and subsequently cross bars adapted to a die to be used in the next operation is set on the moving bolster by the cross bar exchanging robot, comprising:

   a die discrimination device for discriminating die identification indication provided for respective of a plurality of dies and selecting one of the dies to be used in the next operation;

   a cross bar discrimination device for discriminating cross bars adapted to the die to be used in the next operation among a plurality of cross bars respectively provided identification indications;

   a cross bar exchanging robot control device for controlling the cross bar exchanging robot for taking out the discriminated cross bars from the cross bar storage rack;

   a memory device for storing storage positions for respective of a plurality of cross bars stored in the cross bar storage rack; and

   a memory device for storing vacant storage positions in the cross bar storage rack.

With the cross bar exchanging device according to the present invention, the cross bars removed from the press body via the moving bolster together with the used die are taken out by the cross bar exchanging robot and stored in the cross bar storage rack, and the cross bars to be used in the next operation is taken out from the cross bar storage rack and set on the moving bolster. Therefore, the cross bar exchanging operation can be performed automatically and unattendantly.

By this, since the exchanging of the cross bars can be efficiently performed in short exchanging operation period, it may contribute for shortening of a die exchanging period and for improvement of productivity. Also, since error in mounting or adjustment will never be caused, a problem to cause damaging of the die can be solved.

On the other hand, with the control system for the cross bar automatic exchanging device, the used die removed from the transfer press via the moving bolster is discriminated, and the cross bars removed are carried by the cross bar exchanging robot so that they may be stored in vacant storage positions in the cross bar storage rack, and the cross bars taken out from the cross bar storage rack is set on the cross bar receptacle base by means of the robot. Thus, since the die and the cross bars are exchanged after identification, exchanging with the cross bars not adapted to the die can be successfully avoided to prevent the die from being damaged. Furthermore, since the vacant positions in the cross bar storage rack are preliminarily stored, the cross bar exchanging robot can be operated in the minimum distance during storing operation. As a result of this, the exchanging operation for a plurality of cross bars can be made efficient.

The objects, aspects and advantages of the present invention will become apparent to those skilled in the art from the preferred embodiment consistent with the principle of the invention as described and illustrated on the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

• Fig. 1 is a perspective view of a general overview of a transfer press machine employing a cross bar automatic exchanging device as one embodiment of the present invention;
• Fig. 2 is a fragmentary plan view of the transfer press shown in Fig. 1;
• Fig. 3A is a front elevation of a cross member receptacle base;
• Fig. 3B is a front elevation of a cross bar storage rack;
• Figs. 4, 5 and 6 are respectively fragmentary front elevation, fragmentary side elevation and fragmentary plan view of the cross bar automatic exchanging device;
• Fig. 7 is an illustration of the cross bar exchanging device as viewed in the direction of an arrow Z in Fig. 6;
• Fig. 8 is a section taken along line VIII - VIII of Fig. 7; and
• Fig. 9 is a block diagram showing one concrete example of a control system for controlling the cross bar control device of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment of the present invention will be discussed hereinafter in detail with reference to the accompanying drawings.

At first, across bar automatic exchanging device of the present invention will be discussed in terms of a concrete embodiment illustrated in Figs. 1 to 8.

Fig. 1 is a perspective of an overview of a transfer press and various facilities provided periphery thereof, Fig. 2 is a plan view of the same, Fig. 3A is a front elevation of a cross bar receptacle base, Fig. 3B is a front elevation of a cross bar storage rack, Figs. 4 to 6 show the cross bar automatic exchanging device.

In these figures, 1 denotes a press body, 2 denotes a cross bar automatic exchanging device provided at front and back sides of the press body 1, 3 denotes a die exchanging area defined at the upstream side of the press body 1 and 4 denotes an automatic palletizer provided at the downstream side of the press body 1.

The above-mentioned cross bar automatic exchanging device 2 comprises a cross bar exchanging robot 7 movable on a traveling rail 6 aerially extending in the transverse direction, and a cross bar storage rack 9 storing cross bars 8 to be used in press forming. In the drawings, 10 denotes a moving bolster extracted from the press body 1, on which dies 11 are mounted. At both sides of the die 11, cross bar receptacle bases 12 are extended from the upper surface of the moving bolster 10. On the cross bar receptacle bases 12, the cross bar 8 to be exchanged are mounted by removing from a transfer bar (not shown).

On the cross bar receptacle bases 12, locating pins 12a are extended so that the cross bar 8 is mounted with vertically orienting workpiece drawing means 13, such as vacuum cups mounted on the cross bar 8, by engaging pin holes 8a pierced at both end portions of the cross bar 8 with the locating pins 12a, as shown in Fig. 3.

On the other hand, the cross bar exchanging robot 7 has a moving carriage 15 traveling on the traveling rail 6, as shown in Fig. 6.

The traveling carriage 15 has a construction, in which rollers 16 rotating on the traveling rail 6 are provided on a transverse beam 15a. A traveling motor 17 and a lifting rod 18 are provided at the central portion of the transverse beam 15a.

Rotation of the traveling motor 17 is reduced by a reduction gear unit 19 and then transmitted to pinions 21 provided at both ends of the transverse beam 15a via drive shafts 20.

The pinions 21 mesh with racks 23 provided on the platform 22 supporting the traveling rail 6. According to rotation of the pinions 21, the traveling carriage 15 moves along the traveling rail 6.

On the other hand, the lifting rod 18 is supported on a support member 25 which is provided at the central portion of the transverse beam 15a, via linear guides 26 for vertical movement.

A lifting motor 27 is mounted on the support member 25. With this lifting motor 27, a pinion 29 is driven to rotate via a reduction gear unit 28.

The pinion 29 is meshed with a rack 30 attached on the lifting rod 18 so as to lift up and down the lifting rod 18. A chucking device 32 is mounted mon the lower end of the lifting rod 18. The chucking device 32 holds the cross bar 8, stores in the cross bar storage rack 9, and mounts the cross bar 8 in the cross bar storage rack 9 onto the cross bar receptacle base 12. As shown in Fig. 8, The chucking device 32 has a chucking cylinder 33 provided at the lower end of the lifting rod 18.

The tip end of a piston rod 33a extending downwardly from the chucking cylinder 33 is connected to a pin 35 supporting a chucking finger 34, via a link 36.

The base portion of the chucking finger 34 is supported at the lower end of the lifting rod 18 at by a pin 35 so that the tip end side is opened according to expansion of the piston rod 38a. Closing of respective chucking fibers 34 is performed by a return spring 37 wound around the piston rod 33a.

Next, discussion will be given for operation. The cross bar 8 to be exchanged is mounted on the cross bar receptacle base 12 of the moving bolster 10 and withdrawn frontwardly or rearwardly from the press body 1, together with the die 11, as shown in Fig. 1.

When the moving bolster 10 reaches the front side or rear side position of the press body 1, the cross bar exchanging robot 7 maintained in stand-by state thereabove moves above one of the cross bars 8 to be initially removed and lowers the lifting rod 18.

Then, the chucking device 32 at the lower end of the lifting rod 18 chucks the central portion of the cross bar 8, moves up to a storage height of the cross bar storage rack 9, and then moves into the cross bar storage rack 9 for storing the cross bar 8 in the storage position 9a in the cross bar storage rack 9.

It should be noted that the storage positions 9a are preliminarily given addresses so that the cross bar 8 stored in the storage position 9a is recorded by the address. By this, upon performing press operation for the same model number, necessary cross bar 8 can be accurately and quickly taken out.

On the other hand, for the cross bar 8, an identification number, such as model number, step number and so forth of the formed product is preliminarily provided in a form of a bar code or so forth. By reading the identification number by means of a reading device, such as a bar code reader or so forth provided on the chucking device 32, the bar code 8 to be exchanged can be checked at every occurrence to avoid error in selection of the cross bar 8.

When all of used cross bars 8 are stored in the cross bar storage rack 9 by repeating the foregoing operation, the cross bars 8 to be used in the next time are taken out of the storage positions 9a in the designated address in one-by-one basis and then set on the cross bar receptacle base 12 on the moving bolster 10 through the operation opposite to those set forth above.

Exchanging operation of the cross bar 8 is performed completely in automatic during operation of the press body 1. Once, the exchanging operation is completed, a stand-by state is maintained until the current press operation is finished.

When the press operation is finished, the used die 11 and the cross bars 8 are taken out of the press body 1 together with the moving bolster 10. Then, another moving bolster 10 held in the stand-by state is moved into the press body 1 for next press operation. It should be noted that when the period required for exchanging the cross bars becomes longer than a normal production period, a period to place the press in a waiting state is arisen.

In such case, as shown in Fig. 5, the exchanging period may be shortened for avoiding the waiting period of the press after completion of the press operation, by employing the automatic exchanging device, in which respectively two sets of the lifting devices 18 and the chucking device 32.

Next, discussion for a control system of the foregoing cross bar automatic exchanging device will be given in connection with Fig. 9.

For the die 11 mounted on the moving bolster 10 is provided with a die identification indication 45 in a form of bar code or so forth. On the other hand, the cross bar 8 is provided with a cross bar identification indication 46.

The die identification indication 45 is read by a die discrimination device 47 of the control system and input to a cross bar exchanging robot control system 48 and a storage rack memory device 49 which stores the address given for the cross bar storage position 9a. On the other hand, the cross bar identification indication 46 is read by a cross bar discrimination device 50 and input to the cross bar exchanging robot control system 48.

It should be noted that, in the drawings, the reference numeral 51 denotes an input device for inputting the address manually when the cross bar 8 is manually stored in the cross bar storage rack 9, 52 denotes a memory device storing vacant addresses of the storage position 9a and constituted by a sequencer or so forth.

Next, operation will be discussed. When the die 11 and the cross bar 8 are withdrawn frontwardly and rearwardly from the transfer press via the moving bolster 10 for exchanging the die after finishing the press operation, the die discrimination device 47 reads the die identification indication 45 provided on the die 11 and input the die data to the cross bar exchanging robot control system 48. By this, the cross bar exchanging robot control system 48 controls the cross bar exchanging robot 7 which is maintained in stand-by state at the upper side. Initially, the cross bar exchanging robot 7 is moved above the cross bar 8 to be first removed and grips the cross bar 8 on the cross bar receptacle base 12 by the chucking device 32 provided at the lower end of the lifting rod 18.

The cross bar identification indication 48 attached to the cross bar 8 is read by the cross bar discrimination device 50 provided on the chucking device 32 for confirmation that the cross bar 8 is adapted to the die 11. Thereafter, the cross bar exchanging robot control system 48 detects the vacant storage position 9a from the memory device 52 storing the vacant position in the storage rack, moves the cross bar exchanging robot 7 through a minimum moving distance, and stores the cross bar 8 in the vacant storage position 9a.

After finishing storing of the all cross bar 8 by subsequently repeating the above-mentioned operations, the moving bolster 10 is moved into the transfer press to complete exchanging of the die 11.

On the other hand, once the exchanging of the die 11 is completed and the preceding production die 11 is transferred into the cross bar automatic exchanging device 2, the die discrimination device 47 initially reads the die identification indication 45 provided on the die 11 and inputs the cross bar exchanging robot control system 48.

Once the cross bar exchanging robot control system 48 confirms that the introduced die 11 is consistent with the die to be used for the next time on the basis of the preliminarily input command, the cross bar storage position 9a storing the cross bar 8 adapted to the die 11 is read out from the memory device 49 to move the cross bar exchanging robot 7 through a minimum distance to take out the cross bar 8 stored in the storage position 9a to place on the cross bar receptacle base 12 on the moving bolster 10.

Thereafter, by repeating the above-mentioned operations for necessary times to complete transferring of all of the cross bars, initial position is re-established and held in stand-by state.

When the currently performed press operation is finished and the used die 11 is removed, the die 11 and the cross bar adapted thereto are introduced into the transfer press through the moving bolster 10. Then, the transfer bars are set on respective predetermined positions.