Work carrying device of pressing machine

A transfer feeder 41 has a lift/clamp device 80 moving a bar 14 in a lift direction and a clamp direction, a plurality of feed carriers 52 installed on the bar 14, and feeding linear motors 53 driving the feed carriers 52 in a feed direction. Since an object driven by the feeding linear motors 53 can be formed small since the feed carriers 52 are installed on the bar 14, the feeding linear motors 53 having a small capacity can be adopted to simplify the structure of a transfer press 1.

This application is a U.S. National Phase Application under 35 USC 371 of International Application PCT/JP2004/015739 filed Oct. 22, 2004.

TECHNICAL FIELD

The present invention relates to a work carrying device of pressing machine.

BACKGROUND ART

FIG. 27shows a transfer press100as a conventional pressing machine. As shown inFIG. 17, four uprights121are erected on a bed123located in a lower portion of a press frame110of the transfer press100, and a crown120is provided above the uprights121. A slide drive device is built into the crown120for driving a slide122disposed below the crown120upward and downward. Upper dies112are attached to a lower surface of the slide122. Lower dies113are attached to an upper surface of a moving bolster130opposed to the slide122, so that a work is press-formed by cooperation of the upper dies112with the lower dies113. A pair of transfer bars114,114are provided on the right and left with the upper dies112and the lower dies113sandwiched therebetween, the pair of bars114,114extending in parallel. The transfer bars114,114are provided with fingers (not shown) faced to each other for holding a work (not shown). By appropriately reciprocating the transfer bars114,114in a feed direction, a lift direction and a clamp direction, the work is sequentially transferred from the lower die113on an upstream side (the left side inFIG. 27) to the lower die113on a downstream side (the right side inFIG. 27). Incidentally, the feed direction means the direction in parallel with the work transfer direction, and motions in the feed direction include an advance motion (i.e., a motion from the upstream side toward the downstream side) and a return motion (a motion from the downstream side toward the upstream side). Further, the lift direction means vertical direction, and motions in the lift direction include a lift motion (i.e., a motion from the lower side to the upper side) and a down motion (i.e., a motion from the upper side to the lower side). Further, the clamp direction means a horizontal direction perpendicular to the feed direction (i.e., the direction vertical to the paper surface in theFIG. 27), and motions in the clamp direction include a clamp motion (i.e., a motion for decreasing the distance between two transfer bars114) and an unclamp motion (i.e., a motion for increasing the distance between two transfer bars114).

Further, in the case of a three-dimensional transfer feeder, by repeating clamp operation, lift operation, advance operation, down operation, unclamp operation and return operation to the transfer bar114, the work is sequentially transferred to the lower die113on the downstream side.

A feed drive section115for moving the transfer bar114in the feed direction is fixed on the lateral surface of the press frame110on the upstream side (or the downstream side). A clamp drive section116, which moves the transfer bar114in the clamp direction, and a lift drive section117, which moves the transfer bar114in the lift direction, are provided on the bed123between the two uprights121on the upstream side and the two uprights121on the downstream side.

The feed drive section115, the clamp drive section116, and the lift drive section117respectively rotate a feed cam, a clamp cam and a lift cam with the rotating power fetched from the press main body, so that the transfer bar114is driven by these cams to perform three-dimensional motion in the feed direction, the clamp direction, and the lift direction.

However, in the case of the movements in the feed direction, the clamp direction, and the lift direction are driven by the respective cams, to obtain a variable motion pattern of the transfer bar114, plural cams are needed according to the motion pattern, therefore not only the drive mechanism becomes complicated and expensive, but also the variable motion pattern is limited by the number of the cams. Thus recently there is a desire to easily obtain various motion patterns with a simple drive mechanism.

Thus a work carrying device is proposed, of which the feed drive section115, the clamp drive section116, and the lift drive section117are driven by respective servomotors, and the servomotors are controllable.

The feed drive section115, the clamp drive sections116, and the lift drive section117, all these driving by means of servomotors, have the following configuration. The feed drive section115is provided with a ball screw mechanism, which uses a first servomotor as driving source, for reciprocating the transfer bar114in the feed direction. The clamp drive section116is provided with a ball screw mechanism, which uses a second servomotor as driving source, for reciprocating the transfer bar114in the clamp direction. The lift drive section117is provided with a rack and pinion mechanism, which uses a third servomotor as driving source, for reciprocating the transfer bar114in the lift direction.

Further, as described in Patent Document 1, all of the feed operation, the clamp operation, and the lift operation of the feed bar also can be driven by linear motors. In such a work carrying device, the feed bar is suspended from a bracket fixed to the press main body. The linear motor is provided between the bracket and the feed bar, and the feed bar moves in the feed direction relative to the bracket so as to perform the feed operation. Also, the clamp operation and the lift operation are driven by respective linear motors provided on the lower surface of the feed bar.

Further, Patent Document 2 describes a work carrying device in which a fixed bar is provided with a first bracket which is driven by a linear motor so as to perform lift operation, the first bracket is provided with a second bracket which is driven by a linear motor so as to perform clamp operation, and the second bracket is provided with a third bracket with a work holder installed thereon, the third bracket being driven by a linear motor so as to perform feed operation.

Further, Patent Document 3 describes a work carrying device having a pair of lift beams arranged in parallel in the work transfer direction and capable of being freely moved in the vertical direction, a carrier provided on each lift beam and capable of being moved in the longitudinal direction of the lift beam by means of a linear motor, sub-carriers provided on the carrier and capable of being moved along a guide of the carrier in the carrier moving direction by means of a linear motor; and a cross bar spanning over the pair of oppositely facing sub-carriers and having a work holder. In such a work carrying device, the lift operation is performed by moving the lift beams by means of a servomotor. Further, the feed operation is performed by moving the carrier and the sub-carriers in the feed direction by means of a linear motor. Owing to the carrier and the sub-carriers, the moving range in the feed direction can be widened.

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

However, in the conventional transfer press as shown inFIG. 27, since the feed box with the feed drive section115housed therein is arranged on a lateral surface of the press main body, and since a lift box and a clamp box, respectively having the lift drive section117and the clamp drive section116housed therein, are arranged between the right and left uprights121, not only the drive mechanism becomes complicated, but also the manufacturing cost is increased.

Further, since the feed box with the feed drive section115housed therein projects outwardly from the lateral surface of the press main body, not only it can be obstructive in the case where a material supply device or a work carrying-out device is wanted to be installed, but also a wide installation space is required for press line.

Further, with the art described in Patent Document 1, since the feed bar in its entirety is driven in the feed direction, the total weight to be driven becomes large. Thus a driving source having larger capacity is necessary to follow the production speed of pressing, so that the manufacturing cost is increased.

Further, with the art described in Patent Document 2, since the second bracket is provided with a third bracket which performs feed operation driven by a linear motor, the length of the second bracket in the feed direction has to be large to ensure feed distance. Thus the second bracket becomes large and heavy, and the second bracket has to perform clamp operation relative to the first bracket. Further, the first bracket, which holds the second bracket, has to perform lift operation relative to the fixed bar. Thus linear motors having larger capacity will necessarily be used for the driving mechanism for performing clamp operation and lift operation, so that the manufacturing cost is increased.

Further, with the art described in Patent Document 3, though the moving range in the feed direction can be widened, a carrier capable of being moved by a linear motor and sub-carriers capable of being moved by a linear motor will be necessary. Thus the number of the linear motor for feeding the work is increased, therefore not only the construction becomes complicated, but also the manufacturing cost is increased.

As according to the above, though the servomotor or other methods are employed, the effect for simplifying the construction is not enough, simplified construction and reduced cost are further desired.

In view of the aforementioned problems, it is an object of the present invention to provide a work carrying device of pressing machine having simple structure.

Means for Solving the Problems

In order to solve the aforementioned problems, according to a first aspect of the present invention, it is provided a work carrying device of pressing machine which includes: frames provided on both sides of a moving bolster in a work transfer direction; a pair of bars provided in parallel in the work transfer direction; a feed carrier held by each of the bars; a feed drive mechanism provided on each of the bars, the feed drive mechanism driving the feed carrier in the work transfer direction; a lift drive mechanism provided in each of the frames, the lift drive mechanism driving the pair of bars in a lift direction so that the bars moves vertically; a clamp drive mechanism provided in each of the frames, the clamp drive mechanism driving the pair of bars in a clamp direction perpendicular to the work transfer direction; and a work holder detachably attached to the feed carrier for holding a work.

According to a second aspect of the present invention, in the work carrying device of pressing machine according to the first aspect of the present invention, the feed drive mechanism is provided with a linear motor.

According to a third aspect of the present invention, in the work carrying device of pressing machine according to the first aspect of the present invention, the feed drive mechanism is provided with a servomotor.

According to a fourth aspect of the present invention, in the work carrying device of pressing machine according to any one of the first to third aspects of the present invention, a plurality of the work holders for plural working processes are detachably attached to the feed carrier.

According to a fifth aspect of the present invention, in the work carrying device of pressing machine according to any one of the first to fourth aspects of the present invention, the pair of bars include fixed bars supported by the lift drive mechanism or the clamp drive mechanism, and movable bars capable of being detached from the fixed bars.

According to a sixth aspect of the present invention, it is provided a work carrying device of pressing machine which includes: a pair of bars supported by frames provided on both sides of a moving bolster in a work transfer direction, the pair of bars being arranged in parallel in the work transfer direction; a feed carrier held by the bars; a feed drive mechanism provided on each of the bars, the feed drive mechanism driving the feed carrier in the work transfer direction; a base held by the feed carrier; a lift drive mechanism provided on the feed carrier, the lift drive mechanism driving the base in a lift direction so that the base moves vertically; and a work holder detachably attached to the base for holding a work.

According to a seventh aspect of the present invention, the work carrying device of pressing machine according to the sixth aspect of the present invention is further provided with a clamp drive mechanism provided on the feed carrier, the clamp drive mechanism driving the base in a clamp direction perpendicular to the work transfer direction.

According to an eighth aspect of the present invention, in the work carrying device of pressing machine according to the sixth or seventh aspect of the present invention, at least one of the feed drive mechanism and the lift drive mechanism is provided with a linear motor.

According to a ninth aspect of the present invention, in the work carrying device of pressing machine according to the seventh aspect of the present invention, the clamp drive mechanism is provided with a linear motor.

According to a tenth aspect of the present invention, in the work carrying device of pressing machine according to the sixth or seventh aspect of the present invention, at least one of the feed drive mechanism and the lift drive mechanism is provided with a servomotor.

According to an eleventh aspect of the present invention, in the work carrying device of pressing machine according to the seventh aspect of the present invention, the clamp drive mechanism is provided with a servomotor.

According to a twelfth aspect of the present invention, in the work carrying device of pressing machine according to any one of the sixth aspect to eleventh aspect of the present invention, a plurality of the work holders for plural working processes are detachably attached to the base.

According to a thirteenth aspect of the present invention, the work carrying device of pressing machine according to any one of the sixth to twelfth aspects of the present invention is further provided with a bar-interval adjusting device for adjusting an interval between the pair of bars.

According to a fourteenth aspect of the present invention, in the work carrying device of pressing machine according to any one of the sixth to thirteenth aspects of the present invention, the pair of bars can be detached from the frames.

According to a fifteenth aspect of the present invention, in the work carrying device of pressing machine according to any one of the first to fourteenth aspects of the present invention, a plurality of the feed carriers are held by each of the bars, a motion of the each feed carrier being individually controllable.

According to a sixteenth aspect of the present invention, in the work carrying device of pressing machine according to any one of the first to fourteenth aspects of the present invention, a plurality of the feed carriers are held by each of the bars, adjacent ones of the plurality of the feed carriers being connected to each other by a connector.

EFFECT OF THE INVENTION

According to the first aspect of the present invention, the pair of bars are respectively driven by the lift drive mechanism in the lift direction and driven by the clamp drive mechanism in the lift direction. Further, the feed carrier held by the bar is driven by the feed drive mechanism to move relative to the bar in the feed direction. By these operations, the work carrying device of pressing machine moves the work holder in three dimensions. The motion of the work holder in the feed direction (which requires a long stroke) is performed by the feed drive mechanism directly provided on the bar.

With such an arrangement, since the feed drive mechanism, which requires a long stroke, is provided on the bar, the feed drive mechanism can be compactly installed in the press main body.

Since a feed device (a feed box) projected from the press main body on the downstream side (or the upstream side) for moving a conventional bar itself in the feed direction is eliminated, the pressing machine as a whole can be downsized. Further, since the feed drive mechanism only needs to have a driving force necessary for driving the feed carrier, the feed drive mechanism with small capacity can be used. Thus the construction of the work carrying device can be simplified.

Herein, the feed direction means a direction parallel to the work transfer direction, the lift direction means a direction perpendicular to a plane including the pair of the bars, and the clamp direction means a horizontal direction perpendicular to the work transfer direction, namely a direction in which the pair of bars move toward or away from each other.

Note that the case of installing the feed drive mechanism on the bar not only includes the case where the feed drive mechanism is directly installed on the bar by attachment or the like, but also includes the case where the feed drive mechanism is indirectly installed through a member attached on the bar.

According to the second aspect of the present invention, since the feed drive mechanism is provided with the linear motor, non-contact movement becomes possible, and also since the there is no rotating portion, not only the endurance of the work carrying device can be improved, but also driving noise can be reduced. Further, since the linear motor is employed, not only wide installation space for the feed drive mechanism becomes unnecessary, but also high-speed carry and high-precision positioning can be realized. Further, since the linear motor has fewer components including no rotating component, the feed drive mechanism can be made small in size and light in weight.

According to the third aspect of the present invention, since the feed drive mechanism is provided with a servomotor, the cost for the feed drive mechanism is reduced, and since the conventional mechanism such as a ball screw mechanism, a rack and pinion mechanism or the like can be used for the power transmitting mechanism, maintenance and adjustment of the work carrying device and the pressing machine become easy.

According to the fourth aspect of the present invention, since a plurality of the work holders for plural processes are detachably attached to one feed carrier, in a transfer press having plural working processes, for example, the number of the feed carriers can be reduced, therefore the cost can be reduced. Thus the construction and control can be further simplified.

According to the fifth aspect of the present invention, since the pair of bars include fixed bars and movable bars, the movable bars can detached from the frames. Thus the movable bar can be detached so as to be moved out from the work transfer area when performing die changing, so that the work holder becomes easy to change, and die changing operation can be facilitated.

According to the sixth aspect of the present invention, the feed carrier is driven by the feed drive mechanism so as to move relative to the pair of the bars in the work transfer direction. Further, the base is driven by the lift drive mechanism so as to move relative to the feed carrier in the lift direction. Thus the work carrying device can perform at least two-dimensional motion in the work transfer direction and the lift direction.

Since the feed carrier moves relative to the bars in the work transfer direction, the moving range of feed carrier the in the work transfer direction becomes wide. Also, since the moving distance in the lift direction is usually smaller than the moving distance in the work transfer direction, the length of the feed carrier in the lift direction becomes small. Thus the feed carrier can be made small and light, and the feed drive mechanism and lift drive mechanism with small capacity can be used, therefore it becomes possible to install the feed drive mechanism and lift drive mechanism on the bar and the feed carrier.

Accordingly, different from the conventional art, since the feed box having a feed drive section housed therein becomes unnecessary, there is no feed box projected from the pressing machine body, so that the press device as a whole can be downsized. Further, since no feed box is projected, a work carrying-out device or the like can be provided in the vicinity of the pressing machine. Further, since the lift box, which is arranged together with the feed box between the uprights and has a lift drive section housed therein, also becomes unnecessary, the construction of the work carrying device can be simplified.

Herein the lift direction means a direction perpendicular to a plane including the pair of the bars.

Note that the case of installing the feed drive mechanism on the bar not only includes the case where the feed drive mechanism is directly installed on the bar by attachment or the like, but also includes the case where the feed drive mechanism is indirectly installed through a member attached on the bar.

Also, note that the case of installing the feed drive mechanism on the feed carrier not only includes the case where the lift drive mechanism is directly installed on the feed carrier by attachment or the like, but also includes the case where the lift drive mechanism is indirectly installed through a member attached on the feed carrier.

According to the seventh aspect of the present invention, due to the provision of the clamp drive mechanism for driving the base, the base can move in a clamp direction. Thus the work carrying device can perform three-dimensional motion in the feed direction, the lift direction, and the clamp direction with the feed drive mechanism, the lift drive mechanism, and the clamp drive mechanism. Thus it becomes possible to cope with various kinds of press working, so that versatility of the transfer press can be expanded.

Herein the clamp direction means a horizontal direction perpendicular to the work transfer direction, namely a direction in which the pair of bars move toward or away from each other.

According to the eighth aspect of the present invention, since at least one of the feed drive mechanism and the lift drive mechanism is provided with a linear motor, non-contact movement becomes possible, and also since the there is no rotating portion, not only the endurance of the work carrying device can be improved, but also driving noise can be reduced. Further, since the linear motor is employed, not only wide installation space becomes unnecessary, but also high-speed carry and high-precision positioning can be realized.

According to the ninth aspect of the present invention, since the clamp drive mechanism is provided with the linear motor, non-contact movement becomes possible, and also since there is no rotating portion, not only the endurance of the work carrying device can be improved, but also driving noise can be reduced. Further, since the linear motor is employed, not only wide installation space becomes unnecessary, but also high-speed carry and high-precision positioning can be realized.

According to the tenth aspect of the present invention, since at least one of the feed drive mechanism and the lift drive mechanism is provided with a servomotor, the cost for the feed drive mechanism and/or the lift drive mechanism is reduced, and since the conventional mechanism such as a ball screw mechanism, a rack and pinion mechanism or the like can be used for the power transmitting mechanism, maintenance and adjustment of the work carrying device and the pressing machine become easy.

According to the eleventh aspect of the present invention, since the clamp drive mechanism is provided with a servomotor, the cost for the clamp drive mechanism is reduced, and since the conventional mechanism such as a ball screw mechanism, a rack and pinion mechanism or the like can be used for the power transmitting mechanism, maintenance and adjustment of the work carrying device and the pressing machine become easy.

According to the twelfth aspect of the present invention, since a plurality of the work holders for plural processes are installed to the base, in a transfer press having plural working processes, for example, the number of the feed carrier and the number of the lift carrier and the clamp carrier, both moving together with the feed carrier, can be reduced, therefore the cost can be reduced. Thus the construction and control can be further simplified.

According to the thirteenth aspect of the present invention, due to the provision of the bar-interval adjusting device, the interval between the pair of bars can be adjusted to an optimal value. Further, in the case that the work carrying device has a clamp drive mechanism, when setting a maximum moving distance of the clamp drive mechanism, since the dimension of the bar interval need not to be added to the maximum moving distance (maximum clamp amount), the maximum moving distance of the clamp drive mechanism can be reduced. Thus the weight of the base can be reduced. Further, when exchanging the die mounted on the moving bolster while performing the die exchanging operation in the outside of the pressing machine, since the bar interval can be automatically widened with the bar-interval adjusting device, die exchanging operation is further facilitated.

According to the fourteenth aspect of the present invention, since the pair of bars can be detached from the frames, when performing die changing, the bars can be detached and mounted on the moving bolster so as to be moved out from the work transfer area together with the moving bolster. Thus the work holder becomes easy to change, and die changing operation can be facilitated.

According to the fifteenth aspect of the present invention, since the motion of each feed carrier is individually controllable, the setting such as the moving distance and the moving timing of the feed carrier can be freely set corresponding to the die. Thus it is possible to flexibly cope with various kinds of press working, so that versatility of the transfer press can be expanded.

Further, since the work feed stroke and the feed speed corresponding to a feed position can respectively be set for each feed carrier, optimal feed motion can be obtained for the die of each working process, the pressing machine can be driven at high speed, feed miss can be reduced, and productive efficiency can be improved.

According to the sixteenth aspect of the present invention, since the adjacent feed carriers are connected to each other via a connector, when one feed carrier is driven, other feed carriers connected via the connector will be driven too at the same time in the work transfer direction. Thus it is unnecessary to provide a feed drive mechanism for each of the feed carriers, therefore not only number of components of the feed drive mechanism is reduced so that the cost can be reduced, but also the structure and control can be further simplified.

EXPLANATION OF CODES

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment

FIG. 1is a front elevational view showing a transfer press (pressing machine)1according to the first embodiment of the present invention.FIG. 2is a perspective view showing a transfer feeder (work carrying device)41.

Entire construction of the transfer press1as the first embodiment of the present invention will be described below with reference toFIG. 1.

The transfer press1includes a press main body1A, dies11each having an upper die12and a lower die13, a moving bolster30, and the transfer feeder41. The press main body1A further includes a bed23, uprights21, a crown20, and a slide22. A general purpose robot7for carrying out the work is provided on the downstream side of the transfer press1.

The bed23, which is the base of the transfer press1, is provided below the floor (FL). A plurality of uprights21(the number is four in the present embodiment) are erected on the bed23, the uprights21being opposing to each other respectively in a feed direction (i.e., a direction parallel to a transfer direction of the work2) and in a clamp direction (i.e., a horizontal direction perpendicular to the feed direction, namely, a direction vertical to the paper surface inFIG. 1). A crown20with a slide drive device (not shown) housed therein is supported by the uprights21. A slide22that can be moved upward and downward by the slide drive device is suspended below the crown20. A plurality of upper dies12each corresponding to a press working process are detachably installed on the lower surface of the slide22along the feed direction. A moving bolster30is provided on the upper surface of the bed23. A plurality of lower dies13respectively paired with the plurality of upper dies12are detachably installed on the upper surface of the moving bolster30, each die13opposing to respective upper die12.

The moving bolster30will be described as below.

The moving bolster30can be carried out/in relative to the upper surface of the bed23in order to change the used dies11(the upper dies12and the lower dies13) with the dies11to be used next.

A rail (not shown) is provided on the floor and on the bed23, and the moving bolster30is provided with a drive device capable of self-running on the rail. When the moving bolster30runs in clamp direction driven by the drive device, the moving bolster30is carried out from (or carried into) the transfer press1, after passing through the space between the pair of the uprights21erected in parallel with the work transfer direction.

Incidentally, usually two sets of the moving bolsters30are prepared. When performing die changing, the moving bolster30with the used dies11installed thereon is changed in its entirety with the moving bolster30on which the dies11to be used next are installed outside the transfer press1in advance, so that the dies11can be automatically changed quickly according to the work.

The transfer feeder41will be described as below.

As shown inFIG. 2, the transfer feeder41is provided with a pair of bars14arranged on the right and left relative to the work transfer direction, feed carriers52movable relative to the bars14in the feed direction, feeding linear motors (feed drive mechanisms)53for moving the feed carriers52in the feed direction, and lift/clamp devices (lift drive mechanisms and clamp drive mechanisms)80for moving the feed carriers52in a vertical direction (i.e., a direction perpendicular to the feed direction and the clamp direction, namely a lift direction) and the clamp direction.

The pair of the bars14, which extend in parallel in the feed direction with a given distance therebetween, respectively have fixed bars141fixed to the lift/clamp devices80, and movable bars142capable of being detached from the fixed bars141when performing die changing.

On the bed23, two frames33A are respectively provided between two upstream uprights21on both sides in the work transfer direction, and between two downstream uprights21on both sides in the work transfer direction (FIG. 2shows only the frame33A between two upstream uprights21). The frames33A are respectively provided with the lift/clamp devices80. The pair of the movable bars142are respectively installed with a plurality of the feed carriers52paired with each other, and a plurality of the feeding linear motors53for moving respective feed carriers52in the feed direction.

FIG. 3is an enlarged perspective view showing the feed carriers52.FIG. 4is a cross section taken along line A-A ofFIG. 3. As shown inFIGS. 3 and 4, linear guides57are respectively provided on the inner surfaces of the pair of the bars14(i.e., the surfaces of the bars14facing to each other). The linear guide57includes a linear guide rail57A provided on the inner surface of the bar14extending in the feed direction and a linear guide holder57B fixed to the feed carriers52. Further, the outer surfaces of the bars14are also respectively provided with feeding rails51,51, which are similar to the linear guide57. Due to the provision of the linear guide57and the feeding rails51,51, the feed carriers52are held so as to be movable in the feed direction.

The feeding linear motor53includes a magnet plate54between the feeding rails51,51, and a coil plate55opposing to the magnet plate54. The magnet plate54is a fixed part provided on the outer surface of the bar14(i.e., the surface of the bar opposite to the inner surface) along the feed direction, and the coil plate55is a movable part fixed to the feed carrier52via a connecting member. When a current flows so that a shifting magnetic field is generated to the coil plate55, the coil plate55will move due to the attraction and repulsion force against the magnet plate54. The feed carrier52is moved along with the coil plate55, thus the feed carrier52is forced to perform a feed operation. The feeding linear motor53is provided for each of the feed carriers52, so that the plurality of feed carriers52can be individually moved in the feed direction, and the motion of the respective feed carriers52can be individually controlled.

Though herein the linear guide57is provided on the inner surface of the bar14, and the feeding linear motor53is provided on the outer surface of the bar14, the arrangement is not necessary to be limited thereto, but the linear guide57and the feeding linear motor53can be provided on the inner surface, outer surface, upper surface and lower surface of the bar14. Further, the linear guide57and the feeding linear motor53can also be provided on the same surface of the bar14.

In the case of a conventional feed device, though the bar is provided with a plurality of work holders in the feed direction, however, since the work holders are fixed to the bar at predetermined intervals respectively, the work holders can only perform the feed motion common to all working processes. Thus, not only the cost is increased due to low freedom in die designing and large variety of dies, but also productivity is difficult to be improved because the press operation can not be quickly performed corresponding to respective dies. Further, since the pitches between the dies (the work feed stroke) have to be set according to the die corresponding to the largest work, the entire pressing machine becomes unnecessary large, so that the plant cost becomes high.

In contrast, in the first embodiment, the bar14is provided with a plurality of feed carriers52in the feed direction, and the feed carriers52can individually perform optimal motion under the control of a controller (not shown). With such an arrangement, since the work transfer distance can be freely set for respective feed carrier52, and the optimal work feed strokes for respective works2can be set according to the size of dies11of respective working processes, the freedom in die designing becomes high, so that it becomes possible to design the optimal dies for respective working processes. Further, since work feed strokes for respective feed carriers52and feed speeds corresponding to respective feed positions can be freely set, the optimal feed motions can be obtained for the dies11of respective working processes, the transfer press1can be driven at high speed, feed miss can be reduced, and productive efficiency can be improved.

Further, since the feeding linear motor53, which has fewer components including no rotating component, is used as a feed drive mechanism for the feed carrier52, the feed drive mechanism can be made light in weight and small in size, so that the manufacturing cost for the feed drive mechanism can be reduced. Further, since the feeding linear motor53is small in size and light in weight, occurrence of chattering of the bar14can be suppressed when performing start operation, stop operation and inching operation, the transfer feeder41in its entirety can operate at high speed with high positional accuracy, so that the transfer press1can be driven at high speed. Further, since chattering of the bar14can be suppressed, noise can be suppressed during driving, so that not only the working environment can be improved, but also the durability in each part of the transfer feeder41can be improved. As a result, not only the transfer press1has excellent maintainability, but also the service life of the transfer press1is elongated.

A finger (work holder)76for holding the work2is detachably installed to the feed carrier52via a mounting bracket76A, the finger protruding toward the opposite bar14.

FIG. 5is a perspective view showing the finger76. As shown inFIG. 5, in the first embodiment, the feed carrier52is provided with plural fingers76(in the present embodiment, two fingers are provided), so that two works2(seeFIG. 3) can be held by the two fingers76and the other two fingers76(not shown) installed on the feed carrier52on the opposing side. Since the feed carrier52is provided with plural (the number corresponding to the number of the working processes) fingers76to hold the plural works2, the number of the feeding linear motor53can be reduced, so that not only the construction of the transfer feeder41can be simplified, but also the manufacturing cost can be reduced.

Incidentally, in the first embodiment, though the finger76, which positions and mounts the work2, is used as the work holder for holding the work2, the work holder is not limited thereto, and, for example, a gripper77as shown inFIG. 6for gripping the work2also can be used as the work holder. Alternatively, as shown inFIG. 7, the work holder also can be a vacuum cup79which sucks and holds the work2. Further, though the number of the finger76provided to the feed carrier52is the number necessary for holding the work2for performing two working processes in the first embodiment, the number of the fingers76can be the number necessary for performing one working process, three working processes, or more than three working processes. Note that the number of the fingers76for each work2needs not to be limited to two, but can be one, three, or more than three.

Further, though the description is based on the configuration in which the magnet plate of the linear motor is a fixed part and the coil plate is a movable part, the configuration also can be the one in which the magnet plate is a movable part and the coil plate is a fixed part.

The lift/clamp device80which moves the bar14in the vertical direction (i.e., the lift direction) and the clamp direction will be described as below.

FIG. 8is a perspective view showing the lift/clamp device80. As shown inFIG. 8, the lift/clamp device80, which includes a lift device (a lift drive mechanism)81and a clamp device (a clamp drive mechanism)91, is provided in the frame33A. There are two lift/clamp devices80respectively connected to the fixed bars141of respective bars14.

The upper part of the lift device81is installed to the bar14, and the lower part of the lift device81is provided with two lift bars83,83, each having a cam follower83A that can move in the clamp direction, and a lift carrier82that rises and descends the bar14in the vertical direction (i.e., the lift direction) through the lift bar83and the cam follower83A. Further, a nut85is fixed to the lift carrier82. Further, a lift drive motor84for rotating a screw86, so that the lift carrier82is lift-driven together with the nut85engaged with the screw86. Further, in order to smooth the rising/descending motion of the lift carrier82and to balance the weight of the bar14and the lift carrier82, lift balancers87,87are respectively installed to the lift carrier82at two end portions thereof in the clamp direction.

The clamp device91is provided with a clamp carrier92arranged between the two lift bars83,83, and a linear guide93for guiding the clamp carrier92to move in the clamp direction, as well as a clamp drive motor94for driving the clamp carrier92in the clamp direction, a screw96, and a nut95.

The two lift bars83,83penetrate through the clamp carrier92such that the clamp carrier92can move in the vertical direction. The linear guide93includes a linear guide rail provided on the upper face of the frame33A and extending in the clamp direction, and a linear guide holder fixed to the lower face of the clamp carrier92. With such an arrangement, the clamp carrier92not only can be moved in the vertical direction relative to the lift bar83, but also can be moved in the clamp direction due to the provision of the linear guide93.

The screw96is connected to the clamp drive motor94, the screw96extending in the clamp direction and penetrating the clamp carrier92. The nut95is fixed to the clamp carrier92, the nut95being engaged with the screw96. When the clamp drive motor94is driven, the screw96is rotated, so that the clamp carrier92, to which the nut95is fixed, moves in the clamp direction. Thus the cam follower83A rolls and moves along the lift carrier82, and the lift bar83moves in the clamp direction. Thus the bar14moves in the clamp direction.

Incidentally, the pair of the bars14respectively perform motions in mutually opposite directions. Namely, the pair of the bars14move toward or away from each other.

The operation of the transfer feeder41of the present invention shown inFIGS. 1 and 2will be explained as follows by exemplifying a case where a work2is being carried into the transfer press1.

FIG. 9illustrates the motion of the finger76in the first embodiment.

(1) First, the work2is carried and placed onto a work receiving table (not shown) arranged in a work carrying-in position of the bar14(a position at an upstream end of the bar14) by a transfer device such as a general purpose robot (not shown). At this time, the bar14is in down position (at downward end of the bar14, namely at downward end of a lift stroke) as well as in unclamp position (at outward end of the bar, namely at outward end of a clamp stroke). When the bars14are moved toward each other driven by respective clamp devices91, the feed carrier52is moved toward clamp position (at inward end of the bar, namely at inward end of a clamp stroke), so that the bar14on the work receiving table is mounted to the finger76installed on the feed carrier52.
(2) Next, in the state where the work2is mounted on the finger76, when the bar14is lifted up by the lift device81, the feed carrier52follows the motion of the bar14to perform a lift motion from the down position to a lift position (at upward end of the lift stroke). Further, when the feed carrier52in the uppermost stream is individually driven by the feeding linear motor53, the feed carrier52performs a feed motion to the position of a first working process (a working process performed on left end of slide22inFIG. 1) of press-molding work. Consequently, the work2mounted on the finger76is transferred (carried forward) to the first working process from outside of the transfer press1. Note that the plurality of feed carriers52are not limited to be subjected to controlled drive individually, but can be subjected to controlled drive simultaneously so that all feed carriers52perform the same operation.
(3) Upon the work2reaches the position of the first working process of press-molding work, the lift device81is driven so as to move the bar14to the down position in order to set the work2onto the lower die13of the first working process of press-molding work.
(4) After the work2is set onto the lower die13, when the bar14is driven by the clamp device91so as to move away from the other bar14, the feed carrier52follows the motion of the bar14to perform an unclamp motion from the clamp position to the unclamp position, so that the finger76is retreated from the work2. Further, when the feed carrier52is driven by the feeding linear motor53, the feed carrier52is returned (carried backward) from the first working process toward the work receiving table until reaching the work receiving table again.

Incidentally, after the finger76is moved to the unclamp position (namely the bar moves backward) to retreat from the area of interfering with the die11, the slide22is descended to descend the upper die12installed on the lower surface of the slide22, so that a predetermined press-molding work of the first working process is performed by pressuring and holding the work2between the upper die12and the lower die13.

Next, the details of carrying the work2into the position of a next working process and performing press-molding work of the next working process are the same as the details of carrying the work2into the position of the first working process from the carrying-in position by the transfer feeder41and performing press-molding work of the first working process to the work2. That is, the details of carrying the work2from the position of the first working process to the position of a second working process of press-molding work by the transfer feeder41and the details of performing press-molding work of the second working process to the work2are the same as described above. Further, the details of carrying the work2from the position of the second working process to the position of a third working process by the transfer feeder41and the details of performing press-molding work of the third working process to the work2are the same as described above.

After the press-molding work of a lowermost stream working process (a fifth working process in the present embodiment) has been performed to the work2in the position of the lowermost stream working process, the work2is transferred from the position of the lowermost stream working process to a work receiving table located in a work carrying-out position of the bar14(a position at the downstream end of the bar14) by the transfer feeder41. The press-processed work2transferred to the work receiving table located in a work carrying-out position is then carried outside the pressing machine by the general purpose robot7.

As described above, the transfer feeder41of the present invention performs a three-dimensional operation. Specifically, the feed carrier52repeatedly performs a feed/return motion relative to the bar14in the work transfer direction, the bar14repeatedly performs a rising/descending motion (i.e., a lift/down motion), and the bar14also repeatedly performs a clamp/unclamp motion in a horizontal direction perpendicular to the work transfer direction. By appropriately reciprocating the work holder (the finger76) held on the feed carrier52in the feed direction, the lift direction and the clamp direction, the work2is sequentially transferred from the lower die13on an upstream side (the left side inFIG. 1) to the lower die13on a downstream side (the right side inFIG. 1).

FIG. 10is a top view of the transfer press1illustrating the positions of the feed carriers52at the time when a work2is carried from the work receiving table (not shown) in the work carrying-in position to the uppermost stream working process (the first working process in the present embodiment) of the transfer press1. InFIG. 10, the fingers76in the uppermost stream are positioned outside a bolster31of the moving bolster30, namely, are positioned at a location that is projected from the bolster31and the moving bolster30, in the plan view of the transfer press1(namely when viewed from a direction vertical to the paper surface ofFIG. 10). At this time, the fingers76in the uppermost stream are positioned on the upstream side of the downstream part of the two uprights21on the upstream side. This position is the position for performing an idle process for carrying-in work. On the other hand, at this time, the fingers76in the lowermost stream are positioned in the lowermost stream working process (the fifth working process in the present embodiment). In this state, when the works2are mounted on respective fingers76, the material (the work2) supplied from the outside of the transfer press1is mounted on the fingers76in the uppermost stream, and the works2finished with respective stages of working process are mounted on other fingers76. In this state, the respective feed carriers52are moved in the feed direction, so that the works2are respectively transferred to the next working process.

FIG. 11is a top view of the transfer press1illustrating the positions of the feed carriers52at the time when a work2is carried out from the lowermost stream working process of the transfer press1toward the work receiving table (not shown) located in the work carrying-out position. InFIG. 11, the respective feed carriers52are in the state of having finished the movement for transferring respective works2from the positions of the previous stage of working process (the positions shown by alternate long and two short dashes lines inFIG. 11) to the positions of the next stage of working process. InFIG. 11, the fingers76in the uppermost stream are positioned in the uppermost stream working process. On the other hand, the fingers76in the lowermost stream are positioned outside the bolster31, namely, are positioned at location that is projected from the bolster31and the moving bolster30. At this time, the finger76in the lowermost stream is positioned on the downstream side of the upstream part of the two uprights21on the downstream side. This position is the position for performing an idle process for carrying out a work. When the respective fingers76transfer the respective works2finished with respective stages of working process to the next stage of working process, the fingers76which mount the work2finished with the lowermost stream working process transfer the work2to the outside of the transfer press1, so that the work2is carried outside the transfer press1so as to be transferred to the general purpose robot7.

Since the installation space near a conventional feed box is narrow, a general purpose robot can not be set adjacent to pressing machine on its downstream side, therefore a discharge conveyor has to be employed. Thus not only a wide space for installing entire press device is necessary, but also facility cost becomes high. Further, in the case where the feed box is projected from the lateral surface of the press main body, a stack section for material has to be provided on the upstream side of the feed box, therefore not only a wide space for installing entire press device is necessary, but also major restriction is caused on the installation space for the material charging device, as a result an unreasonable structure has to be adopted.

Different from the conventional drive mechanism in which the bar14itself performs all three-dimensional motions of the feed/return motion, the rising/descending motion (i.e., the lift/down motion), and the clamp/unclamp motion, in the first embodiment, the motion of the finger76in the feed direction (which requires a long stroke) is performed by the feed drive mechanism (the feeding linear motor53) that is directly provided on the bar14to move the feed carrier52, to which the finger76is installed, in the feed direction along the longitudinal direction of the bar14.

With such an arrangement, the feed drive mechanism, which requires a long stroke, can be compactly installed in the press main body1A. Thus the conventional feed box projected from the lateral surface of the press main body is eliminated, and the space can be used for setting the general purpose robot7, so that a discharge conveyor becomes unnecessary. Thus not only a wide installation space for the pressing machine is unnecessary, but also facility cost becomes low.

Further, since the general purpose robot and the stack section for material can be installed adjacent to the pressing machine, not only a spatially wide factory layout can be provided, but also cost can be reduced. Further, since restriction on the space for installing the material charging device becomes less, the structure can be optimized.

Further, since the conventional feed device has to move a long and heavy bar at high speed, high output and high rigidity are required for the drive device thereof, therefore a large-sized expensive feed device has to be used. However, according to the first embodiment, since the feeding linear motor53is arranged on the bar14, the object to be driven is small in size and light in weight, therefore only a low drive output is needed. Thus, not only the transfer feeder41can be downsized so as to reduce the manufacturing cost, but also energy can be saved. Further, the transfer feeder41in its entirety can operate at high speed with high positional accuracy, so that productivity can be improved.

However, when performing die changing, since respective fingers76are also need to be changed corresponding to the die, the fingers76,76need to be mounted on the moving bolster30together with the bars14so as to be moved out from the work transfer area. However, since the bar14is supported by the lift/clamp devices80provided in the frames33A, the bar14is prevented from being carried out.

To solve this problem, as shown inFIG. 12, the movable bar142of the bar14is split and removed from the fixed bar141. The moving bolster30is provided with a bar receiving table (not shown) equipped with an elevating/lowering device on the outside of the bar14to support the split bar14(the movable bar142), as shown inFIG. 12.

Incidentally, the bar receiving table can alternatively be provided with a drive section for moving the movable bar142in the clamp direction, so that when performing die changing outside the press main body, since the bar interval can be widened while exchanging the die mounted on the moving bolster30, die changing operation can be further facilitated.

Incidentally, when performing die changing, in the case where the feed carrier52is in a position of interfering with the uprights21on the upstream side or in a position of interfering with the uprights21on the downstream side, the feed carrier52can individually be moved to an optimal position (where the ends of the finger76and the feed carrier52are positioned within the space between the uprights21on the upstream side and the uprights21on the downstream side, as shown inFIG. 12) in advance. Thus the feed carrier52and the finger76installed on the feed carrier52can be retreated from the area of interfering with upright21so as to be quickly moved outside the pressing machine. Thus the time for performing ADC (automatic die changing) operation can be shortened and therefore machine operation rate can be enhanced.

Second Embodiment

A second embodiment of the present invention will be described below. Note that like components are denoted by like numerals as of the first embodiment and the explanation thereof will be omitted. The second embodiment differs from the first embodiment only in the point that, different from the transfer feeder41of the first embodiment, a transfer feeder41A of the second embodiment moves a plurality of feed carriers52connected to each other by a feeding linear motor53A horizontally installed on the bar14.

FIG. 13is a perspective view showing the transfer feeder41A according to the second embodiment of the present invention. As shown inFIG. 13, in the second embodiment, the fixed bar141at one end of the bar14is provided with a moving member58, which is movably guided in the feed direction by a linear guide57provided between the moving member58and the upper surface of the bar14. The moving member58, the linear guide57, and the feeding linear motor53A form the feed drive mechanism of the present invention.

Since a pair of the bars14, each having a feed drive mechanism, are provided, there are provided two feed drive mechanisms. Herein the linear guide57includes linear guide rails57A and a linear guide holder57B. The linear guide rails57A are provided on the fixed bar141at the upstream end of the bar14and extend in parallel in the longitudinal direction (i.e., the feed direction) of the bar14. The linear guide holder57B is attached on the lower face of the moving member58for moving on the linear guide rail57A.

The feeding linear motor53A includes a magnet plate54A and a coil plate55A. The magnet plate54A is provided on the fixed bar141and extends in parallel with the linear guide57. The coil plate55A is provided on the lower face of the moving member58.

A connectors56for connecting the plurality of feed carriers52are provided to the moving member58on the face thereof corresponding to the outer surface of the bar14. The connectors56are provided between the moving member58and the feed carrier52in the uppermost stream, and between the feed carriers52adjacent to each other. The plurality of feed carriers52, which are connected with each other by the connectors56, are connected to the moving member58. The mutual intervals between the respective feed carriers52are adjusted to a predetermined work transfer pitch by the connectors56. Each feed carrier52is movably guided in the feed direction by linear guide rails59A, which are provided on the bar14along the longitudinal direction of the bar14, and a linear guide holder59B attached on the lower face of the feed carrier52for moving on the linear guide rails59A.

The present embodiment is similar to the first embodiment regarding the other portions than the above mentioned feed drive mechanism, and the description in this regard is omitted.

According to the second embodiment, since the adjacent feed carriers52are connected with each other by the connectors56and connected to the moving member58, when the moving member58is moved by the feeding linear motor53A in the feed direction, the plurality of feed carriers52move together while retaining the predetermined mutual intervals between respective feed carriers52.

Incidentally, when performing die changing, the bar14is split into two parts of the movable bar142and the fixed bar141. Thus the bar14is provided with a connecting device in the split parts thereof. The connector56is also provided with a connecting device near the connecting device of the bar14, so that when performing die changing, the connector56is also split into a movable part and a fixed part, similar to the bar14.

In the transfer feeder41A according to the second embodiment, though a plurality of the feed carriers52are provided on the bar14in the feed direction, since the adjacent feed carriers52are connected with each other by respective connectors56, only one feeding linear motor53A is necessary for each of the bars14.

Thus, since the feed drive mechanism can be made small in size and light in weight by employing a simple structure with small number of component, not only energy can be saved due to low feed drive output, but also manufacturing cost can be reduced.

Third Embodiment

A third embodiment of the present invention will be described below. Note that like components are denoted by like numerals as of the first and second embodiments, and the explanation thereof will be omitted. The third embodiment differs from the first embodiment in that, in the third embodiment, the feed carrier52of the first embodiment is driven by a servomotor.

FIG. 14is a perspective view showing a part of a transfer feeder41B according to the third embodiment. As shown inFIG. 14, similar to the first embodiment, a pair of bars14AA are provided in parallel in the work transfer direction, and a plurality of feed carriers52B are provided on a pair of feeding rails51,51installed on the upper surface of the bar14AA, the feed carrier52B being individually movable. Note that thoughFIG. 14shows only one feed carrier52B, the number of the feed carrier52B can be any according to necessity.

The feed carrier52B, driven by a feeding servomotor (feed drive mechanism)53B provided to the bar14AA, performs a feed operation. The bar14AA is provided with a ball screw54B which is chain-driven by the feeding servomotor53B, and when the ball screw54B rotates, a ball nut (not shown) provided to the feed carrier52B moves, so that the feed carrier52B moves together with the ball nut. In this manner the feed carrier52B performs the feed operation.

Since the feed carrier52B is driven by the feeding servomotor53B, the cost of the feed drive mechanism can be reduced. Also, since the ball screw mechanism is used for the power transmitting mechanism, maintenance and adjustment of the transfer feeder41B and the transfer press1become easy. Incidentally, a rack and pinion mechanism or the like also can be used for the power transmitting mechanism of the feeding servomotor53B.

Note that though the above embodiments are explained using an example in which a general purpose robot provided on the downstream side of the pressing machine is used for carrying out the work, the case also can be the one in which a general purpose robot provided on the upstream side of the pressing machine is used for carrying in the work, or the case can be the one in which two general purpose robots are provided respectively for carrying in and carrying out the work.

Further, though the frames33A are arranged on the bed in the above embodiments, the frames33A also can be arranged above the bar14between the uprights21as shown inFIG. 15. In such a case, since the bar14is suspended, the feed carriers52are supported by the lower surface of the bar14. By arranging the frames33A in such a way, the visibility inside the transfer press1can be improved.

Fourth Embodiment

FIG. 16is a front elevational view showing a transfer press (pressing machine)1having a work carrying device according to a fourth embodiment of the present invention.FIG. 17is a perspective view showing a transfer feeder41C which is the work carrying device.FIG. 18is an enlarged perspective view showing a part of the transfer feeder41C.FIGS. 19 to 21are partly enlarged views of the transfer feeder41C. Note that like components are denoted by like numerals as of the first to third embodiments, and the explanation thereof will be omitted.

As shown inFIG. 16, four columnar uprights21are erected on a bed23disposed in the lower portion of a press frame10of the transfer press1, and a crown20is provided above the uprights21. A slide drive device is built into the crown20for driving a slide22disposed below the crown20upward and downward. Upper dies12are installed to a lower surface of the slide22. Lower dies13are installed to an upper surface of a moving bolster30opposed to the slide22, so that a work is press-formed by cooperation of the upper dies12with the lower dies13. A pair of bars14B,14B are provided on the right and left with the upper dies12and the lower dies13sandwiched therebetween, the pair of bars14B,14B extending in parallel in the work transfer direction.

As shown inFIG. 17, on the bed23, an upstream frame33A and a downstream frame33B are respectively provided between the two uprights21on the upstream side and between the two uprights21on the downstream side, both frames being arranged along the direction perpendicular to the work transfer direction. Each of the upstream frame33A and the downstream frame33B is provided with two pairs of moving rails42, which are parallel with each other in the direction perpendicular to the work transfer direction. Supports47A,47B,47C, and47D respectively provided on the lower sides at both ends of the bars14B,14B can move on the moving rails42. Thus the bar14B,14B are supported by the frames33A,33B located on both sides of the moving bolster30across the moving bolster30, in a manner of being movable in the direction perpendicular to the work transfer direction.

Racks43are respectively provided near the pairs of the moving rails42on the front side in parallel with the moving rails42, the racks43being respectively engaged with the pinions43P,43P respectively provided on the supports47A,47B. The supports47A,47B are respectively provided with interlocking racks34A,34A parallel with the moving rail42and extending toward the opposing supports47C,47D, the interlocking racks34A,34A respectively engaging with interlocking pinions35,35respectively provided at substantially centers of the frames33A,33B. Further, the supports47C,47D are respectively provided with interlocking racks34B,34B parallel with the moving rail42and extending toward the opposing supports47A,47B, the interlocking racks34B,34B respectively engaging with interlocking pinions35,35.

When a driving shaft (not shown) passed through the bar14B in the longitudinal direction is rotated by a moving motor44provided to the support47A, the pinions43P,43P rotate, gear-driven by the driving shaft. Thus, since the pinions43P,43P respectively engage with the racks43,43, the bar14B on the front side moves along with the supports47A,47B. When the interlocking racks34A,34A are also moved at the same time, since the interlocking pinions35,35are respectively engaged with the interlocking racks34B,34B, the interlocking racks34B,34B also move, so that the bar14B on the back side moves along with the supports47C,47D.

Thus a bar interval adjustment device40of the present invention is configured by the interlocking racks34A,34B and the interlocking pinion35, the bar interval adjustment device40being capable of adjusting the interval between the pair of bars14B,14B (that is, the bar14B on the front side and the bar14B on the back side when viewed fromFIG. 17). With the bar-interval adjusting device40, it becomes possible to flexibly cope with various kinds of press working by adjusting the interval between the pair of bars14B,14B corresponding to the die, therefore versatility of the transfer press1can be expanded.

As shown inFIGS. 17 and 18, a pair of feeding rails51,51are provided on an upper surface of each of the bars14B,14B, and a plurality of feed carriers52C are movably provided on the pair of feeding rails51,51. Though there are three feed carriers52C in the first embodiment, the number of the feed carrier52C can be one, two, four or more than four according to necessity.

The feed carrier52C, driven by a feeding linear motor (feed drive mechanism)53C (refer toFIG. 19), performs a feed operation. Herein, the feed operation means an operation in which the feed carrier52C moves along a feed direction. Further, the feed direction means a direction parallel to the work transfer direction.

FIG. 19is a cross section taken along line A-A ofFIG. 17. As also shown inFIGS. 19 and 18, the feeding linear motor53C has a magnet plate54C as a fixed part provided between the pair of the feeding rails51,51, and a coil plate55C as a movable part provided on a lower surface of the feed carrier52C, the coil plate55C being opposed to the magnet plate54C. When a current flows so that a shifting magnetic field is generated to the coil plate55C, the coil plate55C will move due to the attraction and repulsion force against the magnet plate54C. The feed carrier52C is moved along with the coil plate55C, thus the feed carrier52C is forced to perform a feed operation. Since each of the feed carriers52is provided with the feeding linear motor53, the plurality of the feed carriers52can be individually moved on the feeding rails51,51in the feed direction, and the movement of the respective feed carriers52can be individually controlled.

As shown inFIGS. 17,18and19, a pair of clamping rails61,61are provided on an upper surface of the feed carrier52C in a horizontal direction perpendicular to the feeding rail51, and a clamp carrier62is movably provided on the pair of clamping rails61,61. The clamp carrier62, driven by a clamping linear motor (clamp drive mechanism)63(refer toFIG. 20), performs a clamp operation. Herein, the clamp operation means an operation in which the clamp carrier62moves along a clamp direction. Further, the clamp direction means a horizontal direction perpendicular to the feed direction, namely a direction in which a pair of opposed clamp carriers62move toward or away from each other.

FIG. 20is an elevational view viewed from the direction B ofFIG. 19. As also shown inFIGS. 19 and 20, the clamping linear motor63has a magnet plate64as a fixed part provided between the pair of the clamping rails61,61, and a coil plate65as a movable part provided on a lower surface of the clamp carrier62, the coil plate65being opposed to the magnet plate64. When a current flows so that a shifting magnetic field is generated to the coil plate65, the coil plate65will move due to the attraction and repulsion force against the magnet plate64. The clamp carrier62is moved along with the coil plate65, thus the clamp carrier62is forced to perform clamp operation.

As shown inFIGS. 17 and 18, a pair of lifting rails71,71extending in the vertical direction are provided on a back-side surface (seeFIG. 17) of a L-shaped bracket66of the clamp carrier62(mutually facing surfaces of a pair of the L-shaped brackets66of the clamp carriers62), and a lift carrier72is movably provided on the pair of lifting rails71,71. The lift carrier72, driven by a lifting linear motor (lift drive mechanism)73(refer toFIG. 21), performs a lift operation. Herein, the lift operation means an operation in which the lift carrier72moves along a lift direction. Further, the lift direction means a direction perpendicular to both the feed direction and the clamp direction, namely a direction in which the lift carrier72moves vertically.

FIG. 21is an elevational view viewed from the direction C ofFIG. 19. As also shown inFIGS. 19 and 21, the lifting linear motor73has a magnet plate74as a fixed part provided between the pair of the lifting rail71,71, and a coil plate75as a movable part provided on a front surface (viewed fromFIG. 17) of the lift carrier72, the coil plate75being opposed to the magnet plate74. When a current flows so that a shifting magnetic field is generated to the coil plate75, the coil plate75will move due to the attraction and repulsion force against the magnet plate74. The lift carrier72is moved along with the coil plate75, thus the lift carrier72is forced to perform lift operation.

As shown inFIGS. 17 and 19, fingers76,76as work holders for holding works2,2are detachably installed to the lift carrier72. In the fourth embodiment, similar to the first embodiment, the lift carrier72is provided with two fingers76,76as shown inFIG. 5. By performing the clamp operation, two works2,2(refer toFIG. 18) can be simultaneously clamped with the two fingers76,76and the other two fingers76,76(not shown) of the lift carrier72on the opposing side.

Herein, since the fingers76,76are provided to the lift carrier72and the lift carrier72is provided to the clamp carrier62, the fingers76,76can move both in the lift direction and the clamp direction, so that in the fourth embodiment, the lift carrier72and the clamp carrier62are equivalents to a base50of the present invention.

Since the lift carrier72is provided with plural (the number corresponding to the number of working processes) fingers76,76to hold the plural works2, the number of the feeding linear motor53C, the clamping linear motor63, and the lifting linear motor73can be reduced, the construction of the transfer feeder41C can be simplified, and the manufacturing cost can be reduced.

Incidentally, in the fourth embodiment, though the finger76, which positions and mounts the work2, is used for the work holder for holding the work2, the work holder is not limited thereto, and for example a gripper77, as shown inFIG. 7, of the first embodiment for gripping the work2can be used. Further, in the fourth embodiment, though the lift carrier72is provided with two fingers76,76, the number of the fingers76can be one, three, or more than three, corresponding to the die.

Similar to the described above, the other bar14B is provided with feed carriers52C, clamp carriers62, and lift carriers72, and all these components respectively perform, driven by respective linear motors, the feed operation (for performing a movement parallel to the work transfer direction), the clamp operation (for performing a horizontal movement perpendicular to the feed direction), and the lift operation (for performing a movement in the vertical direction).

Further, though the description is based on the configuration in which the magnet plate of each linear motor is a fixed part and the coil plate is a movable part, the configuration also can be the one in which the magnet plate is a movable part and the coil plate is a fixed part.

The operation of the work carrying device in the fourth embodiment will be described below with reference toFIG. 17andFIG. 9described above. The operation will be described based on a case where a work is transferred from a first working process to a second working process.

(1) First, the work2is pressed in the first working process, and the slide22starts to rise.

At this time, the lift carrier72with the fingers76fixed thereon is in a down position (at the downward end of a lift stroke). Further, the clamp carrier62that holds the lift carrier72is in an unclamp position (at outward end of a clamp stroke). When the clamp carrier62is driven by the clamping linear motor63, the clamp carrier62performs a clamp motion along the clamping rails61,61from the unclamp position toward a clamp position (at inward end of the clamp stroke), so that the work2on the lower die13of the first working process is mounted on the fingers76.

(2) Next, in the state where the work2is mounted on the fingers76, when the lift carrier72is driven by the lifting linear motor73, the lift carrier72performs a lift motion from the downward position to a lift position (at the upward end of the lift stroke). Further, when the feed carrier52C is driven by the feeding linear motor53C, the feed carrier52C that holds the clamp carrier62is subjected to a controlled drive to perform a feed motion. Consequently, the work2mounted on the fingers76is transferred from the first working process to the second working process.
(3) Upon the work2reaches the second working process, the lift carrier72is driven by the lifting linear motor73, so that the lift carrier72is moved to the down position to set the work2onto the lower die13of the second working process.
(4) After the work2is set onto the lower die13, when the clamp carrier62is driven by the clamping linear motor63, the clamp carrier62performs an unclamp motion from the clamp position to the unclamp position, so that the fingers76are retreated from the work2. Further, when the feed carrier52C is driven by the feeding linear motor53C, the feed carrier52C performs a return motion from the second working process to the first working process until reaching the initial first working process again.

Incidentally, after the fingers76are moved to the unclamp position to retreat from the area of interfering with the upper die12, the slide22is descended, so that a predetermined press working of the second working process is performed by clamping the work2between the upper die12attached on the lower surface of the slide22and the lower die13and applying pressure.

As described above, the transfer feeder41C of the fourth embodiment is provided with the feed carrier52C movable relative to the bars14B,14B in the feed direction, the clamp carrier62movable relative to the feed carrier52C in the clamp direction, and the lift carrier72movable relative to the clamp carrier62in the lift direction. All these components are driven by the respective linear motors so as to respectively perform, in a reciprocating manner, the feed/return motion in the feed direction, the clamp/unclamp motion in the clamp direction (i.e., the horizontal direction perpendicular to the feed direction), and the rising/descending motion (i.e., the lift/down motion) in the vertical direction. All these motions constitute a three-dimensional operation. By appropriately reciprocating the work holder held on the lift carrier72in the feed direction, the lift direction and the clamp direction, the work2is sequentially transferred from the lower die13on an upstream side (the left side inFIG. 16) to the lower die13on a downstream side (the right side inFIG. 16).

Since the feed carriers52C are movably provided on the bars14B,14B, the object to be driven by the feed drive mechanism becomes small. Accordingly, different from the conventional art, since the feed drive mechanism can be made small, and the feed box having a feed drive section housed therein becomes unnecessary, there is no feed box projected from the lateral surface of the press main body, so that the transfer press1as a whole can be downsized. Further, since no feed box is projected, a work carrying-out device or the like can be provided in the vicinity of the transfer press1.

When performing die changing, since respective fingers76are also need to be changed corresponding to the die, the fingers76,76need to be mounted on the moving bolster30together with the bars14B,1413so as to be moved out from the work transfer10area. Herein, though the bars14B,14B themselves can be moved out from the work transfer area after passing through the space between the uprights21, the bar interval adjustment devices40connected to the bars14B,14B on the upstream and downstream sides are obstacles to moving out the bars14B,14B since the bar interval adjustment devices40are respectively arranged on the frames33A between the two uprights21on the upstream side and on the frames33B between the two uprights21on the downstream side.

To solve this problem, the bars14B,14B can be split from the bar interval adjustment device40(including the driving shaft), so that the bars14B,14B are split from the bar interval adjustment device40when performing die changing. Namely, in the fourth embodiment, the bars14B,14B can be split into fixed bars fixed to the bar interval adjustment devices40, and movable bars capable of being split from the fixed bars, so that the bars14B,14B can be detached from the bar interval adjustment devices40. Thus the bars14B,14B can be detached from the frames33A,33B.

Incidentally, as shown inFIG. 17, the moving bolster30is provided with bar receiving tables48equipped with elevating/lowering devices, and, similar to the first embodiment, the split, bars14B,14B are supported by the bar receiving tables48as shown inFIG. 12.

Incidentally, the bar receiving tables48are provided with drive sections for moving the bars14B,14B in the clamp direction, so that when exchanging the die mounted on the moving bolster30while performing die changing outside the press main body, die changing operation can be further facilitated by widening the bar interval.

Fifth Embodiment

Next, a transfer feeder41D of a fifth embodiment will be described below with reference toFIG. 22.FIG. 22is a perspective view showing a part of the transfer feeder41D. Since the fifth embodiment differs from the fourth embodiment in that the feed carrier52C, the clamp carrier62, and the lift carrier72of the fourth embodiment are driven by servomotors, these portions will be described with reference toFIG. 22. Also, since other portions are similar to those of the fourth embodiment, like components are denoted by like numerals as of the first to fourth embodiments, and the explanation thereof will be omitted.

As shown inFIG. 14, similar to the fourth embodiment, a pair of bars14BA are provided in parallel in the work transfer direction, and a plurality of feed carriers52D are provided on a pair of feeding rails51,51installed on the upper surface of each bar14BA, the feed carriers52D being individually movable. Note that thoughFIG. 22shows only one feed carrier52D, the number of the feed carrier52D can be any according to necessity.

The feed carrier52D, driven by a feeding servomotor (feed drive mechanism)53D provided to the bar14BA, performs a feed operation. The bar14BA is provided with a ball screw54D which is chain-driven by the feeding servomotor53D, and when the ball screw54D rotates, a ball nut (not shown) provided to the feed carrier52D moves, so that the feed carrier52D moves together with the ball nut. In this manner the feed carrier52D performs a feed operation.

A pair of clamping rails61,61are provided on an upper surface of the feed carrier52D in a horizontal direction perpendicular to the feeding rail51, and a clamp carrier62A is movably provided on the pair of clamping rails61,61. The clamp carrier62A, driven by a clamping servomotor (clamp drive mechanism)63A provided to the feed carrier52D, performs a clamp operation.

The feed carrier52A is provided with a ball screw64A which is driven by the clamping servomotor63A, and when the ball screw64A rotates, a ball nut (not shown) provided to the clamp carrier62A moves, so that the clamp carrier62A moves together with the ball nut. In this manner the clamp carrier62A performs clamp operation.

A pair of lifting rails71,71extending in the vertical direction are provided on the back-side surface (seen fromFIG. 22) of an L-shaped bracket66A of the clamp carrier62A, and a lift carrier72A is movably provided on the pair of lifting rails71,71. The lift carrier72A, driven by a lifting servomotor (lift drive mechanism)73A, performs a lift operation.

The lifting servomotor73A drives a ball screw74A, which is rotatably provided to the lift carrier72A, via a gear box73G provided to the lift carrier72A. When the ball screw74A rotates, a ball nut (not shown) provided to the lift carrier72A moves, so that the lift carrier72A moves together with the ball nut. In this manner the lift carrier72A performs lift operation. The present embodiment is similar to the first to fourth embodiments in that the lift carrier72A is detachably installed with a pair of fingers as a work holder for holding a work, and the description in this regard will be omitted.

Also, the present embodiment is similar to the first to fourth embodiments regarding the operations of the feed carrier52D, the clamp carrier62A, and the lift carrier72A, and the description in these regards will also be omitted.

Similar to the described above, the other bar (not shown) is also correspondingly provided with feed carriers, lift carriers, and clamp carriers, and all these components respectively perform, driven by respective servomotors, the feed operation, the lift operation, and the clamp operation.

As described above, the transfer feeder41D of the fifth embodiment is provided with the feed carrier52D movable relative to the bar14BA in the feed direction, the clamp carrier62A movable relative to the feed carrier52D in the clamp direction, and the lift carrier72A movable relative to the clamp carrier62A in the lift direction. All these components are driven by the respective servomotors to respectively perform the feed operation, the clamp operation, and the lift operation under the control of a controller (not shown), so that consequently the transfer feeder41D operates as a three-dimensional transfer feeder. By appropriately reciprocating the work holder held on the lift carrier72in the feed direction, the clamp direction and the lift direction, the work2is sequentially transferred from the lower die13on an upstream side (the left side inFIG. 16) to the lower die13on a downstream side (the right side inFIG. 16).

Sixth Embodiment

Next, a transfer feeder41E of a sixth embodiment will be described below with reference toFIG. 23.FIG. 23is a perspective view showing a part of the transfer feeder41E which is the work carrying device. Note that like components are denoted by like numerals as of the first to fifth embodiments, and the explanation thereof will be omitted.

The sixth embodiment differs from the fourth embodiment in that the adjacent feed carriers52C are connected to each other via a connector56A. Accordingly, the plurality of feed carriers52C are so arranged that the adjacent feed carriers52C are connected to each other with a predetermined interval. With such an arrangement, since all of feed carriers52C supported by the single bar14are operated in an interlocked manner, it is unnecessary to provide a feed drive mechanism for each of the feed carriers52C.FIG. 23shows a case where only the feed carrier52C on the upstream side is provided with a linear motor (a feed drive mechanism)53E.

Incidentally, the configuration also can be the one in which all of the feed carriers52C are respectively provided with linear motors as in the fourth embodiment, and all of the linear motors are simultaneously driven.

The present embodiment is similar to the fourth embodiment regarding the operation of the transfer feeder41E, and the description in this regard is omitted.

Seventh Embodiment

Next, a transfer feeder41F of a seventh embodiment will be described below with reference toFIG. 24.FIG. 24is a perspective view showing a transfer feeder41F which is the work carrying device. Note that like components are denoted by like numerals as of the first to sixth embodiments, and the explanation thereof will be omitted.

The seventh embodiment differs from the fourth embodiment in that the clamping linear motor63is eliminated, and the lift carrier72is held by the feed carrier52C. With such an arrangement, carriers72respectively provided on the pair of bars14are paired with each other with a constant interval therebetween, and cross bars78are horizontally stretched between the pairs of lift carriers72. The cross bar78is provided with vacuum cups (work holders)79for sucking and holding the work by negative pressure. In the seventh embodiment, since the vacuum cups79are held by the lift carrier72via the cross bar78, and the lift carrier72can move in the lift direction, so that the lift carrier72is equivalent to a base50A of the present invention.

With such a configuration, the feed carrier52C performs the feed motion and the lift carrier72performs the lift motion, therefore the transfer feeder41F of the seventh embodiment can perform two-dimensional operation.

The operation of the work carrying device in the seventh embodiment will be described below with reference toFIG. 24andFIG. 25that explains the motion of the seventh embodiment. The operation will be described based on a case where a work is transferred from a first working process to a second working process.

(1) First, the work2is pressed in the first working process, and the slide22starts to rise.

At this time, the cross bar78provided on the lift carrier72is in a standby position in the middle between the first working process and the second working process. In the standby position, the lift carrier72is in a lift position (at the upward end of a lift stroke). After the press working is finished, the feed carrier52C that holds the lift carrier72is subjected to a controlled drive to perform a return motion toward the side of the first working process. And the cross bar78is moved from the standby position to the first working process.

Next, the lift carrier72is descended to a down position (at the downward end of a lift stroke), and the work2on the lower die13of the first working process is sucked and held by the vacuum cups79of the cross bar78.

(2) Next, in the state where the work2is sucked and held by the vacuum cups79, the lift carrier72performs lift motion to a lift position (at the upward end of a lift stroke). Further, the feed carrier52C is subjected to a controlled drive to perform a feed motion. Thus the work2sucked and held by the vacuum cup79is transferred from the first working process to the second working process.
(3) Upon the work2reaches the second working process, the lift carrier72is moved to the down position to set the work2onto the lower die13of the second working process. And the sucking force of the vacuum cup79is released.
(4) After the work2is set onto the lower die13, the lift carrier72is moved to the lift position and the feed carrier52C is subjected to a controlled drive to perform a return motion toward the initial standby position.

Incidentally, after the cross bar78is moved to the standby position and retreated from the area of interfering with the upper die12, the slide22is descended, so that a predetermined press working of the second working process is performed by clamping the work2between the upper die12attached on the lower surface of the slide22and the lower die13and applying pressure.

As described above, the transfer feeder41F of the seventh embodiment is provided with the feed carrier52C movable relative to the bar14in the feed direction, and the lift carrier72movable relative to the feed carrier52C in the lift direction. All these components are driven by the respective linear motors to respectively perform, in a reciprocating manner, the feed/return motion in the feed direction, and the rising/descending motion in the vertical direction. All these motions constitute a two-dimensional operation. By appropriately reciprocating the cross bar78installed to the lift carrier72and the vacuum cups79installed to the cross bar78in the feed direction and the lift direction, the work2is sequentially transferred from the lower die13on an upstream side (the left side inFIG. 24) to the lower die13on a downstream side (the right side inFIG. 24).

Incidentally, though the vacuum cups79as work holders are installed to the cross bar78in the seventh embodiment, the vacuum cups79can also be installed to the lift carrier72as shown inFIG. 26.

Further, in the seventh embodiment, the clamping linear motor63is eliminated compared to the fourth embodiment, but the configuration also can be the one in which the configuration is the same as the fourth embodiment but with the drive of the clamping linear motor63stopped so that the cross bar78and the vacuum cups79perform two-dimensional operation.

Also, though either linear motors or servomotors are employed for the respective drive mechanisms in the previous embodiments, a combination of the linear motor and servomotor can also be employed. For example, the work holder can be moved by using a linear motor to perform the feed motion and a servomotor to perform the lift motion and the clamp motion, and at least one driving source is linear motor. Also, the work holder can be moved by using servomotor to perform the feed motion and linear motor to perform the lift motion and the clamp motion, and at least one drive mechanism is servomotor. In other words, the linear motor and the servomotor can be used as the drive mechanism for feeding, clamping, and lifting according to necessity.

Incidentally, though the above description is based on a so called two-pillar type transfer press which has four uprights and one slide, the present invention also can be applied to a pressing machine such as a so called three-pillar type transfer press which has six uprights and two slides, or other transfer press which has more uprights and slides.

Incidentally, the effects of the work carrying device of pressing machine according to the present invention also can be obtained in retrofitting.

As a recent trend in the field of the pressing machine, retrofitting of the pressing machine is actively performed, such as retrofitting an existing pressing machine by changing a cam-actuated work carrying device thereof with a servomotor-actuated device, so that the function of the pressing machine can be improved in terms of speed, capability for coping with various works, and the like.

However, when performing such a retrofitting work, it is necessary to change the feed box, which is a main part of the feed device, projected from the lateral surface of the press main body on the work carrying-out side (or the work carrying-in side). Since the feed box is large and heavy, and since the feed box is projected from the lateral surface of the pressing machine body, a number of working days will be necessary for exchanging the feed box (including the work for welding a feed box mounting seat onto the pressing machine body).

Since the operation of the process line has to be stopped for long time to perform such retrofitting work, the retrofitting work is usually performed during a long-term holiday such as New Year's holiday. However in the case that more construction days become necessary for perform the retrofitting work, the operation of the process line has to be stopped even in the period before or after such a long-term holiday, therefore the users, who do not want the operation of the process line to be stopped for long time, can not be satisfied.

However, according to the present invention, since the feed carrier is movably provided on the bar, the object to be driven by the feed drive mechanism can be made small, thus the feed drive mechanism can be made small. Accordingly, if the retrofitting is performed by adopting the work carrying device of pressing machine according to the present invention, since the existing large-scale feed box is simply removed, instead of being changed with a new large-scale feed box, a big construction work will be unnecessary. Thus the retrofitting work can be finished in few days by an easy construction work in which a size-reduced feed device is assembled with the lift device and the clamp device in advance, and then the assembly is exchanged with the old one.

Since the operation of the process line is stopped for shorter time, the retrofitting work can be finished within a long-term holiday such as New Year's holiday, thus the production plan of the users will not be affected. In other words, working days for retrofitting can be reduced, and impact to production efficiency of the user can be minimized.

Also, though the preferred configurations, methods and the like for carrying out the present invention are described above, the present invention is not intended to be limited thereto. In other words, though the present invention is mainly illustrated and described based on specific embodiment thereof, it should be understood that various changes in the shape, material, quantity, and other details of construction can be made by those skilled in the art based on the embodiment described above without departing from the spirit and objects of technical characteristics of the present invention.

Accordingly, the description disclosed above, which gives specific shape, material and the like, is just an exemplary description to make the present invention well understood instead of being a definition of the limits of the invention, therefore the description based on a component name without part or all of the specific shape, material and the like is included in the present invention.

INDUSTRIAL APPLICABILITY

With the work carrying device of pressing machine as described in present invention, since a large driving mechanism is not necessary, the construction can be simplified. Further, since the work carrying device is arranged in its entirety on the moving bolster, die exchanging can be easily performed. Accordingly, the present invention also can be applied to a pressing machine which mounts various kind of dies.