Patent Publication Number: US-7219525-B2

Title: Work transfer apparatus for transfer press

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a divisional application of U.S. application Ser. No. 10/280,972, filed Oct. 25, 2002, now U.S. Pat. No. 7,124,616. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a work transfer method for a transfer press, and a work transfer apparatus for a transfer press or a press. 
     BACKGROUND ART 
     A transfer feeder for transferring a work between the working stations in succession is conventionally placed in a transfer press including a plurality of working stations in a press main body. The transfer feeder includes a pair of parallel transfer bars at left and right with respect to a work transfer direction, and each of the transfer bars has a long length to extend along all the working stations. 
     As a conventional transfer feeder, the one is disclosed in, for example, in Japanese Patent Laid-open No. 11-104759, and according to the Laid-open Patent, a pair of left and right transfer bars are constituted by long integrated bars extending along all the working stations. The transfer bar is provided with a plurality of suction tools with predetermined spaces from each other in the work transfer direction to be ascendable and descendable, and movable in the lateral direction (clamp direction) and the longitudinal direction (transfer direction) by a linear motor. As a result, it is made possible to correspond to a change of the work in the clamp/unclamp direction by the aforementioned suction tools when transferring a work. 
     As another example of the prior art of the transfer feeder, for example, the one disclosed in Japanese Patent Laid-open No. 10-314871 is cited. According to the Laid-open Patent, in the transfer feed bar drive device, the transfer bar (feed bar of the same Laid-open Patent) includes a feed carrier, to which the transfer bar is connected so as to be movable up and down and in the lateral direction and restricted in the movement in the longitudinal direction, and a feed unit for moving the feed carrier back and forth by a linear motor. 
     As still another example of the prior art of the transfer feeder, the one is disclosed in for example, Japanese Patent Publication No. 7-73756. According to the same Patent Publication, a plurality of carriers are provided at a pair of vertically movable guide rails at left and right with respect to the work transfer direction (corresponding to the aforementioned transfer bar) to be independently movable by a linear motor. The cross bar is spanned between the carriers opposing each other with each working station between them, a work is sucked with the work holding means including the cross bar, and the cross bar is moved along the guide rail by the aforementioned linear motor, whereby the work is transferred. 
     However, the above-described conventional transfer bar has the following problems. 
     The transfer bars described in Japanese Patent Laid-open No. 11-104759 and Japanese Patent Laid-open No. 10-314871 are each constituted by an integrated bar extending along all the working stations, and there is only one system of the driving source in the feed direction. Consequently, adjustment of each stroke of the feed, lift, and work transfer height (so-called feed level) of each process has limitation to some extent. Namely, concerning the feed stroke, the transfer pitch (distance between the processes) is constant, and therefore the work transfer is difficult in the transfer press in which the pitches between the adjacent working stations differ. In addition, the die has to be designed so that the distances between the processes are equal, which causes the problem that it is difficult to design an optimal die in consideration of the interference curve and the like. Further, concerning the lift and work transfer height, they have to be equal between the respective working stations, which makes it difficult to design an optimal die corresponding thereto. 
     The transfer bar described in Japanese Patent Publication No. 7-73756 is constituted so that a plurality of carriers can be self-propelled independently by the respective linear motors. However, there arises the problem that the lift stroke and the work transfer height cannot be adjusted for each process since the transfer bars (guide rails) are constituted by integrated bars extending along a plurality of working stations as described above. 
     SUMMARY OF THE INVENTION 
     The present invention is made in view of the above-described problems, and has its object to provide a work transfer method and a work transfer apparatus for a transfer press, which is capable of individually adjusting a feed stroke, a lift stroke and work transfer height for each process, and with which an optimal die can be designed for each process. The present invention has another object to provide a work transfer apparatus for a press which is capable of individually adjusting the feed stroke for each process, and facilitating work transfer with different pitches between adjacent working processes. Further, it has still another object to provide a work transfer apparatus for a press which is capable of individually adjusting the lift stroke and the work transfer height for each pair of lift beams, and with which an optimal die can be designed. 
     In order to attain the above-described object, a work transfer method for a transfer press according to the present invention includes the steps of
     carrying out a process of moving at least a pair of lift beams, which are provided in parallel with a work transfer direction, up and down, and a process of reciprocatingly moving a cross bar, which is laterally spanned between the carriers at least a pair of which are provided at each pair of lift beams to oppose each other, moves each pair of carriers along a longitudinal direction of the lift beam, and is provided with work holding means capable of holding a work, based on a predetermined feed motion, and
 
at a time of moving the carriers, by utilizing movement of at least a pair of carriers out of the carriers, moving the cross bar, which is laterally spanned between the utilized pair of carriers, to a position that is offset in a moving direction of the utilized pair of carriers with respect to a moved position of the utilized pair of carriers.
   

     According to the above method, at least a pair of lift beams are individually moved up and down, and the carriers provided at the lift beams are individually moved in the longitudinal direction of the lift beam (work transfer direction). At least a pair of carriers opposing each other moves the cross bar, which is laterally spanned between both the carriers, and is provided with the work holding means capable of holding the work, in the carrier moving direction by utilizing the movement of the carriers when the carriers moving. As a result, rising and lowering stoke and the feed stroke in the transfer direction can be adjusted for each of the lift beams. Consequently, the rising and lowering stroke and the feed stroke in the transfer direction of the cross bar can be adjusted for each area between the adjacent working stations, and the timing of feed motion can be changed, thus making it possible to perform work transfer even in the case in which the transfer pitches between the working stations differ, and making it possible to set a die interference curve corresponding to a die for each area between the working stations. An origin position (feed level) of each working station can be set at a position corresponding to the die. As a result, an optimal die can be designed. Even in the case in which there is a process with a longer transfer pitch than the others between a plurality of working stations, work transfer can be performed without providing an idle station and the length of the entire transfer press line can be made shorter. 
     Further, since offset of the cross bar is driven by utilizing the movement of the carriers at the time of moving the carriers, a driving source for offset drive is not necessary, and the number of components of the carrier is small, thus making it possible to reduce the weight and size. Since at least a pair of carriers move the cross bar to the position that is offset from the carrier moved position, the carrier is moved near to the end portion in the longitudinal direction of the lift beam. As a result, the cross bar can be moved to the position past the end portion in the longitudinal direction of the lift beam. Accordingly, even when a plurality of lift beams are linearly placed along the work transfer direction (longitudinal direction of the lift beam) so that there is no overlapping spot, the cross bar and the work holding means can be moved to substantially the central position of the working station provided between the adjacent lift beams. Consequently, the feed stroke can be set without being restricted by the length of the cross bar, and the length of the cross bar can be constituted to be short. 
     In the work transfer method for the transfer press, the offset position is a position in which the cross bar, which is laterally spanned between the utilized pair of carriers, exceeds end portions of the lift beams, which are provided at the utilized pair of carriers, outward, when the utilized pair of carriers are moved to substantially the end portions in a longitudinal direction of the lift beams. 
     According to the above method, the following effects are further provided other than the effects according to the above-described method. The carrier movable to substantially the end portion in the longitudinal direction of the lift beam offsets the sub-carrier provided at the carrier when the carrier moves to the end portion. As a result, the cross bar is moved to the position in which the cross bar exceeds the end portion of the lift beam outward. Consequently, a plurality of lift beams are placed subsequently in line in the work transfer direction, and even in the case in which the working station exists between the adjacent lift beams, transfer to the working station can be performed with reliability, and limitation in the transfer pattern is eliminated. For example, when a carrying-in device, carrying-out device or the like is placed at the upstream side or the downstream side of the working station, work transfer can be performed correspondingly to various kinds of carrying-in devices and carrying-out devices without being limited by the length of the lift beam in the transfer direction. Therefore, the degree of freedom of the process design of the transfer press line is increased. 
     A first aspect of the work transfer apparatus for the transfer press according to the present invention has the constitution including at least a pair of lift beams provided in parallel with a work transfer direction to be movable up and down, carriers at least a pair of which are provided at each pair of lift beams respectively, and which are movable along a longitudinal direction of the lift beam, paired sub-carriers which are provided along guides provided on at least a pair of the carriers out of the carriers at least a pair of which are provided thereat respectively and are movable in a carrier moving direction, power transmission means which utilizes movement of each pair of carriers when they are moved, and transmits carrier driving force to each pair of sub-carriers, respectively, and a cross bar which is laterally spanned between each pair of sub-carriers opposing each other, and is provided with work holding means capable of holding a work. 
     According to the first constitution, at least a pair of lift beams are individually moved up and down, and the carriers provided at the lift beams are individually moved in the longitudinal direction of the lift beam (work transfer direction). The sub-carriers provided at the carriers are moved in the carrier moving direction via the power transmission mechanism by utilizing the movement of the carriers at the time of moving the carriers. Thereby, it is possible to adjust the rising and lowering stroke and the feed stroke in the transfer direction of the cross bar which is laterally spanned between a pair of sub-carriers opposing each other and is provided with the work holding means capable of holding a work. 
     Consequently, the rising and lowering stroke and the feed stroke in the transfer direction of the cross bar can be adjusted for each area between the adjacent working stations, and the timing of the feed motion can be changed. Accordingly, the work transfer can be performed even in the case in which the transfer pitches between the working stations differ, and the die interference curve corresponding to the die can be set for each area between the working stations. The origin position (feed level) of each of the working stations can be set at the position corresponding to the die. Accordingly, work transfer can be performed without providing an idle station, the length of the entire transfer press line can be made short, and an optimal die can be designed. 
     Further, the carrier driving force is transmitted to the sub-carrier via the power transmission means by utilizing the movement of the carrier when the carrier is moved. As a result, the sub-carrier and the cross bar can be moved by being offset from the carrier, and therefore a driving source for driving the sub-carrier is necessary, thus making it possible to reduce the weight and size of the carrier and sub-carrier. Since the carrier moves the sub-carrier and the cross bar to the position that is offset from the carrier moved position, the cross bar can be moved to the position past the end portion in the longitudinal direction of the lift beam as in the explanation of the above-described method. Consequently, the feed stroke can be set without being restricted by the length of the cross bar, and therefore it can be constituted that the process design is facilitated and the length of the cross bar is made short. 
     A second aspect of the work transfer apparatus for the transfer press according to the present invention has the constitution in which “carriers which are movable along the longitudinal direction of the lift beam” in the first constitution is made “carriers which are driven by the linear motor to be movable along the longitudinal direction of the lift beam”. 
     In the above second constitution, the drive means of the carrier in the first constitution is made a linear motor. As the effects according to this, the driving source of the carrier can be reduced in size and weight, and vibration resistance can be improved. The other effects are the same as the effects in the first constitution. 
     Further, in the work transfer apparatus for the transfer press, the cross bar may be laterally spanned directly between another pair of carriers out of the carriers at least a pair of which are provided thereat respectively. 
     The above constitution is applicable to the case in which the transfer pitch between the working stations is larger than the transfer pitch between the other working stations. For example, in the working station (W 1 ) at the uppermost stream side of the transfer press, a blank material is worked, and therefore the size of the die becomes larger as compared with the sizes of the dies of the following processes. Accordingly, the transfer pitch between the working station (W 1 ) and the working station (W 2 ) becomes larger than the transfer pitches between the working stations of the following processes. In this case, a pair of carriers including the sub-carriers between which the cross bar is laterally spanned and opposing each other are provided in the transfer area between the working stations with the larger transfer pitch. As a result, a larger feed stroke can be set than in the transfer areas between the other working stations provided with the carriers between which the cross bar is directly spanned laterally, and therefore it is possible to design an optimal die in consideration of the die interference curve. 
     A pair of carriers opposing each other and including the sub-carriers between which the cross bar is laterally spanned are provided only the lift beams corresponding to the working station in need of them as described above, whereby the cost can be reduced as necessary. Further, in the transfer press in which uprights exist between the working stations, for example, idle stations are provided at the upright parts. In the case in which the transfer to the next working station cannot be performed unless the transfer is performed via the idle station, it is made possible to transfer a work without providing the idle stations by mounting the carriers including the sub-carriers to which the cross bar is connected and making the feed stroke larger. 
     In the work transfer apparatus for the transfer press, the guides may protrude in a carrier moving direction from end portions of the lift beams to guide the sub-carriers, when at least a pair of carriers out of the carriers provided with the sub-carriers are moved up to substantially the end portion in the longitudinal direction of the lift beam. 
     According to the above constitution, when the carriers are moved up to the area in the vicinity of the end portion in the longitudinal direction of the lift beam, the guides for guiding the sub-carriers protrude in the carrier moving direction from the aforementioned end portion of the lift beam. Therefore, the sub-carriers can be moved to the position past the end portion of the lift beam outward with reliability. Consequently, the work transfer can be also performed with reliability in the transfer press in which the adjacent lift beams are spaced in the working transfer direction and the working stations are set at spaces between the lift beams, and therefore general versatility of the present work transfer apparatus (transfer feeder) is large. 
     In the work transfer apparatus for the transfer press, the power transmission means may include a first rack which is provided at the lift beam along the longitudinal direction of the lift beam, a first pinion which is meshed with the first rack and rotatably supported by the carrier, a second rack which is provided at the sub-carrier along the longitudinal direction of the lift beam, a second pinion which is meshed with the second rack and rotatably supported by the carrier, and rotational force transmission means which transmits a rotational force of the first pinion to the second pinion. 
     According to the above constitution, the power transmission means for transmitting the driving force of the carrier to the sub-carrier is constituted by the combination of the racks and pinions, and therefore power transmission can be performed with reliability with a simple constitution. In this situation, the total moving distance of the sub-carrier from the reference point can be obtained by adding up the moving distance of the carrier and the offset distance of the carrier with respect thereto. The off set distance of the sub-carrier with respect to the moving distance of the carrier can be obtained based on the transmission ratio of the power transmission means and the organizational design parameter, and therefore the position of the sub-carrier, that is, the position of the work holding means can be accurately controlled by controlling the moving distance of the carrier. 
     In the work transfer apparatus of the transfer press, the power transmission means may include a rack which is provided at the lift beam along the longitudinal direction of the lift beam, a pinion which is meshed with the rack and rotatably supported by the carrier, a shaft which is provided at the carrier along the longitudinal direction of the lift beam, rotatably supported, and has a male thread on an outer circumference, a nut which is provided at the sub-carrier and screwed in the shaft, and
     rotational force transmission means for transmitting a rotational force of the pinion to the shaft.   

     According to the above constitution, the power transmission means is constituted by gears such as the rack and the pinion, the other rotational force transmission means, the shaft provided with a male thread engraved on its outer circumference and the nut screwed in the shaft, and therefore power transmission can be performed with reliability with a simple constitution. In this constitution, the position of the work holding means can be accurately controlled as in the above-described power transmission means. 
     In the work transfer apparatus for the transfer press, the power transmission means may include a rack which is provided at the lift beam along the longitudinal direction of the lift beam, a pinion which is meshed with the rack and rotatably supported by the carrier, a deformation gear, in which a teeth part of the gear is provided by being engraved on an outer arc portion of a sector, the teeth part is meshed with either the pinion or an idle gear for transmitting a rotational force of the pinion, and a shaft included at a center of the sector arc is rotatably supported at the carrier, a first lever with one end being rotatably attached to the sub-carrier and the other end being rotatably supported at the carrier movably only in an up-and-down direction, and a second lever with one end being fixed to a rotary shaft of the deformation gear and the other end being rotatably attached between both end axes of the first lever by means of a shaft. 
     According to the above constitution, the power transmission means is constituted by the rack, the pinion, the deformation gear which is meshed with the pinion or the idle gear for transmitting the rotational force of the pinion, and the two levers for connecting the sub-carrier, carrier and the deformation gear with pins, and therefore power transmission can be performed with reliability with a comparatively simple constitution. In this constitution, the position of the work holding means can be accurately controlled as in the above-described power transmission means. 
     In the work transfer apparatus for the transfer press, the power transmission means includes a rack which is provided at the lift beam along the longitudinal direction of the lift beam,
     a pinion which is meshed with the rack and rotatably supported by the carrier, a first pulley fixed to the pinion with a same shaft, second pulleys rotatably supported at substantially both end regions of the carrier in the longitudinal direction of the lift beam, and an endless belt which is wound around the first pulley and the second pulleys, and the sub-carrier is connected to the endless belt between the second pulleys.   

     According to the above constitution, the power transmission means is constituted by the rack, the pinion, the first pulley, the second pulley and the endless belt, and therefore power transmission can be made with reliability with a simple constitution. In this situation, the position of the work holding means can be accurately controlled as the above-described power transmission means. In this constitution, the position of the work holding means can be accurately controlled as the above-described power transmission means. 
     A first aspect of a work transfer apparatus for a press according to the present invention may have a constitution, in a work transfer apparatus for a press for transferring a work within the press or between the presses, including at least a pair of lift beams which are placed in parallel with a work transfer direction at left and right with respect to the work transfer direction, and are provided to be movable up and down, carriers at least a pair of which are provided at each pair of lift beams respectively, and which are movable along a longitudinal direction of the lift beam, paired sub-carriers which are provided along guides provided on at least a pair of the carriers out of the carriers at least a pair of which are provided thereat respectively and are movable by a linear motor in a carrier moving direction, and a cross bar which is laterally spanned between each pair of sub-carriers opposing each other, and is provided with work holding means capable of holding a work. 
     According to the above constitution, the sub-carriers are provided to be individually movable in the carrier moving direction, and therefore the moving distance of the cross bar, that is, the work transfer distance can be optionally set by adding up each stroke of the carrier and the sub-carrier. Therefore, by offsetting the sub-carrier with respect to substantially the middle position of the carrier, a longer feed stroke of the cross bar than the feed stroke in the work transfer direction of the carrier single body can be realized. Accordingly, the feed stroke can be also adjusted by the sub-carrier in the work transfer apparatus in which a long lift beam along the entire station is provided, the carriers are connected to each other, and each of the carriers makes the same stroke with the same motion with one feed drive means, and work transfer with the different pitches between the adjacent working stations can be easily performed. 
     Further, by driving the sub-carrier by means of the linear motor, the work transfer apparatus can be reduced in weight and size. Therefore, the capacity of the other driving sources in the work transfer apparatus can be made smaller, the production cost is made low, the chattering of the bars at the time of actuation, stoppage and inching can be reduced, and the durability of each component of the work apparatus can be increased. Further, increase in speed and positional accuracy by the linear motor can be attained, and therefore even when there is a spot with larger transfer pitch between the working stations than the other spots, slaved following can be sufficiently performed, thus making it possible to correspond to a high-speed operation of the press. 
     Further, by dividing the lift beam, the rising and lowering stroke and the feed stroke in the transfer direction of the work holding means and the cross bar can be independently set for each lift beam. Consequently, the rising and lowering stroke and the feed stroke in the transfer direction of the cross bar can be adjusted for each area between the adjacent working stations, and the timing of the feed motion can be changed, thus making it possible to set the work transfer corresponding to the die for each area between the working stations. The origin position (feed level) in the up-and-down direction for each working station can be set at the position corresponding to the die. As a result of this, an optimal die can be designed. 
     A second aspect of the work transfer apparatus for the press has, in a work transfer apparatus for a press for transferring a work within the press or between the presses, a constitution including at least one lift beam, which is placed in parallel with a work transfer direction and at substantially a center in a lateral direction with respect to the work transfer direction, and is made movable up and down, outside a press working area, a carrier at least one of which is provided at each lift beam, and which is movable along a longitudinal direction of the lift beam, a sub-carrier which is provided along a guide provided on each carrier and movable by a linear motor in a carrier moving direction, and work holding means which is provided at each sub-carrier and capable of holding a work, or a cross bar which is provided at each sub-carrier and has the aforementioned work holding means. 
     According to the above constitution, it is the constitution in which “at least one lift beam at substantially a center in a lateral direction with respect to the work transfer direction” is placed instead of “at least a pair of lift beams which are placed at left and right with respect to the work transfer direction”. The same effects can be obtained in the above constitution, and the constitution of the work transfer apparatus can be simplified and made compact. 
     In the work transfer apparatus for the press, the cross bar may be laterally spanned directly between another pair of carriers out of the carriers at least a pair of which are provided thereat respectively. 
     According to the above constitution, the carrier positions out of a plurality of carriers, in which the sub-carriers are provided, may be determined and constituted according to the amount of necessity of the degree of freedom of the die design, the necessity of the large feed stroke and the like. Namely, the work transfer distances can be set optionally by the feed stroke of only the carrier and adding up of the strokes of the carrier and the sub-carrier. For example, there is the case in which the transfer pitch between certain working stations is larger than the transfer pitch between the other working stations. In this case, a pair of carriers opposing each other, which include the sub-carriers between which the cross bar is laterally spanned, are provided in the transfer area between the working stations with the larger transfer pitch. Thereby, a larger feed stroke than in the transfer area between the other working stations provided with the carriers between which the cross bar is directly spanned laterally can be set, and therefore it is possible to design an optimal die. As described above, by providing a pair of carriers opposing each other, which include the sub-carriers between which the cross bar is laterally spanned, only at the lift beams corresponding to the working station in need of them, the cost can be reduced as necessary. 
     In the work transfer apparatus for the press, the guides, which guide the sub-carriers, may protrude in the carrier moving direction from end portions of the lift beams, when at least a pair of (or one of) the carriers are moved up to substantially the end portion in the longitudinal direction of the lift beam. 
     According to the above constitution, when the carrier is moved up to the end portion of the lift beam, the sub-carriers and the cross bar can be moved to the position past outward in the carrier moving direction from the end portion of the lift beam. Consequently, the work transfer distance can be set without being restricted by the length of the lift beam, the process design is facilitated, and the length of the lift beam can be constituted to be small. Further, even in the case in which a plurality of lift beams are placed in series in the longitudinal direction, and the adjoining parts of the adjacent lift beams are located at substantially the center (die) of the working station, the cross bar can be moved to substantially the center of the working station with reliability. 
     A third aspect of the work transfer apparatus for the press has, in a work transfer apparatus for a press for transferring a work within the press or between the presses, a constitution including at least a pair of lift beams which are placed in parallel with a work transfer direction at left and right with respect to the work transfer direction, and are provided to be movable up and down, carriers at least a pair of which are provided at each pair of lift beams respectively, and which are movable along a longitudinal direction of the lift beam, paired sub-carriers which are provided along guides provided on at least a pair of the carriers out of the carriers at least a pair of which are provided thereat respectively, and movable in a carrier moving direction, and a cross bar which is laterally spanned between each pair of sub-carriers opposing each other, and is provided with work holding means capable of holding a work, in which the aforementioned guides, which guide the sub-carriers, protrude in the carrier moving direction from end portions of the aforementioned lift beams, when at least a pair of the carriers are moved up to substantially the end portion in the longitudinal direction of the lift beam. 
     According to the above constitution, even though the drive means for the sub-carrier is not the linear motor, for example when it is the drive of a servo motor, or when the sub-carrier is moved by following the movement of the carrier with use of pulleys and a belt without having an individual driving source of the sub-carrier itself, the same effects as described above can be obtained. 
     A fourth aspect of the work transfer apparatus for the press has, in a work transfer apparatus for a press for transferring a work within the press or between the presses, a constitution including at least one lift beam, which is placed in parallel with a work transfer direction and at substantially a center in a lateral direction with respect to the work transfer direction, and is made movable up and down, outside a press working area, a carrier at least one of which is provided at each lift beam, and which is movable along a longitudinal direction of the lift beam, a sub-carrier which is provided along a guide provided on each carrier and movable in a carrier moving direction, and work holding means which is provided at each sub-carrier and capable of holding a work, in which a guide, which guides the sub-carrier, protrudes in the carrier moving direction from an end portion of the lift beam, when at least one of the carrier is moved up to substantially the end portion in the longitudinal direction of the lift beam. 
     The above constitution is the constitution in which at least one lift beam is placed at substantially the center in the lateral direction instead of at least a pair of lift beams provided at left and right with respect to the work transfer direction in the above-described third constitution. In this case, the same effects as in the third constitution can be obtained and the constitution of the work transfer apparatus can be simplified and made compact. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an entire perspective view schematically showing a transfer press to which the present invention is applied; 
         FIG. 2  is a front view of  FIG. 1 ; 
         FIG. 3  is a sectional plan view of  FIG. 2 ; 
         FIG. 4  is a side view of  FIG. 2 ; 
         FIG. 5  is a front view of sub-carrier moving means according to a first embodiment of the present invention; 
         FIG. 6  is a right side view of  FIG. 5 ; 
         FIG. 7  is an explanatory view of moving distances of a carrier and a sub-carrier of the first embodiment; 
         FIG. 8  is a front view of an essential part of a sub-carrier according to a second embodiment of the present invention; 
         FIG. 9  is a right side view of  FIG. 8 , 
         FIG. 10  is an explanatory view of moving distances of a carrier and the sub-carrier of the second embodiment; 
         FIG. 11  is a front view of an essential part of sub-carrier moving means according to a third embodiment of the present invention; 
         FIG. 12  is a right side view of  FIG. 11 ; 
         FIG. 13  is an explanatory view of moving distances of a carrier and a sub-carrier of the third embodiment; 
         FIG. 14  is a front view of an essential part of sub-carrier moving means according to a fourth embodiment of the present invention; 
         FIG. 15  is a right side view of  FIG. 14 ; 
         FIG. 16  is a sectional plan view of a transfer press according to a fifth embodiment of the present invention; 
         FIG. 17  is a side view of the transfer press showing carriers for T 3  of the fifth embodiment; 
         FIG. 18  is an explanatory view in the vicinity of the carrier for T 3  of  FIG. 17 ; 
         FIG. 19  is an entire perspective view schematically showing a transfer press being another example to which the present invention is applied; 
         FIG. 20  is a front view of  FIG. 19 ; 
         FIG. 21  is a sectional plan view of  FIG. 20 ; 
         FIG. 22  is a side view of  FIG. 20 ; 
         FIG. 23  is a front view of sub-carrier drive means according to a sixth embodiment of the present invention; 
         FIG. 24  is a right side view of  FIG. 23 ; 
         FIG. 25  is another example of the sub-carrier drive means according to a sixth embodiment; 
         FIG. 26  is a front view of a work transfer apparatus according to a seventh embodiment of the present invention; 
         FIG. 27  is a plan view of  FIG. 26 ; 
         FIG. 28  is a side view of  FIG. 26 ; 
         FIG. 29  is another example of sub-carrier drive means according to the seventh embodiment; 
         FIG. 30  is a modified example of the sixth embodiment, and is a side view of a transfer press showing carriers between which a cross bar is directly spanned laterally; and 
         FIG. 31  is an explanatory view of a vicinity of the carrier in  FIG. 30 . 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Preferred embodiments of the present invention will be explained in detail below with reference to the drawings. 
     First, a transfer press will be explained based on  FIG. 1  to  FIG. 4 .  FIG. 1  is an entire perspective view schematically showing the transfer press to which the present invention is applied.  FIG. 2  is a front view of the transfer press in  FIG. 1 , and is a view showing an operation state of a transfer feeder.  FIG. 3  and  FIG. 4  are a sectional plan view and a side view of the transfer press, respectively. In the first to fifth embodiments that will be described later, this transfer press is used. 
     In  FIG. 1  and  FIG. 4 , a transfer press  1  is constituted by arranging a plurality (four in this embodiment) of press units  2 , which are fabricated into a module, along a work transfer direction, and includes working stations W 1  to W 4  corresponding to the respective press units  2 . The transfer press  1  includes a controller  3  as control means having a control panel and an operation panel (both are not shown), a stacker device (not shown) for supplying works, a transfer feeder  10  and the like. In this transfer press  1 , the left side of the drawings is an upstream of transfer of a work  11 , and a right side is a downstream of the transfer. 
     Each of the press units  2  constituting the transfer press  1  includes a crown  4 , in which a slide driving force transmission mechanism is incorporated, a slide  5 , which is connected to the aforementioned slide driving force transmission mechanism via a plunger  5 A and is mounted with an upper die (not shown), and a bed  6  provided with a bolster  6 A mounted with a lower die (not shown). As for the bolster  6 A, a moving bolster, or an ordinary bolster fixed to the bed  6  can be used. 
     Each of a pair of uprights  7  and  7  are vertically provided between the adjacent press units  2  and  2 , and at end portions of the press units  2  at the uppermost stream side and the lowermost stream side in the work transfer direction to oppose each other laterally with respect to the work transfer direction in the plan view. A tie rod  8  for firmly connecting the crown  4 , the bed  6  and the upright  7  vertically penetrates inside each of the uprights  7 . As shown in  FIG. 1  and  FIG. 4 , each of the slides  5  is driven by a slide drive section  20  having a main motor  21  provided at each of the press units  2 , a fly wheel  22  rotationally driven by the main motor  21  and the like. 
     The controller  3  includes an arithmetic unit such as a microcomputer and high-speed numeric processor, and controls each of the slide drive sections  20  to drive the slide  5 . In addition, the controller  3  controls each lift drive means, carrier drive means and work holding means that will be described later to drive the transfer feeder  10 . The controller  3  includes W 1  to W 4  control means  3 A to  3 D each for controlling the slide drive section  20  for each of the press units  2 , and general control means  3 E for generally controlling the W 1  to W 4  control means  3 A to  3 D. Each of the W 1  to W 4  control means  3 A to  3 D has the equivalent function to the control means of an ordinary single press, and controls the slide drive section  20  of the corresponding working station W 1  to W 4  irrespective of the other slide drive sections  20  to drive each of the slides  5  independently. 
     The general control means  3 E controls the W 1  to W 4  control means  3 A to  3 D corresponding to each of the slides  5  according to a work working process and each slide motion corresponding to it, and thereby it controls the slide drive section  20  of the working stations (W 1  to W 4 ) corresponding to the respective control means  3 A to  3 D to drive the slides  5  synchronously with each other. The controller  3  includes T 1  to T 4  control means  3 F to  3 I for controlling the transfer feeder  10 , and the T 1  to T 4  control means  3 F to  3 I controls four feed units  12  that will be described later. 
     Next, the transfer feeder  10  will be explained. The transfer feeder  10  successively transfers the work  11  worked in each of the working stations W 1  to W 4  to the downstream side in transfer areas T 1  to T 4  which are set along the adjacent working stations W 1  to W 4  and set at the downstream side of the final working station (W 4  in this case). Accordingly, the transfer feeder  10  is constituted by four of the feed units  12  each disposed inside the transfer areas T 1  to T 4  as shown in  FIG. 2  and  FIG. 3 . 
     Each of the feed units  12  includes the following components. Namely, first of all, it includes a pair of left and right lift beams  13  and  13  (corresponding to conventional transfer bars) movable up and down, which are disposed in parallel along the work transfer direction and spaced in a horizontal direction so as not to interfere with the slide motion. At upper portions of a pair of the left and right lift beams  13  and  13 , provided are lift drive means having lift shaft servo motors  14  and  14  for driving the lift beams  13  and  13  up and down. By outputting a control signal to the aforementioned lift drive means from corresponding one of the T 1  to T 4  control means  3 F to  3 I, the lift beam  13  is driven to move up and down. At lower portions of the lift beams  13  and  13 , provided are carriers  15  and  15  to be movable in a longitudinal direction of the lift beam  13 . At an upper portion of each of the carriers  15  and  15 , included is carrier drive means having linear motors  16  and  16  (see  FIG. 6 ) for driving each of the carriers  15  in the longitudinal direction of the lift beam  13 . Carrier movement is controlled by outputting a control signal to the aforementioned carrier drive means from corresponding one of the T 1  to T 4  control means  3 F to  3 I. 
     Further, sub-carriers  50  and  50  (details will be described later) are provided at a lower portion of the respective carriers  15  and  15  to be movable in the longitudinal direction of the lift beam  13 . Power transmission means for transmitting driving force of the carrier  15  to the sub-carrier  50  is provided between the carrier  15  and the sub-carrier  50  at the lower portion thereof. A cross bar  17  is spanned between the sub-carriers  50  and  50  provided at a pair of the left and right carriers  15  and  15  opposing each other. The cross bar  17  is provided with a vacuum cup device  18  capable of sucking, for example, the work  11  at a predetermined number of spots (four spots in this embodiment) as the work holding means. A control signal is inputted into the vacuum cup device  18  of each of the cross bars  17  from corresponding one of the T 1  to T 4  control means  3 F to  3 I, whereby the operation of suction is controlled. 
     Next, sub-carrier moving means of the work transfer apparatus according to the first embodiment will be explained in detail based on  FIG. 5  and  FIG. 6 .  FIG. 5  is a front view of the sub-carrier moving means of this embodiment, and  FIG. 6  is a right side view of  FIG. 5 . 
     As shown in  FIG. 5  and  FIG. 6 , the linear motor  16  is placed along the work transfer direction between the lift beam  13  and the carrier  15 , and linear guides  19  and  19  are placed along the work transfer direction at both sides of the linear motor  16 . A guide rail  19   a  of each of the linear guides  19  is attached at a bottom surface of the lift beam  13  and a guide member  19   b  of the linear guide  19  is attached at a top surface of the carrier  15 . The guide member  19   b  is slidably engaged with the guide rail  19   a  in a state in which it is suspended from the guide rail  19   a.  Each of the linear motors  16  enables each of the carriers  15  to be self-propelled independently along the linear guides  19 . Any one of a primary coil  16   a,  and a secondary conductor  16   b  or a secondary permanent magnet, which constitute the linear motor  16 , is laid on the lift beam  13  side and the other one is laid on the carrier  15  side to oppose the aforementioned one of them. The carrier  15  can be made to travel at an optional speed along the linear guides  19  by inputting a control signal into the primary coil  16   a  from the corresponding one of the T 1  to T 4  control means  3 F to  3 I. 
     As shown in  FIG. 6 , a transverse section in the longitudinal direction of the lift beam  13  is substantially a rectangular shape, and a rack  51  is attached along a laterally outer surface of the lift beam  13  by means of a bonding member  52 . A tooth portion of the rack  51  is provided to be substantially parallel with the bottom surface of the lift beam  13 . Meanwhile, as shown in  FIG. 5 , a pinion shaft  53  is rotatably supported at substantially a center part of the carrier  15  with its shaft axis orthogonal to the moving direction of the carrier  15 . A first pinion  54  is attached to one end portion of the pinion shaft  53 , and it is provided so that the first pinion  54  and the rack  51  are meshed with each other. Further, a second pinion  55  is attached to the other end portion of the pinion shaft  53 . 
     A frame  56  of the sub-carrier  50  is placed under the carrier  15 . Linear guides  57  and  57  are provided at both sides along the longitudinal direction at the lift beam  13  at the bottom surface of the carrier  15 . A guide rail  57   a  of the linear guide  57  is attached to the bottom surface of the carrier  15 , and a guide member  57   b  of the linear-guide  57  is attached to a top surface of the frame  56 . The guide member  57   b  is slidably engaged with the guide rail  57   a  in a state in which it is suspended from the guide rail  57   a.  The sub-carrier  50  is moved by being guided by the linear guide  57 . A rack  58  is attached to the top surface of the frame  56  in parallel with the linear guide  57  so as to be meshed with the second pinion  55 . 
     Next, an operation of the sub-carrier moving means of the above-described constitution will be explained. When the carrier  15  is driven by the linear motor  16 , the carrier  15  is moved in the longitudinal direction of the lift beam  13 . At the same time, the pinion shaft  53  is also moved in the same direction as the carrier  15 , and by this movement, the first pinion  54  is meshed with the rack  51  to follow its motion to rotate, thus rotating the second pinion  55  at the same time via the pinion-shaft  53 . When the second pinion  55  is rotated, with this rotation as a driving source, the sub-carrier  50  including the rack  58  meshed with the second pinion  55  is driven. Accordingly, the sub-carrier  50  moves longer distance than the moving distance of the carrier  15  to the moving direction of the carrier  15 . Namely, the sub-carrier  50  is moved to a position offset from the moved position of the carrier  15 . 
     Here, based on  FIG. 7 , the moving distances of the carrier  15  and the sub-carrier  50  will be explained. In  FIG. 7 , when the carrier  15  is moved in a direction of the arrow A 1  by the linear motor  16 , the first pinion  54  is rotated in a direction of the arrow A 2 . Here, the present position before the carrier  15  is moved is set as a reference point. When a moving distance by which the carrier  15  moves to the upstream side or the downstream side from this reference point is assumed to be Lm, rotational frequency N of the first pinion  54  by the movement of the carrier  15  is N=Lm/(π×D 1 ). Here, it is assumed that D 1  is a diameter of a pitch circle of the first pinion  54 , and that the dimensions of the modules of the first pinion  54  and the second pinion  55  are the same. When a distance by which the rack  58  and the sub-carrier  50  move in the direction of the arrow A 1  with respect to the carrier  15  as a result of the second pinion  55  makes N rotations similarly to the first pinion  54  is assumed to be Lt, Lt=N×π×D 2 =Lm×(D 2 /D 1 ). Here, D 2  is a diameter of the pitch circle of the second pinion  55 . 
     Accordingly, a total moving distance L of the sub-carrier  50  at which the rack  58  is attached before it is moved is found by adding up the moving distance Lm of the carrier  15  from the reference point to a movement completion position and the moving distance Lt of the sub-carrier  50  with respect to the carrier to be L=Lm+Lt. Namely, the moving distance Lt is an offset amount-of the sub-carrier  50  with respect to the carrier  15 , and is obtained from the moving distance Lm of the carrier  15  based on a diameter ratio of the pitch circles of the first pinion  54  and the second pinion  55  (D 2 /D 1 ), namely, the power transmission attenuation ratio such as a gear ratio. 
     Next, with reference to  FIG. 2  and  FIG. 3 , a transfer method of the work  11  by the transfer feeder  10  of the above constitution will be explained. First, when working in the working station W 1  is finished and the slide  5  starts to rise in the transfer area T 1 , the carrier  15  of the lift beam  13  at a position of predetermined height is moved toward an end portion of the working station W 1  side along the lift beam  13 . Following the movement of the carrier  15 , the sub-carrier  50  is moved to a position past the moved position of the carrier  15  by a predetermined offset amount Lt corresponding to the moving distance Lm of the carrier  15  in the same moving direction as the carrier  15  (see the carrier  50 A and the cross bar  17 A shown by the chain double-dashed line in  FIG. 2  and  FIG. 3 ). As a result, the vacuum cup device  18  is positioned at a work suction position in the working station W 1 . Next, at this position, the lift beam  13  is lowered to suck the work  11 . 
     Thereafter, the lift beam  13  is raised, and the carrier  15  is moved to the downstream side, namely, an end portion at the side of the working station W 2 , whereby the sub-carrier  50  is similarly moved in the downstream direction. Then the sub-carrier  50  is moved to a position offset to the working station W 2  by a predetermined distance from the moved position of the carrier  15  (see the sub-carrier  50 B and the cross bar  17 B shown by the chain double-dashed line in  FIG. 2  and  FIG. 3 ). Thereby, the vacuum cup device  18  is positioned at the work suction position of the working station W 2 . Subsequently, the lift beam  13  is lowered at this position and the work  11  is released. Next, before the slide  5  of the working station W 2  is not completely lowered, namely, before press working starts in the working station W 2 , the lift beam  13  is raised. Namely, the carrier  15  is returned to substantially the central position of the transfer area T 1  so that the sub-carrier  50  and the cross bar  17  do not interfere with the slide  5  and the die. 
     Subsequently, when working in the working station W 2  is finished, the sub-carrier  50  is driven by the movement of the lift beam  13  and the carrier  15  in the transfer area T 2  as the feed unit  12  of the transfer area T 1 . The respective feed units  12  are similarly driven in the transfer areas T 3  and T 4 , whereby the work is carried in and out in all the transfer areas T 1  to T 4 , and it is finally transferred to a transfer apparatus or the like not shown from the transfer area T 4 . Actually, the carrier  15  and the sub-carrier  50  are not moved in a state in which the lift beam  13  is standing still, but they are moved while the lift beam  13  is moved up and down. As a result, efficient transfer with simultaneous drive of the driving shaft can be performed, and working speed (operation strokes per minute) can be enhanced. 
     As explained above, the following effects are provided according to the first embodiment. 
     (1) In the transfer press having a plurality of working stations, a pair of lift beams  13  and  13  corresponding to each area between the adjacent working stations are provided in parallel along the work transfer direction to be movable up and down. The respective lift beams  13  and  13  are provided with the carriers  15  and  15  driven along the longitudinal direction by the predetermined drive means. Further, the carriers  15  and  15  are provided with the sub-carriers  50  and  50  to be movable in the longitudinal direction of the lift beam  13 . In addition, the driving force of the sub-carriers  50  and  50  are obtained by the power transmission mechanism utilizing the movement of the carriers  15  and  15 , and the cross bar  17  provided with the work holding means such as the vacuum cup device  18  is spanned between a pair of opposing sub-carriers  50  and  50 . In this constitution, by adjusting the moving distance Lm of the carriers  15  and  15  corresponding to each area between the working stations, a feed stroke L of the sub-carriers  50  and  50  and the cross bar  17  can be adjusted for each area between the working stations. As a result, work transfer can be also performed with reliability in the transfer press in which the transfer pitches between the adjacent working stations are different. Accordingly, as compared with the prior art in which all the transfer pitches are designed to conform to the maximum transfer pitch, the length of the transfer press line can be designed to be optimally short. Even with the transfer press in which the uprights exist between the working stations, the work can be directly transferred to the next working station without providing idle stations at the part of the uprights and therefore the entire transfer press line including all the working stations can be reduced. 
     (2) The rising and lowering stroke of the lift beam  13  and the feed stroke of the cross bar can be adjusted for each working station, and therefore timing of the feed motion of the work holding means can be adjusted for each of the working stations. Accordingly, a die interference curve corresponding to the attached die can be set. Further, the origin position (feed level) for each working station can be set at the position corresponding to the dies. Accordingly, the interference curve corresponding to a die can be set for each process, and optimal die design can be made. 
     (3) The sub-carrier  50  made movable along the carrier  15  is moved to the position offset from the center part of the lift beam  13  toward the end portion from the moved position of the carrier  15 . Therefore, as shown in  FIG. 5 , the work holding means of the cross bar  17  can be moved past the both end portions of the lift beam  13  to the position overlapping the adjacent lift beam  13 . Consequently, even with the constitution in which the conventional one transfer bar is divided and a plurality of lift beams  13  are arranged substantially in line in the work transfer direction, the constraint of the work transfer distance by this is eliminated, and the degree of freedom in setting the feed motion of the work holding means can be increased. 
     (4) Since the carrier driving force is transmitted to the sub-carrier  50  by utilizing the power occurring when the carrier  15  is moved, the drive source for the sub-carrier  50  is not needed, and the constitution can be made compact. Since the rack and the pinion are used as the power transmission means for transmitting the driving force of the carrier  15  to the sub-carrier  50 , it can be transmitted with reliability, and the constitution of the carrier  15  and the sub-carrier  50  is simple, and can be made compact. 
     (5) Since the linear motor  16  is used as the drive means for moving the carrier  15 , the drive source can be reduced in weight and size, and has a structure resistant to vibrations. 
     Next, sub-carrier moving means according to a second embodiment will be explained based on  FIG. 8  to  FIG. 10 .  FIG. 8  is a front view of an essential part of the sub-carrier moving means, and  FIG. 9  is a right side view of  FIG. 8 . 
     In  FIG. 8  and  FIG. 9 , the linear motor  16  is attached between the lift beam  13  and the carrier  15 , the carrier  15  is moved along the longitudinal direction of the lift beam  13  with the linear motor  16  as a driving source, and the linear guide  19  as a guide. The first pinion  54  is attached to one end portion of the pinion shaft  53  rotatably provided at the carrier  15 , and the first pinion  54  and the rack  51  provided at the lift beam  13  are meshed with each other. The frame  56  of the sub-carrier  50  is placed under the carrier  15 . The linear guides  57  and  57  are placed at both sides along the longitudinal direction at the lift beam  13  at the bottom surface of the carrier  15  so that the sub-carrier  50  can be independently moved by being guided by the linear guides  57  and  57 . 
     Further, an input side bevel gear  61   a  is attached to the other end portion, and an output side bevel gear  61   b  meshed with the bevel gear  61   a  is attached to one end portion of a shaft  62 . The shaft  62  is rotatably supported at a bevel gear box  61  in which a pair of bevel gears  61   a  and  61   b  are equipped. The bevel gear box  61  is attached at the carrier  15 . The shaft  62  is placed along the longitudinal direction of the lift beam  13 , and a gear  63   a  is attached to the other end portion of the shaft  62 . A nut  65  is attached at the top surface of the frame  56  of the sub-carrier  50 , and a shaft  64  (ball screw or the like) having a male thread on its outer circumference provided along the longitudinal direction of the lift beam  13  is screwed into the nut  65 . A second pinion  63   b  meshed with the gear  63   a  is attached to an end portion of the shaft  64  at the opposite side of the nut  65 . The region of the shaft  64  near the second pinion  63  is rotatably supported by the carrier  15 . 
     An operation of the sub-carrier moving means of this embodiment is as follows. When the carrier  15  is driven by the linear motor  16 , the pinion shaft  53  is moved with the carrier  15 , and the first pinion  54  is meshed with the rack  51  to follow its movement to rotate. As a result, the input side bevel gear  61   a  is simultaneously rotated via the pinion shaft  53 , and the gear  63   a  is rotated via the output side bevel gear  61   b  meshed with the bevel gear  61   a.  When the gear  63   a  is rotated, with this rotation as a driving source, the shaft  64  is rotated via the second pinion  63   b,  whereby the sub-carrier  50 , at which the nut  65  screwed into the shaft  64  is attached, is moved along the longitudinal direction of the lift beam  13 . Accordingly, the sub-carrier  50  is moved to the position offset from the moved position of the carrier  15 . 
     Here, the moving distances of the carrier  15  and the sub-carrier  50  will be explained with reference to  FIG. 10 . In  FIG. 10 , when the carrier  15  is moved in the direction of the arrow A 3  by the linear motor  16 , the first pinion  54  is rotated in the direction of the arrow A 4 . Here, the present position before the carrier  15  moves is assumed to be a reference point. When the moving distance by which the carrier  15  moves from the reference point to the upstream side or the downstream side is assumed to be Lm, the rotational frequency N 1  of the first pinion  54  by the movement of the carrier  15  is N 1 =Lm/(π×D 1 ). Here, D 1  is the diameter of the pitch circle of the first pinion  54 . 
     When the distance by which the sub-carrier  50  is moved in the direction of the arrow A 3  that is the same direction as the carrier  15  with the movement of the carrier  15  as a driving source is assumed to be Lt, Lt=Ns×Ls=[Lm/(π×D 1 )]×i×[D 3 /D 4 ]×Ls. Here, i represents the rotational frequency ratio of the bevel gears  61   a  and  61   b,  Ls represents a lead of the male thread of the shaft  64 , D 3  and D 4  represent the diameters of the pitch circles of the gear  63   a  and the second pinion  63   b,  and the dimensions of the modules of the gear  63  and the pinion are assumed to be the same. 
     Accordingly, the total moving distance L from the time before the sub-carrier  50  moves is L=Lm+Lt. Namely, the moving distance Lt is an offset amount of the sub-carrier  50  with respect to the carrier  15 , and can be obtained from the moving distance Lm of the carrier  15  based on the power transmission ratio from the carrier  15  to the sub-carrier  50  such as the pitch circle diameter D 1  of the first pinion  54 , the rotational frequency ratio i of the bevel gears  61   a  and  61   b,  the diameter ratio (D 3 /D 4 ) of the pitch circles of the gear  63   a  and the second pinion  63   b,  namely, the gear ratio, and the lead Ls of the male thread of the shaft  64 . The moving distance of the carrier  15  can be controlled by controlling the moving amount of the linear motor  16  driving along the lift beam. 
     The effects according to the second embodiment will be explained. In the second embodiment, the power transmission means for transmitting the driving force of the carrier  15  to the sub-carrier  50  is constituted by the rack  51  and the pinion  54 , the bevel gears  61   a  and  61   b,  the shaft  64  having the male thread on its outer circumference, the nut  65  and the like. As a result, power transmission can be carried out with reliability, and the power transmission means can be made compact with a simple structure. The other effects are the same as the first embodiment, and the explanation thereof will be omitted. 
     Next, sub-carrier moving means according to a third embodiment will be explained based on  FIG. 11  to  FIG. 13 .  FIG. 11  is a front view of an essential part, and  FIG. 12  is a right side view of  FIG. 11 . 
     In  FIG. 11  and  FIG. 12 , the linear motor  16  is attached between the lift beam  13  and the carrier  15 , and with the linear motor  16  as a driving source, and the linear guide  19  as a guide, the carrier  15  is moved along the longitudinal direction of the lift beam  13 . The constitution of the sub-carrier moving means at both side surface portions of the carrier  15  are the same, and therefore the constitution at only one side will be explained hereinafter. The pinion shaft  53  is rotatably provided at the side surface of the carrier  15 , and the pinion  54  is attached at an outer side end portion of the pinion shaft  53 . A deformation gear  71  having gear teeth on its sector circumference portion is attached to the carrier  15  with a shaft  74  provided at a center part of a sector arc thereof being rotatably supported at the carrier  15 . The gear at the outer circumference portion of the deformation gear  71  is meshed with an idle gear  53   a  attached at the pinion shaft  53 . 
     Brackets  15   b  protruding upward are attached at top portions of substantially a center of both side surfaces of the carrier  15 , and a grooves  15   a  each in a concave shape extending in substantially a vertical direction are formed on outer side surfaces of the brackets  15   b.  A roller  72   a  rotatably provided at one end of a lever  72  is rollably inserted in the groove  15   a  in a concave shape with both side surfaces of the groove  15   a  as rolling contact surfaces, and the other end portion of the lever  72  is rotatably connected to the sub-carrier  50  with a pin. 
     One end portion of a lever  73  is fixed to a rotation center shaft  74  of the deformation gear  71 , and the other end portion of the lever  73  is rotatably connected to a middle portion between both end axes of the lever  72  with a shaft  75 . A distance between both shafts  74  and  75  of the lever  73  and a distance between the shaft  75  and a rotation axis of the roller  72   a  at the lever  72  are constituted to be equal. The frame  56  of the sub-carrier  50  is placed under the carrier  15 . The linear guides  57  and  57  are placed at both sides of the bottom surface of the carrier  15  along the longitudinal direction of the lift beam  13  so that the sub-carrier  50  can be independently self-propelled by being guided by the linear guides  57  and  57 . 
     Next, an operation of the sub-carrier moving means of the third embodiment will be explained. When the carrier  15  is driven by the linear motor  16 , the pinion shaft  53  is moved with the carrier  15 , and the pinion  54  is meshed with the rack  51  to follow its movement to rotate. As a result, the deformation gear  71  meshed with the idle gear  53   a  attached to the pinion shaft  53  is simultaneously rotated, and the lever  73  attached at the rotation center shaft  74  is rotated. By the rotation of the lever  73 , the shaft  75  is moved in the same moving direction as the carrier  15  to move the lever  72 , and therefore the roller  72   a  rolls inside the groove  15   a  to move up and down. Then, the sub-carrier  50  is moved in the same moving direction as the carrier  15  by being guided by the linear guides  57  and  57 . Accordingly, the sub-carrier  50  is moved to a position offset from the moved position of the carrier  15 . 
     Here, the moving distances of the carrier  15  and the sub-carrier  50  will be explained with reference to  FIG. 13 . When the carrier  15  is moved in the direction of the arrow A 5  by the linear motor  16 , the pinion  54  is rotated in the direction of the arrow A 6 , and the deformation gear  71  is rotated in the direction of the arrow A 7 . The lever  73  is also rotated integrally with the rotation of the deformation gear  71  with the shaft  74  as a center, and the roller  72   a  of the lever  72  rolls, downward inside the concave-shaped groove  15   a.  The sub-carrier  50  at the other end portion of the lever  72  and the cross bar  17  are guided by the linear guide  57  to be moved in the same direction as the arrow A 5 . 
     Now, the distance between both the shafts  74  and  75  of the lever  73  and the distance between the shaft  75  and the rotation axis of the roller  72   a  are equally set to be L 1 , and the distance between the shaft  75  at the lever  72  and a connecting axis of the lever  72  with the carrier  50  is set to be L 2 . In each of the transfer areas T 1  to T 4 , the middle position in a movable range of the carrier  15  is set to be a reference point, and at the position of this reference point, both the lever  72  and the lever  73  are assumed to be upright in the vertical direction seen from the front in  FIG. 11 . A moving distance by which the carrier  15  moves from the reference point to the upstream side or the downstream side is set to be Lm, the diameter of the pitch circle of the pinion  54  is D 1 , the diameter of the pitch circle of the idle gear  53   a  is D 7 , and the diameter of the pitch circle of the deformation gear  71  is D 5 . 
     When the carrier  15  moves by the distance Lm from the reference point, the distance Lt by which the sub-carrier  50  moves is found from Lt=(L 1 +L 2 )×sin [2×D 7 ×Lm/(D 1 ×D 5 )] from the mechanical relationship. Accordingly, the moving distance L of the sub-carrier  50  at this time is L=Lm+Lt. Namely, the moving distance Lt is an offset amount of the sub-carrier  50  with respect to the carrier  15 , and it is obtained from the moving distance Lm of the carrier  15  based on the mechanical parameter from the carrier  15  to the sub-carrier  50  as described above. It is the same as the above description that the moving distance of the carrier  15  can be controlled by controlling the moving amount of the linear motor  16  driving along the lift beam. 
     The effects according to the third embodiment will be explained. In the third embodiment, the power transmission means for transmitting the driving force of the carrier  15  to the sub-carrier  50  is constituted by the rack  51  and the pinion  54 , the deformation gear  71 , the lever  73  with the moving direction of its end portion being restricted to be the vertical direction and the moving direction of the sub-carrier  50 , the lever  72  attached to the rotation shaft  74  of the deformation gear  71 , and the like, and therefore power transmission can be carried out with reliability. Since the other effects are the same as in the first embodiment, the explanation is omitted here. 
     Next, sub-carrier moving means according to a fourth embodiment will be explained based on  FIG. 14  and  FIG. 15 .  FIG. 14  is a front view of an essential part, and  FIG. 15  is a right side view of  FIG. 14 . 
     In  FIG. 14  and  FIG. 15 , the pinion shaft  53  is rotatably provided at substantially a center part of the side surface of the carrier  15 , and the pinion  54  is attached at an outer side end portion of the pinion shaft  53 . A pulley  81  is attached at the other end portion of the pinion shaft  53 . Pulleys  82  and  82  are rotatably provided at both front and rear end portions of the carrier  15  in the longitudinal direction of the lift beam  13  (namely, the work transfer direction), and an endless belt  83  such as a timing belt is wound around the pulley  81  and pulleys  82  and  82 . A sub-carrier  50  is attached to a lower belt of the endless belt  83  between the front and rear pulleys  82  and  82 . An upper belt of the endless belt  83  is wound around the pulley  81 , and predetermined tension is given to the endless belt  83  with tension pulleys  84  and  84  provided in the vicinity of the areas in front and behind the pulley  81 . 
     An operation according to the above constitution will be explained. When the carrier  15  is moved by the linear motor  16 , the pinion  54  is meshed with the rack  51  to be rotated, and the pulley  81  at the same shaft is rotated, thus rotating the endless belt  83 . By the rotation of the endless belt  83 , the sub-carrier  50  is moved along the longitudinal direction of the lift beam  13  with the linear guide  57  as a guide. As shown in  FIG. 14 , when the carrier  15  is moved in the direction of the arrow A 8 , the pinion  54  and the pulley  81  at the same shaft as this are rotated in the direction of the arrow A 9 , and therefore the endless belt  83  moves the sub-carrier  50  in the direction of the arrow A 8  which is in the same direction as the carrier  15 . Accordingly, the sub-carrier  50  is moved to the position offset from the moved position of the carrier  15 . 
     The moving distances of the carrier  15  and the sub-carrier  50  will be explained based on  FIG. 14 . In the transfer areas T 1  to T 4 , the position, in which the position of the pinion  54  of the carrier  15  and the attachment position of the sub-carrier  50  to the endless belt  83  are equal in the transfer direction, is assumed to be a reference point. If the moving distance from the reference point (work transfer distance) is made equal in the longitudinal direction, the reference point is the middle position in the movable range of the carrier  15 . When the moving distance by which the carrier  15  moves from this reference point to the upstream or the downstream side is assumed to be Lm, the rotational frequency N of the pinion  54  by the movement of the carrier  15  is N=Lm/(π×D 1 ). Here, D 1  represents a diameter of the pitch circle of the pinion  54 . 
     When the pinion  54  makes N rotations, the pulley  81  also makes N rotations, and therefore if the distance, by which the endless belt  83  and the sub-carrier  50  are moved in the direction of the arrow A 8  by the N rotations of the pulley  81 , is assumed to be Lt, Lt=N×π×D 6 =Lm×D 6 /D 1 . Here, D 6  represents a diameter of an outer circumference surface of the pulley  81 . Thus, by selecting the diameter ratio of the pitch circle of the pinion  54  and the outer circumference surface of the pulley  81 , the moving distance Lt of the sub-carrier  50  can be set. The total moving distance L of the sub-carrier  50  from the reference point is L=Lm+Lt, and the moving distance Lt is an offset amount of the sub-carrier  50  with respect to the carrier  15 , which is obtained from the moving distance Lm of the carrier  15 . 
     The effects of the fourth embodiment will be explained. In the fourth embodiment, the power transmission means for transmitting the driving force of the carrier  15  to the sub-carrier  50  is constituted by the rack  51  and the pinion  54 , the pulleys  81 ,  82 , and  84 , the endless belt  83  and the like, and therefore power transmission can be carried out with reliability, thus making it compact with the simple constitution. The other effects are the same as in the first embodiment, and therefore the explanation here is omitted. 
     Next, sub-carrier moving means according to a fifth embodiment will be explained based on  FIG. 16  to  FIG. 18 . The transfer press  1  used in the fifth embodiment changes the number of sets of a pair of left and right lift beams  13  and  13 , and part of the sub-carriers  50  and  50  are omitted with respect to the transfer press  1  shown in  FIG. 1  to  FIG. 4 . 
     The fifth embodiment is an example that is applied to the case in which the transfer pitch between the working stations is larger than the transfer pitches between the other working stations. Normally, the first process is deep drawing. In this deep drawing process, limitation occurs to the motion of the work transfer apparatus in order to avoid interference between the work and the die when the work is removed from the die. Consequently, in  FIG. 16 , the transfer motion from the working station W 1  that is a deep drawing process to the working station W 2  (namely, in the transfer area T 1 ) is set independently from the transfer motions in the other transfer areas T 2  to T 4 . As a result, a more ideal setting is possible for the transfer motions in the transfer area T 1  and the transfer areas T 2  to T 4 . Thus, the transfer press  1  has the constitution including a pair of left and right lift beams  13  and  13  for the transfer area T 1 , and a pair of left and right lift beams  13  and  13  for the transfer areas T 2  to T 4 . 
     The lift beams  13  and  13  for the T 1  are provided with a pair of carriers  15  and  15 , and the lift beams  13  and  13  for the T 2  to the T 4  are provided with a plurality of (three pairs in the fifth embodiment) carriers  15  and  15 . The sub-carriers  50  and  50  are provided at the lower parts of the carriers  15  and  15  for the T 2  and the T 4 , which are located at both ends of the lift beams  13  and  13  for the T 2  to the T 4  as in  FIG. 4  to make it possible to be offset. As a result, the cross bar  17  can be moved between the processes with reliability. On the other hand, the carriers  15  and  15  for the T 3 , which are located at a center of the lift beams  13  and  13  for the T 2  To the T 4 , have the constitution in which the carriers  15  and  15  directly hold the cross bar  17  without being provided with the sub-carriers  50  and  50  as shown in  FIGS. 17 and 18 , since the lift beams  13  and  13  are not divided in the transfer area T 3  for which they themselves are responsible. 
     As explained thus far, the present invention provides the following effects. 
     (1) A pair of left and right lift beams movable up and down by each lift drive means are provided for each area between the working stations in parallel along the work transfer direction, and the carrier is provided at the lift beam movably along the longitudinal direction thereof. The carrier drive means is attached to each carrier, and the carrier is provided with the sub-carrier movably along the longitudinal direction of the lift beam, and the carrier driving force by the carrier drive means is transmitted to the sub-carrier with the predetermined power transmission means to drive it. As a result, the timing of the feed motion such as the lift stroke, feed stroke, feed level and the like for each area between the working stations can be respectively adjusted, and therefore even in the case of the transfer press with different transfer pitches for a plurality of working stations, work transfer can be carried out with reliability. Accordingly, the die interference curve corresponding to a die can be set, whereby optimal die design can be made. 
     (2) The cross bar provided with the work holding means is attached to the sub-carrier, which is provided at the carrier movably in the moving direction of the carrier (the work transfer direction), whereby the cross bar can be moved to the position that is offset from the moved position of the carrier. As a result, the work transfer can be carrier out with reliability without being restricted by the length of the lift beam when the adjacent lift beams are spaced from each other and the middle position of the working station is located at the position in that space, or when the holding positions by the work holding means, that is, the moved position of the cross bar are different when the work is carried in and carried out. 
     (3) When the carrier is moved to the end portion in the longitudinal direction of the lift beam, the cross bar can be moved to the position past the end portions to the outside. Consequently, connection with the work carrying-in device or the work carrying-out device provided at the upstream side or the downstream side of the working station, for example, is facilitated, and the degree of freedom of the process design is increased. 
     (4) Since the driving force of the carrier is transmitted to the sub-carrier and drive it, the driving source for the sub-carrier is not necessary, and thus the carrier and the sub-carrier can be constructed to be compact. 
     (5) By constituting the driving source of the carrier by the linear motor, the carrier can be made light and compact, and resistance against vibration can be increased. 
     Next, the transfer press  1  will be explained based on  FIG. 19  to  FIG. 22 . In a sixth embodiment that will be described later, the transfer press  1  shown in  FIG. 19  to  FIG. 22  is used. The same components as in the transfer press  1  shown in  FIG. 1  to  FIG. 4  are given the same reference numerals and symbols, and the explanation thereof will be omitted hereinafter. In the transfer press  1 , the left side in  FIG. 19  to  FIG. 21  is assumed to be an upstream of the transfer of the work  11 , and the right side is assumed to be a downstream of the transfer thereof. 
     The transfer feeder  10  will be explained. The transfer feeder  10  successively transfers the work  11 , which is worked in each of the working stations W 1  to W 4 , in the transfer areas T 1  to T 4 , which are set along the adjacent working stations W 1  to W 4 , and is set at the downstream side of the final working station (the W 4  in this case). Accordingly, the transfer feeder  10  is constituted by four feed units  12  disposed respectively inside the transfer areas T 1  to T 4  as shown in  FIG. 20  and  FIG. 21 . 
     Each of the feed units  12  includes the following components. Namely, first of all, it includes a pair of left and right lift beams  13  and  13  movable up and down, which are placed in parallel along the work transfer direction and spaced in a horizontal direction so as not to interfere with the slide motion. At upper portions of a pair of the left and right lift beams  13  and  13 , provided are lift drive means having lift shaft servo motors  14  and  14 , and support members  14   a  which are attached to the lift beams  13  and  13  and driven up and down by the lift shaft servo motors  14  and  14 . By outputting control signals to the respective lift drive means from the corresponding T 1  to T 4  control means  3 F to  3 I, the lift beams  13  are driven to move up and down. At lower portions of the respective lift beams  13  and  13 , provided are carriers  15  and  15  to be movable in a longitudinal direction of the lift beam  13 . Between the lift beams  13  and the carriers  15 , included are carrier drive means having linear motors  16  and  16  (see  FIG. 24 ) for driving the respective carriers  15  in the longitudinal direction of the lift beam  13 . Carrier movement is controlled by outputting control signals to the respective carrier drive means from the corresponding T 1  to T 4  control means  3 F to  3 I. 
     Further, sub-carriers  30  and  30  are provided at lower parts of the respective carriers  15  and  15  to be movable in the longitudinal direction of the lift beam  13 . Linear motors  31  and  31  as sub-carrier drive means for driving the sub-carriers  30  in the moving direction of the carrier  15 , that is, in the longitudinal direction of the lift beam  13  are provided between the carriers  15  and the sub-carriers  30 . The cross bar  17  is spanned between the sub-carriers  30  and  30  provided at a pair of the left and right carriers  15  and  15  which are opposing each other. The cross bar  17  is provided with a vacuum cup device capable of sucking, for example, the work  11  at a predetermined number of spots (four spots in this embodiment) as the work holding means  18 . A control signal is inputted into the work holding means  18  of each of the cross bars  17  from the corresponding T 1  to T 4  control means  3 F to  3 I, whereby the operation of suction is controlled. 
     Next, sub-carrier drive means according to the sixth embodiment will be explained in detail based on  FIG. 23  and  FIG. 24 .  FIG. 23  is a front view of the sub-carrier drive means of the sixth embodiment, and  FIG. 24  is a right side view of  FIG. 23 . 
     As shown in  FIG. 23  and  FIG. 24 , the linear motor  16  is placed along the work transfer direction between the lift beam  13  and a frame  19  of the carrier  15 , and linear guides  27  and  27  are placed along the work transfer direction at both sides of the linear motor  16 . A guide rail  27   a  of each of the linear guides  27  is attached at a bottom surface of the lift beam  13  and a guide member  27   b  of the linear guide  27  is attached at a top surface of the aforementioned frame  19 . The guide member  27   b  is slidably engaged with the guide rail  27   a  in a state in which it is suspended from the guide rail  27   a.  Each of the linear motors  16  enables each of the carriers  15  to be self-propelled independently along the linear guides  27 . Any one of a primary coil  16   a,  and a secondary conductor (constituted by a ferromagnetic material or permanent magnet or the like)  16   b,  which constitute the linear motor  16 , is laid on the lift beam  13  side, and the other one is laid on the carrier  15  side to oppose the aforementioned one of them. The carrier  15  can be made to travel at an optional speed along the linear guides  27  by inputting a control signal into the primary coil  16   a  from each corresponding T 1  to T 4  control means  3 F to  3 I. 
     The linear motor  31  is placed along the work transfer direction between the frame  19  of the carrier  15  and a frame  32  of the sub-carrier  30 , and linear guides  37  and  37  are placed at both sides of the linear motor  31  along the work transfer direction. A guide rail  37   a  of each of the linear guides  37  is attached to a bottom surface of the frame  19  of the carrier  15  and a guide member  37   b  of the linear guide  37  is attached to a top surface of the frame  32  of the sub-carrier  30 . The guide member  37   b  is slidably engaged with the guide rail  37   a  in a state in which it is suspended at the guide rail  37   a.  The guide rail  37   a  is attached so that it protrudes outward in the carrier moving direction from the end portion in the longitudinal direction of the lift beam  13  when the carrier  15  is moved to the end portion in the longitudinal direction of the lift beam  13 . 
     Each of the linear motors  31  enables the sub-carrier  30  thereof to be self-propelled independently along the linear guide  37 . Out of a primary coil  31   a  and a secondary conductor (constituted by a ferromagnetic material, permanent magnet or the like)  31   b,  any one of them is laid on the frame  19  side of the carrier  15 , and the other one of them is laid on the frame  32  side of the sub-carrier  30  so as to oppose the aforementioned one of them. By inputting a control signal into the primary coil  31   a  from each of the corresponding T 1  to T 4  control means  3 F to  3 I, the sub-carrier  30  can be made to travel at an optional speed along the linear guide  37 . 
     Next, an operation of the sub-carrier drive means with the above-described constitution will be explained. When the carrier  15  is driven by the linear motor  16 , the carrier  15  is moved in the longitudinal direction of the lift beam  13 . When the sub-carrier  30  is driven by the linear motor  31 , the sub-carrier  30  is moved in the moving direction of the carrier  15 . As a result, the sub-carrier  30  is moved further offset with respect to the carrier  15 . Accordingly, a moving amount of the cross bar  17  is the total of adding up the moving amounts of the carrier  15  and the sub-carrier  30 , and by controlling the moving amounts of the carrier  15  and the sub-carrier  30  to be predetermined amounts, the position of the cross bar  17 , that is, the transfer position of the work  11  can be controlled. 
     Here, a transfer method of the work  11  by the transfer feeder  10  with the above constitution will be explained with reference to  FIG. 20  and  FIG. 21 . First, in the transfer area T 1 , when working in the working station W 1  is finished and the slide  5  starts to rise, the carrier  15  of the lift beam  13  at a position with predetermined height is moved toward the end portion at the side of the working station W 1  along the lift beam  13  by the linear motor  16 . In this situation, when the work transfer distance is satisfied by only the moving distance of the carrier  15 , the sub-carrier  30  is set at substantially the middle position, in the work transfer direction, of the carrier  15  and has no need to be moved. 
     However, when the work transfer distance is not satisfied by only the moving distance of the carrier  15 , namely, when the position of the working station W 1  is located at an outer side from the end portion of the lift beam  13 , the sub-carrier  30  is moved so as to be offset by predetermined distance to the working station W 1  from substantially the middle position in the work transfer direction, of the carrier  15  by the linear motor  31 . As a result, the sub-carrier  30  and the cross bar  17  are moved to above substantially the middle position of the working station W 1  (see the sub-carrier  30 A and the cross bar  17 A shown by the chain double-dashed line in  FIG. 20  and  FIG. 21 ), and the vacuum cup device (the work holding means  18 ) is moved to the work suction position of the working station W 1 . Next, the lift beam  13  is lowered at this position and the work  11  is sucked. 
     Thereafter, the lift beam  13  is raised, then the carrier  15  is moved to the downstream side, that is, the end portion of the working station W 2 , and as in the above description, the sub-carrier  30  is moved by predetermined distance in the downstream direction as the carrier  15 , as occasion demands. Then, the sub-carrier  30  and the cross bar  17  are moved to substantially the middle position (see the sub-carrier  30 B and the cross bar  17 B shown by the chain double-dashed line in  FIG. 20  and  FIG. 21 ) of the working station W 2  by being offset by the predetermined distance to the working station W 2  from substantially the middle position of the carrier  15  in the work transfer direction. Thereby, the vacuum cup device (the work holding means  18 ) is located at a work release position of the working station W 2 . Then, the lift beam  13  is lowered at this position and the work  11  is released. Subsequently, before the slide  5  of the working station W 2  is not completely lowered, namely, before press working is not started in the working station W 2 , the lift beam  13  is raised, and the carrier  15  is returned to substantially the middle position of the transfer area T 1  so that the sub-carrier  30  and the cross bar  17  do not interfere with the slide  5  and the die. 
     Subsequently, after working in the working station W 2  is finished, as the feed unit  12  in the transfer area T 1 , the cross bar  17  is also moved by the movement of the lift beam  13 , the carrier  15 , and the sub-carrier  30  in the transfer area T 2 . In the transfer areas T 3  and T 4 , the respective field units  12  are similarly driven in the same manner as above, whereby carrying-in and carrying-out of the work are performed in all the transfer areas T 1  to T 4 , and the work is finally transferred to a production carrying out device or the like not shown from the transfer area T 4 . Actually, the carrier  15  and the sub-carrier  30  are not moved in a state in which the lift beam  13  is standing still, but they are moved during up and down movement of the lift beam  13 . As a result, efficient transfer can be carried out by the simultaneous drive of the drive shaft, and the working speed (operation strokes per minute) can be increased. 
     Next, the effects according to the sixth embodiment will be explained. 
     (1) In the transfer press having a plurality of working stations, a pair of lift beams  13  and  13  corresponding to each area between the adjacent working stations are provided in parallel along the work transfer direction to be movable up and down. The respective lift beams  13  and  13  are provided with the carriers  15  and  15  which are driven along the longitudinal direction thereof by the predetermined drive means (the linear motor  16  in the sixth embodiment), and the carriers  15  and  15  are provided with the sub-carriers  30  and  30  movably in the longitudinal direction of the lift beam  13 . In addition, the sub-carriers  30  and  30  are driven by the linear motors  31  and  31 , the cross bar  17  provided with the work holding means  18  such as a vacuum cup device is spanned between a pair of the sub-carriers  30  and  30  which are opposing each other. 
     Consequently, by controlling the moving distances of the carriers  15  and  15  and the sub-carriers  30  and  30  which are corresponding to each area between the working stations, the feed stroke of the cross bar  17  can be adjusted for each area between the working stations. As a result, in the transfer press in which the transfer pitch for each area between the adjacent working stations differs, work transfer can be also carried out with reliability. Accordingly, in such a case, the length of the transfer press line can be designed to be optimally short as compared with the prior art in which all of the transfer pitches are designed to conform to the maximum transfer pitch. Even in the transfer press in which the uprights exist between the working stations, the work can be directly transferred to the next working station without providing the idle stations at the uprights, and therefore the length of the entire transfer press line including all of the working stations can be reduced. 
     (2) Since the rising and lowering stroke of the lift beam  13  and the feed stroke of the cross bar  17  can be adjusted for each of the working stations, the feed motion of the work holding means and its timing can be adjusted for each of the working stations. The origin position (feed level) of each of the working stations can be set at the position corresponding to dies. As a result, work transfer corresponding to the dies can be set for each process, and optimal die design can be made. 
     (3) Since the drive means of the carrier  15  and the sub-carrier  30  are constituted by the linear motors  16  and  31 , respectively, the constitutions of the carrier  15  and the sub-carrier  30  are made simple and compact. Consequently, the work transfer apparatus can be reduced in weight and size, and therefore the volumetric capacity of the other driving sources in the work transfer apparatus can be reduced, thus reducing production cost. By reducing the weight of the work transfer apparatus, chatter of the bars at the time of actuation and stoppage and at the time of inching can be controlled, and durability of each part of the work device can be improved. Further, since increase of speed and accuracy of position can be achieved by the linear motors, even when there is an area having a longer transfer pitch than the other areas between a plurality of working stations, slaved following can be sufficiently performed, thus making it possible to correspond to a high-speed operation of the press. 
     (4) In the sixth embodiment, each of the carriers  15  is provided with the sub-carrier  30  at which the cross bar  17  is spanned, but this is not restrictive. For example, according to the necessity of the degree of freedom of the design of a die, necessity of a large feed stroke, and the like, a desired position is determined out of a plurality of carriers  15  and only the corresponding carrier  15  may be provided with the sub-carrier  30 . In this case, the work transfer distance can be optionally set by the feed stroke of only the carrier  15 , and adding up the strokes of the carrier  15  and the sub-carrier  30 . Explaining with regard to use, there is a case in which a transfer pitch between the working stations is larger than the transfer pitches between the other working stations. For example, in the working station (W 1 ) at the uppermost stream side of the transfer press, a blank material is worked, thus the size of the die is larger as compared with the size of the dies of the following processes, and the transfer pitch between the working station (W 1 ) and the working station (W 2 ) is larger than the transfer pitches between the working stations of the following processes. 
     In this case, a pair of carriers  15 , which are opposing each other and include the sub-carriers  30  between which the cross bar  17  is spanned, are provided in the transfer area between the working stations with the larger transfer pitch. As a result, a larger feed stroke can be set than the transfer areas between the other working stations which are provided with the carriers  15  (see  FIG. 30  and  FIG. 31 ) between which the cross bar  17  is directly spanned laterally, and therefore an optimal die design is possible. As described above, only the lift beams  13  corresponding to the required working station are provided with a pair of the carriers  15 , which are opposing each other and includes the sub-carriers  30  between which the cross bar  17  is laterally spanned, whereby the cost can be reduced to the minimum required amount. 
     (5) It is constituted that when the carrier  15  is moved to the end portion in the longitudinal direction of the lift beam  13 , the guide rail  37   a  of the linear guide  37 , for guiding the sub-carrier  30  provided at the carrier  15 , exceeds the end portion in the longitudinal direction of the lift beam  13  outward in the carrier moving direction. As a result, the cross bar  17  can be moved to the position past the end portion of the lift beam  13  outward. Consequently, even when a plurality of lift beams  13  are disposed substantially in line in the work transfer direction and the adjoining portions of the adjacent lift beams  13  are at substantially the center of the working station, work can be transferred to the die position at substantially the center of the working station with reliability, and there is no limitation in the transfer pattern. Further, for example, when the material supply device, the product carrying-out device (both are not illustrated), or the like is placed at the upstream or the downstream side of the working station, work transfer can be performed correspondingly to various kinds of material supply devices and the product transfer devices without being restricted by the length in the transfer direction of the lift beam  13 , and therefore the degree of freedom of the process design of the transfer press line is increased. 
     In the sixth embodiment, an example using the linear motor  16  as the carrier drive means is shown, but this is not restrictive. For example, as shown in  FIG. 25 , a pinion  42  rotationally driven by a servo motor  43  and a rack  41  attached in the longitudinal direction of the lift beam  13  may be meshed with each other, and thereby the carrier  15  may be driven by the servo motor  43 . Alternatively, a power transmission mechanism such as a ball screw may be used. In the sixth embodiment, the lift beam  13  is independent for each process, but the lift beam  13  may be independent for a plurality of processes. In this case, a plurality of carriers are provided on one lift beam  13  to perform work transfer between the respective working stations. 
     In a work transfer apparatus, in which a long lift beam extending along all the working stations is provided, carriers are connected to each other, and each of the carriers makes the same motion and the same stroke with one feed drive means as in the prior art, the feed stroke of the cross bar can be adjusted for each working station by providing sub-carriers at the carriers. By further driving the sub-carriers with the linear motor, an increase in the weight of the work transfer apparatus can be controlled to a minimum. 
     The lift beams  13  in the sixth embodiment are provided in parallel with the work transfer direction and in pairs in the lateral direction. However, as shown in  FIG. 26 ,  FIG. 27  and  FIG. 28  according to a seventh embodiment, they may be placed at substantially the center in the lateral direction without being paired. In this case, the lift beam  13  is placed so as not to be in the press working area between the slide  5  and the bolster  6 A, and the cross bar  17  is moved at the moving stroke of the sub-carrier  30  to substantially the center of the working station from the end of the lift beam  13 .  FIG. 26 ,  FIG. 27  and  FIG. 28  shows the case of a tandem press line constituted by presses  2 A,  2 B,  2 C and  2 D, arid this work transfer apparatus may be used in a transfer press. 
     It is not necessary that the drive means of the sub-carrier is a linear motor as to the construction in which the guide for guiding the aforementioned sub-carrier is protruded in the moving direction of the carrier from the end portion of the lift beam when the carrier is moved to the end portion of the lift beam. Namely, the drive means may be other drive means, and the constitution, in which the sub-carrier does not have its own drive source and moves following the movement of the carrier, may be adopted.  FIG. 29  shows an embodiment in which the sub-carrier moves following the movement of the carrier. 
     In  FIG. 29 , a pinion shaft is rotatably provided at substantially the center portion on the side surface of the carrier  15 , and the pinion  54  is attached at the end portion of the outer side of the pinion shaft. The pinion  54  is meshed with the rack  51  provided at the side surface of the lift beam  13 . The pulley  81  is attached at the other end portion of the pinion shaft. The pulleys  82  and  82  are rotatably provided at both end portions in front and at the rear of the carrier  15  in the longitudinal direction of the lift beam  13  (namely, the work transfer direction), and the endless belt  83  such as a timing belt is wound around the pulley  81  and the pulleys  82  and  82 . The sub-carrier  30  is attached to the endless belt  83  between the front and the rear pulleys  82  and  82 , and predetermined tension is given to the endless belt  83  with the tension pulleys  84  and  84  provided in the vicinity of the areas in front and behind the pulley  81 . According to this constitution, the sub-carrier  30  moves following the movement of the carrier  15  and moves along the longitudinal direction of the lift beam  13 . 
     As explained in the above-described sixth and seventh embodiments and the like, the present invention provides the following effects. 
     (1) The lift beam movable up and down by the lift drive means is provided in parallel along the work transfer direction, the carrier is provided at the lift beam movably along the longitudinal direction thereof, and the sub-carrier is provided at the carrier movably along the longitudinal direction of the lift beam by the linear motor. Consequently, timing of the feed motions such as a lift stroke for each of the lift beams or each pair of the lift beams, feed stroke, and feed level can be adjusted respectively, work transfer can be performed with reliability even in the case of a transfer press with different transfer pitches between the working stations. Accordingly, work transfer corresponding to a metal die can be set, whereby optimal die design can be made. 
     (2) The sub-carrier is attached to the carrier movably in the carrier moving direction (work transfer direction), and the work holding means or the cross bar provided with the work holding means is attached to the sub-carriers. As a result, the work holding means can be moved to the position which is offset outward in the carrier moving direction from the middle position of the carrier. Consequently, when the adjacent lift beams are spaced, and the center position of the working station is located at the spaced position, or when the holding position by the work holding means or the moved position of the cross bar differs at the time of carrying in and carrying out the work in the same working station (die), the work transfer can be performed with reliability without being restricted by the length of the lift beam. 
     (3) By constituting the driving source of the sub-carrier by the linear motor, the constitution of the carrier and the sub-carrier is made simple and compact, and the work transfer apparatus can be reduced in weight and size, thus making it possible to reduce the volumetric capacity of the other driving sources in the work transfer apparatus and reduce the production cost. By reducing the work transfer apparatus in weight, chatter of the bars at the time of actuation and stoppage and at the time of inching can be reduced, and the durability of each component of the work apparatus can be increased. Further, since increase of speed and accuracy of the position can be enhanced by the linear motor, even when there is a spot with a longer transfer pitch than the other spots between a plurality of working stations, slaved tacking can be sufficiently performed, which makes it possible to correspond to a high speed operation of the press. 
     (4) A pair of carriers opposing each other, which are provided with the sub-carriers between which the cross bar is laterally spanned, are provided at only the lift beams corresponding to the transfer area requiring a larger feed stroke than the transfer areas between the other working stations, whereby the cost can be reduced as necessary. 
     (5) Since the cross bar can be moved to the position past the end portion outward when the carrier is moved to the end portion in the longitudinal direction of the lift beam, for example, connection to the material supply device or the production carrying-out device provided at the upstream side or the downstream side of the working station is facilitated, and the degree of freedom of the process design is increased.