LOCKING DEVICE OF TRANSFER FEEDER

Abstract: A locking device of a transfer feeder for preventing unexpected movement of a transfer bar or a driving part therefor and capable of locking the transfer bar at any desired position exactly. The locking device includes: a feed carrier (5a); a plurality of catching plates (8) each fixed to an equalizer bar (6) provided for a lift/clamp mechanism and having a plurality of catching holes (8a) drilled at intervals lengthwise; and a plurality of locking pins (13) fixed to a press itself at several points so as to oppose the catching plates (8) and movable right and left as well as back and forth by driving units (11, 15) so that each pin can engage with any one of the catching holes.

Description: The present invention relates to a locking device for transfer feeder employed in a transfer press where the features of the preamble part of claim 1. A transfer feeder with such a locking device is known from JP-A-57-49029. The known transfer feeder is employed in a conventional transfer press and comprises at least one transfer bar which is movable in two-dimensional or three-dimensional directions. The transfer bar is adapted to be driven by a driving force taken-off by a power take-off of the transfer press. In the above-mentioned conventional transfer feeder, when maintenance or repairing of the driving section in the feeder, an engineer enters within the feeder to perform maintenance or repair by stopping motion of the feeder. A hydraulically actuated pin is lifted and comes into abutment with a protrusion provided on a part connected to the transfer bar. However, it is not possible to lock the transfer bar in a selected position. Therefore, it is an object of the present invention to provide a locking device for a transfer feeder which can certainly lock transfer bars at desired positions so that the transfer bars and the driving positions will never initiate motion unexpectedly. This object is solved by characterising features of claim 1. Advantageous embodiments of the invention are disclosed by the features of the subclaims. With the present invention having the above-mentioned respective features, since the locking device for mechanically locking the drive mechanisms for driving the transfer bars in feeding, lifting and clamping directions, even when engineer performs maintenance or repair by entering into the transfer feeder, the transfer bars or its driving portions will never move unexpectedly due to their own weight or so forth to ensure safety in maintenance and repairing operations. In addition, since it is constructed that the locking pin detecting the engaging hole in the engaging plate enters into the detected engaging hole, lock can be certainly established even when the transfer bars are stored at any desired position. The above-mentioned and other objects, aspects and advantages of the present invention will become clear to those skilled in the art from the discussion described and illustrated in connection with the accompanying drawings which illustrate preferred embodiments meeting with the principle of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of in the vicinity of a feed driving mechanism, in which the preferred embodiment of the present invention is employed; Fig. 2 is an enlarged perspective view of the preferred embodiment of the present invention; Fig. 3 is schematic illustration showing overall construction of a lock system of a transfer feeder employing another embodiment of the present invention; Fig. 4 is a schematic plan view of a lock cylinder employed in the embodiments of the invention and elements in the vicinity thereof; and Fig. 5 is a section of the lock cylinder to be employed in the embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be discussed herebelow in connection with the accompanied drawings. At first, discussion will be given for the first embodiment of the present invention with reference to Figs. 1 and 2 . In Fig. 1 , the reference numeral 1 denotes a main body of a transfer press, which includes a moving bolster 2 . A pair of transfer bars 4 of a transfer feeder 3 are provided above the moving bolster 2 . The transfer bars 4 are provided in parallel relationship orienting in parallel to the transfer direction of not shown works. The transfer bars 4 are adapted to be driven in three-dimensional directions of feeding direction, lifting direction and clamping direction by a driving force taken off by a not shown power take off provided in the main body of the press 1 . A locking device 7 according to the present invention, is provided in the vicinity of a feed carrier 5a of a feed drive mechanism 5 or an equalizer bar 6 provided in a lift and clamp mechanisms (both being not shown). As shown in Fig. 2 , the locking device 7 has an engaging plate 8 fixedly secured on the feed carrier 5a or the equalizer bar 6 . The engaging plate 8 is formed with a plurality of engaging holes 8a aligned in the longitudinal direction with a regular interval and dogs 8b at the positions corresponding to the engaging holes 8a . The dogs 8b are adapted to be detected by means of a detector 9 , such as a proximity switch, movable along the engaging plate 8 . The detector 9 is mounted on a sliding member 7b movably supported on a base 7a of the locking device 7 via a bracket 10 . A thread shaft 12 which is rotatingly driven by a feeding motor 11 is engaged with the lower portion of the sliding member 7b so that the sliding member 7b is driven to move along the engaging plate 8 by means of the feeding motor 11 . The sliding member 7b carries a locking pin 13 in opposition to the engaging plate 8 , which lock pin 13 has a tip end entering into the engaging hole 8a of the engaging plate 8 to lock the engaging plate 8 . The locking pin 13 is normally biased toward the engaging plate 8 by means of a compression spring 14 so as to establish locking for the engaging plate by the effect of the compression spring 14 . The rear end of the locking pin 13 is connected to a hydraulic cylinder 15 so as to unlock the engaging plate in response to a hydraulic pressure supplied from a pressurized fluid source 18 via an electromagnetic valve 16 and a piping 17 . It should be noted that, in the drawings, the reference numeral 19 denotes a detector for detecting locking and unlocking states of the locking pin 13 . Next, discussion will be given for operation. Upon maintenance or repair of the transfer feeder 3 , once the transfer feeder 3 is stopped, the sliding member 7b is driven by revolution of the feeding motor 11 to move along the engaging plate 8 . Since the detector 9 is provided on the sliding member 7b , the detector 9 detects the dogs 8b of the engaging plate 8 . In response to a signal from the detector 9 , an electromagnetic valve 16 is switched from a communicating position 16a to a drain position 16b so that a work fluid in the hydraulic cylinder is drained. By this, the locking pin 13 is projected in the direction toward the engaging plate 8 by the action of the compression spring 14 and thus inserted into the engaging hole 8a at the corresponding position to the detected dog 8b . Therefore, the feed carrier 5a or the equalizer bar 6 of the lifting and clamping mechanisms fixed to the engaging plate 8 can be mechanically locked. Therefore, unexpected movement of the transfer bars due to its own weight during maintenance or repairing operation can be certainly prevented. Next, the second embodiment of the present invention will be discussed in connection with Figs. 3 to 5 . As can be clear from Fig. 3 , by a power take off 25 mounted thereon, a press main body 21 takes off the driving force for rotatingly driving a cam shaft 26 by the taken off driving force. A feeding cam 26a , a clamping cam 26b and a lifting cam 26c are provided on the cam shaft 26 . A feed carrier 27 is driven by the feeding cam 26a . A clamping drive lever 28 is driven by the clamping cam 26b . A lifting drive lever 29 is driven by the lifting cam 26c . The transfer bars 24 are driven in a three-dimensional directions, i.e. feeding and returning direction, clamping and unclamping direction and lifting and lowering direction, by the feed carrier 27 , the clamping drive lever 28 and the lifting drive lever 29 . Locking devices 30 1 , 30 2 and 30 3 , according to the present invention, are respectively provided in the vicinity of the feed carrier 27 , the clamping drive lever 28 and the lifting drive lever 29 . The locking device 30 1 provided for the feed carrier 27 has locking cylinders 31 arranged at both sides of the feed carrier 27 . A piston rod 31a projected from the locking cylinder 31 is adapted to insert the tip end portion thereof into an engaging hole 32a of an engaging plate 32 provided on the upright side 21a of the press main body 21 for locking the feed carrier. On the other hand, as shown in Figs. 4 and 5 , the locking devices 30 2 and 30 3 provided in the vicinity of the clamping drive lever 28 and the lifting drive lever 29 have locking cylinders 31 which are constructed to engage the tip ends of the piston rods 31b to a plurality of recess form engaging portions 28a and 29a respectively aligned in the longitudinal directions of the clamping drive lever 28 and the lifting drive lever 29 . The locking cylinders 31 are mounted on a stationary portion, such as a bed of the press main body 21 by means of brackets 30a . As shown in Figs. 3 to 5 , the interior space of the lock cylinder 31 is divided into a pressure chamber 31 1 and a spring chamber 31 2 by the piston 31a . A hydraulic pressure is supplied to the pressure chamber 31 1 from a pressurized fluid source 33 via an electromagnetic valve 34 . On the other hand, a compression spring 31d for biasing the piston 31a in the locking direction is housed within the spring chamber 31 2 . An actuation rod 31c provided on the piston 31a to project toward the spring chamber 31 2 externally extends from the cylinder 31 . A dog 35 is carried on the tip end of the actuation rod. A lock detector 36 comprising a proximity switch is adapted to detect the dog 35 . Next, operation of the foregoing embodiment will be discussed. Upon maintenance or repair of the transfer feeder 23 , once the transfer feeder 23 is stopped, the hydraulic pressure supplied to respective of the pressure chambers 31 1 of the locking cylinders 31 are drained by switching respective electromagnetic valves 34 from communicating positions 34a to drain positions 34b . By this, the piston rods 31b maintained at the retracted position by the hydraulic pressure project toward the engaging plate 32 , the clamping drive lever 28 and the lifting drive lever 29 . As a result, tip ends of respective piston rods 31b enters into the engaging portions 32a , 28a and 29a to lock the feed carrier 27 , the clamping drive lever 28 and the lifting drive lever 29 . Since the motion of the transfer bars 24 in the feeding and returning direction, the clamping and unclamping direction and lifting and lowering direction is restricted, unexpected motion of the transfer bars 24 due to their own weight can be certainly prevented.

Claims: A locking device (7, 30) for a transfer feeder (3) of a transfer press, which transfer feeder includes a pair of transfer bars (4, 24) driven in two or three dimensional directions, comprising engaging means, locking means, and driving means for driving said locking means in engagement with said engaging means, characterized in that the engaging means (8, 28, 29, 32) are fixedly mounted on one of a drive mechanism (6, 28, 29) of said transfer bar (4, 24) and a stationary portion of a press main body (1, 21); the locking means (13, 31) are fixedly mounted on the other said drive mechanism and said stationary portion of said press main body (1, 21) for engaging with said engaging means, said locking means cooperate with said engaging means for selectively establishing locking engagement at a plurality of preselected relative positions between said drive mechanism and said stationary portion of said press main body; and the driving means (14, 15, 16, 17, 18, 31d, 33, 34, 34 1 , 2,3 ) establish locking at a selected relative position of said drive mechanism and said stationary portion of said press main body (1, 21). Locking device according to claim 1, characterized in that said engaging means (8, 28, 29, 32) comprises a plurality of engaging plates (8) fixed on a feed carrier and equaliser bar (6) provided in lift/clamping mechanism which forms said drive mechanism and having a plurality of engaging holes (8a) formed in alignment in the longitudinal direction with a regular interval, and said locking means (13) comprises a plurality of locking pins (13) provided at a plurality of stationary portions of said press main body (1) respectively in opposition to said engaging plates (8) and movable in axial and lateral directions by means of said driving means (11) to engage with one of a plurality of said engaging holes (8a). Locking device according to claim 2, characterized in that each of said engaging plates (8) has dogs (8b) at predetermined positions corresponding to each engaging hole (8a) and engagement and release of said locking pin (13) relative to said engaging holes is controlled by detecting one of said dogs by means of a detector (9). Locking device according to claim 1, characterized in that said engaging means (8, 28, 29, 32) comprises an engaging plate (32) secured on the stationary portion of the press main body (21) and having a plurality of engaging holes (32a) formed in alignment in a feed direction of a feed carrier (27) with a given interval, an engaging portion having a plurality of recessed grooves (28a) formed in a clamping drive lever (28) in alignment in the longitudinal direction thereof with a given interval and an engaging portion having a plurality of recessed grooves (29a) formed in a lifting drive lever (29) in alignment in the longitudinal direction thereof with a regular interval, and said locking means (31) comprises a plurality of locking cylinders (31) secured on said feed carrier (27) and two portions of the press main body (21) respectively in opposition to said engaging plate and two engaging portions to engage with respective one of engaging holes (32a) and recessed groove (28a, 29a). Locking device according to claims 2 or 4, characterized in that said locking means (13, 31) is placed at a locking position by biasing means (14, 31d) and at an unlocking position by a hydraulic pressure (18, 33).

Inventors: HIROTA YUJI OBISHI-MACHI, KAJI NOBUYUKI, TANAKA TOSHIHIRO, HIROTA, YUJI, KAJI, NOBUYUKI, TANAKA, TOSHIHIRO, HIROTA, YUJI 48, OBISHI-MACHI, KAJI, NOBUYUKI 3-72, NISHIKARUMI-MACHI, TANAKA, TOSHIHIRO 118, SHIMA-MACHI O
Applicants: KOMATSU MFG CO LTD, KABUSHIKI KAISHA KOMATSU SEISAKUSHO
Application year: 1990
Main classification: B21D43
IPC codes: B21D43