Patent GB-1315152-A (GB)
Title: Punch holders and drive-transmission assemblies
IPC: B21D37/14
Filed: 1970-04-02
Abstract: 1315152 Punching HOUDAILLE INDUSTRIES Inc 2 April 1970 15691/70 Heading B3W A punch-holder and drive-transmission assembly 14, Fig. 1, for slidable mounting in an upper tool holder 15 has a socket 53 to receive the shank 65 of a punch, balls 62 movable, in passageways 61 itersecting the socket, between a normal punch-retaining position in which they engage in an annular groove 67 in the shank and a punch-release position and means such as a clamp 64 for holding the balls 62 in their punchretaining position and selectively allowing them to be moved to the punch-release position by relative movement between the punch shank and the socket. The upper part of the socket 53 comprises a wall 60, projecting upwardly from the punch-holder portion 42, in which the passageways 61 are formed. A snap ring 63 surrounds the wall, urging the balls 62 inwards. The clamp 64 is held in its Fig. 1 position by a spring-loaded plunger (85) (Fig. 2, not shown) engageable in a groove 91 in the stem of the clamp. When the clamp 64 has been withdrawn to its punch-release position a pin may be inserted through passage 96, Fig. 1, or passages (95), Fig. 2, to tap the punch 60 and move the balls 62 outwardly. A stripper sleeve 28 carrying a stripper plate 31 is retained in the tool holder 15 by a ring 29 and relative rotation between the sleeve 28 and the holder is prevented by engagement of a pin 59 on the sleeve 28 within a groove 23 in a sleeve 18. Relative rotation between the assembly 14 and the sleeve 28 is prevented by engagement of a pin 56 on the punch holder portion 42 in a groove 37 in the sleeve 28. A pin 75 on punch head 68 engages in a groove 55 in the punch holder portion 42 to prevent relative rotation between the punch and the holder. When punch heads of significantly smaller diameter than the internal diameter of the stripper sleeve 28 are used, one or more horizontal annular stripper plates (31a) Fig. 3, or (31b), (102), Fig. 4 (neither shown) are used. In an alternative embodiment, Fig. 5, the stripper sleeve 28a is urged away from a ring 106 by a lost-motion connection 107 comprising stripping springs 109 surrounding bolts 108 and the ring 106 is urged away from the tool holder portion 16b by lifter springs 112. The clamp 64 is held in its punch-retaining position by a spring-loaded plunger 85a movable outwardly by means of a pin 123 to release the punchretaining balls 62a. Each punch-holder and drive-transmission assembly 14b of the upper turret of a turret press has a T-section groove 137 to receive the press ram (not shown) in one turret position and a loading/unloading ram 138 in another, Fig. 6. The clamp 64b is held in punch-retaining position by a spring-loaded pin 177 which can only be moved outwardly to allow the clamp to be withdrawn when it is aligned with a groove 183 in the turret sleeve 132. The assembly 14b is supported while it is rotated between the loading/unloading station and the punching station by a spring-loaded detent 139 which yields when either ram applies force to the assembly 14b. The detent 139 may be replaced by a pivoted dog (310), Fig. 13 (not shown), spring-loaded to a position in which one end projects into the ram recess (137e) and the other wedges against a turret member (135a) to support the assembly (14e). A stripper sleeve 148, punch 147, die 149 and spacer plate 151 form a nestable tool unit 146. The stripper sleeve 148 carries a stripper plate 157 and stripper pins 173 force the stripper plate against a workpiece during punching. With the assembly in loading position a tool unit 146 is loaded from below, the punch shank 167 first pushing the balls 62b outwardly and then allowing the snap ring 63b to move them into the punch groove 67b. The assembly is then raised, the pin 177 being cammed inwardly by engagement of cam face 185 with the edge of groove 183. In a further embodiment, Fig. 7, not shown, the pin 177 is replaced by spring-loaded pins (199) which have ball followers (205) at their outer ends which are engageable in grooves (183a) for loading/unloading. Fig. 11 shows a still further embodiment of a turret press in which the balls 62d are held in their punch-retaining position by a sleeve 255 which has a lost-motion connection with a body portion 252 of the assembly 14d. Pins 263 engaging spring-loaded pistons 268 in the ram 259 are screwed to the sleeve 255 which at its lower end engages a stripper sleeve 282. A tool unit is loaded into the assembly 14d, with the body portion 252 in its lowest position relative to the sleeve 255, by passing it through the die aperture and the socket 274 of the assembly, the punch shank camming the balls 62d outwardly into recesses 279, in the sleeve 255, containing resilient plugs 280. As the shank is raised further, the balls are ejected into the groove 299 and a loading/unloading ram (not shown) lifts the assembly 14d, the body portion 252 rising relative to the sleeve 255 to the Fig. 11 position. To unload a tool unit, the ram drives the assembly 14d down until a flange 265 on the sleeve engages a cushion 242. The portion 252 then moves downwards alone until the ball passageways 61d are aligned with the recesses 279. An ejection pin passing through the ram forces the punch shank past the balls 62d.