Patent GB-526307-A (GB)
Title: Improvements relating to sheet-metal-working presses and the like
IPC: F16P3/00
Filed: 1939-03-13
Abstract: 526,307. Metal-working presses. GLASNER, R. W. March 13, 1939, No. 7991. [Class 83 (iv)] [Also in Group XXIV] A sheet metal working press or the like having a heavy presshead reciprocated by a power drive through a clutch has a locking device for the head connected to the clutch for operation by means responsive only to the opening movement of the clutch so that whenever the clutch is opened the lock is automatically engaged to lock the head positively against movement. The press comprises a bed 15, Fig. 3 above which a slide 26 is adapted to be reciprocated through gearing 32, 33 and 35, eccentrics 27 and straps 29 from a, shaft 36 to one end 62 of which shaft a pulley 57, Fig. 6, driven by a belt from a motor 60 may be coupled through a clutch. The pulley is loosely mounted on the shaft and adjoins a hub 67 keyed to the shaft and carrying an integral clutch member 63 and a splined clutch member 66. Between the members 63 and 66 is an annular friction member 72 having peripheral teeth 71 engaging teeth 70 on a ring secured to the pulley. A cylinder 73 keyed to the shaft has a piston 75 secured to the clutch member 66. A hub 94 also keyed to the shaft carries an integral brake element 93 and a splined brake element 85 and between the two is an annular friction member 100 engaging a ring 96 secured to the framework of the machine. A series of pins 90 extend from the piston 75 and each is surrounded by a spring 91 bearing against a member 87 secured to the brake member 85, the arrangement being such that the springs tend to separate the clutch elements and engage the brake elements. By supplying fluid to the cylinder 73, the clutch is engaged, the brake released and the slide 26 operated. When the slide is inoperative it is locked by means of spring operated toothed pawls 24, Fig. 3, engaging in the teeth of racks 23 mounted on the machine frame. The pawls may be released by means of pistons operating in cylinders 47 which can be supplied with fluid by way of pipes 143 and 53 from a reservoir 139. When the pawls are released, rods 41 effect the closing of electric switches 149. The supply of fluid from the reservoir 139 to the clutch cylinder 73 is by way of a pipe 115 and an electrically operated valve, Fig. 8, comprising a casing 103 with a chamber 104. Within the chamber is a hollow composite member 109 slidably mounted on a tubular member 105 having lateral openings 107 and 108 on opposite sides of a transverse partition. The member 109 is held in a recess in a rod 129 depending from a lever 124 and is normally held in its uppermost position by a spring 131 but may be moved downwardly by means of a solenoid 122 which acts on an armature 123 connected to one end of the lever. In the lower position of the member 109 fluid passes from the reservoir 139 through pipe 115, passage 117, openings 108, the member 109, openings 107 and pipes 119, 120, 101 and 102 to the cylinder 73. The supply of fluid from the main supply pipe to the reservoir 139 is controlled by a similar valve 140, operated by a solenoid 141. In operation, switches 154, 155 and 156 are closed to operate the motor 60 and energize solenoid 141 to supply fluid to the reservoirs 139, whence it flows to the cylinders 47 to release the locking pawls 24 and close the switches 149. The closing of a switch 151 by the operator then energizes the solenoid 122 to supply fluid to the cylinder 73 and effect the engaging of the clutch and the release of the brake. The slide 26 is then reciprocated. On shutting off the motor, the fluid escapes from the cylinders thus disengaging the clutch, putting on the brake and engaging the locking pawls 24. By means of switches 161 and 162, the solenoids 141 and 122 may be energized for permitting an advancing movement or inching of the slide 26 while the motor is inoperative, the switch button 162 being held depressed and the button 161 being intermittently depressed. The construction of the clutch and brake is more fully shown and described in Specification 498,925, [Group XXIV].