Patent GB-1086046-A (GB)
Title: Improvements in automatic presses
IPC: B21D28/08
Filed: 1965-09-06
Abstract: 1,086,046. Quincunx feeds. OFFICINE CEVOLANI S.p.A. Sept. 6, 1965 [June 7, 1965], No. 37952/65. Heading B3W. In a press for cutting out circular or rectangular pieces from a sheet which has been previously lithographed with a regular design the sheet is fed longitudinally and transversely under a reciprocating punch and the feed steps are controlled in size and direction by a series of micro-switches actuated by adjustable stops 251 on a drum 44 driven from the crank-shaft of the press. General construction of press.-A motor 20 drives a pulley 21 which is connected through a friction clutch to the crank-shaft 23. The cross-head 39 carries a blanking punch 38 and a second punch 36 which divides the scrap webbing. The co-operating dies are carried by a bolster 37. The work to be punched is supported by and slides on a plane table 119, Fig. 8, which is supported by two frame members 115, 148. A longitudinal feed carriage comprising two side plates 109, 147 connected by members 111, 112 and 150 runs on rollers 114 which bear on the frame members 115, 148. The lower edges of the frame members have rack teeth which are engaged by two pinions 116 mounted on a shaft 118 supported in the side plates 109, 147. Sliding on the members 111 and 112 is a transverse feed carriage 133 which carries a beam 120. Adjustably mounted on the beam are two gauging stops 131, 134 which co-operate with reference marks printed on the sheet and a pair of grippers 123, 135 which engage the trailing edge of the sheet. The sheet is initially positioned transversely by an adjustable stop 163 which is mounted on a shaft 164, which also carries a pinion 166. A rack 168 which engages the pinion can be reciprocated by a pneumatic cylinder 174 to oscillate the stop 163 between a non-operative position shown in solid lines and an operative position shown in dotted lines. Driving mechanism for the transverse feed carriage.-Mounted on the crank-shaft 23 is an adjustable throw crank-pin 24 connected by a rod 26 to a bell crank 32. The bell crank pivots on a shaft 47 to which is connected a uni-directional clutch mechanism so that the shaft 47 rotates only in a clockwise direction Freely mounted on the shaft 47 are a pair of bevel gears 63, 68 which both mesh with a third bevel wheel 61. Either of the bevel gears 63, 68 can be locked to the shaft 47 by a dogclutch, controlled by the solenoids 65 and 66. The third bevel gear 61 is mounted on a shaft 60 which also has freely mounted thereon a pair of gear-wheels 51, 59. Either of the gearwheels can be locked to the shaft 60 by a second dog clutch 50 which is controlled by a solenoid 53. The gear-wheel 59 meshes with a similar size gear-wheel 48 and the gear-wheel 51 meshes with a gear 49 which has twice as many teeth as the gear-wheel 51. The gears 48 and 49 are both fixed on a shaft 99. Splined to the shaft 99 is a chain sprocket wheel 98. A chain 97 passes over the sprocket 98 and a similar sprocket 73 at the far side of the machine and is attached to the transverse feed carriage 133. Also mounted on the shaft 99 is a bevel gear 46. which meshes with a bevel gear 45 to which is secured the drum 44. When the solenoid 65 is energized the transverse feed carriage is displaced towards the shaft 99 at each stroke of the press, and when the solenoid 66 is energized the carriage moves away from the shaft 99. In order to obtain a feed step of precisely the required amount a spacing rack 75 is provided and is engaged by a detent 74. This detent is reciprocable in a vertical guide and is actuated through a toggle joint 76, 77 and a shaft 87 by a spring contained in a pneumatic cylinder 103. The detent is withdrawn from the rack by admitting pressure air to the cylinder 103. Driving mechanism for the longitudinal feed carriage.-Connected to the bell crank 32, which is oscillated by the connecting rod 26, is a tie rod 105 which reciprocates a slide 107 mounted on a guide bar 106. Attached to one side of the guide bar 106 is a sawtooth rack 108 which is engaged by correspondingly shaped teeth on a bell crank lever pivoted to the slide 107. The lever is normally disengaged from the rack by a spring 82 but can be brought into engagement by energizing a solenoid 83. The size of the longitudinal feed step is adjusted by sliding the pin 104 along a slot in the arm of the bell crank 32. The precise amount of the longitudinal feed step is also controlled by spacing racks, 70 and 84 which are engaged by spring-loaded detents 71 and 85. These detents are displaceable in vertical guides and are retracted by levers 72 and 86 mounted on a shaft 88 which is supported in the side plates 109, 147. A lever 90 is mounted at one end of the shaft 88 and is connected by two tie rods 95, 101 to a rocker lever 96. There are slots in the lower ends of the tie-rods to provide a lost-motion connection to the rocker-lever. Operating cycle.-At the beginning of a complete cycle of operations for cutting the blanks from a sheet depicted in Fig. 2 (not shown) in which the centres of the blanks in adjacent rows are displaced by half the pitch of the blanks, the motor 20 is running, the clutch is disengaged and a brake is applied to the crank-shaft 23. The sheet is placed on the work - table and is positioned by the stops 131, 134 and 163. The edge of the sheet is between the open jaws of the grippers 123 and 135. The cycle is then started by depression of a pedal which causes the energization of an electromagnet (204), Fig. 6 (not shown). This rotates an arm (202) which in turn rotates a lever (199). The end of the lever is withdrawn from engagement with the end of a curved arm 140 which is rotated by a spring (191) so that a projection (193) on the lever engages an arm 122 secured to the shaft 121 and closes the grippers on to the sheet. The punch then cuts the first blank and during the upward movement of the punch the bell crank 32 rotates the shaft 47 clockwise. A micro-switch 5, Fig. 9 (not shown) actuated by the drum 44 has already energized the electromagnet 65 so that the transverse feed carriage is displaced towards the shaft 99. Simultaneously a cam (not shown) on the bell crank 32 operates a valve which admits air to the cylinder 103 to disengage the detent 74 momentarily. These steps are repeated until the first row of blanks has been cut, when a micro-switch 4 is actuated which de-energizes the electromagnet 65 and energizes the electromagnet 66 thus causing reversal of the direction of transverse feed. At the same time a micro-switch 6 is actuated which energizes the electromagnet 55. This operates the dog clutch 50 to connect the shafts 60 and 99 by the gear-wheels 51 and 49 so that the rotation of the shaft 99 and hence the amount of the transverse feed step is reduced to one-half of the normal amount. The micro-switch 6 also energizes the electromagnet 83 so that the longitudinal feed carriage is displaced. Finally the micro-switch 8 is actuated which de-energizes the electromagnets 83 and 53 thus re-establishing the normal transmission ratio between the shafts 60 and 99. A similar succession of events occurs at the end of each line, the webbing resulting from the punching operation being continually divided by the scrap cutter 36. When the sheet is brought into position to cut the last row of blanks a roller 117 on the shaft 118, engages an arm (215), Fig. 11 (not shown), and rotates a shaft (213) which raises the actuator (218) of a pneumatic valve (209) and a micro-switch (2), into alignment with a cam (208) mounted on the drum 44. Consequently when the sheet is brought into position to cut the last blank and the punch is on its return stroke the cam (208) actuates the micro-switch (2) which disengages the clutch 22. Operation of the valve (209) permits admission of air to a pneumatic cylinder 30 connected to the guide bar 106 which returns the longitudinal feed carriage to the starting position. As this withdrawal occurs a lever 197, Fig. 6 (not shown) which on the last longitudinal feed step passed freely under the lower end of the lever 140 rotates this lever and opens the grippers 123 and 135. The remnant of the sheet is then removed from the machine by an ejector 162 which is mounted on a pivoted arm 154. The arm is rotated by a pneumatic cylinder 160 controlled by the valve 209. The power for returning the transverse feed carriage to its starting position is derived from the return movement of the longitudinal feed carriage by means of a bevel gear 144 mounted on the shaft 118 which is rotated by the pinions 116 which mesh with the teeth on the frame members 115, 148. The bevel gear 144 meshes with two bevel gears 142 and 145 both of which rotate freely on a shaft 146. By means of a doublesided dog-clutch either of the bevel gears 142, 145 can be locked to the shaft 146 to produce rotation in the desired direction. The shaft 146 drives the sprocket wheel 73 through gears 141 and 139. In order to obtain the correct travel of the transverse feed carriage on its return movement to bring the detent 74 into alignment with the required tooth of the spacing rack 75, the bevel gear 144 is connected to the shaft 118 by a dog-clutch (188), Fig. 5 (not shown). The clutch is operated by a bell crank lever (183) carrying a roller follower (182) which engages a cam (181) mounted on the machine frame. The length of the cam determines the extent of the return movement of the transverse feed carriage.