US2864305A - Power presses - Google Patents

Description

Dec. 16, 1958 w. F. GOLDING POWER PRESSES 4 Sheets-Sheet 1 Filed June 25, 1956 r u. I i" w. F. GOLDING Dec. 16, 1958 POWER PREgsE's 4 Sheets-Sheet 3 Filed June 25, 1956 4 Sheets-fieet 4 W. F. GOLDING POWER PRESSES Dec. 16, 1958' Filtd June 25, 1956 ilnited States POWER PRESSES William Frank Golding, Bristol, England Application .l'une 25, 1056, Serial No. 593,606

Claims priority, application Great Britain June 24, 1955 4 Claims. (Cl. 100-286) This invention relates to power presses.

The main object of'this invention is to provide an improved drive means for the movable platen of a'power press.

One of the more particular objects of this invention is to provide a toggle drive means for a movable platen of relatively large area and to' provide means for equally distributing the forces transmitted to a plurality of toggles.

Other more particular objects of this invention are to provide individual drive means for opposite hand toggles together with means for ensuring'that the opposite hand toggles are equally loaded; means for ensuring that, if one of the individual drive means should suffer a mechanical failure, the toggles driven thereby are neverthe- I less maintained in the same operative position as the toggles having the still functioning drive, and means for stopping the press in case of general over-loading or in case of an over-loading of one of said individual drive means.

According to this invention I provide a power press comprising a frame, a fixed platen secured to the frame, a movable platen supported on said frame for reciprocating motion relative to said fixed platen, at least two operating shafts each connected to said movable platen through a means for converting the rotation of said operating shaft into said reciprocating motion of said movable platen, a positive torque-transmitting means between said operating shafts, an input shaft, and individual slip-permitting drive means between said input shaft and each of said operating shafts.

Constructional embodiments of a power press according to this invention will now be described with reference to the accompanying drawings wherein:

Fig. l is a side elevation of the press.

Fig. 2 is a section on the line 11-11 in Fig. 1.

Fig. 3 is a section on the line III-III in Fig. 2.

Fig. 4 is a fragmentary plan view of a detail of a slip permitting tooth structure which may comprise a portion of the press drive.

Fig. is a section on the line VV in Fig. 3.

Fig. 6 shows a more detailed partial view of Fig. 1 together with a circuit diagram.

Referring to Figs. 1 and 2 there is shown an up-stroke press comprising a frame 1 built up from a base 2 connected to a head or fixed platen 3 by upright members 4 embodying guides 5 supporting a movable platen 6 for vertical reciprocating motion.

The platen 6 is driven from an input shaft 7 journalled in a front bearing 8 secured to the front end of the base 2 and in bearings in a housing 9 mounted on the base 2. Between the bearing 8 and the gear box 9 the input shaft has mounted thereon an electro-magnetic clutch and brake assembly 11 comprising a driving member or flywheel 12 freely rotatable on the shaft 7, a driven member 13 secured to the shaft 7, and a brake magnet 14 secured to the bearing 8.

The input shaft 7 is adapted to drive the platen 6 r 2,804,305 Patented Dec. i6, @958 through the intermediary of a front drive F and a rear drive R.

Referring to the front drive F, there is provided a dental clutch 20 comprising a driving member 21 splined to the shaft 7 in a manner permitting axial movement and having teeth 22 standing in torque transmitting engagement with teeth 24 of a driven member 23 journalled on the shaft 7. The drive transmitting surfaces of the teeth 22, 24 are ramp surfaces so inclined relative to the direction of rotation of the shaft 7 (as indicated by the arrow 25) that under the driving torque the teeth 22 tend to ride up the teeth 24- and the driving member 21 tends to be pushed out of engagement with the driven member 23 against the pressure of a spring 26 situated between the driving member 21 and a collar 27 splined to the shaft 7 in a manner permitting axial motion. The collar 27 is supported axially by a thrust bearing 28 and a nut 29 seated on a screw-threaded boss 31 forming part of the housing 9. The pressure of the spring 26 is adjustable by rotating the nut 29, and to effect such rotation the latter is formed integrally with a toothed gear-wheel 32 meshing with a toothed gear-wheel 33 secured to a shaft 34 journalled in the housing 9 and protruding to the outside thereof where the shaft 34 is provided with a square end 35 for engagement by a'key. The shroud plates 36, 36'are of suflicient diameter to embrace the gear-wheel 32 where meshing with the gear-wheel 33 to thereby retain the gear-wheel 33 in mesh with the gear-wheel 32 when the nut 29 is caused to move axially by rotation of the shaft 34. The latter is of course also moved axially by this action, and annular indicia 37 on the shaft 34 indicate the amount of adjustment effected. The shaft 34 is provided with a serrated collar 38 engaged by a latch 39 pivoted to the housing 9 by a pin 41 and pressed into engagement with the serrations of the collar 38 by a spring 42. The latch 30 is provided with an extension 43 for beingmanually pushed out of engagement with said serrations prior to the shaft 34 being rotated. Revetting to the dental clutch 20,'the driving member 21 is provided with a circumferential groove 44 engaged by a roller 45 provided on a lever 46 secured to a shaft 47 extending transversely through the housing 9 and journalled therein. Outside the housing 9 the shaft 47 has secured thereto a lever 48 adapted to actuate a switch 49. The setting of the nut 29 is made such that the switch 49 is actuated upon occurrence of an excess torque and prior to the teeth 22, 24 of the members 21, 23 going completely out of engagement. The switch 49 is situated in an electrical circuit serving the electro-magnetic clutch and brake assembly ll. The driven member 23 of the dental clutch 20 is provided with a worm 51 meshing with a worm wheel 52 secured to a crank shaft 53 extending transversely through the housing 9 and supported in bearings therein. The end portions of the crank shaft 53 are supported in bearing brackets 54 and 55 mounted on the base 2. The crank shaft 53 is provided with two crank pins 56, 57 disposed on opposite sides of the housing 9 and connected by connecting rods 58 to two toggle linkages 59 supporting the front end of the platen 6 on the base 2. Each toggle linkage 59 comprises a lower link 61, an upper link 62, a pivot pin 63 between the link 61 and the base 2, a pivot pin 64 between the links 61, 62, and a pivot pin 65 between the link 62 and the underside of the platen 6. The connecting rods 58 are connected to the pins 64. At one of its ends the crank shaft 53 has secured thereto a gear-wheel 66.

Referring to the rear drive R, there is provided a dental clutch 70 comprising a driving member 71 splined to the shaft 7 in a manner permitting axial movement and having teeth 72 standing in torque transmitting engagement with teeth 74 of a driven member 73 journalled on the shaft 7. The drive transmitting surfaces of the teeth .3 72, 74 are surfaces so inclined relative to the direction of rotation of the shaft 7 (as indicated by the arrow 25) that under the driving torque the teeth 72 tend to ride up the teeth 74 and the driving member 71 tends to be pushed out of engagement with the driven member 73 against the pressure of a spring 76 situated between the driven member 71 and a collar 77 splined to the shaft 7 in a manner permitting axial motion. The collar 77 is supported axially by a thrust bearing 78 and a nut 79 seated on a screwthreaded boss 81 forming a part of the housing 9. The pressure of the spring 76 is adjustable by rotating the nut 79, and to effect such rotation the latter is formed integrally with a toothed gear-wheel 82 meshing with a toothed gear-wheel 83 secured to a shaft 84 journalled in the housing 9 and protruding to the outside thereof where the shaft 84 is provided with a square end 85 for engagement by a key. The shroud plates 86, 86 are of sufiicient diameter to embrace the gear-wheel 82 where meshing with the gear-wheel 84 to thereby retain the gear-wheel 83 in mesh with the gear-wheel 82 when the nut 79 is caused to move axially by rotation of the shaft 84. The latter is of course also moved axially by this action, and annular indicia 87 on the shaft 84 indicate the amount of adjustment effected. The shaft 84 is provided with a serrated collar 88 engaged by a latch 89 pivoted to the housing 9 by a pin 91 and pressed into engagement with the serration of the collar 88 by a spring 92. The latch 89 is provided with an extension 93 for being manually pushed out of engagement with said serrations prior to the shaft 34 being rotated. Reverting to the dental clutch, the driving member 71 is provided with a circumferential groove 94 engaged by a roller 95 provided on a lever 96 secured to a shaft 97 extending transversely through the housing 9 and journalled therein. Outside the housing 9 the shaft 97 is secured thereto a lever 98 adapted ot actuate a switch 99. The setting of the nut 79 is made such that the switch 99 is actuated upon occurrence of an excess torque and prior to the teeth 72, 74 of the members 71, 73 going completely out of engagement. The switch 99 is situated in series with the switch 49 in said electrical circuit serving the electromagnetic clutch and brake assembly 11. The driven member 73 of the dental clutch 70 is formed integrally with a worm 101 meshing with a worm wheel 102 se- 7 cured to a crank shaft 103 extending transversely through the housing 9 and supported in bearings therein. The end portions of the crank shaft 103 are supported in said bearing brackets 54 and mounted on the base 2 the crank shaft 103 is provided with two crank pins 106, 107 disposed on opposite sides of the housing 9 and connected by connecting rods 108 to two toggle linkages 109 supporting the rear end of the platen 6 on the base 2 each toggle linkage 109 comprises a lower link 111, an upper link 112, a pivot pin 113 between the link 111 and the base 2, a pivot pin 114 between the links 111, 112, and a pivot pin 115 between the link 112 and the underside of the platen 6. The connecting rods 108 are connected to the pins 114. At one of its ends the crank shaft 103 has secured thereto a gear-wheel 116 which meshes with the gear-wheel 66 of the front drive F.

The drives F and R are identical but of opposite hand. The crankshafts 53 and 103 are parallel and rotate in opposite directions as indicated by the arrows 120 and 121 respectively. The worms and worm wheels 51, 52 and 101, 102 are so arranged that the thrust loads on the worms 51, 101 act against one another, and a friction ring 122 is provided between the driven members 23, 73 to take this thrust.

In operation, the flywheel 12 is rotated by means of a belt drive from an electric motor (not shown). The normal setting of the switches 49, 99 is such that the flywheel 12 is electro-magnetically connected to thedriven member 13 and the consequent rotation of the input shaft 7 is transmitted through the front and rear drives F, R. The action of the crank shafts 53, 103 and the connecting rods 58, 108 causes the linkages 59, 109 to flex in equal and opposite hand manner and thus raise and lower the platen 6. Fig. 1 shows the platen in the raised position.

The in- series switches 49 and 99 are adapted, upon being actuated by the levers 48 and 98, respectively, to act upon said electrical circuit in such a way that the electro-magnetic connection between the flywheel 12 and the driven member 13 is disestablished while establish ing an electro-magnet connection between the driven member 13 and the brake magnet 14. The torque of the input shaft 7 is transmitted through the two dental clutches 20, 70, and since the crank shafts 53, 103 are geared to gether by the gears 66, 116, the torque transmitted by each of the crank shafts 53, 103 is the mean of the torque transmitted by the two dental clutches 20, 70. There fore, in case of uneven loading between the front and the rear of the platens 3, 6, there will be no tilting of the platen 6.

In case of a mechanical failure in the torque transmitting members of the front drive F, the dental clutch of the rear drive R becomes subject to overload and acts through the levers 96, 98 on the switch 99 to stop the press. Failure in the torque-transmitting members of the rear drive R causes a corresponding action through the dental clutch 20 of the front drive F.

In case of overload of the press as a whole, as by placing too thick material between the platens 3, 6, the press is stopped by simultaneous action of the dental clutches 20, 70.

The connection between the switches 49, 99 and the electro-magnetic clutch and brake assembly 11 will now be described in detail with reference to Fig. 6.

The assembly 11 comprises an annular clutch magnet secured to one side of the flywheel 12 and electrically connected by a cable 121 leading through a hole in the web of the flywheel 12 to collector rings 122 provided on an insulating member 123 secured to the flywheel 12 at the other side thereof. The collector rings 122 cooperate with brushes 124 mounted in a brush holder 125 secured to the adjacent part of the frame 4.

The driven member 13 comprises a flange 127 supporting an armature ring 128 facing the clutch magnet 120 and an armature ring 129 facing the brake magnet 14. The ring 128 is rigidly connected to pins 130 ex tending in axially slidable manner through the flange 127. The ring 129 is correspondingly connected to pins 131.

It will be seen that when the clutch magnet 120 is energised whilst the brake magnet is de-energised, the ring 128 is attracted by the clutch magnet and frictional driving connection is established between the clutch magnet 120 and the ring 128, the drive being transmitted through the pins 130 to the driven member 13. Alternatively, when the brake magnet 14 is energised whilst the clutch magnet 120 is de-energised the ring 129 is attracted by the brake magnet 14 and the driven member 13 is held against rotation by frictional contact between the ring 129 and the brake magnet 14.

The electrical connection between the switches 49. 99 and the assembly 11 is constructed as follows: The

. switches 49, 99 are situated in series in a circuit 132. A

relay 133 comprises a coil 134 situated in the circuit 132 in series with the switches 49, 99. Further, the relay 133 comprises a chage-over switch provided with change-over terminals 136, 137. When the coil 134 is nected between the brake magnet 14 and the terminal 137 is broken. The switch 135 is spring-biased to establish a connection through the terminal 137, so that when the coil 134 is deenergised by either of the switches 49,

99 being opened, the supply 138 is connected through the terminal 137 to the circuit 140 and the brake magnet 14 is energised while the clutch magnet 120 is de-energised.

The switches 49, 99 are biased into the closed position and are opened by the levers 48, 98 in case oftoverload through the dental clutches 20, -70 as described with reference to Figs. 3, 4, and 5.

What I claim and desire to secure by Letters Patent is:

1. A power press comprising a frame, a fixed platen secured to the frame, a movable platen supported on said frame for reciprocating motion relative to said fixed platen, at least two rotatable operating shafts each connected to said movable platen through a means for converting the rotation of said operating shafts into said reciprocating motion of saidmovable platen, an input shaft connected to each of the operating shafts through individual slip-permitting drive means, the operating shafts being connected together by positive torque-transmitting means independently of the connection between the input shaft and the operating shafts, means for driving the input shaft and including a clutch, a torqueresponsive member in each of said slip-permitting drive means, said torque-responsive member being movable in accordance with variations in the torque transmitted and being connected to said clutch to disengage the latter 6 when the torque transmitted by either of said slip-per mitting drive means exceeds a predetermined maximum.

2. A power press according to claim 1, comprising resilient means positioned to apply a load to oppose the movement adopted by said torque-responsive member when the torque increases.

3.' A power press according to claim 2, comprising means for adjusting the load exerted by said resilient means.

4. A power press according to claim 1, comprising a brake for the input shaft, and means for automatically engaging said brake when said clutch is disengaged.

"References Cited in the file of this patent UNITED STATES PATENTS 1,108,187 Klocke Aug. 1914 1,832,960 Barrows et al Nov. 24, 1931 1,938,720 Preble Dec. 12, 1933 2,378,062 Byerlein June 12, 1945 2,467,426 Cuttat Apr. 19, 1949 2,522,451 Johansen Sept. 12, 1950 2,577,641 Wissman Dec. 4, 1951 FOREIGN PATENTS 885,414 France May 24, 1943

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