Patent GB-383321-A (GB)
Title: Improved method of and machine for tightening screw threaded elements or the like
IPC: B60B31/02
Filed: 1931-08-11
Abstract: 383,321. Screwing-up bolts and nuts. BUDD WHEEL CO., 2500, Hunting Park Avenue, Philadelphia, U.S.A.-(Assignees of Farr, W. H. ; Eksergian, C. L. ; and Smith, O. E. ; 12141, Charlevoix Avenue, Detroit, Michigan, U.S.A.) Aug. 11, 1931, No. 22715. Convention date, Sept. 5, 1930. [Class 83 (iii).] A machine for tightening screw-threaded elements, particularly for trueing up wirespoked vehicle wheels, is arranged to tighten, by rotation thereof, a number of elements simultaneously by means of fluid pressure, the work being preferably indexed before a further number of elements are simultaneously tightened. The pressure fluid used is preferably compressed air. Work holders.-The machine comprises an indexable work-table 18, Fig. 2, rotatably supported by ball bearings 23 on a cylindrical base 22 carried by a bed 250. Radial dogs 25 are movable outwards on the table, to grip and centre the interior of a wheel rim 10, by means of radial plungers 88 actuated by a bevelled shoulder 83 on a plunger 80 which is moved axially by a fluid-pressure cylinder 81 and which simultaneously actuates means for clamping the rim and hub 11 axially on the table. Springs 28 collapse the dogs 25 when released, and shoulders 24 on the dogs limit their outward movement. The wheel rim is located initially on the table by an annular shoulder 19 and by a pin 91 passing through an opening in the rim. Guideplates 32 are secured to the table by screws 33 and have recesses for receiving the dogs. The hub 11 of the wheel rests on a floating support 35<1> which is guided between an annular extension 31 of the table and an end-plate 37 secured thereto, a spring 39 normally keeping the support in a raised position. A wearresisting plate 41 receives the hub, and holes 42 in the plate and support carry spring pins 90 which enter holes in the hub to locate it thereon. The rim and hub are clamped on the table by a head 54 having an internal bushing 45 for engagement with an extension 44 on the support 35<1> and a number of pins 47 which depress the pins 90 and engage the holes in the hub, spherical shoulders 48 being provided on the pins to coact with similar seats on the holes. Arms 50 are pivoted at 51 to lugs 52 on the head 54 and have arcuate flanged ends 60 for engagement with the rim 10. The lugs 52 are secured in the head by pins 61 which allow easv removal of the lugs and arms for replacement by others to suit different sized wheel rims. The head is carried by the piston-rod 64 of a fluid-pressure cylinder 62, Fig. 1, the rod having a plate 74 secured thereto provided with cam apertures 77 for co-operation with curved links 72 pivoted to the head at 70. The lower ends of the links are pivoted at 79 in apertures in segmental dogs 78 which are moved thereby into engagement with a flange 85 on the piston-rod 80 when the head is lowered on the work. The cylinder 62 is carried by a bracket 63 on a pillar 253 attached to the bed 250, clamps 257 being provided for securing the bracket and pillar. Driving devices, yielding; tap-spindle feeds.-A number of brackets 258 are secured to the bed 250 and carry tools for operating on diametrically opposed spoke nipples to ensure evenly distributed stressing of the wheel during tensioning. Each bracket has a plate 259, Fig. 12, adjustably secured thereto by screws and slots, and supports 262 on the plate carrying a pair of guide rods 263. The screwing- up tool 315 is rotated by a fluid-pressure motor 316 whose casing is connected at 318 to a fluidpressure cylinder 305. The piston-rod 302 of the cylinder is secured at 304 to an end support 262 so that the cylinder and motor may be reciprocated on the guide rods to feed the tool. A spring 307 withdraws the tool and fluid is supplied to the cylinder and motor simultaneously through passages 311, 312, and a flexible connection to a pipe 309. Brackets 317 on the motor and cylinder engage the guide rods. Indexing mechanism.-An annular ring of teeth 21 on the work-table 18 is engaged by a pinion 200, Fig. 6, for bringing successive nipples opposite the screwing-up-tools. The pinion is keyed to a shaft 209 which has also keyed thereon a friction clutch 215 for cooperation with a clutch 212 rotatable on the shaft. A ratchet wheel 211 is removably secured to the clutch 212 and is engaged by a pawl 210 carried by an arm 207 pivoted at 232, Fig. 8, on the shaft 209 and also pivoted at its lower end to a connecting-rod 206. The connecting-rod is pivoted to a crosshead 203 slidable on guide rods 204 and pivoted to the piston-rod 202 of a fluid-pressure cylinder 201. The friction clutch 212, 215 is engaged, in opposition to a spring 216, by a cam-ended hand lever 220 acting through a dished plate 217 on the part 215. The ratchet wheel is locked in the indexed position by a pin 224 on a bar 225 slidable on guide rods 226 and normally pressed by springs 229 into engagement with one of a number of recesses 223 on the ratchet. A number of shrouds 241, one for each hole 223, are adjustably attached to the clutch 212. In operation, fluid admitted to the cylinder 201 raises the pawl 210, which is prevented from engaging the ratchet until a spring plunger 234 thereon has acted on an inclined surface on a pin 240 attached to the bar 225 to withdraw the pin 224 from its recess 223. After this withdrawal the pawl rides off the shroud and rotates the ratchet, the plunger 234 going past the pin 240 and the pin 224 resting on the surface of the ratchet. When the succeeding recess 223 comes opposite the pin 224, the pin snaps into the recess and prevents further rotation of the table, the pressure in the cylinder 201 being so arranged that the piston may stall without injury to the indexing mechanism until it is reversed. To vary the angular movement of the table during indexing, the ratchet 211 is replaced by one having differently spaced teeth and recesses 223. Operation. Fluid pressure is supplied to the machine by a pipe 400, Fig. 1, connected to pipes 402, 403, 404 for operating the clamping head 54, the tool rotating and feeding means 316, 305 and the clamping cylinder 81 and indexing cylinder 201 respectively. Actuation of a hand-lever 94 admits fluid to the cylinder 62 to raise the head 54 clear of the table, as shown in Fig. 2, to allow a wheel consisting of rim, hub, and loosely assembled spokes to be inserted on the table 18. The head 54 is then lowered, the arms 50 engaging the rim 10 and the plate 74 passing down the links 72 to cause the dogs 78 to engage the neck 84 of the pistonrod 80. Fluid is then admitted to the cylinder 81 by a valve 412 to cause the rod 80 to draw down the head 54, against the spring 39, the arms 50 being rocked about their pivots, and the dogs 25 being expanded to grip the wheel rim whilst the hub is centred and gripped by the extension 46 of the head and the pins 47. The clutch 212, 215 is next released by the hand-lever 220 to allow the work to be rotated by hand to position the nipples opposite the tools and then re-engaged. A valve 408 is then actuated to admit fluid to the rotating and feeding motors 316, 305 for tightening the nipples, the motors 316 continuing to rotate until they are stalled and a reducing valve 405 being provided in the pipe 403 to allow the pressure to be adjusted so as to vary the degree of tightening applied to the wheel. The valve 408 admits fluid to two oppositely arranged tools simultaneously, but if more than two tools are to be used together, a valve 408 is provided to supply each opposed pair of tools and the control is effected jointly by a main valve 406 and a chain 407. To withdraw the tools, the pressure thereto is reversed and during withdrawal a dog 416 on one cylinder 316 engages a lever 415 to actuate a valve 413 through a link 414, thereby admitting fluid to the cylinder 201 to effect indexing of the work. When the cylinder 201 has stalled, the tools are fed forward again, the dog 416 releasing the lever 415 and a spring 420 reversing the supply to the cylinder 201. When all the spokes have been tightened the clamp is released by the cylinder 81 and the head 54 is raised by the cylinder 62 to permit replacement of the wheel.