Patent GB-520395-A (GB)
Title: Improvements in or relating to broaching machines
IPC: B23D37/06
Filed: 1938-10-20
Abstract: 520,395. Broaching. CINCINNATI MILLING MACHINE CO. Oct. 20, 1938, No. 30370. Convention date, Oct. 27, 1937. [Class 83 (iii)] [Also in Group XXIX] The machine comprises a reciprocating broach-carrying ram 13, Figs. 1, 2, a pair of spaced work holders 22, 23 adapted to be moved toward and away from the ram, and an intermediate reversible device 353 for receiving work from one holder and transferring it to the other. The holders are mounted on intergeared shafts 101, 312 for movement in opposite directions through 90 degrees. Broaching is effected with a holder in the vertical position, and loading and unloading when a holder is in a horizontal position. The ram is 13 hydraulically operated and carries broaching means 14, 16 which operate respectively on the work in holder 22 when moving outwardly and on the work in holder 23 on the return stroke. The device 353 is mounted eccentrically on a spindle geared to the shaft 101 so that the work is inverted during transference. The holder 22 has a bottom 109 carried by pivoted links 110, one of which includes a lever 112 carrying a roller co-operating with a cam 114 mounted on a spindle carrying a pinion gearing with a rack plunger 118. The rack is manually operable by a handle 125. Work is fed from a conveyer 108 on to'the bottom 109, when the latter is in the raised position, by a hydraulically operated member 207 and the handle 125 is then operated to allow the bottom to move laterally downward until a lug thereon engages a bar to operate bell-cranks 144 to engage the work and force it against stop 143. When the holder is swung upward a number of spring-pressed plungers, which were previously engaged by fixed abutments on the machine, are freed to effect movement of various clamping and backing up members to engage the work. A pivoted lock 232 operated by an automatically controlled hydraulic cylinder 235 engages lug 237 on the holder to force the holder against a stop 504 and lock it in the cutting position. As the holder is swung down after cutting, the rack 118 and the plungers referred to engage various fixed abutments and are moved to effect raising of the bottom into contact with the work and release of the clamping means. An end work stop 229, Fig. 8, is disengaged when the bottom is lowered but abuts the work when the bottom is raised. The holder 23, Fig. 16, is provided with four work-clamps 325 mounted on rods 328 making tongue and groove engagement with cams 333 connected to actuating racks geared to a pinion 337 engaging a spring pressed rack 338 abutting a cam 340 on a shaft 341 with an operating handle 342 and a pinion 343 engaging a rack 334. When a work-piece has been fed to the holder by the hydraulically operated member 366, Fig. 1, cam 340 is manually operated to allow spring 339 to effect clamping of the work. The holder is locked in the cutting position by an automatically operated lock 339. Backing- up plungers are provided in the holder to take the thrust of teeth 20 of the cutter. When the holder is swung down, cams on uprights 313, 314 effect release of the backing-up plungers and rack 344 engages plate 347 to release the clamps 325. A stop 318, Fig. 21, is pushed under the work by pin 322 when the holder moves to the cutting position. The hydraulic cylinder 24, Fig. 11, 12, is integral with the ram 13 and contains a stationary piston mounted on a rod through which fluid is delivered. Manual operation of lever 85 in an anti-clockwise direction moves the valve 72 to effect movement of reversing valve 39 with consequent movement of the ram to the right and removal of dog 274 from under piston 275, which consequently moves downwards, and pawl 283 is moved into locking engagement with a member 284 on the control member of the motor for oscillating the holders. At the end of the stroke a dog raises the rack 83 to stop the ram, and a dog 446 raises plunger 275 to cause removal of interlock pawl 283. During this stroke the holder 22 has been loaded and unloaded by moving handle 220 to depress valve 210. When the handle is released the valve and loader are returned. During this movement plunger 416 is depressed by spring 417 and pawl 422 locks member 284. Hand lever 286 is now operated to move valve 287 to the right. Valve 406 which has a lostmotion connection with the crank 405 now moves to the right and piston 397 moves to unlock holder 23, pawl 415 moves to lock lever 220, and plunger 94'is withdrawn and bell crank 92 moves to lock handle 85. As the piston rises, trip lever 407 moves plunger 408 to the right to effect movement of valve 303 to the right with consequent operation of the hydraulic motor 289 to rotate the work holders and transfer cage. As holder 22 approaches its cutting position it moves valve 252 through plunger 254 and bell crank 255 to cause actuation of lock 232, removal of lock 428 from handle 379, removal of interlock 91 from handle 85 and movement of plunger 259 with consequent movement of plunger 268 to the right to block the return flow from the motor to stop it. Lever 85 is now operated to move the ram to the left and during this stroke holder 23 is loaded and unloaded. A relief valve for the cylinder of the hydraulic ram comprises a plunger 46 normally held by a latch 50. At a certain pressure spring-loaded valve 48 lifts and latch 50 is withdrawn to allow plunger 46 to rise and interconnect pressure line 44 and relief line 59. The valve plunger may be relatched by manual depression of the plunger. The work feeding device, Fig. 15, comprises a piston 365 attached to a T-member 366 with pivoted fingers 367, 368 adapted to pull one work piece and push the other and pass freely over the work in one direction of movement. The holder 22 is provided with an end work stop 229, Fig. 8, which is disengaged when the bottom 109 is lowered and will abut the work when the bottom is raised.- The upper holder has a stop 318, Fig. 21, which is pushed under the work by pin 322 when the holder moves to the cutting position.