Patent GB-600903-A (GB)
Title: Improvement in grinding machine
IPC: B24B19/02
Filed: 1941-12-29
Abstract: 600,903. Grinding-machines. JONES & LAMSON MACHINE CO. Dec. 29, 1941, No. 16737. Convention date, Feb. 8. [Class 60] A grinding-machine of the general type described in Specification 478,757 is adapted for internal grinding and comprises a traversing work - carriage and a grinding-wheel carriage mounted for motion transverse to the direction of motion of the work carriage, a wheel support mounted on the wheel carriage and movable in the direction of motion of the wheel carriage between limits at one of which the wheel is in operative position, and at the other in trueing position. The machine comprises a traversing work carriage 3, Fig. 2, to which may be clamped a headstock to which the work 5 may be secured. The wheel carriage 10 is movable on rollers in a direction transverse to the traverse of the work carriage, as in the prior Specification, and is furnished with an arcuate cradle 12, Fig. 4, for adjustably supporting a wheel support fitted with a casing 20 having an arm 21 to which is pivoted a casing 22 fitted with a belt-driven shaft 44 on which the grinding-wheel is mounted. The wheel casing 22 can be swung from the position shown, in which the wheel is in grinding position, to an inner position in which the wheel is trued, by means of a pneumatic piston 73 and a pivotally-mounted cylinder 70 to the ends of which fluid pressure may be admitted by pipes 80, 81 from an electrically-actuated valve 82. To hold the casing in either of its positions on failure of the fluid pressure supply, a spring-influenced plunger 103 is provided which is normally held out of operation by fluid pressure supplied by a pipe 100 to a cylinder in which the plunger works, and is projected by its spring on the failure of the fluid pressure to engage stop dogs 106, 107 on the casing. The work is rotated and traversed from a motor 154, Fig. 1, through a train of gears 400, including a reversing clutch 405, to a shaft 401 mounted for rotation in the work supporting carriage 3 and formed as a lead screw 403 engaging a fixed nut. The shaft 401 drives through change speed gearing 410, 416 a shaft 411 which drives the work chuck 413 through change speed gearing 412. The reversing clutch 405 is controlled by a lever 407 operated by a rod 422 from a cam drum 424. Means are provided for moving the grinding-wheel towards and from the work, and the trueing device towards and from the wheel. For this purpose the wheel carriage 10, Fig. 2, is provided with a sleeve 440 engaged by the splined end of a shaft 442 which drives a long gear 561 on a shaft 562 driving a shaft 563 having threaded engagement with the wheel carriage and against which engages a part 564 of the trueing device casing 565. The forward end of the sleeve 444 engages the threaded end 445 of a shaft.446 held against rotation by an arm 447 and having its forward end 448 engaged by a threaded sleeve 449 secured to the hub of a gear wheel 451. Mounted on the sleeve 449 is a sleeve 452 to which a lever 455 is pivoted, the upper end of which is furnished with an adjustable abutment 456 riding on a cam plate 457 whereby movement of the lever effects movement of the sleeve 452 together with the shaft 446, sleeve 444, wheel carriage 10 and trueing mechanism. The wheel carriage is retracted by means of a spring 461 attached to a chain 463 engaging a sprocket 464, the motion of the sprocket being transmitted by a further chain 467 and sprocket 466. The movement of the wheel carriage is limited by the engagement of the lower end of the lever 455 with a plunger 460. Rotation of the gear wheel 451 effects the normal feed and retraction of the grinding-wheel, while rotation of the sleeve 444 produces a feed motion of the wheel carriage and a feed of the trueing mechanism. The lever 455 is operated to withdraw the wheel carriage for relief work, or clearance during an inoperative traverse, through the plunger 460 which is fitted with a cam follower 470 engaging a cam 471 carried by a rock shaft 472 and provided with a segmental gear 473 engaging rack teeth on a bar 474 pivoted to a lever 476 operated from the cam drum 424. The gear wheel 451, for effecting normal feed is engaged by a gear operated by a hand wheel 481 the hub of which is fitted with a ratchet 482 rotated step-by-step by a telescopic spring link 490 and arms 485, 486, the lower end of the link resting on an arm 491 of a rocker 492. The trueing feed is effected by rotation of the shaft 442 geared to a shaft which can be turned manually, and fitted with a ratchet wheel operated by a similar telescopic spring link 514 resting on an arm 515 on a rocker 516. Operation of the ratchet may be prevented by a latch 520 having a notch 521 engaging over a pin 522 carried by the arm 511. The opposite end of the latch 520 is fitted with a dog 523 engaged by dogs 524 adjustable on the gear 451 to free the ratchet 512. Rocking of the member 516 is effected by cams on the cam drum 424 through a link 541 and rocker arm 542 fitted with adjustable lugs 545. The wheel feed ratchet is actuated by an arm 555 carrying a plate 556 with an adjustable lug 558. The cycle of operations is determined by a drum 150 with switch actuating cams, and rotatable with the drum 424 having mechanical controls. They provide for motion between grinding and trueing positions and for an actuating impulse of the trueing mechanism when the work is at that end of the traverse where the wheel is retracted. Trueing is effected only at predetermined times, the actuating impulses at other times being ineffective. Three phase motors 151, 34 and 154 drive the cam drums 150 and 424, the grinding wheel and the work traversing and rotating mechanism respectively, while the trueing mechanism is actuated by a direct current motor 156. A diagram of connections is given.