Patent GB-574631-A (GB)
Title: Improvements relating to machines for grinding the teeth of gear wheels
IPC: B23F1/02
Filed: 1944-05-05
Abstract: 574,631. Grinding gear-wheels. GEAR GRINDING CO., Ltd., and ORCUTT, A. H. May 5, 1944, No. 8542. [Class 60] A machine for grinding the teeth of gearwheels, wherein a formed grinding-wheel is reciprocated between the tooth surfaces and the work-piece is indexed to bring successive teeth into the grinding position, the grinding- wheel being trimmed periodically, has means whereby the feed movements of the work piece and the wheel trimming periods are controlled automatically. The machine comprises a bed a, upon which is a slide b carrying the grinding-wheel c and reciprocated horizontally; the toothed wheel to be ground is carried by a spindle e in a headstock d. The spindle e is carried by a slide i movable vertically in guides k in the headstock, and at the rear end the spindle carries an index plate operated by a shaft m. The slide i is adjustable by a screw g movable by a manually operable member f, and connected to the slide i, for automatic feed, through a piece o connected by a link p to a forked crank arm q, which is pivoted to the slide, the axis of the pivot being eccentric to that of the connection of the arm to the link p; the eccentricity of the axes determines the amount of the automatic feed. The crank arm is actuated, through a link x, by a rack w slidable in a housing or box r and moved by a pinion v on a spindle s carrying a dial t manually operable by a handle 6 ; the spindle s also carries a notched disc y movable, for automatic feed, by an arm 2 pivoted in the box r. The arm carries a pawl 3 engaging the disc y, a retaining pawl 5, preventing reverse rotation of the disc, also being provided, and both pawls being movable to inoperative position to permit of manual operation. The arm 2 is moved automatically in the direction to feed the work by a spring 11 in a tube 13 connected by a link 12 to a solenoid 10, which is energized to hold the arm retracted against the action of the spring 11 through two contacts 20 closed by a piece 19; the piece 19 is movable by a striker 16 on the index plate l, which thus operates the feed once for each complete rotation of the index plate, the feed diminishing at each actuation as the crank arm q approaches its vertical position. The grinding-wheel is trimmed at intervals by mechanism h, the slide b being retracted for this purpose by mechanism operated by a solenoid, the circuit of which is controlled by strikers 23 on the dial t, which operate, through a plunger 29, a contact member 27. The member 27 normally engages a contact 25 in the circuit of the solenoid 10, but when moved, opens that circuit and engages a contact 26 in the circuit of the solenoid for controlling the trimming ; after completion of the trimming, the machine is restarted by a push-button and the contact 25, 27 is again restored by a solenoid 35 which moves a pivoted arm carrying the plunger 29, the solenoid 35 being energized momentarily by a switch 37 moved by a tappet 38 on the slide b. The attendant is warned when grinding is approaching completion by a lamp &c. controlled by a switch 40, 41, 42 actuated by strikers 44, 45 on the inner periphery of the dial t ; the striker 44 operates when the final trimming stage has been reached, and the striker 45 operates to indicate that the grinding operation is completed.