Patent GB-491118-A (GB)
Title: Improvements in and relating to a dividing apparatus for grinding machines for grinding of toothed wheels, grooved shafts or the like
IPC: B23F23/08
Filed: 1937-09-21
Abstract: 491,118. Grinding toothed wheels &c. ZAHNRADFABRIK FRIEDRICHSHAFEN AKT.-GES. Sept. 21, 1937, No. 25623. Convention date, Sept. 25, 1936. [Class 60] [Also in Group XXII] In an indexing mechanism for use in machines for grinding toothed wheels, grooved shafts, &c., a notched dividing plate is engaged by a brake device when the index stop is disengaged from the dividing plate to allow a dividing operation to be effected, the brake being removed as the index stop is reengaged. In a mechanism for grinding straight teeth shown in Figs. 1 and 2, the notched dividing plate 6 on the centre shaft 3 is held in position during the grinding of one tooth space by a stop 15 carried by a lever 16 pivoted to an arm 9 on the sliding work-table 2. An adjustable brake shoe 20 normally out of contact with a disc 8 on the shaft 3 is carried by a lever 17 which is pivoted coaxially with the lever 16 and is secured to it by a pin 19. The pin 19 is connected by a link 25 to a shaft 26 carrying a block 30 slidable against the resistance of a spring 28 in a projection on the table 2. A spring-controlled arm 36 having a trapezoidal head 35 is pivoted on the machine bed 1 in the path of the block 30. A pawl 47 engaging a toothed feed disc 7 on the shaft 3 is pivoted to a lever 49 rotatably mounted on a pin 50 projecting centrally from the shaft 3. A cam 58 on the bed 1 is engaged by a roller 57 on a spring-pressed shaft 53 which is slidable in the table 2 and is pivoted to a link 52 adjustably secured to an arcuate slot 51 in the lever 49, the centre of the slot 51 being at the pivot pin 531. When the table is displaced in the direction of the arrow I, Fig. 2, the block 30 lifts the arm 36 and the lever 49 is moved anticlockwise as the roller 57 passes over the cam 58. On the return movement of the table, the block 30 pushes the arm 36 downwards against a stop 39 and then passes over the head 35 thereby operating the levers 16, 17 to disengage the stop 15 and to engage the brake shoe 20 with the disc 8. Simultaneously, the cam 58 operates the lever 49 to rotate the feed disc 7 and shaft 3. When the block 30 leaves the head 35 the brake shoe is withdrawn from the disc 8 and the shaft 3 is free while being finally brought into position by the engagement of the stop 15 with the disc 6. In a modification, the cam 58 is pivoted on the bed 1 and is moved into and out of the working position by an arm on the table 2. In another modification, the stroke of the pawl 47 is adjusted by the rotation of a variable-pitch cam engaged by the shaft 3. The Specification as open to inspection under Sect. 91 comprises also a mechanism suitable for grinding helical teeth shown in Figs. 11 (Cancelled) and 13 (Cancelled) in which the movement of the table 2 is caused to rotate the shaft 3 by the engagement of a pin 134 on a transverse slide 133 with an adjustable inclined guide 135. The slide 133 is connected by steel bands 130, 131 to a roller 128 carrying an arm 129 supporting a lever 126 having a tooth 115 engaging the notched dividing plate 106. At the end of the movement of the arm 129 in the direction IV, Fig. 11 (Cancelled), a projection 121 on the lever 126 engages a cam 114 on a spring-controlled lever 111.. The tooth 115 is consequently disengaged from the plate 106 and a spring 125 between the arm 129 and lever 126 causes a brake shoe 113 on the lever 111 to be pressed into engagement with a disc 108 on the shaft 3. After passing the cam 114 the lever 111 is released and the tooth 115 engages the plate 106. On the return movement the projection 121 passes under the cam 114 and lifts the lever 111. In a modification shown in Fig. 14 (Cancelled), a lever 141 and an arm 129 operated as in the mechanism shown in Figs. 11 (Cancelled) and 13 (Cancelled), carry a lever 146 having a tooth 145 engaging the dividing plate 166 and a projection 151 adapted to engage a projection 152 on a lever 155 pivoted to a lever 158 mounted coaxially with the arm 141, the levers 146, 155 being subjected to the tension of springs 148, 157. When an adjustable screw 147 on the lever 141 strikes a pivoted spring- pressed lever 163, the lever 158 is turned by the engagement of an adjustable bolt 161 on the lever with a guide slot in the lever 163. The lever 155 consequently lifts the lever 146 146 to disengage the tooth 145 and to allow a spring 176 to move a lever 171 to press a brake block 169 against a brake disc 168 secured to the centre shaft. This subjectmatter does not appear in the Specification as accepted.