Patent GB-888186-A (GB)
Title: Feed box change speed transmission
IPC: F16H61/02
Filed: 1958-08-19
Abstract: 888,186. Change-speed gear and control. AMERICAN STEEL FOUNDRIES. Aug. 19, 1958 [Aug. 23, 1957], No. 26677/58. Class 80 (2). Change-mesh change-speed gearing has its various ratios established on axial sliding of certain gears by power means driving through pinions meshing racks to actuate gear striker forks. Function summary.-A vertical metal boring and turning machine, or a vertical boring mill, having a rotating work-supporting table, has its feed-box driven from the work-supporting table mechanism. A change-mesh change-speed gear giving twenty-four ratios is driven from the work-supporting table and transmits drive through gearing giving uni-directional rotation, irrespective of the direction of rotation of the input shaft, to an output shaft. Ratios in the change-speed gear are pre-selected by manual operation of a twenty-four position rotary solenoid selection device which turns a twentyfour position switch. The pre-selected ratio is then established by operation of a press-button feed-switch which sets in action a number of relays energizing individual electric motors associated with the change-speed gear striker forks. Neutral in the gearing is first obtained by sequential operation of the relays and motors, and the desired ratio later established. Each motor drives through rack-and-pinion gearing to the associated striker fork. Gearing.-Bevel gearing 40, Fig. 1, driven in one direction or the other from the rotating work-supporting table drive mechanism, rotates a shaft 20 upon which is splined for axial movement a double gear 36 meshing with either the larger or the smaller diameter portions 48, 50 of a gear cluster 52 journalled upon a shaft 32. The gear cluster 52 also meshes a double gear 58 journalled upon the input shaft 20 and meshing a further double gear 70, also journalled upon the shaft 32 and in turn meshing another double gear 56 journalled upon the input shaft 20. Gears 76, 78 are splined for axial movement upon a countershaft 26, the gear 76 being engageablewith the double gear 56 and the gear 78 being engageable with either the smaller or the larger diameter portions of the double gear 58. A gear 98 integral with the countershaft 26 meshes the larger diameter portion of a double gear 60 journalled upon the input shaft 20 and having its smaller diameter portion engageable by the larger diameter portion 88 of a double gear and clutch 84 journalled upon and axially slidable upon the countershaft 26. The double gear 84 includes positive clutch teeth 90 which can be slidden into engagement with the gear 98 integral with the countershaft 26. The larger diameter portion 88 of the double gear 84 can, as shown, be meshed by the smaller diameter portion of a double gear 96 splined for axial movement upon a shaft 28, movement downwards of Fig. 1 of the gear 96 permitting the larger diameter portion 94 thereof to be meshed with the smaller diameter portion 86 of the double gear 84. Axial sliding of the gears 36, 76, 78, 84, 96 permits a total of twenty-four ratios to be imparted to the shaft 28. A gear 112 fast thereon meshes a gear 114 in turn driving through a gear 118 and a ratchet clutch 120 to a driven shaft 30. If the rotation imparted by the gearing to the gear 112 is in such a direction that the ratchet clutch 120 overruns, then drive is alternatively transmitted through an oppositely-directed ratchet clutch 124 to a gear 126 meshed by a reversing gear 132 (as shown in Fig. 2) meshing a gear 128 fast upon the output shaft 30, which is accordingly always rotated in the same direction. An independent rapid traverse motor can drive to the shaft 30 through a gear 134, and an independent positioning motor can drive through a gear 136 to the reverse gear 132. Control.-Each of the gears 36, 76, 78, 84, 96 is slidden axially to its ratio-established or neutral position by individual electric motors 142, 144, 146, 148, 150, Fig. 9, each motor, such as the motor 142, Fig. 4, driving through a pinion 154 meshing a gear 156 fast upon a shaft 162 to a gear 164 meshing a rack 166, Fig. 2, fast with the associated gear striker fork 168. The striker forks are mounted upon pairs of rods 176, and are retained in position by spring-biased ball detents 186. Switches 194, 194a, Fig. 3 switch off the driving-motor 142 when the striker for 168 reaches the end of its travel. The other motors 144, 146, 148, 150 drive through similar arrangement of gears, racks and pinions to their striker forks, each having a similar arrangement of shut-off switches actuated by the controlling gear. The motor 150 drives a gear 234, Fig. 3, controlling the position of the double gear 78, Fig. 1, and the motor 148 drives a gear 232, Fig. 3, controlling the position of the gear 76. To prevent both these gears being moved to a ratio-established position at the same time, a mechanical interlock is provided together with an electrically-controlled safety device. The gear 234, Figs. 3, 8A, is provided with an axially-extending flange 288 having two slots 290 milled therein. Fast with the gear 232 is a flanged segment 302 having an axial rim 304. When, as shown in Fig. 3, the gear 234 has been turned anti-clockwise to one ratio-established position of the double gear 78, the rim 304 on the segment 302 coacts with the rim 288 to prevent the gear 232 being turned clockwise from its neutral position, as shown, and the edge of its toothed portion 296 similarly coacts with the toothed portion of the gear 234 to prevent its movement anti-clockwise from the position shown. If, however, the gear 234 is turned clockwise from the Fig. 3 position to the intermediate neutral position, as shown in Fig. 8A, the rim 304 on the segment 302 can slide through the slots 290 and the gear 232 can accordingly be rotated to its ratio established position. If the gear 234 is turned further clockwise to its other ratio established position while the gear 232 remains in its neutral position, the axial flange 288 again coacts with the rim 304 to prevent clockwise movement of the gear 232 away from the neutral position, and similarly the toothed portion 296 thereof again prevents movement anti-clockwise of the gear 232. The shaft of the motor 150 drives at one end through the gear 234 &c. to a rack-and-pinion, as described, and the associated striker fork actuating the double gear 78, and at the other end drives through a gear 310, Fig. 9, to a gear 312 carrying a radially projecting lug 327 which, when the associated striker fork is in its neutral position, is engaged on both sides by arms 353 pivoted on the motor casing at 352 and biased to the position shown by springs 354. Accordingly, rotation of the gear 312 and the motor 150 is prevented and the gear 78 is held in neutral position. When it is desired to actuate the motor 150 and establish one of the ratios through the double gear 78, a solenoid 338 is energized to draw a link 344 upwards of Fig. 9, the link 344 coacting with the ends of the two arms 353 which are thereby turned against their spring bias to a position where they are clear of the lug 327 fast with the gear 312. The motor 150 can then turn to the ratio-established position. When the solenoid 338 is de-energized, the springs 354 bias the arms 353 to re-engage the lug 327. On energising the motor 150 again to turn the gear 312 and the lug 327 back from the ratio established position, the lug 327 biases the arm 353 under which it now lies upwards, until it reaches the central, neutral, position shown, when it abuts the end 360 of the opposing arm 353 and the first arm 353 is returned to locking position by its associated spring 354. The desired ratios in the change-speed gear are preselected through a manually-operated twentyfour position rotary solenoid selection device controlling a twenty-four position switch. The pre-selected ratio is then established by manual operation of a press-button feed-switch 374, Fig. 11, making a circuit from a line L1 through contacts 373 and a relay coil CR-34-D to a line L2, the relay CR-34 (not shown) being of the type also operated by a second coil CR-34-P. Energization of the relay coil CR-34-D closes contacts CR-34-1 so that a circuit is completed through the closed contacts 373, closed contacts CR-31-5, one or other of two parallel contacts CR-R, CR-F, closed alternatively according to the direction of rotation of the work-supporting table, and closed contacts TDR-1 to a relay CR-30. Energization of the relay CR-30 closes contacts CR-30-1 which by-pass the contacts 373 &c. and lock the relay CR-30 in energized position. Simultaneously, the relay CR-30 closes contacts CR-30-2 in series with contacts 375 opened by the feed press-button switch simultaneously with closing of the contacts 373. If the double gear 78, Fig. 1, is now in the neutral position, the contacts 276a-1 of a switch 276a, Fig. 3, actuated by the control gear 234 thereof in a manner similar to the operation of the limit switches described above, are held closed. Accordingly, a relay CR-31 is energized, first to close contacts CR-31-1 and lock itself in. If, however, the gear 78 is not in the neutral position, then the contacts 276a-1 are open and contacts 276a-2, also actuated by the switch 276a, are closed. A circuit from the open contacts 375 is thereby made through contacts CR-31-2, closed by energization of the relay CR-31, to a reversing switch 276-1, 276-2 which supplies current, on release of the feed-button 374, through circuit connection points 370, 372 to either a relay CIL or a relay CIR. These relays close either contacts CIL-2 or CIR-2 to energize the motor 150, which accordingly rotates in the appropriate direction to restore the gear 78 to its neutral position. The contacts 276a-2 are opened and the contacts 276a-1 are then closed, to energize the relay GR-31 which is locked in, as described above. Energizing the relay CR-31 opens the normally closed contact CR-31-2, to break the circuit to the motor c