Patent GB-190002533-A (GB)
Title: Improvements in Machines for Cutting th Teeth of Gear Wheels.
Filed: 1900-02-08
Granted: 1900-10-13
Abstract: 2533. Lake, H. H., [Brown & Sharpe Manufacturing Co.]. Feb. 8. Milling.-The machine is for cutting the teeth of spur gears, and especially spiral gears. The gear blank is fixed to the spindle 1, which has a step-by-step motion for cutting the different teeth and a continuous motion during the cutting operation when spiral teeth are being made. The cutter c, Fig. 12, is fixed to a horizontal spindle 10, Figs. 1 and 12, arranged below the spindle 1. The angle between the spindles 1 and 10 is a right-angle when ordinary spur wheels are being cut but the spindle 10 is inclined for spiral gears. The spindle 10 can be adjusted axially in the head 214, the head can be adjusted horizontally in the saddle 189, the saddle is pivotel to the carriage 11 so that the cutter may be lowered to clear the work as it is retracted, and, lastly, the carriage 11 is fed in a line parallel to the axis of the spindle 1 by a screw 32. The spindle 10 is rotated from a shaft 226, which rotates the shaft 223 by worm gearing. The shaft 223 drives the spindle 10 through bevel-wheels, the annular bevel-wheel 218 permitting the horizontal adjustment of the head 214. The shaft 226, Figs. 3 and 12, derives its motion from the main shaft 13 through gearing 17, 232 and a universal joint 228. The shaft 54, which is intermittently rotated through half a revolution, raises and lowers the saddle 189 as above described through spiral gears 198, 199. The cutter carriage is fed forward slowly, retracted rapidly, and stopped automatically by the following mechanism :-The feed-screw 32 is directly connected to a shaft on which there constantly rotate loosely in opposite directions a worm-wheel and a drum, either of which may be coupled to the shaft by a clutch actuated by a fork on the rock shaft 45. A train of spur-wheels connects the main shaft with the worm-wheel, and another train 26 &c. connects the drum to the shaft 28, which is connected by spiral gears 29 to the main shaft 13. The rock shaft 45 is operated by a pin on the carriage striking dogs on a horizontal bar actuating a transverse rock shaft which, through gearing, depresses a slide 75 carrying a hook 73. This hook draws a pin away from a cam loose on the shaft 28, and allows a spring to force the cam into gear with a clutch on that shaft. This cam rotates the shaft 54 through half a revolution by spur gearing with a Genevastop action. The shaft 54 carries the cam 53, which moves a bar operating the rock shaft 45 above mentioned. This bar derives part of its motion from a spring, and, when it is desired to stop the machine, the bar can be stopped so that the spring is inoperative. This is done automatically thus:- The cam 53 reciprocates a vertical rack which feeds a slide step - by - step till it rocks a vertical shaft, and allows a spring bolt to arrest the motion of the bar above mentioned. The slide can be set so that the spring bolt acts after any desired number of teeth have been cut, a bell indicating that the machine has stopped. Special safety devices are described which prevent the workman from reversing the machine by hand at the wrong time, and to actuate positively as well as indirectly certain parts of the reversing-mechanism. The spindle 1 is rotated during the cutting operation by the following mechanism :-The spindle 1 is fixed to a worm-wheel 159, actuated by a worm 158 geared to the spindle 170. This spindle slides in a sleeve 171, so that the spindle 1 may be raised or lowered by hand without affecting the rotating mechanism. The spindle 170 is actuated by the spindle 157 in the same axial line by bevel-wheels 166, 167, 169. The wheels 167 are carried by a rotating box 168. The shaft 157 carries two loose wheels, namely, the bevel-wheel 156 and worm-wheel 161, either of which may be connected to the shaft by the clutch 160. The wheels 156 and 161 are connected to the feed-screw 32 by trains of gearing, including change gearing, a great variation in speed being thus obtainable. The spindle 1 is rotated step-by-step by the following mechanism :-The box 168 carries a worm-wheel 175 connected by a train of gearing 179, 181 &c. to a shaft 182. A spur-wheel on this shaft gears with a wheel fixed to the same shaft as the mutilated gear 261, Fig. 19. This wheel 261 is started and stopped gradually by pins 264, 265, which are fixed to the wheel 260 and act on a tooth 266 of the wheel 261 when the spur-wheel 260 comes opposite the gap 271 and ceases to drive the wheel 261. The shaft 112 of the wheel 260 is in a line with the constantly-rotating shaft 28, and is clutched to it by an arm on the rock shaft 122. The shaft 122 is actuated by a cam 133 on the shaft 54. In modifications, the blank support may reciprocate and rise and fall instead of the cutter.