Patent GB-353675-A (GB)
Title: Improvements in or relating to the grinding or lapping of gears
IPC: B23F19/04
Filed: 1930-07-15
Abstract: 353,675. Lapping toothed gears. DETROIT & SECURITY TRUST CO., Detroit, Michigan, U.S.A.-(Assignees of Page, A. C. ; Detroit, Michigan, U.S.A.) July 15, 1930, No. 21347. Convention date, Sept. 25, 1929. [Class 60.] Gauges; spindles and spindle mountings.-In a machine for lapping an internal or external gear the gear and lap are relatively reciprocated in an axial direction and indexed while out of engagement, the gear and lap being rigidly held against rotary movements which would vary their intermeshing relationship during operation and one of them being held yieldably against lateral movement relative to the other. The lap is mounted on a table 3 in alignment with a vertical spindle 5 carrying the arbor of the gear blank. The table is supported on a receptacle 6 having a flange 9 which rests on the framing 2 and is surrounded by a perforated trough 11. The table is fitted with a worm gear 15 which is engaged by a worm 19 operated by a hand-wheel 23 for angular setting of the table. An annular recess 24 at the top of the table is adapted to receive a detachable ring 25 which is secured by bolts 27 and which supports a rib 29 provided on the lap 28, the lap being secured to the ring by bolts 31. The lap and ring are readily interchangeable for treating gears of different sizes. During operation lapping fluid such as kerosene mixed with abrasive is pumped into a funnel 43 mounted above the lap by means of a pump 33 driven by an electric motor 34 and delivering through a tap 40. The fluid passes into the receptacle 6 and is conveyed back to the pump by a pipe 42. The funnel 43 is in two sections, the lower section being changed when a lap of a different diameter is fitted. The gear blank is detachably mounted on a sleeve 47 which is secured to the spindle 5 by a screw cap 50. This sleeve has an extension 52 carrying a V-shaped saddle 53 which receives a gear arbor 59, the latter having a pin 60 fitting in a socket in the saddle. An arched clamping bar 54, Fig. 10, fitted with a latching lever 56 secures the arbor against the saddle and a spring-pressed pin 58 in the clamping-bar engages the side of the arbor but permits a limited amount of lateral movement of the gear arbor relatively to the lap. In some cases the gear may be slightly eccentric to the lap to increase the lapping action on the tops of the teeth. The spindle 5 is rotatable in a sleeve 68 which is splined to the housing at 69, the sleeve being reciprocated by a gear segment 72 which is pivoted at 11. Ball thrust bearings are provided at 74, 75. The spindle 5 has its upper end secured to a detachable spline extension 80 passing through a corresponding spline guide 83 which is bolted to a member 85 having a sleeve portion 86 carrying a gear 138. The spline extension and guide are readily detachable. In the case of helical gears the extension and guide have helical ribs of the same inclination as the gear to be cut so that the gear is automatically guided through the lap by means other than the lap itself. The machine is driven from a pulley 88 on a shaft 89 which carries a gear 91 which is connected to the shaft through an adjustable friction clutch member 93. The gear 91 engages a gear 97 mounted on a sleeve which is connected to a shaft 99 through a clutch band 102 operated by a wedge carried by a shiftable clutch member 106 actuated by a lever 107. The shaft 99 carries a crank pin 108 which through a rod 109 actuates the segment 72 to reciprocate the blank-spindle. In order to ensure that the machine is always stopped when the gear blank is in its upper position clear of the lap the clutch 106 can only be disengaged when a roller 112 is opposite a recess in a sleeve 106a secured to the clutch member. When the clutch is disengaged, the parts are brought quickly to rest by the engagement of the clutch member with a stationary braking surface 116. The weight of the work-spindle is partially counterbalanced by a spring 117. Indexing of the blank at each reciprocation is effected by means of a worm 123 on the spindle 99, the threads of which have circular portions 124 connected by helical portions 125, Fig. 7. This worm engages a worm wheel 126 which also has composite straight and helical teeth, the worm wheel being rotated through one pitch for each revolution of the worm. The worm wheel is connected through change gears 132 and gears 137, 138 to the blank spindle, and the indexing movement is timed to occur when the blank is clear of the lap. The blank spindle 5 is held against any angular movement which might be allowed by backlash in the indexing train by means of a split clamp 139 engaging the spline guide 83 and operated by a lever 143 to tighten the clamp. This lever is operated through a spring connection 146 and rods 148, 149 from a cam on the shaft 99 which is arranged to release the clamping action to a sufficient extent to permit the indexing movement at the required time. To determine the adjustment of the spring which gives the required load on the indexing train a scriber 156 is arranged to make a series of marks on the spline guide after each indexing movement while the machine is rotated by hand. The machine is then run under power and the spring is adjusted until the marks so made coincide with the scriber point after each indexing movement. The clutch lever 107 is pivoted to a rack bar 162 which is urged into disengaging position by a spring 163. The rack bar engages a pinion 166 actuated by a vertical rod 170 operated by a hand-lever 173. After operation of the rack bar the clutch is held in position by latch levers 175 having arms 177 which engage recesses, Fig. 15, in the rack bar. The latch levers may be released manually by operation of a rod 184, Fig. 14. In order to stop the machine after a predetermined number of operations the latch mechanism is tripped automatically by pins 188, 189 mounted on a worm wheel 186 driven through a gear train and clutch mechanism from the shaft 89. The clutch of this mechanism is interconnected with the main crank shaft clutch so that the worm gear 186 is automatically stopped when the main clutch is disengaged. In order to position successive gears so that the teeth bear the same relation to the pin 60 as the arbor a work-setting device is mounted on a bench 213 at the side of the machine. This comprises a notched web 215 having a socket to receive the pin 60 on the arbor and coacting with a clamping arm 216. A pivoted arm 219 carries a gear 221 similar to the gear 64 to be lapped the two gears being engaged by movement of the arm 219. In operation the first of a series of similar gears is positioned in the machine and the lap table is adjusted until the lap teeth engage correctly with the gear. The gear arbor is then placed on the setting device and the gear 221 adjusted manually until its teeth mesh with the gear on the arbor. Subsequent blanks are then mounted in correct relation to the setting gear 221. In some cases the gear blank may be mounted on the table and the lap on the reciprocating spindle. Specifications 279,597 and 282,152, [both in Class 60, Grinding or abrading &c.], are referred to.