Patent GB-749901-A (GB)
Title: Improvements in or relating to the generation of bevel gear tooth flank profiles
Inventor: DEAKIN THOMAS MEYRICK
IPC: B23F1/08
Filed: 1951-08-27
Abstract: 749,901. Gauging toothed gears. DEAKIN GEARS, Ltd. Nov. 27, 1952 [Aug. 27, 1951], No. 20200/51. Class 106 (2). [Also in Group XXII] A machine for generating or measuring the tooth flank profiles of a bevel gear and in which there is a relative generating roll motion between a workpiece 73 and a tool 11, comprises a master head 6 embodying an element 32 which, when oscillated, will produce-an oscillation of a further element 52 such that the relationship between the oscillations will be the same as the relationship between the first and second component rotary motions of the generating roll, means for separately transmitting said oscillatory motions to at least one other location, and a slave head 7 at each such location to combine vectorially the oscillatory motions. In a machine for broaching bevel gears, four slave head units 7 and a master head unit 6 are supported on a frame 4, 5 from pivots 3, 3a. Broaching heads 11 are mounted on slides on a back plate 8 and carry four broaches each of which is adapted to cut one tooth flank, as described in Specification 749,902. The master head unit 6 produces the two rotary components of a generating motion, namely the first rotary component motion of the cone about its own axis and the second rotary component motion of the axis of the generating cone about the vertical axis passing through the generating plane. These components are transmitted to, and recombined in, the slave heads. The master unit comprises a head 17 formed with a hollow shaft 16, the axis of which passes through the axis 3-3a. The head 17 carries, at each side, cheeks 18 formed with guideways 19 in which can be adjusted a frame 20, 21, 22 carrying a shaft 23 whose axis always intersects the axes 3-3a and that of the shaft 16. The head 17 also supports a rectilinear slide 26 having extensions 29a each formed with guideways 30 in which a horizontally disposed bar 34 is adjustable. The bar 34 carries tapes engaging a rolling disc 32 on the shaft 23. A further set of tapes is carried by the slide 26 on an edge 28 to engage a normally-stationary disc 36 journalled on the shaft 16. Movement of the head 17 therefore causes rolling movements of the tape mechanisms which represent the rolling of a cone 38 on a surface 39. The first component motion is that of the disc 32 which motion is transmitted, through a gear 43, gears 51, 50 on an arcuately adjustable block 47 and a gear 44, to a disc 52 on a shaft 45. The disc 52 transmits its motion by tapes to a slide 54 extending along the machine. A similar slide 42 transmits the second component from the motion of the shaft 16 through a disc 40. The shaft 16 is oscillated by a hydraulically-reciprocated rack and a pinion 55. A slave head unit 7, Fig. 7, for recombining the component motions is mounted on a slide 59 and carries a workpiece 73. The motions are communicated by the slides 54, 42 to discs 86, 83, similar to the discs 52, 40, through adjustable blocks 87, 84. When the slide 59 is moved to disengage the work from the tools the blocks 84, 87 are disengaged from the bars 42, 54. They are re-engaged on the return movement by spring-pressed keys 93, 94. Work-indexing.-To index the work there is provided on the disc 86 a radially movable dog 105 spring-urged towards the axis of the shaft 76 and adapted to engage one of a number of recesses 108 in an indexing-disc 109 on the shaft 76, the recesses being equal in number to the teeth to be cut. When the disc 86 is rotated, a roller 110 on the dog 105 runs up a pivoted lever 111, over a rail 113, and this is withdrawn down into a succeeding notch 108, the disc 109 being held stationary by a dog 121 drawn into a notch 108 by a second rail 116 as the roller runs below it and presses it outwardly. The rails 113 and 116 and the dog 121 are carried on a plate 103 mounted on bolts 90. The frame may be adjusted angularly by screw means for machining the dedendum of octoid bevel gears. According to the adjustment of the machine, spherical involute or octoid gears may be cut. The machine may run continuously, blanks being loaded and unloaded in succession. It is stated that the generating motion may be applied in part to the tool and that the machine may be used for gauging teeth by measuring the displacement of a feeler or by measuring the change in capacity between a feeler and a tooth. In the Provisional Specification it is stated that the heads may be arranged in a circle instead of in line, and that the transmission between the heads may be by an electrical servo-system. Specifications 689,192 and 718,101 also are referred to.