Patent GB-488957-A (GB)
Title: Rolling device, employing base circle or disc and straight line rolling or swinging thereon without slip, particularly for machine tools
IPC: B23F5/20
Filed: 1937-02-03
Abstract: 488,957. Trueing grinding - wheels. ZAHNRADFABRIK FRIEDRICHSHAFEN AKT.-GES. Feb. 3, 1937, No. 3249. Convention date, Feb. 17, 1936. [Class 60] [Also in Group XXII] A rolling-generating mechanism particularly for forming involute gears or trueing involute surfaces of grinding-wheels or the like has part of the mechanism guided in a circular or straight line path which approximates to an " extended " or an " abridged " involute. In Fig. 1, the involute 3 is formed by a point C1. on a line 1 rolling on a circle 2 while an extended involute 4 is formed by a point A1 coupled to the rolling line 1 and moving from A1 to B1 while the line 1 moves from its starting position to the dotted line position. Between the points A1 and B1 the extended involute closely approximates to an arc of a circle of radius R1. Similarly in Fig. 3, a point A3 connected to and lying on the opposite side of the rolling line 31 producing the involute 33 describes an abridged involute 34 of which the portion A3, B3 closely approximates to a circular arc of radius R3. Other portions of the modified involutes will approximate to arcuate curves having different centres. In another case, Fig. 4, the extended involute A4 closely approximates, between the limits A4, 134 to a straight line G. In a modification for trueing up an involute surface on a grinding- wheel 58, Fig. 5, a diamond tool 50 lies in the imaginary rolling line and is connected to a member 55 of which the upper end is guided over an approximate extended involute by means of a link 54 while the lower end is sinmltaneously guided over an approximate abridged involute by means of a link 56. Thus when the system is displaced about the fixed member 57 the tool describes an involute 53. In another modification, Fig. 6, the upper end of the tool holder 65 is guided along an approximate extended involute by a link 64 while the imaginary line 61 is constrained to roll on the circle 62 by means of a guide surface 65<1> moving over a circular member 69. In another modification, Fig. 8, a toothed pinion P mounted on a spindle M is constrained to rotate by means of a link 84 while the carrier of the spindle M moves along a straight line 89 approximating to an extended involute. The pinion may thus be given a correct rolling movement past a stationary grinding-wheel 88 to grind the involute tooth surfaces. In a modification of this form a uniform rotary movement may be imparted to a rotary member by means of a slide guided on a straight line path approximating to an extended or abridged involute. In a further modification, Fig. 10, means are provided for maintaining a trimming tool 100 at right-angles to the work such as a profiled grinding-disc. A stationary templet 107 is connected by link 104 to a bearing A10 guided in an arcuate path corresponding to an upper involute of base circle 102. The bearing A10 is connected to the tool holding arm which is guided on the templet 107. In another modification the arcuate guide may approximate to an abridged involute of the circle 102. The templet may be replaced by flexible band or other mechanism for guiding the trimming tool in an involute path.