March 23, 1954 M. B. MENTLEY ET AL 2,672,716 LEAD FORMING OR CHECKING FIXTURE Filed Jan. 21, 1952 At HH a st - 1121. 54 5O INVENTORS y FIG.2. MAX B. MENT LEY ' A t E. E. 2 2. 2464 tons Patented Mar. 23, 1954 2,672,716 UNITED STATES PATENT OFFICE 2,672,716 LEAD FORMING OR CHECKING FIXTURE Max B. Mentley and John J. Sigman, Detroit, Mich., assignors to National Broach & Machine MichiganCompany, Detroit, Mich., a corporation of Application January 21, 1952, Serial No. 267,396 Claims. (C. 51-232) The present invention relates to a lead form 2 ing or checking fixture. ly opposite side of said element may contact the . The present invention is designed to produce sine bar to produce clockwise or counterclockwise uniform rotational motion of a member in re rotation of the member upon translation of the Sponse to or in accordance with uniform axial first slide in the same direction. movement of the member and accordingly, the 5 It is a further feature of the present invention mechanism may be employed either to generate to provide as a new article of main facture for lead on a member when employed in conjunction use in mechanism of the character described, an With a metal working tool such for example as involute acorn which is of circular cross-section a grinding wheel, or the mechanism may be in planes perpendicular to its axis and which associated with suitable checking instruments, in ) has side surfaces which are of identical involute Which case it will be useful to check the lead in any axial plane. or helix angle of a helicoidal surface. Other objects and features of the invention will It is an object of the present invention to pro become apparent as the description proceeds, vide simplified mechanism based upon sound especially when taken in conjunction with the ac geometric principles designed to generate a true companying drawings, wherein: lead. Figure 1 is a fragmentary plan view of the It is a further object of the present invention nechanism including the lead forming or check to provide mechanism for generating true lead, ing fixture. useful in either a metal working or checking de Figure 2 is an end elevation of the mechanism vice which employs an element having an in illustrated in Figure 1, with parts in Section. volute surface thereon carried by the rotatable Figure 3 is a diagrammatic view illustrating member and acting in conjunction with a sine the geometrical principle involved. bar. Figure 4 is a fragmentary elevational view of More Specifically, it is an object of the present a modified form of involute element and Sine invention to provide mechanism designed to pro 5 bar. duce uniform rotational motion in accordance Figure 5 is a section on the line 5-5, Fig With axial movement of a member by produc ure 4. ing relative motion between a sine bar located Referring now to Figure 1, the mechanism con in a plane perpendicular to the axis of the men prises a base 3 having rectilinear ways f2 in ber and an actuating arm secured to the mem Which a slide 4 is mounted for rectilinear motion. ber having an involute surface in contact with The slide f4 carries head and tailstocks indicated the sine bar. generally at 6 which include rotary Spindles 3 It is a feature of the present invention to pro adapted to support a rotary member 28. AS vide mechanism comprising a support, a first slide illustrated herein, the rotary member 2 carries nowable rectilinearly on the support, a member 5 a gear 22. It will be appreciated that where the mounted on the first slide for rotation about a mechanism illustrated herein is used as a grind fixed axis parallel to the direction of motion ing fixture, suitable index raechanism will be of the first slide, a second slide mounted on the provided to permit indexing of the gear 22. first slide for rectilinear motion thereon in a Mounted on the rotary member 2 is an airin direction perpendicular to the axis of said mem f) 24. Which as herein illustrated includes a sleeve ber, Sine bar mechanism for effecting uniform 26 by means of which the airn 24 may be clamped movement of Said Second slide in accordance With to the member 20. uniform movement of said first slide, an element Mounted on the side 4 is a plate 23 having rigidly carried by said member having an involute ways 33 formed therein which extend perpendic Surface thereon, the origin of which is spaced 45 ular to the axis of tile rota:'y member 2). from the axis of said member by a distance equal Rounted in the ways 3 for rectilineair innovenent to half the diameter of the base circle of the therein is a second slide 32. The slide 32 is pro involute, and a sine bar carried by said second vided with an adjustable sine bar 33 herein illus Silde having its surface in contact, with the strated as pivoted to the Second slide 32 about involute Surface of said element. an axis indicated at 36 and having an adjusting It is a further feature of the present inven turnbuckle device indicated generally at 33. By tion to provide mechanism of the character de operation of the turnbuckle device 38 the angular Scribed in which said element is in the form of ityquired. of the sine bar 34 may be adjusted as re an involute acorn of circular transverse cross Section and having side surfaces which are in 5 5 The airn 28 at its Outer end is provided with an volute in any axial plane, and means for hiasing element 40 which includes an involute side sur the involute element into contact with its asso face in slidable contact with the adjacent Sur ciated sine bar, said biasing means being re face of the sine bar 34. Preferably, the element AG is in the form of an acorn which is of circular versible SO that either one side or the diametrical () Cross-section in any plane perpendicular to its 2,672,716 As 3. w the same time uniform rotation is imparted to axis and having its side surfaces of the same in the-rotary member 20 dependent upon the angul volute form in any axial plane. The element 40 larity of the sine. bar:34. Moreover, it will be either with, or without its supporting arm 24, is apparent that the direction of rotation of the Considered to be a new and useful article of manu member 20 resulting from movement of the lower facture. The element 40 may be mounted fol: slide 4 in a given direction will be dependent rotation about its axis relative to the arm 24 upon: whether; the involute acorn 49 is in the Whereby the involute Surface thereof in...contact. full line or... the dotted line position shown in with the sine bar 34 may be varied at will. Thus, Figure, 2. after a period of use the element 40 may bead The mechanism. So far described may be used justed to bring new elements of its surface.into. 0: in conjunction. With a machine for producing Coaction. With the Sine bar. helicoidal surfaces. Thus, in Figure 2 there is in The base 0 includes a supporting portion 42 dicated in dottedlines a grinding wheel 74, the Sur which is stationary with respect thereto, Mount. faces of which as indicated at 76 may be trinned ed on the Support portion 42 is a second:sine bar; to involute shape. It will be understood that 44 which is mounted for angular adjustment 5 When the mechanism is employed in a glinder, the about a pivot axis indicated at 46 and which grinding wheel T4 in use will be rotated about the includes suitable mechanism, herein illustrated as axis of a supporting shaft. T8 and will be main a turnbuckle 48, for effecting angular adjust tained in space while the slide f4 is reversed. ment of the sine bal'A4. The slide 32 includes a Since uniform traverse of the slide 4, as pre projection 5 provided with a roller 52 adapted to 2 viously described in detail, results in uniform ros engage the sine bar 44. tational movement of the member 20, this uniform Secured to the plate 28 is a bracket 54-which in rotational movement"will be impacted to the gear cludes an upwardly extending portion 56 carrying 22 and accordingly, the grinder may be used to a. transversely extending strap 58. Intermediate grind involute helicoidal Surfaces on the gear. the strap, 58 and the adjacent end of the upper : Where the mechanism is employed for grinding slide 32 area, plurality of tension springs 69 which gear teeth indexing mechanism will be provided bias the upper slide 32 to the right to maintain intermediate the rotary member 20 and the gear the roller 52 in contact. With the Sine bar 44. 22 to permit shifting of the gear 22"relative...to Secured, to the rotary member 20 is an arm 62 the rotary member 20' to grind all of the teeth the outer end of which is connected to a ten 30 Successively. sion spring 64 which may be connected to a post The same mechanism may be employed to check 66 or a post 68 to apply accounterclockwise bias the accuracy of previously produced, helicoidal ing force to the member 20. Thus, when the surfaces by mounting an indicator of conventional spring 64 connects the arm 62 to the post 66 it type in such position that the ball contact thereof biases the rotary member 29 in a counterclock engages a helicoidal surface on the Workpiece.