US2432335A

US2432335A - Involute form dresser for grinding wheels

Info

Publication number: US2432335A
Application number: US522219A
Authority: US
Inventors: Peters Carl
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-02-14
Filing date: 1944-02-14
Publication date: 1947-12-09
Anticipated expiration: 1964-12-09

Description

Dec. 9, 1947. c. lPETERS INVOLUTE FORM DRESSER FOR GRINDING WHEELS Filed Feb.n 14, 1944 2 Sheets-,Sheet 1 t4/ll mpaug@ (Ittomegs Dec. 9, 1947. C, PETERS 2,432,335

INVOLUTE FORM DRESSER FOR `GRINDING WEELS Filed- Feb. 14, 1944 2 Sheets-Sheet 2 l 4 Gttornegs Patented Dec. 9, 1947 UNITED STATES PATENT OFFICE lNvoLU'rE FORM DREssER Fon dmNpINcr WHEELS Carl Peters, Dearborn, Mich.

Application February 14, 1944, Serial No. 522,219

(Cl. 12S-11) 19 Claims. l

The present invention relates to grinding wheel dressers, and more particularly, to a dresser for imparting an involute form to the periphery of the grinding wheel.

The primary object of the invention `is to provide a grinding wheel dresser having the various parts thereof so correlated as to cause the dressing tool to traverse a true involute curve and thereby generate a grinding wheel surface having a corresponding involute peripheral surface.

Another object of the invention is to provide an involute dresser for grinding wheels in which the 4dresser may be reversed 'so that both sides of the wheel adjacent the periphery thereof may be cut to form and generate an involute curved surface without requiring extensive measurements and compilations with respect to the two positions of operation.

Another object of the invention is to provide an involute form dresser for surfacing the peripheral edge lof grinding wheels in which the `dresser is supported between a pair ,of opposed axially aligned `centers to maintain la true relationship with respect to the grinding wheel. Another object of the invention is to provide an involute form dresser for grinding wheels in which the dresser is supported between a pair of `opposed axially aligned centers to maintain a true relationship with respect to the grinding wheel.

Another `object of the invention is lto provide an involute form dresser 4for grinding wheels in which the dressing tool may be adjusted to various positions so as to permit the dressing tool to be used for forming involute curve surfaces for various diameter gears without requiring the alteration of the dressing tool except for a minor adjustment to the cutting tool thereof.

Another object of the invention is to `provide an involute form dresser which may be supported between the centers of a grinding machine so ras to position the cutting t-ool directly beneath the periphery of the `grinding wheel, thereby ,aiding Vin maintaining a direct relationship between ,the involute form `dresser and a ixed reference point.

Another object of the invention is to provide an involute form dresser of the above-mentioned character which may be quickly and easily adjusted so as to enable the involute dresser to be used in dressing grinding wheels with a large number of involute forms depending upon the diameter of the gear and the required involute tooth form.

Another object .of the invention is to provide Aan involute form dresser'for grinding wheels in which all of the parts are so tted and correlated as to provide a dresser which will inscribe an ,involute forni with a high degree yof accuracy .and precision,

Other .Objects and advantages Will become epparent during the course of the following description of the accompanying drawings, wherein:

Figure .l is a .top plan View of the inveluie form dresser illustrating portions thereof broken away to show various vdetails of construction and the arrangement of parts;

Figure?I is an end elevational View of an involute form dresser illustrating the same in its normal position presented directly beneath a grinding wheel to be' Qrmed;

Figure 3 is .a vertical cross ,sectorial View taken on the zigzag line {1H- 3 of Figure 1 looking in the direction of the arrows and ,illustrating the manner in which the dresser is rotated to inscribe an involute curve and provide a corresponding contour surface on the periphery of the 'grinding Wheel: y

Figure 4 is a vertical cross sectional view taken o n the irregular line 4-4 in `Figure 2 looking in the direction of the arrows, illustrating the various Vstructural details of the involute form dresser Vand the arrangement and relation thereof between the centers `of a grinding machine;

Figure 5 4isa diagrammatic view of the dressing cutter illustrating the manner in which the same is moved along an involute curve to generate a corresponding contour` surface on the periphery of the grinding wheel;

Figure 6` is an enlarged fragmentary side elevational View showing the various structural details of the slide supporting brackets; and

Figure is a cross`sectional View taken on the diagonal line A"l---'l in Figure 3'looking in the direction of the arrows and illustrating in detail the pivot connection between the adjustable sine bar and the movablerack member.`

In the drawing, Figures land 4 show a grinding machine having a rigid frame 4, a portion only being shown. Mounted upon the machine frame 4 are conventional opposing center supports 5 and 6. The center supports 5 and 6 are provided with the usual centers jl and 8 and are shown in Figures `2, f3 and l directly beneath a grinding wheel G. The above structure is typical of a grinding machine having center supports for supporting work or the like and the grinding Wheel G is movable vertically with respect -to said supports so that the 4 grinding Wheel may be fed toward and away therefrom.

The invention comprises an involute form dresser generally designated by the reference character I0 and said involute form dresser comprises a casing structure generally indicated as Lat Il for being suppOrted between the centers l and 8 of the Aabove-mentioned grinding machine. The caslngstruture Il comprises aframe section including a front wall plate l2 having angular end portions 1 3 and `UL The end well portion I4 is slightly offset as at I5 and said angular end portions I3 and I4 are connected by a plate section I6 fastened in place at its ends by means of machine screws or the like as at I1. Projections I8 may be formed on the free edges of the angular end walls I3 and I4 so as to be received in rectangular notches I9 formed in the corners of the plate member I6 and thereby prevent relative'sliding movement between the casing section and the plate member I6.

Fitted on the center support and center 1 is a collar 29 adapted to be held in place by a set screw 2| and said collar is provided with a flat surface 22 under which a support or block as indicated in Figure 4 may be inserted as at 23, the block 23 being seated upon a rigid portion of the machine frame 4 so as to hold the center support and collar 20 against rotation and provide a substantially rigid and solid support. The collar 26 is provided with a reduced annular boss 24 for being received in an opening 26 in the plate member I6 and said plate member is positioned on said annular boss 24 in such a manner as to be rotatable thereon about the axis of the centers 'I and 8.

Formed integral with the front wall I2 of the frame section is a tubular extension 26 having a bore 21 adapted to receive a tubular extension 28 formed on the collar` 20. In assembling the parts, the tubular extension 26 is telescoped over the tubular extension 28 with the tubular extension 26 rotatably mounted on the tubular extension 28 so as to further increase the supporting surface for the involute form dresser and maintain the parts in their assembled relation.

Fitted on the tubular extension 28 is the hub portion 29 of a sector gear 30 and said hub portion is rigidly afxed to the collar 26 by means of machine screws or the like as at 3 I The heads of the machine screws are received in countersunk bores 32 so as to provide adequate clearance for the rotation of the tubular extension 26 on the tubular extension 28. Gear teeth 33 are formed on the sector gear 30 and it is to be noted that the sector gear 30 is held in a rigid position against rotation due to the fact that the same is bolted to the collar 20.

Slidably mounted relative to the frame section and between the sector gear 30 and angular end wall I4 is a rack bar 34 having rack rteeth 35 adapted to engage and mesh with rthe teeth 33 formed on the peripheral surface of the sector gear 3U. The back wall 35a, of the rack bar slidably engages the inner wall surface of the angular end wall I4 as shown clearly in Figures 1 and 3. Secured to the rack bar 34 along one side thereof is a supporting plate 31 adapted to be fastened in place by means of machine screws or the like 38 with their heads received in countersunk bores 39 in the rack bar 34 to permit free sliding movement of the rack bar against the plate member I6. The opposite ends of the machine screw 38 are received in screw-threaded openings 46 in the support plate 31 and said support plate is provided with an offset extension 4I intermediate its ends so that the free end may be bifurcated as at 42 to provide a pair of spaced arms 43. The arms 43 are provided with openings 44 in axial alignment for receiving a fulcrum pin 45 (Figure '1).

Mounted to oscillate on the fulcrum pin 45 and between the bifurcated arms 43 is a sine bar 46 having its corner portions`at its opposite ends notched as at 41 (Figure 3) to receive rounds 48. The rounds 48 are held in place by machine screws or the like as at 49, the heads of which are received in countersunk bores 50 extending through the top wall of the sine bar 46. The upper round 43 directly engages the front edge of the supporting plate 31 whereas the lower round 46 engages one end of a gauge block B tightly wedged and frictionally held between the supporting plate 31 and said lower round 43 so as to maintain the sine bar in a preset adjusted position. Different-sized sine blocks B may be employed depending on the predetermined angle desired.

Secured to the sine 4bar 46 and extending along the edge thereof is a slotted plate 5I having a longitudinal slot 52 extending from one end to the other and said slotted plate is provided with a central bracket portion 53 adapted to be fastened tothe sine bar 46 by means of spaced machine screws 54 with the heads thereof countersunk in suitable bores as indicated in Figure 7. The slotted plate 5I is placed in sliding contactual engagement with the front wall I2 of the casing section and one end thereof is received in the offset portion I5 of the end Wall I4 so as to permit the sine bar to be tilted to approximately 45 degrees as indicated in Figure 3. The outer surface of the tubular extension 26 is attened as at 55 to further permit the free swinging movement of the sine bar and the full travel of the slotted bar 5I to the limit of its angular movement.

Formed integral with the front wall I2 of the casing section is a pair of spaced

bracket arms

56 and 51 and said bracket arms are connected at their outer ends by an integrated bar 58. The undersides of the

bracket extensions

56 and 51 are cut away as at 60 and 6I t-o accommodate an angled slide bar 62 having its angular portion 63 received between the front wall I2 of the frame section and the cutaway portion of each of the

bracket arms

56 and 51. A guide rib 64 is secured to the front wall I2 of the casing section by means of suitable machine screws 65 having their heads received in suitable countersunk bores therein. The guide rib 64 is notched as at 66 to receive the upper edge of the angle portion 63 and hold the same in slidable engagement with the front wall I2 of the casing section. The other end of the angled slide bar 62 is guided between a pair of spaced guide members 61 secured to the undersides of the free ends of the

bracket extensions

56 and 51 by machine screws 66 received in countersunk bores therein (Figure 6) An additional guide plate or rib 69 is affixed to the llower portion of the front wall I2 and is similarly held in place by machine screws 16 extending therethrough with their heads received in countersunk bores (Figure 4). The guide rib 69 engages the underside of the angled slide bar 62 so as to hold the same against the guide rib 64 and within the notch 66.

Formed intermediate the ends of the angled slide bar 62 is a V-notch 1I and fastened beneath the angled slide bar 62 adjacent said notch is a clamping frame 12 having an opening 13 for receiving the lower end of a dressing tool support 'll-l so that the same may be held in clamping engagement with the V-notch 1I by means of a set screw 15 threaded in a bore in the clamping frame 'J2 as at 16 with the free end of the set screw engaging the peripheral surface of the dressing tool support 14. The dressing tool support 14 is tubular and is provided with a central longitudinal bore 11 terminating at the end in enlarged

bores

18 and 19. Received within the enlargel `here 19 is the shank portion `80 of Ian adapter having a head 8| and extendingthrough said bore 11 is a locking screw 82 having its head 83 received in said enlarged bore 18 and its threaded portion 84 received in a threaded bore 85 in thelshanlr r8l] of said adapter. The head portion 8| of the adapter is provided with a pair of diametrically disposed projections Sla adapted to be received in notches 88 formedin the upper end of the cutting tool support 14. The adapter 8l is provided with an offset arm 81 having a transverse bore for receiving a diamond cutting tool 88 which may be held in place by a set screw ,or the like as at 89. The diamond cutting tool B8 is held in said transverse bore 9i) by the set screw 89 so that the diamond cutting point thereof as at 9i `will project from the oifset arm 81 as shown in Figures 2, 3 and 5. Secured to the angle portion 63 of the slide 82 is a pin SZhaving its free end projecting through a slot 94 in the front wall casing section I2 in direct alignment with the slot 52 formed in the slotted plate 5l. The extreme free end of the pin 92 is received in an opening in a sliding block 95 mounted to move in the slot 52 of the slotted bar 5l from one end thereof to the other. provided with an opening 96 for the reception of said pin 92 so that relative sliding movement between the slotted bar and casing I will impart sliding movement to said block 95 and a corresponding sliding movement to the slide 62.

Formed intermediate the ends of the integrated bar 58 is a centering opening 95a having tapered Walls for receiving the conical ends of the center' 8 and said tapered opening 95a is in direct alignment with the axis of the collar 2i! and tubular extension 28. t will thus be seen that the frame casing iii may be supported between the centers ,1 and 8 of a suitable grinding machine so as to position the involute form dresser beneath the periphery of the grinding wheel.

' n operation it will be assumed that the involute form dresser is positioned between the centers of the grinding machines 1 and 8 as above described so that the cutting tool holder 14 will be directly beneath the grinding wheel G (Figures 2 to 5 incl). With the Wheel G in the position shown in Figure 4, and the sine bar i8 adjusted in the position shown in Figure 2, the casing frame section I0 may be rotated about the axis of the centers 1 and 8 from the position shown in Figure 2 to the position shown in Figure 3. Upon rotation of the `casing i@ the rack bar 3d tracks on the stationary sector gear 38 so as to cause a relative sliding movement between the casing I0 and the sine bar d6. This sliding movement is translated to the diamond point supporting member y'ill through the medium of the angled slide` bar t2, pin 92 and slotted bar 5i. It is noted that rotation of the casing i8 about the centers 1 and 8 in a clockwise direction causes the angled slide bar 62 to be moved to the left a proportionate distance so lthat the end of the diamond cutting tool 9i will inscribe an involute curve as indicated by the dotted line C in Figures 2 and 3. By moving the casing IE) to and fro on its axis so as to oscillate the casing thereon, the diamond point 9i will generate an involute curve starting from the base circle of the stationary gear and ending at a point determined by the limited rotation of the casing lil. As thecasing I8 is oscillated back and forth, the grinding wheel G is moved from the full line position shown in Figure i to the dotted line position so as to feed the grinding Wheel into the diamond point 9| and The slide block 8,5 is

thereby form an involute contour I `on the Aperiphery of the grinding wheel Cr. After one side of the peripheral edge of the grinding `wheel has thus been dressed, the bolt 82 is loosened so as to permit the offset arm 81 to be swung about an arc of `18() degrees to position the diamond cutting tool `9i on the other side of the wheel to inscribe the involute curve C. When the diamond cutting point `9i is thus reversed and the sine bar 46 similarly `reversed by inserting a gauge block under the other end thereof, the casing lll may be swung in a counterclockwise direction so as to form and dress the grinding wheel G with an involute contour I (Figure 5). When the grinding wheel G has been fed to a point in alignment with the base circle of the sector gear 30 and one side of the peripheral grinding wheel edge has thus been dressed, the grinding wheel is retracted and the .offset arm B1 shiftedso as to position the diamond point 9| on the other side of the wheel whereupon :the wheel is again fed as above described and the casing I0 oscillated in a counterclockwise direction.

In setting the sine bar to the desired angle it is necessary to take into consideration the size of the gear for which the grinding wheel is being ma-de or formed with contour surfaces to meet the requirements of the gear structure. As an example, let it be assumed that the gear is of a predetermined diameter which diameter is equal to or smaller than the pitch circle of the stationary Igear 38. By simply dividing the base circle circumference of the sector gear 30 by the base circle circumference of the gear being constructed, a fraction will be given which will equal the tangent or rate of change of speed which must be imparted to the diamond cutting point 9| when the casing is oscillated so as t0 give a prescribed involute `curve. Having thus found the tangent which controls the movement of the diamond point cutting tool 9i, the sine thereof may be easily found from a trigonometric table so that the sine bar 46 may be moved to a position to give the required acceleration to the diamond point cutting tool 9| by inserting a gauge block B of a `known length between the rounds i3 and the rack gear plate 1i. For instance, if the gear being considered has a base circle circumference equal to the base circle circumference of the sector gear 3i), by simple division the quotient 1 will be given which is the tangent of 45 degrees. Hence, it will be necessary to set the sine bar 46 at such an angle and to do this it is on,y necessary to select the corresponding sine from a table of trigonometric functions and insert a gauge or sine block B as shown in Figure 3. The opposite end of the sine block when thesine bar is in this position will have its rounds 138 engaging the edge of the rack bar plate 31.

It is to be noted that the tool support 14 may be raised or lowered so as to position the damond cutting tool v9i adistance from the axis of rotation of the casing I0 equal to the radius of the gear for which the grinding wheel G is being contoured and it is to be noted that when gears havins a smaller diameter than the base c.rc.e of the sector gear 30 are under consideration the diamond point tool supporting member 14 may be lowered within a considerable range within the radius of the stationary gear 30.

Actually, the motion imparted to the diamond point cutting tool 9| is a retrograde movement `in Vthe direction opposite to the rotation of the casing l0, That is, the diamond point cutting tool 9| is fed tangentially to increase the distance between the points of the diamond cutting tool and the axis of rotation of the casing a proportionate amount depending on the -angularity of involute contours I and I have been formed on the peripheral side edges of the grinding Wheel.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred embodiment of the same and that various changes may be made in the shape, size and arrangement of parts without departing from the spirit of the invention or the scope of the subjoined claims.

What I claim is:

1. An involute form dresser comprising support means, a frame member mounted to oscillate about a pivotal point on said support means, a stationary toothed member within said frame member aiiixed to said support means, a rack slidably mounted in said frame member in tracking engagement with said toothed member, a slide movably mounted on said frame member to move radially with respect to the pivotal axis thereof and in a plane perpendicular to the movement of said rack, a cutting and dressing tool support secured to said slide extending perpendicular thereto, and an actuator pivotally mounted on the rack having a sliding connection with said slide to cause the end of said tool support to inscribe an involute curve upon oscillation of said frame member.

2. An involute form dresser comprising support means, a frame member mounted to oscillate abouta pivotal point on said support means, a stationary toothed member within said frame member aixed to said support means, a rack slidably mounted in said frame member in tracking engagement with said toothed member, a slide movably mounted on said frame member to move radially with respect to the pivotal axis of said frame and in a plane perpendicular to the movement of said rack, a cutting and dressing tool support secured to said slide extending perpendicular therefrom, an adjustable bar member pivoted to the rack member, and a slidable connection between the bar member and slide to cause the end of said tool support .to travel along an involute curve when said frame member is oscillated about its pivotal axis.

3. An involute form dresser comprising support means, a frame member mounted to oscillate about a pivotal point on said support means, a stationary toothed member within said frame member affixed to said support means, a rack slidably mounted in said frame member in tracking engagement with said toothed member, a

Vslide movably mounted on said frame member to move radially with respect to the pivotal axis of said frame and in a plane perpendicular to the movement of said rack, a cutting and dressing tool support secured to said slide, a sine bar piving engagement with said toothed member, a slide movably mounted on said frame member to move radially lwith respect to the axis of said frame and in a plane perpendicular to the movement of said rack, a cutting and dressing tool support secured to said slide, and an actuator pivotally mounted on the rack having a sliding connection with said slide to cause the end of said tool support to inscribe an involute curve, said tool support being provided with a diamond cutting tool adapted to be radially presented to the center line and peripheral edge of a grinding wheel to cut a surface on both sides of said center line conforming in cross section to the contour of said curve when said frame is oscillated about its pivotal axis.

5. An involute form dresser comprising support means, a frame member mounted to oscillate about a pivotal point on said support means, a stationary toothed member wit-hin said frame member affixed to said support means, a rack slidably mounted in said frame member in tracking engagement with said toothed member, a slide movably mounted on said frame member to move radially with respect to the axis of said frame and in a plane perpendicular to the movement of said rack, a cutting and dressing tool support secured to said slide extending perpendicular to the slide, and an actuator pivotally mounted on the rack having a sliding connection with said slide to cause the end of said tool support to inscribe an involute curve, said cutting and dressing tool support being adjustable relative to said slide and arranged on the center line of a grinding wheel for movement on either side thereof upon oscillation of said frame member about its pivotal axis.

6. An involute form dresser comprising support means, a frame member mounted to oicillate about a pivotal axis on said support means, a stationary toothed member within said frame member afiixed to said support means, a rack slidably mounted in said frame member in tracking engagement with said toothed member, a slide movably mounted on said frame member to move radially with respect to said axis in a plane perpendicular to the movement of said rack, a cutting and dressing tool support secured to said slide extending perpendicular thereto, and an actuator pivotally mounted on the rack having a sliding connection with said slide to cause the end of said tool support to inscribe an involute curve when said frame is oscillated about its axis, said cutting tool support being mounted on the slide to permit the longitudinal adjustment thereof in a direction perpendicular to the direction of movement of said slide and said slide actuator being provided with a surface for being engaged by a gauge block interposed between the actuator and rack.

7. An involute form dresser comprising support means, a frame member mounted to oscillate about a pivotal point on said support means, a stationary toothed member within said frame member aixed to said support means, a rack slidably mounted in said frame member in tracking engagement with said toothed member, a slide movably mounted on said frame member to move in a plane perpendicular to lthe movement of said rack, a cutting and dressing tool support secured to said slide, and an actuator pivotally mounted on the rack having a sliding connection with said slide to cause the end of said tool support to inscribe an involute curve, said actuator being provided with a surface at each end thereof for being engaged by a: gaugeblock.'- interposed` between the` rack and said actuator.

8. An involute form dresser comprising support. means, a frame' member mounted to. oscillate about' a pivotal point. onsaid support means, a Stationary toothed member within said frame member afxed to said support means, a rack slidably mounted' in said framemember in tracking engagement withl said toothed member, a slide movably mounted on said' frame member to move radially with respect to the axis of said' frame and in a plane perpendicular to the movement oi said rack, a cutting and dressing tool support secured to saidr slide and extending perpendicular thereto so as to be arranged for movement on either side of the center line of a grinding wheel, and an actuator pivotally mounted on the rack having a sliding connection with said slide to cause the end of said tool support to inscribel an involute curve on either side of said center line when said framer is oscillated about its pivot point, said actuator being offset from said rack to permit adjustment thereof to various angles whereby the tool support will be moved at various rates of speed to inscribe involute arcs of different pitch.

9. An involute form dresser comprising support means, a frame member mounted to oscillate about a pivotal pointA on said support means, a stationary toothed member within said frame member aixed tosaid support means, a rack slidably mounted in said frame member in tracking engagement with said toothed member, a slide movably mounted on said frame member to move in a plane perpendicular to the movement of said rack, a cutting and dressing tool support secured to said slide, an adjustable bary member pivoted to the rack member, and a slidable connection between the bar member and slide to cause the end of said tool support to travel along an involute curve when said frame' member is osciliated about its pivotal axis, said adjustable bar member being pivoted between its ends with gauge block engaging members' disposed at each end thereof for being engaged by a gauge block inserted between the rack member and said bar to hold said bar in a predeterminedl position,

10. An involute form dresser4 comprising support means, a irame member mounted to oscillate about a pivotal point on said support mea-ns, a stationary toothed member within said frame member afxed to said support means, a rack slidably mounted in said frame member in tracking engagement with said toothed member, al slide movably mounted on said frame member to move in a plane perpendicular to the movement of said rack, a cutting and dressing tool support secured to said slide, a sine bar pivoted to the rack member, and a sliding connectiony between the slide and sine bar whereby oscillation of said frame member about its axis will cause the end of said tool sup-port to traverse an involute curve, said sine bar being pivoted to the rack intermediate its ends to permit the insertion of a gauge block between the free ends of the sine bar and said rack whereby said sine bar may beheld in a predetermined adjusted position.

11. An involute form dresser` adapted to be supported on a grinding. machine having a grinding wheel and opposed spaced support centers disposed therebeneath, comprising a frame member mounted between said centers for oscillation about the axis thereof, a grinding wheel dressing tool mounted on said frame member and disposed for movement along an involute path on 10 either side oi"A the center line of said` grinding, wheel upon oscillation of said' frame member about its axis, means to.` move said dressing tool over the' peripheral edge of the grinding wheel to` generate an involute contour thereon, and means' for adjustingv said last-named means to cause said dressing tool totravel in a number of'Y involute arcs of different pitch, said adjusting means comprisingA a sine bar which may be adjusted to impart` the desired ratev of travel ofV said dressing tool.

12. An involute form dresser for ai grinding machine having a grinding Wheel and opposed spaced support centersl disposed therebeneath, support meansA disposed between said centers, a frame mounted on said support means for oscillation about the axis of' said centers, a grinding wheel dressing toolmounted on said frame members presented to the' peripheral edge of the grinding wheel and-arranged for movement along an involute path onf either side of the center line of said grinding wheel, meansI to move` said dressing tool over the peripheral edge of the grinding wheel on one side of said center line to generate an involute contour thereon, means for adjusting said last-named means to cause said dressing tool to travel in a numberl of involute arcs of diiierent` pitch, andl means to reverse the position of said grinding wheel dressing tool to a location on the other side of said center lineto cause the tool to traverse the other peripheral edge of said grinding wheel and dress an involute contour thereon.

13. An involute form dresser for a grinding machine having a grinding wheel and opposed spaced support centers disposed therebeneath, compris'- ing a tubularv support member mounted on one of said spaced centers iixed against rotation, a casing frame mounted on said tubular supportand engaging the other spaced' support center to rotate about the common axis of said centers, a toothedv gear member within said frame axed to said tubular support member, a rack slidably mounted in said frame in rocking engagement -Y with said toothed member, a slide carriedv by said frame movable radially with respect to the said axis, a grinding wheel dressing tool' support mounted on the slide and arranged to position a dressing tool beneath the peripheral edge of the grinding wheel forV movement along an involute pathway on either side of the center line of said grinding wheel, a sine bar pivoted to the rack, and a slidable connection between the slide and sine bar to cause said dressing tool to move over ithe peripheral edge of the grinding wheel on either side of the center line thereof and inscribe an involute form thereon whenlsaid-` casingl frame is oscillated about its axis.

14s. An involute con-tour dresser for aggrinding machine having a' grinding wheel and opposed spaced support centers disposed therebeneath, comprising a tubular support member mounted on one of said spaced centers xed against rotation, a casing frame mounted on said tubular' support and engaging the other spaced support center to rotate about the common axis of said centers, a toothed gear member within said frame aflixed to said tubular support member, a rack slidably mounted in said frame in rocking engagement with said toothed member, a slide carried by said frame formovement radially with respect to said axis, a grindingwheel dressing tool support mounted on the slide arranged to position a dressing tool beneath the peripheral edge of the grinding wheel for movement along an involute pathway on either side of the center line of said grinding wheel, and a sine bar pivoted to the rack intermediate its ends having aslotfor being engaged bya'projection on said slide whereby rocking movement of'said frame in one of its two rotational directions will cause said dressing tool to generate an involute curve and dress said grinding wheel with a corresponding contour on one side of said center line corresponding to the predetermined position of the dressing tool.

15. An involute form dresser for -grinding wheels, comprising a support, a frame member oscillatable about a pivot point on said support, a dressing tool slidably carried by said frame member and arranged on the center line of said grinding wheel for movement along an involute pathway on either side of said center line, a sectorshaped member secured to said support, a movable bar member drivingly engaging said sectorshaped member, a sine bar pivoted to said bar member, and a sliding connection between said sine bar and said dressing tool to cause said tool to inscribe an involute contour on one side of the center line of the grinding wheel surface as the frame member is oscillated about its pivot point in one Vof its two directions of rotational movement and to move said dressing' tool to inscribe an inn volute contour on the other side of said center line of the grinding wheel when said frame member is rotated in its other Adirection of rotational movement.

16. An involute form dresser for grinding Wheels, comprising a support, a frame member oscillatableV about a pivot point on said support, a dressing tool slidably carried by said frame member and arranged in a position for movement along an involute pathway on either side of the center lineof said grinding wheel, a sector-shaped member secured to said support, a movable bar member kdrivingly Vengaging said sector-shaped member,a sine bar pivoted to said bar member, and a sliding connection between said sine bar and said dressing tool to cause said toolto inscribe an involute contour on one side of the center line of the grinding wheel surface as the frame-member is rotated about its pivot point in one of its two directions' ofrotation and to inscribe an involute contour on the other side of the center line of the grinding wheel when said frame member is rotated in its other direction of rotational movement, said sliding connection being adjustable to impart a movement to said tool proportionate to the amount of rotation imparted to the frame member to accommodate involute forms of various pitch. i

17. An involute form dresser for grinding wheels, comprising a support, a frame member oscillatable about a pivot point on said support, a dressing tool support slidably carried by said frame member and arranged for movement along an involute pathway on either side of the centerline of said grinding wheel, a sector-shaped member secured to said support, a movable bar member drivingly engaging said sector-shaped member, a grinding wheel surface dressing tool reversibly positioned on said support movable to oppositesides of said center line, and a sliding connection between said bar member and said dressing tool to cause said tool to inscribe an involute contouren both sides of thegcenterline of said grinding Wheel surface when the dressing tool is shifted from one side thereof to the other and as the frame member is oscillated about its pivot point, said sliding connection comprising a ysine bar pivoted tothe bar member capable of adjustment to various angles to impart a tangential movement to the dressing tool proportionate to the amount of rotation of the frame member whereby grinding wheels with involute forms of Various pitch may be dressed and said dressing tool being adjustable radially with respect to the pivot point of said frame member to permit the dressing of involute surfaces generated from various base circles. Y

18. An involute form dresser for grinding wheels, comprising a support, a'frame member oscillatab-le about a pivot point on said support, a dressing tool slidably carried by said frame member and arranged for movement along in involute pathway on either side of the center line of said grinding wheel, a sector-shaped member secured to said support, a movable bar member drivingly engaging said sector-shaped member, a sine bar pivoted to said bar member, a sliding connection between said sine bar and said dressing tool to cause said tool to inscribe an involute contour on one side of the centerline of the grinding wheel surface as the frame member is rotated about its pivot point in one direction of rotation and to Cause said dressing tool to' inscribe an involute contour on the other side of said centerline when said frame member is rotated in its other direction of rotational movement, and a keeper member adapted to engage said support to hold said sector-shaped member against rotary movement when the frame member is oscillated about said pivot point.

19. An involute form dresser for grinding wheels, comprising a support, a frame member oscillatable about a pivot point on said support, a dressing tool slidably carried by said frame member and presented radially to the peripheral edge of said grinding Wheel for movement along an involute pathway on opposite sides of the center line of said grinding wheel, a sector-shaped member secured to said support, a movable bar member drivingly'engaging said sector-shaped member, a sine b-ar pivoted to said bar members, and a sliding connection between said sine bar and said dressing tool to cause said tool to inscribe an involute contour on a grinding wheel surface as the frame member is oscillated about its pivot point, said depressing tool being reversible to positions'on opposite sides of the centerline of said grinding wheel to permit the dressing of either side of said grinding wheel adjacent the peripheral edge thereof.

CARL PETERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,148,955 Molly Feb,v 28, 1939 2,237,975 Wainwright Apr, 8, 1941 FOREIGN PATENTS Number Country Date 621,506 France May 12, 1927 842,033 France June 5, 1939 253,089 Great Britain 1926