US2476322A - Involute form dresser - Google Patents

Description

July 19, 1949. c. PETERS INVOLUTE FORM DRESSER 4 Sheets-Sheet 1 Filed April 24, 1946 J Car/5 67 55 5 mm Wfiu 4 Sheets-Sheet 2 r1 /Il.|

July 19, 1949. c. PETERS INVOLUTE' FORM DRESSER Filed April 24, 1946 July 19, 1949. c. PETERS 2,476,322

INVOLUTEI FORM DRESSER Filed April 24, 1946 4 Sheets-Sheet I5 I e f car/Z 957? z fladzdffl y 2/40/91;

July 19, 1949. c. PETERS I INVOLUTE FORM DRESSER 4 Sheets-Sheet 4 Filed April 24, 1946 5455 C/ECLE.

Patented July 19, 1949 UNITED "STATES PATENT OFFICE INVOLUTE FORM DRESSER Carl Peters, Dearborn, Mich.

Application April 24, 1946, Serial No. 664,629

' 12 Claims. (01. 125-11) This invention relates to grinding wheel dressing tools, and in particular, to a dressing tool for forming an involute contour on the edge of a grinding wheel.

One object of the invention is to provide a grinding wheel dressing tool which is so constructed and arranged as to impart a true involute form to the grinding wheel of a gear grinding machine.

Another object is to provide a grinding wheel dressing toolin which the involute curve or path of the cutting member is generated indirectly through a pinion and rack so that the periphery will be developed from the pitch line of said rack.

Another object is to provide a grinding wheel dressing and surface cutting tool in which the acceleration of the cutting member or diamond point is accomplished through the use of tangent trigonometric functions, thus eliminating the considerable computations otherwise required in correctly setting the dressing tool to cut a particular involute curve.

Another object is to provide a grinding wheel dressing tool in which the slide frame is arranged for vertical to and fro translatory movement, thereby providing a dressing tool which is compact and consumes only asmall amount of space.

Another object is to provide a grinding wheel dressing tool which is so constructed as to enable the same to be set-by simple computations involvingonly division and multiplication, in an easy manner to cause the dressing tool, such as a diamond point cutter, to move along a path, all points of which are on a true involute curve.

Another object is to provide a grinding wheel dressing tool which will develop an involute form between the peripheral and radial walls of a grinding wheel in substantially the same manner as the involute gear tooth profile is generated, thus producing as nearly as possible the correct form on the grinding wheel fora prescribed tooth profile.

Other objects and advantages of the invention will become apparent during the course of the following description of the accompanying drawings, wherein: r I

Figure 1 is a front elevation of the grinding wheel dressing tool, with the various parts in neutral position andthe accelerating member set at an angle of 45;

Figure 2 is a vertical section through the dressing tool, taken on the irregular line 2-2 of Figure 1; r

Figure 3 is a vertical section .takenon the line 3'-3 in Figure 2 and showing how the accelerating member is angled and held in a predetermined adjusted position;

Figure 4 is a horizontal cross-section taken on the line 44 in Figure 1;

Figure 5 is a horizontal cross-section taken on the line 5-5 in Figure 1;

Figure 6 is a front elevation similar to Figure 1 but showing the position attained by the dressing tool when the rotatable frame is turned through a partial revolution;

, Figure 7 is an enlarged fragmentary view showing the position of the diamond cutting member reversed to dress the opposite edge of a grinding wheel; and

Figure 8 is a diagrammatic view showing the angle :r:a: of tooth space formed between the involute profiles of a gear at the base circle.

Referring to the drawings in detail, Figures 1 and 2 show a preferred embodiment of the grinding wheel dressing tool as comprising a base 5 having a perfectly fiat bottom wall 6 which is adaptedto be mounted on the bed of a gear grinding machine. The gear grinding machine is of any conventional type having a shaft S carrying a grinding wheel W.

Extending upwardly from the base 5 and formed integral therewith is an upright I having a bearing boss 8 at its upper end provided with a bore 9 surrounded by an annular recess l0. Seated in the annular recess [0 is the flange l l of a pintle l2; one end l3 of which is mounted in the bore 9'and is held therein by means of a retaining bolt l4 and washer l5. Adjacent the flange H is a reduced diameter portion l6 upon which is journalled the bearing bore 18 of an oscillatable frame plate IT. The pintle l2 terminates in a reduced I diameter end portion. l9 upon which is fitted a fixed gear 26 secured to the pintle l2 by screws 2| threaded into ho1es 22 therein.

Secured as by the screws 25 to the circular portion of the frame plate [1 is the annular flange 24 of a circular housing 23 (Figure 2). The latter has a central boss 26a with a bearing bore 21 journalled on the end'portion IQ of the pintle l2 so that the housing 23 and frame plate I! may be rotated thereon by means of a handle 26 mounted thereon. Extending radially upward from the frame plate I! and housing 23 respectively are plate- like projections 28 and 29. The projection 29 has fianges 30 along its edges to which the projection 28 is secured as by the screws 30a. The passageway thus formed slidably receives a rack bar 3| having teeth 32 vmeshingwith and drivingly engaged by a pinion 33.

The pinion 33 is formed with integral hub portions 34 which are journalled in aligned bearing bores 35 and 36 respectively in the frame plate extension 28 and the housing extension 29. Thus rotation of the frame plate I! and housing 23 about the pintle [2 causes the pinion 33 to roll on the fixed gear 20 and reciprocate the rack bar 3 I.

The housing 23 and its. extension 29- carry dovetail guides 38 and 39; in which is mounted an elongated dovetail slide 49. Secured by the screws 42 and 43 to the upper ends of the slide 40 and rack bar 31 is a bridge piece 44, Pivotally mounted on i the lower portion of the slide 46 is anaccelerator 45. For this purpose the latter is providedwith a stepped bore 41 journalled on a pivot pin 48 secured to the slide 40 by a screw 49z The slide 40 above the accelerator 46 is provided with a dovetail guideway 50 with a reciprocable adjusting slide 52 (Figure 6) carrying a pin 53 and a roller 54. Th'e la'tter engages a longitudinalslot 55in oneend of the accelerator 46. The adjusting slide 52"i's'provided with a slot 56 through which projects a threaded stud 51 seated in the slide 46 and: carrying a clamping thumb nut5'8. The slide 5'2is also provided with ajaw 59. (Figure 1) which cooperates with a jaw 66 carried by the slide 46 to receive precision gauge blocks therebet'ween.

The frame plate 11' (Figure 1) is provided with transverse projections 6| with forwardly extending arms 62 (Figure 4); Secured as at 620, to the arms. 62 are parallel guide bars 64 having guide grooves 65 receiving the corresponding ribs66 of a crossslide 83. Mounted in a bore 67 in the cross slide 63' is apivot pin 68 secured thereto by a retaining. washer I] and screw I2 (Figure 2).. The pivot'pin 68' projects forwardly from a swivel slide 69 having a groove 10 slidably engaging theaccelerator 46; V

Formed integral with andidepending from the cross slide 63 are. two spaced'parallel guide rails I4 (Figures 1 and 2) havingoppo'sed guidegrooves (Figure 4) The latter slidably. receive the lateral ribs E6 of a diamond tooLbracket 11 held in place by a retaining strip 18 which is secured to one of the depending. guide rails 14 by. thumbscrews 19. one ofthe depending guide rails 14 is provided with an arm forming a jaw 80 cooperating with a jaw 8| secured to. the slide bracket.

11 by screws 82. These serve. to. receive precision gauge blocks (not shown) for positioning.

the diamond tool as described below.

The slide bracket. 11' has a bracket arm 83 whichriscut away atits end'to form a seat 84 and avertical shoulder 65; The arm 63 is bored as at 86 to receive the short shaft portion 81 of an L-shaped bracket 88 heldiin place by a thumbscrew 89 threaded therein. The horizontal portion 96 of the bracket 88 is offset relatively to the axis of the short shaft portion '8'! to permit it to beturne'dto either side of. the grinding wheel W, whereas. the upstanding portion BL is provided witha transverse. bore '92 for receiving a cutting tool 93-held in place by a setlscrew 95 and having adiamondpoint 94.

operation In the operation of. the invention, the various parts of the.grindingwheelfdressing tool are adjustedso that the axisoffrotationof the housin 46; is set to theproper angular position for the base circle diameter ofthe' g'ea r to'b'e cut'by in serting between the jaws 59 and 69 a precision gauge block having a length A equal to one-third of the base circle diameter, the distance B (Figure 1) being fixed. For example, to set the accelerator 46 to grind a gear having a base circle diameter of six inches, a two inch precision gauge block is inserted between the jaws 59 and 60. The thumb screw 58 is then tightened to lock the block inthis position.

After the accelerator 46 has thus been angled and locked in position to give the proper acceleration to the cross slide 63, the diamond point 94 is then properly located so that the cutting point will'trace-an-involute curve starting from a point on the basecircle of the gear to be ground. This is done by inserting between the jaws 86 and BI another precision gauge block having a length C (Figure-2) equal to the radius of the base circle of the gear to be ground multiplied by the cosine of one-half of the angle" (at-:1: in Figure 8) of tooth space formed between the flanks of the involuteprbfiles' thereof at the base circle. With the proper precision gauge block thus located between the jaws, the thumb screws I9 are then tightened in placeto securely hold the slide bracket H in it'st-hus adjusted-position. The distance of thed'iamondcutting tool point 94 from the axis of the shaft portion 61' is then calculated by multiplying the sine of one-half of the above an'gleof'to'oth space at the base circle (x--ac in Figure 8) by'the radius (if the-base circle.

When the grinding wheel dressing tool is set as bove described; it placed on the bed or other support onthe' grinding machine with the diamond tip 94 in vertical alignment with the axis of'the' grinding shaft S. The handle 26 is then moved in a clockwise direction to cause angular displacement-of'thefho'using 23in a clockwise directionlo'oking' at Figure 6; In so doing,

the slide 40 (which carries the accelerator 46) will move down'wardly; causing the cross slide 63 to rn'ove along the guide rails 64 through the action of the angularly positioned accelerator 46 in the swivel slide block 69. The three movements combineto c'ause the diamond point 94 to cut an involute"eurve on'one edge of the grinding wheel periphery.

Theme'chanism of the present invention reproduces thematheniatical condition that the involute tangent equals the: developed circumference orth'earc which'isllriwound'from the base circle." In thesiinplified'icase ofthe involute proble' r'ryshown' in Figures 1' and-'6, where the base circle-of 'a'gear to beggrounde'quals the pitch circle of'the fi'xed gear zq, and where the accelerator 461s 'inclinedddfdegrees; themovement of the diamond point' 9 4f'et1ualsjthe movement of the accelerator-whichis being actuated by the rack bar 3!; This results irornthe'fact that the movementofth'e rack Bar 3i "equalsfthe developed circumfereiice ftlie nseafgear 26, this movement being project'edet right angles thereto by the accelerator 46 and imparted to the diamond point I 94j thereby following the successive involute 6'5" tangentsflcorre'spondin'g the successive arcs astheangu'lar displacement *or thehousing 23 is occasioned by the movementof the handle 26.

ldy'th'e; use "of: thedevice of th'e present invention, alI involiitejproblems d'ownfto zero base circle 70"dia'meter are re'solved with great fidelity when diamond setting C and accelera tor "46' setting A conformto "the f rmulati'ons as hereinafter set forth. The a cceleratbr' '46 isthe agent which, measures the involute tangents that correspond were The angularsetting ofthe "accelerator 46'is ac complished through similar triangles, the base of one of which always equals the fixed distance B in Figure 1; the distance A- will'always be Basecircle of the required gear A B equals Pitch circ leof fixed gear For example, let the pitch circle of the fixed gear" 20 be 6 inches, let the basecircle of-the required gear be 3 inches, and let B equal 2 inches. Thenby the above formula,

or A equals 1 inch. Thus in this example we find the A value to be of the base circle.

. 3 equals After one edge of the grinding wheel has been dressed or cut to impart an involute form. thereto, the position of the cuttingtool supporting bracket arm 9! may be reversed todress the other peripheral edge of the grinding wheel W. This is accomplished by merely loosening the thumb screw 89 a suficient distance, to permit the bracket block 88 to be unseated from the base surface 84 and shifted 180, whereupon the thumb screw 89 is again tightened. Afterthe grinding wheel has been used for grinding a number of gear teeth sufficient to cause wear in excess of the tolerances being observed, it is dressed from time to time to retrue its inaccurate surfaces.

While I have shown and described my invenmechanism responsive to the rotation of said frame for reciprocating said slide, a cross-slide reciprocably mounted on said frame at right angles to said slide, an accelerator member mounted on and adjustable angularly relativ-elyto said slide, a dressing tool holder connected-to said cross-slide, and mechanism responsive to the motion of said accelerator member bodily with said slide for reciprocating said cross-slide.

2. An involute form dresser for grinding wheels comprising a, support, a frame rotatably mounted on said support, a slide reciprocably mounted on said frame, a gear fixedly connected to said support, a rack reciprocably mounted on said frame and connected to said slide, a pinion rollable on said gear and meshing with said rack whereby to reciprocatesaid slide in resp t the rotation of said frame, a cross-slide reciprocably mounted on said frame at right angles to said slide, an accelerator member mounted on and adjustable angularly relatively to said slide, a dressing tool holder connected to said crossslide, and mechanism responsive to the motion of said accelerator member bodily with said slide for reciprocating said cross-slide.

3. An involute form dresser for grinding wheels cOl'i'lDllSlIlg a support, a frame rotatably mounted on said support, a slide reciprocably mounted on said frame, mechanism responsive to the rotation of said frame for reciprocating said slide, a cross-slide reciprocably mounted on said frame at right angles to said slide, an accelerator member mounted on and adjustable relatively to said slide, a reciprocable adjusting member slidably mounted on said slide, a coupling element interconnecting said accelerator member and said adjusting member, a locking device for securing said adjusting member in its adjusted position;

a dressing-toolholder connected to said crossslide, and mechanism responsive to the motion of said accelerator member bodily with said'slide for reciprocating said cross-slide. r

4-. An involute form-dresser for grinding wheels comprising a support, a frame rotatably mounted on said support,a slide reciprocably mounted on.

said frame, mechanism responsive to the rotation; of said frame for reciprocating said slide, a cross-- slide reciprocably mounted on said frame at right angles to said slide, an accelerator member mounted on and adjustable relatively to said slide-,,

a reciprocable adjusting member slidably mount-' ed on said slide, acoupling element interconnect-- ing said acceleratormember and said'adjustingt member in simultaneous sliding and swinging relationship therebetween, a locking device for' securing said adjusting member in its adjusted position, a dressing tool holder connected to said cross-slide, and mechanism responsive to the motion of said accelerator member bodily witlf' said slide for reciprocating said cross-slide.-

5. An involute form dresser for grinding wheels comprising a support, a'frame rotatably mounted on said support, a slide reciprocably mountedon said frame, mechanism responsive to the rotation of said frame for reciprocating said slide, a cross-" slide reciprocably mounted on said frame at right angles to said slide, an accelerator member mounted on and adjustable reiatively to said slide, a reciprocable adjusting member slid-ablymounted on said slide, a coupling element interconnecting said accelerator member and said adijusting member, a locking device for securing;- said adjusting member in its adjusted positidrr, cooperating opposed projections on said adjust-- ing member and slide respectively for receiving precision gauge blocks therebetween, a dressin g tool holder connected to said cross-slide, and mechanism responsive to the motion of said accelerator member bodily with said slide for reciprocating said cross-slide.

6. An involute formdresser for grinding wheels comprising a support,;a frame rotatably mounted" on said support, a slide reciprocably mounted on i said frame for movement diametrically and sub stantially through the axis of rotation thereof, mechanism responsive to the rotation of said frame for reciprocating said slide, a cross-slide reciprocably mounted on said frame at right angles to said slide, an accelerator member -mounted on and adjustable relatively to said" slide, a dressing tool holder connected to said cross-slide, and mechanism responsive to the motion of said accelerator member bodily with said slide for reciprocating said cross-slide, said accelerator member being pivotally mounted on said slide for angular adjustment relatively thereto.

7. An involute form dresser for grinding wheels comprising a support, a frame rotatably mounted on said support, a slide reciprocably mounted on said frame for movement diametrically and substantially through the axis of rotation thereof, a gear fixedly connected to said support, a rack reciprocably mounted on said frame and connected to said slide, a pinion rollable on said gear and meshing with said rack whereby to reciprocate said slide in response to the rotation of said frame, a cross-slide reciprocably mounted on said frame at right angles to said slide, an accelerator member mounted on and adjustable relatively to said slide, a dressing tool holder connected to said cross-slide, and mechanism responsive to the motion of said accelerator member bodily with said slide for reciprocating saidcross-slide.

8. An involute form dresser forgrinding wheels comprising a support, aframe rotatably mounted on said support, a slide reciprocably mounted on said frame, a gear fixedly connected to said support, a rack reciprocably mounted on said frame and connected to said slide, a pinion rollable on said gear and meshing with said rack whereby to reciprocate said slide in response to the rotation of said frame, a cross-slide reciprocably mounted on said frame at right angles to said slide-an accelerator member mounted on andadjustable relatively to said slide, a dressing tool holder connected to said cross-slide, and mechanism responsive to the motion of said accelerator member bodily with said slide for reciprocating said cross-slide, said accelerator member being, pivotally mounted on said slide for angular adjustment relatively thereto.

9. An involute form dresser for grinding wheels comprising a support, a frame rotatably mounted on said support, a slide reciprocably mounted on said frame, mechanism responsive to the rotation of said frame for reciprocating said slide, a crossslide reciprocably mounted on said frame at right angles to said slide, an accelerator member mounted on and adjustable relatively to said slide, a reciprocable adjusting member slidably. mounted on said slide, acoupling element interconnecting said accelerator member and said adjusting member, a locking device tor securing said adjusting member in its adjusted position, a dressing tool holder connected to. said crosseslide, and mechanism; responsive to. the motion of said accelerator member bodily; with said slide for reciprocating said, cross-slide, said accelerator member being pivotally mounted on said slide for angular adjustment relatively thereto.

1-9. An involute form, dresser for grindingwheels comprising a support, a frame rotatably mounted on said support, a, slide reeiprocably mounted on said frame, mechanism responsive tor the rotation of said frame for reciprocating said s ide, a cross-slidereciprocably mounted, on said;

frame at right angles tosaid slide, an: accelerator member mounted on; and, adjustable relatively to, said slide, a reciprocable adjusting member slid ably mounted on said; slide, a coupling element interconnecting; said accelerator member and, said adjusting member in simultaneous sliding; and swinging relationship therebetween a locking device for securing said; adjusting; memberin; its adjusted; posit/i0 8;v a dressing; tool: holder' connectedto said cross-sliddand mechanism ref 8: sponsive to the motion of said accelerator member bodily with said slide for reciprocating said cross-slide, said accelerator member being pivotally mounted on said slide for angular adjustment relatively thereto.

11. An 'in'volute form dresser for grinding wheels comprising a-support, a frame rotatably mounted on said support, a slide reciprocably mounted on said frame for movement diametrically thereof, a gear fixedly connected to said support, a rack reciprocably mounted on said frame and connected to said slide, a pinion rollable on said gear and meshing with said rack whereby to reciprocate said slide in response to the rotation of said frame, a cross-slide reciprocably mounted on said frame at right angles to said slide, an accelerator member mounted on and adjustable relatively to said slide, a dressing tool holder connected to said cross-slide, and mechanism responsive to the motion of said accelerator member bodily with said slide for reciprocating said cross-slide, said accelerator member being pivotally mounted on said slide for angular adjustment relatively thereto.

12. An involute form dresser for grinding wheels comprising a support, a frame rotatably mounted on said support, a slide reciprocably mounted on said frame, mechanism responsive to the rotation of said frame for reciprocating said slide, a cross-slide reciprocably mounted on said frame at right angles to said slide, an accel'erator member mounted on and adjustable relatively to said slide, a reciprocabl'e adjusting member slidably mounted on said slide, a coupling element interconnecting said accelerator member and said adjusting member, a locking device for securing said adjusting member in its adjusted position, cooperating opposed projections on said adjusting member and slide respectively for receiving precision gauge blocks therebetween, a dressing tool holder connected to said cross-slide, and mechanism responsive to the motion of said accelerator member bodily with said slide for reciprocating said cross-slide, said accelerator member being pivotally mounted on said slide. for angular adjustment relatively thereto.

CARL PETERS.

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

UNITED STATES PATENTS Number Name Date 2,237,975 Wainwright Apr. 8, 1941 2,376,109 Aeppli' May 15, 1945

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