US1795901A - Trimmer mechanism - Google Patents

Description

March 10, 1931. SLQCUM ET AL 1,795,901

- TRIMMER MECHANISM Filed Sept. 9, 1927 5 sheets-Sheet 1 VENTORS wmys; l

Buffer! H. acurn, 7M eph A. Bous/ough &

e andB/T Burn/1am WWW March 10, 1931. B. H. SLOCUM ETAL 1,795,901.

TRIMMER MECHANISM Filed p 9 192'! 3 Sheets-Sheet 2 WITNESS 2 I INVENTORS $14! Burfan H. Slacum,

Jase 7h A. Bo -Slough & W, I 2 u YF. Jrnham ATTORNEY March 10, 1931. B. H. SLOCUM ETAL H 1,795,901

TRIMMER MECHANISM Filed Sept. 9, 1927 3 Shoots-Sheet 3 INVENTOR5 WITNESSES:

Bur for! H. Slocum,

Leland E Burnbam Joseph A. boualough 8 wwaw V Patented Mar. 10,- 1931 UNITED STATES PATENT OFFICE BURTON H. SLOCUM, JOSEPH A. BOUSLOUGH, AND LELAND FLIBURNHAM, OF PITTS- IBURGH, PENNSYLVANIA, ASSIGNORS, BY MESNE ASSIGNMENTS, T'O WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA TRIMMER MECHANISM Application filed September 9, 1927. Serial No. 218,390.

The invention "relates generally to Wheel trimming devices and more particularly to trimming devices for abrasive wheels'of a type suitable for grinding purposes.

An object of our invention is to provide a device for trimming the working surfaces of abrasive wheels to a contour suitable for grinding gear teeth and which may be util-.

ized to trim abrasive wheels for grinding gear Wheels of any desired involute toot form, pitch or diameterj Heretofore trimmer mechanisms utilized for trimming the working faces of abrasive wheels to form contours suitable for grinding gear teeth have been provided with a cam'or template to guide the trimming member. The working surface of the cam was made either similar to. or identical in shape with the tooth contour it was desired to pro- 'vide, or the cam was made of an entirely dissimilar shape in order to impartthe proper motion to the trimming member through the medium of a compound linked mechanism. However,'these machines had the inherent disadvantage of indirect operation and the resulting inaccuracies introduced by loos'e-.

ness or deflections in the connecting link mechanism. Further, very carefulworkmanship was required in the/construction and operation of such machines to produce accurately trimmed abrasive wheels.

The present invention relates to a trimming device for abrasive wheels that.

may be utilized in grinding gear teeth, and that operates upon the principle of direct generation of the desired tootlf contour including the involute or working portion, the flank and the root fillet of the tooth upon the working faces of the abrasive wheel.

porting base, a frame member pivotally mounted on the supporting base and a pair of spaced cylindrical "segments, of diameter The device comprises in general a supfrom tangential or radial displacement with respect thereto. 1

An arcuate trimmer arm is pivotally mounted on the tangent bars and latched to the connecting member between the bars. A trimming member such as a cutting diamond is adjustably mounted on the trimmer arm in such-manner that itlies in the plane described by the bearing facesof thetangent bars. Adjusting means are provided to regulate the an angular position of the cylindrical segments with respect to the frame member in order to provide working faces of the proper width on the abrasive wheel to correspond with the desired tooth space of the gear wheel to be ground. e V

In operation, the abrasive wheel to be trimmed is rotated at a moderate speed and slowly fed into engagement with the trimming member. The tangent bars are rolled on the cylindrical segments to cause the trimmer member to describe an involute curve from the base circle outward to trim the abrasive wheel to the shgpp of the working portion of a ear tooth. e tangent bars may then be he (1 stationary in a predetermined limited position and the trimmer arm unlatched-from them and oscillated about itspivotal axis to cause the trimming member to describe an are from the base circle inward to trim the abrasive wheel to a contour suitable for grinding the flank and root fillet of a gear tooth. After the trimming operation has been completed on one sideof the abrasive wheel the frame may be turned upon the pivotal supporting base and accurately set in'the proper position to trim the other side of the wheel to an identical contour.

- In the accompanying drawing,

Figure 1 is a plan view partially in crosssection of a wheel trimming device embodying the principles of our invention;

Fig. 2 is a view in end elevation of the. trimming device of Fig. 1;

Fig. 3 is a viewin side elevation thereof. Fig. 4 is a view in section of a portion of 1 the trimming device taken along the line IV-IV of Fig. 1 {and Fig. .5'is 'a view in section of the trimmer arm ivot mechanism taken along the line V- of Fig. 4.

Referring to the drawing, the illustrated embodiment of the invention comprises a supporting base or center plate 1 that is adapted to be secured to a machine frame 2 by means of bolts 3. A center pin 4 is pressed into the base 1 and a frame or trunnion supporting member 5 is disposed on the pin in such manner as to permit it to be set in dif- 5 may be given an angular movement of sub-' stantially 180.

T slots 13 are provided in the end portions of-the frame 5 and extend parallel to each other and parallel to the center pin 4. In

T order to mount a base circle adjusting arm 17, square headed bolts 14 provided with nuts 15 are mounted in the T slots 13 to serve as trunnions to receive sleeve bearings Two cylindrical segments 18 having clamping hubs 19 and clamping bolts 21 are mounted upon the bearing sleeves 16 and clamped thereto. The cylindrical segments 18 have radii equal to the radius of-the base circle of "the gear wheel for which an abrasive wheel is to be trimmed. The adjusting arm 17 is provided with an opening 22 in its mid porbars 31 and 32, respectively.

tion for receiving a stop pin 23. As shown in Fig. 1, the stop pin 23 is provided with a square head 24 and is mounted in a T-slot 25 in the frame 5 in such manner that it maybe adjusted parallel to the center in 4 and locked in any predetermined position by a nut 26.

Adjusting screws 27 and 28 are provided in the adjusting arm 17 for engaging the stop pin 23 to turn the adjusting arm-17 and the attached segments'18 about the trunnion bolts 14 for a purpose to be hereinafter de-' scribed. I a I Tangent bars 31 and32 having an integral connecting bar 33 are mounted upon the peripheries of the segments 18 in such manner that they are free to roll thereon and are restrained from axial displacement with re-' 1spect thereto by the engagement of segment anges 36 in grooves 34 and 35 in the tangent bars 31 and 32 and t e segments 18 are provided with alined grooves 37 j and 38 respectively in their engaging 'faces for reins in the positions to 1 formed integral with the adjusting arm 1 The tangent ceiving wires 44 and 45 disposed to prevent tangential displacement of the tangent bars with respect to the segments 18.

Lugs 40 and 41 are provided upon the connecting bar 33 for receiving adjusting screws 42 and 43. 1

One end of each of the wires 44 and 45 is attached to the adjusting screws 42 and 43, respectively. The wires 44 and 45 pass around knobs 46 and 47 respectively on the connecting bar 33, through the grooves 38 and 37 in the tangent bars and segments and are secured at their other ends toscrews 48 in the segments 18. 1

Other wires 51 and 52 have both their ends secured to screws 53 mounted in the segments 18 at the ends opposite to those occupied by the screws 48. .The wires 51 and 52 are doubled and pass through the slots 37 and 38 in the segments and tangentbars respectively in such manner that the two portions of them occupy positions at either side of the wires 44 and 45. The looped portions of the Wires 51 and 52 are guided by suitable knobs and are passed around small pulleys 54 and 55 that are pivoted on adjusting screws 56 and 57.

Independent mechanical means are. pro vided in the form .of wheeled carriages 61 and 62 that are mounted upon the tangent bars and supported radially from the trunnion sleeves 16 to keep the tangent bars in cont-act with the segments 18. The faces of the tangent bars 31 and 32 opposite to the ments 18 are provided with central grooves 63 that are adapted to engage flanged wheels 64 of the carriages 61 and 62.

The carriages 61and '62 comprise frames 65 that are substantially rectangular metal blocks provided with slots at either end in which the flanged wheels 64 arepivoted upon axles 66. A plate 67 is provided upon each carriage to serve as an anchor for the ends of wires 68 that extend from the carriage around small grooved pulleys 69 which are journaled upon. thebearing sleeves 16 at either side of the segment clamps 19. This arrangement provides a doubled wire extending from the carriage to the trunnion assembly on each side of the segments 18. 7

An adjusting screw 71 having a locking llt.

nut 72 is threaded in the plate 67 and bears upon the carriage frame 65. The purpose of this adjusting screw is to lift the plate 67 from the carriage frame 65 thereby applying tension to the wires 68 and forcing the carriage into engagement with the tangent bar to. prevent radial displacement of the bar with respect to the segments 18.

Stop discs 81 are mounted upon arms 82 that are extensions of the frame 5.-' The discs are mounted in the same plane with the segments 18 and serve as stops for the tangent 95. For the purpose of pivoting the-trimmer arm 95 on the eccentric arms 86 and 87, the

openings 88 and 94 are provided with eccentric discs 91 and 93, respectively.

As shown in Figs. land 5, each of the discs- 91 is provided with two tapped holes 90 disposed at difier'ent distances from the center for receiving a pivot pin 92. Also, each of the discs 93 is provided with two cone bearing surfaces 100 for receiving the end of the'pivot pin 92, in such manner that the trimmer arm 95, when mounted, is free to be turned rclative to the tangent bars 31 and 32 about an axis through the centers of the pivot pins 92.

The purpose of mounting the pivot pins 92 in eccentric discs is to rovide means for changing the position of t e pivot axis of the trimming arm 95 with respect to the tangent bars 31 and 32. In operation, the pivot pin 92 is inserted in either of the holes 90, and

. the discs 91 and 93 are turned within the openings 88 and 94 until the desired setting of the pivot centers is obtained. The discs 91 and 93 may then be clamped in position by means of clamping screws 89. The posit-ion of the pivot pin 92 with respect to the trimming. arm 95 may be ascertained by means of graduations 96 that are provided on the periphcries of the eccentric discs 93.

to the connecting bar 33 by means of the latch 98. A trimming member 101 such as a cuttin diamond is mounted within the cylindrica portion 97 of the trimmer arm 95 by means of a threaded diamond holder 102.

The diamond holder 102 may be adjusted longitudinally of the cylindrical handle 97 by means of its threaded engagement therewith and'may be locked in any desired position by means of lock nuts 103.

An abrasive wheel 105 to betrimmed may be rotatably mounted upon a suitable arbor 106 in such position that its axis is at rightangles to the axis of the center pin 4 and also perpendicular to the plane passing through the axis of the pivot in 4 and the axis of the,

The trimmer arm 95 is provided at its center with acylin- 'drical handle portion 97 which may be latched by the segments 18 at a distance equal to of the tooth space, as measured on the base circle of the gear wheel to be ground, from the center line of axis of the pivot pin 4 when the tangent bars 31 and 32 are'in engagement with the stop discs 81.

The Wheel 105 to be trimmed may then be rotated at a moderate speed and fed into light engagement with the. trimmer member 101. The tangent bars 31 and 32 together with the trimmer arm 95 and trimmer holder 102 may then be rolled upon the peripheries of the seg ments 18 to cause the trimming point 101 to describe an involute curve which corresponds to the contour of a gear tooth from the base circle to the tooth tip. Successive cuts are taken from the abrasive wheel 105 in this manner until the desired contour is obtained.

The trimmer arm 95 may then be unlatched from the connecting bar 33 by releasing the latch 98 and pivoted about the pivot pin 92 to cause the trimmer member 101 to trim the periphery of the abrasive wheel to an arouate contour that is adapted for grinding the portion of a gear tooth from the base circle to the root of the tooth, which is also known as the flank and root fillet of the gear tooth.

When one face of the abrasive wheel 105 hasbeen trimmed to provide the proper contour, the clamping bolts 6 in the frame 5 may be released and the entire frame and attached mechanism may be rotated about the center pin 4 through an angle of 180, as determined y the stop pin 11, to the proper position for ilignming the other face of the abrasive wheel As viewed in Fig. 1, the trimmer mechanism may be rotated clockwise about the center pin 4'until the gauge pin 8 comes into engagement with the stop pin 11. The trim ming operation may be repeated on the second face of the abrasive wheel, thereby providing two working faces adapting it to grind the ad'acent faces of two gear teeth.

t is evident from the foregoing description of the invention that a trimmer mechanism made in accordance therewith is adapted to accurately trim the working surfaces of an involute tooth form or diameter. A further advantage is obtained by constructing our trimmer mechanism in such manner that the same trimming member and guiding mechanism may be used to trim each side of the abrasive wheel thereby ensuring exactly the same contour on each side thereof.

Although we have described a specific embodiment of our invention, it will be obvious to those skilled in the art that variousmodifi cations may be made in the details of construction and the design and proportions of the several cooperating parts of our trimmer mechanism without departing from the spirit and scope of the invention as set forth in the appended claims.

We claim as our invention:

1. A trimmer mechanism 4 for abrasive wheels comprising a base member, a frame pivoted on the base member, cylindrical segments pivoted on said frame about their aligned geometrical axes, said segments having their axes disposed at right angles to the pivotal axis of the frame on the base member, tangent bars mounted to roll upon said seg- 1ments and a trimmer secured to said tangent Mrs. A

2. A trimmer mechanism for abrasive Wheels comprising a base member, a frame supported on said base member, a plurality of cylindrical segments pivoted on the frame, tangent bars mounted on the segments and adapted to roll thereon, and a trimmer member pivoted to the tangent bars and adapted to roll with them or to pivot independently of them to trim the abrasive wheel.

3. A trimmer mechanism for abrasive Wheels comprising a base member, a frame carried by the base member, a plurality of cylindrical segments mounted .on the frame, tangent bars adapted to roll on the peripheries of the segments, a trimmer carried by the tangent bars, means for preventing the tangential displacement of the tangent bars and means comprising wheeled carriages mounted on the tangent bars and radially supported from the centers of the segments for maintaining the tangent bars in contact with the segments.

4. A trimmer mechanism for abrasive wheels comprlslng a base member, a frame member pivoted on the base member, cylindrical segments having their geometrical axes pivoted upon the frame member at right angles to the pivotal axis of said frame member, tangent bars mounted upon the peripheries of the cylindrical segments, said bars being free to roll thereon and restrained from tangential-displacement with respect thereto, a trimmer memberpivoted to the tangent bars, means for latching the trimmer member to the tangent barsand means for adjusting the pivotal center" of the trimmer member with respect to the tangent bars.

5. In a mechanism foftrimmingjabrasive wheels forgrindingv'g'ear teeth} segment of radius equal to theb cylindrical ase circle radius of the gear-wheel to be ground, a tangent bar adapted to roll upon the periphery of the segrrfent, atrimmer arm pivoted and latched to said tangent bar, a trimmer point carried by the trimmer arm, a stop member for engaging the tangent bar when the trim mer point is on the periphery of the base circle, said trimmer arm being adapted to pivot to trim the wheel to an arcuate contour within the base circle.

6. A trimmer mechanism for abrasive Wheels COIHPI'ISIIIg a base member,-a frame member, cylindrical segments pivoted on the frame member, means for, adjusting the angular position of the frame member with respect to the base member, means for adjusting the angular position of the segments with respect to the frame member, tangent bars disposed to roll on the segments, a trimmer arm carried by the tangent bars, and a trim mer mounted on the trimmer arm.

7. A trimmer mechanism for. abrasive wheels comprising a cylindrical segment, a tangent bar mounted to roll upon the periph- -ery of said segment, a trimmer arm pivoted trimmer arm pivoted to said tangent barf'a trimmer carried by the trimmertarm and means for adjusting the pivot center of said trimmer arm relative to the tangent bar in a plane at right angles to the axisof the cylindrical segment.

In testimony whereof, we have hereunto subscribed our names this 16th day of August, 1927 BURTON H. SLOCUM. I JOSEPH A. BOUSLOUGH. LEL AND F. BURNHAM.

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