US2335341A - Wheel dresser for gear grinding machines - Google Patents

Description

Nov. 30,1943. c. KNOWLES VETAL 2,335,341

WHEEL DRESSER FOR GEAR GRINDING MACHINES Filed Aug. 1, 1942 2 Sheets-Sheet 1 lllllllllllll INVENTOR CKnoa/Zes ATTORNEY Patented Nov. 30,

2,335,341 wnnm. DRESSER ron dnsncnmnmo monmns Carroll Knowles, West Hartford, and Arthur L.

Wilder, Wethersfleld, Comm, assignors to Niles- Bement-Pond Company, West Hartford, Conn, a corporation of New Jersey Application August 1, 1942, Serial No. 453,226

Claims. (Cl 125-11) This invention relates to wheel dressing devices and particularly to a wheel dressing or truing device for application to gear tooth grinders.

A primary object of the present invention is to provide means to dress the central peripheral portions of a bevelled grinding wheel to a smooth,

continuous, non-circular contour merging into the opp sitely bevelled side surfaces so that the clearance surface between the roots of adjacent teeth-of a gear may be ground simultaneously with the flanks of the gear teeth and the entire surface of the gear spaces finished to a smooth, continuous surface from one tooth to the next.

One feature that enables us to accomplish the above object is that the dressing device includes two obliquely movable dressing tools preferably mounted for slidable movements on supporting bars, these bars being positioned to pass their diamonds over and dress the bevelled surfaces of the wheel at predetermined oblique angles to each other, and there being a supplementary oscillatory dressing tool mounted upon one end of a lever pivotally mounted intermediate its length adjacent the slidable dressing tools so that as this supplementary dressing tool is oscillated with its lever the lever may tilt or swing about an intermediate point, the swinging movement of the lever about this pivotal point being controlled by a suitable template engaged by the end of the lever opposite the dressing tool and serving to traverse the dressing tool in a continuous curve of generally arcuate form disposed centrally between the paths of motion of the slidable dressing tools.

Another object of the invention is to mount the oscillatory lever carrying the supplementary dressing tool upon a central anti-friction bearing having a spherical bearing surface upon which the lever may pivot so that during the oscillatory movements of this dressing tool it may swing about the center of this spherical supporting surface.

And finally it is an object of the invention to control the oscillatory movements of this supplementary dressing tool in timed relation to the reciprocatory movements of the slidably mounted dressing tools and to control the pivotal movements of the supplementary tool in predetermined adjustable curved paths determined by the adjustment of the oscillatory dressing tool and the form of the template,

With the above and other objects in view, the invention may includethe features of constructicn and operation set forth in thefcllowing specification and illustrated in the acompanying drawings.

In the accompanying drawings annexed hereto and forming a part of this specification, we have shown the invention embodied in a dressing device generally similar to that shown and described in the patent to Tanner No. 2,086,750, granted July 13, 1937, but it will be understood that the invention can be otherwise embodied and that the drawings are not to be construed as defining or limiting the scope of the invention, the claims appended to this specification being relied upon for that purpose.

In the drawings:

Figure 1 is a front elevation, partly in section,

of a dressing device for gear grinders in which the present invention is incorporated.

Fig. 2 is a side elevation in section showing the oscillatory dressing attachment and its mounting and actuating mechanism.

Fig. 3 is an end view of the lever carrying the oscillating and pivoting dressing tool showing its actuating connections.

Figs. 4 and 5 are diagrammatic views showing different relative positions of the obliquely slidable dressing tools and the oscillating dressing tool assumed during their dressing operation upon agrinding wheel.

Fig. 6 is a diagrammatic view on an enlarged scale showing the curved form of the central peripheral portions of a grinding wheel and a template outline for producing this curve, and

Fig. 7 is a modified form of adjustable holder for the oscillatory dressing tool.

In the above-mentioned drawings there has been shown but one complete embodiment of the invention which is now deemed preferable, but it is to be understood that changes and modifications may be made within the scope of the appended claims without departing from the spirit of the invention.

Briefly, and in its preferred aspect, the invention may include the following principal parts; First, a dressing head mounted upon or forming a part of a gear grinding machine adapted to operate upon a tooth curve generating principle; second, two oppositely disposed dressing tools mounted upon suitable slidable members and manually actuatedin adjustable oblique direc tions through suitable operating connections; third, a supplementary dressing tool mounted for oscillatory movement between the slidable dressing tools upon one end of a lever free to tilt or pivot about an intermediate point; fourth, a template controlling the tilting movement of the lever; during its oscillatory movement: and

fifth, means to adjust the position of this tool 7 at predetermined distances radially from the axis of oscillation of the lever.

In grinding gears upon the involute generating principle, it has been the practice to dress the sides of a single bevelled grinding wheel to appropriate conical angles. The angle at which these sides are bevelled may vary but they are usually dressed along straight lines and at equal angles to the central plane of the wheel. These bevelled side portions of the wheel effect the grinding of adjacent sides of adjacent teeth. At present the central peripheral portion of the wheel disposed between the opposed bevelled side surfaces is usually dressed off by a special tool to form a narrow cylindrical surface intersecting the opposed bevelled surfaces of the wheel at sharp angles. v

The present invention provides means to traverse a dressing tool over the central peripheral portion of the wheel in a smooth, continuous curve of 'modified'arcuate form intersecting the bevelled side surfaces at widely obtuse angles so that clearance portions between the teeth at the bottom of the tooth spaces may be ground over their entire area simultaneously with and to form a continuous curve with the flanks of the gear teeth.

Referring more in detail to the figures of the drawings, we provide a suitable housing ill for a complete dressing device for the bevelled wheel W of a gear grinder in which there are provided oppositely disposed slidably mounted bars 52 having dressing tools it upon their lower ends. By

suitable connections similar to those shown in the above-referred to patent, these members it are reciprocated so that their dressing tools it are moved over the opposed bevelled surfaces of the wheel W. The connections for actuating these dressing tools are such that when one of the dressing tools i3 is at its lowermost position the opposite dressing tool is at its uppermost position.

Also actuated from the same driving connections for the slidable bars i2 which may include a manually rotatable shaft id is an oscillating dressing tool it disposed intermediate the positions of the slidable dressing tools it. This dressing tool is is adapted, as shown in the figures, to dress the central peripheral surface of the wheel between the opposed bevelled portions of th wheel. As shown most clearly in Fig. 2, this oscillatory dressing device has its dressing tool mounted upon one end of a lever it. Preferably the dressing tool comprises a diamond i5 inserted in the lower end of the adjustable holdler ll positioned within the forward end of this lever 66. As shown in Fig. 2 this dressing tool i5 is disposed substantially in alinement with the axis of oscillation of the lever. Locating means for the tool 65 are indicated in Fig. 2 to position the tool at any desired but limited distance radially from the axis of the lever.

In order to support this lever it for oscillatory and tilting movements there is provided an intermediate anti-fi'iction bearing l8 having a spheri cally formed bearing surface upon its outer race so that the lever l6 may, in addition to its oscil-' erably upon anti-friction bearings within the housing i0 and having a' bevelgear 20 mounted thereon drivingly connected to one of the driving connection for the slidably mounted dressing tools l3. This sleeve l9 surrounds the lever i6 at its end remote from the dressing tool 85, there being a large enough opening within the sleeve to permit limited swinging movements of the lever about the center of bearing l8. To connect the sleeve l9 and lever i6 so that they will oscillate together while permitting the lever to swing, the rear end of the lever It has formed thereon an extension 24 having fiat parallel sides which en- 1 gage opposed parallel surfaces on the end portions of the sleeve I9 which is slotted for that purpose.

.To'limit the swinging or pivotal movement of the dressing tool l5 about its supporting bearing 88 there is provided a suitable template 2! secured rigidly to the casing surrounding the sleeve 59 and having a stud 22 passing radially through the sleeve., The form of the template surface is determined by the form of surface to be generated at the central periphery of the wheel and may be ofthe form shown upon an enlarged scale in Fig. 6. The outer end of the stud 22 engages the template surface 2| and the inner end of the stud presses against the surface of the lever IS. A compression spring 23 housed within the lever forces the lever laterally against the stud 22 and in turn presses the stud 22 against its template 2|.

In operation, by rotating the shaft carrying the worm M by the hand lever 9 shown in Fig. 1, the slides 52 and their dressing tools 53 are reciprocated over the bevelled side surfaces of the wheel W. Simultaneously, through the driving connections for these slides i2 and the bevel gear 20 the sleeve l9 surrounding the rear end of the oscillatory lever I6 is actuated. The movement or this dressing tool it and lever Hi imparted to them by the sleeve 69 is an oscillatory one, and as the dressing tool i3 is disposed a limited but adjustable distance from the axis of the lever or member it, limited oscillatory movement is induced to the dressing tool i5 by this movement. However, simultaneously with the oscillatory movement of the lever it it is pivotally moved about the center of its central supporting bearing l8 by means of the template 2| so that the dressing tool i5 traces a smooth but non-circular curve determined by the outline of the template 2| and by its radial distance from the axis of lever l6. Essentially the curve traced out by the dressing tool [5 is generally arcuate, dependent upon the radial distance of the tool from the axis of lever l6 modifled slightly by the conformation of the template outline 2I.- This curve is such that the central dressing tool l5 at the opposite ends of its movement blends or merges into the path of movement of the slidably' mounted dressing tools to form a continuation therewith. The entire active surface of the grinding wheel is therefore dressed to a smooth and predetermined conformation. The clearance surface at the root of the tooth flanks between adjacent gear teeth is therefore finish-ground at the same time the involute tooth surfaces are ground.

To adjust the position of the dresser E5 toward and from the axis of oscillation of the lever l6, gage blocks of the required distance may be inserted between the dresser and a surface of a bracket mountable on the outer end of the lever. As shown in Fig. 2, the bracket 25 is removable and has its surface upon which the gage block is placed in alinement with the axis of oscillation of-the lever I6.

In Fig. "I there is shown a holder for the dressing tool l that permits adjustment laterally as well as radially of the dressing tool. Commercial diamonds vary over such a wide range of shapes and sizes that the holder to accom modate these variations is made adjustable. As shown in this figure the dressing tool end of the lever I6 is provided with a plane surface end against which is mounted a diamond holding block 26 adapted to'slide vertically in a suitable slideway and be held in adjusted position by a screw 2'1. The block 26 carries an adjusting screw 28 by means of which the vertical position of the block 26 may be determined. The block 26 also carries a bushing 29 having a hole extending vertically therethrough disposed eccentrically of the axis of the bushing. Within the hole in the bushing 29 is the dressing tool 30 mounted within the end of a spindle 32 extending through the eccentric 'hole. This spindle 32 and tool 30 may be held in their uppermost position by a nut 33 threaded on the upper end of the spindle. By rotation of the bushing. 29 the diamond cutting point l5 of the dressing tool 30 may be adjusted laterally so that its point will be in alinement with the axis of the lever 16.

A screw 3i servesto clamp the bushing in ad-' justed rotative position.

We claim:

1. A dressing device for grinding wheels comprising in combination, an elongated member having a dressing tool mounted at one end, means to oscillate said member about its longitudinal axis, a supporting bearing for said member intermediate its length about which said member may oscillate and pivot, and template means to control the pivotal movement thereof about said bearing.

2. A dressing device for grinding wheels comprising in combination, an elongated member having a dressing tool mounted at one end for adjustment radially toward and from the axis of said member, means to oscillate said member about its longitudinal axis, a supporting bearing for said member intermediate its length about whichsaid member may oscillate and pivot. and template means to control the pivotal movement thereof about said bearing.

3. A dressing device for grinding wheels comprising in combination, an, elongated member having a dressing tool mounted at one end. means to position said dressing tool at predetermined adjustable distances from the axis of said member. means to oscillate said member about its longitudinal axis, a supporting bearing for said member intermediate its length about which said member may oscillate and pivot, and template means to control the pivotal movement thereof about said bearing during its oscillatory movement.

4. A wheel dressingrdevice for gear grinders comprising in combination, an elongated member pivotally supported intermediate its length and adapted to be oscillated about its longitudinal a dressing tool at one end of said mem ber, guiding means for said member adjacent its opposite end whereby said tool during oscillation about its longitudinal axis will have a limited swinging movement whereby said dressing tool will traverse a symmetrical non-circular path, and an-anti friction bearing supporting said member at an intermediate point about which said member may pivot and oscillate.

5. A wheel dressing device for gear grinders comprising in combination, an elongated mamber pivotally supported intermediate its length and adapted to be oscillated about its longitudinal axis. an anti-friction bearing having a spherical seat within which said member may pivot, a dressing tool at one end of said member adjustable radially toward and from the axis of said member, and guiding means for said meanher including a template mounted adjacent its opposite end whereby said tool during oscillation about its longitudinal axis will traverse a symmetrical curved path.

CLL KNOWLES. ART L. ER.

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