US2281420A

US2281420A - drader

Info

Publication number: US2281420A
Authority: US
Publication date: 1942-04-28
Anticipated expiration: 1959-04-28

Description

April 28, 1942. J. c. DRADER BUILT-UP ABRAS IVE Filed April 15, 1936 Mill! lllllll mm 1 H INVENTOR.

735.9 [1' flrdd Patented Apr. 28, 1942 u r sa Ei i'l OFFICE BUKLT-UP ABRASIVE Joseph C. Drader, Detroit, Mich, assignor to Michigan Tool Company, a corporation of Delaware 1 Claim.

The present invention relates to gear finishing tools, and in particular provides an improved finishing tool having teeth of composite form.

The co-pending application of Paul F. Seibold, Serial No. 58,838, filed January 13, 1936, discloses an improved method and machine for finishing gears and other objects which, in its application to gear finishing, may be characterized as providing means for supporting a gear and a finishing tool in mating relation, rapidly reciprocating the tool relative to the gear in a path parallel to the tooth faces of the gear, and relatively slowly rolling the gear relative to the tool. Due to the relatively high ratio between the rate of reciprocation and the rate of rolling, all or substantially all of the finishing action is accomplished by the reciprocation. The tool teeth are preferably formed conjugate to the gear teeth and the improved method produces gears having teeth of accurate form, the deformation commonly produced in conventional gear finishing methods due to the roll of the gear and tool being substantially if not entirely eliminated.

Objects of the present invention are to provide an improved finishing tool, particularly suited for the practice of the invention disclosed in the above identified Seibold application, but also well suited for the practice of other gear finishing methods; to provide such a tool which is of composite form, embodying abrasive elements adhered to backing members, the abrasive elements being preformed to conform to the desired resultant gear tooth form; to provide such a tool in which the abrasive elements and backing members are rabbeted together; to provide such a tool in which the rabbet joint between the abrasive elements and the backing members extends substantially parallel to the pitch surface of the tool; to provide such a tool in which the rabbet joint between the abrasive elements and the backing members may extend substantially perpendicular to the pitch surface of the tool; to provide such a tool embodying Wedge means to retain the abrasive elements and backing members in assembled relation; and to provide a tool construction which may be embodied in either a tool of the circular or gearlike type or of the rack type.

With the above and other objects in view which appear in the following description and in the appended claim, preferred but illustrative embodiments of the present invention are shown in the accompanying drawing, throughout the several views of which corresponding reference characters are used to designate corresponding parts, and in which:

Figure l is a top plan View of a rack embodying the present invention;

Figure 2 is a fragmentary view in vertical section, taken along the line 2-2 of Figure 1;

Figure 3 is a fragmentary view in vertical section of a modified rack construction;

Figure 4 is a view in elevation showing an em bodiment of the invention in a tool of the gearlike type;

Figures 5, 6 and '7 are views illustrating a rabbeted construction;

Figures 8 and 9 are views illustrating a modified rabbeted construction;

Figures 10 and 11 are views of a further modified rabbeted construction;

Figure 12 is a fragmentary View illustrating a wedge construction; and

Figure 13 is a fragmentary view of a modified wedge construction.

Referring first to Figures 1 and 2, the illustration rack construction comprises a base member 20 having a longitudinally extending recess defined by the side walls 22, within which a plurality of

rack blades

24 and 26 are disposed, and are secured in place in abutting relation by the bolt 28 which passes longitudinally through the blades and the nuts 30 associated with which bear against the end walls 32 of the recess.

In accordance with the disclosure of the above identified Seibold application, the initial group of rack blades 24 are preferably of conventional construction, having the upper portions thereof tapered to form rack teeth 34 of form conjugate to that which it is desired to produce on the gear to be finished. These teeth serve, in operation, to initially position the gear relative to the rack.

The remaining blades 25 are, in accordance with the present invention, of composite form, and embody abrasive sticks 35 and steel backing members 38. The abrasive sticks are tapered in their upper portions to form teeth of form similar to the teeth 3t, and conjugate to the desired gear teeth. The bases 49 of the abrasive sticks are V or wedge-shaped and mate with corresponding V-shaped recesses formed in the backing members 38. The abrasive elements 36 and the back- 1 ing members 38 are firmly bonded together along the surfaces provided by the wedges and V- shaped recesses. The bonding may be effected in various ways, the exact adhesive or other bonding material utilized forming no part of the present invention.

In the modified ccnstruction shown in Figure 3, the separate backing members 38 of Figure 2 are replaced by a single backing member 42 provided with a plurality of successively disposed and parallel V-shaped recesses it to receive the abrasive elements 38. Similarly, the separate blades 24 are replaced by a single member 46, having the plurality of rack teeth 34 formed thereon.

In the embodiment shown in Figure 4, the

tool 50 is of the circular or gear-like type, and comprises the circular body portion having a plurality of V-shaped recesses 52 formed in the periphery thereof, each adapted to receive an abrasive tooth portion 54 of form conjugate to that which it is desired to produce on the gear. The abrasive elements 54 are bonded to the body of the tool in the manner described with reference to Figures 2 and 3.

In certain instances it is desirable to replace or supplement the adhesive bond between the abrasive elements and the backing members. In the embodiment of Figures 5, 6 and '7, this is accomplished by forming rabbet joints between the abrasive elements 60 and the backing members 62. Each rabbet joint is illustrated as extending substantially parallel to the pitch surface of the tool, and as being provided by the oppositely directed but similar rabbets 64 in each abrasive element and corresponding anchors or tongues 66 in each backing element. In assembly, each abrasive element and its corresponding backing member is disposed in end to end relation with the rabbet elements in registry with each other, and are then slid together. Retaining plates 68, secured to the backing members 62 by studs 10 are preferably provided to positively retain the abrasive elements and backing members against relative longitudinal movement.

In the just described construction, the longitudinally extending rabbet joints are particularly effective in withstanding stresses to which the abrasive elements are subjected due to the roll of the gear. In certain other instances, it is considered desirable to form a joint between the abrasive elements and the backing members so as to be particularly eifective in withstanding the stresses to which the abrasive elements are subjected due to the lateral reciprocation be tween the gear and the finishing tool. In Figures 8 and 9, this is accomplished by disposing the rabbet joints substantially perpendicular to the direction of relative reciprocation between the finishing tool and the gear. As illustrated, each abrasive element 80 is provided on its inner surface with a plurality of spaced lands and grooves 82, which mate with corresponding lands and grooves 84 formed in the V-shaped recess 86 of the backing member 88. Preferably, a bond as described with reference to Figures 1, 2 and 3, is provided to adhere each abrasive element 80 to the associated backing member 88 in order to withstand the stresses on the abrasive element due to the roll of the gear and tool,

Figures 10 and 11 illustrate a construction similar in many respects to the construction described with reference to Figures 5, 6 and '7 in which the single rabbet 54 of Figures 5, 6 and 7 is replaced by a plurality of longitudinally extending serrations 90 formed in each abrasive element 92, and which mate with corresponding longitudinally extending serrations 94 formed in the associated backing member 96. End plates 98 secured to the backing members 96 by studs I are preferably provided to positively prevent relative longitudinal movement between the parts. As in the previously described embodiments, the union thus formed between the abrasive elements and the backing members may replace or supplement any adhesive bond formed therebetween.

In the embodiments of Figures 12 and 13, wedges are utilized to replace or supplement adhesive bonds between the abrasive elements and the backing members. In Figure 12, the abrasive elements III] are provided with V-shaped bases I [2 as described with reference to the other embodiments and in addition, are provided with longitudinally extending laterally disposed shoulders H4, against which the longitudinally extending locking strips H6 bear. The locking strips H6 may be secured to the tool structure in various ways, as by side bars I24 which engage the hooked ends of the strips. In Figure 13, the shoulders H4 and locking strips H6 of Figure 12 are dispensed with and are replaced by V-shaped wedge members H8, the tapered sides of which mate with and bear against the corresponding tapered sides of the abrasive elements I20 and thus positively force the latter into engagement with the backing members I22.

In each of the foregoing embodiments, it will be observed that each tool tooth is of composite construction, embodying an abrasive element and a metallic backing member, which are suitably bonded together. The use of the solid abrasive sticks effectively overcome any difiiculties heretofore encountered through application of abrasive layers to the tooth portions of the rack or tool blades. The combination of the abrasive sticks with the metallic backing members effectively overcomes any difiiculty which might otherwise be encountered due to the substantial compressive force to which it is necessary to subject the blades by the securing bolt 28, to hold the blades in proper relative position. The resulting tool is accordingly highly effective and satisfactory in operation and as will be evident from the simple construction of the elements thereof, may be relatively economically produced.

In practice, it will be appreciated that the expected duty of the tool will determine whether the abrasive elements and the backing members are to be secured together entirely by an adhesive bond, or whether mechanical anchoring means will be provided between the abrasive elements and backing members. The same considerations will also determine whether the mechanical or adhesive bonds are to be used separately or in supplementary relation. The adhesive bond is advantageous in that it permits a simpler formation of the individual elements, while the mechanical bond is regarded as advisable for heavier duty application of the tool.

Although only a few embodiments of the present invention have been described in detail, it will be evident that various modifications in the form and arrangement of the parts of the illustrated embodiments may be made within the spirit of the present invention. The described embodiments, accordingly, are to be regarded in an illustrative and not in a limiting sense.

What is claimed is:

A tool for finishing gears or the like having a body portion and a plurality of teeth formed thereon, each of said teeth comprising a single abrasive element of a form conjugate to the teeth to be produced, each of said abrasive elements and said body portion having a plurality of mating serrations extending along the cooperating surfaces thereof to form an interlocking joint therebetween.

JOSEPH C. DRADER.