US1734188A - Means for keying shafts to hubs - Google Patents

Description

Nov. 5, 1929.

' W. G. WIL SON MEANS FOR KEYING SHAFTS T0 HUBS Filed April 26, 1926 INVENTOR.

- W fie arr/r5 ynM KM ATTORNEYJ.

Patented Nov. 5, 1929 TUETED res WYLIE G. WILSON, OF JERSEY CITY, NEW JERSEY, ASSIGNOR TO WILSON RINGS COIVIPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY MEANS non KEYING sHArrs onnes Application filed April 26,

This invention relates to means for keying a hub to a shaft by means of a key of specified form and characteristics, which said key is operated on by forces adapted to put the same under cross-axial compression within suitable keyways. V

The invention also embodies certain discoveries with reference to the operation of the different materials referred to, and which materials are hereinafter classified as obdurate materials. The invention further embodies certain discoveries relating to mechanical movements inherent in the stressing of the cruciform bar to form the seal or lock.

have discovered that a bar thus formed will function with maximum efficiency for the purposes for which it is intended, when said bar is made of materials which, for the purpose of this invention, are termed obdu-rate materials. By this term is meant materials which are bendable, but not easily bent, compressible, but not easily compressed, elastic, but not easily deformed. As examples of obdurate materials, I may mention, without excluding others, iron, steel, hard alloys (such as bronze), glass, ceramic materials, hard rubber, and wood.

The obdurate materials, when employed pursuant to this invention, are operable within their elastic limit. By this I mean that, when embodied in a bar of cruciform cross section and placed under stresses which tend to deform the bar to decrease its transverse dimension in one direction, and increase its transverse dimension in the other direction, the bar shall retain a positive tendency to resume its original form when the stresses are relieved.

I have discovered that, if an X shaped bar of obdurate material is placed under transverse compression, which tends to decrease its transverse dimension in one direction, its transverse dimension in the other direction will be increased. If this stressing opera tion is carried out within a confined space or cavity, formed, e. g., by juxtaposing the keyways of a hub and shaft, the compression of the bar in one transverse direction will cause an expansion of the bar in the other transverse direction into locking engagement with 1926. Serial No. 104,677.

the walls of the cavity. This operation is availed of to render that portion of the cavity formed in the shaft (the keyway of the shaft) rigid with respect to that portion of the cavity formed in the hub (keyway of the hub) and when these respective portions of the cavity are rigid with respect to one another,

it follows that the hub is locked with respect to the shaft.

Attention is particularly directed to the fact that the stressing of the bar, as described, must be within the elastic limit thereof; otherwise the bar would not tend to resume (i. e., tend to spring back to) its normal form. Only a bar in the sense of this invention, composed of obdurate material and of substantially cruciform cross section, will thus properly function.

The term elastic limit, as employed in the specification and claims of this application, is so used to designate that quality or characteristic of the cruciform bar ofthe 0bdurat-e material employed, which, when compressed within predetermined limits, and then relieved of such compression, will cause the bar to return to approximately its origi-' nal form and size. It is intended that such compression shall be within, and not beyond, the tendency of the bar to return toits original form and size. That is to say, it is intended that the degree of pressure employed-shall notbe suflicient to break down and destroy the resilient or reactivequality of the cruci form section herein described. On the contrary, it is the purpose in practising this invention, that the degree of compression em-, ployed shall be limited to a degree where such resilient characteristics of said bar will not be seriously affected. V

For a better understanding of the operation of the X shaped bar of this invention,- it is suggested that it functions like a toggle. This analogy is of course not absolute, butwhen considered in that light, it may be helpful to a clearer conception of the operation of the invention. WVhen force is applied to the elbow of a toggle, a greater force is eX- erted at the ends of the toggle links, and this force increases in proportion as the axial dimension of the toggle, relative to the distance between the ends of the links, becomes less and less.

The bar of this-invention may be considered as functioning like a multiplicity of toggles; that is to say, there is a multiple toggle action in the cross section of the bar. When the bar is compressed transversely in one direction, the dimensions of the bar and the proportion of the obdurate material of which it is composed, bring about, within the bar, the steadily increasing functional characteristics incident to toggle action. This action results in the expansion of the bar in the other transverse direction, whereby two ofthe opposite sides of the bar are forced into locking engagement with the cooperating walls of the cavity in which it is positioned. The obdurate bar is so dimensioned and proportioned in its transverse section, that the lock or seal is effected in the manner described before the elastic limit of the bar is reached. Accordingly, upon release of the stresses incident to producing the lock or seal the bar tends to autogenously, i. e., automatically, break said lock or seal and become relatively loose in the cavity.

While the present invention is adapted for general application as a lock or seal, I have chosen, for concrete illustration, to describe it as used to secure a hub to a shaft. In thus practically carrying out the invention, the keyways of the shaft and hub to be secured together collectively constitute a cavity to receive the bar, which may be properly termed the key bar. Two of the opposite parallel walls of'the cavity are fixedly spaced apart, while the other two opposite parallel walls of the cavity are relatively adjustable by any suitable means provided for this purpose: Thekey bar is adapted to be slipped loosely into the cavity and thereafter the adjustable transverse dimension of the cavity is adapted to be decreased. .As a result of this decrease in one transverse direction of the cavity, the

- key bar is compressed in one direction to transversely stress it in the other direction, for the purpose of increasing its transverse dimension in the latter direction sufficiently to engage the opposite'sides of the key bar with'the walls of the cavity which are fixedly spaced. In this manner, the hub is tightly locked to the shaft.

The parts remain in this condition indefinitely, since the key is, while in locking condition, under the locking compression to which I have referred. However, when it is desired to remove the key bar, an increase of the adjustable dimension of the cavity, to relieve the key bar of compression, will bring about, within the key bar, an autogenous return of the bar to unstressed neutral condition, by which operation the key bar will be rendered sufliciently loose to permit it to be readily withdrawn from the keyways.

In practice, the parts are so proportioned that the key bar may be readily moved into and out of cooperative relation with the keyways without binding, but the fit between the teristic of the invention that when the locking.

stresses are relieved, the obdurate key will automatically, i. e., autogenously, tend to return to its original form; that is to say, for all practical purposes, it will return to its unstressed form, though not necessarily to absolutely the same form as it was prior to compression, for it may change slightly under compression.

An important feature of the present invention resides in the fact that the seal or lock of the present invention is repetitive. That is to say, it may be used over and over again which is not the case in the packings of the prior art, and, moreover, a tight lock or seal may be maintained indefinitely when employing the present invention.

I It is of further importance that the present invention may be economicallyconstructed and does not require refined workmanship in order to properly carry out its functions, since the form and material entering into the sealing or locking element is such that said element will, when stressed as described, properly conform to the surfaces of the space in whichit is used for the purpose of forming the lock or seal as may be desired.

Features of the invention, other than those Figure 2 is a section in the plane 2-2 of Figure 1 with the sealing and locking element shown in elevation.

Figure 3 is an end View of a sealing and locating element embodying this invention; an

Figure 4 is a plan view of such key.

For the purpose of illustrating this invention, I have shown. the same in the drawings as associated with a shaft and hub assembly in which 1 designates a shaft and 2 the hub of a pulley, fly wheel, gear or similar construction. The shaft is provided with a longitudinal keyway 3 and the hub is provided with a juxtaposed keyway 4.

The keyway 3 of the shaft has. three plane walls 5, 6 and 7. The wall 5 is perpendicular to a plane 22 which includes the axis of the shaft and bisects the keyway 3 longitudinally. The walls 6 and 7 are parallel to the plane 2-2, and perpendicular to the wall 5. It will be noted that these three walls 5, 6 and 7 bear fixed relation, each to the other.

The keyway 4 of the hub embodies part of a chamber 8 formed within the hub beneath a yoke 2 which spans the chamber and is pierced with tapped holes. Adjusting screws 9 extend through these holes and bear against a pressure plate or follower 10 positioned within the chamber 8. The pressure plate is of a size to have a close sliding fit with the walls of the chamber 8, as shown in Figure 1, and, as illustrated in Figure 2, is of a length substantially equal to the width of the hub.

The inner face or wall 11 of the follower constitutes the base of the keyway 4 of the hub and is perpendicular to the plane 2-2 and parallel to wall 5. The side walls of the keyway 4 are designated 12 and 13. They are parallel to each other and to the plane 2-2 and perpendicular to the wall 11.

When the keyways of the shaft and hub are juxtaposed, these two keyways, which are, in practice, of the same width, collectively form a cavity 14 having a fixed transverse dimension in a direction perpendicular to'the plane 22, while the radial dimension of such cavity is variable by movement of the pressure plate 10.

The key bar A of the present invention, which is adapted to be positioned within the cavity 14 to lock the hub to the shaft, is

, shown in detail in Figures 3 and 4. It is of a length substantially equal to the width of the hub 2 and of a, size adapting it to be received without binding into the cavity 14 when the screws 9 are retracted.

As shown in Figure 3, the key is of substantially X shape or cruciform cross section, with its opposite edges 1515 and 1616 in the form of plane parallel surfaces and its opposite edges 17 and 18 plane parallel surfaces, but perpendicular to the surfaces 15-15 and 1616. This bar is adapted to be introduced into the cavity 14 with the surfaces 15 and 16 juxtaposed with and parallel with the walls 12 and 13 of the hub keyway, and the surfaces 15 and 16 juxtaposed with the walls 6 and 7 of the shaft keyway, while the surfaces 17 are juxtaposed with the wall 11 of the follower and the surfaces 18 are juxtaposed with the base 5 of the shaft keyway. After the key bar has been placed in this position, the screws 9 are tightened for the purpose of forcing the follower in a direction radial to the shaft. This operation brings about a compression of the key bar between the surfaces 5 and 11. This results in a decrease of dimensions of the key shaft keyway and to simultaneously move its edges 15 and 16 into engagement with the walls 12 and 13, respectively, of the hub keyway. By thus stressing the key bar, the surfaces 15, 16, 15 and 16 are simultaneously brought into locking engagement with the cooperating walls of the keyways of the shaft and hub, for the purpose of firmly securing the hub to the shaft.

' So long as the parts are in locking condition, the key bar will remain in stressed condition. However, if the screws 9 are unscrewed to relieve the radial pressure on the key bar, the stresses to which I have referred will automatically, i. e., autogenously, efiect the shifting of the key bar into unstressed condition and will bring about, within the key bar, a return, at least in degree, toward its previously unstressed form.

As a result of this operation, the lock will be automatically broken and the key bar can be readily removed. The construction which I have described may be operated a great number of times and may thus be considered as repetitive. In other words, it is not necessary to provide a new key bar for each successive locking: operation.

Experience has shown that a hub and shaft may be efficiently and expeditiously locked together by the construction which I have described. An important advantage inherent in the use of such construction is' that absolute conformity of the key bar with the keyways of the respective parts results without requiring'careful fitting or machining. As

a matter of fact, the obdurate key bar will adapt itself to slight irregularities in the keyways and will therefore automatically lend itself to a tight lock throughout its extent.

When using the lock of the present invention, no difficulty is experienced in inserting,

or removing the key bar. This is in pronounced contradistinction to prior practice where the operation of inserting and removing properly fitted keys is laborious and time consuming. Under prior practice, it is not possible to slip the. key in loosely and have it function properly. If the key is loose under prior practice, it is worthlessandif'it is.

slipped into the keyways loosely, it will always remain loose. The key bar of the present invention is slipped loosely into position and,

when in place, is acted upon to produce a with the walls 6 and 7, respectively, of the tight fit, thus excluding thepossibility of movement between the key bar and its co- Operating keyways ofthe shaft and. hub. 7

The key bar, which I have described, is of pronounced practical value and-utility, not

only in forming looks, as between a shaft and. hub, but in various other environments, in which it is adapted for use. The tendency of the cruciform cross section, in a bar of obdurate material, to autogenously return, or tend to return, to its originalform, after compression, is of primary importance. As previously stated, this retraction does not necessarily involve a return of the bar to exactly the same form, but to approximately that same form, when considered from a practical standpoint. Such a tendency to return or spring back satisfies the practical requirements of the invention.

The resulting quality of the obdur'ate material from which the bar, is made, thus lends itself to repeated action and reaction through an extended period of operation in. any of the several arts or environs in which it is adapted for employment.

In the foregoing detailed description, I have set forth the invention in one of its practical forms, which will serve to give a clear understanding'of the invention and its mode of operation. Looking at the construction from a broad generic standpoint, it is apparent that the invention consists in housing a bar of obdurate material and of cruciform or X shaped cross section within'a space or cavity formed by the parts or members between which it is desired to form a seal or look. This cavity has relatively fixed dimensions in one direction and'variable dimension in the other direction. Thereupon the variable dimension of the cavityis decreased to place the bar under transverse compression in one direction for the purpose of expanding it in a perpendicular direction, whereby it is stressed, within its elastic limit, to bring two of its opposite sides into sealing or locking relation with the cooperating Walls of the cavity in which it is housed. Manifestly, the structure as described is adapted to'a wide.

.variety of uses in many arts where a seal or look is desired. For this reason, the invention is to be understood as not limited to use in shaft and hub assembly, but rather as intended for general application.

The foregoing detailed description sets forth the invention in its preferred practical? form, but the invention is to be understood as fully commensurate with the appended claim.

Having thus fully describedthe invention, what I claim as new and desire to secure by LettersPatent is: r

' ,Means for keying a hub to a shaft, which consists in a hub and shaft with oppositely -disposedkeyways ofright angular form in cross section, in combination with. a. key of compression is relieved. V

Signed by me at Jersey City, J., this- 'WYLIE. G. WILsoN.

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