US643836A - Gearing. - Google Patents

Description

No. 643,836. Patented Feb. 20, I900.

H. c. .WARRE N. I

GEABING.

(Application filed Dec. 28, 1897.:

(No Model.) 3 Sheets-Sheet l,

mild

Witnesses: 1

Q Inventor: Herbert 6. Warren.

Nu. 643,836. Patented Feb; 20, I900.

H. C. WARREN.

GEARING.

(Appliatiou filed Dec. 23, 1897.) (No Model.) 3 Sheets-Sheet 2,

Witnesses: Inventor:

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Patented Feb. 2!], I900. v

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3 Sheets-Sheet 3.

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UNITED STATES PATENT OFFICE.

HERBERT C. WARREN, OF HARTFORD, CONNECTICUT, ASSIGNOR OF ONE- HALF' TO MOSES C. JOHNSON, OF SAME PLACE.

GEARING.

SPECIFICATION forming part of Letters Patent No. 643,836, dated February 20, 1900.

Application filed December 28, 1897. Serial No. 663,849. No model.)

To all whom it may concern:

Be it known that I, HERBERT C. WARREN, a citizen of the United States, residing in Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Gearing, of which the following is a specification.

This invention relates to gearing generally, but is shown applied to bevel-gearing adapted for connecting a driving and a driven member so mounted as to be subject toirregularities or inaccuracies in alinement; and more particularly the invention relates to a driving mechanism of a construction and organization especially adapting the same for use in a machine, vehicle, or other apparatus having a supporting-frame of a more or less flexible, vibratory, or elastic nature and in which the positions of the members of the driving mechanism are liable to be changed relatively to each other by the distortion, flexure, or springing action of said frameas, for instance, in the frame of a bicycle, tricycle, or a motor-Vehicle.

My invention may be utilized with material advantage in bicycles of that class in which the driving-wheel is rotated from the pedal-shaft through the medium of gearing and a connecting side shaft and in which it is customary to connect the driving-wheel and pedal-shaf t by means of bevel-gears attached one to each end of the side shaft and meshing one with a gear-wheel carried by the pedalshaft and the other with a gear-wheel carried by the driving-wheel. In this class of bicycles considerable difliculty has been experienced on account of accidental distortion and misalinement of the side shaft, which is generally caused by the elasticity or flexure of the frame and which action cramps or disarrangcs the gears, throws them out of true working position, and renders them incapable of effective operation.

It is one of the chief objects of my invention to provide a set of gears the construction of which will facilitate universal adjustment thereof and at the same time insure a true rolling contact between intermeshing teeth and also to provide a driving mechanism comprehending one or more sets of intermeshing gears constructed and organized to permit such adjustment and obviate the necessity of constructing the support for said driving mechanism with the high degree of accuracy now required in the manufacture of framing, such as bicycle-framing.

A further object of my invention is the provision of a bevel-gear the crowns or front faces of the teeth of which are curved longitudin ally and the side faces or flanks of which are of convex form, the bottoms of the spaces between the teeth of said gear being also curved longitudinally.

In the drawings accompanying and forming part of this specification, Figure l is a horizontal section of a portion of a bicycle, showing a driving mechanism embodying my improvements applied to the same, said section being taken in the dotted line a a, Fig. 2, intersecting the axes of the crank-shaft and driving-wheel. Fig. 2 is a side elevation of the parts illustrated in Fig. 1. Fig. 3 is alongitudinal section of the driving mechanism illustrated in Fig. 1 detached from its supportingframe, a portion of the connecting-shaft between the two trains of gears being broken away. Fig.4 is a diagrammatic View in crosssection of one form of gear embodying my invention illustrating the peculiar shape of the teeth. Fig. 5 is a front view drawn in projection with Fig. at of a portion of the gear illustrated in said Fig. 4. Fig. 6is a diagrammatic view illustrating in horizontal section two intermeshing gears and also representing by dotted lines two rectangularly-disposed conoids to which the crowns or front faces of the teeth of said gears conform, said figure also showing in dotted lines two relatively-large gears conforming to the same conoids. In this figure the arcs defining the curvature of-the crowns of the teeth of the two gears do not intersect at a common point. Fig. 7 is a crosssectional view of a gear embodying this invention, the outer faces of the diametricallyopposite teeth and the bottoms of the toothspaces of which are disposed in arcs which intersect at the axis and in the rear of the front face of said, gear. Fig. Sis a cross-sectional View similar to Fig. at of two intermeshing gears, showing in dotted lines two extreme positions of one gear relatively to the other gear. Fig. 9 is a side elevation, partially in section, of two intermeshing gears similar to those in Fig. 8 and indicating by dotted lines the adjustment of the teeth of one gear laterally of the longitudinal plane of the teeth of the other gear or an adjustment in a plane transverse to that indicated in Fig. 8. Fig. 10 is an enlarged sectional view taken on a line corresponding with the dotted lines I) b, Fig. 8, looking in the direction of the arrow and showing a portion of the intermeshing teeth of two gears and indicating by dotted lines a normal and two extreme oblique positions of the teeth of one gear relatively to two adjacent teeth of the other gear; and Fig. 11 is a cross-sectional view of a form of gear the outer faces of the teeth of which are concaved in the direction of the length thereof and showing a portion of a gear having convexed teeth intermesln ing with the concaved gear.

Similar characters of reference designate like parts in all the figures of the drawings.

In the drawings only the part of a supporting-frame is illustrated which is necessary to illustrate the application and mode of operation of the driving mechanism embodying my present improvements, said frame being shown as that of a bicycle, including a portion of the driving-wheel and the crank-shaft thereof.

The frame or carrier (designated in a general way by F) may be of any suitable construction and comprises a front or driving member supporting bracket B, a rear or driven member supporting-bracket B, and two side tubes or rear braces O and C, connecting said brackets.

The driving mechanism in the preferred construction and organization thereof (illustrated most clearly in Fig. 1) comprises in addition to its carrier F a driving member D, shown as a crank-shaft rotatably supported in the tubular front bracket B, and a driven member D, shown as the hub of a drivingwheel of a bicycle rotatably mounted on the rear bracket 13, which bracket fixedly connects the rear ends of the two tubes or braces C and C; an intermediate or side shaft E, extending through and rotatably mounted in one of the side tubes, as C; a train of gears (designated in a general way by G) operatively connecting the driving member and intermediate shaft, and a train of gears (designated in a general way by H) operativelyconnecting the intermediate shaft and the driven member.

As a means for actuating the driving member or crank shaft D the same is shown equipped with the usual pedal-cranks 2 and 3.

In the form thereof illustrated in Figs. 1 3 one of the train of gears, as G, comprises two intermeshing gears g and 9 one of which, as g, is fixed to the driving member D and owing to its peculiar formation may be termed a concaved gear, and the other of which, as 9 is fixed to the forward end of the side shaft E and owing to its peculiar construction may be termed a convexed gear. The other train of gears, as H, comprises two intermeshing gears h and 7L2, one of which, as h, is shown as an ordinary bevelgear fixed to the rear end of the side shaft E, and the other of which, as 7L2, is shown as a convexed gear fixed to the end of the driven member D, this latter gear 7L2 being substantially the same as the gear 9 of the train G. As shown in said Figs. 1 and 3, the bottoms of the interdental or tooth spaces h between the successive pairs of teeth in gear 71. are straight, and the crowns h of the teeth of the gear h are convex, the result being that the one gear may rock on the other gear. This construction may of course be reversed without departure from my invention, or, in other words, the bottom of each tooth-space may be formed convex and the crown of each intermeshing tooth straight, when the same result will be accomplished. Furthermore, the same result is accomplished by making both the crown of each tooth and the bottom of each tooth-space convex, as shown in Figs. 4, 5, 6, S, and 9, in which, as will be seen, the gears may rock upon each other on the pitchline, and ample clearance is therefore provided at the ends of the bottoms of the toothspaces and of the teeth in said spaces to enable said teeth to accomplish this purpose. (See dotted lines, Fig. 8.) One construction is therefore the obvious equivalent to the other; but a greater amount of clearance is provided when both the bottoms of the toothspaces and the crowns of the teeth are of convex contour, as illustrated in said Fig. 8.

In the form thereof illustrated in Figs. 6 and 8 of the drawings the front face or crown 4 of each tooth is curved in the direction of its length, and the opposing side faces 5 and 6 are also curved in the direction of their lengths, the crowns or front faces of diametrically-opposite teeth being preferably disposed in arcs which are eccentric to any common point on the geometrical axis of the gear and the planes of which arcs intersect each other at a point on said axis. Each tooth has reentrant curved opposite side faces 5 and 6 tangent to the tooth-face angle indicated by dotted lines in Fig. 10, said side faces being convexed relatively to each other, or, in other words, the opposite ends of each tooth are reduced in width relatively to what would be the normal width of the tooth to furnish clearance-spaces, as 8, between the side faces of said tooth and the adjacent side faces of similarly-formed teeth at opposite sides, respectively, of said tooth to thereby facilitate lateral adjustment of the tooth of one gear relatively to the adjacent teeth of an intermeshing gear, as will be readily understood by reference to Figs. 9 and 10 of the drawings. For convenience the teeth of one gear are designated byt and those of the intermeshing gear by t.

It will be evident that the curvature of the side faces of each tooth of the gear may be of greater or less radius, according to the requirements, it simply being desirable to relieve the tooth at opposite ends sufficiently to permit a slight lateral movement of the intermeshing teeth of two gears relatively to one another.

In Fig. 10 one tooth of one gear is shown in full lines, having its curved opposite side faces in bearing contact with the adjacent faces of two teeth of the intermeshing gear at points substantially midway of the length of the said faces. The circle a; in this figure in'- dicates what might be considered the geometrical apex of the normal cones of both of said intermeshing gears, and the oblique lines 2' and j, radiating from said circle, represent, geometrically, the radial planes of the opposite side faces of a tooth and indicate, respectively, the normal relative angles of the side faces 5 and 6 of said tooth, the side faces of said tooth being tangent to said lines'i and j, and the points at which said lines touch the arc of the side faces indicating the points of contact between the side faces of one tooth and the adjacent side faces of two teeth of the intermeshin g gear.

In Fig. 8 of the drawings two intermeshing gears are shown in full lines in section in their normal or proper running positions relatively to each other, the dotted lines in said figure indicating two extreme positions of one gear relatively to the other gear when the shaft of said gear is shifted in the plane of the shaft of the other gear, so as to roll or adjust one gear upon the other in the direction of the length of the intermeshing teeth.

As will be observed, the sides or flanks of each tooth, as well as the crown thereof, are of convex form longitudinally, and the interdental spaces between the teeth also have longitudinally-convex bottom walls.

By providing two intermeshing gears the front faces of the teeth of which are curved in the direction of theirlengths I am enabled rection of the lengths of intermeshing teeth and at the same time preserve a proper mesh between said teeth, whereby to compensate for misalinement in the longitudinal axes of the two gears or a change in the relative angles of said axes in a plane common to both axes, and by providing intermeshing teeth with oppositely-curved opposing side faces I am enabled to secure a considerable range of adjustment of the axes of one gear relatively to that of the other gear in a plane transverse to the longitudinal lines of the teeth, or, in other words, secure an adjustment of the teeth of one gear laterally of intermeshing teeth of the other gear, and at the same time preserve a true rolling or operative contact between the side faces of intermeshing teeth.

From the foregoing it will be seen that a pair of intermeshing gears the teeth of which have their crowns or front faces curved in the direction of theirlengths and also have their opposite side faces or flanks likewise curved in the direction of their lengths a universal adjustment,- in the true meaning of the phrase, of said gears is facilitated, thereby compensating for any inaccuracies or irregularities in alinement or for changes in the relative angles in any direction of the shafts or axes of the two intermeshing gears-that is to say, two intermeshing gears constructed in accordance with my invention are not only capable of adjustment in the common plane of their axes, but are also capable of adjustment in a plane at right angles to said common plane without disturbing the true rolling or operative contact between intermeshing teeth, and any rattling or free play inci dental to gears having loose-fitting teeth will be obviated.

In Fig. 11 of the drawings and also in part in Figs. 1 and 3 I have illustrated one set of intermeshing gears the teeth of one gear of which have concaved front faces and the teeth of the intermeshing gear of which have convexed front faces, and the side faces of the teeth of the concaved gear will preferably be convexed, after the manner illustrated in Fig. 10, to provide for lateral adjustment of the teeth of one gear relatively to the intermeshing teeth of the other gear.

By reference to the several figures of the drawings it will be seen that while the teeth of the gears have their front and their side faces curved in the'direction of their lengths ICO the general forms of ordinary bevel-gear teeth duced width from a point near the middle portion of the length thereof toward the front end, although the rear end of the tooth is slightly reduced from what would be the normal width of a true bevel-gear tooth.

It is well known that with driving mechanisms wherein the frames are more or less elastic or liable to slight deflection the intermeshing gears of the driving mechanisms, if made with the usual coinciding surface on the gearteeth, must be maintained in a strictly-rigid position one relatively to the other to secure a proper rolling or operative contact, and, furthermore, on account of the elastic character of bicycle-frames it has been found impracticable tomaintain the gears in such a truly-rigid position as would secure the proper action of said gears. By means of my present improvements a proper action of the gears is maintained under any ordinary conditions, thus allowing for the necessary deflection of the frame, so that in practice a correct rolling action of the two surfaces will be maintained although the axes of the gears may be displaced laterally one relatively to the other to a very appreciable extent, and this is accomplished without the provision of such clearance between the teeth of gears as would create any objectionable play in the running of said gears.

Vhile my improved form of tooth is shown as embodied in a bevel-gear, it is distinctly to be understood that it is not limited thereto, it being applicable to gears of other kinds and also to racks which may have teeth of the form describedwithout departing from my invention.

I-Iaving described my invention, I claiin 1. A gear having the working faces or sides of its teeth convex longitudinallythereof, and having the bottoms of the spaces between each two teeth convex longitudinally thereof.

2. A gear having the working faces or sides of its teeth convex longitudinally thereof, the crowns of said teeth being also convex, and having the bottoms of the spaces between each two teeth convex longitudinally, substantially as and for the purpose specified.

A bevel-gear each tooth of which has a convex crown or top portion and convex side faces or flanks, the bottoms .of the interdental spaces between the teeth being so formed that when two gears are in mesh the teeth of one gear may rock longitudinally each at a point upon the oomplemental gear.

45. A bevel-gear having teeth of convex contour longitudinally both on the crown and on the flanks and provided with interdental spaces having convex bottoms, substantially as and for the purpose specified.

HERBERT O. WARREN. \Vitnesses:

HENRY BIssELL, EMORY C. WHITNEY.

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