Adjustable wheel bracket assembly

[57] ABSTRACT

An adjustable wheel bracket assembly which includes a relatively stiff wheel axle crank and a relatively flexible spring steel adjusting lever keyed to the crank is provided with tension producing mechanism to take up the tolerance and eliminate play in the assembly. The tension producing mechanism comprises a warp formed in the spring steel lever and a clamp to exert pressure on the warp and thus create tension in the system to hold the assembly together without play.

Claims, 6 Drawing Figures

UNITED STATES PATENTS

2,503,884 4/1950 Noble et al.

.............................29/526

<img file="US3649828A_D0001.tif" />

PATENTEDMar14 1972

3,649,828

SHEET 1 OF 2

<img file="US3649828A_D0002.tif" />

PATENTEDMAR14 1972

3,649,828

SHEET 2 OF 2

<img file="US3649828A_D0003.tif" />

3,649,828

ADJUSTABLE WHEEL BRACKET ASSEMBLY

BACKGROUND OF THE INVENTION

An adjustable wheel bracket having a crank for an eccentrically mounted wheel and a spring lever by which the crank is adjusted is generally old. However, in prior devices of this type, considerable play develops between the crank and the spring lever, both because of manufacturing tolerances in part size and because of wear which develops during use. Conventional means for eliminating play, such as a wave washer between parts, have not proven satisfactory.

SUMMARY OF THE INVENTION

According to the present invention, play is eliminated between the parts without the need to resort to wave washers or other extraneous and additional elements. The spring lever is provided with a warp, such as a conical offset, near the inner end of the lever where it engages the crank. The lever and crank are embraced by a clamp by which axial pressure is exerted against the warp, thus to tension the warp and press the lever against the crank. This tension or spring bias eliminates play and takes up tolerances in the assembly.

Other objects, features, and advantages of the invention will appear from the disclosure.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view on a reduced scale of a rotary mower which is typical example of a wheeled device to which the invention is applicable.

FIG. 2 is a side elevation of an adjustable wheel bracket assembly embodying the invention.

FIG. 3 is a vertical cross section taken along the line 3—3 of FIG. 2.

FIG. 4 is an exploded perspective view of the wheel crank, spring lever, clamp bushing and clamp bolt.

FIG. 5 is an enlarged cross section of the hub portion of the assembly prior to exerting clamping pressure on the shouldered bushing.

FIG. 6 is a cross section similar to that shown in FIG. 5, but showing the parts after clamping pressure is exerted on the bushing.

DESCRIPTION OF PREFERRED EMBODIMENTS

Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. The scope of the invention is defined in the claims appended hereto. 1

The adjustable wheel bracket assembly of the present invention is typically applied to each of the four wheels 10 of the rotary mower shown in FIG. 1. The assembly 12 comprises a backup plate 13 which is mounted fixedly to the skirt 11 of the mower deck, as shown in FIG. 3.

The deck skirt 11 typically has an opening 14 through which a tang 15 on the backup plate 13 projects, thus to key the backup plate 13 in secure proper position with respect to the skirt deck 11.

The backup plate 13 is provided with a series of concentric bosses, namely, an inner boss 16, an intermediate boss 17, and an outer boss 18. These bosses face the swingable parts of the assembly, for purposes to be hereinafter described.

The vehicle wheel 10 is mounted on a stub axle 21 which projects laterally from the outer end of a swingable crank 22. ⁶⁵Crank 22 is made of stiff, heavy gauge steel, with an oblique intermediate portion 20. The inner end of crank 22 has a central opening 23 and peripheral locking lugs 24. The locking lugs 24 engage in corresponding locking apertures 25 near the inner end of a spring steel lever 26. Lever 26 is relatively flexi- ⁷⁰ble and has a handle 29 at its outer end. At its inner end lever 26 has an opening 27 of substantially the same size as the opening 23 in crank 22.

The engagement of the crank lugs 24 in the lever apertures couple the crank 22 and lever 26 so that these parts may be swung as a unit about the axis of a mounting bolt 28 on which the parts are mounted to the backup plate 13 and deck skirt

11, as shown in FIG. 3.

A bushing 31 shouldered at 33 (see FIG. 4) supports the assembled crank 22 and spring lever 26 on the mounting bolt 28. The end face 32 of bushing 31 seats against the boss 16 of backup plate 13 and bushing shoulder 33 seats against the inner end of the lever 26. When the parts are assembled, as shown in FIGS. 3, 5 and 6, the inner ends of the crank 22 and the lever 26 are embraced between the shoulder 33 on the bushing 31 and the boss 17 of the backup plate 13.

According to the present invention, the lever 26 is provided about its opening 27 with a conical offset or warp 35. Warp 35 is of sufficient depth of offset so that when the inner ends of the crank 22 and the lever 26 are placed into face contact prior to tightening the clamp bolt 28, as shown in FIG. 5, the spacing X between the crank 22 and the bottom of the warp 35 will be on the order of 0.030-0.040 inch. In the FIG. 5 position of the parts, there will also be a spacing indicated at “Z” in FIG. 5 between the end face 32 of the bushing 31 and the boss 16 of the backup plate 13.

Clamping pressure is developed on the warp 35 by the mounting bolt 28 and bushing 31. Clamp bolt 28 has its head 36 engaged with the bushing 31 and has a nut 37 engaged with washers 40, 41 which intervene between the nut 37 and the inner surface of the deck skirt 11.

When clamp bolt 28 is tightened, it draws bushing 31 toward the backup plate 13, thus to bottom the end face 32 of bushing 31 against the boss 16, as shown in FIG. 6. At the same time, bushing shoulder 33 draws the lever warp 35 toward the crank 22, against the tension of the spring steel of which the lever is formed. Thus the warp 35 is reduced in depth and the spacing between the warp bottom and the crank 22 is reduced to the spacing “Y” indicated in FIG. 6. Spacing “Y” is typically in the range of 0.015-0.020 inch.

In the course of tightening bolt 28, the warp 35 is stressed to produce tension in the assembly, thus to spring bias the parts together and take up tolerances in the apparatus and eliminate play between the parts.

As is conventional, the height of the wheel 10 is adjusted by springing flexible lever 27 to its broken-line position shown in FIG. 3 and swinging the lever and crank about the axis of mounting bolt 28. This action swings wheel axle 21 to a higher or lower position with respect to ground. Lever 26 is held in any selected position by one or another of the detents 42 which project from plate 13 and which selectively engage in the detent opening 43 in the lever 26.