CA1334369C

CA1334369C - Steering wheel tilt mechanism

Info

Publication number: CA1334369C
Application number: CA000616713A
Authority: CA
Inventors: Stephen Glenn Ritter
Original assignee: Deere and Co
Current assignee: Deere and Co
Priority date: 1988-07-29
Filing date: 1993-09-09
Publication date: 1995-02-14
Anticipated expiration: 2009-07-06
Also published as: CA1336105C; CA1335422C; CA1334368C; CA1334816C; CA1335421C

Abstract

A steering mechanism for a tractor includes a steering wheel mounted to a steering column that includes a universal joint. A pair of guide members are fixed on opposite sides an upper portion of the column between the steering wheel and universal joint and act to guide or restrain the upper portion of the column so that it moves fore-and-aft when pivoted about the universal joint. A releasable latch means is provided for latching the upper portion of the column in a desired position and includes latch element having tabs that are received in aligned gaps between a rack of teeth provided in each of guide members in a radius about a horizontal axis passing through the universal joint. Springs act to bias the latch element downwardly into the teeth and to bias a downwardly facing cam surface of the latch element into engagement with a complimentary shaped cam surface of a collar rotatably received on the column below the latch element. A latch release lever is connected to the collar for pivoting the same for effecting raising and release of the latch element through the interaction of the cam surfaces.

Description

i 334369 BTBBRING ~HBBL TILT ~U~NIBN
Related Application This is a divisional of Canadian application Serial Number 604,977 filed on 06 July 1989.
Background of the Invention The present invention relates to a steering system for a vehicle such as a lawn and garden tractor and more particularly relates to a steering wheel tilt mec-h~n;sm for use in such a system.
Tractors are known which are equipped with steering wheels that can be tilted to properly locate the steering wheel for easy manipulation by operators of different size.
However, these steering wheel tilt mechanisms are relatively complex.
Summary of the Invention According to the present invention, there is provided an improved steering wheel tilt mechanism and more specifically there is provided an improved tilt mec-h~n;sm for use with a steering column that is pivotable about an axis.
An object of the invention is to provide a steering wheel tilt mechanism which is of a reliable, relatively simple construction.
A more specific object of the invention is to provide a tilt mechanism, as discussed above, wherein a latch mechanism is mounted on the steering column and includes teeth releasably engaged with aligned sets of teeth provided in a pair of arcuate guide members located at opposite sides of the column about a radius emanating from the pivot axis of the column.
These and other objects will be apparent from a reading of the ensuing description together with the appended drawings.
Brief Description of the Drawing FIG. 1 is a left rear perspective view of a tractor, with parts shown in phantom lines, embodying a steering system with which the steering wheel tilt mechanism of the present invention is particularly adapted for use.

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1 334369 `
~ FIG. 2 is an exploded view of the parts comprising the tiltable steering wheel mechanism.
Description of the Preferred Embodiment Referring now to FIG. 1, therein is shown a lawn and garden tractor 20 including a longitudinal main frame 22. The frame 22 is supported on a pair of front steerable wheels, of which only the left wheel 32 is shown, and a pair of rear drive wheels, of which only the left wheel 46 is shown. The tractor 20 includes an engine (not shown) mounted to a forward portion of the frame 22 and enclosed by a hood. A combined operator station and fender structure 68 is mounted over a rear portion of the frame 22 and an operator seat 76 is located thereon so as to place a seated operator in reach of various tractor controls including a steering wheel 38 that is linked for steering the front wheels in a manner described below.
An axle 28 is mounted to a forward central location of the frame 22 for swinging about a fore-and-aft axis and has upright cylindrical receptacles 174 at its opposite ends. The pair of steerable front wheels are respectively mounted to a pair of L-shaped spindles 176 having upright portions swivelly received in the receptacles 174. Left and right arms 180 and 181 are respectively fixed to the respective upright portions of the spindles 176 at locations below the receptacles 174, the arms 180 and 181 being interconnected by a tie rod 184 and limited in their turning movement by stop blocks 249 fixed to the underside of the axle 28. A steering control arm 186 is fixed to an upper end of the upright portion of the left spindle 176. A drag link 190 has its forward end connected to the arm 186 by a ball joint connector 191 and has its rearward end connected to a lower end of a pitman arm 192 having its upper end fixed, as at 246, to an output shaft of a conventional steering gear box 188. An input shaft 194 extends into the gear box 188 and has an upper end universally coupled, as at 198, to a lower end of a steering column 200 having the steering wheel 38 fixed to the upper end thereof.
It will be appreciated then that steering is accomplished in t 33~36~
the usual way`by turning the steering wheel 38 one way or the other for steering the wheels within a range of movement determined by the stop blocks 249, with lock-to-lock movement of the steering wheel corresponding to that for moving the wheels between maximum right- and left-turn positions.
Referring now also to FIG. 2, therein is shown a steering wheel tilt mechanism 204 which includes a series of elements received on the column 200. Specifically, a support collar 225 is fixed to the column at a preselected distance from the lo top of the column. Resting on the collar 225 is a cylindrical spacer 224 and resting on the spacer is a sleeve 210 having an enlarged lower end defining an upwardly directed ramp or cam surface 211. A collar-like latch element 212 is received over a top portion of the sleeve 210 and includes a ramp surface (not shown) on its lower surface which is complimentary to and rests against the surface 211 so that counterclockwise rotation of the sleeve 210 causes the latch element 212 to shift upwardly. Right and left substantially arcuate position guides 214 and 215 are bolted together in fixed parallel relationship and are rigidly mounted to a dash support (not shown) so as to be on opposite sides of the sleeve 210. Each of the guides 214 and 215 includes a rack of teeth 220 having notches 218 therebetween with the teeth being arranged arcuately about a horizontal transverse axis passing through the universal joint 198 of the steering column 200 (FIG. 1).
The latch element 212 includes a pair of downwardly projecting lugs 222 (only one shown) releasably received in a selected transversely aligned set of the notches 218. A pair of springs 228 (only one shown) have upper ends bent into a hook received in an aperture of a respective one of oppositely projecting ears of the latch element 212 and lower ends bent into a hook received in a respective aperture of a fixed support (not shown) so that they act to bias the latch element against the cam surface 211 of the sleeve 210 and to releasably retain the lugs 222 in the notches 218. The latch element 212 also includes a pair of downwardly projecting tabs 223 that extend between and cooperate with facing flat -surfaces of the guide members 214 and 215 to restrain the column 200 from tilting sideways at the universal joint 198.
A latch release lever 206 includes a sleeve received on the upper end of the column 200 and over the upper portion of the sleeve 210. The sleeve of the lever 206 is provided with diametrically opposite, longitudinally extending indentations (only one shown) that are drivingly engaged with diametrically opposite axially extending notches provided in the upper end of the sleeve 210. A flexible dust cover or boot 208 is received over the column 200 beneath the lever 206 and includes a lower rectangular end that is adapted for being inserted in a rectangular opening provided in a dash (not shown) and releasably engaged with a rectangular edge of the dash delineating the opening.
Adjustment of the tilt of the steering wheel 38 can thus be accomplished by rotating the lever 206 downwardly or counterclockwise, as viewed in FIG. 2, to effect raising of the latch element 212 so as to withdraw the lugs 222 from a given set of the notches 218. The steering wheel 38 together with the column 200 is then adjusted to a desired new angular position relative to the universal joint 198. The lever 206 is then released and returned to its upward position whereupon the springs 228 act to shift the latch element 212 downwardly to engage the lugs 222 with a new set of the notches 218.
It is noted that the tilt mechanism 204 may be omitted, if desired, in which case a rectangular retainer 230 is placed over the column 200 and fixedly positioned in the rectangular dash opening so as to hold the column in a fixed position.

Claims

1. In a steering wheel tilt mechanism for a steerable vehicle including an upright steering column carrying a steering wheel at its upper end and being mounted for pivoting fore-and-aft about a horizontal pivot axis, a pair of transversely spaced column guide members having the column located therebetween, a member carried by said column for slidably engaging said guide members, a rack of teeth formed in each of said guide members on a radius about said pivot axis and a latch member slidably mounted on said column and being releasably biased into engagement with selected gaps between the teeth so as to retain the column and thus said steering wheel in a selected attitude, the improvement comprising: said latch member also forming said member slidably engaging said guide members.

2. The steering wheel tilt mechanism defined in claim 1 wherein said latch member is in the form of a collar having an axially downwardly directed cam means defined on the bottom thereof; a sleeve rotatably mounted on but being fixed from shifting axially downwardly on the column below said collar and having an axially upwardly directed cam means shaped complimentary to and engaged with said downwardly directed cam means, with said upwardly and downwardly directed cam means acting for effecting axial upward shifting of the latch member upon the sleeve being rotated from a normal position; and a lever being mounted on said column for pivoting thereabout and including means connecting the same to said sleeve for effecting rotation thereof whereby said lever may be selectively rotated for effecting disengagement of the latch member from said teeth for permitting the steering wheel to be repositioned by pivoting said column about said axis.

3. The steering wheel tilt mechanism defined in claim 2 and further including spring means coupled between said collar and sleeve and biasing said cam means of the collar and sleeve together.