AU762561B2 - Rack and pinion steering arrangement for a riding lawnmower - Google Patents

Description

Our Ref:7630320 P/00/011 Regulation 3:2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): Address for Service: Invention Title: Murray, Inc.

219 Franklin Road Brentwood Tennessee 37027 United States of America DAVIES COLLISON CAVE Patent Trade Mark Attorneys Level 10, 10 Barrack Street SYDNEY NSW 2000 Rack and pinion steering arrangement for a riding lawnmower The following statement is a full description of this invention, including the best method of performing it known to me:- 5020 RACK AND PINION STEERING ARRANGEMENT FOR A RIDING LAWNMOWER BACKGROUND OF THE INVENTION [0001] This application claims the benefit of U.S. Provisional Application No.

60/224,404, filed August 10, 2000.

I. Field of the Invention [0002] The present invention relates to a rack and pinion steering arrangement incorporated in a riding lawnmower to provide a low turning radius for the lawnmower.

plate is displaced by a steering wheel-mounted pinion which engages serrations on a curved edge of the plate. When the pinion is rotated by the steering wheel, the plate is 2. Prior Art S[0003correspondingly pivoted about its mounting. A paiwnmower of dsteering links are pivotally connecteds one employing a steering plate which is pivotally mounted to the frame of the mower. The plate is displaced by a steering wheel-mounted pinion which engages serrations on a curved edge of the plate. When the pinion is rotated by the steering wheel, the plate is correspondingly pivoted about its mounting. A pair of drag links are pivotally connected to the steering plate. Each drag link is joined to a respective spindle arm which supports a wheel. Thus, when the steering wheel is turned, the pivotal movement of the steering plate is transmitted through the drag links to cause the wheels of the lawnmower to turn.

P:\WPDOCS\LMB\Tmny Smmon\Spificaions\763320 spwidom-17IO4/03 -2- According to the present invention there is provided a riding lawnmower steering arrangement, comprising: a lawnmower frame; a steering column supported by said frame, the steering column being provided with a steering wheel at one of its ends and a pinion at its opposite end; a member joined to the frame in a fixed position for supporting a rack movable rectilinearly relative to the fixed rack supporting member, said rack being joined to guide elements disposed within a channel formed in said member and extending in a direction transverse to a longitudinal axis of the frame, said rack being positioned in operational relationship with the pinion so as to move in response to rotation of the pinion as a result of turning the steering wheel; a pair of axles for supporting ground-engaging wheels, said axles being pivotable about substantially vertical axes; and a pair of drag links pivotally connected to opposite ends of the rack and to respective axles whereby when the rack is moved, the axles are pivoted to steer the lawnmower.

S* *e DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION [0007] Referring to the drawing, a riding lawnmnower frame member 10 is illustrated. Member 10 is formed in an inverted U-shape having side walls 12 and 14 joined by a web portion 16. The frame member is positioned along the longitudinal axis of the lawnmower. The main platform 18 of the lawrnower is partially illustrated in phantom lines.

[0008] A steering column support member 20 is secured to the top suriace of frame member 10. A steering column 22 passes through an opening 24 at the top of member 20 and an opening 26 in fr-ame member 10. Steering wheel 28 is secured to the upper end of steering column 22, and a pinion 30 is joined to the bottom of column 22.

Thus, when wheel 28 is turned, the pinion 30 turns in the same direction.

[0009] A steering arrangement support member 32 is joined to frame member by being fastened to side walls 12 and 14. Member 32 includes spaced side walls 34 and 36 which lie in vertical planes and a front wall 38 extending between the side wallIs.

Upper portions 40 and 42 of the respective side walls 34 and 3 6 project forwardly of wallI (0010] A box-shaped spindle arm support member 44 is secured to the outer surface of front wall 38. A pair of generally L-shaped spindle arms 46 and 48 are pivotally mounted at opposite ends of member 44. The lower ends of arms 46 and 48 are P:\WPDOCS\DYS\spmie\7630320 spc.dc-26 Februay 2003 -4horizontally disposed, and they project outwardly from member 44 so as to serve as axles for ground-engaging wheels 50 (only one of which is illustrated). The upper ends of arms 46 and 48 have secured thereto connecting links 52 and 54.

[0011] A rack supporting member 56 is connected to the side walls 12 and 14 of frame member 10 and to the upper portion of the front wall of the steering arrangement support member 32. Member 56 includes a horizontally disposed lower portion 58 having a channel 60 which is slotted in a direction transverse to the longitudinal axis of frame member 10. A rack 62, having a rear edge 64 formed to cooperate with pinion 30, is joined to the underside of the lower portion 58 of the rack supporting member 56 by fasteners 66 and 68 which pass through openings in the ends of respective drag links and 72, openings in rack 62 and the slot provided in channel 60 of the rack supporting member 56. This joinder is such that rack 62 is free to move in rectilinear fashion along the slot. To facilitate and guide such movement, wheels 74 and 76 are positioned within channel 60 and are joined to rack 62 by fasteners 78 and 80 passing through the wheels 74 and 76 and the slot in channel [0012] The free ends of drag links 70 and 72 are inserted within openings provided in the ends of the connecting links 52 and 54. These connections at the free ends of the drag 20 links 70 and 72 are pivotable. This permits operation of the steering arrangement in the manner now to be described.

[0013] When steering wheel 28 is turned, a corresponding rotation of pinion occurs. Since pinion 30 is meshed with edge 64 of rack 62, the rack is laterally displaced along channel 60 of rack supporting member 56 in the direction of the desired turn. Rack 62 carries drag links 70 and 72 in the same direction. As this occurs, the connecting links 52 and 54 are pivoted in the direction of the turn to cause the ground-engaging wheels to correspondingly turn.

[0014] With the arrangement just described, the direction of movement of the riding lawnmower can be changed with minimal effort and with a low turning radius.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as an acknowledgment or any form of suggestion that, that prior art forms part of the common general knowledge in Australia.

Claims (4)

1. A riding lawnmower steering arrangement, comprising: a lawnmower frame; a steering column supported by said frame, the steering column being provided with a steering wheel at one of its ends and a pinion at its opposite end; a member joined to the frame in a fixed position for supporting a rack movable rectilinearly relative to the fixed rack supporting member, said rack being joined to guide elements disposed within a channel formed in said member and extending in a direction transverse to a longitudinal axis of the frame, said rack being positioned in operational relationship with the pinion so as to move in response to rotation of the pinion as a result of turning the steering wheel; a pair of axles for supporting ground-engaging wheels, said axles being pivotable about substantially vertical axes; and a pair of drag links pivotally connected to opposite ends of the rack and to respective axles whereby when the rack is moved, the axles are pivoted to steer the lawnmower.

2. An arrangement according to claim 1, wherein said guide elements are guide wheels disposed within said channel. S 20

3. An arrangement according to claim 2, wherein said rack is disposed adjacent a surface of the rack supporting member opposite a surface of the member within which the channel is formed, the guide wheels being joined to the rack by connectors passing through a slot in said member which communicates with the channel.

4. A riding lawnmower steering arrangement substantially as hereinbefore described with reference to the accompanying drawings. 0 DATED this 7 th day of April, 2003 MURRAY, INC. By its Patent Attorneys 30 DAVIES COLLISON CAVE