Zero radius steering, compact stand-on mower and utility tractor

• US 6,185,920 B1
• Filed: 07/15/1999
• Issued: 02/13/2001
• Est. Priority Date: 07/20/1998
• Status: Expired due to Fees

• Current Assignee: Boneal, Incorporated
• Original Assignee: Lonmore Lc
• Inventors: Oxley, Lonnie
• Primary Examiner(s): PEZZUTO, ROBERT ERIC
• Application Number:
  US09/363,987
• Time in Patent Office: 579 Days
• Field of Search: 56/147, 56/172, 56/171, 56/154, 56D/IG.14, 280/164.1, 280/91, 280/99, 280/112.2, 180/24.01, 180/256, 180/124.103, 180/400, 180/409, 180/900, 362/52
• US Class Current: 56/14.7
• CPC Class Codes: A01D 2101/00 Lawn-mowers
• CPC Class Codes: A01D 34/66 with two or more cutters
• CPC Class Codes: B62D 51/008 characterised by the vehicle being formed by articulated or separable units road trains B62D53/00
• CPC Class Codes: B62D 51/02 the driver standing in the vehicle

Abstract

A self-propelled utility tractor having articulated steering, a standing operator, a turning radius near the rear wheel on the inside of a full turn, the radius of turn being not substantially longer than the wheel base, independent rear wheel brakes to assist in tight turns, a steering wheel for operating a steering linkage, an engine and transmission, centrally mounted with the engine below the transmission transmitting power by a jack shaft so the out put shaft of the engine extends down to power an attachment. Where the attachment is a mower deck, a rear discharge chute on the tractor deflects the clippings uniformly across the rear to avoid wind rowing. Flexible elements rotate above the mower blade to provide additional mulching and turbulent air flow and self-cleaning of the underside of the deck.

Claims

1. A self-propelled utility tractor comprising a frame having a front and rear providing an operator'"'"'s station, a steering wheel accessible from the operator'"'"'s station, a pair of drive wheels rotatably supported on the frame, one on each side, for propelling the tractor in forward or reverse directions, and at variable speeds, a pair of steerable wheels, steerable axles rotatable supporting a steerable wheel on the frame, one on each side, spaced longitudinally from the drive wheels, the axles mounted for articulation from a straight-ahead position to a full-lock right or left turning position, and a steering linkage mounted on the frame connected to the steerable axles and to the steering wheel for articulation of the steerable wheels relative to the frame, the geometry of which is such that the axes of each steerable axle intersect in a turning zone bounded longitudinally by 25 percent, and laterally by 20 percent, of the wheelbase length, bisected by the drive wheel axis of rotation on the inside of a turn whereby scuffing is minimized of the drive wheels in maximum turn conditions.

2. A self-propelled utility tractor as set forth in claim 1 wherein the steerable wheels are near the front, and the drive wheels near the repair of the frame, and the operator'"'"'s station is between the drive wheels to minimize the necessity of having to lean into a sharp turn.

3. A self-propelled utility tractor as set forth in claim 2 wherein the steerable axles supporting the steerable wheels are mounted on a pair of axle bars pivoted to the frame to allow independent oscillation of the steerable wheels.

4. A self-propelled utility tractor as set forth in claim 2 in which the steering linkage includes an actuator having rectilinear motion, either right or left, transversely of the frame adjacent the axle bars and parallel to them operated by the steering wheel, a pair of links one at each end of the actuator, and a pair of arms fixed to the steerable axles connected to the opposite ends of the links for rotating the steerable wheels, the dimensions being such that at full stroke of the actuator, right or left, the axes of the steerable wheels intersect near the center of rotation of the drive wheel on the inside of a turn.

5. A compact, self-propelled utility tractor comprising a frame supported on a pair of steerable wheels adjacent the front and a pair of driven wheels adjacent the rear, the longitudinal distance between the axes of rotation of the steerable and driven wheels defining a wheelbase, the lateral spacing of the wheels on opposite sides of the frame defining the track width, an operator'"'"'s station for a standing operator approximately mid-way between track width, a steering wheel accessible from the operator'"'"'s station, steering system supported on the frame including a steering linkage operated by the steering wheel, said steering linkage being connected to the front wheels which are capable of articulation about a steering radius, independent wheel brakes associated with each drive wheel accessible from the operator'"'"'s station for independently braking rotation of the drive wheel on the inside of a turn while the other continues under power to assist in making the turn, the wheel base equal to but not substantially greater than the track width, and the steering linkage being capable of articulating the front wheels at maximum turn so as to cause the steering radius to be substantially near the wheel on the inside of the turn of the tractor for maximum maneuverability and for working in tight quarters.

6. A compact, self-propelled utility tractor as set forth in claim 5 wherein spindle shafts rotatably support the front steerable wheels, an axle bar, one for each steerable wheel, mounting the spindle shafts, a pivot location on the centerline of the frame for each axle bar allotinng independent oscillations of the spindle shafts and front wheels, spindle arms fixed to each spindle shaft extending forwardly, a pair of links having outer and inner ends, one pivotally attached to each spindle arm on the outer end and the inner end extending inwardly toward the associated axle bar, an actuator in front of the axle bars capable of rectilinear motion closely parallel to the axle bars pivotally attached to the inner ends of the links whereby rectilinear motion of the actuator is translated into angular motion at the steerable wheels by the links and spindle arms, such that at full tun of the steering wheel, the actuator is stroked either right or left to cause the links and spindle arms to travel in an arc which is amplified by the geometry of the links and arms, whereby the axes of the spindle axles intersect near the axle end of the drive wheel on the inside of a full turn.

7. A compact, self-propelled utility tractor as set forth in claim 5 wherein a mower deck is underslung beneath the frame between the front and rear wheels adapting the tractor for mowing, the mower deck having a discharge chute, a baffle housing mounted on the frame adapted to receive the cuttings from the discharge chute, baffles in the housing defining longitudinally curved paths for receiving the discharged cuttings from the mower deck and distributing them uniformly across the back to avoid wind rowing.

8. A compact, self-propelled utility tractor as set forth in claim 7 wherein the mower deck has three rotary cutting blades, one rotating counter to the other two, a belt and pulley drive, means connecting the belt and pulley drive to the cutting blades and to the source of power of the tractor to drive the blades at cutting speeds for cutting grass, ducts around each blade for confining the air flow in a circular path and discharging it out the rear of the deck, and a baffle housing mounted on the frame of the tractor extending from the discharge opening from the deck between the rear drive wheels for distributing the clippings uniformly behind the tractor.

9. A compact, self-propelled utility tractor as set forth in claim 5 wherein the frame supports an engine having an output shaft extending down toward the lower part of the frame, a transmission above the engine having an input shaft extending upwardly toward the upper part of the frame, a jack shaft, and flexible drive elements connecting the output shaft from the engine to the input of the transmission, a pair of output shafts on opposite sides of the transmission selectively capable of being driven from neutral in either forward or reverse directions, a differential in the transmission, and a pair of flexible drive elements extending downwardly, one from each output shaft of the transmission, for powering the respective drive wheel on that side of the tractor at either forward or reverse speeds.