Steering Mechanism
A steering lever mechanism for a mower vehicle includes a lever assembly and a base which is fixed to the mower vehicle for mounting the lever assembly to the mower. The lever assembly includes a pivot assembly and a lever portion. The lever portion is pivotably mounted to the pivot assembly for rotation about a longitudinal axis between an inboard position and an outboard position. The pivot assembly is also pivotably mounted to the base for rotation of the pivot bracket portion and the lever portion about a transverse axis between a rear position, an intermediate neutral position and a forward position. A rotation-measuring device is associated with the base and the pivot assembly for measuring the forward and rear rotation of the lever assembly.
This application is a continuation of, and claims priority to, pending U.S. Nonprovisional application Ser. No. 14/621,745 filed Feb. 13, 2015, now (the “'745 application”). The '745 application is a continuation of U.S. Nonprovisional application Ser. No. 13/584,282 filed Aug. 13, 2012 (the “'282 Application”). The '282 application is a continuation-in-part of U.S. application Ser. No. 12/586,411 filed Sep. 22, 2009, now U.S. Pat. No. 8,240,420 (the “'411 application”). The '411 application claims the benefit of U.S. Provisional Application No. 61/197,199 filed Oct. 23, 2008. The entireties of the aforementioned applications are each incorporated herein by reference.
FIELDThe present invention relates to a steering mechanism for a riding lawn mower.
BACKGROUNDZero turn electric lawn mowers have been known in the art for several years. An example combined steering and brake control lever mechanism is taught by U.S. Pat. No. 6,729,115 issued to Bartel. The applicant's incorporate U.S. Pat. No. 6,729,115 herein as if repeated verbatim hereinafter. U.S. Pat. No. 6,729,115 teaches a mechanism which includes left and right steering levers. In the arrangement taught in U.S. Pat. No. 6,729,115 each of the steering levers independently control hydraulic valves which in turn control the flow of hydraulic fluid to one of either the left or right hydraulic drive wheel motors. Thus, in the steering control system taught in U.S. Pat. No. 6,729,115, if the operator pushes the right steering lever forward of the neutral position, the right drive wheel will rotate in a forward direction and if the operator pulls the right steering lever back from the neutral position, the right drive wheel will rotate in a reverse direction. The same is true for the left steering lever. Moreover, in the arrangement taught in U.S. Pat. No. 6,729,115, each steering lever may be pushed outboard when it is in the neutral position and if the operator pushes a steering lever outboard from the neutral position, a linkage is actuated to engage a parking brake associated with the wheel on the same side of the mower. The driving feel of the hydraulic based arrangement described in U.S. Pat. No. 6,729,115 has been well received by operators. The hydraulic valves of the arrangement described in U.S. Pat. No. 6,729,115 provide feedback resistance in response to steering lever movements. Also, in the arrangement taught in U.S. Pat. No. 6,729,115 the outward movement of a steering handle from the neutral position to engage a parking brake moves linkage members in a parking brake linkage which in turn provides mechanical resistance to the outward movement of the handle. If an electric steering interface is selected for accomplishing the general functions of the arrangement taught by U.S. Pat. No. 6,729,115, then the problem of providing feedback through the steering handles to the operator arises. What is needed is an electric zero turn radius (ZTR) steering and brake interface which provides substantially the same feel as the arrangement taught in U.S. Pat. No. 6,729,115.
BRIEF DESCRIPTION OF THE INVENTIONThe present invention answers this need by providing steering lever mechanism which includes a lever assembly and a base including at least one bracket fixed to the frame of the mower vehicle for mounting the lever assembly to a mower vehicle. The lever assembly includes a pivot assembly and a lever portion. The pivot assembly is pivotably mounted to the base for rotation of the pivot assembly and the lever portion about a transverse axis between a rear position, an intermediate neutral position and a forward position. A position-measuring device is associated with the base and the pivot assembly for measuring the forward and rear rotation of the lever assembly. A mechanical resistance device connects between pivot assembly and the frame of the mower vehicle for resisting rotation of the pivot assembly and the lever assembly between the forward position and the rear position. The lever portion is also pivotably mounted to the pivot assembly for rotation about a longitudinal axis between an inboard position and an outboard position. A sensor for activating a parking brake is also associated with the base for sensing the lever portion when it is in the outboard position. A cam member is fixed to the lever portion and has first and second recesses. A cam follower is pivotably mounted to the pivot assembly and is spring biased for engaging one of the first or second recesses of the cam member. The cam follower and the cam member are arranged such that the cam follower is urged into the first recess when the lever portion is in the inboard position and such that the cam follower is urged into the second recess when the lever portion is in the outboard position. At least one of the brackets of the base includes a slot which is located to receive the lever portion when the lever portion is in the neutral position (with respect to forward and backward rotation) as the lever portion rotates outboard. A stop member fixed to the base prevents the lever portion from rotating past the neutral outboard position. A sensor associated with the stop member produces a signal when the lever portion is in the neutral outboard position.
Referring to the drawings,
As can be best seen in
Pivot assembly 150 includes a pivot shaft 152 and a pivot bracket assembly 160. As is best shown in
Lever assembly 100 is pivotably mounted to pivot bracket assembly 160 so that when permitted by a transverse slot 22A located near the upper end of outboard bracket 22, lever assembly 100 can rotate about axis B shown in
As noted above, lower lever member 112 of lever assembly 100 is pivotably mounted to the upper end of pivot bracket assembly 160 for rotation about axis B shown in
Lever assembly 100 is fixed to pivot bracket assembly 160 when considered from the perspective of rotation about a transverse axis. However pivot bracket assembly 160 is mounted to brackets 22 and 24 by shaft 152 for rotation about a transverse axis A shown in
The rotation of lever assembly 100 and the rotation of pivot bracket assembly 160 about axis A is resisted by a dampener unit 400 which connects between the extreme lower end of pivot bracket assembly 160 and vehicle frame 2. In this example dampener unit 400 is a linear dampener which is adapted to resist the rotation of pivot bracket assembly 160 (and thus lever assembly 100) either in a forward or rear direction about axis A. In this example, dampener unit 400 preferably includes a compression spring 402 which is positioned within dampener unit 400 such that spring 402 biases lever assembly 100 away from the rear position and toward the neutral position. With this arrangement, the operator must apply constant pressure to cause the mower to move in reverse, yet, the operator merely moves lever assembly 100 to a forward position and holds lever assembly 100 in the selected forward position without applying constant pressure in order to cause the mower to move forward. In this example, dampener member 400 is pivotably connected to frame 2 at its distal end and pivotably connected at its proximate end to a cylindrical lug 170 which is fixed to the lower end of pivot bracket assembly 160. Cylindrical lug 170 is spaced away form the axis of rotation A of pivot bracket assembly 160 so that rotation of pivot bracket assembly 160 about axis A causes displacement of the proximate end of dampener member 400 relative to the fixed distal end of dampener member 400.
It is to be understood that while certain forms of this invention have been illustrated and described, it is not limited thereto, except in so far as such limitations are included in the following claims and allowable equivalents thereof
Claims
1. An electric zero turn radius (“ZTR”) vehicle having a vehicle frame and right and left drive wheels that are each powered by a respective left or right drive wheel motor, a steering mechanism, and a parking brake mechanism, the steering mechanism comprising:
- a pair of control lever assemblies including a right control lever assembly for controlling the right drive wheel motor and a left control lever assembly for controlling the left drive wheel motor, each control lever assembly including, (1) a pivot bracket assembly which is pivotably mounted to the frame of the electric ZTR vehicle for rotation about a first axis between a first position, through a neutral position and a second position, wherein the pivot bracket assembly has an outboard side and an opposite inboard side, and (2) a position measurement device operably associated with the vehicle frame and the inboard side of the pivot bracket assembly by a shaft extending transverse between the vehicle frame and the pivot bracket assembly, the position measurement device is operable to measure the rotation or displacement of the pivot bracket assembly with respect to the vehicle frame in relation to the first position and the second position, the position measurement device being able to provide signals for controlling the direction of rotation and speed of rotation of said one of the drive wheel motors.
2. The electric ZTR vehicle of claim 1, wherein each control lever assembly further comprises a dampener unit connecting between the pivot bracket assembly and the vehicle frame suitable for resisting the movement of the pivot bracket assembly.
3. The electric ZTR vehicle of claim 2, wherein the dampener unit further includes a spring for biasing the pivot bracket assembly toward the neutral position.
4. The electric ZTR vehicle of claim 1, wherein each control lever assembly further comprises a lever assembly pivotably mounted to the pivot bracket assembly for rotation with respect to the pivot bracket assembly about a second axis between a first inboard position and a second outboard position.
5. The electric ZTR vehicle of claim 4, wherein the lever assembly is interconnected with the parking brake mechanism such that moving the lever assembly to the second outboard position sets the parking brake.
6. The electric ZTR vehicle of claim 1, wherein the steering lever mechanism further comprises at least one sensor associated with at least one of the control lever assemblies for detecting when the at least one control lever assembly is in the second outboard position.
7. The electric ZTR vehicle of claim 1 further comprising a drive control system capable to determine the direction of rotation and the speed of rotation of said one of the drive wheel motors from the position measurement device provided signals.
8. An electric zero turn radius (“ZTR”) vehicle having a vehicle frame and right and left drive wheels that are each powered by a respective left or right drive wheel motor, a steering mechanism, and a parking brake mechanism, the steering mechanism comprising:
- a pair of control lever assemblies including a right control lever assembly for controlling the right drive wheel motor and a left control lever assembly for controlling the left drive wheel motor, each control lever assembly including, (1) a pivot bracket assembly which is pivotably mounted to the frame of the electric ZTR vehicle for rotation about a first axis between a first position, through a neutral position and a second position, wherein the pivot bracket assembly has an outboard side and an opposite inboard side, (2) a lever portion which is pivotally mounted to the pivot bracket assembly for rotation with respect to the pivot bracket assembly about a second axis between a first inboard position and a second outboard position, and (3) a position measurement device operably associated with the vehicle frame by a shaft extending transverse between the vehicle frame and the pivot bracket assembly, the position measurement device is operable to measure the rotation or displacement of the pivot bracket assembly with respect to the vehicle frame in relation to the first position and the second position, the position measurement device being able to provide signals for controlling the direction of rotation and speed of rotation of said one of the drive wheel motors.
9. The electric ZTR vehicle of claim 8, wherein the first axis is orthogonal to the second axis.
10. The electric ZTR vehicle of claim 9, wherein the second axis is vertically offset from the first axis.
11. The electric ZTR vehicle of claim 8, wherein the pivot bracket assembly is in the neutral position when the lever portion is in the first inboard position.
12. The electric ZTR vehicle of claim 8, wherein the position measurement device is operably associated with the vehicle frame and the inboard side of the pivot bracket assembly.
13. The electric ZTR vehicle of claim 8, wherein the position measurement device is operably associated with the vehicle frame and the outboard side of the pivot bracket assembly.
14. The electric ZTR vehicle of claim 8, wherein the lever portion further comprises:
- a lower member having an upper end and a lower end, the lower member pivotally mounted to the pivot bracket assembly between the upper end and the lower end; and
- a brake linkage operatively coupled to the lower end of the lower member for engagement of a parking brake and disengagement of the parking brake, wherein the parking brake is engaged when the lever portion is in the second outboard position and the parking brake is disengaged when the lever portion is in the first inboard position.
15. The electric ZTR vehicle of claim 14 further comprising:
- the pivotal mounting between the lower member and the pivot bracket assembly being spaced a first distance above the first axis; and
- the lower member extending from the pivotal mounting to the lower end a second distance, wherein the second distance is greater than the first distance.
16. The electric ZTR vehicle of claim 14, wherein the brake linkage further comprises:
- a lever coupled proximate the lower end of the lower member, the lever extending to and coupled with a brake pivot plate;
- the brake pivot plate pivotally mounted to the frame;
- a connecting rod coupled to the brake pivot plate, the connecting rod extending to and coupled with a brake bracket, the brake bracket configured to set the parking brake upon actuation of the brake linkage.
17. The electric ZTR vehicle of claim 14 further comprising a handle is fixed to the upper end of the lower member.
Type: Application
Filed: Apr 19, 2021
Publication Date: Aug 5, 2021
Inventors: Harlan John Bartel (North Newton, KS), Brian Roy Funk (Lehigh, KS)
Application Number: 17/233,653