WO1999014095A1

WO1999014095A1 - Steering wheel assembly

Info

Publication number: WO1999014095A1
Application number: PCT/US1998/018447
Authority: WO
Inventors: Charles M. Crowell, Jr.; Craig B. Kelley
Original assignee: Caterpillar Inc.
Priority date: 1997-09-16
Filing date: 1998-09-04
Publication date: 1999-03-25

Abstract

The present invention pertains to a steering wheel assembly (10) that incorporates the control mechanism (52) for at least one machine function on the steering wheel (12). The control mechanism (52) is positioned on a control lever (42) that is mounted on the steering wheel (12) for relative rotation with respect thereto. The control lever (42) may be maintained at a preselected orientation throughout the entire range of movement of the steering wheel (12).

Description

STEERING WHEEL ASSEMBLY

Technical Field

This invention relates to a steering wheel assembly and more particularly to a steering wheel assembly that incorporates one or more control functions of a machine in the structure of the steering wheel.

Background Art

In the operation of construction machines it has been a recent trend to develop steering systems that employ control devices other than a steering wheel . In some instances the steering wheel has been replaced with a lever control that is moveable in a transverse direction with respect to the machine to control the steering system of the machine . In doing so, the overall rotary motion previously required by the operator, is greatly reduced as is the operator fatigue. To enhance the operation of the machine even more, various machine controls, such as transmission controls have been incorporated into the lever and may be manipulated with the fingers of the hand that grasps the steering lever. While this type of steering control is known to work quite well on certain machines, it's application is primarily limited for use on larger machines whose operation is restricted to a job site and is operated in a capacity that requires a relatively high degree of maneuverabi1ity .

In order to incorporate the advantages of the steering systems of these larger machines into smaller machines that operate at higher speeds, possibly on a roadway, other steering wheel designs have been introduced that mount the transmission controls into the steering wheel. The steering wheel must be utilized with a steering system that requires a limited amount of steering wheel rotation to keep the transmission controls in an area that is accessible to an operator's hand when the steering wheel is at its maximum positions. While this design has also been known to work quite well, it sometimes requires the operator to adjust the position of his hand during certain maximum positions of the steering wheel since the position of the controls are fixed with respect to the steering wheel . This has been known to reduce the operator's comfort in these maximum positions.

The present invention is directed to overcoming one or more of the problems as set forth above .

Disclosure of the Invention

In one aspect of the present invention, a steering wheel assembly is provided for a machine.

The steering wheel is mounted on a support column that is defined by the machine, and rotates about a first axis that is defined by the support column, to control the direction of movement of the machine upon rotation thereof. A control lever is rotatably mounted to the steering wheel about a second axis for relative movement thereabout with respect to the steering wheel . A control mechanism is mounted on the control lever and is operably connected to at least one machine function for independent control thereof.

With a steering wheel assembly as set forth above, additional machine controls such as transmission controls, may be incorporated into the steering wheel . Because the control lever is rotatably mounted to the steering wheel it will move with respect to the steering wheel as the steering wheel is rotated. In doing so, the hand with which an operator grasps the control lever is maintained at approximately the same orientation throughout the movement of the steering wheel . This provides an operator convenient access to the auxiliary controls mounted on the control lever while at the same time maintaining a comfortable wrist position.

Brief Description of the Drawings

Fig. 1 is a diagrammatic isometric view of a steering wheel assembly that embodies the principles of the present invention; Fig. 2 is a diagrammatic top view of the steering wheel assembly shown in Fig. 1; and

Fig. 3 is a diagrammatic view of the control lever taken along lines 3-3 of Fig. 2.

Best Mode for Carrying Out the Invention

Referring now to the drawings, it can be seen that a steering wheel assembly 10 is shown. The steering wheel assembly includes a steering wheel 12 that defines a curvilinear portion 14 and a substantially planar portion 16. The curvilinear portion is shaped substantially in a semi-circular pattern and terminates at a pair of end portions 18 and 20. Likewise, the planar portion 16 defines a first end portion 22 that is joined to the first end portion 18 of the curvilinear portion 14 at a first junction 24 and a second end portion 26 that is joined to the second end portion 20 curvilinear portion 14 at a second junction 28. The first junction 24 defines an angled portion that provides a smooth transition between the respective end portions 18 and 22. Likewise, the second junction 28 defines an angled portion, however it also defines a bore 30 that extends entirely through the steering wheel 12. A hub member 32 is interposed along the length of the planar portion 16 and is positioned substantially along the mid portion thereof. The hub member defines a bore 34 that receives and end portion of a steering column 36 and is rotatably mounted thereto about a first axis 37 to control the steering system of a machine (not shown) in a well known manner. A pair of support spokes 38 extends between the hub member 32 and the curvilinear portion 14 to provide proper rigidity to the structure. A control lever, generally shown at 42, is positioned for engagement with the second junction 28 of the steering wheel. The control lever defines a grasping portion 44 that has a length that is capable of fitting within the palm of the hand of a machine operator. In the disclosed embodiment, the grasping portion 44 is positioned at a substantially horizontal orientation. A post member 46 has a first end portion 48 connected with the grasping portion and a second end portion 50 that defines a circular base that is sufficient for receipt within the bore 30 defined by the second junction 28. The post member 46 is mounted within the bore 30 for rotation with respect to the steering wheel 12 about a second axis 51. The second axis is shown to be substantially parallel to the first axis 37 and substantially perpendicular to the grasping portion 44. In the illustrated embodiment, the post member 46 extends upwardly from the steering wheel 22 an amount that is sufficient to accommodate the operator's hand. In order to provide the required clearance and yet not position the operators hand too far away from the steering wheel, the steering wheel in the area of the second junction 28 is shown to be elevationally lower than the rest of the steering wheel .

A control mechanism 52 is included in the control lever 42 and includes a pair of switch assemblies 54 and 56. A first switch assembly 54 is shown to be a three position switch that controls the gear range of a transmission assembly (not shown) that powers the machine. The first switch assembly is positioned on the end portion of the control lever closest to the hub member 32, which is the right end as viewed in Fig. 2. The first switch is positioned on a first side 58 of the grasping portion 44, which in the illustrated embodiment faces the operator. This positioning places the first switch assembly 54 in close proximity to the thumb of an operator as his left hand engages the grasping portion 44. A second switch assembly 56 is positioned on a second side 60 of the grasping portion 44, which is opposite from that of the first switch assembly 54. The second switch assembly is also a three position switch and is adapted to control the direction of output of the transmission to control the direction of travel of the machine. The second switch assembly 56 is positioned such that it will be easily engageable with one or two fingers of the operators hand as the grasping portion is engaged. While the illustrated embodiment is disclosed to utilize a control lever that is substantially horizontally oriented and pivots on an axis that is substantially parallel to the first axis 37, it is to be understood that this particular arrangement is merely representative of a number of various control lever configurations and angular relationships that could be employed without departing from the principles of the present invention. For example, the control lever could be of one-piece construction having a base portion mounted to the steering wheel and a grasping portion that extends upwardly therefrom at a preselected angle that would be a comfortable orientation for the hand of an operator. Also, the control switches could be repositioned to a location that is different from those disclosed and yet conveniently located for engagement by an operator. Finally, the mounting of the control lever, while shown at the junction between the curvilinear portion and the planar portion of the steering wheel, may be relocated and still be in a convenient location for the operator. For example, either of the portions of the steering wheel, the planar or the curvilinear, could form an extension that would define a mount for the control lever that would be removed from a juncture between the two portions. It is to be understood that these variations in positions and configurations of the control handle fall within the scope of the invention.

Industrial Applicability

During operation of a machine embodying a steering wheel assembly 10 as set forth above, the steering control system of the machine is operated in a conventional manner with rotation of the steering wheel 12. The steering wheel may be engaged by an operator having one hand on the steering wheel, in the present instance the right hand, that can control all or a portion of the rotation of the steering wheel . The second, or left hand, is placed on the control lever 42 with the palm thereof in engagement with the grasping portion 44. The left hand can also be utilized to assist the right hand in providing rotation of the steering wheel. As the machine is driven, the fingers of the operator's left hand are in position to select the direction of travel, through the forward-neutral -reverse positions of the second switch 56. Once that selection has been made, the proper gear ratio of the transmission may be selected by engagement of the first switch 54 with the operator's thumb. Depression of the upper portion of the switch 54 shifts the transmission to a higher gear ratio while depressing the lower portion of the switch 54 will drop the transmission into a lower gear range. As the steering wheel 12 is rotated about the first axis 37, the operator's left hand will cause the control lever 42 to rotate about the second axis 51, maintaining the orientation of his wrist throughout the movement of the steering wheel in either direction. In doing so, the comfort of the operator as well as the optimum position for efficient transmission control is also maintained. This not only increases the efficiency of machine operation, it reduces the fatigue normally experienced by the operator.

Other aspects, objects and advantages of this invention can be obtained from a study of the drawings, the disclosure and the appended claims.

Claims

1. A steering wheel assembly (10) for a machine, comprising: a support column (36) mounted to the machine ; a steering wheel (12) rotatably mounted to the support column (36) for movement about a first axis (37) and being operably connected to a steering system of the machine to selectively control the direction of movement of the machine upon rotation thereof ; a control lever (42) rotatably mounted to the steering wheel (12) about a second axis (51) for relative movement thereabout with respect to the steering wheel (12) ; a control mechanism (52) mounted on the control lever (42) and being operably connected to at least one machine function for independent control thereof.

2. The steering wheel assembly (10) as set forth in claim 1 wherein the steering wheel (12) defines a first portion (14) that is substantially curvilinear and a second portion (16) that is substantially planar.

3. The steering wheel assembly (10) as set forth in claim 2 wherein the control lever (42) is rotatably mounted generally at a junction (28) between the curvilinear and planar portions (14,16) of the steering wheel (12) .

4. The steering wheel assembly (10) as set forth in claim 1 wherein the control mechanism (52) includes a first switch assembly (54) mounted on a first side (58) of the control lever (42) and a second switch assembly (56) is mounted on a second side (60) of the control lever (42) .

5. The steering wheel assembly (10) as set forth in claim 4 wherein the control mechanism (52) is operably connected to a transmission assembly and the first switch (54) is adaptable to control the gear selection of the transmission assembly and the second switch (56) is adaptable to control the direction of output of the transmission assembly.

6. The steering wheel assembly (10) as set forth in claim 1 wherein the control lever (42) defines a substantially elongated grasping portion

(44) that is engageable by the hand of a machine operator with the hand in a preselected orientation, in a manner wherein the first switch (54) is engageable by the thumb of the operator's hand and the second switch (56) is engageable by at least one finger, said control lever (42) being positioned in a substantially perpendicular orientation with respect to the second axis (51) .

7. The steering wheel assembly (10) as set forth in claim 6 wherein the grasping portion (44) may be engaged by the hand of an operator to rotate the steering wheel (12) in either of a first and second direction about said first axis (37) and wherein relative rotation of the control lever (42) with respect to the steering wheel (12) during rotation of the steering wheel permits the operator to substantially maintain the preselected orientation of the hand during rotation of the steering wheel (12) .

8. The steering wheel assembly (10) as set forth in claim 1 wherein the control lever (42) is mounted to the steering wheel (12) by a post member (46) to position the control lever (42) at an elevation slightly above that of the steering wheel (12) .

9. The steering wheel assembly (10) as set forth in claim 6 wherein the grasping portion (44) of the control lever (42) is positioned at a substantially horizontal orientation.

10. The steering wheel assembly (10) as set forth in claim 2 wherein the curvilinear portion (14) of the steering wheel (12) is substantially semi- circular and terminates at a respective first and second end portions (18,20) and the planar portion (16) has a first end portion (22) connected to the first end portion (18) of the curvilinear portion (14) and a second end portion (26) that terminates at a location that is spaced from the second end portion (20) of the curvilinear portion (14) .

11. The steering wheel assembly (10) as set forth in claim 10 wherein a hub member (32) is defined by the steering wheel (12) and is positioned substantially equidistantly between the end portions (22,26) of the planar portion (16) of the steering wheel (12) and is substantially centered about the first axis (37) .

12. The steering wheel assembly (10) as set forth in claim 11 wherein the grasping portion (44) of the control lever (42) is positioned at an angle with respect to the first axis (37) and extends upwardly from the second end portion (26) of the planar portion (16) of the steering wheel (12) and inwardly toward the hub member (32) of the steering wheel (12) .