Land vehicles – Wheeled – Occupant propelled type
Reexamination Certificate
1998-07-24
2001-05-01
Boehler, Anne Marie (Department: 3618)
Land vehicles
Wheeled
Occupant propelled type
C280S240000, C280S244000
Reexamination Certificate
active
06224078
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to occupant-propelled vehicles. More particularly, the present invention is directed to vehicle steering arrangements for occupant propelled vehicles.
BACKGROUND OF THE INVENTION
One knowledgeable in the art of occupant-propelled vehicles will be readily aware that there is a deficiency in the prior art relative to the steering of occupant-propelled vehicles such as wheel chairs. The problem is particularly prevalent with chairs propelled by a single-arm force receiver, such as a drive lever. Steering with such prior art devices has proven mechanically and functionally complex, commonly presenting users with an ergonomically unfriendly steering apparatus.
For example, in some devices, a user is required to rotate a control grip about an axis that is generally perpendicular to the user's arm to rotate a caster wheel via a chain, joint, or lever connection. In some steering mechanisms of this type, the grip communicates along its axis of rotation. In others, the grip is perpendicular to its axis of rotation. In both arrangements, many find the required contortion of one's wrist and arm while expending a driving force upon a force-receiving lever difficult and uncomfortable. Furthermore, the steering direction inadvertently may be affected by one's exertion of a propelling force.
Similarly inefficient and uncomfortable are prior art steering devices that require a user to rotate a shovel type handle. Other steering systems include complex multi-gear force transmission arrangements, and prior art systems commonly do not provide a means for disengaging the steering controls to allow free motion of the caster as would be useful when the chair is to be pushed by a second person.
In total, one sees that prior art occupant-propelled vehicle steering arrangements are undesirably complex and uncomfortable to operate. Consequently, it would be advantageous if one were to provide a steering arrangement that is simple, effective, and durable while being comfortable to operate.
SUMMARY OF THE INVENTION
Advantageously, a principal object of the present invention is to provide a steering arrangement for occupant-propelled vehicles that presents a solution to the deficiencies left by prior art steering arrangements for occupant-propelled vehicles.
Stated more particularly, the invention has primary objects of providing a vehicle steering arrangement that is simple in both manufacture and use.
It is a further object of the invention to provide a vehicle steering arrangement that accommodates the ergonomic needs of users of occupant propelled vehicles.
Still further objects of the present invention are to craft a vehicle steering arrangement for wheel chairs that enables effective steering control of a steered wheel or wheels by an occupant, including providing any necessary or desired mechanical advantage, while allowing the vehicle steering arrangement to be disengaged from the steered wheel quickly and easily to allow free rotation of the steered wheel.
These and many other objects and advantages of the present invention will become obvious both to one who reads the present disclosure and reviews the accompanying figures and to one who has the opportunity to take advantage of an embodiment of the present invention.
In accomplishing the aforementioned objects, one embodiment of the present invention contemplates an occupant-propelled vehicle comprising a vehicle frame, a vehicle propulsion system operably associated with the vehicle frame with a movable force receiver for receiving an input force from an occupant, and a vehicle steering arrangement. Essentially, one preferred vehicle steering arrangement overcomes the previously-described disadvantages found in the prior art by providing a tilt-grip steering post pivotally attached to the force receiver, a steering drum coupled to the tilt-grip steering post, a steered drum coupled to a steered wheel that is steerable about a steering axis, a flexible, sleeved cable overlying and engaged with the steering drum and the steered drum whereby a pivoting of the tilt-grip steering post causes a rotation of the steering drum that yields a reciprocation of an inner member of the sleeved cable that causes a rotation of the steered drum to induce a steering rotation of the steered wheel about the steering axis.
Preferably, the tilt-grip steering post will have an axis of rotation perpendicular to a longitudinal axis of the tilt-grip steering post. Still more preferably, the tilt-grip steering post will have an axis of rotation tangent to an arc of rotation of the moveable force receiver. This particular aspect of the steering arrangement allows the invention to overcome many of the disadvantages found in the prior art, particularly the ergonomic disadvantages summarized above. By providing a tilt-grip steering post with an axis of rotation tangent to the arc of rotation of the moveable force receiver, an occupant is able to operate the steering system comfortably and effectively even while exerting significant force to move the moveable force receiver to propel the vehicle.
In any event, the vehicle frame may be a wheel chair frame with more than two wheels wherein the steered wheel is a caster with a yoke rotatable about a yoke stem, which acts as the steered wheel's steering axis. With a vehicle having four or more wheels, it may be preferably to have one of the wheels vertically biased toward a surface on which the vehicle travels to ensure contact of the steered wheel with the ground even on uneven terrain. In particular applications, a manipulation of the relative sizes of the drums may be desired. For example, one might desire that a given tilt of the tilt-grip steering post would result in an amplified rotation of the steered wheel. This could be accomplished by causing the steering drum to be relatively larger than the steered drum by a selected ratio.
Since there may be times when free rotation of the steered wheel may be desired, the steered drum may be disengagably indexed with the steered wheel by an means for indexing the steered drum to the steered wheel such as by a set screw, a pin that is slidably engagable with the steered drum and the yoke of the steered wheel, or a gross tension adjustment where friction is used to index the cable to the steered drum. For most effective steering, it may be desirable to couple the steered wheel to a second wheel of the vehicle for steering the second wheel in response to a steering of the steered wheel. This may be done by a number of means such as by a flexible shaft, a tie rod, or a toothed belt.
Providing a means for maintaining and/or adjusting the neutral position of the steering assembly also may improve the assembly's overall function. For example, an end of the outer sheath may be threadedly connected to the vehicle frame such as at the force receiver for adjustment relative thereto to change the effective length of the cable sheath. Alternatively, the effective length of the cable sheath may be adjusted by a threaded connection of a first section of a body portion of the sheath with a second section of the body portion of the sheath.
An alternative vehicle steering arrangement similarly comprises a steered wheel and a tilt-grip steering post, and a flexible, sheathed cable. However, in this alternative embodiment, the sheathed cable has an inner member that is capable of transmitting loads in tension and compression within an outer sheath. As such, this steering arrangement may be considered a push/pull arrangement since the sheathed cable pushes the steered drum to steer in one direction and pulls the steered drum to steer in a second direction. In any event, a first end of the cable is coupled at a pivot point to the steering post, and a second end of the cable is coupled at a pivot point to the steered wheel such that a pivoting of the steering posts yields a reciprocation of the inner member and a consequent steering of the steered wheel about its steering axis.
In a manner similar to the first steerin
Boehler Anne Marie
Lerner Avraham H.
O'Connell Law Firm
LandOfFree
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