Spring devices – Centering device
Reexamination Certificate
1999-05-13
2001-05-29
Oberleitner, Robert J. (Department: 3613)
Spring devices
Centering device
C267S034000, C267S221000
Reexamination Certificate
active
06237904
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to motion stabilizers, and more particularly to devices including a spring and a telescoping body assembly for yieldingly holding a load in a normal or centered position.
There is a long standing need for a stabilizer for stabilizing the movement of a load that is movable relative to another load or a relatively fixed support. Such a stabilizer should yieldingly hold the load in a normal position. In may instances the normal position is a centered position in a range of movement of the load. The stabilizer should include a reaction unit having a spring acting through a body assembly to permit the load to be displaced from the normal position and to resiliently bias the load to return from the displaced position back toward the normal position.
There are numerous and varied applications for a motion stabilizer of this kind. One example of an application exhibiting such a need is the steering system of a large vehicle such as a truck or recreational vehicle. In this application, the motion stabilizer urges the steering gear toward a normal or centered position in which the vehicle travels straight ahead, and permits the steering gear to be displaced so that the vehicle can be turned. In a vehicle application, a motion stabilizer should be able to hold the vehicle under control in the presence of cross winds, road irregularities, tire blow outs and the like. Other applications for motion stabilizers include conveyors and manufacturing equipment, power boats, vehicles of many types and trailer hitch systems. A motion stabilizer can provide advantages in many situations where a movable load must be yielding held in a centered or normal position.
Many stabilizing or centering systems have been developed or proposed in the past. For example, U.S. Pat. Nos. 1,223,573 and 4,406,473 disclose vehicle steering stabilizer systems using a pair of coil springs urging a component of the vehicle steering linkage toward a centered or normal position. In another example, U.S. Pat. No. 4,822,012 discloses a bidirectional steering stabilizer having a single spring and a damper for yieldably biasing the wheels of a vehicle toward a straight ahead direction. Although these systems are relatively simple in that they are mechanical devices with relatively few parts, they suffer from disadvantages including interfering with the operator's ability to control the vehicle in a natural way, and a lack of the ability to accommodate a variety of types of springs and reaction units and the ability to easily adjust the stabilizer to match the requirements of a particular vehicle or application.
Another approach that has been used in the past is to provide a complex hydraulic and pneumatic system for assisting the power steering system of a large vehicle in holding the steering linkage and wheels on center. One example of a system of this type is the Howard Power Center Steering System sold by River City Products, Inc. of San Antonio, Tex. Although this steering control system performs well, it is subject to the disadvantages of complexity and large expense, and it is not easily adaptable to a variety of differing applications.
SUMMARY OF THE INVENTION
A principal object of the present invention is to provide an improved motion stabilizer for controlling relative movement of two relatively movable loads. Other objects are to provide a motion stabilizer including a spring and a telescoping body assembly for yieldingly urging a load member toward a normal or centered position; to provide a motion stabilizer that can extend the utility of a reaction unit such as a gas spring by doubling its stroke and providing a two-way action; to provide a motion stabilizer that can accommodate many types of reaction units such as compression or extension springs of several types, dampers and combinations of springs and dampers; to provide a motion stabilizer that can be tailored to optimize the operating characteristics required for many different applications such as vehicle steering systems and industrial applications; to provide a motion stabilizer that is bidirectional and symmetrical in operation; and to provide a motion stabilizer overcoming disadvantages of motion stabilizing and centering systems used in the past.
In brief, in accordance with the invention there is provided a motion stabilizer for controlling motion between first and second relatively movable load members. The motion stabilizer includes an elongated body assembly defining an axially extending internal chamber. The body assembly includes axially spaced first and second attachment members for connection to the load members. A reaction unit is captured within the chamber and has an axial length that varies between first and second lengths. The body assembly has an axial length variable in response to relative motion of the attachment members. The body assembly has a normal position in which the reaction unit has the first length and in which the attachment structures are separated by a predetermined distance. The body assembly includes means for varying the axial length of the reaction unit from the first length toward the second length in response to relative axial movement of the attachment structures in either axial direction from the normal position. The body assembly includes at least a radially inner body member and a radially outer telescoped body member, the body members being axially movable relative to one another. The radially inner body member defines at least part of the chamber and has a force transfer portion engageable with the reaction unit. The inner body member includes an elongated axial opening proving access from the chamber to the radially outer body member. The reaction unit includes a force transfer portion extending radially from the chamber through the axial opening for engagement with the radially outer body member.
REFERENCES:
patent: 1223573 (1917-04-01), Eldredge
patent: 4406473 (1983-09-01), Sexton
patent: 4736931 (1988-04-01), Christopherson
patent: 4822012 (1989-04-01), Sketo
patent: 5454550 (1995-10-01), Christopherson
Industrial Gas Springs Inc. Brochure Apr. 1997.
Safe-T-Plus Brochure Nov. 1997.
Kolehmainen Philip M.
Mason, Kolehmainen Rathburn & Wyss
Oberleitner Robert J.
Rodriguez Pamela J.
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