Land vehicles – Wheeled – Running gear
Reexamination Certificate
2000-07-12
2002-03-05
Mai, Lanna (Department: 3619)
Land vehicles
Wheeled
Running gear
C280S124106, C280S124116, C280S124128, C267S124000, C267S064120, C267S064150, C188S282700, C188S287000
Reexamination Certificate
active
06352271
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
REFERENCE TO A “MICROFICHE APPENDIX”
Not Applicable
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a combination hydraulic and pneumatic cylinder which has a valve in the piston to control the rate of movement of the piston. In particular, the present invention relates to a combination hydraulic and pneumatic cylinder for use in controlling the handling of a vehicle around curves. The cylinder controls the movement of at least one of the rear wheels of the vehicle during cornering.
(2) Description of the Related Art
The related art has shown various pneumatic, hydraulic and olepneumatic cylinders using a variety of different constructions to control the movement of the piston of the cylinder. In particular, the related art shows cylinders where a bore is provided through the piston rod to allow fluid to move between chambers of the cylinder through the piston rod. Illustrative are U.S. Pat. Nos. 3,110,485 to Axthammer and 4,405,119 to Masclet et al.
Axthammer shows a hydro-pneumatic suspension device. The device includes a hollow shell with a cavity having a transverse partition dividing the cavity into a storage space and a pressure space. The free end portion of the plunger is located in the pressure space. The plunger has an axial cavity which extends over a major portion of the plunger length. The cavity is in fluid communication with the storage space. An elongated open groove is formed in the outer surface of the plunger near its inner end portion. The groove forms a passage from the pressure space to the storage space. The storage space and pressure space are divided into three chambers. A tubular piston having an axial bar projects from the bottom of the shell into the pressure chamber. Entry of the piston into the bore during downward movement of the plunger substantially closes the cylinder space of the pump constituted by the piston and the lower end of the plunger.
Masclet et al shows an olepneumatic suspension having a rod sealingly mounted for sliding movement inside a cylinder filled with hydraulic liquid. A guide rod fixed with respect to the bottom of the cylinder passes through a central passage provided in the piston. The piston also has two (2) valves with permanent throttle orifices of different cross-sections. The orifice of greater cross-section provides throttling in the compression phase and the orifice of smaller cross-section provides throttling in the extrusion phase.
Also of interest are U.S. Pat. Nos. 2,141,541 to Levv; 2,397,640 to Bingham; 2,823,915 to Bourcier De Carbon; 3,706,362 to Faure and 4,131,139 to Tanabe which show various types of valved orifices located in pistons of a cylinder to provide dampening to the cylinder.
There remains the need for a combination hydraulic and pneumatic cylinder for use in controlling the cornering ability of a vehicle which controls the rate of movement of the piston in the cylinder in two (2) ways. The cylinder uses a passageway through the piston rod to control the rate of extrusion and compression of the cylinder and a control valve in the piston to allow fluid flow between the chambers of the cylinder.
SUMMARY OF THE INVENTION
The present invention is a hydraulic and pneumatic cylinder for use on a vehicle to improve the handling of the vehicle in a turn or curve. The cylinder repositions the rear wheel of the vehicle in response to a change in the speed of the vehicle. The cylinder can be used on racing vehicles to allow for better handling of the vehicle in turns at high rates of speed. The cylinder has a body and a piston member. The body of the cylinder has opposed end caps with a cylinder bore extending therebetween. The piston member includes a piston and a piston rod. A divider wall extends across the cylindrical bore to divide the cylindrical bore into two chambers. The divider wall has a center opening to allow the piston rod to extend through and a side opening to allow fluid in the body to pass between the chambers. The first end cap has a guide pin which extends into a center bore in the piston. The center bore in the piston is in fluid communication with a center bore and side bore in the piston rod. The guide pin is smaller in diameter than the center bores of the piston and piston rod such that fluid is able to pass around the guide pin to move from one side of the piston to the other side of the piston. The piston is provided with a control valve having an adjustment cylinder and a valve mounted in a valve bore. An end of the valve pin extends beyond the valve bore and contacts the divider wall as the piston is moved toward the divider wall. Contact of the valve pin with the divider wall moves the valve to the fully open position. The control valve helps to provide a controlled rate of extension and compression of the cylinder. The cylinder is preferably mounted between a frame of the vehicle and a lower control arm for the rear, passenger wheel of the vehicle.
The cylinder extends and compresses in response to a change in the rate of speed of the vehicle. When the vehicle enters a turn and decelerates, the piston of the cylinder moves to the extended position. As the cylinder moves to the extended position, fluid on one side of the piston pushes against the valve pin of the control valve to open the control valve. When the cylinder is almost in the fully extended position with the piston adjacent the divider wall, the end of the valve pin contacts the divider wall and moves the control valve to the fully open position. When the vehicle exits the turn and accelerates, the piston of the cylinder moves to the compressed position. The cylinder allows the rear wheel on the passenger side of the vehicle to move backwards toward the rear end of the vehicle when the vehicle decelerates. Moving the rear wheel backwards allows for greater steering ability and better handling ability in turns at high speeds.
The present invention relates to a combined pneumatic and hydraulic cylinder, which comprises: a body having opposed open first and second ends with a bore extending therebetween defined by an inner sidewall around a longitudinal axis of the cylinder; a first end cap mounted on the open first end of the body and having a guide pin extending along the longitudinal axis of the cylinder and projecting into the bore; a divider wall mounted in the bore between the ends of the body and having a center opening around the longitudinal axis and a side opening extending parallel to and spaced apart from the longitudinal axis wherein the side opening allows for fluid flow through the divider wall; a second end cap mounted on the open second end of the body and having a center opening around the longitudinal axis; a piston member including a rod with a piston at one end wherein the piston member is mounted such that the rod sealingly extends through the center opening in the second end cap along the longitudinal axis with the piston slidably mounted in the bore between the first end cap and the divider wall with the piston in a sealed relationship with the inner wall of the body, the rod including: (i) a center bore along the longitudinal axis; and (ii) a side bore adjacent to the piston and in fluid communication with the center bore of the rod; the piston including: (i) a center bore along the longitudinal axis wherein the center bore of the piston is in fluid communication with the center bore and the side bore of the rod and wherein the guide pin of the first end cap extends into the center bore of the piston towards the rod; and (ii) a valve means which is opened when the piston is moving toward the divider wall; and a means mounted on the body for introducing a pneumatic fluid into the bore in the body between the second end cap and the divider wall, wherein the cylinder is mounted in a substantially horizontal orientation between objects which are in motion relative to each other and provides a controlled movement of at least
Mai Lanna
McLeod Ian C.
Moyne Mary M.
To Toan C
LandOfFree
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