Shock absorber apparatus

A shock absorber includes a first cylinder having a first fluid port and a second cylinder having a second fluid port. A response adjustment mechanism is connected in fluid transmission relation between the first and second fluid ports.The response adjustment mechanism includes three adjustable valves for controlling the operation of the shock absorber. One of the adjustable valves has a stem that is rotatable by a tool during operation. The remaining adjustable valves each have a shaft that is rotatable by a tool during operation.The adjustable valves of the response adjustment mechanism are coaxially positioned so that a first valve is coaxially positioned within a second valve, and the first and second valves are coaxially positioned within a third valve.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a shock absorber, and more particularly to a shock absorber incorporating improved dampening response mechanisms and more specifically to a shock absorber having a versatile adjustable response mechanism for tuning the performance of the shock absorber apparatus.

2. Description of Related Art

Shock absorber systems have been in use for damping the reaction forces experienced with wheeled vehicles throughout the use of the wheel as a means of transport. Shock absorbers are well known in the art and have been used successfully for many years to improve the safety and handling of many types of vehicles. The design of the shock absorber has often been challenging due to the nature of the dynamic motion of a vehicle as it travels over widely varying terrain and driving conditions. Shock absorber performance, though improved over the last few decades, is still far from optimum. Often, the constraints and criteria used in the design of a shock absorber are counter to one another, and force the designer to balance tradeoffs. The result is a shock absorber having performance that often delivers compromising results.

In certain applications, shock absorber systems are taken to extremes, providing even further challenges for the designer. For example, in the field of off-road motorcycle racing, a shock absorber is exposed to widely varying conditions as the vehicle is raced along a course of travel. Furthermore, the performance of the shock absorber system can make a dramatic impact on the safety and performance of the motorcycle.

For optimum performance, the response of a shock absorber often must be tuned or adjusted for the conditions in which it will be used. However, many shock absorber systems available on the market today have a limited tuning capability. Further, those with an adjusting or tuning capability, are often difficult to adjust, resulting in mal-adjustments of the shock absorber which degrades the performance even further.

The motorcycle shock absorber is relied upon by riders to provide comfort and stability as well as to enhance the performance of the motorcycle. One of the preferences of riders over rough and varied terrain, is to have the responsive handling while preventing the bone jarring jolts to the rider created when the motorcycle impacts into bumps on the terrain. In the motorcycle application, the shock absorber must provide a steady and consistent ride over flat terrain. The flat terrain will not create instantaneous jarring reaction forces. The shock absorber will react to the flat terrain with low speed control. The piston in the cylinder of the shock absorber will translate in the cylinder at a low speed. The shock absorber is required to provide a steady and consistent ride over moderate terrain. The moderate terrain will create moderate reaction forces that cause the shock absorber to translate at a mid or medium speed. It is desirable for a shock absorber to have mid or medium speed control for the moderate terrain where the shock absorber is required to absorb occasional jolts while maintaining a stiff response over the moderate terrain. In addition, the shock absorber is required to provide a stable and consistent ride over rough and choppy terrain. The rough and choppy terrain will cause instantaneous jarring reaction forces on the shock absorber. The shock absorber will react to the rough and choppy terrain with high speed translation. The shock absorber needs high speed control for the high speed translation. The shock absorber is required to dampen the sudden impact forces without a hard stiff jolt. Unfortunately, up to this point, it has been difficult to realize a shock absorber, having a suitable response for the varying types of terrain cited above.

There have been many attempts to some of these problems with varying degrees of success. For example, U.S. Pat. No. 5,810,128 teaches an improved shock absorber having an improved transition between a first and second damping rates. Yet further, U.S. Pat. No. 6,446,771 provides an improved bleed function and non-return valve arrangement. And further, U.S. Pat. No. 6,116,338 teaches an improved compression stroke valve in an attempt to improve the performance of a shock absorber system.

Several attempts have been made to overcome the deficiencies found in the state-of-the-art shock absorbers by designing support systems which reduce the effects of the inherent deficiencies in state-of-the-art shock absorbers. For example, linkage systems have been incorporated on vehicles to modify the motion experienced by the shock absorber to better match it the vehicle system. Unfortunately, while such attempts improve the performance, they also add cost and weight to the vehicle.

Therefore, it is evident that a versatile and adjustable shock absorber is needed to overcome these and other deficiencies in the prior art. The subject invention for a shock absorber apparatus overcomes the perceived shortcomings and detriments in the prior art apparatuses and is the subject matter of the present application.

SUMMARY OF THE INVENTION

A first aspect of the present invention relates to a shock absorber apparatus, having a first cylinder defining a first internal bore closed by a first end wall and an opposite second end wall, and further has a first port connected in fluid transmission relation to the first internal bore, and a second cylinder defining a second internal bore closed by a first end wall and an opposite second end wall, and a second port connected in fluid transmission relation to the second internal bore, and a response adjustment mechanism located adjacent to the second cylinder, and connected in fluid transmission relation between the first port and second port, and has three or more adjustment operators which are operable to direct the fluid flow between the first port and the second port.

Another aspect of the present invention relates to a shock absorber apparatus, having a first cylinder defining a first internal bore and having an internal diameter, and closed by a first end wall, and further closed by an opposite second end wall, and further having a first port connected in fluid transmission relation to the first internal bore, and a rod having a first end and an opposite second end, and wherein the rod movably extends into the first internal bore through an aperture formed in the first end wall so that the second end of the rod is positioned concentrically within the first internal bore, and so that the first end of the rod is positioned outside the first internal bore, and a first piston fixedly attached to the rod at an intermediate position located between the first and the second end of the rod, and positioned concentrically within the first cylinder, and a second piston fixedly attached to the rod proximate to the second end of the rod, and positioned concentrically within the first cylinder; a second cylinder defining a second internal bore closed by a first end wall and an opposite second end wall, and having a second port connected in fluid transmission relation to the second internal bore, and having and a response adjustment mechanism located adjacent to the second cylinder, and connected in fluid transmission relation between the first cylinder port and the second cylinder port, and wherein the response adjustment mechanism is configured to provide three or more adjustments for tuning the response of the shock absorber system.

Still further, another aspect of the present invention relates to a shock absorber apparatus, having a housing comprising a first internal bore having a diameter, and further comprising a second internal bore having a diameter, and wherein the housing is closed by a first end wall, and further closed by an opposite second end wall, and a rod having a first end and an opposite second end, and wherein the rod movably extends into the first and/or second internal bore through an aperture formed in the first end wall so that the second end of the rod is positioned concentrically within the first internal bore or second internal bore, and so that the first end of the rod is positioned outside the housing, and a first piston having a diameter, and fixedly attached to the rod at an intermediate position located between the first and the second end of the rod, and positioned within the first internal bore in sliding relation, and a second piston, having a diameter, and fixedly attached to the rod proximate to the second end of the rod, and positioned within the first and/or the second internal bore in sliding relation, and wherein the diameter of the first piston is approximately equal to the diameter of the first internal bore, and wherein the diameter of the second piston is approximately equal to the diameter of the second internal bore, and further wherein the diameter of the second piston is less than the diameter of the first piston.

And still further, another aspect of the invention relates to a shock absorber apparatus, having a first cylinder bore having a diameter and having a longitudinal axis, and filled with an incompressible fluid, and having a second cylinder bore having a diameter, and filled with the incompressible fluid, and positioned adjacent to the first cylinder bore, and along the longitudinal axis of the first cylinder bore, and having a piston rod having a first end, and an opposite second end, and a longitudinal axis, and an external surface, and wherein the first end is positioned outside the first and second cylinder bore, and wherein the second end is positioned within the first or the second cylinder bore, and the longitudinal axis of the piston rod is positioned concentric to, and along, the longitudinal axis of the first cylinder bore, the piston rod further comprising a bore formed concentrically therein, and wherein the piston rod further comprises a one or more of apertures formed within the piston rod and extending from the external surface of the piston rod into the bore of the piston rod to form a fluid passage, and having a first piston positioned at an intermediate position located between the first and the second end of the piston rod, and configured to translate within the first cylinder bore in response to an external force, and having a second piston positioned proximate to the second end of the piston rod, and configured to translate within the first cylinder bore, and in the second cylinder bore, and in response to the external force, and a needle assembly located substantially within the second cylinder bore, and configured to enter the bore of the piston rod as the second piston nears the second cylinder bore, and wherein the diameter of the second cylinder bore is less than the diameter of the first cylinder bore.

Yet further, another aspect of the invention relates to a shock absorber apparatus, having a housing, and a cylinder bore enclosed by the housing, and further having a longitudinal axis, and a rod substantially positioned concentric to, and along, the longitudinal axis of the cylinder bore, and partially positioned within the cylinder bore; a piston fastened to the rod, and slidingly positioned within the cylinder bore, and a pressure plate slidingly positioned on the rod, and positioned adjacent to the piston, and a plate spring retainingly mounted to the pressure plate.

And another aspect of the invention relates to a shock absorber apparatus having a housing, and a cylinder bore enclosed by the housing, and having a longitudinal axis, and a rod having a first end and an opposite second end, and wherein the rod is substantially positioned concentric to, and along, the longitudinal axis of the cylinder bore, and wherein the first end of the rod is positioned within the cylinder bore, and a piston fastened concentrically to the rod, and movably positioned within the cylinder bore, and a step washer positioned concentrically around the rod in stacking relation, and positioned proximate to the piston, and a pressure plate positioned concentrically around the step washer in sliding relation, and a plate spring positioned concentrically around the rod so that it is borne by the step washer, and further wherein a portion of the plate spring is held in tension by the pressure plate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIG. 1, an exemplary shock absorber constructed in accordance with an embodiment of the invention is identified generally by the reference numeral10. The shock absorber10is designed to be positioned between a vehicle chassis (not shown), and a wheel-carrying hub (not shown) in a manner known in the art. The suspension unit10includes a cylinder assembly or housing12which is provided with a first end wall or cap14. The end wall14carries a bracket16so as to provide a pivotal connection to the vehicle chassis (not shown).

The cylinder housing12having a longitudinal axis272includes a cylinder bore24that is closed at one end by the end wall14and at the other end by the gland20. The opposite end of the cylinder housing12is enclosed by an end wall or cap18that carries a sealing gland20. A piston rod22extends through the sealing gland20out of an aperture23formed in the wall18in a sealing arrangement while providing a translational guide for the rod22to allow the rod22to translate within the cylinder housing12. The rod22has an elongated portion on which is carried a yoke26that provides the connection to the wheel-carrying hub (not shown).

A coil compression spring28encircles the cylinder housing12and the exposed end external to the housing12of the piston rod22. One end of this spring28rests against a collar32that is connected to the cylinder housing12. The opposite end of the spring28rests against a spring retainer30that is carried by the piston rod22and is adjacent to the yoke26. In this arrangement, the spring28will be loaded as the piston rod22moves relative to the cylinder housing12upon suspension movement of the wheel or hub relative to the chassis of the vehicle. A snubber34is carried by the spring retainer30and will engage with the end cap18so as to provide a cushioned, yet positive stop, providing a limit to the total compression of the shock absorber10.

Referring still toFIG. 1, the shock absorber10is comprised of a first damping piston36and a second damping piston38having a reduced diameter. Each piston36and38are supported on the piston rod22within the cylinder bore24. The second damping piston38approximately defines a first fluid chamber44between the piston38and the end wall14. A second fluid chamber42is approximately defined between the two pistons36and38and a third fluid chamber40is approximately defined between the first fluid piston36and the gland20. The fluid chambers40,42, and44are filled with a damping fluid such as hydraulic fluid.

The piston rod22has a reduced diameter portion generally indicated by the numeral46which extends from a first end of the rod22to a shoulder48. This reduced diameter portion46is configured to mount and translate in stacking arrangement the components that assist in providing a variable response to external forces. A washer50is positioned in resting relation to the shoulder70. A damping valve assembly52A is positioned over the reduced diameter portion46of the rod22adjacent to the washer50. The first piston36is positioned adjacent to the damping valve assembly52A. Another damping valve assembly52B is positioned adjacent to the first piston36. A spacing sleeve56is positioned adjacent to the damping valve assembly54B and is configured to maintain a spatial distance between the two pistons36and38. The spacing sleeve56has an axial length which can be selected so as to control the spacing between the pistons36and38. Another damping valve assembly52C is positioned adjacent to the spacing sleeve56. The second piston38is positioned adjacent to the damping valve assembly52C. Another damping valve assembly is positioned adjacent to the second piston52D. A holding nut62is positioned in a threaded arrangement onto the reduced diameter portion46of the rod22and, when tightened appropriately, provides a holding force to maintain a spatial relationship between the first and second pistons36and38. The damping valves52A,52B,52C, and52D may be similarly constructed, one to another, but may vary in scale or in characteristics. Alternatively, the damping valves52A,52B,52C, and52D may be constructed using differing elements from each other, and constituting different styles of damping valves.

The piston36is formed with damping flow passages (not shown) which extend therethrough and will be discussed later. The damping valve assembly52A is interposed between the spacer plate50and the piston36and partially controls the flow from the chamber42to the chamber40. The damping valve assembly52B is interposed between the opposite side of piston36and the spacer sleeve56received on the reduced diameter portion46of the piston rod22. The valve assembly52B acts to partially control the flow from the chamber40to the chamber42.

Like the piston36, the piston38has a series of flow passages (not shown) that extend therethrough. Some of the flow in a first direction from the chamber44to the chamber42occurs through certain of these passages at a rate controlled by the damping valve assembly52D depending on the position of the second piston38. Flow from the chamber42to the chamber44is partially controlled by the damping valve assembly52C which is disposed on the opposite side of the piston36.

A further control damping arrangement may be incorporated so as to provide further control of the damping rate. The end64of the piston rod22that extends into the chamber44is provided with a central bore66. This central bore66extends generally to the area where the shoulder48is formed. An orifice plate68is provided that is at least partially closed by an adjustable metering pin70. The position of the metering pin70is controlled by an adjusting rod72that extends through a further bore formed in the rod22. The opposite end of the adjustment rod72has a rounded pin73attached thereto, and is positioned in force transmission relation to a rebound adjustment screw75. This adjustment screw75permits external adjustment of the damping flow through the orifice plate68controlled by the metering pin70.

Still referring toFIG. 1, an arm76extends from the cylinder housing12to an accumulator housing78. The housing78has a first end wall81and a second end wall83. A fluid passage90extends within and through the arm76to a first port94in fluid communication with the chamber44. A response adjustment mechanism88is positioned in fluid communication with the fluid passage90. The response adjustment mechanism88is positioned in fluid communication with a second port92which is positioned adjacent to the accumulator housing78as will be discussed below. The response adjustment mechanism88is configured to provide a user specified variable adjustment to affect the damping characteristics of the shock absorber10. The response adjustment mechanism88includes biasing members for controlling the response of the shock absorber apparatus10by providing a user adjustment for a plurality of speed ranges. The mechanism88can include at least one of a low speed adjustment portion, a medium speed adjustment portion, and a high speed adjustment portion. The low speed adjustment portion of the mechanism88can include a needle flow controller. The medium speed adjustment portion can include biasing members configured to control damping fluid flow as a function of the user adjustment and the pressure difference between the ports94and92. The high speed adjustment portion can include high resistance biasing members configured to control damping fluid flow as a function of the user adjustment and the pressure difference between the ports94and92. The construction and operation of the mechanism88will be discussed in detail at a later point in this specification.

A floating piston80is contained within a bore82of the accumulator chamber78. An inert gas such as nitrogen may fill a chamber84formed on one side of the floating piston80so as to maintain a fluid pressure on the fluid in the shock absorber chambers40,42,44and in a chamber86formed on the head of the floating piston80. The inert gas may be inserted through charging port85through the base of the accumulator78.

The effective inside diameter of the cylinder bore24can be reduced over a portion of its length to provide for an enhanced dampening characteristic as the piston38approaches the wall14. InFIG. 1, a cylindrical insert or sleeve98shown as it is mounted to the internal surface of the bore24of the cylinder housing12proximate to the wall14. The sleeve98may include a taper97to provide a gradual transition to the flow of fluid as the piston38approaches. The shape of the taper97may be selected to tayler the transition to provide a desirable damping characteristic as the piston38approaches and travels through the bore defined by the sleeve98.

Yet further, to enhance the damping characteristics of the shock absorber apparatus10, a needle assembly indicated generally by the reference numeral96is mounted proximate to the end cap14. The needle assembly96is adapted to enter into the piston rod bore66and provide additional control therethrough as will be discussed in greater detail below.

Referring now toFIG. 2, a variation of the shock absorber apparatus10is shown. In this variation, the shape and form of the sleeve98shown inFIG. 1is incorporated into the cylinder or housing367. The housing367defines a first cylinder bore of345concentrically aligned along a longitudinal axis358. A second cylinder bore346is positioned adjacent and concentric to the bore345. The first cylinder bore and the second cylinder bore each have an inside diameter as generally indicated by the numeral348and350, respectively. A piston rod22is concentrically located within the first cylinder bore345and is allowed to translate through an aperture356formed in the first end wall354of the housing367.

In bothFIG. 1, andFIG. 2, a second housing or cylinder78is positioned near the housing12(FIG. 1) and the housing367(FIG. 2). The cylinder or housing78holds an incompressible fluid370and compressible fluid371. The fluid370and the fluid371are separated by the piston80. The response adjustment mechanism88is configured in fluid communication with the incompressible fluid370as it is transferred to and from the bore in the housing78to the housing12(FIG. 1) or the housing367(FIG. 2) via the channel or passageway90. Still further, the cylinder bore24(FIG. 1) or the bore345(FIG. 2) can be configured with one or more grooves356formed into the housing12(FIG. 1) or housing367(FIG. 2). The groove356is positioned proximate to the first piston36and will be discussed in further detail below.

Now referring toFIG. 3, a portion of the shock absorber apparatus10is shown having a piston rod22that is movable in direction generally indicated by the arrow344through an aperture23(FIG. 1) through the first wall18of the housing or cylinder12. The piston rod22is configured to translate within the bore24(FIG. 1) over a range of positions at varying speeds depending on the external forces applied to the rod22and the pinion16. The piston rod22has a second end64and is shown inFIG. 3at a first position338. For reference, when the end64of the rod22is located at the first position, the apparatus10is said to be in its returned state. A second reference point is shown at the point where the end64is located at the position designated by the numeral340. At this point, the apparatus10is said to be in its bottomed state. A distance generally designated by the numeral342is measured as the difference between the first position338and the second position340. The distance342may be considered the stroke length of shock absorber apparatus10. In this specification, when the motion of the rod22is in the direction designated by the arrow344, the motion is said to be compressive; when the motion of the rod22is in the direction designated by the arrow347, the motion is said to be returning.

Furthermore, a low speed definition consists of rod22travel anywhere in the stroke, from zero until the speed and volume of the rod22may overcome a volume movement of liquid through the low speed portion of the response adjustment mechanism88and the dampening valve assembly movement that have been selected and set per leverage and the speed of travel per the shock absorber apparatus10.

Furthermore, a medium speed definition consists of rod22travel anywhere in the stroke, from zero until the speed of the rod22travel has overcome the low speed settings and adjustments. A rod22travel exceeds the resistance of a given low speed volume control to another volume and resistant control. Within the given volume of the rod22and stroke travel per leverage and speed of travel per shock absorber apparatus10.

Finally, a high speed definition consists of rod22travel anywhere in the stroke from zero until the speed has over come the low speed and mid speed adjustments for a given volume per shock and leverage and the speed ratio. A high speed rod travel movement consist of a supposed maximum speed traveled by the rod to control all speeds that can overcome the low and mid speed pathways or rod volume per low and mid speed.

Referring now toFIG. 4andFIG. 5, a cylinder or housing12is shown position positioned along the longitudinal axis272. The piston rod22extends into the cylinder or housing12through an aperture23as shown inFIG. 1. A first piston36is fastened to the rod22and is translatable in a space formed by the housing or cylinder12as generally indicated is the cylindrical bore having the numeral24. A first chamber40is defined by the position of piston36. A second piston38(FIG. 1) is shown, and also positioned on the piston rod22, and defines a second chamber42(FIG. 1). The cylinder or housing12defines an internal bore24that forms an internal surface302. The surface302may include one or more grooves356which are formed into the cylinder or housing12. The groove356forms a communication channel between chambers40and42, providing a bleed or bypass flow360when the first piston36is proximate to the groove356. The groove356provides an enhancement to the flow of the incompressible fluid around the first piston36and can be configured to affect a desirable dampening characteristic. The location of the one or more grooves356may provide a variable damping characteristic that may be configured by choosing the location, width, length, depth, and taper of the groove356relative to the location of piston36and the first position338(FIG. 3). In a preferred embodiment, the groove is positioned proximate to the piston36when the shock absorber apparatus is configured near its bottomed state, and has an initial depth at the first end of the groove356proximate to the end wall18, and further has a depth that is taped along its length so that the depth at a second opposite end356is less than the depth at the first end. The groove356has been shown to provide a desirable dampening characteristic during low-speed operation of the shock absorber apparatus10.

Now referring toFIG. 6a simplified view of the upper portion of the shock absorber apparatus is shown. A sleeve98a shown position proximate to the second end wall14of the housing or cylinder112. The sleeve98has an outside diameter277and an inside diameter276and is positioned along and concentric to the longitudinal axis272. A first piston36is shown having an outside diameter as generally indicated by the numeral274positioned on the piston rod22(FIG. 1). A second piston38is shown having an outside diameter as is generally indicated by the numeral279and is positioned near the second end64of the piston rod22as shown inFIG. 1. A needle assembly96is shown attached to the second wall14of the housing or cylinder12and extends into the second cylindrical bore24. A piston rod22includes a bore66which is drilled concentrically through its length.

The outer diameter274of the piston36is selected so that the piston36may move in a sealing fashion within the cylinder bore24. This outside diameter274is approximately equal to the dimension277is only different by the amount of clearance required for tolerance and to provide a slideable fit. Similarly, the second piston38A has the outside diameter279is configured with an outside diameter similar to the inside diameter of the sleeve98as indicated by a the dimension276. The dimension279and the dimension276are approximately equal and are selected such that the second piston38is able to movably translate within the cylindrical bore24.

The piston38A is shown as a variation of piston38having a cup shaped surface39defining a crown43having a height dimension generally indicated by the numeral41. The piston38A also may have a cylindrical shape without the indentation shown on piston38for the sealing band. For this specification, piston38A and piston38are identical in other respects.

Still referring toFIG. 6, a needle assembly96is positioned adjacent to the second and wall14of the housing or cylinder12. The needle assembly is concentrically positioned along the longitudinal axis272of the bore24. The needle assembly96extends from the second wall14toward opposite end of the cylinder bore24and extends beyond the edge97of the sleeve98. The needle assembly96may be configured with straight sides, or alternatively, may have a taper to accomplish a damping characteristic. Regardless of the shape of the needle assembly96, however, the outside diameter of the assembly96is selected to fit within the bore66of the rod22as the hydraulic apparatus approaches its bottomed state. The piston rod22further includes one or more apertures366formed therein and extending to the bore66to provide a fluid path as will be discussed below.

Referring now toFIG. 7, a needle assembly96is shown. The assembly96includes a needle member285having a bore284and a first end281an opposite second end282. The needle member285may be tapered over its length to affect a dampening characteristic of the shock absorber10. The first end281is attached to the wall14(FIG. 1) or alternatively to353(FIG. 2). The member285has an end wall283positioned proximate to the end282. An aperture286is formed in the wall283forming a fluid passage between the bore284and the bore24when it is unobstructed. Another aperture288is formed on the surface of the member in intermediate position between and the end281and the end282. A helical spring291is shown inserted into the member285and is shown extending from the end281to the end282. The first end292of the spring291is positioned adjacent to a sphere290. From the drawing, it should be apparent that the sphere290and the spring291may move within the tube285within the bore284. This sphere290is shown positioned adjacent to the aperture286and serves to obstruct the aperture286reducing or blocking the fluid passage formed by the combination of the aperture286to the bore284to the aperture288when the force upon the sphere290imparted by the incompressible fluid is insufficient to overcome the load provided by the spring291in concert with the gravitational force and inertial forces exerted on the sphere. A fluid flow (not shown) may enter the aperture286and flow through the bore284an exit the aperture288causing an upward force on the sphere290which causes the spring291to contract allowing fluid flow freely. Alternatively if there is a pressure at the aperture288which initially causes fluid to flow from288to the aperture286this will cause a force on the sphere290to cause it to translate towards the end282until it contacts and it reduces or restricts the fluid flow between the aperture288and the aperture286. In this respect, it should be understood, that the needle assembly96may act as a check valve allowing flow from the aperture286to the aperture288and restricting flow that from the aperture288to the aperture286. The tube285has an outside diameter generally indicated by the dimensional measurement275and is configured to be less than the inside bore66diameter within the piston rod22. Thus, the dimension275should be less than the dimension278(FIG. 6).

Now referring toFIGS. 8A,8B, and8C, a sequence is shown of the shock absorber assembly with an interaction between the piston rod22and the needle assembly96as well as an interaction between the second piston38and the sleeve98. As shown inFIG. 8A, the piston rod22is shown proximate end of the needle assembly96. However, in the position shown, needle assembly96has not yet entered the bore66of the rod22. Now referring toFIG. 8B, the rod22is shown in an advance position relative to the position shown inFIG. 8A. As shown in the drawing, the assembly96has entered the bore66of the rod22. Now referring toFIG. 8C, the needle assembly96is shown partially engaged in the bore66of the rod22. Furthermore, the second piston38is shown in a position that is adjacent to the sleeve98.

Now referring toFIG. 9, the response adjustment mechanism88is shown in a cross sectional view. The response adjustment mechanism88, and in a preferred embodiment, includes three adjustable valves concentrically located and coaxially positioned, one within the other, and along a longitudinal axis100. A first adjustment valve103is shown as the innermost valve, and centered along the longitudinal axis100. A third adjustment valve107is shown as the outermost valve, and centered about the longitudinal axis100. A second adjustment valve105is shown positioned between the first adjustment valve103and the third adjustment valve107, and centered about the longitudinal axis100.

The drawing includes several boundary lines that generally indicate the components associate with each adjustable valve in the response adjustment mechanism. It should be understood that this boundary line provides only a general representation, since some of the elements of the valves are shared amongst themselves.

A boundary line generally indicated by the numeral102provides a guideline boundary generally indicating the elements included to make the first adjusting valve in the response adjustment mechanism88. The valve bounded by the guideline boundary102is a type of needle valve whose construction will discussed in further detail below. A boundary line generally indicated by the numeral104provides a guideline boundary generally indicating the elements included in the second adjusting valve in the response adjustment mechanism88. The valve bounded by the guideline boundary104includes a bore106that is configured to receive the valve bounded by the guideline boundary102in coaxial relation. The valve bounded by the guideline boundary104is a type of valve that controls the flow as a function of the pressure on the valve, which in this specification, is referred to as a pressure controlled valve, whose construction will be discussed in further detail below. A boundary line generally indicated by the numeral108provides a guideline boundary generally indicating the elements included in the third adjusting valve in the response adjustment mechanism88. The valve bounded by the guideline boundary108includes an element110that is configured to receive the valve bounded by the guideline boundary102in coaxial relation. The valve bounded by the guideline boundary108is a type of valve that controls the flow as a function of the pressure on the valve, which in this specification, is referred to as a pressure control valve, whose construction will be discussed in further detail below.

Now referring toFIGS. 1,10and11, the response adjustment mechanism88is positioned in fluid communication between the port92and the port94of the shock absorber assembly10. The mechanism88is positioned concentrically to, and along a longitudinal axis100. A stem112is concentrically positioned along the longitudinal axis of100. The stem112includes a first end116and an opposite second end118with thread120formed in the outer surface114proximate to the second end120. A notch260is formed on the end116and is generally configured to allow a user to adjust the longitudinal position of the second end120using a screwdriver as an adjustment tool as will be discussed in greater detail below. The end118has conical shape or needle characteristic which is used to control the flow to and from the ports94and92during operation of the shock absorber10.

Now referring toFIGS. 10 and 12, a shaft122is shown having a first end137and an opposite second end138. A first bore126is formed concentrically within the shaft122and extends from the end137to an intermediate position between the end137and the end138. A second bore128formed concentrically within the shaft122extends from the end138to the bore126. The bore128has an inner surface132with threads134form therein. The shaft122has an outer surface124, wherein the outer surface has a plurality of steps. Threads125are formed in the outer surface124at an intermediate position between the end137and the end138. The shaft122is configured to receive the stem112so that the end116of the stem112is inserted into the bore128and further extended into the bore126. The stem112is brought further into the shaft122by engaging the threads120and the threads138together by rotating the end116using a screwdriver to lift the stem112into the shaft122until the end118is proximate to the aperture136formed through the shaft122. The amount of fluid passing between the port94and the port92may be controlled by adjusting the longitudinal position of the end118relative to the aperture136. As will be understood, the amount of flow that may be controlled using the valve112in combination with the shaft122is low and has been found to be most useful for controlling the response of the shock absorber when the motion of the shock absorber apparatus10is in a low state. One skilled in the art will readily recognize that the combination of the stem112and the aperture136in the shaft122forms a needle valve which is useful for controlling the flow of a fluid.

As best viewed by studyingFIGS. 10,25and26, a second shaft140is shown positioned concentrically, and along the longitudinal axis100of the response adjustment mechanism88. The shaft140has a first end142and an opposite second end143. A hexagonal recess152proximate to the end142of the shaft140is provided for adjustment. The shaft140further comprises a bore146located proximate to the end143. A second bore148extends from the first bore146to an intermediate location between end142and end143. The bore148has threads154formed therein. A third bore150having a diameter less than the bore148a shown positioned between the hexagonal recess152and the second bore148. The shaft140has an outer surface144which has a small taper so that the diameter of the surface144proximate to the end143is slightly larger than the diameter of the surface144proximate to the end142.

The shaft140is shown concentrically and coaxially aligned with the stem112and the shaft122. The shaft140, threadingly fastens to the shaft122by engaging the threads154on the shaft140with the threads125on shaft122. In this manner, the relative longitudinal position of the shaft140relative to the shaft122may be adjusted and set by rotating the shaft140relative to the shaft122. A spring156has a first end157and an opposite second end158. The spring156is shown inFIG. 10positioned around and generally concentric to the shaft122. The end143of the shaft140is configured to contact the end157of the spring156in force transmission relation so that the force stored in the spring156is exerted on to the shaft140. In this configuration, the shaft140provides a preload force to the spring156. The second end158of the spring156is borne by a first surface161of a first base160. Yet further, the first base160is borne by a second base182.

Now referring toFIG. 13, a bottom view of the first base160is shown. The base160has a bore164which is configured to provide a passage for the second end138of the shaft122to pass therein. In this position, the first base160is concentrically positioned around the first shaft122in sliding relation. Yet further, the first base160includes a lip163configured to concentrically position the first base160relative to the second base182.

As best seen inFIG. 10,14and15, the second base182includes a plurality of apertures183formed in the surface192as shown inFIG. 15. The surface192forms a seat configured to bear the first base160. It should be understood from the drawing that as the base160is borne by the surface generally indicated by the numeral192, the apertures183formed within the second base182are obscured by the base160. The force stored in the spring156may be adjusted by rotating the second shaft140relative to the first shaft122, thereby increasing the force transmitted to the first base. As fluid flows in response to an external force causing motion in the shock absorber apparatus10, a pressure is exerted on the first base160resulting in an opposing force which works against the force stored in the spring156. When the opposing force exerted on the first base160is sufficient to overcome the preload force stored in the spring156, the base160separates from the surface192of the second base182, opening an alternate path through the apertures183for fluids to flow having less resistance. The path for the fluid to flow in this situation, and when the shock absorber apparatus is in a compressive state, may be generally understood to occur through the second base182and a plurality of apertures generally indicated by the numeral199as shown inFIG. 10. As will be understood, the operation of the combination of the spring156, the shaft140, the first base160and the second base182form a pressure controlled valve which is useful for controlling the flow of fluid from port94to the port92, and thereby providing a means to adjust the response of the shock absorber10.

The second base182as shown inFIGS. 14 and 15is a machined element having an outer surface184, and having a first surface186and an opposite second surface188. The outer surface184is bound by the first surface184and the second surface188. The second base182also has a first concentric bore190that extends from a first intermediate position between the first surface186and the second surface188extending through to the second surface188. The first surface186has a recessed seat192formed therein. The second base182also has a second concentric bore194extending from the first surface186to a second intermediate position located between the first intermediate position and the first surface184. The second base182also has a concentric cavity196that extends from the first intermediate position to the second intermediate position as may be seen inFIG. 14.

Now referring toFIGS. 10,16and17, a screw214having a bore220formed therein is a shown having a head218which is inserted into the cavity199of the second base182. The screw214has a second end217, and an outer surface having threads216. The threads216of the screw214threadably and rotatably inserted into the internal threads of the first shaft122near the end138as shown inFIG. 10. The screw214is configured to retainingly fasten the shaft122and the second base182together. The screw214has channels219formed into the head for enhancing fluid flow in the cavity196of the second base182. In addition, these channels219are a useful for rotating the screw214into the position within the response adjustment mechanism88.

Now referring toFIGS. 10,27,28and29, a third shaft166having a first surface167and an opposite second surface168. The shaft166is substantially concentrically aligned with the longitudinal axis100of the response adjustment mechanism88. The third shaft166has a concentric bore172defining an internal surface174. The surface174is configured to engage the outer surface144of the second shaft140in fastening relation. The third shaft166also includes an outer surface170forming a shoulder having threads176formed therein proximate to the surface168. The surface168of the third shaft166is configured to transmit a preload force to a spring178. Yet further, a shoulder is formed in the surface168which serves to act as a guide for the spring178. The spring178has an aperture (not shown) which provides an opening so that the spring178is positioned around the shaft140and the spring156. The spring178may be comprised of a stack of individual spring elements as shown inFIG. 29. In a preferred embodiment, the spring elements may be of the cup spring variety, with each spring having an aperture greater than the outside diameter of the shaft140. The individual spring elements are generally indicated by the numeral258. The spring178has a first end179and an opposite second end180. The first end179of the spring178is positioned in force transmission relation to the surface168of the third shaft166. The second end180of the spring178is positioned in force transmission relation to the second base182so that the spring178is borne by the second base182.

As it may be understood from studyingFIG. 10, the second base182is borne by a third base generally indicated by the numeral202. The third shaft166imparts a preload force to the spring178by threadably engaging a housing198having internal threads to provide an axial preload force directed along the longitudinal axis100. The housing198is retained by threadably engaging a locking cup (not shown) with the outer threads on the housing198. A force is exerted upon the second base182when motion is imparted on the shock absorber apparatus10that develops a pressure difference between the port94and92. This pressure may exert an opposing force that is opposite in direction to the preload force stored in the spring178. When the opposing force is sufficient to overcome the preload force in spring178, the opposing force will cause the second base182to separate from the third base202. When the second base182separates from the third base202, a relative large fluid flow passage is created in the gap (not shown) between the second base182and the third base202allowing fluid to pass directly from the passage90(FIG. 1) out the apertures199to the port92(FIG. 1) of the shock absorber apparatus10. The amount of preload force may be preset by rotating the third shaft166by engaging the wrench flats generally indicated by the numeral264(FIG. 28) using a wrench or other suitable tool.

Referring now toFIGS. 22A,22B,23and24, several styles of the third base202that have been developed, and are indicated generally by the designations202A and202B. The third base202has a first surface203and an opposite second surface204. Yet further, the third base202has a first cavity206having an inner surface208that is bounded by the first surface203and extends to an intermediate position between the first surface203and the second surface204. The inner surface208is configured to support the outer surface184of the second base182. The third base202has a second cavity210extending from the intermediate position to the second surface204. The second cavity210defines a third surface212that is positioned proximate to the intermediate position. A plurality of apertures201are formed in the third base203and connected by an internal passage (not shown) to the plurality of apertures205formed in the third surface212. These internal passages are useful for providing return fluid flow between port92(FIG. 1) and the passage90(FIG. 1). The apertures199shown inFIG. 22Bare similar to the apertures199shown inFIG. 10and are formed in the third base202B rather than in the housing198.

Now referring toFIGS. 10 and 24, a washer or plate266is positioned adjacent to the surface212of the third base202. A spring268having a first end269and an opposite second end270is positioned with the first end269of the spring268positioned proximate the washer or plate266. The end270of the spring268is borne by a notch formed in the third base202in retaining relation. In this configuration, the washer or plate266obscures the apertures205formed in the surface212of the third base202. The pressure in the fluid from port92to the port94may exert a force on the washer or plate266in an opposite direction to a force stored in the spring268. When the force generated by the pressure in the fluid is sufficient, the spring268will allow the plate or washer266to separate from the surface212of the third base202permitting fluid to flow from the port92to the port94. In an alternate situation, when the pressure is greater at port94relative to port92, the force exerted on the plate or washer266is in the opposite direction and further forces the plate or washer266against the surface212of the third base202effectively blocking the apertures205. In this configuration, the combination of the washer or plate266, the spring268, and the shoulder of the third base202forms a check valve restricting the flow through the path formed from the aperture201to the aperture205in the third base202when the pressure is greater at the port94relative to the port92in the shock absorber apparatus10.

Now referring toFIGS. 10,18,19,20and21, a spring224is positioned concentrically along the longitudinal axis100of the response adjustment mechanism88. The spring224is helical spring having a first end that is bounded by the screw214. An opposite end of the spring224is borne by a disc226. The disc226has a first surface227and an opposite second surface228. A bore230is formed between the first surface227to an intermediate surface positioned between the first surface227and second surface228generally indicated by the numeral234. A bore or aperture232is formed into the surface234and extends through the surface228. The surface234of the disc226is configured to seat and contain an end of the spring224in force transmission relation. The outer surface235of the disc226is configured to slidingly translate within the bore190(FIG. 14) of the second base182.

A plate236is borne by the second base182in fitting relation. The plate236has a first surface237and an opposite second surface238, and a concentric shoulder240proximate to the second surface238. The plate236also has an outer concentric surface242extending from the concentric shoulder240to the first surface237. A concentric bore244extends from the surface237through the surface238. The plate236further has a plurality of apertures250and252, each having a longitudinal axis,246and248respectively, extending from the second surface238to an intermediate position between the first surface237and the second surface238. The plate236also has a plurality of bores254and256centered along the longitudinal axis of each aperture,246and248respectively, extending from the first surface237to the intermediate position.

The combination of the plate236, the disc226, and the spring224within the second base182form a baffle assembly which is useful for controlling the flow of fluid to and from port94and port92. The baffle assembly serves to provide an additional damping function useful for modifying the response of the shock absorber apparatus.

Now referring toFIGS. 10 and 30, the response adjustment mechanism88is provided with three separate user adjustments which are useful for modifying the response of the shock absorber apparatus10. A first adjuster shown inFIG. 30has a screw head generally indicated by the numeral260. The screw head260is useful for controlling the position of the stem112relative to the aperture136formed in the shaft122thereby providing an adjustment which substantially controls the response of the shock absorber104during low speed motion. A hexagonal recess generally indicated by the numeral262permits the user to change the preload of the spring156by changing the longitudinal position of the shaft140relative to the first base160. This adjustment controls the amount of force required to dislodge the base160from the second base182and is effective in substantially controlling the response of the shock absorber apparatus10during periods of medium motion. The hexagonal wrench flat264formed into the shaft266is useful for adjusting the preload of the spring178which controls the amount of pressure required to cause the second base182to separate from the third base202. By turning flat264, the shaft166is rotated relative to the second base182thereby modifying the preload force on the spring178. The adjustment realized by the flat264allows the user to set the amount of force required that must be overcome, by the fluid pressure in the shock absorber apparatus10to dislodge the second base182from the third base202. Typically, a high level of force is required to dislodge the second base182from the third base202relative to the other adjustments. In this way, the adjustment264is useful for controlling high speed motion in the shock absorber apparatus10.

Now referring toFIGS. 31,34,35A,36,37and39A, a damping valve assembly52E and associated components will now be described. A piston generally indicated by the numeral312is shown mounted concentrically to the rod22. A passage313formed in the piston312allows fluid to pass from one side of the piston313to the other side of the piston313as governed by the action of the damping valve assembly52E. A step washer308has an aperture335which forms an inside edge336. The rod22is inserted into the aperture335of the step washer308in stacking relation so that the step washer308is adjacent to the piston312. Yet further, the step washer308has an outside diameter dimension generally indicated by the numeral333and has a thickness dimension generally indicated by the numeral310. A pressure plate314has an aperture339and a diameter dimension generally indicated by the numeral337. The aperture339of the pressure plate314forms an inside edge320which has a thickness dimension generally indicated by the numeral322. The diameter dimension337of the pressure plate314is selected to be greater than the outside diameter dimension333of the step washer308. Yet further, the thickness dimension322of the inside edge320of the pressure plate314is selected so it is less than the thickness dimension310of the step washer308. In this manner, the rod22and the step washer308are inserted into the aperture339of the pressure plate314in sliding relation so that both the step washer308and the pressure plate314are adjacent to the piston312when a preload force is applied to the pressure plate to hold it against the piston312. A plate spring309having an aperture326is positioned in stacking relation around the piston rod and adjacent to the step washer308. A plurality of other plate springs444may be positioned in stacking relation one to another around the piston rod and adjacent to the plate spring309. A retaining means (not shown) is configured to fixedly hold the other plate springs444, plate spring309, and the step washer308in stacking relation to the piston312. The retaining means may include but is not limited to a sleeve, nut, shoulder of a shaft or other forms of mechanically securing elements to a rod22in stacking relation.

The pressure plate314has a ridge or ledge434and that has a thickness dimension generally indicated by the numeral436. The pressure plate314is further selected so the thickness dimension436is greater than the thickness dimension310of the step washer308. The difference between the thickness dimension436and the thickness dimension310defines an initial deflection distance of the plate spring309as the plate spring309is held in tension by the pressure plate314. This initial deflection distance is graphically represented inFIG. 38Aand is as generally designated by the numeral307. This initial deflection distance of the plate spring309generates a preload force which acts on the pressure plate314causing it to rest adjacent to the piston312as shown inFIG. 31. The amount of preload force may be selected by adjusting the difference in thickness dimension, as well as by varying the effective spring rate of the combined spring309and other springs444.

Now referring toFIG. 31, the plate spring309may be considered to have two distinct regions which are generally designated by the numerals328and329. The region329is defined as originates from the edge of the aperture326of the plate spring309and extending outwardly relative to the aperture326for a distance generally indicated by the dimension332. The dimension332may be considered to be about ⅙ of the outside diameter plate spring309. The region328is generally in bounded by the dimension generally indicated by the numeral330. The dimension328is equal to about ⅙ of the outside diameter of the plate spring309. As may be understood by a study ofFIG. 31, a portion of the region328of the plate spring309is borne by the pressure plate314and a portion of the region329of the plate spring309is borne by the step washer308.

Now referring toFIGS. 32,34,35A,36,37and39A, another damping valve assembly52F and associated components will now be described. The passage313formed in the piston312allows fluid to pass from one side of the piston313to the other side of the piston313as governed by the action of the damping valve assembly52F. One or more shims334having an aperture are positioned in stacking relation around the rod22and adjacent to the piston312. The rod22is inserted into the aperture335of the step washer308in stacking relation so that the step washer308is adjacent to the one or more shims334. The rod22and the step washer308are inserted into the aperture339of the pressure plate314in sliding relation so that both the step washer308and the pressure plate314are adjacent to the one or more shims334when a preload force is applied to the pressure plate to hold it against the one or more shims334. The plate spring309having an aperture326is positioned in stacking relation around the piston rod22and adjacent to the step washer308. A plurality of other plate springs444may be positioned in stacking relation one to another around the piston rod and adjacent to the plate spring309. The retaining means (not shown) is configured to fixedly hold the other plate springs444, plate spring309, step washer308, and the one or more shims334in stacking relation to the piston312.

The damping valve assembly52F as shown inFIG. 32will respond to control the flow of fluid traveling through the passage313as will be illustrated inFIG. 33A,FIG. 33B,FIG. 33C, andFIG. 33D. InFIG. 33A, the damping valve assembly52F is represented as a low volume of fluid (not shown) flows through the passage313in the direction indicated by the arrow317as the piston312translates in the direction generally indicated by the arrow pointed to the numeral315at a low speed. Here, the force generated by the pressure of the fluid flowing through the passage313and acting on the shims334is sufficient to slightly deflect the shims334a small amount, permitting a limited amount of fluid to flow through the passage313. However, the deflection of the shims334is small so the outer edge of the shims334do not substantially act on the pressure plate314, so that the preload force acting on the pressure plate314holds the pressure plate314in a rest position.

InFIG. 33B, the damping valve assembly52F is represented as a medium volume of fluid (not shown) flows through the passage313in the direction indicated by the arrow317as the piston312translates in the direction generally indicated by the arrow pointed to the numeral315at a medium speed. Here, the force generated by the pressure of the fluid flowing through the passage313and acting on the shims334is sufficient to deflect the shims334a moderate amount, permitting a limited amount of fluid to flow through the passage313. Further, the deflection of the shims334is sufficient so the outer edge of the shims334act on the pressure plate314so as to work against the preload force acting on the pressure plate314causing the pressure plate334to slidingly translate along the step washer308from the rest position in a direction away from the piston312.

InFIG. 33C, the damping valve assembly52F is represented as a high volume of fluid (not shown) flows through the passage313in the direction indicated by the arrow317as the piston312translates in the direction generally indicated by the arrow pointed to the numeral315at a high speed. Here, the force generated by the pressure of the fluid flowing through the passage313and acting on the shims334is sufficient to deflect the shims334a substantial amount, permitting a large amount of fluid to flow through the passage313. Further, the deflection of the shims334is sufficient so the outer edge of the shims334act on the pressure plate314so as to overcome the preload force acting on the pressure plate314which causes the pressure plate334to slidingly translate a significant distance along the step washer308from the rest position and away from the piston312.

As should be apparent to one skilled in the art, and from studyingFIGS. 32,33A,33B, and33C, the arrangement of the damping valve assembly52F as shown inFIG. 32has been shown to provide an exemplary response which is desirable in controlling the response in a shock absorber apparatus10. For example, the shims334, pressure plate314, step washer, and combination of plate springs309and444may be selected to provide a soft response characteristic during low speed operation, a firm response characteristic during medium speed operation and a soft response characteristic during high speed operation of the shock absorber apparatus10. Such a response characteristic of the damping valve assembly52F is desirable in some situations where it is desirable to provide a range of adjustability that can be attained using the response adjustment mechanism88in concert with the damping valve assembly describe herein.

Now referring toFIG. 34, a plan view of the step washer308is shown having the aperture335which is configured to slide over the outside diameter of the rod22. The surface329of the step washer308is a show inFIG. 35A. The shape of the step washer308may be modified to achieve varying desirable results depending on the type of pressure plate314and the type of shock absorber apparatus10. The step washer308is shown having a thickness generally indicated by the numeral310and has a characteristic flat surface329and an opposite flat surface331. Now referring toFIG. 35B, the step washer308has a flat surface329and a stepped corner surface321joined by a flat surface331. In the preferred embodiment, the surface331is positioned proximate to the piston312inFIGS. 31,32,33A,33B, and33C. Now referring toFIG. 35C, another variety of the step washer308having a flat surface329is shown with an angle surface323joining the flat surface331which is parallel to the surface329. The surface331is positioned proximate to the piston312in the system is shown inFIGS. 31,32,33A,33B, and33C. Now referring toFIG. 35D, the step washer308is shown having a radius corner proximate to the flat surface331. InFIGS. 31,32,33A,33B, and33C, the flat surface331would be positioned proximate to the piston312.

Now referring to FIGS. of36and37, the pressure plate314of a first variety is shown in further detail. As previously stated, the pressure plate314has an inside diameter337configured to be less than the outside diameter333of the step washer380. The pressure plate314further includes ridges or ledges generally indicated by the numeral434. Further the pressure plate314also includes valleys generally indicated by the numeral440. The pressure plate314has the ridge or ledge434which are characterized by depth dimension436. Further, the valley440of the pressure plate314is characterized by a depth dimension442. From inspection, it is evidence that the dimension436is greater than the dimension442. Furthermore, the ridge or ledge434has a width dimension generally indicated by the numeral425.

Now referring to FIG. it38A,38B,38C,38D, a cross section of the step washer308surrounded by the pressure plate314is shown. Each pressure plate314is shown with a different corner effect as will be discussed below. The pressure plate314has a flat surface generally indicated by the numeral432and the ridge or ledge of434and a second surface substantially opposite of the first surface generally indicated by the numeral438. The surface438extends in an upward or outward direction from the inner edge320(FIG. 39A) forming a radius433an reaching an apex at the ridge or ledge434. The pressure plate314also has an outside surface430which forms a corner transition. Now referring toFIG. 38B, an additional surface439having a flat characteristic is shown. Now referring toFIG. 38C, the pressure plate314has a radius corner441. Now referring to the38D, the pressure plate314has a step surface generally indicated by the numeral443. It should be understood that the examples shown inFIGS. 38A-Dare representative of some of the corner characteristics that may be applied to the pressure plate314but there are other that may be considered to fall within the scope of this specification.

Now referring toFIGS. 39A-C, further variations of pressure plate314are shown in each of the figures. InFIG. 39A, a pressure plate314has a thickness322at the inside edge formed by the aperture318. The pressure plate314has an outer edge as is indicated generally by the numeral430and has an outside diameter which he is generally indicated by the numeral316. A series of ridges or ledges and valleys are shown generally indicated by the numerals440and434. Now referring toFIG. 39B, another variety of the pressure plate314is shown with alternating ridges and valleys as generally indicated by the numeral is434and440respectively. Now referring toFIG. 39C, yet another variation of the pressure plate314is shown further having alternating ridges and valleys434and440respectively. It should be understood, that the number of ridges and valleys in the pressure plate314may be changed without altering the scope of the present invention. The ridge or ledge of the pressure plate134has a radius433formed therein that may be selected to match the natural shape of the plate spring309as it is borne by the step washer308.

The amount of preload force depends upon many factors including the thickness and number of plate springs309selected, the difference in thickness between the step washer308and the thickness of the ridge or ledge434of the pressure plate314. The plate spring392may be composed of a flexible spring-steel metal. The combination of the plate spring309, step washer308and the pressure plate314provide a versatile system for providing desirable damping characteristics in the shock absorber apparatus.

Now referring toFIG. 40, another version of a dampening valve assembly generally referred to by the designation52G is shown in a cross-sectional view. A cylinder380defines an inner bore in which a piston388is concentrically attached to a piston rod386. A pressure plate390is concentrically positioned around the rod386, and positioned in stacking relation adjacent to the piston388. A plate spring392is retained by the pressure plate390. A helical spring422has a first end424and an opposite second end423. The helical spring422is positioned concentrically around the rod386. The end424of the helical spring424is borne by the plate spring392in flexing relation. The end423of the helical spring422is borne by a retainer426. In this arrangement, the pressure plate392is slidingly positioned around the rod386, and is configured to allow fluid to flow through the piston388through passages (not shown) when the pressure in the fluid flow acts on the pressure plate in a suitable manner to overcome the preload force of the plate spring392and the helical spring424.

Now referring toFIGS. 42,43, and44, the pressure plate390is shown having a center396and an aperture408. The aperture408is configured so that the pressure plate may be positioned around the rod386in sliding relation. The pressure plate390includes a base surface394and an opposite floor surface404. Further, the pressure plate390has rim generally indicated by the numeral402extending in a perpendicular direction from the base surface394. The distance between the planes of the floor surface404in the base surface394constitute a thickness dimension generally indicated by the numeral406. A plurality of shelves of a first type414A and a second type414B have a first surface410an opposite second surface412. Each shelf,414A and414B, has a width dimension generally indicated by the numeral416and418respectively.

Now referring toFIGS. 41,45,46, and47, the plate spring392is shown having an aperture446and a flat surface448. The plate spring392is retained by the pressure plate390by arranging the spring so that a portion of the plate spring392is supported by the top surface410of the shelves414A. The plate spring392is retained by the surface412of the shelves414B. In this configuration, the plate spring392is retained by the pressure plate390, and provides a preload force.

The amount of preload depends largely upon the thickness and number of plate springs selected for an application. The preload may also be set by the depth of the step. The Plate spring392may be composed of a flexible spring-steel metal. The combination of the plate spring392and the pressure plate390provides a versatile system that flexes the plate spring392in the middle and with a preload to create firmness.

Operation

The operation and of the present invention is believed to be readily apparent and is briefly summarized in the paragraphs which follow.

A shock absorber apparatus10including a housing12including a first end18and a second end14opposite the first end18. The housing12has a bore24. A piston36is disposed in the bore24proximate the first end18and is configured to translate within the bore24responsive to external forces. Another piston38is disposed in the bore24proximate the second end14and is configured to translate within the bore24responsive to external forces. The piston36is coupled to a piston rod22. The piston rod22is partially disposed in the housing12proximate the first end18and translates into and out of the housing12. The piston rod22includes a mounting element distal from the piston38configured to mount to the wheel of a vehicle. The housing12includes a mounting element16proximate the second end14and configured to mount to a vehicle chassis.

An adjuster or response adjustment mechanism88is coupled to the housing12proximate the second end14and is configured to adjust the flow of a damping fluid370disposed in the housing12. The adjuster or mechanism88may include modified biasing members having large biasing ranges (e.g., 1500-4000 psi). The adjuster or mechanism88can include at least one of a low speed adjustment portion having elements indicated by the boundary102(FIG. 9); a mid speed adjustment portion having elements indicated by the boundary104(FIG. 9); and a high speed adjustment portion having elements indicated by the boundary108(FIG. 10).

The low speed adjustment portion can include a needle flow controller having members112and122(FIG. 10). The mid speed adjustment portion can include biasing members140,156, and160(FIG. 10) configured to control damping fluid flow. The high speed adjuster portion can include high resistance biasing members166,178, and182(FIG. 10) configured to control damping fluid flow. The damping fluid flows through and around the second piston38and first piston36and optionally may flow through grooves356in the housing. The cylinder12may have grooves356formed along the portion proximate the first piston36. The grooves356enhance the damping fluid flow around the piston36. The groove356may be tapered along the length of the cylinder12to allow for a varying groove depth along the length of the groove. The tapered groove can provide a progressive flow area resulting in a progressive dampening effect.

The damping fluid370is configured to dampen the translation of the second piston38and first piston36within the bore24. A damping valve assembly52E,52F, or52G may be coupled to at least one of the second piston38and the first piston36.

A bottoming needle or needle assembly98is adapted to be insertable into a bore66in the rod22and is configured to control the flow of dampening fluid370through or past the piston38at a predetermined location in the stroke342of the piston38. The diameter of the first internal bore may be reduced to accommodate a reduced second piston38size.

Yet further, the shock absorber apparatus10has a first cylinder12defining a first internal bore24closed by a first end wall18and an opposite second end wall14, and has a first port94connected in fluid transmission relation to the first internal bore24. A second cylinder81defining a second internal bore82closed by a first end wall81and an opposite second end wall83, and further comprising a second port92connected in fluid transmission relation to the second internal bore79. A response adjustment mechanism88is located adjacent to the second cylinder78, and connected in fluid transmission relation between the first port94and second port92. The response adjustment mechanism88further comprises three or more adjustment operators260,262, and264which are operable to direct the fluid flow between the first port94and the second port92.

The response adjustment mechanism88is located in fluid transmission relation between the first port94and the second port92. The first and second pistons,36and38respectively, translate through the internal bore24of the first cylinder or housing12in a direction generally indicated by the arrow344(FIG. 3), causing a pressure to develop in thee fluid370which causes fluid to flow from port94through the passage of90and into the response adjustment mechanism88and out to port92. This direction of flow is understood as compressive flow when the flow transfers from port94to port92.

The fluid94flowing through the passage90encounters the third base202of the response adjustment mechanism88and the second base182of the response adjustment mechanism88. As can best be understood from inspection ofFIG. 10, a fluid may enter through a bore or plurality of apertures in the late236. If this flow of fluid is characterized as being low in volume resulting from a low speed motion of the rod22, the disc226remains in the position shown inFIG. 10seated against the plate236. In this low flow situation, the fluid flows through the concentric bore224in the plate236into the bore190in the second base182and proceeds through the internal bore220of the screw214to the stem112which has a needle formed on the end118which is configured at least partially enter the bore220of the screw214. Therefore, the fluid entering the response adjustment mechanism88at a low flow volume may flow out the aperture formed in the shaft122as indicated by the numeral136(FIG. 12). As the fluid exits the aperture136of the shaft122its flows through an aperture or a plurality of apertures199formed in the housing198or alternatively in an alternate version of the third base202B (FIG. 22B). The fluid exiting the apertures199flows through the port92and into the chamber86causing the piston80to translate within the second cylinder78and compress the compressible fluid contained in the chamber84.

Again referring toFIG. 10, the pressure between the port94and the port92may be considered at a medium pressure when the rod22translates in a direction generally indicated by the arrow344(FIG. 3) at a medium speed. At the medium pressure, the preload on the spring224may be selected so that the force generated on the disc226by the medium pressure causes the plate to separate from the plate236as will be discussed further below.

As pressure from the fluid encounters the plate236positioned in the second base182, some of the pressure will be transferred to the disc226via openings or passages or aperture formed in the plate236and designated as250,252,254and, in256(FIG. 20,21). With sufficient pressure to overcome the preload force of spring224, as may occur during medium speed events, the disc226will separate from the plate236, thereby allowing a greater volume of fluid to flow. After entering the bore190and the cavity196of the second base182, the fluid exerts a pressure upon the first base160by transmitting this pressure through a passage formed in the cavity196of the second base182and leading through the aperture is183(FIG. 15) to exert pressure on the surface of the first base160. When the pressure upon the first base160is sufficient to overcome that preload force that is stored by the spring156, the first base detaches or dislodges from the second base182providing a fluid passage whereby fluid flows from the cavity196of the second base186out through the apertures183formed in the of the second base186, and exits outwardly through the apertures199as previously discussed which are positioned in fluid communication with the port92allowing the incompressible fluid to flow into the chamber86causing the piston80to displace and compress the compressible fluid82in the chamber84.

The preload force governing the fluid flow when the speed of the shaft is translating at medium speed in the direction generally indicated by the arrow344, is adjusted by turning the internal hexagonal recess152with an Allen wrench as an adjustable means to modify the preload on the spring156.

Yet further, in a situation when the rod22is translating at a high speed in the direction generally indicated by the arrow344inFIG. 3, the pistons36and38work to increase the pressure of the incompressible fluid proximate to port94and through the passage90. This increased pressure is propagated to the third base202and the second base182. The pressure generated in the fluid during a high speed motion of the rod22, generate a force on the exposed surface of the second base182. This force may be sufficient to dislodge the second base182from the third base202if the force from the fluid is greater than the preload force stored in spring178. When the force of the fluid is sufficient to overcome the preload force stored in the spring178, the second base182is dislodged from the third base202, providing an opening that forms a new flow passage that is defined by the surface184of the second base182and the surface208of the third base202. As may be seen inFIG. 10, the size of this passage is large compared to the other passages in the low and medium speed situations, and allows for a much higher volume a fluid to flow through the response adjuster mechanism88.

The fluid that flows through the passage formed a between the second base182and third base202exits through the apertures199propagating to the port92to enter the chamber86which displaces the piston80to further compress the gas contained in chamber84. The amount of preload force required to be overcome by the force generated by the fluid on the second base182, to provide the passage between the second base182and the third base202maybe adjusted by rotating shaft166using the wrench flats264(FIG. 30) to adjust the longitudinal position of the shaft166relative to the third base202.

Now considering the situation where the rod22travels in a direction generally indicated by the arrow347shown inFIG. 3, thereby causing a returning travel of the Pistons36and38, a return flow of incompressible fluid will travel from port92through the as response adjustment mechanism88and through the passage90through port94into the chamber44. Referring again toFIG. 10, there are to passages for the returning fluid whose operation will now be discussed briefly.

A first passage is notes as the fluid travels from port92having a low pressure, the fluid may travel through the apertures199into the aperture136of the shaft122to encounter the stem112and the needle portion thereof of the end118(FIG. 11). Then depending on the location of the needle portion118relative to the bore220of the screw214, a fluid of low pressure will flow through the bore220through the screw214into the cavity of the second base182through the aperture formed in the disc226and through the concentric aperture of the plate236generally indicated by the numeral244. The fluid is then the able to travel through the passage90to the port94and into the chamber44.

Another fluid passage through the response adjustment mechanism88allows fluid to flow from port92through passage90to port94will now be discussed. In this situation, the apertures201formed in the third base202connect to internal channels or passages which are connected to the aperture205(FIG. 24). The fluid flowing from the apertures205in the third base202may generate a pressure against a washer266which is shown in a position blocking the flow from the apertures205. When the pressure exerted by the fluid contained in the apertures205is sufficient to overcome the preload pressure stored by the spring268, the washer266becomes dislodged from the surface212of the third base202allowing fluid to flow out of the apertures205out to the passage90to port94which is connected to the chamber44.

Yet further, the shock absorber apparatus10, has a first cylinder12defining a first internal bore24has an internal diameter277, and closed by a first end wall18, and is further closed by an opposite second end wall14, and further has a first port94connected in fluid transmission relation to the first internal bore24. A rod22has a first end73and an opposite second end64, and wherein the rod22movably extends into the first internal bore24through an aperture23formed in the first end wall18so that the second end64of the rod is positioned concentrically within the first internal bore24, and so that the first end of the rod73is positioned outside the first internal bore24. A first piston36is fixedly attached to the rod22at an intermediate position located between the first and the second end,73and64respectively, of the rod22, and positioned concentrically within the first cylinder12. A second piston38is fixedly attached to the rod22proximate to the second end64of the rod22, and is positioned concentrically within the first cylinder12. A second cylinder78defines a second internal bore79closed by a first end wall81and an opposite second end wall83, and further has a second port92connected in fluid transmission relation to the second internal bore79. A response adjustment mechanism88is located adjacent to the second cylinder78, and is connected in fluid transmission relation between the first cylinder port94and the second cylinder port92, and wherein the response adjustment mechanism88is configured to provide three or more adjustments260,262, and264for tuning the response of the shock absorber system10.

Furthermore, a shock absorber apparatus10, has a housing12comprising a first internal bore345having a diameter348, and includes a second internal bore346having a diameter350. The housing12is closed by a first end wall354, and further closed by an opposite second end wall353. A rod22has a first end73and an opposite second end64, and wherein the rod movably extends into the first and/or second internal bore345and346respectively, through an356aperture formed in the first end wall354so that the second end64of the rod22is positioned concentrically within the first internal bore345or second internal bore346, so that the first end73of the rod22is positioned outside the housing12. A first piston36having a diameter274is fixedly attached to the rod22at an intermediate position located between the first end73and the second end64of the rod22, and is positioned within the first internal bore345in sliding relation. A second piston38, having a diameter279is fixedly attached to the rod22proximate to the second end64of the rod22, and positioned within the first and/or the second internal bore345and346respectively, in sliding relation. The diameter274of the first piston36is approximately equal to the diameter348of the first internal bore345, and the diameter279of the second piston38is approximately equal to the diameter350of the second internal bore346. In addition, the diameter279of the second piston38is less than the diameter274of the first piston36.

Yet further, the piston rod22has a longitudinal axis, and an external surface, and a bore66formed concentrically therein. The piston rod22has one or more of apertures366formed within the piston rod22and extending from the external surface of the piston rod22into the bore66of the piston rod22to form a fluid passage. The first piston36is configured to translate within the first cylinder bore345in response to an external force; a second piston38is configured to translate within the first cylinder bore345, and in the second cylinder bore346, and in response to the external force. A needle assembly96is configured to enter the bore66of the piston rod22as the second piston38nears the second cylinder bore346.

Yet further, the shock absorber apparatus10, has a housing10, and a cylinder bore24enclosed by the housing, and further has a longitudinal axis272. A rod22is substantially positioned concentric to, and along, the longitudinal axis272of the cylinder bore24, and is partially positioned within the cylinder bore24. A piston388is fastened to the rod22, and is slidingly positioned within the cylinder bore24. A pressure plate390is slidingly positioned on the rod22, and is positioned adjacent to the piston388. Wherein, the plate spring392is retainingly mounted to the pressure plate390.

And still further, the invention includes, a shock absorber apparatus10a cylinder bore24enclosed by the housing12, and having a longitudinal axis272. A rod22having a first end64and an opposite second end73, and wherein the rod22is substantially positioned concentric to, and along, the longitudinal axis272of the cylinder bore24, and wherein the first end64of the rod22is positioned within the cylinder bore24. A piston312is fastened to the rod22in stacking relation, and positioned within the cylinder bore24. A step washer308has a first thickness dimension310, and is positioned on the rod22in stacking relation, and positioned proximate to the piston312. A pressure plate314has an outside diameter316, and has an aperture339formed therein, and wherein the pressure plate314has an inner edge320bounded by the aperture339, and wherein the inner edge320has a second thickness dimension322, and wherein the pressure plate314is positioned around the step washer308in sliding relation so that the step washer extends through the aperture339of the pressure plate314. A plate spring309has an outer edge311, and has an aperture326formed therein. The plate spring309has a first region328bounded by the outer edge311of the plate spring309and extends inwardly by a first distance330. The plate spring309has a second region329bounded by the aperture326and extends outwardly by a second332. In operation, a portion of the outer region328of the plate spring309is borne by the pressure plate314, and further a portion of the inner region329of the plate spring309is borne by the step washer308. In this case, the first thickness dimension310is greater than the second thickness dimension322. Also, the first distance330and the second distance332are less than the outside diameter316of the pressure plate314divided by 6.