MXPA97006567A - Shock absorber sensitive to acceleration and flu - Google Patents

Abstract

The present invention relates to an acceleration sensitive damper, connected at one end to the chassis of a vehicle, and at the other end to a vehicle wheel, characterized in that it comprises: a tubular housing for connection to a portion of a vehicle a piston assembly in the housing comprising a piston separating the housing in an upper chamber and a lower chamber, and a piston rod for connection to another portion of the vehicle, one portion being the chassis of the vehicle and the other portion is a wheel of the vehicle, a means for passing the buffer fluid between the upper chamber and the lower chamber with a restricted flow velocity during compression of the shock absorber, a means for passing the absorbing fluid between the upper chamber and the chamber lower with a restricted speed of flow during the extension of the buffer, a first gate or port to provide the flow of the fluid from the lower chamber to the upper chamber, a second gate or port to provide fluid flow from the upper chamber to the lower chamber, an inertial mass movable in the damper to open the first gate when the acceleration of the vehicle wheel is greater that a predetermined amount to increase the flow of fluid between the upper chamber and the lower chamber, and a means to apply sufficient fluid pressure to the inertial mass, to maintain the inertial mass in an open gate position in response to fluid flow between the cameras

Description

SHOCK ABSORBER SENSITIVE TO ACCELERATION AND FLOWS BACKGROUND OF THE INVENTION The present invention relates to dampers for vehicles that are typically mounted between the wheels and the chassis of a car, truck, motorcycle, etc. The invention relates to a shock absorber whose damping characteristics change according to the acceleration of its component parts, and most importantly to the downward acceleration of the wheel of the vehicle. More specifically, it refers to the control of fluid flow linked to the sensitivity to acceleration in the damper. The hydraulic shock absorbers are universally used in automotive. Each wheel is linked to the chassis or structure of the vehicle through a spring so that the hills or bumps in the road are not transmitted directly to passengers or cargo. However, a spring alone would still result in a rough ride. Consequently, dampers are mounted in parallel with the springs in order to dampen the accelerations applied to the chassis from the wheel. Most shock absorbers are designed to have a certain operating characteristic or load-speed curve that meets the demands of different paths. The characteristics suitable for driving on a relatively smooth road, however, may not be so in the cases REF: 25534 in which the wheels can be found with hills or wells of short extension. . In the art, shock absorbers are known which respond to accelerations of the vehicle wheel. One such method implemented in a standard cylinder-piston system allows dynamic adjustment of the valves and orifices to control the flow of hydraulic fluid from one end of the cylinder to the other end through the piston in response to ground defects. . Such pressure sensitive dampers have shown remarkable ability to increase the functionality of the vehicles spun with such a spring or driver, however it is still desirable to provide an additional improvement in the acceleration responsive damper.

SHORT_DESCRIPTION_ OF _LA_INVENTION Therefore, there is provided in the practice of this present invention in accordance with currently preferred embodiment, an acceleration sensitive damper having a tubular box and a piston assembly in the box, dividing the box into an upper chamber and a lower chamber. . The shock absorber is connected to one end of the chassis of one vehicle and the other end to a wheel of the vehicle. The fluid can pass between the upper and lower chamber with a restricted flow velocity during an extension or compression of the damper. There is a first port to increase the flow of fluids between the chambers and a movable inertial valve to open the first port when the downward acceleration in the vehicle wheel is greater than a predetermined amount. In addition, the acceleration sensitive damper has a means for diverting the inertial valve to its open position in response to fluid flow from the lower chamber to the upper chamber. The acceleration sensitive damper also provides a means to close the first port with the inertial valve as soon as the flow in the first port is suspended. In a preferred embodiment, the inertial valve is mounted on the piston assembly to normally maintain the first closed port and to open the port during extension of the shock absorber, i.e., the acceleration of the vehicle wheel downwardly. The first port is kept open having a first restricted flow path roTi and below the first port which has a flow area smaller than the flow area of the first port when the first port is open. The first port is closed to have a lip formed with the inertial valve extending to the second port on which a downward force is exerted during fluid flow from the upper chamber to the lower chamber. The magnitude of the downward pressure is further increased through an ascending restricted flow passage having a flow area lower than that corresponding to the second port. In another embodiment of a single tube damper, the inertial mass is mounted on the piston in order to keep the port normally closed and to open it before the extension of the damper, that is, downward acceleration of the wheel. The port is kept open through a restricted flow passage below the port that has a lower opening speed than the port when it is partially open. In an embodiment for a double tube damper, a sleeve-type inertial mass is mounted in a fluid reservoir surrounding the chambers in order to maintain a port between one of the chambers and the normally closed reservoir, and to open it before the chamber. descending acceleration of the vehicle wheel. The port is kept open through a restricted flow passage below it that has a flow area smaller than that corresponding to the port during at least part of the displacement of the inertial mass between the position of the open port and the position of the port closed.

BRIEF DESCRIPTION OF THE DRAWINGS These and other features and advantages of the present invention will be better understood with reference to the following detailed description, in conjunction with the accompanying drawings in which: Figure 1 illustrates in longitudinal cross-section an acceleration responsive damper constructed in accordance with the principles of the present invention at a time when acceleration of the vehicle wheel does not occur; Figure 2 is a partial cross-sectional view of the assembly of the pist during the descending acceleration of the wheel of the vehicle, the valve being open to acceleration; Figure 3 illustrates in longitudinal cross-section a piston for an acceleration responsive damper wherein the left side of the drawing shows the damper when there is no acceleration of the vehicle wheel, and the right side of the drawing shows the damper during descending acceleration of the wheel; and Figure 4 is a semi-schematic, fragmentary longitudinal cross-section of a double-tube damper with a flow-sensitive inertial mass.

DETAILED DESCRIPTION The first two drawings illustrate a piston for a single tube damper responsive to acceleration and flow. The piston is located on a piston rod 10 connected to the wheel (not shown) of a vehicle. The piston is mounted on the hollow cylindrical body 11 of the damper, which is attached to the structure or chassis (not shown) of the vehicle. The piston divides the interior of the cylinder 11 in the lower chamber 12 below it and the upper chamber 13 above it. The rest of the shock absorber, including the means of connection to the vehicle, is conventional, its illustration being necessary for the purpose of understanding the invention. It should be understood that the references are made to an upper chamber and a lower chamber, since this is the normal mode of installation of the shock absorber in a vehicle. Alternatively, in some systems, it is possible to reverse it. When mounted in accordance with the illustration, the displacement of the piston in the downward direction occurs before the extension of the shock absorber, for example when the wheel separates from the vehicle as a result of a well in the ground or when it bounces due to compression. Alternatively, upon compression of the shock absorber, the wheel and the piston move upwardly in the cylinder.

The piston is composed of a hollow piston 14 threaded on the upper end of the hollow piston rod 10. A captive screw 15 prevents the piston from disengaging from the rod. A hollow inertial valve seal 16 is threaded into a smaller diameter end of the piston. A captive screw (not shown) in a diagonal hole 20 in the inertial valve detent bites the end of the piston in order to prevent the detent from disengaging from it. The perimeter of the piston is sealed to the interior of the cylinder through a circumferential bevelled anti-wear band 17 made of polytetrafluoroethylene or similar material. The anti-wear band rests on a ring 0 18 which acts as a "spring" in order to move said band against the inside of the cylinder. An adjustment rod 19 extends through the rod and the piston. The upper end of the adjusting rod is hollow and closed by a threaded plug 21. The outer part of the upper end of the adjustment rod is hexagonal and fits into a hexagonal hole of a rebound adjuster 22 which is held in the retainer inertial valve by means of a snap ring 23. An annular rebound valve 24 has a portion of an upper diameter that bears against an anchor within the inertial valve retainer being displaced towards said anchor by means of a spring 26. On the outside of a reduced diameter portion of the rebound valve there are four slots that extend diagonally 27. During extension or rebound of the shock absorber, the piston moves in a downward direction in the cylinder, raising the pressure in the lower chamber and decreasing it in the upper chamber. This causes the fluid to pass through the radial openings 28 in the piston rod and the additional radial openings 29 communicating with the hollow interior of the adjusting rod. The increased pressure of the fluid against the rebound valve 24 moves the valve upwardly against the rebound spring, the diagonal slots 27 moving with respect to the anchor in the retainer so that the fluid can pass through the valve and the orifices 31 through the valve. The rebound adjuster on the upper end of the piston. It is also observed that the change of position of the threaded rebound adjuster also modifies the total displacement of the rebound valve. This affects the maximum opening of the grooves adjacent to the anchor and consequently the speed of fluid flow through the valve. As mentioned, the end of the adjusting rod 19 is hexagonal and fits into a hexagonal hole in the rebound adjuster. The rebound adjuster is threaded into the inertial valve retainer. Thus, the rotation of the adjusting rod can displace the rebound adjuster longitudinally in the fillets. This modifies the force on the rebound spring. The adjustment rod extends through the lower end of the shock absorber for the purpose of adjusting the rebound according to the aforementioned patent. An annular compression valve 32 fits around the adjusting rod and has an anchor that abuts against the end of a smaller diameter portion of the rebound valve 24. A smaller diameter portion of the compression valve fits within a rebound valve sector. The smaller diameter portion of the compression valve has diagonal grooves 33 on the outer surface facing inwardly of the compression valve. This valve is moved to the closed position against the rebound valve through a compression spring 34. The other end of the compression spring. it rests on a compression adjuster 36 that fits on the adjusting rod and sits on the anchor 37. The compression adjuster is wedged between said anchor and a snap spring 40.

To adjust the opening force of the compression valve, adjust the adjustment rod longitudinally. As the compression adjuster separates from the compression valve, the force on the compression spring 34 decreases, reducing the opening force of the valve. On the contrary, as the adjusting valve moves upwards towards the valve, the opening force increases. Four longitudinal extensions 39 on the compression adjuster are attached to the bottom of the compression valve. When the adjustment rod is in the upper end position it actually rests against the end of the compression valve, preventing its opening. This achieves the maximum rigidity of the shock absorber in compression. This adjustment also modifies the displacement of the compression valve. When the adjustment rod moves down, the extensions are separated from the end of the compression valve 32 whereupon it can be opened. Typically, a 2.5 mm longitudinal displacement is adequate to adjust to the milder compression resistance. Thus, the compression adjuster sets the opening force by, compression for the compression valve and the displacement thereof. The limitation of the displacement of the valve regulates the opening of the slots 33 and measures the amount of fluid that can pass through the compression valve. When the vehicle encounters a spine, for example, by compressing the shock absorber, the fluid pressure in the upper chamber 13 is greater than the pressure in the lower chamber. The fluid in the damper flows through the holes 31 in the rebound adjuster, through the central hole of the rebound valve 24, through the slots 33 in the compression valve, through the openings (not shown). illustrated) between the extensions 39 in the compression adjuster, through the radial holes 29 in the hollow end of the adjustment rod, and through the holes 28 in the piston in the direction of the lower chamber.

The compression spring 34 which moves the compression valve 32 against the rebound valve 24 has a sufficient displacement which keeps the compression valve closed even when the rebound valve moves to its open position. The pressure from the lower chamber during rebound also helps keep the compression valve closed. The system with an annular rebound valve and a coaxial compression valve partially nested within it provides a very compact valve arrangement for the limited space available in a shock absorber. In this system, the compression valve and the rebound valve are confronted, the compression valve being displaced to open the rebound valve. The rebound spring 26 has a constant greater than the compression spring 38 so that in the absence of differential pressure through the piston, the rebound valve remains closed against the anchor in the inertial valve retainer and the compression valve closed against the end of said rebound valve.

The edge of the anchor in the inertial valve retainer cooperates with the diagonal slots 27 in the rebound valve for the purpose of measuring the flow through the valve during the rebound or extension of the damper. As the rebound valve separates from the anchor as the pressure in the lower chamber increases, the slots progressively open allowing more fluid to pass through the valve. It is evident that the same result can be achieved with diagonal grooves in the inertial valve retainer and a cylindrical surface which cooperates on the external part of the rebound valve. Similarly, the lower diameter end of the rebound valve cooperates with the diagonal grooves 33 in the compression valve to measure a flow during compression of the shock absorber. When the compression valve is in its maximum nested position within the rebound valve, the slots 33 are completely closed and consequently no fluid passes through the valve. As the compression valve separates from its nested position, the area of the slots through which fluid can pass increases progressively. Limiting the displacement of the compression valve before finding the extensions 39 on the compression adjuster determines the maximum flow velocity of the fluid and the compressive stiffness of the shock absorber. If desired, the slots can be provided inside the rebound valve. The force of the compression valve on the rebound valve tending to open it varies according to the adjustment of the opening force of the compression valve. Thus, when you want to adjust the stiffness of the shock absorber, it is better to adjust the compression rather than the bounce. It is also convenient to have an "escape" pressure in the case of rapid compression of the shock absorber. For this purpose, a displaced disc valve 41 is placed against the lower part of the piston through a disk retainer 42. In the case of a substantial increase in the pressure in the upper chamber, the fluid passes through the diagonal passages 43 and opens the disc valve in order to allow direct fluid flow from the upper chamber to the lower chamber.

An important characteristic of the shock absorber is the sensitivity to acceleration. This is achieved through a rather large inertial valve 46 that fits into an extension of smaller diameter 47 of the piston. Between the external diameter of the extension of the piston and the internal of the inertial valve a firm insertion takes place in order to minimize the filtrations of fluid when the valve is closed. For example, the diametral spacing ranges approximately between 60 and 65 micrometers. 4 Ports 48 are provided which extend radially through the extension of the piston in a position adjacent the inner surface of the inertial valve 46 when closed as illustrated in Figure 1. In the illustrated embodiment the ports are turned diagonally to Through the wall of the extension 47 for the purpose of avoiding interference during this process with a flange 49 extending the circumference of the upper end of the piston. In an exemplary embodiment, four ports are provided, each with an area of 20 square millimeters, or a total flow area through these "ports of 80 square millimeters." In the case of downward acceleration of the wheel to which is linked to the piston rod, the piston accelerates in a downward direction.As a consequence of the inertia of the inertial valve, it tends to remain in a fixed position in space and the piston separates from it. The inertial valve moves in an upward direction (relative to the piston) until it fits in the inertial valve retainer 14. When moving to this upper or opening position, according to Figure 2, its lower portion no longer obstructs the ports to As a result, the fluid from the lower chamber can pass through the radial ports 28 in the hollow piston rod, the check valve 51, and the ports 48 towards the upper chamber. Thus, when the descending acceleration of the wheel exceeds a certain amount, the inertial valve is fully opened to allow relatively rapid fluid flow from the lower chamber to the upper chamber. Of course, the resistance to the extension of the vehicle's spring and the wheel is reduced, allowing it to descend quickly while maintaining contact with the road surface. An optional feature is given by a light spring 52 between the upper face of the piston and the inertial valve.The spring is selected such that when the inertial valve is completely closed as illustrated in Figure 1, the spring supports only 80 This means that the gravity closes the inertial valve against the force of the spring, bringing the lower end of the valve against the upper face of the piston according to Figure 1. Likewise, when the spring is Fully extended as shown in Figure 2, the inertial valve being against its retainer, it supports between 10 and 20% of the weight of the same.The incorporation of this spring assists in the lifting of the inertial valve and stimulates a rapid opening of the same A relatively light spring 53 holds the check valve 51 closed. The check valve allows flow between the lower chamber and the upper chamber when the ports 48 in the piston are opened through the displacement of the inertial valve. The check valve, however, closes quickly and prevents reverse flow in the case of compression before the complete closing of the inertial valve. The inertial valve provided by the inertial mass is in the piston linked to the wheel of the vehicle. This is convenient since it is desired to keep the shock absorber "soft" when activated by the acceleration of the wheel, but "rigid" when the acceleration of the vehicle body occurs. Thus, the shock absorber allows the wheel to move easily to follow the ground, as for example, when it falls in a pothole, without transmitting much acceleration to the body of the vehicle. On the other hand, if the body tried to move with respect to the wheel, it is convenient that a slight deflection occurs in the shock absorber so that the acceleration is effectively resisted and the passengers do not perceive a great movement. It has been found that it is convenient to keep the inertial valve in the open position (according to the illustration in figure 2) even after decreasing the acceleration. Accordingly, a restricted flow passage is provided below ports 48 controlled by the inertial valve in order to move it to its opening position as fluid flows from the lower chamber to the upper chamber. This restricted flow passage is provided through a small annular lumen between the internal diameter of the flange 49 and the outer circumferential surface 54 on the inertial valve. When the inertial valve is completely closed as illustrated in Figure 1, this space, by way of example, between the inner part of the rim and the outside of the inertial valve is 0.6 mm. The relative areas and spacings of ports 48 and the restricted flow passage between the flange and the inertial valve are such that the passage has a smaller area than the ports when they are open, with the exception of a short distance at the time in which the ports are almost closed. Thus when the inertial valve is fully or partially open, the cross-sectional area for the flow of fluid through the restricted passage is smaller than the cross-sectional area for the flow of fluid through the ports. As a consequence of this restricted flow passage under the ports, the pressure is greater in the area between the piston and l * to the inertial valve than in the upper chamber 13. This hydraulic pressure differential between the lower end of the inertial valve and its upper end displaces the acceleration sensitive valve to the open position. The outer edge of the lower end of the inertial valve has a radius 56, while on the internal part of the upper sector of the flange on the piston there is a radius 57. The restricted flow passage for controlling the downward flow from the ports has an area controlled by the space between the flange and the inertial valve until near the upper end of the displacement of this valve when the two radii begin to enlarge the distance between these elements, and increase in flow area. Even when fully open as illustrated in Figure 2, the flow area through the restricted flow passage between radios 56 and 57 is less than that through the ports. Conversely, when the inertial valve begins to close, the area of the restricted flow passage decreases during part of the stroke and then remains essentially constant. As the inertial valve moves from its open position to its closed position, the pressure in the space between the end of the inertial valve and the piston face increases as the fluid flows through the ports and passage of restricted flow from the lower chamber to the upper chamber. The increased pressure retards the closing of the valve, thereby facilitating the rapid flow of the fluid over a longer period. As it has been suggested, the check valve 51 inhibits reverse flow in the case of compression before the inertial valve closes. Radial space and radii help determine the pressure in the space under the inertial valve and consequently, the tendency of the valve to remain open. It has been found that limiting the radial space can cause the inertial valve to remain open for too long a period. Increasing this space, the inertial valve closes sooner. The spacing mentioned by way of example is suitable for a rally car that encounters extremely uneven terrain at high speed, making it necessary for the damper to respond quickly. For a street car with which the loins and potholes are faced at a lower speed, it is preferable to use a smaller spacing in order to cause a slower closing of the inertial valve. The adjustment forms described above are suitable for expensive race cars for example, but probably too expensive for most mass-produced vehicles. However, these forms of adjustments can be used in development work to determine the appropriate parameters for a given vehicle. These parameters can then be duplicated in dampers with fixed parameters for the vehicles in series. Figure 3 is a partial longitudinal cross-sectional view of the piston and the inertial valve of another embodiment of a shock absorber responsive to acceleration and fluid flow comprising an additional feature, namely: a means for quickly closing the inertial valve before the generation of reverse flow. Part of the structure illustrated in Figure 3 is similar to that described above and illustrated in Figures 1 and 2. Accordingly, the same reference numbers are used to designate the parts. Figure 3 differs from Figures 1 and 2 in that the shock absorber is shown on the left, there being no acceleration of the vehicle wheel in the downward direction and on the right the same to the shock absorber under acceleration in the downward direction of said wheel. In this illustration, part of the piston structure is dispensed with, since it is not necessary to understand the invention. The structure omitted is similar to that disclosed in Figures 1 and 2.

Thus, Figure 3 illustrates a piston 14 on a piston rod 10. Instead of having a sleeve 47 integral part of the piston, an intermediate sleeve 60 is placed between the piston and the longitudinally extending upper sleeve. These parts are adhered to the piston through a threaded nut 70 in the bar. In part, this is done for the purpose of facilitating the turning of the internal structure over the larger diameter portion of the piston and the radial ports 48 for the flow of fluids through the piston assembly. Figure 3 further illustrates an inertial mass 46 mounted on the piston. Guide pins 71 on the piston support coil springs 72 that displace part of the weight of the inertial mass in order to accelerate the opening of the inertial valve. A displaced disc valve 41 is provided on the underside of the piston and another 73 on the upper part of the assembly. The upper disc valve 73 has suitable deflection characteristics to dampen the movement of the body imposed on the shock absorber. In the embodiment illustrated in Figure 3 the restricted flow passage below the fluid ports 48 is provided through a small annular lumen between the lower edge 61 of the inertial mass 49 and an anchor 62 in the piston 49, when the Inertial valve is open. The "areas and relative spaces of ports 48 and the annular restricted flow passage are such that the latter has a smaller area than the ports when the inertial valve is open.Thus when the inertial valve is open, the area In cross-section for the flow of fluid through the restricted flow passage is less than the cross-sectional area for the flow of fluid through the ports.As a consequence of this restricted flow passage below the ports, the pressure is greater under the inertial valve 46 that in the upper chamber 13. This hydraulic pressure difference due to the restricted flow passage displaces the acceleration-sensitive valve 46 to its open position.This displacement in the upward direction continues as long as there is fluid flow even after that the acceleration has concluded - When the inertial mass is displaced in an upward direction with respect to the piston or as a consequence of the acceleration, and is retained in its upper end position due to the flow of fluids, the lower edge 61 of said inertial mass is located above the anchor 62 on the piston and the cross-sectional area of the fluid passage is more larger than when the edge and the anchor are in adjacent position. Thus, as the inertial valve begins to descend from its upper end position, the flow area of the restricted flow passage decreases, thereby increasing the pressure below the inertial mass. This higher pressure delays the closing of the inertial valve, which allows a fast flow of 2.1 fluid from the lower chamber to the upper chamber for a longer period. Two sets of fluid flow ports 48a and 48b are provided for flow from the lower chamber to the housing below the inertial element. At a lower acceleration, the inertial element can move slightly on the piston, opening the lower ports 48a and leaving the upper ports 48b, somewhat larger, closed. There is a deflection of fluid through the lower ports whereby "the damper softens a little.The lip 61 in the inertial element is under the anchor 62 in the piston, the fluid being able to follow a passage through the undercut 64 on the piston, around the lip 61 and beyond the anchor 62 through a release 67 in the inertial mass During this "stage 1" effect, the flow area below the ports 48a of the 1 / a The stage is greater than the area of the ports, as the flow does not cause an appreciable increase in pressure in the box below the lip 61 and the anchor 62. In this way, before minor accelerations of the bar and the piston, the inertial valve opens and stays open only due to its effects. The opening of the valve is effectively insensitive to fluid flow. This operation of the 1 / a. Low acceleration stage is useful for small acceleration events such as those that may be encountered when rolling a tire over an expansion joint between two concrete blocks in a road. A phenomenon known as "highway jump" occurs when a vehicle passes over a uniformly spaced series of such expansion joints. The small repeating events acting on the vehicle are amplified and an annoying cyclic movement is possible. This is particularly problematic in some light trucks that travel without load, with which the rear of the truck can jump too much considering the small magnitude of the accelerations in the expansion joints. The first stage deviation through an inertial valve has been proven to be effective in minimizing the highway jump. An exemplary embodiment may have six first stage orifices 48a, each with an approximate diameter of 1.5 mm. With greater acceleration, the inertial mass moves even more; the upper stage 48b ports also open and the lip and the anchor are close together, allowing a greater volume of fluid to flow once the inertial element has made most of its travel to its fully open position. Near the end of travel of the inertial mass an additional opening force occurs, which only occurs once the acceleration has caused the opening of the valve. The duration of the opening is what is fundamentally controlled during stage two since the fluid pressure in the box tends to keep the valve open once the acceleration has ceased. By varying the longitudinal extensions and the location of the lip and the anchor, the sizes of the ports and the width of the ring between them, the force on the inertial element can be graded in order to provide adequate duration for the opening of the valve for Obtain a good performance of the shock absorber in a specific vehicle type. In one embodiment, 18 holes 48b stage two are used, each with a diameter of 2.2 mm. The flow area through the ring between the lip and the anchor is less than the flow area through all ports 48. It has been found that it is convenient to close the inertial valve quickly in the case of compression before it closes by full. In the case of an increase in the pressure of the upper chamber, fluid flows through the decompression passages 63 through the piston and opens the disc valve 41 to allow direct fluid flow from the upper chamber to the lower chamber; The relay passages are not communicated directly from the upper chamber, as described and illustrated in Figures 1 and 2. These passages, in turn, end in an internal annular undercut portion 64 in the piston below the anchor. This region and the lower end of the inertial mass form a box 66 between the ports 48 and the descending annular restricted flow passage. Although less pronounced in the embodiment illustrated in Figures 1 and 2, an analogous box is provided below the inertial mass. It has been discovered that the fluid in this box tends to slow the closure of the inertial valve. This fluid can not quickly return to the lower chamber as a result of a check valve 51 in a return passage through the ports and must run through the restricted annular space between the lip and the anchor. The fluid box can inhibit the return of the inertial mass to the closed position. With the decompression passages 63 between the lower chamber and the box, the fluid can be quickly extracted from it. A check valve 51 is provided in series with the ports that allows upflow and restricts descending. The check valve comprises a disk valve 76 displaced in a downward direction by means of a helical spring 77. A certain number of holes allow some flow through the disk. The speed of the spring, its constant and the perforated areas can be adjusted in order to obtain the necessary rebound of the wheel for the damping of the movement of the same for a particular model of automobile or vehicle. It has been shown that between and 8 holes, each with an approximate diameter of 1.5 mm, are adequate. Likewise, the greater hydraulic pressure in the upper chamber with respect to the box below the inertial mass when it is in the upper position, produces a great closing force against it, moving it towards its closed position. This force is relatively important while the lower edge of the inertial mass is adjacent to the anchor and the annular space is small. The force decreases as the inertial mass moves in a downward direction and fluid flows from the upper chamber to the decompression passages 63 through an annular unloader 67 above the lower lip 61 on the inertial mass. The annular release allows a greater volume of fluid to flow than when the restricted fluid passage is small. The deviation of the fluid around the lip, as well as the constant higher pressure in the upper chamber, move the inertial valve to its closed position. In this way, the lip on the inertial valve opposite the anchor on the piston fulfills two functions. When the flow of the fluid moves upwardly through the piston during the extension of the wheel, the hydraulic pressure on the underside of the inertial mass increases the opening speed once the acceleration 8 He has started it. On the other hand, when the flow of the fluid is descending, the pressure that is higher on the inertial valve than on the adjacent decompression passages 63 accelerates the closing of the same. It has been found that performance is significantly improved by closing the inertial valve in response to reverse fluid flow. The forces tending to move the valve towards the closing position can be altered by modifying the relative dimensions of the parts in order to change the dimensions of the ring between the lip and the anchor, and of the fluid flow passages. Part of the fluid passes from the box below the inertial mass to the lower chamber through the decompression passages 63, while another portion thereof passes directly from the upper chamber to the lower chamber through the passages 74 and the Lower disc valve 41. This is an additional way to adjust the closing speed of the valve. It has been found that this system for rapidly closing the inertial valve significantly improves the performance of the shock absorber. The valve operates so fast that it can be heard when the inertial mass hits the adjacent parts at the end of its displacement. This noise is minimized by placing a rubber stop that makes contact with the ends of the inertial mass. Even a thin filler can reduce the noise considerably. A ring 0 81 is placed in a channel adjacent to the bottom of the inertial mass as a stop. A rubber ring of square cross section 82 is placed adjacent to the upper end of the race of the inertial mass. It has been found that with a ring at 0 at the bottom, a gasket forms against the bottom of the inertial mass when the inertial valve closes. This gasket can inhibit the rapid actuation of the valve. To minimize this effect, radial channels 83 are formed in the lower part of the inertial mass to alter the surface, otherwise flat and prevent sealing of the O-ring. Figure 4 illustrates the upper end of a double tubular damper. This embodiment illustrates the sensitivity to fluid flow using the principle of a restricted flow downward passage smaller than a flow port in order to keep an inertial valve open for a longer time. The damper has an outer tube 210 sealed at its upper end through an upper end cap 213. An inner tube 214 is also sealed to the upper end cap. Thus, an annular fluid reservoir 216 is defined between the inner and outer tubes. A movable piston 217 is sealed in an inner tube, dividing its interior into an upper chamber 218 and a lower chamber 219. The piston is connected to a shaft 221 which extends through the upper end cap and terminates in an accessory 222 used to bolt the axle to a vehicle chassis 225. A valve responsive to acceleration, recovery or extension is provided at the upper end of the inner tube to allow fluid flow from the upper chamber 218 to the annular reservoir 216 at the case of rapid acceleration of the wheel in downward direction. An axially movable upper sleeve 241 surrounds the inner tube near its upper end. A significant portion of the weight of the upper sleeve is supported by a helical spring of low spring speed 242. The sleeve serves as an inertial mass to control the rebound of the valve. The spring is light enough not to support the total weight of the inertial mass, but simply displaces part of that weight so that it moves more quickly. When the sleeve is in its lower position, ie, in the absence of descending acceleration of the wheel, its lower part rests on a retainer anchor 243 on an inner sleeve 244 as illustrated in the left part of Figure 4 As described when the vehicle wheel encounters a bump in the ground or passes over a spine, bounces or accelerates in a downward direction. Sufficient rapid acceleration leaves the inertial mass 241 in position as the inner tube of the shock accelerates in a downward direction. This opens the valve sensitive to acceleration. When the inner sleeve 241 is moved towards its upper or opening position as illustrated in the right sector of Figure 4, the upper end thereof releases the radial ports 246 through the wall of the inner tube. When the inertial mass is in its lower position against the stop 243, the end of the sleeve covers the ports and prevents fluid flow from the upper chamber to the annular reservoir. The inner sleeve 244 has a conical outer surface that tapers from the relatively small diameter at the upper end to a relatively greater diameter near the lower stop anchor 243. The inner surface of the external inertial mass 241 is essentially cylindrical. The relative dimensions of these parts and the taper angle provide an annular restricted flow passage 247 between the inner and outer sleeve so that substantially in all the race of the inertial mass, the flow area through the flow passage restricted is smaller than that corresponding to the radial ports in the inner tube. Thus when the valve is substantially completely open with the external inertial mass in its upper end position as illustrated on the right sector of Figure 4, a maximum flow area is configured through the ports and the flow passage restricted descending. Since the flow area through the restricted flow passage is smaller than in the ports, the pressure in the space between the displaceable outer sleeve and the fixed internal sleeve is greater than the pressure in the annular reservoir. This tends to displace the inertial material to the opening position. Moreover, in this configuration, when the valve is, for example one third open and two thirds closed, the remaining flow area through the radial ports is still greater than in the annular restricted flow passage between the sleeves as a consequence of the tapering It will also be noted that once the inertial valve in this embodiment is partially open as a result of acceleration, the flow through the partially open ports 246 and in the descending restricted flow passage can induce a greater pressure in the space between the inertial mass and the sleeve and also accelerate the opening of the ports. In the illustrated embodiment, the taper extends over the entire extension of the inner sleeve so that substantially in all of the positions of the outer sleeve the restricted flow passage has a smaller flow area than the ports. If desired, the taper can only extend from the inner sleeve and closer to the lower end of larger diameter, the sleeve becoming cylindrical. In this embodiment, as the valve approaches its closed position, the restricted flow passage stops shrinking, thereby minimizing or eliminating the pressure differential between the space between the sleeves and the surrounding annular reservoir. In this embodiment, the increased pressure tends to keep the valve open when it is fully open and allows it to be closed more easily when the outer sleeve has moved almost completely to the closed position. Small radial grooves (not illustrated) can be provided on stop 243 so that there is a small opening adjacent to the restricted flow passage when the valve is completely closed and the inertial mass is against the stop. Although the internal taper is illustrated in this on a separate sleeve, it is clear that part • The structure that configures the annular restricted flow passage can integrate the internal tube. It is also evident "the possibility of providing the passage of restricted flow of variable area by means of an internal taper within the inertial mass that moves adjacent to an anchor on the external part of the inner tube.

A flow sensitive arrangement to activate the opening of the inertial valve also collaborates to avoid "vibrations" when it is partially open. Although the present invention has been described in detail with reference to certain preferred embodiments thereof, it is clear that numerous modifications, variants and aesthetic changes can be made to the shock absorbers sensitive to acceleration and flow. Some of the check valves may be omitted or replaced by flow restriction passages in some embodiments. The shape of these passages and ducts can be varied or bevelled so that changes between stiffness and softness of the shock absorber can be made at a controlled speed. On the other hand, the invention has been described with respect to an inertial valve that opens before the rebound of the shock absorber. It is evident that the same principles can be employed in an inertial valve that opens during compression of the shock absorber. Thus, the upper, lower and similar expressions are used herein for convenience, while other addresses may be equivalent. Also, although the annular space between the edge of the inertial valve and the surrounding anchor forms a restricted hydraulic flow passage for opening and closing it, independent hydraulic holes could be used.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it refers.

Having described the invention as above, property is claimed as contained in the following

Claims (39)

1. - An acceleration sensitive shock absorber linked at one end to the chassis of a vehicle and on the other to a wheel thereof, characterized in that it comprises: a tubular housing that is connected to a part of the vehicle; a piston assembly in the housing comprising a piston that divides it into an upper chamber and a lower chamber and a piston rod that is attached to another part of the vehicle, one of said parts being the chassis of the vehicle and the other a wheel thereof; means for passing the fluid of the buffer between the upper chamber and the lower chamber with a restricted flow velocity during the compression of said damper; means for passing the fluid of the buffer between the upper chamber and the lower chamber with a restricted flow rate during the extension of said buffer; a port for supplying the flow of fluid between the upper chamber and the lower chamber; a movable inertial mass in the buffer to open the port during the downward acceleration of the vehicle wheel to increase the flow of fluid between the upper chamber and the lower chamber; and a means for applying a fluid pressure to the inertial mass in response to the flow of fluid between the chambers, the means which applies a sufficient pressure to the inertial mass to maintain the inertial mass in an open position of the port in the absence of acceleration. .

2. - An acceleration sensitive damper according to claim 1, characterized in that the means for applying fluid pressure comprises a restricted flow passage below the port, which has a flow area lower than that of the port during at least part of the race of the inertial mass from the port closing position to the port opening position.

3. - An acceleration-responsive damper according to Claim 2, characterized in that it comprises a fluid box between the first port and the restricted flow passage and a second port in fluid communication with the box for passing the fluid between the box and the lower chamber.

4. - A shock absorber sensitive to acceleration according to claim 1, characterized in that it also comprises means for applying hydraulic pressure against the inertial mass in order to move it towards a port closing position.

5. - A shock absorber sensitive to acceleration, characterized in that it comprises: a tube containing shock absorber fluid that is connected to a part of a vehicle; a piston in the tube that divides its interior into an upper chamber and a lower chamber, which connects with another part of a vehicle; and an inertial valve for modifying the stiffness of the shock absorber when it is subjected to acceleration, the rigidity being greater before the acceleration of the body and less before the acceleration of the wheel, comprising: a first fluid port adjacent to a chamber; and a restricted flow passage below the port, which has a smaller flow area than the port for the purpose of creating a fluid pressure against an end or end of the inertial valve means, in response to the flow of fluid through said valve the fluid pressure large enough to keep the valve open until the acceleration decreases.

6. - An acceleration responsive damper according to Claim 5, characterized in that it comprises a second fluid flow port that passes the fluid in the opposite direction through the first port, and a medium that responds to the flow of fluid through the second. port in order to close the inertial valve.

7. An acceleration responsive damper according to Claim 5, characterized in that it further comprises a means for applying hydraulic pressure to the inertial valve means, in response to the flow of the fluid in the Opposite direction for closing the inertial valve.

8. - A shock absorber responsive to acceleration according to claim 5, characterized in that it comprises an inner tube and an external tube fixed thereto with an annular fluid reservoir therebetween, the piston being in the inner tube, while the port passes through the wall of said inner tube, the inertial valve comprises an inertial mass mounted in the annular reservoir to open or close the port, and the restricted flow passage comprises an annular space between the inertial mass and a portion of the inner tube.

9. - A cushion responsive to acceleration, characterized in that it comprises: an external tube; means for connecting the outer tube to a portion of a vehicle; an inner tube fixed inside the outer tube defining between them an annular reservoir for shock fluid; a piston sealed inside the inner tube and connected with an axis that extends towards the exterior of the shock absorber, this shaft comprising a means for its connection with another part of the vehicle, dividing the piston inside the tube in an upper and lower chamber? means for passing the fluid between the upper and lower chambers and the reservoir during compression or extension of the shock absorber; a port through the side wall of the inner tube adjacent to one of the chambers; A displaceable sleeve in the tank that surrounds the portion of the inner tube that contains the port, in order to open it before the acceleration of the tubes in the longitudinal direction and to increase the flow of fluid from one of the chambers to the reservoir in case of a longitudinal acceleration of the shock absorber tubes * and a means for moving the sleeve to the port opening position in response to fluid flow between the chamber and the reservoir, comprising a restricted fluid passage below the port, which has a flow area lower than that of the port during at least part of the race of the sleeve from one of port closing position to an opening position? of port to the effects of applying a differential hydraulic pressure.

10. - An acceleration sensitive damper according to claim 9, characterized in that the restricted flow passage comprises an annular space between the sleeve and a part of the inner tube.

11. - An acceleration responsive damper according to claim 9, characterized in that the port comprises: a top port through the side wall of the inner tube near its top, and wherein the displaceable sleeve encircles an upper portion of the tube internal for the purposes of opening the upper port through the side wall of the inner tube or during the downward acceleration of the shock absorber.

12. - An acceleration sensitive damper connected at one end to the chassis of a vehicle and on the other to a wheel thereof, characterized in that it comprises: a tubular housing that is connected to a part of the vehicle; a piston assembly in the housing comprising a piston that divides it into an upper chamber and a lower chamber, and a piston rod that is attached to another part of the vehicle, one of said parts being the chassis of the vehicle and the other a wheel of it; means for passing the buffer fluid between the upper chamber and the lower chamber with a restricted flow velocity during the compression of said buffer; means for passing the buffer fluid between the upper chamber and the lower chamber with a restricted flow rate during the extension of said buffer; a first fluid port for providing fluid flow between the lower chamber and the upper chamber; a restricted flow passage below the port that establishes the flow between the upper and lower chambers; and a movable inertial mass between a closed position of the port and an open position of the port during acceleration of the wheel, the inertial mass and an adjacent portion of the damper each having non-uniform diameters so that the restricted flow path has a relatively larger fluid flow area when the inertial mass is in a closed port position, a flow area of relatively larger fluid when the inertial mass is in a fully open port position and a relatively smaller fluid flow area, than the port during an average portion of the inertial mass travel between the closed position of the port and the open position of the port.

13. An acceleration responsive damper according to Claim 12, characterized in that it further comprises means for hydraulically deflecting the inertial mass towards a closed position of the port when the fluid flow is in a direction opposite to the flow through the port.

14. An acceleration responsive damper according to Claim 12, characterized in that it further comprises a means for hydraulically moving the inertial mass to a closing position of the port when the fluid flow is in a direction opposite to the flow coming from the port.

15. An acceleration sensitive shock absorber for a vehicle, characterized in that it comprises: a shock absorber cylinder that includes a means for connecting it to the bodywork of a vehicle; a cushion piston in the cylinder that divides it into a lower chamber and an upper chamber, which includes a means for connecting it to a vehicle wheel; means for transferring shock absorber fluid through the piston to the extension of the shock absorber; a fluid flow port through the piston for transferring liquid from the lower chamber to the upper chamber; an inertial mass in the piston that comprises a portion adjacent to the port to close it when the vehicle wheel does not accelerate at a = > extension direction, and to open it when the vehicle wheel is accelerated in the extension direction; and A means for applying hydraulic pressure to the inertial mass in response to fluid flow through the port in order to maintain it in the open position when the port is open; a restricted flow path downstream of the port; a cavity between the port and the restricted flow path adjacent an end face of the inertial mass; means for maintaining a higher hydraulic pressure in the cavity than the hydraulic pressure on the opposite end face of the inertial mass when the port is open; and a second port that communicates between the cavity and the lower chamber, to pass the fluid from the cavity to the lower chamber.

16. An acceleration sensitive damper according to claim 15, characterized in that the hydraulic means comprises a restricted flow passage with a variable area below the port, which has a smaller flow area than the port when it is partially open.

17. - An acceleration sensitive damper mounted between the chassis of a vehicle and a wheel thereof, characterized in that it comprises: a hollow cylinder; a piston assembly in the cylinder that divides it into an upper chamber and a lower chamber, linking the cylinder to the chassis of the vehicle and the piston to the wheel thereof; a means for passing fluid between the upper and lower chambers before compression and extension of the damper with a limited flow velocity; a fluid flow port between the lower chamber and the upper chamber; an inertial mass in the piston assembly axially displaceable between (a) a normally closed position to close the port and (b) an open position to open the port and increase the fluid flow from the lower chamber to the upper chamber during the downward or downward acceleration of the wheel; and a restricted flow path having a variable area downstream from the port for fluid flow, the area of the restricted flow path downstream is smaller than the port area when the port is partially opened to apply a hydraulic pressure to the inertial mass to retain the inertial mass in part or at least partially in the port opening position when the pressure in the lower chamber is greater than the pressure in the upper chamber.

18. - A cushion sensitive to acceleration according to claim 17 / characterized in that it also comprises a means of response to the pressure in order to move the inertial mass towards the port closing position when the fluid pressure is greater in the chamber higher than in the lower chamber.

19. - A shock absorber sensitive to acceleration, characterized in that it comprises: a tubular housing that is connected to the chassis of the vehicle; a piston assembly in the housing comprising a piston that divides it into an upper chamber and a lower chamber, and a piston rod for connection to a vehicle wheel; a compression valve for passing shock absorber fluid through the piston with a limited flow velocity during compression of the shock absorber. a rebound valve for passing a fluid through the piston with a limited flow rate during the extension of the shock absorber; a port of the 1 / a. relatively more dream stage and a port of the 2 / a. relatively larger stage to provide an alternative fluid flow path during extension of the buffer; a movable inertial mass mounted on the piston assembly to open the port of the 1 / a. stage during a minor acceleration of the piston and open the port of the 2 / a. stage during a large acceleration of the piston.

20. - An acceleration-sensitive damper according to claim 19, characterized by-b because ix.ip.arie a cavity that communicates with the ports and attached to the inertial mass and a limited flow down the cavity, the flow area of the port of 1 / a. Etao is smaller than the flow area of the flow restriction and the flow area of the port of the second stage is larger than the flow area of the flow restriction.

21. - An acceleration responsive damper according to Claim 20, characterized in that there is a fluid restriction below the ports having a flow area that changes as a function of changes in the position of the inertial mass.

22. - A shock absorber sensitive to acceleration, characterized in that it comprises: a tubular housing that is connected to the chassis of the vehicle; a piston assembly in the housing comprising a piston that divides it into an upper chamber and a lower chamber, and a piston rod for connection to a vehicle wheel; a compression valve for passing buffer fluid through the piston with a limited flow rate during extension of the shock absorber; a movable inertial mass mounted on the assembly to move between a closed position of the port and a position to open the port during the acceleration of the piston; and a first platform port relatively close to the position of the closed port of the inertial mass and Another second platform port relatively far from the position of the closed port to provide an alternative fluid flow path during the extension of the buffer.

23. - An acceleration responsive damper according to Claim 22, characterized in that the first platform port has a relatively smaller flow area than the second platform port.

24 - an acceleration sensitive damper according to claim 22, characterized in that it comprises a cavity communicating with the ports and attached to the inertial mass and a flow restriction below the cavity, the flow area of the first platform port is lower that the flow area of the flow restriction and the flow area of the second platform port is larger than the flow area of the flow restriction.

25. - An acceleration responsive damper according to claim 22, characterized in that it senses a flow restriction below the ports having a flow area that changes as a function of changes in the position of the inertial mass.

26. - An acceleration sensitive damper comprising: a tube containing the fluid of the shock absorber for connection to a part of the vehicle; a piston in the tube that divides the interior of the tube in an upper chamber and in a lower chamber, for connection to another part of the vehicle; an inertial valve With openings to improve the flow between the chambers to reduce the stiffness of the shock absorber when it is subjected to acceleration in a first direction; and a means for applying a hydraulic force to the inertial valve for tilting the inertial valve to the closed position when the damper moves in the opposite direction.

27. - An acceleration sensitive damper according to claim 26, characterized in that the means for applying a hydraulic force applies a differential pressure through at least one position of the inertial valve.

28. - An acceleration sensitive damper according to claim 26, characterized in that the means for applying a hydraulic force applies a force of momentum of the fluid against at least a portion of the inertial valve.

29. - An acceleration sensitive damper characterized in that it comprises: a tube containing fluid of the shock absorber for connection to the chassis of the vehicle; a piston assembly in the tube that divides the interior of the tube in an upper chamber and in a lower chamber, and that includes a piston rod for connection to a vehicle wheel; an inertial valve in the piston assembly that opens to improve the flow from the upper chamber to the lower chamber during the downward acceleration of the vehicle wheel. a cavity under the inertial valve for hydraulically tilting the inertial valve to hydraulically divert the open inertial valve to an open position of the valve in response to flow through the inertial valve; and a passageway from the cavity to the lower chamber for fluid flow from the upper chamber to the lower chamber.

30. - An acceleration sensitive damper connected to one end of the vehicle chassis and to the other end of the vehicle wheel, characterized in that it comprises: a tubular housing that is connected to a part of the vehicle; a piston assembly in the housing comprising a piston that divides the housing into an upper chamber and a lower chamber, and a piston rod for connection to another part of the vehicle; one of said parts is the chassis of the vehicle and the other part is a wheel of the vehicle; a means for passing the fluid of the absorber between the upper chamber and lower chamber with a limited flow interval during the extension of the absorber; a port for providing an additional flow between the upper chamber and the lower chamber; a movable inertial mass in the buffer to open the port on the acceleration of the vehicle wheel to increase the fluid flow between the upper chamber and the lower chamber; a means for applying fluid pressure to the inertial mass for tilting the inertial mass towards an open port position in response to fluid flow through the port; and a means for applying a hydraulic force to the inertial mass for inclining the inertial mass towards the closed position of the port when the flow of fluid between the chambers reverses the direction.

31. - An acceleration sensitive damper according to claim 30, characterized in that the inertial mass is mounted on the piston assembly and it is connected to the wheel of the vehicle and also comprises: a edge on the piston; a peak in the inertial mass, the peak and the shore cooperating to define an upper end of the cavity inside the piston and under the inertial mass communicating with the port when the inertial mass is in an open port position; and a passageway from the cavity to the lower chamber.

32. - An acceleration sensitive damper comprising: a tube containing the fluid of the shock absorber for connection to a part of the vehicle; a piston in the tube that divides the interior of the tube in an upper chamber and in a lower chamber, for connection to another part of the vehicle; and an inertial valve means for changes in stiffness of the shock absorber when a portion of the shock absorber is subjected to acceleration, the stiffness is greater during a low acceleration and smaller during a high acceleration comprising: a fluid flow port, a inertial mass to close the port in the absence of acceleration and to open the port in the presence of acceleration, a limited flow path between the port and the first of the chambers below the port, a cavity between the port and the path of the flow limited to maintain a hydraulic pressure against the inertial mass during flow through the port, and and an outlet passage between the cavity and one of the second chamber for outflow in the presence of the flow from the first chamber to the second camera .

33. - An acceleration sensitive damper according to claim 32, characterized in that the inertial mass is mounted on the piston assembly, and it is connected to the wheel of the vehicle, and that it is characterized by means of adata: piston; a peak in the inertial mass, the peak and the shore cooperating to define an upper end of a cavity with the piston and under the inertial mass communicating with the port when the inertial mass is in an open port position; and a passage from the cavity to the lower chamber.

34. - An acceleration sensitive damper according to claim 32, characterized in that the limited flow path is thus ordered to apply a hydraulic pressure in the inertial mass in response to the flow of fluid through the outlet passage.

35. - An acceleration sensitive damper according to claim 32, characterized in that the limited flow path is thus ordered to apply a hydraulic pressure in the inertial mass in response to the flow of fluid through the outlet passage.

36. - A shock absorber responsive to acceleration for a vehicle, characterized in that it comprises: a cylinder of the shock absorber including means for connecting the cylinder to the body of the vehicle; a piston of the shock absorber in the cylinder that divides the cylinder into a lower chamber and an upper chamber, and that includes means for connecting the piston to the vehicle wheel; means for passing the fluid of the shock absorber through the piston during extension of the shock absorber; a port of fluid flow through the piston to pass fluid from the lower chamber to the upper chamber; an inertial mass in the piston that includes a portion adjacent to the port to close the port when the vehicle wheel does not accelerate in an extension direction, and open the port during acceleration of the vehicle wheel in the extension direction; a flow path limited below the port; a cavity between the port and the limited flow path adjacent an end face of the inertial mass; a means to maintain a greater hydraulic pressure in the cavity, than the hydraulic pressure at the opposite end face of the inertial mass when the port is open, for a sufficient application of the hydraulic pressure in the inertial mass in response to the fluid flow to through the port to keep the inertial mass in the open position when the port is open; and a vent passage with a check valve communicating between the outlet and the lower chamber for the passage of fluid from the cavity and the lower chamber.

37. - An acceleration sensitive damper that is connected between the chassis of a vehicle and a vehicle wheel, characterized in that it comprises: a hollow cylinder; a piston assembly in the cylinder that divides the cylinder into an upper chamber and a lower chamber, the cylinder is connected to the chassis of the vehicle, and the piston assembly is connected to the vehicle wheel; a means for passing the fluid between the upper chamber and the lower chamber during a compression and extension of the absorber with a limited flow interval; a fluid flow port between the lower chamber and the upper chamber; an inertial mass in an axially movable piston assembly between (a) a normally closed position to close the port and (b) in an open position to open the port and increase fluid flow from the lower chamber to the upper chamber during the descending acceleration of the wheel; a means for retaining the inertial mass in the open position of the port when the pressure in the lower chamber is greater than the pressure in the upper chamber; and a means of responding to hydraulic pressure to move the inertial mass toward the closed position of the port when the pressure in the upper chamber is greater than the pressure in the lower chamber.

38. - A shock absorber responsive to acceleration for a vehicle, characterized in that it comprises: a cylinder of the shock absorber including means for connecting the cylinder to the body of the vehicle; a piston assembly in the cylinder that divides the cylinder into a lower chamber and an upper chamber, and which includes means for connecting a piston assembly to the vehicle wheel; means for passing the fluid of the shock absorber through a piston assembly during the extension of the shock absorber; a fluid flow port through a piston assembly to pass fluid from the lower chamber to the upper chamber; an inertial mass in a piston assembly that includes a portion attached to the first port to close the first port when the pressure in the upper chamber exceeds that of the lower chamber, and the first port is opened during the acceleration of the vehicle wheel in the downward direction; one edge in the piston assembly; a peak in the inertial mass attached to the shore when the inertial mass is a position where the port is at least partially open; an annular notch below the edge; and an annular recess above the peak.

39. An acceleration responsive damper according to claim 381 characterized in that it further comprises a passageway between the notch and the lower chamber.