Patent GB-567367-A (GB)
Title: Improvements in or relating to inertia controlled shock absorbers for motor vehicles
IPC: F16F9/504
Filed: 1943-02-17
Abstract: 567,367. Hydraulic shock-absorbers. MONROE AUTO EQUIPMENT CO. Feb. 17, 1943, No. 2667. Convention date, Oct. 6, 1941. [Class 108 (iii)] A hydraulic shock-absorber for motor vehicles comprises a cylinder 10, Fig. 3, in which operates a piston 15 having passages 36, 37 therethrough for flow of fluid, leaf-spring valves 34, 35 carried by the piston for controlling the flow of fluid in opposite directions through the passages, and means including a slidable valve member 61 controlled by an inertia weight 60 for conducting fluid from one of the passages to the back of the valve 34 or 35 controlling. the passage to resist opening movement of the valve. Screwed in the hollow end of the pistonrod 16, which is connected to an end plate 14 carrying a tubular dust-shield 12 concentric with a reserve chamber 11 enclosing the cylinder 10, is a tubular member 26 provided at its lower end with an enlargement 27, and positioned on the member 26 are guides 28, 29 for annular slides 30, 31. The laminated leafspring valves 34, 35 extend between inwardlyprojecting flanges 32, 33 on the slides and the top and bottom of the piston 15, washers 38, 39 clamping the valves against the piston and also clamping star-shaped leaf-springs 40, 41 against the guides 28, 29. The springs 40, 41 normally press the flanges 32, 33 of the slides 30, 31 into engagement with the valves 34, 35. Recesses in the guides 28, 29 and slides 30, 31 co-operate to provide annular high-pressure fluid chambers 44, 45 in open communication with passages 46, 47 and, through diagonal passages 52, 53, with two sets of transverselyextending passages 48, 49 in the tubular member 26. Spaces 54, 55 around the member 26 are connected by diagonal passages 56, 57 to the piston passages 36, 37. The slidable valve member 61 is constituted by the stem of the inertia weight 60 and contains recesses 62, 63 for establishing communication between the passages 48, 49. A central rod 64 secured at its upper end to the member 26 passes freely through the weight 60 and has a nut 67 at its lower end carrying a cup-shaped cap 68 slidably engaging a tubular shield 69 for the weight which is supported by a spring 70 from the cap. An annular projection 74 on the weight is movable in a space 75 between the shield 69 and the enlargement 27 of the member 26 and, on upward movement of the weight, is adapted to engage a leaf-spring 76 forming a yieldable stop. Another leaf-spring 77 acts as a stop on downward movement of the weight. At the bottom of the cylinder 10 a compression valve assembly 80 is provided comprising a body 81 secured to the cylinder and having a large opening 82 and smaller openings 83, a disc valve 84 controlling the opening 82 and having peripheral openings 85 registering with the openings 83. Spring arms 86 normally hold the valve 84 in closed position and a leafspring valve 87 controls the smaller openings 83. A flange 88 on the body 81 engages indentations 89 in the closed bottom 24 of the reserve chamber 11 providing passages for free flow of fluid between the reserve chamber 11 and valve assembly 80. Operation.-The inertia weight 60 is carried by the body or sprung part of the vehicle and does not move if the body does not move and it is set so that in the neutral position, shown in Fig. 3, the high-pressure passages 48, 49 are closed. On slight upward movement of the road wheels, the piston 15 moves into the cylinder 10 and fluid under pressure flows into the passages 36 causing the valve 34 to flex upwardly, lifting the slide 30 so that fluid flows past the valve 34 against only slight resistance. As the piston-rod 25 enters the cylinder, a like volume of fluid passes out through the openings 83 past the valve 87. On slight downward movement of the road wheels, fluid flows downwardly through the passages 37, flexing the valve 35 downwardly and lowering the slide 31, while, as the piston-rod leaves the cylinder, fluid flows from the reserve chamber 11 past the valve 84. When upward movement of the road wheels compresses the shock-absorber, the weight 60 assumes a slightly lower position in the cylinder 10, as shown in Fig. 10, so that while the uppermost passages 48, 49 remain closed, the recess 63 establishes communication between the lowermost passages 48, 49. This communication, however, is ineffective as fluid is moving upwardly through the piston passages 36, so that the only resistance is still supplied by the valve 34 and by the valve 87. Similarly, when downward movement of the road wheels extends the shock-absorber, the only resistance to flow of fluid is still provided only by the valves 35 and 84. When the vehicle body moves suddenly and rapidly downwards, the weight 60 assumes the fully-raised position shown in Fig. 11, with the recess 62 in the stem 61 establishing communication between the uppermost passages 48, 49, while the recess 63 is above and out of communication with the lowermost passages 48, 49. Hence, fluid flows through the passages 36, diagonal passages 56, space 54, passage 49, recess 62, passage 48 and passage 52 to the pressure chamber 44, thus increasing the resistance of the valve 34 to flow around its periphery. Resistance is also provided by the valve 87 as fluid flows from the cylinder 10 to the reserve chamber. On sudden upward movement of the vehicle body, the weight 60 assumes the fully-lowered position and fluid passes to the pressure chamber 45 to increase the pressure on the valve 35. Resistance is also provided by the valve 84 to flow of fluid from the reserve chamber 11 to the cylinder 10.