GB645623A - Improvements in hydraulic shock-absorbers - Google Patents

Abstract

645,623. Hydraulic shock absorbers. EZBELENT, G. E. Feb. 17, 1948, No. 4584. [Class 108(iii)] An hydraulic shock absorber comprises a piston 1 sliding in a cylinder 2, a valve 16 permitting flow in one direction past the pistons but preventing return flow, a narrow passage 53 of variable section allowing the liquid to return with a throttling action, and inertia means for automatically controlling the variation in section of the passage 53, the inertia means comprising a weight 24 slidably mounted in a liquid-filled chamber, orifices 45, 48 adapted to allow passage of liquid from one side to the other of the weight and throttling means for varying the section of the orifice. A head 4 rigid with the cylinder 2 defines a secondary space 10, the volume of which equals the volume of piston rod which enters the main cylinder space at maximum compression. The piston has orifices 12, 15 controlled by the valve 16 and through which pass respectively hollow rods 11, 53a. The rod 11 has a variable external diameter, is open at its lower end, and opens at 11a into the space 10. The rod 53 is secured at respective ends to the head 4 and the lower main cylinder head 3, and has orifices 54. 55 which connect the passage 53 within the rod, with the cylinder spaces above and below the piston respectively. The inertia weight 24 is slidably mounted on a stem 46 rigid with the head 3. The orifices 48 are controlled by a spring-loaded valve 49. Operation. In its normal position the weight 24 covers the orifice 55. On relative inward telescopic movement of the piston and cylinder the weight 24 moves rapidly downwards and uncovers the orifice 55, since flow through the orifices 48 opens the valve 49. On the rebound the orifices 48 are closed and flow past the weight 24, is limited to clearances 45, the initial damping being slight until the orifice 55 is covered. During high frequency oscillations the weight remains in its lower position and damping is small.