Patent GB-576025-A (GB)
Title: Improvements in or relating to hydraulic shock absorbers
IPC: F16F9/40
Filed: 1943-06-16
Abstract: 576,025. Hydraulic shock-absorbers. NEWTON, E. P. (Monroe Auto Equipment Co.). June 16, 1943, No. 9696. [Class 108 (iii)] Relates to a hydraulic shock-absorber of the piston - and - cylinder type in which the piston-rod 11 is slidable through an end closure 10 in the cylinder A and a casing 9, concentric with the cylinder, is carried bv the closure 10 to form a reserve chamber B in co-operation with the cylinder. According to the invention, a tubular partition E connected to the closure 10 is provided in the reserve chamber, forming annular spaces 40, 42 respectively between the cylinder and casing and having its lower end below the normal level X of liquid in the reserve chamber, the space 40 being in communication with the cylinder to receive liquid and air therefrom and in open communication with the lower portion of the reserve chamber, while the space 42 is open only at its lower end to provide a trap for air, means at the lower end of the space 42 co-operating with the casing 9 to provide a restricted inlet for air to the air trap and, with the partition E, to exclude liquid as far as possible from the air trap. As shown, the closure 10 is provided below a seal 12 with an annular pocket 32 for liquid scraped off the rod 11 by the seal, with an inclined passage 33 for conducting liquid from the pocket to the reserve chamber B, and with an annular groove 34, at the junction of the passage 33 and cylinder A, connected by a restricted air passage 35 to the interior of the cylinder. A slight clearance passage 36 is also provided between the closure 10 and rod 11 leading from the cylinder to the pocket 32. The partition E has a flanged upper end 37 secured to the closure 10 and is arranged closer to the cylinder A than to the casing 9 to provide a relatively large air trap in the space 42 above the lower flanged end 38 of the partition which is slightly spaced at 41 from the casing. Embossed portions 44 hold the partition in proper spaced relation to the casing and cylinder. The piston C has two series of openings 23, 24 controlled respectively by a spring-pressed disc valve 25 and a laminated spring valve 26, and a second valve assembly D is provided at the lower end of the cylinder A comprising a body 13 having a relatively large central opening 14 and a series of concentric openings 15 controlled respectively by a spring- pressed disc valve 16 and a laminated spring valve 17. Operation.-On compression of the shockabsorber liquid flows through the piston passages 23, past the valve 25, and also through the passages 15 in the body 13, past the valve 17, while, on extension, liquid flows through the piston passages 24, past the valve 26, and through the opening 14 in the body 13, past the valve 16. During extension, a certain amount of air passes through the restricted passage 35, groove 34 and passage 33 to the annular space 40 and thence beneath the flared end 38 of the partition into the air trap in the space 42, while some of the liquid escapes through the clearance passage 36 into the pocket 32 and through the passage 33 to the annular space 40 where it joins the other liquid in the reserve chamber B. Hence, on rebound, the air is first cleared out and then escaping liquid flows into the reserve chamber, the flared lower end 38 of the partition E serving as a baffle to prevent liquid discharging into the air space 42. On compression of the shock-absorber, the partition prevents air instead of liquid from being drawn from the space 42 through either the passage 35 or clearance 36 into the cylinder A. Reference has been directed by the Comptroller to Specification 458,311 and U.S. A. Specification 2,048,285.