Patent GB-582467-A (GB)
Title: Fluid shock absorbers
IPC: F16F9/44
Filed: 1944-05-18
Abstract: 582,467. Shock-absorbers. TRIGGS, W. W. (Gabriel Co.). May 18, 1944, No. 9584. [Class 108 (iii)] In a direct-acting shock-absorber in which relative rotation of the piston and cylinder from a predetermined position is adapted, by means of interengaging elements on the two parts, to. adjust valve means which control the flow of fluid, one of the elements is movable independently of the part which carries it and spring means acting on this element urge it constantly in one direction. The double-acting shockabsorber shown comprises concentric cylinders 15, 16 arranged to form an annular reservoir 17 which communicates at its lower end with the compression chamber 20 through an orifice 23 in a plug 22 closing the lower end of cylinder 15. The upper ends of the cylinders are closed by plugs 25, 27, plug 27 carrying a spring-pressed packing 29 through which the piston-rod 12 is slidable. Entry of dust &c. between the outer cylinder 16 and a tubular guard 14 carried by the piston-rod is prevented by packing 32 held between shoulders 33 on the cylinder. The piston 18 comprises three main parts 18a, 18b, 18c which clamp between them washers 34, 35, the lower washer 35 being pressed frictionally against the cylinder 15 by a spring ring 37. Passages for flow of fluid through the piston comprise axial and radial passages 38, 39 in the piston-rod, an annular space 40 in the part 18a, and openings 41 in the part 18c, and, in addition, openings 42 in the part 18b, and one or more openings 43 in the part 18a. The part 18b has a sleeve portion containing a chamber 45, with which the piston-rod passage 38 connects, formed by a plug 46 screwing into the sleeve 44, the plug having slots 47 through which project arms 52 on an adjusting member 51 held against the plug 46 by a spring 55. A disc valve 48 mounted on a guide pin 50 on the plug is normally pressed against the end of the passage 38 by a second spring 49. Operation. On compression, fluid flows upwardly through the slots 47, into chamber 45, through the openings 42, an annular space 56, radial passages 57,-axial grooves 58, and around the washer 34 into the chamber 19. Fluid is also forced from the openings 42 through the passage or passages 43, annular space 40 and openings 41 into the chamber 19. Resistance is also provided by the frictional drag of washer 35 and the restricted flow of fluid through the orifice 23 into the reservoir 17. On rebound, fluid flows downwardly from chamber 19 through the openings 41, annular space 40, openings 43, 42, chamber 45 and slots 47 into the chamber 20, the washer 34 being forced against the cylinder wall by the fluid pressure. Some resistance is again provided by the frictional drag of the washer 35. When the fluid pressure rises sufficiently, the valve 48 is unseated and additional flow occurs through the passage 38 in the piston-rod and the piston chamber 45 to the chamber 20. Adjustment. Resistance to rebound may be varied by varying the compression of the valve spring 49 and this is effected by compressing the shock-absorber until the arms 52 engage recesses 53 in the closure plug 22 of cylinder 15, and then rotating the piston and cylinder relatively so that the plug 46 is screwed into or out of the sleeve portion 44 of the piston part 18b. Should the arms 52 strike the plug 22 during operation of the shock-absorber, the adjusting member 51 is simply pushed back into the chamber 45 against the action of the spring 55.