Patent GB-672593-A (GB)
Title: Improvements relating to shock absorbers for motor vehicles
IPC: F16F7/09
Filed: 1950-09-20
Abstract: 672,593. Friction-surface shock-absorbers. SOC. APPLICAZIONI GOMMA ANTIVIBRANTI S.A.G.A. SOC PER AZIONI. Sept. 20, 1950 [Oct. 7, 1949], No. 23103/50. Class 108(iii) In a frictional type vehicle shock-absorber the operative friction surfaces on the relatively moveable members of the shock absorber are devoid of effective frictional engagement when the members are at rest, and are brought into engagement by means which come into operation automatically as a result of relative movement of the members, the shock absorbing action of the surfaces then following a predetermined law. A rubber annulus 10 secured as shown by flanges 9, 11 or alternatively by vulcanization to a sleeve 8 rigid with a piston rod 6, has a peripheral friction surface 17. An inertia mass 13 has sliding movement on the rod 6 limited by a rubber ring 14 and stop 15. The cylinder below the annulus 10 is filled with liquid 20. In operation, on downward movement of the rod 6, the inertia mass 13 deflects the annulus 10 to bring the friction surface 17 into engagement with a friction surface formed by the inner periphery of the cylinder. This action is enhanced by pressure exerted on the annulus by the liquid 20 which escapes through an orifice 21. In a modification (Fig. 1, not shown), the liquid is replaced by a gaseous medium no orifice 21 being provided. Alternatively the same effect may be obtained, Fig. 4, (not shown), by a coiled, leaf, rubber or other suitable spring acting between a shoulder on the lower end of the cylinder (which is open to atmosphere), and the lower face of the annular member 10. Either spring, air, or liquid, may however be dispensed with Fig. 3, (not shown), the effect of the inertia weight only, being relied upon. The inertia weight may comprise three separate masses differing in size so that they go into action successively. They are separated by resilient washers but the masses are so shaped that after a predetermined degree of deflection of a washer between two adjacent masses, the latter engage with positive contact. A second annulus 10 and associated friction surface 12 may be mounted between the collar 15 and the inertia mass 13 to provide a double acting device. The friction surface 17 may (as shown), be in the form of a covering 12 of material having a high coefficient of friction and this may be of segmental form. Alternatively, fibres of material such as amianthus may be incorporated (throughout, or in a peripheral strata thereof), in the rubber of the annulus to provide the surface of the latter with the desired coefficient. In the construction shown in Fig. 7, the annulus 10 is secured to the cylinder and the frictional surface 17 is provided on its inner periphery and co-operates frictionally with an enlarged section 6<SP>1</SP> of the rod 6. Rebound of the inertia weight is limited by a resilient ring 28 carried by the cylinder. In a modification of this construction Fig 8, (not shown) the annulus 10 is not secured at its periphery to the cylinder but is slidable relative thereto as well as in relation to the piston rod, with frictional damping action in each case. The periphery of the member 10 may be slightly rounded (in the axial direction), in order to produce a seizing action between the surface 17 and the surface of the cylinder when relative movement occurs between them.