GB1371775A - Viscoelastic damper - Google Patents

Abstract

1371775 Springs LORD CORP 16 Aug 1971 [26 Oot 1970 13 May 1971] 37761/73 Divided out of 1371774 Heading F2S A damper for resiliently damping relative movement between two relatively movable members comprises a first plate structure having two spaced apart rigidly interconnected outer plates 56, Fig. 4, a second plate structure including at least one inner plate 52 between the plates 56, viscoelastic material 50 in the spaces between the plates 52, 56 and secured thereto, and means 70 interconnecting the outer plates 56 for preloading the material 50 to the extent permitted by spacers 76, the plate structures having respective means 53, 66 for attachment to the said members so that on relative movement thereof the viscoelastic material is deformed predominantly in shear. Alternatively, Fig. 7, the first plate structure includes plates 85, 86 bolted to a central plate 82, while the second plate structure includes plates 83, 84 bolted together. The plates 83, 84 have outwardly facing concave surfaces and the plates 85, 86 complementary convex surfaces for preventing relative transverse movement of the plates. The viscoelastic material is preferably silicone rubber, but other examples are given. The damper is particularly intended for use as a lead-lag damper in a helicopter rotor; a rotor per se is claimed in Specification 1,371,774. (see Division B7). Reference has been directed by the Comptroller to Specification 1,333,246.