Patent GB-593912-A (GB)
Title: Improvements in vibration-damping supporting arrangements for stationary machinery
IPC: F16F15/067
Filed: 1945-02-06
Abstract: 593,912. Machinery supports. GENERAL SPRING CORPORATION. Feb. 6, 1945, No. 2959. Convention date, Jan. 28, 1944. [Class 80(iv)] [Also in Group XXXII] In a supporting arrangement for damping vibrations between a stationary machine and its foundation in which the machine mounting is resiliently supported from the foundation by a main spring or springs which are deflected under the static load imposed by the machine when at rest through only a part of their available amplitude, one or more auxiliary springs are arranged in relation to the main spring or springs between parts fixed respectively to the mounting and the foundation, and are of free length greater than the minimum spacing and less than the maximum spacing between the parts during vibratory movements of the machine when operating. The load deflection characteristic of the spring system is thereby sharply changed within the normal range of vibratory movement of the machine. In the construction shown in Fig. 2, an electric motor 2 mounted on a base plate 6 is supported by main springs 8 above a box shaped foundation structure 10 of concrete, wood or metal etc., the sides 12 of which guide the baseplate 6. Auxiliary springs 16, 22, 24, operate in conjunction with the main springs, the length of the springs 16, 24 being such that in the mean operating position of the motor 2 under load they are each only just in engagement with both their relative abutments. The spring 22 is also only just in contact with both its abutments in the mean operating position and due to its central position is placed under load by deflection of the motor in either direction from the mean position. A rebound spring 15 is provided, and clattering of the auxiliary springs 16, 22, 24 is prevented by rubber or other cushions 25 moulded etc. to the upper ends of the springs. Inserts 26 of sound deadening material may be secured to the sides 12 of the foundation 10 by clamping plates 28. In another construction, Fig. 4, an electric-motor 2a is suspended from an overhead foundation 68 by a plurality of vibration damping supports each comprising a cylinder 40, connected by a rod 54 with a mounting 6a of the motor and having a piston 36 connected with the foundation 68 by a ball and socket connection 72, a main spring 8a being located between the piston 36 and a cylinder head 38. An auxiliary spring 22a within the main spring 8a is located between an adjustable abutment 50 in the head 38 and a socket portion 48 of the piston 36, the adjustment of the abutment 50 and a turnbuckle 56 in the rod 54 being such that the spring 22a is just on the point of receiving load in the mean operating position. Similar vibration damping supports 40 are connected between the motor mounting 6a and a lateral foundation 80. In a further construction a hydraulic press is suspended from either side of its base by vibration damping supports of similar construction to those shown in Fig. 4. The supports of either construction may employ tension springs, the auxiliary spring 27c, Fig. 7, having sections of variable stiffness, related to different mean operating positions corresponding to respective stages of operation in the functioning of a machine. Compression auxiliary springs may provide variable stiffness by having coils of variable pitch or by utilising a plurality of springs in series or parellel. Specification 565,189, [Group XXXII], is referred to.