GB656547A - Improvements in or relating to anti-vibration mountings - Google Patents

Abstract

656,547. Resilient mountings. DOBBIE McINNES, Ltd. April 23, 1947, No. 10824. [Class 108 (iii) ] An antivibration mounting for an object comprises two longitudinally inextensible and fixedly located pendulums, one 23, Fig. 5, upright, and the other 22 inverted, and link means 24 between deflectable parts of the pendulums and adapted to carry the object to be mounted. The supports for fixedly locating the unmovable ends of the pendulums 22, 23 are omitted from Fig. 5. In the construction shown in Fig. 4. the link means comprises a further pair of pendulums 23a, 22a, upright and inverted respectively, between which a frame 37 for carrying the object to be supported, is connected. A frame 32 is fixed at one corner, to an inverted pendulum 22 formed by the upper end of a flexible member secured at its lower end to brackets 33 on a base 31. The frame 32 is also fixed, at its diagonally opposite corner to the lower end of a pendulum 23 formed by a similar flexible member whose upper end is secured at 34 to elongated brackets on the base. The frame 32, which is thus able to oscillate in its own plane, carries upper and lower arms a, b projecting at right angles to and in opposite directions from its plane, which arms carry respectively the upper and lower ends 36, 35 of flexible members comprising the pendulums 23a, 22a and whose other ends are connected to the frame 37. This latter can thus oscillate through the plane of the frame 32, and has universal movement. The resilient arms, which are made as long aspossible, may comprise a single elastic strip, or two strips in cruciform and pinned together at their mid points, or two strips arranged in V-shape. The resilient arm 23, Fig. 4, may be arranged to touch, the rounded edge of the supported frame when large deflections occur, so as to increase the damping effect, and pivoted arms may be used instead of resilient ones. A weight 38 may be attached to either or both frames to increase 'the period of vibration of the system, but if' the inner frame alone is weighted for this purpose, a balance weight may be needed for the outer frame. The periods of vibrations of the inner and outer frame should be kept as different as possible.