Patent GB-738861-A (GB)
Abstract: 738,861. Testing balance of rotary bodies. DUNLOP RUBBER CO., Ltd. March 8,1954 [March 21, 1953], No. 7844/53. Class 106 (2). Apparatus for determining the magnitude and direction of the couple necessary to dynamically balance a circular body (e.g. a car wheel) consisting of a carrier, for holding and rotating the body, rotatably mounted on a balanced swing- ing frame pivotally supported for movement about a horizontal axis, means for indicating the angular deflection of the frame from its balanced position which is that in which the carrier is horizontal, and a balancing beam which rotates with the carrier, having its mid-point on the axis of rotation of the carrier, and being capable of movement about an axis parallel to the plane of the carrier, the apparatus being characterized in that the angular position of the beam about the axis of rotation of the carrier relative to the carrier can be varied while the carrier, and the beam, are in motion. The swinging frame 1, Fig. 1, pivotally mounted on two stanchions 2 on a base 3 supports a wheel carrier 10, an electric driving motor 20 and a member 46 which carries the dumb-bell shaped balancing beam 60, any angular movement of the frame being indicated on a scale 65 by a beam of light and mirrors located in the housing 9 as described in Specification 636,894, and any oscillations of the beam being damped by rods 7 and dash-pots 8. The wheel carrier 10, Fig. 3, having a shaft 11 is driven by a friction ring 16 embedded in a parallel disc-shaped flange 15 which is rimdriven by a pinion 18 from a quick start and stop motor 20. A liner 12, carried in bearings 13 seated in the main frame 1, supports the flange 15 and extends for only a part of the length of the shaft 12, the remaining portion of the shaft being surrounded by a member 22, held in bearings 24 in the frame 1 by a plate 26, to which is fixed the supporting member 46 by screws 45. Slidably mounted on keys 33 projecting from a sleeve 34 fixed to the shaft 12 so that it rotates with the shaft is the spigoted end 32 of a four-start threaded screw 31, the position of the screw in the shaft being controlled by a spring 35 and a Bowden cable 51, the casing of which is fixed on a bearing 49 to the end of the member 46 and the wire of which is fixed on a bearing 42 to a head-piece 40 on the end of the screw 31. Four studs 37 with lock-nuts 39 are positioned in the member 22 to engage one thread each of the screw 31, so that when the shaft 12 rotates so also will the member 22. Also when the screw 31 is moved along the shaft by the Bowden cable the member 22 will rotate relative to the shaft, the amount of rotation depending upon the distance moved by the screw. Two struts 59, Figs. 1, 3, pivoted at 58, carry two cylindrical weights 60 bolted to spigots 61 which slide, being held in position by friction, on the convex surfaces of two shoes 62. In operation a wheel is placed on the carrier 10 and statically balanced by rotating it by hand and by using the scale 65 which indicates any angular movement of frame 1. The balancing beam is set horizontal, the wheel rotated by the motor and the maximum deflection of the frame observed on the scale 65 which is graduated to indicate the magnitude of the disturbing couple. The balancing beam is then positioned, by the aid of a scale on one of the shoes 62 to apply a couple indicated by the scale 65 and the wheel is again rotated. As the wheel rotates the Bowden cable is operated to rotate the beam relative to the wheel until the frame ceases to oscillate as indicated by the scale 65. The wheel is then stopped and the position of the beam relative to the wheel indicates the direction of the disturbing couple. Specification 652,774 also is referred to.