GB747043A - A device for measuring or measuring and sorting hollow tubes - Google Patents

Abstract

747,043. Linear dimension gauges. BUNDER-GLAS GES. Feb. 9, 1954 [Feb. 13, 1953], No. 3733/54. Class 106 (2). [Also in Group XXIII] In an apparatus which indicates the average internal diameter of a tube or like annular body, and which can be adapted to indicate the average wall thickness of such an object, several feelers whose axis lie on a cylindrical surface are each connected to the corners of a polygonal frame, symmetrically placed around them, and springs, acting radially outwards at these corners, tension the frame and bring the feelers into contact with the inside wall of the object, so that any relative radial movement of the feelers causes a variation in the peripheral length of the polygonal frame, which variation is a measure of the average internal diameter of the object. The six feelers 12-17, Fig. 2, only two of which, 14, 17, are shown in Fig. 1, are fixed at their ends to a ring 39 and can pivot about a point adjacent to the ring by virtue of a thin portion 37. Each feeler 17 is linked by a wire 18 to a plate 33, Fig. 3, situated at a corner of a hexagonal frame formed of wires 25-29 and belts 30, 31 wound in opposite directions on a shaft 32, the frame being supported by springs 35 which permit it to rotate slightly about its axis. Springs 48, 49 and belts 46, 47 apply a couple to the shaft 32 tending to wind the belts 30, 31 on to the shaft, so that because of the way in which the polygonal frame is supported if a feeler is displaced radially inwards an additional portion of the belts 30, 31 is wound on to the shaft 32 and the shaft 32 rotates and moves a rod 50 to work an indicator or control a sorting device. In order to insert the feelers into the object 11 being gauged, the supporting ring 39 is moved to the right (to the position shown dotted in Fig. 1), carrying the feelers with it, to cause rollers 43 pivoted to the feelers to bear against a fixed abutment 44 and force the feelers radially inwards. In a second embodiment, for determining the average wall thickness of a tube, Fig. 4, a second set of feelers 80, pivotally fixed at 81 to the first set 79, has the polygonal frame attached to its inner end 85 immediately above the pivot 37 on the first set. The peripheral length of the frame therefore varies only when the wall thickness of the work being gauged varies since if the internal diameter of the work varies while the wall thickness remains constant, the feelers will maintain their parallel relationship and pivot, the first set about 37 and the second set about their end 85, and the pivot 85 will remain at the same point in space. A device for holding the work being gauged is also described (see Group XXIII).