Patent GB-411160-A (GB)
Title: Improvements in or relating to swivel or pivot joints
IPC: B23Q1/54
Filed: 1932-12-03
Abstract: 411,160. Universal joints. BROWN, M., 8, Chorley Drive, Fulwood, Sheffield. Dec. 3, 1932, No. 34258. [Class 65 (ii).] A tool or work holder for a machine tool is formed in two parts connected by a pivot having its axis inclined at fixed angles to the axes of both parts of the holder and intersecting these axes at the same point or at different points, so that the two parts may be brought into any angular relation to one another, within the limits imposed by the angles between their axes and the pivot axis, by rotation about the pivot axis. The clamping device for the tool or work may be mounted on one part of the holder so as to be rotatable about the axis of that part, and the other part of the holder may be rotatable about its own axis on the machine carriage or bed. The pivot may have a material axis formed by a spindle or shaft, which may be used to transmit power to one of the holder parts or to any apparatus carried thereby ; alternatively, or in addition, the parts may have annular or overlapping cylindrical bearing surfaces coaxial with the pivot axis. The spindle and bearing surfaces may be provided with ball or roller bearings. One of the parts may be provided with gear teeth for engagement with a toothed wheel or member rotatable on the other part, whereby the angular relation between the two parts may be constantly varied or an object mounted on the toothed member may be automatically rotated as the two parts of the holder are moved relatively to one another about the pivot axis. Any desired means may be provided for locking the parts together in any position. In a modification, giving a greater range of relative positions, the two holder parts are both connected to an intermediate member by joints of the type described, and the intermediate member may itself be formed with one or more such joints ; in this case the two holder parts may be prevented from rotation on their own axes, their relative position being varied by rotation of the intermediate member only. The Figure shows a work holdercomprising a cylindrical pedestal part 1, with vertical axis, for fixing on the machine bed, a table-carrying part 2, also cylindrical and having its axis horizontal in the position shown, and a table 3, to which the work is clamped, mounted on the part 2 to rotate about the axis of the latter. The parts 1, 2 have bearing faces 9, inclined at 45‹ to both their axes, formed on circular flanges on the parts and held together by a clamping ring 11 and bolts ; the parts can thus rotate relatively about an axis A, inclined at 45‹ to the axes of the parts, to bring the part 2 into any position from the vertical to the horizontal. The table 3 has an annular bearing surface for engagement with a flanged face of the part 2, a clamping ring also being provided for this joint. The table also has a cylindrical extension having fixed to it a bevel wheel 6 engaging with a similar wheel 14 mounted on a spindle 13 carried in a bearing in the pedestal 1 and having its axis coincident with the pivot axis A. The spindle 13 is driven by a worm gear from a shaft 16. If the table 3 is locked to the part 2, rotation of the spindle 13 will cause the part 2 to rotate on the part 1 about the axis A, varying the inclination of the table. When the table has reached the required inclination, parts 1, 2 may be locked together and table 3 released, whereupon further rotation of the spindle 13 causes rotation of the table on its own axis. Scales and pointers or verniers are preferably provided at both bearings. An independent drive for the part 2 may be provided by a pinion on a shaft carried by part 1 engaging with teeth on the periphery of the bearing flange of part 2.