Patent GB-909336-A (GB)
Title: Improvements in or relating to tubular guide arrangements
IPC: G03B3/02
Filed: 1960-10-28
Abstract: 909,336. Bearings. LEITZ G.m.b.H., ERNST. Oct. 28, 1960 [Nov. 13, 1959; July 7, 1960], No. 37116/60. Class 12 (1). [Also in Group XX] A tubular guide arrangement comprises an inner tube slidable in an outer tube, each tube having at least two grooves extending parallel to its axis, the grooves being provided on adjacent tube walls and being arranged so that each groove of one tube registers with a corresponding groove of the other tube, a guide rod being provided between each pair of registering grooves and contacting groove walls of said registering grooves, the arrangement being such that the adjacent groove walls contact the interposed guide rods but that the adjacent tube walls do not contact each other, the guide rods allowing slidable movement in the axial direction, but preventing rotational movement, of the tubes relative to each other and being of such a diameter that substantial play between the tubes is avoided. As shown in Fig. 3, tubes 21, 22 are provided with co-operating V-grooves between each pair of which there are guide rods 16 dimensioned to prevent lateral play during relative sliding movement of the two tubes. The rods 16 are selected from a number available so as to take into account manufacturing defects in the grooves or in the groove arrangement. The two tubes may be part of a focusing lens mount and one guide rod may be additionally employed to transmit a setting movement, for example, to the diaphragm. For instance, as shown in Fig. 6, a focusing lens mount is secured by a bayonet catch 103 to a camera 104 so that the spring-loaded plunger 107 on the lens mount is contacted by a pin 108, which is moved on operation of the diaphragm release trigger. The lens mount comprises a sleeve 114 which is secured by a projection 116 to the plunger housing 102, a tube 122 carrying lens 121 being fixed to a sleeve 115 which is threaded to a rotatable, but not axially movable, focusing ring 125. The sleeves 114, 115 have three pairs of co-operating V-grooves, there being interposed between each such pair a guide rod, such as 110, whereby relative axial movement of the sleeves is permitted while relative rotation thereof is prevented. The three guide rods are prevented from axial displacement as by an abutment 129 on the sleeve 114. Rod 110 is provided with a quadrilateral bore in which fit similarly cross-sectioned rods 130 and 130a. Rod 130 is fixed to a lever 109 which is rotated by the plunger 106 on operation of the diaphragm release trigger in the camera 104, the resulting rotation of the rod 110 being communicated to the rod 130a which ends in a lever 132. This lever is normally spring-urged at 133, Fig. 7, so that a lug 134 thereon blocks movement of a part 135a of a pre-set diaphragm 135 but on rotation of the rod 130a the part 135a is released and the diaphragm operates to provide an aperture of pre-selected size. Alternatively, the setting movement may be transmitted by axial displacement of a guide rod. Further, the guide rod may have an axial bore for receiving an electric wire or wires effecting an electric connection between electrical circuit elements for control of the objective setting means.