GB949300A - Improvements in or relating to blind-riveting tools - Google Patents

Abstract

949,300. Blind-riveting machines. BRITISH UNITED SHOE MACHINERY CO. Ltd. Dec. 21, 1962 [Dec. 28, 1961], No. 48497/62. Heading B3U. A blind-riveting tool comprises a jack screw device, one member of which is arranged to be driven by power means including a clutch, mandrel-pulling means associated with the other member of the jack-screw device, trigger means to cause the clutch to be engaged, and means actuated by the mandrel-pulling means at the end of its stroke to disengage the clutch and restore the trigger means to its unpressed condition. The main body portion 10 of the tool houses the reduction gearing, clutch and jack screw mechanism and has attached to it a motor, a handle 12 and a detachable nosepiece 14. The nosepiece contains mandrel-engaging jaws 16, a slide bolt 20 and a pull bolt 22 which is secured by a screwed cap 25 to an axially slidable but non-rotatable nut 26. The nut is assembled with a screw 30 and there are friction reducing balls between the two members. Keyed to the screw 30 is a gear-wheel 38 which is in constant mesh with a driven clutch member 60. The driving clutch member 54 is mounted on a splined shaft 52 which is positively driven by the motor through the reduction gearing. The clutch member 54 is actuated by a bell-crank 78 which is linked to a trigger 64 by a vertically sliding member 76. The trigger also operates a normally closed micro-switch 72 and is biased to the " OFF " position by a spring 68. The clutch members have radial inter-engaging teeth and during a rivet-setting operation the torque transmitted by the clutch causes sufficient friction to hold the clutch parts together even if the trigger is released. When the rivet-setting mandrel fractures the reduction in friction allows clutch members to part under the influence of the spring 68 and the tool is switched off. Alternatively, if the nut 26 proceeds to the limit of its travel before the load reduces a cam face 92 on a block 44 attached to the nut engages a face 94 on the vertical member 76 and operates the bell-crank 78 to disengage the clutch, and the trigger 64 to stop the motor. The screw 30 is driven in reverse rotation to return the nut 26 to its starting position by a torsion spring 42 which is tensioned during the working stroke. Specifications 348,818, 405,993, 459,973, 504,928, 578,104 and 587,938 are referred to.