GB1389395A - Fastener tool - Google Patents

Abstract

1389395 Torque wrenches ROCKWELL INTERNATIONAL CORP 23 March 1973 [11 May 1972] 14082/73 Heading B3N The operation of the torque wrench is the same as that in Specification 1,367,201. A motor 22 drives an output member 28 through a clocktype spring 105. A torque responsive shut-off mechanism 30 for terminating air flow to the motor. This is achieved by pawl 128 moving out of engagement with valve stem assembly 126 so that fluid pressure on valve member 58 moves it forward to stop fluid flow from chamber 54 to passage 62. A signal generating mechanism 32 includes a valve assembly 150 normally biased to the position shown in Fig. 1. During running of the motor this position is retained by fluid flow along passage 62 to the right hand side of valve member 156. When valve 58 is closed fluid flow to this side of the valve member is stopped although fluid can still flow along passage 176. This causes the valve member to move against its spring bias to shut off vent passages 170, 172, 174 and allow fluid flow to air supply line 166. Fluid thus passes to a marking unit 34 to propel a small amount of marking ink on to the fastener. The tool 2A of Fig. 4 works in the same manner but is provided with means of producing a signal indicative of the length of time for which a fastener is tightened. This means are reed switches 222, 224, reed actuators 226, 228 and a timer which is an R-C timing circuit including a resistor 230 and a capacitor 232. The right hand ends of the actuators are magnetic so poled that displacement of the actuators to the right causes the switches to move from their full line positions to the dotted positions. In operation actuation of lever causes fluid to move actuator 226 so that the timer unit is started. This is achieved as the right hand side of actuator 226 is vented whilst both sides of actuator 228 receive fluid. When the predetermined torque is reached valve 58 closes and the downstream side of the valve is vented through the motor. Thus actuator 228 is moved against its spring and the timer is stopped. Read out from the timer can take a number of forms.