Patent GB-1206703-A (GB)
Title: Apparatus for and method of testing covers for cans or the like
IPC: G01M3/04
Filed: 1968-11-12
Abstract: 1,206,703. Testing can covers. BORDEN Inc. Nov.12, 1968 [Feb.12, 1968], No. 53457/68. Heading G1S. Apparatus for testing can covers comprises, a rotatable sleeve 37, Fig.4, carrying a valve plate 34 and its support 36, a duct 42 supplying gas under high-pressure e.g. 80 p.s.i. through pipes 59 to valves 60, a toothed ring 47 rotatable by gearing and carrying the valves 60 which are operated as their sliding spools 65 come into contact with cams 71 and 75 mounted on a fixed support 72, an annular support member 76 secured to the sleeve 37, and test unit cells each adapted to be divided by a cover into two chambers and to be opened and closed by a shaft 85 reciprocated by a roller 106 engaging a fixed cam 20. A high-pressure gas pipe 95, Fig. 3, is connected to the upper cavity 92 of each cell unit and with a pressure relief valve 114 connected to bores 116 in the rotary valve 34, and a stationary valve 30 having bores 117,118 and 119 is provided with an electric transducer 120 which is connected to an amplifier 122, so that a build up of pressure due to a leak through the cover is sensed by the transducer and arranged to operate a solenoid control valve 124. When the valve 124 operates, gas is supplied to a piston and cylinder 129 to move a bell crank 131 and depress one of a series of upstanding pins 134 in a memory wheel 133 rotating on a driven shaft 56. The wheel 133 rotates in timed relationship with the movement of the rotary valve bore 116 of each test unit and the depression of one of these pins serves to record a leak fault in the cover being tested. In operation the apparatus 11, Fig.2 (not shown) driven by a gear wheel (159) directs covers into the cells of the various test units which are closed by over-centre linkage operated by the rollers 106 and cams 20. Each spool valve 65 in turn then encounters a cam 75, Fig.3, and is moved to pass gas into the lower cavity 83 of its cell. At the same instant the bore 116 is aligned with an upper bore 117 and the upper cavity 92 opened to atmosphere. The high-pressure gas is then able to flex the cover upwardly but any pressure above the cover is negligible due to the venting to atmosphere. Having compensated for the flexing of the cover the bore 116 is aligned by further rotation of the valve plate 30 with a bore 118 so that any build up in pressure in the upper cavity 92 due to high-pressure gas leaking through the cover from cavity 83 is sensed by a transducer 120, the signal being amplified at 122, Fig.4, to operate a valve 124 and the cylinder 129 to press down a pin 134 in the memory wheel. The spool valve 65 then engages a cam 71 and is shifted to exhaust the cavity 83. At the same time the upper cavity 92 is also vented. The cell is now opened by upward movement of the shaft 85 induced by the cam follower 106 and the support member 76 rotates the cell into a position adjacent the sorting apparatus 12, Fig. 6. In a modification, lowpressure gas may be injected into 92 during opening to ensure that the cover as held down on rim 82. A pair of wedges 138, 139 lift the cover off the rim 82 of the cavity 83 and place it on a circular guide 140, and a disc 168 fixed to the shaft 156 has a plurality of pins 169 which engage and advance the covers as they are removed for collection. A cam 148 on an arm 147 of a blade 144 lies in the path of travel of any pin 134 previously depressed in the wheel 133 as a result of detecting a leaky or faulty cover, so that when the pin encounters the cam 148 the arm is swung in a counter-clockwise direction to swing aside a flange 170 and a curved section 143 to direct the faulty cover into a reject chute 149.