Patent GB-1480470-A (GB)
Title: Apparatus for screwing caps on containers
IPC: B67B3/20
Filed: 1976-03-04
Abstract: 1480470 Applying screw caps HORIX MFG CO 4 March 1976 [14 Oct 1975] 08747/76 Heading B8T Apparatus for applying a screw cap to a container by means of air pressure actuated gripping means includes a pneumatic system for the release of air pressure to the gripping means in response to the torque on the gripping means. The apparatus includes a housing 2, open at the bottom, and continously rotatable about a vertical axis by a shaft 1. Within the housing is a central vertical shaft 5, rotatable in opposite directions a few degrees relative to the housing, and rotatable with the housing via an arm 22 fixed to the shaft 5. The ends of the arm 22 engage compressible means, e.g. a piston and cylinder 23 fixed to the housing. The shaft 5 is connected by a flexible coupling 6 to a shaft 7 carrying a chuck 18 at its lower end. An air pressure actuated gripping ring 19 is positioned within the chuck. In operation, air pressure is supplied to the piston and cylinders 23 to rotate the arm 22 intially relative to the housing, and subsequently with the housing. The rotation of the arm 22 and thus shaft 5 causes a stop 58 on the coupling 6 to engage a slide in a valve to move a closure 53 away from a bleed passage in the valve which is connected via lines 47, 51 to the air source. The air source is also at this time connected to a valve 30 at its inlet 31, the inlet/ outlet 33 of the valve 30 being connected to the inlet of a valve 37 in the chuck, which valve 27 is exhausting to atmosphere. As the housing moves down to engage a cap to be applied, contact with the cap causes a button 43 connected to the valve 37 to move the valve 37 to connect the inlet thereof to its inlet/outlet 38 whereby air pressure is applied via a valve 21 to contract the gripping ring on to the cap. The cap is then applied to a container, at which time the chuck moves upwardly relative to the housing and when the torque at the ring 19 overcomes the air pressure, the arm 22 slides in the cylinders 23 and the chuck stops rotating. When the chuck and shaft 5 stop rotating, the stop 58 ceases to act on the closure 53 which then acts to close the bleed passage which causes a pressure build-up in the line 47. This pressure build-up acts on a pilot valve 45 to move the piston 46 thereof which acts on the valve 30 to shift connection of the inlet/outlet 33 from the air pressure source to the exhaust 34. The pressure thus drops in the valve 37 and valve 21. The valve 21 includes a floating valve member which is lifted as the pressure in the line 20 to the gripping ring 19 exceeds the pressure in the line 39 to the valve 21, which causes the pressure to the ring 19 to exhaust via line 65 and thus the ring resumes its natural state and the cap is released. Release of the cap returns the valve 37 to its condition of exhaust. Movement of the housing in an upward direction causes resetting of the valve 30 via a button 61 acting on the slide of valve 30. The chuck 18 is preferably mounted in the housing opening by means of a plug 15 having a downwardly tapered surface which seats or a tapered surface surrounding the opening. By this arrangement the apparatus can apply caps to containers which are not axially aligned with apparatus since the chuck is free to move laterally when raised relative to the housing.