Patent GB-385087-A (GB)
Title: Improvements in or relating to machines for closing cans and the like
IPC: B67B3/24
Filed: 1931-11-27
Abstract: 385,087. Sealing cans in vacuo.' METAL BOX CO., Ltd., 28, Kingsway, and STUCHBERY, A. L., Chequers Works, North Circular Road, Palmer's Green, both in London. Nov. 27, 1931, No. 32977. [Class 125 (ii).] A machine for closing cans &c. comprises a rotary valve 1 including a plurality of chambers 8 mounted in a cylinder 10 and means disposed in each chamber for effecting a closuring operation in each chamber at a predetermined point of the path of travel of the valve, the cylinder being provided with inlet and discharge openings for the cans, &c. and with means for providing, before closuring is commenced, a predetermined condition of atmosphere in the chamber. As shown, the valve 1, which is secured to a shaft 2, has five chambers 8 and is mounted in a conical cylinder 10. Between the inner cylinder wall 11 and the outer wall 12 are jacket spaces, separated by a web, which spaces are connected to sources of vacuum and inert gas respectively and into communication with which the chambers 8 are brought as the valve rotates. The head of the valve is formed as a well 45 for oil which overflows between the conical faces and provides a liquid seal. Cans are fed into and out of the chambers by rotating arms 21. The cans are held in place by a centring plate 22 and a spring-andcam controlled finger 23. Each capping head comprises a tampion 30 secured to the end 31 of a spindle 32 by a screw 33. The spindle is pivoted at 34 to an arm 35 hinged at 36 to a boss on the valve shaft 2. Each of the arms carries at its. extremity a roller 37 running on a cam track 38 carried on the cylinder 10. At the capping point a depression 38a is formed in the cam track, in the form of a groove, which effects positive lowering and raising of the capping head. The spindle 32 is mounted in a sleeve 39 carrying a collar 40 and a housing 41 for a chuck 29. At the depression 38a the spindle and sleeve descend and the collar 40 engaging the top 8a of the valve chamber 8, the spindle descends relatively to the sleeve and contracts a spring bracket 42, thus securing the skirt of the cap to the can. To prevent the cap being prematurely applied when the chamber 8 reaches the space 14 and inert gas is admitted, a magnetic plate 44, magnetized by a coil 43, is secured in the capping head and the coil is energized through a brush carried by the associated arm 35 and making contact with a supply segment at a point just before the space 14 is reached. At this point also the cam track 38 dips and rises, thus allowing the cap to be removed. Means may be provided for preventing admission of inert gas to an empty chamber. Such means may comprise a disc 47 rotating clockwisely and synchronously with the valve 1 and carrying a number of pivoted switch members 48 mounted in slots. To a spindle 51 are secured arms 50, 52. The arm 50 is maintained across the path of the cans by a spring (not shown) and when a can engages it and swings it around, the arm 52 is swung into the path of the switches which are thus turned on their pivots and set for engagement with a contact 55. An electrical circuit is thus completed, a solenoid is energized and a gas valve is opened. There are as many switches as there are chambers in the valve and if there is no can fed to engage the arm 50 no gas will be admitted to the chamber which would normally receive the can. Alternatively an electrical circuit may be completed by a plunger pushed against a contact by the can in the chamber. When inert gas is not used the cans may be subjected to two evacuations. Specifications 255,632, [Class 125 (ii), Bottles &c., Filling &c.], and 355,397 are referred to.