Patent GB-607766-A (GB)
Title: Improvements in and relating to sealing-in machines for electric lamps and the like
IPC: H01J5/24
Filed: 1943-11-09
Abstract: 607,766. Making electric lamps. BRITISH THOMSON-HOUSTON CO., Ltd. Nov. 9, 1943, No. 18586. Convention date, Nov. 9, 1942. [Class 39(ii)] [Also in Group XL(a)] In a machine for sealing electric lamps, the mount 13, Fig. 2, comprising the filament and flared stem 21 as described for example in Specification 553,184, [Group XL], is positioned by means of the exhaust tube 17 and lead-in wires 18 in the spindle 15 carried by a head 11 mounted on a rotating turret 12, Fig. 1. The head carries a rod 26 on which are secured guides 23 and clamping devices 22, 25 by which the bulb is held with its end against the flanged stem. The turret is indexed through a series of operating stations A-Q, and the head is kept in position for loading and unloading during its transit through the three leading stations A-C and the last two stations P, Q by a roller 52 which engages fixed guides 49, 50 under the turret. For the remainder of the traverse a chain 48 engages a sprocket wheel on the head to turn it about its axis. At the stations D, E, F, G, progressively intense heating is applied to the stem and lower end of the bulb by burners 63, 64 to fuse the glass, and at station H pressure is applied by a cam-actuated rod 69 which raises a sleeve 65 through a spring-controlled rod 66 passing through the head. At J, further pressure is applied by another rod 85, followed by further heating and pressure at K and L respectively. Intense heating at M is followed by diminishing heating at N and O, cooling at P where the head enters the guide to the unloading station Q. The other end may be treated in the same way by a second traverse through the same or another machine. An alternative to the camactuated pressing devices, comprises a fixed cam track on which the spindle support bars, Fig. 9 (not shown), and which is provided with depressions and protuberances to produce the required movements of the stem relative to bulb. Another form of stem support is shown at Fig. 8. To centre a stem which has only a short sealed tubulation, the support has a circular lip; it has also a heat insulating collar 105 of asbestos, and apertures 108 for circulating the heating gases; 107 is the pressing sleeve. The bulbclamping devices 22, 25 are pivoted at 31, 32, Fig. 3, to a bracket 30 secured to the rod 26 and are held in the open and closed position by a rollar 33 carried by a bar 44 and moved to engage a tail piece 35 on the member 25 to open the clamp and held in either position by a spring 36. Centring of the bulb is effected by the engagement of the tail piece 42 of the member 25 with an adjustable stop 43 on the member 22. The Specification as open to inspection under Sect. 91 describes an alternative form of stem support, Fig. 9, (Cancelled) which has a flange 110 against which bears the sleeve 111 for exerting pressure between the stem and bulb; in this form movement of the flange away from the stem is preferable at the heating stations to allow the heating gases access to the underside of the stem. This subject-matter does not appear in the Specification as accepted.