Welding method and apparatus

1. An apparatus for welding closed one end of each of a multiplicity of open-ended tubes suitable for use as brachytherapy capsules, said apparatus comprising:

a welding station having a welding position for welding closed one end of a tube;

a rotatable platform having an outside edge;

a plurality of tube holders positioned adjacent said outside edge of said rotatable platform, said plurality of tube holders movable between a loading position and said welding position, each said tube holder of said plurality of tube holders further comprising means for releasably engaging a tube comprising a block slidably mounted in a recess in a holder support, said block being biassed outwardly by resilient means retained between said block and said holder support;

a feed line positioned in overlying registry with one of said plurality of tube holders at said loading positions;

a feeder for feeding the multiplicity of tubes in a continuous stream, said feeder further comprises an elongate passageway for receiving the tubes end-to-end therein and a restraining member for releaseably engaging the lowermost but one tube within said passageway; and

means for agitating the tubes in said feeder.

2. The apparatus of claim 1 , wherein each said block is retained on said holder support by bolts passing through said block and engaging in said holder support, the block being biassed outwardly by the resilient means, and the bolts retaining the block on the holder support against the resilient bias and thus serving to define the open condition of the respective holder, which can be varied by tightening or loosening said bolts.

3. The apparatus of claim 1 , wherein a set screw is provided in each said recess, each said set screw defining a point beyond which said bolts may not be tightened.

4. The apparatus of claim 1 , further comprising a slide plate along which a tube is slid while being conveyed by one of said plurality of tube holders, wherein said slide plate defines a cut-out region at a release position so as to allow the tubes to fall therethrough.

5. An apparatus for welding closed one end of each of a multiplicity of open-ended tubes suitable for use as brachytherapy capsules, comprising:

a welding station where one end of the tube is welded closed in a welding operation;

a holder support defining a recess;

a holder mounted on said holder support, said holder comprising a block slidably mounted within said recess of said holder support;

a number of bolts passing through said block and engaging said holder support for retaining said block on said holder support;

resilient means acting between said block and said holder support, said block being biassed outwardly by said resilient means; and

a set screw;

wherein said bolts retaining said block on the holder support against the resilient bias and thus serving to define an open condition of the block, said open condition of said block being variable by means of tightening or loosening said bolts, and wherein said set screw is provided in said recess to define a point beyond which said bolts may not be tightened.

6. An apparatus of claim 5 , wherein said holder is formed from Elkonite.

7. An apparatus of claim 5 , wherein said holder support is formed from Elkonite.

8. An apparatus of claim 1 , wherein at least one of said plurality of tube holders is formed from Elkonite.

9. An apparatus of claim 1 , wherein said holder support is formed from Elkonite.