GB1194652A - Heat Treatment Furnace - Google Patents

Abstract

1,194,652. Interconnected door operating mechanisms. ALCO STANDARD CORP. 23 Sept., 1968. 'No. 45120/68. Heading E2M. [Also in Divisions F3 and F4] A heat treatment furnace of the type disclosed in Specification 1,128,769, having an inner heat insulating door and a co-operating outer vacuum sealing door, closing its charging aperture is modified so that the inner door starts to open a little after the outer door has started to do .so, whereby the sealing gasket 26 around the periphery of the outer door is always shielded from the direct furnace heat. Movement of 'the outer door 25 is derived from an "hydraulic actuator (not shown) and transmitted through, .rod 33. This 'rod is attached to rectangular 'frame 35 which runs in vertical side channels 39 and is itself attached to door 25 through pivotable parallel linkages 40. Door 25 from its open position is closed and sealed against furnace walls 19 around aperture 21 by downward vertical .movement of rod 33, frame 35 and door 25 until the bottom edge of door 25 abuts stops 45 secured below aperture 21. Further downward movement of rod 33 and frame 35 then causes linkages 40 to pivot clockwise about pins 41, and in the manner of a toggle to press door 25 and its gasket 26 against the walls 19. Opening of the door 25 effected in the reverse sequence. The inner insulating door 24 is secured to door 25 through U-shaped lost motion connecting members, the short limbs 47 of which are secured by screws 49 to door 24, and the longer limbs of which are .attached to door 25 by screws 51 which pass 'through elongated upright slots 52 in the longer limbs. When in response to initial upward movement of rod 33, door 25 is drawn horizontally away from aperture 21, door 24 is therefore likewise drawn away from the aperture 22 which it covers. The initial upward movement of door 25 however 'leaves door 24 unaffected since the screws 51 secured to the door 25 merely slide 'upwardly in the .grooves 52 of the U- shaped members. After a predetermined .upward movement of door 25 however, screws 51 abut the top edges of the grooves 52, so that the U- shaped 'members and door 24 are then lifted with door 25 to (he open positions uncovering apertures 21 and 22. Both doors 24 and 25 will move downwardly together on initiation of the closing operation, until the lower .parts 48 of the U-shaped members abut the bottom edges of aperture 21, when they and the inner door 24 will stop .moving, the screws 51 'sliding downwardly in the grooves 52 as outer door 25 completes its downwards movement. Both doors then move in unison horizontally to press against the edges of their respective apertures 21 and 22.