GB412854A - An improved internal form for conduits, sewers and the like - Google Patents

Abstract

412,854. Casting conduits in situ. DORAN, W. E., 26, Courtfield Gardens, Earl's Court, London. Dec. 8, 1933, No. 34575. [Class 20 (ii).] A form for making concrete conduits, sewers and the like comprises a flexible curved member 1 of sheet material supported by an internal framework having expanding and contracting mechanism, the gap between the longitudinal edges 2 of the member 1 being closed by an adjustable shutter 4. In the construction shown, the member 1 is of sheet steel and its longitudinal edges 2 are reinforced by bars 3 which are slotted to receive the arms 9, Fig. 2, of the expanding and contracting mechanism. This mechanism is screwed to a pair of sole-plates 11 of a frame 7 running longitudinally of the member 1, and comprises two end brackets 10 to each of which a pair of arms 9 are pivoted. These arms are adapted to be connected by bolts or bars to angle-brackets 8 mounted on the member 1. To the head 13 of each bracket is pivoted a bell-crank lever 16, the vertical arm of which engages, by a pin-and-slot connection, with a nut mounted on a screw-threaded shaft 12 journalled in both brackets. A pair of vertical arms 20 adjustably engage with a nut 17 mounted in the horizontal arm of each lever, and the upper ends of the arms are connected to the shutter 4. The vertical height of the shutter is adjusted by rotating a handwheel 14 on the shaft 12. The arms 20 each comprise-two spaced bars through which extends a shaft 22 having a handwheel 47. The expansion and contraction of the arms 9, upon rotation of this handwheel, is effected by links 26-29 connected to the arms and to screwed sleeves 23, 25, which are mounted respectively on right and left-handed screw-threaded portions of the shaft. A further sleeve 24 is secured to the shaft and engages in slots 32 of two plates 31, the slotted ends of which engage over pins 46 on longitudinal bars 33 connected to the arms 9. By this means, the shaft 22 is prevented from moving longitudinally. The end of the shaft remote from the handwheel may be coupled to the shaft of adjacent similar mechanism so that a series of forms may be expanded or contracted simultaneously.