Patent GB-788090-A (GB)
Title: Improvements in or relating to the manufacture of asbestos-cement pipes
Inventor: FOURMANOIT ROBERT
IPC: B28B21/48
Filed: 1956-02-25
Abstract: 788,090. Machines for making pipes. ETERNIT SOC. PER AZIONI. Feb. 25, 1956, No. 5949/56. Class 99(2). A machine for the continuous manufacture of asbestos-cement pipes comprises two pipeforming units 4, 4A in series and fed by a felt 1 which moves continuously so that the asbestoscement layer carried thereby is transferred without interruption to mandrels placed in timed relation in one or other of the units There is an upper felt 1A common to both units and operated by at least one drive roller for each unit, that roller being located opposite or behind, the mandrel on which a pipe is to be formed. Apparatus. As shown, this comprises lower and upper felts 1, 1A, a vat 2 containing a liquid asbestos-cement mixture, a cylinder 3 and two pipe-forming units 4, 4a including rollers 5, 5A, pressure rollers 18, 18A driven through bevel gears and clutches by motors 19, 19A, and fork stops 20, 20A for holding in position the mandrels on which the pipes are formed. Mandrels to be fed to the units are stored on an inclined track 6 having stops 7, and a track 8 provided with stops 9 carries mandrels passing from the unit 4 and the track 6 ; mandrels having pipes thereon are discharged onto a track 32. Pairs of chains or link belts 10, 10A having catches 11, 11A, 12 and 12A and pairs of idling rollers 13, 13A for carrying the mandrels are driven by motors 14, 14A and tensioned by rollers 15, 15A mounted on levers 16, 16A operable by the raising and lowering of rods 17, 17A fixed to or operated by the units 4, 4A. Disposed below the felt 1 and parallel to the roller 5 is a pipe 31 connected to a supply of water controlled by a valve operated by the lifting of the pressure rollers 18, the pipe being provided with nozzles to release water in the form of a sheet to cut the asbestos-cement layer at the point where that layer becomes detached from the felt when the mandrel 27 in the unit 4 is lifted. Operation. As shown, mandrels 25, 26 on the track 6 await advancement into the units 4 or 4A, while a mandrel 29 carrying a pipe formed in the unit 4 and a mandrel 28 that is to be advanced into the unit 4A are located on the track 8 between the units. A mandrel 27 is located in the unit 4 the rollers 18 of which are raised, and a mandrel 30 on which a pipe is being formed is located in the unit 4A. Before the pipe in the unit 4A is of the required thickness, the rollers 18 of the unit 4 are lowered this movement operating automatic devices remotely controlling the engagement of the clutch or the starting of the motor 19 to drive the rollers; when the rollers 18 contact and rotate the mandrel 27 which is supported on the rollers 13 of the chain 10, the rod 17 acting on the lever 16 lifts the roller 15 so that the mandrel is moved downwardly into contact with the asbestos-cement layer on the felt 1 and a pipe is then formed on the mandrel. As soon as the pipe being formed in the unit 4A reaches the required thickness the rollers 18A of that unit are raised thereby operating, through the rod 17A, the roller 15A which tensions the chain 10A to lift the mandrel 30 from the felt 1 ; automatically, the motor 19A is stopped and the clutch associated therewith is disengaged, and the motor 14A is started to drive the chain in an anticlockwise direction, as seen in Fig. 1, 'so that the mandrels 29 and 30 having pipes thereon are discharged by the catches 11A, 12A of the chain onto the track 32. The mandrel 28 which has rolled along the track 8 to the position previously occupied by the mandrel 29, is then caused by the catch 12A to move forward into the unit 4A, and the motor 14A is stopped. When the pipe being formed on the mandrel 27 has reached the required thickness, the rollers 18A of the unit 4A are lowered and the rollers 18 of the unit 4 are raised ; in the latter case, the rod 17 causes tensioning of the chain 10 to lift the mandrel 27 from the felt and during this operation water from the nozzles in the pipe 31 cuts the asbestos-cement layer still connected to the pipe on the mandrel 27 as the latter is lifted. Again, raising of the rollers 18 automatically stop the motor 19 and disengages the associated clutch, and starts the motor 14 to rotate the chain in an anti-clockwise direction so that the mandrel 27 is carried by the catch 11 onto the track 8 and simultaneously the mandrel 26 is carried onto that track to be deposited against the mandrel 27, and the mandrel 25 is advanced into the unit 4. After a full pipe-forming cycle has been accomplished, the rollers 18A of the unit 4A are depressed so that the mandrel 28 comes into contact with the felt 1 to begin a new pipe-forming cycle. The rollers 22, 24 of the felt 1A may be driven.