Patent GB-706132-A (GB)
Title: Improvements in or relating to method and apparatus for making pipe from concrete and like materials
IPC: B28B21/24
Filed: 1951-08-30
Abstract: A concrete pipe spinning machine, wherein the pipe is formed by simultaneously spinning, packing and vibrating the concrete, comprises a driven hollow cylindrical moulding element 55 adapted to receive concrete and mounted on a stationary support frame, a roller element 95 extending into the moulding element and adapted to bear against the concrete and a high frequency vibrator operatively associated with one of the said elements and adapted to cooperate therewith to pack the concrete.  The invention is also applicable to lining metal or other pipes with concrete.  The mould 55 normally rests on trunnion rollers 19a, 27a at one end and 19b, 27b at the other end, 19a and 19b being on an axle 17 driven by a motor 21 and 27a, 27b being idlers.  The trunnion rollers are fitted with pneumatic tyres to reduce vibration and noise.  The mould 55 is of light construction for use with the pneumatic tyres, having a double shell for rigidity. Circumferential guides 57 prevent lateral displacement of the mould, which is held down on the trunnion rollers by stabilizer rollers 37a, 37b, 43a, 43b, also fitted with pneumatic tyres and rotatably mounted on arms 35a, 35b, 41a, 41b.  The arms are raised to place the mould in position by hydraulic rams 45, 51, and by their means the spinning mould may be held down at the desired pressure.  By adjusting the inflation of the tyre compensation can be made for moulds not truly cylindrical.  Instead of a mould a pipe to be lined with concrete may be placed in the machine.  The action of the roller 95 in addition to the centrifugal spinning of the concrete permits a lower speed of rotation and a higher proportion of cement to water in the mixture.  The ends of the roller 95 normally rest through rubber collars 99, 100 on rings 56 at the ends of the mould and the roller thus rotates as the mould rotates.  The roller 95 can be raised and lowered by arms 74, 82 fixed to a rock shaft 70, which is rocked through a crank 117 by a hydraulic ram 116, whereby the pressure of the roller on the concrete in the mould can be varied. The arm 74 carries a shaft 76 at the end of which is a rubber wheel 80 on which rests an end piece 98 of the roller 95, and the arm 82 similarly carries a shaft 88 with a rubber wheel 90 on which rests an end piece 96, the wheels 80 and 90 having ball bearings to allow free rotation of the roller.  Another hydraulic ram 92 is employed in connection with an arrangement to allow the mould to be removed without disturbing the roller.  In this arrangement, Fig. 7, an arm 86 is interposed between the roller shaft 88 and the arm 82, to which it is pivoted at 87 and operation of the hydraulic ram 92 moves this arm 86 and with it the shaft 88, the wheel 90 thus moving clear of the roller end piece 96 so that the weight of the roller can be taken by the other end piece and it is possible to swing the shaft 88 clear.  This may be done by swinging the arm 86 about a pivot pin 84, so leaving a space for the endwise removal of the mould. Electrical vibrators 107, 108 of conventional design, with a vibrating frequency of about 8,000 per minute, are wedged inside the roller 95 by wedges 111, 112 and supplied with electrical power through <PICT:0706132/III/1> <PICT:0706132/III/2> <PICT:0706132/III/3> <PICT:0706132/III/4> <PICT:0706132/III/5> <PICT:0706132/III/6> <PICT:0706132/III/7> bearing against the mould 55, Fig. 16.  In this case the vibrators are of the rotary unbalanced mass type, Fig. 15, comprising a weight 134 eccentrically mounted on a shaft 124 and an outer shell 133 freely rotatable on the same shaft.  The shaft 124 is rotated through belts 132 from a motor 129 and the rotation of the weight 134 imparts vibration to the shell 133 and thus to the mould. The shaft 124 is mounted in rubber mounted bearings 125 at the ends of arms 120, 121, 122 which extend from a sleeve 119 on the rock shaft 70.  A crank 123 on the sleeve 119 is connected to a hydraulic ram 127, a cable 109 with a suitable connector.  The rubber wheels 80, 90 keep the vibrations from being transmitted to the frame of the machine.  Instead of vibrators inside the roller 95 there may be vibrators 126 disposed below and by the operation of which the vibrators 126 can be raised and lowered and their pressure against the mould 55 controlled.  With this alternative the mounting of the roller 95 can be simpler and it may house a brake shoe which may be expanded by hydraulic pressure to prevent rotation of the roller 95 which then acts as a trowel.  The hydraulic ram 116, instead of being connected to the end of a crank 117, may be connected to the arms 74 close to the shaft 76 and make possible a higher roller pressure. The two means of imparting vibrations may be combined in one machine.