Patent GB-650365-A (GB)
Title: Improvements in machines for the manufacture of concrete blocks, flags, kerbs, slates and similar articles
IPC: B28B3/12
Filed: 1948-12-31
Abstract: 650,365. Apparatus for moulding concrete blocks, slates, &c. BRINDLE, P. Dec. 31, 1948, No. 28744. [Class 87 (ii)] A machine for the manufacture of concrete slates, blocks, and the like comprises a feed hopper, Fig. 2, trays D passing under the hopper, a reciprocating frame B forming guides for and carrying a top and bottom line of rollers C between which lines the trays pass, a cradle 17 to support the bottom line of rollers, and means for reciprocating the frame and rollers to compress the material in the trays. The main frame A of the machine supports the reciprocating frame B and trays D are traversed on a runway E from a feed hopper F, full trays being removed along a runway E<SP>1</SP> on to a pivoted runway G. The contents of the trays are then'removed and the trays transferred to the opposite end of the machine for re-use. The trays D, Fig. 7, are formed as a skeleton frame with wheels 11 running on rails 12 of the runways. Each tray has a loose bottom 13 supported on longitudinals 14 and a loose platen 15 is inserted in the bottom of each tray. A slotted plate 16 is arranged along each longitudinal side of the tray by which it is intermittently traversed through the machine. The frame B, Figs. 9, 10, is carried in a cradle 17 riding on rollers 18 in a second cradle 171 supported by frame A. The cradle 17 and frame B are reciprocated by a connecting rod 19 driven from an electric motor 22. The bottom line of pressure rollers C is supported on the roller spindles C<SP>1</SP> by the cradle 17, and the upper line of rollers rests on the lower line with spindles c passing through vertical slots in the frame B. Tension springs 26 connecting yokes 24 may be varied in tension by a pivoted lever 27 which allows the pressure between the lines of rollers to be varied by varying the pass between them. The trays are fed intermittently along the runways E by flat rods D<SP>1</SP> engaging the slots in the plate 16. During the passage of the trays between the rollers C they are prevented from rearward movement with the frame B by stops e. A check.plate 28, Fig. 9, is mounted on rollers 29 engaging slots 30 in a stationary plate 31 carried by a bracket A<SP>1</SP> supported by the frame A. The plate 28 is slotted along its upper edge to correspond with the plate 16 and is urged upwards into engagement therewith by springs 32. The end of the plate is inclined and engages a roller 33 carried by the plate 31. The trays D are thus held stationary as frame B reciprocates to the right, the stops e, Fig. 2, preventing rearward movement. As the frame B returns to the left a projection 34, Fig. 11 (not shown), engages a projection 35, Fig. 9, on the rods D<SP>1</SP> to carry the rod and the trays D towards the runway G. As rod D<SP>1</SP> is moved a cam surface 36 depresses the plate 28 and releases the trays which are traversed a predetermined distance by the projections d. On the return stroke to the right the frame B engages a lever 37 to retract the rod D<SP>1</SP> so that the rod is in position for the next forward stroke. In the manufacture of slates concrete is fed to the trays D by a feed roller 38 rotated by projections 39 engaging the plate 16, and a smoothing roller 40 may be provided. The trays advance intermittently and receive a coating layer of dry colour and cement from a shoot 41, a doctor blade 42 levelling off the colour. The trays then advance to the rollers C, the upper line of which reciprocate over the upper surface of the trays while the lower line reciprocates under the tray bottom to prevent buckling. An endless band 43 acts as a track for the upper line of rollers and produces a level polished surface. As the trays emerge 'from the rollers, punches 50, Figs. 12, 13 (not shown), actuated by rods 51 mounted on the frame A, are operated at each reciprocation of the rod 19 by a rod 51a and a crank-lever 54 to pierce holes along one edge of each slate. A guillotine 52 inserts two transverse nicks in the concrete in each tray to enable the concrete to be afterwards severed into slates. Further holes are punched in line with the nicks but these are removed by the severing. When not required the downward movement of the guillotine is prevented by vertical rods 53 which engage the plate 16 instead of passing through the spaced holes therein. The tray D then passes to the end of the runway El which terminates in a pivotable platform, carried by the pivoted runway G which may be raised or lowered by a connecting rod 57. As the left-hand of G is lowered with a tray thereon the bottom of the tray and its contents are deposited on a table 60, the skeleton of the tray is then lowered further. The plate 15 and the concrete thereon may then be removed and the bottom of the tray replaced. As the left-hand end of G is raised the empty tray runs down to the opposite end of G and is held there by a spring catch 63, Fig. 4 (not shown), against buffer springs 61. Platforms at each end of the runway G are linked by rods 65 and levers 66 which prevent them from tipping when in the upper positions. The empty tray at the right-hand end of G is then raised to a position adjacent the runway E, the catch 63 is released and the tray is propelled by the buffer springs on to the runway E. Where deeper trays D are employed for the manufacture of blocks, additional buffer springs 72 may be employed, the roller 38 may be dispensed with, and the material may be tamped by mechanism 170 operated by a rod 174 and levers 172 actuated by the frame B.