GB1302702A - - Google Patents

Abstract

1302702 Impact cutting tools KLARCRETE Ltd 6 Jan 1970 [10 Jan 1969 11 June 1969 26 Nov 1969] 35437/72 35438/72 and 35439/72 Divided out of 1302701 Heading B4C [Also in Division E1] In a machine for cutting an accurate recess 70, Fig. 1, of predetermined contour in a concrete road or runway-e.g. for the reception of lighting or signal apparatus, or of loosely-fitting surface-repair blocks adhered therein, as in the Specification-a power-driven impact cutting unit 34-36, Fig. 2, is traversed continuously over the area 70 by a carriage 33 which is reciprocated along a track 48, the track 48 itself being swung or translated to and fro over the area 70 along a transverse track 42-43 on a frame 30 mounted on the road surface. As shown the area 70 and frame 30 are quadrant shaped, the frame 30 comprising a peripheral vertical rail 42-43 on legs 41 provided with fixed or tiltable road-gripping suction pads. The cutting unit 34-36 comprises a multicylinder pneumatic hammer which " floats " on the road surface. The track 48 comprises a slotted square tube within which the carriage 33 is reciprocated by an external cylinder 38, the cutting unit being carried by a vertically slidable plate 66 passing through the carriage and the tube slots. The tube 48 is supported by rollers 50, 52 and is swung to and fro about a vertical pivot 32 by a cylinder 37. The cylinder 38 may be actuated by trip switches on the rail 42-43. Each suction pad, Figs. 7-9 (not shown), has a suction pipe (104) and comprises a metal base-plate (100) provided with a depending flange (101) enclosing a soft outer and hard inner annular seal (102, 103) which are successively pressed against the road surface until the flange 101 seats thereon. The seals shown comprise bands of foam and hard rubber, but the outer (foam) seal may be replaced by an inflatable tube. In a modification a machine, Figs. 4-6 (not shown), for cutting a rectangular recess with rounded corners comprises a main carriage (77) which is reciprocated on slide bars (76) and carries a pair of bars (78) providing a transverse track for an auxiliary reciprocable carriage carrying a hammer unit (80) whose descent is controlled by a dash pot (81). The actuating cylinders may be controlled by undisclosed means so that the cutters not only reciprocate over the whole area but also trace out paths along the sides and ends of the rectangle. It is stated that (a) the machine of Figs. 4-6 may be enlarged and comprise several hammer units so that it may be used preparatory to resurfacing a road; (b) the machine may be displaceably mounted on a transport vehicle and be either weighted or pegged to the road.