IMPROVEMENTS IN SCABBLING APPARATUS

Abstract: There is described apparatus for scabbling concrete in which the cylinder block which has a plurality of scabbling bit-carrying pistons mounted for reciprocal movement with­ in a frame such that it is free to move within the frame in the direction of reciprocation of the piston.

Description: Improvements in Scabbling Apparatus" Background of the Invention This invention relates to apparatus for scabbling concrete. Apparatus for scabbling concrete includes a cylinder block having a plurality of piston and cylinder devices and fluid inlet and outlet means whereby the pistons, equipped with scabbling bits, are caused to reciprocate relative to the cylinders thus to scabble the surface on which the apparatus rests. Generally, the cylinder block is rigidly attached to an operating handle, and to facilitate movement, groundwheels are provided. Reciprocation of the pistons and their impact against the surface being scabbled result in vibrations in the operating handle. Such vibrations cause the apparatus to be difficult to use and cause discomfort to the operator. Summary of the Invention It is an object of the present invention to obviate or mitigate the above disadvantages. According to the present invention there is provided apparatus for scabbling concrete comprising a frame, a cylinder block having a plurality of scabbling bit carrying pistons mounted for reciprocal movement therein, the cylinder block being mounted within the frame such that the cylinder block is free to move within the frame in the direction of reciprocation of the pistons. Further according to the present invention there is provided apparatus for scabbling concrete comprising a chassis, a cylinder block having a plurality of scabbling bit carrying pistons mounted for reciprocal movement therein, the chassis being provided with groundwheels or the like, a cross member connected to said chassis and a support attached to said cross member for supporting the cylinder block such that the cylinder block is free to move relative to the chassis in the direction of reciprocation of the pistons. Preferably, said support includes means for moving said cylinder block between a lowered in-use position and a raised out-of-use position. Description of the Drawings Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a side elevational view of one embodiment of scabbling apparatus made in accordance with the present invention; Fig. 2 is a top plan view of the apparatus of Fig. 1; Fig. 3 is a side elevational view of a hand-held embodiment of scabbling apparatus made in accordance with the present invention; Fig. 4 is a top plan view of the apparatus of Fig. 3; Fig. 5 is a side elevational view of another embodiment of scabbling apparatus made in accordance with the present invention; Fig. 6 is a top plan view of the apparatus of Fig. 5; Fig. 7 is a part sectional side elevational view of a further embodiment of scabbling apparatus made in accordance with the present invention; ; Fig. 8 is a part broken-away plan view of the apparatus of Fig. 7; and Fig. 9 shows the scabbling apparatus of Fig. 7 fitted with a cover. Description of the Preferred Embodiments Referring to Figs. 1 and 2, apparatus for scabbling concrete is indicated generally at 1 and includes a scabbler 10 having a cylinder block 11 provided with reciprocating pistons 12 carrying scabbling bits 13. Compressed air for operating the scabbler 10 is fed to the cylinder block 11 via a manifold 14, connecting pipes 15 and control lever 16. The scabbling 10 is reciprocably mounted within a rectangular frame fixed to an axle beam 21 by means of brackets 22. Wheels 23 are mounted on the axle beam 21 on appropriate axle shafts. Optionally, a pair of front wheels 24 may be provided on members 25 fixed to the frame 20. The cylinder block 11 of the scabbler 10 is provided with a top plate 31 which serves also to limit the downwards movement of the scabbler 10 within the frame 20. Control of the scabbler is effected by means of a control valve 17 located on a handle 30 fixed to the axle beam 21. The control valve controls the compressed air supply to the connecting pipes 15. Since the scabbler block 11 is free to move in a vertical direction relative to the frame 20, vibrations whch occur during scabbling are not transmitted to the operator-held handle 30. Referring now to Figs. 3 and 4, hand-held scabbling apparatus 40 has a cylinder block 41 mounted in a frame 112. The block 41 has a plurality of pistons 52 having scabbling bits 53 and mounted for reciprocating movement within the block 41. The frame 42 comprises a chassis 43 having castors or wheels 44 adapted to engage the surface being scabbled, side members 45 and a cross member 46 to which handles 47 are fixed. The side members 45 cooperate with protrusions 49 of the block which serve to guide the block constraining its movement in the direction of reciprocation of the pistons. The scabbling unit 41 is resiliently mounted within the frame through coil springs 50 which engage the top surface of the block 41 and the underside of the cross member 46 to urge the block 41 against the surface being scabbled. The scabbling block 41 is thus free to move relative to the frame 42 in the direction of movement of the pistons 52 and the vibrations are absorbed by the springs 50. A lead screw 70 is fitted to the block 41 and extends through the cross member 46. A stop nut 71 serves to limit the downward travel of the block 41 within the frame 42. One of the handles 47 is provided with an operating valve 57 for controlling the operation of the scabbling unit 41 via control lever 58, pipe 61 and manifold 62, compress air being fed to that handle via inlet pipe 59. In the alternative embodiment illustrated in Figs. 5 and 6, a scabbler block 110 is reciprocably mounted within a frame 120 which comprises a chassis 121 to which ground wheels or castors 122 are fitted. The chassis 121 has a pair of side members 123 to which a cross member 124 is fitted. The scabbler block 110 is located by means of guides 129 fitted to each side of the block 110 and cooperating with respective side members 123. The interaction of the guides 129 and the side members 123 is such to permit vertical movement of the scabbler block 110 relative to the frame. A support plate 125 which is received in a slot 126 in the cross member 124 provides means whereby the scabber 110 may be moved between a lowered, in-use position and raised, outof-use position. In the in-use position, scabbling bits 113 contact the surface to be scabbled and the scabbler is held against this surface by virtue of its own weight or may be positively urged by means of springs (not shown). In the out-of-use position the scabbling bits 113 are raised by lifting the support plate 125 by means of cross handle 28 and interposing a locking pin (not shown) in a slot 127 in the plate 125 thus permitting the scabbler to be wheeled to and from an operating location. Compressed air is fed to the block 110 via a control valve 137, pipe 115 and manifold 114. In Figs 7 and 8 scabbling apparatus 200 comprises a frame 210 comprising a chassis 211, side members 212 and a cross member 213. The chassis 211 is provided with vertically adjustable wheels 214 mounted on suitable axles 213. Each side member 212 is provided with a V-section portion 215 carrying plastics bearing pads 216 adjustable by means of respective set screws 217 and urged outwardly by compression springs. A scabbler cylinder block 220 is mounted within the frame 210 and is provided on each of its sides with V-shaped guides 221. The pads 216 bear against respective faces of the guides 221 and locate the block 220 within the frame 210 whilst permitting vertical movement of the block relative to the frame. The cross member 213 having a U-section, connects the two side members 212 and provides height adjustment means for the block 220. Such means comprises a lead screw 231 having a lifting block 232 fitted to one end. The lifting block 232 cooperates with top plates 223 of the cylinder block 220 whilst the other end of the lead screw 231 has an adjustment block 233 which engages the cross member 230 thus limiting the amount of downward movement of the block relative to the frame. An extension 236 adjustment block 233 from the cross member 213. Modifications and improvements may be incorporated without departing from the scope of the invention. For example, the four wheels 214 may be replaced with a pair of larger wheels centrally located on the chassis 211. In Fig. 9, the scabbling apparatus is provided with a cover 300 which serves as a sound absorbtion barrier. The cover 300 is fixed to the cross member 213 and can optionally be provided with a skirt 310 which seals the scabbling apparatus against the surface to be scabbled. In this way a vacuum extraction pipe 320 to extract dust etc. from the scabbler apparatus may be provided.

Claims: CLAIMS 1. Apparatus for scabbling concrete comprising a frame, a cylinder block having a plurality of scabbling bit-carrying pistons mounted for reciprocal movement therein, the cylinder block being mounted within the frame such that the cylinder block is free to move within the frame in the direction of reciprocation of the pistons. 2. Apparatus for scabbling concrete comprising a chassis, a cylinder block having a plurality of scabbling bit-carrying pistons mounted for reciprocal movement therein, the chassis being provided with groundwheels or the like, a cross member connected to said chassis and a support attached to said cross member for supporting the cylinder block such that the cylinder block is free to move relative to the chassis in the direction of reciprocation of the pistons. 3. Apparatus as claimed in claim 1 including guide means attached to said cylinder block, said guide means cooperating with upstanding side members of the frame. 11. Apparatus as claimed in claim 3 wherein said guide means is in the form of protrusions extending from the sides of said cylinder block and cooperating with respective edges of said side members. 5. Apparatus as claimed in claim 3 wherein said guide means comprises a V-shaped angle section fixed to the sides of said cylinder block and cooperating with a pair of angle opposed bearing pads fixed to said side members. 6. Apparatus as claimed in claim 2 wherein said support includes means for moving said cylinder block between a lowered, in-use position and a raised, out-of-use position. 7. Apparatus as claimed in any preceding claim and including a cover fitted over the said frame and cylinder block. 8. Apparatus as claimed in claim 7 wherein said cover is provided with a skirt sealing the interior of the cover to the surface to be scabbled.

Inventors: ALLAN, DAVID THOMSON
Applicants: ALLAN, DAVID THOMSON, JOHN MACDONALD & COMPANY (PNEUMATIC TOOLS) LIMITED
Application year: 1982
Main classification: B28D1
IPC codes: E04G21, E04F21, B28D1, E01C23