GB2202788A

GB2202788A - Apparatus for cutting channels in walls

Info

Publication number: GB2202788A
Application number: GB08806174A
Authority: GB
Inventors: Robert Brown
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-03-16
Filing date: 1988-03-16
Publication date: 1988-10-05
Anticipated expiration: 2008-03-16
Also published as: GB8706139D0; GB8806174D0; GB2202788B

Abstract

Cutting apparatus includes an elongate frame (10) having two parallel guides (12). A carriage (16) is carried between and tracks said guides (12). A power saw (26) is mounted on said carriage (16) with two disc blades fitted thereto to extend through a slot provided in said carriage (16). Means is provided to secure said frame (10) to a surface in which a 16 channel is to be formed. <IMAGE>

Description

CUTTING APPARATUS This invention relates to cutting apparatus for use in cutting tracks in cementatious material, for example a wall formed from building blocks of concrete or cement bound breeze or pumice particles or other suitable filler material. The tracks are for use in accommodating conduits for electrical or other wiring or other piped or conduited utilities intended to be hidden behind the plastered finished surface of a wall or below the finish screed on a floor.

Heretofore such tracks have been formed by using a power saw with a single disc blade to cut two single grooves side-by-side and then chipping out the land therebetween. This operation suffers from the disadvantages that only carborundum disc blades can be used, since unless the operator has a steady hand and a good eye for and can cut in a straight line, the more expensive diamond tipped disc blades will snap. The carborundum disc blades when used in cutting cementatious material wear very quickly and it is possible that several will require to be used in making such grooves depending on the length required. Also, in cutting the two side-by-side grooves, it is normally not possible for an operator using a manually-held saw to be able to produce two parallel grooves. The further apart the grooves are, the more difficult it is to remove the land therebetween.Further, not only does the disc blade heat up and the cutting operation create a considerable amount of dust, but the time taken to produce such grooves and remove the land therebetween is very timeconsuming.

It is an object of the present invention to provide cutting apparatus which obviates or mitigates the above disadvantages.

In accordance with the present invention, cutting apparatus includes an elongate frame having two parallel guides, a carriage carried between and tracking said guides, a power saw mounted on said carriage with a disc blade fitted thereto to extend through a slot provided in said carriage, and means to anchor said frame to a surface to be provided with a track.

Preferably, the frame has at least two crossmembers to secure the guides in the parallel relationship, one of which cross-members being at or near to one end of the frame. A flexible element preferably connects the carriage to a winding mechanism, the element being entrained around a series of pulleys mounted on said frame. Two pulleys are preferably provided, one roller at the one end of the guides and one roller on the adjacent cross-member, the anchoring mounting of which pulley on said cross-member being in longitudinal alignment with the anchoring mounting of the element to the carriage.

Preferably also, intermediate of the length of the guide on which the roller is mounted, a reel of the winding mechanism is mounted and around which the element is adapted to be wound onto and off. A handle is preferably provided to enable the reel to be rotated to wind the element onto and off so to cause the carriage to be moved longitudinally of said guides.

Preferably further, two disc blades are provided on the power shaft of the saw with the distance therebetween being adjustable to correspond with the required land width between the grooves to be made.

Spray apparatus is preferably provided including one or more spray nozzles connected by piping to a water supply, the nozzle or nozzles being directed onto the cutting operation so as to dampen down and reduce the amount of dust created during the cutting operation.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a cutting apparatus according to the present invention; Fig. 2 is a front view; and Fig. 3 is a side view.

Referring to the drawings, cutting apparatus for use in cutting tracks in cementatious material includes an elongate frame 10 having two parallel guides 12 of C-shape with the open sides facing inwardly towards each other. In this embodiment, the frame 10 is intended for upright orientation for use of the cutting apparatus in cutting tracks in walls. The frame 10 has two crossmembers 14, one at or near to each of the ends of the two guides 12 to secure the guides 12 in the parallel relationship. An intermediate cross-member 8 is spaced from the guides 12 by side arms 6 as shown. One arm 6 is braced at 4 as shown to one of the guides 12. A rectangular carriage 16 is carried between and tracks said guides 12.The carriage 16 has four similar brackets 18, one extending transversely from at or near to each corner thereof and carrying at its outer end two co-axial wheels 32 which run on rails provided inside the guides 12. A slot is provided longitudinally of the carriage 16 parallel with the guides 12 and to one side of carriage 16 as shown. A flexible element 20, such as a wire rope, cord or cable, connects the upper transverse side of the carriage 16 to a winding mechanism 30, the element 20 being entrained around a series of pulleys mounted on said frame 10.Two pulleys 22,24 are provided in the series, one roller 22 at the top end of one of the guides, ie. the left hand one as shown in Figs.1 and 2 of the drawings, and one roller 24 on and mid-way of the top cross-member 14, the anchoring mounting of which pulleys 24 on said cross-member being in longitudinal alignment with the anchoring mounting of the element 20 to the carriage 16.

A power saw 26 is mounted on the outside face (relative to the work surface) of said carriage 16 with two co-axially mounted diamond-tipped disc blades 28 fitted to the output shaft 27 for their cutting portions to extend through the slot provided in said carriage 16 to project beyond said inside face. A guard 35 is provided to encase the portions of the blades 28 on the outside face of the carriage 16.

Intermediate the length of the guide 12 on which the roller is mounted, a reel 34 of the winding mechanism 30 is mounted in a U-bracket 33 fitted around arm 6 as shown, the reel 34 being around which the element 20 is adapted to be wound onto and off. The outer side 36 of the reel 34 is a toothed wheel meshing with a smaller cogged wheel 38 carried at the inner end of a spindle 40 journalled in one limb of the bracket 33. The spindle 40 mounts at its outer end a sprocket wheel 42 around which a bicycle chain 44 is meshingly entrained. The chain 44 is also meshingly entrained around a second sprocket wheel 46 mounted for rotational movement on cross-member 8. A guard 48 secured to cross-member 8 encases the wheels 42,46 and chain 44.A handle 50 is provided secured to wheel 46 to rotate through the gearing above-described the reel 34 to wind the element 20 onto and off so to cause the carriage 16 to be moved longitudinally of said guides 12.

The distance between the two disc blades 28 provided on the power shaft of the saw 26 is adjustable to correspond with the required land width between the grooves to be made. Spray apparatus is provided including one or more spray nozzles connected by piping 54 to a water supply, the nozzle or nozzles being mounted at 56 on the carriage 16 to be directed onto the cutting operation so as to dampen down and reduce the amount of dust created during the cutting operation. An ON/OFF valve 58 in piping 54 is provided on cross-member 8.

Means to anchor said frame 10 to a surface to be provided with a track can comprise any suitable conventional mechanisms, devices or fastenings. The preferable means as used in this embodiment and shown in the drawings comprises an extension 60 being provided to the bottom of each guide 12, the extensions 60 being united with the lower cross-member 14 extending therebetween. The extensions 60 are for length-adjusting the guides 12.

A U-bracket 61, similar to cross-member 8 and side arms 6, is connected between extensions 60 as shown. An axle 62 carrying two wheels 64 is connected by two pairs of links 66 to pivotal mountings 68 provided on the lower cross-member 14. A piston and cylinder arrangement 70 is provided to extend downwardly with the distal end of the piston connected to axle 62 and the cylinder anchored by bracket 72 to bracket 62. The outer end of the cylinder mounts an oil reservoir 74 operated by a hand lever 76.

In use, the apparatus is located against a wall in which a track is to be cut. The hand lever 76 is pumped up and down to extend the piston and cause the axle 62 to move downwardly till the wheels 64 abut the ground with the top cross-member 14 abutting the ceiling joists. The frame 10 is then jammed into position. The saw 26 is connected to a source of electricity and piping is connected to a water supply. The spacing between the two blades 28 is adjusted, if required, and the saw 26 switched on. The carriage 16 is positioned at its uppermost position between the guides 12. The blades 28, although initially spacing the frame 10 from the wall, cut into the wall forming two grooves therein.

By rotating the handle 50, the carriage 16 and saw 26 can be progressed down the wall forming the grooves as it moves down. With the spray apparatus switched 'ON', water will be sprayed as the blades 28 are cutting into the wall, thereby dampening the dust created and also dissipating the heat created in the blades 28. After the grooves are cut, the frame 10 is removed by the hand lever 76 being moved to release the air pressure on the oil allowing it to flow back into the reservoir and retract the piston. The land between the grooves is then chipped out to form the track. The controlled movement of the saw 26 during cutting operations means that diamond tipped disc blades 28 can be used with the known benefits to be derived from such use. In a simplified modification of the invention, only one disc blade can be used if only one groove is required, or in the event of a blade being available giving a groove equivalent to the width of track required.

Variations and modifications can be made to the invention exemplified above without departing from the scope of the invention.

Claims

CLAIMS:

1. Cutting apparatus includes an elongate frame having two parallel guides, a carriage carried between and tracking said guides, a power saw mounted on said carriage with a disc blade fitted thereto to extend through a slot provided in said carriage, and means to secure said frame to a surface to be provided with a track.

2. Cutting apparatus as claimed in Claim 1, wherein the frame has at least two cross-members to secure the guides in the parallel relationship, one of which crossmembers being at or near to one end of the frame.

3. Cutting apparatus as claimed in Claim 1 or 2, wherein a flexible element connects the carriage to a winding mechanism, the element being entrained around a series of pulleys mounted on said frame.

4. Cutting apparatus as claimed in Claim 3, wherein two pulleys are provided, one roller at the one end of the guides and one roller on the adjacent cross-member.

5. Cutting apparatus as claimed in Claim 4, wherein the anchoring mounting of the pulley on said cross-member is in longitudinal alignment with the anchoring mounting of the element to the carriage.

6. Cutting apparatus as claimed in any one of Claims 3,4 or 5, wherein intermediate of the length of the guide on which the roller is mounted, a reel of the winding mechanism is mounted and around which the element is adapted to be wound onto and off.

7. Cutting apparatus as claimed in Claim 6, wherein a handle is provided to enable the reel to be rotated to wind the element onto and off so to cause the carriage to be moved longitudinally of said guides.

8. Cutting apparatus as claimed in any one of the preceding Claims, wherein two disc blades are provided on the power shaft of the saw.

9. Cutting apparatus as claimed in Claim 8, wherein the distance between the two blades is adjustable.

10. Cutting apparatus as claimed in any one of the preceding Claims, wherein spray apparatus is provided including one or more spray nozzles connected by piping to a water supply, the nozzle or nozzles being directed onto the cutting operation.

11. Cutting apparatus as claimed in any one of the preceding Claims, wherein the frame securing means comprises a wheeled assembly mounted at the end of the frame remote from the pulleys and actuable to be extended to jam a frame against ceiling joists to secure the frame against a wall.

12. Cutting apparatus substantially as hereinbefore described with reference to the accompanying drawings.