GB2256613A

GB2256613A - Cutting machine

Info

Publication number: GB2256613A
Application number: GB9112641A
Authority: GB
Inventors: John Edwin Oakes
Original assignee: P B MACHINES Ltd
Current assignee: P B MACHINES Ltd
Priority date: 1991-06-12
Filing date: 1991-06-12
Publication date: 1992-12-16
Anticipated expiration: 2011-06-12
Also published as: GB9112641D0; GB2256613B

Abstract

The cutting machine (10) for sawing floors or the like consists of a wheeled chassis (12) having handle means (14) at the rear thereof, a sub-frame (22) pivotally mounted on the chassis (12) adapted to be lowered relatively thereto, and a power-driven cutting disc or saw (not shown) disposed in an upright plane rotatably mounted on the sub-frame (22) whose direction of rotation moves the lower portion of the disc or saw (not shown) towards the front of the chassis (12). The sub-frame (22) is pivotally connected to the chassis (12) and is lowered against the action of a counter balancing spring means (34) by a lowering mechanism (32) to adjust the depth of cut of the disc or saw (not shown). <IMAGE>

Description

Improvements in or relating to cutting machines." This invention relates to cutting machines and more particularly, but not exclusively, to improvements in or relating to mobile machines for sawing floors or the like.

Mobile cutting machines for sawing floors or the like formed of concrete asphalt or similar materials are already known.

Such known machines usually comprise a wheeled chassis having an abrasive cutting disk or saw mounted thereon in a vertical plane for rotation about a horizontal axis. The disk or saw is driven by power operated means such as an internal combustion engine mounted on the chassis and the saw or disk is capable of being lowered into engagement with the surface beneath the machine so that the disk or saw cuts a slot in the surface as the machined is wheeled therealong by an operative.

Such conventional mobile cutting machines suffer from a number of problems and disadvantages. One such problem from which most machines suffer is that the cutting disk or saw tends to direct the dust and swarf from the cutting operation rearwardly towards the operative.

Where the cutting disk or saw is powered by an internal combustion engine, it is normal for the air intake of the engine and the exhaust to also be at the rear of the machine which, not only subjects the operative to exhaust fumes, but also results in the dust created by the cutting operation being drawn into the engine reducing the useful life thereof.

Furthermore, in conventional machines it is usual for the cutting disk or saw guard to be movable together with the cutting disk or saw as the disk or saw is lowered.

This results in a large portion of the disc or saw being permanently exposed to enable a full depth of cut to be achieved which increases the amount of dust or swarf discharged from the disk or saw during the cutting operation.

Such known cutting machines also suffer from an instability problem particularly where the machine is powered with an internal combustion engine resulting in the machine having a relatively high centre of gravity.

The object of this invention is to provide a machine which alleviates one or more of the above disadvantages of conventional cutting machines.

According to this invention, a cutting machine for use in sawing floors or the like comprises a wheeled chassis having handle means at the rear thereof, a sub-frame pivotally mounted on the chassis adapted to be lowered relatively thereto, and a driven cutting disc or saw disposed in an upright plane rotatably mounted on the sub-frame, wherein the direction of rotation of the disk or saw moves the lower portion of the disk or saw towards the front of the chassis.

The rotation of the disc or saw in this direction not only discharges dust or swarf created by the cutting operation at the front of the machine away from an operative as the operative wheels the machine along the surface to be cut, but also avoids the dust or swarf being dragged through the cut from the front to the rear thereof thus improving the cutting action of the machine.

Preferably, also, a lowering mechanism is provided to lower the sub-frame relatively to the chassis to adjust the depth of cut in steps or increments.

The sub-frame is, preferably, pivotally connected to the chassis at the rear end thereof.

Preferably, the axis of the pivotal connection of the sub-frame to the chassis is co-axial with the axis of rotation of the rear wheels of the machine.

Preferably, also, power-operated means for driving the cutting disk or saw is mounted on the sub-frame.

Counter-balancing means is, preferably, provided for counter-balancing at least part of the weight of the sub-frame assembly to facilitate operation of the lowering mechanism.

Preferably, the counter-balancing means comprises spring means disposed between the sub-frame and the chassis.

Preferably, also, the rear wheels of the machine are disposed outside the plan outline of the chassis to provide optimum lateral stability of the machine.

The front wheel or wheels of the machine are, preferably, disposed at the front end of the chassis to optimise longitudinal stability of the machine.

Preferably, a guard adapted to enclose the cutting disk or saw is mounted on the chassis so that as the sub-frame is lowered by the lowering mechanism the lower portion of the disk or saw extends from the lower end of the guard.

Preferably, also, the guard is adapted to enclose the entire disk or saw therein when the disk or saw.is in the retracted position.

The disk or saw is, preferably, releasably connected and is capable of being removed and replaced with alternative diameters of disk or saw.

Preferably, where the power-operated means for driving the disk or saw is an internal combustion engine, the air inlet and/or the exhaust outlet are disposed at the front of the machine remote from the operative.

Preferably, also, the handle means is adapted to fold downwardly and the folded end thereof is releasably connected in the folded position to the chassis to facilitate transportation of the machine.

A cutting fluid reservoir is, preferably, provided on the machine together with supply means for supplying the cutting fluid to the disk or saw to facilitate the cutting operation and reduction of the dust created thereby.

Preferably, the chassis of the machine is substantially rectangular in plan view and the sub-frame is disposed within the central portion of the chassis.

Preferably, also, the chassis and/or the sub-frame are formed of an alloy of low density material to minimise the weight of the machine.

The cutting disk or saw is, preferably, disposed on one side of the machine in a plan which lies outside the plan outline of the outer portion of the chassis and/or the wheels of the machine on said one side thereof.

Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings of which Figure 1 is a diagrammatic side view of an internal combustion engine powered cutting machine; Figure 2 is a diagrammatic view of the opposite side of the cutting machine shown in Figurel; Figure 3 is a diagrammatic plan view of the cutting machine shown in Figure 1; Figure 4 is a diagrammatic side view of a compressed air powered cutting machine; Figure 5 is a diagrammatic view from the opposite side of the cutting machine shown in Figure 4; and Figure 6 is a diagrammatic plan view of the cutting machine shown in Figure 4.

Referring now to Figures 1 to 3 of the drawings, in one embodiment of the invention a cutting machine indicated generally at 10 for cutting a slot in or sawing a floor, road surface or the like comprises a wheeled chassis 12 which is substantially rectangular in plan view.

The chassis 12 is provided at the rear end with a handle assembly 14 by means of which an operative wheels the machine 10 along the surface to be cut. The handle assembly 14 is foldable rearwardly about a pivot point (not shown) so that the upper hand grip portion 16 is moved towards the chassis 12 and is releasably securable thereto to facilitate transportation of the machine 10.

The chassis 12 is substantially rectangular in plan view and is provided with two rear wheels 18 disposed outside the plan outline of the chassis 12 to optimise the lateral stability of the machine 10. Two laterally spaced-apart front wheels 20 are mounted on the chassis 12 at the front end thereof to provide optimum longitudinal stability.

A sub-frame 22 is disposed within the open central area of the chassis 12 and is pivotally connected thereto, the axis of pivotal connection being co-axial with the axis of rotation of the rear wheels 18. The positioning of the sub-frame 22 in this central area of the chassis 12 enables the sub-frame 22 to pivot downwardly relatively to the chassis 12.

An internal combustion engine 24 is mounted on the sub-frame 22 with air inlet 26 and exhaust disposed at the front of the machine remote from the operative. A rotatable boss 28 is drivably connected by a drive shaft and pulley and belt assembly 30 to the engine 24, the assembly 30 being located at the front of, the machine 10 to facilitate servicing and/or replacement of the drive belts. A cutting disk of abrasive material or a circular saw (not shown) is releasably connected to the boss 28 so as to be driven thereby to effect cutting of the surface over which the machine is wheeled by the operative.

The disk or saw is driven by the engine 24 via the drive assembly 30 in a direction whereby the lower portion of the disk or saw moves towards the front of the machine 10. The rotation of the disk or saw in this direction, not only discharges the dust and swarf created by the cutting operation away from the operative, but also avoids the dust and swarf being dragged through the cut from the front to the rear thereof as would be the case if the direction of rotation of the disk or saw was reversed, thus improving the efficiency of the cutting action of the machine 10.

A lowering mechanism 32 controlled by the operative is provided for lowering the sub-frame 22 relatively to the chassis 12 to adjust the depth of cut in steps or increments. A counter-balancing spring 34 is disposed between the sub-frame 22 and the chassis 12 to counter-balance at least part of the weight of the sub-frame 22, the engine 24 and other components associated therewith to facilitate operation of the lowering mechanism 32. A depth gauge 36 is provided to indicate to the operative the depth of cut being made by the machine 10 during the cutting operation.

The disk or saw mounted on the boss 28 is disposed in a vertical plane which lies outside the plan outline of the chassis 12 of the machine 10 to enable a cut to be made on one side of the machine 10 as the machine is wheeled along a surface. This is particularly useful when a rough edge of a surface is to be trimmed to provide a straight edge which is often necessary when preparing a road surface for resurfacing or edging with kerb stones.

A pointer 36 is mounted on the chassis 12 at the front of the machine 10 in line with the plane of the disk or saw to indicate to the operative the line of the cut being made during the cutting operation.

A guard 38 for enclosing the disk or saw is mounted on the chassis 12 so that as the sub-frame 22 is lowered by the lowering mechanism 32, the lower portion of the disk or saw extends from the lower end of the guard 38, The guard 38 fully encloses the entire disk or saw when the disk or saw is in the retracted position.

A reservoir 40 for cutting fluid such as water which assists cutting and inhibits the creation of dust is mounted on the machine and a supply pipe 42 directs the fluid onto the disk or saw.

The chassis 12 and sub-frame 22 are formed of an alloy of low density material to keep the weight of the machine 10 to a minimum to facilitate handling thereof.

Referring now to Figures 4 to 6 of the drawings1 in another embodiment of the invention a cutting machine indicated generally at 50 comprises a wheeled chassis 52 which is provided at the rear end with a handle assembly 54 by means of which an operative wheels the machine 50 along the surface to be cut.

The handle assembly 54 is foldable rearwardly about a pivot point (not shown) so that the upper hand grip portion 56 is moved towards the chassis 52 and is releasably securable thereto to facilitate transportation.

The chassis 52 is provided with two rear wheels 58 disposed outside the plan outline of the chassis 52 to optimise the lateral stability of the machine 50. A front wheel 60 is mounted on the chassis 12 at the front end thereof to provide optimum longitudinal stability.

A sub-frame 62 is pivotally connected to the chassis 52,the axis of pivotal connection being co-axial with the axis of rotation of the rear wheels 58. The sub-frame 22 pivots downwardly relatively to the chassis 52.

An air motor assembly 64 is mounted on the sub-frame 62 and a cutting disk of abrasive material or a circular saw (not shown) is driven thereby to effect cutting of the surface over which the machine is wheeled by the operative.

The disk or saw is driven.by the motor 64 in a direction whereby the lower portion of the disk or saw moves towards the front of the machine 50. The rotation of the disk or saw in this direction, not only discharges the dust and swarf created by the cutting operation away from the operative1 but also avoids the dust and swarf being dragged through the cut from the front to the rear thereof as would be the case if the direction of rotation of the disk or saw was reversed, thus improving the efficiency of the cutting action of the machine 50.

A lowering mechanism 66 controlled by the operative is provided for lowering the sub-frame 62 relatively to the chassis 52 to adjust the depth of cut in steps or increments. A depth gauge 68 is provided to indicate to the operative the depth of cut being made by the machine 50 during the cutting operation.

The disk or saw is disposed in a vertical plane which lies outside the plan outline of the chassis 52 of the machine 50 to enable a cut to be made on one side of the machine 10 as the machine is wheeled along a surface. A pointer 70 is mounted on the chassis 52 at the front of the machine 50 in line with the plane of the disk or saw to indicate to the operative the line of the cut being made during the cutting operation.

A guard 72 for enclosing the disk or saw is mounted on the chassis 52 so that as the sub-frame 62 is lowered by the lowering mechanism 66, the lower portion of the disk or saw extends from the lower end of the guard 72.

The guard 72 fully encloses the entire disk or saw when the disk or saw is in the retracted position.

A reservoir 74 for cutting fluid such as water which assists cutting and inhibits the creation of dust is mounted on the machine and a supply pipe 76 directs the fluid onto the disk or saw.

Although the above described cutting machines are particularly suitable for use in sawing floors or the like, they can be used for other purposes without departing form the scope of this invention.

Claims

What we claim is:

1. A cutting machine for use in sawing floors or the like comprising a wheeled chassis having handle means at the rear thereof1 a sub-frame pivotally mounted on the chassis adapted to be lowered relatively thereto, and a driven cutting disc or saw disposed in an upright plane rotatably mounted on the sub-frame, wherein the direction of rotation of the disc or saw moves the lower portion of the disc or saw towards the front of the chassis.

2. A cutting machine according to Claim 1, wherein a lowering mechanism is provided to lower the sub-frame relatively to the chassis to adjust the depth of cut in steps or increments.

3. A cutting machine according to Claim 2i wherein the sub-frame is pivotally connected to the chassis at the rear end thereof.

4. A cutting machine according to Claim 3, wherein the axis of the pivotal connection of the sub-frame to the chassis is co-axial with the axis of rotation of the rear wheels of the machine.

5. A cutting machine according to any one of the preceding claims, wherein power-operated means for driving the cutting disc or saw is mounted on the sub-frame.

6. A cutting machine according to any one of the preceding claims and Claim 2, wherein counter-balancing means is provided for counter-balancing at least part of the weight of the sub-frame assembly to facilitate operation of the lowering mechanism.

7. A cutting machine according to Claim 6, wherein the counter-balancing means comprises spring means disposed between the sub-frame and the chassis.

8. A cutting machine according to any one of the preceding claims, wherein the rear wheels of the machine are disposed outside the plan outline of the chassis to provide optimum lateral stability of the machine.

9. A cutting machine according to any one of the preceding claims, wherein the front wheel or wheels of the machine are disposed at the front end of the chassis to optimise longitudinal stability of the machine.

10. A cutting machine according to any one of the preceding claims and Claim 2, wherein a guard adapted to enclose the cutting disc or saw is mounted on the chassis so that as the sub-frame is lowered by the lowering mechanism, the lower portion of the disc or saw extends fron the lower end of the guard.

11. A cutting machine according to Claim 10, wherein the guard is adapted to enclose the entire disc or saw therein when the disc or saw is in the retracted position.

12. A cutting machine according to any one of the preceding claims, wherein the disc or saw is releasably connected to the machine so as to be capable of being removed and replaced with alternative diameters of disc or saw.

13. A cutting machine according to any one of the preceding claims and Claim 5, wherein where the power-operated means for driving the disc or saw is an internal combustion engine, the air inlet and/or the exhaust outlet are disposed at the front of the machine remote from the operative.

14. A cutting machine according to any one of the preceding claims, wherein the handle means is adapted to fold downwardly and the folded end thereof is releasably connected in the folded position to the chassis to facilitate transportation of the machine.

15. A cutting machine according to any one of the preceding claims, wherein a cutting fluid reservoir is provided on the machine together with supply means for supplying the cutting fluid to the disc or saw to facilitate the cutting operation and te reduction of the dust created thereby.

A A cutting machine according to any one of the preceding claims, wherein the chassis of the machine is substantially rectangular in plan view and the sub-frame is disposed within the central portion of the chassis.

17. A cutting machine according to any one of the preceding claims, wherein the chassis and/or the sub-frame are formed of an alloy of low density material to minimise the weight of the machine.

18. A cutting machine according to any one of the preceding claims, wherein the cutting disc or saw is disposed on one side of the machine in a plane which lies outside the plan outline of the outer portion of the chassis and the wheels of the machine on one side thereof.

19. A cutting machine constructed, arranged and adapted to operate substantially as herinbefore described with reference to, and as illustrated by, Figures 1 to 3 or Figures 4 to 6 of the accompanying drawings.