GB2377203A

GB2377203A - A guided power tool assembly

Info

Publication number: GB2377203A
Application number: GB0114992A
Authority: GB
Inventors: Brian Brunt
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-06-20
Filing date: 2001-06-20
Publication date: 2003-01-08
Also published as: WO2003000451A2; WO2003000451A3; GB0114992D0

Abstract

A guide assembly for power hand-tools, such as circular saws 2, has a track 3 securable by use of various clamps to a work piece. It has a carriage 4, slideably mounted on the track, and drive means 5 and 7 for propelling the carriage along the rack 10 attached to the track. The carriage comprises mounting means for removably mounting the tool, so that as the carriage moves along it guides the tool which in turn works on the workpiece. An accurate, straight and even cut along a large sheet of material can thus be achieved when the tool is a circular saw.

Description

A Guided Power Tool Assembly Field of the Invention This invention relates to the field of hand-held power tools, such as circular saws, routers and the like, and to assemblies that improve the accuracy and safety of their use.

Background of the Invention It is common practice for many stock materials such as M. D. F. (medium-densityfibreboard), Chipboard and Plywood to be supplied to the trade and public in large, difficult to handle sheets.

A number of tools are available to cut this stock material i. e. Hand Saws, Handheld power tools and Circular Table Saws. As it stands all of these tools have their own inherent problems. Hand Saws are labour intensive and require a high level of skill in their use; also further work may be required to finish the cut edge.

Hand-held power tools immediately present a danger to the operator and require a reasonable level of skill in order to achieve the desired result. These tools require a manual feed; and when the material is fed by hand the working will not be constant. One possible result could be an uneven cut, raising the need for further work to finish the cut edge.

Circular Table Saws are probably the best method available to the trade and the public but due to costs involved, portable circular table saws are the more affordable option. With portable table saws the stock material is normally fed through by hand which produces extreme danger for the operator. Another disadvantage is that when handling large sheets of stock material it is normally a two-man job to feed the sheets through the saw. Once again due to uneven feed rates further work may be necessary to finish the cut edge.

Summary of the Invention In response to the above problems the invention provides a power hand-tool and guide assembly comprising: a track securable to the work-piece; a carriage slideably mounted to the tracks; mounting means on the carriage removably mounting a power

hand tool for working the work-piece as the carriage slides along the track; and drive means for propelling the carriage along the track.

It will be understood from the invention that the term work-piece refers to an object, which is the subject of tooling by a power hand-tool, examples of which being stock material such as MDF, plywood and even sheet metal or structural objects such as walls and floors.

The track may be made from a light alloy so as to allow the assembly to be transported more easily.

In a preferred embodiment the track may have adjustable clamps, such as Gclamps, which can be adjusted to accommodate work pieces of different thickness. It may be of further benefit for the track to have a range of gradation points along its length, onto which the clamps can be arranged so that work-pieces of different lengths can be accommodated by the clamps.

Preferably the track will have an end limiting means to physically limit the movement of the carriage along the track beyond a certain point. It may be of further advantage-for safety amongst other things-if the end limiting means were to have a system cut off switch, so that when the carriage reaches the end of its journey along the track the system switches off causing both the tool and the driving means to stop.

It may be advantageous if the track were to have a start marker means, which provides a start point from which the carriage can only travel forwards down the track. However, it is appreciated that the gearing of the driving means may act to limit the movement of the carriage. Further benefit may be gained if the start marker means has a locking means, which can be engaged to hold the carriage at the start point; this may be of use when the invention is not in use or even during transport of the assembly.

Alternatively, it may be possible for the track to have release means, which allow the carriage to be completely removed for ease of transport.

It may also be of advantage for the driving means to be capable of returning the carriage back to the start of its run, with the start point possibly providing the means of stopping the returning carriage.

In order to reduce the friction between the track and the carriage as it travels along the track it may be preferable for the carriage to have inserts made from self- lubricating materials such as brass. The inserts could be arranged so as to provide the best lubrication to the movement of the carriage along the track.

Alternatively, the self-lubricating inserts could be arranged in the track itself thereby providing the necessary lubrication for the carriage movement along the track.

In the preferred embodiment the track comprises guiding rails, which are arranged to receive the carriage so that the movement of the carriage is restricted to a single plane as it travels along the track.

The drive means may be provided by a rack and pinion arrangement, wherein the rack runs along the length of the track and the pinion is mounted on the carriage.

Whereby the rotating of the pinion along the rack causes the carriage to travel along the track.

Alternatively the drive means may be provided by wheels, which run along a runway. It will be appreciated by the man skilled in the art that other arrangements of drive means may be used to transport the carriage along the track.

The drive means may be powered by its own motor, which may have a power pick-up from the power hand-tool. It is also appreciated that the motor may have its own power source. The motor may preferably have a reduction gearbox so that the pinion is caused to rotate at a speed, which is slow enough to give a suitable standard of tooling by the associated power tool.

It may be of further advantage if the drive means has a variable speed motor, to allow for tooling of different materials more conveniently.

It is also understood that the drive means may be powered directly by the power hand-tool itself. This could be achieved by a power hand-tool with an integrated gearbox that has a two output shafts. The first shaft, which would run at the tool motor's normal speed, would power the hand tool. The second shaft, which could be geared to run at a slower rate than the first shaft, would power the drive means.

In another preferred embodiment a power hand-tool guide will comprise: a track securable to the work-piece; a carriage slideably mounted to the tracks; mounting

means on the carriage to receive a power hand-tool for working the work piece as the carriage slides along the track; and drive means for propelling the carriage along the track.

With this embodiment, the mounting means on the carriage would be arranged to receive a variety of different power hand-tool types. This embodiment would therefore provide a more versatile system where tools could be interchanged as desired.

It will be appreciated by the man skilled in the art that most of the features already discussed with relation to the first preferred embodiment would be equally bene- ficial to this embodiment. One exception may be the use of the power tool to power the drive means, but as discussed above the drive means may be powered by its own motor.

It will be understood from the invention that in practice the work-piece would preferably be secured to a workable and then the assembly would be clamped onto the work-piece in order to achieve the best results. Although this is a preferred method of using the disclosed invention, it is appreciated that work-pieces may not require securing to a workable in order to use the invention.

Brief Description of the Drawings The invention will now be described with reference to the accompanying drawings in which: Figure 1 is a side view of a preferred embodiment of the invention; Figure 2 is a plan view of the preferred embodiment illustrated in Fig. 1; Figure 3 is an enlarged side view of the power tool section of the preferred embodiment illustrated in Figs. 1 and 2; Figure 4 is an enlarged end view of the power tool section of the preferred embodiment illustrated in Figs. 1 and 2.

Detailed Description of the Illustrated Embodiments Figure 1 shows the side view of a preferred embodiment of the Guided power tool assembly 1. A power tool 2 is mounted on a carriage 4, by fixings such as bolts, rivets or even by welding. The carriage 4 is in turn mounted on the track 3. Although

the power tool shown is circular saw it will be understood from the invention that other tools such as jig saws, power planers, routers and the like may be used.

The object, which is to be worked on by the power tool, shall be referred to as the work-piece for the sake of clarity. The work-piece (not shown) is held in position by the adjustable clamps 6 which are attached to the track 3 at receiving points 9.

Also attached to the carriage, by bolts, rivets or the like, are a pinion 5 and a motor 7 to drive it. As the power tool tools the work-piece, the pinion 5 is rotated by the associated motor 7. The rotating pinion 5 interacts with the rack 10, which is attached under tension along the length of the track 3, causing the carriage 4 and thus the tool to travel along the track at a uniform speed giving an even tooling to the workpiece.

Figure 2 shows a plan view of the preferred embodiment, with the rack 10 and pinion 5 arrangement illustrated more clearly. It is appreciated that other methods of driving the carriage along the track as possible including amongst other things, the use of rubber wheels and a runway.

In order for different sized work-pieces to be tooled the adjustable clamps 6 can be attached to the track 3 at any of a range of receiving points 9 along the length of the track 3, as dictated by the length of the work-piece being tooled. The adjustable clamps 6 comprise fixing means, which can be engaged with any particular receiving point 9 to hold the clamp to the track at a set position, and clamping means, which can be adjusted to clamp the work piece in position. Preferably the clamping means could be screw-adjustable, but it is appreciated that other methods of adjusting the clamp are possible.

The movement of the carriage 4 along the track 3 is directed and restricted by the guide rails 8. The guide rails are securely mounted, in parallel to one another, along the track by an appropriate fixing means, such as bolts, rivets or welding. It is appreciated that other types of fixing means may be suitable. The arrangement of the track 3 with the guide rails 8 creates two channels along which the carriage 4 moves. The resistance to the movement of the carriage 4 along the track 3 may be reduced by the use of inserts (not shown) made of self-lubricating materials such as brass or the like.

In the preferred embodiment shown the tool possesses a cut off switch (not shown), which will be activated by a limit switch when the tool reaches the end of its run. For convenience the limit switch may preferably be mounted in association with one of the adjustable clamps 6.

Figures 3 and 4 show enlarged views of the power tool mounted on the track, from which the interactions of the carriage and guide rails can be more clearly seen.

Claims

Claims 1. A guide assembly for a power hand-tool, the assembly comprising: a track securable to a work-piece; a carriage, slideably mounted to the track; mounting means on the carriage for removably mounting a power hand-tool for working the work-piece as the carriage slides along the track; and drive means for propelling the carriage along the track.
2. An assembly in accordance with claim 1, wherein the track comprises adjustable clamps for securing the track to work-pieces of different thicknesses.
3. An assembly in accordance with claim 1, wherein the track comprises a range of gradation points along its length onto which the clamps can be arranged such that the clamps can accommodate work-pieces of different lengths
4. An assembly in accordance with any preceding claim, wherein the track com- prises end limiting means to limit the movement of the carriage along the track.
5. An assembly in accordance with claim 4, wherein the end limiting means com- prises a cut off switch arranged to switch off the tool and the drive means when the carriage reaches the end limiting means.
6. An assembly in accordance with any preceding claim, wherein the track com- prises a start marker means, which provides a start point from which the car- riage can only travel forward along the track.
7. An assembly in accordance with claim 6, wherein the start marker means com- prises locking means arranged to hold the carriage at the start point.
8. An assembly in accordance with any preceding claim wherein the drive means comprises gearing arranged to limit movement of the carriage.
9. An assembly in accordance with any preceding claim wherein the track com- prises release means, which allows the carriage to be removed from the track.
10. An assembly in accordance with any preceding claim, wherein the drive means is arranged to return the carriage back to a start position after its run along the track.

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11. An assembly in accordance with claim 10, as dependent on claim 6 or claim 7, wherein the start marker means provides means for stopping the returning car- riage.
12. An assembly in accordance with any preceding claim wherein the carriage com- prises inserts formed from self-lubricating material to lubricate the movement of the carriage along the track.
1 3. An assembly in accordance with any preceding claim wherein the track com- prises self-lubricating inserts.
14. An assembly in accordance with claim 12 or claim 13 wherein the self-lubri- cating inserts are brass.
15. An assembly in accordance with any preceding claim wherein the track com- prises guide rails arranged to receive the carriage so as to restrict movement of the carriage to a single plane as it travels along the track.
1 6. An assembly in accordance with any preceding claim wherein the drive means comprises a rack and pinion, the rack running along the length of the track and the pinion being mounted on the carriage.
17. An assembly in accordance with any one of claims 1 to 15 wherein the drive means comprises wheels which run along a runway.
18. An assembly in accordance with any preceding claim wherein the drive means comprises a drive motor.
19. An assembly in accordance with claim 18 wherein the drive motor has a power pick-up from the power-tool.
20. An assembly in accordance with claim 18 wherein the drive motor has its own power source.
21. An assembly in accordance with any one of claims 18 to 20 wherein the drive motor comprises a reduction gearbox.
22. An assembly in accordance with any one of claims 18 to 21 wherein the drive motor is a variable speed motor.
23. An assembly in accordance with any preceding claim wherein the drive means is arranged to be powered by the power hand-tool.

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24. An assembly in accordance with any preceding claim, wherein the mounting means is adapted to mount a variety of power hand-tools.
25. An assembly in accordance with any preceding claim, wherein the mounting means is adapted to mount at least one power hand-tool from a list comprising: circular saws; jig saws; power planers ; and routers.
26. A power hand-tool and guide assembly comprising a guide assembly in accor- dance with any preceding claim, and a power hand-tool mounted on the car- riage.
27. An assembly in accordance with claim 26 wherein the power hand-tool is from a list comprising: circular saws; jig saws; power planers ; and routers.
28. A guide assembly substantially as hereinbefore described with reference to and/or as shown in the accompanying drawings.
29. A power hand-tool and guide assembly substantially as hereinbefore described with reference to and/or as shown in the accompanying drawings.