GB2453398A

GB2453398A - Handsaw with illumination means

Info

Publication number: GB2453398A
Application number: GB0804353A
Authority: GB
Inventors: Gordon Mcwilliam
Original assignee: Neill Tools Ltd
Current assignee: Neill Tools Ltd
Priority date: 2007-10-03
Filing date: 2008-03-07
Publication date: 2009-04-08
Also published as: GB0804353D0; WO2009044089A1; GB0719262D0; WO2009044091A1

Abstract

A handsaw 10 comprises a handle 14, a planar saw blade 12 and an indication means which is arranged, in use, to indicate a cutting plane of a cut or partial cut provided by the handsaw. The indication means comprises an illumination means 18 to provide an illuminated indicator of the cutting plane which is projected on to a surface of a material to be cut. The indication means also comprises an actuation means 24, which is arranged to selectively actuate the illumination means. The actuation means comprises a push to make non-locking mechanism. An actuating force has to be applied to the actuating means in order to operate the illumination means. Preferably, the actuating force is coincident with the plane of the saw blade. The handsaw may be used for cutting wood.

Description

HANDSAW

Field of the Invention

The present invention relates to handsaws and, specifically, to woodcut handsaws. More particularly, the present invention relates to providing indication means to indicate the direction and/or plane of the cutting direction or plane of a handsaw and/or woodcut handsaw and to providing a method of indicating the cutting direction or plane of a handsaw and/or woodcut handsaw.

Backaround to the Invention

Once a woodcut handsaw has commenced a cut within a material (for example, a workpiece) it can be difficult to change the direction of a cut due to the resistance to movement and restraint of the saw blade within the existing cut.

Accordingly, it is important to commence the cut with a woodcut handsaw at the correct angle and in the correct plane.

A cut with a woodcut handsaw is generally commenced by creating a small incision or nick on an edge of the material. Generally, the commencement edge is located spaced from the user. The saw blade edge is laterally retained within the cut such that the saw blade cannot move out of the initial incision or nick.

The hand saw then needs to be orientated such that the subsequent cuts will be in the correct direction and plane and in the required direction and plane. This is of particular importance at the start of a relatively long cut since such a small initial error will gradually increase in magnitude the further the cut is further away from the initial misdirected cut. For example, the initial error is an angular error and the distance (displacement) that the cut is from the required cut will increase as the distance from the incorrect starting incision increases.

At present, workmen may draw a line (e.g a guideline) on the surface of the material and attempt to follow the line using skill and judgement. It is a relatively skilled action to achieve an accurate cut. Such an accurate cut may be important Pl882spec as filed and critical in certain circumstances. If an incorrect cut is achieved or performed then the material may be wasted and this increases both the time and expense of the work.

In some circumstances, it may not be possible to draw a guide line on the surface of the material, for example, the surface may have an irregular shape (e.g. as with cornices, coving etc), the surface may be decorative or the surface may be otherwise unsuitable for a guide line to be drawn on the surface. In these situations, a workman may mark a beginning point and an end point and then attempt to imagine the line between these points in order to attempt to visualise the position of the guideline. This is difficult and frequently leads to inaccurate cuts.

Furthermore, guide markings on the surface of the material may become is visually obscured as the cut progresses due to the debris and contaminants created by the cut (e.g. sawdust). In addition, if the surface is tacky or is in the presence of moisture, then the debris (e.g. sawdust) may adhere to the material and it is not possible to simply blow the debris away in order for the guideline to be visible. Similarly, when cutting wood, resin may be present and this may adhere any contaminants (e.g. sawdust) which will obscure the visibility of the guideline.

The alignment of a saw when cutting non-perpendicularly along a material or work piece can be more difficult due to the ergonomics of the position of the user and/or the hand saw. In addition, when following guidelines there may be a tendency for the user to hold the saw such that the saw is towards a vertical position rather than in a substantially horizontal position and this can make the sawing action difficult and uncomfortable for a user.

Power saws and other power tools are frequently used. However, such power tools may be static and may require the workpiece to be moved to the location of the power tool rather than moving the tool to the workpiece. This can P1882.spec as filed be inconvenient and impossible in some circumstances. Accordingly, manually powered tools, for example handsaws are still required and are necessary as a result of the variety of situations and circumstances in which they can be used. In addition, hand tools are not limited by the provision of a power source.

Furthermore, power tools can be expensive.

It is an aim of the present invention to overcome at least one problem associated with the prior art whether referred to herein or otherwise.

]. 0 Summary of the Invention

According to a first aspect of the present invention there is provided a handsaw comprising indication means which is arranged, in use, to indicate the cutting plane of the handsaw wherein the indication means comprises illumination means providing an illuminated indicator of the cutting plane which is projected on to a surface of a material to be cut in which the indication means comprises actuation means which is arranged to selectively actuate the illumination means and wherein the actuation means comprises a push to make non-locking mechanism.

Preferably actuation means require an actuating force in order to operate the indication means in which the required actuating force is aligned with the direction of the plane of the blade of the handsaw and/or the cut or partial cut.

Preferably the handsaw comprises a woodcut handsaw.

Preferably the handsaw comprises a planar saw blade.

Preferably the actuation means comprises a single pole, single throw momentary (ON) -OFF switch.

The actuation means may comprise a non-latching and/or a non-locking switch.

P1882.spec as filed Preferably the handsaw comprises a handle.

Preferably the indicating means is integral within a handle of the handsaw.

Preferably the actuation member requires an actuating action which urges, in use, the saw blade into a cut.

Preferably the actuation member requires an actuating force wherein the direction of the required actuating force is coincident with the plane of the planar saw blade.

Preferably the actuation member requires a push force which also urges the saw blade into a plane of the cut.

Preferably, the force required to actuate the actuation member may urge or force the plane of the saw blade to align and coincide with the plane of the cut.

The handsaw may comprise adjustment means to adjust a lateral position of the illuminated indicator (on a surface of a work piece) relative to the plane of the planar saw blade.

Preferably the adjustment means enables the illumination means to be rotated about a single axis.

Preferably the illumination means is secured integrally in the handle of the handsaw.

Preferably the handle comprises retaining means to retain a light emitting unit of the illumination means with the handle and fixes the position of the light-emitting unit in the handle. Preferably the light emitting unit comprises a cylindrical housing and the handle may define a cylindrical space to retain the P1882.spec as liled light emitting unit in the handle. Preferably the retaining means prevents translational movement of the light emitting unit relative to the handle and/or the planar saw blade.

Preferably the light emitting unit is rotatable about a single central (longitudinal) axis.

Preferably the handsaw comprises adjustment means to adjust the rotational position (or orientation) of the light emitting unit in the retaining means.

Preferably the adjustment means comprises a single adjuster.

Preferably the handle comprises securement means to secure the saw blade to the handle. Preferably the securement means and the retaining means are integral with the handle such that the relative translational positions of the saw blade and the light emitting unit are fixed.

Preferably the indication means provides an illuminated indicator of the plane of the saw blade and, in particular, illuminates the part of the material which lies in the plane of the saw blade and more preferably illuminates the part of the material which lies in a plane coincident with the plane of the saw blade and is also directly exposed to light from the illumination means.

Preferably the handsaw comprises a handle and a planar saw blade.

Preferably the material comprises a workpiece.

Preferably the illumination means comprises a lighting unit (or light emitting unit) comprising a light source and a lens system.

Preferably the light source is a laser light source.

P1882.spec as filed The light source may comprise a light emitting diode.

The light source may compnse a laser diode.

Preferably the lens system is arranged to produce a planar light beam.

The lens system may comprise a Fresnel lens.

The lens system may comprise a stepped lens.

The lens system may comprise a collimator.

The lens system may comprise a focusing lens.

Preferably the illuminated indicator comprises a linear illuminated indicator.

Preferably the planar light beam is arranged to be coincident with the plane of the saw blade.

Preferably the illumination means and, in particular, preferably the lighting unit is permanently and/or fixably mounted to the handle.

Preferably the illumination means (and, in particular, preferably the lighting unit) is not moveable relative to the handsaw and/or saw blade and/or the handle.

Accordingly, once mounted, the plane of the light beam projected from the lighting unit may not need to be adjusted relative to the plane of the saw blade.

Preferably the illumination means is arranged to project a planar light beam from a heel of the handsaw towards a toe of the handsaw.

Preferably the illumination means is arranged to project a substantially divergent planar light beam. Preferably the divergent light beam extends in a P1882.spec as filed plane between a first direction and a second direction. Preferably the first direction is substantially parallel to a direction of a cutting edge of the saw blade.

Preferably the first direction is substantially parallel to, but spaced from, a direction of a cutting edge of the saw blade.

The illumination means may be arranged to project a divergent planar light beam having an angle of divergence greater than 22.5° and preferably having an angle of divergence greater than 45° and more preferably having an angle of divergence of substantially 600.

Preferably the illumination means may be arranged to direct a planar divergent light beam having an angle of divergence of less than 900 and more preferably less than 800.

Preferably the saw blade is flexible.

Preferably the saw comprises a planar saw blade.

Preferably the illumination means is arranged to provide an illuminated line on a surface of a material to be cut. The width of the line maybe less than 5 mm and preferably the width of the illuminated line is less than 3 mm and more preferably the width of the illuminated line is substantially 1 mm.

Preferably the width of the line is set (or fixed) and is not adjustable. The width of the line may be determined by a lens in the lens system.

Preferably the illumination means is arranged to provide a colored line on a surface of a material to be cut.

The actuating means may comprise an actuating member. The actuating member may comprise a trigger and preferably comprises a digit (finger or thumb) operated trigger or button. The actuating member may comprise a button P1882.spec as filed and preferably comprises a push button. The push button may be arranged, in use, to be activated by a digit (e.g. a thumb or finger) of the user. The actuating member may be mounted on an upper surface of the handle of the handsaw.

Preferably the actuation means comprises bias means which is arranged to bias the actuating member in a non-operative position. Preferably the bias means comprises urging means to urge the actuating member towards a non-operative position. Preferably the actuating member is arranged to be manually moved from a non-operative position (in which power is not supplied to the light source) io to an operative position (in which power is supplied to the light source).

Preferably the actuating member is arranged to move from an operative position to a non-operative position by bias means.

Preferably the indication means comprises power means. Preferably the power means is arranged to supply power to the illumination means. The power means may be located in the handle of the handsaw. The power means may comprise a battery or a plurality of batteries.

According to a second aspect of the present invention there is provided a method of indicating the cutting plane of a handsaw comprising operating illuminating means of the hand saw in order to project an illuminated indicator of the cutting plane on to a surface of a material to be cut wherein the method comprises pushing actuation means which is arranged to selectively actuate the illuminating means and wherein the actuation means comprises a push to make non-locking mechanism.

The method may comprise indicating a non-perpendicular cut on the material.

The method may comprise providing an illuminated line indicating the cutting line on the material of the saw.

P1882.spec as filed The method may comprise providing an illuminated indicator on a first surface and a second surface of a material to be cut. The first surface may be substantially perpendicular to the second surface.

The method may comprise pushing an actuating member in order to provide the illuminated indicator.

The method may comprise providing bias means in order to urge the actuating member from an operative position to a non-operative position.

The method may comprise substantially releasing the handsaw whilst operating the actuating member.

Brief Description of the Drawings

For a better understanding of the invention and to show how the same may be carried into effect, there will now be described by way of example only, specific embodiments, methods and processes according to the present invention with reference to the accompanying drawings in which: Figure 1 is a side view of a preferred embodiment of a hand saw.

Figure 2 is a perspective view of part of a workpiece including a cutting guideline.

Figure 3 is a perspective view of part of a preferred embodiment of a handsaw in which the illuminated indicator demonstrates that the handsaw is not correctly aligned.

Figure 4 is a perspective view of a part of a preferred embodiment of a handsaw in which the illuminated indicator demonstrates that the handsaw is correctly aligned.

P1882.spec as filed Figure 5 is a perspective view of a part of a preferred embodiment of a hand saw approximately mid-way through a cut in which the illuminated indicator demonstrates that the hand saw is not correctly aligned.

Figure 6 is a perspective schematic view of a example of a cutting plane in a workpiece.

Figure 7 is a perspective schematic view of another example of a cutting plane in a workpiece.

Figure 8 is a perspective view of a part of a handle of a preferred embodiment of a woodcut handsaw.

Figure 9 is a perspective view of a part of a preferred embodiment of a woodcut handsaw.

Figure 10 in a perspective cut-away view of a part of a handle of a preferred embodiment of a woodcut handsaw.

Description of the Preferred Embodiments

There will now be described by way of example only a specific mode contemplated by the inventors. In the following description numerous specific details are set forth in order to provide a thorough understanding. It will be apparent however, to one skilled in the art, that the present invention may be practiced without limitation to these specific details. In other instances, well known methods and structures have not been described in detail so as not to

unnecessarily obscure the description.

As shown in figure 1, a woodcut handsaw 10 comprises a planar saw blade 12 and a handle 14. The saw blade 12 extends in a single plane from an upper edge 15 to a lower cutting edge 16. The cutting edge 16 comprises a series of P1882.spec as filed cutting teeth. The saw blade is for use in cutting straight lines and is not operable whilst the saw blade is flexed.

The saw blade 12 comprises a metal and is flexible laterally albeit significant flexion of the saw blade it would prevent the handsaw from being used efficiently.

Accordingly, this contrasts with hacksaws, coping saws and the like in which the blade can be flexed significantly and still used effectively. The present invention is primarily concerned with cutting straight lines and the saw blade maintains its mechanical integrity and avoids angular tension and angular flexion. The saw blade 12 extends from a heel 20 to a toe 22 in a longitudinal direction and the saw blade 12 has two planar faces.

The woodcut handsaw 10 includes illumination means 18 in the handle 14 thereof. The illumination means 18 comprise a lighting unit (or light emitting unit) including a light source and a lens system. The light source comprises a laser which is arranged to produce a single beam. The lens system is arranged to produce a planar light beam which is emitted from the heel 20 of the saw 10 to the toe 22.

The lens system may include a Fresnel lens, stepped lens, collimator or other suitable lens to produce the planar beam. In the preferred embodiment, the lens system includes a focusing lens which focuses the light from the light source on to a stepped lens which then produces a planar light beam. The focusing lens is arranged to produce a point light source which is the converted into a planar light beam by the stepped (or other suitable) lens.

The planar light beam is divergent. The angle of divergence, 0, may be substantially 45° to 60° such that the full angle of the illumination of the planar light beam is between 90° and 120°. However, further suitable angles of divergence can be used in order to generate suitable lengths of linear illuminator indicator.

P1882spec as filed The illumination means includes actuating means comprising an actuating member 24. The actuating member 24 comprises biasing means to urge the actuating member 24 from an operative position to a non-operative position.

Accordingly, the illumination means 18 is normally in a default position such that no illumination is provided. When a user pushes the actuating member 24 then the illumination means provides an illuminated linear light on the material to be cut where the cutting plane of the saw blade is coincident with the surface of the material to be cut.

In particular, the actuating member comprises a push to make non-locking mechanism such that an actuating force has to be applied to the actuating member 24 in order to operate the illumination means 18 and the illumination means 18 automatically ceases operating once the force is released.

Accordingly, the illumination means 18 only operates whilst the user applies the required actuating force. This means that the illumination means 18 is not operated whilst the saw is cutting. This is particularly advantageous because a permanently indicating light could provide a significant distraction and may also cause a hazard in some circumstances. In addition, the present invention minimises the power required. Specifically, the present invention by not continually supplying power to the light emitting unit results in the life of the batteries being approximately the same as the life of the cutting edge of the blade of the saw or at least of the same order. Accordingly, the mechanisms of the present invention are not disturbed by continually requiring replacement batteries which may weaken the handsaw. Furthermore, since the electrical components are not powered during use, the present invention and the components thereof are less likely to be damaged.

The direction of the force required to push the actuating member 24 is arranged to be in the same direction as the plane of the saw blade 12.

Accordingly, in use, the action of pushing the actuating member 24 forces the saw blade 12 into the cut and this therefore provides a better indication of the cutting plane. For example, if the force required was offset then the force would P1882.spec as flied urge the handsaw 10 and, in particular, the illuminated indicator out of alignment with the cutting plane. For example, a laterally mounted actuating switch or button would encourage the saw to rotate within the cut and to indicate the inaccurate cutting plane.

The woodcut handsaw 10 includes power means including a power supply in order to provide power to the light source. In particular, the power supply may comprise one or more batteries.

The light emitting unit 18 is permanently and fixably mounted in the handle 14 such that the planar light beam is coincident with the plane of saw blade 12.

The light emitting unit 18 is arranged to be mounted and calibrated during manufacture such that the subsequent user does not have to align the light source. In addition, the fixed mounting prevents or inhibits the light emitting unit 18 from moving relative to the plane of the saw blade 12 during use.

In the preferred embodiment, the light emitting unit 18 is secured and retained in the handle 14 of the woodcut handsaw 10 such that the central plane of the light emitting unit 18 is coincident with the plane of the planar saw blade 12. The tight emitting unit 18 is adjustable and specifically is rotatable about a single central axis. The light emitting unit 18 comprises a cylindrical housing 54 and this enables the light emitting unit 18 to be secured and retained in the handle 14 of the woodcut handsaw 10 such that the light emitting unit 18 is restrained in all three translational planes but is rotatable about the central longitudinal axis.

As shown in figure 8, 9 and 10 the handle 14 comprises a plastics and includes a first lateral member 50 and a second lateral member 52 which are arranged, in use, to be secured together in order to form a substantially hollow handle 14. Each lateral member 50, 52 comprises a moulded plastic member, for example injection moulded members. The two lateral members 50, 52 provide a substantially sealed chamber which thereby protects the mechanisms in the P1882.spec as filed present invention for dust, debris, moisture etc. The two lateral members 50, 52 provide retaining means in order to retain the light-emitting unit 18 within the handle 14 such that the light emitting unit 18 is integral with the handle 14.

The retaining means provides a chamber or cavity in which the light emitting unit 18 is retained. In particular, the two lateral members 50, 52 comprise a number of retaining members 60, 61, 62, 63, 64, 65 or fins to retain the light emitting unit 18 therein in order to prevent relative translational movement between the light emitting unit 18 and the handle 14. The retaining members 60, 61, 62, 63,64, 65 are arranged to project across the inside chamber of the hollow handle 14 and effectively define a retaining space in the handle 14.

The light emitting unit 18 comprises a housing 54 which is cylindrical. The housing 54 may comprise a brass housing. The housing 54 is arranged to simply locate within the retaining space defined by the retaining members 60, 61, 62, 63, 64, 65 in order to prevent translational movement between the housing 54 and the handle 18. The housing 54 simply locate using a push fit operation.

The handsaw 10 comprises adjusting means in order to adjust the lateral plane of the illuminated line on the work piece relative to the saw blade 12. The adjustment means enables a user to accurately calibrate the laser guided handsaw and, in particular, enable the user to move the illuminated line 40 into the correct position, for example, the illuminated line 40 may become offset through use of the handsaw since handsaws are subject to significant vibrations and impacts during the use. The adjustment means only provides adjustment about a single rotational axis and the planar light beam is not adjustable in a translational plane or in the other two rotational axis. This thereby reduces the opportunities for the illuminated line becoming offset whilst still enabling a user to make slight adjustments.

The cylindrical housing 54 is rotatable about a single longitudinal axis which lies centrally along the cylindrical housing 54. As shown in figure 8, figure 9 and P1882.spec as 1Ied figure 10, the retaining means prevents any other movement of the cylindrical housing 54 relative to the handle 14. Since the planar saw blade is also similarly fixed and secured to the handle 14 (and to the lateral members 50, 52, of the handle 14) the relative positions of the planar saw blade and the light emitting unit 18 are fixed by the construction of the handsaw 10 and the only factor which is able to create an inaccurate indicator can be adjusted (i.e. the relative rotation about a central axis of the cylindrical light emitting unit 18).

The housing 54 has a radially projecting surface 68 which projects radially outwardly from the cylindrical housing 54. The adjustment means comprises a single adjuster 70 located in a cylindrical chamber 71. In particular, the adjuster comprises a grub screw 70 having an engagement head which can be engaged by a screw driver, allen key etc and has an abutment end which abuts against the radially projecting surface 68. The adjustment means also comprises resilient means which is arranged to urge (or bias) against the opposite side of the radically projecting surface and to counteract the abutment of the adjuster. In particular, the resilient means comprises a spring 72 located in a cylindrical chamber 73 which opposes the force of the grub screw 70 and thereby stabilizes the rotational position of the cylindrical light emitting unit 54. As the grub screw 70 is screwed or rotated into or out of the cylindrical chamber 71, the force of the grub screw 70 which is angularly offset from the central longitudinal axis of the light emitting unit 54 causes the light emitting unit 54 to rotate and thereby adjusts the plane of the planar light emitted from the light emitting unit 18. However, the fixed translational position of the light emitting unit 18 always ensures that the plane of the planar light beam is always coincident with the plane of the cutting plane of the saw blade at a position just below the edge of the cutting edge of the saw blade.

In the preferred embodiment, the adjustment means enables less than 10 degrees of rotational movement of the planar light beam and preferably allows approximately 4 degrees of rotational movement and specifically +1-2 degrees of the central plane.

P1882.spec as filed The planar light beam extends between a first direction 26 and a second direction 28. The first direction 26 is arranged to be substantially parallel to the cutting edge 16 of the saw blade 12. In addition, the first direction 26 is spaced slightly from the cutting edge 16 of the saw blade 12. As shown in figure 1, the second direction 28 extends rearwardly relative to the hand saw although this is dependent upon the angle of divergence of the planar light beam.

In use, the user initially creates a small cut or incision or nick 34 in an edge 32 of a workpiece 30, as shown in figure 2. The workpiece 30 has a guideline 36 which is manually drawn onto the surface or the surfaces 35, 37 of the workpiece by the user. Normally, a user would then simply a ttempt to manually move the plane of the saw blade in order to try progress the cut along the guideline 36.

However, as previously discussed, it can be difficult to obtain and maintain an accurate cut.

In the present invention, the cutting edge 16 of the saw blade 12 is inserted into the initial cut 34 such that the saw blade 16 is retained laterally relative to the workpiece 30. As shown in figure 3, the user then operates the actuating member 24 to provide an illuminated line 40 which indicates the location of the cut that would be achieved from that particular orientation of the saw blade 12.

The actuation member 24 requires a force to actuate the illumination means such that the direction of the required force is coincident with the plane of the saw blade 12 and thereby pushes the saw blade 12 into the cut and stabilizes the saw blade 12 to provide a more accurate representation of the cutting angle. The handsaw 10 can then be manually moved to the correct position such that the illuminated indicator line 40 is coincident with the guideline 36, as shown in figure 4. The user can then release the actuating member 24 and commence sawing.

Since the user is confident that the correct orientation of the saw 10 has been achieved, the user is able to initially be relatively aggressive in the sawing action.

P1882.spec as filed The user can then check the progress of the cut by simply stopping the sawing action and operating the actuating member 24 to provide an illuminated line, as shown in figure 5. At this position, it is important and beneficial that the user does not manually flex the saw blade 12 within the cut since this would provide inaccurate feedback of the orientation plane of the saw blade 12 of the position of the intended cut. The configuration of the actuation member 24 ensures that the user does not manually flex the saw blade 12 since the required actuating force is in the same place as the cut and/or the plane of the saw blade 12.

The user can continue to illuminate and monitor the cut as the cut progresses and the user can take any action that may be required to realign the actual cut with the required position of cut.

As shown in figures 3 to 5, the illuminated indicator line is provided on at least two surfaces 35, 37 of the work piece 30 and, in particular, the illuminated line 40 is displayed on an upper surface 35 and a facing surface 37 of the workpiece 30. This extended illuminate line 40 is provided due to the angle of divergence of the planar light beam.

Since the illuminated line 40 is provided on a facing surface 37 of the workpiece 30, the angle (q) of the cutting edge 16 of the saw blade 12 can be kept relatively shallow in order to provide a better cutting position. This shallow angle p provides a more ergonomically beneficial position for the user and enables the user to use the larger appropriate muscles of the upper trunk rather than the lower arm.

Whilst the preferred embodiment has been described above in relation to a perpendicular cut on a rectangular workpiece 30, the present invention is particularly useful in aligning a hand saw for irregular cuts and, in particular, cuts which do not have any perpendicular angles to the surface of the work, for example as shown in figure 6. In this example, the plane of the cut is at a lateral P1882.spec as filed angle a to the workpiece 30 and a vertical angle 13. In this example, neither the angle a to the upper surface 35 or angle 13 to the facing surface 35 are perpendicular.

In some circumstances, it is sometimes required to cut a relatively planar slice 30 from an end of the workpiece 30 as shown in figure 7. This can be particularly difficult since when the saw blade 12 starts drifting from the guideline it can be difficult to re-align the saw blade. In particular, a part of the planar slice may fracture the workpiece 30 whilst attempting to realign the saw blade 12.

Accordingly, the present invention provides a particular benefit in this situation.

The present invention improves on prior art handsaws in particular due to the required actuating force being aligned with the plane of the saw blade and the plane of the cut which prevents inaccurate indicators.

The present invention relates to a woodcut handsaw which is generally for use in cutting planar cuts or straight cuts and illuminated indicators for use of hacksaws, copying saws etc (for curved or shaped cuts) are particularly at risk of displaying inaccurate indicators due to the flexibility of the blades in the cut. It can be seen that a hacksaw or the like could be twisted in the cut to display any cuthng plane which would be different from the actual cuthng plane in practice.

Once such a blade has started a cut (particularly a deep cut) the twisting of the handle will not significantly affect the actual cutting plane. Accordingly, the present invention relates to woodcut handsaws.

The present invention is particularly beneficial over the prior art since the light emitting unit 18 is integral with the handle and does not require mounting fixtures to mount the light emitting unit 18 to the saw. Such mounting fixtures generally fail or loosen with use since the handsaw is exposed to repetitive vibrations and impacts. This results in illuminated indicators providing inaccurate indications of the cutting plane.

P1882.spec as filed

Claims

Claims 1. A handsaw comprising a handle, a planar saw blade and an indication means is arranged, in use, to indicate a cutting plane of a cut or partial cut provided by the handsaw wherein: the indication means comprises an illumination means providing an illuminated indicator of the cutting plane which is projected on to a surface of a material to be cut; in which; the indication means comprises an actuation means which is arranged to selectively actuate the illumination means; and wherein; the actuation means comprises a push to make non-locking mechanism.
2. A handsaw as claimed in claim 1, wherein the actuation means requires an actuating force in order to operate the indication means; in which the required actuating force is aligned with the direction of the plane of the blade of the handsaw and/or the cut or partial cut.
3. A handsaw as claimed in claim I or claim 2 wherein the handsaw comprises a woodcut handsaw.
4. A handsaw as claimed in any of claims I to 3 wherein the indication means is integral within the handle of the handsaw.
5. A handsaw as claimed in any of claims I to 4 wherein the actuation member requires an actuating force coincident with the plane of the planar saw blade.
6. A handsaw as claimed in any of claims I to 5 wherein the actuation member requires a push force to urge the saw blade into the plane of the cut.
7. A handsaw as claimed in any of claims I to 6 wherein the force required to actuate the actuation member urges the plane of the saw blade to align and coincide with the plane of the cut.
8. A handsaw as claimed in any of claims I to 7 further comprising an adjustment means to adjust a lateral position of the illuminated indicator relative to the plane of the planar saw blade.
9. A handsaw as claimed in claim 8 wherein the adjustment means enables the illumination means to be rotated about a single axis.
10. A handsaw as claimed in any of claims I to 7 wherein the illumination means is not moveable relative to the handsaw and/or saw blade and/or handle.
11. A handsaw as claimed in any of claims 1 to 10 wherein the plane of the light beam projected from the illumination means does not need to be adjusted relative to the plane of the saw blade.
12. A handsaw as claimed in any of claims I to 11 wherein the illumination means is arranged to project a divergent planar light beam having an angle of divergence substantially 60° and always greater than 22.5°.
13. A method of indicating the cuthng plane of a handsaw comprising; operating illuminating means of the handsaw in order to project an illuminated indicator of the cutting plane on to a surface of a material to be cut: wherein: the method comprises pushing actuation means which is arranged to selectively actuate the illuminating means and wherein the actuation means comprises a push to make non-locking mechanism.
14. The method as claimed in claim 13 comprising indicating a non-perpendicular cut on the material.

15 The method as claimed in any of claims 13 or 14 comprising pushing an actuating member in order to provide the illuminated indicator.