GB1573301A

GB1573301A - Saw guide apparatus

Info

Publication number: GB1573301A
Application number: GB176A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-03-30
Filing date: 1977-03-30
Publication date: 1980-08-20

Description

(54) IMPROVEMENTS IN OR RELATING TO SAW GUIDE APPARATUS (71) I, GORDON WILLIAMS WYNN, a British subject of The Glebe, Holton cum Beckering, Lincoln, Lincolnshire, LN3 5NG, do hereby declare the invention for which I pray that a patent may be granted to me and the method by which it is to be performed to be particularly described in and by the following statement This invention relates to saw guide apparatus for use in sawing operations on workpiece. Such apparatus is known comprising means for locating the workpiece angularly relative to one or more saw guide devices of the apparatus so that a correspondingly angled saw cut can be made in the workpiece.

According to the present invention, there is provided saw guide apparatus having at least one saw guide device comprising a rigid member providing a guide face for a saw blade and a biasing member having a supporting part through a lower region of which it is secured in place and means projecting towards the rigid member from said supporting part to urge the saw blade against said guide face, said projecting means comprising an inclined first portion extending downwardly from a region of said supporting part on which it is angularly displaceable, said portion being inwardly inclined towards said guide face, and a second portion extending from the lower end of said first portion outwardly away from said guide face.

The biasing member may be made of a resilient material with said projecting means as an integral cantilevered part, but it may be so constructed that the main part of the member is itself rigid, the projecting means being provided by an element that is resilient or is resiliently yieldably mounted on said main portion.

The projecting means may have a form in which, as seen in the direction of the depth of saw cut, at least that part in the region of the junction of the first and second portions is inclined away from the saw guide face at one or both side margins so as to provide a corresponding lead-in for the front and/or rear edge of the saw blade. The projecting means may thus be given a bulbous profile both as seen in the direction of saw blade motion (by virtue of the inclinations of the first and second portions) and transverse thereto in the direction of saw depth cut (by virtue of said inclination at the junction of the first and second portions).

The inclination or inclinations at said junction of the first and second portions may be curved, to give the surface of the projecting means facing the saw guide face a generally convex form as seen in the direction of the depth of saw cut, or a rectilinear inclination or inclinations can be provided, in a manner of a bevel, the resultant profile in each instance being with or without a central flat region.

The invention will be more particularly described by way of example with reference to the accompanying drawings, wherein : Figure 1 is a perspective view of a location apparatus according to the invention.

Figure 2 is a plan view of the apparatus of Figure 1, Figure 3 is a sectional view on the line III-III in Figure 2, Figure 4 and 5 are front and plan views respectively of another biasing member, intended for a further saw guide apparatus according to the invention Figure 6 illustrates a further modified form of biasing member for apparatus according to the invention, and Figure 7 to 9 are detail views of another form of saw guide member for apparatus according to the invention, showing the projecting means of the member and its manner of displacement.

Referring to Figures 1 to 3 of the drawings, the apparatus comprises a support means in the form of a diecast flat-topped unitary base or support plate 2 offset towards the right-hand side edge of which two saw guide devices 4, 4a are mounted. Each device comprises a pair of upright limbs 6, 8.

The limb 6 is a rigid construction providing a fixed, wear-resistant saw guide face 10 opposed to the other limb 8, and the two columns are so arranged on the base that the faces 10 are co-planar and define the saw guide plane.

The limb 6 of each guide device may take any of the forms described in my co-pending patent application No. 1506 383. The other limb 8 of each guide device is a unitary resilient member, e.g. a nylon moulding, having at its lower end a seating element by which it is secured to the base and having at its upper end an integral offset cantilever projection or nose 12 comprising an upper portion 12a inclined downwardly and towards the face 10 and a lower return portion 12b, the projection bearing on the adjacent face 10 so that the limb 8 acts as a spring biasing a hand saw blade inserted in the guide devices against the location plane formed by the faces 10, with the cantilever projection flexing resiliently about its upper junction region with the main part of the limb 8.

The construction of the projection 12 allows a hand saw blade to be pushed into the gap between the limbs simply by downwards pressure on the saw and also, in the case of a tapered saw blade that has been overstroked so that the back edge of the blade has slipped below the projection for example, it allows the blade to be reengaged upwards with equal facility and without any risk of the teeth being caught or trapped. In each instance, the pressure of the saw blade on the projection, whether upwards or downwards, tends to urge the projection away from the guide face by pivoting the projection resiliently at its upper region.

Running right across the base 2 between the columns 4, 4a is a groove 14 interrupted by replaceable nylon pads 18 set into the surface of the base to ensure that the saw teeth are not damaged by, nor themselves damage, the base when the workpiece is sawn through.

In the upper face of the base 2 there are a number of accurately sized location holes 21 and 26 able to receive removable location pins 16. By mounting a plurality of location pins 16 in different ones of the holes 21 to 26 location positions can be established for a side face of an elongate workpiece at a number of different angular positions relative to the saw guide plane for a saw cut to be made in the workpiece at accurately predetermined angles relative to the located side face. Examples are shown in Figure 2 of a workpiece W1 at right angles to the saw guide plane and a further workpiece W2 at 45O to the saw guide plane.

To hold the apparatus steady on a workbench, it has rubber pads 32, but it can also be provided with means, e.g. clamping screws, to fix it in place, and apertures 34 are provided in the base into which the head of a G-clamp can be inserted to clamp the workpiece. Oppositely inclined 45O mitres can be cut with the workpiece extending to the same side of the saw guide plane, so that the operator can himself hold the workpiece for either cut without having to adopt a constrained position. The apparatus is moreover capable of being used in the same way, whether the operator is right-handed or left-handed.

In each saw guide device, the resilient limb 8 is mounted separately from the rigid limb 6 and is clipped into position in a slot 42 in the base by a bifurcated lower end 44.

The rigid limb itself has a transverse crosssection of equilateral triangular form and its main part is provided by an extruded tube 46 of wear-resistant plastics material that seats in, to be supported and located angularly by, a recess 48 in the base. The tube is fixed in place by a top plate 50, a securing screw 52 extending through the top plate and the base and a nut 54 threaded onto the screw being tightened against the undersurface of the base to clamp the tube firmly in place. The tube can be turned, when a side face becomes worn with use, to bring a fresh side face opposite the resilient limb, as is described in more detail in co-pending application No. 1506 383 where various modified versions of this arrangement are also disclosed.

The top plate may be provided with at least one additional aperture to receive an adjustable depth stop device projecting upwards from the limb 6 that will provide a limiting abutment for the back or spine of a tenon saw.

While the embodiment illustrated in Figures 1 to 3 shows apparatus provided with a support base on which the workpiece is located, it should be appreciated that the saw guide devices can also be mounted on a different form of carrier to provide saw guide apparatus of a form which is located upon and supported by the workpiece itself.

Thus, Figures 4 and 5 illustrate a saw guide member of a modified form to that shown in Figures 1 to 3 and intended for a saw guide apparatus of the form described in my co-pending application 1502596. That apparatus comprises a pintle on which boss 62 of the illustrated guide member 60 is a snap fit and which holds the member so that its integral cantilevered projection 64 bears against a rigid saw guide face (not shown).

As is described in my earlier application. the snap-fit arrangement allows the guide member to be pivotable about an axis normal to the saw guide plane to expose the rigid guide face as when that face is to be used for gauging purposes.

The member 60 has a modified form of projection 64 that can also be used in the other illustrated embodiments. In this, the foremost region 66 of the projection appears bulbous in plan view, the side margins 68 of the projection over the transition region between its first and second portions 70, 72 being inclined away from the saw guide face. The inclinations serve to allow a saw blade to slip more easily into the space between the saw guide members from either side, so that if the saw leaves that space momentarily it will not necessarily interrupt the sawing rhythm.

It may be possible to have an inclination only on one side margin but it is preferable for them to be on both margins for similar use in left-handed and right-handed operation as described above. It may or may not be desired to have a central flat on the leading face of the projection between the inclinations and, although the inclinations are shown curved they may alternatively be rectilinear, in the manner of a bevel, or even slightly concave while still being inclined away from the saw guide face.

Figure 6 illustrates a modification in which the cantilever projection 80 is a separate element and is displaceable on its guide member 82 to be able to engage a saw blade at an adjustable height. The projection has side flanges 84 frictionally gripped in opposed recesses 86 of main channel section 88 of the guide member and the nose 90 of the projection extends forwardly from the open front face 92 of the channel section. It is alternatively possible to provide an adjustable projection that is positively secured in place, e.g. by a clamping screw.

It will be noted that in the arrangement shown in Figure 6, the guide member 82 is not necessarily resilient, and the resilience of the member is provided by the projection alone. It is possible thus to obtain the required resilient effect with a biasing member having a main rigid portion on which a resilient portion is secured or on which such a resilient portion or a further rigid portion is resiliently mounted.

Figures 7 to 9 illustrate a further example of this. Here the biasing limb of the saw guide device is in the form of an upright member having a cranked part 94 extending towards the guide face 10. The cranked part may be fixed in place or be upwardly and downwardly adjustable, analogously to the preceding example, and it is spaced for the guide face. It carries a resilient element 96 that biases a saw blade B against the guide face. The element 96 comprises inclined first and second portions 98, 100 similarly to the projections already described and like those projections it can also have inclined front and/or rear margins in plan view. The element 96 is held in the direction of saw stroke by side portions 102 that grip the front and rear faces of the part 94 but that do not prevent pivoting of the element about either of the edges 104, 106 of the part 94. To retain the element 96 on the part 94 for such pivoting movements, engagement lips 108 are provided at the free ends of the first and second portions 98, 100. If desired, beads may be provided on the upper and lower end edges of the part 94, fitting in the recesses formed by the lips 108, to hold the element 96 more securely.

As will be clear from Figures 8 and 9, the movement of the saw blade downwardly or upwardly while pushing the element 96 away from the guide face will tend to pivot the element about the lower edge 106 or the upper edge 104 respectively of the part 94. It will be appreciated that such pivoting is accompanied by some slight movement of the element 96 away from the guide face, so countering any tendency of the saw blade to jam, while deforming the projection so that it tends to be urged back to its central position. A similar arrangement can be provided for allowing the resilient element to pivot about the side edges of the cranked part 94 but it is generally more important to cater for free entry of the saw blade between the guide face and the resilient element from above, as when starting a saw cut, and from below, as when overstroking with a tapered blade in the manner referred to above.

It is a feature of the embodiments described above that the saw guide columns are removable and it is thus possible to make a relatively compact package for transport and storage of the apparatus. For this purpose also, stowages can be provided for the columns in the base of the apparatus of Figures 1 to 3 so that they lay flat within the base.

Many modifications of the illustrated constructions are of course possible within the scope of the present invention. Clearly, the cross-sectional shapes of the saw guide members can take many different forms other than triangular shapes illustrated, and there is a wide choice of materials from which they may be made. Preferably at last the biasing guide members are so mounted, as by the push-fit connections described, that they can be removed and replaced without needing tools for fastening devices such as nuts or screws.

WHAT I CLAIM IS: 1. Saw guide apparatus having at least one saw guide device comprising a rigid

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. snap-fit arrangement allows the guide member to be pivotable about an axis normal to the saw guide plane to expose the rigid guide face as when that face is to be used for gauging purposes. The member 60 has a modified form of projection 64 that can also be used in the other illustrated embodiments. In this, the foremost region 66 of the projection appears bulbous in plan view, the side margins 68 of the projection over the transition region between its first and second portions 70, 72 being inclined away from the saw guide face. The inclinations serve to allow a saw blade to slip more easily into the space between the saw guide members from either side, so that if the saw leaves that space momentarily it will not necessarily interrupt the sawing rhythm. It may be possible to have an inclination only on one side margin but it is preferable for them to be on both margins for similar use in left-handed and right-handed operation as described above. It may or may not be desired to have a central flat on the leading face of the projection between the inclinations and, although the inclinations are shown curved they may alternatively be rectilinear, in the manner of a bevel, or even slightly concave while still being inclined away from the saw guide face. Figure 6 illustrates a modification in which the cantilever projection 80 is a separate element and is displaceable on its guide member 82 to be able to engage a saw blade at an adjustable height. The projection has side flanges 84 frictionally gripped in opposed recesses 86 of main channel section 88 of the guide member and the nose 90 of the projection extends forwardly from the open front face 92 of the channel section. It is alternatively possible to provide an adjustable projection that is positively secured in place, e.g. by a clamping screw. It will be noted that in the arrangement shown in Figure 6, the guide member 82 is not necessarily resilient, and the resilience of the member is provided by the projection alone. It is possible thus to obtain the required resilient effect with a biasing member having a main rigid portion on which a resilient portion is secured or on which such a resilient portion or a further rigid portion is resiliently mounted. Figures 7 to 9 illustrate a further example of this. Here the biasing limb of the saw guide device is in the form of an upright member having a cranked part 94 extending towards the guide face 10. The cranked part may be fixed in place or be upwardly and downwardly adjustable, analogously to the preceding example, and it is spaced for the guide face. It carries a resilient element 96 that biases a saw blade B against the guide face. The element 96 comprises inclined first and second portions 98, 100 similarly to the projections already described and like those projections it can also have inclined front and/or rear margins in plan view. The element 96 is held in the direction of saw stroke by side portions 102 that grip the front and rear faces of the part 94 but that do not prevent pivoting of the element about either of the edges 104, 106 of the part 94. To retain the element 96 on the part 94 for such pivoting movements, engagement lips 108 are provided at the free ends of the first and second portions 98, 100. If desired, beads may be provided on the upper and lower end edges of the part 94, fitting in the recesses formed by the lips 108, to hold the element 96 more securely. As will be clear from Figures 8 and 9, the movement of the saw blade downwardly or upwardly while pushing the element 96 away from the guide face will tend to pivot the element about the lower edge 106 or the upper edge 104 respectively of the part 94. It will be appreciated that such pivoting is accompanied by some slight movement of the element 96 away from the guide face, so countering any tendency of the saw blade to jam, while deforming the projection so that it tends to be urged back to its central position. A similar arrangement can be provided for allowing the resilient element to pivot about the side edges of the cranked part 94 but it is generally more important to cater for free entry of the saw blade between the guide face and the resilient element from above, as when starting a saw cut, and from below, as when overstroking with a tapered blade in the manner referred to above. It is a feature of the embodiments described above that the saw guide columns are removable and it is thus possible to make a relatively compact package for transport and storage of the apparatus. For this purpose also, stowages can be provided for the columns in the base of the apparatus of Figures 1 to 3 so that they lay flat within the base. Many modifications of the illustrated constructions are of course possible within the scope of the present invention. Clearly, the cross-sectional shapes of the saw guide members can take many different forms other than triangular shapes illustrated, and there is a wide choice of materials from which they may be made. Preferably at last the biasing guide members are so mounted, as by the push-fit connections described, that they can be removed and replaced without needing tools for fastening devices such as nuts or screws. WHAT I CLAIM IS:

1. Saw guide apparatus having at least one saw guide device comprising a rigid

member providing a guide face for a saw blade and a biasing member having a supporting part through a lower region of which it is secured in place and means projecting towards the rigid member from said supporting part to urge the saw blade against said guide face, said projecting means comprising an inclined first portion extending downwardly from a region of said supporting part on which it is angularly displaceable, said portion being inwardly inclined towards said guide face, and a second portion extending from the lower end of said first portion outwardly away from said guide face.

2. Apparatus according to claim 1 wherein at least that part of the projecting means at the transition between said first and second portions has its one or both side margins inclined away from said guide face to provide a tapering lead-in for the saw blade at said one or both side margins between the projecting means and the guide face.

3. Apparatus according to claim 2 wherein the or each said side margin inclination is of generally convexly curved form.

4. Apparatus according to claim 2 wherein the or each said side margin inclination is of rectilinear form.

5. Apparatus according to any one of claims 2 to 4 wherein laterally inwardly of said side margin or margins the projecting means has a flat blade-contacting region.

6. Apparatus according to any one of the preceding claims wherein the biasing member is arranged to be removably secured in place without the use of tools.

7. Apparatus according to claim 6 wherein snap-fitting means are provided to secure the biasing member in place.

8. Apparatus according to any one of the preceding claims wherein the biasing member comprises a substantially rigid mounting portion for said projecting means.

9. Apparatus according to claim 8 wherein said projecting means is formed of a resiliently yieldable material.

10. Apparatus according to claim 9 wherein said projecting means is of a plastics material.

11. Apparatus according to any one of claims 8 to 10 wherein said projecting means is resiliently attached to said mounting portion.

12. Apparatus according to any one of the preceding claims wherein the projecting means is upwardly and downwardly adjustable.

13. Apparatus according to claim 12 wherein the projecting means is arranged to be frictionally engaged in its position of adjustment.

14. Apparatus according to claim 12 wherein the projecting means is arranged to be positively fixed in its position of adjustment.

15. Apparatus according to any one of claims 8 to 14 wherein the projecting means is resiliently pivotable away from the guide face both about its upper and lower end regions.

16. Apparatus according to any one of claims 1 to 14 wherein the projecting means is cantilevered from said region of pivoting on the supporting part.

17. Apparatus according to any one of claims 1 to 7 wherein the biasing member including said projecting means is an integral plastics moulding.

18. Saw guide apparatus constructed and arranged for use and operation substantially as described herein with reference to Figures 1 to 3 or Figures 4 and 5 or Figure 6 or Figures 7 to 9 of the accompanying drawings.