GB2211463A

GB2211463A - A handsawing jig

Info

Publication number: GB2211463A
Application number: GB8724850A
Authority: GB
Inventors: Avais Khan
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-10-23
Filing date: 1987-10-23
Publication date: 1989-07-05
Anticipated expiration: 2007-10-23
Also published as: EP0313410A2; GB2211463B; GB8724850D0

Description

A RAIWAYTIG JIG 2211463 This Invention relates to a handsawing jig and

particularly to a portable handsawing jig suitable for the amateur or DIY carpenter.

Known handsawing jigs such as a mitre-cutting jig comprise, a horizontal platform for supporting a workpiece to be sawn; a saw guiAe assembly for holding a saw in a vertical plane and guiding it during sawing; and means for enabling a workpiece supported by the sawing platform to be positioned at a variety of angles with respect to the line of sawing. This is done by pivotably mounting the saw guide assembly so that It and the saw held within it can be rotated about a vertical axis. Alternatively, the saw guide may be fixed and the workpiece held at a variety of set angles with respect to the line of sawing by means of pegs inserted into holes provided in the sawing platform, the pegs providing a back-stop support for the workpiece at an angle determined by the positions of the holes in which they are located.

Such handsawing jigs enable the amateur carpenter to make accurate crosscuts at a variety of angles to the length of a workpiece, for instance the nitre cuts required to make the corners of a picture frame. However, the range of saw cuts which can be made easily with such handsawing jigs is severely limited.

Thus according to the present invention there is provided a handsawing Jig comprising one or more sawing platforms and one or more saw guide assemblies which are positioned or positionable with respect to each other such that, in a -f irst mode of use, saw cuts can be made into a workpiece In a direction perpendicular to the sawing platform on which It is positioned and, in a second mode of use, saw cuts can be made into a workpiece in a direction parallel to the plane of the sawing platform on which It is positioned, first adjustment means being provided to enable the angular position of a workpiece about the normal to the respective sawing platform to be adjusted relative to the line of sawing in the first mode of use and second adjustment means being provided to enable the position of a workpiece relative to the line of sawing to be adjusted across the plane of sawing in the second mode of use.

Such a handsawing jig can be used to make a much fuller range of saw cuts than is possible with known handsawing Jigs as it enables saw cuts to be made along the grain or parallel to the length of a workplece as well as cuts across the workpiece.

Preferred features of the invention will be apparent from the following description and from the subsidiary claims of the specification.

For ease of description, the terms 'vertical' and 'horizontal' used throughout this specification are to be understood to refer to directions with respect to the surface of a normal workbench or table. In addition, the term line of sawing' is to be understood to refer to the line along which the saw teeth pass during a sawing action, the &plane of sawing' is to be understood to refer to the plane of the saw and hence the saw cut produced and the 'direction' of a saw cut is to be understood as the direction in which the saw moves into the workpiece, ie the direction of a saw cut is perpendicular to the line of sawing but within the plane of sawing.

The invention will now be further described, merely by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a schematic perspective view of a preferred embodiment of a handsawing jig according to the invention; and Figures 2A to 2K are perspective views illustrating a number of different saw cuts and types of joint which can be formed using a handsawing jig such as that shown in Figure 1.

The handsawing j ig shown in Figure 1 comprises a base 1 clamped to a workbench or table 2, a horizontal sawing platform 3 for supporting a workpiece to be sawn and a saw guide assembly 4 pivotably supported by first and second mountings 5A and 5B slidably supported on f Irst and second rods 6A and 6B positioned on opposite sides of the base 1.

The saw guide assembly 4 comprises first and second pairs of rods 7A and 7B with first and second sliding saw guides 8A and 8B positioned between each pair of rods for guiding a saw during sawing. The saw guides 8A and 8B are slidably mounted on one of each of the pairs of rods and are similar to a conventional type of saw guide so will not be described further. The two pairs of rods 7A and 7B are secured to respective support blocks 9A and 9B, which are pivotably mounted by horizontal spindles 10A and 10B to the first and second mountings 5A and 5B, and the ends of at least one of each of the pairs of rods 7A and TB remote from the support blocks 9A and 9B are rigidly secured to each other by a connecting bar 11. A notch ia also provided near each end of the connecting bar 11 for stabalising the respective saw guides 8A and 8B as shown in Figure 1.

The saw guide assembly 4 Is thus rotatable as a unit by this inclination adjustment means about a horizontal axis passing through the two spindles 10A and 10B in the mountings 5A and 5B. An arm 12 attached to the spindle 10B is provided to hold the saw guide assembly at selected angles about the horizontal axis. In the arrangement shown, the arm 12 abuts a stop formed by a flange 13 provided on the mounting 5B when the saw guide assembly 4 is in the vertical position and is held in this position by a clamping device 14. The clamping device 14 comprises a spring-loaded plunger which engages with holes provided in the side of the mounting 5B. The holes 15 visible in Figure 1 are for clamping the saw guide assembly at 45 to the vertical and in a horizontal position, repectively. More holes may be provided to enable the saw guide assembly to be held at a number of other angles. Alternatively, a different form of clamping device (not shown) can be used which enables the saw guide assembly to be clamped at any angle between the vertical and horizontal positions.

As mentioned above, the saw guide assembly 4 is slidably mounted on upright rods 6A and 6B. The position of the saw guide assembly 4 above the sawing platform 3 can be adjusted by a worm drive mechanism 16. Operation of the mechanism 16 moves the saw guide assembly 4 up or down the rods 6A and 6B and thus adjusts the perpendicular spacing, in this case the vertical spacing, between the saw guide assembly 4 and the sawing platform 3. The position of a workpiece on the sawing platform relative to the line of sawing when the saw guide assembly is In a horizontal position can thus be adjusted across the plane of sawing. As will be described in more detail below, the worm drive mechanism 16 can also be used as a depth guide to control the depth of the saw cut made.

The saw guide assembly 4 is rotatable about a vertical axis by first adjustment means comprising a cross-nenber 17 pivotably mounted to the un6rside of the sawing platform 3. The rods 6A and GB are mounted an opposite ends of the cross-member 17 so as this Is rotated about a vertical axis the entire_ saw guide assembly 4 is rotated with it. The assembly can be clamped at selected angles about the vertical axis by means of a further clamping device 18 mounted on the crossmember 18 and which engages with notches provided in an arcuate portion 19 of the sawing platform 3. This mechanism for rotating and clamping the saw guide assembly 4 about a vertical axis is similar to that used in conventional mitre-cutting jigs.

In a f irst mode of use, a workpiece (not shown) is supported on the sawing platform 3 and positioned against a back-stop provided by a fixed rail 20 and two swivelling posts 21 which can be swung into a horizonal position when they are not required. A saw 22 is fitted within the saw guides BA and 8B and the saw guide assembly 4 clamped at a selected angle about the vertical axis. With the saw guide assembly 4 in the vertical position and the line of sawing perpendicular to the back-stop support rail 20 as shown, the jig will be set up to enable a simple cross-cut (see Figure 2A) to be formed. The backward and forward notion of the saw 22 is guided by the saw guides BA and 8B. The saw guide assembly 4 is, of course, initially raised by the worm drive mechanism 16 to allow the workpiece to be positioned between the saw and the sawing platform 3 before a saw cut i s made. However, by careful adjustment of the worm drive mechanism 16 it can also be used to limit the depth of saw cut that can be made by positioning the saw guide assembly at such a height that the lowest position that the saw held within the saw guides BA and 8B can be moved down to corresponds to the depth of saw cut required.

A cross-cut at an angle across the workpiece, such as a mitre cut (see Figure 2B) required in the fabrication of a picture frame, can be made with the saw guide assembly 4 in the vertical position as described above but rotated about the vertical axis so tbat the line of sawing is at 45 to the length of a workpiece held against the back-stop rail 20.

This mode of use of the handsawing jig to form saw cuts as illustrated in Figures 2A and 2B in which the saw cut is made into the workpiece in a direction perpendicular to the sawing platform an which the workpiece is positioned corresponds to the manner in which a conventional handsawing jig can be used.

It is, however, frequently necessary for the amateur carpenter to make other types of saw cuts such as bevel cuts (ie cuts inclined to the vertical - see Figure 2C), for instance to the end of a skirting board or the frame of a bookshelf. To make such a out, the saw guide assembly 4 is positioned as shown in Figure 1 with the line of sawing at right angles to the back-stop rail 20 and is then rotated away from the vertical by an angle of 45 and secured in this position by the clamping device 14. The height of the saw guide assembly 4 above the sawing platform 3 is then adjusted as necessary by means of the worndrive mechanism 16 to position the saw blade against the part of the workplece which Is to be sawn. The Jig is then set up so that a saw cut can be made into the workpiece in a direction inclined to the vertical so that an accurate bevel cut can be made.

In some cases, it might be possible to make the same cut by positioning the workplece on its edge and making a mitre cut as described above. However, this Is not possible with many conventional handsawing jigs since they are unable to accomodate the width of the workplece in this orientation between the sawing platform and the saw.

For making a saw cut in a direction parallel to the plane of the sawing platform on which the workpiece is positioned, for instance into the end of a workpiece and parallel to its length as required for a half lap joint (see Figure 2D), the saw guide assembly is positioned as shown in Figure 1 and then rotated 90 about the horizontal axis so the saw 22 lies in a horizontal plane and the saw guide assembly is then clamped in this position. The back-stop posts 21 are also swung out of the way so they do not obstruct the saw. The height of the raw guide assembly 4 is then adjusted so that the saw cut is made at the desired position in the end of the workpiece. In this second mode Of use, the sawing j ig is thus set up to enable an accurate saw cut to be made in the end of the workpiece in a direction parallel to the plane of the sawing platform 3.

Conpound cuts, le cuts in which the workpiece is at an angle to the line of sawing an& the cut is inclined to the vertical (see Figure 2M, can also be made with this jig. This is done by rotating the saw guide assembly about the vertical axis so that the line of sawing is at a chosen angle with repect to the length of a workpiece held against the back-stop rail 20, then rotating the saw guide assembly 4 about the horizontal axis to the desired angle and clamping it in position and then adjusting the height of the saw guide assembly 4 to position the saw blade against the workpiece.

It will be appreciated that by means of adjustments such as those described above a very wide range of saw cuts can be made using this handsawing jig. Cross-cuts may be made at a variety of angles up to at least 45 on either side of the perpendicular to the back-stop rail 20 by rotating the saw guide assembly 4 about the vertical axis and bevel cuts can be made at any angle up to at least 90 to the vertical by rotation of the saw guide assembly 4 about the horizontal axis. Cuts can also be made at selected positions and at selected angles in the end of a workpiece by vertical adjustment of the saw guide assembly 4 with respect to the workpiece and rotating the saw guide assembly 4 about the horizontal axis to the desired angle. The saw guide assembly nay also be rotated about the vertical axis whilst in the horizontal position to enable angled cuts to be made into the end of the workpiece such as those required to form the joint illustrated in Figure 2L. As the workpiece is held in a horizontal position when saw cuts are made into its end, this type of saw cut can be made in workpieces of any length.

Rigure 1 also shows a second sawing platform 23 which lies In a vertical plane and which, in use, 16 slidably mounted on horizontal bare 24 extending across the front of the jig so that the lateral position of the sawing platform 23 and hence the workpiece thereon can be adjusted relative to the saw guide assembly 4. A clamp 25 is provided for holding a workpiece an the sawing platform 23 against a vertical flange 26 projecting from an edge thereof. Clamping means (not shown) may also be provided to secure the sawing platform 23 in a desired position along the bars 24.

The vertical sawing platform 23 can also be used when saw cuts are to be made into the end of a workpiece. The workpiece is placed on the sawing platform 23 so that the upper end of the workpiece projects a short distance above the platform and clamped in place. The sawing platform is then slid sideways on the bars 24 so that the position of the workpiece relative to the line of sawing can be adjusted across the plane of sawing. The workpiece can thus be moved to a position beneath the saw. When the saw guide assembly 4 is in the position shown in Figure 1, a saw cut in a vertical plane can be made into the end of the workpiece. The saw guide assembly can also be rotated about the horizontal axis and/or the vertical axis to enable saw cuts inclined to the vertical and/or at an angle across the end of the workpiece to be made, eg for a dovetail joint (see Figure 2F).

As an alternative to rotating the saw guide assembly about the vertical axis to make angled cross-cuts in the end of a workpiece, a wedge-piece (not shown) can be placed between the workpiece and the vertical sawing platform 23 so that the workpiece is held at an angle to the plane of the sawing platform 23. Such wedge-pieces can also be used for adjusting the angle that a workplece is held against the back-stop rail 20 described above or the angle at which a workpiece lies on the horizontal sawing platform 3.

Use of the vertical sawing platform 23 thus provides another way in which saw cuts can be made into a workpiece in a direction parallel to the plate of the sawing platform on which the workpiece is positioned. In this case, however, the plane of sawing is perpendicular or inclined to the plane of the sawing platform in contrast to the arrangement described above using the horizontal sawing platforn and the saw guide assembly in a horizontal position in which' the plane of sawing Is parallel to the plane of the sawing platform.

Other adjustment means for enabling the line of sawing to be positioned at a variety of angles relative to the workiece positioned on the horizontal sawing platform 3 can be envisaged. This can be done by adjusting the angle of the back-stop rail 20 rather than the saw guide assembly 4. For instance, the sawing platform 3 may carry a fixed a back- stop support rail and the whole platform mounted so as to be rotatable about a vertical axis. Alternatively, the sawing platform 3 may be fixed and a backstop rail mounted thereon so as to be rotatable about a vertical axis. Many other arrangements including the use of pegs positioned within holes in the sawing platform as used in some conventional sawing jigs can also be envisaged.

The perpendicular spacing between the saw guide assembly and the sawing platform has been described as being adjustable by movement of the saw guide assembly. Again, other arrangements can be envisaged for enabling the position of a workpiece relative to the line of sawing to be adjusted across the plane of sawing such as adjustment of the horizontal sawing plaforn itself, eg in a vertical direction.

A variety of different arrangements for the saw guide assembly could be used but the preferred arrangement is to have two saw guides positioned on opposite sides of the horizontal sawing platform with a rigid connection between the two saw guides, the assembly being rotatable as a unit about a horizontal axis. If the saw guide assembly is of a sufficiently rigid construction, it need be pivotably mounted on only one side of the sawing platform. However, the most preferred arrangment Is to provide a pivotable mounting on each side of the sawing platform as this is a more stable construction.

The rigid connection between the two saw guides should be positioned away from the axis of rotation of the -saw guide assembly so as not to obstruct adjustment of the position of a workpiece across this axis. Thus, in the absence of any Interconnection or spindle along the axis of rotation, the saw guide assembly can be freely raised and lowered to a position in which the axis passes through or beneath the sawing platform. If this were not possible, vertical adjustment of the saw giude assembly would be severely limited and it would be difficult to make the full range of saw cuts into the end of a long or wide workpiece. The U- shaped saw guide assembly shown in Figure 1 is an example of the most preferred arrangement.

A drill guide (not shown) nay also be provided on the saw guide assembly 4 to enable dowel holes to be made in a workpiece when dowel Joints such as those shown in Figures 2J and 2K are to be formed. The drill guide may comprise a guide block which 16 slidably mounted on the connecting bar 11 with guide holes of different diameters passing through it at different angles. With the saw guide assembly and the guide block clamped in approriate positions, a drill bit can be inserted through one of the holes to be guided thereby as it is used to drill a hole in a workpiece.

It could also be envisaged that the inclination adjustment means for enabling bevel cuts to be made as well as cuts Into the end of a workpiece may comprise means for rotating the sawing platform about a horizontal axis whilst the saw guide assembly remains in a vertical position. However, the Illustrated inclination adjustment means in which the saw guide assembly is rotatable about a horizontal axis is much preferred in view of its simplicity and convenience of use. It would also be possible to provide two saw guide assemblies, one which is fixed in a vertical position for use in making saw cuts in a direction perpendicular to the horizontal sawing platform and the other fixed in a horizontal position for use in making saw cuts In a direction parallel to the horizontal sawing platform.

The saw 22 is preferably a bow saw having the provision for removing and replacing the saw blade. Filing attachments (not shown) may the be provided which can be f itted to such a saw in place of the saw blade. In this case, the saw guides 8A and 8B should be shaped so as to- be able to guide a saw fitted with a filing attachment or to be able to guide a conventional f ile used in place of the saw. A range of filing attachments or conventional files of different sizes and roughnesses can, of course, be used. Other tools such as a rasp file.

-10grinding stone file or a detachable sanding strip can also be attached to the saw In this way. Such attachments can be used to make fine adjustments to saw cuts already made and to help form channels and slots or enlarge holes in the workpiece.

By the use of a saw followed by the use of such filing attachments, or other tools, an amateur carpenter is able to undertake precision jointmaking with this handsawing jig. Joints, such as a mitre joint with insert tongue, a mortice and tenon joint, a through dovetail housed Joint, a nitre joint with dowels, a simple dowel Joint, a bridle and mitre Joint and a simple through housed joint, which can be made using this handsawing jig are shown in Figures 2G to 2X.

The handsawing jig illustrated is preferably portable so that it can be easily carried about and is provided with securing means 27 for releasably securing it to a workbench or table as and when required by an amateur or DIY carpenter.

Claims

1. A handsawing Jig comprising one or more sawing platforms and one or more saw guide assemblies which are positioned or positionable with respect to each other such that, In a f irst mode of use, saw cuts can be made into a workpiece in a direction perpendicular to the saling platform on which it is positioned and, in a second mode of uses saw cuts can be made Into a workplece In a direction parallel to the plane of the sawing platform on which It is positioned, first adjustment means being provided to enable the angular position of a workpiece about the normal to the respective sawing platform to be adjusted relative to the line of sawing In the first mode of use and second adjustment means being provided to enable the position of a workpiece relative to the line of sawing to be adjusted across the plane of sawing in the second node of use.

2. A handsawing Jig as claimed in claim 1 comprising a first sawing platform; a single saw guide assembly; and inclination adjustment means for enabling the saw guide assembly to be rotated relative to the first sawing platform about a horizontal axis between a first position in which saw cuts can be made into a workpiece on the first sawing platform in a direction perpendicular to the first sawing platform and other positions in which saw cuts can be made into a workpiece on the first sawing platform in directions inclined to the said perpendicular.

3. A handsawing Jig as clained in claim 2 in which the saw guide assembly can be rotated relative to the first sawing platform about the said horizontal axis to a second position in which saw cuts can be made into a workpiece on the first sawing platform In a direction parallel to the plane of the first sawing platform.

4. A handsawing Jig as claimed in claim 2 or 3 In which the first adjustment means comprises means for rotating the saw guide assembly relative to the first sawing platform about an axis perpendicular to the first sawing platform.

5. A handsawing Jig as claimed in claim 2, 3 or 4 in which the second adjustment means comprises means for adjusting the perpendicular spacing between the first sawing platform and the saw guide assembly.

6. A handsawing Jig as claimed in any of claims 2 to 5 comprising a second sawing platform lying in a vertical plane so that saw cuts can be made into a workpiece on the second sawing platform in a direction parallel to the plane of the second sawing platform.

7. A handsawing Jig as claimed In claim 6 comprising further adjustment means for moving the second sawing platform to enable the position of a workpiece on the second sawing platform to be adjusted across the plane of sawing.

8. A handsawing Jig as claimed in claims 1 to 5 which comprises a first sawing platform lying in a horizontal plane, a saw guide assembly for enabling saw cuts to be made Into a workpiece an the first sawing platform in a vertical direction and first adjustment means for rotating the saw guide assembly about a vertical axis to enable the angular position of a workpiece on the first sawing platform to be adjusted relative to the line of sawing as known per se, characterised by Inclination adjustment means for enabling the saw guide assembly to be rotated about a horizontal axis between a first position in which saw cuts can be made into a workpiece on the f irst sawing platform in a vertical direction and a second position in which saw cuts can be made into a workpiece on the f irst sawing platform in a horizontal direction and by second adjustment means for enabling the vertical spacing between the saw guide assembly and the first sawing platform to be adjusted.

9. A handsawing Jig as claimed in claims 2, 6 and 7 or as claimed in claim 8 which comprises a first sawing platform lying in a horizontal plane, a saw guide assembly for enabling saw cuts to be made into a workpiece on the first sawing platform in a vertical direction and first adjustment means for rotating the saw guide assembly about a vertical axis to enable the angular position of a workpiece an the first sawing platform to be adjusted relative to the line of sawing as known per se, characterised by inclination adjustment means for -13enabling the saw guide assembly to be rotated about a horizontal axis between a first position In which saw cuts can be made into a workplece on the first sawing platform In a vertical direction and other positions in which saw cuts can be made into a worpiece an the first sawing platform in directions inclined to the vertical, a second sawing platform lying in a vertical plane so that saw cuts can be made Into a workplece on the second sawing platform In a vertical direction and in directions Inclined to the vertical and by adjustment means for moving the second platform In a horizontal direction so as to enable the lateral position of the second sawing platform to be adjusted relative to the saw guide assembly.

10. A handsawing jig as clained In any preceding c laim in which the or each saw guide assembly comprises two saw guides positioned an opposite sides of the or a first sawing platform and a rigid connection between the two saw guides which is positioned so as not to obstruct the adjustment of the position of a workpiece across the plane of sawing in the second mode of use.

11. A handsawing jig as claimed in claim 10 In which the saw guide assembly is provided with means for guiding a file or a saw fitted with a filing attachment as well as a conventional saw.

12. A handsawing Jig as claimed in any preceding claim which is portable and comprises securing means for releasably securing it to a workbench or table.

13. A handsawing Jig substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.

Published 1989 at The Patent Offtce, State House, 66171 Holborn, Londor. WO1A 4TP. Purther copies may be obtainedfrom The Patent Office. Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray. Rent, Con. 1187