GB2071537A - Dowelling jig - Google Patents

Abstract

A dowelling jig is provided comprising first and second members 1, 2 having opposing parallel surfaces for receiving therebetween a first generally flat workpiece 14. The first member has a portion 5 extending perpendicularly from the parallel surfaces for abutting against the edge of a second workpiece 15. The second member has at least one hole 8 for guiding a drill bit with an axis perpendicular to the parallel surfaces. The first member has at least one hole 6 for guiding a drill bit with an axis perpendicular to the portion 5. <IMAGE>

Description

SPECIFICATION Improvements in or relating to dowelling tools The present invention relates to dowelling tools. Such tools may be used for guiding the cutting of holes in two wooden workpieces so that the holes in one workpiece line up with the holes in the other workpiece for receiving dowels to connect the workpieces together.

According to the invention, there is provided a dowelling tool comprising first and second members having respective opposing parallel surfaces for receiving therebetween a first generally flat workpiece, the first member having a part or portion extending substantially perpendicularly from the parallel surfaces for abutting against an edge of a second generally flat workpiece which second workpiece in use is disposed parallel to the first workpiece, the second member having at least one hole formed therein with an axis perpendicular to the parallel surfaces, and the first member having at least one hole formed therein with an axis perpendicular to the said part of portion of the first workpiece.

The holes are used to guide a drill bit for the formation of holes in the workpieces. The workpieces are disposed one on top of the other, and may be spaced by a spacing part or portion of the first member. First holes are then drilled in the side of the first workpiece and in the edge of the other. The tool is then moved along the edge of the workpieces and further holes drilled while maintaining the workpieces in the same relative positions. Thus, when the drilled end of the second workpiece is lined up with the drilled side of the first workpiece, the respective sets of holes are aligned for receiving dowels.

Preferably, the axes of the holes or each pair of corresponding holes in the first and second members intersect. Thus, during drilling of holes in the two workpieces, these holes are formed in alignment with each other, so that the side edges of the workpieces are aligned during this operation.

Preferably, the first and second members are interconnected by means permitting relative movement therebetween. Such means may serve as a stop for the edge of the first workpiece. The holes in the first and second members are preferably disposed so that the distance of a hole formed in the first workpiece from the edge thereof is equal to the distance of a hole formed in the second workpiece from a side thereof.

The invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a dowelling tool constituting a first embodiment of the invention; Figure 2 is a cross-section of the tool of Figure 1 in use; Figure 3 illustrates another use of the tool of Figure 1; Figure 4 shows a dowelling tool constituting a second embodiment of the invention; Figure 5 is an exploded view of a dowelling tool constituting a third embodiment of the invention; and Figure 6 shows the tool of Figure 5 when assembled.

The dowelling tool shown in the accompanying drawings comprises a first member 1 and second member 2 slidably mounted with respect to the first member 1 on bars 3 fixed to the first member.

The first member 1 has a spacer portion 4 extending generally at right angles to a guide portion 5. The guide portion 5 has formed therein two holes 6 of different diameters lined with hardened inserts 7 for guiding drill bits of correspondingly different diameters.

The second member 2 has formed therein two holes 8 also lined with hardened inserts 9 for guiding drill bits. The axes of the holes 8 are perpendicular to the axes of the holes 6 formed in the first member 1. The axis of each hole 9 intersects the axis of a corresponding one of the holes 6 and the holes of each corresponding pair have the same diameter for receiving drill bits of the corresponding diameter. Thus, in the case of the embodiment shown in Figure 1 where the sides 10 and 1 1 of the second member 2 line up with the sides 12 and 13, respectively of the first member 1, the distance of each hole 6 from the nearer side 12 or 1 3 is equal to the distance of the corresponding hole 9 from the nearer side 10 or 11.

Figure 2 shows the dowelling tool of Figure 1 in use for drilling first and second generally flat wooden workpieces 14 and 15. The first workpiece 14 is arranged parallel to and above the second workpiece 15 with the spacer part 4 serving to space them from each other. The end of the first workpiece 14 abuts against the bars 3, which thus act as a stop for this workpiece. The end of the second workpiece 1 5 abuts against the inner surface 1 6 of the guide portion 5. The distance of each hole 8 from the plane defined by the lines of contact between the bars 3 and the first workpiece 14 is equal to the distance between the corresponding hole 6 and the undersurface 17 of the spacer part 4 against which the side surface of the second workpiece 1 5 rests.The said distances may differ for holes of different diameters so as to cater for the use of a different diameter dowel for workpieces of different depth.

In order to form the holes in the workpieces 14 and 15, a drill bit is inserted into each hole 6 and 8 of corresponding diameter and is guided thereby to form holes in the workpieces 14 and 1 5 of desired depth. The dowelling tool is then moved along the edges of the workpieces 14 and 1 5, which retain the same relative positions, and periodically stopped to permit further holes to be formed in the workpieces 14 and 15. The second member 2 can be clamped on the bars 3 in the position shown in Figure 2 by means, not shown, such as grub screws or screw threading of the bars 3 with cooperating nuts. When the desired number of holes have been formed in the workpieces 14 and 15, the tool is removed and dowels may be inserted into the holes in one of the workpieces.The other workpiece is then offered up to the dowelled part of the first workpiece and the dowels inserted into the holes thereof. The two workpieces are thus connected together by means of a dowelled butt joint.

Figure 3 illustrates another method of using the dowelling tool of Figure 1 to provide aligned holes for dowel-jointing. For this purpose, the second member 2 is provided with a portion 18 having two side surfaces 19 extending perpendicularly from an end surface 20. Each of the side surfaces 19 lines up with the inner edge of a respective one of the holes 8.

In order to convert the tool shown in Figure 1 for operation as illustrated in Figure 3, the second member 2 is slid off the bars 3 and slid back onto the bars by means of holes 21 provided for this purpose. The tool is thus arranged as in Figure 3. A plurality of holes is formed in the edge of a first workpiece 22 and each hole is provided with a respective dowel 24 (only one shown in Figure 3).

The first workpiece 22 is then laid flat on a second workpiece 23 to which it is to be connected. The dowelling tool is then placed on the other surface of the second workpiece 23 with the surface 20 disposed flat against the edge 24 of the first workpiece 22. The tool is slid along so that the side surface 19 abuts against the dowel 24. The hole 8 which is aligned with the surface 19 in contact with the dowel 24 can then be used to guide a drill bit for drilling a hole in the top surface of the second workpiece 23. This procedure is repeated for each dowel 24 and hole in the edge 25 of the workpiece 22 with the first and second workpieces remaining in the same relative dispostion.When holes corresponding to all the dowels 24 have been provided in the upper surface of the second workpiece 23, the tool is removed and the two workpieces 22 and 24 can again be connected together by means of a dowelled butt joint.

Although the operational arrangement of the tool shown in Figure 2 is more convenient for permitting dowelled joints to be formed along the edges of two workpieces to be connected together, the operative arrangement shown in Figure 3 allows the tool to be used in the formation of dowelled joints between the edge of one workpiece and a median portion of a major surface of another workpiece. The holes provided for the dowels 24 in the edge of the first workpiece 22 may be formed in any desired way.

For instance, the workpiece 22 may be arranged in the position shown by the workpiece 15 in Figure 2 with the holes 6 of the first member 1 used for guiding the drilling operations.

Figure 4 of the accompanying drawings shows another form of dowelling tool constituting another embodiment of the invention. In Figure 4, like reference numerals refer to like parts in Figures 1 to 3. These parts will not be described further and the description will therefore be restricted to the different parts of this embodiment.

The first member 1 of Figure 4 differs from that of the embodiment shown in Figure 1 in that it does not have a spacer portion 4. Instead, the guide portion 5 is provided with two projections 30 formed integrally therewith and from the other surfaces of which the bars 3 extend.

The second member 2 shown in Figure 4 differs from that shown in Figure 1 essentially only in shape.

Figure 4 illustrates the dowelling tool in use to provide holes for receiving dowels in first and second workpieces 14 and 15. Whereas the dowelling tool of Figure 1 may be used with both wooden and plastics coated boards, the tool shown in Figure 4 is intended more for use with wooden boards rather than plastics coated boards as, in certain cases, the tool would not be sufficiently reliably clamped onto the slippery plastics surfaces of such boards.

The workpieces 14 and 15, as shown in Figure 4, are disposed generally parallel to each other and in contact with each other along their adjacent surfaces. The first workpiece 14 overlaps the second workpiece 15 at its edge by the distance between the bars 3 and the rear surface of the first member 1. The first and second members 1 and 2 are clamped to the edge of the first workpiece 14 by means of wing nuts 31 (only one shown) on the bars 3, which are provided with screw threads. The workpieces 14 and 15 are clamped together, for instance by G-clamps (not shown), and are preferably also clamped to a work surface, for instance of a table or bench. The holes 6 and 8 are then used to guide a drilling tool for the formation of holes for receiving dowels.

Because the workpieces 14 and 15 are clamped together independently of the dowelling tool of Figure 4, this tool may be slid along the edges of the workpieces more easily as it is only clamped to the first workpiece 14.

Figures 5 and 6 of the accompanying drawings show a dowelling tool constituting yet another embodiment of the invention. In Figures 5 and 6, like reference numerals refer to like parts in Figures 1 to 3. These parts will not be described further and the description of this embodiment will be restricted to different parts of this embodiment.

The first member 1 shown in Figures 5 and 6 differs from that of the embodiment shown in Figure 1 in that it comprises a further portion 31 which is generally flat and coplanar with the guide portion 5, but extends from the opposite side of the spacer portion 4 to the guide portion 5. The further portion 31 has side ribs 32 to allow sliding in the second member 2, and guide ribs 33. The spacer portion 4 also has ribs 34 disposed on both its sides. In addition to the side ribs 32, further side ribs 35 are disposed along the side edges of the guide portion 5.

The second member 2 has side portions 36 which interconnects the portion of the second member provided with the holes 8 and inserts 9 with a facing clamp plate 37. The facing clamp plate 37 has formed therein a threaded bore 38 in which is screwed a clamp bolt 39. The end of the clamp bolt 39 on the side of the plate 37 nearer the holes 8 is provided with a foot 40 for clamping work pieces, whereas the other end of the bolt 39 has a head 41 which is received in a knob 42 to allow the clamp bolt to be turned by hand.

In order to essemble the tools shown in Figures 5 and 6, first member 1 is first moved in the direction of the arrow 43 so that the spacer portion 4 is pushed through notches 44 formed in the inner edges of the side portions 36. The side portions 36 are provided with inwardly facing grooves which receive the side ribs 32 and 35 of the first member 1. Thus, when the spacer portion 4 has been inserted through the notches 44, the first member 1 is moved to the right as shown in Figures 5 and 6 so that the side ribs 32 and 35 engage in these grooves. The first member 1 is thus received by the second member 2 and is slidable therein. Finally, the knob 42 is disposed over the bolt head 41 and the bolt 39 is screwed through the threaded bore 38, after which its end is provided with the foot 40.

In the embodiment shown in Figures 5 and 6, three holes 6, 8 with three inserts 7, 9 are provided in each of the first and second members 1 and 2. The axes of the holes 6 are perpendicular to and intersect the respective axes of the holes 8, and corresponding pairs of inserts has the same diameter as described with reference to Figures 1 to 3.

The portion 45 of the second member in which the holes 8 are formed is also provided with grooves 46 which receive the ribs 33 of the first member and thus provides additional guidance during sliding movement of the first member 1 in the second member 2.

In use, two workpieces which are generally flat and, for instance, comprise wood are inserted in the tool on respective sides of the spacer portion 4 with their edges abutting against the side portions 36 and against the guide portion 5 and the ribs 33. The bolt 39 is then screwed in by hand by means of the knob 42 so that the foot 40 presses the two workpieces with the spacer portion 4 therebetween against the portion 45 of the second member 2. The tool is thus firmly clamped against the two workpieces, which may then be drilled by inserting drill bits of the appropriate size through the corresponding pair of inserts 7, 9. The clamping bolt 39 may then be released and the tool slid along the edges of the workpieces to be clamped again in different positions for further drilling of the work pieces.

Claims (10)

1. A dowelling tool comprising first and second members having respective opposing parallel surfaces for receiving therebetween a first generally flat workpiece, the first member having a part or position extending substantially perpendicularly from the parallel surfaces for abutting against an edge of a second generally flat workpiece which second workpiece in use is disposed parallel to the first workpiece, the second member having at least one hole formed therein with an axis perpendicular to the parallel surfaces, and the first member having at least one hole formed therein with an axis perpendicular to the said part of portion of the first workpiece.

2. A tool as claimed in claim 1, in which the axes of the holes or of each pair of corresponding holes in the first and second members intersect.

3. A tool as claimed in claim 1 or 2, in which the first and second members are interconnected by means permitting relative movement therebetween.

4. A tool as claimed in claim 3, in which the means comprises rods fixed to one of the first and second members and passing through bores in the other of the first and second members to permit sliding movement therebetween in a direction perpendicular to the parallel surfaces.

5. A tool as claimed in claim 4, in which the rods have screwed-threaded portions provided with nuts for clamping one of or both the workpieces between the parallel surfaces.

6. A tool as claimed in claim 3, in which the means comprises side ribs formed on the first member and extending perpendicularly to the parallel surfaces, and inwardly facing grooves formed in side portions of the second member for slidingly receiving the side ribs.

7. A tool as claimed in any one of claims 3 to 6, in which the second member comprises a first portion in which the or each hole is formed, and a second portion rigidly connected to the first portion and spaced therefrom so as to be on the opposite side of the first member to the first portion, the second portion having a threaded bore which receives a clamping bolt whose axis is perpendicular to the parallel surfaces and which is arranged to clamp the first and second members to one of or both the workpieces.

8. A dowelling tool substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3 of the accompanying drawings.

9. A dowelling tool substantially as hereinbefore described with reference to and as illustrated in Figure 4 of the accompanying drawings.

10. A dowelling tool substantially as hereinbefore described with reference to and as illustrated in Figures 5 and 6 of the accompanying drawings.