AU744854B1 - Improved cut off saw jig - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Improved cut off saw jig The following statement is a full description of this invention, including the best method of performing it known to us: Freehills Carter Smith Beadle Me4boume~OO3855788 Printed 16 July 2001 (13:35) page 2 Freehlls Carter Smith Beadle Melboume3855788 Printed 16 July 2001 (13:35) page 2 IMPROVED CUT OFF SAW JIG Field of the Invention This invention relates to jigs adapted to assist in the use of hand tools for precision cutting purposes and in particular relates to a jig adapted for use in conjunction with an angle grinder, or like tool having a rotating cutting means, to fabricate a metal cut off saw.

Background of the Invention Metal cut off saws are dedicated sawing tools for cross cutting lengths of metal. Metal cut off saws are analogous to mitre saws used for working wood but have purpose built motors, blades and vices to cope with the requirement of working metal. Such metal cut off saws find limited application in the home handyman market and are generally purchased and used by trades specific to metal working. However, the home handyman and light general production workshop often has demand for accurate sizing of metal lengths and the currently available tools for such work, including metal cut of saws and power hacksaws are not justified.

Such users often have access to hand power tools including angle grinders.

The angle grinder is well adapted for cutting metal but in order to achieve a level of precision it is necessary to mount and control such a tool to allow suitable control and importantly suitable holding of the work to be machined.

To date, attempts have been made to provide such jigs. However, the units that are available do not have adequate vice means to safely and securely hold the work.

It would be desirable to provide a substantial, versatile and accurate jig for one with 7 to 9 inch angle grinding tools.

Statement of Invention In one aspect the invention provides an improved jig for mounting and operating an angle grinder or like tool having a rotating cutting means, including a TNB:NB:40444581.CAP 16 July 2001 rigid base I having a first blade slot 2 and a second blade slot 3 formed orthogonally to the first blade slot, a mount 4 pivotally fitted to said base for rotation about the plane of said base, said mount including a pivotable cradle 6 for holding said angle grinder or like tool and moving same between a first raised position and a second lowered position, and a vice means 8 for co-operation with said mount to hold work 9, said mount including an orthogonal fence 10 and a mitre fence 11 and said vice means including an orthogonal jaw face 12 and a mitre jaw face 13 such that rotation of said mount between said first and second positions allows said work to be held and cut at right angles or on a mitre.

Preferably, the vice includes a first jaw part 14 and a removable second part extending the purchase of said jaw when in the orthogonal cutting mode. The second part may be adapted for fitting to and extending the mitre fence component of said mount extending the purchase of said mitre fence, when in the mitre cutting mode.

Brief description of the drawings In the drawings: Figure 1 is a perspective view of the jig embodying the invention, Figure 2 is a plan view of the jig of Figure 1, Figure 3 is a sectional elevation along the line 3-3 in Figure 2, and Figure 4 is an end elevation of the jig of Figures 1 and 3.

Description of Preferred Embodiment Referring firstly to Figure 1 the cut off saw jig is shown as a plan view with a jig including a plane base member 1 formed of heavy gauge metal plating which functions as a foundation for the jig. The jig is adapted to receive a hand held 7 to 9 inch angle grinding tool T and for cradling and allowing the operation of that tool to function as a cut off saw. Accordingly, the base and associated componentry is manufactured of durable robust and heavy gauge materials to ensure the necessary robustness and rigidity required to perform accurate cutting operations.

The base 1 may be provided with adjustable feet F to allow the base to sit on or be attached to a working surface so as to ensure level and sturdy operation of the TNB:NB:40444581.CAP 16 July 2001 jig. The base is provided with a first blade slot 2 and a second blade slot 3 formed orthogonally with respect to the first. The blade slots allow the rotating blade of an angle grinder (Fig 3) to penetrate beyond the level of the base in order to effect a full and complete cut of work 9 mounted on the jig. The base 1 is provided with a rotatable mount 4 pivotally attached to the base via a mount pivot 5. The mount is formed of similar gauge material to the base and is adapted for pivotal rotation in the same plane as the base. The mount 4 includes a pivotable cradle 6 which is adapted for mounting and securely holding the portable handheld grinder (Fig. 3).

The pivoting arm of the cradle 6 is attached via an arm pivot 7 which pivots in a right angle plane to that of the mount pivot 5 therein providing a means of moving the mounted angle grinder from a first raised position with the blade clearing the blade slots and a lower position with a rotating blade moving into the slots and functioning as a cut off saw.

A principal difficulty encountered with prior art jigs of the type described above is the inability or difficulty in securely mounting work to the jig in order to allow accurate cut off operations to be accomplished, particularly cut off operations forming mitre cuts where the forces exerted on the work tend to move the work along the face of the vice means associated with such jigs. The present embodiment addresses these issues by providing a robust and dedicated vice means 8 which is adapted to co-operate with the mount means 4 to hold a piece of work 9 against one of two fences provided in the mount 4. The mount is provided with an orthogonal fence 10 and an alternative mitre fence 11. For co-operation with the fences of the mount, the vice means 8 is provided with an orthogonal face 12 and a mitre face 13.

In addition the vice means 8 is provided with a second auxiliary vice jaw second part 15 which can be removed for use when the jig is prepared for mitre cutting.

In the configuration as shown in Figure 1, the jig is set up for orthogonal or right angle cutting off of lengths of work 9 and in operation the mount 4 is secured in the position shown in Figure 1 and the vice jaw, first part 14 and second part are joined together to form a substantial extended orthogonal face 12 to the vice which co-operates with the orthogonal fence 10 of the mount 4. The tightening of vice means 8 allows a piece of work 9 to be securely located between the fence and TNB:NB:40444581.CAP 16 July 2001 the face such that the lowering of the cradle allows the rotating blade of the grinder to execute a right angle cut and penetrate into the first blade slot 2 thereby effecting an accurate and highly safe cut off operation of a length of work 9 so installed in the jig.

In the situation where a 450 or mitre cut is required from a piece of work, the mount 4 is rotated at 900 as shown in Figure 2, thereby aligning the mitre fence 11 with the mitre face 13 of the jaw vice first part 14. In order to improve the purchase and alignment area of the vice and the fence, the vice jaw second part 15 is removed and rotated about for attachment to the mount 4 thereby providing an extension of the mitre fence 11 such that the operation of the vice means 8 provides a secure and rigid mounting of the work 9 to the jig for a mitre cut operation. In a similar manner to the orthogonal arrangement of the jig, the cradle 6 is then lowered down onto the work 9 and the rotating blade penetrates the work and enters the second blade slot 3 thereby effecting a full cut of the work 9 in a mitre cut.

The various features of the improved cut off saw jig provide for the first time a robust safe and highly accurate tool for effecting cut off operations utilising readily available hand tools without the need to purchase costly dedicated tooling.

In most respects the improved cut off saw jig of the invention provides superior performance to all currently available jigs adapted for retro-fitting of hand tools and also provides superior performance to many entry level dedicated cut off machines.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described.

It will be understood that the present invention encompasses all such variations and modifications that fall within the spirit and scope.

TNB:NB:40444581.CAP 16 July 2001

Claims (4)

1. An improved jig for mounting and operating an angle grinder or like tool having a rotating cutting means, including a rigid base having a first blade slot and a second blade slot formed orthogonally to the first blade slot, a mount pivotally fitted to said base for rotation about the plane of said base, said mount including a pivotable cradle for holding said angle grinder or like tool and moving same between a first raised position and a second lowered position, and a vice means for co-operation with said mount to hold work, said mount including an orthogonal fence and a mitre fence and said vice means including an orthogonal jaw face and a mitre jaw face such that rotation of said mount between said first and second positions allows said work to be held and cut at right angles or on a mitre.

2. The jig of claim 1, where the use includes a first jaw part and a removable second part extending the purchase of said jaw when in the orthogonal cutting mode.

3. The jig of claim 1 or 2, wherein the second part is adapted for fitting to and extending the mitre fence component of said mount extending the purchase of said mitre fence, when in the mitre cutting mode.

4. A cut off saw jig substantially as discussed with reference to the accompanying drawings. DATED: 16 July 2001 FREEHILLS CARTER SMITH BEADLE Patent Attorneys for the Applicant: GLEN HEWSTONE TNB:NB:4044458 I.CAP 16 July 2001