AU4459099A

AU4459099A - Circle cutter Attachment

Info

Publication number: AU4459099A
Application number: AU44590/99A
Authority: AU
Inventors: Quenton SEED
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-08-20
Filing date: 1999-08-20
Publication date: 2000-03-09

Description

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AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT CIRCLE CUTTER ATTACHMENT The following statement is a full description of this invention, including the best method of performing it known to me: Circle Cutter Attachment.

This invention relates to improvements in attachments for circle cutting with oxy- acetylene cutting torches.

Many types of circle cutters have been proposed however, it has been found that the use of a guide wheel whether fixed or slideably attached may offer an obstruction when cutting circular plates from sheet steel, where the surface of the sheet to be cut is uneven, so as not to allow the guide wheel to rotate freely, resulting in an unsatisfactory cut and wastage of material. In relation to the prior art it has also been found that when the head of the cutting torch is used as a mounting means complete removal from the torch is required after use for normal operation to proceed. It has also been found there is a degree of difficulty in accurately setting the attachments for the required circle radius as the distance from the center of the cutting torch head to the pivot point has to be measured and reset for every change in circle size.

These problems are overcome by this invention, which provides a circle cutter comprising a slide frame assembly, incorporating a measuring scale (permanently fixed to the body of the cutting torch), a mounting means which is fully slideable along the extent of the slide frame, a vertically adjustable pivot rod (having a compass point) fixed to the mounting means.

The necessity for a guide wheel is eliminated by the pivot point being attached to the cutting torch. The operator guides the handpiece around the pivot point keeping the head of the torch at the required height. To set the circle radius the pivot rod is moved along the slide frame by adjusting the mounting means while the corresponding circle radius is indicated at the front face. This attachment eliminates the need for measuring the distance from the center of the cutting torch head to the compass point to calculate the circle radius thus enormously increasing efficiency.

In one form of the invention a U shaped slide frame assembly is formed to fit over the rigid conduit of the cutting torch so as to provide a support for a mounting means, said assembly is adapted to carry engravings marking the frame off in integers. The U shaped slide frame is attached through the rigid conduit with a releasable locking means such as counter sunk screws.

~_l--lll lil~I- I~ ~1I111 11 1 1 1 1 I I Il A mounting means is slideably attached to the U shaped frame being fully slideable along its limits. The said mounting means is formed to fit over the slide frame, having a shoulder on the lower side, adjacent to and parallel with the body of the cutting torch as a means of locating it to the slide frame. A locking means on the upper surface such as thumb screws are used to lock the mounting means at the appropriate position. A threaded nut is suitably fixed to the lower face of said mounting means where a vertically adjustable pivot rod is attached, said pivot rod is threaded to engage the threaded nut, a compass point is formed on the opposite end.

Reference may now be made to a preferred embodiment of the invention as shown in the attached drawings.

Fig. 1 Shows one example of the improved circle cutter attachment according to this invention.

Fig. 2 Shows a cross sectional view of the attachment when fastened to a conventional cutting torch.

Fig. 3 Shows the circle cutting attachment when fitted to a conventional cutting torch.

Fig. 4 Shows a view of the back of the attachment when fitted to a conventional cutting torch.

Fig. 5 Shows the improved circle cutter fitted to a conventional cutting torch with the mounting means inverted and locked in place to permit normal operation of the torch to proceed.

Referring to figure 1, it can be seen that the improved circle cutter according to this invention comprises a U shaped slide frame(8) with scale attached(6) fixed to the body of the cutting torch through the center of the rigid conduits(9) with counter sunk screws(7).

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Mounting means(5) with pivot rod(10) attached, is fully sliceable along frame(8), and is locked at the required position with thumb screws(4), the front face(12) of the mounting means indicates the changing circle radius as it's position on the slide frame is changed.

Figure five shows the attachment in the stored position, the thumb screws have been loosened and the mounting means(5) has been removed from the slide frame(8) inverted and refitted. In this position the attachment does not interfere with the normal operation of the torch.

Claims

1. A circle cutter attachment having a frame formed to fit over the rigid conduits of the cutting torch incorporating an attached scale which marks the frame off in intergers. To this frame is fixed a slideable mounting means, suitably attached to said mounting means is a radius rod with a compass point formed on the end. The handpiece can be rot- ated around the compass point to allow circles to be cut from sheet steel without the use of a guidewheel. As said mounting means is moved along the frame the circle radius is displayed at the front face of the mounting means.

2. A circle cutter attachment substantially as herein described with refe- rence to the accompanying drawings. QUENTON SEED. 19/8/1999.