CA2978278A1

CA2978278A1 - Plastic pipe cutter

Info

Publication number: CA2978278A1
Application number: CA2978278A
Authority: CA
Inventors: Khoja E.K. Fatehally
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-09-01
Filing date: 2017-09-01
Publication date: 2019-03-01

Abstract

The invention relates to a manually operated tool for cutting plastic pipes such as ABS and the tool can now be made by injection moulding from plastic or aluminum. The pipe to be cut is inserted in a hole in the tool, a blade is brought down at right angles to the axis of the pipe and a cut is made by repeated turning of the handle of the tool around the pipe.

Description

DESCRIPTION
This invention pertains to a manually operated tool for cutting plastic pipe such as ABS.
An existing roller type of cutting device used for cutting copper pipes and tubes cannot be used for cutting plastic pipe. It employs the principle of compressive yielding which the copper tube or pipe is able to accommodate. Plastic pipes, including ABS pipe, do not remain rigid and 'squash-up' when subjected to cutting by such a tool, rendering inaccurate, difficult, and time-consuming cuts. Another type of plastic pipe cutting tool employs a pawl and ratchet arrangement which mechanism provides stepwise incremental motion of the blade. The tube or plastic pipe is inserted into an open-ended slot (much like an open-ended wrench). The blade, ejected incrementally from inside one jaw, presses against the tube or pipe until the tube or pipe is cut, when the blade butts against the opposite jaw. This device accommodates a maximum 1 1/2 inches outside diameter of pipe. It is ideal for cutting flexible hose and the like; however, it tends to squash and possibly crack plastic pipe, which deformation or damage is a definite setback when assembling standard plastic pipe fittings to the cut pipe, in piping installations. The common practice therefore is to cut the plastic pipe with a wood-cutting saw or metal-cutting saw. These methods result in a rough and irregular cut which is also not perpendicular to the axis of the pipe. This makes it very difficult and time-consuming when these pipes are used with standard ABS fittings such as tees, elbows, couplings, etc. The rough pipe cut has to be trimmed and deburred with sandpaper etc. before a glued joint can be made with a fitting.
I have found that these disadvantages and problems can be completely eradicated by providing a controlled cutting action by a smooth high tensile steel knife-edge blade on the pipe as opposed to the compressive yielding principle employed by other devices. This results in the pipe being cut to the exact length required; the cut is clean, no deburring is required and the cut is square to the axis of the pipe.
There is no material wastage in the form of 'saw dust' and trimming. The device, thereby, allows for maximum time efficiencies in the pipe cutting function. All parts are easily assembled and the blade can be replaced when worn.

DRAWINGS
In the drawings which illustrate the embodiments of the invention Fig. 1 is an elevation partly in section. Fig. 2 is a top view of this embodiment. Fig. 3 is the sub-assembly of the screw with wing nut and pin. Fig. 4 is the blade and Fig. 5 is a bushing for cutting a different size of pipe.
The tool illustrated comprises a body (1) with a slot (2) in it, in which a knife-edge blade (3) is guided and caused to slide perpendicularly to the hole (4).
The pipe to be cut is inserted into this hole. A second smaller hole aligned with the slot forms a guide for the screw (7).
The blade (3) also shown separately in Fig. 4 has a slot at each end. One end of the blade is hinged by means of the slot in it onto a pin (5) which is fixed in the body of the tool. The pin is a standard slit spring-pin and is held by spring action in a third hole in the body of the tool. The other end of the blade is hinged onto a pin (6) at one end of the adjusting screw (7). The other end of the adjusting screw has a wing nut or equivalent (8). Tightening this wing nut brings the blade to bear down on the plastic pipe. The adjusting screw slides freely in its guide hole in the body of the tool.
The tool is operated by inserting the pipe into the hole (4) to the extent required and bringing the blade to bear down on the pipe by means of tightening the wing nut or equivalent. The tool is then rotated around the pipe a full turn or two and the wing nut further tightened. The tool is again rotated around the pipe and the procedure repeated until the pipe has been cut.
The embodiment shown in Fig. 5 is a bushing adapter shown in two views which slides into the hole (4) of the main body (1) of the tool and has a provision for proper locating. This bushing enables a different diameter of pipe to be cut.
The locating is accomplished by short groove (9) in the hole (4) of the main body of the tool and a ridge (10) on the outside of the bushing.
The idea may also be put into operation in a power-driven tool.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. The slot 2 in the body of the tool is now modified so that it can be machined by an appropriate milling cutter and the need to provide a 'spacer' in the injection mould is eliminated, thus reducing mould and manufacturing costs.

2. The handle part of the body of the tool has been modified by including an opening to reduce cost of manufacturing and provides the convenience of storage by hanging the tool on a hook in the workshop.

3. The immediate bearing area under the wingnut on the body of the tool is now 'spot' machined to allow easy turning of the wingnut and also reduce undue wear.

4. The bushing adaptor is modified by eliminating the locking feature since when properly located and the blade is brought down into the slot, axial movement of the bushing cannot occur.