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Title:
THERMAL STYROFOAM CUTTER
Document Type and Number:
WIPO Patent Application WO/2012/138240
Kind Code:
A1
Abstract:
Subject of the invention is the thermal cutter for Styrofoam allowing easy cutting of Styrofoam shapes, intended for use in construction. Thermal Styrofoam cutter composed of a holder with an embedded guide strip with the gap (2) along most of its length, in which flat insulation elements (3) are fixed, which partially protrude outside the outline of the guide strip (1). The edges of the insulation elements (3) protruding outside the outline of the guide strip (1) are surrounded with the heating element (4), the first end of which is connected to the guide strip (1), and the other end of the heating element (4) is joined with the tensioning unit (5) located in the sleeve (6), made of insulating material resistant to high temperature. To the tensioning unit (5) and guide strip (1) cables supplying electric power are connected.

Inventors:
DZIEZA ZBIGNIEW (PL)
MISKOWIEC JACEK (PL)
KRAWCZUK KRZYSZTOF
Application Number:
PCT/PL2012/000023
Publication Date:
October 11, 2012
Filing Date:
April 05, 2012
Export Citation:
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Assignee:
DZIEZA ZBIGNIEW (PL)
MISKOWIEC JACEK (PL)
KRAWCZUK JAKUB (PL)
KRAWCZUK SLAWOMIRA (PL)
KRAWCZUK DOMINIKA (PL)
International Classes:
B26B27/00; B26D3/00; B26F3/08
Foreign References:
JP2010221379A2010-10-07
KR20050013886A2005-02-05
US6230603B12001-05-15
PL383132A12009-02-16
Attorney, Agent or Firm:
MAGOŃSKA, Alina (31-416 Kraków, PL)
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Claims:
Patent Claims

1.

Thermal Styrofoam cutter composed of a holder with an embedded guide strip characterised in that in the holder the guide strip (1) is embedded, with the gap (2) along most of its length, in which insulation elements (3) are fixed, which partially protrude outside the outline of the guide strip (1), whereby the edges of the insulation elements (3) protruding outside the outline of the guide strip (1 ) are surrounded with the heating element (4), the first end of which is connected to the guide strip (1), and the other end of the heating element (4) is joined with the tensioning unit (5) located in the sleeve (6), made of insulating material resistant to high temperature, and furthermore, to the tensioning unit (5) and guide strip (1 ) cables supplying electric power are connected.

2.

The thermal cutter according to Claim 1 , characterised in that it has the heating element (4) made of resistive tape profiled favourably in such a manner that the cross section of the heating element (4) is close in shape to the letter U.

3.

The thermal cutter according to Claim 1 , characterised in that the insulation elements (3) are favourably made of ceramic material.

4.

The thermal cutter according to Claim 1 , characterised in that the heating element (4) can move in relation to the guide strip (1) at the majority of its length.

Description:
Thermal Styrofoam Cutter

Subject of the invention is the thermal cutter for Styrofoam allowing easy cutting of Styrofoam shapes, intended for use in construction.

Cutting polystyrene blocks during construction works with typical tools such as toothed saws, due to pearl-like structure of the material, causes great contamination of the surrounding area, and also the environment, since the material waste from mechanical cutting is easily moved by wind and spread in large areas. Collecting of the spread material, particularly in open spaces, with vacuum cleaners is a laborious and costly activity.

This problem can be avoided with the thermal cutting of Styrofoam blocks. Thermal cutting of Styrofoam involves local melting of the material with a heated wire conducting electrical current. The cutting wire is usually held by a frame, which ensures constant wire tension regardless of its temperature.

Device for wire cutting and forming of Styrofoam blocks is known under the Polish patent application no. 383132. The device comprises, among others, a frame for horizontal cutting, with two movable swinging wings with electrically heated cutting wires spanned between them.

Portable Styrofoam cutters manufactured by Prometal System is known. It comprises a cutting arm supporting tensioned cutting wire, connected with a cable to the power supply device.

Also portable thermal Styrofoam cutter is known, sold as Styro-Cut, with a flat heating strip with an incision over almost the entire length, which allows connection of power supply to the heating element from one side only. Relatively high temperature of the working part of the tool causes significant expansion of the heated cutting part. Since, in case of the heating strip, only the front part of the tool comes into contact with the material being worked, to which it transfers the heat, the other half of the strip is heated to a higher temperature, which causes its deformation. Another drawback is the relatively high heat capacity of the heating part, resulting from the dimensions of the heating strip. This results in both longer heating and cooling of the device and leads to undesired loss of energy. On the other hand, wire cutters with low thermal capacity, require a tensioning frame and, therefore are not recommended for portable solutions. The tensioning frame with usually large dimensions reduces operator's free space, especially when cutting large parts.

The device included in the invention has no such drawbacks.

The substance of the invention is a thermal Styrofoam cutter provided with a holder with a guide strip embedded in it, which - at a considerable part of its length - has a gap in which flat insulation elements are fixed, which partially protrude outside the guide strip. The edges of the insulation elements, protruding outside the outline of the guide strip, are surrounded with a heating element, the first end of which is connected to a tensioning unit placed in a sleeve made of insulating material, resistant to high temperature and, furthermore, to the tensioning unit and guide strip cables are connected which supply electric power. The thermal cutter has the heating element made of resistive tape profiled in such a manner that the cross section of the heating element is close in shape to the letter U. Insulation elements are made of ceramic material which is an advantage.

The heating element at most of its length can move in relation to the guide strip.

An example of the subject of invention version is shown in a drawing, in which fig. 1 shows the general view of the thermal Styrofoam cutter, and fig. 2 shows an expanded cross sectional view of the working part of the cutter.

In the example shown, the guide strip 1 is made of three stainless steel parts, joined together with fusion welding. As the central part is narrower, after joining, the guide strip 1 has a recess 2 at the major part of its length, in which plates made of aluminium oxide ceramics 96 % Al 2 0 3 are made. The dimensions of the ceramic plates are selected in such a manner that the plates partially protrude outside the outline of the guide strip 1. Parts of the ceramic plates 3 protruding outside the outline of the guide strip 1 support the metallic frame 4, which serves as a thermal cutting element. The metallic tape 4 is shaped along its entire length in the form of U letter and embraces the protruding edges of the ceramic plates 3. The beginning of the metallic tape 4 embraces the protruding part of the central part of the guide strip 1 and is permanently joined to it, and the other part of the metallic tape 4 is joined with the tensioning device made of a tensioning pin 5 seated in the sleeve 6 and tensioning spring 8. The thermal cutting element is supplied with low voltage, directly from a safety transformer. The supply conductors are lead directly to the guide strip 1 , which is joined with the first end of the thermal cutting element and the tensioning pin 5, which is connected to the other end of the thermal cutting element. Due to high currents in the heating circuit, the electrical breaker is installed at the high voltage side.

In the device according to the invention, thanks to the aluminium oxide plates, constant position of the thermal cutting element is ensured, which does not move even at high pressure of the tool. The tensioning system, in turn, prevents from deformation of the thermal cutting element at high temperatures. Ceramic plates prevent also from overheating of the thermal cutting element, especially those parts which have no direct contact with the material being worked. Moderate thermal conductivity of aluminium oxide ceramics of 25 W/(m*K) allows considerable temperature gradient between the hot cutting element and the guide strip. On the other hand, due to low thermal capacity of the cutting element (metallic tape), the ceramic plates allow relatively fast cooling of the thermal cutting element after disconnecting the power supply. Those advantages increase the operational safety level.