THERMOPLASTIC MATERIAL

Field of the Invention

The present invention relates to the field of expanded polystyrene insulating sheathing.

Background of the Invention

Sheathing is one of the most basic and widely used applications for expanded polystyrene insulation in residential and commercial construction. It helps create an envelope around the structure, covering wall cavities and studs to increase their resistance to heat transfer and moisture penetration. With its versatility, ease of installation, and consistent performance benefits, expanded polystyrene insulating sheathing has become an industry standard. Expanded polystyrene sheathing is used in renovations as well as new constructions because of its compatibility with wood and steel framing, and masonry. Expanded polystyrene is delivered to a construction site in sheets that are sized to some purposes. Hence, many hours are still spent by the construction workers adjusting the size of some of the sheets, and there is a need for a tool that can be used for cutting the sheets at the construction site.

Object of the Invention

The objective of the present invention is to provide a tool suitable for cutting the expanded polystyrene sheets at the construction site.

Description of the Invention

A first aspect relates to a workbench for cutting sheets of an expanded

thermoplastic material comprising: - a table plate comprising a planar upper work surface for supporting a sheet of an expanded thermoplastic material; and

- a cutting device comprising a cutting bracket adapted for receiving an electrically heated cutting wire; wherein the cutting bracket is adapted for holding an electrically heated cutting wire parallel to the planar upper work surface; and wherein the planar upper work surface includes an elongate cutting slot through which the part of the cutting bracket holding the electrically heated cutting wire can pass.

The thermal cutting of the sheets of expanded thermoplastic material, such as polystyrene, involves local melting of the material with an electrically heated cutting wire conducting electrical current. The cutting wire is held by the cutting bracket, which ensures constant wire tension regardless of its temperature. In one or more embodiments, the cutting wire is connected to the cutting bracket via a spring attached to each end of the cutting wire.

In one or more embodiments, the cutting bracket is connected to a lifting means adapted for lifting the part of the cutting bracket holding the electrically heated cutting wire from a first position below the planar upper work surface through the elongate cutting slot to a second position above the planar upper work surface, and restraining it in this position.

In one or more embodiments, the cutting wire is connected to the cutting bracket via a spring attached to a first end of the cutting wire, and wherein the first end of the cutting wire is directly connected to an electrical wire adapted for conducting electricity to said cutting wire. The spring is present to absorb the elongation of the cutting wire during use, and this solution is well known within the art. Prior art cutting wire systems conduct the electricity to the cutting wire via the spring. The inventor of the present invention has found that the service life of the spring can be substantially prolonged if the cutting wire is directly connected to an electrical wire adapted for conducting electricity to said cutting wire. Furthermore, the temperature of the cutting wire increases, resulting in a cleaner cut in the expanded thermoplastic material.

In one or more embodiments, the lifting means is adapted to release its restraint of the cutting bracket, such that the part of the cutting bracket holding the electrically heated cutting wire is moved from the second position to the first position by the weight of the cutting bracket.

In one or more embodiments, the lifting means comprises a handle connected to a lift rod via a wire.

In one or more embodiments, the lifting means comprises a motor unit adapted for lifting the cutting bracket.

In one or more embodiments, the workbench further comprises lowering means for controlled lowering of the part of the cutting bracket holding the electrically heated cutting wire from the second position to the first position.

In one or more embodiments, the lowering means comprises a motor unit adapted for lowering the cutting bracket.

In one or more embodiments, the lowering means comprises a wire wheel attached to the bottom face of the table plate, a wire rollably connected to the wire wheel, and with a first end attached to the cutting bracket and a second end attached to a counterweight.

In one or more embodiments, the table plate further comprises an elongate steering element extending vertically downward from its bottom face; and wherein the cutting bracket comprises one or more wheels rollably engaged with said elongate steering element as the cutting bracket is moving up and down. In one or more embodiments, the workbench further comprises guiding means adapted for preventing the cutting bracket from horizontal movements during the movement from the second position to the first position or vice versa.

In one or more embodiments, the workbench further comprises a support frame mounted on wheels and adapted for supporting the table plate.

Another aspect relates to a cutting wire for a device for cutting expanded thermoplastic materials, said cutting wire comprising a first end and an opposite second end; wherein the first end is directly connected to an electrical wire adapted for conducting electricity to said cutting wire.

Yet another aspect relates to the use of a cutting wire for a device for cutting expanded thermoplastic materials; wherein the cutting wire comprises a first end and an opposite second end; wherein the first end is directly connected to an electrical wire adapted for conducting electricity to said cutting wire.

As used in the specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" or "approximately" one particular value and/or to "about" or "approximately" another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about", it will be understood that the particular value forms another embodiment.

It should be noted that embodiments and features described in the context of one of the aspects of the present invention also apply to the other aspects of the invention. The invention is described in more detail in the following detailed description of a preferred embodiment, with reference to the figures.

Brief description of the figures

Figure 1 is a left-side view of a workbench in accordance with various

embodiments of the invention;

Figure 2 is a right-side view of a workbench in accordance with various embodiments of the invention; and

Figure 3 is a perspective view of a workbench in accordance with various embodiments of the invention.

References

100 Workbench

1 10 Chassis

200 Table plate

210 Upper work surface

220 Cutting slot

230 Steering element

240 Pivotable support

300 Cutting bracket

310 Wheel

400 Cutting wire

500 Lifting means

510 Flandle

520 Wire

530 Lifting means

600 Lowering means 610 Wire wheel

620 Wire

630 Counterweight

Detailed Description of the Invention

Figure 1 is a left-side view of a workbench 100 for cutting sheets of an expanded thermoplastic material in accordance with various embodiments of the invention. The workbench 100 comprises a chassis 1 10 with a table plate 200, and a cutting device with a cutting bracket 300 adapted for receiving an electrically heated cutting wire 400. The cutting bracket 300 is U-shaped, and the two free ends 300A,300B are configured for receiving the electrically heated cutting wire 400. The table plate 200 comprises a planar upper work surface 210 for supporting a sheet of an expanded thermoplastic material (not shown); and an elongate cutting slot 220 through which the part of the cutting bracket 300 holding the electrically heated cutting wire 400 can pass. Here, it is the two free ends 300A,300B holding the electrically heated cutting wire 400 that are passing through the cutting slot 220 as the cutting bracket 300 is moved up and down. The position of the U-shaped cutting bracket 300 makes it adapted for holding the electrically heated cutting wire 400 parallel to the planar upper work surface 210, and to the cutting slot 220.

The cutting bracket 300 is connected to a lifting means 500 adapted for lifting the part of the cutting bracket 300 holding the electrically heated cutting wire 400 from a first position below the planar upper work surface 210 through the elongate cutting slot 220 to a second position above the planar upper work surface 210, and restraining it in this position. Figure 1 shows the second position, and Figure 2 shows the first position. As can be seen from Figure 2, the lifting means 500 comprises a handle 510 connected to a lift rod 530 via a wire 520. Wherein the lifting means 500 releases its restraint of the cutting bracket 300, i.e. the lift rod 530 is removed from the horizontal bar of the cutting bracket 300, the two free ends 300A,300B holding the electrically heated cutting wire 400 is moved from the second position, through the cutting slot 220, to the first position by the weight of the cutting bracket 300. A lowering means 600 allows for controlled lowering of the part of the cutting bracket 300 holding the

electrically heated cutting wire 400 from the second position to the first position. The lowering means 600 (Figure 2) comprises a wire wheel 610 attached to the bottom face of the table plate 200, a wire 620 rollably connected to the wire wheel 610, and with a first end attached to the cutting bracket 300 and a second end attached to a counterweight 630. When the cutting bracket 300 is in a lowered position, and the cutting wire 400 is in the first position, the

counterweight 630 is raised to a first position; and when the cutting bracket 300 is in a raised position, and the cutting wire 400 is in the second position, the counterweight 630 is lowered to a second position. This configuration allows for controlled lowering of the cutting bracket 300, as the weight of the cutting bracket 300 is at the same time lifting the counterweight 630.

The table plate 200 (Figure 1 ) further comprises an elongate steering element 230 extending vertically downward from its bottom face. The cutting bracket 300 comprises four wheels 310 (two pairs of wheels) rollably engaged with said elongate steering element 230 as the cutting bracket 300 is moving up and down. This configuration avoids looseness in the cutting bracket 300.

The table plate 200 is also shown with a pivotable support 240, i.e. an extension plate, for use when cutting large sheets of an expanded thermoplastic material.