FIELD OF THE INVENTION:

This invention relates to a snow shovel. The technology field, in which this invention can be classified according to the international patent classification, is E01H5/02 - Hand implements for removing snow or ice from roads or like surfaces.

TECHNICAL PROBLEM

It is a common knowledge that shovels used for snow removal are made of plastic, wood, aluminium and other metals or combinations of these materials. The problem with such materials is their rough surface which causes friction between snow and the material the shovel is made of, which results in snow sticking to the shovel. This makes the shovel heavier which reduces work efficiency and, in order to maintain the desired level of efficiency, it is necessary to frequently stop and clean the shovel. The problem has so far been tackled by spraying a thin layer of PTFE (Polytetrafluoroethylene) on the upper side of the shovel, but without any significant success because PTFE applied in such a way to a shovel surface peels off after some time and it is impossible to ensure sufficiently clean shovel surface and adhesion to apply PTFE to. Another possible solution is that a PTFE foil is glued to the material the shovel is made of. Efforts made with this procedure have not produced any results because PTFE foil either breaks during forming of the shovel body, or form cavities due to the different coefficients of the PTFE foil and the material(s) it is glued on.

Another existing problem is how to make a lighter and stronger snow shovel because it has been confirmed that plastic shovels, which are lighter than the metal ones, break very quickly. This invention will primarily resolve the problem of designing a shovel body with PTFE foil. Another problem this invention resolves is the design of a lighter and stronger shovel body. This invention brings savings on the quantity of aluminium because a layer of PTFE on an aluminium plate glued with a 2-part glue ensures the structural strength of such a shovel in addition to specially designed grooves. Savings in the amount of aluminium used to make snow shovels can be up to 50% because the thickness of plates used to make a shovel can be only 1 mm and these shovels will still be as strong and sturdy as those made of traditional 2 mm aluminium plates.

PRIOR ART

The inventor is not familiar with any patent relating to a snow shovel designed as a combination of base materials (e.g. a metal plate with an upper part designed in PTFE foil). Solutions to the problem were sought by coating metal snow shovels with wax but these were short-lived. There are on the market products with PTFE solution bottled under the pressure which is sprayed onto the shovel surface, but the effects during use last for a short time and the PTFE solution has to be applied several times. Efforts were made to enamel the shovel surface, but a snow shovel is often abraded against a hard surface (asphalt, concrete) and such impacts result in damage to the enamel. A search of PATENTOSCOPE, USPTO and ESPACENET patent databases did not reveal any similar registered or patent-pending applications.

BRIEF SUMMARY OF THE PRESENT INVENTION:

The primary objective of the invention is to design a snow shovel whose upper surface is protected with a PTFE material to prevent snow sticking to the shovel surface. The design has been developed by primarily creating a strong and stable bond between the PTFE foil and the bearing surface of the shovel body, i.e. the aluminium plate. This bond is achieved with the aluminium plate whose upper surface to which the PTFE foil is to be glued is previously ground to be rough enough for application of a 2-part adhesive. After that the surface is air-blasted to remove any dirt. The PTFE foil is also air-blasted (cleaned) to remove dirt. Then a thin layer of 2- part adhesive is applied on both the PTFE foil and the aluminium plate. Finally the PTFE foil and the aluminium foil are clamped together.

This sandwich panel, made of the aluminium plate and PTFE foil, is then cut to smaller pieces and formed into a shovel. The best cut is achieved by the use of power shear machine. This piece is then formed in a press which moulds the shovel body. Depending of the design of the body, for example if a deeper form is desired to receive more snow, grooves have to be made on the shovel body which will receive all extra building material necessary on the curves to prevent the foil from breaking. Simple shovel forms do not require this, because there are no significant deformities or elongated material. To protect the front part of the shovel, which is abraded on surfaces from which snow is removed (typically asphalt or concrete), it is recommended that the leading edge of the shovel is protected with a stainless steel shield.

The secondary objective is to ensure savings in the quantities of aluminium used to make snow shovels by substituting part of the aluminium with PTFE material which reduces the quantity of aluminium used by 50%. A shovel made this way retains all the features of an aluminium shovel on one hand but on the other hand it is improved because snow and ice do not stick onto it.

an aluminium shovel. This is due to the PTFE being lighter than aluminium (its specific density is around 1.100,00 kg/m ³ compared to the specific density of aluminium which is 2.700,00 kg/m ³ ), which enables production of a shovel that is 50% lighter than the one made of aluminium. Using a lighter shovel the person removing the snow will get less tired. Another important feature of this invention is its design with lateral and bottom grooves whose function is to solidify the aluminium plate, which allow the shovel to be made of a PTFE foil and an aluminium plate which is only 1.0 mm thick.

BRIEF DESCRIPTION OF THE DRAWINGS:

The enclosed images, which are referred to in the description and which form a part of the description, illustrate the best invention embodiment so far and help explain the basic principles of the invention.

Figure 1 - View of the snow shovel laminated with PTFE material

Figure 2 - Side view of the snow shovel laminated with PTFE material

A LIST OF REFERENCE SIGNS USED IN THE DRAWINGS

1. PTFE Foil

2. Aluminium sheet

3. Shield

4. Handle

5. Torban screw

6. Nut

7. Shovel handle holder

8. Grooves (Ripples)

DETAILED DESCRIPTION OF AT LEAST ONE WAY OF CARRYING OUT THE INVENTION

A typical embodiment of a snow shovel includes gluing of a 0.5 mm thick PTFE foil (1) size 1 x 2 metres, onto a 1.5 mm thick aluminium sheet (2) (EN AW5754) of the same size using a 2-part adhesive. Before gluing, the upper side of the aluminium sheet onto which the glue is applied has to be ground to create a surface rough enough to apply glue. Grinding is preferably performed on a surface grinder. The entire sheet is then air-blasted with compressed air of 400 kPa or higher to remove all particles which remain after grinding. The PFTE foil which will be glued onto the aluminium sheet is first cut to size which is slightly larger than the sheet, the surface on which the glue will be applied is air-blasted with compressed air of 400 kPa or higher and is then placed on a flat surface. Using a roller, a thin coating of 2-part adhesive is applied on the foil. Simultaneously, a thin coating of 2-part adhesive is applied onto the aluminium sheet. When enough time has passed according to instructions provided by the adhesive manufacturer, the PTFE foil is placed on the aluminium sheet and the 'sandwich' is pressed under min. 1 MPa.

After the pressing is completed, the plate is cut into pieces used for shaping a preferred size of a shovel (50 x 50 cm). The cut piece is inserted into a press equipped with a shovel moulding tool. In the preferred embodiment the shovel forming tool also makes grooves (ripples) (8) in the places in which, during the shaping of the shovel, excess material builds up. The function of these ripples (8) is not only to take over any surplus material but also to ensure functional reinforcement of the shovel itself. In a preferred embodiment the grooves (ripples) (8) are made on the underside of the shovel, 2 grooves of approx. 10 cm each, 10 cm apart, 5 mm high and a shovel handle holder (7) is also formed here. In a preferred embodiment grooves (ripples) (8) are also made at the sides and at the back of a curved part of the shovel, i.e. three 4 cm coned grooves with 1 cm starting width and four grooves at each half of the rear side of the shovel, each 6 cm long and with 1 cm starting width.

When the shovel is formed, five 8 mm holes are drilled on the end which comes in contact with the ground surface used to fix the shield (3) preferably made of 0.8 mm V-shaped stainless steel which will protect the snow shovel from impact or wear when used on hard surfaces. On the part where the handle holder is designed, two 6 mm holes are drilled which are used to install the shovel handle using two Torban screws (5) and M6 nuts (6).

In a preferred embodiment the shovel has a wooden handle (4). Another embodiment of a shovel has a handle (4) made of 30 mm hollow aluminium tube with a polyamide holder on the top.

Another possible embodiment uses a sheet made of metal alloys instead of aluminium.