Technical field

The invention relates to a snow removal apparatus for preventing snow accumulated on a roof structure from adhering to the roof surface. Background art

A major problem is posed by snow accumulating on roof structures in winter, as well as by snow falling from roof structures during the spring melt.

In case of heavier or extended snowfalls a larger amount of snow may accumulate on roof structures and may last for a prolonged period of time under lower-temperature conditions. In specific cases the accumulated snow may get compacted into ice slabs.

Snow accumulated on roof structures in large amounts may eventually cause damage to the roof, and is thus a serious issue. The problem posed by snow accumulated on roof structures is especially serious during snow melt, when larger slabs of snow or ice may fall from the roof.

Snow guard and snow fence designs currently applied only provide limited safety.

A number of different arrangements have been offered for preventing snow from adhering to roof structures.

The document with publication number JP 2001-040833 discloses a heating apparatus that operates as an electric heating apparatus, has a fixed configuration, and is secured to the roof surface.

Patent specification JP 7-119335 discloses a solution wherein a heating wire is disposed on the roof such that the wire is set perpendicular to the principal axis of the roofing tiles at the locations where the neighbouring tiles meet.

These known arrangements have the common disadvantage that their operation is not dependent on the amount of snow fallen on the roof. Patent specification JP-149031 discloses an arrangement comprising a control system based on weight sensing that is adapted to operate the thawing mechanism. However, the specification does not describe the configuration of the thawing mechanism, and the patent also has the disadvantage of being structurally complex.

The document with publication number KR 2009-040833 discloses a heating apparatus disposed on a roof structure below the individual roofing tiles. The disadvantage of the solution is that it is overly complex and costly. Disclosure of invention

The objective of the present invention is to provide a snow removal apparatus that eliminates the drawbacks of known solutions, prevents snow fallen on the roof from adhering to the roof surface in a simple manner, its operation is dependent on the amount of snow accumulated on the roof, and it is easy to install on existing roof structures.

The objective of the invention is fulfilled by providing a snow removal apparatus that is characterised by that it comprises a mesh structure stretched between two tensioning elements secured to the outer surface of the roof structure with securing elements, weight sensors disposed on the mesh structure, and a switching element or switching elements, where the switching elements are connected to a power source through a transformer and are operated by the weight sensors.

In a preferred embodiment of the snow removal apparatus according to the invention the mesh disposed between the tensioning elements has a modular configuration.

Brief description of drawings

A preferred embodiment of the snow removal apparatus according to the present invention will be described in detail below, referring to the attached figures where

Fig. 1 shows the schematic view of the snow removal apparatus according to the invention, and Fig. 2 shows the schematics of a heating system applied for the snow removal apparatus according to the invention.

Best mode of carrying out the invention

The snow removal apparatus according to the invention is implemented as a mesh structure 4 disposed between two tensioning elements 2, 3, the mesh structure 4 being made from a material having good heat conductivity.

The snow removal apparatus according to the invention is disposed on the outer surface of the roof structure 9 of a building, stretched between the tensioning elements 2, 3 such that it is secured to the roof at multiple locations with securing elements 5.

Sensor 6 elements are disposed on the mesh structure 4 at a predetermined distance from one another. The sensor 6 elements are connected to a switching element 7 in a manner known per se, and are adapted to actuate the switching element 7 when the presence of a predetermined amount of snow is detected on the roof structure.

The switching element 7 is connected to the electric network through a transformer 12 . The transformer is adapted to reduce the 220 V voltage of the electric network to 12 V or 24 V.

Fig. 2 shows the schematics of the heating system applied for the snow removal apparatus according to the invention. The sensor 6 of the inventive apparatus (the sensor 6 being implemented as a weight sensor switch 17) is fitted with a timer relay 16, and is connected in parallel with a temperature sensor 14 that is fitted with a switch 15.

The apparatus itself is connected to the power source 10 that is in connection with the electric network. The output voltage of the power source

10 is converted to low voltage applying a transformer 12.

The low-voltage current is utilised to heat the mesh structure 4 of the snow removal apparatus. A heating wire 13 is applied for heating the apparatus. The heating wire 13 is turned on by a switching element 7 operated by a temperature sensor 14 and a weight sensor switch 17. As the mesh structure 4 is heated up, snow falling on the roof structure begins to melt, with meltwater being guided to the gutter 8 and then drained off.

Due to continued melting of the snow the weight sensor switch 17 becomes released, thereby breaking the connection between the weight sensor 6 and the switching element 7.

The switching element 7 switches off the transformer 12, causing the mesh structure 4 to stop heating. When the snow begins to fall again, the above described process is repeated as initiated by the signal of the weight sensor 6.

Thereby, snow can be prevented from accumulating on the roof structure in an amount that may be dangerous, and it may also be provided that larger snow or ice slabs do not fall from the roof during the natural melting process, thus protecting people standing under the roof edge from the danger of injuries caused by falling snow or ice slabs. The snow removal apparatus comprises a main switch 11 that may be utilised for entirely cutting off power to the apparatus to prevent the accidental actuation of the weight sensor during snowless periods.

The snow removal apparatus has the advantage that it may be installed on any type of roof structure even as a retrofit, in any surface size, and in a modular configuration.

Since the amount of electric power consumed during snow removal is low, the apparatus may be operated economically.

With the application the apparatus according to the present invention the dangers associated with melting snow may be averted and snow removal costs may be minimized. List of reference numerals

1 snow removal apparatus

2 tensioning element

3 tensioning element

4 mesh structure

5 securing element

6 sensor

7 switching element

8 gutter

9 roof structure

10 power source

11 main switch

12 transformer

13 heating wire

14 (temperature) sensor

15 switch

16 timer relay

17 weight sensor switch