WO2007129353A1

WO2007129353A1 - System used to fix concrete counterweights on the outside of tanks for washers, washer/dryer combos and similar appliances.

Info

Publication number: WO2007129353A1
Application number: PCT/IT2007/000321
Authority: WO
Inventors: Simone Pardini; Gianluca Ferro; Marco Del Buon Tromboni; Giovanni Zambon
Original assignee: Meccanica Generale S.R.L.; SALES MANAGEMENT S.A.S. DI MARCO MICHELE DEl BUON TROMBONI & C.
Priority date: 2006-05-04
Filing date: 2007-05-02
Publication date: 2007-11-15
Also published as: ITMC20060053A1

Abstract

The present invention relates to a system used to fix concrete counterweights on the outside of tanks for washers, washer/dryer combos and similar appliances, characterised by the fact that it provides the following sequence of operations: - moulding of a plastic insert (1, 100) composed of a plate (Ia, 100a) that incorporates one or more legs (Ib) towards the inside; - inclusion of the said insert inside a mould used to form the concrete counterweight in such a way that, once forming is completed, the legs are deeply incorporated into the mass of the counterweight (10) and the plate (Ia) shortly protrudes from the rear side (10a) of the plate of the counterweight; - fixing of the plate of the counterweight against a suitable point of the tank (20)through the interposition of a adhesive layer (30, 300).

Description

System used to fix concrete counterweights on the outside of tanks for washers, washer/dryer combos and similar appliances.

The present patent application relates to a system used to fix concrete counterweights on the outside of tanks for washers, washer/dryer combos and similar appliances.

As it is known, tanks of washers and similar household appliances must be provided with counterweights in order to reduce the vibrations imposed by the vortical rotations of the drums they contain during spinning.

In particular, the tanks used by the said household appliances are made of plastic materials (normally polypropylene) and the counterweights mounted on the outside of the tanks are generally formed from concrete, in order to be given a shape that exactly matches the external profile of the tanks.

This mutual fixing has been so far obtained by means of suitable connection screws; it being provided, in particular, that the screws are inserted in through holes drilled on the concrete structure of the counterweight, and then screwed into corresponding housings on the tank.

Alternatively, fixing is obtained with a sort of radial belt that is used to "tie" the counterweight to the corresponding tank.

A careful examination of the reference technology has shown that the aforementioned methods used for counterweight fixing are not fully satisfactory.

As a matter of fact, the operations that are necessary to drill the through holes for the insertion of screws are technically complicated and expensive; the same is true for the operations that are necessary to provide the same holes with bushings, washers or other means designed to cooperate with the screws.

Moreover, similar inconveniences are experienced with reference to the operations that are necessary to provide the plastic structure of the tank with the threaded housings designed to receive the said screws.

Furthermore, the need to provide the structure of each counterweight with through holes imposes a high specific weight of the counterweight in order to recover the concrete mass removed from the "core" of the structure. To that end, a specific concrete mix must be provided with considerable costs.

The specific purpose of the present invention is to devise an alternative system to fix the said counterweights on the outside of the polypropylene tank. In particular, according to the new system, each counterweight is directly adhered against the external wall of the tank, based on an adhesion technique that provides for the application of a suitable adhesive layer between two surfaces that have been previously subjected to a physical- chemical activation process. With an illustrative, not limitative purpose, a similar physical-chemical activation of the surfaces to be adhered can be obtained by alternatively using the so-called "atmospheric plasma", "crown", "flame (methane)" or "UV- Ozone" techniques.

This avoids the use of "external" connection means between the tank and the counterweights, and more precisely the use of the screws that are the most popular fixing means according to the prior technique.

However, the aforementioned adhesion technique can be advantageously used only to make two plastic surfaces adhere permanently, and not in the case of adhesion of a plastic surface (such as a washer tank) and a concrete structure (such as a counterweight).

The specific solution that has made it possible to use the atmospheric plasma technology also for the aforementioned purpose consists in the fact that a special plastic insert, which is basically shaped as an "upturned stool", is incorporated in each counterweight during forming. Due to the special configuration, the upward legs of the said "tool- shaped" structure engage deeply and irreversibly into the concrete mass of the counterweight, while the seat of the said "tool-shaped" structure briefly emerges from the rear surface of the counterweight.

It can be otherwise said that the side facing the installation tank of the counterweight is provided with a sort of plastic plate surrounded by the concrete mass. The presence of the plastic surface in lower position on the counterweight allows to apply the adhesion technology to guarantee the mutual permanent adhesion between the rear wall of the counterweight and the external wall of the tank.

The two plastic surfaces (counterweight and tank) adhere thanks to the presence of an intermediate adhesive layer that is applied after the two surfaces are treated with the physical-chemical activation process that is typical of the aforementioned technologies.

This general description has shown the specific advantages of the new fixing system with respect to the aforementioned prior technique. The first advantage consists in the elimination of the screws, which are more expensive than the quantity of adhesive agent required by the system of the invention, and in the elimination of the screw housings on the tank.

Moreover, the useful volume of each counterweight is increased, due to the elimination of the traditional through holes for the screws; with the same general volume of the counterweight, this allows to reduce the specific weight of the concrete mix, with lower production costs.

Furthermore, the interposition of the said adhesive layer, which is intrinsically provided with high elasticity, between the rigid bodies of the counterweight and the tank allows to considerably reduce the vibrations and noise that are produced when the traditional screws are used to provide the mutual fixing.

The idea of making the plastic surface "emerge" from the bottom of the counterweight also allows to incorporate one or more fixing means (such as clips, hooks, insertion or centring pins, etc.) designed to provide the provisional fixing of the counterweight to the tank.

A similar provisional fixing can be useful to handle the tank equipped with the counterweight along the assembly line, before mutual adhesion is carried out; the same is also true for the production phases immediately after adhesion, during the reaction time of the adhesive agent.

For purposes of clarity, the description of the invention continues with reference to the enclosed drawings, which are intended for purposes of illustration only and not in a limiting sense, whereby:

- figure 1 is an axonometric view of the plastic insert designed to be incorporated in the mass of the concrete counterweight;

- figure 2 is a side view of the same insert;

- figure 3 is a cross-section of fig. 2 with plane A-A; - figure 4 is a cross-section with a transversal plane of a counterweight that incorporates the said plastic inserts and the section of the tank where the same is adhered;

- figures 5, 6, 7 and 8 are respectively an axonometric view, a top view and two cross-sections of an alternative embodiment of the insert designed to be incorporated in the concrete counterweight;

- figure 9 is a cross-section with a vertical plane, which shows the fixing method of the insert to the tank.

With reference to figures 1 to 3, the system of the invention provides for the inclusion of a plastic moulded box-shaped insert (1 ) in the mould of a concrete counterweight (10), of the type designed to be mounted on the outside of a tank made of polypropylene or other equivalent plastic materials

(20) for washers, washer/dryer combos and similar household appliances.

In particular, the box-shaped insert (1 ) is basically shaped as an

"upturned tool", with a base circular plate (1a), with a series of equally spaced diverging legs (1 b) that protrude from the perimeter border, whose ends are coupled by means of a circular border (1c) with larger diameter compared to the diameter of the circular plate (1a).

As shown in figure 1 , each leg (1 b) internally incorporates a stiffening rib (1d) for its entire height; as shown in figures 2 and 3, the base circular plate (1 a) is centrally provided with a pin (1e) on the opposite side with respect to the legs (1 b).

Figure 4 illustrates the inclusion method of the insert (1) into the counterweight (10); as shown in this figure, the legs (1 b) of the insert (1 ) must be incorporated deeply in the concrete used to form the counterweight (10) and the circular plate (1a) slightly protrudes from the rear side (10a) of the counterweight (10), thus "emerging" from the surrounding concrete mass. The same figure 4 illustrates the method used to fix the counterweight

(10) to the surface of the tank (20).

As anticipated, fixing is obtained by introducing a layer of adhesive agent (30) between the plastic circular plate (1a) that emerges from the rear side (10a) of the counterweight (10) and the corresponding application point on the plastic surface of the tank (20), after subjecting the two plastic surfaces to a physical-chemical process (according to one of the aforementioned technologies) that is necessary to ensure the efficacious adhesion of the adhesive layer (30).

As shown in figure 4, the exact coupling between the counterweight (10) and the specific application point on the tank (20) is favoured and

"guided" by the insertion of the pin (1e) that protrudes from the plate (1a) of the counterweight (10) into a corresponding housing (20a) that is suitably arranged on the tank (20).

Figure 5 and the following figures refer to another embodiment of the insert (100) that differs from the aforementioned embodiment in a special configuration on the outside of the base circular plate (100a).

A similar configuration is designed to ensure a more stable preventive coupling between the insert (100) and the tank (20), which is provided with suitable means (200) to favour coupling. According to this constructive solution, a basically cylindrical bulb (101) protrudes from the centre of the base circular plate (100a) from the opposite site of the legs (1 b), whose end is provided with a diameter notch (102) that forms two semi-cylindrical arms (103) in symmetric opposite position.

The intrinsic elasticity of the plastic material used for the insert (100) allows the arms (103) to get elastically deformed in case of energetic stress.

In a similar case, they are brought closer by taking advantage of the intermediate notch (102) and then spontaneously and suddenly recover their "natural" distance as soon as deformation ends.

Each arm (103) is provided with a window (104), with an external wedge-shaped projection (105) oriented towards the free end of the bulb (101). At the end, in symmetrically opposite position, the bulb (101) is provided with two wedge-shaped projections (105) that, being joined with the arms (103), are able to elastically modify their mutual distance.

Therefore, it can be stated that the two wedge-shaped projections (105) operate as a pair of fixing clips for the tank (20), as explained below. To favour the coupling of a similar insert (100) with the tank (20), the base plate (100a) is provided with two jaws (G) in symmetrical opposite position with respect to the central bulb (101) designed to cooperate with suitable coupling means provided on the tank (20).

Each jaw (G) is formed of a pair of concentric semi-circular edges, spaced by a short gap (108), of which the first edge (106) with higher height and width directly protrudes from a section of the perimeter border of the plate (100a) of the insert (100), and the second edge (107) with lower height and width occupies a more internal position.

A similar insert (100) is designed to cooperate with a corresponding box-shaped circular support (200) that protrudes from the external wall of the tank (20), as shown in figure 9.

The support (200) is bordered by a sort of collar (201 ) with basically identical height as the external edges (106) of the insert (100); inside the collar (201 ), at about three-quarters of its height, a horizontal wall (202) is obtained with a central hole (203) surrounded by a nozzle (204), whose upper end reaches a height that is slightly lower than the height of the collar (201 ).

The nozzle (204) occupies an internal position with respect to the perimeter collar (201 ) of the support (200), in such a way that a circular gap (205) is formed between them. In view of the above, the insert (100) is efficaciously coupled with the box-shaped support (200) when the insert (100) is engaged and pushed against the support (200) with sufficient energy. The following consequences are contextually produced during this operation: the external borders (106) of the insert (100) externally embrace the collar (201) of the box-shaped support (200); the internal borders (107) of the insert (100) engage inside the gap (205) provided above the box-shaped support (200); the bulb (101 ) of the insert (100) is coupled with the central hole (203) of the box-shaped support (200), in such a way that the notched end passes the hole (203) and its base section (101a) remains basically included inside the nozzle (204) that surrounds the hole (203).

During the insertion of the bulb (101) in the hole (203), the two deformable arms (103) are gradually brought closer.

This effect is directly caused by the increasing energetic interference that is generated between the external wedge-shaped projections (105) that project on the sides of the bulb (101 ) and the perimeter border of the hole (203). However, as soon the two projections (105) pass the hole (203), because of their intrinsic elasticity, the two arms (103) spontaneously divert, allowing the two projections (105) to engage under the perimeter border of the hole (203), thus preventing the occasional uncoupling between the insert (100) and the support (200). It can be otherwise said that the two projections (105) of the bulb (101 ) engage to the lower side of the horizontal wall (202) of the box-shaped support (200).

Also in case of this special version of the insert (100), fixing to the support (200) and the tank (20) is obtained by means of the usual adhesive layer (300) after the physical-chemical activation of the plastic surfaces to be interfaced.

As shown in figure 9, in this case the intermediate layer of adhesive agent (300) has a basically sinusoidal direction.

This is determined by the fact that the adhesive agent must fill the gap (205) above the box-shaped support (200) and the nozzle (204) that surrounds its central hole (203).

The adhesive agent contained in the gap (205) incorporates the internal edge (107) of the support (101) and the adhesive agent contained in the nozzle (204) incorporates the first section of the bulb (101), while the adhesive agent that comes out from the gap (205) into the nozzle (204) directly adheres to the base plate (100a) of the support (100).

Finally, it must be said that, within the scope of the present inventive idea, an alternative technology can be used to make the two plastic surfaces of the counterweight (10) and the tank (20) adhere; this more traditional technology should provide for application of a primer on the said surfaces to favour the adhesion of the intermediate adhesive layer (30).

Claims

1 ) System used to fix concrete counterweights on the outside of tanks for washers, washer/dryer combos and similar appliances, of the type made of polypropylene or other equivalent plastic materials, characterised by the fact that it provides for the following sequence of operations: - moulding of a plastic insert (1 , 100) composed of a plate (1a, 100a) that incorporates one or more legs (1b) towards the inside;

- inclusion of the said insert (1 , 100) inside a mould used to form the concrete counterweight (10), in such a way that, once forming is completed, the legs (1 b) are deeply incorporated into the mass of the counterweight (10) and the plate (1 a) shortly protrudes from the rear side (1 Oa) of the counterweight (10);

- fixing of the plate (1a) of the counterweight (10) against a suitable point of the tank (20) through the interposition of a adhesive layer (30, 300).

2) System as claimed in claim 1 , characterised by the fact that the said adhesive layer (30, 300) is applied after a suitable physical-chemical activation process of the two surfaces to be adhered.

3) System as claimed in claim 1 , characterised by the fact that the said adhesive layer (30, 300) is applied after a primer on the two surfaces to be adhered.

4) System as claimed in claim 1 , characterised by the fact that the plate (1a) of the insert (1 ) has a circular surface and incorporates, starting from its perimeter border, a series of regularly spaced diverging legs (1 b) that are joined at the ends by means of a circular border (1c) with larger circumference compared to the plate (1a).

5) System as claimed in one or more of the previous claims, characterised by the fact that, on the opposite site with respect to the legs (1 b), the plate (1 a) of the insert (1) is centrally provided with a pin (1e) designed to be exactly engaged into a corresponding housing (20a) on the surface of the tank (20).

6) System as claimed in one or more of claims from 1 to 3, characterised by the fact that, according to an alternative embodiment, the insert (100) is designed to engage into a box-shaped support (200) incorporated on the external wall of the tank (20); it being provided with the following protruding elements from the base plate (100a) of the insert (100) and on the opposite site of the legs (1b):

- a cylindrical bulb (101) provided at the end with a diameter notch (102) that forms two elastically deformable semi-cylindrical arms (103) with a corresponding window (104), from which a wedge-shaped projection (105) projects externally, being oriented towards the end of the bulb (101);

- a pair of symmetrically opposite jaws (G), each of them being formed of a pair of concentric semi-circular edges, spaced by a short gap (108), of which the first edge (106) with higher height and width directly protrudes from a section of the perimeter border of the plate (100a) of the insert (100), and the second edge (107) with lower height and width occupies a more internal position. It being provided that the box-shaped support (200) is bordered by a sort of collar (201) with basically identical height as the external edges (106) of the insert (100), which internally incorporates, at about three-quarters of its height, a horizontal wall (202) with a central hole (203) surrounded designed to exactly receive the notched end (102) of the bulb (101) of the insert (100), the said hole (203) being surrounded by a nozzle (204), whose upper end reaches a height that is slightly lower than the height of the collar (201 ), from which is separated by a circular gap (205) able to house with free space the most internal edges (107) that protrude from the base plate (100a) of the insert (100).