DE602006000147T2 - Flat switch and object or individual presence detector with such a switch - Google Patents

Abstract

The switch has a perforated metal plate (3), defining orifices and projections (4). A part of the projections is exposed at a lower side of the switch. The side is provided with holding slugs or studs by duplicate molding using rubber or an elastomer material of 50 shore A hardness. The slugs or studs are distributed along the entire surface of the side and extend over a distance greater than the exposure distance of the projections. An independent claim is also included for a device to detect the presence of a heavy body or an individual, integrating a switch.

Description

TECHNICAL AREA

The The invention relates to a flat switch intended to an electrical control circuit, an electrical circuit for activity a device or to allow the operation of a device to open or - im Opposite - too shut down.

The The invention also relates to an apparatus for detecting presence a heavy body or an individual including such a switch.

One Such presence detector finds various applications. Among these can in particular the safety systems are mentioned, in which the execution of certain actions or the activation of funds, machinery, facilities and in the In general, any device only in the presence of the operator allowed whose presence is thus determined.

This this is especially the case with hoists and other lift trucks, for which Both national and EU standards have come into force which for safety reasons prescribe the use of presence detectors to their operation or their operation permit.

such However, switches are used in other technical fields, especially in the area of elevators, but also in the field of garbage or Waste container.

So It is well known that these are rear with steps of small dimensions are provided to one or more operators over short distances the locomotion of the garbage truck can rise, to board and get off the cab of the tipper-transporting trucks with the aim of gaining time to avoid. However, for safety reasons, the speed of the Trucks during these special stages of transition limited in principle between two discharge zones close to each other, for example, to 35 km / h. Therefore, and at this speed At the top, one can see the mentioned stages with a detector of Presence of the operator (s) provided, which then the effective Limit the speed of the truck to a certain value.

STATE OF THE ART

It Safety safety mats are known, which act as a detector and mainly used to detect the presence of persons or objects in a dangerous one Detect zone to send control pulses or counts to send.

such Safety mats consist of two parallel and electrically conductive, from each other by compressible elements separate contact surfaces, wherein the areas mentioned on their pages, which are opposite to those that cooperate to close an electrical circuit are determined, a coating made of vinyl or polyurethane. One of the mentioned coatings can itself a slip-resistant, typically formed by elevations surface exhibit.

If a pressure on the upper surface the switching mat thus formed is given the compressible Elements and allow so making an electrical contact between the two conductive plates and consequently constitute the closure of the electrical circuit safe.

Such mats are for example in the Scriptures EP-A-1 437 752 described.

however is used in such, in particular on pallet trucks, Type of device for presence detection the production of unwanted electrical contacts due to the linings on which the said Hubwagen to move, watching their own vibrations.

In addition, to ensure a satisfactory lead, the electrical Contactor generally made of copper, which increases the cost of production overly expensive.

The font EP-A-0 395 784 describes also a detection device of the kind in question. It can be seen, however, that the means for spacing the conductive plates recommended in this embodiment consist of spread-out bands, in particular of triangular cross-section, whereby the detection sensitivity of the device is significantly impaired. Namely, these ribbons bend under the action of charge, and due to the nature of the material of which they are made, the contact between the two conductive plates requires a relatively large pressure.

Moreover, such mats have the disadvantage of providing limited comfort, which manifests itself in the operators or users in the long term in the occurrence of observed more and more in the workplace syndromes that verbun with musculoskeletal trauma or disorders those who show up especially in the pelvic area. Such musculoskeletal traumas or disorders are traditionally associated with the progressive repetition of one and the same increased rate of motion.

For example the pelvis plays an obvious role in the case of pallet trucks as a damping element, and one of the problems, their solution the invention has the goal lies in the reduction of the pelvis incoming damping function, so these are musculoskeletal disorders or to eliminate or at least limit trauma.

DISCLOSURE OF THE INVENTION

The Invention thus aims first on a flat switch, which is intended to be an electrical Circuit to open or close, where said switch consists of an electrically conductive plate, which with several protrusions provided substantially perpendicularly with respect to the main plane aligned with the plate, said plate with the connected electrical circuit and in a layer of rubber or elastomer is embedded, wherein at least a part of said projections lies in the plane of one of the sides of the structure thus formed, which is intended, with the edition or with an additional Element cooperate, leading to the formation of said circuit contributes.

According to the invention this conductive plate formed by a perforated plate, which except the said projections a plurality of openings forms. Such a conductive plate thus has simultaneously Rigidity and flexibility properties on what allows that it bends under the action of a charge, so to speak allow that the projections in the layer of rubber or elastomer in electrical Contact with the pad or come with an additional element which contributes to the formation of said circuit.

It also includes the questionable side of said structure guard pins or blocks, which essentially over distributed this entire surface are and their height the length exceeds the flush tabs.

So can such a flat switch advantageously on the metallic frame of a machine, a plant or a vehicle be positioned, which at the zero potential, that is the mass, is brought, with the plate in turn to a non-zero Potential is brought.

hereby calls production of contact of a plate with metal Frame with the help of flush projections the closure the circuit and consequently the possible activation of other associated means or the operation of a lift truck.

According to the invention other side of the structure, that is the one with the guard pins or blocks provided opposite Side, with elevations provided, which are advantageously formed by molding and additionally to the possible Optimization of damping ability The flat switch is designed to give the structure non-slip properties lend, with these increases can have any shape and advantageously evenly over the questionable side are distributed.

According to the invention Guard pins or blocks perpendicular to all or part of the zones without increasing the opposite Page arranged.

According to the invention this flat switch a lower part (previously as the additional Element defined), that of a uniform and level electrically conductive plate is formed, which with rubber or elastomer is molded / cast, except one of its two Main areas wherein said plate is also connected to the electrical circuit is connected, which was previously mentioned.

This uniform conductive plate is intended to come into contact with the flush projections of the aforesaid structure when sufficient pressure is applied to the upper surface of said structure which is suitable for the curvature or bending of the side provided with the guard pins or pads to cause contact between the flush projections and the uniform plate of the lower part, regardless of the guard pins or pads. Typically, for a run having a cross-section of about 50 m ^2, the required pressure is between 2 and 7 daN. This gives the structure sufficient sensitivity depending on the intended applications because, as already noted, it is the projecting conductive plate which bends or bends while the pins or pads undergo almost no deformation.

The lower part is fixedly connected to the upper part in its respective edge region, advantageously by gluing after being joined together, said parts being of substantially the same length and width apart from the zone in which they fit together become.

Besides and in order to optimize the tightness of the structure thus obtained is In the area of this edge zone a cord of silicone in each case in contact attached with the two parts.

Around Furthermore To optimize this bond, the materials for forming / molding of the lower or upper part of the same nature.

advantageously, has the bottom of the lower part, which therefore not the opposite to the formed / cast zone, preferably formed by molding honeycombs, the function of dampers ensure that these honeycomb are suitable to any cross section and in particular to adopt a quadrangular or polygonal cross-section.

These Structure is advantageously used in the case of a device for Detecting the presence of a body or an individual with the goal of reinforcement the safety of the devices in which they are installed is.

BRIEF DESCRIPTION OF THE DRAWINGS

The Way in which the invention can be carried out and which Benefits derived from it are better understood from the following and suggestive and not restrictive with the help of the attached Figures given embodiment out.

1 is a schematic representation in plan view of a device for detecting the presence of a body or an individual according to the present invention, from the 2 is a bottom view.

3 is a schematic cross-sectional view of the detection device of 1 and 2 , of the 4 a more detailed view is.

5 FIG. 12 illustrates the perforated sheet inserted within the upper part of the presence device of the preceding figures.

6 illustrates the uniform plate used within the lower part of the presence device of the preceding figures.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT THE INVENTION

The embodiment described in connection with the attached figures relates to a complete apparatus for detecting presence, that is with an upper part 1 and a lower part 2 This device is intended to fulfill the function of a safety mat, in particular for a pallet truck, that is, to be placed in the area of positioning of the operator of said car under normal operating conditions, said mat being electrically connected to the activating means of said Car is connected to prevent its functioning when no presence is detected.

however limited Of course, the invention not only on this execution or application form.

Thus, according to this particular embodiment, the detection device has one with a lower part 2 firmly connected upper part 1 on, wherein the arrangement forms a substantially flat structure whose thickness is relatively small in terms of the dimensions of its length and its width, such as in 3 can be observed. Thus, in the example described, the safety mat has a height of about 20 mm, while its width and height can be considerably greater.

The upper part 1 consists essentially of a perforated sheet metal 3 , which forms a plurality of openings, but above all a certain number of projections 4 which are aligned substantially perpendicularly with respect to the principal plane of said sheet and at least a part of which is directed towards the lower part 2 is turned.

This Sheet metal is made of any electrically conductive material. So it can be made of steel of type F12T3S1, which subjected to a high zinc anti-corrosion treatment stainless steel such as 304L stainless steel (IUP - ARCELOR), this means austenitic stainless steel, which has good properties for fighting having corrosion.

This perforated sheet 3 also has a cutout in the region of one of its lateral sides, which is a contact shoe 5 forms, which is intended to allow the electrical connection of the sheet with an electrical cable or wire of an electrical control or processing circuit.

According to the invention, this sheet is 3 , of a typical thickness of 0.25 mm, by reshaping or casting in an elastomeric layer 6 embedded.

More precisely, that covers by means of a press sprayed elastomer layer 6 the entire upper surface of the sheet 3 from. In contrast, receives the bottom of said sheet, that is, the interaction with the lower part 2 the presence detector determined only a simple rubber or elastomeric veil. By doing so and by taking advantage of the known shrinkage of rubber or elastomer in its cooling after injection, the projections protrude 4 of the sheet 3 slightly, typically by a distance between 0.05 and 0.2 mm to the level of the underside of the upper part 1 , out.

Consequently, this bottom is formed by molding over the aforementioned rubber or elastomeric material with guard pins or pads 7 which are evenly distributed, as in broken lines in 1 is observed, and over a distance greater than the distance of projecting the projections 4 from the height of said page, as in 4 can be observed.

In the present case, in relation to the flat part, it is the underside of said upper part 1 measured height of guard pins or pads 7 about 0.6 mm.

In addition, and according to an advantageous feature of the invention, the upper side of said upper part 1 elevated zones 8th which are also advantageously formed by molding / casting and which in the example described have the shape of a spherical cap. As in the 1 and 4 is observed, these increases are also distributed evenly.

These elevated zones 8th are initially intended to give the safety mat anti-slip properties. But they also favor the ability to absorb vibrations, and thus generally damp the mat, with the aim of combatting the musculoskeletal disorders raised in the disadvantages of the prior art devices.

According to a feature of the invention, the guard pins or pads are 7 the underside of the upper part 1 essentially perpendicular to the zones 9 the top arranged which these raised zones 8th do not have. This feature appears very clearly in 1 ,

The process of forming / encasing this perforated sheet 3 elastomer used in the example described consists of a nitrile with a hardness of 50 Shore A. This material has the peculiarity of being particularly resistant not only to abrasion but also in aggressive and especially acidic environments and consequently to promote the life of the product. Moreover, the selected hardness gives it a relatively large damping capacity, which favors the fight against musculoskeletal disorders.

According to the described embodiment, the presence detection apparatus also includes a lower part described in more detail below 2 ,

First, this one with those of the upper part 1 essentially identical length and width. Advantageously, it fits into said upper part, which is then provided with a peripheral edge which is suitable for forming the zone for receiving the lower part.

The lower part 2 essentially comprises a flat, uniform and continuous electrically conductive plate 10 , It is made of metal and has a typical thickness of 1 millimeter to give it some rigidity in view of its function described in more detail below and its incorporation into the presence detection apparatus of the invention.

This bottom plate 10 , with those of the perforated sheet 3 of the upper part 1 essentially equivalent dimensions (length and width), like this one has a section 11 on, which forms a contact shoe, which is intended to be also connected to an electrical wire or cable of the aforementioned electrical circuit.

This bottom plate 10 is also formed / cast, advantageously with the same material as the material for forming / casting over the perforated sheet 3 of the upper part 1 However, this forming / Umge is not in the top 11 the said plate is present, that is the side which cooperates with the upper part 1 the detection device is determined.

The lower part 2 points in the area of the page 11 the plate 10 opposite side a certain number of honeycombs also formed by molding / casting 12 on.

These honeycombs are relatively deep with respect to the thickness of the detection device and have a quadrangular or polygonal cross-section. They are intended to give said detection device their damping characteristics, which are sought in particular in the context of the present invention. In this context, it should be emphasized that the choice of material for forming / casting, as mentioned above, significantly contributes to this damping Fung contributes insofar as its limited hardness gives the assembly some flexibility, which favors the deformation of the mat and thus its function as a filter of vibration and other vibrations.

Of the thus produced lower part is connected to the upper part by gluing assembled in the edge area of the respective parts.

Of the used adhesive can of any, with the used Rubber or elastomeric material compatible nature and may in the example described a slow binding cyanoacrylate adhesive, as described by the Permabond company under the item number C737 is sold.

As soon as the adhesive is applied in the peripheral region, is a cold pressing, optionally with a heating phase (40 to 50 ° C during about ten minutes), performed, to accelerate the bonding of the adhesive.

As a result, this adhesion process ensures the tightness of the structure thus produced and thus makes it possible to eliminate any corrosion phenomena which may affect the conductive metal elements serving as insert parts, in particular the perforated metal sheet 3 and the metal plate integrated within said structure 10 ,

However, it is possible to further optimize this tightness, after this adhesive phase in the region of the circumference of the structure a cord of silicone 13 to attach, this cord is in contact with the upper and lower part.

Moreover, they are in the area of the perforated sheet 3 as well as the uniform plate 10 formed shoes 5 respectively. 11 tinned, which favors the soldering of the electrical wire or cable, with which they are respectively to be firmly connected, and avoids the penetration of the material for forming / casting in this area. Namely, the step of forming / overmolding takes place later than the attachment of said electric wires or cables to the respective metallic insert parts.

In addition, will heat shrinkable wrap or even double-hulls over these Shoes and the wires or cables with which they are welded, slipped to to further optimize the tightness of the structure.

In this way, on the one hand due to the material used for forming / Umge, on the other hand, due to the distribution of the protective pins or blocks and the relative structure of the conductive elements, when sufficient pressure is applied to the thus formed switching mat, said pressure with the presence of a Operator or an object goes along, a contact between a part of the projections 4 and the uniform metal plate 10 due to the curvature of the sheet 3 whereby the closure of the electrical circuit to which the device is connected is ensured and consequently the activation of the means, device or device, and in the present case the lift truck, within which the detection device thus formed is incorporated, is permitted Opposite is prevented.

The generated pressure causes namely the partial curvature of the upper part 1 and thus the sheet 3 and consequently the downward movement of the projections 4 in contact with the plate 10 regardless of the presence of guard pins or pads 7 whose function is precisely to prevent these unwanted contacts but whose distribution and dimensions are chosen to allow the production of such electrical contacts at a pressure, hence a force, and thus at a given mass.

If the presence detector in the example described an upper Part and a lower part, so the invention relates also a presence detector, restricting only off the upper part, as soon as constraints, especially in relation to on the tightness, do not occur. For the good functioning of the Device is sufficient that they are connected to a grounded, conductive Metal frame is positioned, the device in the frame of the electrical circuit in question itself to a zero different potential is brought.

In addition, if in the example described, the top of the upper part 1 with elevations 8th It should be emphasized that the presence of such elevations is not essential to the functioning of the device of the invention.

In Likewise, in the device of the invention, the honeycomb structure their lower part is missing, since these essentially a damping and thus fulfilling comfort function. When it comes to comfort, the hardness of the shoe can be equally useful converted / encapsulated rubber or the elastomer can be used.

you Consequently, numerous applications of the detection device can occur of the invention.

So, except the already mentioned In connection with safety, due to the tightness imparted to the said device, the applications in connection with the medium of water are also referred to, where the device serves as a chronometric contact during sporting events. The swimmer must press a contactor when he finishes the competition to stop the stopwatch.

But this detection device can also be at the bottom of swimming pools be sunk to a swimmer or any person which threatens to drown, and consequently the triggering of a Cause alarm signal.

such Detecting devices whose manufacturing costs are low, therefore, can manufactured for large surfaces be placed or in critical locations, such as bank branches and other places of the same kind.

numerous Advantages result from the detection device of the invention. Except the previously mentioned can also their life and their reliability are called, which, except because of its embodiment, are also increased due to the materials used.

In addition, recover these devices pose no danger as they operate at low voltage can be typically at 12, 24 or 48 volts at a low current of 0.2 to 0.3 A.

moreover can such detectors a usable area, this means an area suitable for generating a signal, nearly 100% of its area total surface exhibit.

Finally are They are suitable for use in a variety of circumstances and in aggressive environments in turn, due to the choice of ingredients.

Claims (11)

Flat switch designed to open or close an electrical circuit with an electrically conductive plate ( 3 ) which is embedded in a layer of rubber or elastomer and is connected to said electrical circuit, which is provided with a plurality of projections ( 4 ) which are oriented substantially perpendicularly with respect to the main plane of the plate and intended to cooperate with the support or with an additional element which contributes to the formation of the electrical circuit, characterized in that the conductive plate ( 3 ) is formed by a perforated sheet, which except the said projections ( 4 ) forms a plurality of openings that at least a part of said projections ( 4 ) lies in the plane of one of the sides of the structure thus formed and that said side is provided with protective pins or blocks ( 7 ), which are distributed substantially over their entire surface and the height of the length of the flush projections ( 4 ) exceeds. Flat switch according to claim 1, characterized in that the other side of said switch, ie that with the protective pins or blocks ( 7 ) provided opposite sides, with elevations ( 8th ) is provided. Flat switch according to one of claims 1 and 2, characterized in that the protective pins or blocks ( 7 ) perpendicular to all or part of the zones ( 9 ) without increase ( 8th ) are arranged on the opposite side. Flat switch according to one of claims 2 and 3, characterized in that the elevations ( 8th ) are formed by molding and have any shape. Flat switch according to one of claims 2 to 4, characterized in that the elevations ( 8th ) are evenly distributed over the area in question. Flat switch according to one of claims 1 to 5, characterized in that it has a lower part ( 2 ) of a uniform and planar, electrically conductive plate ( 10 ) formed with rubber or elastomer, except for one of its two major surfaces, said plate also being connected to the electrical circuit and intended to be in contact with the flush projections ( 4 ) of the conductive plate ( 3 ), when sufficient pressure is applied to the top of the switch, which is capable of reversing the curvature of the guard pins or switches ( 7 ) and thus the contact between at least a part of the flush projections ( 4 ) and the plate ( 10 ) of the lower part, regardless of the guard pins or blocks, and so close the electrical circuit. Flat switch according to claim 6, characterized in that the lower part ( 2 ) by gluing firmly to the upper part ( 1 ) connected to the plate provided with the projections in its edge region (FIG. 3 ) is formed. Flat switch according to one of claims 6 and 7, characterized in that the materials for forming the lower or upper part are of the same nature. Flat switch according to one of claims 6 to 8, characterized in that the underside of the lower part ( 2 ), which consequently the non-deformed region of the conductive plate ( 10 ), honeycombs ( 12 ), which ensure the function of dampers, which honeycomb are adapted to assume any cross section and in particular a quadrangular or polygonal cross section. Flat switch according to claim 9, characterized in that the honeycombs ( 12 ) are formed by molding. Device for detecting the presence of a heavy body or an individual, characterized in that it has a switch according to one the claims Contains 1 to 10, the closing or open an electrical circuit ensures that the operation of any means, Controls devices or devices.