EP2447972A1

EP2447972A1 - Control push-button unit for electric plants and method and tooling for manufacturing such a push-button unit

Info

Publication number: EP2447972A1
Application number: EP11008478A
Authority: EP
Inventors: Marco Pizzato
Original assignee: Pizzato Elettrica SRL
Current assignee: Pizzato Elettrica SRL
Priority date: 2010-10-28
Filing date: 2011-10-21
Publication date: 2012-05-02
Anticipated expiration: 2031-10-21
Also published as: BRPI1104822B1; ITVI20100289A1; EP2447972B1; BRPI1104822A2; CN102543521A; CN102543521B; IT1402695B1

Abstract

A method for manufacturing a control push-button unit (2) for plants comprises the steps of shaping a lower half (4) and an upper half (5) couplable to form a box-like case (3), providing a plurality of electric elements (8, 9,10, 11, 12) and their positioning between the lower half (4) and the upper half-shell (5). The step (a) of shaping the upper half (4) comprises the steps of providing a first mold (1) having a central cavity (14) with a bottom wall (15) and an upper opening (16), inserting a matrix (17) in the cavity (14), such matrix having a shaped lower face (18) facing the bottom wall (15) to define an interspace (20) therewith. The matrix (17) is formed by a plurality of first modular inserts (21, 21', 21",...) designed to realize housing seats (7, 7', 7") for the electric elements (8, 9,10, 11, 12), such inserts appropriately positioned in the cavity (14) with their lower surfaces (22, 22', 22") defining the lower face (18) of the matrix (17). A control push-button unit for plants obtainable with the method according to the invention.

Description

Field of application

The present invention is generally applicable to the technical field of electrical devices for controlling electric plants for moving and conveying people and/or objects and particularly has as object a method and a tooling for manufacturing a control push-button unit for electric or electromechanical plants, such as elevators, hoists and the like, for controlling the same during maintenance and inspection operations.
The invention also has as object a push-button unit obtained by means of the method and/or the tooling mentioned above.

State of the Art

It is known to apply multiple control push-button units to civil or industrial plants, such as elevators, hoists, cranes, overhead cranes and the like, in order to control the movement of the movable parts of such plants, particularly during maintenance and inspection operations.
Typically, the push-button units comprise a box-like case containing a plurality of electrical contacts therein for connecting to the power-supply circuits and service circuits of the plant.
Push-button units are also provided with a plurality of switches or controls arranged on the upper face of the box-like case and connected to respective electrical contacts for controlling the various movements of the plant or switching the same between multiple functioning conditions.
The arrangement and the number of controls vary according to the type of plant to be controlled, as well as the functions of the same that require controlling.
Generally, push-button units can comprise one or more controls for moving the movable part of the plant along respective directions, e.g. for controlling the upward or downward movement of an elevator cage, a multifunction button for managing the signaling circuits and other possible auxiliary controls.
For example, a selector can be provided, configured to be manually driven and to switch the plant between a normal functioning mode and an inspection functioning mode.
An auxiliary current socket can also be provided for connecting a service device to the push-button unit, e.g. a lamp or an electric tool, to be used in inspection operations.
Push-button units can also comprise an emergency button, typically a mushroom button, for the immediate interruption of the power supply of the plant or a part thereof, in a manner so as to bring it into safety condition.
Typically, the process for manufacturing the push-button unit provides for a step of molding the box-like case by means of a mold suitably designed for the specific push-button unit.
In this manner, one obtains a case arranged for the application of a predetermined number of buttons according to a predefined scheme.
A first recognized drawback of these known solutions is represented by the fact that for every push-button unit, it is necessary to design a specific mold.
Indeed, each control has its specific configuration and its own coupling systems that differ with respect to the other commands.
Therefore, when it is necessary to design a series of push-button units, it is also necessary to provide for the design and manufacturing of a plurality of molds, with clear cost increases.
In order to at least partly overcome these drawbacks, several solutions have been proposed aimed to standardize the molds as much as possible, maintaining a common part for all the possible configurations of the push-button unit.
For example, known from US 2,979,581 is a modular electric push-button unit, having a case provided on its upper face with a plurality of holes for the passage of the controls.
The controls are formed by a first portion intended to be inserted and fixed in any one of the holes and a second external portion that can vary according to the button type, in a manner such that to modify the configuration of the push-button unit, it will suffice to remove only the external portions of one or more controls.
However, such solution does not allow modifying the number or the general arrangement of the controls and moreover requires that each control be provided with a coupling portion - which increases the overall cost.
Known from US 4,209,820 is instead an electric push-button unit, formed by a containment shell having an upper opening through which it is possible to introduce the buttons with the relative wiring.
The application of the buttons to the shell is obtained by means of a plate provided with a plurality of holes for the passage of respective buttons.
If a different configuration of the buttons is desired, one proceeds with the removal of the plate and its substitution with a different plate having a different number of buttons and/or a different button arrangement.
Also in this case, however, it is necessary to arrange a specific plate for each of the configurations to be attained for the push-button unit, such that the manufacturing process of the series of push-button units still has excessively high cost.

Presentation of the invention

The object of the present invention is to overcome the drawbacks described above, by providing a method and a tooling for manufacturing control push-button units for movement and transport plants, particularly elevators and the like, that is particularly economical and effective.
A particular object is to provide a method that allows manufacturing a multiplicity of push-button units having a different number and/or type and/or distribution of controls by means of a single mold.
A particular object is to provide a tooling having a mold for manufacturing a control push-button unit for plants that allows obtaining a multiplicity of configurations for the mold, considerably reducing the costs for manufacturing a series of push-button units having a different number and/or type and/or distribution of controls.
Such objects, as well as others which will appear clearer below, are attained by a method for manufacturing control push-button units for plants, in accordance with claim 1, comprising the steps of shaping at least one lower half-shell and at least one upper half-shell, providing a plurality of electric elements comprising contacts, positioning said electric elements between said at least one lower half-shell and said at least one upper half-shell, and coupling said at least one lower half-shell and at least one upper half-shell to form a box-like case designed to enclose said plurality of electric elements.
The step of shaping the upper half-shell comprises the steps of providing a first mold having a central cavity with a bottom wall and an upper opening, inserting a core or matrix in said central cavity, such core or matrix having a shaped lower face substantially facing said bottom wall to define an interspace therewith, and inserting a plastic material into said interspace to form said at least one upper half-shell.
The method is characterized in that the core or matrix is formed by a plurality of substantially prismatic first modular inserts designed to realize housing seats for said electric elements and each having a lower surface, said first inserts being suitably positioned in said cavity with said lower surfaces defining the lower face of said core or matrix.
According to a further aspect of the invention, a tooling is provided for manufacturing control push-button units for plants, in accordance with claim 5, comprising at least a first mold for obtaining at least one upper half-shell.
The first mold comprises a containment portion with a central cavity having a bottom wall and an upper opening, a core or matrix insertable in said cavity and having a shaped lower face intended to be faced to said bottom wall to define therewith an interspace designed to be filled with a plastic material to form said at least one upper half-shell.
The tooling is characterized in that the matrix comprises a plurality of first modular inserts, each having a lower surface defining a portion of said lower face of said matrix and having shape complementary to that of said housing seats.
Due to these particular characteristics of the invention, the method and the tooling will allow obtaining a plurality of push-button units provided with different control configurations, by simply providing a different distribution of the inserts inside the cavity.
Due to the particular characteristics of the tooling according to the invention, it is possible to make a potentially unlimited number of similar push-button units having a substantially identical box-like body, which differ regarding the number and/or type and distribution of the electric elements.
According to still another aspect of the invention, a push-button unit for controlling plants is provided, in accordance with claim 12, obtainable with the method and/or tooling according to the invention.
Advantageous embodiments of the mold, of the method and the assembly are achieved in accordance with the dependent claims.

Brief description of the drawings

Further characteristics and advantages of the invention will be clearer in light of the detailed description of a preferred but not exclusive embodiment of a method and a tooling according to the invention for manufacturing a control push-button unit for plants according to several preferred configurations, as well as several embodiments of push-button units obtainable with such method and tooling illustrated as a non-limiting example with the aid of the drawing table set, in which:

FIG. 1 is a perspective view of a mold according to the invention;
FIG. 2 is a perspective view of a push-button unit that can be at least partly obtained with a mold according to the invention;
FIG. 3 is a partially exploded perspective view of the mold of Fig. 1;
FIGS. 4 and 5 respectively represent a top view and a section view along the plane V-V of Fig. 4 of a mold according to the invention found in a first preferred configuration;
FIG. 5A is an enlarged view of a detail of Fig. 5;
FIGS. 6 and 7 respectively represent a top view and a section view along the plane VII-VII of Fig. 6 of a push-button unit portion obtainable with the mold according to the configuration of Figs. 4 and 5;
FIGS. 8 and 9 respectively represent a top view and a section view along the plane IX-IX of Fig. 8 of a push-button unit portion according to the invention in a second preferred configuration;
FIGS. 10 and 11 respectively represent a top view and a section view along the plane XI-XI of Fig. 10 of a mold according to the invention in a second preferred configuration for obtaining the push-button unit portion of Figs. 8 and 9.

Detailed description of a preferred embodiment

In Fig. 1 , a mold is illustrated according to the invention, indicated overall with 1, usable for obtaining a series of push-button units designed to be installed in proximity to a movement or transport plant.
A merely exemplifying and non-limiting example of a push-button unit obtainable with the mold 1 according to the invention is illustrated in Fig. 2 , in which the push-button unit, indicated with 2 overall, is of the type applicable to a movement plant, such as an elevator or hoist, not illustrated since this is known.
For example, the push-button unit 2 can be installed in a cage or in the pit bottom of an elevator plant, for controlling and moving the elevator during inspection and maintenance operations.
Naturally, the push-button unit 2 can be used in combination with any other type of movement or transport plant, such as, in a non-limiting manner, movable walkways or escalators, cranes, overhead cranes and the like, according to modes known to the man skilled in the art and for this reason not investigated further herein.
In particular, a push-button unit 2 at least partially obtainable with the mold 1 according to the invention can comprise a box-like case 3 housing therein a plurality of fixed and/or movable electrical contacts, not illustrated since they are of known type.
The type and the number of electrical contacts can be selected as a function of the configuration of the plant to be served, in an obvious manner for the man skilled in the art.
In particular, the box-like case 3 will define a longitudinal axis L and can be formed by at least one lower half-shell or portion 4 and at least one upper half-shell or portion 5, bound together in a fixed or removable manner, e.g. by means of screw members or the like.
Alternatively, the half-shells 4, 5 can also be integrally made by means of a single molding step.
In an embodiment not illustrated in the drawings, the lower half-shell 4 can be substantially flat to define the bottom wall of the upper half-shell 5.
Possibly, there can also be more than two portions or shells, provided that they define the box-like case 3.
The upper portion 5 will have a substantially flat upper wall 6 for the upper closure of the box-like case 3, and in such wall a plurality of substantially transverse through seats 7, 7', 7",... are obtained.
Each of such seats 7, 7', 7",... will be configured for housing respective electric elements comprising controls to be electrically connected to respective electrical contacts and/or electrical connections.
The number and the type of electric elements will be defined as a function of the use for which the push-button unit 2 is intended.
In a merely exemplifying manner, the electric elements can be selected from among all common electric devices connectable to corresponding pairs of electrical contacts for controlling the power-supply and/or service circuits of the plant.
Generally, the push-button unit 2 can comprise an emergency button 8 connectable to the power-supply circuit of the plant for the interruption/activation of the latter or a part thereof.
Other controls can be a selector 9, adapted to switch the plant between normal functioning and functioning during inspection, and one or more control buttons 10 for controlling the ascent and descent of a movable part of the plant, such as a cage.
One or more double or triple multifunction buttons 11 can be provided for managing the signaling circuits, and an electrical socket 12 can be provided for the possible connection and electrical power supply of a further external electrical device (not illustrated), such as a service lamp or an electric tool.
Two separate configurations of an upper portion 5 of a push-button unit 2 provided with seats 7, 7', 7", 7"', 7^iv for housing the controls are illustrated in Figures 6 to 9 .
Below, for the same of simplicity, the housing seats 7, 7', 7", 7"', 7^iv will be indicated with the single reference number 7 without prime, it being understood that, where not otherwise specified, that indicated for the seat 7 will be referable in an analogous manner also to the seats 7', 7", 7"', 7^iv.
In these exemplifying configurations, the upper half-shells 5, even if having a same number of housing seats 7, will be different due to seat type and/or distribution.
A mold 1 according to the invention, belonging to a tooling for obtaining a plurality of push-button units 2 that are differently configured with regard to the number and/or type and/or distribution of the housing seats 7, will essentially comprise a box-like containment portion 13 having a central cavity 14 with a bottom wall 15 and an upper opening 16.
Inside the cavity 14 of the box-like portion 13, a core or matrix 17 is also removably insertable, such core or matrix 17 having a shaped lower face 18.
The latter is intended to be faced to the upper surface 19 of the bottom wall 15 to define therewith an interspace 20 of predetermined shape corresponding with that of the half-shell 5 of the push-button unit 2 to be molded.
In the illustrated exemplifying configuration, the mold 1 according to the invention will be designed for obtaining only the upper half-shell 5 of the push-button unit 2, which represents the variable part among push-button units of the same series.
The lower portion or half-shell 4 can be obtained by means of a further mold, not illustrated, the only mold for all the push-button units or by means of any other known execution mode.
Nevertheless, it is clear that the man skilled in the art can configure the mold 1 according to the invention in order to also allow the obtainment of the entire box-like case 3 or of any one part thereof.
According to one particular characteristic of the invention, the matrix 17 comprises a plurality of first modular inserts 21, 21', 21",....
Also in this case, for the sake of simplicity, reference will be made to a single first insert 21 and to the relative parts indicated with reference numbers without prime, it being understood that, where not otherwise specified, all that indicated for the first insert 21 will be found in an analogous manner, even if possibly structurally and/or dimensionally different, for the other first inserts 21', 21",...
According to an advantageous aspect of the invention, each first insert 21 has a respective suitably-shaped lower surface 22 defining a portion of the lower face 18 of the matrix 17.
In particular, each first insert 21 will have a shaped lower surface 22 with shape complementary to that of a corresponding housing seat 7, or of a portion thereof, to be obtained on the upper half-shell 5 of the push-button unit 2.
The cavity 14 can have any plan shape and the first inserts 21 can also define only one portion of the matrix 17 in order to be distributed in the cavity 14 according to any one distribution scheme, in positions not necessarily adjacent to each other.
Suitably, the central cavity 14 will have elongated form along a longitudinal direction X with a substantially rectangular upper opening 16 of length l and width w previously measured, respectively, along the longitudinal direction X and a first transverse direction Y orthogonal thereto.
In turn, the first inserts 21 of the matrix 17 will be configured to be housed in the cavity 14 in longitudinally offset positions according to a plurality of combinations suitable for defining corresponding shapes for the interspace 20 and corresponding distributions for the respective housing seats 7 of the controls.
According to a configuration not illustrated in the figures, the matrix 17 can comprise a support structure with a plurality of housings for the inserts 21, which can also be in non-adjacent positions.
Nevertheless, according to the preferred configuration illustrated in the figures, the first inserts 21 can be arranged in adjacent positions, according to a plurality of distributions, and the matrix 17 will be entirely constituted by such inserts 21.
The shape of the first inserts 21 will be selected as a function of the configuration of the cavity 14 of the mold 1.
For example, they can be substantially prismatic, with rectangular plan form with a pair of opposite sides having a maximum width d₁ substantially equal to the width w of the upper opening 16 of the cavity 14.
As is observed in Fig. 3 , the first inserts 21 will have a main prismatic body 23 with a projecting peripheral edge 24 designed to abut against a peripheral projection 25 obtained on the internal side surface 26 of the cavity 14.
In this manner, the shaped lower surfaces 22 of the first inserts 21 will be spaced with respect to the bottom wall 15 of the cavity 14 in order to define the interspace 20.
Advantageously, the first inserts 21 will be configured to be arranged longitudinally side-by-side and in mutual contact. In particular, each first insert 21 will have flat, mutually parallel side surfaces in order to allow the side-by-side positioning in mutual contact with one first insert or with a pair of adjacent first inserts 21.
In addition, the first inserts 21 will have respective pairs of second sides orthogonal to the first sides and having respective predetermined lengths d₂ which can all be equivalent or different from each other, or with only some lengths coinciding.
In particular, the first inserts 21 will be selected to define a matrix 17 having length substantially equal to that l of the upper opening 16 of the cavity 14.
According to a preferred configuration, more clearly visible from the sections of Figures 5 and 11 , also the bottom wall 15 of the cavity 14 will be formed by a plurality of second inserts 27, 27', 27",... having respective suitably-shaped upper surfaces 28, 28', 28",....
Also in this case, for the sake of simplicity, reference will be made to a single second insert 27 and to the relative parts indicated with reference numbers without prime, it being understood that, where not otherwise specified, all that indicated for the second insert 27 will be found in an analogous manner, even if structurally different, for the other inserts 27', 27", ...
In particular, each of the second inserts 27 will be substantially aligned with a corresponding first insert 21 along a second transverse direction Z orthogonal to the upper opening 16.
In this manner, pairs of transversely-aligned first and second inserts 21, 27 will be defined, with respective lower 22 and upper 28 shaped surfaces delimiting a longitudinal interspace portion 20, as is more clearly visible from Fig. 5A .
Preferably, each of the second inserts 27 will have rectangular-shaped plan, with dimensions substantially coinciding with the width d₁ and length d₂ of the corresponding first insert 21 aligned transversely thereto.
The upper surfaces 28 of the second inserts 27 can be flat, or shaped with suitable form, e.g. with a central or peripheral recess, as a function of the shape desired for the housing seat 7 to be obtained.
According to a particularly advantageous aspect, the containment portion 13 of the mold 1 can have one or more removable side portions 29, 30, adapted to define a lateral access to the cavity 14 for the insertion of the first and/or second inserts 21, 27.
In particular, the insertion of the inserts 21, 27 can occur by means of longitudinal sliding of the same in the cavity 14 through the lateral accesses. In particular, the first inserts 21 will slide with their projecting edges 23 along the longitudinal sections of the peripheral projection 25, which will act as guides.
The containment portion 13 can be formed by a pair of half-shells 13', 13" separable from each other in order to allow the opening of the mold 1 and the convenient collection of the molded piece.
The usable materials, both for the containment portion 13 and for the matrix 17, are those commonly employed in the field and can be metal or polymer materials.
The maximum number of first and/or second inserts 21, 27 insertable inside the cavity 14 will depend on the dimensions of the cavity 14, in particular its length l, and on the lengths d₂ of the inserts 21, 27.
According to a further particularly advantageous aspect of the invention, the tooling according to the invention, in addition to the mold 1 described above, can be provided with series of first and/or second inserts 21, 27 with a higher amount than the maximum number of inserts insertable in the cavity 14.
Thus it will be possible to considerably increase the number of configurations obtainable with the same tooling formed by the mold 1 and by the series of inserts 21, 27, in such a manner limiting the production costs.
The use of a tooling according to the invention for manufacturing a push-button unit 2 can be made clear by the presence of transverse ribs 31 on the closure wall 6.
Such ribs 31 will be interposed between longitudinally-adjacent electric elements 8, 9, 10, 11, 12 and will correspond to the positions of the transverse edges of the first inserts 21 during the molding step.
A particular aspect of the invention is constituted by the method for manufacturing the push-button unit 2 of the above-described type that can be executed, preferably but not necessarily, with a tooling of the above-described type.
In particular, the method can comprise, not necessarily in the reported sequence, a step a) of shaping the lower half-shell 4 and the upper half-shell 5, a step b) of providing a plurality of electric elements 8, 9,10, 11, 12 comprising electrical connection members or contacts, a step c) of positioning the electric elements between the two half-shells 4 and 5, and a step d) of coupling the latter to form a box-like case 3 intended to close the electric elements 8, 9,10, 11, 12.
The steps from b) to d), along with the formation of the lower half-shell 4, can be obtained according to any one of the modes commonly employed in the field, without any limitation of the protective scope of the present invention.
The step a) of shaping the upper half-shell 5 will instead comprise a step e) of providing a mold 1 comprising a box-like containment portion 13 with a central cavity 14 having a bottom wall 15 and an upper opening 16, and a step f) of providing a core or matrix 17 having a shaped lower face 18.
Subsequently, one will proceed with the insertion of the matrix 17 in the cavity 14 with its lower face 18 facing the upper face 19 of the bottom wall 15.
In this manner, the two faces 18 and 19 will delimit an interspace 20 with predetermined shape corresponding to that of the portion to be molded 5 of the box-like body 3 of the push-button unit 2.
The method can provide for a step g) of inserting a melted plastic material into the interspace 20, essentially in the fluid or semi-fluid state, intended to define the upper half-shell 5 to be molded.
The insertion of the melted plastic material will preferably occur via high pressure injection, according to the common molding techniques of known type. Nevertheless, it can be substituted by any one other known molding technique.
According to the particular characteristic of the invention, the step of inserting f) the matrix 17 provides for a step of arranging a first plurality of substantially prismatic first modular inserts 21.
Each first insert 21 has a shaped lower surface 22 with shape complementary to that of a corresponding seat 7, or of a portion thereof, for housing a control.
Subsequently, one proceeds with a step of arranging the first inserts 21 in the cavity 14 according to a predetermined configuration, in a manner such that the lower surfaces 22 define the lower face 18 of the matrix 17.
In addition, there can be a further step of providing a second plurality of second inserts 27 of the above-described type, each having a shaped upper surface 28.
Each of the second inserts 27 will be inserted in the cavity 14 in a manner such that their shaped upper surfaces 28 define part of the upper surface 19 of the bottom wall 15.
The mutually-facing lower and upper surfaces 22, 28 of the first and second inserts 21, 27 respectively delimit an interspace portion 20.
Advantageously, pairs of mutually-facing first and second inserts 21, 27 will have identical plan shape and size, in a manner such that the same number of first and second inserts 21, 27 will be inserted inside the cavity 14.
Still more advantageously, the first and the second inserts 21, 27 can be selected among respective series having a higher amount than the maximum number insertable in the cavity 14.
From that described above, it is clear that the mold, the assembly and the method according to the invention attain the pre-established objects and particularly that of obtaining a plurality of push-button units that differ with regard to number and/or distribution and/or type of controls, without requiring the design of an entire mold for each of the push-button unit configurations to be manufactured - hence considerably reducing costs.
Indeed, due to the particular modular configuration of the matrix 17, in order to modify the configuration of the push-button unit 2 it will be sufficient to modify the distribution of the first and/or second inserts 21, 27 inside the cavity 14 or simply substitute one or more first and/or second inserts 21, 27 with further inserts of the same series, without being obliged to change the entire mold 1.
The push-button unit, the tooling and the method according to the invention are susceptible to numerous modifications and variants, all falling within the inventive concept expressed in the enclosed claims. All details can be substituted by other technically equivalent elements, and the materials can be different as required, without departing from the scope of the invention.
Even if the push-button unit, the tooling and the method according to the invention were described with particular reference to the enclosed figures, the reference numbers are used for improving the comprehension of the invention and do not constitute any limitation of the claimed protective scope.

Claims

A method for manufacturing a control push-button unit (2) for electric plants, comprising the following steps:
a) shaping at least one lower half (4) and at least one upper half (5);

b) providing a plurality of electric elements (8, 9,10, 11, 12) comprising contacts;

c) positioning said electric elements (8, 9,10, 11, 12) between said at least one lower half (4) and said at least one upper half (5);

d) coupling said at least one lower half (4) and at least one upper half (5) to form a box-like case (3) designed to enclose said plurality of electric elements (8, 9,10, 11, 12);
wherein said step (a) of shaping said at least one upper half (5) comprises the following steps:

e) providing a mold (1) having a central cavity (14) with a bottom wall (15) and an upper opening (16);

f) inserting a core or matrix (17) in said central cavity (14), which matrix (17) having a shaped lower face (18) substantially facing said bottom wall (15) to define an interspace (20) therewith;

g) inserting a plastic material into said interspace (20) to form said at least one upper half (5);
characterized in that said core or matrix (17) comprises a plurality of substantially prismatic first modular inserts (21, 21', 21",...) designed to realize housing seats (7, 7', 7") for said electric elements (8, 9, 10, 11, 12) and each having a lower surface (22, 22', 22"), said first inserts (21, 21', 21") being appropriately positioned into said cavity (14) with said lower surfaces (22, 22', 22") defining the lower face (18) of said core or matrix (17).
Method as claimed in claim 1, characterized in that said core or matrix (17) further comprises a plurality of substantially prismatic second inserts (27, 27', 27",...) having a shaped upper surface (28, 28', 28",...).
Method as claimed in claim 2, characterized in that each of said second inserts (27, 27', 27",...) is inserted into said cavity (14) with the respective shaped upper surface (28, 28', 28",...) facing the shaped lower surface (22, 22', 22",...) of a corresponding first insert (21, 21', 21",...) to define a portion of said interspace (20).
Method as claimed in claim 3, characterized in that said first and second inserts (21, 21', 21",...; 27, 27', 27",...) are selected among respective series having a higher amount than the maximum number of first and second inserts (21, 21', 21",...; 27, 27', 27",...) insertable at the same time into said cavity (14).
A tooling for manufacturing a control push-button unit (2) for electric plants, wherein the push-button station (2) comprises a box-like case (3) made by at least one lower half (4) and at least one upper half (5), reciprocally couplable, and wherein said at least one upper half (5) has a closing wall (6) provided with seats (7, 7', 7",...) for housing a plurality of electric elements (8, 9, 10, 11, 12) comprising contacts, which tooling comprising at least one mold (1) for forming said at least one upper half (5), said mold (1) having:
- a containment portion (13) with a central cavity (14) having a bottom wall (15) and an upper opening (16);

- a core or matrix (17) insertable into said cavity (14) and having a shaped lower face (18) designed to be faced to said bottom wall (15) to define therewith an interspace (20) designed to be filled with a plastic material to form said at least one upper half (5);
characterized in that said matrix (17) comprises a plurality of first modular inserts (21, 21', 21",...) each having a lower surface (22, 22', 22",...) defining a portion of said lower face (18) of said matrix (17) and complementarily shaped with respect of said housing seats (7, 7', 7",...).
Tooling as claimed in claim 5, characterized in that said cavity (14) extends along at least one longitudinal direction (X), said first inserts (21, 21', 21",...) being designed to be housed into said cavity (14) in longitudinally offset positions according a plurality of combinations designed to define corresponding shapes for said interspace (20) and corresponding distributions for the respective housing seats (7, 7', 7",...) for the electric elements (8, 9,10, 11, 12).
Tooling as claimed in claim 6, characterized in that said upper opening (16) of said cavity (14) is substantially rectangular-shaped with predetermined length (1) and width (w) along respectively said longitudinal direction (X) and a first transverse direction (Y) orthogonal thereto, said first inserts (21, 21', 21",...) being substantially prismatic with at least one first dimension (d₁) substantially equal to said width (w) of said upper opening (16).
Tooling as claimed in claim 7, characterized in that each of said first inserts (21, 21', 21",...) is designed to be arranged longitudinally side-by-side and into contact relationship with at least one further of said first inserts (21, 21', 21",...), said first inserts (21, 21', 21",...) having respective second dimensions (d₂) sized to define a matrix (17) having length substantially equal to that of said upper opening (16).
Tooling as claimed in any claim 6 to 8, characterized in that said bottom wall (15) is formed by a plurality of second inserts (27, 27', 27",...) having respective shaped upper surfaces (28, 28', 28",...).
Tooling as claimed in claim 9, characterized in that each of said second inserts (27, 27', 27",...) is alignable with a corresponding first insert (21, 21', 21",...) along a second transverse direction (Z) orthogonal to said upper opening (16) to define pairs of transversally aligned first and second inserts (21, 27; 21', 27'; 21", 27";...) having respective lower and upper surfaces (22, 28; 22', 28'; 22", 28";...) delimiting a respective longitudinal portion of said interspace (20).
Tooling as claimed in any claim from 6 to 10, characterized in that said containment portion (13) comprises at least one removable side portion (29) defining a lateral access to said cavity (14) for inserting by longitudinal sliding said first and/or second inserts (21, 21', 21",...; 27, 27', 27",...).
A push-button unit (2) for controlling electric plants, comprising:
- a box-like case (3) with at least one lower half (4) and at least one upper half (5) reciprocally couplable;

- a plurality of electric elements (8, 9, 10, 11, 12) comprising contacts and housed in said box-like case (3);

- wherein said at least one upper half (5) has a closing wall (6) provided with seats (7, 7', 7",...) for housing said electric elements (8, 9, 10, 11, 12);
characterized in that said at least one upper half (5) is made by the method according to one or more of claims 1 to 5 and/or by a tooling according to one or more of claims 6 to 11.