EP0195879A1

EP0195879A1 - Electrical terminal box for cookers and the like

Info

Publication number: EP0195879A1
Application number: EP85830197A
Authority: EP
Inventors: Bruno Gelati
Original assignee: Elettro Gibi SpA
Current assignee: Elettro Gibi SpA
Priority date: 1985-03-25
Filing date: 1985-07-26
Publication date: 1986-10-01
Also published as: ES288987Y; IT8521218V0; ES288987U

Abstract

An electrical terminal box (1) has a casing (2) of insulating material with cavities (5) for receiving electrical terminals (6). The electrical terminals are composed of conductive material having a central portion (8) with a through hole (9) through which can be passed a screw (21) to be engaged in a threaded nut retained in the connecter body (7) by lateral wings (10) from which project connecter blades (12). When the connecter assembly is introduced into the cavity (5) the head (21a) of the screw (21) is in alignment with a respective access opening (22) in the casing body (2), which is smaller in diameter than the head (21a) to prevent removal of the screw, and the terminal assembly (6) is retained in position in the casing (2) by snap engagement of a resilient tongue (13) on one of the wings (10) into a cooperating detent (14) in the side wall of the cavity (5) in the casing (2).

Description

The present invention relates to an electrical terminal box, particularly suitable for cookers and the like.
Electrical terminal boxes are generally formed with a casing or outer body, made of electrically insulating material such as plastics or the like, within which are housed the individual terminals which, in the most usual form of construction, are each constituted by a contact body to which the various conductors can be connected, usually by means of rlamping screws, the heads of which are positioned outside the said body, possibly in protected zones, so that such screws can, if they become loosened and unscrewed, come away from the contact body and be lost.
This fact creates certain problems in that during manufacture of the terminal box it is necessary to tighten these screws down into the associated threaded seats, which may be constituted by a nut or the like, and the screws themselves must then be loosened and unscrewed upon installation of the terminal box on the electric cooker or whatever electrical utiliser appliance the terminal box is to be fitted. This causes, in practice, a duplication of work, that is to say a screwing up operation during manufacture, and an unscrewing operation during installation, which influences both the production costs of the terminal box itself and the subsequent installation costs.
Another disadvantage resides in the fact that to effect the connection of the earth conductor it is necessary to fit a wire which is connected to the body or casing of the electrical appliance and which is then fixed to an earth terminal of the terminal box.
The present invention seeks to overcome the above listed disadvantages by providing a new type of electrical terminal box suitable for cookers and the like, which will allow the possibility of considerably simplifying the assembly operations of the terminal box during production, whilst also allowing it to have locking screws for the wires which cannot be lost, that is to say which cannot become detached from the terminal box even when the screws themselves are completely unscrewed.
According to the present invention, therefore, there is provided an electrical terminal box suitable for electric cookers and the like, comprising an outer casing in electrically insulating material, defining a plurality of cavities housing terminals for the connection of electrical conductors characterised in that the terminals are snap-engageable into the said cavities and include screws for clamping electrical conductors to respective terminals which screws are held captive in the cavities.
In a preferred embodiment of the invention the positioning of the wires upon wiring up the terminal box can be facilitated by the structure of the box, thus reducing the time taken to install an appliance to which the terminal box is fitted.
Likewise, embodiments of the invention can be formed which offer the advantage that the operations required for earthing the electrical utiliser appliance to which the box is fitted can be performed in an extremely rapid and speedy manner without having to have recourse to the utilisation of separate electrical wires or the like.
It must be emphasised that the electrical terminal box of the present invention, which is particularly intended for electric cookers and the like, is easily made.starting from elements and materials which are commonly commercially available, and, moreover, is highly competitive from a purely economic point of view.
One embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which:-

Figure 1 is a schematic perspective, partly cut away and partially exploded view of an electrical terminal box made according to the principles of the present invention;
Figure 2 is a perspective view of a contact body of an individual terminal of the terminal box of Figure 1;
Figure 3 is a front elevation of the terminal box of Figure 1;
Figure 4 is a plan view from below of the terminal box of Figure 1;
Figure 5 is a rear elevation of the terminal box of Figure 1;
Figure 6 is a plan view from above of the terminal box of Figure 1; and
Figure 7 is a side view of the terminal box of Figure 1.

Referring now to the drawings, the electrical terminal box shown, which is particularly designed for electric cookers and the like, is preferably adapted to operate with a nominal current up to 40 amps and a nominal voltage of up to 380 volts. The terminal box has an outer casing body 2 made in electrically insulating material and having, as shown, an elongate generally rectangular conformation with two fixing lugs 3, provided with through holes 4, for fixing the terminal box to the metal structure of a cooker or the like.
Within the casing body 2 there are shaped cavities 5 of which there are three in the case of a terminal box for a single phase supply and six in the case of a terminal box for a three-phase supply. The cavities 5 are open at the lower side of the body 2 and into the cavities 5 can be inserted electrical terminals generally indicated with the reference numeral 6, which snap-engage into the interior of the said cavities 5.
As can be seen in Figure 2, the terminals 6 have a contact body generally indicated 7, comprising a central portion 8 with a through hole 9, at the sides of which are provided wings 10 which join, with the interposition of a stepped section 11, to a contact blade 12 for the connection of a connecter terminal or the like. One of the wings 10 has a resilient outwardly projecting tongue 13, which serves for snap-engaging with a cooperating detent on the side of each cavity 5 in such a way as to retain the contact body 7 within the cavity 5 once the contact body has been inserted into the lower open part of the cavity 5 itself.
The zone delimited between the lateral wing 10 and the central portion 8 is shaped to receive a fixing nut 20 which is substantially rectangular in plan form so as to be non rotatable, which has a threaded hole into which a screw 21 engages, which can be introduced through the hole 9 in the central portion of the contact body 7. When the thus assembled contact body and clamping screw is introduced into the cavity 5, the screw head 21a is disposed in alignment with a hole 22 in such a way as to allow access to the head 21a of the screw 21, which has a diameter greater than the hole 22 so that the screw cannot be withdrawn through the hole 22. Upon assembly, therefore, it is not necessary to screw up the screw tightly onto the nut as was previously the case, in the prior art terminal boxes, but it is sufficient to insert the nut between the wings 10 and to engage the screw in the through hole 9, and then snap-engage the contact within the cavity 5, having the certainty that it will all remain in position, not being able to escape from the cavity 5 due to the snap-engagement of the resilient tongue 13; moreover, nor can the screw escape in that its head has a greater diameter than the access hole 22.
On the upper face of the body 2 there are provided apertures 33 for the introduction of conductor wires, disposed substantially in alignment with the section 11 which joins the wings 10 to the contact blades 12, so that it serves as an abutment stop to limit the introduction of the electrical wires, indicated 31, which can thus be easily and rapidly positioned within each terminal.
Moreover, the terminal 6 is provided in correspondence with the earth wire with a projection 40 which is disposed coplanar with one of the lugs 3 in such a way that it is directly in contact with the outer casing of the utiliser appliance to which the terminal box is fitted, thus directly forming the earth connection, which can be made stable by engagement of clamping screws into the holes 41 provided on the projections 40.
The production of the terminal box described above is extremely simple and, in fact, after having made the outer body 2, it is sufficient to snap-engage the terminals without effecting any preliminary assembly of the component parts, in such a way as to house the contact body, the nut and the clamping screw within the cavity having the certainty that none of the parts can escape. Moreover, the projection 40 of the earth contact terminal automatically disposes itself in contact with the outer casing to put the casing of the terminal box itself in contact with the earth.
Another important aspect of the invention is, moreover, constituted by the fact that the screws can never escape from the cavities and, therefore, they are held absolutely captive and facilitate all the connection operations for the electrical wiring operation, which are also facilitated by the fact that the step portions 11 serve, in practice, as abutment stops to limit the introduction of the wires themselves, which are thus always precisely and rapidly positioned.
There is thus made available a terminal box designed for application to electrical cookers, which gives the possibility of significantly facilitating all the manufacturing operations as well as the assembly operations.
In practice, the materials used, as long as they are compatible with the specific use, as well as the shape and dimensions can be different from that described by way of example hereinabove.

Claims

1. An electrical terminal box suitable for electric cookers and the like, comprising an outer casing (2) in electrically insulating material, defining a plurality of cavities (5) for housing terminals (6) for the connection of electrical conductors (31), characterised in that the terminals (6) are snap-engageable into the said cavities (5) and include screws (21) for clamping the electrical conductors (31) in the terminal (6), which screws (21) are held captive in the cavities (5).

2. An electrical terminal box according to Claim 1, characterised in that the said terminals (6) have a contact body (7) with a central portion (8) provided with a through hole (9) and lateral wings (10) each of which has an electrical connection blade (12) joined thereto by a step section (11) each of which lies substantially perpendicular to the plane of the associated wing (10).

3. An electrical terminal box according to Claim 2, characterised in that the region of the terminal body (7) delimited by the wings (10) and the central. portion (8) is shaped to receive a locking nut which can be engaged by a screw (21) which can be introduced through the said through hole (9) in the central portion (8).

4. An electrical terminal box according to Claim 2 or Claim 3, characterised in that the snap-engagement of the terminals (6) into the said cavities (5) is effected by means of a resilient tongue (13) projecting laterally from one of the wings (10) of each terminal body (7) and engageable with a cooperating detent (14) on the side wall of the cavity (5).

5. An electrical terminal box according to any of Claims 2,3 or 4, characterised in that the casing (2) has respective access holes (22) which when a contact body (7) is disposed in a cavity (5) are in alignment with a respective said through hole (9) on the central portion (8) of the terminal body (7).

6. An electrical terminal box according to Claim 5, characterised in that the head (21a) of the screw (21) in the through hole (9) in the terminal body (7) has a greater diameter than the access hole (22) such that it prevents removal of the screw.

7. An electrical terminal box according to any preceding Claim, characterised in that the upper face of the outer casing (2) has holes (30) for the introduction of wires (31) disposed substantially in alignment with the step section (11) of a contact body (7) in an associated cavity, the step section serving as an abutment element for limiting the introduction of the said wires (31) into the holes (30).

8. An electrical terminal box according to one or more of the preceding Claims, characterised in that one terminal (6) of the terminal box has a projection (40) which is disposed coplanar with fixing lugs (3) of the outer casing (2) for fixing to the structure of an electrical appliance.