EP0768737A1

EP0768737A1 - A socket box

Info

Publication number: EP0768737A1
Application number: EP96610037A
Authority: EP
Inventors: Jorn Holmstrom
Original assignee: LK AS
Current assignee: LK AS
Priority date: 1995-10-16
Filing date: 1996-10-07
Publication date: 1997-04-16
Anticipated expiration: 2016-10-07
Also published as: DE69612936T2; DE69612936D1; ATE201536T1; DK116795A; EP0768737B1; DK172045B1

Abstract

A socket box provided with a housing comprising at least two parts (12,14) receiving a plurality of rotatable socket inserts, each provided with a plurality of pin bushings (25) and adapted to receive a plug with pins (50), and provided with flexible, moveable, continuous connecting wires (38,40,42) electrically interconnecting corresponding pin bushings (25) and inlet terminals with the same phase. The connecting wires (38, 40, 42) are of such a length that the length of the connection between the pin bushings (25) of two socket inserts exceeds the direct distance so as to allow the individual socket inserts (16,20) to rotate independently of each other. The flexible, movable, continuous connecting wires (38, 40, 42) have an oblong cross-section are attached only to the inlet terminal and each of the rotatable socket inserts. The flat, insulated conductors enable a particularly simple design of the parts of the housing, which reduces the manufacturing costs.

Description

The invention relates to a socket box provided with a housing comprising at least two parts receiving a plurality of rotatable socket inserts, each provided with a plurality of pin bushings and adapted to receive a plug with pins and provided with flexible, moveable, continuous connecting wires electrically interconnecting corresponding pin bushings and inlet terminals with the same phase, said connecting wires being of such a length that the length of the connection between the pin bushings of two socket inserts exceeds the direct distance so as to allow the individual socket inserts to rotate independently of each other.
A socket box of this type is known from DE 4.309.453 C1. Socket boxes provided with rotatable or diagonal socket inserts are furthermore known from DE 3.902.124 C2 which discloses a socket box provided with sockets in one end face, each socket being rotatable and adapted to adopt four different positions and the box having fixed conductor rails and each socket being provided with contact flaps, each of which having contact with one of the rails. DE 4.125.604 A1 discloses a socket box having diagonal socket inserts which are supplied with power from fixed conductor rails.
DE 3.641.153 A1 discloses a socket box having contact rails provided with bushings and contacts to earth. The contact rails are power supplied in a conventional manner via a soft, flexible wire. In order to obtain the optimum number of socket inserts relative to total volume of the box, socket inserts are provided on both sides of the box. AT 374.977 discloses a socket box with socket inserts inclined relative to a symmetry line for the socket box.
The object of the invention is to provide a socket box of the above type which is more flexible than hitherto known and which can be manufactured on automatic machines to very high degree so as to reduce the price of manufacture.
The socket box according to the invention is characterised in that it is provided with flexible, movable, continuous, non-fixed connecting wires having insulated conductors and an oblong (i.e. non-circular) cross-section, said conductors being substantially attached only to the inlet terminals and each of the rotatable socket inserts, and that at least a considerable portion of the non-fixed wires are arranged with their wide sides substantially perpendicular to the bottom face of the housing.
As a result, a high flexibility in the rotatable inserts is obtained at the same time as it is possible to manufacture the socket box with particularly simply shaped parts of the housing. Thus, the costs of manufacturing tools are reduced and the manufacture as well as the assembly of the continuous, insulated conductors are suitable for a high degree of automation. As a result the production costs are reduced, correspondingly. By employing a wire with a non-circular cross-section a larger contact surface as well as an improved cooling are obtained. As a result a smaller cross-section and an increased flexibility may be obtained.
Preferably, the insulated, flexible connecting wires are in conducting contact with the retaining means, such as casings forming part of the pin bushings of the socket inserts, the connecting wires being stripped on at least a portion contacting the casing. A chain of contacts is thus established which is particularly easy to mount in the socket.
The invention further relates to a connecting wire formed as a chain of contacts for mounting in a socket box. The connecting wire is characterised in that it comprises a conducting, flat, insulated ribbon of a width of approximately 2 to 10 mm, preferably approximately 7 mm and of a thickness of about 0.1 to 0.5 mm, and that it is stripped in substantially constant or periodic intervals so as to provide contact areas.
The invention is explained in greater detail below with reference to the accompanying drawings, in which

Figure 1 is a perspective view of a preferred embodiment of a socket box according to the invention,
Figure 2 illustrates the same in dismounted state without wires,
Figure 3a is a diagrammatic illustration in vertical projection of an example of a wiring system in an embodiment of a socket box according to the invention with "Danish earth",
Figure 3b is a diagrammatic illustration in vertical projection of a second example of a wiring system in a second embodiment of a socket box according to the invention,
Figure 4 is a section of Figure 3b on a larger scale,
Figure 5 is a perspective view of a socket insert on a larger scale,
Figure 6 is another section of Figure 4 on a larger scale illustrating an embodiment of a pin bushing,
Figure 7 illustrates a joint between a spring, a conductor and a contact plate,
Figure 8 illustrates a pin bushing/casing having a spring, a conductor and a contact plate,
Figure 9 is a side view of a socket box according to the invention with plug connections in both ends,
Figure 10 is a top view of a preferred embodiment of a socket box according to the invention,
Figure 11 is a top view of a preferred embodiment of a bottom part for the socket box according to the invention shown in Figure 10,
Figure 12 is a sectional view through the socket box shown in Figure 10,
Figure 13 is a preferred embodiment of a rotatable disc,
Figure 14 illustrates the same rotatable disc in a sectional view along the line A-A in Figure 13,
Figure 15 a second embodiment of a pin bushing/casing having a spring, a conductor and a contact plate,
Figure 16 illustrates a second embodiment of the contact plate,
Figures 1, 2, 10, 11 and 12 illustrate an example of a preferred embodiment of a socket box according to the invention having a housing - either in an assembled or in in a separated state. The socket box is provided with three inserts. It may have four, five, six or even more inserts.

The socket box comprises an upper part 12 and a bottom part 14, confer Figure 11, and three rotatable inserts, each comprising an substantially circular, cylindrical and optionally slightly conical well 16, a circular rotatable disc 20 and two or three pin bushings 25. Moreover, the socket box is provided with one or several connecting terminals 36 for insertion of a live wire (phase, neutral + possibly earth). The bottom part 14 is preferably provided with inclined walls, confer Figure 12.
As illustrated in Figure 3a and 3b, corresponding pin bushings 25 in each socket insert 16 are connected by means of zig-zag, non-fixed, flexible, continuous, insulated wires 38, 40, 42. In Figure 3, each conductor is indicated by means of dotted lines inside the insulating material. The cross-section of the conducting wire is oblong or in other words non-circular so inter alia as to enhance the flexibility in one direction. The connecting wire 38, 40, 42 is preferably flat and formed like a ribbon.
The wires 38,40,42 are of such a length that the connection between the pin bushings of two socket inserts 16 exceeds the direct distance considerably so as to allow the socket inserts 16 to rotate independently of each other. This also applies to the length of the connection between an inlet terminal and the pin bushings of the adjacent socket insert. The rotatable socket inserts 16 are advantageous in that they facilitate the mounting of the individual plugs in the socket box.
The socket box is provided with a phase conductor and a neutral conductor and preferably also with a earth conductor. The terminals of the earth conductor can be formed as shown in Figure 3a, i.e. "Danish earth", but may alternatively be a "shuko" type , a French type or another known type.
The upper part 12 and the bottom part 14 are preferably moulded plastic shells. Three slots are provided in the upper surface of the upper part 12, each having a well 32 to receive a socket insert 16, 20, 25.
The bottom part 14 is provided with one or several connection for power supply power to the conductors of the socket, such as terminals or as shown in Figures 1 and 2, a plug connection 36 in one end or in both ends as shown in Figure 9. Slop forms may be provided in the bottom part 14 and/or optionally in the side walls of the upper part 12.
Figures 4 and 5 illustrate a single socket insert on a larger scale comprising a socket well 16 having three pin bushings 25 (only two pin bushings 25 are shown in Figure 5) mounted on a rotatable disc 20 preferably adapted to lockingly engage the socket well 16 such that the socket insert forms an assembled unit. Optionally, the well body 16 and the rotatable disc 20 can be moulded integrally.
In a preferred embodiment the rotatable insert comprises the socket well 16 and the associated rotatable disc 20 and pin bushings 25 arranged between 1) the inner edge of a circular slot/opening 32 in the upper part 12 co-acting with a circumferential recess 30 on the socket well 16, and 2) a rotatable member in the bottom of the housing of the socket box such as a centrally arranged bottom tab 34 (confer Figures 2 and 11) in the bottom part 14 co-acting with a corresponding bearing means such as a formed portion or cavity in the centre of the circular rotatable disc 20. The rotatable disc 20 is preferably further supported on its sides by means of supporting means 35, confer Figure 11. However, it is obvious for a person skilled in the art, this rotational arrangement of the socket inserts can be carried out in several ways.
Due to the flexible conductors and the rotatable arrangement of the inserts 16, said inserts can rotate relative to the housing.
In an alternative embodiment (not shown), the substantially cylindrical portion of the well body 16 can be integrally moulded with the upper surface of the housing and thus form a well for receiving a plug. In this embodiment, the engagement between the cylindrical body and the bottom of the well and the rotatable disc 20 is rotatable.
In such an embodiment, the engagement between the lower edge of the cylindrical body is formed as a circumferential bearing supporting and controlling the rotatable disc 20. Such a bearing can be formed in many ways which are obvious for persons skilled in the art and consequently not shown.
The pin bushings 25 are formed as casings or retainers 44 which can be inserted into openings 22, 23, 24 adapted thereto (Figure 5) or slots (Figures 13 and 14) in the rotatable disc 20. The casings 44 may be provided with projections which can engage recesses or notches 26. As illustrated in Figures 12, 13 and 14, one of the casings may advantageously be displaced upwards relative to the other casings, said casing being supported by straight walls 27 on an raised portion of the rotatable disc 20.
A preferred embodiment of a pin bushing 25 is described in the following. The pin bushing shown in Figures 6 and 8 comprises an insulated casing or retainer 44 moulded in plastics housing a preferably U-shaped spring means 46 having two flexible legs. A flexible conductor 38 passes unbroken through the pin bushing 25. The portion of the conductor 38 arranged in the pin bushing 25 comprises a stripped contact area conductingly connected to a contact plate or thrust pad 48 and to said U-shaped spring means 46.
It is obvious to a person skilled in the art that the casing per se or the socket box can be shaped in various ways. It is thus within the scope of the invention to arrange the flexible conductor on the outer surface of the casing in conducting contact with the conducting portions of the casing or the pin bushing.
When using the socket box, i.e. when a plug is inserted into a socket insert and thus a pin 50 into the pin bushing 25, the pin 50 is squeezed between the spring leg 46 and the contact plate 48, whereby a particularly reliable conducting connection through the pin bushing 25 is obtained, especially due to the large contact surfaces as a result of the flat conductor.

Chain of contacts.

The flexible wire has an oblong cross-section, preferably rectangular as shown in Figure 8 or optionally oval shown in Figure 7, and in the preferred embodiment the wire is an insulated, flat wire, optionally a laminated sheet film having a thickness of a few tenths of a milimeter, e.g. 0.1 to 1.0 mm and a width of about 2 to 10 mm, in particular about 0.2 mm x 7 mm resulting in a cross-section of the conductor of about 1.5 mm².
Preferably, the conductor is provided with contact pieces or contact shoes 48 mounted directly on the conductor, e.g. as shown in Figure 6,7,8 and 15 so as to form a chain of contacts. The contact shoe 48 may for instance be provided with projecting lateral member co-acting with the spring means 46, as illustrated in Figure 16.
The conductor may advantageously be contacted in advance and preferably directly in continuation of the manufacture of the flat wire, the individual insulated conductor at constant intervals of about 5 to 10 cm (e.g. 6 cm) being stripped at a subsequent contact area and at least one side being connected with a conducting contact plate (contact shoe) 48. The contact may also be established by means of sealing, rivetting, clipping, gluing with a conducting bond or a similar product. The spring means46 is subsequently squeezed on and finally an insulating housing or casing 44 is mounted such that all electrically conducting parts are enclosed by the insulating casing. Such continuous, flexible and insulated chains of contacts can be produced automatically in considerable lengths which subsequently are cut into the desired lengths and mounted in the socket box.
In a second advantageous embodiment, the contacting is established by assembling the stripped conductor, a contact plate or thrust pad and a spring in a retainer, preferably as shown in Figure 8 by inserting a spring means 46 in a cavity of a retainer 44 and placing the conductor 38 and the thrust pad 48 such that they are retained by the spring load. The retainer 44 housing the spring means 46, the conductor 38 and the thrust pad 48 thus forms a pin bushing 25 on a chain of contacts which subsequently is inserted directly into the socket box, the pin bushings being squeezed into the intended rotatable disc 20 prior to joining thereof with the socket well 16. Such a chain of contacts is particularly advantageous in that it enables a highly automized mounting of the socket.
The predetermined interspace between the contacted portions of the conductor is selected in such a manner that the length of the conductor is sufficient to allow the socket insert to rotate ± 37.5° or 45°, optionally ± 90°.
The flat, insulated wire is further advantageous in that the heat emission to the air through the electric insulation has proved superior to that of an uninsulated conductor, whereby an increased safety or protection against overheating of a conductor in case of an overloading of the conductor is obtained. As a result, the cross-section of the conductor may be reduced in relation to the cross-section of uninsulated conductors.
A considerable advantage of the present socket box is that the chains of contacts are insulated. The requirements for heat and fire safety, insulation and design of the outer parts, i.e. the upper part and the bottom part 12, 14 of plastics, are reduced resulting in substantial savings in materials. Moreover, the socket box is insulated twice rendering an increased safety against contact with the electric parts.
The more simple design is further advantageous in that the tools for the manufacture of the parts can be more simple, as no interior partition walls or fixing means for retaining the conductors are needed as opposed to the conventional sockets, wherein conducting, uninsulated rails are typically fixed in a bottom part.
The manufacture of the socket box according to the invention is suitable for a high degree of automation. The pre-fabricated chain of contacts only has to be cut into suitable lengths with a number of contacts adapted to the number of socket inserts in the particular type of socket boxes; assembled with the pinbushings 25; mounted in the rotatable disc 20, and assembled with the rotatable well 16 to form a socket insert and arranged between the two parts 12, 14 which also are assembled, e.g. by means of screws, nuts or rivetted together, said processes being carried out automatically.
It is obvious that the invention can be varied in relation to the illustrated and described embodiments. The parts of the housing may for instance be divided in another manner, the upper part may as an example be substantially shaped as a cover and/or the bottom part may substantially have a flat bottom, optionally combined with an intermediate third part forming the lateral walls of the socket box.

Claims

A socket box provided with a housing comprising at least two parts (12,14) receiving a plurality of rotatable socket inserts (16,20) each provided with a plurality of pin bushings (25) and adapted to receive a plug with pins (50), and provided with flexible, moveable, continuous connecting wires (38,40,42) electrically interconnecting corresponding pin bushings (25) and inlet terminals with the same phase, said connecting wires (38,40,42) being of such a length that the length of the connection between the pin bushings (25) of two socket inserts exceeds the direct distance so as to allow the individual socket inserts (16,20) to rotate independent of each other, characterised in that it is provided with flexible, movable, continuous, non-fixed connecting wires (38,40,42) having insulated conductors and an oblong (i.e. non-circular) cross-section, said conductors being substantially only attached to the inlet terminals and each of the rotatable socket inserts (16,20), and that at least a considerable portion of the non-fixed wires are arranged with their wide side substantially perpendicular to the bottom face of the housing.
A socket box according to claim 1, characterised in that the insulated, flexible connecting wires (38,40,42) are in conducting contact with retaining means, such as casings (44) forming part of the pin bushings (25) of the socket inserts (16,20), the connecting wires (38,4042) being stripped on at least a portion contacting the retaining means.
A socket box according to claim 2, characterised in that the individual retaining means (the casing 44) comprises or completely or partly circumscribes a contact spring member (46) and a thrust pad or a contact plate (48).
A socket box claim to one or more of the claims 1 - 3, characterised in that the continuous, insulated, flexible wires (38, 40, 42) are formed of insulated conductor ribbons.
A socket box claim to one or more of the claims 1 - 4, characterised in that the conductors (38, 40, 42) are passed through the retaining means (the casings 44).
A socket box claim to one or more of the claims 1 - 5, characterised in that each socket insert comprises a rotatable disc (20) rotatably arranged relative to the housing and provided with openings (22, 23, 24) for mounting of the retaining means (the casings 44) and that the rotatable disc (20) is connected to or adapted to engage a well body (16) having the inner shape of a substantially short cylindrical surface and dimensioned so as to receive a plug.
A socket box according to claim 6, characterised in that the well body is a rotary body (16) rotatably engaging the rotatable disc (20) and rotatably arranged relative to the openings (32) in the upper surface of the socket, the upper edge portion (30) of said body adapted to co-act with the edge portion (32) of a circular slot in the upper surface of the housing, i.e. in the part forming an upper part (12) of the housing.
A socket box according to claim 6, characterised in that the rotatable disc (20) rotatably engages the well body (16) connected to the upper surface of the housing and unable to rotate relative hereto, the well body (16) preferably being integrally moulded with the upper surface of the housing.
A socket box according to claims 6 , 7 or 8, characterised in that the rotatable disc (20) is provided with a bearing means adapted to co-act with a rotary member (34) in the bottom of the housing, i.e. the bottom part (14) of the housing.
A socket box according to one or more of the claims 1 - 9, characterised in that the flat conductors (38, 40, 42) are provided with fixed, interspaced contact pieces (48) and/or contact springs (46).
A connecting wire in form of a chain of contacts for mounting in a socket box according to one or more of the claims 1 - 10, characterised in that it comprises an electrically conducting, flat, insulated ribbon having a width of about 2 - 10 mm, preferably about 7 mm and a thickness of about 0.1 -0.5 mm and that it in substantially constant or periodic intervals is stripped to form contact areas.
A connecting wire according to claim 11, characterised in that the flat conductor (38) on the stripped contact portions is conductingly connected to contact plates (48) and/or contact springs (46).
A connecting wire according to claim 12, characterised in that the contact plates (48) and/or the contact springs (46) are retained by sealing, rivetting, clipping or the like.
A connecting wire according to claim 12, characterised in that the spring (46) and the contact plate (48) are arranged in a retainer (44) dimensioned so as to retain the said parts.