US3718886A

US3718886A - Connection plug for a current supply rail

Info

Publication number: US3718886A
Application number: US00042257A
Authority: US
Inventors: H Hoffmeister
Original assignee: Nokia Oyj
Current assignee: Nokia Oyj
Priority date: 1969-05-31
Filing date: 1970-06-01
Publication date: 1973-02-27
Anticipated expiration: 1990-02-27
Also published as: ES380959A1; BE751013A; SE361105B; AT311457B; NO130804C; NO130804B; GB1305638A; FI47237B; DE2002433A1; JPS5218920B1; DE1927940A1; FR2043864A1; FI47237C; NL7007753A; CH509680A; AU1576370A; DK127088B

Abstract

A CONNECTION PLUG IS PROVIDED FOR A CURRENT SUPPLY RAIL. THE PLUG COMPRISES CONTACT SPRINGS ACTUATED BY A CONTROL SHAFT BETWEEN A PROTRUDING CONTACT POSITION AND A RETRACTED INOPERATIVE POSITION. THE CONTROL SHAFT IS FORMED WITH GUIDING SURFACES ANGULARLY DISPLACED WITH RESPECT TO EACH OTHER SO THAT THE CONTACT SPRINGS ARE SELECTIVELY ACTUATED AND BROUGHT TO PROTRUDING CONTACT POSITION BY THE CONTROL SHAFT.

Description

Feb. 27, 1973 H. HOFFMEISTER 3,713,835

CONNECTION PLUG FOR A CURRENT SUPPLY RAIL I '2 Sheets-Sheet 1 Filed June 1, 1970 27, 1973 H. HOFFMEISTER 3, 18,

CONNECTION PLUG FOR A' CURRENT SUPPLY RAIL Filed June 1, 1970 2 Sheets-Sheet z p 1' Ail W5 F/G./6 0(5) F7677 1(5) F/CMB m5) F/Gi m5) United States Patent 3,718,886 CONNECTION PLUG FOR A CURRENT SUPPLY RAIL I-Iansmartin Hoffmeister, Ludenscheid, Germany, assignor to fly Nokia All Finnish Cable Works, Helsinki, Finland Filed June 1, 1970, Ser. No. 42,257 Claims priority, application Germany, May 31, 1965 P 19 27 940.4 Int. Cl. H01r 9/00 U.S. Cl. 339-21 R 9 Claims ABSTRACT OF THE DISCLOSURE A connection plug is provided for a current supply rail. The plug comprises contact springs actuated by a control shaft between a protruding contact position and a retracted inoperative position. The control shaft is formed with guiding surfaces angularly displaced with respect to each other so that the contact springs are selectively actuated and brought to protruding contact position by the control shaft.

The invention relates to a current connecting plug which can be inserted into the opening of an essentially U- shaped current supply rail provided on its side walls with at least three bare conductors and preferably one bare ground conductor and which is provided with contact springs and fastening springs and a longitudinal, in relation to the current supply rail, control shaft which displaces the contact springs against the conductors and the fastening springs in recessed spaces of the current supply rail by means of guide surfaces.

Such plugs are used for supplying current to a consumer apparatus, usually lighting apparatus, which can be directly supported by the plug. When the plug is to be inserted into the opening of the rail, the control shaft must be adjusted to a 0 position; thereafter the shaft is adjusted to its connecting position, in which the ends of the contact and fastening springs protrude from the walls of the plug and assume their operating positions. Thus, there are only two different positions for the turning movement of the control shaft. If the current supply rail has two conductors on each of its interior sides and possibly a fifth conductor on the bottom wall, it would be necessary, e.g. in order to obtain three separate current circuits that can be utilized independently, to connect the corresponding wiring in the plug, at the moment of inserting the plug in the rail, to the supply terminals of the corresponding contact springs. Consequently, the wiring corresponding to the earlier used circuit must be disconnected in the plug and the Wiring corresponding to a newly desired circuit must be connected in the plug each time it is desirable to utilize another circuit of the three possible ciricuits. This connection work is quite inconvenient. The same need for such current supply rails appears at shops, museums and similar applications if a consumer apparatus is to be capable of being rapidly exchanged from one wiring group to another.

The invention is based on the object of providing a plug so that all the current consumer apparatus will have their conductors permanently connected to the associated plug in advance and so that solely by switching the control shaft to another position will it be possible to obtain instantly a recoupling to another ciricuit.

The invention achieves this objection so that the guide surfaces of the control shaft are positioned angularly with respect to each other so that the contact springs actuated by said guide surfaces are selectively displaced in at least two contact positions with the corresponding con- 3,718,885 Patented Feb. 27, 1973 ductors when the control shaft is turned from an inoperative position. Hereby it is achieved that by selectively turning the control shaft to one of its operating positions it is instantly possible to recouple the plug from one circuit to another.

If such a plug is fitted with a bar-like component arranged so that it is longitudinally mobile against a spring for advance touching of the ground conductor, in a favorable embodiment, the bar like component prevents the turning of the control shaft in the off-position (0). This insures free insertion of the plug into the current supply rail, because all the contact springs are still in the retracted initial position.

It is an advantageous form of solution whereby the bar-like component has in a central extension an elongated hole with a groove recess for the control shaft passing through the hole and for the control shaft, which has a projecting part at this point, to catch in the off position (0) under the influence of a spring, preferably a compression spring. The arrangement of the recess and the projecting part can, of course, also be otherwise.

In order that the plug should not be accidentally inserted into the opening of the current rail in a position turned measures are taken in order to prevent this by mechanical means. Therefore it is proposed that a projecting non-interchangeability part penetrating into a bottom groove in the current rail be arranged at the end wall next to the conductors at the leading end of the cross bar.

In order .to reduce the construction length of the plug and of the control shaft and, yet, maintain sufficient width of the hook-formed fastening springs directed outwardly, which springs serve exclusively for fastening the plug in the current supply rail, it is proposed that onesided cuttings be made in both the flat fastening springs at opposite sides of their center parts and that corresponding narrow guide surfaces be arranged on opposite sides of the control shaft axially moved one past the other, each of which guide surfaces is to be followed by another guide surface covering about 270 for maintaining the fastening of the plug in the other switch positions. As far as the contact spring for touching the conductor is concerned, this contact spring will maintain the conducting connection in all the three on-positions, which is obtained so that a relatively narrow control surface on the control shaft is followed by a ring groove covering about 270 so that the contact spring concerned corresponding to the conductor is maintained in connection in all the other three on-positions.

The three contact springs for the conductors are conductively connected to each other and consequently have only one wire connecting terminal. Then the control shaft is turned until one of these contact Springs comes to lie on the corresponding conductor. The formation of a phase short circuit must be avoided. For this purpose, the contact springs affected by the control shaft and control surfaces for the conductors are designed so as to remain under such a strong pre-stress that they aim at strong contact with the corresponding conductors as soon as the supporting control surfaces are retracted from the range of the springs by means of turning the control s a t.

It is important that, when the control shaft is turned into its different switch positions, the contact springs are on no occasion left alone, i.e. to their spring force or pre-stress, but that they are, by appropriate design of the contact springs and of the cams of the control shaft, pressed by sufficient contact pressure from the central rest position against the conductors and, on the other hand, later again by force brought back to the mid-position.

In one embodiment, this is solved so that the contact springs for the conductors are in their central part designed as a cage surrounding the control shaft, the inner walls of which cage are in all the four switch positions in touch with the control shaft, and this touch prevents any spontaneous movement of the contact springs, so that it is also guaranteed that the projecting contact of the contact spring touches the conductor with a strong contact pressure, carries out a forced breaking movement of specified length and insures that no projecting parts of contact springs prevent the insertion or removal of the plug.

In a preferred embodiment, the construction length of the device is shortened by the width of one contact spring in the longitudinal direction of the control shaft by combining two springs as one unit. These two metallic, correspondingly bowed strips are, for this purpose, joined together on both sides of the cage by means of riveting or by other similar means. The control cam of symmetrical triangle form is arranged on the control shaft eccentrically.

As far as the contact spring for touching the other phase is concerned, this spring having only one contact end pointing at this conductor, the strip-like contact spring is in the central cage area firmly connected with a shorter handle-like metal strip by means of riveting or similar means, whereby this shorter metal strip is in the cage area placed aside from the swinging area of the contact spring and the control shaft has two adjoining cams for forcible moving of this contact spring in all the four switch positions, out of which earns a half-circle-shaped one controls one part of the cage, whereas a drop-formed, immediately adjoining cam, by and large perpendicular in relation to the direct section of the former cam, controls the other part of the cage.

In the drawings in which the subject matter of the invention is illustrated by way of two embodiments:

FIG. 1 shows an end view of the connecting plug of the first example of embodiment,

FIG. 2 shows a side view of the same,

FIG. 3 shows a section of the body with a view of the blocking device of the control shaft, functioning as the ground conductor,

FIGS. 4 to 9 show the plug inserted into the opening of the current supply rail with the control shaft still in the position, and more specifically,

FIG. 4 shows the ground conductor in its retracted position eliminating the blocking of the control shaft,

FIG. 5 shows the mechanical fastening of the plug in the retracted position and (broken lines) in its later projecting end position in the three switch positions;

FIGS. 6 to 9 show side views of the four contact springs for the conductors;

FIGS. 10 and 11 show the two fastening springs of FIG. 2 alone;

FIG. 12 shows a side view of the plug body of the second example of embodiment, whereby the side will is broken away at the contact spring section;

FIG. 13 shows the switch Wheel of the control shaft in a front view;

FIG. 14 shows a vertical section of FIG. 12 through the double-acting contact spring;

FIG. 15 shows this contact spring alone in a 90 turned side view;

FIGS. 16 to 19 show a vertical section of FIG. 12 in the area of the other contact spring for one conductor;

FIG. 20 gives a perspective view of a component of the control shaft in the control area of FIGS. 16 to 19; and

FIGS. 21 and 22 show two views of this spring alone at angles differing from each other by 90.

In the drawing, the U- or H-shaped current supply rail, 1 consists of metal or plastic material. In the bottom web of the rail there is a bare ground conductor E. In each of the side webs, there are on strips of insulating material the bare conductors R, S, T, Mp (FIG. 4). A turnable control shaft 3 of insulating material is fitted to the walls of the plug body 2 that run transverse in relation to the longitudinal direction of the rail 1. At one end of the shaft there is a turning handle 3 (FIG. 1). This shaft 3 serves for the controlling of the four flat contact springs 6 FIGS. 6-9 with terminals for the conductors Mp, R, S, T, whereby the terminal ends of the three contact springs 6 for the conductors R, S and T are interconnected conductively. The two conductor wires of a current consuming device carried by the plug, not shown in the drawing, are connected to the terminal of the contact spring 6 (Mp) on one hand and to the terminal of the contact springs 6 (R, S, T) on the other hand, the contact springs 6 can be switched to any one of the three phase circuits depending on desire and need. Thus, no alteration of the wiring in the plug is necessary any longer.

The metallic bar 4, functioning as the ground conductor, has an extension 4 in the middle with a hole 4 for the passing through of the control shaft 3, which is under tension of a compression spring 4 Moreover, in the hole 4* there is a groove recess 4 so that the compression spring 4 can operate only if the control shaft 3 is in the 0 position, i.e. a projecting part 3' permits the operation. Thus the blocking of the control shaft 3 is automatically relieved when the plug 2 is inserted into the opening of the current rail 1 as soon as the advanced free end 4 of the bar 4 reaches the ground conductor E. If the plug 2 is erroneously inserted into the opening of the current rail 1 in a 180 turned position, the end 4 of the bar 4 meets an empty space in a longitudinal groove 1 in the bottom of the current rail 1 so that the blocking 4 3 is not relieved and therefore turning of the

control shaft

3, 3 remains excluded. A projecting part 2 at the end matches the bottom groove 1 and guarantees an uninterchangeable insertion of the plug to the correct depth.

When the plug 2 is correctly inserted and the control shaft 3 is turned, the guide surfaces 3, one displaced axially from the other, of the control shaft affects the fastening springs 5, also in the same way arranged one adjacent the other, so that they press the springs outwards whereby their ends 5 bent outwardly catch behind the attachments 1 directed inwardly, of the current rail 1. As seen in FIG. 5, the blocking device for the plug 2 remains in operation in any of the three switch positions R, S, T because the fastening springs 5 are supported by the round guide surface 3 covering about 270 of the circular periphery of the control shaft 3. Both of the guide surfaces 33 of the control shaft 3 are arranged so that their angle difference is about 180. Both of the fastening springs 5 and 5 (FIGS. 2, 10 and 11) are in their central area 5 cut to about one half of their width in order to reduce the construction length of the control shaft 3.

The fiat contact springs 6 for the four conductors Mp, R, S, T are controled by the corresponding guide surfaces 3, 3 3 3 3 3 3 3 of the

control shaft

3, 3 Springs 6 are designed in such a way that due to material type and strength, they press themselves against the corresponding conductors Mp, R, S, T to such an extent that the current conductivity is insured. Thus, they are subjected to corresponding pre-stress. The breaking of the current connection when the plug is switched off by means of the

control shaft

3, 3* takes place in any case through the cam control of the

control shaft

3 and 3 which cams lift the springs off the conductors.

The contact spring 6 for the conductor Mp (FIG. 6), due to design of the guide surface 3", 3 of the control shaft 3 at this point, remains switched-on in all the switch positions R, S, T. The contact springs 6 (R) in FIG. 7, 6 (S) in FIG. 8 and 6 (T) in 'FIG. 9 are pressed in only one of the corresponding three on positions R, S, T (FIG. 1) against the corresponding conductors R or S or T when the positions of the guide surfaces 3 3 3 with angle difference between each of them, allow this. In the other switch positions, they are lifted by the 270 circular surfaces 3 3 and 3 against their spring tens'ion off the conductors and are kept retracted so that their free ends freely allow the insertion and removal of the plug 2 into and from the current supply rail 1. The three contact springs 6 for the conductors "R, S and T are interconnected by means of a conductor strip 6', which has only one common terminal 6" for one of the current conductors of the current consumer.

Theoretically it would also be possible to place, on one side wall of the current supply rail 1, two conductors and, on the opposite side wall, one conductor in order to obtain in this way only two wiring groups instead of three. In such a case the ground conductor E can be practically arranged in the side wall of the current supply rail that is fitted only with one conductor.

Further it is possible to utilize the current supply rail itself as the ground conductor, in which case the ground conductor E is left out.

In the second embodiment shown in FIGS. 12 to 22, the body 2 contains the control shaft 3 with its different cams and bears outside an adjusting handle 3* for the adjustment of 4 switch positions, 0, I, II, III. The contact spring serving for alternative touching of the two conductors R, T with its bent contact ends 16 and 26' consists of two spring strips 16 and 26, which form in the middle, by means of corresponding bent portions 16 26, a cage that surrounds tightly a symmetrically even, triangular cam 3 of the control shaft 3. Thus, the two contact springs 16, 26 constitute here a constructional unit firmly bound together by means of rivets 7 at both sides of the cage sides 16 and 26. In order to obtain play-free touching of the inner cage walls, the side faces of this triangular cam 3 are also bowed outwards. The contact springs 16 and 26 are at their lower end fastened to a strip 8. By uniting the two contact springs 16 and 26, the construction length of the body 2 can be shortened by one spring width. What is obtained is that neither

contact spring

16 or 26 can in any position of the switch handle adjust itself automatically. Thus, in an on-position the conductor R or T with good contact touch or it remains exactly in mid-position so that a hinderfree insertion into the current supply rail or removal from the same is insured in the position.

As far as the contact spring 36 for touching the conductor S is concerned, it has only one contact end 36' 'bent towards this conductor but here as well the contact spring is bent outwards in the area of the passing control shaft 3 in order to form a cage in the area 36, while there is a similar, essentially shorter, handle-shaped

spring part

36 and 36 fastened at both ends firmly with part 36 by riveting or equivalent means. The latter spring part is, however, in the central area moved aside in relation to the longer contact spring 36 and 36' (FIGS. 12 and 22). This moving aside has been produced here, because this contact spring is aifected by two immediately adjoining guide cams (FIG. 20) of the control shaft 3 of different shapes, one of which

cams including parts

3 and 3 is generally semi-circular. The other guide cam 3 has a drop-shaped section, the line of symmetry of which runs about perpendicularly in relation to the direct fiat surface 3 of the adjoining guide cam. This causes the position of the contact spring 36, to remain in the switch positions 0, I and III always in the midle area although, due to turning of the control shaft 3, it eventually touches the two guide surfaces by different sections, only in position 11 is the contact spring 36 pressed olf from this mid-position to the left against the conductor S.

What I claim is:

1. A connecting plug which can be inserted into the 8 opening of an essentially U-shaped current supply rail including side walls and at least three bare conductors and at least one bare ground conductor on said side walls, said plug including contact springs and fastening springs and, in relation to the current supply rail, a longitudinally disposed control shaft having guide surfaces and which displaces the contact springs against the conductors and the fastening springs into recessed spaces provided in the current supply rail by means of said guide surfaces, said control shaft having operative and inoperative positions, the guide surfaces of the control shaft being positioned angularly with respect to each other so that the contact springs actuated by the corresponding of said guide surfaces are selectively displaced in at least two contact positions with the corresponding conductors when the control shaft is turned from said inoperative position, said plug further including a bar-like spring biased movable element for obtaining advanced contact with the ground conductor of the current supply rail upon insertion of the plug into the latter, the barlike element preventing the turning of the control shaft from its inoperative position.

2. Plug according to claim 1 comprising a spring and wherein the bar-like element includes a central extension for the control shaft provided with an elongated hole with a blocking recess so that the control shaft which includes a co-operating projecting part can engage the recess in the inoperative position under the action of said spring.

3. Plug according to claim 1 wherein the plug includes an end wall adjacent a protruding end of the bar-like element, said end wall including a projecting part penetrating into a bottom groove provided in the current supply rail.

4. A connecting plug which can be inserted into the opening of an essentially U-shaped current supply rail including side walls and at least three bare conductors and at least one bare ground conductor on said side walls, said plug including contact springs and fastening springs and, in relation to the current supply rail, a longitudinally disposed control shaft having guide surfaces and which displaces the contact springs against the conductors and the fastening springs into recessed spaces provided in the current supply rail by means of said guide surfaces, said control shaft having operative and inoperative positions, the guide surfaces of the control shaft being positioned angularly with respect to each other so that the contact springs actuated by the corresponding of said guide surfaces are selectively displaced in at least two contact positions with the corresponding conductors when the control shaft is turned from said inoperative position, said plug further comprising two hook like fastening springs for locking the plug in the current supply rail and arranged on opposite sides of the control shaft and, directed outwards, each fastening spring being blockable by means of a guide surface on the control shaft into recessed spaces of the current supply rail, each fastening spring including a central part which is recessed on one side, the control shaft being provided with corresponding opposite, guide surfaces axially displaced in the axial direction of the control shaft, each said guide surface cooperating with a guide surface extending about 270 around the control shaft for maintaining said locking of the plug in the rail.

5. A connecting plug which can be inserted into the opening of an essentially U-shaped current supply rail including side walls and at least three bare conductors and at least one bare ground conductor on said side walls, said plug including contact springs and fastening springs and, in relation to the current supply rail, a longitudinally disposed control shaft having guide surfaces and which displaces the contact springs against the conductors and the fastening springs into recessed spaces provided in the current supply rail by means of said guide surfaces, said control shaft having operative and inoperative positions, the guide surfaces of the control shaft being positioned angularly with respect to each other so that the contact springs actuated by the corresponding of said guide surfaces are selectively displaced in at least two contact positions with the corresponding conductors when the control shaft is turned from said inoperative position, a relatively narrow guide surface constituting one of the guide surfaces of control shaft and a ring groove extending 270 around said shaft and adjacent said narrow guide surface in such a way that the corresponding contact spring for the conductor is brought into contact with one of the conductors in all other operating positions of the shaft.

6. A connecting plug which can be inserted into the opening of an essentially U-shaped current supply rail including side walls and at least three bare conductors and at least one bare ground conductor on said side walls, said plug including contact springs and fastening springs and, in relation to the current supply rail, a longitudinally disposed control shaft having guide surfaces and which displaces the contact springs against the conductors and the fastening springs into recessed spaces provided in the current supply rail by means of said guide surfaces, said control shaft having operative and inoperative positions, the guide surfaces of the control shaft being positioned angularly with respect to each other so that the contact springs actuated by the corresponding of said guide surfaces are selectively displaced in at least two contact positions with the corresponding conductors when the control shaft is turned from said inoperative position, the contact springs for the conductors being affected by the control shaft and by the guide surfaces and being positioned under such a pre-stress that they are urged against respective of said conductors forcibly as soon as the supporting guide surfaces are released from engagement with said springs upon turning of the control shaft.

7. A connecting plug which can be inserted into the opening of an essentially U-shaped current supply rail including side Walls and at least three bare conductors and at least one bare ground conductor on said side walls, said plug including contact springs and fastening springs and, in relation to the current supply rail, a longitudinally disposed control shaft having guide surfaces and which displaces the contact springs against the conductors and the fastening springs into recessed spaces provided in the current supply rail by means of said guide surfaces, said control shaft having operative and inoperative positions, the

guide surfaces of the control shaft being positioned angularly with respect to each other so that the contact springs actuated by the corresponding of said guide surfaces are selectively displaced in at least two contact positions with the corresponding conductors when the control shaft is turned from said inoperative position, the contact springs for the conductors being formed in their middle parts as a cage enclosing the control shaft, the inner walls of said cage being in all operating positions of said shaft in engagement with the control shaft.

8. Plug according to claim 7, wherein the contact springs for contacting selected of the conductors comprise two metallic bent strips which are firmly interconnected on both sides of the cage and the control shaft is of essentially triangular shape with outwardly bowed guide surfaces.

9. Plug according to claim 7, wherein one of the contact springs for contacting one of the conductors is in its central cage area firmly united with a shorter, handleshaped metal strip whereby said shorter metal strip is displaced sidewards from the swinging zone of the contact spring and wherein the control shaft is formed with two adjoining cams Q for positive movement of said one con tact spring in all operating positions of said shaft whereby one cage part is guided by semi-circular cam and the other cage part is guided by an immediately adjoining dropshaped cam extending approximately perpendicularly with respect to the surface of said first cam.

References Cited UNITED STATES PATENTS 3,613,041 10/ 1971 Routh et al 33921 R 3,559,146 1/1971 Valtonen 339-21 S 3,503,032 3/1970 Routh et al. 33914 3,496,518 2/1970 Neumann et a1. 33921 R MARVIN A. CHAMPION, Primary Examiner R. A. HAFER, Assistant Examiner