Abstract:
An optical traffic signal column including stacked levels fixed to one another by rotation. The base of each level includes, distributed along its periphery, oblong passages and fixed connectors. The conductors include rods each having two ends angularly offset from one another, and including a common conducting rod and a stage-specific conducting rod. The connector rods are identical and respectively fix the bottom of a conducting rod of the relevant level and the top of the respective conducting rod of an adjacent level, the angular offset between the two fixing points corresponding to that of ends of the conducting rods. The conducting rods are mutually arranged and mounted to effect, from one level to the next level, an essentially identical angular position of the common conducting rods and an angular offset of the stage-specific conducting rods.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a signal column composed of visual, audible or other-type signaling stages fastened in a stacked arrangement, the stages each having a body consisting of a base and of a side wall and conductors providing a connection between a power source and a signaling member housed in the body. 
   DISCUSSION OF THE BACKGROUND 
   Signal columns of this type are known from document FR 2 128 998. The supply conductors described in this document consist of blades comprising a first male connection end and a second female connection end. Homologous conductors situated in stacked stages are placed in series by introducing the male end of one into the female end of the other. The manufacture of such conductors entirely assuming the interconnection function is complicated. Furthermore, in these old columns each stage is supplied electrically by means of two specific conductors, this considerably multiplying the number of conductors at the base of the column. 
   Document EP 755 494 discloses a signal column in which the supply conductors are folded to form a U-shaped bridge at one end and an elbow at their other end. In this way homologous conductors situated in stacked stages are placed in series by elastic application of the elbow of the one with the U-shaped bridge of the homologous conductor of the other. However, this arrangement may result in contact faults because the connection quality is entirely assumed by the shape and elasticity of the conductors. Furthermore, as in the preceding document, each stage of the column is supplied by two conductors, yet the number of these conductors must be limited. 
   In order to limit the number of conductors, there is provided in each stage of the column a common conductor which, by connecting from stage to stage, extends from the lowermost stage to the uppermost stage, and, for each stage, an allocated conductor which originates from the lowermost stage and which does not have to be continued toward the immediately upper stage. The stage-to-stage connection is to this end brought about by means of an angular offset of the connecting points for the conductors, as is described in document FR 2 517 021. The disadvantage is that, if it is desired to give the various stages the same angular assembly position, use must be made of common conductors whose shape differs from that of the allocated conductors. 
   Document DE 100 41 202 describes a signal column having a number of stackable signaling elements. Each element is provided with a light source supplied from electrical conductors extending along its side wall. One conductor is common to all the signaling elements and supplies each of them. Another conductor is specific to the supply of each stage. Each conductor has a first end forming a junction bridge for an adjacent signaling element. The common conductor has the specific feature that it extends vertically along the column, whereas the conductors specific to each signaling element are offset angularly from one stage to the other. The junction bridge of the common conductor takes the form of a knot so that it can extend along this vertical axis. As in document FR 2 517 021, this document proposes using a conductor common to all the stages and specific conductors allocated to each of the stages. The proposed solution therefore makes it possible to limit the number of conductors. However, this solution requires the use of specific conductors whose shape differs from that of the specific conductors, this complicating the manufacturing method and increasing its cost. 
   SUMMARY OF THE INVENTION 
   The object of the invention is to provide a signal column which can be manufactured simply and inexpensively. 
   According to the invention, the signal column is composed of signaling stages, particularly visual signaling stages, which are mounted in a stacked arrangement along a main axis and fastened to one another by rotation, the stages each having a body which comprises a base and a cylindrical wall, and housing a signaling member and conductors which are distributed over the periphery of the body and which extend parallel to the axis so as to provide an electrical connection between a power source and the signaling member, the conductors housed in a stage being conducting rods, the rods housed in a stage comprising a common rod and at least one stage-specific rod. The column according to the invention has the following particular features:
         the common rods are identical to the other rods, and   from one stage to the other, the common rods have a substantially identical angular positioning relative to one another and the specific rods have an angular offset with respect to one another.       

   According to one particular feature, the base has connectors and each connector comprises two fastening points for respectively fastening a first end of a rod of the stage in question and a second end of the respective rod of an adjacent stage. 
   According to another particular feature, the conducting rods each have two ends angularly offset from one another. 
   According to another particular feature, the two fastening points of the connector have an angular offset, this angular offset corresponding to that present between the two ends of a rod. 
   According to one specific embodiment, the conducting rods are in the form of a crank with straight ends, which are oriented along the main axis of the column so as to cooperate via a foot and a head with the respective connectors, and with an intermediate offsetting segment. 
   According to one particular feature, the common rod housed in a stage is arranged with a foot/head angular offset in the opposite direction to the foot/head angular offset of the other rods housed in the same stage. In this way the common rods exhibit identical angular positioning from one stage to the other. 
   According to another particular feature, the connectors are identical for the common rod and the other rods, and each connector extends, between the fastening point for the head of a rod from the lower stage and the fastening point for the foot of the rod of the stage in question, over a distance which is substantially equal to that of the offset between the foot and head of the rod. Thus, the connector can compensate for the angular offset between the two ends of a rod, thereby allowing the common rods to extend parallel to the axis of the column. 
   According to another particular feature, each connector has an element for fastening a first end of the conducting rod of the stage in question and an elastic clip for connecting a second end of the respective conducting rod of an adjacent stage. 
   According to another particular feature, the clip of each connector is oriented so as to be substantially tangential and open toward an oblong passage formed in the periphery of the base of the body. 
   According to another particular feature, the connectors are immobilized on the base. 
   According to another particular feature, each connector is fitted or snapped into an insulating stud molded in one piece with the base of the body. 
   According to another particular feature, the body of the stage has, at the opposite end from the base of the stage, a support provided at its periphery with fastening orifices for rigidly retaining the heads of the conducting rods particular to the stage. 
   According to another particular feature, there is provided in a stage two connection pieces intended for the signaling member particular to the stage, each connection piece having an opening for the passage of the foot of a respective conducting rod. 
   According to another particular feature, the foot of the conducting rod is fitted with contacting both in the fastening orifice formed in the connector and in the opening in the connection piece. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The detailed description which follows with reference to the appended drawings illustrates an embodiment given by way of example. 
       FIG. 1  illustrates a staged signal column in a side view. 
       FIG. 2  schematically shows in enlarged axial section a stage of the column according to the invention. 
       FIG. 3  illustrates on an enlarged scale and in plan view two connectors and the associated rods. 
       FIG. 4  is an exploded view of the ends of a conductor and of the associated connectors. 
       FIGS. 5 to 8  schematically show in plan view the connections made in the various stages of the column shown in  FIG. 1 . 
       FIG. 9  is a partial perspective view of two interconnected stages. 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
   The signal column C illustrated in the figures comprises a number of stacked signaling stages or modules A. As can be seen from  FIG. 1 , the column C extends along a vertical axis X and has four stages A 1 -A 4  fastened to one another, the lowermost stage A 1  being fastened to a pedestal S that ensures passage for the electrical conductors, the uppermost stage A 4  being, for example, capped by a cover. The column may of course have a different number of stages. 
   The body  10  of a stage A i  houses a number of conducting rods  20 . For the sake of clarity,  FIG. 2  shows a single rod of a stage A i . The body  10 , which is of cylindrical or prismatic shape with axis X, has a base  11  provided around its periphery (see  FIGS. 3 and 5  to  8 ) with a number of curved passages  12  and with studs  13  adjacent to these passages and intended to receive connectors  30 . At the opposite end from the base (that is to say towards the top in the figures), the body  10  has a support  14  such as a cap or a frame designed to seat the base of the body  10  of the upper stage A i+1 . The frame  14  has fastening tabs  18  each provided with a retaining orifice  18   a  for the upper end of a respective rod  20  of the stage A i . 
   The base  11  has at its center a signaling member  16  placed or fastened on a mount  17 . The member has to be supplied from two rods  20 , one being a rod  20 A allocated to the member  16  of the stage A i , the other being a common rod  20 C for connecting to the member  16  of each stage. It follows that the “allocated” rod  20 A is not connected to the following (upper) stage A i+1 , whereas the common rod  20 C is connected to the following stage, the same applying to the rods  20 A allocated to the upper stages. A stage A i+1  is fastened to an underlying stage A i  by a limited rotation about the axis X, using guide, stop and locking arrangements which do not form part of the invention and are not represented here. 
   In more detail, each rod  20  is in the form of a crank and comprises an upper part terminated by a head  21 , an intermediate segment  22  determining an angular offset about the axis X, and a lower part terminated by a foot  23 . The angular offset—or the corresponding peripheral distance—is illustrated as a in  FIGS. 4 and 5 . The upper and lower parts of the rod are straight and extend along the axis X, whereas the intermediate segment  22  extends substantially horizontally and tangentially so as to determine the desired angular offset between the foot and the head. The head  21  is fastened in a retaining orifice  18   a  formed in the tab  18  of the frame  14  of the element A, whereas the foot  23  is engaged and retained in the connector  30  situated at the bottom of the body  10  of the element A i . Moreover, the head  21  is presented to an associated connector  30  which belongs to the overlying stage A i+1  so as to be retained in this connector (see  FIG. 4 ). In a variant, the positioning of the head and of the foot in the connectors may of course be inverted at the same time as the function performed by the base  11  and the support  14 . 
   It should be noted that, according to the invention, the common rods  20 C are identical to the allocated rods  20 A. However, whereas the allocated rods  20 A in a stage are all arranged in the same direction (for example head  21  offset in the counterclockwise direction with respect to the foot  23 ), the common rod  20 C is arranged in the opposite direction (for example head  21  offset in the clockwise direction with respect to the foot  23 ). This can be seen in  FIGS. 3 and 5  to  8 . 
   The connector  30  is a conducting metal part which is folded so as to fasten both the foot  23  of a rod of the current stage and, in a detachable manner, the head  21  of the associated rod of the lower stage. The connector has a fastening socket  31  for the foot  23  of the associated rod, this socket being obtained for example by cutting out a mounting pad  32 . The connector  30  opens toward the passage  12  of the elastic branches of a clip  33  forming a housing  34  for a head  21  emerging from the lower stage. Each connector is fitted or snapped into a stud  13  or housing of the base  11  and it is held in position by fastening tabs  35  engaged in holes in the base. 
   As can be seen from the figures, the length of the connector—seen between the housing for the head and the orifice for fastening the foot—is substantially equal to, or of the same order as, the length a of the offsetting segment  22  of the rod  20 . In other words, it is possible, when assembling the stage A i+1  on the stage A i  by pivoting, for this offset to be taken up peripherally. The heads  21  of the common rods  20 C of the various stages are therefore in the same angular position. The heads  21  of the “allocated” rods are by contrast mutually offset from stage to stage by an angle corresponding to  2   a.    
   For the purpose of supplying the member  16  of the stage A i  (see  FIGS. 5 to 8 ), there is provided in the body  10  of the stage two connection pieces  36  which extend substantially radially between a connector  30  and a respective terminal of the member  16 . Preferably, the piece  36  simply consists of a contact blade provided with an orifice  37 . The foot  23  of the associated rod passes through this orifice  37  with contacting between the rod and connection piece. The piece is thus positioned on the cut-out socket  31  of the connector  30  which houses the foot  23 . It is additionally held in place by being force-fitted into a lug  19  of the base  11  (see  FIG. 9 ). 
   It should be pointed out that the two connection pieces  36 A,  36 C (see  FIGS. 5 to 8 ) particular to a stage are respectively connected to a rod  20 A allocated to the stage and to a common rod  20 C. Thus, the stage A 1  ( FIG. 5 ) has one common connector and four other connectors (one for A 1  and the other three for A 2 , A 3 , A 4 ), the stage A 2  has one common connector and three other connectors (one for A 2  and the other two for A 3 , A 4 ), the stage A 3  has one common connector and two connectors (for A 3  and A 4 ), the stage A 4  has one common connector and one designated connector. The connectors associated with the rods  20 A,  20 C are all identical. 
   The elements of the column described are fitted in the following way. The connectors  30  are introduced into their respective studs  13 , are fastened via their tabs  35 , then the two connection pieces  36 A,  36 C of the stage are centered on the pad  32  of the respective connectors  30 A,  30 C. The feet  23  of the rods  20  are then inserted with force into the sockets  31  to make contact with the connectors, whereas the heads  21  are fitted into the orifices  18   a  in the tabs  18  to provide reliable positioning. The upper stage A i+1  is placed by its base  11  on the frame  14  of the stage A i  in such a way that the head  21  of the rods  20  is engaged in the respective passage  12  without entering the clip  33 . The upper stage is then rotated about the axis X (horizontal arrow in  FIG. 2 ) so that the heads  21  advance into the respective passages  12  until they enter the clips  33 . On completion of the rotation, each head  21  is maintained in its housing  34 , with the result that the desired connection between the poles of A i  and the corresponding poles of A i+1  is ensured. Since the common rod  20 C is offset tangentially in the opposite manner to the other rods  20 A, and since the length of the connector  30  is equal to the tangential offset a provided by the segment  22  of the rod, the head  21  of the rod  20 C of the stage A i  is in the same angular position as the head  21  of the rod  20 C of the stage A i−1 . By contrast, the head of a rod  20 A of A i  is advanced in the counterclockwise direction by  2   a  with respect to the head of the corresponding rod  20 A of A i−1 . 
     FIGS. 6 to 8  show that the rod allocated to stage A i−1  is not continued into the stage A i , so that the heads  21  of the rods that have been continued have advanced by a step  2   a.