Abstract:
A price totem includes a carriage for carrying the display numbers at one or more vertical spaced number locations. The carriage has upper and lower portions which can be collapsed relative to each other enabling the construction of a large carriage which can still have its numbers changed at a single number changing station, which is accessible at ground level.

Description:
TECHNICAL FIELD 
     This invention relates to indicating mechanisms for price display devices and in particular, but not exclusively to the devices known as price totems. 
     BACKGROUND OF THE INVENTION 
     An indicating mechanism is described in our British Patent No. 2289156, the disclosure of which is incorporated into this Specification. The system described in that Patent has been particularly successful in the United Kingdom, although there are some existing price totems for which retro-fitting is not an option, because there is insufficient vertical space between the lowermost price window and the ground. Further, continental garages tend to offer at least five different fuels giving rise to the need for longer carriages. 
     SUMMARY OF THE INVENTION 
     The present invention consists in an indicating mechanism for a price display device comprising, a frame defining a vertical slide way, a carriage mounted in the slide way for movement between a display position and a storage position, the carriage defining a plurality of vertically spaced number locations such that the locations can be successfully disposed adjacent a number changing station as the carriage moves between its display and storage positions, characterised in that the carriage comprises upper and lower portions each bearing at least one number location, the portions being interconnected for relative vertical sliding movement whereby the carriage can be contracted when its lower portion is in the storage position. 
     In a preferred embodiment, the lower portion slides behind the upper portion to effect contraction. Conveniently the mechanism may include a stop or abutment for engaging the lower portion to initiate contraction and most simply that abutment may be constituted by the ground on which the mechanism or the device stands. The weight of the lower portion is preferably sufficient to re-extend the carriage when the carriage is raised to the display position, but means for urging the carriage into its extended position may be provided, or, alternatively, a temporary latch may be provided for briefly restraining the lower portion as the carriage is raised to the display position, so that the lower portion is braked relative to the upper portion causing the re-extension. 
     From a further aspect the present invention consists in an indicating mechanism comprising an indicating mechanism for a price display device comprising a frame defining a vertical slide way, a carriage mounted in the slideway for movement between a display position and a number change position, the carriage defining a number location and counterbalance means for counterbalancing the weight of the carriage, including a pulley mounted on the frame above the carriage and a counterbalance weight connected to an upper part of the carriage by a flexible elongate member which passes over the pulley characterised in that the mechanism includes a further pulley located below the number change station and a further flexible member connected to the weight, extending around the further pulley to the lower part of the carriage to form, with the carriage, a closed loop with the counterbalance means, whereby the carriage can be moved vertically in the desired direction by pulling on the further flexible member. 
     The mechanism of this aspect can include any of the features of our British Patent No. 2 289 156 or the other modifications described in this Application. The arrangement enables the system described in these cases to be used, however high the display locations are. 
     Although the invention has been defined above, it is to be understood it includes any inventive combination of the features set out above or in the following description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention may be performed in various ways and a specific embodiment will now be described, by way of example, with reference to the accompanying drawings in which: 
     FIG. 1 is a front view of a price display device or totem; 
     FIG. 2 is a front view of a mechanism for use with that totem; 
     FIG. 3 is a perspective view of a carriage in its extended position; 
     FIG. 4 is a similar view of the carriage in its contracted position; 
     FIG. 5 is a front view of the carriage of FIG. 3; 
     FIG. 6 is a section along the line A—A in FIG. 5; 
     FIG. 7 is a scrap section along the line B—B; 
     FIG. 8 is a scrap section along the line C—C; 
     FIG. 9 is a scrap section along the line D—D; and 
     FIG. 10 which is a schematic view of a price display device incorporating an alternative counterbalance mechanism. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A price totem is generally indicated at  10  in FIG.  1  and includes a shell  11 , which defines price windows  12  and  13  and a number changing station  14 . It will be seen that the price windows  12  are of double width to display two digits, whilst the price windows  13  are of single width and, in the illustrated embodiment, display tenths of pence after the decimal point. 
     Contained within the shell  11  is an indicating mechanism generally indicated at  15  in FIG.  2 . The mechanism  15  comprises of frame  16  which defines a pair of slide ways  17  and  18  for respective carriages  19 ,  20 , but these can conveniently be replaced by a single full-width carriage as illustrated in the subsequent Figures. 
     In use the carriage or carriages can be pulled down progressively from the display position illustrated in the drawing so that each number location  23  becomes aligned, in turn, with the number changing station  14  when the operator has opened the station to obtain access to the mechanism  15 . The totem is provided with a recess below the number changing station  14  to receive the lower parts of the carriage. In previous designs this recess had to be sufficiently tall to accommodate all but the upper most number location, but as has been indicated this is not always possible, when there is either reduced space available or there are a greater number of number locations. 
     FIGS. 3 and 4 illustrate a full-width carriage  19   a , which has upper and lower portions  21 ,  22  each of which have respective number locations  23 . Thus in the illustrated example the upper portion has three number locations and the lower portion has two. As will be explained in more detail below, the lower portion  22  is mounted on the upper portion  21  so that it can slide up behind the upper portion  21  to contract the carriage  19   a  into the arrangement shown in FIG.  4 . It will readily be appreciated that this contraction feature enables the price mechanism of the type generally described in British Patent No. 2289156B to be used even when the height of the recess below the number changing station  14  is significantly less than the vertical height of the carriage. Thus, in the example illustrated in FIGS. 3 and 4, a carriage which provides five number locations  23  can be accommodated in a recess, which would previously have only been sufficient for use with a three number location carriage. As the principle members of the upper and lower portions  21 ,  22  are formed from extrusions, it is extremely easy to make up the carriage portions with whatever arrangement of number locations is appropriate for a particular site. 
     Turning to FIGS. 5 to  9 , the side edges at  24  of the upper portion  21  are formed from an outwardly facing generally U-shaped extrusion  24 , which has an orthogonal extension  25  on it&#39;s rear leg that defines an inwardly-facing restricted-mouth groove  26 . This receives a cooperatively formed extrusion  27  on the edge of the lower portion  22 , allowing the lower portion  22  to slide along the groove  26 . The carriage  19   a  may be mounted on the frame  15  by any of a number of means known in the art. In a preferred embodiment, the carriage is mounted on the frame by a spring loaded mechanism of the type generally described in the above mentioned British Patent. 
     As can be seen from FIGS. 7 to  9 , the number locations are provided with pairs of channels or grooves  28  for receiving sheets of material. The rearward groove typically receives a number bearing sheet, as shown at  29  in FIG. 4, where as the front groove receives a generally transparent cover, which may be coloured yellow, for example, if protection is required against sunlight. 
     As has been mentioned above the contraction of the carriage  19   a , when it enters the recess, may simply be effected by the bottom  19   b  engaging the ground or an abutment to break further downward movement of the lower portion  22 . The upper portion  21  will then continue to slide downwardly contracting the carriage. When the carriage  19   a  is raised, the weight of the lower portion  22  will generally be sufficient to cause the carriage  19   a  to re-extend, but a temporary locking latch or a weak spring element may be provided to enhance this extension, as has been set out above. 
     The mechanism, generally indicated  25 , includes an outer frame  26 , on which is mounted an inner frame  27  defining a vertical slideway  28  along which a carriage  29  can be moved from the elevated price display position indicated to a lower price change position in which it can be accessed by a person standing on the ground. The carriage  29  may have a single price or number location  30  as shown, but equally, and perhaps more usually, it will include a number of vertically spaced locations as illustrated in the above-mentioned Patent and in the preceding description. 
     Upper and lower pulleys  31 ,  32  are mounted on the top and bottom of the frame  25 . A first cord, rope or chain  33  extends from the top of the carriage  29  around the pulley  31  to the upper end  34  of a centre weight  35 , which is constrained for vertical movement by a tube  36 . A second cord, rope or chain  37  is attached to the lower end  38  of the weight  35  and extends around the lower pulley  32  to attach to the bottom of carriage  29 . Thus, the carriage  29 , the cord  33 , weight  35  and cord  37  form a closed loop. When the operator pulls downwardly on the second cord, rope or chain  37  at the point X, the carriage is lowered. If the operator pulls upwardly, the carriage is raised. The mechanism is thus suitable for use in price indicating mechanism, such as price totems, whatever the height of the totem.