Tape display device

A tape display device comprises a housing supporting a pair of parallel rollers between which a tape is adapted to be wound back and forth to display different visual information contained on the tape. The rollers are driven by a continuous belt via an electric motor. One of the rollers is a tension roller which maintains tension in the tape as it is wound back and forth between the rollers. The tension roller consists of a cylinder having end caps for providing bearing surfaces which bear on respective bushes in the housing to provide rotational mounting of the roller. A drive pinion on the outside of the housing has a stub-axle which extends through the bush and end cap and into the cylinder. A spiral tension spring is attached between the end of the stub-axle and a flange of the end cap. The spring is located within the cylinder and allows relative movement between the cylinder and pinion and maintains tension in the tape as the two rollers rotate in synchronism and the diameter of the tape on each roller varies.

This invention relates to a display device and more particularly to a 
display device having a tape or web containing display information, which 
tape or web is stretched between two parallel rollers on which the tape is 
wound, whereby winding of the tape back and forth between the two rollers 
enables different information to be displayed. The device has particular 
utility in automatic display of petroleum prices at service stations where 
frequent price changes dictate the need for a device where the price can 
be changed quickly and conveniently. 
Display devices of the general kind in question are known and one such 
device is described in European patent 0253033 in the name World Acrilux 
S.A.. Another such device is described in Australian Patent No. 596,441 in 
the name of Milwaukee Sign Company. Both these earlier patents are 
directed to the tape or web rollers and means for differentially rotating 
the rollers to compensate for the changing diameters of the rollers as the 
tape is wound from one roller to the other. The device disclosed in the 
Milwaukee Sign Company patent used clutches to engage and disengage drive 
means from the respective rollers and a differential brake to maintain 
tension in the tape. The mechanism is relatively complex and hence costly 
to produce. 
The device disclosed in the World Acrilux S.A. patent provides permanently 
engaged drive means for rotating the two rollers simultaneously and one of 
the rollers is connected to the drive means by a spiral spring; the action 
of which compensates for the variation in diameter between the respective 
rollers and maintains substantially constant tension in the tape. The 
device is a single digit device and in order to display petroleum prices 
it is necessary to arrange a number of such devices in juxtaposition. 
Since the spiral spring is arranged in a pulley housing external of a 
frame of the device, close spacing of several devices is prevented and 
this is a disadvantage of this known device. Furthermore, the stainless 
steel shafts which carry the rollers are costly and are also relatively 
heavy and both these factors contribute disadvantages to the known device. 
Accordingly it is an object of this invention to provide improvements in a 
display device of the kind in which a tape is wound back and forth between 
two spaced parallel rollers to establish a new display position of the 
tape. 
Thus, the invention provides a tension roller for a tape display device for 
maintaining tension in the tape as the tape is wound between said roller 
and a further roller spaced from the tension roller, said rollers being 
mounted within a framework with their axes mutually parallel, said tension 
roller comprising a cylinder on which the tape is wound and an axial drive 
pinion arranged externally of said cylinder at one end thereof, said drive 
pinion and said cylinder being connected by a spring to facilitate 
relative movement therebetween, characterized in that, said pinion has a 
stub-axle extending centrally within said one end of said cylinder a short 
distance and said spring is arranged within said cylinder and is connected 
between said stub-axle and by the other end to said cylinder to facilitate 
said relative movement therebetween. 
Another form of the invention provides a tape display device comprising a 
tape which carries a succession of visual information and extends between 
two spaced parallel rollers on which the tape is wound, said rollers being 
mounted in a framework and being spaced sufficient to allow an item of 
said visual information to be displayed on a portion of tape extending 
between said rollers, a drive pinion or pulley on the end of each roller 
and a drive chain or belt driven by a motor and cooperating with said 
pinions or pulleys to drive said rollers, one of said rollers being a 
tension roller having a spiral spring between the pinion or pulley and the 
roller for maintaining tension in the tape as the tape is wound between 
said rollers, characterized in that, said drive pinion or pulley of said 
tension roller has a stub-axle extending centrally within the end of said 
cylinder a short distance and said spiral spring is arranged within said 
cylinder and is connected between said stub-axle and the inside of said 
cylinder to facilitate relative movement therebetween and maintain said 
tension in the tape, and said cylinder has end portions which bear on 
respective bushes in said framework to provide bearings on which said 
cylinder rotates. 
In order that the invention may be more readily understood one particular 
embodiment will now be described with reference to the accompanying 
drawings wherein: 
FIG. 1 is a sectional front elevation of a tape display device 
incorporating the invention; 
FIG. 2 is a section along the line B--B of FIG. 1; 
FIG. 3 is a side elevation in the direction of arrow A in FIG. 1 with tape 
omitted; 
FIG. 4 is a sectional view on an enlarged scale of the tension roller of 
the device of FIGS. 1-3; and 
FIG. 5 is similar to FIG. 4 but shows the drive roller of the device 
according to FIGS. 1-3.

The tape display device is shown to comprise a housing 10 which supports 
spaced parallel milers 11 and 12 which extend between opposed sides of the 
housing 10 and are contained therein. The roller 11 is a tension roller 
and the roller 12 is a drive roller as will become apparent hereinbelow. 
The housing 10 has an open front face 13 across which a tape 14 passes in 
its travel back and forth between the rollers 11 and 12. The type 14 is 
only partly shown in FIG. 1 and passes over idler rollers 15 and 16 which 
are arranged between the tension roller 11 and the drive roller 12 in the 
path of the tape 14. The path of the tape 14 is more evident in FIG. 2. 
An electric motor 17 is mounted within the housing 10 on one side and has a 
drive gear 18 mounted on the motor shaft on the outside of the housing. A 
belt tensioning pulley 19 is mounted on the outside of the housing 
adjacent the drive gear 18 and a drive belt 20 extends over the drive gear 
18, pulley 19 and pinions 21 and 22 of the tension roller 11 and drive 
roller 12, respectively. Thus, rotation of the motor causes the belt 20 to 
drive the pinions 21 and 22 in synchronism and the motor 20 is reversible 
whereby the pinions may be driven in either direction. The tape 14 
contains visual information (not shown) for display purposes and in the 
case where the device is used to display petroleum prices, the display 
comprises the numbers 0 to 9 inclusive sequentially on the tape. Also 
appearing on the tape 14 is bar code information 23 or other coded data 24 
which can be read electronically by bar code reader 36 or electronic 
sensors 37 as the case may be to provide precise information as to the 
position of the tape whereby the motor 17 may be activated to step the 
tape from one position to another via the drive belt 20. 
Referring now to FIG. 4, there is shown on an enlarged scale a sectional 
view of the tension roller 11. The roller 11 consists of a cylinder 25 on 
which the tape is wound and which has end caps 26 inserted in the 
respective ends thereof. The end caps 26 provide a bearing surface which 
bears on respective bushes 27 located in suitable apertures in the sides 
of housing 10, respectively. The pinion 21 is a drive pinion gear having a 
stub-axle 28 which extends through a central aperture of bush 27 and past 
a flange of the end cap 26 to the inside of the cylinder 25. The stub-axle 
28 is formed integral with the drive gear of the pinion 21. 
A tension spring 29 in the form of a spiral spring in located adjacent the 
end of stub-axle 28 and extends from the stub-axle out to the end cap 26. 
The spring 29 is connected to the stub-axle via slot 30 and at the other 
end is connected to end cap 26 by insertion in a suitable locating slot 
(not shown). A spacer washer 31 is provided between the flange of the end 
cap 26 and the bush 27 and a keeper washer fits over the end of stub-axle 
28 and is retained thereon by retaining clip 33 which retains all the 
components in position. 
At the other end of the tension roller 11 the end cap 26 bears on the bush 
27 in the same manner and is rotatable thereon when the cylinder 25 is 
rotated to move the tape 14. 
As will be evident rotation of the drive pinion 21 by means of drive belt 
20 causes the stub-axle and consequently the tension spring 29 to be 
rotated which then causes the tension roller 11, that is, the cylinder 25 
to also be rotated. Of course the tension spring 29 allows differential 
rotation between the pinion 21 and the cylinder 25 whereby substantially 
constant tension is maintained on the tape 14 despite the fact that the 
tape will almost always have a different diameter on each roll depending 
upon how much tape is wound on one roll as compared to the other. 
Adjustment is necessary during assembly of the apparatus to ensure that 
the maximum extent of the tension spring 29 is not exceeded when the tape 
is wound completely off one of the rollers 11 or 12 and on to the other. 
In FIG. 5 there is shown in detail the drive roller 12 which is essentially 
the same as the tension roller 11 except that there is no tension spring 
providing a differential drive between the pinion 22 and the cylinder 25. 
A spacer 38 takes the place of the tension spring 29. Like components have 
the same reference numerals as between FIGS. 4 and 5, The essential 
difference is that the drive roller 12 of FIG. 5 has a drive plate 34 
connected between the stub-axle 28 and the end cap 26. The drive plate 24 
is connected to a flange of the end cap 26 by projections 35 on the flange 
of the end cap 26 which engage in spaced circumferential holes in the 
drive plate 34, In other words the pinion 22 is rotationally locked to the 
cylinder 25 so as to rotate therewith, The main components making up the 
rollers 11 and 12 are the same at each end of each roller and in each of 
the two rollers to reduce the number of different components. 
It should be evident to persons skilled in the art that the provision of a 
tension roller 11 and drive roller 12 which do not have a central 
stainless steel axle, means that the assembly is much lighter and less 
expensive to manufacture. Furthermore, the location of the tension spring 
mechanism inside the tension roller 11 rather than externally of the 
housing 10 provides a much more compact overall design. This means that 
the width of the pinion 21 which is outside the housing 10 may be reduced 
thereby enabling adjacent tape display devices to be arranged in much 
closer proximity. This can have considerable advantages when a number of 
such devices are arranged in juxtaposition to provide pricing information. 
In addition to the above the housing 10 is manufactured from clear plastics 
material which is moulded to the desired shape and this enables artificial 
lighting (not shown) to be located behind the device whereby information 
displayed on the tape 14 is readily visible at night. It also results in 
an extremely lightweight device. 
Clearly, the invention may take other forms to that shown in the specific 
embodiment described above. The shape and arrangement of the components 
may differ considerably and it is only important that the tension spring 
mechanism be located inside the housing 10 and that the tension roller 11 
and drive roller 12 be designed so as not to require a central axle.