Display device

An improved mode of construction is provided for a display device of the kind comprising an array of triangular-section slats rotated in synchronism in 120.degree. steps to present repeatedly to view, in sequence, three compound display surfaces, each carrying a respective poster or the like. In embodiments of the invention, each slat has a respective bearing and driving module with a respective rotary member releasably drivingly engaging the slat and with a respective cam, driving the rotary member and driven in turn by a driving shaft, passing through the cams of the bearing and driving modules of all of the slats. The bearing and driving modules are received in a stack within a hollow extrusion which forms one side member of a frame of the display device. The opposite side member of the frame receives a stack of bearing members rotatably supporting the opposite ends of the respective slats.

This invention relates to display devices of the kind comprising an array 
of slats of triangular section which are rotated in synchronism in 
120.degree. steps so as to present to view, in a repeating cycle, 
comprising three display phases, three compound display surfaces, each 
presented to view during a respective one of said display phases, each 
such compound surface being formed by the aggregate of the respective 
individual flat surfaces of the slats, whereby three different advertising 
posters, for example, can be presented to view, in succession in the same 
display space, a different one of the three posters or the like being 
presented to view, after each 120.degree. rotational step. Display devices 
of the above kind are herein referred to as being `of the kind specified`. 
Display devices of the kind specified have hitherto been relatively 
expensive to manufacture because the construction hitherto adopted has 
involved the assembly of the various parts in an inner chassis and has 
required skilled labour for such assembly. Such assembly has required 
careful fitting and adjustment of a large number of individual parts and 
thus has been expensive and labour intensive. Furthermore, the requirement 
for an inner chassis, which is subsequently fitted within a more 
aesthetically acceptable outer frame has, in the known devices, added to 
the weight of the device as well as to the cost of manufacture. 
It is an object of the present invention to provide an improved display 
device of the kind specified whereby these disadvantages can be avoided. 
According to one aspect of the invention there is provided a display device 
of the kind specified wherein each slat is supported at one end thereof by 
a respective combined bearing and driving module each comprising a 
respective housing, a respective driving member or cam rotatably mounted 
in the housing, a respective driven member rotatably mounted in the 
housing and having coupling means whereby the driving member or cam can be 
connected directly or indirectly with a driving motor, said combined 
bearing and driving modules being readily assembled into the support 
structure of the device, the arrangement being such that the slats can be 
individually fitted or removed from the assembled device by releasing the 
slats from their respective combined bearing and driving modules, without 
significantly disturbing the remainder of the assembly. 
According to another aspect of the invention there is provided a kit of 
parts comprising a peripheral framework of hollow members, a plurality of 
triangular-section slats, bearing members for the one ends of said slats, 
such bearing members being adapted to be mounted in one of said hollow 
members, and combined bearing and driving modules for the other ends of 
said slats, such modules being adapted for mounting in an opposite one of 
said hollow members. 
According to yet another aspect of the invention there is provided a 
display device of the kind specified wherein each slat is supported at one 
end thereof by a respective bearing and driving means including a 
respective rotatable driven member having a non-circular engagement 
formation for engagement with a complementary formation of an assembly 
carried by the slat at the end thereof, said assembly including a 
rotatable plug and clutch means allowing rotational adjustment of the plug 
relative to the slat between predetermined angular positions.

Referring to FIG. 1, the display device of the invention comprises, in 
common with known display devices of the kind specified, a peripheral 
rectangular frame 10 within which is mounted an array of contiguous 
parallel slats 12 which, in any of the three display phases of the device, 
in which the slats 12 are substantially stationary, together define a 
planar outwardly directed vertical display surface. As in the known 
display devices of the kind specified, each of the individual slats 12 
has, in cross section, the form of an equilateral triangle, the slats 
being supported at their ends for rotation, in the frame 10, about their 
respective longitudinal axes and being arranged to be rotated in 
120.degree. steps by a drive system described below. 
The frame 10 comprises two opposing vertical members 10a and 10b and an 
upper and a lower horizontal member 10c, 10d respectively, each of said 
members being an extrusion (for example of aluminium alloy) of 
approximately U-shaped or J-shaped cross section with the open sides of 
the sections in opposing frame members facing towards each other across 
the frame. The vertical frame member 10a houses means for supporting the 
individual slats 12 at their one ends and for driving the slats, whilst 
the vertical member 10b houses means for rotatably supporting the opposite 
ends of the slats 12. Thus, for each slat 12, there is provided, 
accommodated within the side member 10a of the frame, (FIG. 2) a 
respective bearing and driving module 14, supporting one end of the slat 
and, accommodated in the opposite side member 10b, a respective bearing 
member 16 supporting the opposite end of the slat. A single driving shaft 
18, of hexagonal cross-section, extends vertically within the side member 
10a through the modules 14 to a driving motor (not shown) mounted in the 
lower horizontal member 10d. The continuous rotation of the driving shaft 
18 produces the synchronised step-wise rotation of the slats 12, as in 
known display devices of the kind specified. 
Referring to FIG. 3, each module 14 comprises an approximately rectangular 
housing or casing 20 within which are rotatably mounted, a driven member 
22 and a driving member or cam 24. The member 22 is mounted for rotation 
about a horizontal axis corresponding with the longitudinal axis of the 
respective slat 12, and includes a body part having, in cross section, the 
form of an equilateral triangle and, extending from opposite ends of the 
body part of the driven member 22, along said horizontal axis, respective 
spigots 28 which extend through respective circular holes in the opposing 
walls of the casing 20 which holes thereby afford bearings for the member 
22. Only the spigot (referenced 28) adjacent the slat 12 is shown in FIG. 
3. At its free end, remote from the body part 22, the spigot 28 has a 
non-circular tri-axially symmetrical form for engagement in a recess, of 
complementary form, in an end cap 31 of the slat 12, whereby the slat 12 
is constrained to rotate with the body part 22. The end faces of the 
triangular body part cooperate with the inner faces of the respective 
walls of the casing 20 to locate the member 22 axially. The driving member 
or cam 24 is mounted for rotation about a vertical axis, and comprises a 
body of complex form terminating in opposite end faces which cooperate 
with the inner surfaces of the upper and lower walls of the casing 20 and 
from which end faces project respective short externally cylindrical 
spigots which extend, as a close fit, through respective circular 
apertures in the upper and lower walls of casing 20 which apertures thus 
form bearings for the cam 24. A vertical passage extends through the cam 
24 along the axis of the spigots of the latter, which are thus of hollow 
or annular form, said passage being, over part of its length, of hexagonal 
cross section complementary to the hexagonal cross-section of shaft 18, 
which extends through said passage in the assembled device, whereby the 
cam 24 is constrained to rotate with the shaft 18. The form of the body 
part of the cam 24 is, as regards its operative surface and principle of 
operation, substantially the same as that used in known display devices of 
the type specified, in which, for each triangular-section slat a 
respective cam corresponding in form with the cam 24, cooperates directly 
with the end of the respective triangular section slat, which triangular 
end part of the slat effectively forms a cooperating cam or gear so that 
during one complete rotation of the cam corresponding to cam 24, the slat 
makes one 120.degree. rotational step, followed by a relatively protracted 
pause, whereby the slat makes one complete rotation, in three steps, with 
interspersed pauses for every 3 rotations of the shaft, during continuous 
rotation of the latter. Thus the device of the preferred embodiment 
operates in exactly the same way as the known device referred to but 
utilises the separately formed driven member 22 instead of the end of the 
slat 12 itself. 
The rear wall of the casing 20 has a foot portion projecting slightly 
rearwardly therefrom which carries lateral flanges 21 on opposite sides, 
for a purpose explained below. 
Likewise, the bearing member 16 has a mounting plate at the rear which 
affords lateral flanges 17. 
The bearing members 16 are preferably in the form of integral injection 
mouldings in suitable plastics. The members 22 and 24 are likewise 
preferably integral injection moulded plastics items, whilst each casing 
20 may be formed as two complementary injection moulded shells fitted 
together along a parting line which bisects the bearing holes for the 
spigots of cam 24, around the members 22 and 24. 
The bearing member 16 which supports the opposite end of the slat 12 is a 
unitary member affording an axial spigot 30 which projects through a 
central aperture in the end cap 31 at the opposite end of the slat 12 to 
support that end of the slat 12 for rotation about its axis. The bearing 
member 16 also has an integral leaf-spring 32, an end portion of which 
extends substantially parallel with the spigot 30 and the free end of 
which, in the normal, assembled condition of the display device, closely 
adjoins the end face of the respective end cap 31 and acts as a stop to 
limit axial movement of the slat 12 away from the respective bearing 
module 14. However, the spring 32 can be depressed manually, towards the 
spigot 30 to engage in a recess in the end face of the end cap 31 which is 
of sufficient depth to allow enough axial displacement of the slat 12 to 
permit the spigot 28 of the respective module 14 to fully clear the end 
cap 31 at the end of the slat adjoining that module 14, whereafter the end 
of the slat 12 adjoining that bearing module 14 can be swung away from the 
bearing module to clear the spigot 28, allowing subsequent axial 
displacement of the slat 12 in the opposite direction to extract the 
spigot 30 of the bearing member 16 from the opposite end cap 31 whereafter 
the slat may be withdrawn from the device. 
To reduce manufacturing costs, and to facilitate assembly, the same pattern 
of end cap may be used at each end of each slat. In an simple form, such 
an end cap may be a unitary body having outer side walls which lie on the 
inside of and engage, the inner surfaces of the three side walls of the 
slat 12 when the end cap is fitted, the end cap further having a central 
circular bearing hole surrounded by a generally Y-shaped tri-axially 
symmetrical recess which serves to receive the correspondingly shaped end 
of spigot 28 when installed at the end adjoining side member 10a and to 
receive the end of leaf spring 32, when the latter is depressed, when the 
end cap is installed at the opposite end of a slat 12. 
As may be seen from FIG. 2a, the vertical members 10a, 10b formed as 
aluminium alloy extrusions having the constant cross-section shown, afford 
a front wall 40, an outer side wall 42 and a rear wall 44. A web 46 
extends forwardly from the rear wall and a flange 48 extends from the 
forward edge of the web 46, in the direction away from the outer wall 42 
to form, with the free edge portion of the rear wall 44, a channel 50 to 
receive an edge portion of a rectangular backboard 19 (FIG. 2). From the 
side of web 46 nearer the wall 42 extend a ribs 57, defining, with wall 
52, a slot 54. An opposing slot 56 is defined between wall 52 and rib 58 
extending from the outer wall 42 towards the web 46. The slots 54 and 56 
receive the flanges 21 provided on the modules 14 (in the case of member 
10a), and the flanges 17 of the members 16 (in the case of member 10b) to 
locate the modules 14 within the member 10a and the members 16 within the 
member 10b. 
In assembly of the device, the side members 10a and 10b an the lower 
horizontal member 10d are secured along respective edges of the 
appropriately dimensioned backboard 19. A motor unit (not shown) is fitted 
in the lower horizontal member, the motor being connected with a 
hexagonal-section metal driving shaft 18 extending vertically within the 
respective member 10a and having an upper, free end adjacent the upper end 
of the member 10a. A series of identical modules 14 is now fitted within 
the member 10a accommodating the shaft 18, the modules 14 being slid in 
succession over the shaft 18 so that the latter passes through the 
hexagonal-section internal passages through the cams 24 and so that the 
two flanges 21 of each module casing 20 are engaged in the respective 
opposed slots 54, 56. The first module 14 inserted is slid along the slots 
54, 56 until the respective spigot of its cam 24 engages a stop on the 
driving shaft 18 and the succeeding modules 14 are each slid down towards 
the lower horizontal member 10d until they abut the previously inserted 
module 14. Likewise the first member 16 inserted in the opposite vertical 
member 10b is slid downward towards the lower horizontal member until it 
engages an appropriate stop (not shown) and succeeding members 16 are 
likewise slid down the member 10b until each engages the previously 
inserted member 16. The top horizontal member 10c may then be secured 
holding the modules 14 and members 16 in place and the slats 12 can then 
be inserted in the unit from the front, by first engaging one end of each 
slat with a respective member 16 so that the spigot 30 of the member 16 
enters the bearing hole in the respective end cap 31, the respective leaf 
spring 32 depressed using, for example, a screw driver or the like narrow 
instrument, until the end of the spring 32 can engage in one of the 
recesses in the end cap 31, allowing the slat 12 to be displaced 
longitudinally towards the respective member 16 sufficiently to allow the 
opposite end cap 31 to clear the respective spigot 28, after which an 
axial movement of the slat in the opposite direction will engage the 
non-circular formation at the end of the spigot 28 with the complementary 
non-circular recess in the end cap 31, thereby connecting the slat 12 
non-rotatably with respect to the member 22. The last-noted axial 
displacement of the slat 12 will also allow the leaf spring 32 to spring 
out of its recess in the opposite end cap 31 whereby the free end of the 
leaf spring 32 will act as a stop to prevent sufficient axial movement of 
the slat 12 away from the respective module 14 to disengage the slat 12 
from the respective spigot 28. 
The device according to the invention has the advantage that, since the 
modules 14 and members 16 are supported directly in the same hollow 
members as afford the exterior of the frame, no internal chassis is 
required, minimising cost and weight. Furthermore, the assembly of the 
modules 14 and members 16 in the frame and the insertion, thereafter, of 
the slats 12, requires neither special tools nor equipment nor any 
particular skill since little more is involved than merely sliding the 
components into place. Furthermore, given the requisite extrusions of the 
cross section required for the horizontal and vertical members 10a, 10b 
and for the slats 12 and hexagonal section rod stock for the driving shaft 
18, constructing a display unit to any desired size involves little more 
than cutting the respective extrusions and rod to the appropriate length, 
cutting a backboard to the appropriate size and fitting the requisite 
number of prefabricated members 16 and modules 14 in place. Consequently, 
the assembly of display devices embodying the invention according to 
non-standard sizes represents no difficulty. Furthermore, assembly is so 
straightforward that it is practical to ship such display devices to 
customers in disassembled form with simple instructions for assembly, 
allowing unskilled assembly by the customers. Indeed, it would be possible 
to supply the device in the form of a kit of parts, comprising lengths of 
the respective extrusions for the slats 12, members 10a, 10b, 10c and 10d, 
modules 14, members 16, end caps 31, shaft 18 and motor, and the various 
fixtures and fasteners required, allowing the purchaser to cut the 
extrusion to the necessary lengths for any particular size of display 
device and thereafter assemble the device, or alternatively to construct 
without the need for cutting to size, a display from a kit incorporating 
extrusions, etc. already cut to size. The modules 14, of course, are 
preferably supplied already fully assembled. 
The straightforward manner of removal and replacement of the slats 12 
without requiring disassembly of the rest of the device makes it a simple 
matter to remove the slats when required for cleaning, to remove the 
respective strips of old posters and to apply the respective individual 
strips of the new poster to be displayed and to replace the slats 12 in 
the frame 10. 
In a preferred variant of the display device so far described, each slat 12 
is provided with a transparent plastics sleeve 80, (FIG. 13) of generally 
triangular section, which fits over the slat 12 with just enough clearance 
to accommodate, between each side of the slat and the adjacent side of the 
sleeve, the respective poster strip or the like bearing the appropriate 
part of the respective image to be displayed. In this embodiment, each 
sleeve 80 extends over substantially the whole length of the slat and is 
retained on the slat by end cap plugs 82, as explained below, each end cap 
plug 82 being fitted within a respective slat end cap 131, shown in FIG. 7 
which, like the end cap 31, has a stub portion of hollow rectangular 
triangular section, defined by three side walls 134, which is a close fit 
in the end of the respective slat 12, and which walls 134 terminate in an 
end wall 136, perpendicular to said walls 134, pierced by a central 
aperture 138 of the form shown. The aperture 138 receives, without radial 
play, a shank portion 140 of the respective end cap plug 82, which extends 
axially within the end cap 131 and the slat 12 and is, subject to the 
constraints referred to below, rotatable, about the slat axis, in the end 
cap 131. The outer end of the end cap plug 82 is provided by a flat head 
84 perpendicular to the axis of the end cap 131 and of the slat 12 
receiving the cap 131. Extending through the head 84 from the outer face 
thereof, and into the outer part of the shank portion 140, is a Y-shaped 
recess which exhibits triaxial symmetry and is of the same form as that 
provided in the end cap 31 described above and is thus similarly 
complementary with, and intended to receive, the end of a spigot 28 or of 
a leaf spring 32. 
Said Y-shaped recess in the end cap plug 82 likewise opens into an axial 
central bore adapted to receive the spigot 30 of a bearing member 16. 
As shown in FIGS. 9, 12 and 13, the profile of the flat head 84 of the end 
cap plug is substantially that of an equilateral triangle of the same size 
as that afforded, in cross section, by the outer periphery of the slat 12, 
but with the vertices of the triangle rounded off. 
The part of the shank portion 140 further from the flat head has, at 
120.degree. intervals therearound, longitudinally extending grooves 88 of 
part-circular cross-section and, interposed regularly between the grooves 
88, three flats or facets 90, parallel with the axis of the shank portion. 
The grooves 88 and facets 90 cooperate with longitudinally extending ribs 
92 which project from the inner sides of respective ones of the three side 
walls 134 of the end cap 131 (see FIG. 7) so as to be spaced at 
120.degree. angles from one another about the central axis of the end cap 
131 and slat 12. Thus, in each of three angular positions, 120.degree. 
degrees apart, of the end cap plug, with respect to the end cap 131, about 
the central axis of the latter, said ribs 92 engage in respective ones of 
the grooves 88 to restrain the end cap plug from rotating in the end cap. 
Such a position of the end cap plug is shown in FIG. 13. The components 
are sufficiently resilient, however, to allow the ribs 92 to spring out of 
the grooves 88 when the end cap plug is rotated forcibly, whereby the end 
cap plug can be rotated through 60.degree. to a position in which the ribs 
92 lie on the outer sides of the flats 90. Such a position of the end cap 
plug is shown in FIG. 12. The arrangement of ribs 92, grooves 88 and flats 
90 thus forms a species of clutch allowing angular adjustment of the end 
cap plug relative to the end cap. In the position of the end cap plug 
shown in FIG. 12, the flat head of the end cap plug does not project 
radially outwardly beyond the slat 12, so that a sleeve 80 can readily be 
slid onto or slid off the slat and/or image strips inserted into and 
removed from the spaces between the sides of the slat 12 and the sides of 
the sleeve 80. In the position of the end cap plug illustrated in FIG. 13, 
on the other hand, the three "apices" of the flat head 84 project 
sufficiently beyond the sides of the slat 12 and the sleeve 80 to ensure 
that the sleeve 80 and any image strips interposed between the slat 12 and 
the sleeve 80, are held reliably in place. The adjustability afforded by 
the aforesaid "clutch" also makes it simple to adjust the slats to the 
correct angular orientation when fitting the slats in place, for example 
after applying new image strips. 
The end cap plug 82 is held captive in the end cap 131 by an inner end plug 
160 which, like the end cap plug 82, is of resilient synthetic plastics 
material and comprises a generally cylindrical axial stem 162 having an 
enlarged circular head 164 at one end. 
New poster strips can readily be fitted to a slat incorporating the sleeve 
and end-plug arrangement described by rotating one end plug cap to the 
position shown in FIG. 12, sliding off the transparent plastics sleeve, 
removing the old poster strips, applying the new poster strips, sliding 
the transparent sleeve back on, over the new poster strips and finally 
rotating the end plug cap to the position shown in FIG. 13. 
To facilitate application of new poster strips further, short pieces of 
double-sided adhesive tape may be applied to the three lateral surfaces of 
each slat at one end thereof and the poster strips fitted by applying the 
appropriate ends of the poster strips to the adhesive-taped parts of the 
slat in the correct orientation and registry and subsequently sliding the 
transparent sleeve onto the slat, from the adhesive-taped end, over the 
new poster strips to hold the latter in place. 
In assembly, as illustrated in FIGS. 10 and 11, the shank portion of the 
end cap plug is inserted through the central aperture 138 of the end cap 
131 from the outer end of the latter and the stem 162 of the inner end 
plug is inserted, from the inner end of the end cap 131 into the inner end 
of an axial bore in the shank portion 140. The stem 162 has a 
circumferential external annular rib which enters into snap engagement 
with a circumferential internal annular groove around the wall of the 
last-mentioned axial bore when the stem 162 is fully inserted (see FIG. 
10). In this position, the flat head 84 is substantially in engagement 
with the outer face of the end wall 136 of end cap 131 whilst the outer 
parts of the head 164 of the inner plug cooperate with the free edges, 
remote from the end wall 136, of the side walls 134 but do not project 
radially outwardly sufficiently to interfere with the insertion of the 
thus-assembled end cap assembly into the end of the slat extrusion. 
A plurality of similar display devices may be arranged side by side and one 
above the other to form a composite display of very large size. In such a 
display, whilst the arrangement may be such that all of the units of the 
array may display, on their forwardly presented display surfaces, 
respective sections of the same picture or poster at any one time, the 
operation of the driving motors of the various units may be coordinated 
and controlled by computer for example, so that different devices in the 
array change over at different times, allowing complex and striking 
effects to be obtained, such as a "wave" or "chequered" changeover 
pattern. 
As indicated above, display devices embodying the invention may be supplied 
to customers in the form of kits of parts, which the customers may 
assemble easily to provide desired display devices. In order to facilitate 
checking of such kits to ensure they contain the required components in 
the required number, and in order to facilitate packing, and further to 
provide a package which itself illustrates to customers or prospective 
customers the general appearance of the assembled display device and which 
illustrates the correct locations of the various components, the various 
components in such kits as packed for transport or storage are preferably 
assembled in a temporary disposable frame. Such a temporary frame may, for 
example, be an integral body of inexpensive plastics material, for example 
vacuum formed sheet plastics, which may be transparent, or of plastics 
foam, and may have opposing side formation which, at least as regards 
their internal surfaces, correspond in form, at least approximately, with 
the internal surfaces of the members 10a and 10b, the bearing members 20 
being stacked in one such formation and the bearing members 16 stacked in 
the other, and with the slats 12 accomodated in a space defined between 
said formations and supported at their ends by the respective bearing 
members 16 and 20 in the same way as in the finally assembled display 
device. Alternatively the package for the kit of parts may simply comprise 
disposable temporary channels each supporting a stack of bearing members 
20 or 16, with the other components being packed in positions other than 
those they would occupy in the assembled display device.