WO1991002342A1

WO1991002342A1 - Rotary display unit

Info

Publication number: WO1991002342A1
Application number: PCT/GB1990/001236
Authority: WO
Inventors: David James Furnell
Original assignee: David James Furnell
Priority date: 1989-08-10
Filing date: 1990-08-08
Publication date: 1991-02-21
Also published as: GB2235328A; GB8918264D0; AU6169790A; GB9017457D0; JPH0399011A

Abstract

A rotary display unit particularly adapted to be transportable, either as a freestanding unit or as part of a vehicle. Rotating display elements (11) have a plurality of faces so that when the elements are rotated in synchronism the display changes. The faces of the elements are convex and are arranged so that on rotation a substantially constant minimum spacing is maintained between adjacent elements, thereby minimising risk of trapping of objects or parts of the body as the display elements rotate.

Description

ROTARY DISPLAY UNIT

The present invention relates to a rotary display unit and more particularly to a unit comprising a plurality of elongate elements arranged side-by-side with parallel longitudinal axes about which they rotate in synchronism. Such elements usually have three elongate faces and the unit can display three alternative images or messages.

A unit of the above type is disclosed in European Patent Application ^• 0249396A. Display devices of this type are located at poster sites, or on a smaller scale in shop windows. With these display devices the elements are triangular in cross-section with flat faces, and as the elements rotate through 120° from one display position to the next, the size of the gap between adjacent elements increases from a small size to a relatively large size and then decreases back to its original extent. Thus the danger arises of a. user's or a passer-by's finger becoming trapped in the gap, and so the displays can only be used in locations where such public access cannot occur. The present invention seeks to overcome or reduce this problem, and enable safe provision of display devices in publicly- accessible locations. Preferably the display devices of the present invention are transportable, being provided on vehicles, trailers or the like, and are operable during transit as well as when stationary.

According to a first aspect of the invention there is provided a rotary display unit comprising a plurality of elongate multi-sided elements arranged side-by-side with parallel longitudinal axes about which they are arranged to rotate in synchronism, the elements being shaped and rotated such that during rotation there is a substantially constant minimum separation of the sides.

In a preferred aspect of the present invention there is provided a rotary display unit comprising a plurality of elongate multi-sided elements arranged side-by-side with parallel longtudinal axes about which they are arranged to rotate in synchronism, the display being mounted on a vehicle and the elements being shaped and rotated such that during rotation, there is a substantially constant minimum separation of the sides.

A more general aspect the invention provides a rotary display unit comprising a plurality of elongate multi-sided elements arranged side-by-side with parallel longitudinal axes about which they are arranged to rotate in synchronism, wherein the elements are mounted on the side of a vehicle.

Preferred arrangements have three-sided convex elements. Preferably the curvature of each side is an arc of a circle centered on the opposite corner of the element. Within the context of the present specification 'vehicle' includes transportation means that do not necessarily have motive power.

The display, unit may comprise a relatively small plurality of adjacent elements, e.g. four or five, and be relatively portable. By virtue of features of the invention the displays may be mounted in various locations, in particular as the side walls or part of the side walls of a vehicle e.g. a lorry trailer or van body, without presenting a public hazard. In a particularly preferred embodiment each side wall of the vehicle may comprise one or more banks of, for example, sixteen to twenty adjacent elements. The drive for rotary display units is usually intermittent. It would be desirable, therefore, for the drive motor to be able to start up with virtually no torque, and to apply torque only after it has built up a certain speed. Thus the

5 drive mechanism may comprise a Geneva mechanism in which the driven wheel or disc is driven only during part of the rotation of the drive wheel or disc. Preferably the driven wheel comprises six segments and is rotated through 120° for each complete rotation of the drive wheel. Preferably the

10 operation of the drive wheel is under the control of a self-parking switch. An alternative drive mechanism may comprise a cam drive in which a 360° rotation of an input shaft is converted to a drive and dwell cycle.

15. Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1 shows a front view of a rotary display unit.in 20 accordance with a first embodiment of the present invention and having four elements;

Figure 2 is an enlarged cross-section of an embodiment of the invention having five elements, illustrating the 25 relative constancy of the clearance gaps between them;

Figures 3a and 3b are further enlarged views of an individual element;

30 Figure 4 shows a suitable drive arrangement for the elements;

Figure 5 is an enlarged plan view of a Geneva mechanism of the drive arrangement of Figure 4; 35 - - -

Figure 6 illustrates a cam drive mechanism, and

Figure 7 illustrates a torque limiting device.

A particularly preferred form of transportable display device is to form the side wall of a vehicle into a display unit. In this instance the display need not be small, because powered transportation is available. However, if the display is to operate during motion of the vehicle and/or when the vehicle is parked, it will be realised that it is not'possible to control the environment and passers by will be able to come into contact with the sign, perhaps unexpectedly. Therefore it is important that loose clothing, hands or other parts of the body (especially of children) cannot get caught between the elements as they rotate.

It is proposed to render the rotating elements safe by arranging their shape and/or rotation sequence so that^' a substantially constant gap is maintained between faces of the elements as they are rotated. The elements may then either be positioned very closely together so that at all times the space between adjacent elements is very small, almost touching one another, so that there is an insufficiently small opening to present a hazard. A suitable opening may be for example 1 to 5mm, preferably about 3mm. Alternatively the spacing may be arranged to present a minimum opening size that is large enough not to cause trapping of fingers or hands, and a torque limiting device can be tfsed to halt rotation in the event of a larger object becoming trapped.

In some instances small freestanding display devices may be moved from location to location, and again unless special precautions are taken, such as putting the display in an inaccessible location or covering the front of the display with a guard, the rotating elements need to be rendered safe. Again providing a substantially constant minimum spacing between the elements can be used to provide this safety requirement.

Figure 1 illustrates a display unit 10 of- the general type that may be used as a transportable display unit. For simplicity a small unit having four display elements 11 is shown, but larger units can be made in a similar manner. The unit shown could typically have a height of 70 cm. The elements 11 are mounted in a box section frame 12 which is then retained in a.casing 13. As a freestanding display the unit would be provided with a motor (not shown) that may be incorporated into the casing 13. If the unit is part of a vehicle then the motor may be mounted elsewhere in the vehicle.

Each of the elements 11 has three convex longitudinally extending faces 15, 16, 17 (Figure 2). In this arrangement the cross section of each element is a trochoid with the curve of each face being centred at the apex of the other two faces, i.e. so that face 15 is centred on a corner 18.

The elements may be made in pieces, rather than as a solid frame and be generally of a hollow tubular type construction so that the assembly is light and the individual pieces can be removed for maintenance and repair purposes. Drain holes

(not shown) are provided in the faces 15, 16, 17 to allow escape of any water, resulting for example from condensation or ingress of rain when the unit is used outside.

Figure 2 shows five trochoidal sections at various stages of rotation with the points of closest approach shaded. In this drawing the dotted outline shows a moved location with respect to the complete outline. Starting with the uppermost element (as viewed) its position, and that of the full outline (only partly drawn for clarity) of the second element are shown in the configuration when one of the faces of each element is facing frontwards to present a display for viewing. In this position the closest points are the adjacent corners of the displayed faces. This gap may be made very small. With this display all the elements are rotated in unison (not in sequence) , and^the position after a small rotation is shown by the dotted outline of the second element and the full outline of the third element. It will be observed that the closest spacing is now between the apex and the centre of the face of the adjacent element.

Further rotation to the position shown by the dotted outline of the third element and the full outline of the fourth element takes the point of closest approach to between adjacent apices at the rear of the display, and further rotation to between the centre of a face (this time on the upper element) and an apex on the adjacent lower element.

With other shapes sequential rotation may be utilised.

Figures 3a and 3b respectively show enlarged end and partially sectional front views of an individual display element 11. One end of the element is recessed at 31, and this recess itself has a central triangular recess 32 for the rotary mounting and drive of the element. The other end end of element 11 is also provided with a suitable pivot (not shown) .

Figure 4 shows a drive mechanism 40 for rotary display units in accordance with the present invention. One end of each element 11 is located and driven by means of a triangular boss 41 which fits inside recess 32. Boss 41 is slidingly mounted on a spindle 42 supported by box-section frame 12, which is conveniently bolted to the frame of a truck or other vehicle. Sliding of boss 41 from the full-line position shown in Figure 4 to the broken line position permits removal and replacement of the element 11. In use, boss 41 is held in its full-line position by a split pin 43 passing through hole 44, or by a compression spring (not shown) .

Each spindle 42 is driven via a bevel gear arrangement 45, 46 by a common shaft 47 which has numerous bearings 49 to restrict play; The shaft 47 is fixed to rotate with the driven wheel 52 of a Geneva mechanism 50. Wheel 52 has six concave sections 53 shaped to match the curvature of part 54 of the Geneva drive wheel 51. Wheel 52 also has six U-shaped slots 56 for driving engagement by pins 57 on part 58 of drive wheel 51. Drive mechanism 40, Geneva mechanism 50 and the motor are guarded by a cover of the casing 13.

In use drive wheel 51 is driven by a motor (not shown) via shaft 59, and for each operation wheel 51 is limited to a single complete operation by a self-parking switch as used for vehicle windscreen wipers. The required rotation of elements 11, and hence Geneva driven wheel 52, is 120°. To enable the motor to start up under essentially zero torque conditions, it is arranged that pins 57 engage two respective slots 56 at an intermediate or final stage of the single rotation of wheel 51. Thus during the initial stage of operation of the motor, while it is building up speed, only shaft 59 and wheel 51 need to be driven. This has the advantages that a relatively small power motor can be used and also that the rotation of the elements occurs evenly. The curved nature of the display elements is an important feature since it means that trapping fingers or catching ropes or other foreign objects between the elements is virtually'iπgpossible; it also contributes to the aesthetic appearance ^*of the unit. It also means that it is safe to use the unit in locations to which people have direct access. Combined with the compactness of the unit, this enables it to be used, safely on the side wall of a vehicle, which has important applications in the fields of advertising and information display.

A flexible coupling may be incorporated in the Geneva drive shaft 59. A different Geneva mechanism can be employed, for example one in which the drive wheel undergoes a half revolution for each third revolution of the driven wheel. Alternatively the Geneva mechanism can be omitted completely; in this case the motor is preferably located coaxially "with shaft 47 to maximise transmission efficiency. One possible drive arrangement is a 3:1 ratio bevel gear train with a Isingle 360° rotation of the motor.

An alternative intermittent drive mechanism, a cam index drive, is shown in Figure 6. With this type of mechanism there is a continuously rotating drive shaft 60 with a cammed profile. An output shaft 61 has six bearings 62 that rotate as the input shaft rotates, bearing against the substantially circular 'pause' section of the input shaft profile. When the -outwardly cammed portion 63 of the input shaft profile reaches the bearings 62 it engages between adjacent bearings and rotates the output shaft through 120°. The input shaft may be provided with more than one cammed portion, giving more frequent rotation of the output shaft. In general this type of mechanism is preferred to a Geneva mechanism because the acceleration characteristic of the output shaft rotation can be controlled by the cam profile. Various fail-safe features may be incorporated in case something does become trapped in the moving parts, or in case the mechanism jams, e.g. due to distortion caused by an accident. In particular a safety cover may be provided to retain bosses 41 in position even if a split pin 43 should fail. A torque limiting device may also be included to arrest rotation of one or more of the elements in the event of anything become trapped. A suitable torque limiting device is shown in Figure 7.

The coupling assembly shown in Figure 7 has the advantage that in addition to limiting the torque on the display elements it is also capable of tolerating some axial misalignment and therefore also serves as a flexible coupling. The assembly comprises a boss 70 and socket 71 arrangement, one side being connected to the display element shaft and the other side connected to the intermittent drive assembly (via any intervening drive train) . In the boss 70, which is of substantially cylindrival section, there are three outwardly biased ball bearings 72, a suitable bias mechanism being a spring 74 retained in a respective channel 75 into which the bearings can retract. The channels 75 are disposed above one another and angularly offset by approximately 120°. Recesses 76 are provided in the socket 71 which co-operate with respective ones of the ball bearings 72. In the event of excess torque on the display element, as would occur in the event of jamming, the force becomes sufficient to overcome the bias on the ball bearings and they are pushed back into the channels 75 and the boss rotates in the socket so that output drive is no longer transmitted to the display element. The boss rotates through a full 360° before the ball bearings have an opportunity to reengage in the recesses, which they will then do if the cause of the excess torque has been removed. Due to the 360° rotation upon reengagement, the display element will reengage in phase.

The elongate elements, as illustrated, may be mounted horizontally, or alternatively they may be mounted vertically. However, for vehicle mounting it is generally preferred to mount the slats horizontally as vertically mounted slats may present greater wind resistance and influence vehicle steering.

Claims

1. A rotary display unit comprising a plurality of elongate multi-sided elements arranged side-by-side with parallel longitudinal axes about which they are arranged to rotate in synchronism, the display being mounted on a vehicle and the elements being shaped and rotated such that during rotation there is a substantially constant minimum separation of the sides.

2. A unit according to claim 1 wherein the side faces of the elements are convex.-

3. A unit according to claim 2 wherein the elements are three sided and the convex faces comprise arcs of a circle centered on the junction of the other two faces.

4. A unit according to any preceding claim in which the display is formed integrally as at least part of a side wall of the vehicle.

5. A unit according to any preceding claim in which the rotation is driven by an intermittent drive in which a driven member is driven only during part of the rotation of the drive member.

6. A unit according to claim 5 wherein the driven member has six segments and is rotated through 120° for each complete rotation of the drive member.

7. A unit according to claims 5 or 6 wherein the drive member is under the control of a self-parking switch.

8. A rotary display unit comprising a plurality of elongate multi-sided elements arranged side-by-side with parallel longitmiinal axes about which they are arranged to rotate in synchronism, wherein the elements are mounted on the side of a vehicle,

9. A rotary display unit comprising a plurality of elongate multi-sided elements arranged side-by-side with parallel longitudinal axes about which they are arranged to rotate in synchronism, the elements having a common drive mechanism including em intermittently-operable drive member and a driven member which is driven only during a part of the operation of the drive member.

10. A rotary display unit comprising a plurality of elongate multi-sided elements arranged side-by-side with parallel longitudinal axes about which they are arranged to rotate in synchronism, the elements being shaped and rotated such that during rotation there is a substantially constant minimum separation of the sides.