GB2355105A

GB2355105A - A display with moveable flaps

Info

Publication number: GB2355105A
Application number: GB9919972A
Authority: GB
Inventors: John Richard Calvert; Michael Anthony Hobbs
Original assignee: A C EDWARDS Ltd; HAWES SIGNS Ltd
Current assignee: A C EDWARDS Ltd; HAWES SIGNS Ltd
Priority date: 1999-08-24
Filing date: 1999-08-24
Publication date: 2001-04-11
Also published as: GB9919972D0

Abstract

In a display for petroleum product prices or the like, a fastener (200) is provided for resiliently fastening a flap (223) to baseboard (221). The fastener (200) comprises a head portion (201) for retaining an axle (222) of a flap (223), a body portion, and a tail portion in the form of a leaf spring (207). The said fastener (200) is a polycarbonate or other UV-resistant material the same as that of the flap (223) in order to reduce the likelihood of in-service stud breakage. The body portion of the stud is provided with a flange (204), and said leaf spring (207) arises from said flange (204). Flaps (300) are also provided for obscuring respective segments of the display. The flaps (300) comprise a body having an edge (301), a slot (305,306) therein and an axle (307,308) extending across said slot. Said edge is provided with at least one nib (309,310,311,312).

Description

2355105 A FASTENER, A FLAP AND DISPLAY APPARATUS INCLUDING SAME

FIELD OF THE INVENTION

The present invention relates to:

(i) a fastener for resiliently fastening a first member to a second member through an opening formed in said second member; (ii) a flap for obscuring an element in a display apparatus; and (iii) a display apparatus which employs the above mentioned fastener and/or flap.

BACKGROUND TO THE INVENTION is Our patent specification GB-A-2139391 describes and claims a digital display apparatus comprising a substantially planar baseboard having one or more seven segment displays marked on a front face thereof. A flap or shield for each element of the or each display is pivotally supported for movement from a first position in which the associated element is exposed to a second position in which the associated element is covered. Selective pivoting movement of the indicated flaps enables the elements to form and display any required digit. Each flap is pivotable manually from a first position in which one face of the flap Is against the front face of the baseboard to a second position in which the other face of the flap is against the front face of the baseboard. The flaps are attached to the baseboard by mechanisms each comprising:

(L) a stud inserted into an aperture in the baseboard, the stud having a transverse aperture therethrough extending substantially parallel to the plane of the baseboard adjacent the front face thereof; (. 1.431.) an edge or axle-def ining portioxf' of the flap, being a portion of the material of the flap lying between one edge thereof and a slot formed in the material of the flap adjacent that edge; (iii) means for retaining said stud within the aperture in the baseboard; and (iv) spring means on the stud for retaining its associated flap in the first or second position.

The stud employed is a plastics member having a head region formed with a transversely extending aperture and a longitudinal slot extending from the aperture to a tail end of the stud which was provided with an outwardly extending flange. The stud is engaged in the slot of the flap and then its tail region is inserted from the front face of the baseboard through an aperture in the baseboard so that its tail appears at the rear face of the baseboard. A coil spring was placed on the tail region of the stud, after which the stud and spring are retained by a cotter that engaged the stud flange. The combination of plastics studs with metal springs and cotters is robust and gives a strong spring action holding the flaps against the baseboard in service in exposed conditions as on the forecourt of a petroleum filling station.

Our patent specification GB-A-2204630 describes and claims a fastening stud that can be used in the above mentioned seven segment displays in substitution for the existing stud, coil spring and cotter and which combines robustness and strong spring action with a one-piece construction. Such a stud comprises a head portion provided with a fastening formation and connected via an elongate body portion to a tail portion in the form of a leaf spring reverse folded along the body portion towards the head portion, the tail portion terminating in a transversely projecting flange. In use, the head portion of the stud projects through the opening in the baseboard and is connected through its fastening formation to the flap, and the flange butts against and locates behind the rear or concealed surface of the baseboard.

SM4MARY OF THE INVENTION Cormerc:Lal embodiments of the displays disclosed in GB-A-2 204 630 use studs made of polyacetal coloured with an organic colouring material, flaps made of polycarbonate also coloured with an organic colour ng material, and a baseboard which of painted acrylic sheet.

The background colour for the display may be black or it may be a house colour of the petroleum product manufacturer whose products are on sale e. g. green or red, and flaps and studs will have the same background colour. Polyacetal has been selected as the material for the studs on account of its good spring properties. We have found that after prolonged use one or more of the studs may break in service, e.g. when a display is being changed, which is an inconvenience to the filling station operator and may require a service call because stud replacement is an operation requiring dexterity. It is one of the objects of this invention to provide studs that can have increased service life and to provide displays in which stud failure is less of a problem.

Wehave also found that stud breakage can occur at the time of assembly of the display panel, either as a result of insufficiently dextrous insertion or as a result of unwanted stress or other causes of weakness introduced at the time of moulding. It is a further object of the invention to provide studs that are less i 4 likely to fail during-assembly of the display panel.

We have further noted that in existing displays, the studs may become faded at a rate that is greater than that of the flaps that they control, resulting in an observable colour difference. It is a further object of the invention to reduce the likelihood of this happening.

We believe that one of the causes of in-service stud failure is that they may deteriorate or become brittle as a result of exposure to daylight, and that this deterioration can be reduced by making both the studs and the flaps from the same UV-resistant polymeric material. We have observed that the photochemical attack on organic colour ng materials dissolved or dispersed in the polymeric material is reduced in the case of polymeric material that exhibits relatively high W- resistance, for example polycarbonate or polybutyl terephthalate. Organic colouring materials themselves impart W-resistance to polymeric materials in which they are incorporated. By making the studs of UV-res:Lstant polymeric material having one organic colouring agent dissolved or dispersed in it, not only is fading slowed but also the colour ng material continues to protect the polymeric material from UV-degradation, which offers the possibility of a substantially increased protection from photochemical degradation.

The invention provides a digital display apparatus comprising a baseboard having an opening therein, an element.. a flap for covering or exposing said element and a fastener for resiliently fastening said flap to said baseboard, wherein said fastener comprises the same material as said flap.

The fastener and the f lap will normally be of a thermoplastics resin containing a colour or pigment, and good results, as well as cost savings, can be obtained when they are both of polycarbonate resin.

The invention further provides a digital display apparatus comprising:

a baseboard having one or more segmented displays marked on a front face thereof; a flap or shield for each segment of the or each display; and at least one spring fastener or stud for each flap for attaching said flap to the baseboard and for pivotally supporting said flap for movement against a resistance provided by the resilience of said stud between a f irst position in which one face of the f lap is against the front face of the baseboard and in which the associated segment is exposed and a second position in which the other face of the flap is against the front face of the baseboard and in which the associated segment is covered, selective pivoting movement of the flaps enabling the segments to form and display a required digit, wherein the flaps and the fasteners or studs are mouldings in the same UV-resistant polymeric material.

According to a further aspect of the present invention there is provided a fastener for resiliently fastening a flap to a baseboard through an opening formed in said baseboard, said fastener comprising a head portion for retaining an axle of a flap, a body portion and a tail portion in the form of a leaf spring reverse folded along the body portion towards the head portion, wherein said fastener comprises a polycarbonate or other UV-resistant polymeric material.

6 At least the head portion should be from a polycarbonate material because it is the portion exposed to most light, and advantageously the fastener is a one- piece moulding in polycarbonate material.

The fastening formation may comprise a hook for snap engagement with an axle of the flap. The body portion may be provided with a flange and said leaf spring may extend from said f lange rather than the body as in the prior art. This arrangement enables the unfolded length of the spring to be increased and reduces the required deflection at any given point along the spring so that it becomes practical to use polycarbonate or other plastics materials whose spring characteristics are less favourable than those of polyacetal. Preferably, the leaf spring subtends an arc of at least 2700. Studs with lengthened springs as aforesaid require less dexterity to insert into the baseboard and are less prone to breakage.

Advantageously, the tail portion terminates in a transversely projecting flange for location behind the rear face of the baseboard.

The invention further provides a digital display apparatus comprising:

a baseboard having one or more segmented displays marked on a front face thereof; a flap or shield for each segment of the or each display; and at least one spring fastener for each flap for fastening said flap to the baseboard through an opening formed in said baseboard and for pivotally supporting said flap for movement against a resistance provided by the resilience of said fastener between a first position in which one face of the flap is against the front face of the baseboard and- in which the associated segment is' exposed and a second position in which the other face of the f lap is against the f ront face of the baseboard and in which the associated segment is covered, selective pivoting movement of the f laps enabling the segments to form and display a required digit, said fastener comprising a head portion for retaining an axle of a flap, a body portion and a tail portion in the form of a leaf spring reverse folded along the body portion towards the head portion, wherein said body portion is provided with a flange and said leaf spring extends from said flange.

The invention further comprises a fastener for resiliently fastening a first member to a second member through an opening formed in said second member, said fastener comprising a head portion for retaining an axle of a flap, a body portion and a tail portion in the form of a leaf spring reverse folded along the body portion towards the head portion, said body portion being provided with a flange characterised in that said leaf spring extends from said flange.

We believe that the operating forces for the flaps will be lower, the action of the flap will be smoother, and the risk of stud breakage will be reduced if the edge of the flap that brushes against the baseboard during pivoting makes local rather than line contact with the baseboard. 30 The present invention therefore also provides digital display apparatus comprising: a baseboard having one or more segmented displays marked on a front face thereof; 35 a f lap or shield for each segment of the or each 8 display; and at least one spring fastener for each flap for fastening said f lap to the baseboard through an opening formed in said baseboard and for pivotally supporting said f lap for movement against a resistance provided by the resilience of said fastener between a first position in which one face of the f lap is against the front face of the baseboard and in which the associated segment is exposed and a second position in which the other face of the f lap is against the front face of the baseboard and in which the associated segment is covered, selective pivoting movement of the flaps enabling the segments to form and display a required digit, wherein said f lap comprises a body having an edge, a recess therein and an axle arranged across said recess, and said edge being provided with at least one nib extending therefrom for contact with the front face of the baseboard.

In a further aspect, the invention provides a flap for obscuring an element in a display apparatus, said f lap comprising a body having an edge, a recess therein and an axle arranged across said recess characterised in that said edge is provided with at least one nib.

Preferably, the edge is semicircular in profile.

Advantageously, said at least one nib is located adjacent to said recess, and more preferably, the edge is provided with at least one nib either side of said recess. Said at least one nib may have a substantially square profile and preferably it has rounded corners. A.Iternatively, said at least one nib may have a substantially semicircular profile.

In general, the invention also provides a display - apparatus comprising a fastener "and/or a flap in accordance with the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference will now be made, by way of example, to the accompanying drawings, in which:

Figure 1 is a front view of a prior art digital display; Figure 2 is a view, to an enlarged scale taken along line II-II of Figure 1; Figures 3A, 3B and 3C are respectively a side elevation, end elevation and top elevation of a fastener in accordance with the present invention; Figure 4 is a view, partly in elevation and partly in section of a baseboard showing the fastener of Figures 3A to 3C in an aperture of a baseboard, the fastener being deformed in preparation for receiving a flap; Figures 5A to 5C shows the f lap attached to the fastener in a first stable flap position, an intermediate flap position and a second stable flap position respectively; Figure 6 is a front elevation of one embodiment of a flap in accordance with the present invention; Figure 7 is a front elevation of a second embodiment of a flap in accordance with the present invention; Figure 7A is an end view of part of the f lap of Figure 7; Figures 7B shows a partial end view of a third embodiment of a flap in accordance with the present invention; and Figure 7C shows a partial end view of a fourth embodiment of a flap in accordance with the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to Figure 1, there is shown a known digital display which is generally identified by reference numeral 1. The digital display 1 has two seven segment displays 3 and 4 arranged on a baseboard 2. Seven segment display 3 comprises three substantially horizontal elements 5, 6 and 7 spaced vertically, each being slightly offset horizontally. Four elements 8, 9, 10 and 11 are arranged between ends of the horizontal elements 5, 6 and 7 to form an italicised figure eight. The use of an italicised figure is, of course, a matter of preference, and a non-italicised figure eight could be used instead if preferred. Each element 5 to 11 is provided with a respective flap 12 to 18. Each flap 12 to 18 is sized so that it can obscure its respective element 5 to 11. Two fastening studs 19 to 32 are located adjacent to the ends of each f lap 12 to 18. As is known in the art these may be replaced by a single elongated centrally positioned stud which provides both atachment of the flap to the baseboard and control of the attitude of the flap with respect to its associated display segment. A further possibility is to provide more than two studs for controlling some or all of the flaps.

The fastening studs 19 to 32 are hooked over respective axles of the f laps 12 to 18, being located in respective recesses 33 to 46. Each flap 12 to 18 is moveable about the fastening studs 19 to 32 to either cover or expose its respective segment or element 5 to 11. Seven segment display 4 is similar to the seven segment display 3, although four flaps 47, 48, 49 and 50 are shown obscuring their respective elements. Flap 50 is retained by fastening studs 99 and 100 which are similar to the fastening studs 19 to 32.

Referring now to Figure 2, the fastening stud 100, which is described in GB-A-2 204 630, is in a practical is embodiment formed as a one-piece moulding in black or otherwise coloured or pigmented polyacetal, whereas the flap 50 is a one-piece moulding in black or otherwise coloured or pigmented polycarbonate. The stud 100 comprises a head portion 102 that is circular in plan and that when viewed from the side takes the form of a hook 103 which is shown hooked over an axle 104 of flap 50. An elongate stem 105 which extends from the head portion 102 has the form of a minor segment of a cylinder when viewed in profile and is internally bounded by a planar face.

The outer surface of the elongate body 105 is formed towards an end thereof remote from the head portion 102 with an out-turned flange 106 supported by a buttress 107. An in-turned flange 108 is provided below flange 106 for, amongst other things, blocking out stray light passing through the aperture 101. An arcuate leaf spring 109, approximately 12mm in length, depends from and is formed integrally with the basal region of the elongate body 105. Spring 109 curves back along the body 105 and terminates opposite inclined cam face 110 of the hook 103 in an out-turned flange 111 and an upwardly projecting 12 - locating spigot 112 having a conical si&6 wall 113 that provides a locating action against a side 114 of the aperture 101. As previously mentioned, the stud 100 requires dexterity if it Is to be inserted in position without damage or breakage, is prone to differential fading relative to the flap 50, and may fail in service as a result of photochemical deterioration.

Referring to Figures 3A to 3C, there is shown a fastening stud in accordance with the present invention generally identified by reference numeral 200.

Fastening stud 200 is moulded in its entirety from a black or otherwise organically coloured or pigmented polycarbonate material. The fastening stud 200 comprises a head portion 201 that is circular in plan and that when viewed from the side takes the form of a hook 202. An elongate body or stem 203 extends from the head portion 201, has the form of a minor segment of a cylinder when viewed in profile and is internally bounded by a planar face. The outer surface of the elongate body 203 is provided with an out-turned flange 204 formed towards an end thereof remote from the head portion 201. The elongate body 203 extends beyond the out-turned flange 204, and its lower end te=inates in an in-turned flange 205 for, amongst other things, blocking out stray light passing through the aperture into which the fastening stud 200 is inserted in use. A first end 206 of an arcuate leaf spring 207 depends from a bottom face of the flange 204 and begins at a position offset from the stem 203 oppositely to the hook 202 as shown. The spring has the form of a major segment, preferably approximately 270' of a circle and is internally bounded by a planar face. The spring, in a preferred embodiment is approximately 28mm in length when unfolded, which is 13 - longer, for the same diame- ter of baseboard aperture, than the comparable spring of the stud of Fig. 2. A tail portion 208 of the leaf spring 207 terminates opposite inclined cam face 209 of the hook 202 in an out-turned flange 210. An upwardly projecting locating spigot 211 is carried by the flange 210 and has a conical side wall 212 that, in use, provides a locating action against a side of the aperture in which the fastening stud 200 is to be inserted. A rib 213 which is semicircular when viewed from the top of the fastening stud 200, is provided on an inner face of the flange 210, which amongst other things acts as a spacer such that when in use, the distance across the fastening stud 200 from the locating spigot to the hook elongate body 201 is slightly smaller, preferably 0.2mm smaller than the diameter of the aperture in which the fastening stud 200 is located. As previously mentioned, the leaf spring 207 of the invention is longer than the leaf spring 109 of the prior art. In a preferred embodiment, the leaf spring 207 of the invention is 240% of the length of the leaf spring 109 of the prior art.

During assembly of a display, the stud is pushed through an aperture in a baseboard 221 of painted acrylic sheet material and the leaf spring 207 deformed to allow the insertion of the axle of a flap. The increased length of the leaf spring 207 may inhibit the formation of cracks due to over-stressing during assembly of the digital display.

As best seen in Figure 3C the flanges 204 and 210 which in plan have the form of closely spaced segments of a circle extend beyond the periphery of the head portion 201 and act as light baffles. The flange 205 acts as an infill, inhibiting the passage of light through the small gap between the flanges 204 and 210 such that in a b-a"cklit version of a display, detrimental stray light is inhibited from appearing at the front of the display.

During assembly of the digital display, the head portion 201 of fastening stud 200 is inserted through the aperture 220 in the baseboard 221, as shown in Figure 4.

The hook 202 is pulled or pushed through the aperture 220. During insertion, the conical side wall 212 of the locating spigot 211 passes along the edge of the baseboard until the bottom face of the baseboard 221 abuts the flange 210, thus centring the fastening stud in the aperture 220. The head portion 201 is pushed or pulled further through the aperture 220, flexing the leaf spring 207 into a sprung state. Axle 222 of flap 223 is offered up to the open side of the hook 202, along the cam face 209, pushing the head portion 201 back, and locating under hook 202. The action of spring 207 returns the hook 202 towards the baseboard 221 as shown in Fig SA.

The flap 223 is now held by the fastening stud 200, with the flap 223 in a first stable state, against the baseboard 221, as shown in Figure 5A. It should be noted that the leaf spring 207 remains under load.

When it is desired to move the flap 223 to cover or expose an element of a digital display, the flap 223 is flipped about the axle 222 located in the fastening element 200 from the first stable state to a second stable state. Figure 5B shows the flap 223 in an intermediate position between the stable states. The axle 222 is located away from the end 224 of the flap 223 such that the hook 202 is lifted, tightening the spring 207.

The flap 223 is shown in the second stable state in Figure 5C.

A flap in accordance with a second aspect of the invention shown in Figure 6, is generally identified by reference numeral 300. It may be used with existing studs or with the novel studs previously described.

The f lap 300 has a black or otherwise coloured or pigmented polycarbonate body having a first edge 301 which is substantially parallel to a second edge 302. A transverse side edge 303 and side edge 304 which has a portion cut away at approximately 45 such that the flaps obscure substantially all of their respective elements without hindering the operation of adjacent flaps. When viewed in end profile, the polycarbonate body tapers from the first edge 301 to the second edge 302. Two recesses 305 and 306 are formed in the f irst edge 301 arranged close to the ends of the flap 300. Each recess 305,306 is formed with an axle 307 and 308 which extends thereacross. The axles 307,308 are circular in cross section which, in use facilitates pivoting of the f lap about the fastening stud. The perimeter of the axle 307 and 308 at the furthest point, is substantially in line with the first edge 301. The axles 307 and 308 are preferably moulded of polycarbonate at the same time as the flap 300 is mouded.

Nibs 309, 310, 311 and 312 are provided on the first edge 301. Each nib 309, 310, 311 and 312 is preferably between 1.5mm and 2.75mm in length, and in this instance are 2.75 mm in length. They extend approximately 1.5mm.

from the first edge.

In use, the nibs 309, 310, 311 and 312 contact the baseboard as the flap 302 is turned. This is in contrast 16 - to the prior art where substan-E ally the entire length of the flap contacted the baseboard. It is believed that the use of the nibs will enhance the working life of the fastener stud and will facilitate smooth movement of the flap when the paint layer of the baseboard has become worn or locally eroded by repeated actuation of the flap, so that the contact is then between the material of the flap and the underlying material of the baseboard.

An alternative flap in accordance with the second aspect of the invention shown in Figure 7, is generally identified by reference numeral 400.

The flap 400 has a polycarbonate body having a first edge 401 which is substantially parallel to a second edge 402. A transverse side edge 403 and side edge 404 which has a portion cut away at approximately 45 such that the flaps can obscure substantially all of their respective elements without hindering the operation of adjacent flaps.

The polycarbonate body tapers in profile from the first edge 401 to the second edge 402. Two recesses 405 and 406 are formed in the first edge arranged close to the ends of the flap 400. Each recess is provided with an axle 407 and 408 arranged across openings of the recesses 405 and 406 and of circular cross section for the reason mentioned above. The perimeter of the axle 407 and 408 at the furthest point, is set back from the first edge 401.

The axles 407 and 408 are preferably moulded with the body of the flap 400. Two pairs of n bs 409, 410 and 411, 412 are provided on the first edge 401. Each nib 409, 410, 411 and 412 is preferably about 1.5mm in length, and extends approximately 1.0mm from the first edge 401. The nibs of each pair are spaced approximately 17mm apart and 17 are located on either side of each axle 407 and 408.' The first edge 401 has, in profile, a rounded end. The nibs 4091, 410, 411 and 412 extend from the body with a constant depth, to a point rearward of the axles 407 and 408, and more particularly rearward of the central axis of said axle 407 and 408. In profile, the nibs may be substantially square 413, have rounded corners 414 or be substantially semicircular 415, as shown in Figure 7A, 7B and 7C respectively.

Various modifications are envisaged to the above fastening stud, in particular, the neck portion of the elongate body may be extended in order to reduce or obviate the need for bending the hook and neck portion during assembly of the digital display. Modifications are envisaged to the above flaps, in particular, the nibs 309 to 312 and 409 to 412 may be coated in PTFE or other lubricating material to reduce or prevent wear of the painted surface of the acrylic baseboard as the flaps are pivoted from one position to another. Alternatively, the base board 221 may be provided with PTFE areas beneath the nibs 309 to 312 and 409 to 412. It can be appreciated that the nibs, in use provide a near point contact with the baseboard on to which the flap is fastened. A flap could comprise a single nib so that in use there is a single point of contact with the baseboard.

Various possibilities exist for digital displays according to the invention. In particular, a fastener in accordance with the present invention may be used with a conventional flap or a flap in accordance with the invention. A flap in accordance with the invention may de used with a conventional stud. It should be noted that the preferred stud of the invention comprises the same material as the flap. The flap may comprise a different materl - al such as polyacetal or a f ille& thermoplastic res n, the stud may also comprise that material.

Claims

Claims:

I A digital display apparatus comprising: a baseboard having one or more. segmented displays on a front face thereof; a f lap or shield for each segment of the or each display; and at least one spring stud for each f lap for attaching said flap to the baseboard and for pivotally supporting said f lap for movement against a resistance provided by the resilience of said stud between a f irst position in which one face of the flap is against the front face of the baseboard and in which the associated segment is exposed and a second position in which the other face of the flap is against the front face of the baseboard and in which the associated segment is covered,selective pivoting movement of the flaps enabling the segments to form and display a required digit, wherein the f laps and the studs are of the same UV- resistant polymeric material.
2. The display of claim 1, wherein the UV-resistant polymeric material contains an organic colouring material.
3. The display of claim I or 2, wherein the f laps and the studs are mouldings in polycarbonate.
4. The display of any preceding claim, wherein the baseboard is of an acrylic sheet.
5. The display of claim 4, wherein the front surface of the sheet has a layer of paint providing a background colour f or said display.

- 20
6. A digital display apparatus comprising:

a baseboard having one or more segmented displays marked on a front face thereof; a flap or shield for each segment of the or each display; and at least one spring fastener for each flapfor fastening said flap to the baseboard through an opening formed in said baseboard and for pivotally supporting said flap for movement against a resistance provided by the resilience of said fastener between a first position in which one face of the flap is against the front face of the baseboard and in which the associated segment is exposed and a second position in which the other face of the flap is against the front face of the baseboard and in which the associated segment Is covered,selective pivoting movement of the flaps enabling the segments to form and display a required digit, said fastener comprising a head portion for retaining an axle of the flap, a body portion and a tail portion in the form of a leaf spring reverse folded along the body portion towards the head portion, wherein said body portion is provided with a flange and said leaf spring extends from said flange.
7. The apparatus of claim 6, wherein the head portion of the fastener comprises a hook for engagement with the axle of the flap.
8. The apparatus of claim 6 or 7, wherein the tail portion of the fastener comprises a transversely projecting flange for engagement with a rear surface of the baseboard.
9. The apparatus of claim 6,7 or 8, wherein the leaf spring subtends an arc of at least 270'.

21 -
10. T he apparatus of any of claims 6-9, wherein the leaf spring has an unfolded length of about 28 mm.
11. The apparatus of any preceding claim, wherein said flap compr:Lses a body having an edge, a recess therein and an axle arranged across said recess, and wherein said edge is provided with at least one nib.
12. The apparatus of claim 11, wherein said edge in semicircular in profile.
13. The apparatus of claim 11 or 12, wherein said at least one nib is provided proximate said recess.

is
14. The apparatus of claim 11, 12 or 13, wherein said edge is provided with at least one nib either side of said recess.
15. The apparatus of any of claims 11-14, wherein said at least one nib has a substantially square profile.
16. The apparatus of claim 15, wherein said at least one nib has rounded corners.
17. The apparatus of any of claims 11-14, wherein said at least one nib has a substantially semicircular profile.
18. Digital display apparatus substantially as hereinbefore described with reference to the accompanying drawings.
19. A fastener for resiliently fastening a first member to a second member through an opening formed in said second member, said fastener comprising:

22 a head portion for retaining an axle of a f lap; a body portion; and a tail portion in the form of a leaf spring reverse folded along the body portion towards, the head portion, wherein at least a head portion of said fastener comprises a polycarbonate or other UV-res stant mater al.
20. The fastener of claim 19, which is a one-piece mould.ing in polycarbonate material.
21. A fastener for resiliently fastening a first member to a second member through an opening formed in said second member, said fastener compr s ng:

a head portion for reta n ng an axle of a flap; a body portion; and a tail portion in the form of a leaf spring reverse folded along the body portion towards the head portion, wherein said body portion is provided with a flange and said leaf spring extends from said flange.
22. The fastener of claim 21, wherein said head portion comprises a hook.
23. The fastener of claim 21 or 22, wherein said tail portion terminates in a transversely project ng flange.
24. The fastener of claim 21, 22 or 23, wherein said leaf spring subtends an arc of at least 2700.
25. The fastener of any of claims 20-24, wherein said leaf spring has an unfolded length of approximately 28mm.
26. A flap for obscuring an element in a display apparatus, said flap comprising a body having an edge, a recess therein and an axle arranged across said recess characterised in that said edge is provided with at least one nib.
27. The flap of claim 26, wherein said edge in semicircular in profile.
28. The flap of claim 26 or 27, wherein said at least one nib is provided proximate said recess.
29. The flap of claim 26, 27 or 28, wherein said edge is provided with at least one nib either side of said recess.
30. The flap of any of claims 26-29, wherein said at least one nib has a substantially square profile.
31. The f lap of claim 30, wherein said at least one nib has rounded corners.
32. The flap of any of claims 26 to 29, wherein said at least one nib has a substantially semicircular profile.
33. A digital display apparatus comprising:

a baseboard having one or more segmented displays marked on a front face thereof; a f lap or shield for each segment of the or each display; and at least one spring fastener for each flap for fastening said flap to the baseboard through an opening formed in said baseboard and for pivotally supporting said f lap for movement against a resistance provided by the resilience of said fastener between a f irst position in which one face of the flap is against the front face of the baseboard and in which the associated segment is exposed and a second position in which the other face of 24 the f lap is against the front face of the baseboard and in which the associated segment is covered, selective pivoting movement of the flaps enabling the segments to form and display a required digit, said flap comprising a body having an edge, a recess therein and an axle arranged across said recess, and said edge being provided with at least one nib extending therefrom for contact with the front face of the baseboard.
34. A digital display apparatus comprising a baseboard having an opening therein, an element, a flap for covering or exposing said element and a fastener for resiliently fastening said flap to said baseboard characterised in that said fastener comprises the s material as said flap.
35. The digital display of claim 34, wherein said material is an organically coloured or pigmented thermoplastics resin.
36. The digital display of claim 35, wherein said material is a polycarbonate.
37. A fastener for resiliently fastening a first member to a second member through an opening formed in said second member, said fastener comprising a head portion f or retaining an axle of a f lap, a body portion and a tail portion in the form of a leaf spring reverse folded along the body portion towards the head portion, said body portion being provided with a f lange characterised in that said leaf spring extends from said flange.