VARIABLE DISPLAY BOARD

Abstract: Variable display-board or the like, comprising at least one field arranged in the front of a display board or the like and corresponding to a sign or part of a sign, said field including translucent portions and opaque portions, and a sheet adapted for displacement in parallel with said field and provided with translucent portions and opaque portions, said opaque portions of the sheet in one position of displacement being situated straight opposite the opaque portions of the field and the translucent portions of the sheet being straight opposite the translucent portions of the field while, in the other position of displacement, the opaque portions of the sheet and of the field are situated straight opposite the translucent portions of respectively the field and the sheet. The novel feature is that the field (2) as well as the sheet (3) are provided with alternatingly opaque and translucent, narrow, stripe-shaped portions (4, 6; 5, 7) localized at angles to the direction of displacement and that the translucent stripe-shaped portions are slightly narrower than the opaque portions and preferably have a width which is 80-95% of the width of the opaque portions.

Description: VARIABLE DISPLAY BOARD The present invention relates to a variable display board or the like, comprising at least one field arranged in the front of a display board or the like and corres¬ ponding to a sign or part of a sign, said field including translucent portions and opaque portions, and a sheet adapted for displacement in parallel with said field and provided with translucent portions and opaque portions, said opaque portions of the sheet in one position of displacement being situated straight opposite the opaque portions of the field, and the translucent portions of the sheet being straight opposite the translucent portions of the field while, in the other position of displacement, the opaque portions of the sheet and of the field are situated straight opposite the translucent portions of respecively the field and the sheet. It is known to make variable display boards by arranging displaceable sheet elements on an aperture, which constitutes a combination of all the signs to be shown by the display board, and to produce various signs or symbols by placing said elements in various positions. A disadvantage of prior art display boards is that the great number of movable parts therein make them expensive and complicated and, consequently, apt to come out of function. Due to the construction of prior art display boards they often can only be read straight from the front because, when they are viewed at oblique angles, the leakage of light between the sheet elements will become so noticeable that the set sign cannot be distinguished. The object of this invention is to provide a display ' board which, although it is simple in construction, gives full readability not only straight from the front, but also when viewed obliquely from the side. The essential characteristic of the display board according to the invention is that the field as well as the sheet are provided with alternatingly opaque and translucent, narrow, stripe-shaped portions localized at angles to the direction of displacement and the translucen stripe-shaped portions are slightly narrower than the opaque portions and preferably have a width which is 80-95% of the width of the opaque portions. Embodiments of the display board according to the invention will be described below with reference to the accompanying drawings, in which:- Fig. 1 shows the general construction of the front of a digital display board; Fig. 2 is a front view on an enlarged scale of a plat included in each board segment or field; Fig. 3 is a similar view of a sheet lying behind and being displaceable relative to the field; Fig. 4 shows part of a segment with the plate and the sheet of Figs. 2 and 3 in one position of displacement; • Fig. 5 shows the same part with the plate and the sheet in the other position of displacement; and Fig.. -6- is -a cross-section-on an enlarged scale of a display board field including a movable sheet and control means therefor. Fig. 1 shows only a portion of the front of a display board. In addition to this partially shown front F, the display board may include a box or the like lying behind the front and containing light sources and control means. The front plate, which is opaque, is provided with a number of fields 1 (1 a -1^) corresponding to the seven sections or fields in the display board figure. Provided in each of said fields is a variable device according to the invention. The variable devices consist of a stationary plate 2 arranged on the front plate or included therein and a shee 3 lying behind and being displaceable in parallel therewit The plate 2 and the sheet 3 has a large number of parallel, non-translucent or opaque stripes or lines 4 and respectively, positioned at angles to the intended directi of displacement. The spaces in the outer, stationary plate 2 consist o crys a -c ear or open por ons . T e spaces n t e inner, displaceable sheet 3 consist of diffusely translucent por¬ tions 7 of a colour differing from the colour of the out¬ wardly facing side of the opaque portions 4 and 5. ' The outwardly facing sides of the opaque portions in the sheet and the plate should be coloured in the same tone and agree with the tone of the remaining front plate. Because of the described construction the opaque portions 4 in said outer plate 2 will completely cover the opaque portions 5 in the rear sheet 3 in a first position of displacement shown in Fig. 4, and the inter¬ mediate, translucent and possibly coloured portions will show between said first-mentioned portions. Both when the light in the display board is on and out, the section or sections of the board figure where the inner sheet 3 is in the first position of displacement will show in contrast with the surrounding portions. In the other position of displacement shown in Fig. 5, the opaque portions 4 and 5 are situated side by side and the' coloured portions 7 of the rear sheet 3 is completely covered by the opaque portions 4 of the outer sheet 2. The section or sections of fields of the board figure where the sheets are in the last-mentioned position of displacement will coincide with the remaining display board front. The width of the translucent portions 6 and 7 might in and per se be equal to the width of the opaque portions 4 and 5 respectively, and in said other position the last- mentioned portions would jointly form an unbroken surface. Within the limits of possible accuracy of manufacture, allowances in control means and the like, it is difficult in practice to bring the sheet and the plate to take the desired exact position. The consequence of an in¬ exact orientation is that light will leak out through the passages that will arise if the sheet and the plate are not exactly aligned relative to each other. To overcome this inconvenience and permit normal manufacturing allowances, the opaque portions according to the invention are wider than the translucent portions, - ' _. - **- υ whereby there is obtained a certain overlap between the opaque portions in the "switched-off" position. It has bee found suitable to allow the width of the translucent portions to amount to about 75-90% of the width of the opaque portions. In the embodiment shown, the translucent portions are 5 mm wide and the opaque portions are 6 mm wi Changes in the display board field take place by dis¬ placement of the inner sheet 3 in parallel with the stationary outer plate 2. To prevent leakage of light in the "switched-off" position, it is desirable that the sheet 3 lies in close contact with the plate 2. The opaque portions or stripes 4 and 5 consist of thi film or colour layers applied to the interfacing surfaces of respectively the plate 2 and the sheet 3. When the plat and the sheet bear against each other, the opaque portions or stripes form an unbroken surface. A close application * however causes friction between the plate and the sheet, which means that the force required for displacement will become great and that the surfaces--will be subjected to wear. To permit displacement of the sheet relative to the plate without the surfaces trailing and wearing on each other but still maintain the required contact in the . "switched-off" position, the sheet according to the inven- tion is mounted such that the displacement substantially takes place with the surfaces spaced apart from each other From the position where the opaque portions are strai opposite each other the sheet moves slightly obliquely or in a bow towards the plate 2 so that the sheet 3 impinges the plate at an oblique angle. In the preferred embodiment shown in Fig. 6 the sheet 3 is carried by a number of links 8, which are adapted to pivot about pins 9 and 10 mounted on suitable shoulders 11 and 12, respectively, on the plate 2 and the sheet 3. In the position shown in Fig. 4, i.e. where the opaque portions 4 and 5 are situated straight opposite each other the links form right angles to the sheet and the plate. When the sheet is displaced laterally the links will pivot about their ends mounted on the plate 2 and, at the same time as the sheet is displaced laterally, it approaches the plate against which it will bear upon reaching the second position where the opaque portions cover the trans- lucent portions. Due to this construction the friction be¬ tween the plate and the sheet is entirely eliminated and there will not either be any wear of the sheet and the plate surfaces. Instead of making use of links it is of cour.se possible to use inclined glide planes, eccentrics or the like and obtain the same effect. In the example shown the displacement of the sheet 3 between the two positions is caused by an electromagnet 13 combined with a return spring 14 , said electromagnet being arranged such that, as long as current passes through it, it will keep the sheet in the position where the opaque portions show, or inversely. It is of course also possible to utilize an electromechanical device which, upon each impulse of current, causes shifting between the positions and the sheet will thus remain in position until the next impulse. An advantage of this arrangement is that the set position will remain unchanged even if the supply of current is interrupted. As the display board figure according to Fig. 1 is divided into seven individually adjustable sections or fields a-g, it is possible to produce any numeral from 0 to 9 inclusive. It is of course possible to produce other figures than numerals by means of the display board according to the invention and a numerical figure has been chosen here only as an example. The adjustment of the sheet into desired positions is effected by aprogramme unit which is adapted in a suitable manner and the design of which may vary. Display boards, in which the translucent portions of the plate 2 are crystal-clear are readable both when the ligth source lying behind is put on and put out. In display boards where this function is not considered essential, the outwardly facing side of the plate 2 may, as shown in Fig. 6, be provided with a frosted surface 15 which distributes the light penetreting through the translucent portions of the plate and sheet. An outer plate 16 with anti-reflex coated surface, in which frosted fields 17 corresponding to the display board fields 1 are provided may also be applied at some distance from the plate 2. This will give further diffusion of the light. The invention should not be considered limited to that described above and shown in the drawings but may be modified in various ways within* the scope of the appended claims.

Claims: (received by the International Bureau on 17 March 1980 (17.03.80) 1. A variable display board or the like, comprising at least one field arranged in the front of a display board or the like and corresponding to a sign or part of a sign, said field including translucent portions and opaque portions, and a sheet adapted for displacement in parallel with said field and provided with translucent portions and opaque portions, said opaque portions of the sheet in one position of displacement being situated straight opposite the opaque portions of the field, and the translucent portions of the sheet being straight opposite the trans¬ lucent portions of the field while, in the other position of displacement, the opaque portions of the sheet and of the field are situated straight opposite the translucent portions of respectively the field and the sheet, wherein the field (2) as well as the sheet (3) are provided with altern-atingly opaque and translucent, narrow, stripe- shaped portions (4, 6; 5, 7) localized at angles to the direction of displacement and the translucent stripe- shaped portions are slightly narrower than the opaque portions and preferably have a width which is 80-95% of the width of the opaque portions and the sheet (3) is mounted such that, during the displacement towards the position in which the opaque portions (5) of the sheet are straight opposite the translucent portions (6) of the field, said sheet approaches the field so that the edges of opaque portions are pressed against each other. 2. A display board as claimed in claim 1, wherein the translucent portions of the field are non-transparent while the translucent portions of the sheet suitably are transparent. 3. A display board as claimed in any of claims 1 - 2, wherein the field as well as the sheet consists of trans¬ lucent sheet material on which the opaque portions have been applied in the form of stripes, and said stripes are situated on the surface which face each other. __---___---_ OMPI / t o W WIIPPOO < Λ, STATEMENTUNDERARTICLE19 The references cited in Search Report of 1980-01-21 do not anticipate this invention, and are all marked "Category A". To make the claims more clear and to more-distinctly restric the invention over the cited references revealing the state art, we have combined former claims 1 and 2, thus restrictin the scope of the main claim.

Inventors: HAKANSSON A
Applicants: HAKANSSONS IND AB, NAESSILS LJUSSKYLTAR AB, HAKANSSON A
Application year: 1979
Main classification: G09F11
IPC codes: G09F9