ASSEMBLY FOR TRANSIENT MARKING OF DOCUMENTSThis invention relates to an assembly (whether in already-assembled form or still-unassembled kit form) which permits transient marking to be associated with an underlying document.
The assembly can be used for a wide variety of purposes, e.g. the transient marking of commercial and legal documents, charts and other maps (both military and civilian), working out solutions to chess problems and other pastimes such as acrostics, anagrams and so on, but it has been developed having in mind especially the needs of devotees of crossword puzzles, and will be described primarily in that context.
While one supposes that there must exist people who can correctly solve crossword-puzzle clues always at the first attempt, the general experience is that quite frequently the answers first written in will prove to be incorrect, and then have to be altered.
Any such subsequent alteration is however both unsightly and difficult to read, and thus is deplorable for both aesthetic and practical reasons. Furthermore a crossword puzzle once solved (and with the answers written in) no longer remains available as a unsolved problem for someone else who might have wished to tackle it. People have been known to address this last problem by writing the answers on tracing paper placed over the printed puzzle, but this is almost unworkable because the tracing paper cannot readily be kept in the correct position - while anyway the use of tracing paper does not solve the aesthetic and practical problems which arise from the insertion of an incorrect answer to the clue.
These are real and distressing problems for devotees of crossword puzzles, to which no satisfactory solution seems to have been found till now, even though crossword puzzles have been popular (published often in the daily press) for at least 50 years and probably much longer.
An assembly has however now been devised that makes it possible to cure this long-standing and tiresome problem, which has dogged many crossword devotees from youth upwards. This is achieved, as appears from the subsequent description of this invention, firstly by providing a transparent writing surface which can be readily placed in a position overlying a crossword puzzle and in normal use held there by frictional forces against subsequent accidental misalignment, but which is capable after use of being detached for cleaning and re-use. Secondly, however the transparent writing surface must be of such a nature that in conjunction with suitably selected writing and obliterating instruments it can be both marked and obliterated at will until the puzzle-solver has finally achieved the correct solution to the crossword puzzle.The resultant assembly is both aesthetically-pleasing in itself and capable of use to solve an underlying crossword puzzle in a neat fashion, no matter what errors may have crept in along the way but which afterwards can be cleaned to eliminate the solution, and make the whole puzzle available for another to solve all over again.
According to this invention there is provided an assembly (in either already-assembled or kit form) which comprises: - (A) a generally-planar, transparent sheet of resiliently-flexible material, and having a surface capable of receiving and being wetted by a water-based ink; - (B) a generally-planar backing member at least partially underlying and generally adjacent to said transparent sheet, said backing member being either formed integrally with or attached to said transparent sheet along one edge thereof so that a document or bundle of documents can be embraced between the backing member and the transparent sheet, viewed through the latter and normally held in frictional contact therewith;; - (C) a writing instrument containing and capable of delivering an essentially aqueous water-based ink to make a transient marking upon the surface of the transparent sheet, said ink comprising pigment particles finely dispersed in water, with or without other appropriate adjuvants such as polar solvents and/or co-solvents as well as optionally surfactants to adjust the surface tension of the ink relative to the transparent sheet; and - (D) an obliterating instrument capable of effectively annulling any marking made by said waterbased ink upon the surface of said transparent sheet.
The sheet must of course be substantially transparent so that the user can read the underlying document therethrough. It is not necessary for the backing member to be transparent, but for ease and cheapness of manufacture the overlying planar sheet and the backing member are integrally formed along one common edge thereof, creating an unitary construction.
Consequently both the sheet and backing member will best be formed of the same, fairly rigid but resiliently-flexible transparent sheet material, in order that the backing member may be slightly flexed away from the transparent sheet thus to receive a possibly-folded newspaper, map or other document in the space therebetween - and thereafter, when the backing member is allowed to spring back, it will hold the document firmly in frictional engagement with the back of the transparent sheet, so that no problems of relative movement and thus misalignment between the underlying crossword puzzle and the overlying "solution" are likely to occur in use.
For all these reasons and others, it is preferred that the resiliently-flexible, transparent sheet member should be formed of a synthetic resin material with these qualities, e.g. polyvinyl chloride (PVC) which is commercially available from many sources, including the manufacturers known as PPE. Within the limits of experience so far, it appears that very satisfactory results can be obtained using either PVC sheeting of 1 mm thickness or less, e.g. 700 microns thickness.
As already indicated above, the writing instrument must contain a water-based ink containing finelydispersed pigment particles, and very preferably should be free from any dissolved dye or similar colourant.
It can thus advantageously be of the kind generally known as "washable ink", in the sense that even after drying it can be readily removed from the surface of the sheet (or indeed from the user's clothes) simply by washing with water or even by wiping with a damp cloth or tissue, leaving no obvious residue thereafter. One such washable ink which has proved entirely satisfactory for present purposes is that marketed in a range of writing instruments which are commerciallyavailable under the name "Pelikan Super-Pirat" fromPelikan U.K. Limited of Peterborough, England.
The obliterating instrument can be as straightforward as a rubbery eraser, which if used even before and also after the ink has dried upon the surface of the transparent sheet will (if suitably selected for its known qualities) serve adequately to "rub off" the ink and thus annul any mistaken entry without perceptible damage to the transparency of the sheet.
When using such a conventional, rubbery eraser it may possibly be better to await complete drying of the previously-applied ink before using the eraser, as otherwise there is a certain tendency to smear the ink and in that event initially impair the appearance of the marking, but it is not essential to wait until the ink is dry since experience has shown, rather surprisingly, that continued use of the eraser will prove fully effective. This possibly can be explained on the basis that smearing of the ink helps to dry it, but it is not known whether that is so or not. Be that as it may, it is currently much preferred that the obliterating instrument should be a tampon soaked with an aqueous oxidizing/bleaching agent capable of substantially decolouring the pigment particles in the water-based ink.
The bleaching agent must be one capable of dissolving in and performing its bleaching function in an aqueous base (with or without organic solvents and co-solvents) so that it can effectively decolour the pigment particles in the washable ink aforesaid, either before or even after said ink has dried upon the surface. The bleaching agent employed must be sufficiently powerful to decolour said pigment particles practically completely within a short period such as a second or two, and for that purpose it appears at present that suitable bleaching agents which are readily available and economic to employ include chlorate and/or hypochlorite salts, e.g. sodium chlorate and sodium hypochlorite.One such bleaching agent which in experience so far has proved very satisfactory is that employed in the so-called "killer end" of the combined writing/obliterating instrument sold under the name "Fantastic" by Jolly BrevillierUrban Schreibwarenfabrik Gesellschaft m.b.h., ofNeudorf, Austria.
The assemblage of this invention may have a number of other preferred features. The basic elements of the assemblage may be brought together extemporaneously, though it is almost essential that the transparent sheet and the associated backing member will be preassembled-together during manufacture - but in any event all the four basic elements will need to be sold in kit form for the convenience of the intended user, and they may therefore with advantage (both for purposes for sale and also in subsequent use) be associated with one another, at least by means of external packaging but desirably also alternatively or additionally by provision of means whereby the writing and/or obliterating instrument(s) may be detachably secured to the transparent sheet and backing member essembly.
At this point it is convenient to observe that for ease of use it is very advantageous if the respective marking and obliterating instruments are both supplied in a single composite marking/obliterating instrument, one at each end of it. Such a composite instrument can best be associated with the preassembled transparent sheet and backing member by providing a gripper member at and at least partly along one of the edges of the transparent sheet, within which such a composite instrument can be accomodated and retained.Such a gripper member may desirably be provided in the form of a laterally-extending flange portion of the transparent sheet situated along one of the side edges (as contrasted with the top and bottom edges) of the transparent sheet and curled upwardly out of the plane of that sheet so that in cross-section it extends round just over a semi-circle, constituting a kind of flexible clip within which a marking or obliterating or preferably a composite marking-and-obliterating instrument can be inserted and retained against accidental dislodgement.
Moreover, while the kind of attachment means mentioned above are probably most suitable when the assemblage is not in actual use but merely stored for future use, if one imagines the user employing the assemblage for instance on his or her knee during a train journey, it will be appreciated that some means of temporarily retaining the marking and/or obliterating instrument(s) so that they are not lost during interruptions is/are very desirable. Such temporary retaining means can include one (or even if possible more than one) of the following.
The transparent sheet, as well as probably the underlying backing member will usually and conveniently be of generally-rectangular outline, and in that case small indents may readily be incorporated opposite one another in opposed edges of at least the transparent sheet (and if appropriate also of the underlying backing member), these opposed indents being able to receive and locate an elastic band embracing the sheet, under which the writing and/or obliterating instrument(s) can be held temporarily in position.
Alternatively or in addition, it may be advantageous if the transparent sheet is provided with a channel-section member, arranged along at or near the edge opposite that along which the backing member is integrally formed or attached, but depressed out of the plane of the transparent sheet, so as thereby to provide a small gully, of such dimensions as to accommodate the writing and/or obliterating instrument(s) at or adjacent the bottom edge of the writing surface of the transparent sheet.
The sheet serving as the writing surface of the griper member must of course be generally transparent so that the user can read the underlying documents, but this does not preclude the provision of certain appropriate markings thereon, e.g. a grid-pattern marking which serves to locate the underlying document correctly relative to the writing surface.
In order that the invention may be well understood one simple and therefore currently preferred embodiment of it will now be described in more detail, though by way of illustration only, with reference to the accompanying drawings in which:Figure 1 is a plan view of the generally-planar, transparent sheet constituting the writing surface in the assembly;Figure 2 is a side-elevational view of the combined transparent sheet of Figure 1 and the backing member integrated therewith;Figures 3 is a perspective view of the embodiment of Figures 1 and 2, lying in a near-horizontal position as it might be in use upon a puzzle-solver's knee or upon a table;Figures 4, 5 and 6 are views of the assembly similar to those shown in Figures 1-3, but with retaining means for the writing/obliterating instrument in situ thereon; andFigures 7, 8 and 9 are views similar to those ofFigures 1-3 (and indeed Figures 4-6) but modified by incorporation of gripper members able to secure a marking/obliterating instrument securely thereon during storage or transportation.
Referring to Figures 1-3, it will be seen that the generally-planar, transparent PVC sheet 1 provides the writing surface of the assembly, which overlies a backing member 2, the transparent sheet 1 and backing member 2 being formed of the same 700 micron thickness transparent PVC sheeting, thermoformed into a U-section bend at 3, so that the transparent sheet 1 and backing member 2 lie parallel to each other, separated by a space just sufficient to accommodate a newspaper or other document (not shown) therebetween and under spring flexure hold that document reasonably firmly by frictional engagement therein.
Both the transparent sheet 1 and the underlying backing member 2 are provided with opposed indents 4a, 4b and 5a, 5b which serve a purpose better illustrated and described below.
Referring now to Figures 4-6 (wherein the same reference numerals are employed to represent the same components as in Figures 1-3) it will be seen that elastic bands 6 and 7 embrace both the transparent sheet and the backing member, being located in respectively the indents 4a, 4b and 5a, 5b. As shown in Figure 6, these elastic bands can be employed as a temporary retainer for a composite marking/obliterating instrument generally indicated 8, which is double-ended and has a marking end (schematically indicated 9) and a "killer" end schematically indicated 10.
And referring finally to Figures 7-9 (where again the same parts are indicated by the same reference numerals as in previous Figures) it will be seen that gripper members 11 and 12 are provided along one edge of the transparent sheet 1, in the form of small circlips thermoformed out of the transparent sheet 1 and (as can best be seen in Figure 9) of generally semi-circular construction but so formed as to slightly-encircle a double-ended markingtobliterating instrument (not here shown) and retain it firmly in position during storage or transportation.