A HOLDING UNIT WITH A PLATE FOR HOLDING SHEET MEMBERS

Abstract: For the holding of sheet members on a holding table it is known to let the table top be provided with holes that are in connection with a suction box at the lower side of the table top. When the sheets do not cover the entire table a substantial futile air intake takes place; this can be reduced by using very small holes, but then the sheet holding becomes poorer. By the invention a strong holding is attained, especially of sheets (20) with transfer signs, from which unused, adhesive sheet portions must be drawn off, and at the same time attaining a low degree of futile air intake. This is achieved by the table top (4) being provided with transverse grooves (6) which at the opposed table edges are covered by an overlying, inwardly bent edge portion (10) of a table frame (8), and the intake then takes place through the covered, free ends (14) of the grooves. When a sheet be placed on the table with a short overlap on the said edge portion (10), the intake in the covered table area will take place along the grooves (6) below the entire sheet which gives a good holding effect with a low air consumption, and correspondingly the unutilized intake at the non-covered edge portion will be comparatively modest.

Description: A holding unit with a plate for holding sheet members, The present invention relates to a holding surface for holding laid out or spread sheet members, particu¬ larly for extra strong holding of members from which material portions sticking to a backing portion are to be peeled off. This is relevant at the production of certain types of adhesive signs, symbols etc. which are produced by cut-stamping of a length of a plastic sheet on a supporting web length and a following peeling off of the portions of the plastic sheet which do not form part of the sign or symbol picture. As a rule this ex¬ cess material cannot be peeled off in an unbroken man¬ ner, as by a progressing folding it might otherwise be pulled off in the longitudinal direction of the support¬ ing sheet; normally there are several sub areas, e.g. the centres of O's and other characters which have to be peeled off separately, and at least partly this must proceed by a direct outwardly drawing off from the back¬ ing sheet. This sheet must be held correspondingly well, which may well be done with one hand, while the peeling off is carried out with the other hand, but the productivity is naturally increased if the holding can be obtained in another manner, allowing both hands to be used in the peeling off process. Here it is close to hand to make use of a perforated holding plate, below which a suction is provided, such that the support sheet of the member to be worked on is sucked on to the plate by compara¬ tively closely spaced apertures in the latter. The larger the apertures are and the shorter the aperture spacing is, the better the holding effect becomes, but when using a large number of comparatively large aper¬ tures, the drawback occurs that by handling comparative- ly small members a considerable intake of 'false air' may take place through all the apertures that are not covered by the member; this reduces the operative vacuum and incurs a substantial waste of energy. The free aper¬ tures may of course be covered or barred in another manner, but this will be laborious and time consuming when the member size be changed relatively frequently. The purpose of the invention is to provide a device having a holding plate for the considered application by which a good suction holding effect on laid-out members is achievable without there by varying member sizes occur¬ ring any significant waste of energy or any demand for a covering of non-used suction apertures. According to the invention this is achieved by the outer surface of the holding plate being profiled with a row of parallel grooves, which at one or both ends or at one or more apertures at the bottom of each groove are in communication with a suction chamber, such that when laying out a sheet member a corresponding covering of the grooves and their connections to the suction chamber takes place. However, the sheet member cannot be sucked to a wavy engagement with the grooved surface of the plate, i.e. air can be sucked along the grooves from the concerned edge portion or portions of the member, and hereby a both static and dynamic partial vacuum in the groove areas underneath the laid out member will occur. This is obtainable even though the communication aper¬ tures to the suction chamber are comparatively small and/or are situated far apart, and especially when this is the case it will be without any significant negative consequence whether a larger or smaller free area of the plate is left at the laying out of comparatively small members on a given holding plate, as the false air in¬ take through the uncovered portion will be of very li¬ mited extent. By suction solely from an outer end portion of the grooves it is achievable that a member being placed in a covering manner at this end portion will screen from any free air intake, as all intake will take place along the grooves; already hereby a good holding suction of the members can be obtained by a relatively modest sucking capacity. The invention is described in more detail as fol¬ lows with reference to the drawing, in which:- Fig. 1 is a perspective view of a holding device according to the invention, Fig. 2 is a perspective close-up of a section thereof, Fig. 3 is a transverse section of the device, and Fig. 4 is a perspective view of a modified holding device. The device shown in Fig. 1 is a holding table 2 comprising a table top 4 provided with transverse grooves 6 in the top surface. At the opposing long sides, vertical wall portions 8 are extended horizontal¬ ly inwardly over the table top 4 as edge strips 10 over¬ lying and engaging the edge portions of the upper side of the table top. As shown in Figs. 2 and 3 the table top 4 does not expand all the way to the wall portions 8 whereby an open duct 14 will extend from a chamber 12 inside these wall portions to each groove 6 underneath the edge strip 10, this duct being constituted by the outer end of the groove. Through several stubs 16 the chamber 12 is hose connected to a suction fan 18 mounted underneath the table. When the fan 18 is operating, the hereby incurred suction in the opposed chambers 12 will cause air to be sucked through the ducts 14, i.e. from the immediate vicinity of the edge portions of the table top 4. When, as shown in Figs. 1 and 3, a sheet member 20 is placed on the table with an outer edge portion 22 of the sheet placed on top of the edge strip 10 this sheet will pre- vent this immediate air intake along the entire length of the sheet, but as indicated by an arrow a in Fig. 3 an air intake will happen all the same, viz. through the grooves 6 from the opposed free edge of the sheet. In the covered grooves 6 a partial vacuum is built up imme¬ diately, by which the sheet 20 is sucked firmly against the table top 4. The suction effect towards the table will be decreasing towards the free edge of the sheet, but the conditions can be thus adapted that also along this edge area an adequate suction effect suitable to the purpose is achieved; it is here implied that the sheet 20 is sufficiently stiff not to be sucked down into the grooves. The air intake will be of a modest extent, and even though air is also sucked through the non-covered ducts/grooves 14, 6 the required holding of the sheet 20 can be obtained by using a suction fan 18 of relatively small capacity. By way of example the grooves 6 may have a depth of 2-5 mm and a width of 5-10 mm. The holding effect of the suction would naturally be increased if the disused lengths of the edge strips 10 were covered up, respectively a barring of the air intake at the free edge of the sheet was caused, but this would be opera- tively difficult, and the system can well be designed in such a manner that it functions excellently and in an economical manner without such arrangements. By compari¬ son with an ordinary, perforated suction plate it will be seen that the air intake takes place through a con¬ stant number of openings, viz. the number of ducts 14, and this number of operative suction apertures will neither increase nor decrease whether the laid out mem¬ bers 20 are larger or smaller; by the use of a perfo¬ rated plate quite a substantial amount of apertures must be used in order to enable a good suction holding of the members, and by a laying out of small single members a considerable idle intake through the many remaining uncovered apertures will consequently take place. Nevertheless, it is also a possibility by the in¬ vention that use may be made of perforations in the plate above an underlying suction chamber, viz. for instance just a few longitudinal rows of apertures pro¬ vided at the bottom of the grooves 6 with considerable mutual distance as seen in the direction of the grooves. Even when they are very small, such apertures, however, will be able to increase the suction holding effect to the extent they are situated beneath a laid out member 20, whereby the free edge portion of larger members can be held better. In Fig. 1 it is implied that primarily it is actual to lay out sheet members 20 having a top sheet in which a sign text is made by contour cutting of letters; the text can be brought to stand out when from an underlying backing sheet the top sheet is peeled off either in the cut-out letter portions or in all the surrounding areas, and it is this peeling from the backing sheet that should be resisted by the holding of the backing sheet against the table top 4. In Fig. 4 a special embodiment is shown where the holding plate is placed vertically or preferably .as a wall member inclined slightly inwardly-upwardly. The plate 4 is translucent and is lit from within the shown element, which may be mounted on a wall or placed on a portable stand. This element is intended for making special, two-coloured or polychrome transfers of adhe¬ sive sheet. On the plate 4 is first placed a basic back¬ ing sheet 24, the upper edge portions of which are laid against an upper edge strip 10 of the element such that the remainder of the sheet member after this can be held securely by suction when it is placed against the plate 4. In advance upper sheet portions 26 have been placed or left on the sheet portion 24, these upper sheet por¬ tions 26 constituting areas in uniform colour of the required finished sign face, e.g. as shown a line con¬ tour of a flower. On another backing sheet 28 are placed or left covering sheet portions 30, which by the pre¬ vious treatment e.g. in a co-ordinate cutter are strict¬ ly adapted to a completion of the surface portions 26, e.g. differently coloured filling areas. Both the basic backing sheet 24 and the backing sheet 28 are translu¬ cent, enabling the operator to place the sheet portion 28 at such a position up against the basic sheet 24 that the filling sections 30 fit exactly into or around the sheet portions 26. The sheet sections 30 are prepared in such a manner that in being pressed against the basic backing sheet 24 they can be stuck to the latter suffi¬ ciently to allowing a following peeling off of the back¬ ing sheet 28 such that a two-coloured transfer of a dur¬ able sheet material is now left on the basic backing sheet 24. If required, one or more additional portions of sheets having variant colours may correspondingly be applied to the end product. However, the invention is not limited to the said special purpose of application, as the disclosed 'groove suction principle' may be well suited to other purposes, where a certain holding of laid out sheet or plate mem¬ bers is required, e.g. in connection with so-called processing tables or wall-mounted, lit display boards for hanging up X-ray pictures or other translucent pic¬ tures or easily exchangeable signs with or without translucent contrast portions.

Claims: C L A I M S : 1. A holding unit with a plate for holding sheet members laid out thereon, primarily for holding of double sheet members, from which top sheet portions sticking to a carrier web are to be peeled off from the carrier web for forming adhesive transfer signs of pla¬ stic sheet, said plate being connected with means for sucking the sheet members against the plate, character¬ ized in that the outer surface of the plate is profiled with a row of parallel grooves, which, at one or both ends or at one or more holes in the bottom of each groove, are connected with a suction chamber for produc¬ ing a sheet member holding suction along the sheet mem¬ ber covered partial lengths of these grooves. 2. A holding unit according to claim 1, character¬ ized in that the plate is profiled with the said grooves all the way out to at least one edge of the plate, and that along this edge there is provided a cover plate in the form of an edge strip, which overlies the holding plate, abutting the upper or outer side thereof as de¬ fined by the wave top portions between the said grooves. 3. A holding unit according to claim 1 or 2, char¬ acterized in that the holding plate is additionally provided with through-going holes in the bottom portions of the grooves, these holes communicating with a suction chamber underneath or behind the holding plate. 4. A holding unit according to claim 1, character¬ ized in that the holding plate is translucent and illu¬ minated at its rear side and that it is mounted in a substantially vertical position, preferably slightly inclined downwardly and rearwardly.

Inventors: LOLK SOEREN, LOLK, SOEREN
Applicants: NONBYE AS OLE, OLE NONBYE A/S
Application year: 1989
Main classification: G09F7
IPC codes: G09F7