Abstract:
Leaf retaining means for loosely retaining a multiplicity of leaves of material, such as sheets of paper. The leaf retaining means comprise a base portion, which is provided with at least one formation to enable it to be secured to a folder cover, and loop means, the latter has at least two points on its surface which two points are closest to an imaginary plane which does not pass through that position and which is perpendicular to the loop means, and which two points are spaced apart. The loop means are such as to enable a leaf of material, such as a sheet of paper, with a generally T-shaped aperture in it that is open at an edge of the leaf, to be releasably held by the loop means by pushing the aperture onto the loop means.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of International Application No. PCT/GB9902476, filed Jul. 29, 1999. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to leaf retaining means, for use for example in a loose-leaf folder. 
     BACKGROUND 
     One well-known construction for this kind of product comprises a plurality of openable rings secured to the spine or rear flap of a folder. The rings may be snapped open and leaves of paper having appropriate holes punched therein can be attached to the rings which can then be snapped shut to retain those leaves in the folder. 
     A problem encountered with such a construction is the cost of manufacture of the openable and closable rings. The mechanisms concerned occupy a relatively large volume and the folders cannot be packed flat. The mechanisms are made of a different material from the folders thus creating a recycling problem. Furthermore, the ring mechanism requires riveting, either through itself or through a holding plate. 
     In another previously proposed construction, a multiplicity of discs are provided, each with a flange all the way round its periphery. Leaves which are to be bound together and which may comprise a multiplicity of sheets of paper with hard sheets acting as covers and between which the sheets of paper are sandwiched, have a multiplicity of T-shaped apertures cut through the leaves along the intended spine of the folder. Each T-shaped aperture has the upright of the ‘T’ perpendicular to the intended spine and opens at that edge of each sheet. This enables one such disc to be inserted into each such aperture so that its flange engages the part of the aperture in each sheet corresponding to the horizontal part of the ‘T’. Each of the discs engages all the sheets in this way, so that the discs are spaced apart along the spine. 
     The problem with this construction is that the leaves are still free to slide relative to one another such that the binding becomes strained and even fails. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide a remedy. 
     Accordingly, a first aspect of the present invention is directed to leaf retaining means for loosely retaining a multiplicity of leaves of material, such as sheets of paper, the leaf retaining means comprising a base portion, which is provided with at least one formation to enable it to be secured directly or indirectly to a folder cover, and loop means, in which the loop means, in section at a given position around the loop means, has at least two points on its surface which two points are closest to an imaginary plane which does not pass through that position and which is perpendicular to the loop means and the base portion and which two points are spaced apart, the loop means being such as to enable a leaf of material, such as a sheet of paper, with a generally T-shaped aperture in it that is open at an edge of the leaf, to be releasably held by the loop means by pushing the aperture onto the loop means. 
     Whilst the loop means could conceivably comprise two adjacent parallel loops of wire, it is preferable that the loop means comprises a flange around a tongue of the leaf retaining means that extends from the base portion thereof. 
     The said imaginary plane may be the median bisector of the loop. The said two points may be spaced apart laterally of the general plane in which the loop lies. 
     Preferably, the flange extends on both sides of the tongue. 
     Preferably, the said formations comprise at least one groove adapted to be engaged by a corresponding internal edge of a folder. 
     In one advantageous form of the invention, the loop means are narrower at a top of the loop means to facilitate the addition or removal of leaves to the folder. 
     The first aspect of the present invention extends to a combination of at least two such retaining means and a folder being provided with at least two apertures at or adjacent to a spine of the folder at the respective ends thereof, the shape of each hole in the folder corresponding to that of the base portion of each such retaining means, the latter having been slid into the apertures in the folders. 
     This aspect of the present invention also extends to a folder having such retaining means and leaves of material, such as sheets of paper, formed with generally T-shaped apertures at the two ends of one side thereof for engaging the said retaining means, the T-shaped apertures opening at one of the edges of the leaf. 
     Each leaf may comprise a folded sheet with the T-shaped apertures being formed at the fold. As a result, if there are only two retaining means at a top and bottom of this sheet, the latter may be opened whilst still being retained in the retaining means and in the opened state there is substantially no obscurity of the central regions of the opened leaf. 
     Preferably, the folder has two parallel slots extending away from each aperture formed therein, so that the material of the folder between the slots yields to facilitate insertion of the base portion of the retaining means into the aperture of the folder and then the part of the material between the slots may be snapped against one end of the base portion of the retaining means to firmly secure the latter in the folder. At least one groove in the base portion of the retaining means can be provided to receive an edge of this folder material between the slots. 
     The folder may be made of a metal or metal alloy. In that case, at least some of the internal edges which define the apertures may be serrated to improve the securing of the retaining means in the folder. 
     According to a second aspect of the present invention, there is provided retaining means for retaining a multiplicity of leaves of material, such as sheets of paper, in a folder comprising a retainer extending upwardly from a base portion of the retaining means, the base portion being provided with a groove to engage inner edges of a folder. 
     According to a third aspect of the present invention, there is provided a folder cover, at least one leaf retainer extending from the inside of a cover, and at least one removable leaf of material, such as a sheet of paper, having a T-shaped aperture cut at an edge thereof so that what constitutes the upright of the ‘T’ is open at an edge of the leaf. 
     The present invention extends to a stamp device for stamping two such T-shaped apertures at the ends of an edge of a leaf of material, such as a sheet of paper. 
     Examples of retaining means made in accordance with the present invention will now be described with reference to the accompanying drawings, in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a side view of such retaining means; 
     FIG. 1 a  shows part of a side view of a modified form of the retaining means shown in FIG. 1; 
     FIG. 2 shows an end view of such retaining means; 
     FIG. 3 shows an underneath view of such retaining means: 
     FIG. 4 shows a view from above of such retaining means: 
     FIG. 5 shows a sectional view of retaining means shown in FIG. 1 taken along the line V—V thereof; 
     FIG. 6 shows a view from above of modified retaining means; 
     FIG. 7 shows a perspective view of a folder provided with apertures for receiving two retaining means such as the one shown in FIGS. 1 to  5 : 
     FIGS. 7 a  to  7   c  show perspective views of part of the folder and retaining means shown in FIG. 7, at successive stages during the insertion of the retaining means in the folder; 
     FIG. 8 shows a perspective view of a folder shown in FIG. 7 with such retaining means inserted therein; 
     FIG. 9 shows a large leaf of material, such as a sheet of paper, folded and provided with apertures such that, in the folded state, there appear to be two generally T-shaped apertures open to the folded edge close to the ends thereof; 
     FIG. 10 shows a folder as shown in FIG. 8 with a leaf as shown in FIG. 9 held therein; 
     FIGS. 11,  12 , and  13  show modified constructions of the retaining means shown in FIGS. 1 to  5 ; 
     FIG. 14 shows further modification of the retaining means; 
     FIG. 15 shows a plan view of a further folder in open condition with a device having apertures for receiving a plurality of retaining means each as shown in FIGS. 1 to  5 ; 
     FIG. 16 shows an end view of a tool for stamping such T-shaped holes; 
     FIG. 17 shows a plan view of a section of one part of the tool shown in FIG. 16; 
     FIG. 18 shows a cross-section through a part of the tool shown in FIG. 16; and 
     FIG. 19 shows a plan view of the tool shown in FIG. 16 with further parts thereof, not normally visible, shown in ghosted form therein. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The retaining means shown in FIGS. 1 to  5  comprises a clip  10  having a base or foot  12  around a front edge of which, and along the sides thereof extends a groove  14  and in the rear of which is formed a second groove  16 . A tongue  18  projects upwardly from the foot  12 , and around the periphery of the tongue  18  is formed a flange  20 . The flange  20  has two generally straight portions  21   a  extending from the foot  12  to respective ends of an arcuate portion  21   b  of the flange that extends around the tip of the tongue  18 . The whole clip is made integrally as a single injection moulded polypropylene component. 
     As can be seen more clearly from FIG. 5, the flange  20  comprises a rounded outer surface  22 , and two flats  24  and  26  on opposite sides of the tongue  18 . 
     As is evident from FIG. 1 a,  the groove  14  may be stepped, to provide a groove  15  which is deeper but narrower than the groove  14 , to accommodate folders of a thickness selected from more than one thickness. 
     In the modification shown in FIG. 6, the flange  22  is scalloped or otherwise thinned in the region  30  at the tip of the tongue. 
     A series of pairs of clips may be provided, each pair comprising two identical clips, and the feet of all the clips, both of the same pair and of different pairs, being identical in shape and size, but the straight portions  21   a  of different pairs being of respective different lengths, to accommodate different numbers of leaves. 
     FIG. 7 shows a folder  32  made of cardboard or polypropylene. It has two fold lines  34  and  36  between which extends the spine  38 . The latter itself may be folded as shown in ghosted form to accommodate different amounts of paper. Extending from each line  34  and  36  is a front and rear flap  40  and  42  respectively of the folder  32 . 
     In the rear flap  42  adjacent to the spine  38  and at the upper and lower ends thereof, there are provided two apertures  44 . Each of these apertures  44  has an elongate rectangular portion  46  which is only slightly wider than the foot  12  of a clip  10 , as shown in FIGS. 1 to  5 , and a further elongate portion  48  extending from The rectangular portion  46 , the portion  48  having a rounded end and generally following the contour of the inside of the groove  14  of the clip, as shown in FIGS. 1 to  5 . Two slots  50  at the upper and lower ends of the rectangular portion  46  of the aperture  44  extending inwardly therefrom towards the spine  38 . 
     Respective clips, each as shown in FIGS. 1 to  5 , are then inserted into the apertures. The front end or nose of the base  12  of each clip  10  is inserted into the rectangular portion  46 , as shown in FIGS. 7 a  and  7   b,  and the portion of the folder between the slots  50  can yield a little to facilitate this. With the edges of the folder  32  which define the portion  44  of the aperture  48  engaging the groove  14 , the nose of the base portion  12  is pushed towards the rounded end of the portion  48  of the aperture  44 , as shown in FIG. 7 b,  until the portion of the folder between the slots  50  snaps back behind the base  12  to engage the groove  16  therein, as shown in FIG. 7 c.  This secures the clip  10  firmly in the folder  32 . The same procedure is followed for each of the clips  10  shown in FIG.  8 . 
     If the clip  10  has the form as shown in FIG. 1 a,  the thickness of the material of the folder  32  would be thinner, and the aperture  44  would be slightly smaller, than as shown in FIGS. 7 to  7   c.    
     A double sheet of paper such as that labelled  60  in FIG. 9 has a fold  62  along the centre thereof. With the sheet  60  folded double, a generally key-hole shaped or T-shaped aperture  64  is punched therein with what constitutes the upright of the ‘T’ opening at the fold  62 . 
     What constitutes the horizontal part of the ‘T’ is actually rounded on its upper edge so that when the sheet of paper  60  is unfolded, the aperture  64  straddles the fold  62  and overall appears to be a dumb-bell shape. This leaf  60  can be placed on to the folder  32  so that the clips  10  project through the apertures  64  as shown in FIG.  10 . It can be seen from this Figure that there is nothing that obstructs the centre region of the leaf  60 . This is particularly valuable if the latter provides a graphical image which is not to be marred by the retaining means. At the same time, the sheet  60  can be folded back double without removing it from the retaining means since one end of the aperture  64  can follow the flange  20  as one side of the leaf  60  is folded over on to the other side. 
     The folder may be provided with a third flap  70  with further apertures  72  for receiving further clips, each as shown in FIGS. 1 to  5 . End flaps  74  may be provided at the upper and lower edges of the further flap  70 , with further apertures  76  to receive the clips that are secured at the aperture  72 . 
     In the modification of a clip shown in FIG. 11, the flange  22  extends to one side only of the tongue  18 , the latter being shifted to one side of the foot  12  to facilitate this. 
     In the modification shown in FIG. 12, there is no tongue  18 , and the flange  22  is replaced by two loops  80  and  82 . These may be made of wire instead of plastics. 
     In the modification shown in FIG. 13, the loops  80  and  82  are replaced by one single loop  84  which has a width corresponding to the spacing of the loops  80  and  82 . 
     In the modification shown in FIG. 14, there is provided a diecut polypropylene strip mounting  90  with two rivet holes  92  as provided in many conventional loose-leaf ring binders, from which extends a tongue and flange portion  20 , like the tongue and flange portion that extends from the base  12  of the clip shown in FIGS. 1 to  5 , one such tongue and flange portion being provided at each end of the mounting  90 . 
     The flange portions  20  may alternatively be provided as end parts  94  of the mounting  90 , the latter being foldable upwardly and being held in their upwardly extending positions by a snap fit. 
     Alternatively, the flange portions may be parts of clips each as shown in FIGS. 1 to  5  with or without the modification as shown in FIG. 6, and each received in apertures in the strip mounting  90  each like the apertures  44  shown in FIG.  7 . 
     In the modification shown in FIG. 15, each feature which corresponds to that shown in the previous Figures has been given the same reference numeral as used in those previous Figures. A hollow metal strip  95  is riveted onto the inside of the rear flap  42 , adjacent and parallel to the spine  38 , by two rivets  96  which extend through respective holes in the centre of respective circular troughs  97  in respective ends of a raised longitudinal central part of the strip  95 , between longitudinally extending steps  98  in the metal plate of the strip  95 . Five holes  48  are formed in the strip  95  uniformly spaced along its length, and each having generally the same shape, dimensions, and orientation when viewed from above as each hole  48  shown in the previous Figures. 
     FIGS. 16 to  19  show a tool for punching holes such as those labelled  64  in FIG.  9 . It comprises a flat bed  100  upwardly from which extend two trunnions  102  through which extends a pivot axle  104 . This axle  104  also extends through a lever  106 . 
     T-shaped die-castings  108 , each having a cross-section as shown in FIG. 1 extend downwardly from the lever  106 , with what constitutes the upright of the ‘T’ in each case extending towards the axle  104 . A strip  110  is mounted on the bed  100 , underneath the die-castings  108 . The strip  110  is provided with apertures  112  each of which generally conforms to the cross-section of each die-casting  108  and each being located so as to receive such a die-casting. 
     In addition, the bed  100  is provided with recesses  114  of the same shape and corresponding in location to the apertures  112  in the strip  110 . 
     The strip  110  is mounted on the bed  100  by way of an elongate support  116  which is provided along its side further from the axle  104  with respective recesses  118  which are in registration with the what constitutes the bottom end of the upright of the ‘T’. 
     The edge of the support  116  which is further from the axle  104  acts as an abutment surface  120  for any sheets of paper which are inserted into the tool. 
     With such a sheet thus inserted, the lever  106  is depressed so that the T-shaped holes are cut into the edge of the paper by the die-castings  108 . 
     The illustrated clip may be made of any suitable metal, metal alloy, rubber, or synthetic plastics material or other castable material. The illustrated folder may also be made of any suitable metal, metal alloy, rubber, synthetic plastics material, or rigid or semi-rigid material, not necessarily the same material as the clip. 
     The assembly of the illustrated folder and clips does not need rivets nor any special or skilled tasks to be performed. 
     The tongue  18  and flange  20  of the clip  10  shown in FIG. 1 may be replaced by a ring made integrally with the base  12 . The ring may be a complete closed “O” shape, or a closed “D” shape with a straight portion perpendicular to the base  12  at the end thereof further from the groove  16 . 
     Instead of or in addition to the double sheet of paper  60 , there may be one or more single sheets, or a stitched document such as a previously bound brochure. In each case, T-shaped apertures like those labelled  64  in the accompanying drawings may be formed in each sheet or document, or in tabs secured to each sheet or document.