Binding element for binding a stack of documents comprised of loose sheets

[0002] This invention relates to a binding element for binding a stack of documents comprised of loose sheets, having a spine piece and two side pieces, the side pieces being arranged essentially perpendicular to the spine piece.

[0003] It is an object of the present invention to provide a low-cost and easy-to-use binding element.

[0004] This object is accomplished by having the binding element made of a shape memory material or by having at least part of the binding element made of a shape memory material.

[0005] According to an advantageous further feature of the binding element of the present invention, provision is made for the two side pieces to be biased toward each other at room temperature, whereby a clamping force is exerted on the sheets of the stack of documents inserted in the space between the side pieces; to open the binding element and to insert or remove sheets of the stack of documents, the binding element is heated to a temperature that is higher than room temperature and which has been preset in the shape memory material. When the preset temperature is reached, the binding element adopts a position in which the two side pieces are spread open relative to each other.

[0006] The binding element of the present invention can be constructed in very different ways. Thus according to a first variant, the entire binding element extending either over the full length of a side edge of the stack of documents or over only a certain sub-section is made of a shape memory material. This variant is relatively expensive, so an alternative solution provides only for parts of the binding element to be made of shape memory material. Either these parts are inserted in the material of the spine piece and/or the side pieces, or they are fastened to it and/or them.

[0007] This requires the spine piece, or at least the side pieces of the binding spine, to be made of a material whose elastic force is smaller than the elastic force of the shape memory material. Once this condition is fulfilled, the form of the binding element is determined by the preset form of the shape memory material which it adopts upon reaching a predetermined temperature.

[0008] An advantageous embodiment of the binding element of the present invention provides for the part or parts made of shape memory material to be a spring or a strip-shaped part or a wire. These parts, such as springs, are fastened in accordance with a first embodiment between the two side pieces above the spine piece of the binding spine; if provision is made for the spine piece to be in the center zones of the side pieces, it is possible for the spring to be fastened between the two side pieces underneath the spine piece.

[0009] Furthermore, the part or parts made of shape memory material can have essentially the form of the binding element with its spine piece and side pieces. They are then arranged either inside the binding spine or outside the binding spine. It is also possible, however, for them to be incorporated as an integral component of the binding spine.

[0010] In another advantageous feature, a further spine piece made of random material (cardboard, plastic, metal such as spring steel, etc.) and extending over the full length of the side edge of the stack of documents to be bound is fastened to the spine piece of the binding element or to the spine pieces of the individual parts of the binding element or binding spine.

[0011] A further advantageous aspect of the binding element of the present invention provides for the part or parts made of shape memory material to be an integral component of the spine piece and/or the side pieces of the binding spine, or for the part or parts to be fastened by suitable fastening means to the spine piece and/or the side parts of the binding spine.

[0012] The present invention will be explained in more detail in the following with reference to the accompanying drawings. In the drawings,

[0013] FIG. 1ais a perspective view of a first embodiment of the binding element of the present invention;

[0014] FIG. 1bis a view of the embodiment of FIG. 1ashowing a bound stack of documents;

[0015] FIG. 2ais a view of a second embodiment of the binding element of the present invention, showing integrated parts made of shape memory material;

[0016] FIG. 2bis a view of the embodiment of FIG. 2ain open position;

[0017] FIG. 3 is a schematic representation of a third embodiment of the binding element of the present invention;

[0018] FIG. 4ais a cross sectional view of a first embodiment of the binding element of the present invention, utilizing a spring made of shape memory material;

[0019] FIG. 4bis a cross sectional view of a second embodiment of the binding element of the present invention, utilizing a spring made of shape memory material;

[0020] FIG. 5ais a cross sectional view of a first embodiment of the binding element of the present invention, utilizing a strip-shaped part made of shape memory material;

[0021] FIG. 5bis a cross sectional view of a second embodiment of the binding element of the present invention, utilizing a strip-shaped part made of shape memory material;

[0022] FIG. 5cis a cross sectional view of a third embodiment of the binding element of the present invention, utilizing a strip-shaped part made of shape memory material;

[0023] FIG. 6across sectional is a view of a first embodiment of the binding element of the present invention, utilizing a wire-shaped part made of shape memory material;

[0024] FIG. 6bis a cross sectional view of a second embodiment of the binding element of the present invention, utilizing a wire-shaped part made of shape memory material;

[0025] FIG. 6cis a cross sectional view of a third embodiment of the binding element of the present invention, utilizing a wire-shaped part made of shape memory material;

[0026] FIG. 7ais a perspective view of the embodiment of FIG. 4a;

[0027] FIG. 7bis a perspective view of the embodiment of FIG. 4b;

[0028] FIG. 8 is a perspective view of a further embodiment of the binding element of the present invention;

[0029] FIG. 9ais a perspective view of a low-cost embodiment of the binding element of the present invention;

[0030] FIG. 9bis a cross-sectional view of a further embodiment of the binding element of the present invention;

[0031] FIG. 10 is a cross-sectional view of a further variant of the binding element of the present invention;

[0032] FIG. 11 is a schematic representation of the process of inserting a part made of shape memory material in a binding element by means of an applicator; and

[0033] FIG. 12 is a schematic representation of the process of inserting a further part made of shape memory material in a binding element by means of an applicator.

[0034] FIG. 1ais a perspective view of a first embodiment of the binding element of the present invention; FIG. 1bshows the embodiment of FIG. 1awith a stack of documents inserted. The binding element 1 is made of shape memory material. The shape memory material is either metal or plastic. The binding element 1 made of shape memory material has a spine piece 4 and two side pieces 5, 6, the side pieces 5, 6 being inclined and biased toward each other in the position in which they clamp the side edges of the sheets 3 of a stack of documents 2.

[0035] Shape memory material is distinctive in that it adopts a different form at room temperature, for example, than at a higher temperature. The temperature at which this different preset form is adopted can be varied over a wide range depending on the composition of the material. The present invention utilizes this effect to the extent that the binding element 1 is able at room temperature to clamp a stack of documents between two side pieces 5, 6, particularly between the upper edges of the side pieces 5, 6. At a preset higher temperature the two side pieces are spread apart, enabling the sheets 3 of the stack of documents 2 to be inserted or removed as desired.

[0036] According to a favorable further feature, a conventional thermal binding apparatus with a receiving channel is used for heating the binding element 1.

[0037] FIG. 2aand FIG. 2bshow a second embodiment of the binding element 1 of the present invention having integrated parts 7 made of shape memory material. The spine piece 15 and the side pieces 16, 17 of the binding spine 11 are made of a material with a smaller elastic force than that of the preset shape memory material so that the form of the binding element 1 is determined at all times by the form of the shape memory material. The actual binding spine 11 can be a low-cost injection-molded or extruded part, for example. Considering that in this embodiment the consumption of relatively expensive shape memory material is low, the corresponding binding element 1 is a comparatively low-cost item.

[0038] FIG. 2ashows the embodiment of the binding element 1 of the present invention with integrated parts 7 made of shape memory material binding a stack of documents 2 along one of its side edges at room temperature. FIG. 2bshows the corresponding binding element 1 at a higher temperature in open position.

[0039] FIG. 3 is a schematic representation of a third embodiment of the binding element 1 of the present invention. The part or parts made of shape memory material are optionally a spring 8, a strip-shaped insert 9 or a wire-shaped insert 10. How these parts 8, 9, 10 can be fastened to the spine piece 15 and/or to the side pieces 16, 17 of the binding spine 11 is illustrated in the cross-sectional views shown in the following FIG. 4, FIG. 5 and FIG. 6.

[0040] FIG. 4aand FIG. 4bshow the different possibilities for installing a spring 8 above or below the spine piece 15 of the binding spine 11. A perspective view of both embodiments is shown in FIG. 7aand FIG. 7b.

[0041] FIG. 5a,FIG. 5band FIG. 5cshow three different ways of how to fasten a strip-shaped insert 9 to the binding spine 11. In the embodiments of FIG. 5aand FIG. 5b,the part made of shape memory material has as cross section essentially the same form as the binding spine 11, that is, it is comprised also of a spine piece 4 and two side pieces 5, 6. The embodiment shown in FIG. 5ccorresponds essentially to the embodiment of FIG. 4b,but with the spring 8 replaced by a strip-shaped insert 9.

[0042] The integration of a wire-shaped part 10 in the binding spine 11 is illustrated in FIG. 6a,FIG. 6band FIG. 6c.Like the embodiment with a strip-shaped part 9 illustrated in FIG. 5aand FIG. 5b,the wire 10 has essentially the form of the binding spine 1. The embodiment of FIG. 6cemulates the embodiments shown in FIG. 4band FIG. 5c.

[0043] FIG. 8 is a perspective view of a further embodiment of the binding element 1 of the present invention, in which the binding element 1 is constructed as a clip, meaning that it extends only over a limited area of the side edge of the stack of documents 2. The binding element 1 is comprised of a binding spine 11 with an integrated part 7 made of shape memory material. Like the binding spine 11, the part made of shape memory material also has a spine piece 4 and two side pieces 5, 6. The binding spine 11 and the part made of shape memory material are joined together in the area of the spine pieces 15, 4 by a fastening means 12, which in the case illustrated is a rivet joint.

[0044] FIG. 9aand FIG. 9billustrate in a perspective view a low-cost embodiment of the binding element 1 of the present invention. It is comprised of two individual elements 18 having a spine piece 4 and 4, 15, and side pieces 5, 6 and 16, 17, in which the spine pieces 4 and 4, 15 of the elements 18 are connected to a further spine piece 13 whose length is coordinated with the format of the stack of documents 2 to be bound. The two elements 18 can either be made of shape memory material or they can be constructed as shown in FIG. 9b.In this embodiment the shape memory material comprising the spine piece 4 and the side pieces 5, 6 is integrated in the binding spine 11.

[0045] A further variant of the binding element 1 of the present invention is illustrated in FIG. 10. A sub-section of the binding spine 11, which is made of plastic, for example, has an opening into which a correspondingly shaped part of shape memory material 7 can be inserted.

[0046] Applicators 14 to enable the part made of shape memory material to be inserted automatically in a binding spine 11 are illustrated schematically in FIG. 11 and FIG. 12.

[0047] According to the embodiment illustrated in FIG. 11, the binding spine 11, which is made of a material displaying a relatively small elastic force, has a recess into which a correspondingly shaped part made of shape memory material is pushed from underneath. While this part is being pushed in, the two side pieces made of shape memory material are pressed apart slightly (as indicated by the two arrows), producing in the assembled state a clamping effect between the side pieces 5, 6 made of shape memory material and the side pieces 16, 17 of the binding spine 11, which is made of a material with a relatively small elastic force.

[0048] While the applicator 14 used in FIG. 11 performs a vertical movement, the two pressing members 19 of the applicator 14 shown in FIG. 12 are movable toward and away from each other in a horizontal direction. The free legs of the two side pieces 16, 17 of the binding spine 11 are pressed together by the applicator 14 by an amount sufficient to enable a correspondingly shaped part made of shape memory material to be inserted without difficulty from above.