US2257003A - Spiral binder - Google Patents

Description

Q l Z 1941. E. N. FARKAS SPIRAL BINDER Filed Feb. 29, 1940 INVENTOR nm'( L ATTORNEY Patented Sept. 23, 1941 '1'- OFFICE srmar. amnan Emil N. Farkas, Chicago, 111., assilnor, by direct and mesne cage, 111., as trustee assignmentl,toEmi1N Paths 0111 Application February 29, 1940, Serial P1023213 This invention relates to new and useful improvements in binders for, and a method of assembling in book form of marginally perforated leaves.

More particularly, the present invention is an improvement on the spiraLbinder of plastic and highly resilient material disclosed in Patent No. 2,188,680 to. Frank F. Farkas, and its object is to preform the binder so that a book bound with it will open with leaves in registry. This I accoma plish by forming each loop of the binder so that the helix will have a compound rather than a simple pitch. The spiral is so resilient that it.

may be. readily threaded through the uniformly and equally spaced marginal perforations of a stack of leaves without deformation oftearing of the binder or leaves. The curvatures r slopes of the two halves of each loop are so altered with respect to one another that when the book-isopened the two exposed pages engaging opposed points of a loop will be in registry with one another rather than vertically displaced as would be the case if the halves of the loops were uniform.

According to the present invention the binder vis formed and set with the loops having the required contours during its manufacture and before it is threaded through the book perforations, thus avoiding the necessity of special operations on the finished book. The invention will now be fully explained with reference to the drawing in which i Fig. 1 is a plan view of one embodiment of my invention at an intermediate stage of its manufacture;

Fig. 2 is a side elevation of a book bound in accordance with the present invention;

Fig. 3 is a side elevation of a spiral binder constructed in accordance with a second embodiment of the invention;

Fig. 4 is a plan view of a third embodiment at an intermediate stage of its manufacture; and

Fig. 5 shows holes suitable for easy insertion of a spiral formed of the strip in Fig. 4.

Referring now to the drawing, I is a thin fiat strip of plastic material having parallel edges and which is so pliable that it can be readily deformed and yet sumciently resilient to retain its preformed shape when subjected to normal strains after it is formed into a helical coil.

One edge of strip 1 is mutilated by cutting out unsymmetrical wedges 2 at intervals determined by the diameter required-for the loops of the helix. The cut-out occupies about one-half the length required for each loop.

The strip is wound on a mandrel of suitable diameter into a helical coil and subjected to heat and pressure to set it. The strip 1 will thus be formed into a cylinder. When the loops of which 5 the cylinder v is made up 'are pulled out to form' open'coil, each loop. as far as the edges'viewed from the side are concerned, will have-two different curvatures: the unmutilated portions,

'i. e;, the left-hand edge'and the right-hand edge for about one-half of each loop will form substantially a semicircle, and the mutilated portionswill have a different contour, they may be horizontal. In other words the coil will have a compound instead of a uniform or simple pitch.

Thecoil thus formed is sufficiently resilient to permit its threading into the marginal perforations 3 of leaves 4. When a book thus bound is opened theper'forations in the right-hand and left-hand leaves will be in alignment since the upper ends of the perforations in the right-hand leaves rest on portions of loops having a curvature different from those portions which bear against the perforations of the left-hand leaves; As indicated in dotted linesin Fig. 2, if the 26 wedges were not cut out of. the ribbon and the.

loops of the helix were of uniform configuration,'then the right-hand leaves of the opened 5 substantially on a radius and the other half.

straight or with any other different curvature, as indicated at 5 and 6. When inserted through. the perforations of a book, the left-hand leaves of the opened book will engage portions! and the so right-hand leaves portions 8 of the helix. Since these portions are substantially in alignment, the leaves will be in registry. i

This embodiment is particularlyrecommended for narrow stock, though it is applicable to wide ribbons also.

-In the embodiment shown in Fig.4 a ribbon in of plastic material is formed with parallel but undulating edges; the undulations beingo! two different curvatures H and I2, alternating throughout the length of the strip.

When this strip 'is wound on a cylindrical .mandrel and then set, the coil thus formed will have a compound pitch Just as in- Figs. 2 and 3.

The difference is that whereas the helix of Fig. 2

will have a compound pitch along its upper or supporting edge, the helix formed of strip." will have a compound pitch along both edges;

With this type of coil the perforations in the book leaves must be large enough to permit threading of the finished coil, and may have other than symmetrical shapes, 1. e., different from the usual rectangular or circular holes. I'bur such holes are shown in Fig. 5.

What is claimed is;

1. A binder for sheets having marginal periorations, consisting of a length of plastic material preformed into a substantially compound pitch helical coil which may be screwed into said perforations, the two halves of each loop forming, at least along one edge of the length of material, a different angle with the longitudinal axis of the coil.

' both of its edges 8. difierent angle with the longitudinal axis of the coil than in the other half.

EMIL N. FARKAS.

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