Reversible Locking Paper Clip

Abstract

A locking paper clip comprising a single continuous length of wire which is bent to form two overlapped sections extending from a common base. Each section is of U-shape with substantially parallel legs, one of the legs of each section extending from the common base. The other of the legs of each section is a free leg with a free end and it extends midway between the legs of the other section and parallel thereto. A first of the sections is longer than the second such that the free leg of the first section is longer than the free leg of the second section. Each of the free ends of the free legs is bent to form a portion extending at an angle in two directions such that in a first position of the clip, sheets of material can be inserted between the sections whereafter the clip can be reversed by pivoting around the free legs as fulcrums to cause the bent ends to grip the sheets and prevent withdrawal thereof from the clip.

Description

BACKGROUND

a. Field of the Invention

The invention relates to locking paper clips of the type which are reversible to lock sheets of paper or the like inserted into the clip and prevent their withdrawal. In order to remove the sheets, the clip is simply reversed to its original position.

B. Prior Art

Various types of reversible locking paper clips are known. However, they all suffer from one or more disadvantages that they are difficult to fabricate, cumbersome in use, or ineffective in purpose.

In one general class of known clips, the clips are formed in generally U-shape and the free ends of the legs of the U are bent to various configurations which are intended to produce a clamping force on sheets inserted between the legs when the clip is reversed. Such clips suffer from the deficiency of difficult fabrication and insufficient gripping force.

In another class of known clips, the clips are formed in generally U-shape with crossed legs. These clips generally suffer from the disadvantage of insufficient gripping force, and to overcome this deficiency the legs are roughened or formed with barbs to increase the gripping effect on the inserted sheets. Despite this, the gripping effect is still weak, and also, the clips are somewhat cumbersome and difficult to handle.

It is also known to modify a conventional paper clip by bending the free ends of the free legs in opposite directions out of the plane of the clip. The resulting clip is disadvantageous in that the position of the locking prongs produces tearing of the inserted paper when the clip is reversed. For heavier thicknesses of paper, the clip does not reverse easily because the free legs must slide laterally and when the legs are stressed this tends to dig the bent free ends into the paper as the clip is being reversed.

SUMMARY OF THE INVENTION

An object of the invention is to provide a reversible paper clip which avoids the deficiencies of the known clips.

Another object of the invention is to provide a reversible paper clip which is relatively simple to manufacture and is easy to use.

Another object of the invention is to provide a reversible paper clip which reliably grips the inserted sheets and exerts a gripping force which will resist substantial application of pulling force tending to remove the sheets from the locked clip and thus without the need for roughening the clamping surfaces.

A further object of the invention is to provide a reversible clip which does not tear the inserted sheets when the clip is reversed.

A further object of the invention is to provide a reversible paper clip which handles and behaves like an ordinary paper clip if the locking feature is not being used.

A further object of the invention is to provide a reversible paper clip in which the sheets can be inserted regardless of whether the clip is in normal or reversed positions.

A further object of the invention is to provide a reversible paper clip in which single sheets of paper or heavy sheets of material such as cardboard or the like can be accommodated.

The paper clip according to the invention comprises a single continuous length of wire having a plurality of bends to define two overlapped sections extending from a common base, each section being of U-shape and including substantially parallel legs, one of the legs of each section extending from said common base, the other of the legs of each section extending between the legs of the other section and parallel thereto, one of said sections being longer than the other such that said other leg of said one section is longer than said other leg of the other section, each of said other legs having ends with bent portions forming an angle with said legs in two directions such that in a first position of the clip, sheets of material can be freely inserted between the legs of said sections whereafter the clip can be turned to cause said bent portions to grip said sheets and prevent withdrawal thereof from said clip.

The clip is turned by raising said one legs from the sheets and turning the clip 180.degree. around the other legs as fulcrums, the bent portions of said other legs being so angled that the bent portion of the shorter leg engages the sheets before the bent portion of the longer leg to enable the longer leg to slide with respect to the point of engagement of the shorter leg with the sheets in the course of turning of the clip.

More specifically, said bent portions extend at a divergent angle from the plane of the clip but at a convergent angle within the plane of the clip.

According to a particular feature of the clip of the invention, said other leg of each section extends substantially midway between the legs of the other section. Additionally, said common base and each said one leg of each section form respective angles which are substantially equal to 90.degree..

According to a further feature of the clip of the invention, said other leg of said other section is disposed centrally of the length of said other leg of said one section in order to provide uniform bearing and counterbearing forces on said other legs of the section as said clip is being reversed.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a front elevation view of the paper clip according to the invention;

FIG. 2 is a side elevation view of the clip;

FIG. 3 is a side elevation view similar to FIG. 2 but showing the clip with sheets of material inserted therein and after the clip has been turned 90.degree. from the position in FIG. 2; and

FIG. 4 is a side elevation view showing the clip in the fully reversed position in which the sheets are locked in the clip.

DETAILED DESCRIPTION

As seen in the drawing, the clip is generally designated by numeral 1 and is constituted by a single length of wire which is formed with right angle bends 2 and 3 from which extend U-shaped sections 4 and 5.

The sections overlap one another and section 4 includes a leg 6 which is perpendicular to base 7 and integrally formed therewith at bend 2 while section 5 includes a leg 8 perpendicular to base 7 and integrally formed therewith at bend 3. Section 4 has a free leg 9 and section 5 has a free leg 10. Section 4 is considered to define a plane of the clip as seen in FIG. 1.

At the free end of leg 9 there is formed a bent portion 11 and at the free end of leg 10 there is formed a bent portion 12. The bent portions 11 and 12 extend upwardly at an angle to the plane of the clip as shown in FIG. 1 so that the bent portions are divergent. In the plane of the clip, the bent portions are convergent as shown in FIG. 1. Hence, each bent portion is inclined in two directions with respect to its associated leg.

Section 4 has a greater length than section 5 and accordingly leg 9 has a greater length than leg 10. Leg 9 extends approximately midway between legs 8 and 10 and leg 10 extends approximately midway between legs 6 and 9.

When the clip is in the configuration as shown in FIGS. 1 and 2, it is a simple matter to insert sheets of paper 13 or the like between the sections 4 and 5 in much the same manner as a conventional paper clip, the sheets being inserted downwardly into the clip in FIGS. 1 and 2. The divergent relation of bent portions 11 and 12 permits unobstructed entry of the paper between sections 4 and 5.

After the sheets 13 have been at least partially inserted between the sections 4 and 5 of the clip, the sheets can be locked in the clip by turning the clip through an angle of 180.degree. so that the clip is reversed. This is achieved by holding the base 7 and turning the clip in a direction to raise leg 6 above the plane of the drawing while lowering the leg 8 below the plane of the drawing. When the clip has been turned 90.degree. it occupies the position as shown in FIG. 3 when viewed from the side. Herein it can be seen that due to the angular relation of the bent portions 11 and 12 they offer no obstruction or resistance to the turning of the clip up to this point. After the clip has reached the 90.degree. position it "springs" into the fully turned position under its own resilience. After the full 180.degree. turn of the clip it occupies the position as shown in FIG. 4 and herein it can be seen that the bent portions 11 and 12 face into the sheets. As a result, they lock the sheets and securely prevent movement of the sheets in the direction of the arrow in FIG. 4. However, the bent portions offer relatively little resistance to further introduction of the sheets into the clip in a direction opposite to the arrow.

In the course of turning the clip, the sections 4 and 5 initially turn or pivot on legs 9 and 10, respectively, as fulcrums. Due to the parallel relation of the legs 6, 8, 9 and 10 and the outward direction of the bent portions 11 and 12, the force applied to the legs 9 and 10 during turning is applied substantially uniformly along the length of the legs. This is insured by the relative positions of legs 9 and 10, namely leg 9 being midway between legs 8 and 10 and leg 10 being midway between legs 6 and 9, and also by the location of leg 10 centrally along the length of longer leg 9. As the clip is being turned, the legs 9 and 10 apply counterbearing forces and due to the proximity of legs 9 and 10, these forces have virtually no tendency to laterally shift the face sheets of the stack as is experienced with conventional reversible clips where the fulcrums are individual points or where the fulcrums are laterally spaced by a substantial distance.

The spacing between the free ends of bent portions 11 and 12 as measured longitudinally along the clip is advantageous in that in the locked position of the clip, the sheets are gripped at longitudinally offset positions which laterally stabilizes the clip on the sheets and resists lateral misalignment of the sheets.

The perpendicular relation between the legs 6 and 8 and base 7 not only enables the clip to clear a thicker stack of sheets, but it also provides relatively rigid corners 2 and 3 which rigidifies the clip in this region and insures turning of the clip around legs 9 and 10 especially when the sheets are made of heavy material and are stacked to a great depth.

It is an important feature of the invention that the bent portion 12 of short leg 10 has a smaller angle of divergence .alpha. as compared to the angle of divergence .beta. of leg 9 so that the sharp edge of portion 12 will bite into the sheets before the edge of portion 11 will do so. In fact, the angle of divergence .alpha. is so adjusted that the edge of bent portion 12 will grip the sheets approximately when the clip reaches its 90.degree. position of turning. Upon further turning of the clip, the leg 10 will serve as a primary retaining leg and leg 9 will slide with respect to the edge of bent portion 12 which now engages the sheets. The leg 9 undergoes a positive spring back to the locking or free position, depending on the direction in which the clip is turned, and assures a perfect and positive positioning and locking of the clip every time.

The angle .theta. which the bent portion 12 makes with the plane of leg 10 is greater than the angle .phi. which bent portion 11 makes with the plane of leg 9 to provide a greater "bite" in the locked position of the clip for bent portion 12.

In order to provide room for deflection of the paper in the locked position of the clip and in order to keep the clip in as close contact with the sheets as possible, the leg 10 is angularly offset by angle .gamma. from the plane of the clip as seen in FIG. 1.

The greater length of leg 9 provides for greater flexibility during turning of the clip and balanced distribution of the clamping force while also it contributes to keep the clip in alignment in the position in which it is applied to the sheets and also permits the clip to lay as flat as possible.

The different angular relation of the bent portions 11 and 12 in two directions are related to each particular function of the respective legs 9 and 10 so as to provide maximum locking capability for a single sheet of paper up to the full clamping capacity of the clip with a minimum of interference of the sharp edges of the bent portions in the course of turning the clip. Damage to the sheets is thereby minimized and distortion of the clip due to stresses developed by the reversing operation are almost nil. Purely by way of example, it has been found that the following values of the angles are particularly effective to achieve easy reversal and effective locking without tearing the sheets or disturbing same: .alpha. = 5.degree.; .beta. = 8.degree.; .gamma. = 2.degree.; .theta. = 15.degree.; and .phi. = 12.degree.. Other geometric relations of significance are: the ratio of length of leg 9 to leg 10 is about 2.5:1; equality of length of bent portions 11 and 12; bent portion 11 is about one-tenth of the length of leg 9 and bent portion 12 is about one-quarter of the length of leg 10; the overall length of the clip (length of leg 6) is about 5 times the width of the clip (length of base 7); and the length of section 4 is about 30 percent greater than the length of section 5.

As a result of the positive and secure locking of the sheets in the clip, there is no necessity for roughening the clamping surfaces as in known clips and in fact such roughening is to be avoided as it could interfere with the otherwise perfect operation of the clip. Moreover, since such roughening is conventionally formed after a protective coating is applied to the wire, this has the effect of locally destroying the coating which would leave the wire bare and subject to rusting which could objectionably mark the paper. This, of course is avoided in the clip of the invention as no surface treatment is effected and the coated wire is used as is.

If the clip should be overstressed, it will take a permanent set which, however, will not interfere with its operability.

By reason of the overlapped relation of the sections 4 and 5 this contributes to a minimum of tangling and interference at the time of manufacture and packaging, especially when compared with conventional open type clips.

The clip can be manufactured from standard paper clip wire and involves no modification in its cross-section over its entire length.

Although the invention has been described with reference to a preferred embodiment thereof, it is to be understood that this is merely given by way of example and variations and modifications thereof will become apparent to those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

What is claimed is:

1. A locking paper clip comprising a single continuous length of wire having a plurality of bends to define two overlapped sections extending from a common base, each section being of U-shape and including substantially parallel legs, one of the legs of each section extending from said common base, the other of the legs of each section extending between the legs of the other section and parallel thereto, one of said sections being longer than the other such that said other leg of said one section is longer than said other leg of the other section, each of said other legs having ends with bent portions forming an angle with said other legs in two directions said one section defining a plane for said clip, said bent portions extending in divergent fashion from said plane of the clip, and extending convergently towards one another in the direction of said base within the plane of the clip, such that in a first position of the clip, sheets of material can be freely inserted between the legs of said sections whereafter the clip can be turned to cause the free ends of said bent portions to grip said sheets and prevent withdrawal thereof from said clip.

2. A clip as claimed in claim 1 wherein said other leg of each section extends substantially midway between and parallel to the legs of the other section.

3. A clip as claimed in claim 1 wherein said common base and each said one leg of each section form respective angles which are substantially equal to 90.degree..

4. A clip as claimed in claim 1 wherein said other leg of said other section is disposed centrally of the length of said other leg of said one section.

5. A clip as claimed in claim 1 wherein said clip is turned by raising said one legs from the sheets and turning the clip 180.degree. around the other legs as fulcrums, the bent portions of said other legs being so angled that the bent portion of the shorter leg engages the sheets before the bent portion of the longer leg to enable the longer leg to slide with respect to the point of engagement of the shorter leg with the sheets in the course of turning of the clip.

6. A clip as claimed in claim 5 wherein the shorter of said other legs is angularly inclined with respect to said plane of the clip.

7. A clip as claimed in claim 5 wherein the bent portion of said shorter other leg is angularly offset from said shorter other leg in the plane of the clip by an angle smaller than the angle by which the bent portion of the longer other leg is angularly offset therefrom in said plane.