IL104252A - Stapler - Google Patents

Description

STAPLER •una The present invention relates to a stapler. More particularly, the present invention relates to a paper stapler for dispensing and driving wide metal staples.

Heretofor prior-art staples worked on essentially the same principle. A staple is pre-formed to a squared inverted U-shape and guided into a slot wide enough to allow passage to the thickness of the wire and just long enough to accommodate the length of the back or web of the staple. A thin ram is positioned over the web of the staple, and moves down to drive the staple, points down, into multiple layers of paper or into a soft solid such as wood, nylon or carton. Where the staple is driven into a thick material, the staple prongs remain straight. If the staple is driven into multiple sheets of paper the prongs of the staple are bent over so as to join together said sheets.

Most staplers are provided with an anvil beneath the ram, the inserted paper sheets to be joined resting on the former. The anvil has depressions situated under the staple points. When the ram forces a staple through the paper, these points strike sloped lower surface of said depression and are bent in (or out) and partially upwards towards the ram. In this way the staple clamps the paper tightly.

Loose staples would be very difficult to load into a stapler, and even if this were achieved they would be unlikely to remain in a single row under compression of the feed spring; so stacks of staples are arranged to be held in straight formation by a light plastic glue just strong enough to retain the staples during loading, and yet not so strong as to interfere in any way with the operation of the ram.

The stack of staples is urged towards the ram by the feed spring. After one staple is pressed into the paper, the ram - 2 - 104,252/2 rises due to a force exerted by the ram lift spring in combination with the user relaxing pressure on the stapler cover, and the remainder of the stack moves forward, a new staple arriving underneath the ram.

As indicated, heretofore staples have been made of steel wire and glued together by lacquer. Due to the rounded edges of the wire, an approximate V-shaped prism is formed between each adjoining pair of staples, this volume being filled with lacquer. Said lacquer usually comprises a fast-drying and easily breakable glue. In operation, the user presses down the upper cover of the stapler; the ram moves down, pushing the leading staple and separating it from an adjacent staple, and breaking the joining lacquer. The stapling action continues, as has been explained above.

Recently, the present inventors have provided a new type of staple, as described and claimed in co-pending Israel Specification 104,251.

According to the invention of said co-pending Specification, there is provided a process for preparing a strip of paper staples from metal sheet or strip material, comprising inserting said material into a die configured to cut all the way through portions of said material without deforming or removing said material, and form said material into at least one strip of a plurality of paper staples having at least one pair of spaced-apart depending paper-engaging prongs and a bridging web connected therebetween, the bridging webs of each of said staples having a width of at least 2 millimeters and a length of at least 6 millimeters, wherein said individual staples are sequentially respectively interconnected by at least one readily frangible segment of non-cut material extending - 2A - 104,252/2 between side surfaces of the webs of adjacent staples, wherein cut and undeformed side surfaces of the webs of adjacent staples abut each other with an imperceptible separation, and imprinting an outer surface of the bridging webs of each of said staples with indicia.

However, since these staples are cut out of a metal strip by means of a die set, and remain attached to each other by leaving at least one contact segment of the organic non-cut metal to form a long strip, the staples need to be separable by breaking said segment or segments by a drive ram which - 3 - shears the joining metal. It was found, however that this could not be achieved by a stapler of known design. As the leading staple has one free edge and one edge still attached to the strip, it was found that the drive ram on pressing down the upper surface of the staple caused rotation of the staple instead of the desired vertical course before the breaking of the contact segments was achieved. The results were abnormal staplings, distorted and broken prongs and staples jammed in the stapler.

In order to ameliorate this problem there is now provided according to the present invention a stapler for dispensing and driving staples from a strip of a plurality of wide paper staples of the type having at least one pair of spaced-apart depending paper-engaging prongs and a bridging web connected therebetween. Said bridging web of each of said staples has a width of at least 2 millimeters and a length of at least 6 millimeters. The individual staples are sequentially respectively interconnected to an adjacent staple by at least one readily-frangible segment of non-cut material extending therebetween, and have been formed from metal sheet or strip material.

This stapler is provided with a cutting drive ram for shearing said frangible segment interconnecting a first staple to be dispensed and a second adjacent staple; a staple dispensing slot of a width to allow passage to a single staple; a staple guiding surface forming the front face of said slotp; and at least one retractable support element protruding from said guiding surface into said dispensing slot to support the free leading edge of the bridging web of a first staple during shearing of said frangible segment. Thereafter said support element is retracted and the ram drives the first staple through said slot. - 4 - In preferred embodiments of the present invention said support element is spring biased.

In a first preferred embodiment of the present invention said support element comprises a first triangular plate-like support member with a wide base, the apex surface thereof serving as an initial support surface for the edge of said staple web, said support member being retracted as the first staple is driven towards said base along an inclined edge of the support member.

In an especially preferred embodiment of the present invention said support element further comprises a second but inverted triangular plate-like member, the apex thereof being contiguous with the apex of the first support member, the free leading edge of the first staple being initially-retained at the juncture of the two apices during the shearing of the frangible segment.

In a most preferred embodiment of the present invention there is provided a stapler for dispensing and driving staples from a strip of a plurality of wide paper staples of the type wherein said individual staples are sequentially respectively interconnected to an adjacent staple by two spaced-apart readily frangible segments of non-cut material extending between side surfaces of the webs of adjacent staples. This stapler is provided with two retractable spaced-apart support elements protruding from a guiding surface into the dispensing slot to support the free leading edge of the bridging web of a first staple during shearing at points substantially opposite to the two spaced-apart frangible segments.

It will thus be realized that the novel stapler of the present invention serves to: a) hold the staple's free edge in the right position; - 5 - b) avoid upward movement of the staples; c) avoid rotation of the staple at the moment of separation and shearing of the contact segments; and d) maintain the staple in a vertical orientation until completion of the stapling operation.

The invention will now be described in connection with certain preferred embodiments with reference to the following illustrative figures so that it may be more fully understood.

With specific reference now to the figures in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

In the drawings: Pig. 1 shows a perspective fragmented view of an open loaded stapler according to a first embodiment of the invention; Fig. 2 is a detailed plan view of a preferred embodiment showing a biasing spring acting on the support element; Fig. 3 shows a perspective, fragmented detail of a triangular support member as used in a further preferred embodiment of the stapler; - 6 - Fig. 4 is also a perspective, fragmented detail, of a twin-triangular support member in an especially preferred embodiment of the stapler; Fig. 5 is a fragmented perspective view of a most preferred embodiment of a stapler loaded with a strip of wide paper staples of the type wherein said individual staples are interconnected to an adjacent staple by two frangible segments; and Fig. 6 is a perspective, fragmented view of a U-shaped ram as used on a stapler according to the invention.

There is seen in Fig. 1 a stapler 10 for the dispensing and driving wide staples 12 from a strip 14 of such staples. The staple 10 is shown loaded with a strip 14. The staples 12 are of the type having one pair of spaced-apart depending paper-engaging prongs 16 and a bridging web 18 connected therebetween. The bridging web 18 has a width of at least 2 millimeters and a length of at least 6 millimeters. The staples 12 are sequentially respecitvely interonnected to an adjacent staple by one readily-frangible segment 20 of non-cut material extending therebetween, the staples 12 having been formed from a metal sheet or strip material.

The stapler 10 is provided with a cutting drive ram 22 for shearing the frangible segment 20 interconnecting a first staple 12 to be dispensed and driven, and a second adjacent staple 12'. The cutting drive ram 22 shown in this embodiment is of rectangular cross-section. However unlike prior art staplers, the ram 22 has substantial thickness, at least 2 mm, the ram therefore having superior rigidity and providing better guidance to the staple 12 being driven than the thin ram which must be used on prior art staplers.

The stapler 10 has a staple dispensing slot 24 of a width and breadth to allow passage to a single staple 12. A staple guiding surface 26 forms the front face of the slot 24.

Protruding from the surface 26 into the slot 24 is a retractable support element 28. When staples are held by the stapler, the support element 28 supports the free leading edge 30 of the bridging web 18 of a first staple 12 during shearing of the frangible segment 20, whereafter the support element 28 is retracted and the ram 22 drives the first staple 12 through the slot 24.

A foamed urethane pad 32 is shown urging the support element 28 into the slot 24; during the passage of a staple 12 the pad 32 is compressed by the passing staple 12.

In operation the support element 28 serves to hold the staple's free leading edge 30 in its correct position. Thereby, any possible upward movement of the staple strip 14 is avoided, and even more importantly, possible rotation of the staple 12 at the moment of separation and shearing of the segment 20 is also prevented. The wide ram 22 also contributes to maintaining the staple 12 in a vertical orientation until completion of the stapling operation.

Other components of the stapler are similar to those on known staplers and require no description.

Fig. 2 shows a detail of a preferred embodiment 34 of a further stapler. The support element 28 is shown to be spring biased, the spring 34 shown being a short compression spring.

In further embodiments (not shown) a leaf spring or a dished washer are used instead of the compression spring 34. The spring 34 has improved durability in comparison with the pad 32.

Fig. 3 shows a triangular support member 36 as used in a further preferred embodiment 38 of the stapler, a detail of which is shown. A first triangular plate-like support - 8 - member 36 is provided with a wide base 40, the apex surface 42 of the member 36 serving as an initial support surface for the staple edge 30. In operation the support member 36 is retracted as the first staple 12 is driven towards the base 40 along an inclined edge 44 of the support member 36.

Fig. 4 shows a twin-triangular support member 46 in a detail of an especially preferred embodiment of a stapler 48. Here the support element further comprises a second but inverted triangular plate-like member 50, the apex 52 thereof being contiguous with the apex surface 42 of the first support member 36 described with reference to Fig. 3. In operation the free leading edge 30 of the first staple 12 is initially retained at the juncture of the two apices 42, 52 during the shearing of the frangible segment 20 shown in Fig. 1.

There is seen in Fig. 5 a stapler 54 loaded with a strip 56 of wide paper staples 58 of the type wherein said individual staples are sequentially respectively interconnected to an adjacent staple 58' by two spaced-apart readily frangible segments 60 of non-cut material extending between side surface of the webs 62 of adjacent staples. The staple 58 has two pairs of spaced-apart depending paper-engaging prongs 64 and a bridging web 62 connected therebetween.

The stapler 54 is provided with two retractable spaced-apart support elements 66 protruding from a guiding surface 68 into a dispensing slot 70 to support the free leading edge 72 of the bridging web 62 of a first staple 58 during shearing, this support being provided at points substantially opposite to the two spaced-apart frangible segments 60. As is to be expected, the provisions of two spaced-apart support elements 66 makes an important contribution to stabilizing the staple 58 during the stapling operation. - 9 - Fig. 6 shows part of a stapler 74 wherein the cutting drive ram 76 is of U-shaped cross-section. The base 78 of said U is positioned over the attached side of the staple 58 and in operation acts to shear the frangible segments 60, while the arms 80 of the U stabilize the staple. As will be realized, the U-shaped ram 76 is easily manufactured as a sheet steel pressing. Advantageously the ram 76 may be provided with a slightly sloped lower face 82, the higher edge 84 of said face being above the free edge 86 of the staple 58.

In operation such a ram will act to first shear the frangible segments 60 before attempting to drive down the staple 58. The sloped face 82 will furthermore assist in counteracting the tendency of the first staple 58 to rotate its prongs 64 inwards towards the adjacent staple 58'. A slope in the range of 2 to 5 degrees is all that is needed to achieve these advantages.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the essential attributes thereof, and it is therefore desired that the present embodiments be considered in all respects as illustrative and not restrictive, reference being made to the appended claims, rather than to the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (9)

- 10 - 104,252/2 WHAT IS CLAIMED IS:

1. A stapler for dispensing the driving staples from a strip of a plurality of wide paper staples of the type having at least one pair of spaced-apart depending paper-engaging prongs and a bridging web connected therebetween, the bridging webs of each of said staples having a width of at least 2 millimeters and a length of at least 6 millimeters, wherein said individual staples are sequentially respectively interconnected by at least one readily frangible segment of non-cut material extending between side surfaces of the webs of adjacent staples, wherein cut and undeformed side surfaces of the webs of adjacent staples abut each other with an imperceptible separation, said staples having been formed from a metal sheet or strip material, said stapler being provided with: a cutting drive ram for shearing said frangible segment interconnecting a first staple to be dispensed and a second adjacent staple; a staple dispensing slot of a width to allow passage to a single staple; a staple guiding surface forming the front face of said slot; and at least one retractable support element protruding from said guiding surface into said dispensing slot to support the free leading edge of the bridging web of a first staple during shearing of said frangible segment, whereafter said support element is retracted and said ram drives said staple through said slot.

2. The stapler as claimed in claim 1, wherein said support element is spring biased. - 10A - 104,252/2

3. The stapler as claimed in claim 1, wherein said support element comprises a first triangular plate-like support member with a wide base, the apex surface thereof serving as an initial support surface for the edge of said staple web, - 11 - said support member being retracted as said first staple is driven towards said base along an inclined edge of said support member.

4. The stapler as claimed in claim 3, wherein said support element further comprises a second but inverted triangular plate-like member, the apex thereof being contiguous with the apex of said first support member, said free leading edge of said first staple being initially retained at the juncture of the two apices during the shearing of said frangible segment.

5. The stapler as claimed in claim 1, for dispensing and driving staples from a strip of a plurality of wide paper staples of the type wherein said individual staples are sequentially respectively interconnected to an adjacent staple by two spaced-apart readily frangible segments of non-cut material extending between side surfaces of the webs of adjacent staples, said stapler being provided with two retractable spaced-apart support elements protruding from said guiding surface into said dispensing slot to support the free leading edge of the bridging web of a first staple during shearing at points substantially opposite to said two spaced-apart frangible segments.

6. The stapler as claimed in claim 1, wherein said cutting drive ram is of rectangular cross-section.

7. The stapler as claimed in claim 1, wherein said cutting drive ram is of U-shaped cross-section.

8. The stapler as claimed in claim 1, wherein said cutting drive ram is provided with a sightly sloped lower face, the higher edge of said face being adjacent to said staple guiding surface.

9. A stapler for dispensing and driving staples from a strip of a plurality of wide paper staples, substantially as - 12 - described hereinbefore and with reference to the accompanying drawings. For the Applicant WOLFF, BREGMAN AND GOLLER