GB2231831A - Scissors - Google Patents

Abstract

The invention has for its objective the avoidance of those complex and expensive aspects of conventional scissors where the blades are either formed from a generally tapered blank or stock material and ground to provide a cutting edge, or the outside face of the stock is bevel ground to provide a generally tapered surface and to form the cutting edge. This objective is met by each blade being formed from parallel sided stock flat ground with a first angled face 6 to provide a tapered portion extending towards a respective cutting edge, one at least of said blades being further ground with a second angled face 7 to create said cutting edge said second angled face having a serrated configuration 9 transversely of said second angled face. The serrations preferably have a pitch of sixty teeth per inch and an included angle between the flanks of 70 degrees. The face 6 is preferably at an angle of 27 degrees and the face 7 at an angle of 65 degrees, to the outer face of the blade. Preferably both blades have second angled faces, only one of which is serrated. <IMAGE>

Description

SCISSORS This invention relates to scissors.

Conventionally scissors comprise two blades pivotally secured together with the blades extending to a respective thumb grip and finger grip to one side of the pivot. To the opposite side of the pivot the blades are of generally tapered configuration from a respective back edge to a respective cutting edge, and ordinarily the two blades set with respect to each other such that from a fully open position a pressure exists between the respective cutting edges as the blades are progressively closed.

The provision of a generally tapered blade from its back edge to its cutting edge can be consequent upon the provision of a tapered blank suitably ground to provide the cutting edge but the provision of tapered blanks is relatively expensive. Equally it is known to bevel grind what is to be the outer surface of a blank to provide the generally tapered section, but bevel grinding is both complex and expensive.

Particularly with domestic scissors a considerable variety of materials are frequently required to be cut, frequently leading to the blunting of the cutting edges and the need for reshaping, and with conventional scissors they can be somewhat ineffective or difficult to use on materials where there is a tendency for the material to slide in advance of the cutting point at the intersecion between the two blades as it progresses from the open to the closed condition.

It is the object of the present invention to provide a pair of scissors that avoids the disadvantages referred to above.

According to the present invention, a pair of scissors comprises two blades pivotally secured together with the blades extending two a respective thumb gripandfinger grip to one side of the pivot and the blades to the opposite sides of the pivot each being provided with a cutting edge, each blade being formed from parallel sided stock flat ground with a first angled face to provide a tapered portion extending towards a respective cutting edge one at least of said blades being further ground with a second angled face to create said cutting edge said second angled face having a serrated configuration transversely of said second angled face.

Preferably, both of said blades are ground with a second angled face one of which is provided with serrations and the other of which is left blank.

Thus, by employing parallel sided stock the cost factors in the production of blades is considerably reduced in comparison with those prior art constructions emplying tapered stock and by flat grinding parallel sided stock there is again a noticeable reduction in costs in comparison with those bevelled gound constructions known in the prior art.

As a consequence of at least one of the blades of the scissors of the invention having a second serrated angled face leading directly to the cutting edge, not only does the presence of the serrations add considerably to the sharpness of the cutting edge, to the effectiveness of the cutting action and to the retention of the cutting edge, but also the presence of the serrations causes the material to be cut to be gripped by the blades and thereby prevent the material from sliding along the blades in advance of the cutting point between the blades are the blades are progressively closed.

It is highly desirable that fine serrations are provided on the second angled face of at least one of the blades as predominently the cut required to be performed by the scissors needs to be cleaned or scraped thus it is preferred to employ serrations having a pitch of between 58 and 70 teeth per inch, and further preferably 68 teeth per inch, and an included angle between the flanks of the serrations of 600 to 10Bo and preferably 700.

Preferably, the first angled face on each blade lies at 200 to 400 to the face of the blade on which the first flat ground face is formed and further preferably at 270, and the second angled face lies at 600 to 900 to the said face of the blade, and preferably at 650.

The thumb grip and finger grip on the respective blades may be formed integrally with the blades or may be separately formed such as from an appropriate plastics material and attached to tangs formed on the blades to one side of the pivot. In common with conventional scissors, the blades between the pivot and the tip may be set such as to provide pressure between the blades as the cutting point between the blades progresses from the fully open to the fully closed condition, and again in common with conventional scissors relief may be provided behind the cutting edge of each blade by forming the facing faces of the blades of hollowed configuration.

Several embodiments of the invention are illustrated by way of example only, in the accompanying drawings, in which: Figure 1 is a plan view of a pair of dressmaking scissors according to the invention; Figures 2 and 3 are views on arrows A and B respectively of Figure 1; Figures 4 and 5 are sections on lines C-C and D-D respectively of Figure 1; Figure 6 is an end view of the scissors of Figure 1; Figures 7 and 8 are respectively plan views of general purpose scissors and kitchen scissors according to the invention, where the views on arrows A and B, and the sections C-C and D-D and the end views generally correspond to Figures 2 and 6 respectively; Figure 9 is a plan view of a pair of embroidery scissors according to the invention; Figure 1~ is a side view of the scissors of Figure 9;; Figure 11 is a section on the line E-E of Figure 9; Figure 12 is an end view of the scissors of Figure 9; Figures 13 and 14 are plan views of small general purpose and sewing scissors respectively, and where the side views, the sections on the line E-E, and the end views, generally correspond to Figures 18 to 12 respectively; Figure 15 is a section through the serrated blades of the foregoing Figures; and Figure 16 is an enlarged fragmentary view of a part of the serrated edge of the blades of the foregoing Figures.

In the drawings, and for convenience, like parts are given the same reference numbers. Thus, the scissors comprise two blades 1, 2, pivotted together at 3 and extending beyond the pivot to respective thumb and finger handles 4 and 5.

Each blade 1, 2 is formed from parallel-sided stock, and each blade is angle ground at 6 to provide a cutting edge to one side of the blade.

As is shown more particularly by Figures 15 and 16, the blade 1 is further ground at its cutting edge with a second angled face 7 to provide the cutting edge substantially co-planar with the inside face 8 of the blade, and the angled face 7 is formed with fine serrations 9.

For optimum performance, the fine serrations have a pitch of 60 teeth per inch and an included angle between the flanks of the serrations of 700. Preferably, the first angled face 6 on each blade is at 270 to the outside face of the blade, and the second angled face bearing the serrations is preferaby at 650 to the flat outside face of the blade.

In common with conventional scissors, the blades 1, 2 from the pivot 3 to the tip, should be set such as to provide pressure between the blades as the cutting point between the blades progresses from the fully open to the fully closed condition, and again in common with conventional scissors, relief as is indicated at 1~ in Figure 15 should be provided behind the cutting edge of each blade, such as by forming the faces of the blades of hollowed configuration.

Claims (11)

1. A pair of scissors comprising two blades pivotally secured together with the blades extending to a respective thumb grip and finger grip to one side of the pivot and the blades to the opposite sides of the pivot each being provided with a cutting edge, each blade being formed from parallel sided stock flat ground with a first angled face to provide a tapered portion extending towards a respective cutting edge one at least of said blades being further ground with a second angled face to create said cutting edge said second angled face having a serrated configuration transversely of said second angled face.

2. A pair of scissors as in Claim 1, wherein both of said blades are ground with the second angled facce, one said second angled face being provided with serrations and the other being left blank.

3. A pair of scissors as in Claim or Claim 2, wherein the said serrations are fine serrations having a pitch of between 50 and 70 teeth per inch.

4. A pair of scissors as in Claim 3, wherein the said serrations have a pitch of 60 teeth per inch.

5. A pair of scissors as in any of Claims 1 to 4, wherein said serrations have an included angle between the flanks of 68o to l##o.

6. A pair of scissors as in Claim 5, wherein said included angle is 700.

7. A pair of scissors as in any of Claims 1 to 6, wherein said first angled face on each blade lies at 200 to 400 to the outside face of the blade.

8. A pair of scissors as in Claim 7, wherein said first angled face is at 270 to the outside face of the blade.

9. A pair of scissors as in any of Claims 1 to 8, wherein said second angled face lies at 600 to 900 to the outside face of the blade.

1~. A pair of scissors as in Claim 9, wherein said second angled face lies at 650 to the outside face of the blade.

11. A pair of scissors substantially as hereinbefore described with reference to any one of the accompanying drawings.