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Title:
MULTI-PURPOSE BLADE SHEARS
Document Type and Number:
WIPO Patent Application WO/2014/209134
Kind Code:
A1
Abstract:
The invention relates to a pair of blade shears (1), including a first blade (2) and second blade (6), each blade having a respective handle (5, 9), and a biasing device (19) configured to connect the first handle (5) to the second handle (9). The biasing device is configured to apply a force to the first handle (5) and/or the second handle (9), the force biased to push the first handle and the second handle apart in a plane of the first blade (2) and first handle (5). The second handle (9) is pivotally mounted to the biasing device (19), the pivot axis (29) lying substantially in the plane of the first blade and the first handle.

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Inventors:
WATSON RICHARD PAUL (NZ)
Application Number:
PCT/NZ2014/000124
Publication Date:
December 31, 2014
Filing Date:
June 24, 2014
Export Citation:
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Assignee:
WATSON RICHARD PAUL (NZ)
International Classes:
B26B13/04
Foreign References:
US4326335A1982-04-27
US4089113A1978-05-16
NZ280562A1997-02-24
AU1046292A1992-07-30
Attorney, Agent or Firm:
JAMES & WELLS et al. (KPMG Centre85 Alexandra Street, Hamilton 3240, NZ)
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Claims:
WHAT I CLAIM IS:

1. A pair of blade shears including: a first blade having a cutting surface bounded on one side by a cutting edge; a first handle connected to the first blade; a second blade having a cutting surface bounded on one side by a cutting edge; a second handle connected to the second blade; and a biasing device configured to connect the first handle to the second handle, the biasing device located at or in the vicinity of an end of the first handle distal to the blade end of the first blade; wherein the biasing device is configured to apply a force to the first handle and/or the second handle, the force biased to push the first handle and the second handle apart in a plane of the first blade and first handle, and wherein the second handle is pivotally mounted to the biasing device, the pivot axis lying substantially in the plane of the first blade and the first handle.

2. A pair of blade shears as claimed in claim 1 wherein the first blade is releasably

attached to the first handle.

3. A pair of blade shears as claimed in either one of claims 1 or 2 wherein the second blade is releasably attached to the second handle.

4. A pair of blade shears as claimed in any one of claims 1 to 3 wherein the cutting surface of the first blade includes a first portion that is substantially flat and extends from the vicinity of a front end of the first blade to the vicinity of a rear end of the first blade, and a second portion that is bounded on one side by the first portion and on another side by the cutting edge, wherein the second portion is substantially flat and inclined with respect to the first portion.

5. A pair of blade shears as claimed in any one of claims 1 to 4 wherein the cutting surface of the second blade is configured into a first portion that is substantially flat and extends from the vicinity of a front end of the second blade to the vicinity of a rear end of the second blade, and a second portion that is bounded on one side by the first portion and on another side by the cutting edge, wherein the second portion is substantially flat and inclined with respect to the first portion.

6. A pair of blade shears as claimed in any one of claims 1 to 5 wherein the biasing device includes a hub having a hub axle, the hub including a first attachment portion configured to connect to the first handle and a second attachment portion configured to connect to the second handle.

7. A pair of blade shears as claimed in claim 6 wherein the first handle is attached to the first attachment portion of the hub and the second handle is attached to the second attachment portion such that the cutting surfaces of the first blade and the second blade face one another when the shears are in a closed position.

8. A pair of blade shears as claimed in either one of claims 6 or 7 wherein an end of the second handle distal to the end having the second blade is configured to attach to the second attachment portion of the hub, the attachment including a hub pivot.

9. A pair of blade shears as claimed in claim 8 wherein the second blade and handle can move in and out of the plane of the first blade and handle using the hub pivot, the pivot axis of which lies in the plane of the first blade and handle.

10. A pair of blade shears as claimed in either one of claims 8 or 9 wherein the second handle includes a second biasing means configured to act on the hub in the vicinity of the hub pivot to bias the cutting surface of the first blade to move towards the cutting surface of the second blade and wee versa.

11. A pair of blade shears as claimed in claim 10 wherein the second biasing means is a spring.

12. A pair of blade shears as claimed in any one of claims 1 to 11 wherein the pair of blade shears includes a handle lock configured to lock the first handle and the second handle together when in a closed position, and to allow the first handle and the second handle to move when in an open position.

13. A pair of blade shears substantially as herein described and illustrated with reference to the accompanying description and drawings.

Description:
MULTI-PURPOSE BLADE SHEARS

TECHNICAL FIELD

The present invention relates to shears, and in particular to blade shears used to cut wool, fur, or hair from a sheep, goat, cow, alpaca, llama, yak, dog or other animal. The multi-purpose blade shears may also be used for trimming and cutting of plant material and any other shearing or cutting use. However, there may be many uses for the shears so that the above list of uses should not be seen as limiting.

BACKGROUND ART Shears have numerous uses in practice, including use to cut wool, fur, or hair from a sheep, goat, cow, alpaca, llama, yak, dog or other animal. Shears may also be used for trimming and cutting plant material as well as many other uses.

In the following the use of shears is mainly described in their use in shearing sheep and other animals. However, those skilled in the art will appreciate that this is but one example of the use of shears, and that reference to shears for shearing sheep and other animals only throughout this specification should not be seen as limiting.

Traditionally sheep and other animals have been shorn by hand using a pair of blade shears. More recently machine blades have become common for shearing, but hand operated blade shears are still used globally for removal of wool, fur and hair from many animal species, and also used for dagging and crutching sheep. Blade shears normally have two blades, each connected to a handle, where the handles are connected at, and pivot about, a point near the rear end (i.e. the end distal to the blade end) of the shears, essentially behind a hand of a user. This is in contrast to a pair of scissors, for example, which also consist of a pair of blades, each one connected to handle, but the connection and pivot point for a pair of scissors is near the middle of the scissors, and in front of a hand of a user.

Blade shears are typically made out of steel, the blades being hollow ground from high carbon steel, and the handles made from sprung steel. Each handle and attached blade is normally formed as a single item (much as with scissors) and the handles are typically riveted together towards the rear end of the handle. The handles have a characteristic shape, having a relatively straight section (which is formed to accommodate the hand of a user) before curving away from the straight section into an arc which turns back on itself towards the blade end of the shears, the arc terminating around an imaginary central line of the blade shears. The blade shears are formed by riveting together the ends of the arcs of each handle. This arrangement

l has the advantage that the rivet, which could otherwise catch on clothing, hands etc, is tucked out of way in the interior of the blade shears.

One of the blades (typically the lower blade in use) has a guide ("coxspur") which assists to hold the two sprung blades together in use. The high carbon steel blades are initially formed with a straight blade. However, the blades can quickly become bent into a curved shape due to wear and tear in a shearing environment, e.g., through being dropped, stood on, or whatever. The shears are designed to work efficiently with a straight blade; hence when the blade becomes bent the cutting action is less effective.

Furthermore, the bent blades cause the blades to run apart (i.e. contact between the cutting edges only occurs in a small portion of the blade at any one time, as to along the blades when straight) which can lead to the blades going blunt more quickly than otherwise.

Thus a problem with existing shears is that they require frequent maintenance to sharpen the cutting edges and to straighten the bent blades. This can be a relatively difficult and costly operation; the shears cannot be used while maintenance is carried out on the bent or blunted blades, and more shears than would normally be required must be provided if work is to continue.

Furthermore, the blades of the prior art blade shears cannot be replaced. If a blade becomes so damaged that maintenance would be too costly or time consuming, they need to be replaced with a new pair of blade shears which adds to the cost and may be inconvenient, especially if a new set is not immediately available and has to be ordered in.

Another problem with the prior art shears is that they can be difficult to use. The basic design has been used for many years without any real improvement, and particularly without any consideration of ergometric design to improve the ease of use.

In order to operate the blade shears it is necessary for a user to use a clenching motion of the hand on the handles and, simultaneously, to apply a shearing force to hold the cutting edge of one of the blades against the cutting edge of the other blade. This motion can cause problems to the user, especially following prolonged repetition, and more so when the blades become bent or blunt.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

Throughout this specification, the word "comprise", or variations thereof such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only. DISCLOSURE OF THE INVENTION

According to one aspect of the present invention there is provided a pair of blade shears including: a first blade having a cutting surface bounded on one side by a cutting edge; a first handle connected to the first blade; a second blade having a cutting surface bounded on one side by a cutting edge; a second handle connected to the second blade; and a biasing device configured to connect the first handle to the second handle, the biasing device located at or in the vicinity of an end of the first handle distal to the blade end of the first blade; wherein the biasing device is configured to apply a force to the first handle and/or the second handle, the force biased to push the first handle and the second handle apart in a plane of the first blade and first handle, and wherein the second handle is pivotally mounted to the biasing device, the pivot axis lying substantially in the plane of the first blade and the first handle. It is appreciated that the blade and handle are 3D objects and as such do not lie in a single plane. However, for the purposes of this specification the plane of the blade and handle should be taken generally to mean a plane though the blade and handle substantially parallel to the plane of a flat surface on which a side of the blade and handle is laid.

A feature of the pair of blades of the present invention is that one of the blades is pivoted relative to the other blade so that the blades can be brought together with the cutting edge of one blade in contact with the cutting edge of the other blade (pivot angle 0°), or the blades can be opened so that there is an angle between the plane of the first blade and a plane of the second blade. An advantage of this arrangement is a user may use the pivot to relatively easily bring the two blades together, and keep them together, to make a cut. This may be considerably less tiring on a user and require less skill than the twisting and shearing motion required to operate blade shears of the prior art. In a preferred embodiment the first blade is releasably attached to the first handle.

In a preferred embodiment the second blade is releasably attached to the second handle.

It may be any advantage to provide a pair of blade shears in which used or damaged blades can be replaced without having to replace the remainder of the blade shears. This may be cheaper, quicker and more convenient than the full replacement required of the prior art devices in the same situation.

It will be known to the person skilled in the art that the blade must be fixed firmly to the handle in order for the blade shears to function properly. Therefore the term "releasably" as used above should be understood to mean that the blades can be removed from the handles without destroying the blades or the handles, and new blades can be fitted to the handles to provide a working pair of shear blades with new blades.

In this case releasable attachments may include (without limitation) screwing, bolt and nut or any other method of releasable attachment as well known in the field.

In a preferred embodiment the cutting surface of the first blade includes a first portion that is substantially flat and extends from the vicinity of a front end of the first blade to the vicinity of a rear end of the first blade, and a second portion that is bounded on one side by the first portion and on another side by the cutting edge, wherein the second portion is substantially flat and inclined with respect to the first portion.

In a preferred embodiment the cutting surface of the second blade is configured into a first portion that is substantially flat and extends from the vicinity of a front end of the second blade to the vicinity of a rear end of the second blade, and a second portion that is bounded on one side by the first portion and on another side by the cutting edge, wherein the second portion is substantially flat and inclined with respect to the first portion.

In a preferred embodiment the biasing device is a hub having a hub axle, the hub including a first attachment portion configured to connect to the first handle and a second attachment portion configured to connect to the second handle, wherein the first attachment portion and the second attachment portion are connected to the hub axle such that the hub axle acts as a pivot for the first attachment portion and independently for the second attachment portion.

In a preferred embodiment the hub includes a biasing means configured to bias the first attachment portion to move away from the second attachment portion and vice versa. In a preferred embodiment the biasing means is a coil spring.

When assembled the first handle is attached to the first attachment portion of the hub and the second handle is attached to the second attachment portion such that the cutting surfaces of the first blade and the second blade face one another when the shears are in a closed position (i.e. the biasing force of the bub has been overcome to bring the first attachment portion to a closed position close to the second attachment portion).

Preferably the pair of blade shears includes a handle lock configured to lock the first handle and the second handle together when in a closed position, and to allow the first handle and the second handle to move when in an open position. The closed position of the handle lock can only be operated when the blades are in the closed position.

Preferably an end of the second handle distal to the end having the second blade is configured to pivotally attach to the second attachment portion of the hub, using a hub pivot having a pivot axis which lies in the plane of the first blade and handle.

In this arrangement the second blade and handle can move in and out of the plane of the first blade and handle about the hub pivot, the pivot axis of which lies in the plane of the first blade and handle.

Preferably the second handle includes a recess located in the vicinity of the hub pivot, the recess configured to locate a second biasing device, wherein the second biasing device provides a biasing force pushing the cutting surface of the first blade toward the cutting surface of the second blade and vice versa.

Preferably the second biasing device is a compression spring.

BRIEF DESCRIPTION OF THE DRAWINGS

Further aspects of the present invention will become apparent from the ensuing description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1 shows a view of a pair of blade shears according to one embodiment of the present invention;

Figure 2 shows a side view of a blade according to one embodiment of the present

invention; Figure 3 shows a cross sectional view of a blade shown in Fig.2; and

Figure 4 shows a view of part of the pair of blade shears of the embodiment shown in BEST MODES FOR CARRYING OUT THE INVENTION

A pair of blade shears according to one embodiment of the present invention is generally indicated by arrow 1 in Fig. 1. The blade shears include a first blade 2 having a cutting surface 3 bounded on one side by a cutting edge 4. A first handle 5 is connected to the first blade. The blade shears also include a second blade 6 having a cutting surface 7 bounded on one side by a cutting edge 8. A second handle 9 is connected to the second blade.

The first and second blades are formed from 2D stainless steel. This is much stronger, has greater durability, and retains a sharp cutting edge much longer than the high C steels used in the prior art blade shears. For example, the cutting edge of the present invention may remain sharp during operations on around 50 sheep, as against around 3 sheep for the prior art shears. This may significantly reduce time and labour costs for maintenance of the cutting edges, providing much enhanced efficiency and less inconvenience to the user.

The blades 2, 6 and the handles 5, 9 respectively, are attached together by Allen key screws 10. These can be removed to release the blade from the handle so that a new blade can be fitted as required. This may provide a considerable saving in maintenance time and cost, especially as with the prior art blade shears the blades cannot be replaced; failure of one blade means the pair of blades are disposed of.

The form of the blades in one embodiment of the present invention may further enhance the operation of the blade shears. As shown in Fig. 2, the cutting surface (i.e. the interior surface of the blade when assembled as a pair of blade shears) of blade 11 is formed in two portions; a first portion 12 and a second portion 13. The first portion is flat and extends from the front end of the blade 14 to the rear end 15. The first portion extends across the blade from a top side of the blade 16 to a fold 17 in the blade. The second portion is also flat, and is bounded on one side by the fold 17 and on the other side by a cutting edge 18. A cross-sectional view through the blade 11 is shown in Fig. 3, which clearly shows the fold 17 which separates the first portion 12 from the second portion 13. It also clearly shows that the second portion is inclined with respect to the first portion.

When the blades are assembled to form the shears, two such blades are located with their cutting surfaces facing one another (i.e. both cutting surfaces form interior surfaces of the shears). In this arrangement the inclination of the cutting edges means that when the blades move past one another to make a cut, it is only the cutting edges that are in contact; the remaining portions of the blade (first portion 12 and most of second portion 13) being spaced apart from one another. This may reduce the friction between the blades which may make the shears of the present invention more easy to use. The pair of blade shears according to the present invention include a biasing device, shown in Fig.1 in the form of a hub 19 located at or near the end of the blade shears distal to the blade end. The hub includes a hub axle 20 and a first attachment portion 21 configured to connect the first handle 5 to the hub 19. Handle 5 and hub 19 are arranged so that there are two acetal plastic bearings between the two, the arrangement held together by bolt and a lock tight nut (not shown). The hub, on the nut side, is configured to be substantially the same shape and size of the nut, so that the nut and bolt can not turn in relation to handle 5. The hub 19, on the bolt side, is configured so that the top of the bolt can turn in relation to the hub 19. A fixed washer (not shown) between the bolt and hub facilitates rotational movement of the bolt with respect to the hub.

The hub also includes a second attachment portion 22. The first attachment portion and the second attachment portion are connected to the hub axle such that the hub axle acts as a pivot for the first attachment portion and independently for the second attachment portion

The second attachment portion 22 is in the form of a hub pivot formed by pivot pin 23, cylinder 24 on the second attachment portion and apertures 25 and 26 on lugs 27 and 28 respectively, as shown in more detail in Fig. 4.

As can be seen in Fig. 1 the pivot axis, indicated by dashed line 29, lies in a plane of the first blade 2 and first handle 5 and is oriented substantially at a right angle to a longitudinal axis of the second handle and second blade. The hub pivot includes a second biasing device in the form of a compression spring 35 located in a recess 36 in the second handle 9, the compression spring biased to push the cutting surface 3 of the first handle 5 towards the cutting surface 8 of the second handle 9 and vice versa, the force being applied in a plane of the hub at right angles to the hub axle 20, i.e. a plane of the first blade and the first handle. The pair of shears includes a handle lock in the form of a locking device 30 on the second handle 9 which engages with an aperture 31 in the first handle 5 when the blade shears are in the closed position. The locking device consists of a lug 32 which can slide along a groove (not shown) in the second handle. Typically the locking device is manually operated as required.

The first handle 5 includes a rest 33 designed to improve a user's ability to operate the blade shears.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.




 
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