WO2013076643A1

WO2013076643A1 - Knife arrangement

Info

Publication number: WO2013076643A1
Application number: PCT/IB2012/056555
Authority: WO
Inventors: Theodor Martins
Original assignee: Theodor Martins
Priority date: 2011-11-21
Filing date: 2012-11-20
Publication date: 2013-05-30

Abstract

The invention discloses a knife arrangement for folding knives, which includes a handle including a first handle plate and a second handle plate, the first handle plate and the second handle plate being connected together by means of a pivot pin; a lockable folding blade pivotally mounted around the pivot pin of the handle; a slot in the folding blade adapted to receive a bush member adapted to rotate around the pivot pin; the handle and the folding blade having an upper side and a lower side; biasing means, such as a spring, in the slot for urging the folding blade towards the lower side and locked position; a locking lug in the upper side of the folding blade; and at least one catch in the first handle plate or the second handle plate in the upper side of the handle for engaging the locking lug.

Description

KNIFE ARRANGEMENT

FIELD OF INVENTION

The present invention relates to a knife arrangement.

More particularly, the present invention relates to a knife arrangement for folding knives incorporating a locking arrangement.

BACKGROUND TO INVENTION

A pocket knife is a type of folding knife having at least one blades adapted to fit inside the handle capable of fitting inside a pocket. Pocketknives are versatile tools and are used for anything from opening an envelope, to cutting twine, to slicing an apple or even for self-defence. The earliest known pocket knives originated from the early Iron Age. A pocket knife with bone handle was uncovered at about 600-500 BC. Knives were predominantly worn inside sheaths or scabbards attached to a belt. Pockets in clothing is a relatively modern invention and hence before this, pockets or pouches were attached to belts, in which the early folding knives could be carried.

Most pocket knives for light duty are slipjoints, i.e. the blade does not lock, but once opened, is held in place by a spring device that allows the blade to fold if a certain amount of pressure is applied. Most slipjoint locking knives have only one blade as the locking mechanism relies on the spring along the back of the blade to lock. Slipjoints tend to be smaller in size than most typical pocket knives. Typical slipjoint knives include the Barlow, canoe, congress, elephant's toenail, peanut, penknife, sodbuster, stockman, sunfish, trapper, and whittler. Locking knives include a locking mechanism such as a twisting ring or catch that must be released in a distinct action before the knife can be folded. This locking mechanism improves safety by preventing accidental blade closure while cutting. In contrast, slipjoint knives rely only on a small sliding spring to keep the blade open, and if enough force is applied to the back of the knife, the blade will close.

Locking knives have appeared as early as the 15th century in Spain. Opinel knives incorporate a ring lock, where a ferrule rotates to lock the blade open. In the late 1800s locking pocket knives were popularized and marketed on a wider scale. Well-known locking knife manufacturers include Buck Knives, Camillus, Case, SA GE and Gerber. The most popular form, the lockback knife, was made popular by Buck Knives in the 1960's. The lockback is a refinement of the slipjoint, where the spring along the back of the knife has a hook on it and the blade has a notch. When the blade is fully open the hook and notch align, locking the blade in place. Closing the blade requires the user releasing the blade to apply pressure to the back of the blade and in addition press on a lever located on the back of the knife handle to disengage the hook from the notch and thus release the blade.

Unfortunately the known locking mechanisms may fail and a folding knife regardless of lock strength can never be as reliable as a fixed-blade knife.

Traditional folding knives are opened using nail-nicks or slots where the user's fingernail would enter to pull the blade out of the handle. This is cumbersome and requires the use of two hands. Improvements included the thumb-stud: a small stud on the blade that allows for one-handed opening, the thumb hole: where the user presses the pad of his thumb against a hole and opens the blade by rotating his thumb similarly to using the thumb-stud, the clip system: clips are usually metal or plastic and similar to the clips found on pens except thicker.

Unfortunately the known locking arrangements for folding knives are cumbersome to use, require two hands to operate, and include an expensive and complicated construction and cannot be disassembled easily for cleaning purposes.

It is an object of the invention to suggest a knife arrangement, which will assist in overcoming these problems.

SUMMARY OF INVENTION

According to the invention, a knife arrangement for folding knives, includes

(a) a handle including a first handle plate and a second handle plate, the first handle plate and the second handle plate being connected together by means of a pivot pin;

(b) a lockable folding blade pivotally mounted around the pivot pin of the handle;

(c) a slot in the folding blade adapted to receive a bush member adapted to rotate around the pivot pin;

(d) the handle and the folding blade having an upper side and a lower side; (e) biasing means, such as a spring, in the slot for urging the folding blade towards the lower side and locked position;

(f) a locking lug in the upper side of the folding blade; and

(g) at least one catch in the first handle plate or the second handle plate in the upper side of the handle for engaging the locking lug.

The knife arrangement may be a pocket knife.

The pivot pin may be formed by a bolt.

The locking lug may protrude on both sides of the folding blade.

The folding blade may include a cam at the rear of the folding blade. The knife arrangement may includes the use of a locking lug as an ambidextrous thumb-stud on the folding blade which is adapted to be operable with a finger and used for locking the folding blade in a closed position or raising the rear of the blade to unlock it into the open position.

The knife arrangement may include a first protrusion and/or recess in the lower side of the folding blade which is adapted to be operable with a finger and used for locking the folding blade in a closed position and/or open position.

The knife arrangement may include a second protrusion and/or recess in the upper side of the folding blade and/or the cam which is also adapted to be operable with a finger and used for locking the folding blade in a closed position and/or open position.

The first handle plate and the second handle plates may be connected by means of bolts and nuts and/or spacers.

The first handle plate and the second handle plates may have cut-outs in their centres.

The handle may be covered by aesthetically designed coverings including wood, bone, steel and/or other materials.

The bush member may be adapted to receive a ring member through which the pivot pin protrudes. Also according to the invention, a knife arrangement for folding knives, includes (a) a handle supporting a pivot pin;

(c) a slot in the folding blade in which the pivot pin is adapted to move;

(d) the handle and the folding blade having an upper side and a lower side;

(e) biasing means, such as a spring, in the slot for urging the folding blade towards the upper side and locked position;

(f) a locking lug in the upper side of the handle; and

(g) a catch at the rear end of the blade for engaging the locking lug. The knife arrangement may be a pocket knife.

The knife arrangement may include a first hooked finger guard on the upper side of the folding blade which is adapted to be used for locking the folding blade in a closed position.

The knife arrangement may include a second hooked finger guard on the lower side of the folding blade which is also adapted to be used for locking the folding blade in a closed position.

The folding blade may include a cam at the rear of the folding blade.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be described by way of example with reference to the accompanying schematic drawings.

In the drawings there is shown in:

Figure 1: A exploded perspective view of a knife arrangement in accordance with a first embodiment of the invention indicating the various components;

Figure 2 A perspective view of the knife arrangement shown in Figure 1 in an open and locked position;

Figure 3 A perspective view of the knife arrangement shown in Figure 1 in a closed and locked position; Figure 4: A sectional side view of the knife arrangement as shown in Figure 2;

Figure 5: A sectional side view of the knife arrangement as shown in figure 4 in a semi-open and unlocked position;

Figure 6: A sectional side view of the knife arrangement as shown in Figure 4 in a closed and locked position;

Figure 7: A side view of a knife arrangement in accordance with a second embodiment of the invention in the open and locked position;

Figure 8: A side view of the knife arrangement as shown in Figure 7 in a semi-open and unlocked position; Figure 9: A side view of the knife arrangement as shown in Figure 8 in a closed and locked position.

Figure 10: A exploded perspective view of a knife arrangement in accordance with a third embodiment of the invention indicating the various components;

Figure 11: A sectional side view of the knife arrangement as shown in Figure 10; Figure 12: A sectional side view of the knife arrangement as shown in Figure 10;

Figure 13: A sectional side view of the knife arrangement shown in Figure 10 in an open position;

Figure 14: A sectional side view of the knife arrangement shown in Figure 10 in a locked position; Figure 15: A sectional side view of the knife arrangement shown in Figure 10 in an open position;

Figure 16: A sectional side view of a knife arrangement in accordance with a fourth embodiment of the invention indicating the various components;

Figure 17: A partial exploded view of the knife arrangement as shown in Figure 16; Figure 18: A sectional side view of the knife arrangement as shown in Figure 16; Figure 19: A sectional side view of the knife arrangement shown in Figure 16 in an locked position; and

Figure 20: A side view of a knife arrangement in accordance with a fifth embodiment of the invention having two knife blades.

DETAILED DESCRIPTION OF DRAWINGS

Referring to the Figures 1 to 6, a knife arrangement in accordance with a first embodiment of the invention generally indicated by reference numeral 10 is shown.

According to the invention, a knife arrangement 10 for folding knives, includes

(a) a handle 12 including a first handle plate 14 and a second handle plate 16, the first handle plate 14 and the second handle plate 16 being connected together by means of a pivot pin 18 formed by a bolt;

(b) a lockable folding blade 20 pivotally mounted around the pivot pin 18 of the handle 12;

(c) a pivot pin slot 22 in the folding blade 20 adapted to receive a bush member 24 adapted to rotate around the pivot pin 18;

(d) the handle 12 and the folding blade 20 having an upper side and a lower side;

(e) biasing means, such as a spring 26, in the slot 22 for urging the folding blade towards the lower side and locked position;

(f) a locking lug 28 in the upper side of the folding blade 20; and

(g) a first catch 30 in the first handle plate 14 and a second catch 32 in the

handle plate 16 in the upper side of the handle 12 for engaging the locking lug

The knife arrangement 10 is generally a pocket knife.

The locking lug 28 protrudes on both sides of the folding blade 20.

The folding blade 20 includes a cam 34 at the rear of the folding blade 20. The knife arrangement includes the use of a locking lug 28 as an ambidextrous thumb-stud on the folding blade 20 which is adapted to be operable with a finger and used for locking the folding blade 20 in a closed position or raising the rear of the blade to unlock it into the open position.

The first handle plate 14 and the second handle plate 16 are connected by means of at least one bolt and nut 38 and spacer 40.

The first handle plate 14 and the second handle plate 16 have cut-outs 42 and 44 in their centres.

The bush member 24 is provided with a ring 46.

The handle 12 is adapted to be covered by aesthetically designed coverings including wood, bone, steel and/or other materials. The bush member 24 is adapted to receive a ring member 46 through which the pivot pin 18 protrudes.

The handle 12 and the folding blade 20 which is pivotally displaceable with respect to the handle 12 between a closed position as shown in Figures 3 and 6 and an open position as shown in Figures 2 and 4. The folding blade 20 pivots around the pivot pin 18 and by means of the pivot pin slot 22 in the folding blade 20 the folding blade 20 is also vertically displaceable between a locked position downward with respect to the pivot pin 18 as shown in Figures 2 and 4 and an unlocked position as shown in Figures 3, 5 and 6. The knife arrangement 10 includes a spring 26 mounted in the pivot pin slot 22 which urges the folding blade 20 to the downward locked position.

Figures 2 and 4 show the folding blade 20 in the open and locked position. The spring 26 acts to urge the locking lug 28 downward in the locked position in the first catch 30 and the second catch 32. To close the folding blade 20, force is applied to the locking lug 28 on the folding blade 20 which is adapted to be operable with a finger and used for locking the folding blade 20 in a closed position and/or open to overcome the restoring force of the spring 26 to keep folding the folding blade 20 in the locked position. The spring 26 is thereby compressed and the folding blade 20 displaced upward to unlock the knife arrangement system, the first catch 30 and the second catch 32 in the handle 12 disengaging the locking lug 28 in the folding blade 20, and releasing the folding blade 20 for rotation about the pivot pin 18 towards the closed position.

Figure 5 shows the folding blade 20 in the semi-open and unlocked position. On approaching the closed position the locking lug 28 on the folding blade 20 will continue to engage the handle 12, the locking lug 28 holding the folding blade 20 in closed position in a friction lock under bias of the spring 26 which is compressed as shown in Figure 6.

To open the folding blade 20 and withdraw it from its recess in the handle 12, the locking lug 28 in the upper side of the folding blade 20 is pushes backwards by hand to overcome the friction hold on the locking lug 28 and pushed round to rotate the folding blade 20 about the pivot pin 18. Upon reaching the position shown in Figure 5, further hand pressure upon the locking lug 28 will ensure that the folding blade 20 will co-operate with the bottom surface of the locking lug 28 so that after full rotation the folding blade 20 under bias of the expanding spring 26 will return to the locked position illustrated in Figure 4.

In this condition the folding blade 20 will remain firmly locked until deliberately unlocked again by hand in the manner described above. In compliance with the laws of physics, forces brought to bear upon the folding blade 20 vertically upwardly, except at or near the pivot pin 18, will be directed upon both the locking lug 26 and the pivot pin 18 in a direction at a right angle to such forces, so that such forces will not unlock the knife arrangement system, but will tend to lock it even tighter.

The moment the open folding blade 20 is unlocked and folded by hand, the spring 26 is at its most compressed state, and so it remains until the folding blade 20 is back and locked again in the open position, when it slightly expands. The wonder of it is that even a soft spring would work well. The vertical strength of the spring 26 has little to do with the huge horizontal locking forces produced by the system of the knife arrangement 10. The friction only has to be enough to cope with the vertical mass of the closed folding blade 20, which is negligible.

In a further embodiment, the knife arrangement may include a second protrusion and/or recess (not shown) in the upper side of the folding blade 20 and/or the cam 34 which is also adapted to be operable with a finger and used for locking the folding blade 20 in a closed position and/or open position. Furthermore the knife arrangement could include a first protrusion and recess 36 in the lower side of the folding blade 20 which is operable with a finger.

The knife arrangement 10 accordance with the invention thereby provides a locking arrangements for folding knives and pocket knives which is easily to use, requires only one hand to operate, and includes a cost-effective and simple construction which is easily disassembled and reassembled for cleaning purposes. Referring to the Figures 7 to 9, a knife arrangement in accordance with a second embodiment of the invention generally indicated by reference numeral 10 is shown.

According to the invention, a knife arrangement 10 for folding knives, includes

(a) a handle 12 supporting a pivot pin 14;

(b) a lockable folding blade 16 pivotally mounted around the pivot pin 14 of the handle 12;

(c) a pivot pin slot 18 in the folding blade 16 in which the pivot pin 14 is adapted to move;

(d) the handle 12 and the folding blade 16 having an upper side and a lower side;

(e) biasing means, in this case a spring 20, in the pivot pin slot 18 for urging the folding blade 16 towards the upper side and locked position;

(f) a locking lug 22 in the upper side of the handle 12; and

(g) a catch 24 at the rear end of the folding blade 16 for engaging the locking lug 22. The knife arrangement 10 is generally a pocket knife.

The knife arrangement 10 includes a first hooked finger guard 26 on the upper side of the folding blade 16 which is adapted to be used for locking the folding blade 16 in a closed position.

The knife arrangement 10 includes a second hooked finger guard 28 on the lower side of the folding blade 16 which is also adapted to be used for locking the folding blade 16 in a closed position.

The folding blade 16 may include a cam 30 at the rear of the folding blade 16.

The handle 12 and the folding blade 16 which is pivotally displaceable with respect to the handle 12 between a closed position as shown in Figure 3 and an open position as shown in Figure 7. The folding blade 16 pivots around the pivot pin 14 and by means of the pivot pin slot 18 in the folding blade 16 the folding blade 16 is also vertically displaceable between a locked position upward with respect to the pivot pin 12 as shown in Figure 7 and an unlocked position as shown in Figures 8 and 9. The knife arrangement 10 includes a spring 20 mounted in the pivot pin slot 18 which urges the folding blade 16 to the upward locked position. Figure 7 shows the folding blade 16 in the open and locked position. The spring 20 acts to urge the catch 24 in the blade cam 30 upwardly in the locked position behind the locking lug 22. To close the folding blade 16, force is applied to the first hooked finger guard 26 on the upper side of the folding blade 16 to overcome the restoring force of the spring 20 to keep folding the blade 16 in the locked position. The spring 20 is thereby compressed and the folding blade 16 displaced downward to unlock the knife arrangement system, the catch 24 in the folding blade 16 disengaging the locking lug 22 in the handle 12, and releasing the folding blade 16 for rotation about the pivot pin 14 towards the closed position.

Figure 8 shows the folding blade 16 in the semi-open and unlocked position. On approaching the closed position the second hooked finger guard 28 will pass through the slot in the upper side of the handle 12 to engage the locking lug 22 and hold the folding blade 16 in closed position in a friction lock under bias of the spring 20 which is slightly compressed as shown in Figure 9.

To open the folding blade 16 and withdraw it from its recess in the handle 12, the second finger guard 28 is drawn backwards by hand to unlock the friction hold on the locking lug 22 and pushed forward to rotate the folding blade 16 about the pivot pin 14. Upon reaching the position shown in Figure 8, further hand pressure upon the second finger guard 28 will ensure that the cam 30 at the back of the folding blade 16 will co-operate with the bottom surface of the locking lug 22 to compress the spring 20 in the pivot pin slot 18 so that after full rotation the folding blade 16 under bias of the expanding spring 20 will return to the locked position illustrated in Figure 7.

In this condition the folding blade 16 will remain firmly locked until deliberately unlocked again by hand in the manner described above. In compliance with the laws of physics, forces brought to bear upon the folding blade 16 vertically downward, except at or near the pivot pin 14, will be directed upon both the locking lug 22 and the pivot pin 14 in a direction at a right angle to such forces, so that such forces will not unlock the knife arrangement system, but will tend to lock it even tighter.

The knife arrangement 10 accordance with the invention thereby provides a locking arrangements for folding knives and pocket knives which is easily to use, requires only one hand to operate, and includes a cost-effective and simple construction which is easily disassembled and reassembled for cleaning purposes. Referring to the Figures 10 to 15, a knife arrangement in accordance with a third embodiment of the invention is shown.

The system is unique in that the blade is permitted to act by itself as its own locking latch. A locking lug 2 on the blade, engaging a locking notch 3 in the handle, keeps the blade firmly in the open condition against any forces which may bear down upon it from above. But any forces bearing upward against the cutting edge, will never disengage the locking lug 2 on the blade and unlock it.

These forces, by creating a moment about the pivot 1 (which is the bushing 1 inside of the square one 5, through which passes the handle bolt (5) are brought to bear against both the locking lug 2 and the pivot 1 in a direction at a right angle to such forces, so that such forces will not unlock the blade, but will tend to lock it even tighter, rendering the blade impossible to unlock. Because of the dimensional proportions in the layout, these forces are multiplied by their advantage.

The locking action of these forces increase very rapidly as pressure is applied ever closer to the tip of the blade, and the same thing happens as greater pressure is applied upon the blade by the user's hand from above. The greater the pressure upon the blade the tighter is the lock. It is a most sophisticated locking system, with so few components parts in it, but it is utterly unbreakable.

It is only when pressing upwardly against the quillon 4 beneath the pivot 1, where the torque is nil, that the blade may be unlocked from the open position, while compressing the spring 7 slightly, and folded into the handle with ease. Although under bias of the higher tension spring, the locking lug will slide without much resistance round the smooth edge of the handle cam 8 until the blade has been fully folded into the handle.

Because the dynamic forces of the locking system have not at any time any direct bearing upon the spring 7, whatever the position of the blade, a spring of surprisingly low tension may be used without any detrimental effect upon the system.

But if the friction between the locking lug 2 and the cam 8 should be insufficient to hold the blade in the closed position, a small notch there in the cam will secure the hold.

And it is due to the spring-loaded system that the locking tolerances are taken up automatically and no hand-fitting is needed in assembling the few components.

Whatever the spring tension, the easy slide of the locking lug against the slippery cam produces an amazingly slick system, with not much strain placed at any time upon the user's fingertips, the blade slipping by itself through the last ten degrees or so into the locking notch, the spring slightly expanding.

The system, which despite it being so pleasantly light and slick to operate, will nevertheless provide us with locks that are utterly unbreakable. Alternatively, due to the quality of the latest types of steel, it may be technically viable to simplify the system by doing away entirely with the square bushing 5.

Note: With the locking lug tightly wedged in the locking notch directly above the pivot, even with slightly play between the blade and the handle, the blade will not wobble.

Referring to the Figures 16 to 19, a knife arrangement in accordance with a fourth embodiment of the invention is shown.

Under the exact same system, but with the locking lug placed in the handle instead of on the blade, and the locking notch cut into the blade instead of the handle, and with a thumb-stud put on the blade as is shown here below, although very different from the third embodiment in construction, this knife has its own appeal. It is also very slick and handles brilliantly. The blade opens and closes with a satisfying click in the hand.

The system is simple, with a Spartan paucity of parts, on account of the blade acting by itself as is its own locking latch. This obviates the need for any moving parts in the empty handle. Beside the handle and blade, there are only two pins, a bushing and a spring in the knife.

A catch in the blade, engaging a locking lug in the handle, keeps the blade firmly in the open condition, against any forces which accidentally may bear down upon it from above.

But, due to the torque in the action, any forces bearing vertically upward against the cutting edge, will never disengage the catch in the blade and unlock it. These forces, by creating a moment about the pivot pin 1 (in a clockwise direction in the illustration), are brought to bear against the locking lug 2 in a direction that is horizontal, rendering the blade impossible to unlock. And because of the dimensional proportions in the layout, these forces are multiplied by their lever advantage.

The very forces taken up by the locking lug, by the same laws of physics, are also loaded down upon the pivot, although in the opposite direction, doubling their effect. The locking action of these forces, furthermore, increase very rapidly, as pressure is applied ever closer to the tip of the blade, and the same thing happens as greater pressure is placed upon the blade by the user's hand from above. The greater the pressure upon the blade, the tighter is the lock. It is a most sophisticated locking system, with almost no component parts in it, but it is utterly unbreakable.

It is only when pressing upwardly from below, against the quillon (or guard) 3 directly beneath the pivot, where the torque is nil, that the blade may be unlocked from the open position, with ease, and folded into the handle.

The blade is held in the closed position by friction against the locking lug.

Referring to the Figure 20, a knife arrangement in accordance with a fifth embodiment of the invention is shown. This knife arrangement, with the snappy opening of its blades, is the one and only twin-bladed fighting knife in the world. The variety of the blades that may be fitted to it is infinite.

Claims

PATENT CLAIMS

1. A knife arrangement for folding knives, which includes

(d) the handle and the folding blade having an upper side and a lower side;

(e) biasing means, such as a spring, in the slot for urging the folding blade towards the lower side and locked position;

(f) a locking lug in the upper side of the folding blade; and

2. A knife arrangement as claimed in claim 1, which is a pocket knife.

3. A knife arrangement as claimed in claim 1 or claim 2, in which the pivot pin is formed by a bolt.

4. A knife arrangement as claimed in any one of the preceding claims, in which the locking lug protrudes on both sides of the folding blade.

5. A knife arrangement as claimed in any one of the preceding claims, in which the folding blade includes a cam at the rear of the folding blade.

6. A knife arrangement as claimed in any one of the preceding claims, which includes the use of a locking lug as an ambidextrous thumb-stud on the folding blade which is adapted to be operable with a finger and used for locking the folding blade in a closed position or raising the rear of the blade to unlock it into the open position.

7. A knife arrangement as claimed in any one of the preceding claims, which in include a first protrusion and/or recess in the lower side of the folding blade which is adapted to be operable with a finger and used for locking the folding blade in a closed position and/or open position.

8. A knife arrangement as claimed in claim 7, which includes a second protrusion and/or recess in the upper side of the folding blade and/or the cam which is also adapted to be operable with a finger and used for locking the folding blade in a closed position and/or open position.

9. A knife arrangement as claimed in any one of the preceding claims, in which the first handle plate and the second handle plates are connected by means of bolts and nuts and/or spacers.

10. A knife arrangement as claimed in any one of the preceding claims, in which the first handle plate and the second handle plates have cut-outs in their centres.

11. A knife arrangement as claimed in any one of the preceding claims, in which the handle is covered by aesthetically designed coverings including wood, bone, steel and/or other materials.

12. A knife arrangement as claimed in any one of the preceding claims, which includes a bush member adapted to receive a ring member through which the pivot pin protrudes.

13. A knife arrangement for folding knives, which includes

(a) a handle supporting a pivot pin;

(c) a slot in the folding blade in which the pivot pin is adapted to move;

(d) the handle and the folding blade having an upper side and a lower side;

(f) a locking lug in the upper side of the handle; and

(g) a catch at the rear end of the blade for engaging the locking lug.

14. A knife arrangement as claimed in claim 13, which is a pocket knife.

15. A knife arrangement as claimed in claim 13 or claim 14, which includes a first hooked finger guard on the upper side of the folding blade which is adapted to be used for locking the folding blade in a closed position.

16. A knife arrangement as claimed in any one of claims 13 to 15, which includes a second hooked finger guard on the lower side of the folding blade which is also adapted to be used for locking the folding blade in a closed position.

17. A knife arrangement as claimed in any one of claims 13 to 16, in which the folding blade includes a cam at the rear of the folding blade.

18. A knife arrangement substantially as hereinbefore described with reference to the accompanying drawings.