GB2174947A - Folding knife - Google Patents

Abstract

A folding knife has a blade 1 pivoting in the handle 2 so that the blade folds sideways into the handle. The handle is a single, rigid component and the pivot means are anchored in it. Means are provided to hold the blade in the open and closed positions, and to control the movement of the blade, so that it cannot open by the force of gravity or by centrifugal force. These means may consist of a spring (3, Figure 1) biased against the tang 5 of the blade 1 or some part thereof to hold the blade in its closed position and to control its movement. Further means, to lock the blade in the open position, consist of a spring 6 extending along the top and over the front of the handle, and shaped so as to form a catch in which the top edge of the blade engages. <IMAGE>

Description

SPECIFICATION Afolding knife This invention relatestoafolding knife.

Folding knives are in common use. Such knives typically have a blade pivoting in the handle at right angles to the plane of the blade, so that it folds into a slot in the handle. A length of stiff steel acting as a spring is biased against the tang of the blade. The tang is shaped so that the spring holds the blade in the open and closed positions, and controls the movement of the blade so that it cannot open by the force of gravity or by centrifugal force.The tang of the blade is also shaped so that a cut out section butts against the end of the spring when the blade is fully open, andthe blade isthus keptfrom turningfurther, However this design necessitates a particularly robust and heavy handle, to take the stresses imposed by the stiffness ofthe spring and by the leverage ofthe blade, when in use, against the end of the sping. Further, this design means that the length of the cutting part ofthe blade must be considerably less than halfthetotal length of the knife when the blade is in the open position, Furthermore, such knives are difficult to open with the fingers of one hand, commonly requiring the user to hold the knife in one hand and open it with the other, either by applying his thumbnail to a slitinthe blade, or by gripping the back of the blade between finger and thumb.

In the United Kingdom, the Restriction of Offensive Weapons Act 1959, as amended, prohibits (among other activities) the manufacture, sale, hire or importation of any knife which opens automatically (sometimes known as a "flick knife"); and also of "any knife which has a blade which is released from the handle or sheath thereof by the force of gravity or the application of centrifugal force and which, when released, is locked in place by means of a button, spring, lever, or other device, sometimes known as a 'gravity knife' ".The phrase "is released" has been interrupted in law as meaning "is capable of being released" (seeM. PotterLtd. v. Customs and Excise Commissioners [1973] Crim. L. R. 116). Hence the method of construction referred to above.

Some ofthe disadvantages of those knives in common use can be overcome if a folding knife is constructed so that the blade pivots in the handle in the plane of the blade, and thus folds sideways into the handle, which is shaped so asto accomodateit.

One such knife is described in United Kingdom Patent Specification 1 567127. Here the tang ofthe blade pivots between the inwardly-biased arms of a U-shaped handle. The tang and one or both arms of the handle have interfitting concave/convex shapes.

The blade is thus held in the open and closed positions by the biassing of the arms of the handle.

However such a knife lacks means of locking the blade securely in the open position, with the obvious disadvantage that the blade may accidentally pivot sideways in use and mayinjuretheuserordamage the materials upon which he is working. Furthermore, if the arms ofthe handle are biased strongly enough to hold the blade firmly in the open position, so also will they hold it firmly closed, and it will be difficult or impossibleto open with the fingers of one hand.

Another such knife is described in European Patent Specification 0 077 068. Here, similarly, the tang ofthe blade pivots between the inwardly-biased arms of a U-shaped handle. Howeverthe tang locates in a rectangular groove in the handle, so that the blade can be locked securely in the open or closed position, and means are provided so that the user, holding the knife in one hand, can movethearmstothehandle apart.

However such a knife lacks means for controlling the movement ofthe blade, which, once the arms of the handle are moved apart, is thus free to open by the force of gravity or by centrifugal force. Since means are provided to lockthe blade in the open position, such a knife would come within the Restriction of Offensive Weapons Act 1959, with the consequences described above. Furthermore,the need to move the arms of the handle apart leads to a clumsy method of opening, limits the possibie methods of construction, and weakens the knife.

There also remains the riskthatthe user, in cutting with the knife, may accidentally operate the means for moving the arms ofthe handle apart, sothatthe blade is free to pivot sideways.

According to the present invention there is provided a folding knife with a blade pivoting in the handle in the plane ofthe blade, so that it folds sideways into the handle, means being provided to control the movement of the blade, so that it cannot be opened bythe force of gravity or by centrifugal force, and means being provided to lockthe blade in the open position.

Means may also be provided to lockthe blade in the closed position.

A specific embodiment of the invention will now be described byway of example, with reference to the accompanying drawing in which: Figure 1 shows the view of one side, with the blade in the closed position; Figure2 shows the view of the other side, with the blade in the open position; Figure 3 shows a perspective view of the spring and thumbpiece fitted to the top of the knife.

Referring to the drawing, the blade 1 pivots in the handle 2 by pivot pins or other means not shown. The handle 2 has a recess shaped to accomodate the blade 1. Both pivot pins are anchored in the handle. A spring 3, fixed at its rearward end to the handle 2 by means not shown, and acting through an opening 4 in the handle, is biased against a projection 5 on the tang of the blade. Afurtherspring 6 is fixed at its rearward end to the handle 2 by means not shown, and extends overthe front ofthe handle and downwards, where its forward end is shaped so as to form a catch. The handle has a further opening 8.

The blade is held in the closed position by the biasing ofthe spring 3 against the projection Son the tang ofthe blade. To open the knife, the user presses the blade out of the handle with the tips of hisfingers through the opening 8 in the handle.

The movement of the blade is controlled by the biasing of the spring 3, and also by friction between the pivot pins and the handle caused by the biasing of the spring 3, so thatthe blade cannot open by force of gravity or by centrifugal force.

As the blade reaches the fully open position the forward part ofthe spring 6 is pushed upwards bythe blade and then returns to itsformer position, so that the blade is located in the catch on the spring 6 and is thus locked in position. The spring 6 has a thumb-piece 7 shaped so that it can be used to pull up the forward part ofthe spring 6 and so release the blade.

Claims (6)

1. Afolding knife with a blade pivoting in the handle in the plane ofthe blade, so that it folds sideways into the handle, means being provided to control the movement of the blade so that it cannot open by force of gravity or by centrifugal force, and means also being provided to lock the blade in the open position.

2. Afolding knife as claimed in claim 1 ,wherein means are also provided to lock the blade in the closed position.

3. Afolding knife as claimed in claims 1 or2, wherein the means provided to control the movementofthe blade consists of a spring biased against the tang of the blade or some partthereof.

4. Afolding knife as claimed in any preceding claim wherein the means provided to control the movement ofthe blade and the means provided to lockthe blade in the open and/or closed positions consist ofthe same orsubstantiallythe same component.

5. Afoiding knife as claimed in any preceding claim, wherein the handle consists of a single, rigid component, in which the blade is anchored by both pivot pins.

6. Afolding knife as claimed in any preceding claim, wherein the handle consists of a single component in which the blade is anchored by both pivot pins.

6. Afolding knife substantially as described herein with reference to the accompanying drawing.

Amendments to the claims have been filed, and havethefollowing effect: (a) Claim 5 above has been deieted ortextually amended.

(b) New ortextually amended claims have been filed asfollows: (c) Claims 3 and 6 above have been renumbered as 5 and 7 and their appendancies corrected.

3. Afolding knife as claimed in claims 1 or2, wherein a thumbpiece is associated with the means provided to lockthe blade in the open position.