ZA200808538B

ZA200808538B - Cutting implement

Info

Publication number: ZA200808538B
Application number: ZA200808538A
Authority: ZA
Inventors: Niekerk Cornelius Benjamin Cronje Van
Original assignee: Niekerk Cornelius Benjamin Cronje Van; Kusel Aletta Fredrika
Priority date: 2007-07-25
Filing date: 2008-10-07
Publication date: 2010-01-27

Description

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THIS INVENTION relates to a cutting implement. It also relates to a method of modifying a cutting implement.

Conventional cutting implements such as utility knives, or the like usually comprise a hollow handle or body and a blade, part of which is housed in the cavity. In use, a portion of the blade on which a cutting edge is provided is exposed thereby to enable the knife to be used to cut through material.

The Inventor has noticed that during use, and also during periods of non-use, the exposed portion of the blade or more particularly the cutting edge thereof can cause injuries to those who come into contact therewith.

According to one aspect of the invention there is provided a cutting implement which includes an elongate hollow body defining an internal cavity; a blade, part of which is housed in the cavity and which protrudes from an end of the body, the blade having a longitudinally extending cutting edge; and a guard part of which is positioned in the cavity and which is displaceable ,

Co between-an extended position towards which it is resiliently biased and in which it covers at least a major portion of the cutting edge of the blade, and a retracted position in which at least part of the cutting edge of the blade is exposed.

The guard may be slidably mounted on the body and at least part of the guard may be retracted into the cavity when it is displaced from its extended position to its retracted position.

The guard may include, at or towards a free end thereof, an abutment formation configured, on abutment with an article to be cut, to displace the guard towards its retracted position and permit the cutting edge of a blade to come into contact with the article.

The guard may include a generally planar body which extends generally parallel to the blade and a transverse lip which protrudes from the body and which, in the extended position of the guard covers the cutting edge of the blade.

The cutting implement may include resilient biassing means configured resiliently to urge the guard towards its extended position.

The resilient biassing means may be in the form of a spring mounted in ‘compression between the guard and the housing.

The blade may be fixedly attached in position.

Instead, the blade is longitudinally displaceable relative to the housing to permit retraction of the blade into the housing.

According to another aspect of the invention there is provided .a method of modifying a cutting implement of the type which includes an elongate hollow body defining an internal cavity and an elongate blade, part of which is located in the cavity, the blade protruding from the cavity and having a cutting edge on at least 725 part of a'longitudinally extending edge of at least part of the protruding partofthe blade, the method including the step of mounting a guard to the body such that part of the guard is positioned in the cavity and the guard is slidably displaceable between an extended position towards which it is biased in which it covers the cutting edge of the blade and a retracted position in which the cutting edge of the blade is exposed.

In its extended position a portion of the guard may be positioned in the cavity and the remainder of the guard protrudes therefrom and covers the cutting edge and in its retracted position the guard may be displaced inwardly into the cavity to expose the at least part of the cutting edge. 5 .

The method may include mounting a spring between the guard and the body, the spring being configured to urge the guard resiliently towards its extended position.

In use, it will be understood that the abutment formation may abut an object to be cut and on application of a force thereto, the guard is retracted towards its retracted position thereby to expose the cutting edge of the blade and to further compress the compressed spring. It will be further understood that as soon as the force is removed, the guard is resiliently displaced under action of the compressed spring to its rest position. :

The invention will now be further described, by way of example, with reference to the accompanying diagrammatic drawings. fn the drawings:

Figure 1 shows a sectional side view of a cutting implement in accordance with the invention wherein the guard is in the rest or extended position;

Figure 2 shows a sectional side view of the cutting implement of Figure 1 wherein the guard has been displaced towards its retracted position; and

CC TT38TT TTT Figure 3 ‘shows an end view of the cutting implement of Figures and 2.

In the drawings a cutting implement in the form of a utility knife or : carton cutter in accordance with the invention is generally indicated by reference numeral 10. The knife 10 includes an elongate hollow housing 12 defining a cavity 13.

The housing 12 defines an open end or mouth 12.1 which leads from an end of the cavity 13. A blade 16 is mounted to the housing 12 such that a portion of the blade is located in the cavity 13 and an end portion thereof protrudes from the housing 12. In other example embodiments, the blade 16 may be longitudinally displaceable within the housing 12 between a retracted position and one or more extended positions in which it is releasably lockable.

An edge of the blade opposite a cutting edge 16.1 may be sandwiched between adjacent parts of the housing to support the blade. It will be appreciated that the outer surface of the housing 12 may vary, e.g. it could be curved.

The knife 10 further includes a guard 14 which is displaceable between an extended position (shown in Figure 1) in which it covers the cutting edge 16.1 and a retracted position (shown in Figure 2) in which it is retracted into the cavity 13 to expose the cutting edge 16.1

As can best be seen in Figure 3 of the drawings, the guard 14 is generally L-shaped and comprises a major wall 14.1 which abuts or is closely ‘adjacent to a major face of the blade 16 and a transverse lip 14.2 (Figure 3) which is adjacent to and, when the guard is in its extended position, covers the cutting edge 16.1 of the blade 16 to prevent inadvertent contact with the cutting edge 16.1. The guard 14 is secured to the housing by way of a bolt or screw 22 which extends through a longitudinally extending slot 14.3 provided in the major wall 14.1 thereof to permit limited longitudinal displacement of the guard 14 relative to the screw 22, and therefore the housing 12. Resilient bias means in the form of a coil spring 18 is mounted in compression between complementary mounting formations 21, 23 provided respectively on the end of the guard 14 positioned in the cavity 13 and the end 12.2 of the housing 12 remote from the mouth 12.1. The spring 18 urges the guard 14 out of the housing towards its extended position, shown in Figure 1 of the drawings. If desired a sleeve or cover 19 may be positioned around the spring as shown in broken lines in

Figures 1 and 2.

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The guard 14 also includes an abutment formation 14.4 which protrudes therefrom. In this particular example embodiment, the abutment formation 14.4 is provided on the guard 14 adjacent the free end thereof. In this example embodiment, the abutment formation 14.4 includes an L-shaped member 30 (shown in Figure 3) which is secured to the major wall 14.1 by a stud 32.

It will be noted that the guard may be typically constructed of a synthetic plastics material.

It will be appreciated that the knife 10 can be constructed ab initio to incorporate the guard 14. Instead, an existing utility or craft knife (such as that available under the trademark Stanley) may be modified to incorporate a : 15 guard 14 part of which is located in the same cavity as the blade 16 and which is longitudinally displaceable between an extended position, towards which it is resiliently biased, and a retracted position in the manner described above.

In use, referring to Figures 1 to 3, when it is desired that an article 40, as shown in Figure 2, is to be cut with the knife 10, the knife 10 is positioned adjacent the article 40 such that the abutment formation 14.4 of the guard 14 abuts the article 40 (which is shown to be a cardboard box). A force is then applied to the knife in the direction of arrow 20 (usually by a human operator thereof). The force applied to the knife 10, in particular to the abutment formation 14.4 of the guard 14 causes the guard 14 to retract in the direction of arrow 30 (Figure 2) into the cavity 13 of the housing 12 against the action of the spring 18 thereby exposing the cutting edge 16.1 of the blade 16 (shown in Figure 2). The cutting edge 16.1 may be used to cut the article 40 whilst the guard is in the retracted position.

It will be understood that the retraction of the guard 14 further compresses the compressed spring 18. In this regard, it will be appreciated that once the force in the direction of arrow 20 is removed for example when the operator ceases cutting the article 40, or if the knife slips during cutting, the guard 14 is automatically urged in the direction of arrow 20 under action of the compressed spring 18 to the rest position as shown in Figure 1 thereby at least partially covering the blade 16.

The Inventor believes that the invention as hereinbefore described provides a safer way of cutting articles in that the blade of the knife is covered in the event of the blade slipping during cutting or non-use. The invention also removes the need to cover the blade of a knife once done cutting as the guard automatically covers the blade when in non-use.

Claims

1] E— or SR CLAIMS

1. A cutting implement which includes an elongate hollow body defining an internal cavity; a blade, part of which is housed in the cavity and which protrudes from an end of the body, the blade having a longitudinally extending cutting edge; and a guard part of which is positioned in the cavity and which is displaceable between an extended position towards which it is resiliently biased and in which it covers at least a major portion of the cutting edge of the blade, and a retracted position in which at least part of the cutting edge of the blade is exposed.

2. A cutting implement as claimed in claim 1 in which the guard is slidably mounted on the body and at least part of the guard is retracted into the cavity when it is displaced from its extended position to its retracted position.

3. A cutting implement as claimed in claim 2, in which the guard includes, at or towards a free end thereof, an abutment formation configured, on abutment with an article to be cut, to displace the guard towards its retracted position and permit the cutting edge of a blade to come into contact with the article.

4. A cutting implement as claimed in claim 2 or claim 3, in which the guard : includes a generally planar body which extends generally parallel to the blade and a transverse lip which protrudes from the body and which, in the extended position of the guard covers the cutting edge of the blade.

5. A cutting implement as claimed in claim 4, which includes resilient biassing means configured resiliently to urge the guard towards its extended position.

6. A cutting implement as claimed in claim 5, in which the resilient biassing means is in the form of a spring mounted in compression between the guard and the housing.

7. A cutting implement as claimed in any one of the preceding claims, in which the blade is fixedly attached in position.

8. A cutting implement as claimed in any one of claims 1 to 6, inclusive, in which the blade is longitudinally displaceable relative to the housing to permit retraction of the blade into the housing.

9. A method of modifying a cutting implement of the type which includes an elongate hollow body defining an internal cavity and an elongate blade, part of which is located in the cavity, the blade protruding from the cavity and having a cutting edge on at least part of a longitudinally extending edge of at least part of the protruding part of the blade, the method including the step of mounting a guard to the body such that part of the guard is positioned in the cavity and the guard is slidably displaceable between an extended position towards which it is biased in which it covers the cutting edge of the blade and a retracted position in which the cutting edge of the blade is exposed.

10. A method as claimed in claim 9, in which its extended position a portion of the guard is positioned in the cavity and the remainder of the guard protrudes therefrom and covers the cutting edge and in its retracted position the guard is displaced inwardly into the cavity to expose the at least part of the cutting edge.

11. A method as claimed in claim 10, which includes mounting a spring between the guard and the body, the spring being configured to urge the guard resiliently towards its extended position. :

12. A cutting implement as claimed in claim 1 substantially as described and illustrated herein with reference to the drawings.

13. A method as claimed in claim 9 substantially as described and illustrated herein with reference to the drawings. DATED THIS 7" DAY OF OCTOBER 2008 C ADAMS &A : APPLICANTS PATENT ATTORNEYS