GB2309190A - Knife with built-in light - Google Patents

Description

Title. IMPROVEMENTS IN OR RELATING TO KNIVES This invention relates to knives and seeks to provide an improvement over existing knives.

A problem frequently encountered by divers, for example, is the use of a knife in poor visibility conditions under water to cut lines or other underwater obstructions and entanglements. In such conditions of poor visibility, a light is required in order to illuminate an area in which cutting by means of a knife is required. It is therefore necessary for a diver to hold a light in one hand and to cut the line, net or other article with the knife in his other hand. In the case of a strong current, however, it is frequently necessary for a diver to hang onto a fixed object with one hand, while effecting cutting operations with a knife in his other hand, in order not to be swept away by the current. In this case, it is not possible to illuminate the cutting area because the diver does not have a free hand.

One attempt at solving this problem is to mount a lantern on a diver's head but this arrangement is not entirely satisfactory. In the first place, the fixed object to which the diver must hang onto and the area to be cut may be so far apart that the diver can only reach the cutting area with outstretched arms. In that case, the diver's head will be some distance from the cutting area and if there is a lot of sediment in the water, so much light from the lantern on the diver's head will be absorbed by the sediment that very little effective illumination will reach the cutting area. Further, some of the light will be reflected back by the sediment and since the lantern will normally be located on the diver's forehead, most of the reflected light will come back to the diver's eyes thereby impairing vision of the cutting area.

Secondly, even if the cutting area is closer to the fixed object such that a diver can reach both without outstretched arms, it frequently occurs that there is an underwater obstruction between the diver's head and the cutting area which throws a shadow onto the cutting area and makes vision of said area difficult if not impossible.

The present invention aims to overcome the above-mentioned disadvantages.

According to the invention, there is provided a knife comprising a blade and a handle, wherein the handle is provided, at one end which is adjacent to the blade, with a transparent window on each side of the blade, wherein the handle is further adapted to hold at least one lamp bulb and one or more batteries for lighting the lamp bulb(s) and wherein switch means are provided for switching the lamp bulb(s) on or off.

Preferably, the knife blade extends into the handle and a respective lamp bulb is located on each side of the blade portion within the handle, each bulb being associated with a respective transparent window at said one end of the handle.

Each transparent window preferably takes the form of a lens.

The other end of the handle is desirably provided with a detachable end cap by means of which the battery or batteries and/or the lamp bulb or lamp bulbs can be replaced. The end cap may be provided with a female screw-thread which is adapted to engage with a corresponding male screw-thread provided on the said other end of the handle. Alteratively, the end cap may be engaged on the said other end of the handle by means of a bayonet-type connection or it may simply be a push fit on the handle.

According to one embodiment of the invention, the end cap is adapted to be fitted to the handle in a watertight manner so that the lamp bulb(s) and battery or batteries are sealed from water when the knife is submerged. A seal, such as a O ring, will normally be provided between the end cap and the said other end of the handle. The connection between the blade and the handle should also be watertight to prevent water from entering the handle.

In this case, the switch means may comprise an electrical contact on the inside of the end cap which is arranged to complete an electric circuit to light the lamp bulb(s) when the end cap is screwed further onto the handle in the case of a threaded connection, is turned relative to the handle in the case of a bayonet-type connection or is pushed towards the blade in the case of a push fit. Alternatively, a water-sealed switch may be located at a convenient position on either the end cap or the handle.

According to another embodiment of the invention, the handle is adapted to contain at least two waterproof torches of the "PEN-LITE" type. In this case it is not essential for the connection between the end cap and the handle nor the connection between the blade and the handle to be watertight. In this embodiment, the handle is preferably made of a squeezable material whereby, on being squeezed, torches located inside the handle are acted on by the pressure of the squeezing action and switches provided on the torches are activated to switch on the torches.

Since squeezable material is relatively soft, a portion of the blade desirably extends through the handle to the end cap, to which it is secured, in order to impart rigidity to the handle. The said handle is desirably moulded during manufacture with chambers for receiving the torches and the chambers are so arranged to locate the torches in such a position that switches fitted thereon may be readily engaged to switch on the associated torches when the handle is squeezed. Although a single torch may be provided on each side of the blade portion in the handle it is preferred to provide two torches on each side of the blade portion in the handle. This arrangement not only increases the illumination but also reduces the risk of failure since if one torch should fail, illumination will still be provided by the other torch on each side of the knife.

The invention will now be further described, by way of example, with reference to the drawings, in which: Fig. 1 is a perspective view of one embodiment of a knife according to the invention; Fig. 2 is a view of the blade end of the knife shown in Fig. 1; and Fig. 3 is a view of the handle end of the knife shown in Fig. 1.

Referring to the drawings, a knife according to the invention comprises a blade 1 which extends into a handle 2, a guard 3 being provided at the end of the handle from which the blade extends. The guard 3 is provided with a pair of apertures in each of which is located a respective transparent lens 4. As shown in Figs. 1 and 2 of the drawings, each lens 4 takes the form of a truncated semicircle with its chord extending substantially parallel to the plane of the blade 1.

The handle 2 is hollow and a portion of the blade (not shown) extends through the handle and may be secured to an end cap 5. The end of the blade may be provided with a screw-thread and the end cap may be provided with a corresponding screw-thread for this purpose. Alternatively, the handle may be moulded onto the blade and the end cap 5 secured to the end of the handle which is remote from the guard 3.

As shown in Fig. 3, the handle is adapted to contain four small torches 6, preferably of the zPEN-Ls type. The handle is made of squeezable material and switches (not shown) on the torches 6 are so arranged that, when the handle is squeezed, the switches are actuated to light the torches. The light from the torches will issue from the handle 2 through the lenses 4 and will thus provide illumination on each side of the blade 1.

As stated above, the knife according to the invention is primarily intended for use by divers so that the torches should be waterproof. Alternatively, or in addition, the end cap 5 may be provided with a seal (not shown) whereby the interior of the handle is rendered watertight, as above described, when the end cap is fitted to the handle.

It will be seen that, by means of a knife according to the invention, a diver has a ready and convenient means of illuminating an area in which cutting is needed and that the illumination will be effective even if the diver has only one free hand.

The invention is not restricted to the above-described embodiment but variations and modifications may be made without departing from the scope thereof.

Further, although the knife according to the invention is primarily intended for use by divers, it is not restricted to such use but is capable of use by other persons, such as firemen, who have to perform cutting operations under conditions of poor visibility such as, for example, smoke-filled rooms.

Claims (20)

1. A knife comprising a blade and a handle, wherein the handle is provided, at one end which is adjacent to the blade, with a transparent window on at least one side of the blade, wherein the handle is further adapted to hold at least one lamp bulb and one or more batteries for lighting the lamp bulb(s) and wherein switch means are provided for switching the lamp bulb(s) on and off.

2. A knife according to claim 1, wherein the handle is provided with a transparent window on each side of the blade.

3. A knife according to claim 2, wherein the knife blade extends into the handle and a respective lamp bulb is located on each side of the blade portion within the handle, each bulb being associated with a respective transparent window at said one end of the handle.

4. A knife according to any one of the preceding claims, wherein the or each transparent window takes the form of a lens.

5. A knife according to claim 4, wherein the or each lens is mounted in a guard for the handle which is located between the handle and the blade.

6. A knife according to any one of the preceding claims, wherein the other end of the handle is provided with a detachable end cap by means of which the battery or batteries and/or the lamp bulb or lamp bulbs can be replaced.

7. A knife according to claim 6, wherein the end cap is provided with a female screw-thread which is adapted to engage with a corresponding male screwthread provided on the said other end of the handle.

8. A knife according to claim 6, wherein the end cap is engageable on the said other end of the handle by means of a bayonet-type connection.

9. A knife according to claim 6, wherein the end cap is a push fit on the said other end of the handle.

10. A knife according to any one of claims 6 to 9, wherein the end cap is adapted to be fitted to the handle in a watertight or at least water-resistant manner.

11. A knife according to claim 10, wherein a seal is provided between the end cap and the said other end of the handle.

12. A knife according to claim 10 or claim 11, wherein the connection between the blade and the handle is watertight or at least water resistant.

13. A knife according to any one of claims 10 to 12, wherein the switch means comprise an electrical contact on the inside of the end cap which is arranged to complete an electric circuit to light the lamp bulb(s) when the end cap is moved towards the handle.

14. A knife according to any one of claims 10 to 12, wherein the switch means comprise a water-sealed switch located at a convenient position on the end cap or on the handle.

15. A knife according to any one of claims 6 to 9, wherein the handle is adapted to contain at least one waterproof torch.

16. A knife according to claim 15, wherein the handle is made of squeezable material and the or each torch is so arranged within the handle that squeezing of the handle is effective to exert pressure on the torch or torches to switch on said torch or torches.

17. A knife according to claim 16, wherein a portion of the blade extends through the handle to the end cap to which it is secured.

18. A knife according to any one of claims 15 to 17, wherein the handle is provided with a plurality of chambers and wherein each chamber is adapted to receive a respective torch.

19. A knife according to claim 18, wherein the handle is provided with four chambers, two chambers being located on each side of the blade.

20. A knife substantially as described herein with reference to the drawings.