[0001] The present invention relates to a knife, particularly suitable for skin-diving activities,
but usable as well for other activities.
[0002] Conventional knives for skin-divers comprise, in a thoroughly traditional fashion,
two separate members, i.e. a sheath, made usually of plastics material, provided with
means for connection to a part of a skin-diver's equipment, and a knife comprising
a steel blade and a handle, usually of plastics material, secured to the tang of the
blade.
[0003] The object to the present invention is to provide a knife, particularly suitable
for skin-diving activities, comprising only two members, i.e. a blade provided with
an integral extension forming a tang having substantially the same length as the blade,
and a tubular member inserted over said tang and said blade in such a manner as to
be slidable from a first position wherein it covers the blade and acts as a sheath,
to a second position wherein it covers said tang and acts as a handle for the blade
which is then uncovered. Both the blade and the tubular member are provided with co-operating
releasable locking means for firmly holding said tubular member in both said first
and second positions. Finally, the knife is equipped with means for connection in
a quick-releasable manner to an element of a skin-diver's equipment as, for example,
to his ballast-belt or harness.
[0004] Further objects and advantages of the knife according to the invention will become
apparent from the following detailed description of a preferred embodiment thereof,
shown as non-limiting example in the accompanying drawings, wherein:
Figure 1 is a partly sectional view of the knife according to the invention, with
the parts shown in the position in which the tubular member has been slid onto the
tang to serve as a handle, thus exposing the blade;
Figure 2 is a view similar to Figure 1, with the parts shown in the position in which
the tubular member has been slid onto the blade to serve as a sheath;
Figure 3 is a perspective view of the releasable locking means for the slidable tubular
member; and
Figure 4 is a perspective view of a device for connecting the knife according to the
invention to a belt or the like.
[0005] With reference to the drawings and more particularly to Figures 1 to 3 thereof, numeral
1 denotes the blade of the knife. Said blade 1 is provided with a tang 2 in the form
of an integral extension having at least the same length as the blade 1. Said tang
2 is, in turn, provided at the free end thereof with a ring-shaped extension 3 for
the purposes which will be described later.
[0006] Slidably inserted on the assembly blade 1-tang 2 is a tubular member 4. The tubular
member 4, which is made, preferably, of plastics material, is formed with a tubular
passage 104 having a cross sectional shape which is substantially complementary to
the cross sectional shape of the tang 2, and provided in proximity of the two ends
of the tubular passage 104 with two slots 204, 304. The blade 1 is provided with a
notch 102 at the region merging with the tang 2. Moreover, the blade 1 is provided
at said region with a locking member 5 comprising, as best shown in Figure 3, a bracket-like
portion 501 comprising a through-hole 502 which co-operates with a pin 103 passed
through the blade 1. Connected to the bracket portion 501 is a resilient tongue 503
provided at one end thereof with a detent 504. Said detent 504 can fit into the slots
204, 304 of the tubular member 4, and it may be released from said slots by depressing
its end inwards in the direction of the arrow P of Figure 1 or 2, so as to force it
partly into the notch 102.
[0007] The operation of the knife described above will be now apparent.
[0008] Assuming that the knife is in the position of Figure 2, i.e. with the tubular member
4 disposed on the blade to serve as a sheath, in this position the detent 504 will
protrude through the slot 304. In order to expose the blade, a force is exerted in
the direction of the arrow P against the end of the detent 504 protruding from the
slot 304, pushing it into the notch 102 and, thus, releasing the tubular member 4
from the blade 1. By holding the tubular member 4 stationary and by simultaneously
exerting an axial thrust on the tang 2, the blade is projected outwards until it reaches
the position shown in Figure 1, wherein the detent 504 snaps into the slot 204. In
this position, the tubular member 4 will be positioned on the tang 2 to serve as a
handle for the knife. In order to return to the rest position shown in Figure 2, the
reverse operations shall be carried out.
[0009] The annular extension 3 of the tang 2 is intended for fastening with a member 6 to
be connected to the skin-diver's harness. Said member 6 may be, for example, in the
form of a resilient hook-like member 601 to tbe inserted into a complementary member
worn by the skin-diver, or it may be in the form of a "velcro" fastening device, or
any other suitable device. A simple and particularly suitable device is shown in Figure
4.
[0010] With reference to Figure 4, the tubular member 4 comprises, in the two larger outer
faces thereof, two grooves 401,402 extending longitudinally over the entire length
thereof. The tang 2 comprises a fork-like extension 201 parallel thereto, the free
end of which may be inserted into either one of the two grooves of the tubular member
4, for example, in the illustrated case, the groove 401.
[0011] In the rest position of the knife, i.e. in the position of Figure 2 wherein the tubular
member 4 serves as a sheath for the blade, the fork-like extension 201 may be easily
inserted, due to its resiliency, over a belt 7 forming a part of the skin-diver's
equipment, so as to hold the knife. Said extension may be disengaged from the belt
7 as easily, and the knife may be turned into its operative condition by sliding the
tang 2 into the tubular member 4 and by simultaneously sliding the extension 201 into
the groove 401.
1. A knife for skin-diving activities, characterized by the fact that it comprises
a blade (1), a tang (2) extending from said blade (1), and a tubular member (4) inserted
over said tang (2) and adapted to be slid from a first position wherein it covers
said blade (1), to a second position wherein it covers said tang (2) and exposes the
blade (1).
2. A knife according to claim 1, characterized by the fact that said tang (2) is of
a length which is equal or slightly longer than that of the blade (1).
3. A knife according to claim 1, characterized by the fact that either said blade
(2) or a member (5) associated with said blade, and said tubular member (4) are provided
with co-operating releasable locking means (204, 304, 504) to firmly hold said tubular
member (4) in said first and second positions.
4. A knife according to claim 1, characterized by the fact that it further comprises
means (6, 201) for connection in a quick-releasable manner to a piece of the skin-diver's
equipment, for example, his belt, harness, vest, suit, or the like.
5. A knife according to claim 3, characterized by the fact that said locking means
comprises two radial slots (304, 204) at the ends of said tubular member (4), and
a detent member (504) secured to a resilient tongue (503) which is fixed to said blade
(1), and adapted to fit into said radial slots (204, 304).
6. A knife according to claim 4, characterized by the fact that said connecting means
comprises a resilient tongue (201) of a length slightly longer than said blade portion
(1), secured at one end thereof to the end of said tang (2) and extending parallel
to said tang (2) into a groove formed in said tubular member (4).