BACKGROUND OF THE INVENTION

[0001 ] The invention relates to a lifting member for lifting projectiles, and for the lifting purpose the lifting member is provided with a fastening member whereto a lifting hook or the like is to be fastened; a body part to which the fastening member is fastened; and a threaded part provided with threads corresponding to threads in a primer opening at an end of a projectile for installing the lifting member to the primer opening of the projectile for lifting the projectile.

[0002] Projectiles and shells of field artillery in particular are handled and stored in great numbers. In order to be moved, a shell is typically provided with a lifting member, i.e. a lifting loop, screwed to the threads provided for a primer at an end of the projectile and having a loop for fastening a hook or a similar fastening member thereto. Prior art lifting loops are ordinary metal pieces with a lifting ring at one end and a threading at the other. This is, however, a significant risk factor in the event of fire or other accidents, because the explosive inside a closed projectile tends to explode easily upon heating, whereby the projectile splinters and causes danger and material damages.

[0003] US Patent 3665857 discloses a solution in which a lifting loop provided with one or more openings closed with a material that melts at a temperature significantly lower than that of the steel material of the actual lifting loop. The aim is that as temperature increases, the metal that closes the opening melts, both releasing the pressure caused by the temperature rise and allowing the explosive in the projectile to flow out as it expands by impact of the temperature.

[0004] A problem with the solution of the US patent is that in order it to work, the projectile and the lifting loop in particular must heat up. Moreover, a significant temperature rise causes a significantly increased risk of the explosive in the projectile to ignite. A further problem of the solution in question is that to ensure the resistance and operation of the lifting loop, the opening has to be relatively small, which complicates and impairs its performance.

BRIEF DISCLOSURE OF THE INVENTION

[0005] An object of the invention is to provide a lifting member which functions more reliably and provides a significantly larger opening from the inner projectile space into the open air. [0006] The lifting member of the invention is characterized in that the body part is provided with a locking bush extending into the opening in the projectile when the lifting member is installed in the projectile and having through-holes in the transverse direction thereof;

that the threaded part is a separate part installed outside the locking bush and has a threading on the outer surface thereof and at least one locking recess on the inner surface thereof;

that the lifting member is further provided with

at least one separate locking part, which extends through an opening in the locking bush and into the locking recess in the threaded portion and in that position locks the locking bush and the threaded portion together at least in their axial direction;

a stopper part inside the locking bush and movably mounted in the axial direction thereof, the stopper part having a locking position, in which it keeps the locking part penetrated in the locking recess of the threaded portion, and an opening position, in which it allows the locking part to move away from the locking recess; and

a load bearing member, such as a spring, between the body part and the stopper part to keep the stopper part normally in the stopping position;

whereby when the lifting member is installed in the projectile, a pressure rise inside the projectile pushes the stopper member from the locking position towards the opening position and, as the locking is released, it pushes the body part away from the projectile opening.

[0007] An essential idea of the invention is that the lifting member is provided with a separate threaded part and a lifting loop part mechanically locked thereto. A further essential idea of the invention is that there are separate releasing means which release the locking as a result of a mere pressure rise inside the projectile and allow the lifting loop member to detach from the threaded portion, the pressure thus pushing the lifting loop part out, whereby a large opening is formed in the space it occupied. According to an embodiment of the invention the threaded part is made of a plural number of separate sleeve parts, i.e. threaded pieces, coupled by a separate pressing member so that an outward movement of the lifting loop part from the locking position by a predetermined distance allows the portions of the threaded part to move towards each other, whereby also the portions of the threaded part disengage from the projectile and thus an even larger opening is achieved from inside the projectile into the open air.

[0008] An advantage of the invention is that the solution is simple to use because it is implemented only by mechanical parts that move in relation to one another. A further advantage of the invention is that it does not require the lifting loop or its parts to be heated, but a mere increase in pressure inside the projectile suffices. A yet further advantage of the invention is that a large opening from the inner projectile space into the open air is achieved, which enhances pressure drop and the flowing of explosive, if any, out of the projectile.

BRIEF DISCLOSURE OF THE FIGURES

[0009] The invention is disclosed in greater detail with reference to the accompanying drawings, in which

Figure 1 is a schematic view of a field artillery projectile provided with a lifting loop;

Figures 2a and 2b illustrate a partly sectional view of an embodiment of the invention;

Figure 3 is a cross-sectional view along line A-A of Figure 2a;

Figures 4a and 4b illustrate a partly sectional view of a second embodiment of the invention; and

Figures 5a and 5b illustrate a cross-sectional view along lines B-B and C-C of Figures 4a and 4b, respectively.

DETAILED DISCLOSURE OF THE INVENTION

[0010] Figure 1 is a schematic view of a field artillery shell 1 with a lifting member 2 at the tip thereof. The lifting member 2 is typically screwed to threads formed to the end of the shell for a primer, to which threads the primer needed to detonate the shell is screwed before the shell is discharged.

[0011] Figures 2a and 2b are schematic, partly sectional views of an embodiment of the invention. They show the lifting member 2 with a lifting loop 3 acting as a fastening member to which a hook or a similar lifting member is coupled for lifting a shell. The lifting member 2 has a body part 4 with the lifting loop 3 fastened thereto, the body part setting against the surface of the shell 1 when the lifting member 2 is screwed in place at the tip of the shell 1 .

[0012] Further, the lifting member 2 is provided with a separate threaded part 5 that has threads matching those of the shell 1 . On the side fac- ing the projectile, the body part 4 has a cylindrical locking bush 6, which sets inside the threaded part 5 when the lifting member 2 is normally assembled and extends into the opening in the projectile when the lifting member is installed thereto. The locking bush 6 has at least one, preferably 3 to 6 openings 6a, which are provided with locking parts 7. In this embodiment the locking parts 7 are wedge-shaped pieces extending through the locking bush 6 into locking recesses 5a provided in the threaded part 5. In this embodiment the locking part and, correspondingly, the locking recess 5a have a side facing the body part and provided with an inclined surface that rises towards the interior of the lifting member and, consequently, towards the centre of the body part.

[0013] Further, the lifting member 2 is provided a stopper part 8 inside the locking bush 6, the stopper part being substantially equal in size with the opening inside the locking bush. The stopper part 8 is fastened in place by a bolt 9 driven through the centre of the lifting loop 3, for example, so that its movement away from the body part 4 is restricted to extend no further than to the locking position. The stopper part 8 is thus capable of moving in the axial direction of the locking bush 6 in relation to the body part 4 and thereby also in relation to the locking bush 6 from the locking position towards the body part. Further, between the body part 4 and the stopper part 8 there is provided a spring 10 acting as a load bearing member and keeping the stopper part 8 in the locking position shown in Figure 2a for as long as there is no pressure inside the projectile.

[0014] Figure 2b shows a situation where the pressure inside the projectile has risen, due to which the stopper part 8 has moved from the position shown in Figure 2a towards the body part 4. This has released the locking part 7, thus allowing it to move from its normal position towards the centre part of the lifting member with the locking bush pushing it against the inclined surface towards the lifting loop 3. As a result, the impact of the pressure has allowed the body part to move into the position shown in Figure 2b, i.e. outward from the threaded part 5. This has enabled the body part 4 to detach from its normal position, and the pressure is capable of pushing it out completely, thereby creating an opening of a significant size from the inner projectile space into the open air in order to release the pressure.

[0015] Figure 3 shows a section along line A-A of Figure 2a. It illustrates the stopper part 8 inside the locking bush 6 and how it keeps the locking parts 7 penetrated in the locking recesses of the threaded part 5 so that the body part cannot come out of the threaded portion.

[0016] Figures 4a and 4b show a partly sectional view of a second embodiment of the invention. Its structure and operation mostly correspond to the solution shown in Figures 2a to 3, except that the locking part is a ball 7'.

[0017] In this embodiment, as Figures 5a and 5b clearly show, the threaded part is formed of three separate threaded pieces 5'. The threaded pieces 5' are provided with a recess 5b. Correspondingly, in this embodiment the threaded pieces 5' are provided with a resilient pressing member 1 1 around them, the pressing member being installed around the threaded pieces 5' during the assembly of the lifting member so that it tends to press the threaded pieces 5' against one another and towards the locking bush 6. In the situation of Figure 4a the threaded pieces 5' are in the locking position at a distance from one another and pressed against the locking bush 6, whereby they are unable to move towards each other but a gap 12 is left between their edges. This keeps them in a position where the lifting member 2 may be fastened by screwing it to the tip of the projectile, similarly as in the embodiment of Figures 2a to 3.

[0018] When the stopper part 8 has risen by impact of the pressure towards the lifting loop 3 so that the ball 7' may be expelled, the lifting loop 3 is capable of rising upward in relation to the threaded piece 5' until the locking bush 6 in its entirety has risen to the recess 5b formed in the threaded piece 5'. Resilient pressing members 1 1 , such as springs, rubber bands or the like, then press the threaded pieces 5' towards each other and they disengage from the threads of the projectile 1 so that a gap is left between the threaded pieces 5' and the projectile 1 . This allows the lifting member 2 in its entirety to detach from the projectile 1 , and the opening at the end of the projectile opens entirely, thus releasing the pressure in the projectile.

[0019] Figures 5a and 5b are schematic cross-sectional views along lines B-B and C-C of Figures 4a and 4b, respectively. Figure 5a shows how the edges of the threaded pieces 5' have a gap 12 between them to allow them to be pressed towards each other when the locking bush 6 has moved aside. Correspondingly, Figure 5b shows a situation where the threaded pieces 5' have moved towards the locking bush 6 so that they have become disengaged from the threads of the projectile 1 and may move away from the projectile. [0020] The above specification and the drawings disclose the invention by way of example only, the invention not being in any way restricted thereto, but the scope of protection is determined by the claims. The details of the embodiments disclosed in the different figures may be combined in desired manners. Hence the locking part may be a wedge-shaped piece, a ball or a similar piece which, when penetrated in the opening formed in the threaded part, prevents the lifting part and the threaded part from moving in relation to one another for as long as the stopper part is stopping it. At least one stopper part, although also more than one, typically 3 to 6 or even more, may be provided.

[0021] The stiffness of the spring 10 determines the pressure at which the stopper part 8 begins to move away from its stopping position, and the pressure is naturally to be chosen according to the situation at hand. A sealing of some kind is preferably provided between the stopper part 8 and the locking bush 6 to allow the pressure to push properly the stopper part 8. The idea of the operation of the locking part 7 is that the bottom surface of the opening in the locking bush rests against the surface of the locking part, and, correspondingly, the locking part surface that extends into the recess of the threaded part rests against the recess in the threaded portion, thus locking the body part and the threaded part together. Instead of the spring 10, also other resilient members and different resilient materials may be used.

[0022] The threaded piece may also have more than three parts, a minimum number that it can be implemented with being two, the parts having a width of clearly less than 180 degrees, for example 120 degrees, in the direction of the circumference.

[0023] Instead of a lifting loop, the fastening member may be a hook or some other commonly used member for lifting a projectile.