FR2588649A1 - High-strength loading fork for underwater crossbows - Google Patents

Abstract

The invention relates to an underwater crossbow loading fork that lasts longer and does not present the dangers of wounds of other existing equipment. It consists of two rigid plastic sleeves a at the bottom of each of which a housing is formed to accommodate a half ball c on the one hand and an outward recess on the other; and of steel string b that is made as short as possible in order to avoid any strain-hardening effect at the point 3. The two essential characteristics are therefore: pivoting internally to the sleeves (ball-type pivot); and the shortest possible metal piece.

Description

 The arming device of a submarine crossbow, which allows the attachment of bungee cords on the arrow is generally composed of two sockets or warheads (a), screwed onto the bungee cords which have the male threaded ad hoc end , and a metal wire (piano cord (b)), about 2m / m in diameter.

 The piano cord has the shape of a V whose curved purity hangs on a notch practiced in the arrow.

 It is the frequent rupture of this part which poses the essential problem of the device.

 The rupture of the piano wire comes from the fact that the gunner, while arming, prints not only a longitudinal movement to the arming device (Stirrup), but also a lateral movement (Fig 3) having a shearing effect, after a few shots, from part 3.

 The remedy was sought in the articulation of the piano string (c) (Fig 4), or in increasing its elasticity (Fig 2) so as to avoid or delay shearing.

 In the second case (increase in elasticity), this effect is obtained by a spring loop (d), on each arm of the V, but this loop, if it actually increases the longevity of the stirrup, also increases the danger of injury to the fingers when it broke.

 Indeed, in the event of a break at point 3, during the arming of the crossbow, the shooter's fingers are inside the lines from bungee cords and are struck and torn by the spring loop, the danger is even greater in the event of wear of the notch of the arrow and departure of the bungee cords at the very moment or the pull of the shooter has just relaxed.

In the first case (joint) (Fig 4) the longevity of the stirrup is further increased, but the break tronsforms the central part, in the shape of a crescent, sharpened to penetrate into the notch of the arrow, like a real sickle, the fingers being in the position described above may be torn off for the same reasons: breakage, stall
The device which is the subject of this patent application has the effect of overcoming these drawbacks.

It has two main characteristics a) - maximum stiffening of the piano wire, sounds change the diameter
by an optimum shortening (this part, on our prototypes measures
45 m / m approx., Fixing included, against 140 m / m for devices
standards). This dimension is not limiting, and can still be
decreased, especially after shortening of the sockets also.

 In fact, the shorter a piece of a given diameter, the more difficult it is to twist.

b) - obtaining freedom of movement "all azimuths", and therefore, a fortiori lateral, by an articulation, internal to the socket, in order to avoid the dangers described above for the external articulations.

This articulation is carried out on our prototypes thanks to a ball joint, formed by a half sphere (c), riveted, or brayed on the ends of the piano string (the latter can also be simply twisted)
An increase in the hole in the socket, up to 3.5 m / m and more depending on the size of the hemisphere, as well as its flare outwards allows a lateral clearance of at least 600 between the axis of the rope and the axis of the socket. This travel is more than enough to avoid any direct effort on the metal part.

 The half sphere swivels "all over the place", giving a hemispherical housing inside the socket.

 The socket is made of rigid plastic.

This device is not limiting and can be achieved by any socket connection, piano-type homokinetic string (himispherical washer, spider, etc.)
The sleeve is grooved, ju only when the piano wire passes, so as to obtain a setting on the arrow, in armed position.

 Thus the danger is escorted, and the life of the stirrup increased.

 In addition the power of the crossbow is increased, the useful pulling distance of the bungee cords is extended by about 5 cm, i.e., for a standard crossbow equipped with bungee cords of 24 cm, 5 kG of additional thrust

Claims (5)

 1) Device called CALIPER ARMAMENT intended for submarine weapons characterized in that it comprises an articulation of the ball joint type internal to the sockets or warheads, a metal part shortened to the maximum.  2) Device according to claim 1, characterized in that it allows an all-round clearance of the sockets (a).  3) Device according to claim 1, corocterized by the fact that the metal part: piano wire (b), and half spheres (c), tsolidaires,) is shortened so as to delay any phenomenon of torsion and work hardening.  4) Device according to claims 1, 2 and 3, characterized in that it eliminates any risk of injury in the event of a break at point 3 of the piano wire.  5) Device according to claims 7 and 2 characterized in that the bushings are grooved to their end-so as to avoid as much as possible the risk of departure from the pure couse pivoting on the arrow, said bushings, due to traction bungee cords.