Transmission assembly with a telescopic universal joint, weapon having such a transmission assembly and method

#The subject of the present invention is that of a transmission assembly designed for an automatic weapon that includes a fixed part and a mobile part subjected to a recoil movement when the weapon is fired, the assembly having a driving motor arranged on the fixed part, a mechanism driven by the motor, which is integral with the mobile part, and a transmission device ensuring the transmission of power between the driving motor and the mechanism driven by the said motor. A transmission assembly of this type is known for weapons having a short recoil stroke of approximately 20 mm. The transmission device includes a set of gear wheels that slide over one another and enabling the recoil and counter-recoil stroke to be eliminated.

#This relatively simple solution is not applicable to weapons having a longer recoil stroke because of problems of elasticity, of proportion and geometric positioning of parts of weapons with longer recoil that can only be overcome at great additional expense.

#An object of the present invention is a transmission assembly of the afore-mentioned type, having a transmission device that can be applied to weapons having a large recoil stroke and that is easy to manufacture.

#The invention will become clearer after reading the description which follows, given by way of illustration, non-exhaustively, in reference to the appended drawings in which:

#FIG. 1a shows a side view of a weapon fitted with a transmission assembly according to the invention shown in a partial cross-section, and FIG. 1b is an an enlarged detail of FIG. 1a;

#FIG. 2a shows front cross section of a spline sleeve according to a preferred embodiment of the invention;

#FIGS. 1a and 1b show a small or medium caliber weapon having an external source of power, for example a machine gun, which has a motor 1 mounted on a fixed part of the weapon, in this case a weapon rest 11, by a plate 2.

#The weapon also includes a recoiling mass 20 mechanically linked to the cannon 40 of the weapon. A mechanism 30, particularly designed to ensure control of the weapon kinematics, i.e., the munition supply and the firing of the weapon, is mounted on the recoiling mass 20.

#Transmission between the motor 1 and the mechanism 30 is ensured by a universal joint which in the preferred embodiment shown has a first universal joint 5 driven by a part 4 integral with the driving shaft 3 of the motor 1, a spline shaft 6 having male splines 14 and which is driven by a part 16 located on the down side of the universal joint 5, a spline sleeve 7 having female splines 18 cooperating with the male splines 14 to ensure a drive which is integral in rotation with the shaft 6 and the sleeve 7, and a second universal joint 8 driven by its up side by a part 17 integral with the spline sleeve 7 and driving in turn by its down side a part 9 fitted with a drive gear 12 which transmits the movement to the kinematics 30 of the weapon via driven gear 10.