the crossbow 1 consists in essence of the shaft 2 , the base frame 3 , as well as of the projectile support 4 . tensioning members 6 , 6 &# 39 ; are mounted on both sides on the base frame 3 at points 5 , 5 &# 39 ;, with universal joints . in the base frame 3 , provision is made below the projectile support 4 for a spring assembly 7 which is connected to the propelling arms 10 , 10 &# 39 ; via a pivotable component 8 and via cords 9 , 9 &# 39 ;, the string 11 being secured between the ends of the propelling arms 10 , 10 &# 39 ;. the springs assembly 7 may be a stack of cup springs or plate springs . the length of the cords 9 , 9 &# 39 ; can be adjusted by means not shown herein . it is also possible to mount the pivotable component 8 with a universal joint , whereby the spring force of the spring assembly 7 would automatically be evenly distributed over both propelling arms 10 , 10 &# 39 ; in the direction of arrow 2 . the cords 9 , 9 &# 39 ; are carried over cam segments 12 , 12 &# 39 ; so as to obtain a transmission leverage for the easier tensioning of the spring assembly 7 as the propelling arms 10 , 10 &# 39 ; are being tensioned . at the same time , the movement and hence the speed , of the propelling arms 10 , 10 &# 39 ; can be controlled by determining the shape of the cam segments 12 , 12 &# 39 ;. for tensioning the propelling arms 10 , 10 &# 39 ;, the arresting means 13 , not here described in greater detail , which may consist of catches which engage in each other under a spring force , are released and swung forward until the hooks 14 , 14 &# 39 ; engage behind the propelling arms 10 , 10 &# 39 ;. subsequently the tensioning members 6 , 6 &# 39 ; are pivoted with the exertion of force against the spring force of the spring assembly 7 until the string 11 can be placed into the string holder 15 . the tensioning members 6 , 6 &# 39 ; can then be arrested above the shaft 2 , whereby the propelling arms 10 , 10 &# 39 ; are held fast and the crossbow 1 is thus secured , even when the propelling arms 10 , 10 &# 39 ; are tensioned . since in this position the propelling arms 10 , 10 &# 39 ; bear on the base frame 3 , the crossbow 1 as a whole is then very narrow , which facilitates a simple carriage or packing . when the tensioning members 6 , 6 &# 39 ; are brought into their position shown in fig2 the hooks 14 , 14 &# 39 ; no longer engage behind the propelling arms 10 , 10 &# 39 ;, so that the crossbow is then ready for shooting . a lever 16 , arranged on the base frame 3 for pivoting round the axis 17 , is adjustable in height at the front in a slot 19 by means of a clamping screw 18 . next to the slot 19 is a scale 20 , to permit an exact setting of the sight 21 fitted on the lever 16 . the triggering device 22 consists of a tensioning bolt 23 which is displaced in the direction of arrow 26 against a spring acting in the direction of arrow 25 , by means of an actuating lever 24 so as to tension the triggering device 22 in this way . in this action , the safety element 27 is displaced to bring its catch 29 under the catch 30 on the tensioning bolt 23 , by means of a spring acting in the direction of arrow 28 . at the same time , the component 32 connected to the trigger 31 is displaced under the tensioning bolt 23 by a spring which acts in the direction of arrow 33 . for freeing the triggering device 22 , the safety element 27 is displaced by the actuating lever 34 against the force of the above mentioned spring , until the actuating lever 34 enters the upward limb of the angular slot to reach into the position 35 and be secured therein . if the trigger 31 is then actuated , which only requires a very small expenditure of force when the triggering device 22 is unlocked , the tensioning bolt 23 is released and is impelled under the spring force in the direction of arrow 25 to strike the lever 36 , whereby it releases the arresting means 37 of the string holder 15 that is pivoted by a spring acting in the direction of arrow 38 , and thereby releases the string 11 . at the same time an element 39 , which is connected to the tensioning bolt 23 , presses on the actuating lever 34 and pushes the latter out of its secured position 35 , so that after the shot the safety element 27 is automatically displaced again under the spring force into the safety position . if the trigger 31 is inadvertently actuated when the triggering device 22 has not been released , the tensioning bolt 23 is only displaced until the catches 29 and 30 engage in each other , without the tensioning bolt 23 touching the lever 36 . it is then also not possible to release the shot by the displacement of the safety element 27 by means of the actuating lever 34 , since the tensioning bolt 23 has first to be retensioned again . only then can the crossbow 1 be unlocked again by the actuating lever 34 . for reliable aiming , the tensioning members 6 , 6 &# 39 ; can be swung down into the position drawn in dashes in fig2 so as to be used as a support for the crossbow 1 .