IL29536A - A delay means for a bomb fuse - Google Patents

Description

A delay means a fuse BOAS OF ISRAEL OF one to ensure displacement of the detonator into an arming position on the other in the case of a type to ensure generation of adequate current supply for the electronic signalling mechanism referred to It is an of the present invention to provide a delay means for a bomb fuse which enures the effective delaying of the arming of the detonator mechanism of the fuse for a predetermined According to the present invention there is a delay means a bomb fuse comprising an displaceable from a first position wherein it prevents movement of a detonator into an armed position to a seeond position wherein said detonator is to move into said armed a dash pot a piston forming part of said dash pot said element being associated with said piston so as to be displaceable spring biasing means bearding on said piston so as to bias it into movement against a predetermined fluid resistance so as to displace said element into said second a metallic strip having a first end secured to said said strip having a portion spaced from said first end and having formed therein a tapped aperture substantially aligned with an axis of said a rotary screw along a part of its length only and crewed through said tapped aperture of said metallic so as to be coupled via said strip to said piston so as to inhibit movement and rotary drive means coupled to screw shaft so as to rotatably displace said screw shaft thereby permit said displacement of said piston under said spring The screw shaft can of course be coupled to or be formed integrally with the axis of the impeller referred to In this case rotation of the impeller can only start upon launching or release of the bomb and therefore rotation of the screw shaft so as to allow for displacement of the piston can o begin once the bomb has been launched or The axial movement of the screw shaft as a result of its rotary movement always tends to take place at a greater speed than the movement of the piston under the influence of its spring biasing and against the fluid In other the rate of of the piston is only determined by the force exerted by the spring biasing means and by the sistance to movement exerted by the Thus the time taken for the piston to be displaced sufficiently for movement of the detonator into the armed position is always fixed this being the predetermined dela of the bomb The provision of the metallic strip which couples the screw shaft to the ensures the exertion of a braking effect on the rotation of the screw In this in the event that the screw shaft is formed integrally with or coupled to the axle of the impeller and the impeller operates an magnetic a braking effect is exerted upon the rotation of the impeller thereby preventing th generation of an adequate current supply from the generator for the arming of the signalling The arrangement is such that upon rotation of the rotary after a predetermined delay the metallic strip passes beyond the threaded portion of the Notary shaft under which circumstances the rotary shaft is freely One e of invention as applied to a proximity fuse will now by of tilth reference to the in which 1 and 2 show partially sectioned elevations of a in of in the the bomb fuse a a conical portion 1 and eubetantiaily cylindrical body portion 2 a screw threaded portion formed at an intermediate position on the body portion 2 so to enable the fuse to in the body of a A screw shaft 5 is coupled to an and into a cylindrical bore 6 in a rod 8 which depends downwardly from a 9 constituting part of a dash pot Only the portion of the shaft 5 is piston 9 comprises a circular disc portion 11 and a portion peripheral recess 13 is in the skirt portion 12 in which set a cup ring 14 formed of a resilient material which bears against the inner of the cylindrical body A small aperture 15 is formed in the piston rod 8 extends into a cavity 16 formed in a detonator housing 17 located in the body further cavities 18 are formed eccentric spaced positions in the housing one cavity being shown in the In these 18 are located compression springs 19 which boar at their lower ends on the bases of the cavities and at their u er insufficientOCRQuality

Claims (4)

1. A delay means for a bomb fuse comprising: (a) an element displaceable from a first position wherein it prevents movement of a detonator into an armed position to a second position wherein said detonator is free to move into said armed position, (b) a dash pot mechanism, (c) a piston forming part of said dash pot mechanism, (d) said element being associated with said piston so as to be displaceable therewith, (e) spring biasing means bearing on said piston so as to bias it into movement against a predetermined fluid resistance so as to displace said element into said second position, (f) a metallic strip having a first end secured to said piston, said strip having a portion spaced from said first end and having formed therein a tapped aperture substantially aligned with an axis of said piston, (g) a rotary screw shaft screw threaded along a part of its length only and screwed through said tapped aperture of said metallic strip., so as to be coupled via said strip to said piston so as to inhibit movement thereof, and (h) rotary drive means coupled to said screw shaft so as to rotatably displace said screw shaft and thereby permit said displacement of said piston under said spring ·

2. A delay means according to Claim 1, wherein said rotary drive means comprises an impeller of said bomb fuse and an impeller axle directly connected to said screw shaft. 29536/2 - 11 -

3. A delay means according to Claim 2, wherein said screw -¾ift includes an axial portion adjacent said impeller which is unthreaded and which is freely displaceable through said aperture.

4. A delay means for a bomb fuse substantially as hereinbefore described by way of example and with reference to the accompanying drawings. For the Applicants OLD C0HI AND PARTNERS ND: ΥΉ