IL22134A - Piezoelectric generators for impact fuzes of ammunition - Google Patents

Description

PATENT ATTORNEYS 0 REINHOLD COHN MICHAEL COHN Π 3 D ISRAEL SHACHTER 213X6 PATENTS AND DESIGNS ORDINANCE SPECIFICATION Improvements to piezoelectric generators for o a Belgian of Jean Brussels Belgium do hereby declare the nature of this invention and in what manner the same is to be to be particularly described and ascertained in and by the following and more common use in electric fuses of ferroelectric materials and more particularly of barium sets an extremely important problem on depends the development and the of the on the one it is well known that the plesoeleotric effect does not only require an applied however hut that it also needs the presence of a deformation for securing the production of the necessary electric On the other when a highspeed there oocur the propagations of pressure waves can destroy the material without giving rise to the compressions which are indispensable for the production of electric These propagations are due to the which immediately produces plastic of even hydrodynaaio states in the She problem thus mainly consists of means preventing the collapse by break up of the electric material without at the same time the velocity of the actual and before the appearance in the generator of a noticeable compression for generating the necessary electric without diminishing the velocity of the there will be enabled the transfer to the at the of the static pressure capable of producing the deformation prior to the plesoeleotric Several proposals have already been made in order to parially damp the effects of the aforesaid Impact at the region of the or at least to very slightly delay the transmission of effects y between the actual and the tip of the a damping device or an elastic In accordance with a first proposal there was put over the generator an elastic cap which tie tip of the It was by this to delay the instant of actual of the ixapact effects to the delay involved is depending for instance on the of impact seeing that the deformation of the elastic can here place in An alternative to this proposal consists in the generator and the tip of the such an elastic cap so to as an insert and designed so as to be able to undergo a continuous tion until and including the when the effects of the impact are transmitted to the In if in kind of the deformations of elastic riuss can be readily than in the preceding and on the other there occurs a certain braking effect in the transmission of the effects to the it be admitted that the of pressure waves which are actually transmitted to the ferroelectric material practically also renders this means rather it has also been suggested to insert a spring between the generator and the tip of the This device may be considered as equivalent to the previous considering that the presence of such and particularly after being compressed until its windings are is not capable of bringing about the required reduction of the pressure wave The present invention concerns improvements contrary to the various means which have been suggested fulfill theessential condition which consists not only in securing a braking effect and a delay of the impact effort transmitted to the but also and mainly in securing simultaneously a reduction of the pressure wave so that this amplitude should not be altogether transmitted to the ferroelectric The result of the foregoing is that these ments make it possible to design electric fuses in such a way that even very high impact velocities of the projectile still be adopted whilst securing in the generator the deformation which is required for the piezoelectric even if the pressure wave at impact is itself sufficient for causing the destruction of the ferroelectric without creating the required compression The according to the present tion essentially consist in in front of the electric in a totally closed housing with rigid an elastic the volume of which is slightly smaller than that of the housing This is placed between the generator and the tip of the It will generally consist of an elastic such as natural or artificial rubber of a shape which is slightly different from that of its housing in order to leave a certain spacing between The housing shall preferably be defined by a fixed part and a part to aforesaid mobile part being under the effect of the to move in the axial being duly guided by the fixed part in order to compress and distortaforesaid the pressure waves being thus partially absorbed by the latter under predetermined conditions and the transmission to the generator of the pressure waves whose intensity has thus been reduced taking place under the optimum conditions required for obtaining the piezoelectric These improvements make it possible for the specialist in these to with a considerable amount of the manufacture and the design of electric fuses achieving an design for the rigid and entirely closed the shape of the and the means for securing the transmission of the damped pressure waves to the For this purpose it is in accordance with the present invention to insert with considerable between aforesaid fixed part of the rigid and entirely closed housing of the and the actual generator simple means such for a ball for correctly directing aforesaid transmission of the pressure waves to the Aforesaid characteristic elements may of course be applied and used in various forms and according to the Merely by way of and without implying any restrictive one form of embodiment is described in further detail with reference to e a ended awin s of 1 illustrates a radial section of an improved piezoelectric generator to t e present in in its resting or standby 2 is similar to but the generator is represented the position following an Referring to the the 1 is placed in a housing 7 provided between the 2 and the generator 3 with the help of the pistons and of an intermediate ball shape dimensions of the housing 7 are such that there is in aforesaid housing 7 at least one free spaee 8 between 1 and the wall of housing between the volumes of aforesaid housing 7 and aforesaid 1 is sufficiently large so as to prevent the pressure waves from being transmitted to the generator but is not sufficiently large so as to delay the application of the pressure to the As as 1 fills the whole volume of housing it can practically not he compressed any further in this it transmits the impact e 1 is preferably made of rubber of such on account of its comparatively low density and the velocity with which sound is transmitted through the actual rubber aforesaid 1 prevents passage of the pressure t results therefrom when an impact the generator is first of all subjected to an increasing force due to the gradually increasing deformation of the to a force corresponding to the maximum compression of rubber and to the stress of the impact through 7 of the intermediate ball β as a ball joint the nose d the generator 3 will a better of over the whole area of generator even if impact happens to be at a It possibl to use any other type of construction eapable producing equivalent difference of between the 1 and the housing which is entirely closed by rigid may either be due to a difference of to a ence of or also to the presence of hollow parts provided either in the in its or in both of In one very particular form of the free spaces between the actual and the housing may be filled by a material is considerably more deferrable and than the actual This kind of construction might for instance be applied by g a consisting of at least two different of which would the actual whilst the other would act as a filler with a higher elasticity than the actual She present invention concerns such an improved electric fuse as as any projectile fitted insufficientOCRQuality

Claims (1)

1. 8 A pieisoelectric fuze for a projectile comprising electric generator wherein an elastic is fitted into a closed housing in front of the the volume of the elastic being slightly less than that of the housing which latter volume is adapted to decrease upon impact of the A according to wherein the pad has a shape which di fers from that of the closed in order to provide some free A fuze according to wherein the pad has the same shape but smaller dimensions than the closed housing in order to provide some free A fuze according to Claim wherein the pad has the same shape and the same outer dimensions as the closed housing but comprises hollow in order to provide some free A fuze according to any one of the previous wherein the closed housing for the is defined by the hollow nose of the fuze and a piston slidable in said hollow the being adapted to on the one hand against the inner wall of said hollow nose and on the other hand against the A fuze according to Claim wherein the piston forming one of the walls of the closed housing bears against one of the faces the generator through the intermediary of a 9 A piezoelectric for projectile s desoribed herein with to the accompanying dra Dated this 22nd day of 1964 insufficientOCRQuality