Patent Description:
Some current projectile guiding kits include a rear unit adapted to be connected at its rear end to a front end of a projectile and a front unit rotatably connected at its rear end to a front end of the rear unit. Typically, there is a small gap between the rear unit and the front unit to ensure uninterrupted relative rotation of the front unit with respect to the rear unit. These guiding kits typically include one or more bearings assembly positioned in, or proximal to, the gap between the rear unit and the front unit to enable the rotation of the front unit with respect to the rear unit.

In order to ensure proper operation of these guiding kits upon firing of the projectile, it is necessary to prevent dust and/or dirt from entering the gap and dirt the bearing(s). Accordingly, these guiding kits typically include a covering that is adapted to cover the gap between the rear unit and the front unit of the kit while the projectile is not in use.

Typically, the coverings thereof have to be manually removed from the kit, for example prior to feeding the projectile into a firing chamber of a weapon. This operation may be time consuming (especially when large number of projectiles or fast firing are needed) and/or may prevent using such projectile guiding kits with projectiles for automatic weapons. Furthermore, dust and dirt accumulated within the firing chamber of the weapon may also enter the gap and dirt the bearing(s) of the guiding kit.

Accordingly, there is a need in a device for sealing projectile guiding kits during the entire life time of the kit prior to the commencing of the relative rotation following the actual firing of the projectile. Korean patent publication <CIT> discloses a decoupling bearing module for a guided missile which minimizes the risk of damage by absorbing impact of launching if the launching impact of a projectile is generated. The decoupling bearing module for a guided missile comprises a rotary shaft, a pair of bearing inner wheels, a pair of bearing outer wheels, a pair of connectors, and a plastic deformation ring in a round shape. The plastic deformation ring in a round shape is protruded to one surface among one end surface of a controller and one end surface of an air frame for preventing contact with each other. The plastic deformation ring absorbs launching impact of a projectile by plastic deformation if one end surface of the controller and one end surface of the air frame come close through the launching impact of the projectile. <CIT> discloses a connecting assembly for connecting a dome covering a seeker head with the structure of a missile. A holding ring extends over the rim of said dome, positively holding this dome and connected with the structure of the missile. An annular recess is provided underneath the holding ring along the rim of the dome. This recess contains a flexible sealing substance for establishing a seal between the holding ring and the dome. It is important, that no additional material bonding such as cementing or soldering is provided between the dome and the holding ring.

One aspect of the present invention, in accordance with claim <NUM>, provides a device for sealing a projectile guiding kit having a rear unit adapted to be connected at its rear end to a front end of a projectile and a front unit rotatably connectable at its rear end to a front end of the rear unit, the device includes:
an annular body adapted to envelope at least a front portion of the rear unit and at least a rear portion of the front unit of the guiding kit; and a flexible ring-shaped strip attached to an inner side and close to a front end of the annular body, the ring-shaped strip is adapted to seal a gap between the rear unit and the front unit of the guiding kit at a connection region therebetween; wherein the annular body is adapted to slide towards the rear unit of the guiding kit when subjected to a longitudinal acceleration that exceeds a predetermined acceleration value, thereby uncovering the gap and enabling uninterrupted rotation of the front unit with respect to the rear unit of the guiding kit.

In some embodiments, the device further includes a trapping unit adapted to be connected to the rear unit of the guiding kit and adapted to do at least one of: support at least a rear end of the annular body to prevent unintended sliding of the annular body towards the rear unit of the guiding kit; and lock the annular body of the device with respect to the rear unit of the guiding kit upon sliding of the annular body thereto.

In some embodiments, the trapping unit includes an annular plate adapted to be connected to the rear end of the rear unit of the guiding kit and includes at least one first protrusion that protrudes outwards from the annular plate and arranged to support the rear end of the annular body and to prevent the unintended sliding of the annular body.

In some embodiments, the trapping unit includes an annular plate adapted to be connected to the rear end of the rear unit of the guiding kit and includes at least one second protrusion that protrudes outwards from the annular plate, the annular body includes an indent along at least a portion of a circumference of the inner side of the annular body between the ring-shaped strip and the rear end of the annular body, and wherein the at least one second protrusion of the trapping unit is adapted to enter into the ident of the annular body to thereby lock the annular body with respect to the rear unit of the guiding kit upon sliding of the annular body thereto.

In some embodiments, the device includes at least one front stopper adapted to be connected to the front unit of the guiding kit and adapted to prevent unintentional sliding of the annular body towards the front unit of the guiding kit.

In some embodiments, a portion of the inner side of the annular body that is adjacent to a rear end of the annular body is tapered in a direction extending from the rear end to the front end of the annular body and adapted to rest on corresponding portion of a projectile upon sliding of the annular body thereto.

In some embodiments, an outer side of the annular body is tapered in a direction extending from a rear end to the front end of the annular body.

Another aspect of the present invention, in accordance with claim <NUM>, provides a projectile guiding kit adapted to be connected to a projectile, the kit includes:
a rear unit adapted to be connected at its rear end to a front end of the projectile; a front unit rotatably connected at its rear end to a front end of the rear unit; and the device according to the first aspect of the present invention.

In some embodiments, the projectile guiding kit further includes a trapping unit adapted to be connected to the rear unit and adapted to at least one of: support at least a rear end of the annular body to prevent unintended sliding of the annular body towards the rear unit; and lock the annular body with respect to the rear unit upon sliding of the annular body thereto.

In some embodiments, the trapping unit includes an annular plate adapted to be connected to the rear end of the rear unit of and includes at least one first protrusion that protrudes outwards from the annular plate and arranged to support the rear end of the annular body and to prevent the unintended sliding of the annular body.

In some embodiments, the trapping unit includes an annular plate adapted to be connected to the rear end of the rear unit and includes at least one second protrusion that protrudes outwards from the annular plate, the annular body includes an indent along at least a portion of a circumference of the inner side of the annular body between the ring-shaped strip and the rear end of the annular body, and wherein the at least one protrusion of the trapping unit is adapted to enter into the ident of the annular body to thereby lock the annular body with respect to the rear unit upon sliding of the annular body thereto.

In some embodiments, the front unit includes at least one front stopper adapted to prevent unintentional sliding of the annular body towards the front unit.

These, additional, and/or other aspects and/or advantages of the present invention are set forth in the detailed description which follows; possibly inferable from the detailed description; and/or learnable by practice of the present invention.

The device may also improve the aerodynamic feature of a projectile. The projectile is having a front part and a rear part. The external diameter of the front part of the projectile is larger than the external diameter of the front end of a rear part of the projectile. The front end of the rear part of the projectile is conical having larger diameter at locations behind the front end. For improving the aerodynamic feature of the projectile, the device comprises an annular cut-off cone sleeve slidably disposable over the front part of the projectile. The diameter of the narrower end of the annular cone sleeve is slightly larger than the diameter of the front part of the projectile and the length of the annular cut-off cone sleeve is larger than the distance between the front end of the rear part of the projectile and a location on rear part having a diameter equal to the diameter of the rear end of the annular cut-off cone sleeve.

In some embodiments the annular cut-off cone sleeve is adapted to slide from a rearmost position backwardly in response to longitudinal firing acceleration force.

In some embodiments the annular cut-off cone sleeve is adapted to slide from a rearmost position backwardly in response to manually operated force.

In some embodiments the annular cut-off cone sleeve comprises a dent made in its internal face at a location facing against the rear end of the front part of the projectile when the cone sleeve is in its frontmost position.

In some embodiments the device further comprising a secure-and-lock ring disposed between the front part and the rear part of the projectile, the secure-and-lock ring comprises at least one lug protruding from the ring outer circumference.

In some embodiments the at least one lug is located in the dent of the cone sleeve when the cone sleeve is in its frontmost position.

In some embodiments the at least one lug is adapted to bend in response to sliding of the cone sleeve backwardly.

In some embodiments the at least one lug is adapted to touch the inner face of the cone sleeve when it is bent in a defined angle.

For a better understanding of embodiments of the invention and to show how the same can be carried into effect, reference will now be made, purely by way of example, to the accompanying drawings in which like numerals designate corresponding elements or sections throughout.

It will be appreciated that, for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale.

In the following description, various aspects of the present invention are described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the present invention. However, it will also be apparent to one skilled in the art that the present invention can be practiced without the specific details presented herein. Furthermore, well known features can have been omitted or simplified in order not to obscure the present invention. With specific reference to the drawings, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention can be embodied in practice.

Before at least one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is applicable to other embodiments that can be practiced or carried out in various ways as well as to combinations of the disclosed embodiments.

The terms "front" and "rear" as used herein represent orientation of the disclosed devices/kits with respect to a projectile to be used with, and specifically, these relative directions/locations relate to the direction of flight of the projectile, when fired, as "forward".

Generally, a device for sealing a projectile guiding kit is disclosed. Some projectile guiding kits may include a rear unit adapted to be connected at its rear end to a front end of a projectile and a front unit rotatably connected at its rear end to a front end of the rear unit. The kits may include one or more bearings positioned in, or proximal to, a gap between the rear unit and the front unit to enable the rotation of the front unit with respect to the rear unit.

The disclosed device may be adapted to seal the gap between the rear unit and the front unit of the projectile guiding kit for the entire life time of the guiding kit/projectile prior to actual firing of the projectile. The device may be adapted to slide towards the rear unit of the guiding kit upon firing of the projectile, when the device is subjected to a longitudinal acceleration that exceeds a predetermined acceleration value and/or when subjected to a longitudinal aerodynamic force that exceeds a predetermined longitudinal force value. The sliding thereof may uncover the gap between the rear unit and the front unit of the guiding kit, thereby enabling uninterrupted rotation of the front unit with respect to the rear unit according to the aerodynamic forces applied thereon and provide proper operation of the kit thereof.

Advantageously, the disclosed device need not be removed from the guiding kit prior to firing of the projectile. For example, the projectile may be fed into a firing chamber of a weapon without detaching/releasing the device from the guiding kit. Accordingly, the disclosed device may seal sensitive elements of the projectile guiding kit (such as bearing(s) between the rear unit and the front unit thereof) all the way up to actual firing of the projectile. Furthermore, the disclosed device may save time and reduce personnel's effort required to prepare the projectile for firing and/or enable usage of the guiding kit with projectiles in automatic weapons. This is in contrast to current covering for the projectile guiding kit that has to be manually released/detached from the guiding kit prior to feeding the projectile into the weapon's firing chamber.

Reference is now made to <FIG>, which are schematic illustrations of a projectile guiding kit <NUM> for a projectile <NUM>. <FIG> shows and exploded side view and <FIG> shows an assembled side view of guiding kit <NUM>.

Projectile guiding kit <NUM> may have a rear unit <NUM> adapted to be connected at its rear end 92a to a front end <NUM> of a projectile <NUM> and a front unit <NUM> rotatably connected at its rear end 94a to a front end 92b of rear unit <NUM>. Projectile guiding kit <NUM> may have one or more bearings <NUM> positioned within, or proximal to, a gap <NUM> between rear unit <NUM> and front unit <NUM> to enable the rotation of front unit <NUM> with respect to rear unit <NUM>.

Reference is now made to <FIG>, which are schematic illustrations of a device <NUM> for sealing a projectile guiding kit <NUM>, according to some embodiments of the invention. Reference is also made to <FIG>, which is a schematic illustration of a projectile guiding kit <NUM> and device <NUM> for sealing projectile guiding kit <NUM>, according to some embodiments of the invention. Reference is also made to <FIG>, which is a schematic illustration of a projectile guiding kit <NUM> and a device <NUM> for sealing projectile guiding kit <NUM>, prior to and after firing of a projectile <NUM>, according to some embodiments of the invention.

<FIG> shows a side view, <FIG> shows a top view, <FIG> shows a bottom view and <FIG> shows a cross-sectional view of device <NUM>. <FIG> and <FIG> show a cross-sectional view of device <NUM> and of projectile guiding kit <NUM>.

According to some embodiments, device <NUM> may be used with any projectile guiding kit having two or more rotatably connectable units. For example, device <NUM> may be used with projectile guiding kit <NUM> described above with respect to <FIG>.

Device <NUM> may include an annular (or substantially annular) body <NUM>. Annular body <NUM> may have a front end 111a, a rear end 111b, an inner side 112a and an outer side 112b (e.g., as shown in <FIG>).

Device <NUM> may have a flexible ring-shape strip <NUM>. Ring-shape strip <NUM> may be attached to annular body <NUM> at inner side 112a and adjacent or close to front end 111a of annular body <NUM> (e.g., as shown in <FIG>). In some embodiments, ring-shape strip <NUM> is attached to annular body <NUM> along the entire circumference of inner side 112a of annular body <NUM> (e.g., as shown in <FIG>). In some embodiments, flexible ring-shape strip <NUM> may be made of a rubber.

According to some embodiments, annular body <NUM> of device <NUM> may be adapted to envelope at least a front portion of rear unit <NUM> and at least a rear portion of front unit <NUM> of projectile guiding kit <NUM>. For example, annular body <NUM> may be adapted to envelope the entire (or substantially entire) rear unit <NUM> and a portion of front unit <NUM> of guiding kit <NUM> that is adjacent to rear end 94a of front unit <NUM> (e.g., as shown in <FIG>). Device <NUM> may be retrofit onto existing projectile guiding kits (e.g., such as guiding kit <NUM>, as shown in <FIG>).

Ring-shaped strip <NUM> may be adapted to tightly seal gap <NUM> between rear unit <NUM> and front unit <NUM> when device <NUM> is used with guiding kit <NUM>. For example, <FIG> shows ring-shape strip <NUM> sealing gap <NUM> when annular body <NUM> envelopes respective portions of rear unit <NUM> and front unit <NUM>.

Annular body <NUM> of device <NUM> may be adapted to slide towards rear unit <NUM> of guiding kit <NUM> when subjected to a longitudinal acceleration that exceeds a predetermined acceleration value and/or when subjected to a longitudinal aerodynamic force that exceeds a predetermined longitudinal force value. In some embodiments, the predetermined acceleration value is no less than <NUM>. In some embodiments, the predetermined longitudinal force value is no less than <NUM> N.

For example, <FIG> illustrates sliding of annular body <NUM> towards rear unit <NUM> of guiding kit <NUM> upon firing of projectile <NUM>. The sliding of annular body <NUM> may uncover gap <NUM> (e.g., that may be sealed by flexible ring-shape strip <NUM> prior to firing), thereby enabling uninterrupted rotation of front unit <NUM> of guiding kit <NUM> with respect to rear unit <NUM> thereof.

Upon firing of projectile <NUM> and during the flight of projectile <NUM>, aerodynamic forces applied on annular body <NUM> of device <NUM> may push annular body <NUM> towards rear unit <NUM> of guiding kit <NUM>, thereby ensuring that gap <NUM> between rear unit <NUM> and front unit <NUM> thereof remains uncovered to enable uninterrupted rotation of front unit <NUM> with respect to rear unit <NUM>.

In some embodiments, annular body <NUM> of device <NUM> is adapted to slide and rest on projectile <NUM> upon firing thereof. In these embodiments, a portion <NUM> of inner side 112a that is adjacent to rear end 111b of annular body <NUM> may be adapted in shape and size to receive corresponding portion of projectile <NUM> (e.g., as shown in <FIG> and <FIG>). For example, portion <NUM> may be tapered in a direction extending from rear end 111b towards front end 111a of annular body <NUM>.

In some embodiments, outer side 112b of annular body <NUM> is tapered in the direction extending from rear end 111b towards front end 111a of annular body <NUM> (e.g., as shown in <FIG> and <FIG>). The tapered shape thereof may be designed to ensure that annular body <NUM> does not affect (or substantially does not affect) the aerodynamic parameters of projectile <NUM> and/or of guiding kit <NUM>.

According to various embodiments, mechanical parameters of device <NUM> (e.g., of annular body <NUM> and/or of flexible ring-shape strip <NUM>) are determined to prevent unintended sliding of annular body <NUM> prior to firing of projectile <NUM> and also to enable sliding of annular body <NUM> toward rear unit <NUM> of guiding kit <NUM> upon firing of projectile <NUM> (e.g., as shown in <FIG>). The mechanical parameters may, for example, include dimensions, material and/or mechanical properties of annular body <NUM> and/or of flexible ring-shape strip <NUM>.

For example, dimensions of annular body <NUM> and/or of flexible ring-shape strip <NUM> and/or mechanical properties of flexible ring-shape strip <NUM> may be determined to provide a desired friction force between flexible ring-shape strip <NUM> and the respective portions of rear unit <NUM> and front unit <NUM> of guiding kit <NUM>. In some embodiments, the desired friction force may be no less than <NUM>-<NUM> N.

In this manner, annular body <NUM> may provide sealing of gap <NUM> between rear unit <NUM> and front unit <NUM> of guiding kit <NUM> during the entire life time of projectile <NUM> prior to actual firing thereof without disturbing the operation of guiding kit <NUM> upon firing and during the flight of projectile <NUM>.

It is noted that for simplicity and clarity of illustration, elements shown in <FIG> have not necessarily been drawn to scale. It is further noted that the shape and dimensions of device <NUM> and/or annular body <NUM> are determined to ensure that device <NUM> and/or annular body <NUM> does not affect (or substantially does not affect) the aerodynamic forces applied on and/or the aerodynamic parameters of guiding kit <NUM> and/or on projectile <NUM> during flight of projectile <NUM>.

Reference is now made to <FIG>, <FIG> and <FIG>, which are schematic illustrations of a device <NUM> for sealing a projectile guiding kit <NUM> and including a trapping unit <NUM> and at least one front stopper <NUM>, according to some embodiments of the invention. Reference is also made to <FIG>, which are schematic illustrations of a projectile guiding kit <NUM> and a device <NUM> for sealing projectile guiding kit <NUM> and including a trapping unit <NUM> and at least one front stopper <NUM>, according to some embodiments of the invention. Reference is also made to <FIG>, which is a schematic illustration of a device <NUM> for sealing a projectile guiding kit <NUM> and including a trapping unit <NUM> and at least one front stopper <NUM>, prior to and after firing of a projectile <NUM>, according to some embodiments of the invention.

<FIG> shows a side view, <FIG> shows a top view, <FIG> shows a first cross-sectional view and <FIG> shows a second cross-sectional view of device <NUM>. <FIG> show the first cross-sectional view and the second cross-sectional view, respectively, of device <NUM> and of projectile guiding kit <NUM>, according to some embodiments of the invention. <FIG> shows the first cross-sectional view of device <NUM> and of projectile guiding kit <NUM> prior to and upon firing of projectile <NUM>.

According to various embodiments, device <NUM> may include a trapping unit <NUM> and/or at least one front stopper <NUM>.

According to some embodiments, trapping unit <NUM> may be adapted to prevent unintentional sliding of annular body <NUM> towards rear unit <NUM> of guiding kit <NUM> prior to firing of projectile <NUM>. This is in addition to the friction forces between flexible ring-shape strip <NUM> and the respective portions of rear unit <NUM> and front unit <NUM> of guiding kit <NUM> (e.g., as described above with respect to <FIG>).

In some embodiments, trapping unit <NUM> may be adapted to lock annular body <NUM> upon sliding of annular body <NUM> towards rear unit <NUM> of guiding kit <NUM>, upon firing of projectile <NUM>. In this manner, gap <NUM> between rear unit <NUM> and front unit <NUM> of guiding kit <NUM> may be kept uncovered upon firing of projectile <NUM>, independently of aerodynamic forces that are applied on annular body <NUM> during the flight of projectile <NUM>.

According to some embodiments, trapping unit <NUM> includes an annular (or substantially annular) trapping plate <NUM>, one or more first protrusions <NUM> and one or more second protrusions <NUM>.

Annular plate <NUM> may have a front side 142a and a rear side 142b and a central opening 142c (e.g., as shown in <FIG>). Annular plate <NUM> may be adapted to be connected to rear unit <NUM> of guiding kit <NUM>. For example, annular plate <NUM> may be adapted to be connected to rear end 92a of rear unit <NUM> while yet enabling connection of rear end 92a of rear unit <NUM> to front end <NUM> of projectile <NUM> (e.g., as shown in <FIG> and<FIG>). In some embodiments, annular plate <NUM> may include one or more holes <NUM> to enable connection of annular plate <NUM> to rear unit <NUM> of guiding kit <NUM> (e.g., as shown in <FIG>).

First protrusion(s) <NUM> may generally protrude outwards from annular plate <NUM> (e.g., as shown in <FIG>, <FIG> and <FIG>). In some embodiments, first protrusion(s) <NUM> are inclined at a predetermined angle <NUM> with respect to a plane of annular plate <NUM> in a direction extending from front side 142a to rear side 142b of annular plate <NUM> (e.g., as shown in <FIG> and <FIG>). Angle <NUM> is indicated in <FIG> only (for sake of clarity). In some embodiments, angle <NUM> ranges between <NUM>°-<NUM>°.

First protrusion(s) <NUM> may be arranged to support annular body <NUM> (or at least rear end 111b of annular body <NUM>) prior to firing of projectile <NUM> (e.g., as shown in <FIG>), while enabling sliding of annular body <NUM> towards rear unit <NUM> of guiding kit when subjected to the predetermined longitudinal acceleration and/or the predetermined longitudinal force.

Second protrusion(s) <NUM> may generally protrude outwards from annular plate <NUM> (e.g., as shown in <FIG> and <FIG>). In the embodiments of <FIG> and <FIG>, annular body <NUM> of device <NUM> may further include an indent <NUM> (e.g. a circular indent) made on inner side 112a of annular body <NUM>, between ring-shaped strip <NUM> and rear end 111b of annular body <NUM> and at a predetermined distance <NUM> with respect to ring-shaped strip <NUM> (e.g., as shown in <FIG>). Distance <NUM> is indicated in <FIG> only (for sake of clarity). In some embodiments, indent <NUM> is made along at least a portion of the circumference of inner side 112a of annular body <NUM>.

Annular plate <NUM> and/or first protrusion(s) <NUM> and/or second protrusion(s) <NUM> may be made of, for example, flexible/bendable metal. The mechanical parameters of the flexible/bendable metal may be determined to enable mostly plastic (e.g., irreversible) bending of first protrusion(s) <NUM> and/or of second protrusion(s) <NUM> when, for example, a force applied thereon by annular body <NUM>, exceeds a predetermined force value (e.g., force of <NUM> N, for example upon firing of projectile <NUM>) while yet enabling a desired measure of elastic deformation of first protrusion(s) <NUM> and/or of second protrusion(s) <NUM> upon the plastic bending thereof.

Upon firing of projectile <NUM>, annular body <NUM> of device <NUM> may slide towards rear unit <NUM> of guiding kit <NUM>, while bending first protrusion(s) <NUM> and/or second protrusion(s) <NUM> and enabling second protrusion(s) <NUM> to enter into indent <NUM> of annular body <NUM>, thereby locking annular body <NUM> with respect to rear unit <NUM>. The distance between indent <NUM> and ring-shaped strip <NUM> may be determined based on dimensions of annular body <NUM> and/or of rear unit <NUM> to ensure that when annular body <NUM> is locked with respect to rear unit <NUM> by second protrusion(s) <NUM> of annular plate <NUM>, gap <NUM> remains uncovered (e.g., as shown in <FIG>).

According to some embodiments, front stopper(s) <NUM> may be adapted to be connected to front unit <NUM> of guiding kit <NUM> (e.g., as shown in <FIG>). Front stopper(s) <NUM> may prevent unintended sliding of annular body <NUM> of device <NUM> towards front unit <NUM> of guiding kit <NUM>.

According to some embodiments, relative positions of annular plate <NUM> / first protrusion(s) <NUM> of trapping unit <NUM> with respect to front stopper(s) <NUM> may be determined to ensure that ring-like strip <NUM> attached to annular body <NUM> tightly seals gap <NUM> between rear unit <NUM> and front unit <NUM> of guiding kit <NUM> prior to firing of projectile <NUM>.

Reference is now made to <FIG>, which are schematic illustrations of a projectile guiding kit <NUM> for a projectile <NUM>, according to some embodiments of the invention. <FIG> shows and exploded side view and <FIG> shows an assembled side vide of guiding kit <NUM>.

According to some embodiments, projectile guiding kit <NUM> includes a rear unit <NUM> adapted to be connected at its rear end <NUM> to a front end <NUM> of a projectile <NUM> and a front unit <NUM> rotatably connected at its rear end <NUM> to a front end <NUM> of rear unit <NUM>. Projectile guiding kit <NUM> may have one or more bearings <NUM> positioned within, or proximal to, a gap <NUM> between rear unit <NUM> and front unit <NUM> to enable the uninterrupted rotation of front unit <NUM> with respect to rear unit <NUM>.

According to some embodiments, projectile guiding kit <NUM> includes a device <NUM> for sealing projectile guiding kit <NUM>. Device <NUM> may be similar to device <NUM> described above with respect to <FIG>, <FIG> and <FIG> and <FIG>, <FIG>, <FIG>, <FIG> and <FIG>.

Advantageously, the disclosed device for sealing projectile guiding kits needs not be removed from the guiding kit connected to the projectile prior to firing of the projectile. For example, the projectile may be fed into a firing chamber of a weapon without detaching/releasing the device from the guiding kit. Accordingly, the disclosed device may seal sensitive elements of the projectile guiding kit (such as bearing(s) between the rear unit and the front unit thereof) all the way up to actual firing of the projectile. Furthermore, the disclosed device may save time and reduce personnel's effort required to prepare the projectile for firing and/or enable usage of the guiding kit with projectile for automatic weapons. This in contrast to current covering for the projectile guiding kit that has to be manually released/detached from the guiding kit prior to feeding the projectile into the weapon's firing chamber.

In some known conditions, a cannon shell and a projectile may be equipped with an oversized warhead, that is the - outer diameter of the warhead (the front part of the object, with respect to the trajectory direction) may be substantially different from that of the projectile, and typically larger that that of the projectile at the rearmost end of the projectile, where the warhead is adapted to be installed on. <FIG> schematically depict projectile <NUM> showing a protective sleeve in a frontal and rear position, respectively, according to embodiments of the invention. Projectile <NUM> may have projectile body <NUM>, a war head comprised of a frontal part <NUM> and rear part <NUM> and a protective sleeve <NUM>. The warhead shown here is a guiding head and front part <NUM> is adapted to spin with respect to back part <NUM>.

In other embodiments, the shape of the warhead is such that when it is installed on the projectile frontend it creates, at the plane were the warhead meets the projectile, an external profile with deteriorated aerodynamic feature, due to sharp change in the envelope shape.

Reference is made to <FIG>, which schematically depict two different configurations of cannon shell and projectile - projectiles <NUM>, <NUM> with projectile body 6000A, 6002A respectively and projectile warhead 6000B, 6002B, respectively. Projectiles <NUM> and <NUM> may have outer diameter DPR of the projectile front part and may have outer diameter DWH of the projectile warhead, where DWH>DPR. In such configurations the sharp change of the outer profile, where warhead 600B, 6002B is attached to projectile body 600A, 6002A (respectively), causes aerodynamic disturbances, for example in the form of turbulences 6002C, that in turn consume energy from the fired projectile in flight, and may cause instability to its flight - both are undesired phenomena. There is a need to reduce the undesired effect of the sharp change in the projectile's profile. According to embodiments of the invention a slidable sleeve may be disposed proximal to the plane where the projectile warhead is attached to the projectile body, in a way that will enable to position the sleeve over the area of the sharp change- also named herein after the target position, so that the sleeve actually smooths the sharp change and improves the aerodynamic profile at that location. According to embodiments of the invention the sleeve may be positioned initially at a location distal from the target location and may be positioned at later stage in the target position.

Refence is made now to <FIG>, which schematically illustrate partial view of a front part of a projectile <NUM>, in pre-firing position and in after firing position, respectively, according to embodiments of the present invention. Projectile <NUM> is a comprises projectile body <NUM> (shown only at its frontal portion) with a front end shaped as a cone with its narrower diameter is at the front most end, and warhead <NUM> which comprises guiding unit comprised of rear part <NUM> and front part <NUM> which is rotatably connected to rear part 612by bearing assembly <NUM>. Front part <NUM> is adapted to rotate with respect to projectile body <NUM> and rear part <NUM>, for example due to the aerodynamic forces acting on the fins of front part <NUM> when the projectile is in flight. In some embodiments the outer diameter 600B of rear part <NUM> of warhead <NUM> is bigger than the outer diameter 600A of the front part of projectile body <NUM>. As discussed above the sharp change of the projectile's profile <NUM>, where rear part <NUM> of warhead <NUM> is attached to front end of projectile body <NUM> produces undesired turbulences.

According to embodiments of the invention protective sleeve <NUM> may be disposed over the rear end of warhead <NUM> such that when it is in its frontal position, as depicted in <FIG>, it covers the bearing assembly <NUM> and remains detached from front end of projectile body <NUM>. After firing of projectile <NUM>, protective sleeve <NUM> slides backwards due to, for example, the extremely high acceleration force during the firing. As a result, sleeve <NUM> slides off front part <NUM> of warhead <NUM> and may find rest where its rear end reaches location 680A on front end of projectile body <NUM>, where the diameter of projectile body <NUM> fits diameter 600C of the rear end of protective sleeve <NUM>. The distance between the front end of projectile body <NUM> and location 680A is defined <NUM>BL. Thus, protective sleeve <NUM> extends, after firing, from rear end <NUM> of warhead <NUM> to location 680A on front end of projectile body <NUM>, thereby covers the location of sharp change <NUM> and smooths the aerodynamic profile there. While sleeve <NUM> in <FIG> is presented having a substantially annular cut-off cone shape, it would be apparent that in accordance with embodiments of the invention sleeve <NUM> may have different shapes, as long as its front end smoothly fits the outer diameter 600B of rear end <NUM> of warhead <NUM>, and its rear end smoothly fits the diameter of projectile body <NUM> at location 680A. For example, the sideline of sleeve <NUM> may differ from a straight line and may be shaped as a slight curve - as may be dictated by respective aerodynamic considerations. protective sleeve may have a length <NUM>L between its front and rear end.

The embodiment presented above, with regard to <FIG>, may be useful for projectile with a rotating warhead, such as warhead with guiding assembly. In other embodiments the warhead may have an outer diameter larger than the outer diameter of the front end of the projectile but without a guiding assembly, or in any event without a rotating front end of the warhead. In such embodiments there is no need to protect the bearing assembly prior to the firing and thus - no need to provide a sliding back sleeve in response to the firing acceleration forces.

Refence is made now to <FIG>, which are schematic illustrations of projectile <NUM> (only front end is shown) in initial state and final state of installation of warhead, respectively, according to embodiments of the invention. Warhead <NUM> may be any installable warhead adapted to be screwed (or otherwise be tightly installed onto projectile body <NUM>). Warhead <NUM> may have an outer diameter larger than that of the front end of projectile body <NUM>, thereby creating a sharp change <NUM> in the aerodynamic profile of projectile <NUM>, similarly to the situation explained with respect to <FIG>. Protective sleeve <NUM> may be installed onto the outer face of warhead <NUM> in a way the will enable a user to slide it backwardly (with respect to the firing direction) either manually or with the assistance of a dedicated tool. Protective sleeve <NUM> may be provided as an integral part of warhead <NUM>, or may be provided as an add-on part, adapted to fit onto a selected warhead type. During the pre-firing stow period protective sleeve may be kept apart from warhead <NUM> or installed on it, as it may fit logistical and operational considerations. Prior to installation of the warhead onto the projectile body protective sleeve <NUM> should be placed on warhead <NUM> so that it is closer to its front end than to its rear end. After warhead <NUM> has been tightly attached to projectile body <NUM>, protective sleeve <NUM> may be slid backwardly manually, or with the assistance of a dedicated tool. Protective sleeve <NUM> should be slid backwardly until it reaches location on projectile body <NUM> where it tightly surrounds its circumference (at location analogous to location 680A of <FIG>). While sleeve <NUM> in <FIG> is presented having a substantially cone shape, it would be apparent that in accordance with embodiments of the invention sleeve <NUM> may have different shapes, as long as its front end smoothly fits the outer diameter of rear end of warhead <NUM>, and its rear end smoothly fits the diameter of projectile body <NUM> at location 680A. For example, the sideline of sleeve <NUM> may differ from a straight line (as is the case in a cone) and may be shaped as a slight curve - as may be dictated by respective aerodynamic considerations. In the case where the attachment of the warhead to the projectile body is done by means of a thread, the warhead may be threaded onto the projectile body while the protective sleeve is in its forward position (see <FIG>) and only after the warhead has been securely attached to the projectile body, the protective sleeve may be slid backwardly to its rear position, thereby forming an aerodynamic cover to the point of sharp change in the aerodynamic profile.

Claim 1:
A device (<NUM>) for sealing a projectile guiding kit (<NUM>) having a rear unit (<NUM>) adapted to be connected at its rear end to a front end of a projectile (<NUM>) and a front unit (<NUM>) rotatably connectable at its rear end to a front end of the rear unit, the device comprising:
an annular body (<NUM>) adapted to envelope at least a front portion of the rear unit and at least a rear portion of the front unit of the guiding kit; and
a flexible ring-shaped strip (<NUM>) attached to an inner side and close to a front end of the annular body, the ring-shaped strip is adapted to seal a gap (<NUM>) between the rear unit and the front unit of the guiding kit at a connection region therebetween;
wherein the annular body (<NUM>) is adapted to slide towards the rear unit (<NUM>) of the guiding kit when subjected to a longitudinal acceleration that exceeds a predetermined acceleration value, thereby uncovering the gap (<NUM>) and enabling uninterrupted rotation of the front unit with respect to the rear unit of the guiding kit.