IL138987A - Boresight for gun - Google Patents

Description

nmni> tup Julia Boresight for gun Dimitry Zwilinsky >pv m »WWr C. 126209 FIELD OF THE INVENTION The present invention is in the field of firearm barrel boresighting devices and more specifically it is concerned with a boresighting device which is operated from a breech end of the barrel.

BACKGROUND OF THE INVENTION Boresighting is the process of aligning a gun's barrel with the gun's sights by sighting a distant point through the barrel's bore and adjusting the sights to the same point. However, the line of sight of the bore requires collimating first to obtain the correct optical line of sight through the bore. This procedure is referred to as "boresighting" and a device for carrying out the procedure is known as a boresighting device.

According to one technique, a boresighting device is inserted into the muzzle end of a barrel, whereby a crew member, e.g. of a tank or a mobile gun is required to leave the armored vehicle and perform the boresighting procedure at the muzzle end of the gun. This arrangement has the serious drawback of endangering the crew member's life having to depart his armored vehicle, which may be hit by enemy forces at the combat field or may step on a mine.

It is the object of the present invention to provide a new and improved boresighting device. 138987/2 SUMMARY OF THE INVENTION According to the present invention there is provided a device for boresighting a firearm barrel, the device comprising an elongated body having a fore end and a rear end and being adapted for insertion into the barrel's bore via a breech end thereof; the device characterized in that it comprises an advancing device for advancing it through the barrel and front and rear engaging means for engaging the inner walls of the bore and fixing the device within the bore, optical means rotatable about an elongated axis of the device over at least 180° and a collimating mechanism consisting of calibration mechanism; there being provided monitor means for remotely receiving a video image viewed by said optical means.

Preferably, the advancing device of the boresighting device in accordance with the present invention is a driving mechanism and the boresighting device further comprises a sensor for signalling when the foreend of the device has reached adjacent a muzzle end of the barrel. In a specific application, said sensor is an arm swingably hinged at the fore end of the device and being spring-biased so as to laterally project, whereby when the device reaches the muzzle end of the barrel, the drive unit is stopped and the contact means engage the walls of the bore.

According to an embodiment of the invention, the boresighting device further comprises at least three rollers equi-angularly displaced on the periphery of the device and slightly projecting therefrom, at least one of said three rollers comprising a drive unit. In a preferred embodiment, said driving mechanism is located adjacent a rear end of the device.

According to still a preferred embodiment of the invention, each of said rear and front engaging means consists of at least three contact surfaces, radially projecting from a peripheral surface of the device, at least one of the three contact surfaces being radially displaceable so as to pressure-engage the wall of the bore.

In a specific application of the invention, said radially displaceable contact surface is hydraulically displaceable.

In a specific embodiment the optical means is a video camera, 20 said optical means being rotatable around its longitudinal axis by a first motor and wherein said calibration mechanism consists of a second motor and a third motor for tilting a front end of the optical means in two axes perpendicular to the longitudinal axis of the optical means. In a specific application, the motors are remote controlled by cables, however they may also be controlled by a wireless remote control arrangement.

Control signals and power are supplied to the boresighting device via a cable extending from a rear end of the device. However, according to a specific application of the invention, the device may be provided with integral power means and wherein control signals and video signals may be transferred by wireless 0 means.

BRIEF DESCRIPTION OF THE DRAWINGS In order to understand the invention and to see how it may be carried out in practice, a preferred embodiment will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: Fig. 1 is a longitudinal view of the boresight device according to the present invention, partially sectioned; Fig. 2 is a cross-section taken along line 11-11 in Fig. 1, showing the driving mechanism; Fig. 3 is a longitudinal section along Ill-Ill in Fig. 1, showing the engaging o means; Fig. 4 is a longitudinal section along line IV-IV in Fig. 1, illustrating the optical means; and Fig. 5 is a schematic cross-sectional illustration showing a barrel's bore with the boresighting device accommodated therein.

DETAILED DESCRIPTION OF A SPECIFIC EMBODIMENT Reference is first made to Figs. 1 to 4 in which a boresighting device 2 has an elongated, cylindrical body portion 4 made of a light metal and comprising a plurality of openings 6.

At a fore end of the device there is an enlarged portion 8 having a diameter larger than that of the body portion 4 and at the rear end of the device there is an enlarged portion 10 having a diameter similar to that of the fore end portion 8, the diameter being slightly smaller than the diameter of the bore of the barrel (seen in Fig. 5).

As can better be seen in Fig. 2 of the drawings, the rear portion 10 comprises a drive mechanism, generally designated 12 and consisting of three equi-angularly displaced rollers 14 and 16, of similar diameters, the rollers being embedded within housings 18 and projecting through openings 19 at the rear portion 10 (see Fig. 1), each housing 18 comprising a coiled spring 20 for biasing the rollers in a radial direction. Roller 16 is linked to an electric motor 22 receiving its power supply via power cable 25 extending from the rear end of the boresighting device 2.

Engaging means 28 (seen in cross-section in Fig. 3) consists of two fixed contact pads 30 slightly projecting from the external surface of the rear and front portions 8 and 10, respectively and a retractable pressure pad 32 attached to an hydraulic piston 34 for imparting radial displacement thereto. The hydraulic piston 34 is coupled to an hydraulic power unit 36 (seen in Fig. 1) for supplying hydraulic pressure, as known per se.

It should be obvious to a skilled person that the rollers 14 and 16 of the driving mechanism 12 and the pads 30 and 32 of the engaging means 28, are adapted for engagement with the inner wall of a specific bore of a barrel. For barrels of different nominal calibers, different boresighting devices may be required, or there should be provided suitable fore and rear end adapters.

The optical means used in conjunction with the invention, is typically a video camera 40 pivotally accommodated within a housing 41 rotatably articulated adjacent its rear end by links 42 to the inner wall of the body portion 4. The video camera 40 is coupled to a first motor 44 adapted for rotating the camera 40 around the longitudinal axis 46. A second motor 48 is responsive for tilting the front end 138987/2 of camera 40 in a vertical direction and a third motor 50 is responsive for tilting the front end of video camera 40 in an essentially horizontal direction. A communication cable 49 extending from the rear end of the device transmits the video signal to a monitor as will hereinafter be explained and the motors 44, 48 and 50 receive power via cable 25.

A sensor member 51 is hinged at 52 to the front end portion 8.

The sensor is biased by spring 54 as to radially project as illustrated by dashed lines. As the boresight is advanced through the barrel, the sensor 51 is pushed by the inner wall of the bore to the position illustrated by the solid line. However, when the device reaches the muzzle end of the barrel, the sensor 51 springs into the position illustrated by the dashed line, whereby it activates a micro-switch (not shown) yielding a control signal to instantaneously terminate operation of the driving motor 22 and activate the engaging mechanism 28 as to fix the device within the bore.

Attention is now directed to Fig. 5 of the drawings for better understanding of the operation of the device. In operation, the boresighting device 2 is inserted into the breech end 60 of the barrel 62 as illustrated by 2' and then, the electric motor 22 of the driving mechanism 12 is activated, whereby the boresighting device 2 is propelled forward within the bore 64 of the barrel, paying out the power cable 25 and the communication cable 49 from the rear end thereof. As soon as the device 2 reaches the muzzle end 66 of the barrel 62, the stop sensor 51 projects from the muzzle and is allowed to snap into its biased position (illustrated by dashed lines in Fig. 1), wherein the micro-switch (not shown) is activated and a control signal is transmitted, whereby the driving motor 22 is instantaneously stopped and simultaneously, the hydraulic engaging pads 32 expand so as to engage the walls of the bore 64.

Then, the collimating process takes place as known per se, wherein a remote object is viewed by the video camera 40, the image being transmitted via communication cable 49 to a monitor (not shown) positioned at the operator's end, adjacent the sights 68 of the barrel. Then, the camera 40 is rotated around the 138987/2 longitudinal axis 46 at 180°. and the object is viewed again. If the object does not fall within the line of view, the camera is calibrated by motors 48 and 50 controlled via power cable 25, tilting the camera in axes perpendicular to the longitudinal axis 46. The process is repeated until the viewed object falls within the line of sight of the bore at both angular positions of the camera.

After completion of the calibration procedure as above, the external sight 68 of the gun is calibrated as known per se, so as to have in sight the same objected viewed by the camera 40 whereby the device is removed and the gun is ready for use.

After completion of the boresighting process, the engaging pads 32 are disengaged from the bore walls 64 and the driving motor 22 is activated in a reverse direction so as to return the device 2 to the breech end 60 of the barrel 62.

It should be obvious to a person versed in the art that, although the invention is described with reference to a video camera, other optical means may be used, e.g. an IR camera, a laser sight, thermal cameras, etc.

It should also be obvious that various control means may be used for controlling the operation of the boresighting device, such as wireless remote controls, etc. It should also be understood that the advancing means may be any suitable arrangement for advancing the boresighting device from the breech end to the muzzle end of the barrel e.g, pneumatic propelling means etc. Furthermore, at least one of the rollers of the driving mechanism constituting the advancing device comprises means for radially biasing it against the walls of the barrel. Such means may be for example a biasing spring or a hydraulic piston.

Claims (11)

138987/2 CLAIMS:

1. A device for boresighting a firearm barrel, the device comprising an elongate body having a fore end and a rear end and being adapted for insertion into the barrel's bore via a breech end thereof; the device characterized in that it comprises a driving mechanisrfr for advancing the device through the barrel, front and rear engaging means for engaging the inner walls of the bore and fixing the device within the bore, optical means rotatable within the device over 180° and an associated calibration mechanisiri and monitoring means for remotely receiving a video image viewed by said optical means.

2. A boresighting device according to Claim 1, wherein a sensor is provided for signalling when the fore end of the device has reached adjacent a muzzle end of the barrel.

3. A boresighting device according to Claim 1, wherein said driving mechanism comprises at least three rollers equi-angularly displaced over the periphery of the device and being adapted for engaging the bore's wall, at least one of said three rollers comprising a drive unit.

4. A boresighting device according to Claim 3, wherein said driving mechanism is located adjacent a rear end of the device.

5. A boresighting device according to Claim 1, wherein each of said rear and front engaging means consists of at least three contact surfaces radially projecting from peripheral surfaces of the device, at least one of the three contact surfaces being radially displaceable so as to pressure engage the wall of the bore.

6. A boresighting device according to Claim 5, wherein said radially displaceable contact surface is hydraulically displaceable.

7. A boresighting device according to Claim 2, wherein said sensor is an optical sensor.

8. A boresighting device according to Claim 2, wherein said sensor is an arm swingably hinged at the fore end of the device and being spring-5 biased so as to laterally project, whereby when the device reaches the muzzle end of the barrel, the drive unit of the drive mechanism is stopped and the contact means engage the wall of the bore.

9. A boresighting device according to Claim 1, wherein said optical means is a video camera.

10. A boresighting device according to Claim 1, wherein said optical means is rotatable around the longitudinal axis by a first motor, wherein said calibration mechanism consists of a second motor and at third motor for tilting a front end of the optical means in two axes perpendicular to the longitudinal axis of the optical means.

11. A boresighting device according to Claim 1, wherein said at least three rollers are radially biased. For the Applicants, J:\01262096\01262096_0000 l_SPC.doc DD/be- 11/10/2000