Patent Application
20080020355
While embodiments of this invention can take many different forms, specific embodiments thereof are shown in the drawings and will be described herein in detail with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention, as well as the best mode of practicing same, and is not intended to limit the invention to the specific embodiment illustrated.
In a disclosed embodiment, a visible laser beam, co-aligned with a MILES-type laser beam, is built into a small arms transmitter (SAT) so that a user can effectively see where the MILES-type beam is incident. The visible laser can be a laser diode emitting in the red region of the visible spectrum. Other-color laser diodes may be used instead of red, but red laser diodes are adequately visible for this application.
The user aims his/her weapon, using his/her normal sights, at a point on an easily-visible stationary target sufficiently distant so that the parallax introduced by the fact that the laser beams are not laterally co-located with the gun sight axis, is not significant. At 100 meters the parallax error is a few tenths of an mrad, which is smaller than the error in most boresighting operations.
One of the common retro-reflective, self-adhesive tapes can be attached to the target to enhance the visible-laser visibility. The SAT is then adjusted until the visible laser beam strikes the same point. The MILES laser beam, emitted by the SAT, which was previously co-aligned with the visible laser beam, is therefore boresighted to the weapon's sights.
In another aspect of the invention, the two laser diodes, along with their collimating lenses, are mounted in a SAT optics sub-assembly. At the time of manufacture the sub assembly frame is mounted on a precision fixture that simulates the angular orientation of the sub assembly when mounted in the SAT, with respect to the weapon-barrel angular orientation. The MILES laser diode is positioned so that the beam characteristics and angular direction are correct, and then cemented in place. The visible-laser diode is similarly positioned and adjusted so that its beam is collinear with the MILES laser beam. It is then also cemented in place. At this point in the procedure the two laser beams are aligned permanently parallel to one another and therefore boresighted to each other.
In yet another aspect of the invention, the optics sub-assembly is next installed into the SAT. In a disclosed embodiment, the sub-assembly is attached to the frame of the SAT by a ball joint, which will allow rotation in the two orthogonal directions while not allowing translation.
The sub assembly can be rotated about two orthogonal axes perpendicular to the optical axis of the MILES laser beam by two adjustment screws. In this way the two co-aligned laser beams are angularly moved with respect to the barrel of the weapon for boresighting to the angular orientation of the barrel.
In known SATs the boresight angular adjustment range is about +/−8 mrad, which has proven adequate. Collimating lenses having a focal length on the order of 15 mm can be included. Hence, the overall length of the SAT optics sub-assembly can be about 20 mm. A +/−8 mrad adjustment range translates into about 6 mils of translation at the location of manually operable adjustment screws.
The adjustment screws can have TEFLON plastic or other low-friction elements either on the end of the screw or on a pad that the screw contacts. Another approach is to include a flexible joint in each linkage between the adjustment screws and the laser assembly. Something of this nature is preferred because of the slight motion of the SAT optics sub-assembly transverse to one screw symmetry axis when the orthogonal screw is adjusted. The fine-thread adjustment screws can be configured to work against stiff springs to eliminate backlash, and to retain the boresight adjustment during blank firing and rough handling of the gun. Linear adjustments could be used as an alternate.
A protective window can be incorporated in the SAT. It provides an environmental seal because the SAT optics sub-assembly will move during the boresight adjustment.
In yet another aspect of the invention, it would be desirable if the beams for the MILES laser and the visible, boresighting laser passed through common SAT optics. For example and without limitation, a beam splitter could be used to fold the visible beam into coincidence with the MILES beam. Both beams could then be directed through a common collimating lens prior to exiting the SAT transmitter. The beams can be adjusted by laterally displacing the collimating lens using a simple two dimensional positioning device.
SAT 12 emits an infrared MILES beam, invisible to the human eye, 20 and a visible boresighting beam 24. Both beams 20, 24 exit the SAT 12 displaced and parallel to one another.
It will be understood that the SAT 12 includes a housing or a frame 26 which incorporates the sources of the beams 20, 24 as well as any other appropriate optics. As described subsequently, the beams 20, 24 can be adjusted in unison for boresighting purposes.
Each of the sources 20-1, 24-1 is located at a focal point of a respective collimating lens 20-2 and 24-2. Radiant energy which passes through the respective collimating lens 20-2, 24-2 is emitted from the frame or housing 26 as a respective beam 20, 24.
The housing 26 also carries a protective optically transparent window 36 to protect the sub-assembly 30 from external environmental conditions. Those of skill will understand that the window 36 could be formed of selected glass or plastic.
As illustrated in
Using the adjustment elements 38-1, 38-2 the user can then aim the weapon using its normal sights at a point on an easily-visible stationary target. The target is selected such that it is sufficiently distant that any parallax introduced by the fact that the two beams 20, 24 are not laterally co-located with the sights of the weapon is insignificant.
The sub-assembly 30 can then be adjusted using adjusting elements 38-1, 38-2 so that the visible beam 24 is incident on the same point at which the weapon is being aimed using its normal sights. The MILES beam 20 emitted by source 20-1 was previously co-aligned with the visible beam 24. It is as a result boresighted to the weapon's sights.
For purposes of providing a stable orientation and adjustment of the sub-assembly 30, a spring 40, or other friction inducing element, can be associated with each of the adjustment elements 38-1, 38-2. Those of skill will understand that the housing or frame 26 of the SAT can be formed of metal, plastic or the like all without limitation.
An adjusting element such as element 62 can be used to laterally deflect the lens 56. An orthogonal adjustment screw, not shown, can be used to laterally deflect the lens in the orthogonal direction so that these two lens deflection directions will steer the two coincident beams to align them to the weapon sight axis. It will be understood that other adjusting elements and configurations to achieve the desired coextensive emission of the beams could be used without departing from the spirit and scope of the present invention.
From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.
