Patent Publication Number: US-6216381-B1

Title: Laser device for use in adjusting a firearm&#39;s sight and a method for aligning a laser module

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to devices and techniques for accurately positioning the sight of a firearm, and more particularly deals with in-bore laser devices and methods of using such devices to improve the positioning accuracy of a firearm&#39;s sight. 
     Use of sights for aiming firearms, such as rifles and pistols, is well known. Ideally, when a firearm&#39;s scope is properly adjusted, the projectile shot from the firearm will strike the target at a known position identified through visual alignment with a feature of the scope, such as the intersection of scope cross-hairs. Understandably then, those with skill in the art desire efficient techniques for accurately positioning a firearm&#39;s sight. 
     U.S. Pat. No. 5,787,631 (“&#39;631 patent”) issued to Kendall discloses an array of prior techniques for use in aligning firearm sights. For example, the &#39;631 patent discloses a technique in which a series of rounds are shot at a target, each followed by comparison between the anticipated target spot as viewed through the sight and the corresponding actual striking location for the given round. The comparisons were used to refine the position of the firearm sight. Presumably, this “trial and error” approach is time consuming, and wastes ammunition. 
     The &#39;631 patent also discloses a group of laser-based techniques for aligning a firearm sight, and in particular, focuses on U.S. Pat. No. 5,365,669 (“&#39;669 patent”) issued to Rustick et al. The &#39;631 patent identifies a problem with the &#39;699 patent approach, and proposes a solution therefor. Specifically, one of the main problems associated with the &#39;699 patent was that the laser beam emitted from the laser module would likely fail to clear the bore of the rifle, unless suitable laser alignment was provided. 
     In response, the &#39;631 patent proposed using set screws to facilitate laser module alignment. Specifically, the &#39;631 patent disclosed a housing including a threadedly engaged inner sleeve, which contains a laser module and a battery. Four set screws penetrate the housing to facilitate movement of the laser module, presumably into a properly aligned position. Additionally, the &#39;631 patent discloses the use of a springbased switch mechanism to operate the laser module. Specifically, when the &#39;631 device is inserted into a firearm and the firearm&#39;s bolt is engaged, the force of the bolt closes the switch mechanism to activate the laser module. 
     Though the &#39;631 patent asserts to have overcome certain shortcomings of the prior art, it too has limitations. For example, using four set screws to align the laser module is a cumbersome and time consuming task. Each time the user makes an adjustment, one set screw is tightened, and an opposing set screw must be loosened to permit free motion for the laser module. Moreover, with each adjustment of the laser module, the user has to evaluate its effectiveness in planning the next adjustment. The process is inherently complex, as it involves coordinated adjustments along multiple axes of motion for the laser module. 
     Another problem affiliated with the &#39;631 patent resides in the switch mechanism. Pressing the switch  8  at that back of the &#39;631 device energizes the laser module. This can be carried out when the device is loaded into a firearm, as desired, due to the force of the firearm&#39;s engaged bolt. Similarly, the laser module can be activated when the &#39;631 device is out of the firearm, as pressing switch  8  energizes the laser module regardless of whether the device is or is not located within the firearm. Thus, a user can prematurely drain the device&#39;s battery by inadvertently closing switch  8  by, for example, putting the device in a coat pocket. Switch  8  poses yet another problem, namely, that it incorporates movable components subject to eventual inoperability due to normal wear and tear. 
     There therefore was a need for an improved laser device for use in adjusting a firearm&#39;s sight, and a method for aligning a laser module that overcome the limitations of prior devices and techniques. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention concerns a device facilitating adjustment of a sight of a firearm by providing a visible mark on a target when the device is placed within a chamber of the firearm. The device may include: a laser module energizeable within the chamber to produce the mark at a position along a laser axis; a power supply situated within the chamber to energize the laser module when an electrically conductive flowpath is completed with the laser module; and an electrical circuit including a conductive part of the firearm through which electrical current flows to complete the flowpath. 
     In this manner, inadvertent operation of the device is averted, as part of the conductive flowpath for energizing the laser module is a portion of the firearm. To further this end, a non-conductive cover or a carrier with an appropriately situated non-conductive region may be used to prevent unintentional operation when the device is outside the firearm. 
     Similarly, a method is disclosed which prevents unintentional operation of the device. The method involves positioning the laser module within a chamber of a firearm; and adjusting the firearm to complete an electrical circuit between a power supply and the laser module, wherein part of the firearm conducts current in between the power supply and the laser module. 
     The device may also include a housing having an internal cavity, which restricts the laser module&#39;s range of motion to rotation of the module about a laser axis, and a sweeping motion of the module defining a locus of points along the laser axis which comprises a single plane. The range of motion restriction on the laser module facilitates a more simplified alignment process for the laser module, whether it be used to calibrate a gun sight or not. 
     The method of aligning a laser module having a laser axis involves: providing a housing including an internal cavity; inserting the laser module into the internal cavity, which restricts the laser module&#39;s range of motion to rotation of the module about the laser axis, and a sweeping motion of the module defining a locus of points along the laser axis which comprises a single plane; supporting the housing containing the laser module; energizing the laser module to produce a mark on a target; holding the housing in place while rotating the laser module about the laser axis until the mark strikes an axis on the target that is coplanar with the single plane; and moving the laser module until the mark strikes a desired position. 
     The and other objects, advantages and aspects of the invention will become apparent from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown a preferred embodiment of the invention. Such embodiment does not necessarily represent the full scope of the invention and reference is made therefor, to the claims herein for interpreting the scope of the invention. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a partially exploded perspective view with parts broken away from a laser module for use in the device of FIG. 2; 
     FIG. 2 is a diametric cross-sectional view of the device of the present invention; 
     FIG. 3 is a view taken along line  3 — 3  of FIG. 2, but showing the device in full cross-section; 
     FIG. 4 is a partial plan view of the device of the present invention; 
     FIG. 5 is a perspective view of the device of the present invention resting in a support, and emitting a laser beam against a target for use in aligning the laser module; 
     FIG. 6 is a plan view showing a pattern of laser beam contact against the target for use in aligning the laser module; 
     FIG. 7 is a partial perspective view of a firearm and scope with portions broken away to show the device of FIG. 2; and 
     FIG. 8 is a simplified cross-sectional view of the device with an outer sleeve for adjusting the device&#39;s outer dimensions to match those required by the firearm. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, wherein like reference characters represent corresponding elements throughout the several views, and more specifically referring to FIG. 7, device  10  of the present invention is shown within firearm  44 . 
     Firearm  44  is shown in the “locked and loaded” condition, a state well known to those skilled in the art. Portions of FIG. 7 are shown broken away to reveal firearm internals including a bolt head  48 , a firing pin  50 , and a barrel  52 . Device  10  is situated within a chamber of firearm  44  where a round typically resides prior to firing, though device  10  cannot be fired. Additionally, one of several reserve rounds  54  is also shown, but typically no actual rounds  54  are loaded when device  10  is being used to facilitate sight adjustment. 
     Here, firearm  44  is a rifle, though those skilled in the art understand that device and its associated methodology could be used with any type of firearm including a rifle, a hand gun, a machine gun, or the like. Similarly, firearm  44  includes a scope  46 , but those skilled in the art understand the device  10  and the related methodology could be used with any type of firearm scope, sight, or the like. 
     Referring to FIG. 2, device  10  includes housing  12  containing laser module  14  and power supply  16 . The external shape of device  10  resembles the external shape of round  54  (see FIG.  7 ), though unlike round  54 , device  10  does not contain a bullet. More generally, the external shape of device  10  will resemble the external shape of a round of appropriate caliber for shooting from the firearm, whatever be the caliber and type of the firearm, though device  10  typically will not include a bullet. 
     By way of example, the external configuration of housing  12  comprises various sections from front to back. A front tubular section extends from front opening  12   a  to position  12   b . From position  12   b  to a location in between locations  12   b  and  12   c , the outer diameter of housing  12  increases providing a conically-shaped section. At a point in between locations  12   b  and  12   c , the increase in outer diameter of the conically-shaped section stops, and a tubular section having a very slight (not visible in FIG. 2) increase in outer diameter extends to the back end  12   d  of housing  12 . 
     Front-end opening  12   a  permits laser beam passage, while the opposite end of housing  12  also includes an opening, typically closed when device  10  is assembled. More specifically, a back-end insulator  20  is threadedly engaged with housing  12 . Back-end insulator  20  is tubular and includes a central cavity with internal threads for receiving back-end cap  22 , which has a T-shaped cross-section. The shaft of back-end cap  22  includes a recess for receiving a spring  24 , which makes contact with power supply  16  when device  10  is assembled. 
     Housing  12 , back-end insulator  20 , and back-end cap  22  are each manufactured using well known techniques. The material used to make housing  12  and back-end cap  22  is brass, or any other rigid conductive material; however, back-end insulator  20  is made with a rigid material that is, at least in part, non-conductive. For example, back-end insulator  20  may be entirely made from non-conductive material, like plastic. Alternatively, back-end insulator  20  may be made from a conductive material, such as aluminum, with an outer layer completely anodized using a non-conductive material. In yet another alternative, insulator  20  may be made with a conductive material having selected outer surface portions anodized with non-conductive material. 
     In sum, housing  12 , back-end cap  22 , and spring  24  are conductive, while backend insulator  20  (or at least selected outer surface portions thereof) is non-conductive. Accordingly, an open circuit is established by back-end insulator  20 , regardless of its manner of construction, in the electrical flowpath in between power supply  16  and housing  12 . 
     Power supply  16  comprises one or more batteries providing sufficient power to operate laser module  14 . Presently, a series pair of button batteries is used providing a combined voltage of 3.0-4.5 volts, though any one of a number of well known power supplies may be used. Moreover, if a different laser module  14  were used (having different power needs), then alternative power supply arrangements may be used. 
     Power supply  16  makes electrical contact with springs  24  and  26 . Specifically, the negative electrode of power supply  16  contacts spring  26 , in electric communication with laser module  14 , and the positive electrode of power supply  16  contacts spring  24 , in electric communication with back-end cap  22 . However, backend insulator  20  prevents completion of the flowpath from back-end cap  22  to housing  12 , which is in electric communication with laser module  14 . Thus, laser module  14  does not operate until an electrically conductive flowpath is established in between back-end cap  22  and housing  12 . 
     When power supply  16  (e.g., button batteries) does not include its own outer insulating layer, insulator  18  is included. This prevents power supply  16  from making direct electrical contact with the interior surface of housing  12  or with laser module  14  (other than through spring  26 ), which would activate laser module  14 . Insulator  18  includes a tubular section, which electrically isolates power supply  16  from the interior surface of housing  12 , and a lip inserted in between power supply  16  and laser module  14  for similar purpose. Insulator  18  may be made from plastic or any other rigid insulating material. 
     The transitional region of insulator  18 , between its tubular section and lip, rests against a mechanical stop provided by an inner surface of housing  12  which begins to taper inward at location  12   c . The mechanical stop prevents contact in between power supply  16  and laser module  14 , other than through spring  26 . If power supply  16  is itself provided with an outer insulating layer, then use of insulator  18  for electrical isolation would be redundant. 
     In between locations  12   c  and  12   b , the inner diameter of housing  12  is tapered. Moreover, the inner diameter of housing  12  at location  12   b  is such that it provides another mechanical stop, this one for the front edge of laser module  14 . FIG. 3 shows how laser module  14  resides within an internal cavity of housing  12 . Specifically, opposing outer surfaces of laser module  14  make contact with opposing interior surfaces of housing  12 . A cross section of the cavity in FIG. 3 containing laser module  14  is generally elliptical, permitting substantially one axis of motion for laser module  14  within housing  12 , namely up and down as viewed in FIG.  3 . An aperture  38  is provided through housing  12  permitting access to laser module  14 . 
     Referring to FIG. 1, laser module  14  comprises lens holder  28 , collimating lens  30 , housing  32 , laser diode  34 , and laser diode driver circuit  36 . Lens holder  28  has a generally tubular external shape with a threaded surface. A lip  28   b  is provided on an interior surface of lens holder  28  against which collimating lens  30  rests. A pair of opposing notches  28   a  are provided in a front portion of lens holder  28  for screwing lens holder  28  into matching internal threads of laser module housing  32 . Any conventional technique may be used to make lens holder  28  from any rigid material such as brass, steel, plastic, and aluminum. Collimating lens  30  is a commercially available 4 mm diameter plastic lens, though the size of and material used for collimating lens  30  may be altered, if desired. 
     Laser module housing  32  has a generally tubular external shape, and an internally threaded recess for receiving lens holder  28 . Laser module housing  32  also includes a mechanical stop  32   a  for laser diode  34 . Laser module housing  32  also includes a pair of opposing notches  32   b  for moving the laser module  14  during alignment Any conventional technique may be used to make laser module housing  32  using any rigid conductive material such as brass. Any commercially available laser diode  34  and driver circuit  36  may be used. 
     In FIG. 8, an outer sleeve  56  is shown coupled to device  10 . The purpose of outer sleeve  56  is to expand the effective outer dimensions of device  10  such that it may be used with firearms using a round of larger caliber than that for device  10  without the inclusion of outer sleeve  56 . Regardless of whether or not outer sleeve  56  is used, the structure and operation of device  10  is as described herein, though outer sleeve  56  is made with a conductive material, such as brass. 
     Assembly of laser module  14  involves inserting collimating lens  30  into lens holder  28  such that the front edge of lens  30  abuts the interior surface of lip  28   b . Collimating lens  30  is attached using any commercially available adhesive or adhering technique, such as press fitting. The laser diode  34 , driver circuit  36 , and spring  26  are typically prefabricated into a combined unit by the manufacturer. The combined unit is inserted and attached to the interior surface of the laser module housing  32  using a commercially available conductive adhesive, taking care to abut the laser diode  34  against mechanical stop  32   a . The lens holder  28  (and collimating lens  30 ) are then screwed into the laser module housing  32 , making use of the notches  28   a . The laser diode  34  is energized and the lens holder  28  rotated to focus the laser beam in a well known manner. With the laser module  14  assembled and focused, it may be filled with a commercially available non-conductive epoxy. 
     In order to align laser module  14 , a target  42  is set up at a desired distance (e.g., 100-200 feet) from support  40 , as shown in FIG.  5 . Target  42  includes a visible center point  42   b  (e.g., a one-inch diameter target spot) that has been pre-aligned with support  40  in a well known manner. This means that a properly focused and aligned laser module, when energized and placed in support  40 , would produce a laser beam spot within the desired visible center point  42   b  of target  42 . 
     Now, housing  12  is secured in place on support  40  using a clamp, one&#39;s own hands, or any other suitable technique such that aperture  38  faces upward, as shown in FIG.  5 . The housing&#39;s internal cavity is positioned such that when it receives laser module  14 , the laser module&#39;s range of motion is restricted to two possibilities. First, laser module  14  may be rotated about its own axis (i.e., axial rotation about the laser beam). Second, laser module  14  may be swept in a linear motion, which defines a locus of points along the laser beam axis comprising a single plane. The sweeping linear motion of laser module  14  is depicted in the phantom line portions of FIGS. 2 and 4. With housing  12  secured, as noted above, this single plane is substantially coplanar with the horizontal axis  42   a  depicted on target  42  in FIG.  5 . 
     Laser module  14  is inserted into housing  12  until its front edge abuts location  12   b , as depicted in FIGS. 2 and 5. Laser module  14  is energized using conventional techniques. A tool, inserted into notches  32   b  in the back-end of laser module housing  32 , is used to rotate housing  32 . As represented in FIG. 6, this causes a laser beam spot to hit target  42  and rotate as housing  32  rotates. When the laser beam spot intersects the horizontal axis  42   a  on target  42 , rotation of laser module housing  32  is stopped. Still with reference to FIG. 6, laser module housing  32  is then moved (within the confines of the internal cavity of housing  12 ) in a linear sweeping motion until the laser beam spot intersects with the center  42   b  of target  42 , indicating that laser module  14  is in the desired, aligned position. 
     An adhesive is applied to fix laser module  14  in the desired, aligned position. The adhesive may be applied through aperture  38  or through the back-end opening of housing  12 . One or more spot welds may alternatively or additionally be implemented to fix the position of laser module  14  relative to housing  12 . Also, an epoxy may be used to fill the void in between laser module  14  and the interior surface of housing  12 . 
     To complete assembly of device  10 , insulator  18  is inserted through the back-end opening in housing  12 , and power supply  16  is likewise inserted. Back-end insulator  20  is screwed in place, as is back-end cap  22  with its associated spring  24 . If a firearm  44  of caliber larger than that corresponding to device  10  is used, then an outer sleeve  56  of appropriate dimension is attached in any conventional manner to device  10 . 
     In operation, device  10  is inserted into a chamber of firearm  44  where a round typically resides prior to firing, and firearm  44  is put into a “locked and loaded” condition. In this state, the firearm&#39;s bolt head, ejector, or like conductive parts will make physical and electrical contact in between back-end cap  22  and housing  12 , typically in proximity to location  12   d . It should be noted that certain terminology may vary from one firearm to the next. For example, the names for internal components (e.g., bolt head or ejector) and states of operability (e.g., “locked and loaded”) may be different for various firearms; however regardless of the terminology used, in some state of operation a conductive part of the subject firearm will make physical and electrical contact in between back-end cap  22  and housing  12 . 
     In this condition, an electrical circuit is established including a conductive part of firearm  44  through which electrical current flows to energize laser module  14 . Specifically and with reference to FIG. 2, one electrode of power supply  16  is electrically coupled through spring  26  to laser diode driver circuit  36 . The other electrode of power supply  16  is electrically coupled to spring  24 , back-end cap  22 , the conductive part or parts of firearm  44 , housing  12 , and laser module housing  32  to laser diode  34  to complete the circuit. The conductive part or parts of firearm  44  may include a bolt head, an ejector, a barrel, or any other conductive part of firearm  44 . 
     With the laser beam now emerging from a focused, aligned laser module  14 , the user may put the laser beam spot on target  42 , and then align the firearm&#39;s scope or sight  46  in a well known manner. 
     It should be understood that the methods and apparatuses described above are only exemplary and do not limit the scope of the invention, and that various modifications could be made by those skilled in the art that would fall under the scope of the invention. For example, while the method for aligning the laser module has been disclosed herein for use in aligning a firearm&#39;s scope, it is understood that the laser module alignment method is not limited to this field of use. 
     To apprise the public of the scope of this invention, the following claims are provided: