Abstract:
Block-bracing apparatus including at least three plugs threadedly engageable through a block, and retaining rings engaging the block threaded oppositely to the threaded plugs and retainably engaging the plugs. A key tool is provided to tighten the plugs and retaining rings. A longitudinally oriented T-rail projects radially from the block. A slide body engages the T-rail and includes a locking mechanism, a lamp assembly, a logically switched power control, a power cable, and a control cable with interchangeable switches.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a division of co-pending U.S. patent application Ser. No. 11/159,504 filed Jun. 22, 2005, which application is incorporated in full herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention addresses the problems encountered when attaching an accessory, such as a light beam generator or other optical apparatus, to a Browning M2 .50 caliber machine gun and then operating the accessory with the gun. 
     The Browning M2 machine gun (hereinafter “M2”), utilized by the U.S. armed forces, weighs about 35 kilograms and recoils heavily when fired. It is usually supported from beneath, sometimes by a tripod, more commonly by a post or pintle installed on a platform such as a vehicle, vessel or aircraft. If an accessory is to be aimed with the gun, it might as well be mounted on the gun. However, there is a need for a sturdy, secure way to attach an accessory to the M2. 
     The M2 has a shroud which is capable of supporting an accessory. The shroud is a substantially cylindrical cast metal shell which surrounds the gun barrel, is rigidly fixed to the body of the gun, and projects forward about 20 centimeters from the front of the body of the gun. The shroud has an outside diameter of about 8 centimeters and a shell thickness of about 0.7 centimeter. The shroud has a plurality of substantially circular perforations, about 2 cm in diameter, formed by casting or machining. As presently configured, the perforations are arranged in six sets of three. The three perforations of each set are spaced apart about 120° in a plane perpendicular to the longitudinal axis of the shroud. Successive sets of perforations are spaced apart about 1.5 cm longitudinally and offset by about 60°. 
     The shroud is an ordinary feature of many of the M2 machine guns that are in service. However, as will be discussed below in describing the present invention, there is a need in particular for a sturdy, secure way to support a growing inventory of accessories by utilizing the shroud. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to utilize the shroud of the M2 machine gun for mounting a wide range of accessories in a sturdy, secure way and, in particular, to removably secure a light beam generator or light to the shroud of the M2 and to operate the light beam generator with the M2. 
     New accessories for the M2 are evolving. Some of these accessories, which include light beam generators and the like, have a mass of several kilograms and may extend as far as 40 centimeters laterally or vertically from the gun. Sometimes difficulties are encountered in mounting and operating such accessories. The present invention addresses a source of these difficulties, namely, that recoil, vibration, maneuvers and other rough treatment may knock the accessories out of alignment, loosen them, or separate them from the gun. 
     The shroud of the M2 is rigid and sturdy and is firmly attached to the gun. In attaching heavy or bulky accessories to the shroud, new difficulties may be encountered with the shroud itself. For example, the perforations of the shroud are not precisely machined, nor are they formed in precisely the same manner, shape and location in every shroud. In some older shrouds, the perforations were bored radially. In some newer ones, the perforations are formed as the shroud is cast, and thus they extend in the direction in which the casting is pulled. The present invention solves these problems by providing a way of stably attaching bulky, massive accessories to the shroud, taking advantage of the perforations of the shroud despite its variably shaped perforations. 
     The present invention also addresses other sources of difficulty in managing accessories in combination with the gun, including the need to avoid accidentally activating the accessory, wasting power, heating up the cable, or subjecting a mechanical switch to high current while working with light emitters or lamps having high power consumption. 
     In accordance with the present invention, an exemplary embodiment of an adapter for removably securing an accessory to a machine gun having a shroud about the gun barrel has a block adapted to embrace the shroud and at least one set of three plugs adjustably securable through the block and adapted to engage the shroud. Additionally, the block may encircle the shroud. Preferably, the plugs threadedly engage the block, especially by means of ACME threads. Additionally, retaining rings may threadedly engage the block in abutting relation to the plugs, preferably by means of threads having a pitch angle opposite that of the threads of the plugs. 
     The plugs may be at least partly convex-nosed. Preferably, the plugs are blunt-nosed and have a diameter predetermined to exceed the diameter of an identified surface feature of the shroud, such as the regularly arranged perforations formed in the shroud of the M2. Preferably, the plugs are adapted for smooth spiral advance into bracing contact with a surface of a shroud. Preferably, the plugs are bored out centrally. This saves weight. 
     The plugs may include tails adapted to engage a tool. For example, the tails may have a cruciform indentation for engaging a tool having a cruciform bit. 
     The retaining rings may encircle the tails when in the abutting relation to the plugs. This saves space. The retaining rings may be adapted to engage a second tool. For example, the retaining rings may have a plurality of bores adapted to engage a tool having a plurality of pegs. 
     The three plugs of the at least one set may be angularly spaced apart and located substantially within a first plane transecting the longitudinal axis of the shroud at a first point. This helps to balance the forces exerted by the plugs about the longitudinal axis of the shroud. 
     The block itself may include at least one rail adapted for mounting an accessory. The adapter may also include at least one rail adapted for mounting an accessory, the rail being securable to the block, preferably after the plugs and the retaining rings have been engaged in the block. The rail, when secured to the block, covers at least one of the plugs and at least one of the retaining rings. This takes advantage of the compact arrangement of the plugs and retaining rings when they are engaged in the block. Because the plugs and retaining rings protrude little or not at all from the block, a rail can be secured over them without interference. 
     The adapter may include a plurality of rails adapted for mounting accessories, a first of the rails being securable to the block when the plugs and the retaining rings are engaged in the block; the rail, when secured to the block, covering at least one of the plugs and at least one of the retaining rings; a second of the rails being so located on the block as not to cover any of the plugs and retaining rings. This provides a greater variety of positions at which an accessory may be mounted. 
     Additionally, a second set of three plugs may be included, also adjustably securable through the block and adapted to engage the shroud, also angularly spaced apart, but located substantially within a second plane transecting the longitudinal axis of the shroud at a second point longitudinally spaced apart from the first point. This second set of plugs further stabilizes the block on the shroud and further distributes the loads that are transmitted between the block and the shroud. This second point may be longitudinally separated from the first point by a distance equal to a longitudinal separation between recurrences of a predetermined surface feature of the shroud. 
     Additionally, the plugs in each of the sets of plugs may be angularly spaced apart an angle equal to a predetermined angular separation between recurrences of a predetermined surface feature of the shroud. 
     Also in accordance with the present invention, block-bracing apparatus includes a block; at least three plugs, engageable through the block via threads having a first orientation, the plugs having plug tails with a first tool-engaging adaptation; and at least three retaining rings, the retaining rings being positionable in abutting relation to the plugs and in surrounding relation to the tails, the retaining rings being engageable in the block via threads oriented opposite the first orientation, the retaining rings having a second tool-engaging adaptation. A two-ended key tool is provided and is adapted alternatively to engage the first and second tool-engaging adaptation. Preferably, the key tool has a first bit including a centrally located cruciform bit and a second bit including a plurality of peripherally arranged pegs. 
     The three plugs may be angularly spaced apart and located substantially within a first plane transecting the longitudinal axis of the shroud at a first point, and the apparatus may further include a second set of three plugs, adjustably securable through the block and adapted to engage the shroud, angularly spaced apart and located substantially within a second plane transecting the longitudinal axis of the shroud at a second point longitudinally spaced apart from the first point, for enhanced stability and load distribution. 
     Also in accordance with the present invention, apparatus for controlling a light emitter includes a logical switch electrically coupled to the light emitter; a power input cable electrically connectable to the logical switch and to an electric power source; a control input cable electrically connectable to the logical switch; and at least one control input device electrically connectable to the control cable for signaling the logical switch via the control input cable. This apparatus controls power to the light source without a heavy duty mechanical switch and without a heavy duty electric branch cable that might be required by such a switch. The control input device includes at least one switch, and may include a plurality of switches each having a plurality of states including an ON state, the control input device sending an ON signal only when at least two of the plurality of switches are set in the ON state as a safety measure to avoid unintentional illumination. The control input device may further include a hand grip containing at least one switch. 
     Also in accordance with the present invention, apparatus for mounting equipment includes a first component including a rail; a second component including a slide adapted for longitudinal engagement to the rail, the slide having an open end adapted for receiving the rail endwise; a lock movably confined in the second component proximate the open end, the lock having a closed position wherein the lock confines the rail in the open end and an open position wherein the open end may receive or release the rail; an appendage projecting from the lock; a pin movably confined in the second component proximate the lock, the control pin having a notch shaped and oriented to receive the appendage, the control pin having a free position wherein the notch is aligned to receive the appendage, thereby allowing the lock to be in the open position, and a blocking position wherein the notch is misaligned with the appendage, thereby preventing the lock from being in the open position. 
     Preferably, the lock is biased in the closed position. Also preferably, the control pin is biased in the blocking position and manually movable to the free position. The lock may have lateral projections adapted for manually moving the lock between the closed and open positions. 
     Preferably, the control pin is movable from the free position to the blocking position only when the lock is in the closed position. One preferred embodiment includes a first surface feature on the appendage and a second surface feature on the control pin, the first surface feature and the second surface feature being adapted to cooperate to retain the lock in the open position while the appendage retains the control pin in the free position. This makes it more convenient for the operator to use both hands to manipulate the slide relative to the T-rail. 
     Also in accordance with the present invention, a key tool for tightening a plurality of types of bolts includes a rigid core having an axis of rotation; a first side of the core, the first side including a first key bit aligned with the axis of rotation; a second side of the core, the second side including a second key bit aligned with the axis of rotation; and a rigid torque handle protruding from the core outside the axis of rotation. The torque handle may be slidably disposed through the core and, preferably, has enlarged ends so that it will not slide free of the core. 
     Also in accordance with the present invention, a method of attaching an accessory mounting block to a shroud of an M2 machine gun, comprising the steps of placing an accessory mounting block in embracing relation to the shroud; inserting at least three plugs through the block until they contact the shroud; and tightening the three plugs onto the shroud. The method may further include a step of placing the block in a preferred alignment with the shroud while tightening the plugs. It may also further include a step of securing a retaining ring behind each of the plugs after tightening the plugs. 
     The steps of inserting and tightening may include a rotation of the plugs in helically threaded engagement with the block resulting in an advancement of the plugs onto the shroud. 
     The method may further include a step of securing a retaining ring behind each of the plugs after tightening the plugs. The step of securing the retaining rings may include a rotation of the retaining rings in helically threaded engagement with the block resulting in an advancement of the retaining rings into abutting contact with the plugs after tightening the plugs. The step of securing the retaining rings may further include a rotation of the retaining rings opposite the rotation of the step of inserting and tightening the plugs. 
     The method may further include a step of finding perforations on the shroud and aligning the plugs with the perforations before tightening the plugs. 
     Additionally, a second set of plugs may be used, so that first and second sets of three plugs each are inserted and tightened, enhancing stability and better distributing loads. 
     Also in accordance with the present invention, firearm in combination with an accessory adapter comprises a firearm and a shroud fixed to the firearm. A plurality of perforations are formed in the shroud. A block is adapted to embrace the shroud. An accessory adapter is removably securable to the block. At least one set of three plugs are provided, the plugs being adjustably securable through the block and being adapted to engage the perforations of the shroud. Preferably, the plugs are located and oriented on the block such that each of the plugs is alignable with one of the perforations while the block embraces the shroud. 
     The present invention generally envisions a rigid block which embraces and tightly grasps the shroud, a robust body firmly mounted to the block, and an electrically efficient cable and control apparatus for discreetly controlling a light beam generator or other accessory installed on the body. 
     With the shroud as it is commonly found on the M2, the block may be fixed to the shroud at any of a plurality of predetermined discrete locations spaced apart along the longitudinal axis of the shroud. At each of those locations, the block may be fixed in any one of three angularly spaced apart positions, so that an accessory fixed relative to the block may be positioned, for example, below the shroud or to one side of it. 
     As the block is being located and positioned, its alignment is adjustable within a small range of angles. The block is then fixed rigidly to the shroud and remains so, even when subjected to acceleration and vibration. The accessory is rigidly fixed to the block via the body, which engages a rail located on the block. 
     Briefly summarized, the structural features of a mounted accessory, such as a light beam generator are as follows: 
     The block has at least three plugs which engage at least one set of three coplanar perforations of the shroud. In a preferred embodiment, the block has two sets of plugs, three plugs each, spaced apart longitudinally to engage the three perforations in each of two sets of perforations on the shroud. 
     In an exemplary embodiment, the block has bores which locate and orient each set of three plugs to face inward, radially, toward the longitudinal axis of the block, spaced apart 120° in a plane perpendicular to the longitudinal axis of the block. 
     The plugs, so located and so oriented, engage perforations of the shroud, which are spaced apart approximately 120° in a plane approximately perpendicular to the longitudinal axis of the shroud. 
     In a preferred embodiment, the plugs and the bores are helically threaded so that, when the plugs are turned clockwise in their bores, they advance into the perforations of the shroud. The plugs are dimensioned to be too large to pass through the perforations, yet small enough to nose into the perforations and stabilize the block on the shroud when tightened. 
     The block also receives retaining rings which, when secured in the block are in contact with the plugs after the plugs have been tightened and prevent the plugs from backing out from vibration or rough handling. 
     The retaining rings and their corresponding bores are threaded so that, when the retaining rings are turned counterclockwise in their bores, they advance toward the shroud until they abut the plugs. 
     In a preferred embodiment, the threads of the plug are the ACME type: they have a square profile, are very strong, and are relatively unlikely to back out when shaken. 
     Each plug has a bluntly curved front end surface for smoothly engaging a perforation of a shroud. 
     The rear surface of each plug has a cruciform arrangement of notches into which a cruciform key bit is insertable to tighten or loosen the plug. 
     The rear surface of each retaining ring has at least one and preferably two pair of bores into which pegs of a pegged key bit are insertable to tighten or loosen the retaining ring. 
     The key tool carrying the cruciform and pegged bits is cylindrical and has a short cruciform bit on one face, two pegs on the other face, and a metal bar torque handle slidably inserted through its center, with stops at the ends of the torque handle so that it will not separate from the key tool. 
     The structures for attaching accessories may include one or more accessory mounting rails for small arm weapons, for example such rails known as Picatinny rails per Mil. Std. 1913, for attaching light accessories. 
     For attaching heavy accessories, the present invention provides a new rail, referred to herein as a “T-rail,” which is wider and sturdier than a Picatinny rail, and preferably has a rectangular-profiled central longitudinal groove. The T-rail may be formed integrally with the block, or it may be bolted onto the block. 
     A body is provided in accordance with the present invention for mounting an accessory such as a light beam generator. In a preferred embodiment, the body has a receiver portion which includes a slide and at least one guide post projecting into and riding in the groove, stabilizing the body as the retainer portion slides into or out of engagement with the T-rail. Additionally, the slide has a spring which also rides in the groove, so that less play is felt during engagement and disengagement of the retainer portion and the T-rail. 
     The retainer portion of the body in accordance with the present invention has a push-button-releasable, spring-loaded lock which prevents unintended disengagement of the body from the T-rail. 
     The body includes a forward-facing socket to which a light beam generator, camera, sight, or the like may be attached. The body also has an on-off switch and an electric socket for connecting electric power sources and controls. Where a high intensity discharge light source is attached to the apparatus housing included in a light beam generator, the apparatus housing also includes an internal electric ballast and an internal solid state logic switch. 
     A power and control cable provided in accordance with the present invention includes positive and negative power conductors, one or more control conductors, a connector matching these conductors to the electric socket on the body, a power source connector matching the power conductors to a socket of a power source, and one or more control input devices connected to the control conductors. A control input device may be a switch, in which case it may be incorporated into a handle and located on a branch cable. A gunner can, for example, hold the handle with one hand and operate the switch while aiming the M2 with both hands and operating its butterfly trigger with the other hand. Alternatively, a control input device may be located on a cable or in the apparatus housing and may be operable remotely via wireless signaling. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a further understanding of the objects and advantages of the present invention, reference should be had to the following detailed description, taken in conjunction with the accompanying drawing, in which like parts are given like reference numbers and wherein: 
         FIG. 1  is a side view of an M2 machine gun with an embodiment of an accessory mount adapter and a light beam generator accessory in accordance with the present invention mounted thereon; 
         FIG. 2  is a perspective view of a block portion thereof; 
         FIG. 3  is a perspective view of the block portion installed on an M2 shroud; 
         FIG. 4  is a side view of the block portion installed on an M2 shroud; 
         FIG. 5  is a sectional view of the block portion of  FIG. 4 , taken along line  5 - 5  in the direction of the appended arrows; 
         FIG. 6  is a perspective view of an embodiment of an accessory mount adapter in accordance with the present invention with a body portion with light beam generator accessory mounted on a block portion; 
         FIG. 7  is a partial sectional view of a body portion mounted to a block portion of an accessory mount adapter in accordance with the present invention; 
         FIG. 8  is a partial sectional side view of a body portion in accordance with the present invention in a locked configuration; 
         FIG. 9  is similar to  FIG. 8  but with the body portion in an unlocked configuration; 
         FIG. 10  is a perspective view of the light beam generator mounted to the adapter according to the present invention, partially exploded, including a cable portion thereof; 
         FIG. 11  is a circuit block diagram of the light beam generator and cable in accordance with the present invention; 
         FIG. 12  is a perspective view of a key tool according to the present invention showing a cruciform key bit; and 
         FIG. 13  is a perspective view of a key tool according to the present invention showing a pegged key bit. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The invention will now be described with reference to  FIG. 1 , which is a left side view of a first embodiment of an accessory mount adapter  20  and mounted light beam generator accessory  30  in accordance with the present invention mounted on a shroud  24  of an M2 machine gun  22  (viewing convention: “left side” is the side that would be on the viewer&#39;s left if the viewer was in front looking rearward), the longitudinal axis A being shown by a dotted line extending from the gunbarrel  26 . The mounted light beam generator accessory  30  includes a body  34  with a stem  36 , a handle  38 , and a light emitter assembly  40 . For installation, the block  32  is passed onto the muzzle end of the gunbarrel  26  and positioned so as to embrace the shroud  24 . It is then secured as is described below. The body  34  is slide-mounted onto the block  32  as is also described below. The stem  36  extends from the slidable receiver portion  35  (see also  FIG. 8 ) of the body  34 ; the handle  38  extends from the stem  36 ; and the lamp assembly  40  is carried by the body  34 . 
     With reference to  FIG. 2 , the generally tubular block  32  includes three heads  42  arranged circumferentially 120° apart, each head  42  having two longitudinally spaced apart, radially oriented main bores  44 . Each main bore  44  has an inner segment  46  with clockwise internal threading  82  and an outer segment  48 , having a greater diameter, with counterclockwise internal threading  84 . Each head  42  has a radially outward facing seating surface  50  with six threaded auxiliary bores  52 . Between the heads  42 , arranged circumferentially 120° apart, are two radially projecting, longitudinally oriented mounting rail structures such as Picatinny rails  54 . Vents  64  of various diameters are formed in the block  32 . 
     With continued reference to  FIG. 2 , the block  32  includes at least one radially projecting, longitudinally oriented T-rail  56 , which has a trunk  58 , a longitudinally oriented, radially outward facing central groove  60 , and laterally opposite wings  62 . 
       FIGS. 3 ,  4  and  5  show the block  32  installed on an M2 shroud  24 . Each inner segment  46  of each main bore  44  contains a plug  66  having a plug tail  68  with a raised periphery  70  presenting four notches  72  in a cruciform arrangement. Preferably, each plug  66  is bored out in order to reduce its mass, in which case the plug tail  68  consists of the periphery  70  with notches  72 . Each outer segment  48  of each main bore  44  contains a retaining ring  74  having an arrangement of four shallow bores  76 . Each retaining ring  74  surrounds a plug tail  68 . 
     The shroud  24  includes recurrences of a predetermined surface feature of the shroud. In a preferred embodiment, the shroud  24  is perforated by a plurality of perforations  28  (eighteen in this example) as it is presently configured. The perforations  28 , formed by casting or machining, are roughly circular, about 2 cm in diameter, and arranged in six sets of three perforations  28  spaced apart about 120° in a plane perpendicular to the longitudinal axis of the shroud  24 . Successive sets of perforations  28  are spaced apart about 1.5 cm longitudinally and offset by about 60°. The block  32  is located about the shroud  24  so that the two main bores  44  in each head  42  are aligned with two perforations  28  at a common angular position on the shroud  24 . The two Picatinny rails  54  and the T-rail  56  are oriented substantially parallel to the longitudinal axis A of the shroud  24  and the gunbarrel  26  (see also  FIG. 1 ). The block  32  can be realigned by ±120° with engagement to the same set of perforations  28 , or by +60°, +180 or +240 with relocation to an adjacent set of perforations  28 . 
     With continued reference to  FIG. 3  and also with reference to the side elevational view of  FIG. 4 , an auxiliary mounting rail structure, such as an auxiliary Picatinny rail  78 , has six feet  80  arranged to be bolted to the six auxiliary bores  52  in the seating surface  50  of the head  42 . Thus, an additional accessory may be mounted on the auxiliary Picatinny rail  78 , which may be bolted onto any of the heads  42 , providing a mounting angle different from that provided by the T-rail  56  and Picatinny rails  54 , which are preferably integrally formed with the block  32 . 
     As best shown in  FIG. 5 , which is a sectional view of the embodiment of  FIG. 4 , in a preferred embodiment, each plug  66  has clockwise heavy external ACME threading  86  engaging clockwise heavy internal ACME threading  82  on the inner segment  46  of a main bore  44 . The ACME threading has a rectangular profile and is used because it resists “backing out”. Also in the preferred embodiment, each retaining ring  74  has counterclockwise external standard threading  88  engaging counterclockwise internal standard threading  84  of the outer segment  48  of a main bore  44 . Each plug  66  has a nose  90  which is blunt, rounded, smooth, and too large to fit through a perforation  28 . Thus, the nose  90  may advance only partly into the perforation  28 , is relatively free to rotate against the shroud  24  when positioned at the perforation  28 , and finds a stable position in the perforation  28  when tightened against the shroud  24 . 
     With continued reference to  FIG. 5 , each plug  66  may be secured by placing the plug  66  in the inner segment  46  of the main bore  44  and turning it clockwise until it is snugly engaged against the shroud  24  at a perforation  28 , whereupon a cruciform key bit (see  FIG. 12 ) may be used to tighten the plug  66 . After the plug  66  is tightened, a retaining ring  74  is placed in the outer segment  48  of the main bore  44  and turned counterclockwise until it is snugly engaged against the plug  66 , whereupon a pegged key bit (see  FIG. 13 ) is used to tighten the retaining ring  74 . 
     With reference to  FIGS. 3-5 , an operator places the block  32  on the shroud  24  in a desired location and orientation with the plugs  66  loosely located in the main bores  44  and approximated to the desired perforations  28 , and gently hand tightens the plugs  66  to reduce the slack between the block  32  and the shroud  24 . If the alignment is satisfactory, the operator hand tightens the plugs  66  to eliminate the remaining slack, torques the plugs  66  with a cruciform key bit (see  FIG. 12 ), hand tightens the retaining rings  74  until they abut the plugs  66 , and finally torques the retaining rings  74  with a pegged key bit  142  (see  FIG. 13 ) cooperatively engaging shallow bores  76  in the retaining rings  74 . This procedure assures that the block  32  is satisfactorily aligned with the shroud  24 , firmly attached to the shroud  24 , and unlikely to be loosened by vibration or recoil. 
       FIG. 6  shows a perspective view of an embodiment of an accessory mount adapter  20  in accordance with the present invention with the body  34 , including a light beam generator accessory  30 , mounted below the block  32  on a horizontally oriented T-rail  56  (see  FIGS. 2-5 ) which projects downward from the block  32 . An additional accessory  31  may be mounted to the adapter  20 , such as on a Picatinny rail  54  which is attached to one head  42  of the block  32 . The body  34  includes a forward-projecting handle  38 , a downward-projecting stem  36  having a disable switch  114  and a rearward-facing electrical socket  112 , and a horizontally-oriented receiver portion  35 . The receiver portion  35  has left and right sides  37  including cut-outs  39  and left and right lock windows  41 ; a front end  92 , a rear end  94 , a top surface  95 , and an internal T-profiled slide  96  which is closed at the front end  92  and open at the rear end  94  and at the top surface  95 . A lock  102  is movably confined within the receiver portion  35  proximate the rear end  94  and has grips  108  extending leftward and rightward through the left and right lock windows  41 . The lock window  41  allows the lock  102  a vertical range of motion relative to the receiver portion  35 . As shown, the lock  102  is at the upward extreme of that range. A lock control pin  106  is movably confined within the receiver portion  35  proximate the rear end  94  and below the lock  102 , and projects rearward through the rear end  94 . The lock control pin  106  is longitudinally movable relative to the receiver portion  35 . The T-rail  56  is lodged within the slide  96 , the receiver portion  35  having been thrust backward onto the T-rail  56  to place the T-rail  56  firmly in contact with the front end  92 . Small portions of the T-rail  56  are visible through the cut-outs  39 . 
       FIG. 7  shows a rear sectional view of the receiver portion  35  mounted on the T-rail  56 . The T-rail  56  occupies the slide  96 . One of several centrally located guide posts  101  is shown projecting upward from the slide  96  and into the central groove  60  of the T-rail  56 . The guide posts  101  align and stabilize the slide  96  on the T-rail  56 . 
     With reference to  FIG. 8 , the lock  102  is movably positioned below the slide  96 . The lock  102  includes a slide-blocking portion  103  located proximate the slide  96 . Left and right lock springs  104  (only one of them is visible in this drawing figure since the two springs  104  are located on opposite sides of the T-rail groove  60  when the body  34  is installed on the T-rail) thrust upward from the receiver portion  35  and against the lock  102 , biasing the lock  102  upward, such that the slide-blocking portion  103  blocks the slide  96  at the rear end  94 . The lock  102  also includes a downward-projecting appendage  105  which has a rearward-projecting lip  113 . 
     With continued reference to  FIG. 8 , the lock control pin  106  is mounted in the receiver portion  35  proximate the rear end  94 , projects rearward therefrom, and is longitudinally movable therein. A release bias spring  107  is mounted in the receiver portion  35  proximate the rear end  94  immediately forward of the lock control pin  106  and biases the lock control pin  106  rearward. 
     With continued reference to  FIG. 8 , the lock control pin  106  has an upward-facing lock-receiving notch  109 . A roll pin  111  is fixed in the lock control pin  106  and projects forward a short distance into the lock-receiving notch  109 . As long as the lock control pin  106  is biased rearward, the lock-receiving notch  109  is not in position to receive the appendage  105  of the lock  102 . Thus, the lock control pin  106  blocks the lock  102  from moving downward, and the slide-blocking portion  103  blocks the slide  96 . 
     With reference to  FIGS. 8 and 9 , the operation of the lock  102  is described. To mount the slide  96  on the T-rail  56 , the slide  96  is advanced endwise onto the T-rail  56  so that the rear end  94  of the slide  96  receives the T-rail  56 . To facilitate mounting the slide  96  on the T-rail  56 , the lock control pin  106  is pressed forward manually, moving the lock-receiving notch  109  into position to receive the appendage  105 . Next, the slide  96  is advanced onto the T-rail  56 . The T-rail  56  enters the slide  96 , forcing the lock  102  downward, and then continues to advance past the lock  102 . To facilitate entry of the T-rail  56  into the slide  96 , the laterally extending grips  108  may be pushed downward manually to move the slide-blocking portion  103  of the lock  102  clear of the slide  96 , so that the T-rail  56  can more easily enter the slide  96 . Thus, as shown in  FIG. 9 , the appendage  105  is received in the lock-receiving notch  109 . 
     With continued reference to  FIGS. 8 and 9 , the receiver portion  35  includes an elastic bumper  98  located in the slide  96  near the front end  92  as well as a centrally located leaf spring  100  and three centrally located guide posts  101  projecting upward into the slide  96 . As the slide  96  is advanced onto the T-rail  56 , the leaf spring  100  is deflected by the T-rail  56  and stabilizes the slide  96  on the T-rail  56 . At the same time, the guide posts  101  further stabilize the slide  96  on the T-rail  56 . Both the leaf spring  100  and the guide posts  101  engage the central groove  60  of the T-rail  56 . After the slide  96  is fully advanced onto the T-rail  56 , the bumper  98 , located near the front end  92 , contacts the front edge of the T-rail  56  to stop further sliding of the receiver portion  35  on the T-rail  56 . At this point, the T-rail  56  has also cleared the portion of the slide  96  that can be occupied by the slide-blocking portion  103  of the lock  102 . Thus, after the slide  96  is advanced onto the T-rail  56  and the bumper  98  has been forced into contact with the T-rail  56 , the lock bias spring  104  forces the lock  102  upward, so that the slide-blocking portion  103  blocks the slide  96  behind the T-rail  56  and prevents the T-rail  56  from escaping from the slide  96 , as shown in  FIG. 8 . The bumper  98  may be made of an elastic material, such as rubber, such that, being compressed, it biases the T-rail  56  rearward against the slide-blocking portion  103 , reducing the likelihood of play between the T-rail  56  and the slide  96 . 
     With continued reference to  FIG. 8 , because the lock  102  is now biased upward toward the slide  96 , the appendage  105  is disengaged from the lock-receiving notch  109 , the lock control pin  106  is again biased rearward by the release bias spring  107  and is not in a position to receive the lock  102 . Even if the lateral grips  108  of the lock  102  are subjected to a downward force, the lock control pin  106  will block any downward movement of the lock  102 , confining the lock  102  in the upward position so that the slide-blocking portion confines the T-rail  56  inside the slide  96 . 
     Thus, with continued reference to  FIGS. 8 and 9 , to dismount the slide  96  from the T-rail  56 , the operator must downwardly depress the laterally extending grips  108  while pressing the lock control pin  106  forward. This moves the lock-receiving notch  109  to a position in which it may receive the appendage  105 , allowing the lock  102  to move downward and away from the slide  96 . 
     Additionally, with continued reference to  FIG. 9 , if the operator removes pressure from the lock control pin  106  while the appendage  105  is in the lock-receiving notch  109 , the release bias spring  107  will bias the roll pin  111  forward against the appendage  105  at a point above the rearward-projecting lip  113  of the appendage  105 . This interaction will hold the lock  102  in the lowered position, against the upward bias provided by the lock bias springs  104 , holding the lock  102  in the open position while the slide  96  is disengaged and removed from the T-rail  56 . If the operator then disturbs this interaction between the lip  113  and the roll pin  111 , for example, by pressing the lock-control pin  106  forward, the lip  113  is no longer caught on the roll pin  111  and the lock will be propelled upward by the lock bias springs  104 . 
       FIG. 10  shows the accessory mount adapter  20  in accordance with the present invention with the body  34  mounted on the block  32 . Also shown are the electrical socket  112 , disable switch  114 , and lamp socket  110  with a light beam emitter  40  installed. Also shown are a socket connector  116 , an electrical cable  118 , a constant on-off switch  120 , switch connectors  122 , a hand grip  124 , a hand switch  126 , battery connectors  128 , and a power adapter  130 . 
     With continued reference to  FIG. 10 , the socket connector  116  is adapted to connect the electrical socket  112  to the electrical cable  118 . The continuous on-off switch  120  is a two-position switch capable of opening and closing the connection between the socket connector  116  and the hand switch  126 . The switch connectors  122  allow easy substitution of other controls for the hand switch  126  or other switch configuration. The battery connectors  128  fit a standard battery such as a 12-volt storage battery. The power adapter  130  fits a 12-volt vehicle socket. 
       FIG. 11  shows a circuit block diagram of an embodiment of the light beam generator  30  in accordance with the present invention. The stem  36  includes the disable switch  114  and the electrical socket  112 . The electrical cable  118  includes the socket connector  116 , battery connectors  128 , power adapter  130 , continuous on-off switch  120 , and hand switch  126 . As represented, the lamp assembly  40  includes a high intensity discharge light source or lamp  132 , a ballast  134  for providing the proper voltage and current to the light source or lamp  132 , and a logical switch  136  for controlling power to the ballast  134 . The logical switch  136  preferably utilizes a FET. 
     With reference to  FIGS. 10 and 11 , because the lamp assembly  40  draws a high current, it would be disadvantageous to have a long conductive path, or switches, between the lamp assembly  40  and the battery connectors  128  and power adapter  130 . To keep the current path short and simple, switches have been eliminated from the electrical cable  118  and the battery connectors  128  and the power adapter  130  are connected directly to the logical switch  136 . To provide control, the disable switch  114 , which may be a push-button or toggle switch, the continuous on-off switch  120 , which may be a rocker switch, and the hand switch  126  are connected in series to control the logical switch  136 . The disable switch  114 , which is a pushbutton on-off switch, serves to disable the lamp assembly  40  when the operator needs to be sure the lamp  132  will not illuminate. The constant on-off switch  120  is a rocker on-off switch, usable as a safety switch during operations when the operator needs to continuously use both hands to operate the gun. The hand switch  126  may be a momentary switch, or any combination of constant and momentary switches, for controlling the lamp assembly  40  while aiming or firing the gun. 
       FIGS. 12 and 13  show a key tool  138  having a cruciform bit  140  on one face, a peg bit  142  on the other, and a torque arm  144  slidably threaded through the middle. The torque arm  144  in some embodiments of the present invention may have oversized ends so that it is not separated from the key tool  138  and lost. 
     In the preferred embodiment, the block  32 , plug  66 , retaining ring  74 , body  34 , and key tool  138  are formed of steel, aircraft aluminum, titanium, or other rigid durable material. The Picatinny rails  54 , T-rail  56 , and heads  42  are preferably formed integrally with the block. The electrical cable  118  includes insulated copper conductors enclosed in a sheath and adapted to connect to batteries and power sources which are expected to be found in the intended environment. 
     While the foregoing detailed description has described a preferred embodiment of an accessory mount adapter in accordance with the present invention, it is to be understood that the above description is illustrative only and not limiting of the disclosed invention. For example, it is not necessary to use the exact number of plugs  66  shown in the drawing, nor is it necessary for the shroud  24  to have the exact number, shape, or arrangement of perforations  28 . The blunt-nosed plugs  66  of the present invention are effective in stabilizing the block  32  on a shroud  24  having a wide variety of surface characteristics, although other plug configurations may be useful as well. Indeed, it will be appreciated that the embodiments discussed above and the virtually infinite embodiments that are not mentioned could easily be within the scope and spirit of the present invention. Thus, the present invention is to be limited only by the claims as set forth below.