Abstract:
An aiming system having a two-tone colored rear sight lens as the primary aiming component. The lens is held in an L-shaped lens frame which also incorporated conventional “iron sights.” The two-tone colored lens has an outside perimeter portion of one color and a central portion of another color. The lens frame can fold or rotate forward from an upright locked position to a locked-down position using a manually activated one-handed operation.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to the field of firearm sighting devices, and in particular to a flip-up aiming sight having a two-toned colored lens as the primary aiming component. 
     Traditional open sights use a static mechanical (non-electrical) configuration to aid a shooter in acquiring a correct sight picture. A sight picture is the orientation of a gun sight to a target. A correct sight picture combines sight alignment with the point of aim. Traditional open sights are comprised of an open, unmagnified system used to assist in aiming a firearm. The classic, traditional open sight system is comprised of a rear sight mounted vertically transverse to the line of sight, said rear sight consisting of some form of notch or aperture. The classic open sight is further comprised of front sight comprised of a post, bead or ring. On many firearms, the rear sight is adjustable for windage and/or elevation. When aiming, the front sight is brought to the central part of the notch or aperture, preferably the middle, for lateral aiming, and at the same height as the rear sight for vertical aiming. 
     Open sights are often enhanced for low-light situations with a three-dot system. A distinctive white dot (or other colors if preferred) is added to the front sight and on either side of the rear sight notch. When properly aimed, the sight picture appears as three white dots aligned on a horizontal plane. 
     The main limitation with traditional open sights is the difficulty the human eye has in focusing simultaneously on three separate objects, i.e., rear sight, front sight, and target. It is difficult to align the front post in the center of the notch with equal distance on either side of the front post, while simultaneously aligning the top of the front post level with the top of the rear notch sight. From a strictly physiological standpoint, the human eye cannot focus simultaneously on more than one object at a time. Due to the juxtaposition of the weapon being closer to the eye than the target, the eye will focus either on the rear sight making the front sight and the target a blur, or on the front sight making the rear sight and the target a blur, or on the target making the two gun sights a blur. 
     Compounding the sighting problem with open sights are two conditions known as “sympathetic nervous system” (SNS) and parasympathetic nervous system” (PNS). SNS is the involuntary reflective response that the human body experiences when the brain perceives either a life-threatening situation or a person is suddenly startled. This is an involuntary physiological response to external stimuli. SNS is also known as the “fight or flight” reflex. Under SNS the body does a “mass discharge” of hormones that helps prepare the body to defend or flee (fight or flight response). The immediate physical changes the body undergoes is simply the body preparing to defend itself from a threat or to take flight and avoid the threat if possible. The mass discharge of hormones includes an increase in arterial pressure and blood flow to the large muscle groups (to enhance gross motor skills and strength), vasoconstriction of minor blood vessels in the extremities, pupil dilation, cessation of the digestive process, and muscle tremors. Once the threat is eliminated, the body returns to its normal state, which is governed by the parasympathetic nervous system. PNS is normally in control of the body in the absence of any threat stimulus, i.e., a non-stressful environment. Fine and complex motor skills are exhibited; full peripheral vision is possible; and heart rate and blood are at their normal state. Gross motor skills are those actions by large or major muscle groups involving strength and simple symmetrical movements such as punching, swinging a club, kicking a ball, etc. Fine motor skills employ hand/eye coordination and hand dexterity such as aiming/firing a weapon, working with tools, typing on a keyboard, etc. Complex motor skills make use of a series of muscle groups that require hand/eye coordination, precision movements, tracking and timing. In shooting, complex motor skills require a series of movements and muscle groups to focus on the target while sighting the weapon. 
     SNS impacts the brain in the areas of motor skills, sensing perception (in particular, impaired vision), and mental processes. With respect to vision impairment, there are three areas that are affected: reduced peripheral vision, distance-only eyesight, and forced binocular vision. Reduced peripheral vision is caused by restricted blood flow to the eyes and muscle contractions. The eye lens tends to flatten, thus reducing depth perception resulting in the effect known as “tunnel vision.” SNS causes the body and eyes to focus on the source of a threat and ignore near objects. Near objects are almost impossible to discern resulting in distance-only eyesight. Forced binocular vision is caused by the body naturally squaring off to face a threat. Eyes open wide to admit as much light as possible to help the body discern the nature of the threat and how to react to it 
     Shooters who are familiar with or professionally trained in handling firearms know it is difficult to place shots consistently and accurately on target under stress-free or controlled, non-threatening situations, e.g., target practice. However, when the brain perceives a life-threatening situation and SNS activates within the body, the physical effects of the “mass release” of hormones directly impact the shooter&#39;s ability to deliberately focus on the target and fire the weapon. 
     In conducting tests of trained police officers, Burroughs (1997) found that 59% reported not actually “seeing” or using their sights that involved high stress (SNS) scenarios, but focused almost exclusively on the threat/target itself. Additional studies have shown that the effects of SNS impairs hearing (auditory exclusion) and peripheral vision (tunnel vision). 
     That trained officers, when confronting life-threatening situations, revert to the basic instincts of “fight or flight” further strengthens the argument that traditional gun sights are marginally functional in those situations. Therefore, there remains the need for a simple, reflexive gun sight that takes advantage of a human&#39;s instinctive reactions, such as forced binocular vision, where the shooter is focused solely on the threat/target. It is also desirable, to provide an aiming system that facilitates the ease, speed and accuracy with which a shooter aligns his weapon on a target thereby meeting the need to get on target fast and accurately. 
     The present invention proposes a color-activated gun sight (as opposed to geometrically aligned gun sights) to meet this need. The present invention will aid the shooter in acquiring a correct sight picture and accurate shot placement even in high stress situations without taking one&#39;s eyes off the threat itself. 
     SUMMARY OF THE INVENTION 
     The present invention provides a rear-mounted sighting aid for handguns or rifles that facilitates the ease, speed and accuracy with which a shooter aligns his weapon on a target. The present invention uses a two-tone colored, rear sight lens as the primary aiming component. The lens is held in an L-shaped lens frame, which also incorporates conventional “iron sights.” The invention uses a front sight post with an embedded tritium insert that appears illuminated in low-light situations. The premise of the present invention aiming system is that the human eye can discern changes in color faster than attempting to align the sight picture using tradition three-dot or notch-and-post configurations, thus enabling the shooter to get on target faster and more accurately. 
     The two-tone colored lens of the present invention is unique and has two regions: an outside perimeter of one color and a central portion of another color. For exposition purposes, the perimeter will be red and the central portion green. Other color combinations may be used providing there is contrast between the two colors. In operation target acquisition is achieved when the bright front post, using a tritium insert, is aligned with the target and also appears inside the lens central green circle. If the shooter detects the front tritium sight in the lens perimeter red zone, the shooter is slightly off target and must re-align to get the correct sight picture before firing the weapon. This slight peripheral realignment is accomplished while the shooter keeps his or her eyes focused on the target/threat. 
     The lens frame can fold or rotate forward from an upright locked position to a locked-down position using a manually activated one-handed operation. In the locked-down position, the integral iron sights, i.e., rear notched aperture, come into play and the weapon can be sighted using the conventional rear notch or three-dot system. Thus the shooter has the option of deploying the colored aiming lens or iron sights as the situation dictates. 
     The lens, when deployed, presents a shooter with a sight picture comprised of a small transparent green sighting area (or other contrasting color) that is the primary focal point when aiming the weapon. The lens, itself, is comprised of a small central green sighting area superimposed on a red (or other contrasting color) “no-shoot” field. The red field signifies that the shooter is not on target when viewed through the aiming lens. 
     There have been a number of studies done in the past which support the premise that the human eye can detect changes in color faster than aligning geometric shapes and objects, the most prominent being the early work of John R. Stroup (1935) which demonstrates how the eye and brain process information related to colors versus words or objects, i.e., “color recognitive processes.” In the “Stroop Test” a reader is presented with a page of typed words spelling out various names of colors. The fonts also are of the same color. For example, the word “red” is also in red ink. People have a natural ability to quickly read and assimilate related colors and words. However, when presented with a different scenario where the reader is given a page of words where the font color of the letters is different from the color being spelled out (for example, the word “green” in red ink), Stoop observed different results. When the reader was told to pick out the number of instances where the word “red” appeared on the page, the reader reverted to just color selection alone and not the word they were told to find. In this scenario, the reader took more time to read and process the word “red,” which might appear in a different font color while other words spelling out the names of colors were in red font. This supports the hypothesis that the human eye and brain are predisposed to note changes in color faster than it can process shapes (or in this case letters). The easiest and most common association of color versus words/objects is traffic lights. Evan at a distance one can discern the inherent message, i.e., green means “Go” while red means “Stop.” 
     Work performed by sports optometrist Dr. Hal Breedlove in 1995 demonstrated that during SNS activation a person&#39;s field of view can be reduced by as much as 70%, as well as failing to detect subtle threat movements, owing to the loss of peripheral vision (tunnel vision), and that the dominant eye (used for precision shooting, i.e., monocular vision) is lost. As stated above, during SNS the head tends to square off on the threat and causes the shooter to use both eyes wide open (binocular vision) as the dominant field of focus. Several other studies support this conclusion. Westmoreland (1989) examined 98 shooting scenarios involving non-stressed (PNS) and stressful (SNS) situations and found overwhelmingly that trained officers reverted to a squared-off stance (isosceles stance that focuses on the immediate threat) when confronted by life-threatening situations and did not focus on the gun sight. Burroughs (1997) found that when placed in potential life-threatening situations, a shooter instinctively faces or squares off to the potential threat, and the shooter loses focus for near objects (gun sights). Burroughs found that 59% of his subjects reported not actually “seeing” or using their sights under high stress (SNS) type scenarios, but focused almost exclusively on the threat/target itself. Ashton/Quinlan (1997) confirmed loss of focus on the front sight, and loss of auditory input (auditory exclusion) while under stress/SNS. 
     The ability to focus on close objects (like gun sights) is a function of parasympathetic nervous system (PNS), which is in control during periods of non-stress, and whereby the eyes and brain function with normal reflexive action. However, that control is immediately inhibited when SNS is activated. Guyton&#39;s Medical textbook states that during PNS, the normal body state (non-stressful), the human eye takes up to one full second to refocus from a near object to a distant object, but when SNS is activated, the human eye loses its ability to focus on near objects. 
     There are, therefore, several factors simultaneously in play when considering the use of the present invention: empirical studies supporting the premise of the human eye reacting faster to changes in color over alignment of notch-and-post or three-dot sighting systems, and the reactions and defense tactics humans instinctively employ when faced with life-threatening situations. 
     To help mitigate the SNS tendency to ignore physical gun sights and to help shooters quickly get on target, the present invention presents a field of view that allows the shooter, even under stressful conditions, to always focus directly on the target and not on the weapon&#39;s aiming points. This is accomplished by the present invention&#39;s contrasting colored lens. This helps the eye to quickly align the weapon by superimposing the lens on the target, but without actually having to shift the field of focus from the distant target to the near gun sights. When using the present invention lens in the upright position, the weapon is brought into the shooter&#39;s line of sight (hand/eye coordination), but without taking the eyes off the target (binocular vision). With the present invention two-color lens deployed, the shooter superimposes the weapon&#39;s sighting system onto the target. When the eye detects a slight change in color represented by the front post centered within the rear sight lens, the shooter knows he is on target and can fire the weapon. When aiming the weapon in this fashion, the shooter never takes his eyes off the potential threat or target. There is no need, therefore, for the eyes to re-focus from the near object (the gun sights) to the far object (the target). 
     These together with other objects of the invention, along with various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed hereto and forming a part of the disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated a preferred embodiment of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a handgun with the invention flip-up aiming sight. 
         FIG. 2  is a top view of the aiming system rear sight, with lens lined for colors. 
         FIG. 3  is a rear view of the aiming system rear sight with the flip-up lens in a stored position. 
         FIG. 4  is a plan view of a hinge pin. 
         FIG. 5  is a top view of the invention rear sight base unit. 
         FIG. 6  is a side view of the invention rear sight base unit. 
         FIG. 7  is a top view of the rear sight flip-up lens. 
         FIG. 8  is a side view of the rear sight flip-up lens. 
         FIG. 9  is a view of various lens configurations available for use in the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings in detail wherein like elements are indicated by like numerals, there is shown an aiming system  30  constructed according to the principles of the invention, said aiming system  30  being mounted on a handgun  10 . For purposes of exposition, the handgun shown is a conventional auto-loading, semi-automatic pistol. The handgun  10  has a front  11 , rear  12 , top  13 , bottom  14 , and two opposite lateral sides  15 . The handgun  10  is further comprised of a frame  16 , a slide  17  and a fire control mechanism that operates via actuation of a trigger  18 . The slide  17  is that portion of the handgun that forms the top of the handgun and is displaceable on the frame  16 . The slide houses a barrel  19  in the forward end thereof. The barrel  19  is cooperatively linked with the slide  17  and, together with the slide  17 , defines a longitudinal firing axis  20 . The handgun bottom  14  is defined by a handgrip  21  into which a magazine  22  is inserted. Upon handgun discharge, the slide  17  will travel rearward with the recoil from the discharged bullet and return again to the firing position. The aiming system  30  is incorporated onto the slide via dovetails, although grooves or mounting screws could also be used. 
     The aiming system  30  is comprised of a front sight  31  and a rear sight  40 . The front sight  31  is a post or vertical protrusion formed on the handgun slide  17  near the handgun front  11 . The rear sight  40  is mounted on the handgun slide  17  near the handgun rear  12 . The front sight  31  has a rearward side  32  facing the rear sight  40  and an opposite forward side  33 . The front sight rearward side  32  has a tritium insert  34 . The insert  34  is a tiny glass vial of a radioactive gas. The inside of the vial is lined with a phosphor. The phosphor glows when excited by particles from the radioactive gas. Tritium inserts are commonly used as a self-powered lighting device to illuminate the front sight post in low-light conditions. The front sight post with tritium insert is also highly visible in daylight. The usual color of the tritium insert  34  is a glowing greenish color. There are, however, several other colors available commercially, including orange and yellow. The front sight post may also optionally be painted white around the tritium insert to enhance daylight visibility. 
     The aiming system rear sight  40  is attached to the handgun slide  17  near the handgun rear  12 . The rear sight  40  comprised of a base unit  50  and a flip-up lens  70  pivotally attached to said base unit  50 . The base unit  50  has a front  51 , a rear  52 , a left side  53 , a right side  54 , a top surface  55  and a bottom surface  56 , said base unit front  51  and rear  52  defining a base unit longitudinal axis, said base unit longitudinal axis being parallel to the handgun longitudinal firing axis  20 . The base unit  50  is further comprised of a dovetail component  45 , either separately attached to or integral with the base unit bottom surface  56 . The dovetail component  45  is fitted into a dovetail slot  23  machined into the handgun slide  17  near to the handgun rear  12 . The dovetail component  45  can be either integral to the base plate bottom surface  56 , i.e., a one-piece machined component, or a separate component that attaches to the base unit  50 . If the dovetail component  45  is a separate component, it is attached to the base unit  50  via set screws  46  through several of a plurality of apertures  57  in the base unit  50  and into corresponding apertures  47  in the dovetail component  45 . In either case, the dovetail component  45  fits into the handgun slide dovetail slot  23 , thereby attaching the rear sight  40  to the handgun  10 . 
     The base unit  50  has two raised side rails  60  and  61  on the base unit top surface  55 , each side rail  55  adjacent a base unit side  53 ,  54 , respectively, and extending from the base unit front  51  to the base unit rear  52 . Said base unit front and rear define a longitudinal axis for each side rail. The base unit  50  is further comprised of two hollow hinge cylinders  65  attached to the base unit rear  52 . Each cylinder  65  has a central axis transverse to the longitudinal axis of the base unit  50 . Each cylinder  65  has two ends, an exterior end  66  and an interior end  67 . Each hinge cylinder exterior end  66  terminates at a base unit side  53  or  54 . Each hinge cylinder interior end  67  faces the opposite hinge cylinder interior end  67 . Each hinge cylinder interior end  67  terminates in a coil spring  68 . 
     The flip-up lens  70  is comprised of a lens frame  80  holding a lens  100 . The lens frame  80  has a distal end  81 , a proximal end  82 , two opposite sides  83 , a front surface  84  and a rear surface  85 , said distal and proximal ends defining a lens frame longitudinal axis. The lens frame longitudinal distance along its longitudinal axis is less than the base unit longitudinal distance along its longitudinal axis. The lens frame  80  has a hinge cylinder  86  centrally attached to the lens frame proximal end  82 . The lens frame hinge cylinder  86  is adapted to being positioned centrally between the two base unit hinge cylinders  65  and engaging the two base unit coil springs  68 . The lens frame  80  is rotatably attached to the base unit  50  by means of an elongated hinge pin  71  inserted into the base unit hinge cylinders  65  and lens frame hinge cylinder  86 , thereby holding the lens frame hinge cylinder  86  between the base unit hinge cylinders  65 . 
     The lens frame side-to-side width  83 - 83  is less than the distance between the base unit side rails  60 - 61 . The lens frame  80  is adapted to two positions. The first lens frame position is a pivoted ninety degrees upright from said lens platform top surface  55  along a pivot axis formed by the central axes of the two base unit hinge cylinders  65  and the lens frame hinge cylinder  86 . The lens frame front  84  faces the aiming system sight front sight  31 . This is termed the flip-up lens  70  operational position. The two base unit coil springs  68  urge the lens frame  80  into this position. The second lens frame position is to lay flat against the lens platform top surface  55  between the base unit side rails  60 ,  61 . This is termed the flip-up lens stored position. The base unit side rails  60 ,  61  provide protection from lateral forces to the lens frame  80  while in the second position. 
     The lens frame rear  85  at the lens frame proximal end  82  has a ninety degree flange  87  formed therein, said flange  87  incorporating an “iron” aiming sight comprised of a notch  88  formed centrally in said flange  87 . In the flip-up lens “stored” position, the flange  87  and notch  88  are positioned ninety degrees upright from the lens frame rear surface  85  at the lens platform rear  85 . The notched aiming sight  88  may also have tritium inserts  34  or white dots  89  embedded on each side of the rear notch  88  to help align the aiming system  30  in low light conditions. 
     The lens frame left side  83 ′ has a tab  72  formed therein, near to the lens frame distal end  81 . The tab  72  protrudes laterally away from the lens frame left side  83 ′. The base unit left side rail  60  has three apertures, i.e., a first aperture  62 , a second aperture  63  and a third aperture  64 , formed therein along the left side rail longitudinal axis. The left side rail first aperture  62  extends through the left side rail width and corresponds to the lens frame tab  72  when the lens frame is in a stored position. The left side rail second aperture  63  is positioned rearward of the left side rail first aperture  62  and extends partly through the side rail. A lock-down lever  73  is inserted into the left side rail first and second apertures  62 ,  63 . The lock-down lever  73  is comprised of a pivot element  74  inserted into the second aperture  63 . The lock-down lever  73  is further comprised of an action element  75  attached to said pivot element  74  and extending into and partly through the first aperture  62 . The lock-down lever  73  is further comprised of a control element  76  attached to said pivot element  74  and extending rearward parallel to said left side rail longitudinal axis. The lock-down lever action element  75  is adapted to engage the lens frame tab  72  thereby preventing the lens frame from moving from its stored position to an operational position. By pressing the lock-down lever control element toward the left side rail  60 , the action element  76  is pivoted about said pivot element away from the lens frame tab  72  thereby allowing the base unit coil springs  68  to bring the lens frame  80  into the operational position. 
     The left side rail third aperture  64  is positioned near to the base unit rear  52  and is adapted to receive a plunger  90 . The lens frame  80  has a curved notch  91  formed in the lens frame left side  83 ′ extending from the lens frame front  84  to the lens frame proximal end  82 . The plunger  90  is spring-loaded and extends through the left side third rail aperture  64  into the lens frame left side curved notch  91  when the lens frame is in an operational position. The plunger spring  92  urges the plunger into the notch  91 . To fold the lens frame down into its folded position, the plunger  90  is pulled out of the notch  91  and the lens frame folded down to the base unit top surface  55 . The plunger  90  is then released and the plunger tip  93  is brought into contact with the lens frame left side  83 ′, outside of the notch  91 . 
     The lens frame  80  is machined to accept a thin, two-toned, tinted, transparent lens  100 . The lens  100  is preferably comprised of a polycarbonate material, which is shock and shatter proof to withstand recoil when the handgun is fired. The lens frame  80  has a central, rectangular aperture  95  which may be may be grooved or beveled along the central aperture four sides, thereby forming a lens frame rear surface recessed area  96  about the lens frame central aperture  95 . The lens  100  is fitted into the recessed area  96 . A lens retention plate  110  with the dimensions of the lens frame recessed area  96  is fitted over the lens  100 . A plurality of set screws  111  are inserted through the lens retention plate  110  into the lens frame  80  to snugly hold the lens  100  in place. 
     The two-tone colored lens  100  of the present invention is unique and has two regions: an outside perimeter  101  of one color and a central portion  102  of another color. The lens  100  may be of several contrasting color configurations thus giving the shooter the option of switching lens under various shooting conditions. The contrasting colors can be any suitable combination that helps the shooter distinguish between the shoot  102 /no shoot  101  zones. The lens central portion  102  may have various geometries, i.e., circular, rectangular, oval, and the like. 
     In operation, the handgun  10  would be typically holstered with the lens frame  80  in the second position, i.e., folded and locked down onto the base unit  50 . When needed, the handgun  10  would be drawn from a holster (not shown). The shooter than actuates the lock down lever control element  76 , releasing the lock down lever action element  75  from the lens frame tab  72 . The hinge coil springs  68  then urges the lens frame  80  upright to the operation position. The handgun  10  would be raised to eye-level to aim on target. The shooter would super-impose the aiming system, especially the two-tone lens  100 , on target so that the lens central portion  102  and front sight  31  are aligned on target, all the while keeping the eyes focused on the target, not on the weapon&#39;s aiming system  30 . When the eye detects the front sight  31  in the rear sight lens central portion  102  and the shooter still has the target sighted via normal eye sight, the handgun  10  is on target and ready to be engaged. 
     It is understood that the above-described embodiment is merely illustrative of the application. Other embodiments may be readily devised by those skilled in the art, which will embody the principles of the invention and fall within the spirit and scope thereof.