Pistol sighting device

A laser sighting device for a pistol includes a universally mounted laser diode at the forward end of the pistol's trigger guard, wherein positioning of the laser beam is accomplished via adjustment screws from within the trigger guard. An energizing cable in the pistol structure is connected to a power supply located within the pistol's handgrip, and an externally operable activating switch is provided at the rear of the handgrip which is easily actuated by the user's hand immediately before the trigger is operated.

BACKGROUND OF THE INVENTION 
The present invention relates to a pistol sighting device and particularly 
to a laser sighting device adapted to form an integral part of a weapon. 
A number of law enforcement agencies have recently started employing laser 
attachments in conjunction with regulation handguns. When the weapon is 
fired at predetermined range, a laser beam from a device mounted on the 
weapon can accurately predict the point of impact of the bullet even under 
conditions of moderate ambient light by projecting a spot upon the target. 
Not only does the use of such a laser sight ensure effectiveness with 
respect to the intended target, but also lessens the likelihood of 
unintended injury by a stray or inaccurately fired bullet. 
Prior laser sighting devices have been in the nature of "add-on" structures 
attached to the police weapon in an obtrusive and ungainly manner so the 
weapon no longer can be received in a regulation holster. Moreover, such 
add-ons are easily damaged or unintentionally disengaged from the weapon 
unless considerable care is exercised with respect to their fragile 
structure. These devices can also be difficult to adjust in respect to the 
intended range of the weapon, and/or adjustment can be lost through 
mishandling such that the weapon can become more dangerous rather than 
more accurate. 
SUMMARY OF THE INVENTION 
In accordance with the present invention in a preferred embodiment thereof 
a laser gun sighting device is incorporated into a police pistol or the 
like for forming substantially an integral part thereof. A laser diode 
holder is mounted via universal positioning means at the forward end of 
the pistol trigger guard, such universal positioning means being easily 
adjustable for correcting the range and accuracy of the weapon. However, 
obtrusive parts do not extend outwardly from the weapon where they would 
be easily damaged or in a manner which would prevent the weapon from being 
received in a regulation holster. 
In accordance with a particular embodiment of the present invention, a 
laser diode power supply is received substantially entirely within the 
handgrip portion of the weapon and is provided with switch means located 
immediately to the rear of the handgrip, operable by the user's hand at 
the same time the user's forefinger is placed in engagement with the 
trigger. A plurality of conductors within the weapon connect the power 
supply to aforementioned switching means as well as to the laser diode. 
It is accordingly an object of the present invention to provide an improved 
sighting device for a pistol or similar weapon for enabling the dependable 
accuracy of such weapon. 
It is another object of the present invention to provide an improved 
sighting device which is substantially integral with a pistol or similar 
weapon so as to avoid obtrusive parts as might be easily damaged or as 
might prevent the insertion of the weapon into a standard holster. It is 
another object of the present invention to provide an improved sighting 
device for a pistol or similar weapon wherein said sighting device is 
easily and accurately adjustable. 
It is another object of the present invention to provide an improved 
sighting device for a pistol or the like which is easily operated by the 
user in conjunction with the operation of the weapon's trigger. 
The subject matter of the present invention is particularly pointed out and 
distinctly claimed in the concluding portion of this specification. 
However, both the organization and method of operation, together with 
further advantages and objects thereof, may best be understood by 
reference to the following description taken in connection with 
accompanying drawings wherein like reference characters refer to like 
elements.

DETAILED DESCRIPTION 
Referring to FIGS. 1-4, the sighting device according to the present 
invention is illustrated as mounted integrally with respect to a 
standardly employed police pistol, in this case a Glock 17. The pistol 
includes a frame 10 mounting a slide 12 and a barrel 14 for receiving a 
cartridge 16. The pistol frame is also provided with a recoil spring 18 
and a trigger guard 20 both of which extend in a direction longitudinal of 
the weapon, i.e., in parallel relation to barrel 14. At the lower rear of 
the pistol, handgrip 22 contains a magazine well for receiving a cartridge 
clip 24 carrying one or more additional cartridges 26. Trigger 28 
rotatably mounted within trigger guard 20 is adapted to operate trigger 
mechanism 30 in a manner understood by those skilled in the art for the 
purpose of firing the weapon and ejecting a bullet longitudinally from 
barrel 14. 
In accordance with the present invention, a laser device is positioned on 
the pistol forwardly of trigger guard 20, e.g. on the forward, 
substantially vertical portion 32 of the trigger guard, the laser device 
providing a laser beam 34 which is projected in substantially intersecting 
relation with the trajectory of a bullet fired from barrel 14. 
In particular, and in accordance with a preferred embodiment of the present 
invention, the laser device 248 (see FIG. 2) is mounted within a laser 
diode holder 36 provided with universal positioning means including 
threadably adjustable elements 38. Elements 38 suitably take the form of 
allen screws which extend horizontally (in a direction parallel to barrel 
14) through holes in the forward portion 32 of the trigger guard for 
threaded engagement with radial flange 40 of laser diode holder 36. The 
heads of screws 38 are adapted to receive a right angle allen wrench which 
may be extended into the trigger guard from the side thereof whereby to 
adjust the position of flange 40. 
The means for mounting the laser holder 36 further comprises a means for 
tiltably bearing the holder whereby adjustment of the screws 38 is 
employed for bringing about a desired degree of tilting of holder 36 with 
respect to the centerline of barrel 14 in order to properly aim laser beam 
34. In the preferred embodiment, such means for tiltably bearing the 
holder comprises a compressible member 42 formed of elastomeric material. 
The member 42 is desirably a rubber grommet through which cable 44 is 
axially received, the wires of which are connected to the laser device in 
the manner illustrated in FIG. 5. 
Four screws 38 are suitably employed to engage mating threaded holes in 
flange 40 as illustrated in the FIG. 4 cross sectional view. It is noted 
that flange 40, rather than being completely circular, is provided with 
left and right vertical edges 50 such that the width of the flange does 
not exceed the width of the trigger guard. The upper screws 38 (designated 
38a in FIG. 4) engage threaded holes spaced equidistantly on either side 
of the centerline of flange 40 above vertical edges 50, while lower screws 
38 (designated 38b in FIG. 4) are disposed equidistantly on either side of 
the vertical centerline of the flange below edges 50 and in substantial 
alignment below screws 38a. Respective adjustment of the screws 38 enables 
the individual adjusting of the sight to "rock" the laser diode holder 36, 
e.g. through tightening of one screw 38 and/or loosening the diagonally 
opposite screw 38 until the desired direction of beam 34 is procured. By 
adjustment of the various screws, the laser holder and therefore beam 34 
is readily adjustable in both the horizontal or x direction, and in the 
vertical or y direction. 
The final adjustment of the laser beam is undertaken at a point where all 
screws 38 are drawn up fairly tightly so that flange 40 nearly engages 
trigger portion 32 but is spaced therefrom by a sufficient distance so 
that the aforementioned adjustment can be accomplished. At this time, 
rubber grommet 42 is under compression and acts to provide back pressure 
on the laser diode holder for substantially locking the same at the 
desired orientation. Although four screws 38 are employed in the preferred 
embodiment of the present invention, a greater or lesser number can be 
utilized if so desired. 
Laser diode holder 36 comprises a hollow cylindrical member, internally 
threaded at its axially forward cylindrical portion 52 to receive 
externally threaded lens carrier 54, while rearward flanged portion 40 is 
counterbored to provide recess 46 that receives laser diode device 248 
which is locked into place within holder 36 by means of mechanically 
impressed punch marks or by another suitable expedient such as gluing 
whereby the laser beam produced thereby extends axially along the bore 
centerline of holder 36, and whereby electrical leads thereof extend 
rearwardly for connection to the conductors of cable 44 through the 
central aperture in grommet 42. 
The internal bore of hollow externally threaded lens carrier 54 is adapted 
to receive an apertured disk 58 at the forward end thereof which is 
employed to determine the desired beam size. In a particular embodiment, 
the aperture 62 in disk 58 was 0.03 inches in diameter. Threaded lens 
carrier 54 is counterbored rearwardly to receive collimating lens 56, with 
both lens 56 and apertured member 58 suitably being cemented within the 
threaded member 54. The forward edge of lens carrier 54 is provided with 
an adjustment slot 60 so that the lens carrier is conveniently screwed 
into laser diode holder 36 and adjusted for the desired laser beam size 
and quality. A drop or two of a substance such as manufactured under the 
trademark Loctite may be placed upon the external threads of lens carrier 
54 before insertion into diode holder 36 whereby a desired adjustment can 
be more easily maintained. 
Although laser sighting adjustments are easily accomplished, it will be 
noted that the device is structurally quite sturdy and very compact, 
lacking clamp-on means or adjustment means as might be completely 
dislodged, resulting in inoperativeness of the entire sighting mechanism, 
or which may simply lose proper adjustment as contact is made with another 
object. The mechanism as positioned at the forward end of the trigger 
guard and within the width dimension of the pistol does not normally 
encounter abrasion by other objects either during normal operation or 
during insertion or removal from a regulation holster but is strong enough 
to withstand contact as may occur without losing adjustment. In particular 
regard to screws 38, it will be seen that directional adjustment of the 
laser beam is accomplished within trigger guard 20 as heretofore 
mentioned, ensuring lack of disturbance of the adjustment. 
The power supply for the laser device is located within the rearward side 
of the handgrip behind the magazine well. In the case of the preferred 
embodiment, a power supply compartment is provided by removing excess 
material at the back of the handgrip to complete an elongated recess 64 in 
substantially parallel relation to the magazine well. This recess receives 
a battery holder 66 for housing battery 202, the holder having a 
convenient threadably engageable end cap 68. The positive terminal of the 
battery normally engages a raised rib on the inner side of end cap 68, 
while the remaining or negative terminal end of the battery contacts 
compression spring 70 held in place by means of battery spring retainer 82 
having a conductive portion for completing the battery circuit. An 
upstanding flange 72 at the upper end of the battery holder, at its 
desired depth within recess 64, supports the battery spring retainer. The 
circuit board 74 incorporates circuitry comprising the power supply or 
driving circuit for the laser diode device, being connected thereto by the 
aforementioned cable 44 comprising three conductive wires covered by 
"shrink tube". The cable 44 extends from circuit board 74 up through the 
back of the handgrip and is suitably secured within a groove milled 
directly below the pistol operating rod. The cable 44 then passes 
successively through drilled bores in the rear of the trigger guard, the 
lower or horizontal portion of the trigger guard, and front portion 32 of 
the trigger guard from where the it extends through rubber grommet 42 to 
the laser device as mentioned. The battery holder is suitably cemented 
within recess 64. 
An activating switch 204 is provided rearwardly of handgrip 22 and in 
particular comprises a pushbutton type switch located in a depression 76 
milled at the upper rear of the handgrip. The switch is enclosed 
rearwardly by a rubber switch cover 80 which, like the pushbutton, is 
cemented to the rear of the handgrip. Two conductors from the switch 204 
covered by "shrink tube" extend from the depression 76 through an aperture 
in the back of the handgrip under switch cover 80 and make proper 
connection with components on circuit board 74. 
The activating switch 204 is positioned for convenient operation by the 
user of the pistol. As the user grasps the pistol with his forefinger 
inserted through the trigger guard 20 in front of trigger 28, his hand, 
between thumb and forefinger, is naturally positioned at the rear of the 
trigger guard whereby the switch 204 can be compressed as desired. 
Compression of switch 204 connects battery 202 to the power supply or 
driver circuit on circuit board 74 for properly energizing the three 
conductors within cable 44 whereby beam 34 is emitted forwardly for 
supplying an advance indication of the intersection of the bullet with the 
target. 
In addition to advantages of sturdiness, ease and accuracy of adjustment, 
and integration with the weapon, it will be appreciated the device 
according to the present invention is easily incorporated into existing 
hand guns. 
In a particular embodiment of the present invention a Toshiba laser diode 
device type TOLD 9211 was employed together with an appropriate power 
supply therefor. A schematic illustration of such a device together with 
an example of a power supply circuit are provided in FIGS. 5 and 6 
respectively. 
Referring to FIG. 5 there is illustrated a configuration wherein a photo 
diode 222 is used to monitor the intensity of light emitted from laser 
diode 240, wherein both are physically mounted in the same envelope 248. 
The anode of laser diode 240 and the cathode of photo diode 22 are both 
coupled to terminal 242 while the cathode of laser diode 240 is connected 
to terminal 246 and the anode of photo diode 244 is connected to terminal 
244. Since laser diodes are temperature-dependent in their operation, the 
current required to obtain a specific optical output varies with 
temperature. The linear relationship between the light intensity of the 
laser diode output and the resulting current passing through the photo 
diode is used to regulate this current. 
FIG. 6 is a schematic diagram illustrating a power supply or driving 
circuit for laser diode 240 and photo diode 222. The ungrounded terminal 
of a capacitor 206 is connected to the base of transistor 212 as well as 
to the first terminal of resistor 210. The negative terminal of battery 
202 is coupled through switch 204 to the second terminal of resistor 210, 
the collector of transistor 212, and the collector of transistor 214, the 
base of the latter being coupled to the emitter of transistor 212. The 
emitter of transistor 214 connects to a first terminal of resistor 216, 
the anode of zener diode 226, a first terminal of capacitor 228 and a 
first terminal of resistor 236. Variable resistor 218 is interposed 
between the second terminal of resistor 216 and the anode of photo diode 
222 having its cathode returned to ground. Resistor 220 couples the anode 
of photo diode 222 to the non-inverting input of op-amp 224 having an 
output connected by resistor 250 to the inverting input of op-amp 230. 
Op-amp 230 is connected at its non-inverting input to the cathode of zener 
diode 226, the second terminal of capacitor 228, and via resistor 252 to 
ground. Resistor 234 and capacitor 232 in parallel couple the inverting 
input of op-amp 230 to the emitter of transistor 238 and to the second 
terminal of resistor 236. The base of transistor 238 receives the output 
of op-amp 230 and is coupled at its collector to the cathode of laser 
diode 240, the anode of which is grounded. 
Closing switch 204 is intended to result in a forward bias across laser 
diode 240 whereby current passing through the diode via resistor 236 and 
transistor 238 produces light emission. However, capacitor 206 and 
resistor 210 function in conjunction with transistors 212 and 214 to 
filter voltage spikes. For example, when switch 204 is initially closed, 
capacitor 206 conducts current providing a positive voltage across 
resistor 210 and shutting off transistor 212. Therefore the emitter of 
transistor 212 does not sink current from the base of transistor 214 and 
transistor 214 is shut off. Consequently laser diode 240 is back biased. 
As capacitor 206 charges, the voltage bias across the collector-base 
junction of PNP transistor 212 drops, turning on transistor 212 and 
allowing the emitter of transistor 212 to sink current from the base of 
transistor 214. The current passing through transistor 214 progressively 
increases for forward biasing laser diode 240. This gradual increase of 
current supplied laser diode 240 prevents damage due to instantaneous 
application of current. Of course, the whole procedure is completed in a 
fraction of a second. 
As the current passing through laser diode 240 increases, the intensity of 
emitted light increases, and when the light intensity passes a threshold 
level, the current passing through diode 222 also begins increasing 
linearly. As a result, the voltage level at the non-inverting input of 
op-amp 224 rises, thereby increasing the voltage at the inverting input of 
op-amp 230. As the voltage at the inverting input of op-amp 230 rises 
above the voltage level set at the non-inverting input of op-amp 230, 
current is cut back to the base of transistor 238 and the current passing 
through transistor 238 decreases for reducing the amount of current 
passing through laser diode 240. As the light intensity of laser diode 240 
decreases due to a reduction in current, the opposite sequence of events 
takes place. Variable resistor 218 provides an adjustable means for 
changing the light emission intensity of the laser diode by controlling 
the voltage at the non-inverting input of op-amp 224. 
Also to prevent the laser diode from being damaged from rapid charges in 
supply current, the base current supplied to transistor 238 is integrated 
by op-amp 230. Resistor 234 and capacitor 232 serve as feedback 
controlling the rise and fall time for the output of op-amp 230. 
While a preferred embodiment of the present invention has been shown and 
described, it will be apparent to those skilled in the art that many 
changes and modifications may be made without departing from the invention 
in its broader aspects. The appended claims are therefore intended to 
cover all such changes and modifications as fall within the true spirit 
and scope of the invention.