Abstract:
An improved elastomer driven slingshot device having an adjustably mounted laser beam source adaptable to accommodate both distance to the target and variations in the projectile velocity whereby target accuracy is enhanced.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present device relates to elastomer driven projectile devices or sling shots and, in particular, to sling shot devices which embody improved means for accurate aiming.  
           [0002]    Hand elastomer-driven projectile devices or slingshots for hunting that use energy stored within a strained elastic member or elastomer for propulsion of a projectile have been known and used for centuries. Such hand held slingshot devices are difficult to aim and generally have poor target accuracy.  
           [0003]    There are often circumstances wherein a silent non-lethal projectile device is useful. Examples would be found in small game hunting, including non-lethal efforts to discourage small animal invasion of homes and farm animal feeding areas or shelters. A silent non-lethal projectile to anesthetize, discourage, or frighten a non-domesticated small animal such as a racoon, squirrel or other rodent is frequently needed.  
           [0004]    A sling shot device with an adjustable energy projectile and improved aim is a useful, silent, and safe alternative to a fire arm for controlling small animal invasions of home and farm property.  
           [0005]    Recreational use by children and adults of target aimed devices propelling a safe, non-injurious projectile is widespread. The present invention may be readily adapted to firing non-injurious projectiles with enhanced target accuracy. To overcome the problem of poor accuracy, the invention uses an aiming mechanism employing a laser beam.  
           [0006]    There have been numerous earlier projectile devices for propelling bullets, metal balls, arrows, non-lethal plastic projectiles, etc., which have included a light ray or laser beam on to the intended target to assist the marksman. Examples of the earlier devices are: Feldman U.S. Pat. No. 3,614,947 “Arrow Projecting Device with Arrow Projecting Mechanism” wherein the target is illuminated with a light beam directed to the target and attached to the projectile device for nighttime fishing. Lorocco U.S. Pat. No. 6,016,608 “Sighting Device for Projectile-Type Weapons”, utilizing an optical fiber light beam improved target accuracy. Moore U.S. Pat. No. 5,621,999 “Externally Mountable Laser Sight with Slide Switch” for illuminating a pistol target with a laser beam.  
           [0007]    These and other earlier inventions utilize light beams and laser beams to illuminate a target, however the present invention differs in a novel and important manner from all the earlier disclosed devices. The present invention provides means for the marksman to adjust the laser beam sight to accommodate the parabolic trajectory of his projectile for distance and variable velocity of the projectile based upon the elastomer strain.  
         SUMMARY OF THE INVENTION  
         [0008]    The invention embodies a projectile firing system that uses energy within a strained elastic member (elastomer) to propel a projectile and a laser aiming device to enhance target accuracy. It is fundamental to the physics underlying projectile motion that a projectile fired along a trajectory having a component parallel to the earth&#39;s surface travels along a parabolic curve. The deviation of a parabolic trajectory from a flat straight line trajectory depends upon both the initial velocity of the projectile as well as on the distance between the device and the target. It is for this reason that most rifles have a sighting means which may be adjusted to conform the rifle muzzle angle with the estimated parabolic trajectory of a projectile horizontal depending upon the distance to the target.  
           [0009]    The particular and unique improvement of the present invention is the placement of an adjustably-mounted laser aiming mechanism on a slingshot that is adapted for firing variable energy projectiles. The laser aiming mechanism of the invention includes an adjustment means in the mounting of the laser beam source onto the slingshot body in order to accommodate variable projectile velocity and the estimated distance to the target in order to improve the target accuracy. Such an improved slingshot would have wide-ranging utility under circumstances in which small animals are the target such as in repelling small animal invasions on farm or home property. Moreover, the accuracy of the system and its capability of firing variable energy projectiles, including non-injurious ones, makes the system suitable in recreational games of skill in which striking moving targets is the objective.  
           [0010]    Laser beam sources in past references have been attached to fire arms, bow and arrow devices and other projectile firing devices to improve target accuracy. However, none of these earlier laser beam targeting devices have been adapted for attachment and use with the unique characteristics of sling shot device.  
           [0011]    Accordingly, it is an object of the present invention to provide a conveniently adjustable laser beam on a sling shot device for improved target accuracy.  
           [0012]    It is an additional object of the invention to provide an elastomeric projectile firing system that uses an adjustable laser-aimed sighting mechanism to increase the accuracy of the system in striking a target with projectiles of variable velocity.  
           [0013]    It is another object of the invention to provide a laser aimed elastomeric projectile firing system in which the mounted laser may be readily adjusted to account for the estimated distance to the target and the predetermined initial velocity of the projectile. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0014]    [0014]FIG. 1 is an elevation view of the side of a preferred embodiment of my invention.  
         [0015]    [0015]FIG. 2 is a cross sectional view taken on plane  2 - 2 .  
         [0016]    [0016]FIG. 3 is a forward or front end elevation view of the of the embodiment of my invention shown in FIG. 1.  
         [0017]    [0017]FIG. 4 is a cross section view of a laser beam source taken on plane  4 - 4 .  
         [0018]    [0018]FIG. 5 is a fragmentary view from below seen from plane  5 - 5  of the adjustably mounted laser beam source.  
         [0019]    [0019]FIG. 6 is a fragmentary plan view of a release mechanism of the embodiment of my invention as illustrated in FIG. 1.  
         [0020]    [0020]FIG. 7 is a cross sectional view taken on plane  7 - 7  of the trigger release mechanism in a cocked ready to fire position.  
         [0021]    [0021]FIG. 8 is a cross sectional view taken on plane  7 - 7  of the trigger release mechanism in a just released fired position.  
         [0022]    [0022]FIG. 9 is a fragmentary perspective view showing component parts of my invention at the instant of release of a projectile. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]    Referring to FIG. 1 showing a side elevation view of a preferred embodiment of my improved sling shot device shows a stock  10  comprising an elongated structure upon which other components of my sling shot are mounted. The stock  10  is formed from a U-shaped member  12  into which an extension  14  is mounted within the U-shaped member  12 . The extension member  14  is secured in the extension of the stock  10  by means of a threaded bolt  16  which passes through one of several possible apertures  18   a , 18   b  in the U-shaped member and a corresponding aperture  20   a , 20   b  in the extension member. The aperture  18   a  in the stock member  12  is threaded on one side. The threaded bolt  16  when fully engaged with the threaded aperture  18   a  will secure the stock members  12  and  14  at a selected extension. As will be described below, elastomers, shown in FIG. 1 at  26  of different length and tension may be accommodated with one or another length of the stock  10 . Thus propulsion elastomers of different tension and different energy storage capacity may be mounted to my slingshot. The velocity of the projectile of my slingshot is determined by the energy stored when suddenly released when my slingshot is discharged. The stock  10  has a forward front end  22  and a rear end  24 .  
         [0024]    A handgrip  28  is securely attached to the rear member  12  and extends below the stock  10 .  
         [0025]    Two brackets  30  and  32  are mounted in parallel relationship to the forward or extension member  14  of the stock  10 . The brackets  30  and  32  extend well above the upper side of the stock  10 .  
         [0026]    [0026]FIGS. 6 and 9 illustrate a molded projectile pouch  34  for holding a projectile  36  preparatory to the release of the projectile. The pouch  34  is secured with small loop elastomers  38 , 40  to a flexible cord  42 . The flexible cord may be formed from woven wires or a woven hemp rope material. The respective ends of the flexible cord  44 , 46  are secured to the respective ends  48 , 50  of the elastomer  26 .  
         [0027]    A trigger assembly  54  is adjustably mounted onto an extension  58  of the stock  10 . The stock extension  58  is positioned on the upper side and at the rear  24  of the stock  10 . The extension  58  is planar, curved, and provides variable vertical and variably rearwardly horizontal means for attaching the trigger assembly  54 . The extension  58  is accordingly provided with spaced indentations  62 , 64 , 66  for attaching the trigger assembly  58 . The horizontal spacing between the indentations  62 , 64 , 66  provides means for lengthening the distance between the brackets  30 , 32  and the trigger assembly  54 , between which the elastomer  26  is suspended in tension ready for discharge by action of the trigger assembly. The maximum tension and therefore maximum energy storage in the elastomer  26  is obtained by positioning the trigger assembly  58  onto the most rearward indentation  66 .  
         [0028]    The trigger assembly  58  is comprised of a cylindrical case  68 . The case  68  may be molded polymer or metal. A moderately hardened flexible rubber retaining member  70  is positioned within the case  68 . Th retaining member  70  is provided with a forward extension  72 , the forward extension  72  is provided with a horizontal recess  74 .  
         [0029]    A trigger  78  is pivotally mounted within the case by means of a pinion  80  slidably assembled in an elongated horizontal opening  82  in the trigger  78 .  
         [0030]    Two metal spheres (ball bearings)  76 , 77  are imbedded in spaced opposition in the walls of the recess  74 . When positioned within the case the recess is narrowed, the metal spheres are forced into contact. The flexible cord  42  is positioned in the recess  74  behind the metal spheres  76 , 74  and thus held in place in preparation for discharge. When the rubber retainer forward extension is forced out of the trigger case  68  the recess  74  is widened, the metal spheres  76 , 77  are separated, and the flexible cord  42  is released.  
         [0031]    A spring  84  placed within the case  68  rearward of the trigger assists the trigger  78  when actuated or pulled to force the rubber retainer member  70  forward and the retainer extension  72  is then forced out of the case. This action is readily seen by observing FIGS. 7 and 8. The trigger assembly  54  includes a handle  86  and a flexible retaining means  88  for adjustably attaching the trigger assembly  54  to one of the indentations  62 , 64 , 66  of the stock extension  58 .  
         [0032]    [0032]FIG. 8 is a cross section view showing at the instant of discharge the positions of the rubber retaining member  70 , the trigger  78 , the marksman&#39;s first finger  90  on the trigger  78 , and the marksman&#39;s second finger  92  on the handle  86 .  
         [0033]    [0033]FIGS. 1, 4, and  5  illustrates the adjustable mounting of a laser beam source  100  positioned at the forward end  22  of the stock  10 . The laser beam source  100  is a small battery powered pencil pointer device available on the market and currently in common use.  
         [0034]    The laser beam source  100  is pivotally mounted in vertically downward extending fitting  102  attached to the lower side of the stock  10 . The barrel of the laser beam source is mounted on a pivot member  104  mounted through an elongated opening  106 . The angle of the laser beam source with respect to the stock  10  is adjustably fixed by means of a threaded bolt  108  threadably engaged in a threaded aperture  110  passing vertically through the rearward section of the laser beam source case  100 . The threaded bolt  108  is secured to the fitting  102  in a freely rotatable mount secured by retainer nuts  112 ,  114 . The angular position of the laser beam source  100  is indicated by the retainer position of the threaded bolt head  116 .  
         [0035]    The following schedules relate to the vertical angle adjustment of the laser beam source with respect to the sling shot stock for the given projectile muzzle or initial velocities and the given distances to the target:  
         [0036]    a) projectile initial velocity 90 miles/hour or 132 feet/second  
         [0037]    distance to target: 200 yards−600 feet;  
         [0038]    time of flight: 4.5 seconds  
         [0039]    calculated vertical deviation from flat or straight line trajectory neglecting friction effects: s=331.24 feet.  
         [0040]    Required angle correction from horizontal 28.9°.  
         [0041]    b) projectile initial velocity 70 miles/hour 102.6 feet/second  
         [0042]    distance to target: 34.2 yards=102 feet  
         [0043]    time of flight: 1 sec calculated vertical deviation from flat or straight line trajectory neglecting friction effects s=32 ft;  
         [0044]    Required angle correction from horizontal arc tan 0.321=17.8° 
         [0045]    c) projectile initial velocity 110 mph=161.3 ft/sec  
         [0046]    distance to target 10 yards=30 feet  
         [0047]    time of flight: 0.18 seconds  
         [0048]    vertical deviation at target from horizontal s=5.76 feet  
         [0049]    required angle correction from horizontal arc tan 0.192=10.9° 
         [0050]    The initial velocity of the projectile is varied depending upon the energy stored in the elastomer  26 . Greater tension in the elastomer  26  achieved by greater expansion (stretching) increases the stored energy available to accelerate the projectile upon release of the elastomer. Typical projectile initial velocities are in the range of 60 miles per hour to 120 miles per hour. Compact dense projectiles for a given initial velocity carry greater momentum (mass times velocity) than less dense projectiles. Accordingly the friction effects will appear to be greater on similarly shaped less dense projectiles i.e. plastic than more dense i.e. metal projectiles.  
         [0051]    The laser beam source fixed to the sling shot stock provides the marksman with a visual straight line of sight marker to the target. By adjusting the elastomer tension and thereby the projectile initial velocity and making an estimate of distance to target the marksman may adjust the angle with the horizontal to compensate for selected projectile initial velocity and distance to the target. Thus the target accuracy of my sling shot may be significantly improved over earlier sling shot devices.  
         [0052]    It is to be understood that the above description is intended to be illustrative and not restrictive. Many other embodiments will be apparent to those skilled in the art. The scope of the invention should therefore be determined with reference to the claims, along with the full scope of equivalents for which such claims may be interpreted.