Spring type projecting device

A slingshot comprises a stock having front and rear ends. A manual gripping handle is disposed at the rear end of the stock. A pair of sheaves are rotatably mounted adjacent the front end and rear end of the stock on opposite sides of the fore-to-aft longitudinal axis of the stock. These sheaves are rotatable about generally upright parallel axes of rotation. An elastic band is provided having outer free ends anchored at points disposed adjacent the rear end of the stock on opposite sides of the fore-to-aft longitudinal stock axis. The elastic band extends forwardly from these anchoring points and is wrapped around the rotatable sheaves. The elastic band includes a pouch capable of carrying an object to be propelled. Upon displacement, the band is stretched in an energy-storing fashion so as to propel the object forwardly upon release. This arrangement provides an inordinately long length of elastic band, thereby increasing the ability of the band to stretch and maximizing its energy-storing capacity. As a result, the velocity of fired projectiles can be significantly increased without appreciably increasing the force required to extend the band, or the length of the stock.

BACKGROUND AND OBJECTS 
This invention relates to a slingshot. 
Slingshot devices for propelling objects have long been known wherein an 
elastic member has its ends anchored to a frame and has a pouch for 
carrying objects to be propelled. Traditionally, these devices have been 
in the form of hand held articles wherein the frame, at its front end, 
includes upright legs to which the elastic member is anchored. A depending 
arm is gripped by one hand of a user and the pouch is retracted by the 
other hand to tension the band. 
Various modifications have been proposed for increasing the accuracy and 
distance of the slingshot, such as the use of an arm brace extending 
rearwardly from the depending arm to provide the shooter with more 
control. Notwithstanding such modifications, though, the distances to 
which projectiles could be fired from slingshots have been severely 
limited. 
It is, therefore, an object of the present invention to provide a slingshot 
which is capable of maximizing the power and distance of object 
propulsion. 
It is another object of the invention to provide such a slingshot in which 
a high degree of accuracy is maintained. 
It is a further object of the invention to provide a novel slingshot 
capable of increasing the velocity of fire projectiles without appreciably 
increasing the stock length or the force required to extend the band. 
BRIEF DESCRIPTION 
These objects are achieved by the present invention which involves a 
slingshot having a stock which includes front and rear ends. A manual 
gripping handle is disposed at the rear end of the stock. A pair of 
sheaves are rotatably mounted adjacent the front end of the stock opposite 
sides of the fore-to-aft longitudinal axis of the stock. These sheaves are 
rotatable about generally upright parallel axes of rotation. An elastic 
band is provided having outer free ends which are anchored at points 
disposed adjacent the rear end of the stock on opposite sides of the 
fore-to-aft longitudinal stock axis. The elastic band extends forwardly 
from these anchoring points and is wrapped around the rotatable sheaves. 
The elastic band includes a pouch capable of carrying an object to be 
propelled. The pouch is disposed for manual rearward displacement in a 
direction parallel to the axis to stretch the elastic band in an 
energy-storing fashion throughout the length thereof so as to propel the 
object forwardly upon release.

DETAILED DESCRIPTION 
In accordance with the present invention, a slingshot 10 includes a stock 
12 having front and rear ends. The stock 12 is preferably fabricated of 
wood, although almost any material may be suitable. Just forwardly of its 
rear end the stock includes a downwardly depending manual gripping handle 
14. Located therebehind is a downwardly depending brace 16 for reasons to 
be discussed subsequently. Fixedly mounted to the stock on opposite sides 
of a longitudinal, i.e., fore-to-aft extending axis through the center of 
the stock are a plurality of front and rear support frames 18F, R. 
Each front support frame 18F comprises a piece of bar stock bent to form a 
front upright section 20, and a front mounting section 22 extending 
perpendicularly from the bottom of the front upright section and being 
fixedly connected to the stock. 
Each rear support frame 18R comprises a piece of bar stock bent to form a 
rear upright section 24 extending parallel to the front upright section 20 
and a rear mounting section 26 extending at a right angle from the bottom 
of the rear upright section and being fixedly connected to the stock. 
The frame 18F, R can be rigidly fastened to metal mounting plates 28 which 
are secured to the sides of the stock 12. 
Suitable bracing struts 32, 34 can be provided to rigidify the front and 
rear upright sections 20, 24. 
A power unit in the form of an elastic band assembly 36 is operably mounted 
to the support structures 18. The elastic band assembly comprises a pair 
of elastic band segments 38 to the outer free ends 40 of which are 
anchored, such as being tied, to the rear upright sections 24. A steel pin 
can be inserted through the band to maintain this condition. Each segment 
38 extends forwardly from its anchored point and is wrapped around a 
sheave 42. Each segment 38 can comprise a section of rubber tubing such as 
surgical hose, for example. 
Each sheave 42 is rotatably mounted to its associated front upright section 
20 intermediate the height thereof. The rotary mounting of the sheave can 
be achieved in any suitable manner, such as by positioning a pair of 
washers 44 on the front upright section 20 above and below the pulley 42 
and retaining the washers in place by tape 46 or the like, as indicated in 
the exploded showing of FIG. 4. 
The inner ends 48 of the elastic band segments are connected to the 
opposite ends of a pouch defining strip 50 preferably formed of leather 
(FIG. 3). More particularly, bifurcated clamps 51 formed of Teflon or 
polyethylene are inserted into slots 52 formed in the pouch 50. The 
elastic band segments 38 are forced over the legs of the clamp as the legs 
of the clamp are squeezed together (FIG. 3). Subsequently, the clamp is 
released, with the legs being biased outwardly into tight gripping contact 
with the inner wall of the tubular band to provide an extremely strong 
connection. If desired, a tubular strip of leather can be applied around 
the band in the region of the clamp to prevent damage if this region of 
the band strikes the sheaves. 
The pouch-defining strip 50 includes a slot 58 located intermediate the 
ends of the strip 50. Fabric may be sewn to the back of the strip so as to 
provide a backing for the slot. Such a slot is of tremendous aid in 
centering a projectile, such as a steel ball for example. Otherwise, the 
ball might have a tendency to wander within the pouch during cocking and 
become disoriented, possibly resulting in a misdirected shot being fired. 
Instead of firing from the pouch, a shooter may desire high accuracy. 
Accordingly, in a modified form of the invention, a firing channel 60 is 
provided in the stock 12 (FIG. 5). This channel is open at its front end 
and is also open along its upper extent 62. A flexible connector, such as 
a string 64 interconnects the strip 50 with a slide 66. The slide 66 is 
sized to slide within the channel 60. The string 64 passes through an 
opening in the slide and can be knotted at its outer end 68 to prevent 
removal of the string from the slide. 
To connect the string 64 to the pouch strip 50, it may merely be tied 
around the latter. 
Attention is directed to copending application Ser. No. 538,802 of the 
present inventor for a more detailed description of the channel and slide 
assembly. 
The slingshot according to the present invention can be fabricated in any 
desired size. One such slingshot has been constructed over four feet in 
length. In order to facilitate transporting of the slingshot, a strap 70 
can be attached to the frame, enabling the slingshot to be carried on the 
back of a shooter. 
The brace 16 can be braced against the body, e.g., the chest, of a shooter 
during firing. To facilitate bracing against the leg, a curved abutment 
knob 72 (shown in phantom lines in FIG. 1) can be added to the brace stock 
16. 
OPERATION 
To propel an object, such as a steel ball, directly from the pouch, the 
ball is inserted into the pouch. The pouch is grasped and squeezed and 
then retracted. The ball remains centered within the pouch due to being 
seated within the slot 58. 
As the pouch is retracted, the elastic band is tensioned and stretched. Due 
to the inordinately long length of the elastic band segments, there is 
inherently present a large capacity for stretching. Thus, a high degree of 
deflection can be obtained resulting in the storage of considerable energy 
within the band. Consequently, the ball can be propelled with high power 
for relatively long distance. 
Elongation of the band is facilitated by the sheaves. That is, friction is 
minimized by rotation of the sheaves, making it easier to tension the band 
with less tendency for frictional wear to occur. 
The result is a long distance, long life slingshot which can be easily 
manipulated by the shooter. For accuracy shooting, the channel-slide 
arrangement of FIG. 5 can be employed in which the projectile, such as a 
ball or dart, is driven by the slide 66 and is guided by the channel 60 
during acceleration. 
As the band is being tensioned, the support structures 18 provide ample 
rigidity for the front upright to prevent deformation thereof. 
The elastic band is subjected to reduced wear as compared with slingshots 
whose band ends are anchored at the front of the stock and which lie slack 
therebetween when in a rest condition. In the case of such slingshots, the 
band, when released, contracts until reaching a forward position; 
thereupon, the slackened band travels forwardly under its own momentum, 
causing the band to turn 180 degrees about the front anchoring points to 
accommodate the further, forward travel. This action, when repeated 
numerous times, has a weakening effect upon the band at the anchoring 
points. No such action occurs in the present invention since the anchoring 
points are disposed at the rear, and since the band, when at rest, extends 
straight, i.e., linearly from sheave to sheave as shown in FIG. 1. Thus, 
when released, the band contracts until assuming the FIG. 1 posture and 
then re-extends slightly. As a result, only slight turning of the band is 
experienced. 
Although the invention has been described in connection with a preferred 
embodiment thereof, it will be appreciated by those skilled in the art 
that additions, modifications, substitutions, and deletions not 
specifically described may be made without departing from the spirit and 
scope of the invention as defined in the appended claims.