US3923034A - Slingshot - Google Patents

Abstract

A slingshot including a frame or stock including a fork portion and a handle and a resilient band secured to the fork portion, the band being effectively tapered so as to increase the velocity imparted to a missile and materially increase the efficiency of the slingshot as contrasted to prior art devices having a uniform cross-section resilient band. The tapered resilient band may be cut from sheet material, formed from tubular stock or molded. In addition, the band may be uniformly tapered or non-uniformly tapered, for example, segmented tapered.

Description

United States Patent 11 1 Wolf 11 1 3,923,034 1 1 Dec. 2, 1975 l l SLINGSHOT [76] Inventor: Rodney A. Wolf, 2148 Magnolia Lane, Highland Park, 111. 60035 22 Filed: Sept. 9, 1974 211 Appl. No.: 504,721

Related US. Application Data [63] Continuation of Ser. No. 269,588, July 7, 1972,

abandoned.

[52] US. Cl. 124/20 R; 124/41 R [51] Int. Cl. F418 7/00 [58] Field of Search 124/20 R, 20 A, 20 B, 21, 124/22, 35, 41 R, 16; 24/17 B [5 6] References Cited UNITED STATES PATENTS 118.108 8/1871 Clcaveland 124/20 R 2,079,937 5/1937 Harris 124/20 B 2,600,524 6/1952 Fcrnsel 124/20 R Primary Examiner-Richard J. Apley Assistant ExaminerWilliam R, Browne Attorney, Agent, or FirmSeymour Rothstein [57] ABSTRACT A slingshot including a frame or stock including a fork portion and a handle and a resilient band secured to the fork portion, the band being effectively tapered so as to increase the velocity imparted to a missile and materially increase the efficiency of the slingshot as contrasted to prior art devices having a uniform crosssection resilient band. The tapered resilient band may be cut from sheet material, formed from tubular stock or molded. In addition, the band may be uniformly tapered or non-uniformly tapered. for example, segmented tapered.

16 Claims, 19 Drawing Figures Patent Dec. 2, 1975 Sheet 1 of 2 3,923,034

SLINGSHOT This is a continuation of application Ser. No. 269,588, filed July 7, 1972, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to a slingshot and more particularly to an improved slingshot incorporating novel resilient band means.

Slingshots have been used for many years as hunting weapons and recreation devices. Essentially, a slingshot comprises a stock or frame generally Y-shaped in configuration, having a handle portion and a pair of spaced apart arms forming a fork secured thereto or formed therewith. Resilient band means is secured to the arms, with the center portion of the band means formed as a pocket or being a separate pocket to retain a missile to be hurled.

All prior known slingshots have utilized a resilient band means that is substantially constant in cross-sectional area. In considering ways to improve the efficiency of the slingshot I recognized at the outset certain limitations, for example, the law of conservation of energy must be satisfied. The output of the slingshot is limited by the input and the input is limited by mans size and strength. The input energy is approximately one-half draw times force. Assuming a maximum practical draw of 2 /2 feet and a mazimum practical force of pounds, then the maximum energy input is about 31 ft. lbs. or 43 joules. Recognizing this, it is desired to produce the most efficient resilient band means, one that will deliver the largest fraction of 43 joules. Efficiency is dependent upon the mass of the missile or projectile. The larger the mass, the more energy it can gain. It is desirable that the energy besupplied through a small force over a large distance rather than a large force over a small distance. I have discovered that the major source of energy loss is not friction, air resistance, or inferior rubber. It is an unbalanced ratio of mass to power along the resilient band means. It occurred to me that what was needed was a resilient band that released nearly all of its energy before the pouch carrying the missile reached the slack position. Various forms of resilient band were tried and I found markedly improved results occurringwhen the band was tapered from the frame of the slingshot to the pouch. By tapering slingshot bands the efficiency can increase well above fifty percent.

An object of the present invention is to provide an improved slingshot which incorporates resilient band means that is tapered so as to improve operating efficiency of a slingshot.

Another object of the present invention is to provide an improved slingshot having a frame and resilient band means secured thereto, with the band means being reduced in cross-sectional area away from the connection to the frame toward the pouch which supports a missile to be hurled.

Yet another object of the present invention is to provide an improved slingshot incorporating resilient band means comprised of segmented members, the segmented members closest to the frame having a greater cross-sectional area than the segmented members remote from the frame.

Another object of the present invention is to provide an improved slingshot comprised of segmented members, the segmented members being detachably se- 2 cured to one another by angle pieces generally U- shaped in cross-section.

A further object of the present invention is to provide improved resilient band means for a slingshot. which band means comprises members tapered from one end to the other, the wider end being adapted to be secured to a slingshot frame and the narrower end being adapted to be secured to a missile-retaining pouch.

Other objects and advantages of the present invention will be made more apparent hereinafter.

BRIEF DESCRIPTION OF THE DRAWING There is shown in the attached drawing the presently preferred embodiments of the present invention wherein like numerals in the various reviews refer to like elements and wherein, 1

FIG. 1 is a perspective view illustrating the use of a slingshot having resilient band means made in accordance with the present invention;

FIG. 2 is a side view of a slingshot of the present invention. illustrating the resilient band means untensioned;

FIG. 3 is a side view similar of FIG. 2, illustrating the resilient band means tensioned;

FIG. 3a is a top view of the slingshot of FIG. 3;

FIG. 4 is an elevation view of a modified resilient band means embodying the present invention;

FIG. 4a is a cross-sectional view on an enlarged scale taken along line 4a4a of the band means of FIG. 4;

FIG. 5 shows how the band means of FIG. 4 is made from a single sheet of resilient material;

FIG. 6 is an elevation view illustrating a further modified resilient band means;

FIG. 6a is a cross-sectional view on an enlarged scale of the band means of FIG. 6 taken along line 6a6a;

FIG. 7 is an elevation view of another embodiment of resilient band means;

FIG. 7a is a cross-sectional view on an enlarged scale of the band means of FIG. 7 taken along line 7a7a;

FIG. 8 shows an elevation view of still another modification of resilient band means that includes a web pouch;

FIG. 8a is a cross-sectional view on an enlarged scale of the band means of FIG. 8 taken along line 8a8a;

FIG. 9 illustrates an elevation view of another form of resilient band means also including a web pouch;

FIG. 10 is a front view of a connection clip of the type shown detachably connecting two segments of the resilient band means of FIG. 9;

FIG. 10a is a side view of the connection clip of FIG. 10;

FIG. 11 is a cross-sectional view similar to FIG. 10a of a modified connection clip;

FIG. 12 is a cross-sectional view similar to FIG. 10a of another modification of connection clip; and

FIG. 13 is a cross-sectional view similar to FIG. 10a of yet another modification of the connection clip.

DETAILED DESCRIPTION OF THE PRESENT INVENTION There is shown in FIG. 1 a perspective view illustrating the use of a slingshot 10 made in accordance with the present invention. Basically the slingshot 10 includes frame defining a yoke having a handle portion 12 and a U-shaped portion with a pair of arms 13 and 14 formed integrally with handle portion 12. Resilient band means 15 is secured to the arms 13 and 14 and is adapted to be moved from an untensioned position to a tensioned position. When the resilient band means 15, which is made from rubber or like resilient material. is tensioned and then released the missile 16 which is held in the pouch portion 17 or apex portion of the resilient band means may be released and hurled through the air by the spring forces of the resilient band means 15.

As illustrated in FIG. 1 the right hand RH of the user is adapted to retain the handle portion 12 and the thumb and forefinger of the left hand LH of the user are adapted to engage the pouch 17 to retain the projectile or missile 16 as the resilient band means 15 is tensioned. Upon release of the pouch 17 from the thumb and forefinger of the left hand LH; the missile, which may be a BB. ball or the' like, will be hurled through the air toward the target.

Turning now to FIGS. 2, 3 and 3a there is better shown the construction of the slingshot. The frame or yoke may be fabricated from wood, it may be made from metal suitably formed to desired shape, or it may be molded of plastic material. The resilient band means 15, preferably made from natural rubber, is secured suitably at its ends to the arms 13 and 14 so as to form a generally U-shaped or V-shaped element.

Preferably each side 15a, 15b of the band means 15 has a pouch 17 secured at its end opposite the frame, namely, the smaller end of the side. One method of securing the pouch 17 to each side of the band means would be to slit the pouch, insert the band to be connected to the pouch through the slit and then through the loop of the band. Drawing the band would reduce the loop and form a knotted connection of the side of the resilient band means to the pouch.

In the embodiment of FIGS. 1, 2, 3 and 3a the same looped knot arrangement can be used to secure the bands comprising a side of the band means to one another. Bands 20 and 21 are connected to one another by a knotted loop, as are bands 22 and 23. Bands 20 and 22 are similarly connected to pouch 17. Then band 21 is looped or otherwise secured into the recesses 26, 27 in arm 13 and band 23 is looped or otherwise secured into recesses 28 and 29 in arm 14.

The sides 15a and 15b of the band means 15 are effectively tapered from the connection end to the arms 13 and 14 of the frame 10 to the pouch 17 for containing the missile. By tapering the band means 15 so that the pouch 17 is attached to the smaller end, with the larger end of the side arms being attached to the frame, every part of the resilient band means is more closely matched to its load. Essentially, I have determined that it is important that all parts of the resilient band means be accelerated at the same rate. The closer that the bands are constructed to match the desired acceleration rate, the better all parts will reach slack position at the same instant, and hence there will be maximum efficiency.

Among factors believed responsible for the improved results in slingshot operations and particularly band design are that a lighter missile will travel at substantially the same velocity as a heavier missile. If a B-B were to obtain the same energy as a half inch steel ball it would have to be hurled almost five times as fast. But even with no load, the resilient bands can only obtain their inherent maximum velocity and this velocity is only going to be a little greater than that of the one half inch steel ball. Increasing the tension of the band by increasing its crosssectional area will alter its maximum velocity little. Therefore, since even a thin band will accelerate a small projectile practically to the bands inherent maximum velocity, the thicker or higher tensioned band cannot accelerate it much faster. The energy out put is nearly identical in both cases so that the resilient band with the higher tension is actually less efficient. I have found that the way to obtain a higher velocity is to taper the resilient band from the frame to the pouch. A novel and significant feature of this invention is that the velocity of shortening of a tapered band will exceed that of an untapered band of equal length.

Referring to FIG. 2 there is shown an untensioned band means 15. Comparison with FIGS. 3 and 3a, showing a tensioned band means 15, reveals that there is substantially equal stretching or elongation in both the narrower band and in the wider band. The tapering" or segmented taper of the sides 15a and 1511 enhances materially the function of the band means 15. It will be apparent that the band means 15 can be used to achieve the desired beneficial results with the frame 10 or with a different frame.

Turning to FIGS. 4 and 5 there is shown a modified form of resilient band means 15 that was first used to test the principles of the present invention. A single strip of sheet rubber material was cut in half to form the resilient band means a and 11517. The separate resilient bands 115a and 11511 were connected at one end to the pouch 117 and at the other end to the frame of a slingshot. To a second frame was affixed a resilient band means of uniform cross-section. Such band means was comprised of two bands 115 (not cut in half) with a pouch secured thereto. The second slingshot has a resilient band of conventional design. Band means 115 used one half the amount of rubber in each side arm as compared to a conventional slingshot resilient band means. Under tests utilizing the same frame means, the same tension conditions and the same missile, a B--B was hurled 21 percent faster with the device of FIG. 4 as compared with a conventional resilient band means. The efficiency of the slingshot utilizing the tapered band of FIG. 4 was 240 percent that of the comparable slingshot utilizing resilient band means of constant cross-section over its length. The tapered resilient band means 115 of FIG. 4 required approximately half the stretching energy of the conventional band while at the same time it had a greater energy output.

Other forms of the tapered resilient band means are illustrated in FIGS. 6, 6a, 7, 7a, 8, 8a and 9. In FIGS. 6 and 6a the resilient band means 215 are comprised of separate arm portions 215a and 215b fabricated from a single sheet of resilient material and tapering uniformly from the larger end to the smaller end adjacent the pouch 217. The ends of the band means remote from the pouch can be retained in slits in the frame ofa slingshot, for example, by a retainer or fastener, the ends may be enlarged to prevent them from being pulled from the slits in use, or each free end of the band means may be secured in a slit in the arm of the stock or frame.

In FIGS. 7 and 7a there is shown a further modification wherein the resilient band means 315 is comprised of separate tapered solid members 315a and 315b. The members 315a and 3l5b may be molded or extruded from rubber, synthetic rubber or like material and may be circular, as shown, elliptical, or like shape. In this instance the pouch 316 is not formed from a piece of leather suitably connected at opposite ends to the resilient bands 315a and 31511, rather the pouch 317 is a special pouch comprised of a mesh-like plastic member suitably joined to the side members 315a and 315b, as

for example by separate connectors or connectors molded to the pouch. Alternatively, the smaller ends of the members 315a and 3151; may be slit and the members looped over the pouch to retain same. The pouch est draw forces. The bend in the connector helps to enter the forces and the smaller segment 520, for example, has a tendency to pull toward the center of the connector instead of the edge. The connectors can be could vary in size depending upon the projectile or mis- 5 made from metal or from plastic. sile to be hurled. The web or mesh pouch would be very In FIGS. 11, 12 and 13 there are illustrated modificaflexible and have a minumum of are resistance. The tions of the connector 530. The connectors 630, 730 larger ends of members 315a and 315!) may be suitably and 830 are each U-shaped in cross-section. with FIGS. joined to the frame. For example. solid or tubular studs ll, 12 and 13 corresponding substantially to the crossmay project rearwardly from the frame and engage in section along line 10a10a of FIG. 10. In the embodicomplementary recesses formed in the larger ends of ment of FIG. 11, each arm is generally diamondmembers 315a and 31512. shaped. In the embodiment of FIG. 12, each arm is sub- The embodiment of FIGS. 8 and 8a is like that of stantially in the form ofa cross. In the embodiment of FIGS. 7 and 7a, except that the side members 415a and FIG. 13 each arm is generally elliptical. The use of the 4151) of the band means 415 are formed from tubular 15 connectors 630, 730, and 830 is the same as that of the members rather than solid members. Suitable fabricaconnector 530, namely the strips or bands are stretched tion techniques can be used to form the desired taper, and inserted into the slit of each connector. for example the side members may be molded to de- There has been provided by the present invention a sired shape. The larger ends of the side members 415a novel tapered resilient band for a slingshot that is capaand 415b may engage studs extending from the frame ble of hurling a missile with greater velocity and with or stock to secure the resilient band means to the frame less wasted energy than prior conventional slingshots or stock. having a uniform cross-section resilient band. Basically,

The embodiment of FIG. 9 is comprised of separate the band is tapered so that the pouch for holding a misflat or planar bands 520, 521 and 522, 523 suitably sile or pellet is attached to the small end ofa side memconnected to one another and to the special pouch 517, ber and the larger or flared end of a side member is atmade from mesh-like plastic. The ends of bands 520 tached to the slingshot stock. The resilient band means and 522 may be secured to the pouch by slitting the may have various cross-sectional configurations. For bands adjacent their end and looping an end of each example, it can be rectangular, circular, elliptical or tuband over the end of the pouch and through the slit to bular. By proper tapering, all parts of the band means knot each band upon itself and thereby fasten it to the will reach slack position at the same time and thereby pouch. The bands are fastened to one another by spethe slingshot will attain maximum efficiency. It is within cial connectors 530 which are comprised of generally the inventive concept that the band be of a segmented U-shaped members that are angled as seen in FIG. 9 to taper, that is, that each side member or arm of the resilbetter retain the bands to be joined. The construction ient band means be comprised of separate resilient of the connectors will be considered more fully later. strips or bands connected one to the other, the strips or An advantage of band means of FIG. 9 is that if one bands adjacent the stock being of greater cross-secof the band members 520, 521, or 522, 523 should tional area that those remote from the stock. break, it can be replaced readily without the necessity A number of tests have been made comparing a segfor replacing any of the other members. This advantage mented tapered band (T) and a conventional band (C). is also present in the embodiment of FIGS. 1, 2, 3 and The chart below is a tabulation of the test results ob- 3a in that a single band 20, 21, 22, or 23 can be retained, which shows the marked superiority of the segplaced if necessary. Both of these embodiments (FIGS. mented tapered band (like that shown in FIG. 1) as l and 9) I have called segmented tapered resilient compared with a conventional band of uniform crossbands. section. Ease ratio referred to in the chart below is di- Turning now to FIGS. 10 and 10a there is better illusrectly proportional to the ease of stretching the band trated the connector 530. The connector 530 is very for a given energy out put and is defined as advantageous in the resilient band means construction 515 of FIG. 9 in that it is light, it requires minimum ef- Energy Output in J l X 100 fort to install in order to secure two adjacent overlap- Ease Ram ping strips to one another, it costs little to manufacture,

Steel Ball Max. Draw Draw Force Velocity Energy Efficiency Ease Ratio Diam. Inches lbs. fL/sec. ft.lbs. 7: cm.

T C T C T C T C T C T C 1/4 32 24 19.5 30 345 206 4.5 1.5 17 5 6.7 1.6 3/8 32 24 19.5 30 296 203 10.0 4.7 42 16 16.6 5 1/2 32 24 19.5 30 275 175 20.6 8.4 86 29 34.2 9

and it would not be dangerous to the user ifa strip were to tear or break. As viewed from the front the connector 530 is U-shaped, with a slit 531 between the interconnected arms and base. As seen in FIGS. 9 and 10a the connector 530 is angled intermediate its ends. In use, the two strips or side members to be connected are stretched and slipped into the slit 531. Upon release of the tension in the strips, the friction between the rubber is sufficient to hold the two members even at the high- In working on the design of the taper, I have determined that a continuous taper can be calculated utilizing the formula Y kme' In the formula m equals the mass of the pouch and the pellet; D is the mass per unit area of the sheet rubber (of uniform thickness); and K is a constant.

The K factor increases the slope of a curve on an x-y axis such that if K is greater, so is the energy output. If

the ratio of the largest width to the smallest width is too great however, the band will tear easily. Through tests I have determined that a good ratio is 4, in which case K equals 1.39/Ds, where s is the slack length of the band in centimeters and D is in Gm./cm

While there has been shown'and described presently preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention. Therefore, it is intended in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

I claim:

1. In a slingshot comprising a frame and resilient band means secured thereto, the band means comprising resilient side means and an intermediate missilereceiving portion adapted to retain a missile, the resilient side means being tensioned and then released to fling the missile, the improvement characterized in that the resilient side means are tapered lengthwise substantially along its full length in cross section when untensioned from the connection of the side means to the frame to the connection to the missile-receiving portion to materially increase the velocity of/a missile and the efficiency of the slingshot.

2. A slingshot as in claim 1 wherein the frame comprises a fork member with upstanding arms and the side means is secured to said arms.

3. A slingshot as in claim 2 wherein the side means comprises tapered members, each connected atone end to an arm atthe other end to a pouch adapted to hold a missile.

4. A slingshot as in claim 2 wherein the side means comprises segmented side members, tapering from the connection to the frame to the missile-receiving portion. I

5. A slingshot as in claim l-wherein the resilient side means comprises a pair of bands, and the missilereceiving portion comprises a pouch, each band being connected at one end to the frame and at is opposite end to the pouch, each band tapering in cross section from the frame toward the pouch.

6. A slingshot as in claim 5 wherein each band is rectangular in cross section.

7. A slingshot as in claim 5 wherein each band is tubular in cross section.

8. A slingshot as in claim 5 wherein each band is generally circular in cross section.

9. In a slingshot comprising a frame having a fork member with upstanding arms and resilient band means secured to said arms, said resilient band means comprising resilient side means and an intermediate missilereceiving portion adapted to retain a missile. the resilient side means being tensioned and then released to fling a missile, the improvement characterized in that the resilient side means are tapered lengthwise in cross section from the connection of the side means to a arms toward the missile-receiving portion to materially increase the velocity of a missile and the efficiency of the slingshot, the side means comprising at least two pairs of segmented members, the first member of each pair being of greater mass than the second member of each pair, with the first member of each pair being secured to an arm of the fork member of the frame.

10. A slingshot as in claim 9 wherein the first and second member of each pair is connected by a connector that is generally U-shaped in cross section.

11. A slingshot as in claim 9 wherein each pair of segmented members is connected at one end to the frame and at the other endto a pouch adapted to hold a missile.

12. A slingshot as in claim 11 wherein the pouch is comprised of lightweight web material.

13. Band means for a slingshot comprising resilient side members and an intermediate missilereceiving portion characterized in that the side members are each tapered with reduced cross section lengthwise substantially along its full length in an untensioned condition from the'free ends of the side members toward the missile-receiving portion so as to reduce the mass of the side members from the free ends toward the missilereceiving portion to reduce the draw force necessary to tension the side members while increasing the velocity of a missile to be hurled.

14. Band means as in claim 13 wherein the side members are each comprised of a single resilient strip,

15. Band means as in claim 14, wherein each resilient member is generally circular in cross section.

16. Band means as in claim 13 wherein the side members are each comprised of a pair of resilient members connected to one another.

Claims (16)

1. In a slingshot comprising a frame and resilient band means secured thereto, the band means comprising resilient side means and an intermediate missilereceiving portion adapted to retain a missile, the resilient side means being tensioned and then released to fling the missile, the improvement characterized in that the resilient side means are tapered lengthwise substantially along its full length in cross section when untensioned from the connection of the side means to the frame to the connection to the missile-receiving portion to materially increase the velocity of a missile and the efficiency of the slingshot.

2. A slingshot as in claim 1 wherein the frame comprises a fork member with upstanding arms and the side means is secured to said arms.

3. A slingshot as in claim 2 wherein the side means comprises tapered members, each connected at one end to an arm at the other end to a pouch adapted to hold a missile.

4. A slingshot as in claim 2 wherein the side means comprises segmented side members, tapering from the connection to the frame to the missile-receiving portion.

5. A slingshot as in claim 1 wherein the resilient side means comprises a pair of bands, and the missile-receiving portion comprises a pouch, each band being connected at one end to the frame and at is opposite end to the pouch, each band tapering in cross section from the frame toward the pouch.

6. A slingshot as in claim 5 wherein each band is rectangular in cross section.

7. A slingshot as in claim 5 wherein each band is tubular in cross section.

8. A slingshot as in claim 5 wherein each band is generally circular in cross section.

9. In a slingshot comprising a frame having a fork member with upstanding arms and resilient band means secured to said arms, said resilient band means comprising resilient side means and an intermediate missile-receiving portion adapted to retain a missile, the resilient side means being tensioned and then released to fling a missile, the improvement characterized in that the resilient side means are tapered lengthwise in cross section from the connection of the side means to a arms toward the missile-receiving portion to materially increase the velocity of a missile and the efficiency of the slingshot, the side means comprising at least two pairs of segmented members, the first member of each pair being of greater mass than the second member of each pair, with the first member of each pair being secured to an arm of the fork member of the frame.

10. A slingshot as in claim 9 wherein the first and second member of each pair is connected by a connector that is generally U-shaped in cross section.

11. A slingshot as in claim 9 wherein each pair of segmented members is connected at one end to the frame and at the other end to a pouch adapted to hold a missile.

12. A slingshot as in claim 11 wherein the pouch is comprised of lightweight web material.

13. Band means for a slingshot comprising resilient side members and an intermediate missilereceiving portion characterized in that the side members are each tapered with reduced cross section lengthwise substantially along its full length in an untensioned condition from the free ends of the side members toward the missile-receiving portion so as to reduce the mass of the side members from the free ends toward the missilereceiving portion to reduce the draw force necessary to tension the side members while increasing the velocity of a missile to be hurled.

14. Band means as in claim 13 wherein the side members are each comprised of a single resilient strip.

15. Band means as in claim 14, wherein each resilient member is generally circular in cross section.

16. Band means as in claim 13 wherein the side members are each comprised of a pair of resilient members connected to one another.

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