US3344487A - Coupling for release at pre-determined load - Google Patents

Description

J. 1.. DOUTT 3,344,487 COUPLING FQR RELEASE AT FIRE-DETERMINED LOAD Filed April 2, 1965 :NvzN'r-oR Joseph L. DouH e ert inc'rllnadw Lift?" 3,344,487 COUPLING FOR RELEASE AT PIKE-DETERMINED LOAD Joseph L. Doutt, Box 335, Wampum, Pa. 16157 Filed Apr. 2, 1965, Scr. No. 445,128

Claims. (Cl. 24-201) This invention relates to cogpli gg s for transmitting ,rirr: w tcnsi e loads an'tl'WliiCfi are d signed to sepa ate ata prg M. m s J jhescctu lina The invention is particularly useful fci'fwater skiing and the like in which it is desired to have acoupling which will transmit a force adequate to tow the skier in normal position, but which will release if an unexpected additional strain is placed upon tfie tow rope.

7T tow ro e for water skiing ordinarily comprises a single line WlllCh extends rearwardly from the boat to a point from which two lines diverge to opposite ends of a tow bar. The two lines diverging from that point and the tow bar generally form a triangle when seen from above. The skier holds the tow bar and is thereby pulled in a forward direction through the water.

Water skiing has become an increasingly more popular sport in recent years. As the popularity of the sport has increased, it has also become more common to use boats having larger engines and to engage in acrobatics upon water skies. Such acrobatics, or stunt skiing, commonly involve riding upon one ski or using one hand or one foot to hold the tow rope. At those times, water skiers frequently step over the tow rope while moving, as well as performing various jumps and changes of position.

In the course of stunt skiing, the chances of a spill or Sometimes the skier is upset and concurrently hasa hand urn not" 05v Hutu .1 nd. v are.

.or leg caught between the tow bar and one of the ropes.

The resistance offered by the skier in the water is, of I in a tow rope by uncoupling the tow bar from the boat 3,344,487 Patented Oct. 3, 1 967 springably embraced between the separated branches of thebifurcated member. In the preferred form of my invention, the' bifurcated member is formed of spring-like material and carries opposed non-planar pads or surfaces at the ends of the separated sections. The second tension member, which is preferably in the form of a spool and.

has non-planar faces having a configuration disposed to .cooperate with the non-planar faces upon the pads, is fitted between the pads and is springably embraced between the arms of the bifurcated member. I preferably employ pads upon the ends of the bifurcated arms. which pads have convex surfaces. I further prefer that the spool member have cooperating concave faces which engage the convex faces. I

Other details, objects and advantages of my invention will become more apparent as the following description of a present preferred embodiment thereof proceeds.

In the accompanying drawings, I have illustra'ted'a present preferred embodimentof my invention in which:

FIGURE 1 is a side view, taken in section, of a coupling embodying my invention used in a water ski tow rope;

FIGURE 2 is a plan view, taken'in section, of the coupling illustrated in FIGURE 1;

FIGURE 3 is an end view of the coupling illustrated in FIGURE 1;

FIGURE 4 is a view of the opposite end of the coupling shown in FIGURE 1; and

FIGURE 5 is a sectional view taken along line V--V of FIGURE 1.

The cou'gling includes-a gene ally lipdrical tube 1.

- Tube 1 is formed of several parts includinghfi'ifih'e'i' in e 2 and an outer tube 3. A tubular section 4 is preferahiv fitted between tubes 2 and 3. Tubular member 4 is prefer ably of wood or some other buoyant material and is sheathed in metal such as aluminum or the like to increase the life of the coupling. Tubes 2 and 3, of course, constitute the sheathing. The inner diameter of the entire cylindrical tube 1 is reduced to a smaller inside diameter at one end. I

A slidably movable rod 6 is fitted within the section 5 of smaller diameter. One end of rod 6 has an enlarged before a dangerously high tension in the tow rope is reached.

I provide a body member having a recess or opening therein. I preferably employ a tubular body member having a bore therein. I further provide a bifurcated member slidably positioned within the opening or recess within the body member, whereby varying lengths of thebranches of the bifurcated member may be positioned within the recess or projecting outside the recess. I prefer to provide a cylindrical tube into which the bifurcated member is axially siidable. I further provide detent means operable between the body member and the bifurcated member to lock them in desired relative position. I also prefer to provide a tension member adjustably positioned within the bore of the tubular member and connected to the bifurcated member. The tension member is connected to one of the lines which is to be connected. The tension member is preferably notched or grooved for reception of detent means thereby holding the bifurcated member in position. I further prefer to provide stop I means adjustably positionedupon the tension member to limit sliding movement of the tension member and of the bifurcated member.

I further prefer to provide second tension members diameter or shoulder 7 which is larger than the inner d1ameter of cylindrical tube -1 at section 5. The shoulder section 7 is positioned .within the section of larger diameter of cylindrical tube 1. Tube 1 is slidablc along rod 6. The other end 8 of rod 6 is external to tube 1. A bracket 9 is fastened to end 8 of rod 6 by two screws 10. The central portion of rod 6 has a number of circumferential grooves 11 formed within it. Inner sheathing tube 2 extends outwardly at the rod end of the coupling and has two cylindrical bores 12 within it. A coilspring 13 and a ball bearing 14 are fitted within each of cylindrical bores 12. The springs 13 press ball bearings 14 into grooves 11.

Rod 6 is bored inwardly from its small end 8 forming a hole 15, into which a rope 16 is inserted. Rope 16 is locked into place within hole 15 by screws or by knotting the end of the rope or the like. Any convenient manner of fastening may readily be used. The fastening has not been shown in further detail in the drawings to enablethe invention to be shown more clearly.

The end of rod 6 having shoulder 7 has a counterbore 17 drillc axially into it. A pin 18 extends transversely through rod 6 and through the counterbore. A bifurcated spring 19, which includes a loop 20, is inserted into the counterbore. Spring 19 di 'cs at its end remote from loop 20 into a wish bone c having arms 21 and 22. By sliding tube 1 over red 6, the ends of arms 21 and 22 may be disposed within the bore of tube 1 or outside or" tube 1. A pad 23 is fastened to the inner end of each of arms 21 and 22 by a screw 24. A spool 25 is fitted between pads 23. As will be seen from the drawings, the inwardly a? is.

ing arms 21 and 22. An eye 26 having an opening 27 is formed on one side of spool 25. Spool 25 thereby transmits tension from a rope or the like through eye 26 to the rest of the coupling.

A thumb screw 28 is rotated into bracket 9 on an axis parallel to rod 6. Thumb screw 28 comes into contact. with the end of tube 1 and serves to limit further movement of rod 6 into tube 1.

In use. till coupling is preferably laceg atlmw emf thetow rope and just aheadgj tl e tpgy bar in easy position to be reached bylhe water skier. Rod 6 is preferably connected to the rear end of the tow rope 16 and the two lines which connect to the ends of the tow bar preferably extend rearwardly from eye 26. Towing is customariiy commenced with the skier in the water. When the boat is started, there is a substantial drag until the 2 "to thetime towing begins, thereby bringing shoulder 7 of rod 6 against the section of reduced inner diameter 5 of tube 1. At that time, arms 21 and 22 of spring 19 are completely contained within tube 1. It is impossiblefor them to spread apart and spool 25 is thereby firmly locked between pads 23. After the skier has reached skiing position, he slides tube '1 rearwardly over tube 6 until a desired length of arms 21 and 22 projects out of the end of tube 1. When the ends of arms 21 and 22 do project out of tube 1, the application of enough tension upon rope 16 and eye 25 will tend to cause spool 25 t be p lled from between pads 23, thereby forcing the ends of arms 21 and 22 apart. When the tension exceeds some pre-determined amount, spool 25 will be released, thereby permitting the boat to proceed without the skier. Such a-situation will occur if the skier falls into the water but continues to hold onto the towbar or becomes entangled in it.

It is, of course, apparent that skiers. of heavier weight will require a greater force for proper towing. Accordingly, the relative position of rod 6 and tube 1 may be adjusted for skiers of different weights. In like fashion, acrobatic skiing may require more force than ordinary towing. The greater the length of spring 19 which projects out of tube 1, the less force will be required to separate the pads 23. Accordingly, rod 6 is adjusted relative to tube 1 until ball bearings 14 are in the desired groove 11 to provide just enough force for proper towing without permitting uncoupling. It will be apparent that the proper position will vary for different weights and different styles of skiing.

After'a desired position has been established, thumb screw 28 may be adjusted until it abuts the end of tube 1. Thereafter, when it is desired to start from a rest position, tube 1 may he slid over tube 6 to locked position until the skier reaches skiing position. He can then slide tube 1 forwardly until further movement is stopped by thumb screw 28. In this manner, the same adjustment can repeatedly be made without the necessity of counting clicks as ball bearings 14 drop into successive grooves 11.

Since cylindrical tube 1 is made of light weight materials, at least some of which are buoyant, it will float upon the water and will not drag the end of tow rope 16 to the bottom. When the coupling parts, tube 1 can readily be recovered and spool 25 be reinserted in position for a new start.

The coupling is preferably connected to the tow rope just forward of the tow bar and within easy reach of the water skier. It can, however, be placed at the boat end of the tow line, if desired, in which case the operator facing surfaces of pads 23 are convex, and the outer faces of spool 25 are concave. In this mannenspool 25 is held between pads 23 and may be withdrawn only by spread- 4 of the boat must also adjust the coupling, by the use of a slidable control, that would be attached to cylindrical tube 1. v

While I have illustrated and described a present preferred embodiment of my invention, it is to be understood that I do not limit myself thereto, and that my invention may be'otherwise variously practiced within the scope of the following claims.

I claim:

1. A tension coupling for release at a pre-deterni ip ed load comprising a body member, a resilient bifurcated member having a pair of arms extending from a common single end, the exterior surfaces of the opposed ends of said arms being spaced apart a distance at least equal to the inside diameter of the tubular body member, said bifurcated member being slidably positioned within a reccss in the body member, a first tension member adapted to extend into the body member and connected to the single end of the bifurcated member, position holding means extending between the body member and the first tension member and in operative relationship between the body member and the bifurcated member whereby the bifurcated membermay be axially positioned relative to the body member as desired from a non-release position in which the ends of the arms of the bifurcated member are contained within the body member to a'position capable of releasing a load at a selected load level in which Am" idu-ln .vi 9% t c Cuuuuou sin cuu, A3 exterior s :faces of the oppmed ends of said branches being spaced apart a distance at least equal to the inside diameter of the tubular body member, said bifurcated member being slidably positioned within the tubular member, a first tension member adapted to extend into the body member and connected to the single end of the bifurcated member, detent means on the tubular member engageable with recesses in the first tension member and controllably positioning the tubular member relative to the first tension member and the bifurcated member from. a locked position in which the ends of the branches of the bifurcated member are disposed within the tubular member to an unlocked position in which the said ends are disposed without the tubular member, a second tension member, second tension member engaging surfaces formed upon the branches of the bifurcated member, and non-planar cooperating surfaces formed upon the second tension member and arranged to cooperate with said surfaces on the branches of the bifurcated member whereby the second tension member may be springably clamped between branches of the bifurcated member.

3. A tension coupling for releaseat a pre-determined load comprising a body member, a resilient bifurcated member slidably positioned within a recess in the body member, non-planar surfaces formed upon the ends of the branches of the bifurcated member, a first tension member adapted to extend into the boy member and connected to the single end of the bifurcated member, a second tension member having non-planar surfaces arranged to cooperate with the non-planar surfaces of the bifurcated member, whereby the second tension mem ber may be springably clamped between the branches of the bifurcated member, r. sent means on the body member engageable with recesses in the first tension member coniiollubly positioning the body member relative to the first tension member and the bifurcated member, whereby the ends of the branches or" the bifurcated member may be disposed from a position within the recess in the body member therebypreventing release of V the second tension member from its position between its position between said branches, and stop means ad-' justably fitted to the first tension member and disposed to contact the body member whereby movement of the first tension member relative to the body member is limited.

4. A tension coupling for release at a pre-dctermined member slidably positioned within the tubular member, convex surfaces formed upon the ends of the branches of the bifurcated member, a tension member adapted to extend into the body member and connected to the single end of the bifurcnetd member, a spool member having concave end surfaces arranged to cooperate with the convex surfaces of the bifurcated member whereby the spool member may be embraced between the branches of the bifurcated member, detent means on the tubular member engageable with recesses in the tension member controllably positioning the tubular member relative to the tension member and bifurcated member whereby the ends of the branches of the bifurcated member may be disposed from a position within the tubular member thereby preventing release of the spool member from its position between said branches to a position without said tubular member thereby permitting release of the spool member from its position between said branches under a load, and stop means adiustably fitted to the tension member and disposed to contact the tubular member whereby movement of the tension member relative to the tubular member is limited.

5. A tension coupling for water skiing adapted to release a tow bar from a boat at a pre-determined load comprising a tubular body member, a resilient bifurcated 1 load comprising a tubular member, a resilient bifurcated m 6 1 member slidably positioned within a bore in the tubular body member, convex branchesv of the bifurcated me her, a tension member adapted to extend into the tubular body member and connected at one end to the Single end of the bifurcated member and connected at the other end to one-of the boat and tow bar, a spool member having concave end surfaces arranged to cooperate with the convex surfaces of the bifurcated member whereby the spool member may be embraced between the branches of the bifurcated member, said spool member being connected to the other end of the boat and tow bar, detent means on the tubular body member engageable'with rew cesses in the tension member controllably-positioning the tubular member relative to the tension member and the bifurcated member whereby the ends of the branches of the bifurcated member'may be deposed from a position within the tubular member thereby preventing release of the spool member from its position between said branches to a position without said tubular member thereby permitting release of the spool member from its position between said branches, and stop means adjustably fitted to the tension member and disposed to contact the tubular member whereby movement of the tension member relative to the tubular member is limited.

References Cited UNITED STATES PATENTS 1,409,776 3/1922 Randall 280-450 1,434,931 11/1922 Tucker 280449 2,583,680 1/1952 Brennan 24-26O X 2,654,135 10/ 1953 Grizzard. 3,083,992 4/1963 Pos. 3,171,183 3/1965 Johnson.

BERNARD A. GELAK, Primary Examiner.

Claims (1)

1. A TENSION COUPLING FOR RELEASE AT A PRE-DETERMINED LOAD COMPRISING A BODY MEMBER, A RESILIENT BIFURCATED MEMBER HAVING A PAIR OF ARMS EXTENDING FROM A COMMON SINGLE END, THE EXTERIOR SURFACES OF THE OPPOSED ENDS OF SAID ARMS BEING SPACED APART A DISTANCE AT LEAST EQUAL TO THE INSIDE DIAMETER OF THE TUBULAR BODY MEMBER, SAID BIFURCATED MEMBER BEING SLIDABLY POSITIONED WITHIN A RECESS IN THE BODY MEMBER, A FIRST TENSION MEMBER ADAPTED TO EXTEND INTO THE BODY MEMBER AND CONNECTED TO THE SINGLE END OF THE BIFURCATED MEMBER, POSITION HOLDING MEANS EXTENDING BETWEEN THE BODY MEMBER AND THE FIRST TENSION MEMBER AND IN OPERATIVE RELATIONSHIP BETWEEN THE BODY MEMBER AND THE BIFURCATED MEMBER WHEREBY THE BIFURCATED MEMBER MAY BE AXIALLY POSITIONED RELATIVE TO

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