1. Field of the Invention
The invention relates generally to a retracting reel and in particular to an automatic diving tending system, where the system facilitates elimination of slack in a tending line, therein helping a diver with underwater communication.
2. Background
Automatic tending systems for lines have been reported in the literature, where the system includes a reel with a ratcheting means. The ratcheting means typically has a rotatable ratchet that includes a round gear with teeth, and a spring-loaded pawl on a pivot axis that engages the teeth. The teeth are uniform but asymmetrical, with each tooth having a moderate slope on one edge and a much steeper slope on the other edge. The spring-loaded pawl enables the round gear to turn in one direction, with the pawl riding over the moderate sloped edge, but not turn in the opposite direction. The spring-loaded pawl will catch against the steeply sloped edge of the first tooth it encounters, thereby locking it against the tooth and preventing any further motion in the opposite direction. Typically the pawl engages the rotating ratchet to prevent unwind of line.
Typically, the spring attached to the pawl is a tension spring, and it is stretched to its greatest tension every time it passes over a tooth's tip. Most ratchets generate an audible “click” when the pawl passes a tooth. The “click” is the sound generated when the pawl snaps into the notch between a pair of teeth on the round gear. Underwater the “click” sound may be heard by sonar and even other divers over significant distances.
The rotatable ratchet is typically used to prevent a line from being pulled off a reel, or in the case of fishing reels, only being pulled at a tension that is less than the tensile strength of the line.
Since the rotatable ratchet can only stop motion at discrete points (i.e., at tooth boundaries), the rotatable ratchet does allow a limited amount of backward motion. This backward motion is limited to a maximum distance, that is, about equal to a width of the notch between the teeth, and in some circles is called the backlash or play. The prior art teaches that in cases where backlash or play must be minimized, a smooth, toothless ratchet with a high friction surface such as rubber is sometimes used. The pawl bears against the surface at an angle so that any backward motion will cause the pawl to jam against the surface, and thus prevent any further backward motion. Since the backward travel distance is primarily a function of the compressibility of the high friction surface, this mechanism may result in significantly reduced backlash or play, but at the expense of reduced torsional locking strength.
A first object of the invention, an automatic diving tending system, is that the system utilizes very little energy. The system includes a tether spool apparatus onto which is wound the line, and the spool is fitted onto a torsional apparatus that includes a spring motor. The spring motor provides torsional energy for rewinding the line. The torsional energy is regenerated as line is pulled off the tether spool and the regenerated torsional energy is stored on the spring motor. The spring motor provides a structure for the system to conserve energy, and maintain a nearly constant torque.
A second object of the invention is that the system enables the tether spool apparatus to be swapped out with another tether spool apparatus if the tether spool apparatus becomes fouled, for example with jelly fish, detritus, knots, or normal wear and tear in an aquatic environment.
A third object of the invention is to provide a locking mechanism to stop the rewind of the line, where a diver can stop the up-take of line, and/or restart the up-take of slack in the line. The locking mechanism also may provide a communication structure with other divers and personnel on the surface.
A fourth object of the invention is to reduce the audible “clicking”, by using a static ratchet in the locking mechanism, where the “clicking” is nearly eliminated, and is certainly less than a conventional ratchet. The invention isolates the clicking sound in an air and water tight cavity in the torsional apparatus that largely remains on the surface of the water. The audible “clicking” is nearly silent and therefore much more difficult to detect as air is a poorer conductor of sound than water, and the torsional apparatus is sealed.
A fifth object of the invention is that the automatic diving tending system may function without the use of electricity. Electricity introduces the possibility of shock and accelerates corrosion, especially in a salt water environment.
A sixth object of the invention is to reduce backlash or play.
The foregoing invention will become readily apparent by referring to the following detailed description and the appended drawings in which:
The automatic diving tending system (ADTS) provides a line that is readily available. The line is retractably wound onto a tether spool. The system eliminates excess slack and reduces fouling of lines that accompany slack lines. The ADTS may maintain a near constant tension, therein making it possible to communicate using line pull signals.
The ADTS 10 is shown on its side in
The cavity of the buoyant sealed torsional apparatus 50 includes a cover 52 with a perimeter flange 54, which is affixed to a perimeter seal 62 of a plate 60 made of a corrosion resistant material, such as stainless steel. Mounted on the plate 60 is a bridge 66 (see
Returning to
A gear wheel 86 is flush mounted to the take-up reel 82b, which in turn through an overdrive transmission linkage (not visible) is connected to the drive shaft 64, which is connected to the spool 22.
Pulling line off the spool 22 forwardly rotates the drive shaft 64, which causes the recoil spring 84 to be wound on the take-up reel 82b, storing energy in the recoil spring 84. If the pulled off line is released, then the recoil spring initiates retraction, reversing the direction of rotation of the drive shaft 64, unless the drive shaft is locked. As the recoil spring returns to the unwind reel, the the direction of rotation of the reels and the spool is also reversed. There is enough recoil spring energy to retract all the line pulled off the spool back onto the spool 22.
The spool 22 is an element of the tether spool apparatus 20. The spool 22 includes a spool shaft 24 having a mounted pair of spool walls 26a,26b, and a top-side axial connecting structure 23 (see
The frame 28 provides a structure to change out a spool if the line becomes fouled, for example with jelly fish, detritus, knots, or normal wear and tear found in an aquatic environment.
Torsional energy is conserved in the spring motor 80. As previously described, as line is pulled off the spool 22, the spool 22 turns, which in turn winds the recoil spring onto the take-up reel 82b through the drive shaft 64 and the overdrive transmission linkage. When line is retracted onto the spool 22, the rewind energy is provided by the constant torque spring motor 80 as spring energy is in the recoil spring wound backwards on the take-up reel.
The rate of retraction is dependent on a number of factors, including the length and size of the line, the weight and resistance to flow of water around any elements attached to the line, the characteristics of the spring motor and the gearing ratio of the overdrive transmission linkage. Generally, for every twelve inches (i.e. one foot) of line that is rewound onto the spool, about 1 to 3 inches of recoil spring will rewind onto the unwind reel 82a. From the perspective of the spring motor, this ratio is an overdrive ratio overdrive of the recoil spring length to the line length of about 1:12 to about 3:12. If the tension on the line is about 2 to 6 pounds, and the ratio of line to recoil spring is about 10, then the tension on the recoil spring is 20 to 60 pounds, not accounting for any frictional loss of the spring, transmission, drive shaft and bearings. For a diver, the tension on the line is nominally about 5 pounds or less.
As illustrated in
The invented ADTS includes a locking mechanism 90 to stop and start rewind of line as indicated in
The static ratchet 92 is mounted on the bearing 70 mounted on the bottom 68 of the plate 60 using screws 93 (
The rotor 94 includes a length that is sufficiently long enough so that the centrifugal pawls 96a,96b are far enough from the drive shaft 64. Accordingly, the drive shaft does not have to reach very high rpms before the centrifugal force will be strong enough to overcome a countervailing force exerted by the coiled wire springs thus preventing the pawls 96a,96b from impinging the asymmetrical gear teeth 91 of the static ratchet 92. As can be easily seen in
The coiled wire spring 95,95′ is coaxial with the pivot hole 96ap,96bp. The coiled wire spring 95,95′ has a longer section of straight wire 95s1,95s1′ that is positioned against the pinion 96p,96p′ mounted in the holes (a first hole 96a1 is shown in
The pair of pawls not only mechanically balance the rotor but double the chance of a fast successful engagement with the static ratchet producing a stop. This configuration further reduces backlash or play.
The locking mechanism is locked by jerking on the line then relaxing it. The jerk increases the rpm of the drive shaft and the rotor enough so that the generated centrifugal force on the pawls exceeds the countervailing force, therein individually actuating the wedge of the pawl to pivot inward into the nearest notch between the asymmetrical gear teeth on the static ratchet. The actuation stops rotation of the drive shaft and everything connected to it (including the spool, the rotor, the reels on the spring motor and the tending line). After the jerk, the rewind tension stored in the spring motor keeps the pawls pressed against a steeply sloped edge of the asymmetrical tooth of the static ratchet. This configuration prevents the pawls from pivoting back to their default unlocked position (shown in
The locking mechanism is unlocked by jerking on the line again, enabling rewinding to continue. The jerk causes each engaged pawl to back away from the steeply sloped edge of the asymmetrical tooth of the static ratchet. The jerk further allows the pawls to pivot, springedly, away from the static ratchet back to their default position.
Pulling steadily on the line, without the second jerk, may result in submerging the ADTS, depending on its buoyancy. Once the line unwind tension is high enough to overcome the rewind tension, the locking mechanism will unlock.
In general the tending line may be used to communicate to other divers along the tending line, as the line normally has little slack. The locking mechanism enables the use of line pull signals to communicate, clearly, with surface personnel as well as to control the rewind.
Finally, any numerical parameters set forth in the specification and attached claims are approximations (for example, by using the term “about”) that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of significant digits and by applying ordinary rounding.
The invention described herein may be manufactured and used by or for the Government of the United States of America for Governmental purposes without the payment of any royalties thereon or therefore.
Number | Name | Date | Kind |
---|---|---|---|
5173067 | Biba | Dec 1992 | A |
5938140 | Fundak | Aug 1999 | A |
7455257 | Kaleta | Nov 2008 | B1 |
8336688 | Chen et al. | Dec 2012 | B2 |
20170211318 | Chen | Jul 2017 | A1 |