Safety release for water skiing tow line

A safety release for water skiing tow lines comprising a U-shaped body having a rearwardly facing slot therein, a mounting bracket for securing the device to a ski pylon, a release arm pivotally secured to the body and including a bolt which extends across the slot when the arm is in a vertical position so as to engage the terminal loop of the ski rope. When the arm is pulled forwardly by means of a trip line operated from within the boat, the bolt is retracted out of the slot thereby releasing the tow line. Adjustable spring biased detents are provided for locking the release handle in the open and closed positions.

BACKGROUND OF THE INVENTION 
The present invention relates to a tow line release device and in 
particular to a safety release for water skiing tow lines which is adapted 
for quickly releasing the tow rope upon manual actuation of a trip rope 
from within the boat. 
In many types of water skiing, it is desirable from a safety standpoint to 
be able to quickly release tension on the tow rope should the skier fall. 
In trick skiing, for example, one maneuver includes the placement of the 
skier's foot in the ski rope handle and he is towed without the use of his 
hands. Should the skier fall while in this position, he is susceptible to 
serious leg injuries such as pulled muscles, a twisted knee or a broken 
leg and may even be dragged under water before the driver of the boat 
reacts and is able to stop the boat. Aside from the potential for injury, 
the necessity for the skier to be constantly on guard so that he is able 
to pull his foot out of the handle or tow strap in the case of a fall 
reduces his concentration on performing the maneuver. 
In addition to accidents resulting because of a trick skier being unable to 
release his foot from the rope, many accidents occur as a result of the 
skier becoming entangled in the rope as it is towed from the boat even 
though he has released the handle. Also, in the case where two or more 
skiers are being towed at the same time and one skier falls, the loose 
rope jerks about in the water quite violently and is liable to strike one 
of the other skiers. 
In order to avoid the type of accidents described above, it has been found 
advantageous to provide for quick release of the tow rope by means of a 
trip mechanism operated manually from within the boat. One class of prior 
art devices comprises a pivotally mounted finger which hooks a terminal 
loop in the ski rope and is retained in engaging position by means of a 
latch. When the latch is released, tension on the ski rope pulls the 
finger open thereby releasing the rope. Examples of this type of device 
include U.S. Pat. Nos. 3,110,331; 3,133,521; 52,385; 1,115,807; 3,205,545 
and 2,721,088. 
A disadvantage to this type of device is that the finger requires tension 
on the rope for it to open so that if the ski rope is momentarily slack, 
as is often the case in trick skiing, the finger will fail to open 
quickly. Furthermore, the open finger may present an obstacle which can 
catch the rope and continue to drag the skier. Although the finger in the 
aforementioned U.S. Pat. No. 2,721,088 is designed such that it drops by 
gravity to its open position when released, this renders it inherently 
slow to open in the case of a slack rope. In fact, the rope may even 
interfere with its opening. 
A further example of a prior art tow rope release is shown in U.S. Pat. No. 
3,583,355 which discloses a clamp for gripping the free end of the ski 
rope or bridle. When the release lever is pulled, the jaws of the clamp 
open thereby releasing the tow rope. Due to the fact that the tow rope is 
frictionally rather than positively engaged, it may pull loose during 
skiing, especially if the skier is performing maneuvers which result in a 
high degree of tension being applied to the rope. Furthermore, clamping of 
the rope in this manner is likely to result in premature rope wear. 
A further drawback to pivoted finger type hitches is that the force exerted 
by the tow rope on the finger is in a direction which urges it towards its 
open position. Should the latch mechanism fail, the finger will open 
thereby releasing the rope and causing the skier to fall. Since this is 
most likely to occur when maximum tension to the rope is being applied by 
the skier, as in the case of slalom skiing, the sudden release of tension 
is more likely to cause injury. 
SUMMARY OF THE INVENTION 
The present invention overcomes the above-discussed disadvantages of the 
prior art by providing a release mechanism wherein a terminal loop in the 
rope is positively engaged by a bolt carried by a pivoted release arm. 
When the release arm is tripped, the bolt is positively retracted 
completely out of the loop receiving slot in the body of the mechanism so 
that release time is very short and there are no projections or other 
obstructions to interfere with the release of the rope even if it is in a 
slack condition. 
The bolt and arm are locked in the closed position by means of an 
adjustable spring biased detent mechanism and inadvertent release of the 
rope is impossible, regardless of the degree of tension, because the force 
exerted on the bolt is in a radial direction with respect to the axis of 
rotation of the release arm. This is in distinction to the prior art 
devices wherein one component of the tension force vector is tangential to 
the axis of rotation of the rope engaging finger. 
Specifically, the present invention is a safety release for water skiing 
tow ropes comprising: a body, a mounting bracket for securing the body to 
a towing boat, a rearwardly opening slot in the body adapted to receive a 
loop of rope therein, a bolt extending across the slot and closing the 
same so as to capture the loop of rope received in the slot, and a trip 
lever connected to the bolt for positively retracting the bolt out of the 
slot so that the loop of rope received therein is free to move out of the 
slot in an unobstructed manner. 
It is an object of the present invention to provide a safety release for 
water skiing tow ropes wherein the rope is positively engaged by means of 
a rotatable bolt mechanism wherein the force exerted thereon by the rope 
acts in a direction which intersects its axis of rotation thereby reducing 
the chances of its being forced open. 
Another object of the present invention is to provide a safety release for 
water skiing tow ropes having a rotatable bolt which completely clears the 
tow rope receiving slot upon actuation so that the tow rope is able to 
clear the slot in an unobstructed manner. 
A further object of the present invention is to provide a safety release 
for water skiing tow ropes wherein the rope engaging bolt is locked both 
in its open and closed positions by means of an adjustable detent 
mechanism. 
A still further object of the present invention is to provide a safety 
release for water skiing tow ropes which eliminates the need for the skier 
to concentrate on pulling his foot out of the handle or tow strap if a 
fall occurs thereby permitting him to devote more concentration on the 
performance of the skiing maneuver in question. 
Yet another object of the present invention is to provide a safety release 
for water skiing tow ropes which will release the rope quickly and cleanly 
regardless of whether the rope is taut or slack. 
A still further object of the present invention is to provide a safety 
release for water skiing tow ropes which is adapted to be mounted to a 
skiing pylon and includes an offset trip lever so as to permit 
unobstructed actuation from the front of the towing boat.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings, the release mechanism 10 of the present 
invention is shown mounted to a ski pylon 12 which in turn is mounted to 
the deck, transom, etc. of the towing boat. Mounting is effected by means 
of an arcuate clamping bracket 14 and back plate 16 which are clamped to 
pylon 12 by adjustable clamp straps 18 and 20. Either integrally formed 
with or welded to bracket 14 is a U-shaped body 22. Bracket 14, back plate 
16, straps 18 and 20 and body 22 are preferably made of high strength 
stainless steel so as to resist rusting and corrosion. 
Pivotally mounted within body 22 is a stainless steel release arm 24 which 
has an eye 26 at the lower end thereof adapted to have a trip line 28 
looped therethrough. Arm 24 is connected to body 22 by means of pivot pin 
30 which extends through arm 24 and body 22 and is retained in place by 
means of snap washers 32 and 34. A sleeve 36, which is welded to arm 24, 
is rotatably received over pin 30. Sleeve 36 maintains arm 24 centered 
within body 22 as shown in FIG. 3. The downwardly depending portion 38 of 
arm 24 is offset as shown in FIG. 4 so that it clears pylon 12 when jerked 
rearwardly by trip line 28. This enables the mechanism 10 to be operated 
from the front seat of the boat. 
Body 22 includes a rearwardly opening slot 40 in both sides which is 
substantially coplanar with the axis of rotation of pivot 30 within a 
generally horizontal plane. Because the position at which the rope is 
gripped by the skier is often slightly higher than the release mechanism 
10, this "horizontal plane" may be at a slight angle to the surface of the 
water as shown in FIGS. 1 and 2. Of course, depending on the boat design, 
the angle of the tow rope 42 with respect to the surface of the water may 
vary. For purposes of this description and the appended claims, then, the 
term "horizontal plane" means that plane which is horizontal in one 
orthogonal direction and is defined by the angle of the tow rope 42 when 
tensioned in normal use in the other orthogonal direction. As mentioned 
above, in most cases this plane will be very close to a true horizontal 
plane. 
Slot 40 is provided with edge beads 44 and 46 which protect tow rope 42 
against being frayed or cut by contact with the sharp edges of body 22. 
Bolt means including a cylindrical bolt or pin 48 essentially parallel to 
lever 38 is fixedly secured to arm 24 as by welding and, as shown in FIG. 
1, extends completely across slot 40 when arm 24 is in its closed 
position. When arm 24 is pulled to its open position shown in FIG. 2, bolt 
48 is retracted completely out of slot 40 so that tow rope 42 will slip 
out of slot 40 in an unobstructed manner. It will be noted that bolt 48, 
when in its closed position (FIG. 1), forms an angle of approximately 
10.degree. with the horizontal plane and is tangential to an imaginary arc 
defined about pin 30, which is the axis of rotation of arm 24. Because the 
portion which is engaged by tensioned tow rope 42, slot 40 and pin 30 
being coplanar within the horizontal plane defined by tow rope 42, all of 
the force exerted by rope 42 on bolt 48 is along a direction which 
intersects pivot pin 30. Accordingly, tensioned tow rope 42 exerts no 
rotational forces on arm 24 and the possibility of arm 24 being rotated 
towards its open position by rope 42 is not present. 
A pair of hollow members 50 and 52 are threaded into body 22 in opposing 
relationship and include steel balls 54 and 56, respectively, captured in 
the end thereof. Balls 54 and 56 are urged into contact with arm 24 by 
means of compressed springs 58 and 60 respectively. The tension of balls 
54 and 56 on plate 24 can be adjusted by loosening lock nuts 62 and 64, 
screwing members 50 and 52 toward or away from arm 24 and then 
retightening lock nuts 62 and 64. Arm 24 includes a pair of indentations 
66 and 68 on one side thereof and identically positioned indentations 70 
and 72 on the other side thereof. Indentations 66 and 70 are positioned 
such that they capture balls 56 and 54 when arm 24 is rotated to its open 
position as shown in FIGS. 2, 3, 4 and 5 and indentations 68 and 72 are 
positioned such that they capture balls 56 and 54 when arm 24 is rotated 
to its closed position as shown in FIG. 1. The release tension for arm 24 
may be adjusted by screwing members 50 and 52 toward or away from arm 24 
as mentioned previously. Corners 74 and 76 serve as positive stops against 
bracket 14 in the open and closed positions, respectively. 
In use, arm 24 is pulled forwardly to the position shown in FIG. 2 and the 
terminal loop of tow rope 42 is inserted in slot 40. Arm 24 is then 
rotated rearwardly until balls 54 and 56 are captured in indentations 68 
and 72, and the mechanism is now locked in its closed position. In the 
event the skier should fall or it otherwise becomes necessary to release 
rope 42, trip rope 28 is jerked by the driver or ski watcher thereby 
rotating arm 24 forwardly and retracting bolt 48 out of slot 40. All 
tension is removed from rope 42 and it is free to move out of slot 40. 
While there have been described above the principles of this invention in 
connection with specific apparatus, it is to be clearly understood that 
this description is made only by way of example and not as a limitation to 
the scope of the invention.