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Title:
Tow bar assembly for water-ski towing device
United States Patent 3899993
Abstract:
A water-ski towing device comprising a bouyant hull and a propulsion unit mounted in it. A tow bar extends aft from the transom of the hull for towing a water skier. A compact adjustable mechanism pivotally secures the tow bar to the bouyant hull. The mechanism has a detent to releasably latch the tow bar in an elevated position for operation of the device. An adjustment knob is provided for varying the position of the tow bar in its latched position to accommodate different skier heights or different applications for the device. The tow bar has a pair of hand grips oriented to provide the most comfortable position for an operator's hands and at the same time offer optimum mechanical advantage in steering the vehicle. A throttle and clutch control in the hand grips are finger actuated to improve operator control of the device.


Inventors:
POWERS RICHARD T
Application Number:
05/405896
Publication Date:
08/19/1975
Filing Date:
10/12/1973
Assignee:
POWERS; RICHARD T.
Primary Class:
Other Classes:
441/69
International Classes:
B63B35/73; (IPC1-7): B63B21/56
Field of Search:
115/6.1,70,18E 9
View Patent Images:
US Patent References:
3711755DC FISHING MOTOR SPEED AND STEERING CONTROL1973-01-16Meyer, Jr.
3181493Water sking apparatus1965-05-04Pericut
3062172Motor-driven water ski towing device1962-11-06Moore
2969037Water ski scooter1961-01-24Vogt
2914018Water-borne motor-powered towing device for control by a waterskier1959-11-24Schachner et al.
2853166Solenoid-operated clutch1958-09-23Campbell
Primary Examiner:
Blix, Trygve M.
Assistant Examiner:
Goldstein, Stuart M.
Attorney, Agent or Firm:
Garfinkle, Irwin Gron Gary P. M.
Claims:
Having thus described the invention, what is claimed as novel and desired to be secured by Letters Patent of the United States is

1. A water-ski towing device comprising:

2. A water-ski towing device in claim 1 wherein said mounting means secured to said hull comprises a forked plate including a base plate and a pair of spaced side plates projecting from said base plate and a shaft extending between the free ends of said side plates, said tow bar being pivotally mounted on said shaft;

3. A water-ski towing device as in claim 2 wherein said shaft is releasably secured between said side plates for permitting removal of said tow bar and said latching element.

4. A water-ski towing device as in claim 2 wherein said lever comprises:

5. A water-ski towing device as in claim 4 wherein said L-shaped arms have a bar extending between them and said spring comprises a leaf spring secured to said bar and acting against said base plate to urge said rod into said detent.

6. A water-ski towing device as in claim 1 further comprising adjusting means for adjusting the location of the first position of said tow bar in said vertical plane.

7. A water-ski towing device as in claim 6 wherein said mounting means includes a shaft, said tow bar being pivotal on said shaft, and wherein said adjusting means for adjusting the location of the first position of said tow bar comprises:

8. A water-ski towing device as in claim 7 wherein said means connected between said element and the lower end of said tow bar comprises:

9. A water-ski towing device as in claim 8 wherein said mounting means secured to said hull comprises a forked plate including a base plate and a pair of spaced side plates projecting said base plate, said shaft extending between the free ends of said side plates, and wherein said latching means comprises:

10. A water-ski towing device as in claim 9 wherein said element has a stop against which said rod abuts to limit the downward movement of said tow bar.

11. A water-ski towing device as in claim 10 wherein said shaft is releasably secured between said side plates for permitting removal of said tow bar and said adjustable positioning element.

12. A water-ski towing device as in claim 11 further comprising:

13. A water-ski towing device as in claim 1 further comprising a handle assembly positioned at the end of said tow bar away from said hull, said handle assembly including upwardly extending hand grips oriented substantially vertically as viewed from the side of said device and angled inward as viewed in a fore and aft direction when said tow bar is in said first position.

14. A water-ski towing device comprising:

15. A water-ski towing device as in claim 14 further comprising means for adjustably positioning said tow bar in a vertical plane in said skiing position.

Description:
The present invention relates to water-ski towing devices and more particularly to improvements in tow bars for these types of devices.

In recent years it has been proposed to provide a small bouyant hull with a marine propulsion unit in it and a tow bar extending from the aft end of the hull to a hand grip for towing a water skier. In a number of prior art devices (see U.S. Pat. Nos. 2,914,018 and 3,181,493) it has been proposed to mount the tow bar for free movement in a vertical plane only. This is intended to compensate for the fact that the skier starts out in the water and as the device picks up speed comes out of the water to an elevated planing position. In practice, however, it has proved to be difficult if not impossible to properly operate the water-ski hull, particularly from the standpoint of directional control.

In one instance it has been proposed to permit the handle to swing upward until it reaches a particular elevated position where it is latched in place to function as a fixed element. This greatly enhances the directional control while at the same time permitting the skier to properly ascent to the planing position. One of the problems with this type of device is that the latching mechanism tends to be cumbersome and makes adjustment for individual skier heights relatively difficult.

An additional problem encountered with prior art devices is that the tow bar hand grips are oriented in such a way that they place the skier's hands in uncomfortable positions. Typically, these hand grips are in the form of a T-bar which strains the arm muscles and promotes early fatigue. In addition, the engine controls in these devices are hand grip types that make it extremely difficult to slow the unit down without losing one's grip and falling off. Some of the above problems are solved in accordance with one aspect of the present invention by a water-ski towing device comprising a buoyant hull incorporating a propulsion unit and a tow bar extending in aft direction for operator control. The unit has an adjustable mechanism for mounting the tow bar. The mechanism includes a mounting plate having a base secured to the transom of the hull and a pair of side plates extending aft from the base plate. A shaft extends between the side plates for pivotally mounting the tow bar. An adjustable latching means is positioned substantially between the end plates and releasably latches the tow bar in a predetermined elevated position.

In another aspect of the present invention the above problems are solved by a water-ski towing device comprising a buoyant hull having a propulsion unit and an aft extending tow bar. A handle assembly is secured to the free end of the tow bar and has a pair of hand grips extending substantially vertically upward, as viewed from the side of said device, and angled inward as viewed from a fore and aft direction.

The above and other related features of the present invention will be apparent from a reading of the following description of the disclosure shown in the accompanying drawing and the novelty thereof pointed out in the appended claims.

In the drawings:

FIG. 1 is a simplified external view of a water-ski towing device embodying the tow bar assembly of the present invention; and

FIG. 2 is an enlarged fragmentary sectional view of the water-ski towing device of FIG. 1, particularly illustrating an adjustable latching mechanism for the tow bar assembly;

FIG. 3 is a plan view of the adjustable latching mechanism of FIG. 2;

FIG. 4 is a greatly enlarged view of the handle assembly for the tow bar assembly of FIG. 1; and

FIG. 5 is an end view of the handle assembly as seen from the rear; and

FIG. 6 is a plan view of the handle assembly of FIGS. 4 and 5.

Referring to FIG. 1, there is shown a water-ski towing device comprising a buoyant hull 10 and an upper housing 12 secured at a belt line 14. An engine 16 is mounted within hull 10. As illustrated, the engine is of the outboard type in which the engine output shaft (not shown) is positioned vertically and extends downward through the hull inside of an airfoil strut 17 and into a propeller support housing 18. Housing 18 contains a right angle drive and clutch unit (not shown) that is actuated by a solenoid 19 to connect the engine to a propeller 20. Propeller 20 may be contained within a shroud assembly 22 embodying the features of copending application Ser. No. 403,440, filed on Oct. 4, 1973, and entitled "Propulsion Unit for Water-Ski Towing Device", M. Uroshevich and P. March co-inventors.

Engine 16 is supplied with fuel from a fuel tank 24 and has a ring 26 that is rotated by an electric motor 28 to vary the throttle opening and spark advance for the engine. A battery 30 supplies electrical power for the engine ignition and other control functions, as described later.

One form of marine engine and propulsion has been shown in connection with the description of the present invention. It should be understood that it is for illustrative purposes only and that many other types of engines and propulsion units may be incorporated in the water-ski towing device. The hull 10 has a stern 32 that mounts an adjustable latching mechanism 34 supporting an aft extending tow bar 36 in the form of a tube. Tow bar 36 has a water-skier manipulated handle assembly 38 at its remote end.

Referring to FIGS. 2 and 3 particularly, the adjustable latching mechanism 34 comprises a U-shaped bracket compressed of a base plate 42 secured through the transom 32 of the boat to an internal mounting plate 44 by bolt assemblies 46. Base plate 42 has integral side plates 48 and 50 extending aft.

A shaft 52 in the form of a bolt extends through holes 54 in the side plates 48 and 50 and through the lower end of tow bar 36 for pivotally mounting it to the plates 48 and 50. A nut 56 permits the bolt 52 to be withdrawn from the plates 48 and 50, thereby enabling removal of the tow bar from the hull for storage or transport.

The shaft 52 also pivotally mounts a housing 58 having a socket 60 for receiving the lower end 78 of tow bar 36. Housing 34 at its end away from the pivotal mounting of shaft 52 has a first recess 62 which forms a detent. Recess 62 connects through a smooth cam surface 64 to an additional recess 66 forming a stop for the mechanism. A threaded shaft 68 extends through openings 70 in opposite walls of housing 58 and has a hand-manipulated knob 72 nonrotatably secured to it. Threaded shaft 68 is received in internal threads 74 of a plug 76 positioned in the lower end 78 of tow bar 36.

A latch mechanism 80 comprises a pair of levers 82 and 84 secured to each other through an integral hand plate 85. Levers 82 and 84 are pivotally mounted to plates 50 and 48, respectively, by pins 86. Levers 82 and 84 have arm sections 88. A bar 90 extends between the free ends of arms 88 and is adapted to be received in recess 62 as a detent or in recess 66 to limit downward pivoting movement. A bar 92 is integral with and extends between levers 82 and 84. A leaf spring 94 mounted on bar 92 acts on a ledge 96 protruding from end plate 42 to bias latch mechanism in a counter-clockwise direction about pins 86 as viewed in FIG. 2.

FIGS. 4, 5 and 6 show the handle assembly 38 for the tow bar 36. Handle assembly 38 includes a web comprising upper and lower housings 98 and 100, respectively, having complimentary recesses for receiving the upper end 106 of the tow bar 36. The recesses have inward protruding conical bosses 108 and 110, respectively, received in holes 112 in tow bar 36. Screws 114 extend through openings 116 in the lower housing 100 and are threaded into the conical bosses 108 in the upper housing 98. The central web housing 98 and 100 have additional sockets 118 and 120 which receive tubes 122 and 124, respectively. Pins (not shown) in the sockets 118 and 120 orient the tubes in a particular position. Tube 122 has a hand grip section 126 bent upward in a predetermined relationship, as described later. Hand grip section 126 has a suitable hand grip cover 128. Tube 124 has a hand grip section 130 which is positioned in symmetry with the angle of hand grip section 126. Hand grip section 130 has a suitable cover 132.

Hand grip section 126 has positioned in it a throttle-actuated control device 129 having a thumb-actuated plunger 131. In one form the element 129 is a linear potentiometer and the pin 132 is depressed into the handle to vary the resistance of the potentiometer. In another form device 140 may be a switch to pulse an engine control system. Hand grip section 130 includes a switch 140 having a thumb-actuated plunger 142. Additional switches 144 may be mounted in a plate 146 extending across a recess 148 formed in the upper and lower web housings 98 and 100. Lines 150 extend from switches 144 to a wiring harness cable assembly 152 which extends through a sealed opening 154 in recess 148 to the interior of tow bar 136. Lines 156 and 158 respectively connect devices 129 and 140 to the wiring harness 152.

Wiring harness 152 extends to a point adjacent the lower end of tow bar 36 and out through an opening 160. Harness 152 terminates in a female plug connector 162 interconnecting with a male plug connector 164 molded into the cover 12. A cable assembly 166 extends from connector 164 to an electronic control system 168 (see FIG. 1). From here a line 170 extends to d.c. motor 28 and a line 172 extends to solenoid 19.

As illustrated, element 129 is a linear potentiometer which drives an electronic throttle positioning servosystem to drive the d.c. motor 28 in one direction or another to vary the throttle opening and hence the speed of the engine. Linear potentiometer 129 is biased so that the plunger 131 is fully extended and the throttle ring 26 is in an idle position when there is no pressure on plunger 131. Switch 140 is actuated by depressing plunger 142 to energize solenoid 19 and connect the motor output shaft to the propeller 20 only when the plunger 142 is depressed. The plunger 142 is suitably biased so that in the absence of a pressure on the hand grip the solenoid will not be energized. The remaining switches 144 may be used to provide additional engine controls, such as start, choke and other functions as needed.

As observed in FIG. 4 in which the handle assembly is viewed from the side of the water-ski towing device, the hand grip sections 126 and 130 extend substantially vertically upward when the tow bar is in its elevated latched position. As viewed in FIG. 5, i.e., fore and aft direction, the hand grip sections 126 and 130 are angled inward at an acute angle with respect to the vertical. It has been found that an angle of approximately 27° gives particularly acceptable control.

For operation of the water-ski towing device of FIG. 1 the hand plate 85 is depressed to pivot bar 90 out of recess detent 62 and permit the tow bar 36 to swing downward where its position is limited by the stop 66. In this position the operator can start the water-ski towing using the switches 144 in the web of the handle assembly 38. When the engine is operating the clutch switch 140 is depressed with the thumb of the left hand to interconnect the engine with the propeller 20 and the plunger 142 depressed to open the throttle on the engine and cause the unit to move forward in the water. As the unit gains speed the operator comes up out of the water and begins to plane on his skis. As this happens the tow bar 36 pivots up from its horizontal position to the elevated position shown in FIGS. 1 and 2. At this point, bar 90 snaps into detent 62 by leaf spring 94 and is held in place to secure the tow bar 36 at a preselected elevated position. In this position the tow bar 36 acts as an essentially rigid element for precise and manageable control of the unit.

To adjust for the particular height of the skier with a high degree of precision, the knob 72 is rotated to thread shaft 68 relative to plug 76 and thus cause the lower end 78 of tow bar 36 to move up and down as viewed in FIG. 2. This in turn varied the height of the elevated end of bow bar 36. The above adjustment is made very simply and enables a wide range and very precise selection of the particular height desired.

The position of the hand grips 128 and 132 enables a high degree of control, while at the same time minimizing operator fatigue. This is because the arm muscles are placed in the most natural position for comfortable and prolonged pulling. By separating the holding function and the controlling function, which is done with the thumbs, the possibility of losing one's grip with the remaining fingers when a skier purposefully slows down is minimized if not eliminated. When a skier falls off of the unit the propeller is automatically declutched and the throttle returned to an idle position for safety. To remount, the water skier simply depressed hand plate 85 to place the tow bar 36 in its lower position. The skier is then able to engage the clutch and depress the plunger 142 to open the throttle and again ski.

When the skier is finished the tow bar 36 assembly and the housing 58 can be removed from the mounting plate by undoing nut 56 and pulling out shaft 52. The connector 162 provides a quick disconnect of the wire harness 152 from the cover 12. In this way the overall dimensions of the water-ski towing device are minimized for storage and transport.

The latching mechanism described above is highly compact and fits substantially within the end plates attached to the hull. This minimizes extraneous struts and elements which can get in the skier's way or be damaged. The hand grip assembly enables very precise control of the units using the thumbs and at the same time offers a comfortable position for prolonged skiing activities.

While the preferred embodiment of the present invention has been described, it should be apparent to those skilled in the art that it may be employed in other forms without departing from its spirit and scope.