US3630165A

US3630165A - Tow for swimmers

Info

Publication number: US3630165A
Application number: US860295A
Authority: US
Inventors: Bernd Bottger
Original assignee: Individual
Current assignee: ARKOS SpA
Priority date: 1968-09-23
Filing date: 1969-09-23
Publication date: 1971-12-28
Anticipated expiration: 1988-12-28
Also published as: AT305115B; GB1216647A; FI51283C; DE1781291A1; NL6914388A; FR2018692A1; NO131876B; DK127230B; SE354967B; NO131876C; FI51283B; BE739272A; CH514345A

Abstract

This invention relates to a tow for swimmers which includes an internal combustion engine carried by a float, the essential novel feature consisting in suspending the engine from underneath the float and providing means for sealing it from the water and supplying combustion air to the engine from the interior of the float which is connected with atmosphere.

Description

United States Patent [72] Inventor Bernd Bottger References Cited UNITED'STATESPATENTS 208 Pinneberg Stettiner Str. 6, Pinneberg,

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TOW FOR SWIMMERS The invention relates to a motor-driven tow for swimmers of the kind having an internal combustion engine which is cooled by the surrounding water, is borne by an air-filled float, drives a propeller and received fuel from a storage tank.

Motor-driven tows of this kind are used for sporting and rescue purposed and are provided at their rear ends with a handle on to which a swimmer can hold and by means of which he can steer the tow.

The known tows of this kind are constructed after the fashion of a boat a substantial part of which extended out of the water. The engine is disposed, either in a watertight interior of a boatlike float or, in the case of a catamaran-type boat, between the two floats, so that it was completely or at least partially sealed off from the surrounding water. In the lastmentioned case the arrangement was such that the water could wash round the engine cylinder casing to cool it.

This boatlike construction of tows has the disadvantage of low degree of stability. Moreover, there are only limited possibilities of arranging the propeller, behind which the swimmer must hold on to the tow.

In order to overcome these disadvantages, which have hitherto impeded the introduction in practice of tows for swimmers, according to the invention the engine is suspended from below the float and draws the combustion air from the interior of the float which is connected to atmosphere.

The engine of the tow according to the invention operates completely under water and produces the propulsion force at a depth which is determined exclusively by the dimensions of the suspension means between the float and the engine and can therefore be freely selected. Moreover, the suspension of the engine below water level renders the tow extremely stable in operation, more particularly since the major part of the float is disposed below the surface of the water.

The float acts not only as a carrier for the engine and the propeller, but also as a fuel storage space and water separator and also as an intake silencer for the combustion air. Preferably the float is connected to atmosphere through a snorkel, and the combustion air intake extends to the top of the interior of the float.

In an advantageous embodiment of the invention, the float and the fuel storage tank are chambers of a hollow member subdivided by a partition. In this way that part of the storage tank which is not filled with fuel boosts the effect of the float and has no adverse effect on tow stability, independently of the quantity of fuel in the tank.

Conveniently, to ensure that the tow is not lost if the swimmer releases his hold when the engine is running, the point of application of the resultant of the resistance of the water lies above the propeller shaft (in whose axis the driving force is produced) during tow operation. As soon as the swimmer released the tow, therefore, it tilts and stays in place (with the propeller disposed in front of I the engine the propeller is lifted out of the water).

In order that the invention may be more clearly understood one particular embodiment thereof will now be described by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a partially longitudinally sectioned side elevation of a tow according to the invention;

FIG. 2 is partly a plan view and partly a horizontal section substantially along the line ll-ll in FIG. 1;

FIG. 3 is a front elevation of the tow;

FIG. 4 is a longitudinal section through the diaphragm chamber of a diaphragm carburetor according to the invention; and

FIG. Sis a section, taken along the line V-V in FIG. 1.

Referring to these drawings, the tow according to the invention comprises an internal combustion engine I having in conventional manner, a cylinder and crankcase 2, a cylinder head 3 and a casing 4, flanged to the cylinder and crankcase 2, for a flywheel with a magneto and an ignition coil disposed in its center. For forward travel (to the left in FIG. 1) the engine output shaft extends through an exhaust chamber 5, described in greater detail hereinafter, and has mounted on its free end a drive propeller 6.

The propeller 6 is enclosed in a substantially cylindrical duct casing 7 having at its water intake end a fixed impeller 8 which serves also as a protection against damage to the propeller and the entry of large foreign bodies. Downstream of the propeller 6 the stream of water drawn in thereby is divided into two streams by the chamber 5 which is acutely angled in plan view, the acute angle pointing in the direction of forward travel (FIGS. 2 and 5). The two streams of water emerge from lateral openings 9 in the duct casing 7.

Attached to the casing 4 at the rear end of the tow is a handle 10 on to which the swimmer using the float holds, the handle 10 transmitting to him the forward driving force of the engine I.

By means of a suitably streamlined hollow shaft ll, which is attached to the duct casing 7 and to a hollow member 12, the engine 1 connected to the duct casing 7 is suspended from a float 13 which forms a chamber of the hollow member 12. Disposed inside the hollow member 12 is a partition 14 dividing the hollow member 12 into two chambers, on of which constitutes the float l3 and the other a storage tank 15 for fuel. 1

Extending into the float 13, which during operation is only slightly above the water level shown in FIG. 1, is a snorkel 16. The air for combustion of the engine is drawn from the inside of the float 13 through an intake pipe 17 extending upwardly and opening adjacent to the top of the inside of the float (FIG. I). The float 13 therefore acts as a separator for any water which may enter through the snorkel l6 and prevents water from entering the intake pipe 17 into the carburetor and the engine combustion chamber.

A carburetor I8. is a diaphragm carburetor whose parts essential for the present context are shown in section in FIG. 4. The space 19 of the diaphragm chamber subdivided by the diaphragm 20 is at the negative intake pressure produced by the engine I; the connection of the space 19 to the engine intake pipe is not shown. A space 21, which is conventionally connected to atmosphere through a bore, but through which water would penetrate in the present case, receives air through a compensating bore 22 connecting the space 21 to the air for combustion duct 23 at a place where there is a lower negative pressure than that in the space 19. If as a result the pressure in the space 21 is lower than atmospheric pressure and compensation cannot be provided by using the backed-up pressure of the flowing air by means of a bend introduced into the air for combustion duct 23, the reduced difference in pressure between the

spaces

19 and 21 is compensated for a larger jet in ajet block 24.

An idling jet needle 25 is helical and has a cylindrical head 26 which extends completely into a bore 27 in the carburetor casing and bears an O-ring 28 which seals off inside the bore 27 the idling nozzle accessible from outside for adjustment purposes from the surrounding water.

A spark plug 29 (FIG. 2) screwed into the cylinder head 3 is connected in conventional manner through an ignition cable 30 to the ignition coil which is disposed inside the case 4. The ignition cable 30 is attached to connection 31 of the spark plug 29. A flexible tube 33, made of watertight material and sealing off the ignition cable 30 and the connection 31 of the spark plug 29 against the surrounding water, is slipped over the insulator 32 of the spark plug 29 concentrically with the ignition cable 30. The tube 33 is suitably attached in sealingtight relationship (not shown) at the introduction of the ignition cable 30 into the case 4. An exhaust bend 34 extends from the cylinder head 3 (FIG. 3) into the chamber 5, which is shown in greater detail in FIG. 5 and forms a part of the exhaust system. The chamber 5 is acutely angled in plan view and divides, as already stated, the stream of water produced by the propeller 6 into two streams which flow over the

chamber walls

35, 36. Extending through the center of the chamber 5 is a sealed welded-in sleeve 37 guiding the drive shaft 38 on which the propeller 6 is mounted.

The chamber wall 36 is provided with an outlet aperture 39 of the exhaust system. When the engine is stopped, the outlet aperture is covered by a dished valve plate 40 of a valve 41. A helical spring 42 bears at one end against an angle member 43, which is attached to the chamber wall 36, and at its other end against the dished valve plate 40 and said spring surrounds and guides the stem 44 of the valve plate 40 and presses the latter resiliently against the chamber wall 36. The pressure of the surrounding water forces the valve plate 40 tightly against the chamber wall, the sealing effect being further enhanced by the fact that the plate 40 is made of plastics and has a wall cross section ending in a point.

As soon as the engine starts, valve plate 40 lifts off the wall 36 of the chamber 5. The opening pressure of the waste gas which can act on the whole inner surface of the valve plate 40, even when the valve is closed, is further enhanced by the fact that the water flowing past is deflected in the zone of the valve 41 more particularly by the angle member 43 and is therefore accelerated, so that a correspondingly reduced static pressure acts from outside on the valve plate 40, due to the increased backing-up pressure,

The intensive cooling of the chamber and therefore of the waste gas therein by the flow of water reduces the volume of the waste gas and enables the outlet aperture 39 to be relatively small and a plastics of satisfactory sealing effect to be used for the valve plate 40.v For the rest the division of the stream of water by the chamber 5 ensures that the swimmer holding on behind the tow is not exposed to the full pressure of the flow of water. Furthermore the swimmer is not troubled by the exhaust gases since they are immediately pulled away by the flow of water passing over the chamber wall 36 and directed away from the swimmer.

The fuel flows from the storage tank through a check valve 45 and a flexible pipe (not shown) to the carburetor l8. Extending into the storage tank 15 is a tube 46 connected to the exhaust system, to produce the necessary pressure equalization above the fuel level in the tank 15. Alternatively, of course, the storage tank 15 can receive air from the intake system, but in that case there is a risk that fuel will enter the intake system and impede the starting of the engine I.

The essential features by means of which all the units of the engine 1 are sealed off independently of one another have been described hereinbefore. It will be self evident that if necessary further means may be provided for sealing the engine from the water, for instance, at the place where the shaft of the throttle valve 47 extends through the wall of the air duct 23 may be provided with sealing means.

I claim:

1. A tow for swimmers comprising, a float, an internal combustion engine carried by said float, a propeller driven by said engine and a fuel tank for supplying fuel to said engine and means are provided for supplying combustion air to said engine from the interior of said float which is connected with at mosphere, and means for suspending said engine from below said float; said suspending means comprising a streamlined hollow shaft connected to the lower side of the float, a duct casing connected to the lower end of said hollow shaftand housing said propeller, and means for securing said engine to said casing downstream of said propeller.

2. A tow for swimmers comprising a float, an internal combustion engine carried by said float, a propeller driven by said engine and a fuel tank for supplying fuel to said engine, wherein said float and fuel tank consists of chambers formed in a hollow member by a partition subdividing the interior of said hollow member and said engine is suspended from below said float, first conduit means providing communicating between atmosphere and the interior of said float chamber, and second conduit means providing communicating between the float chamber and the engine for supplying combustion air to said engine, the first and second conduit means being offset such that the float chamber acts as a separator that prevents water accidentally entering the float chamber from said first conduit means from entering said second conduit means.

3. A tow for swimmers according to cla|m 2, wherein said float chamber is connected to atmosphere through a snorkle that comprises said first conduit means and a combustion air intake comprising said second conduit means extends from the top of the interior of said float chamber.

4. A tow for swimmers according to claim 2, wherein an ignition system, carburetor and exhaust system of the-engine are sealed off independently of each other.

5. A tow for swimmers according to claim 2, wherein a sealed carburetor is supplied with air through a bore extending into a the engine and jet means are provided for compensating for reduced pressure differences.

6. A tow for swimmers comprising a float, an internal combustion engine carried by said float, a propeller driven by said engine and a fuel tank for supplying fuel to said engine, wherein said float and fuel tank consists of chambers formed in a hollow member by a partition subdividing the interior of said hollow member and said engine is suspended from below said float, means being provided for supplying combustion air to said engine from the interior of said float chamber which is connected with atmosphere, and an exhaust system including an acutely angled chamber disposed so as to divide the flow of water into two streams, at least one of the walls of said chamber being provided with a valve having a value plate adapted to be moved into contact with said chamber wall to close an outlet opening therein.

7. A tow for swimmers according to claim 6, wherein a branch pipe extends from the exhaust system into the storage tank above the level of the fuel in said tank.

v, UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,630,165 Dated December 28, 1971 Inventor (s) Bernd BBttger It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

C01. line 5, change "received" to --receives-- Col. 1, line 53, change "released" to --releases-- Col. 2, line 22, change "on" to --one-- I Col, 2, line 51, after "for" insert --by-- Col 4, line 33, after into a" insert "duct for supplying combustion air to-- Signed and sealed this 1'5 th day of July 1972.

(SEAL) Attest:

EDWARD ILFLETCHHLJR. R0 BERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM Po-105O (10-69) USCOMM-DC suave-ps9 UTS. GOVERNMENT PRINTING OFFICE 1 I969 0"355'334

Claims

1. A tow for swimmers comprising, a float, an internal combustion engine carried by said float, a propeller drivEn by said engine and a fuel tank for supplying fuel to said engine and means are provided for supplying combustion air to said engine from the interior of said float which is connected with atmosphere, and means for suspending said engine from below said float; said suspending means comprising a streamlined hollow shaft connected to the lower side of the float, a duct casing connected to the lower end of said hollow shaft and housing said propeller, and means for securing said engine to said casing downstream of said propeller.

3. A tow for swimmers according to claim 2, wherein said float chamber is connected to atmosphere through a snorkle that comprises said first conduit means and a combustion air intake comprising said second conduit means extends from the top of the interior of said float chamber.

4. A tow for swimmers according to claim 2, wherein an ignition system, carburetor and exhaust system of the engine are sealed off independently of each other.