NZ529127A

NZ529127A - Marine propulsion device

Info

Publication number: NZ529127A
Application number: NZ529127A
Authority: NZ
Inventors: Robert Allen
Original assignee: Robert Allen
Priority date: 2001-03-27
Filing date: 2007-01-16
Publication date: 2007-05-31
Also published as: AUPR400601A0; WO2002076822A1; US20040092176A1

Abstract

A device for adapting a brush cutter or whipper snipper to perform as a marine propulsion unit is disclosed. The brush cutter or whipper snipper must have an engine driving a first shaft (2) rotatably mounted within an outer shaft. The device includes a two or three bladed propeller with low pitched blades (5) connected to a second shaft (4), and a propeller housing that supports the second shaft. A set of brass drive inserts (6-8) of particular shapes are used to connect the first and second shafts to allow the propeller to be driven by the engine. The propeller can be used for propulsion of a small watercraft.

Description

<2 1 MARINE PROPULSION DEVICE FIELD OF THE INVENTION The present invention relates to a quick release marine propulsion device that will adapt onto whipper snippers or brush cutters. Once assembled, it can thai be mounted onto or into small watercraft for propulsion through water.

BACKGROUND OF THE INVENTION The standard outboard motor is widely used for marine or riverine propulsion. However, when all that is required is some lightweight and inexpensive propulsion means to propel a boat, or some other marine craft, relatively short distances, the purchase of an outboard motor is often an expensive option.

For example, owners of yachts or similar vessels who must moor their vessel in deep water use some form offender to access their moored vessel. At present, the tender used can be an oar propelled rowing boat or powered by an outboard motor. Upon reaching the moored vessel, the tender is attached to the mooring to prevent it drifting away. When an outboard motor is used to propel the tender, the outboard motor is usually lifted off the tender and loaded onto the yacht to ensure that an opportunistic thief does not disappear with the unattended tender and outboard motor. However, due to the weight of the motor, this is often a difficult and laborious task. On the other hand, this may be less tiring than physically rowing out to the mooring site in a rowing boat. Further, the upkeep and running costs for an outboard motor are relatively high considering that it is primarily being used merely to propel the tender to the moored vessel, not to mention the cost of purchasing an outboard motor for this purpose initially.

OBJECT OF THE INVENTION The object of the present invention is to disclose a portable, lightweight marine propulsion device that is known to be cheaper to buy than a typical outboard motor and is approx 8 kg assembled., half the weight of a small outboard motor, offering the user a second use for an existing motor.

From cutting grass to propelling small watercraft in less than 2 minutes, then back again when required.

SUMMARY OF THE INVENTION The object is preferably achieved with a pre-existing brush cutter/whipper snipper, then the owner is able to purchase a marine propulsion device at low cost, and by replacing existing grass cutting adaptor with a propulsion device, it can then be used as a propulsion unit for small watercraft In this way, the main component of the brush cutter containing the said engine and inner drive shaft and outer shaft to which die marine propulsion device is adapted, then offers dual purpose in that either the abovementioned marine propulsion device or a conventional grass or vegetation cutting adaptor can be connected.

Furthermore, the use of this marine propulsion device is not limited to the propulsion of boats and has equal application in the propulsion of any small watercraft. Traditionally, craft within this category have relied on a user paddling, the wind or the waves to propel them through the water. This can often be a laborious and time consuming method of propulsion.

In accordance with the first aspect of the present invention there is disclosed a marine propulsion device that can be quickly changed onto whipper snippers or brush cutters comprising an engine and a first shaft rotatably mounted within outer shaft and rotatable by said engine, said marine propulsion device comprising a propeller connected to a second shaft, a protective housing for said propeller and supporting said second shaft, that has an internal thread to couple said drive shafts by die use of brass drive inserts. Fig 5-17 and the new drawing Fig 7 shows that there are seven brass inserts in each propulsion unit kit comprising, two squares 6-Smm two flats 6-Smm and three different spline arrangements 8mm 9spline 7mm 7spline 6mm lOspline. The drive inserts are threaded on the OD for accessing the said second shaft /propeller shaft, allowing the propulsion unit to be compatible and easily fitted to the users whipper snipper or /brush cutter unit allowing their simultaneous rotation by said engine. 3 DESCRIPTION OF THE FIGURES Three embodiments of the present invention will now be described with reference to the drawings in which: • Fig. 1 is a perspective view of a prior art brush cutter with the brush cutting attachment disconnected from the engine-driven shaft.

• Fig. 2 is a perspective view of a first embodiment of the marine propulsion device • Fig. 3 is a side perspective view of the device of Fig. 2 • Fig. 4 is an aid of view of the device • Fig. 5 is a cross-sectional view of die device taken along the line V-V of Fig. 4 • Fig. 6 is a side view of a canoe embodiment in use • Fig 7 is a cross section view showing the said second shaft /propeller shaft and drive ends of whipper snippers and brush cutters and said brass drive inserts.

DETAILED DESCRIPTION Turning now to Fig. 1, it is evident that the prior art brush cutter 1 takes the form of a drive shaft 2 housed within outer shaft 3 and connected such that the shaft 2 is rotatable by an engine 4. The engine drives the rotation of the drive shaft 2 via a centrifugal clutch (conventional — but not illustrated.) A brush cutting device 5 can be connected to, and disconnected from, the free end 6 of the drive shaft 2 by using the drive inserts described in Fig 5-17 Fig 7.-8 A first form of a marine propulsion device 7 is illustrated in Figs. 2-5. The device 7 takes the form of a twin or three blade low pitch propeller 10 fixed to a propeller shaft 8. The shaft 8 is rotatably mounted in an aid bearing of water lubricated bushes being of Teflon or ceramic materials supported by a three-armed spider 11. A longitudinal cylindrical housing 12 support the spider 11 and protects persons from injury by coming into contact with the tips of die blades 13 of the propeller 10. Additionally, the protective housing 12 and supporting struts 18 guards the blades 13 against damage from coming into contact with submerged objects while the propeller 10 is rotating. A sleeve 15 having a bearing or water lubricated bushes of teflon or ceramics 16 for the shaft 2, is retained in the free end of the outer shaft 3 by a quick release clip 14 in an interference fit. The drive shaft 2 is connected to the propeller shaft 8 by drive inserts of different shapes and sizes 17 and illustrated in fig 7 As die said engine 4 drives the rotation of the shaft 2 which is in turn connected to the said propeller shaft 8, the propeller 10 fitted rotates simultaneously with said drive shaft 2.

A second embodiment of a canoe 20 is illustrated in Fig. 6 where die assembled unit is demonstrated in one of its many uses on small watercraft. Offering user safety and a lightweight propulsion device. 1 9 JAN 2007 receives.

Fig 7 Is a cross section view showing the different drive ends of a whipper snipper/ brush cutter and showing the internal threaded end of said second shaft/ the propeller shaft for receiving the selected brass drive insert Fig 7 -1 shows existing drive end of whipper snipper/ brush cutters 2 shows the different shapes and sizes of drive ends 3 shows outer housing tube that supports the spacers and propeller bush or bearings and supporting struts 4 shows propeller shaft with female thread for receiving the selected male threaded drive insert 5 shows the cross section of a three bladed propeller that has been made with low pitch to suit the high revs produced by these small motors 6 shows one of three nylon spacers used to fit different sized outer shafts 7 shows a nylon bush or a bearing assembly 8 shows the side elevation of a brass drive insert with a threaded O.D to allow fitting into female threaded prop shaft or second shaft all the inserts are the same size except they have different internal shapes and sizes 9 shows the end elevation of brass drive inserts showing the different shapes and sizes of internal drive shapes allowing the user to select the one insert that suits their whipper snipper or brush cutter and then the one selected insert can be screwed into the said propeller shaft allowing it to be used as a propulsion unit. intellectual property office of n.2. 1 9 JAN 2007 RECEIVED

Claims

CLAIM: 1 A marine propulsion device that will adapt onto whipper snippers or/brush cutters having m engine aid a first shaft rotatably mounted within outer shaft and rotatable by said engine, connected througjh a centrifugal dutch said marine propulsion device comprising of: • A two or three Uaded propeller having been designed with low pitched blades that are compatable with die higji revs produced by these small motors aid connected to a second shaft and • A protective housing fix* said propeller and to support said second shaft; and said brass cfrive inserts Fig 7-8 have been developed to aHow interconnection between first and second shaft and will permit simultaneous rotation by said engine allowing it to be used as a quick release propulsion unit suitable to propel small watercraft Offering die user a voy safe second use of an existing whipper snipper/brush cutter power source. END OF CLAIMS INTELLECTUAL PROPERTY OFFICE OF N2. - 5 MAR 2007 RECEIVED