Water craft driven by human-powered land vehicle

Technical field

The present invention relates generally to water craft supporting and driven by human-powered land vehicles, such as bicycles.

Background of the Invention

International Patent Publication WO 96/15026 describes a collapsible water craft comprising two floats joined by a structure to which a bicycle may be clamped and which enables the user to operate the craft in like manner to the way the bicycle is operated on land. A propeller assembly is connected to the front wheel and to a pivoting joint defining a generally vertical steering axis, allowing the propeller to be steered by the bicycle's handlebars. The propeller is driven, through a flexible shaft, by a roller pressed to contact the rear tyre.

While the sealed propellor assembly itself is a compact unit, the additional pivoting joint supporting the assembly for steering adds significant bulk, increasing the space required when storing or transporting the craft in its collapsed state. Furthermore, there is a need to provide a hinge mounting for the propellor assembly such that, with the craft assembled ready for launching, the propellor can be swung up clear of the base of the floats to prevent it being damaged by contact with the ground. It would be advantageous if such a hinge would also allow the propellor to retract when driven into an obstruction.

It is an object of the present invention to address the above needs, or more generally to provide an improved watercraft.

Disclosure of the Invention

According to one aspect of the present invention there is provided a water craft driven by a human-powered land vehicle having a crank rotated to drive the land vehicle, the craft comprising:

• at least one float;
• supports for releasably securing the human powered vehicle to each float;
• a drive unit having:

  • a primary shaft mounted for rotation about a primary axis;
  • a housing;
  • a secondary shaft drivingly connected by a first gear set to the primary shaft, the secondary shaft being received in the housing and mounted for rotation about a secondary axis, and
  • a rotor drivingly connected to the secondary shaft to thrust water; whereby the housing is pivoted about the primary shaft axis for raising and lowering the rotor and about the secondary shaft axis for directing the thrust from the rotor;

• the craft further including transmission means for transmitting drive torque from the crank to the primary shaft, and
• steering means connected to the housing for transmitting a user's steering movement to pivoting of the housing about the secondary shaft axis.

The rotor may be mounted within the housing or externally of the housing. For instance, the rotor may be mounted on the secondary shaft within the housing.

Alternatively, the drive unit further includes:

• a propeller shaft supported in bearings in the housing for rotation about a propeller shaft axis;
• a second gear set drivingly connecting the secondary shaft to the propellor shaft, and
• wherein the rotor is mounted on the propellor shaft externally of the housing.

Preferably the land vehicle includes steering apparatus for steering a wheel of the land vehicle and the steering means transmits steering movement from the steering apparatus to the housing. Alternatively, the steering means may comprise a handle fastened to the housing so as to allow the user to pivot the housing about the secondary axis.

Preferably the at least one float is elongate, the primary shaft extends transversely relative to the float, and the secondary shaft extends substantially perpendicular to the primary shaft.

Each gear set preferably includes a meshed pair of bevel gears.

Preferably the transmission means includes a toothed sprocket fixed to the primary shaft and connected by an endless member to a chainwheel fixed to the crank. The endless member may a chain or a toothed belt.

The drive unit preferably further includes a mounting bracket fixed to the upper housing for releasably connecting the drive unit to the land vehicle, the mounting bracket having a tongue adapted to be received in a channel formed in a fitting fixed to the land vehicle, the channel extending substantially parallel to the axis of the crank for allowing the fixed position of the drive unit to be varied in the direction of the channel axis.

According to another aspect of the present invention there is provided a collapsible water craft driven by a human-powered land vehicle having a crank for driving the land vehicle and steering apparatus for steering a wheel of the land vehicle, the craft comprising:

• at least one float;
• supports for releasably securing the human powered vehicle to each float;
• a drive unit having:

  • a primary shaft mounted for rotation about a primary axis;
  • a housing;
  • a secondary shaft drivingly connected by a first gear set to the primary shaft, the secondary shaft being received in the housing and mounted for rotation about a secondary axis, and
  • a rotor drivingly connected to the secondary shaft to thrust water; whereby the housing is pivoted about the primary shaft axis for raising and lowering the rotor and about the secondary shaft axis for directing the thrust from the rotor;

• the craft further including a toothed sprocket fixed to the primary shaft and connected by an endless member to a chainwheel fixed to the crank
• for transmitting drive torque from the crank to the primary shaft, and
• steering means connected to the housing for transmitting steering movement from the steering apparatus to the housing.

This invention provides a water craft which is effective and efficient in operational use, and which by its modular construction allows a human-powered land vehicle to be readily adapted for use on water. The water craft may be economically constructed and collapses to a compact unit, particularly providing a compact drive unit providing both steering and hinging for the thrust assembly.

Brief Description of the Drawings

Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings, wherein:

• Figure 1 is a side elevation of a preferred embodiment of the water craft of the invention (showing a bicycle fixed in position);
• Figure 2 is a pictorial view of the water craft of Fig. 1;
• Figure 2a is an enlarged view of the connection of the inner ends of the steering cables to the drive unit;
• Figure 2b is an enlarged view of the connection of the outer ends of the steering cables to the forks of the bicycle;
• Figure 2c is an enlarged view of the connection of the outer ends of the cross members to the floats;
• Figure 3 is an end view of the drive unit of the water craft of Fig. 1;
• Figure 4 is a section along line AA of Fig. 3;
• Figure 4a is an enlargement of detail C of Fig. 4;
• Figure 5 is a side view of the drive unit of Fig. 3;
• Figure 6 is a section along line BB of Fig. 5;
• Figure 7 is a top view of the drive unit of Fig. 3;
• Figure 8 is a side view of the drive unit of Fig. 3;
• Figure 9 is a pictorial view of an alternative thrust assembly for the drive unit of Fig. 3, and
• Figure 10 is a sectioned pictorial view of the thrust assembly of Fig. 9.

Description of the Preferred Embodiments

Referring to Fig. 1 of the drawings, the water craft 1 of the invention, in the preferred embodiment illustrated, generally includes a pair of floats 2a, 2b (float 2a shown partially cut away for clarity) connected by supports 3 for a bicycle 4, or another human-powered land vehicle. A drive unit 5 mounted to the bicycle 4 propels the water craft 1, thrust being transmitted from the user's rotation of the pedal-operated crank 6 and steering from turning of the handlebars 7.

As shown in Fig. 2, the water craft 1 is collapsible for storage or transport, the floats 2 each being formed from an inflatable skin having tapered bow and stern portions 8, 9 joined by a generally tubular portion 10 to form a pocket which defines the shape of each hull when inflated.

The floats 2 are joined by the supports 3, which include front and rear cross-members 11, 16 having connectors 12 at each end for releasable connection to connectors 13 provided on the floats 2a, 2b. An upright 14 is detachably fixed by joint 52a at one end to the centre of the cross member 11 and engages a mount 15a at the opposing end, the mount 15a being fixed, as by welding, to the frame of the bicycle 4 and secured to the upright 14 by a fastener 80. In a like manner, a pair of uprights 17a, 17b are fixed at their lower ends by respective joints 52b, 52c near the centre of the cross member 16, each of their upper ends engaging a mount 15b, 15c fixed to a respective chain stay 21 of the bicycle frame adjacent the rear axle.

Referring to Figs 2-6, a two-part connector includes a first part 20a and second part 20b. The first part 20a is in the form of a bracket fixed to the chain stays 21 (for instance, permanently fixed by fasteners or welding) for releasably securing the drive unit 5. Mounting the first connector 20a to the chain stays 21 allows the drive unit 5 to positioned between the crank 6 and rear wheel, however it will be understood that with appropriate modification, such as extending the chain stays 21 rearwardly, the first connector 20a may be fixed to the frame of the bicycle behind the rear wheel. The first connector 20a has a transversely aligned channel 22 in which a tongue 23 on the second connector 20b is received. The tongue 23 has opposing shoulders 53 on either side which generally abut lips 54 on either side of the channel 22, to support the tongue 23 vertically while allowing its transverse position to be adjusted. A fastener 24 extends (in the longitudinal direction of the watercraft 1) through aligned apertures in the first and second connectors 20a, 20b to connect the drive unit 5 to the bicycle.

A thrust assembly 55 includes a propellor shaft 30 mounting a helical three-bladed rotor 31. A sprocket 25 mounted on the primary shaft 26, connected by a first pair of bevel gears 27a, 27b to the secondary shaft 28. A second pair of bevel gears includes gear 29a fixed to the secondary shaft 28 and meshed with bevel gear 29b fixed to the propellor shaft 30. The end of the propellor shaft 30 projecting from the housing 19 has the rotor 31 mounted to it.

In Fig. 2, the drive unit 5 and the attached second part 20b, are shown separated from the first part 20a in the transverse direction 60. The drive unit 5 further includes an idler wheel 61 mounted on a bracket 62 connected to the tongue 23. The chain 63 engages the sprocket 25, crank-driven chainwheel 65 and the idler wheel 61. The idler wheel 61 engages the loose side of the chain 63 to increase the angular engagement between the chain 63 and the sprocket 25.

The housing 19 has a tubular upper portion 19a and a lower portion 19b sealingly enclosing the lower end of the secondary shaft 28 and the propellor shaft 30. The propellor shaft 30 is supported by bearings 32a, 32b in lower portion 19b for rotation about the propellor shaft axis 33.

The primary shaft 26 is supported by bearings 36a, 36b in a mount 38 for rotation about the primary shaft axis 39. Mounted on either transverse side of the mount 38, concentrically with primary shaft axis 39, are bearings 40a, 40b received in respective flanges 41 a, 41 b fixed to the tongue 23 upon which the mount 38 and connected housing 19 are pivoted for moving the rotor 31 between the lowered position shown and a raised position (see Fig. 8).

Formed on the second connector 20b, projecting inwardly between the flanges 40a, 40b is an abutment 57. As best seen in Fig. 4a, a projection 38 extends radially outward of the mount 38, a threaded aperture in the projection 60 receives a threaded fastener 56 the end of which projects to contact the abutment 57 to limit the angular tilting of the mount 38 and rotor 31. The length adjustment achieved through rotation of the stop fastener 56 provides a trim adjustment for the drive unit. The thrust from the rotor 31 during forward movement produces a torque transmitted by the stop fastener 56 engaging the abutment 57.

The secondary shaft 28 is mounted for rotation about the secondary shaft axis 35, the lower end held in bearing 34a in the housing 19 and the upper end being held in bearing 34b in the mount 38. A journal 42 connects the mount 38 and housing 19a, allowing relative rotation therebetween for directing the thrust from the rotor 31.

As shown in Fig. 7, the propellor shaft axis 33 can be pivoted about the secondary shaft axis 35 for steering the water craft, between the position shown for forward travel, to the rotated positions 33', 33". Fig. 8 shows the rotor 31 rearwardly inclined, and raised relative to the upright position shown in dashed outline, the housing 19 having been pivoted about the primary shaft axis 39, for instance when the water craft 1 rests upon the ground, of if the drive unit 5 strikes an obstruction.

The freewheeling hub 43 of the rear wheel of the bicycle is driven in the conventional manner by chain drive from the crank 6. While many bicycles may have multiple chainwheels coaxial with the crank 6, in the embodiment illustrated only a single chainwheel 65 is provided on the crank, requiring the chain driving the freewheeling hub 43 to be removed when it is required to drive the drive unit 5.

A cable assembly includes a pair of sheathed cables 46, 47, each comprising a sheath 67 holding a cable 68. One end of each of the sheathed cables 46, 47 is fixed to the drive unit 5, the sheaths 67 abutting respective tubular fixtures 48 through which the cables 68 extend, before passing around respective rollers 70. The respective ends of the cables 68 are held in clamps 71 fixed to the housing portion 19a. The rollers 70 themselves are fixed to the mount 38, being arranged symmetrically either side of a central longitudinal plane of the drive unit 5 to direct the cable from generally radial alignment to longitudinal alignment with respect to the tubular housing portion 19a. The opposing ends of the cables 46, 47 are releasably connected to the bicycle 4, the sheaths 67 abutting respective fixtures 501 on the frames, while loops 66 in the ends of the cables 46, 47 are passed over nubs 51 fixed to the steering forks 49 on either side of the steering axis 167.

An alternative thrust assembly 55' is illustrated in Figs 9 and 10, wherein the rotor 31' includes eight substantially radially-aligned blades 51 and is mounted to the lower end of the secondary shaft 28 enclosed within a toroidal portion 50 of the housing 19'. A circular inlet aperture 52 is provided in the base of the toroidal portion 50 aligned with the secondary shaft axis 35 and a radially extending nozzle 53 is provided for directing a jet of water from the assembly.

In its collapsed state (not shown) the water craft 1 can be stored or carried readily upon the bicycle, ready for use, together with a pump and tools required for assembly. After inflating the floats 2, they are joined together by the front and rear cross-members 11, 16 to which uprights 14 and pair of uprights 17a, 17b are fixed, before clamping the bicycle in place. The drive unit 5 is fixed in place by entering the tongue 23 into the channel 22 and securing the fastener 24 before the transmission chain is connected to the sprocket 25. To connect the steering cable assembly the sheaths 67 are attached to abut the respective fixtures 501 and the loops 66 in the ends of each of the cables 46, 47 are passed over the respective nubs 51.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof.