U.S. patent application number 12/045598 was filed with the patent office on 2008-12-04 for amphibious vehicle transmission.
This patent application is currently assigned to GIBBS TECHNOLOGIES LTD.. Invention is credited to Stephen John Briggs, Simon James Longdill, Hans Weekers.
Application Number | 20080299844 12/045598 |
Document ID | / |
Family ID | 33485048 |
Filed Date | 2008-12-04 |
United States Patent
Application |
20080299844 |
Kind Code |
A1 |
Longdill; Simon James ; et
al. |
December 4, 2008 |
AMPHIBIOUS VEHICLE TRANSMISSION
Abstract
An amphibious vehicle has retractable road wheels to allow
planing over water. Power to the road wheels is disconnected
automatically as the wheels are retracted. This may be achieved
through a cable attached to a suspension rocker arm to disconnect a
dog clutch attached to the input shaft of a differential as the
wheels are retracted; and vice versa. The system may be fitted to a
steered axle or to any suitable retractable suspension system.
Inventors: |
Longdill; Simon James; (Mt.
Wellington, NZ) ; Weekers; Hans; (Mt. Wellington,
NZ) ; Briggs; Stephen John; (Mt. Wellington,
NZ) |
Correspondence
Address: |
FULWIDER PATTON LLP
HOWARD HUGHES CENTER, 6060 CENTER DRIVE, TENTH FLOOR
LOS ANGELES
CA
90045
US
|
Assignee: |
GIBBS TECHNOLOGIES LTD.
Warwickshire
GB
|
Family ID: |
33485048 |
Appl. No.: |
12/045598 |
Filed: |
March 10, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11255776 |
Oct 21, 2005 |
7410396 |
|
|
12045598 |
|
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Current U.S.
Class: |
440/12.52 ;
440/12.56; 440/12.57 |
Current CPC
Class: |
B60F 2301/04 20130101;
B60F 3/0007 20130101 |
Class at
Publication: |
440/12.52 ;
440/12.57; 440/12.56 |
International
Class: |
B60F 3/00 20060101
B60F003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 22, 2004 |
GB |
GB 0423517.2 |
Claims
1. An amphibious vehicle having a planing surface, comprising: a
prime mover; land propulsion means; marine propulsion means;
transmission means for transmitting power generated by the prime
mover to the land and/or marine propulsion means; and retractable
suspension means capable of retracting and protracting the land
propulsion means, wherein the land propulsion means is
automatically decoupled by the transmission means when retracted by
the retractable suspension means and wherein the land propulsion
means is retracted to a position above said planing surface.
2. An amphibious vehicle as claimed in claim 1, wherein the land
propulsion means is automatically coupled by the transmission means
when protracted by the retractable suspension means.
3. An amphibious vehicle as claimed in claim 2, wherein the
transmission means is mechanically connected to the retractable
suspension means and the automatic coupling and decoupling of the
land propulsion means is effected by physical movement of the
retractable suspension means.
4. (canceled)
5. An amphibious vehicle as claimed in claim 3, wherein the
mechanical connection between the transmission means and the
retractable suspension means is a mechanical linkage.
6. An amphibious vehicle as claimed in claim 1, wherein the
transmission means comprises a dog clutch to effect coupling and
decoupling of the land propulsion means.
7. (canceled)
8. (canceled)
9. An amphibious vehicle as claimed in claim 1, wherein the prime
mover is an internal combustion engine.
10. An amphibious vehicle as claimed in claim 1, wherein the land
propulsion means comprises road wheels.
11. An amphibious vehicle as claimed in claim 1, wherein the land
propulsion means comprises tracks.
12. An amphibious vehicle as claimed in claim 1, wherein the marine
propulsion means comprises a jet drive.
13. An amphibious vehicle as claimed in claim 1, wherein the marine
propulsion means comprises a screw propeller.
14. An amphibious vehicle as claimed in claim 1, wherein the
transmission means comprises a transfer case.
15. An amphibious vehicle as claimed in claim 1, wherein the
transmission means comprises a continuously variable
transmission.
16. An amphibious vehicle as claimed in claim 1, wherein the
transmission means comprises a differential.
17. An amphibious vehicle as claimed in claim 1, which is capable
of planing when operating in marine mode.
18. An amphibious vehicle as claimed in claim 1, wherein the land
propulsion means is retractable above the static water line.
19. An amphibious vehicle having a planing surface, comprising: a
prime mover; land propulsion means; marine propulsion means; a
transmission for transmitting power generated from the prime mover
to the land and/or marine propulsion means; and a retractable
suspension capable of retracting and protracting the land
propulsion means, wherein the land propulsion means is retractable
to a position above said planing surface and protractable to a
position outboard of said planing surface, wherein: the land
propulsion means is automatically decoupled from the transmission
when retracted by the retractable suspension; the land propulsion
means is automatically coupled to the transmission when protracted
by the retractable suspension; and the transmission is connected to
the retractable suspension and the automatic coupling and
decoupling of the land propulsion means is effected by physical
movement of the retractable suspension.
20. (canceled)
21. An amphibious vehicle as claimed in claim 19, wherein the
connection between the transmission and the retractable suspension
comprises a mechanical linkage.
22. An amphibious vehicle as claimed in claim 19, wherein the
transmission comprises a dog clutch to effect coupling and
decoupling of the land propulsion means.
23. (canceled)
24. (canceled)
25. (canceled)
26. (canceled)
27. (canceled)
28. (canceled)
29. An amphibious vehicle, comprising: a prime mover; land
propulsion means; marine propulsion means; transmission means for
transmitting power generated by the prime mover to the land and/or
marine propulsion means; and retractable suspension means capable
of retracting and protracting the land propulsion means, wherein
the land propulsion means is automatically decoupled when retracted
by means of a return spring.
30. An amphibious vehicle, comprising: a prime mover; land
propulsion means; marine propulsion means; transmission means for
transmitting power generated by the prime mover to the land and/or
marine propulsion means; and retractable suspension means capable
of retracting and protracting the land propulsion means, wherein
the land propulsion means is automatically decoupled by the
transmission means when retracted by the retractable suspension
means wherein the transmission and the retractable suspension are
interlinked by a push-pull cable.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims priority from Great Britain
Application Serial No. 0423517.2, filed Oct. 22, 2004.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to transmission arrangements
for amphibious vehicles, and in particular to control aspects
thereof.
[0003] It is known for amphibious vehicles to have road wheels
which can be retracted above the water line for use of the vehicle
on water. This has the advantage of reducing hydrodynamic drag;
particularly where the vehicle is designed to plane over the
surface of the water, as such vehicles travel faster than
displacement vehicles.
[0004] Where such wheel retraction systems are fitted, and the road
drive and marine drive are driven in parallel, for example as
disclosed in the applicant's co-pending application published as WO
02/07999, it is preferable to disconnect road drive on water. An
example of road drive disconnection is disclosed in WO 02/14092,
also of the present applicant. In this disclosure, a decoupler is
provided in each wheel driveshaft. Such decouplers have many
virtues, but light weight and simplicity are not among them.
SUMMARY OF THE INVENTION
[0005] It is advantageous if a single decoupler can be arranged to
decouple drive to both wheels. This could be achieved by situating
the single decoupler, for example, on the input driveshaft of the
differential, where a single driven axle is provided. However, the
location of the decoupler is not a solution to the problem of
excess weight and complexity; the decoupler still needs to be
activated.
[0006] Since there are a number of adjustments to be made to an
amphibious vehicle during mode change on entry into or egress from
water, it is preferable to reduce as far as possible the number of
tasks that have to be effected directly by the driver. This helps
simplify control of the vehicle at a critical time, one which is
not necessarily intuitive to the novice amphibian driver.
Accordingly, the present invention provides for automatic
decoupling of road drive when the wheels are retracted during mode
change from land mode to marine mode and for automatic coupling of
road drive when the wheels are protracted during mode change from
marine mode to land mode.
[0007] In a first aspect, the present invention provides an
amphibious vehicle comprising: [0008] a prime mover; [0009] land
propulsion means; [0010] marine propulsion means; [0011]
transmission means for transmitting power generated by the prime
mover to the land and/or marine propulsion means; and [0012]
retractable suspension means capable of retracting and protracting
the land propulsion means, wherein: [0013] the land propulsion
means is automatically decoupled by the transmission means when
retracted by the retractable suspension means.
[0014] In a further aspect the amphibious vehicle comprises a body;
a power train comprising a prime mover, a road transmission, and a
marine transmission; and a suspension capable of retracting road
wheels; where the road transmission is decoupled automatically as
the road wheels are retracted.
[0015] The road wheels may drive at least one tracked drive.
[0016] The road transmission may be decoupled at a differential
input.
[0017] The decoupling means may be a dog clutch.
[0018] The decoupling means may be mechanically linked to the
retractable suspension; particularly by a push-pull cable.
[0019] A spring return means may be fitted to the actuator for the
decoupling means.
[0020] These and other features and advantages of the present
invention will become apparent from the following detailed
description of preferred embodiments which, taken in conjunction
with the accompanying drawings, illustrate by way of example the
principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a schematic side elevation view of an amphibious
vehicle according to the present invention;
[0022] FIG. 2 is a perspective view from above and to one side of
the vehicle of FIG. 1 with the upper body and hull removed;
[0023] FIG. 3 is a schematic side elevation view of a power train
arrangement of the vehicle of FIG. 1;
[0024] FIG. 4a is a plan view from above of a retractable
suspension system for an axle of the vehicle of FIG. 1, with the
wheel assemblies protracted;
[0025] FIG. 4b is a detail view of the apparatus for effecting
coupling and drive to the protracted wheel assemblies of FIG.
4a;
[0026] FIG. 5a is a plan view from above of a retractable
suspension system for an axle of the vehicle of FIG. 1, with the
wheel assemblies retracted;
[0027] FIG. 5b is a detail view of the apparatus for effecting
decoupling of drive from the retracted wheel assemblies of FIG. 5a;
and
[0028] FIG. 6 is a transverse elevation view along plane VI-VI in
FIG. 1, of a rear axle of the vehicle of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] As can be seen from FIG. 1, amphibious vehicle 2 has a prime
mover 4 driving a jet drive 6 through a marine transmission,
described below with reference to FIG. 2. Road traction is provided
by wheels 8, which are driven through a road transmission. The
wheels 8 are shielded by wheel arches 12. The vehicle body
comprises an upper body 14 and a hull 16, which are formed
separately and joined at split line 18. A chassis is also provided,
as is described in further detail below. If this chassis is bonded
to or otherwise attached to or integrated with the bodywork, it may
be regarded as part of the overall body structure. The hull 16 has
a planing surface 20. A driver's seat 22 is provided with one or
more passenger seats 24 situated astern of the driver's seat 22.
The seating axis is coincident with the longitudinal axis of the
vehicle 2, or parallel thereto. The axis of the prime mover 4 is
also coincident with, or parallel to, the longitudinal axis of the
vehicle 2. Driver controls are provided, in this preferred
embodiment by virtue of handlebars 28. A windscreen 26 is provided
for weather and spray protection.
[0030] FIG. 2 illustrates a perspective view of the vehicle rolling
chassis 60 in isolation. A front, steered, axle 40 can be seen to
the right; and a rear, powered, non-steered axle 50 to the left.
The prime mover 4 may also be seen, mounted longitudinally, and
substantially centrally in the vehicle. Numeral 70 denotes a
support frame, which will be further described later.
[0031] FIG. 3 is a schematic representation of essential integers
of the power train of the vehicle of FIG. 1. Prime mover 4 has a
crankshaft 38, coupled fixedly to a first driveshaft 40. Driveshaft
40 is in turn connected to and provides drive to a transfer case
30. Marine driveshaft 5 is also connected to and is driven by the
transfer case 30, to provide power to marine drive means 6, which
preferably takes the form of a jet drive. The transfer case 30 may
incorporate a decoupler or a fixed ratio change for the marine
drive 6. A reverse gear may also be provided here for the marine
drive 6, to allow for manoeuvring, or for clearance of weed or
other debris, etc., from inside the jet drive.
[0032] Transfer case 30 also provides a road transmission output
along vertical output shaft 86. Bevel gears are used to transfer
power from shaft 40 to shaft 86. The change speed transmission 32
is shown as a CVT (continuously variable transmission), comprising
input pulley assembly 90, output pulley assembly 92, and a drive
belt 91 connecting the two. The output from CVT 32 is taken down to
differential 34 by vertical output shaft 88. The input to
differential 34 is provided through a dog clutch 33. Numeral 99
denotes an electric motor, preferably a starter motor with attached
Bendix drive. Such a drive may be used to provide a reverse gear
where transfer case 30 does not provide such a facility.
[0033] FIGS. 4a, 4b, 5a, and 5b illustrate the retractable
suspension assembly of one axle of the vehicle of FIG. 1 in
isolation, to more clearly show how the present invention works.
Retraction device 242, preferably a hydraulic cylinder 244
including a rod 246, is pivotally connected to the vehicle chassis
(not shown) at mounting point 250. This mounting point may be on a
support frame, such as item 70 in FIG. 2. The distal end of rod 246
is fixed to a pivot 248, to which there is also fixed a rocker arm
232, with a central pivot 240. Each end of rocker arm 232 has a
pivot 234, to which is connected a wheel suspension assembly 224,
comprising a coil spring 226 and a telescopic damper 228 with a
push rod 230. A push-pull cable assembly 310, comprising an outer
cable 316 and an inner cable 312, is fixed to the vehicle chassis
at mounting 318; and to the rocker arm 232 at mounting point 314.
The distal end of each suspension assembly 224 is pivotably linked
to a link arm 220. These link arms 220 are in turn linked to
respective torsion tubes 216, 218. The link arms 220 and torsion
tubes 216, 218 are mounted longitudinally in the vehicle 2; similar
members 216', 218' can be seen from another perspective in FIG.
7.
[0034] For a driven axle, as shown, torsion tubes 216, 218 are
fixed to lower suspension arms 214 which enclose driveshafts (not
shown). Upper suspension members 215 are also provided, mounted to
be swingable about inner pivots 213. Wheel hubs 204 are mounted to
the distal ends of lower suspension arms 214.
[0035] As can be seen in FIG. 5a, when ram 244 is retracted, its
rod 246 is retracted into the cylinder of ram 244. Rocker arm 232
is therefore rotated (clockwise, as shown) about pivot 240. This
pulls suspension assemblies 224 in towards the centre of the
vehicle 2, rotating link arms 220 and torsion tubes 216 and 218.
This in turn pulls lower suspension arms 214 upwards. Wheel hubs
204 are thus also rotated upwards, raising the road wheels (not
shown) clear of the surface of the water, even when the vehicle 2
is banked in turns when the vehicle 2 is operated over water. It
can also be seen from FIG. 5a, that the geometry of this system is
such that upper suspension members 215 fold up beyond a vertical
position, so that their inboard ends are now inboard of pivots
213.
[0036] As this wheel assembly retraction process takes place, it
can be seen through comparison of FIGS. 4a, 4b and 5a, 5b that
inner cable 312 is pulled through the outer cable 316 (which is
fixed in position at mounting 318). As can best be seen from FIG.
5b, this in turn allows cable assembly 310 to disengage dog clutch
33 (located above differential 34), thus achieving the object of
automatically disconnecting road drive to wheels 8 as said wheel
assemblies are retracted by the retractable suspension. The reverse
process will of course also apply, so that road drive is
automatically reconnected as said wheel assemblies are protracted,
from the FIGS. 5a, 5b situation to that shown in FIGS. 4a, 4b. A
spring 320 (shown in FIGS. 4b, 5b) may be fitted to cable assembly
310 as a safeguard, to ensure a failsafe condition (if the cable
snaps) in which the clutch 33 is closed. Also the spring 320 acts
to keep the cable 312 in tension; the clutch 33 is opened against a
biasing force applied by the spring 320. The spring stores energy
which is subsequently used to shut the clutch 33 when the movement
of rotor 232 allows the cable to slide to permit rotation of arm
325.
[0037] The term "dog clutch" is often used in the art to describe a
sprag engaging on a ratchet type wheel. Such a clutch has the known
weakness of only being able to transmit power in a single
rotational direction; any attempt to transmit power in the reverse
direction will simply snap the sprag clutch arm. As can be seen
from FIGS. 4b and 5b, however, the dog clutch 33 used in the
present invention has two gear wheels 330, 331 each provided with
teeth 332 of substantially square profile; and can therefore
transmit power equally well in both directions. Furthermore, the
bevel gear 335 shown engaging and disengaging with the dog clutch
33 must be free to rotate on the horizontal shaft 336. Were it to
be keyed to shaft 336, drive to the road wheels would be
permanently engaged. On the other hand, the dog clutch sliding gear
330 must be splined to the shaft 336. As can be seen from FIG. 4b,
an arm 325 is used to relay the motion of the dog clutch end of
cable assembly 310.
[0038] FIG. 6 shows a view from in front of the rear axle of the
vehicle of FIG. 1, to illustrate the spatial relationship of cable
assembly 310, dog clutch 33, and differential 34.
[0039] It will be appreciated that further modifications to the
transmission layout described above may be made as required without
departing from the scope of the invention. For example, other
suspension retraction mechanisms may pull the push-pull cable
equally well (e.g. directly acting hydraulic or pneumatic
cylinder(s), electric motor(s) or linkage mechanism(s). A dog
clutch could be applied to one or both differential output shafts,
rather than to the input shaft; the entire arrangement could also
be applied to an axle which is both powered and steered.
Furthermore, rather than the lower suspension members being
tubular, they may be solid, or may take the form of wishbones.
[0040] While a particular form of the present invention has been
illustrated and described, it will be apparent to those skilled in
the art that various modifications can be made without departing
from the spirit and the scope of the present invention.
Accordingly, it is not intended that the invention be limited
except by the appended claims.
* * * * *