Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
_
THIS INVENTION relates to a carry towing vehicle for
carry towing vehicles.
By carry towing is meant, the towlng of a vehicle
whereby the front or rear end is raised or carried and is then
towed by a towing vehicle. Towing vehicles known to the
applicant for towing motor cars, are large and expensive
vehicles. Such towing vehicles make use of a hoist or winch to
suspend the front or rear end of a vehicle being carry-towed.
This, more often than not, results in damage to the bumpers or
fenders of the towed vehicle.
The applicant is also aware of smaller carry-towing
trailers which, because of lack of adequate braking or other
features, are not safe for use in the towing of vehicles of the
size contemplated by the applicant.
A carry towing vehicle according to the invention is
hereinafter referred to as a 'trailer'. Further, the 'towing'
of the vehicle must be understood to include its 'carry
towing'.
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It is an object of this invention to provide a light
towing trailer which can be coupled to a liyht towing vehicle
and which nonetheless has brakes of sufficient capacity to
permit the towing of even large passenger cars or light trucks
with safety.
SUMMARY OF THE INVENTION
Accordingly, the invention provides a carry towing
trailer which includes:
a chassis having support means for supporting a vehicle to
be carry towed;
a coupler at a leading end of the chassis for coupling to
a towing vehicle for towing in a longitudinal direction;
a pair of trailer wheels rotatably mounted about a
transverse axis and supporting the chassis, the trailer wheels
being of such a size and so positioned that, in use, they can
run within the track width of and under a vehicle to be carry
towed; and
an automatic override brake connected to the coupler and
operable on the -trailer wheels.
Under 'track width of a vehicle' must be understood
the spacing between a pair of wheels of the vehicle; the said
pair of wheels being mounted in their normal positions on the
vehicle.
Each of the trailer wheels may have a wheel rim and a
brake drum and a mounting ring, and securing means for securing
.
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the wheel rim via the mounting ring to the brake drum. The
wheel rim may be detachable from the mounting ring. A wheel
rim may be in two co-operating rim parts mating along a plane
at right angles to the rotational axis of the wheel. If
desired, the diameter of a brake dxum may be the same as the
diameter of the tire inside the opening wi-thin the beading. The
brake drum may have a spigot formation fitting snugly into a
socket defined by the cylindrical inner surface of the wheel
rim.
The support means may be disposed ahead of the
rotational axis of the trailer wheels.
The pair of wheels may have axles on a pair of
arms pivotally mounted on the chassis about a transverse axis.
The invention may further include displacement means
operable to displace the arms with the trailer wheels about
their pivotal axis relative to the chassis, so as to permit
raising and lowering of the chassis relative to a surface
supporting the wheels. The displacement means may include a
hydraulic ram operatively connected be-tween the chassis and
the arms. The displacement means may Eurther include a
hydraulic pump operable to supply hydraulic fluid under
pressure for operating -the hydraulic ram.
The support means may include a pair of transversely
spaced cradles adapted to receive a pair of wheels of a vehicle
to be carry towed. The support means may further include
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clamping means for clampingly engaging a vehicle to be carry
towed and the said clamping means may include a pair of
transversely spaced clamps for elamping an axle or part of a
vehicle to be carry towed.
The support means may be mounted on a teleseopie
member forming part of the chassis and which is telescopically
extendable and retraetable sueh that during loading such
mounting of the support means is behind the rotational axis of
the -trailer wheels, and such that during towing, the mounting
means is ahead of such axis.
The support means may include a support beam which
may be pivotally mounted on the telescopie member, about an
upwardly direeted axis, the beam being disposable longitudi-
nally when the trailer is unloaded and transversely when
lOaded.
A trailer according to the invention may further
include retracting means for retracting the teleseopie member
from an extended position into a re-tracted position. The
retracting means may include a wineh, and a winch rope with a
hook engageable with the telescopic memker.
By way of development, -the invention may inelude a
further pair of wheels having axles on a second pair of arms
pivotally mounted on the chassis about a transverse axis
disposed forwardly of the pivotal axis of the arms of the first
pair of wheels; and connecting means interconnecting
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-the arms of the two pairs of wheels to ensure that they can
move in unison.
The override brake may include a hydraulic plunger
and cylinder assembly operatively connected via a hydraulic
line on the chassis and thence via flexible conduits to
hydraulic brake cylinders provided on the trailer wheels, the
cylinder being mounted on the chassis, and the coupler being
connected to the plunger, lost motion being provided between
the coupler and the chassis during towing. The override brake
may also include a displaceable stop positionable to prevent
operation of the brakes of the trailer by taking up the lost
motion between the coupler and the chassis and thereby
preventing displacement of the plunger relative to the cylinder
during towing.
Embodiments of carry towing trailers in accordance
with the invention are now described by way of example with
reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings,
Figure l shows diagrammatically in side elevation a carry
towing trailer according to the invention, in use;
Figure 2 shows an oblique rear view of the carry towing
trailer, with the chassis in the partially lowered ex-tended
position;
Figure 3 shows an oblique rear view of the trailer in the
raised position showing in dotted the wheels of a vehicle being
towed located in the towing position;
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Figure 4 shows an oblique rear view of the trailer in the
retracted unloaded towing condition;
Figure 5 shows diagrammatically in side elevation another
embodiment of a carry towing trailer according to the
invention, in use;
Figure 6 shows an oblique rear view of the trailer of
Figure 5 in the retracted unloaded towing condition;
Figure 7 shows diagrammatically a side view of the wheel
arrangement of the trailer of Figures 5 and 6;
Figure 8 shows a three-dimensional view of a clamp for
clamping a vehicle to a trailer according to the invention;
Figure 9 shows an hydraulic diagram of the override brake
of the trailer of Figure 5;
Figure 10 shows a schematic diagram of a frame having
signalling lights; and
Figure 11 shows an axial section through a wheel and brake
drum assembly.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to -the drawings, reference numeral 10
refers generally to one embodin1ent of a carry towing trailer
according to the invention, having a pair of closely spaced
wheels 12 adapted to run within the track width of a vehicle 16
being carry towed by the trailer. The track width of the
vehicle 16 is the spacing between the wheels 14. The trailer
also has a coupler 18 for coupling to a -towing vehicle 20. The
coupler 18 has an automatic override brake (described more
fully hereafter) operable on the wheels of the trailer 10.
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The trailer has a chassis in the form of a beam 22
extending longitudinally and having a jockey wheel 24 at its
leading end, the wheels 12 being provided at its trailing end.
The trailer 10 is provided with vehicle support means
generally indicated by reference numeral 26, including a
support beam 28 having a pair of transversely spaced wheel
cradles 30. The support beam is pivotally supported on the
chassis about the upwardly directed axis of a pin 32. The
support beam 28 is also pivotally mounted about a longitudinal
10 axis intersecting the axis of pin 32, and providing limited
pivotal movement on either side of the pin 32. The cradles 30
are provided with flanges 30.1 to support them evenly on the
ground.
The wheels 12 are shown to be connected to the
15 chassis 22 via arms 34 having stub axles 36 rotatably
supporting the wheels of the trailer. The arms 34 are
pivotally mounted on the chassis 22 about a transverse axis.
The trailer further includes displacement means
including a hydraulic ram 38 having an anchor point 40 on the
20 chassis, and pivotally connected to -the arms 34 at 42 whereby
the chassis 22 may be raised and lowered relative to the wheels
and their supporting surface by displacing the arms 34 with
the trailer wheels, about their pivotal axis relative to
the chassis 22. The hydraulic ram 38 is operable by a
25 hydraulic pump 43 having a handle 4301.
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A telescopic member 22.1 forms part of the chassis
22, and is telescopically extendable and retractable. The
telescopic member 22.1 pivotally supports the support beam 28
about the axis of pin 32. The telescopic member 22.1 can be
drawn into the chassis 22 by means of retracting means
comprising a winch 44 and a winch rope 44.1 having a hook 46.
The winch is operable by means of a handle and ratchet
combination 48 and 50.
The coupler 18 embodies an au-tomatic override brake
system 60. A removable stop 62 is provided to render the
automatic operation of the brake inoperative, when desired.
The system comprises a shank 61 connec-ted to a piston inside
a master cylinder 64 having a reservoir 66, and comprises a
hydraulic line 68 and flexible conduits 68.1 connected to brake
cylinders 70 of the wheels 12.
In use, the carry towing trailer 10 is backed up to
the front or rear of a vehicle 16 which is to be towed.
Thereupon the telescopic member 22.1 is extended, as shown in
E'igure 2 of -the drawings. The chassis 22 is then lowered
fully, ie beyond the position shown in Figure 2 of the
drawings. The vehicle support beam 28 is then pivotally swung
about the axis of pin 32 until the wheel cradles 30 are in
alignment with the wheels of the vehicle 16 to be towed.
Thereupon, the winch hook 46 is hooked onto the vehicle which
is to be towed, and the winch rope 44.1 is hauled in by the
operation of the winch 44 by means of the handle and ratchet
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mechanism 48 and 50, until the wheels 14 seat in the wheel
cradles 30. Thereupon, the hook 46 is detached, and it is
hooked onto the handle 22.11. The hydraulic ram is then
pumped up, thereby causing the arms 34 to pivot about their
pivotal axis thereby raising the chassis 22. Once the chassis
has been raised, the winch is operated and the telescopic
member 22.1, with the wheels of the vehicle to be towed,
nesting in the cradles 30, is hauled in by operating the winch
44. The telescopic member 22.1 rolls on the chassis rollers
22.2. The extent to which the telescopic member 22.1 is hauled
in, is such that the pivotal axis of the pin 32 lies ahead of
the rotational axis of the wheels 12 as shown in Figure 1 of
the drawings.
The telescopic member 22.1 is provided wi-th catches
for retaining it in its retrac-ted position. These catches are
not shown but are in the form of gravity or spring-~iassed
catchesl co-operating with mating formations in the chassis 22.
When the carry towing trailer is not being used for
carry towing vehicles, then the support beam 28 will be swung
about the axis of pin 32 so that it lies in a longitudinal
direction~ as shown in Figure 4 of the drawings. The wheel
support means will be locked in position by a screw-type
locking handle 72/ screwing the wheel support 30 against pads
74 on the chassis 22.
Referring to Figures 4 and 9, when the towing vehicle
20, in operation, slows down or brakes, the trailer 10 will
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override the vehicle 20. The shank 61 will move inwards
thereby taking up lost motion and exerting pressure in the
master cylinder 64 and causing the brakes 70 to be applied.
When the vehicle 20 pulls the shank 61, the pressure is
reduced and the brakes are released.
When the towed vehicle is to be lowered, the ram is
retracted thereby causing the arms 34 to pivot. The chassis
is thereby lowered and the towed vehicle can be removed.
A feature of this invention is that the hydraulic
ram is provided with a valve to retain the ram in the chassis
in the raised position. Failure of hydraulic pressure in the
ram during towing will result in slight lowering of the
chassis until the support beam 28 or cradles 30 engage the
wheels 12 thereby exerting a braking force on the wheels 12.
The driver of the towing vehicle will then immediately become
aware of some faul-t in the trailer.
The trailer 10 has a detachable frame 76 (see Figures
4, 6 and 10) comprising a number plate and signalling light
arrangement operable via a seven core cable 78 and plug 79
from a towing vehicle. This arrangement is used when the
trailer is being taken unloaded from one place to ano-ther with
the support beam 28 in its longitudinal position. The
arrangement is detachably mounted on one wheel cradle 30. When
the trailer is to be loaded then the frame 76 is removed and is
temporarily secured by tie-on straps 81 to the rear of the
towed vehicle. The cord has sufficient length to permit this
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to be done. The frame 76 has room for a number plate 83,
number plate light 85, and rear lights 86, stop lights 88, and
indicator lights 90.
Instead of or in addition to wheel cradles 30, the
telescopic member 22.l may be provided with a clamp 80 as shown
in Figure 8, at its end remote from the winch 44. If desired,
a pair of such clamps may be provided, spaced transversely.
Such clamps can be in the form of pipe vices, as shown in
Figure 8, adapted to receive an axle 82 of a vehicle to be
towed. Instead of the axle 82, some other part of the chassis
of the vehicle -to be towed may be received into the jaw 84 of
the clamp. When two such clarnps are provided at a transverse
spacing then lateral stability will be provided during towing.
The clamps 80 may be mounted to be -transversely
adjustable in posi-tion on the support beam 28 to provide
adjustability in their transverse spacing. This is to
accommoda-te vehicles having different types of cons-truction
for their suspensions.
On the other hand for some applications, the
transverse spacing between the clamps 80 need not be very great
and may still lie within the space between the wheels 12.
Accordingly, with such a construction it is not necessary to
have the support beam pivotall~ mounted on the telescopic
member 22.l. The support beam 28 with clamps 80 can then be
fast with the telescopic member 22.l.
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Referring to Figures 5, 6 and 7 of the drawings,
another embodiment of a carry towing trailer in accordance with
the invention is shown. Parts of this embodiment corresponding
to parts of the first embodiment hereinbefore described, are
indicated by corresponding numerals. The description relating
to the first embodiment as illustrated in Figures 1 to 4 is in
principle also applicable to the second embodiment as
illustrated in Figures 5, 6 and 7.
The embodiment of the trailer in accordance to the
invention as described in Figures 5, 6, and 7, has two pairs of
wheels 12.1 and 12.2. The two pairs of wheels are provided at
the trailing end of the trailer adapted to run within the track
width of a vehicle 16 being carry towed.
In use, when the vehicle 16 is being carry towed, the
front wheels 14 of the vehicle are supported on support means
which is positioned be-tween the axes of the pairs of wheels
12.1 and 12.2 of the trailer as is shown in Figure 5.
Referring to Figure 7 of the drawings, the pairs of
wheels 12.1 and 12.2 are shown to be connected to the chassis
22 via arms 34.1 and 34.2 having stub axles 36.1 and 36.2
rotatably supporting the wheels of the trailer.
This embodiment also has retracting means lncluding
a hydraulic ram 38, having an anchor point 40 on the chassis,
and pivotally connected to the arms 34.1 at 42.1, and to the
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arms 34.2 at 42.2. The arms 34.1 and 34.2 are inter-
connected by connecting means 35 to ensure that the arms move
in unison. The chassis 22 may be raised and lowered relative
to the wheels and their supporting surface by displacing the
arms 34.1 and 34.2 in unison with their pairs of wheels about
their pivotal axes relative to the chassis 22, by means of the
ram 38.
Referring now to Figure 11 of the drawings, there is
shown an axial section through a trailer wheel 12. The wheel
10 12 comprises a pneumatic tire 100, a wheel rim 102 in the form
of two co-operating rim parts 104 and 106 mating along a plane
between the abutting flanges 104.1 and 106.1. The wheel rim
102 is secured by means of screws 108 to a mounting ring 110.
The ring 110 has openings 111 to receive the studs 112 for
15 securing the wheel to a brake drum 114.
The construction shown in the drawing was adopted so
as to be able to fit heavy duty brake drums to the small wheels
needed to run under a towed vehicle. It will be noted that the
diameter of the brake drum is substantially the same as that of
20 the tire 100 inside the opening within the beading 100.1.
The brake drum 114 has a spigot formation 114.1
fitting snugly into the cylindrical recess deEined by the inner
surface 104.1 of the rim part 104.
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It is an advantage of this invention that a
breakdown trailer is provided whereby even a heavy vehicle
which has broken down away from a garage, can be towed in
with safety by any towing vehicle having a coupler matching the
coupler 18 of the invention.
The embodiments of a carry towing trailer as
illustrated in the drawings, are less expensive, safer to
use and easier to operate than other towing vehicles known to
the applicant.
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