Note: Descriptions are shown in the official language in which they were submitted.
11~1423
2.
This invention relates to traction jockey wheels
of a type useful for supporting and assisting movement
of towed vehicles such as caravans or trailers.
I have developed wheels of this type some aspects
of which have been subject of previous patent
applications and granted patents such as United States
Patent No. 42277~6. Ihe~ Lnclude a pawl and ratchet wheel in
which the ratche-t wheel is co-axially secured to a
ground engageable wheel and preferably there is an
adjustably positioned pawl secured to a supporting
frame and a second adjustably positioned pawl secured
to an operating lever arm which in itself is pivotally
secured about an axis co-axiAl with the ratchet wheel.
Both of the pawls are adjustably positioned so
that in one position, movement of the operating lever
arm can effect drive of the ratchet wheel in a first
direction about its axial support and thereby cause
the traction wheel to rotate and hence any supported
towed vehicle and by otherwise positioning each of the
pawls, movement of the operating lever arm can be made
to effect rotation of the ratchet wheel and hence the
traction wheel in an opposite direction.
Such a drive mechanism can be duplicated so that
there can be two ground engageable traction wheels and
by having these separately rotatable and separate
pawls for each of the ratchet wheels, a differential
effect providing for ease in steerability can be
achieved.
11~1423
This differential effect can be achieved wlth
drive on each wheel so that there is advantage in
a two wheel arrangement although the drive mechanism
- is not directed exclusively either to a single wheel
or to a dual whee] system.
The problem to which this invention is directed
relates to a difficulty that can be e~perienced
when using either of the above mechanisms.
If in any instance the towed vehicle commences
to move under its own impetus in the direction that is
otherwise selected for the pawls then there is no
inhibition by reason of the drive mechanism to
movernent in this direction.
This can perhaps be better understood by
appreciating the problem that can occur with a large
caravan which is pulled by using the traction ;jockey
wheel mechanism to the peak of a hill but as the hill
is reachecl, commences under its OWIl weight to move
down the hill.
In this circumstance, neither of the ratchet
settings of the pawls would inhibit this movement ancl
a dangerous situation could arise if the person
operating the traction jockey wheel should happen to
fall then there is a real possibility that the vehicle
could proceed without his guidance and he in fact
could be in danger of being hit or even run over by
the vehicle.
According to this invention this problem is
overcome by providing that with the drive mechanism
there is provided a brake means, and a brake control
4.
arrangement arranged so that in a first selected range of
positions of the lever arm, the brake means are held in a
non-braking position, and in its second range of positions
of the lever arm the brake means are released so they may
assume a braking position with respect to the raction wheel
or wheel 5 .
According to the present invention there is
provided a traction ~ockey wheel for supporting and moving
towed vehicles, said jockey wheel including a supporting
frame for attachment to said vehicle, a traction wheel
supported by said frame and notable relative thereto about a
generally horizontal axis, and means to control rotation of
said wheel relative to said frame said means including a
manually operable drive member supported on said frame for
oscillatory movement relative thereto, a ratchet mechanism
operable between said drive member and said traction wheel
to in,part rotation to said wheel upon oscillatory movement
of said drive members through a predetermined range, brake
means operable to inhibit rotation of said wheel relative to
said support, and movable between operative and inoperative
positions, said brake means being connected to said drive
member to move from said inoperative to said operative
position upon movement of said drive member beyond said
predetermined range.
~l~i423
4a.
It is a characteristic of this arrangement that
the operating lever arm is used both to effect a drive
of the traction wheel and is also used for steering.
.
The operating range of positions of the lever arm
relates therefore to the range of positions of the
lever arm with respect to the support frame of the
traction jockey wheel so that the steering control
position of the lever arm is then not relevant.
This could however include rotation of the lever
arm about its elongate axis against a spring return
pressure or it could include in a preferred instance
enabling a braking means to assume an effective
braking position when the lever arm is in an uppermost
relative position to the support frame or in a
lowermost position.
It will be understood that the more important of
these positions is the lowermost position in that if a
person should happen to fall then the lever arm is
allowed to fall also and upon this reaching a
lowermost position that is typically with the lever
arm engaging the ground then clearly this will allow
the brake to engage and impede an otherwise dangerous
situation developing.
23
.,
There is value in having the lever arm uppermost
with a braking effect in that this can be an assured
storage position in which the lever arm is in
effectively a storage position and the traction wheels
are then effectively in a locked condition.
This concept can apply in either of the cases
where either there is a single traction wheel or there
are two traction wheels co-axially supported.
Indeed there is no limit to the number of wheels
that can be co-axially supported although two has been
found to be a preferred number.
With the two tractipn wheels, in a preferred
instance, there can either be a separate mechanism for
each wheel including a separate braking means
independently operating or there can be a commonly
applied braking member as will be illustrated in the
preferred embodiment.
For a better understanding oE this invention it
will now be described with the assistance oE drawings
in which:-
FIG. I is a perspective view oE a traction jockeywheel according to a Eirst preEerrecl embodiment having
a part of one oE tne traction wheels cutaway for
clearer visibility;
423
FIG. 2 iS a side elevation of the traction jockey
wheel as in FIG. 1 according to the first embodiments viewed
on the line 2-2 of FIG. l;
FIG. 3 is a cross sectional side elevation on the
line 3-3 of FIG. 1 showing the operating lever arm in a
position whereby the braking means are in a non-braking
position;
FIG. 4 is a view identical with that as shown in
FIG. 3 of the first embodiment except that the lever arm is
shown in a position in which the braking means are in a
braking position and finally,
FIG. 5 is a ~ide elevation of a second em~odiment
providing the mechansim and level arm assembly for a single
traction jockey wheel.
Referring now in detail to the drawings and
referring firstly to the first preferred embodiment as
illustrated in FIGS. 1 through to 4 this includes a traction
jockey wheel 1 which includes a support frame 2 and
supported from this two traction wheels which are
independently rotatable 3 and 4 each on a common axis 5 and
each held in position by a spring washer 6.
Secured co-axially with respect to each of the
traction wheels 3 and 4 is a ratchet wheel 7 and 8 so
arranged that each of the ratchet wheels are co-axial with
the respective traction wheel and secured so as to rotate
co-axially therewith.
B
Z3
With respect ot each of the ratchet wheels 7 and
8 are spring loaded pawls which are adjustably
supported in the case of pawl 9 by a lever arm
assembly 10 and in the case of pawl 11 by the support
frame 2. Likewise in the case of pawl 12 which is not
shown this also being supported by ]ever arm assembly
and in the case of pawl 13 this is adjustably
supported by support frame 2 both o.E these in respect
of ratchet wheel 8.
Each of the pawls is pivotally supported with
respect to the respective mounts and includes a spring
loaded plunger 14 wh.ich acts,against member 15 which
includes at an upper edge a concave face 16 ancl at a
lower edge fingers 17 and 18 the member lS being
pivotally supported with respect to the respective
support member.
It will be seen by the use oE this arrangement
that by co-operatively adjusting each of tlne pawls in
position, so that each will provide a ratchet .Ereeclom
in one directi.on and a l.ock against movement of the
ratchet wheel in the other then this will ensure
forward or reverse movement depending upon the
adjustable position selected wllen the lever arm
assembly 10 is moved relative to the support frame 2.
It is to be noted that :in ~IG. L the lever arm
assembly includes a spigot 19 to which an extension
comprising a hollow lever member can be secured to
provide substantial leverage and steering control when
necessary.
~ 4L~3
The support frame 2 further includes an
extendible stem 20 and a control handle 21 controlling
the degree of extension of the stem 20.
To provide a braking effect when necessary there
is provided a braking member 21 which includes a tooth
22 and which is pivotally supported with respect to
the support frame 2 about an axis at 23 which
coincides with the axis of the member 15 where this
secured to the support frame 2.
A spring member 24 is secured to the support
frame 2 at 25 and is so arranged so as to bias the
movement of the brake member 2:1. so that it will bc
urged into a braking pos:ition that is with the tooth
22 lnterlock;.ng with respect to the teeth 26 o.E the
ratchet wheel 8.
This of course is repeatecl in the same manner
with ratchet wheel 7.
The inter:Lock:ing posit:ion of the braking member
21 is however controlled by the efEective inter-
relationship of the l.eg 27 wh:ich :is secured at an endof the lever arm arrangement lO and this engages
against a cam base 28 which is so shaped that when it
is in the position as shown in .FIG. 3 this will hold
the tooth 22 from interlocking and therefor in a
non-braking position but when it is moved up into the
position either at 29 or 30 then this will allow for
the tooth 22 to move to a interlocking position and
hence a braking position with respect to the traction
wheel 4.
This position is most clearly shown in FIG. 4 in
which the lever arm assembly 10 is shown in a
lowermost position whereupon allowing tooth 22 under
the i.nfluence of spring 24 to assume an interlocking
position with respect to the teeth 26 of the ratchet
wheel 8.
~,~
It will be seen from this that there a,~e a range
of positions over an operating range that the lever
arm assembly 10 can work through but this can then be
shifted to a lowermost position which will normally
not be used when normally effecting a drive of the
traction wheels or in an uppermost position as shown
i.n ~IG. 1 WhiCIl iS generally a storage position which
is also a position not normally assumed when the
wheels are be:ing clriven.
Now referring to the second embodiment as shown
in FIG. 5, this relates to the mechanism which is used
in conjullctioll with a sing:le traction wheel
According:ly the support .Erame 3:L includes an
extendible stenl 32 only part of whi.ch :is shown for
sal<e of simpl:icity and a yoke 33 which extends with
legs to support the frame 31 on both sides of the
traction wheel 34 by engaging support axial 35.
A lever arm assembly 36 with appropri.ately
adjustable pawls 37 and 38 which are not fully shown
but which operate and are arranged i.n identical
fashion to that shown in the first embodiment
operatively interconnect in the same way as in the
first embodiment with the ratchet wheel 39 so that in
one position operation of the lever arm assembly 36
with the lever ~
23
10 .
arm extension in this case 40 will effect drive in one
direction wlth the pawl 38 supported by the support
frame 31 by reason of its pivot support on a portion
of the leg of the yoke 33.
The addition in this case includes a brake member
41 which is pivotally supported about the axial
support 42 which is secured relative to the yoke 33
which is a part of the support frame 31 and this drive
member 41 is urged :into a braking position by reason
of spring element 43 which has an end secured by
passing through an aperture a,t 44.
The brake member 41. has a tooth 45 which is
adapted to interlock with the teeth 46 o:E the ratchet
wheel 39.
This is inhib.ited by reasoll of the leg 47
engaging agai.nst the cam .Ence 43 o.E thc drive member
4:1.
If however the leg 47 reaclles portions 49 or 50
then of course this allows the position of the drive
member 41 to SWillg in the direction of the spring
pressure caused by 43 which causes an interl.ock of the
ratchet wheel and hence the traction wheel 34 with
rcspect to ~he support .Erame 31.
23
11 .
This then describes the preferred embodiment
from which it will be seen that by incorporation
of a braking means and control means relative to
the braking member operable so that a braking effect
is achieved when the lever arm is in an other than
selected range of positions then this provides a
very good safety factor and provides for significant
improvement in relation to this concept.
