Note: Descriptions are shown in the official language in which they were submitted.
2 a ~
~LQu~d of the Invention
This invention relates to an improved single wheel
trailer for a bicycle, particularly an operator
propelled single wheel trailer.
Single wheel bicycle trailers of various types are
known in the art although they appear not to have met
with a wide degree of commercial success, at least in
North Ameri~a. The following patents exemplify the ~tate
o the art:
U.S. Patent~
3,787,065 Grimm
4,413,835 Hazelett
- , ,
4,458,90~ Strong ~ m~
4,756,541 Albitr~
15Canadian Patents
51,516 Jakobson
1,235,435 Bertrand
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The broad concept o~ a.:.:tandem bicycle is not new
reference being had to the Stron~ U.S. Patent~4,458,g08.
One might also refer to the old Canadian patent 51,516
dating from March 3, 1886. In both of these patents, the
trailing bicycle uses elther its own forks or a modified
set o~ forks. The Strong U.S. patent provides a special
set of forks which are connected to the rear a~le of the
leading bicycle with the upper end of the forks being
provided with a universal joint permitting relative
movement between the bicycles about three different axes,
i.e. pitch, yaw~ and roll. The mechanism allows
simultaneous tilting, bending and articulating between
3Q the two bicycle sections. The con~c~ion is of a
somewhat complicated nature -invol~ing ~pring~ etc. which
we need not describe in detail at the present time.
: The above li~t of patents al~o includes several
single wheel trailer bicycle attachments. Reference may
be had to U.S. patents 4,413,835, 4,756,541 and Canadian
1,~35,435. The Canadian patent, for example, discloses
2 ~ ~ 3 ~ d
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a connection between the trailer and the bicycle which
permits relative movement between the bicycle and trailer
about the pitch (horizontal) and yaw (v~r~ical) axes.
The reasons behind the lack of commercial success
appear to be that, while certain of the prior art designs
included ~ne or more useful features, no one seems to
have been able to put together in one assembly that
combination nece~sary to provide a high performance,
stable, sae, simple and readily affordable operator-
propelled single wheel bicycle trailer. The above-noted
characteristics (of sa~ety and stability) are especially
important when considering the fact tha young families
will be using these trailer systems; a common arrangement
will involve a parent driving the usual bicycle with th~
child on the trailer. Affordability and adaptability to
virtually any commercially available bicycle are also key
considerations for a commercially successful arrangement.
SummarY o~ the Inventlon
A basic object of the invention is to provide a
stable, safe, simpl~ and cost-affordable single wheel
bicycle trailer which eliminat~s or at lea~t alleviates
many of the disadvanta~es of the presently known prior
art bicycle trailers of thi~ type.
The invention in its several aspects is defined in
the claims appended hereto.
DescriPtion of the Views of Drawin~~
Fig. 1 is a side elevation view of the single wheel
trailer o~ the present invention secured to a
conventional bicycle;
Fig. 2 is a view, partly in section, of the
connection between the trailer and bicycle;
2~3~6
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Fig. 3 is a plan YieW of the connection of Fi~. 2;
Figs. 4 and S are ront and side elevations of the
adjustable handle bar and its mounting;
Fig. 6 is a view similar to Fig. 1 ~howing a
modified form of si~gle trailer (youth or child version).
Detailed Description
Referring now to the drawings, there is shown in
Figure 1, a single wheel bicycle trailer 10 in arcordance
with one embodiment of the invention (the adult ver~ion)
secured to a ~onventional bicycle 12. The trailer 10
includes a main frame 14 of welded tubular members, this
main frame including a generally upright seat pos~ 16
with the trailer wheel 18 being rotatably mounted to
frame members 20 rearwardly of the seat post 16. A
crossbax 22 is welded to and extends forward from an
upper end portion of the seat post 16. A brace 24
extends downwardly and rearwardly ~rom the crsssbar 22
and i~ fixed relative to the lower end o~ seat post 16
to stabilize the crossbar. (The lower end of ~eat post
20 16 and the lower end of brace 24 are actually both welded
to a housing (not shown) which rotatably mounts the
conventional crank and sprocket as~embly 26~.
The arocsbar 22 has a forwardly directed elongated
extension 28 which has a distal end 30. A flexi~le
25 connector 32 to be described in detail hereafter, is
secured to distal end 30 to effect a connection to the
bicycle 12. This 1exible connector 32 provides freedom
of movement of the bicycle 12 and trailer 10 relative to
on~ ano~her about mutually tran~verse pitch and yaw
30 axes.
Turning now to Figures 2 and 3, the seat post 16 is
provided with an upwardly extending ~tem 34 which
~upport~ a con~entional b1cy~le ~eat 36. The }lexible
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connector 32 includes a bracket 36 mounted on the stem
and rotatable about the longitudinal axis of the stem to
provide the above-noted freedom about the yaw ax~. In
order ko facilitate this rotating motion, the bracket and
stem are provided wi~h upper and lower ball bearing
~ssemblies 38 and 40 with the stem being provided with an
annular shoulder 42 which limits the downward mov~ment of
the bracket and its bearing assembly. The ~tem is also
thread~d as at 44 to accommodate a lock nut 46 which
secures the whole bearing assembly together.
The trailing end portion of bracket 36 is bifurcated
and ~haped to receive the distal end portion 30 of the
crossbar extension 28. A pivot pin .~0 defines the
horizontal transverse pivot connection betw2en bracket 36
and the distal end of the extension 28 thereby to proYide
the above-noted freedom o movement about the pitch axis.
It might be observed here that the angle of incline
of the seat post 16 and stem 34 relative to the
horizontal provides for a natural castering effect of the
flexible connector thereby reducing side thrusts during
operation. When the lead bicycle leans to go around a
corner, the trailer tends to lean slightly opposite
(about 15). In the sharpest corner the lead bicycle
might be expected to negotiate, the trailer be~omes
~enerally vertical. This factor makes for greater
stability, a~; in a situation where the road is slippery
and excessive leaning could cause the wheels to slide out
~rom underneath the rider.
With reference to Figures 4 a~d 5, the trailer is
provided with a handle b~r 54 which is secured to the
crossbar 22 hy way of a handl~ bar mounting stnlt 56.
The strut comprises an elorlgated bar o~ metal of 'che
correct approximate length which is provided at its lower
end with a semi-circular recess 58 to receive the cros~
35 bar. A corresponding cap portion 60 also has a
2~53~4g
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corresponding semi-circular rece~s therein, the cap 60
being secured to the mounting strut 56 via cap screws 62
and which, when tightened, securely fix the mountiny
strut 54 relative to the trailer frame. By loosening cap
screw 62, the mounti.ng strut 56 c~n be slid toward and
away from the seat 36 thereby to accommodate differently
sized riders.
The upper end of strut 56 is provided with
transverse aperture to receive the handle bar 54 with a
slot 64 leading into the aperture and a cap screw 6~
being provided to securely fix the handle bar 54 relative
to the strut 56.
It might be noted that, as illustrated in Fig. 1,
when the trailer is attached to the leading bicycle, the
crossbar 22 inclines slightly upwardly and forwardly from
the ~eat post 16. Hence, as the handlebar mount is
adjusted away from the seat po~t, the handlebar is
automatically raised upwardly thereby to better
accommodate lar~er riders on the trailer. The seat 36
can of course be raised and lowered .in conventional
~ashion to accommodate larger or smaller riders as the
case may be. This situation is more pronounced in the
F.ig. 6 version where the crossbar 122 is secured to an
intermediate portion of the seat post 116 and slopes
steeply upwardly and forwardly therefrom. This provides
greater degree of height adjustment for the handle bar~
and makes this version more suitable for small size
(childrens) frames.
The trailer 10 is also provided with a conventional
crank and sprocket means 26 drivingly connected to the
conventional cycle wheel 18 by chain and ~procket
assembly 60. ~he chain drive assembly is typically
provided with a conventional gear change mechanism
compatible with the gear change m~chanism on the leading
bicycle for obvious reasons.
~ 3
While a preferred embodiment of the invention has
been described by way of example, those skilled in this
field will realize that numerous modifications and
changes may be made while still remaining within the
scope of the lnvention. Accordingly, the invention is
not to be limited to the speciic embodiment described
but is to include all modifications and variations as
fall within the scope of the accompanying claims.
