Note: Descriptions are shown in the official language in which they were submitted.
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SUPPORT LEG HEIGHT ADJUSTMENT DEVICE
FIELD OF THE INVENTION
The present invention relates to a support leg height adjustment device, and
more
particularly to a device for adjusting an overall height of the support legs
of a canopy
tent. The support leg each includes an upper support pipe telescopically
fitted in a
fixed lower support pipe. The height adjustment device includes a locating pin
that is
operated via a control lever to transversely extend through selected
positioning holes on
the lower and upper support pipes under a compression force of a coil spring,
so as to
determine the overall height of the support leg.
BACKGROUND OF THE INVENTION
One example of prior art adjustment device is disclosed in US Patent No.
6347777 as
shown in Fig. 4. The above-mentioned prior art adjustment device mainly
includes an
inner tube 30, an outer tube 32 telescopically fitted on the inner tube 30,
and a control
lever assembly externally mounted to the outer tube 32 for locking the inner
tube 30 to
a desired position relative to the outer tube 32. The inner and the outer tube
30, 32 in
an illustrated embodiment are square in their cross sectional shape, the inner
tube 30 is
provided on one side wall with a vertical line of spaced openings 36, and the
outer tube
32 is provided on a corresponding side wall with a pinning opening 39.
The control lever assembly or locating assembly mainly includes a lever 42
pivotally
mounted on top of a pivot bracket 44; and a spring 46 for biasing the lever 42
into an
operative position. The lever 42 is a generally flat, elongate plate-like
member having
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a middle section 48 and two opposite end sections 49, 50 each bent at an angle
to the
middle section 48. The middle section 48 is longer than either end section 49,
50; and
the end portion 50 is longer than the end section 49. A pinning button 52
projects
perpendicularly from one face of the end section 49.
In the above-mentioned prior art adjustment device, since the end section 49
of the
lever 42 is biased to the operative position by the spring 46 fitted on the
pivot bracket
44, a user has to constantly push the end section 50 against the outer tube 32
with one
hand, so as to resist a spring force of the spring 46 in the whole process of
adjusting the
position of the movable inner tube 30 in the fixed outer tube 32 and prevent
the pinning
button 52 from arbitrarily engaging with an undesired opening 36. When this
type of
adjustment device is used for the height adjustment of support legs of a
canopy tent 10
as shown in Fig. 1, it would cause a lot of inconveniences to the user 20.
SUMMARY OF THE INVENTION
A primary object of the present invention is to provide an improved support
leg height
adjustment device that is convenient for use to overcome the drawbacks in the
prior art
adjustment device.
To achieve the above and other objects, the support leg height adjustment
device
according to the present invention is used to set a movable first member of a
support leg
to different positions relative to a fixed second member, in which the movable
first
member is telescopically fitted. The movable first member is provided on a
side
surface in a sliding direction thereof with a vertical line of multiple spaced
positioning
holes, and the height adjustment device is transversely slidably connected to
one side
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surface of the fixed second member to engage with or disengage from any
selected one
of the positioning holes on the movable first member.
The support leg height adjustment device according to the present invention
includes a
hollow cylindrical sleeve internally defining a receiving space, the receiving
space
having a fully open first end and a partially closed second end; a locating
pin being
received in the receiving space of the cylindrical sleeve and having a front
end, a rear
end and an annular protruded portion provided on an outer surface thereof, and
the rear
end of the locating pin being outward extended through an opening defined at
the
partially closed second end of the cylindrical sleeve; a coil spring being
fitted on the
locating pin between the annular protruded portion on the locating pin and a
wall
portion surrounding the opening of the partially closed second end of the
cylindrical
sleeve; a riveted pivotal shaft being transversely extended through the rear
end of the
locating pin that outward extends through the partially closed second end of
the
cylindrical sleeve; and a control lever having two front forks, which are
connected to
two opposite ends of the riveted pivot shaft for setting the front end of the
locating pin
to a retracted position without hindering the movable first member of the
support leg
from sliding along its moving path in the fixed second member, and are able to
effectively bear a part of force applied to two sides of the riveted pivot
shaft.
The control lever is pivotally connected to the riveted pivot shaft, such that
when the
control lever is pivotally turned to a horizontal position aligned with the
locating pin,
the two forks press against the wall portion of the partially closed second
end of the
cylindrical sleeve, and the locating pin is constantly pulled rearward against
a
compression force of the coil spring to the retracted position without
hindering the
movable first member of the support leg from sliding along its moving path in
the fixed
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second member and does not become engaged with any undesired positioning hole
on
the movable first member.
When the control lever is pivotally turned to a position perpendicular to the
locating pin,
the locating pin is automatically pushed forward by the coil spring for its
front end to
extend through a selected one of the positioning holes on the movable first
member, so
that the movable first member is not slidable relative to the fixed second
member and
locked to a desired height to determine an overall height of the support leg.
The present invention is advantageous for use because the control lever in the
position
aligned with the locating pin constantly pulls the locating pin rearward
against the
compression force of the coil spring to move out of the sliding path of the
movable first
member without hindering the first member from sliding relative to the fixed
second
member, so that the user can easily adjust the first member to a desire height
without
the need of simultaneously pulling the locating pin backward with one hand;
and once
the first member is adjusted to the desired height, the user needs only to
pivotally turn
the control lever downward and the coil spring will automatically push the
locating pin
forward into two aligned positioning holes on the first and the second members
to set
the support leg to the adjusted height. This is because the control lever is
so
configured that a first distance between a pivot center of the control lever
and a front
end of the control lever is larger than a second distance between the pivot
center of the
control lever and a lateral side of the control lever, and a difference
between the first
and the second distance is larger than a third distance by which the front end
of the
locating pin can be extended into and through the positioning hole on the
movable first
member. Further, the control lever has a front end formed into two spaced
forks,
which are pivotally connected to two opposite ends of the riveted pivot shaft
to
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effectively bear a part of force applied to the transverse pivot shaft, so as
to achieve the
purpose of forcing the front end of the locating pin backward without
protruding into
the sliding path of the movable first member. When the control lever is upward
turned
about the pivot shaft to horizontally align with and pull the locating pin
backward and
out of the sliding path of the first member, the coil spring is compressed to
store a
compression force. Before the control lever is downward turned about the pivot
shaft
to be perpendicular to the locating pin, the locating pin will be constantly
maintained at
the backward retracted position against the compression force of the coil
spring without
arbitrarily extending into any undesired positioning holes on the first and
the second
member. And once the control lever is downward turned, the compression force
of the
coil spring automatically pushes the locating pin to an operative position
extending into
the selected and aligned positioning holes to set the support leg to the
desired height.
BRIEF DESCRIPTION OF THE DRAWINGS
The structure and the technical means adopted by the present invention to
achieve the
above and other objects can be best understood by referring to the following
detailed
description of the preferred embodiments and the accompanying drawings,
wherein
Fig. 1 is a perspective view showing a canopy tent having support legs
respectively
provided with a height adjustment device;
Fig. 2 is an enlarged view of the circled area in Fig. 1 indicated by arrow 2;
Fig. 3 is an exploded view of Fig. 2 showing the support leg height adjustment
device
according to an embodiment of the present invention;
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Fig. 4 is a sectional view of a conventional adjustment device;
Fig. 5 is a longitudinal sectional view taken along line 5-5 of Fig. 2 with
the support leg
height adjustment device of the present invention set to an operative
position; and
Fig. 6 is a longitudinal sectional view taken along line 5-5 of Fig. 2 with
the support leg
height adjustment device of the present invention set to a retracted position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will now be described with a preferred embodiment
thereof and
with reference to the accompanying drawings.
The support leg height adjustment device according to the present invention
can be used
with support legs for a canopy tent, which is very often used in different
outdoor
activities, such as sale exhibitions, picnic parties and the like. Fig. 1 is a
perspective
view of a currently available canopy tent 10, which includes multiple
telescopic support
legs respectively having a fixed lower support pipe 14 and an upper support
pipe 16
axially slidably received in the lower support pipe 14, so that an overall
height 12 of the
canopy tent 10 can be determined by locking the upper support pipe 16 to a
desired
position relative to the lower support pipe 14. Both of the lower and upper
support
pipes 14, 16 are provided with a vertical line of spaced positioning holes 18,
and one or
more positioning holes 18 on the lower support pipe 14 can be aligned with
selected
ones of the positioning holes 18 on the upper support pipe 16. A user may
engage the
support leg height adjustment device, which is generally denoted by reference
numeral
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22, with the positioning hole 18 on the lower support pipe 14 and controls the
height
adjustment device 22 to an operative position for immovably locking the upper
support
pipe 16 to a height relative to the lower support pipe 14 and thereby
determining the
overall height 12 of the canopy tent 10.
The structure and the operation of the support leg height adjustment device 22
of the
present invention for setting the relative position of the upper support pipe
16 to the
lower support pipe 14 to determine the overall height 12 of the canopy tent 10
are now
described with reference to Figs. 2, 3, 5 and 6.
The support leg height adjustment device 22 includes a suitably sized hollow
cylindrical
sleeve 54, which is fixedly welded or connected in any other suitable manner
at a front
end 56 to one side surface 58 of the lower support pipe 14, which has a
rectangular
cross-sectional shape in the illustrated embodiment. The cylindrical sleeve 54
internally defines a receiving space 60. The receiving space 60 has an open
first end
62 and a partially closed second end 64 defining a diameter-reduced opening 65
thereon.
The open first end 62 of the cylindrical sleeve 54 is located on the side
surface 58 of the
lower support pipe 14 around a selected positioning hole 18 thereon, with
which the
height adjustment device 22 is engaged. At this point, a locating pin 66 of
the height
adjustment device 22 received in the open first end 62 of the cylindrical
sleeve 54 and
the positioning hole 18 on the lower support pipe 14 are concentrically
located at the
same height. The locating pin 66 has a rear end 68 being dimensioned for fitly
rearward extending through the opening 65 on the second end 64 of the
receiving space
60 in the cylindrical sleeve 54, and a front end 70 for forward extending from
the
receiving space 60 into the positioning hole 18 on the lower support pipe 14
when the
height adjustment device 22 is in a retracted position as shown in Fig. 6, or
for
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extending through two aligned positioning holes 18 on the lower and the upper
support
pipe 14, 16 when the height adjustment device 22 is in an operative position
as shown
in Fig. 5 to determine the overall height 12.
Please refer to Fig. 6. To select a desired positioning hole 18 on the
slidable upper
support pipe 16 for aligning with a positioning hole 18 on the fixed lower
support pipe
14, a user 20 (see Fig. 1) may operate the height adjustment device 22 to the
retracted
position for the front end 70 of the locating pin 66 to disengage from the
positioning
hole 18 on the upper support pipe 16, so as to conveniently slide the upper
support pipe
15 upward or downward relative to the lower support pipe 14, as indicated by
the
double-head arrow 72, without the need of constantly pulling the locating pin
66
outward with one hand to prevent the front end 70 of the locating pin 66 from
extending
into any positioning hole 18 on the upper support pipe 16 as shown in Fig. 5.
To enable convenient operation of the height adjustment device 22 to achieve
the above
purpose, the locating pin 66 is externally provided at a predetermined
position with an
annular protruded portion 74, which has a radially thickness about 1/3 of an
outer
diameter of the locating pin 66, and is mechanically processed at two
diametrically
opposite sides of the rear end 68 to form two corresponding flat wall surfaces
76. And,
a bore 78 is provided to transversely extend through the locating pin 66
between the two
flat wall surfaces 76. The above-described structure can be best seen from
Fig. 3. A
coil spring 80 is fitted on the locating pin 66 between the annular protruded
portion 74
and a wall portion of the partially closed second end 64 surrounding the
opening 65. A
pivot shaft 82 of a rivet 84 is transversely extended through two aligned
holes 86
provided on two front forks 90, 92 of a control lever 94 and bearings 88 in
the holes 86.
The rear end 68 of the locating pin 66 extended through the opening 65 is
located
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between the two forks 90, 92 of the control level 94. For the control lever 94
to
pivotally rotate about the riveted pivot shaft 82 by 90 degrees into the
operative
position shown in Fig. 5 or into the retracted position shown in Fig. 6, the
forks 90, 92
coaxially connected to the rear end 68 of the locating pin 66 via the riveted
pivot shaft
82 have front end surfaces in the form of cams or being particularly curved.
As can be
best seen in Fig. 6, when the control lever 94 is pivotally turned to a
horizontal position
for the cam-shaped front end surfaces 96 of the two forks 90, 92 to press
against the
wall portion of the second end 64 of the receiving space 60 in the cylindrical
sleeve 54,
the height adjustment device 22 is set to the retracted position and the
locating pin 66 is
pulled rearward against a compression force of the coil spring 80 to move its
front end
70 out of the positioning hole 18 on the upper support pipe 16. In the
retracted
position shown in Fig. 6, a gap is formed between the front end 70 of the
locating pin
66 and the axial moving path 72 of the upper support pipe 16, so that the
locating pin 66
does not hinder the upper support pipe 16 from sliding upward or downward as
indicated by the two-head arrow 72. At this point, the user 20 can adjust the
support
leg to a desired height simply by sliding the upper support pipe 16 upward or
downward
relative to the lower support pipe 14. When the desired height 12 is reached,
the user
needs only to downward pull the control lever 94 at a rear end 98 thereof to
set the
height adjustment device 22 to the operative position, and the compression
force of the
coil spring 80 will automatically push the locating pin 66 through the
positioning hole
18 on the upper support pipe 16, as shown in Fig. 5.
The present invention has been described with a preferred embodiment thereof
and it is
understood that many changes and modifications in the described embodiment can
be
carried out without departing from the scope and the spirit of the invention
that is
intended to be limited only by the appended claims.
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