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Patent 2504432 Summary

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(12) Patent Application: (11) CA 2504432
(54) English Title: EXTENSION LADDER WITH IMPROVED STRUCTURE
(54) French Title: ECHELLE A PERCHES AVEC STRUCTURE AMELIOREE
Status: Dead
Bibliographic Data
(51) International Patent Classification (IPC):
  • E06C 1/30 (2006.01)
  • E06C 1/12 (2006.01)
(72) Inventors :
  • YAO, KUO-CHING (Taiwan, Province of China)
(73) Owners :
  • YAO, KUO-CHING (Taiwan, Province of China)
(71) Applicants :
  • YAO, KUO-CHING (Taiwan, Province of China)
(74) Agent: NORTON ROSE FULBRIGHT CANADA LLP/S.E.N.C.R.L., S.R.L.
(74) Associate agent:
(45) Issued:
(22) Filed Date: 2005-04-20
(41) Open to Public Inspection: 2006-10-20
Availability of licence: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): No

(30) Application Priority Data: None

Abstracts

English Abstract




An extension ladder with improved structure includes a
plurality of ladder sections, connection kits, locking
mechanism, and transverse step portions wherein each ladder
section is a hollow rung, and the caliber of the rung becomes
smaller when it is in a higher location. The upper ladder
section and lower ladder section can be interconnected and
fit each other; said connection kits are horizontally provided
in the upper end of said ladder section. The internal part
of said connection kit is provided with a locking mechanism
to snap-fit into the through hole of said ladder section to
secure the extension between each ladder section. The outside
of said locking mechanism is covered by the transverse step
portion, by which the ladder can be assembled conveniently
and securely, appliance safety can be improved, and ladder
life can be prolonged.


Claims

Note: Claims are shown in the official language in which they were submitted.



WHAT IS CLAIMED IS:
1. An extension ladder with improved structure, comprising:
A plurality of ladder sections, connection kits, locking
mechanism, and transverse step portions, wherein each ladder
section is a hollow rung having different caliber, which can
be interconnected by fitting each other and pulled and
extended; its upper end is horizontally provided with a
connection kit, while the inside of said connection kit is
provided with a locking mechanism covered by said transverse
step portion.
2. The extension ladder with improved structure as claimed
in claim 1, wherein said ladder section and connection kit
are adhered to each other by engaging the orientation hole
on the ladder section with the orientation tenon of said
connection kit, and then infusing the adhesive into the
adhesive channel on the inside of said connection kit.
3. The extension ladder with improved structure as claimed
in claim 1, wherein the joint part of said ladder section and
connection kit is provided with a orientation hole to
interconnect with the through hole of said connection kit,
so that the locking bar of the locking mechanism in the internal
part of said connection kit can be moved forward and backward



to the predetermined position through the joint part.
4. The extension ladder with improved structure as claimed
in claim 3, wherein said connection kit is connected with the
ladder section by means of the ringlike covering part, and
the pivotal joint on the connection kit is provided with a
locking mechanism.
5. The improved extension ladder apparatus as claimed in claim
4, wherein said locking mechanism is inserted into the pivotal
joint by means of the locking gate, so that the sleeve in the
middle of said locking gate is placed in the channel of said
pivotal joint; said sleeve is provided with a spring and a
locking bar, and the locking bar should pass through the
through hole of said pivotal joint to the orientation hole
of said ladder section.
6. The extension ladder with improved structure as claimed
in claim 5, wherein said locking mechanism can control the
onward and backward movement of the locking bar by means of
a fork-shaped turning rod.
7. The extension ladder with improved structure as claimed
in claim 1, wherein the bottom segment of said ladder section
is provided with a through hole for the locking mechanism of
11


said external ladder section to insert therein when the
external ladder section and said ladder section are extended
to use relatively.
8. The extension ladder with improved structure as claimed
in claim 7, wherein said ladder section is provided with a
blocking ring having a relatively large caliber in the
position above the through hole; when the external ladder
section is extended and used, the blocking ring is firmly
against the inwardly protruding ring of the connection kit
in the external ladder section, which ensures that the through
hole is located in the position relative to the orientation
hole, via hole, and locking bar.
9. The extension ladder with improved structure as claimed
in claim 1, wherein the lower end of said ladder section is
provided with a sleeve-shaped buffering device, and an elastic
seal ring is provided on the bottom outer rim of said buffering
device to maintain friction when it contacts with the inside
of said rung, and to reduce noise and slow down the folding.
10. The extension ladder with improved structure as claimed
in claim 9, wherein the inside of said buffering device is
provided with a mylar, on which a hole is formed to enhance
the cushion effect by allowing airs to enter into the cavity
12



of said mylar via the holes when the buffering device moves
upward and downward.
13

Description

Note: Descriptions are shown in the official language in which they were submitted.



CA 02504432 2005-04-20
EXTENSION LADDER WITH IMPROVED STRUCTURE
BACKGROUND OF THE INVENTION
Field of the invention
The present invention relates to an extension ladder, and
more particularly to an extension ladder apparatus, which is
assembled easily and securely, providing superior safety.
Description of the Prior Art
Accordingly, stepladders have become a requisite tool for
casual use. For example, climbing tools such as a ladder or
scaffolding enable people to readily process construction or
obtain the objects at a high place.
A conventional stepladder 800, as shown in FIG. 1, is
assembled by two ladder sections having a footpad respectively
to prevent slippage, and is provided with parallel spaced step
portions therein. The stepladder appears as an A-frame ladder
during usage.
Stepladders are typically large and bulky therefore, it
is uneasy and inconvenient to carry them. Moreover, the
storage of a folded stepladder may occupy large space, which
makes the use of a stepladder inflexible.
Accordingly, the present invention has been invented to
solve the above-mentioned problems occurred in the prior art.
1


CA 02504432 2005-04-20
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to
provide an extension ladder with improved structure, which
is composed of multi-segment ladder sections, connection kits,
locking mechanism, and transverse step portions, providing
ease and convenience to fold and take along, store, or unfold
and use.
In the extension ladder apparatus according to the
present invention, the connection kits and hollow rungs are
locked in place, and then stuck and fastened. This prevents
these components from loose and disattachment, which serves
as another object of the present invention.
The extension ladder apparatus according to the present
invention, in which the locking mechanism provided inside the
connection kits are wrapped by transverse step portions, and
can avoid the damage of rust, which serves as further object
of the present invention.
The detailed structure, application principle, function,
and effects of the present invention will be more apparent
from the following descriptions taken in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION QF THE DRA4JINGS
2


CA 02504432 2005-04-20
FIG. 1 is a three-dimensional view of the conventional
extension ladder;
FIG. 2 is a three-dimensional view of the present
S invention;
FIG. 3 is a three-dimensional view showing the folding
and unfolding of the push rod in the present invention;
FIG. 4A is a three-dimensional exploded view showing the
ladder section and transverse step portion in the present
invention;
FIG. 4B is a three-dimensional assembly view showing the
partial construction of the present invention;
FIG. 5 is a three-dimensional assembly view showing the
ladder section and transverse step portion in the present
invention;
FIG. 6 is a sectional view showing the assembly of the
ladder section and transverse step portion in the present
invention; and
FIG. 7 is a sectional view of the embodiment in the present
invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
The extension ladder with improved structure in the
3


CA 02504432 2005-04-20
present invention, as shown in FIG. 2, wherein the extension
ladder 1 is foldable, or unfoldable as shown in FIG. 3, includes
a plurality of ladder sections 2, connection kits 3, and
transverse step portions 5. The stepladder appears as a rising ,
S ladder when it is unfolded and used, and can be folded by
fitting the ladder sections with different calibers one
another.
Referring to FIG. 4 and 5, each ladder section 2 fits each
other by providing similar-shaped but smaller internal ladder
sections 2a. Said cannular-shaped ladder section 2 is provided
with a snap-fit hole 21 and a orientation hole 22 on its upper
end, and provided with a through hole 23 and opening 24 on
its lower end. Also, a blocking ring 25 is provided on the
upper end of said through hole 23 at proper height.
~ The connection kit 3 has a ringlike covering part 31 and
a pivotal joint 32. Said ringlike covering part 31 is
horizontally provided on the upper end of the ladder section,
and affixed to the ladder section by fastening'a screw therein.
A plurality of orientation tenons 34 are provided on the inside
of said connection kit for engaging with the snap-fit hole
21 of said ladder section, so that the connection kit can be
assembled with the ladder section quickly. Also, the inside
wall of said connection kit is provided with an adhesive
channel 35, wherein the adhesive are infused into the
adhesive-infusing hole 36 on its one end so that the connection
4


CA 02504432 2005-04-20
kit can be firmly adhered to the ladder section 2. Moreover,
a via hole 30 is provided on the connection kit for
interconnecting with the internal channel 3? of said pivotal
joint 32.
S Said pivotal joint 32 is integrally molded with the
ringlike covering part 31, and its internal channel 37 can
be passed through. A groove 38 is provided in the end of said
channel 37 for loading the locking mechanism 4.
Said locking mechanism 4, as shown in the figure, includes
a locking gate 41, a locking bar 42, a spring 43, and a turning
rod 44; two wings of said locking gate 41 is provided with
a plug plate 411 and 412 respectively, and its center is
provided with a sleeve 413. When the plug plate 411 and 412
on said locking gate are inserted into the groove 38 of the
pivotal joint, the sleeve 413 is directly in the channel 37
of said pivotal joint. The inside of said sleeve 413 is provided
with a spring 43 and a locking bar 42, while one end of said
locking bar is firmly against the spring 43 and the other end
directly faces the via hole 30 of ringlike covering part and
the orientation hole 22 of said ladder section. An axle center
421 with a smaller caliber is provided in the middle of said
locking bar, so that the turning rod 44 can be inserted therein
and twisted. The tenons 441 on two bottom sides of said turning
rod 44 are provided into the predetermined groove of said
pivotal joint for orientation. Also, a fork-shaped wiper blade
5


CA 02504432 2005-04-20
442 on one end of said turning rod is inserted into said axle
center 421 to control the onward and backward movement of said
locking bar 42.
When the locking mechanism 4 is installed in the pivotal
joint 32, the transverse step portion 5 is then provided onto
the outside of said pivotal joint 32. The side wall end of
said transverse step portion 5 is provided with a cross hole
51 for the turning rod 44 to extend out forwardly for the twist
and control.
In addition, the lower end of the hollow rung 21 is provided
with a sleeve-shaped buffering device 6. The upper end of said
buffering device, by means of a hooked tip 61 provided thereon,
is affixed to the opening 24 of said ladder section 2. The
lower-end outside of said buffering device is provided with
an elastic seal ring 62 to increase friction when it contacts
with the inside of said rung and reduce noise. Also, as shown
in FIG. 6, the internal part of said buffering device is
provided with a mylar 63 with its surface having a hole, which
allows airs to enter the cavity of said mylar 63 when the
buffering device 6 moves upward and downward, and thus
enhances the cushion effect.
When the assembling has been completed, as shown in the
figure, the bottom of the ladder section 2 is provided with
a buffering device 6 and an elastic seal ring 62 to increase
the friction between the ladder section and the inside wall
6


CA 02504432 2005-04-20
of internal ladder section, so that the purpose of slowing
down the descending can be achieved. Also, the connection kit
and the upper end of said ladder section are provided with
adhesive channel 35 to infuse the adhesive therein, so that
the connection kit and the ladder section can be adhered to
each other. Accordingly, the present extension ladder is
assembled integrally and securely: Moreover, the provided
locking mechani$m 4 is fully covered by the connection kit
3 and the transverse step portion 5, which not only makes it
easy and convenient to control the locking mechanism, but also
prevents the damage caused by any foreign object.
As shown in FIG. 6, when the internal ladder section 2a
and ladder section 2 are extended to use relatively, the
blocking ring 2a1 having a larger caliber on the outside of
said internal ladder section 2a is firmly against the inwardly
protruding ring 311 of said connection kit in the external
ladder section. Meanwhile, the through hole 2a2 on the lower
end of said internal ladder section 2a is directly located
in a route having the orientation hole 22 of said external
ladder section, via hole 30 of said connection kit, and locking
bar 42 a, which enables the locking bar 42 to be inserted in
the fixed position smoothly when it is moved forward.
In the following description and drawings, different
reference numerals are used to designate different components.
When a stepladder is folded, as shown in FIG. 7, the first-level
7


CA 02504432 2005-04-20
turning rod 71 is twisted backward to force the locking bar
72 to withdraw from the through hole of second ladder section
73. Then, the second ladder section 73 falls downward along
with the second transverse step portion 74 owing to a lack
of any obstruction. Similarly, if the turning rod 75 is twisted
backward, the locking rod 77 shall be forced to withdraw from
the through hole. Then, the third ladder section 78 together
with the third transverse step portion 79 falls down
consequently. On the analogy of this, all rung sections and
step portions can be folded quickly.
Accordingly, the extension ladder with improved structure
in the present invention are integrally assembled securely
by providing a snap-fit hole 21, orientation tenon 34, and
blocking ring 25 between the connection kit 3 and ladder
section 2 for quick and correct orientation. Also, the ladder
assembly can be securely by providing with the adhesive
channel 35. Furthermore, the locking mechanism 4 is provided
on the connection kit 3 for making the assembling more
convenient, the control of the ladder easier, and prolonging
ladder life.
As described above, the extension ladder apparatus in the
present invention certainly enhances appliance safety, and
makes folding and using quick.and convenient, which can
improve the deficiencies of conventional ladders. Also, the
present invention has not yet opened to public, it is then
8


CA 02504432 2005-04-20
complied with the conditions of allowable patents.
Although the above-mentioned embodiments of the present
invention have been described for illustrative purposes,
those skilled in the art will appreciate that various
modifications, additions and substitutions are possible,
without departing from the scope and spirit of the invention
as disclosed in the accompanying claims.
15
25
9

Representative Drawing
A single figure which represents the drawing illustrating the invention.
Administrative Status

For a clearer understanding of the status of the application/patent presented on this page, the site Disclaimer , as well as the definitions for Patent , Administrative Status , Maintenance Fee  and Payment History  should be consulted.

Administrative Status

Title Date
Forecasted Issue Date Unavailable
(22) Filed 2005-04-20
(41) Open to Public Inspection 2006-10-20
Dead Application 2009-04-20

Abandonment History

Abandonment Date Reason Reinstatement Date
2008-04-21 FAILURE TO PAY APPLICATION MAINTENANCE FEE

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Application Fee $400.00 2005-04-20
Maintenance Fee - Application - New Act 2 2007-04-20 $100.00 2007-04-12
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
YAO, KUO-CHING
Past Owners on Record
None
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
Documents

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Document
Description 
Date
(yyyy-mm-dd) 
Number of pages   Size of Image (KB) 
Cover Page 2006-10-05 1 40
Abstract 2005-04-20 1 27
Description 2005-04-20 9 319
Claims 2005-04-20 4 107
Drawings 2005-04-20 8 131
Representative Drawing 2006-09-26 1 9
Assignment 2005-04-20 3 105