U.S. patent application number 12/446855 was filed with the patent office on 2010-02-11 for flexible trap door.
Invention is credited to Ricardo Rodriguez Fernandez.
Application Number | 20100032240 12/446855 |
Document ID | / |
Family ID | 38330868 |
Filed Date | 2010-02-11 |
United States Patent
Application |
20100032240 |
Kind Code |
A1 |
Rodriguez Fernandez;
Ricardo |
February 11, 2010 |
FLEXIBLE TRAP DOOR
Abstract
Self-closing, flexible trap door for access platforms, enabling
its use as a work surface, consisting of a rubber body, fixed to
the access platform, strengthened by a cross-directional rigid
reinforcement, fitted with a tape to facilitate opening and a lock
when being transported and assembled. Closing is caused by the
pressure of the rubber. Additionally, the closing is caused by an
externally-driven mechanism or by means of magnets.
Inventors: |
Rodriguez Fernandez; Ricardo;
(Madrid, ES) |
Correspondence
Address: |
OSTROLENK FABER GERB & SOFFEN
1180 AVENUE OF THE AMERICAS
NEW YORK
NY
100368403
US
|
Family ID: |
38330868 |
Appl. No.: |
12/446855 |
Filed: |
September 26, 2007 |
PCT Filed: |
September 26, 2007 |
PCT NO: |
PCT/EP2007/008355 |
371 Date: |
June 26, 2009 |
Current U.S.
Class: |
182/222 |
Current CPC
Class: |
E04G 2001/155 20130101;
E04G 1/15 20130101 |
Class at
Publication: |
182/222 |
International
Class: |
E04G 5/00 20060101
E04G005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 11, 2006 |
ES |
P 200603128 |
Claims
1. Self-closing, flexible trap door for scaffolding access platform
that may be used as a work surface, consisting of a rubber body
fastened to the access platform, strengthened by a
cross-directional rigid reinforcement, fitted with a tape to
facilitate its opening and a lock while being transported and
assembled, the closing of which is caused by the pressure of the
rubber.
2. Flexible trap door according to claim 1, wherein the closing is
caused by an externally-driven mechanism.
3. Flexible trap door according to claim 1, wherein the closing is
caused by magnetic attraction.
Description
OBJECT OF THE INVENTION
[0001] The object of the present invention refers to a flexible
trap door for access platforms.
BACKGROUND OF THE INVENTION
[0002] One of the most important topics in present-day is to
guarantee the safety of workers. All social partners are making
efforts to reduce the number of accidents, above all in
construction, a sector where negative records are beaten.
[0003] With this in mind, improving scaffolding safety directly
helps to reduce the accident rate, since 70% of accidents are
caused by falls from different levels.
[0004] The EN-12810-1 2003 scaffolding Standard considers two ways
to pass from one level to another:
[0005] by means of a stepladder through an access platform
[0006] by means of an access stairway
[0007] The EN12811-1 Standard, in point 5.8.3, specifies:
[0008] "The free dimensions of the access opening on a platform
shall be at least 0.45 m in width, measured transversally across
the platform and 0.60 m in length. If it were not possible to close
the opening by means of a permanently attached trap door, a
protective guardrail must be able to be fitted. The trap door shall
be lockable in the closed position".
[0009] Two types of trap doors may be found on the market:
a) opening lengthwise along the platform (FIG. 1) b) opening
crosswise across the platform (FIG. 2)
[0010] In both cases, opening is manual and requires the use of at
least one hand while going up, thus reducing safety on going up the
stepladder.
Closing deserves separate treatment:
[0011] In case (a), a foreshortening is needed, since, while going
down in one direction, in the other, with the arm over the head,
the door must be held open. Moreover, and depending on the length
of the platform, the door hampers the following section of the
ladder.
[0012] In case (b), the opening position does not allow more than
90.degree., for which reason closing is caused by "gravity", which
leads to accidents on being a rigid, heavy element.
[0013] Workers on scaffolding normally carry tools in their hands,
and if it is necessary to go up a ladder of 40 m or more, opening
and closing doors, some to go upwards and others downwards, they
are considered to be always open.
[0014] In case (a), they are simply not closed, which makes the
situation worse, on the lower folding face of the trap door resting
on the upper part, which is the part trodden on.
[0015] In case (b), they either keep it forced open so it does not
close, causing broken hinges, or keep it fastened open with
wires.
Case (a) is curiously the most usual.
[0016] In both cases, the trap doors are normally made of two
materials: [0017] Plywood [0018] Aluminium plate
[0019] The load stipulated by the EN 12811-1 2003 Standard (point
6.2.4) corresponds to class 3, that is to say, 2.0 KN/m.sup.2.
DESCRIPTION OF THE INVENTION
[0020] The present invention refers to a flexible trap door
fastened to an access platform, that, when pushed by the worker's
helmet, opens by rolling up and stays open while passing through
the hole. Closing is "automatically" and progressively caused once
the worker has gone through. Once closed, it may be used as a work
surface, since it is strengthened by a cross-directional rigid
reinforcement, allowing it to support the working load.
[0021] To open it from above, it has a tape to half-open it and
place a foot on the first step of the ladder, opening it while
going down. When not in use, it has a lock to avoid its opening
while being transported and assembled.
[0022] This flexible trap may be used for access platforms in
general and more preferably for scaffolding access platforms.
[0023] The trap door consists of a flexible, lengthwise rubber
plate, cross-directionally reinforced inside, which enables it to
open and support the working load of 2.0 KN/m.sup.2 stipulated by
the EN 12811-1 2003 Standard. The materials that may be used are
very varied, but have to fulfil the following requirements:
Rubber
[0024] Resistance to environmental agents (UVA rays, temperature,
humidity . . . ) since scaffolding is generally used outdoors.
[0025] Non-slip upper surface, since it is to be used as a work
surface and walkway.
[0026] Variable flexibility, more flexible at the front and less
nearer its fastening point to the access platform, in order to
facilitate its opening and guarantee self-closing.
[0027] It shall resist chemical agents and show a certain
fire-resistance (flameproof) especially where the scaffolding is to
be used in industry.
[0028] 15 mm maximum thickness.
Reinforcement
[0029] They are profiles separated by a maximum of 4 cm.
[0030] They have to be as light as possible to facilitate opening
and not lead to an excessive weight being added to the access
platform unit.
[0031] It shall resist the working load of 2.0 KN/m.sup.2, with a
maximum flexion of 12 mm to guarantee the feeling of safety while
being trodden on.
Possible Rubbers:
[0032] Natural rubber with or without additives
[0033] Isoprene
[0034] Neoprene
[0035] Polybutadiene
[0036] Butyl rubber
[0037] Acrylic rubber
[0038] Polyethylene rubber
[0039] Silicon
[0040] Polysulphur
[0041] Vinyl ethylene-acetate
[0042] Fluorade . . . etc.
and its possible combinations
Possible Reinforcements:
[0043] Carbon fibre
[0044] Glass fibre
[0045] Aluminium
[0046] Copper
[0047] Brass
[0048] Steel
[0049] Wood
[0050] Combinations of different profiles and/or inter-connected,
forming a mesh or chain.
The shape of these profiles could be:
[0051] in round, square or rectangular pipe-shape
[0052] in T
[0053] in I
[0054] in triangle, etc.
Manufacturing Process:
[0055] Depending on the quantity, it may be continuously cast or
laminated, both in one direction as the other. The continuous
lamination must be with heat in the remoulding process, so that the
crosswise reinforcement sticks to the rubber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0056] FIG. 1: Trap door opening lengthwise along the platform.
[0057] FIG. 2: Trap door opening crosswise across the platform.
[0058] FIG. 3: Flexible trap door: rubber body (1), access platform
(2), rigid cross-directional reinforcement (3), tape (4) and lock
(5).
[0059] FIG. 4: Upwards sequence from one level to another.
[0060] FIG. 5: Downwards sequence from one level to another.
[0061] FIG. 6: Cross-directional reinforcement.
[0062] FIG. 7: Initial section of the flexible trap door according
to an embodiment method.
[0063] FIG. 8: End section of the flexible trap door according to
an embodiment method.
[0064] FIG. 9: Arrangement of the flexible trap door according to
an embodiment method.
DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
[0065] In a preferred embodiment of the invention, in the same way
as shown in FIG. 3, the flexible trap door is fastened to the
access platform (2) that opens by rolling up when pushed by the
worker's helmet and stays open while they pass through the hole.
Closing "automatically" and progressively takes place once the
worker has gone through. Once closed, it may be used as a work
surface, since it is strengthened by a cross-directional rigid
reinforcement (3), allowing it to support the working load.
[0066] To open it from above, it has a tape (4) to half-open it and
place a foot on the first step of the ladder, opening it while
going down.
[0067] When not in use, it has a lock (5) to avoid its opening
while being transported and assembled.
[0068] FIG. 6 shows a possible cross-directional reinforcement,
which would be made up of round aluminium pipes with an inner
diameter (D) of 5 mm, 1.5 mm (E1) thick and 1.5.times.2 mm
(E2.times.E3) flaps.
[0069] FIG. 7 shows an example of configuration that would be made
up of a silicon rubber body (1) with an inner polyester (6) mesh,
14 mm (E4) thick, with recesses of variable thickness (7) and
transversely strengthened by the reinforcement (3), separated by a
length (L) of 30 mm.
[0070] FIG. 8 shows the end section of the trap door, finishing off
in drill-holes (8) to fasten it to the access platform with a
diameter of 12 mm and a reinforcing flat bar (9).
[0071] FIG. 9 shows the arrangement of elements on a 650 mm-long
(H), 550 m-wide (A) trap door, displaying the typical profile of an
access platform (2).
* * * * *