Note: Descriptions are shown in the official language in which they were submitted.
CA 02398684 2002-08-16
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CAM RATCHET SYSTEM WITH TENSION WHEEL
Field of the invention:
The present ratchet system has been developed to ease the installation of door
for
mini warehouses and commercial rolling steel doors, but may be applied to
other
types of installations where a torque must be applied on shaft and maintained.
Background of the invention:
All garage doors presently in use are counterbalanced by different means. Some
use a counterweight, others use a spring under traction or torsion. These
counterbalancing systems are required to lower the strength required by the
user
or the motorized system to raise and lower the door.
In the process to put the spring under tension, the installer must wind the
spring
and maintain this torque or tension in the spring by a different system.
Presently,
some systems are made with a U-bolt or a special bracket which is tightened
when
the spring is under tension. Some systems use a gear with an arm to act as a
ratchet. The present invention is in this last category, but requires a
minimum of
parts and reduces the overall system cost.
Summary of the invention;
The object of the present invention is to provide a "ratchet system", also
known as
a "winding system", which satisfies some of the above-mentioned needs and
which is thus an improvement over the ratchet systems known in the prior art.
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In accordance with the present invention, the above object is achieved, as
will be
easily understood, with a cam ratchet system provided with a tension wheel
such
as the one briefly described herein and such as the one exemplified in the
accompanying drawings.
The objects, advantages and other features of the present invention will
become
more apparent upon reading of the following non-restrictive description of
preferred embodiments thereof, given for the purpose of exemplification only
with
reference to the accompanying drawings.
Detailed description of preferred embodiments of the invention:
In the following description, the same numerical references refer to similar
elements. The embodiments shown in the enclosed figures are preferred.
Moreover, although the present invention was primarily designed for the
installation of door for mini ware house and commercial rolling steel door, it
may
be used with other objects and in other fields, as apparent to a person
skilled in
the art. For this reason, the expressions used herein should not be taken as
to
limit the scope of the present invention and includes all other kinds of doors
or
items with which the present invention may be useful.
Moreover, in the context of the present invention, the expressions "winding
system", "ratchet system", and any other equivalent expression known in the
art
will be used interchangeably. Furthermore, the same applies for any other
mutually equivalent expressions, as also apparent to a person skilled in the
art.
In addition, although the preferred embodiment of the present invention as
illustrated in the accompanying drawings comprises components and although the
preferred embodiment of the ratchet system as shown consists of certain
geometrical configurations as explained and illustrated herein, not all of
these
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components and geometries are essential to the invention and thus should not
be
taken in their restrictive sense, i.e. should not be taken as to limit the
scope of the
present invention. It is to be understood, as also apparent to a person
skilled in the
art, that other suitable components and cooperations thereinbetween, as well
as
other suitable geometrical configurations may be used for the cam ratchet
system
with tension wheel according to the present invention, as will be explained
hereinafter, without departing from the scope of the invention.
Broadly described, the present invention as shown in the accompanying drawings
relates to a cam ratchet system provided with a tension wheel.
Figures 1-6 present the cam ratchet system according to one aspect of the
invention, and may be described as follows:
A bracket 101 is joined to a wall bracket 102 by bolt and nut 103 or other
security
means. A special cam 104 which is attached to the bracket 101 and a bolt 105
are
also mounted on the bracket 101. A spring 106 links the cam 104 to the bracket
101 to complete the system and force the cam to move in one direction. To
facilitate the door location, the wall bracket 102 has a special slot 108
which
automatically locates the door at this correct position.
The cam 104 is eccentrically mounted so as to permit rotation of a shaft in a
first
rotation direction, but to prevent rotation in a second rotation direction.
In its normal use (see Figure 2), a shaft 110 which is attached to a spring by
coupling or other means, on which a rolling steel door 111 is pre-installed,
is
placed on wall bracket 102. The bracket 101 is then bolted 103 to the wall
bracket
102 around the shaft 110. The system is then completely operational. The
garage
door installer will then turn the shaft 112 with a pipe wrench or a special
tool and
the eccentric cam 103 will open and let the shaft turn freely (see Figure 3).
When
the installer stops turning the shaft (the shaft is now under tension created
by the
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torque spring on the garage door (not shown)), the torque 113 is maintained by
the
cam effect 114, in any position under tension (see Figure 4). When the
required
torque will be reached, bolt 105 is tightened to block any movement and ensure
the system safety. More specifically, Figure 3B shows the shaft being rotated
in a
clockwise direction. This rotation forces the cam to rotate in a counter
clockwise
direction. When the shaft, under no force to move in the clockwise direction,
and
by virtue of the tension (torque) present on the counterbalancing system,
attempts
to lower the torque by turning counter clockwise, the cam rotates clockwise by
an
amount sufficient that friction means, such as teeth as illustrated, engage
the shaft
and prevent further rotation.
Modification that may done to the invention but stay in the field of
application
-The cam 104 may be place in a way that gravity will act to replace the spring
106
effect.
-The counterbalancing spring may be direct to shaft but may also be installed
directly on the wall bracket as it is the case in commercial garage door and
residential garage door. In such case, some modifications have to be done, but
the
carn effect are still be possible to use.
Figures 7-10 present the cam ratchet system according to one aspect of the
invention, better illustrating the tension wheel thereof, and may be described
as
follows:
A tension wheel 1, which is installed to a wall bracket 2 by the neck shape in
its
centre 3. A special cam 4 which is attached to the bracket 1 by a shaft 5 also
mounted onto the bracket 1. A spring 6 relays the shaft 5 to the bracket 1
completes the system and preferably forces the cam to move in one direction.
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In its normal use, as better shown in Figure 8, a shaft 10 which is attached
to a
spring (not shown) by coupling or other means, on which a rolling steel door
is pre-
installed, is placed on wall bracket 2. The tension wheel 1 is then bolted or
welded
11 to the shaft 10. The system is then completely operational. The garage door
5 installer will then turn the shaft 10, (see Figure 9), with a bar 15 or
screw driver or
any tool that fits inside the tension wheel hole 12 and the eccentric cam 3
will
move away 13 and let the shaft turn freely. When the installer stops turning
the
shaft, this shaft is now under tension created by the torque spring on the
garage
door (not shown). Under this torque, the tension wheel is then maintained and
locked by the cam effect 14, as better shown in Figure 10, in any position
under
tension.
Modiftcation that may be done to the invention but stays in the field of the
application
-The cam 4 may be placed in a way that gravity will act to replace the spring
effect.
Although the present invention has been explained hereinabove by way of a
preferred embodiment thereof, it should be pointed out that any modifications
to
this preferred embodiment within the scope of the appended claims is not
deemed
to alter or change the nature and scope of the present invention.
