CA2398684A1

CA2398684A1 - Cam ratchet system with tension wheel

Info

Publication number: CA2398684A1
Application number: CA002398684A
Authority: CA
Inventors: Normand Savard; Michel Beaudoin
Original assignee: Canimex Inc
Current assignee: Canimex Inc
Priority date: 2002-08-16
Filing date: 2002-08-16
Publication date: 2004-02-16

Description

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.

2 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

3 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

4 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 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.

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.