AU2017203444B2

AU2017203444B2 - A brake system

Info

Publication number: AU2017203444B2
Application number: AU2017203444A
Authority: AU
Inventors: Stephen Rodney Jones
Original assignee: Monarch Group Pty Ltd
Current assignee: Monarch Group Pty Ltd
Priority date: 2016-06-07
Filing date: 2017-05-23
Publication date: 2022-03-17
Anticipated expiration: 2037-05-23
Also published as: AU2017203444A1

Abstract

A brake system for a panel lift door (1) having at least one counterweight (4, 5) connected via a cable (6, 7) to a traveller (22) which moves along a track (17) is disclosed. A spring (33) is compressed between the traveller (22) and an actuating member (32) urged by the cable (6, 7) to compress the spring (33). A roller (40, 140) is carried by the traveller (22) and is movable between a standby position in which the roller (40, 140) does not engage the track (17) and a brake applied positon in which the roller (40, 140) engages the track (17) and jams the traveller (22). A linkage (51) interconnects the roller (40, 140) and the actuating member (32), the linkage (51) being movable by the actuating member (32) to urge the roller (40, 140) into the brake applied position. Consequently, if the cable breaks, the spring (33) urges the actuating member (32) and linkage (51) to move the roller (40, 140) into the brake applied position. 3159E-AU 2 / 6 272/ \28 2 23 48 e22 "33- 44 4-5, 524 /-053 4k S56 FIG. 2 no

Description

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A BRAKE SYSTEM

Field of the Invention The present invention relates to panel lift doors such as those which find wide application in doors for garages, warehouses, and the like. Such doors may be manually operated or utilise a motor.

Background Art In order to reduce the load on either the user or the motor operating such doors, the door is provided with a counter weight, or more often a pair of counter weights, located one adjacent each side of the door. Particularly during opening of the door, the counter weights reduce the load on the user or motor. In particular, counter weight(s) enable a relatively small and inexpensive motor to open the door. Such doors have provided good service for many years.

However, particularly during the opening of such doors, there is a danger that if the cable connecting the counter weight with the door were to break, or a ferrule forming a connecting loop for the counter weight cable were to break, then the weight of the now no longer counter balanced door maybe sufficient to overcome the force of the motor, or the ability of the user to control the door, and the door may close unintentionally.

Such an unintended closing of the door represents a potential safety hazard and it would therefore be desirable to ensure that such a hazard does not arise.

Genesis of the Invention The genesis of the present invention is a desire to provide a brake for such doors which does not operate during normal operation of the door, but in the event of a failure of one or more counter weights, then the brake will come into operation.

Summary of the Invention According to an aspect of the present invention there is provided a brake system for a panel lift door having at least one counterweight connected via a cable to a traveller which moves along a track, said system comprising a spring compressed between said

'21CZOU ATT traveller and an actuating member urged by said cable to compress said spring, a roller carried by said traveller and movable between a standby position in which said roller does not engage said track and a brake applied positon in which said roller engages said track and jams said traveller, and a linkage interconnecting said roller and said actuating member, said linkage being movable by said actuating member to urge said roller into said brake applied position, whereby if said cable breaks, said spring urges said actuating member and linkage to move said roller into said brake applied position.

According to a second aspect of the present invention there is also disclosed a method of braking a door having at least one counterweight connected via a cable to a traveller which moves along a track, said method comprising the steps of: locating a compression spring between said traveller and an actuating member to urge said cable to compress said spring, positioning a roller carried by the traveller to be movable between a standby position in which the roller does not engage the track, and a brake applied position in which the roller engages the track and jams the traveller, and interconnecting the roller and the actuating member by a linkage which is movable by the actuating member to urge the roller into the brake applied position, whereby if said cable breaks, said spring urges said actuating member and linkage to move the roller into the brake applied position.

Brief Description of the Drawings A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a schematic perspective view showing a panel lift door with a single motor and two counter weights; Fig. 2 is a partially cut away, exploded perspective view of the brake of a first embodiment illustrated within the channel within which it is housed; Fig. 3A is a side elevation of the brake of Fig. 2 showing the normal standby operation of the brake; Fig. 3B is a view similar to Fig. 3A but showing the initial movement of the brake following a rupture in the cable supporting the counter weight; Fig. 3C is a view similar to Fig. 3B but showing the brake fully applied; and

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Fig. 4 is a partial exploded perspective view showing the roller arrangement of a brake of a second embodiment in its standby position.

Detailed Description As seen in Fig. 1, a panel lift door1 is supported between two columns 2, 3. Travelling alongside, or within, each column is a corresponding counter weight 4, 5. Each of the counter weights 4, 5 is connected to the door 1 by means of a corresponding cable 6, 7 which passes over the top of a corresponding pulley 9, 10. Each of the pulleys 9, 10 is mounted at the top of its corresponding column 2, 3.

A small and relatively inexpensive motor 12 drives the door 1 through a known mechanism. In known fashion, the movement of the door 1 is guided by means of two tracks 14, 15 so as to guide the door between the fully open and fully closed positions. In Fig. 1 the door1 is illustrated intermediate these positions.

It will be apparent to those skilled in the art that should one of the cables 6, 7 break, or the cable become detached from the door opening mechanism, or the cable become detached from the corresponding counter weight 4, 5, then the sudden increase in the apparent weigh of the door 1 can be sufficient to overcome the force of the motor 12 and cause the door 1 to drop. This represents a potential safety hazard.

Turning now to Fig. 2, a first embodiment of a pair of brakes which overcomes the safety hazard is illustrated. Each brake is locating within a channel 17 having a base 18 and two side walls 19, 20. Each of the columns 2, 3 has a corresponding channel 17. Positioned within the channel 17 is a traveller 22 which has a stub axle 23. The stub axle 23 passes through a thimble 24 which has an exterior groove 25 around which the cable 6, 7 is secured by means of a ferrule 27. The thimble 24 has an interior opening 28 which is larger in size than the cross-sectional area of the stub axle 23.

Extending from the thimble 24 is a Z-shaped member 32 which compresses a compression spring 33 which is trapped in a cavity 34. The effect of the compression spring 33 is to apply a downwardly directed force on the thimble 24. However, gravity acting on the corresponding counter weight via the cable 6, 7 applies an

'21CZOU ATT upwardly directed force to the thimble 24 which is greater than the downwardly directed force created by the compression spring 33. As a consequence, under normal conditions, the thimble 24 applies a net upwardly directed force to the stub axle 23 and hence to the traveller 22. This upwardly directed force is the effective weight of the counter weight.

As seen in Fig. 2, the traveller 22 includes a roller 40 having a knurled exterior surface 41. The roller 40 has a central axle 43 which travels in two inclined slots 45, 46. The inclined slot 45 is in the body of the traveller 22 and the inclined slot 46 is in a face plate 48 which is secured to the traveller 22 by means of fasteners 49.

The roller 40 is connected to the Z-shaped member 32 by means of a linkage 51 which has an elongate member 52 which has an elongate slot 53 which receives a pin 54 extending from the Z-shaped member 32. A further pin 56 extends through the elongate member 52.

Turning now to Fig. 3A, during normal operation the brake is in its standby position, and the thimble 24 exerts an upward force on the stub axle 23 of the traveller 22. So the stub axle 23 remains positioned at the lower end of the interior opening 28 of the thimble 24. In this position the Z-shaped member 32 compresses the compression spring 33 and the linkage 51 is un-activated. Thus the roller 40 lies in the position illustrated in Fig. 3A with its central axis 43 lying at the lower end of the inclined slots 45, 46. In this configuration the traveller 22 is free to move within the channel 17 under the influence of the motor 12, and clears the opposite side walls 19, 20 of the channel17.

Turning now to Fig. 3B, the situation is illustrated in which the cable 6, 7 happens to rupture, in which case the cable no longer applies an upwardly directed force to the thimble 24. As a consequence, the spring 33 is no longer fully compressed and extends downwardly. This moves the Z-shaped member 32 in a downward direction thereby simultaneously drawing the thimble 24 downwardly relative to the stub axle 23 and at the same time moving the linkage 51 so as to drive the roller 40 upwardly.

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As seen in Fig. 3C, the upward motion of the roller 40 engages the roller 40 with the side wall 19, thereby pushing the traveller 22 to the right as seen in Fig. 3C. This jams the traveller 22 against the side wall 20 of the channel 17 and thereby applies the brake to the door 1.

As a consequence of this braking action, although the counter weight with the ruptured cable has fallen downwardly, the traveller 22 (which is connected with the door 1), has its motion braked. Thus the door 1 comes to a stop, notwithstanding the failure of the counter weight mechanism. As a result, safe operation of the door 1 is guaranteed notwithstanding rupture of the cable 6, 7 or the coming loose, for example, of the ferrule 27.

A second embodiment is illustrated in Fig. 4, in which the roller 40 of Figs. 2 and 3 is modified to create a roller 140 having a central groove 158 against which the elongate member 52 of the linkage 51 acts. Thus in the second embodiment illustrated in Fig. 4, the interconnection between the linkage 51 and the roller 140 ensures a more even and symmetrical movement of the roller 140.

The foregoing describes only two embodiments of the present invention and modifications, obvious to those skilled in the panel door arts, can be made thereto without departing from the scope of the present invention. For example, although the described embodiments relate to a motorised panel door, the invention is equally applicable to doors without a motor.

The term "comprising" (and its grammatical variations) as used herein is used in the inclusive sense of "including" or "having" and not in the exclusive sense of "consisting only of'.

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Claims

CLAIMS 1. A brake system for a panel lift door having at least one counterweight connected via a cable to a traveller which moves along a track, said system comprising a spring compressed between said traveller and an actuating member urged by said cable to compress said spring, a roller carried by said traveller and movable between a standby position in which said roller does not engage said track and a brake applied positon in which said roller engages said track and jams said traveller, and a linkage interconnecting said roller and said actuating member, said linkage being movable by said actuating member to urge said roller into said brake applied position, whereby if said cable breaks, said spring urges said actuating member and linkage to move said roller into said brake applied position.
2. The brake system as claimed in claim 1 wherein said roller has a roller axle and said linkage bears on said roller axle.
3. The brake system as claimed in claim 2 wherein said traveller includes a pair of slots each inclined to said track, and said roller axle extends between said slots and is movable along said slots by said linkage.
4. The brake system as claimed in any one of claims 1-3 wherein said track comprises a U-shaped channel having a base located between a pair of side walls, and said roller bears against one of said side walls and urges said traveller to bear against the other one of said sidewalls.
5. The brake system as claimed in any one of claims 1-4 wherein said roller has a substantially centrally located groove which divides said roller in two, and said linkage engages with, and bears against said groove.
6. The brake system as claimed in any one of claims 1-5 wherein said traveller has a stub axle, said actuator includes a thimble having an interior opening through which said stub axle passes, the size of said opening being greater than the cross sectional area of said stub axle, and said cable is looped around said thimble, said cable urging said thimble in a first direction, and said compressed spring urging said

3159E-AU cable in a second direction, opposite to said first direction.
7. The brake system as claimed in claim 6 wherein said thimble has an exterior groove sized to receive said cable.
8. The brake system as claimed in any one of claims 1-7 wherein said door is motorised.
9. The brake system as claimed in any one of claims 1-7 wherein said door is manually operated.
10. A method of braking a door having at least one counterweight connected via a cable to a traveller which moves along a track, said method comprising the steps of: locating a compression spring between said traveller and an actuating member to urge said cable to compress said spring, positioning a roller carried by the traveller to be movable between a standby position in which the roller does not engage the track, and a brake applied position in which the roller engages the track and jams the traveller, and interconnecting the roller and the actuating member by a linkage which is movable by the actuating member to urge the roller into the brake applied position, whereby if said cable breaks, said spring urges said actuating member and linkage to move the roller into the brake applied position.

Dated this 23th day of May 2017

MONARCH GROUP PTY LIMITED

By FRASER OLD & SOHN Patent Attorneys for the Applicant

3159E-AU

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