GB2301873A

GB2301873A - A Drive Mechanism, particularly for Roller or Under Roof Shutters.

Info

Publication number: GB2301873A
Application number: GB9612095A
Authority: GB
Inventors: John Anthony Edwards
Original assignee: J R IND Ltd
Current assignee: J R IND Ltd
Priority date: 1995-06-08
Filing date: 1996-06-10
Publication date: 1996-12-18
Also published as: GB9612095D0

Abstract

A drive mechanism comprises a belt drive 8 between a drive pulley 9 on a drive shaft and a driven pulley 10, automatic tensioning means acting as a clutch for tightening the belt into a drive condition when the drive shaft is driven, and biassing means 15 for causing the tensioning means to disengage when the drive to the drive shaft ceases. The tensioning means comprises an arm 23 carrying the drive shaft and pivotable about a main drive shaft 6. A spur gear 5 on shaft 6 rotates (either clockwise or anti-clockwise) to cause a driven spur gear 7 to pivot around the shaft 6 on arm 23 to tighten the belt 8 between the drive and driven pulleys. The driven pulley 10 then raises or lowers a roller shutter via a drive shaft 12 and driven sprockets 13. Details of shutter door locking, operating and lifting arrangements are described (see Figs 5-11).

Description

Improvements relating to Roller or Under Roof Shutter Designs The invention is concerned with means for transmitting powered motor drive and/or manual drive to a roller shutter or an under roof shutter. The design can be applied to shutters with rollers riding in tracks or to shutters with end shoes riding in tracks.

According to one aspect of the invention there is provided a shutter drive mechanism incorporating a belt drive from a pulley on a drive shaft to a pulley on a driven shaft for the shutter and automatic tensioning means acting as a clutch for tightening the belt into a drive condition when the drive shaft is driven, with biassing means for causing the tensioning means to disengage when the drive to the drive shaft ceases.

This design results in a number of advantages. On a powered motor driven shutter, the transmission allows the roller shutter to be manually over-ridden at any stage during operation. If the motor should fail in use, for example, this shutter can be manually operated as easily as if there were no power transmission system. The operator does not have to "back drive" either the gearbox or the motor.

The clutch is a particularly important feature of the design. Other designs would incorporate a centrifugal clutch on the drive side of the gearbox, where the torque is lower but which causes problems when an end user manually operates the shutter. To manually operate the shutter with a centrifugal clutch on the drive side of the gearbox, requires back driving through the gearbox, which is effort consuming. The final drive speed is too slow and the torque is too high to fit a centrifugal clutch on the driven side of the gearbox. Alternatively an expensive magnetic clutch could be fitted on the driven side of the gear box, but this is cost prohibitive. The proposed design adapts a simple automatic self-tensioning mechanism on the driven side of the gearbox, so it can function as a simple clutch.

Ideally the tensioning means comprises an arm carrying said drive shaft and drive pulley and pivotable about a main drive shaft, with a drive linkage between the main drive shaft and said drive shaft which will cause initial pivotal movement of said arm until the belt between the drive and driven pulleys is tightened. The drive linkage can comprise a driven spurgear which is secured on said drive shaft and engages with a drive spurgear fitted on the main drive shaft. Alternatively the drive linkage could comprise a driven spurgear linked to said drive shaft by a chain, and sprocket assembly and a drive spurgear fitted on the main drive shaft and engaging with the driven spurgear. The biassing means is preferably a spring acting on said arm.

A further aspect of the invention is a shutter door movable between open and closed positions and a shutter lock incorporating a microswitch which interfaces between a power source and a motor for driving the door, such that the microswitch is moved to the open condition when the shutter door is closed.

This assures that the motor cannot be switched on with the shutter door closed and locked. Mounting a lock and switch on a moving shutter door bottom rail itself would require a travelling cable. Consequently the preferred design features a lock and switch mounted on the door surround (that is off the shutter door). The lock can secure the door at both ends of the bottom rail. The locking system prevents the door from being opened either manually or under motor power (since operation of the lock opens the microswitch in the motor supply lead).

A further aspect of the invention comprises a shutter door locking arrangement comprising claw latches carried at the bottom of the door and striker pins on the base of the door surround to activate and link with the latches, a claw latch release bar connecting the latches and movable to release the latches from the striker pins, and an operating device for moving the release bar, the release bar and the operating device having engagement portions which link together when the door is in the closed condition and which move away from one another when the door is opened.

Yet another aspect of the invention, especially for an under roof shutter, relates to a cable/chain transmission arrangement suitable for either manual, motor power or dual mode operation. Other door designs balance the weight of the door and/or directly power-operate the door upwardly or downwardly by attaching cables to the exterior of the door.

One end of each cable is attached to the door and the other end of the cable is attached to a spring balance and/or a powered motor and transmission arrangement. Fitting cables like this has two disadvantages. The first is aesthetic.

Cables running down the outside of a door spoil the appearance of the end user's livery design. The second reason is functional. Because the cables are attached to the outside of the door (which, in end elevation is to one side of the vertical centre line of the door track), when a door lifting force is applied (either by the spring balance or by an end user), there is a tendency for that force to pull the door outwardly as well as upwardly. This adds friction to the operation of the door. On a door that is thick, like an insulated door, the friction is greater, because the distance from the centre of the door track to the cable is greater.

Conventionally a spring balance is positioned directly above the door, mounted on the inside of the header panel.

The cables wind onto a tube or cone. In so doing they traverse sidewardly as the door is raised and lowered.

Because of this it is not possible to position the cables at the edge of the door, hidden out of sight behind the door seals.

Also positioning the balancer above the door limits the height the door can be raised, because of the trajectory of the door panels and the confined space available for the balancer.

In another aspect of the invention a shutter operating system is provided wherein cables or chains are positioned on the inside of the door, one along each side edge, one end of the cable/chain assembly being attached to the edge of a bottom rail or panel, and the other end of the assembly passing over a pulley or pulleys mounted onto the inner side wall outside each track, to convert vertical lifting force into horizontal lifting force, the cable/chain being attached to an in-board mounted spring balancer and/or to a motor drive unit.

The cables can be mounted along each side edge of the door because they pass over pulleys before attachment to the spring balance assembly. So the cables along the inner door edge are unaffected by the traversing sideways movement as they wind onto the balancer tube or cone from the pulleys.

Not only do the cables lay adjacent to the inner door side edge but they are also positioned (in end elevation) a minimum distance from the centre of the track. During lift there are virtually no forces inducing friction, only forces inducing lift.

The sidewall mounted pulleys are ideally so positioned and are of sufficient diameter to allow the door to open right up and into the roof cavity, thereby giving maximum aperture height for cargo access. Preferably each pulley is covered by a removable shield. It is also preferred that a wheel larger than each pulley should be mounted adjacent thereto to act as a buffer for the trailing edge of the door as it is lifted to the fully raised position.

In manual only operation mode, the advantages are improved aesthetics from a hidden cable and less friction and therefore easier opening/closing. Also the door will lift right up and into the body of the vehicle, giving maximum cargo access. In power mode, instead of two cables, two roller chains can be attached to the door bottom edge, the other ends of the chains being attached to the door top.

The chain functions as a rack. The door can be driven upwardly and downwardly by a motorised sprocket assembly.

The motorised sprocket assembly functions as a pinion to produce a rack and pinion design. In a dual motor powered/manually driven door a cable is attached at some point to each chain, connecting them to the spring balancer. The door can then be either motor power driven or manually driven.

Yet another aspect of the invention comprises a shutter door end lifting arrangement wherein the lowermost roller of a series of rollers connected to the shutter door and mounted in a channel is linked to the shutter door by a pivot arm such that, when the shutter door is raised to its fullest extent, biassing means will cause the bottom end of the shutter door to rise about the pivot away from the lowermost roller as the lowermost roller is stopped or moves in a new trajectory. In the preferred arrangement the biassing means is a lifting cable/chain linked to the bottom of the shutter door and passing around a pulley/sprocket mounted above the top of the channel. The lifting cable or chain could comprise part of the shutter operating system of the invention as hereinbefore defined.

The invention may be performed in various ways and preferred embodiments thereof will now be described, by way of example, with reference to the accompanying drawings, in which:- Figure 1 is a section through a shutter drive mechanism of this invention; Figure 2 is an enlarged detail of a modified form of a pulley drive forming part of the construction of Figure 1; Figure 3 shows in greater detail and in side view parts of the pulley drive; Figure 4 illustrates the drive connection between the drive shaft of Figure 1 and a roller shutter; Figure 5 illustrates details of a cable drive connection of the invention to a roller shutter; Figure 6A is a more detailed illustration of a pulley of Figure 5; Figure 6B is an exploded view of the pulley of Figure 6A with other operating parts;; Figures 7 to 9 illustrate a shutter locking mechanism in different stages of operation; and Figures 10 and 11 show details of a modified form of shutter locking mechanism equivalent to that shown in Figures 7 to 9 of the original Application in side and plan view respectively.

Referring to Figures 1, 3 and 4, power is input from a motor 1 to a drive sprocket 2 and on to a torque limiter 3 via a drive chain 4. (The system will also work using pulleys with either a vee belt or a toothed belt). The torque limiter 3 is connected to a drive spurgear 5 via a drive shaft 6. As the drive spurgear 5 rotates (either clockwise or anti-clockwise) a driven spurgear 7 pivots around the drive shaft 6 on an arm 23 to tighten a vee belt 8. Once the vee belt 8 is tight enough, power is transmitted from a drive pulley 9 to a driven pulley 10. The driven pulley 10 raises or lowers a roller shutter 11 via a drive shaft 12 and driven sprockets 13. Teeth on the driven sprockets 13 mesh with end shoes 14 on shutter 11.

When power from motor 1 is switched off, a tension spring 15 pivots the driven spurgear 7 and pulley 9 back around the drive shaft 6 to loosen the vee belt 8 and thereby disengage the power transmission. In this non-motor drive mode a shaft collar 16 and belt guides 17 and 18 ensure that the natural geometry of the non-tensioned vee belt 8 is modified so that it is loose around the driven pulley 10 and that the vee belt 8 will not tighten around the driven pulley 10 when it is back-driven by the manual raising or lowering of the shutter 11. Manual operation of the shutter 11 is therefore uninhibited by restrictive friction between the vee belt 8 and the driven pulley 10.

A spring assisted balancer 19 aids both powered and manual operation. Since the spring balancer 19 tends to counterbalance the shutter 11, both manual effort and power operation are generally used to overcome friction only.

In the modified configuration of Figure 2 the size of the driven spurgear 7A is reduced. If a larger motor 1 is fitted, spurgears 5A and 7A will need to be made of steel and not plastics. A driven spurgear 7 of the size illustrated in Figure 1 in steel could be too heavy for the mechanism to work. The smaller driven spurgear 7A of Figure 2 is joined to a sprocket 20 which in turn is linked via a chain 21 to a sprocket 22. The difference in size between the sprockets 20 and 22 provide the necessary reduction in gearing. The sprocket 20 can be made from steel and, because of the large number of teeth on the sprocket 22 that engage with the chain 21, the sprocket 22 can be made from a light plastics or aluminium material.Another advantage of positioning driven spurgear 7A "behind" the drive spurgear SA is that the driven spurgear 7A helps to counterbalance the sprocket 22 and pulley 9 assembly.

In the arrangement of Figure 5 a cable 41 is attached to the bottom of a shutter door 47 by suitable means, as close in alignment with the centre of track 43 as is reasonably possible. The cable 41 passes around a pulley or sprocket 44 and is fastened with its free end to a spring balancer (not shown). The spring balancer balances the weight of the shutter door 47. A bottom roller 42 for the shutter door is mounted onto a pivot arm 40. The action of the pivot arm 40 and the position and radius of the pulley 44 are such that the shutter door 47 can open fully into the roof cavity, thereby giving maximum access for cargo during loading. This occurs as the roller 42 travels around the curved upper portion of the roller channel, but it could also be achieved by providing a stop for the roller 42 at the top end of the roller channel.

The design of the pulley 44 is shown in more detail in Figures 6A and 6B. The pulley is housed in a shield 24 which has apertures for the lead-in and lead-out of the cable 41. As can be seen from Figure 6B the shield 24 is loaded by a spring 25 so that it can be pulled back, when necessary, to allow the cable 41 to be laid in the groove of the pulley 44. As shown in Figure 6A the pulley 44 is held in place by a nut 26. Additionally a rubber tyred wheel 27 can be carried on the support shaft 28. A sleeve 28A, longer than the width of the pulley 44, is mounted about the sleeve 28, and provides support for the pulley 44, and ensures that the pressure of the spring 25 will not act upon the pulley. The wheel 27 is held in place by a circlip 27A.

The rubber tyred wheel 27 catches the trailing edge of the bottom panel 47 when it is raised to its fully open condition and so that the panel 47 does not interfere with the pulley 44.

Figures 7 to 9 illustrate features of a door locking mechanism. Power to a motor is routed through a lock 29 which has an integral micro switch. When the lock 29 is closed, the electrical power to the motor is off. When the lock 29 is open, the electrical power to the motor is on.

As a shutter 30 travels downwardly towards the fully closed position, a bottom rail bolt with an activating arm 31 engages and links with a shoot bolt 32. When the shutter 30 is fully down, the bottom rail bolt with the activating arm 31 is fully engaged or linked with the shoot bolt 32. As one moves side to side, upon operation of the lock 29, so the other moves side to side. The two members are linked together until the shutter is raised. The act of raising the shutter unlinks the aforesaid members.

When the shutter 30 is in the down position, and when the lock 29 is closed, the bottom rail bolt with the activating arm 31 also closes to engage a hole in the opposite track 33 thus securing that side of the shutter 30.

This same action of the lock 29 engages or links the shoot bolt 32 with a bottom rail locking dog 34, thereby securing the other end of the shutter 30. The shutter is unlocked by opening the lock 29 to effect the reverse action.

In the device of Figures 10 and 11, as a shutter door 51 travels downwardly toward the fully closed position, two bottom rail claw latches 52 and 53 engage and link with striker pins 54 and 55 to secure and lock the shutter door 51. This same action of closing the shutter door 51 also positions a claw latch release bar 56 so that it engages or is so located that a manual or power driven bracket 57 can activate the claw latches 52 and 53 via the release bar 56 and pivotally mounted operated arms 58. The claw latch release bar 56 and the bracket 57 remain in position or are linked together until the shutter is raised after the bracket 57 is moved by operating a lever 59 to release the latches. The act of raising the shutter unlinks or repositions the release bar 56 from the bracket 57.

Claims

1. A drive mechanism, such as for a shutter, incorporating a belt drive from a drive pulley on a drive shaft to a driven pulley on a driven shaft and automatic tensioning means acting as a clutch for tightening the belt into a drive condition when the drive shaft is driven, with biassing means for causing the tensioning means to disengage when the drive to the drive shaft ceases.

2. A drive mechanism according to Claim 1, wherein the tensioning means comprises an arm carrying said drive shaft and drive pulley and pivotable about a main drive shaft, with a drive linkage between the main drive shaft and said drive shaft which will cause initial pivotal movement of said arm until the belt between the drive and driven pulleys is tightened.

3. A drive mechanism according to Claim 2, wherein said drive linkage comprises a driven spurgear which is secured on said drive shaft and engages with a drive spurgear fitted on the main drive shaft.

4. A drive mechanism according to Claim 2, wherein said drive linkage comprises a driven spurgear linked to said drive shaft by a chain and sprocket assembly and a drive spurgear fitted on the main drive shaft and engaging with the driven spurgear.

5. A drive mechanism according to any one of Claims 2 to 4, wherein the biassing means comprises a spring acting on said arm.

6. A shutter door movable between open and closed positions and a shutter lock incorporating a microswitch which interfaces between a power source and a motor for driving the door, such that the microswitch is moved to the open condition when the shutter door is closed.

7. A shutter door according to Claim 6, wherein the lock and switch are mounted on the door surround.

8. A shutter door according to Claim 6 or Claim 7, wherein the lock secures the door at both ends of the bottom rail.

9. A shutter door locking arrangement comprising claw latches carried at the bottom of the door and striker pins on the base of the door surround to activate and link with the latches, a claw latch release bar connecting the latches and movable to release the latches from the striker pins, and an operating device for moving the release bar, the release bar and the operating device having engagement portions which link together when the door is in the closed condition and which move away from one another when the door is opened.

10. A shutter operating system wherein cables or chains for lifting the shutter door are positioned on the inside of the door, one along each side edge, one end of the cable/chain assembly being attached to the edge of a bottom rail/panel, and the other end of the assembly passing over a pulley or pulleys mounted onto a side wall of the assembly outside a curved top portion to each track, to convert vertical lifting force into horizontal lifting force, the cable/chain being attached to an in-board mounted spring balancer and/or to a motor drive unit.

11. A shutter operating system according to Claim 10, wherein the sidewall mounted pulleys are so positioned and are of sufficient diameter to allow the door to open right up and into the roof cavity, thereby giving maximum aperture height for cargo access.

12. A shutter operating system according to claim 10 or Claim 11, wherein each pulley is covered by a removable shield.

13. A shutter operating system according any one of Claims 10 to 12 wherein a wheel larger than each pulley is be mounted adjacent thereto to act as a buffer for the trailing edge of the door as it is lifted to the fully raised position.

14. A shutter operating system according to any one of Claims 10 to 13, wherein two roller chains are attached to the door bottom edge, the other ends of the chains being attached to the door top so that the chain functions as a rack, the door being driven upwardly and downwardly by a motorised sprocket assembly.

15. A shutter door end lifting arrangement wherein the lowermost roller of a series of rollers connected to the shutter door and mounted in a channel is linked to the shutter door by a pivot arm such that, when the shutter door is raised to its fullest extent, biassing means wl;l cause the bottom end of the shutter door to rise about the pivot away from the lowermost roller as the lowermost roller is stopped or moves in a new trajectory.

16. A lifting arrangement according to Claim 15, wherein the biassing means is a lifting cable/chain linked to the bottom of the shutter door and passing around a pulley/sprocket mounted above the top of the channel.

17. A lifting arrangement according to Claim 16, wherein the lifting cable or chain comprises part of the shutter operating mechanism according to any one of Claims 10 to 14.

18. A drive mechanism, substantially as herein described with reference to Figures 1 to 4 of the accompanying drawings.

19. A shutter door and lock assembly, substantially as herein described with reference to Figure 7 to 9 of the accompanying drawings.

20. A shutter door locking arrangement, substantially as herein described with reference to Figures 10 and 11 of the accompanying drawings.

21. A shutter door operating system, substantially as herein described with reference to Figures 5 and 6 of the accompanying drawings.

22. A shutter door end lifting arrangement, substantially as herein described with reference to Figure 5 of the accompanying drawings.

23. Any novel combination of features of a shutter door operating mechanism as described herein and/or as illustrated in the accompanying drawings.