WO1991005729A2

WO1991005729A2 - Improvements in or relating to self-winding reel assemblies

Info

Publication number: WO1991005729A2
Application number: PCT/GB1990/001558
Authority: WO
Inventors: Ian James Prismall
Original assignee: Pivot Engineering Limited
Priority date: 1989-10-11
Filing date: 1990-10-10
Publication date: 1991-05-02
Also published as: GB2237005B; GB9021978D0; GB2237005A; AU6536690A; GB8922937D0; WO1991005729A3; EP0495870A1

Abstract

A self-winding reel assembly comprises a spool (18) rotatably mounted, within a housing (10), around a fixed shaft (17). A flexible belt (32) wound around the spool is provided on its free end with a catch device (34) for connection to a retainer when the belt is unwound from the spool to form a temporary barrier. The spool (18) is driven by a clock spring (25) which is located in a space (24) within the spool (18) itself. An adjustable cam device (29) rotates with the spool to operate a micro switch (30) controlling an electric alarm device (31). Rotation of the spool (18) may be controlled by an air brake or inertia brake.

Description

"Improvements in or relating to self-winding reel assemblies"

The invention relates to self-winding reel assemblies of the kind comprising a spool rotatably mounted on a fixed support member, the spool having means for attaching thereto one end of a flexible elongate element to be wound around the periphery of the spool, and the support member being shaped to allow the passage of the flexible element as it is wound onto and off the spool. A driving device is connected between the spool and the fixed support member to rotate the spool to wind the flexible element back on to the spool after it has been withdrawn. Such device usually comprises a spring so connected that it is loaded by rotation of the spool in one sense relatively to the fixed support member, so that the spring, when the spool is released, rotates the spool in the opposite sense.

Such reel assemblies are used in many different applications. For example, the assembly may be used in a retractable barrier device of the kind described in our co-pending British Patent Application No. 8916422-2. However such reel assemblies are capable of many other applications such as in self-retracting seat belts for motor vehicles and in any other situation where self-winding of a flexible elongate element on to a spool is required.

Throughout this specification the term "spool" is intended to include any shape of element which is capable of being rotated to wind on to it a flexible elongate element. Thus, it includes conventional spools comprising a central cylindrical spindle provided with circular end flanges between which the flexible element is wound, but it is not limited to such devices.

In conventional reel assemblies of the kind first referred to, the spring is normally located at one end of the spool and one such arrangement is shown in the above-mentioned British Patent Application No. 8916422-2. However, this arrangement means that the axial length of the whole assembly is significantly greater than is required to accommodate the spool itself, and this may result in an assembly which is unacceptably lengthy for some applications. The present invention sets out to provide a construction whereby the axial length of the reel assembly may be reduced.

According to the invention there is provided a self-winding reel assembly comprising a spool rotatably mounted on a fixed support member, the spool having means for attaching thereto one end of a flexible elongate element to be wound around the periphery of the spool, and the support member being shaped to allow the passage of the flexible element as it is wound on to and off the spool, there being provided within the spool an internal space within which is located a driving device which is connected between the spool and the fixed support so as to effect rotation of the spool relatively to the fixed support, when required, and thereby rewind the flexible element on the spool.

Preferably the driving device comprises a spring.

Since, in the arrangement according to the invention, the spring or other driving device is located within the spool itself, rather than at one end thereof, the axial length of the spool is determined solely by the required axial length necessary to accommodate the flexible elongate element, and is therefore kept to a minimum. In order to accommodate the driving device within the spool, some increase in its diameter may be required, although this is not essential, but usually a slight increase in diameter is preferable to an excessive length. In the case where the driving device comprises a spring it may be a spiral spring wound around the central longitudinal axis of the spool, one end of the spring being connected to the interior of the spool and the other end being connected to a part of the support member. The part of the support member to which said other end of the spiral spring is connected may comprise a fixed central shaft around which the spool is rotatable.

The spool may include a generally tubular sleeve and two spaced end caps closing the ends of the sleeve, said driving device being located in the space within the sleeve and between said end caps. Said end caps may be provided respectively with circular end flanges coaxial with the tubular sleeve and extending radially outwardly thereof.

Alternatively, the spool may include a generally cylindrical main body part integrally formed at one end with a cavity within which said driving device is at least partly located. There may be provided a closure member closing said cavity, means being provided securing the closure member to said main body part. Said closure member and main body part may be provided respectively with circular end flanges coaxial with the main body part and extending radially outwardly thereof.

In any of the above arrangements the reel assembly may include an electric switch for operating an electric alarm device, there being provided a cam device rotatable with the spool and adapted to operate the electric switch as the spool rotates through one rotational position thereof. Preferably the cam device is rotationally adjustable with respect to the spool whereby the rotational position of the spool when the switch is operated may be variable. For example, the cam device may include a sleeve which encircles and frictionally engages a cylindrical element which is rotatable with the spool, whereby the rotational position of the cam device with respect to the spool may be varied by relative rotation between the spool and cam device, against the action of said frictional engagement. The reel assembly may include a braking device coupled to said spool to brake rotation thereof. The braking device may comprise an air brake element or a flywheel rotatable with the spool, and may be mounted on a rotatable shaft separate from said spool, a drive mechanism being connected between the spool and said shaft so that the shaft rotates with the spool. A free¬ wheel device may be provided between the spool and the braking device, enabling the spool to rotate independently of the braking device in one direction.

In any of the arrangements according to the invention the free end of the flexible element may have secured thereto a catch device which magnetically engages a retainer device which, in use, is located in a position spaced from the reel assembly.

Alternatively, there may be provided a catch device which snaps into mechanical interlocking engagement with a cooperatively shaped retainer device. The catch device may include at least one snap unit comprising two spaced resilient arms adapted to enter a cavity in the retainer device, the arms being formed respectively with outward projections which snap past corresponding inward projections at the mouth of the cavity, as the snap unit enters the cavity, the inter- engagement between said projections tending to retain the snap unit in the cavity. The projections on the arms of the snap unit and the walls of the cavity in the retainer device may be cooperatively shaped so as to squeeze said arms together as the snap unit is pushed into the cavity, the width of the arms being sufficient to permit one side thereof then to withdrawn from the cavity, by sideways tilting of the snap unit, while the other sides of the arms remain in engagement with the walls of the cavity, squeezing said arms together.

The following is a more detailed description of embodiments of the invention, by way of example, reference being made to the accompanying drawings in which:

Figure 1 is a longitudinal section through one form of reel assembly according to the present invention.

Figure 2 is a plan view of the assembly of Figure 1,

Figure 3 is an enlarged sectional view through the cam device of the assembly for operating an alarm.

Figures 4 and 5 are similar views to Figures 1 and 2 of an alternative form of reel assembly, Figure 6 is a longitudinal section through a further form of reel assembly.

Figure 7 is a vertical section through a catch device and retainer for use with a reel assembly, and

Figure 8 is a horizontal section through the catch device and retainer on Figure 7.

Referring to Figures 1 and 2: the reel assembly comprises a housing 10 bent from sheet metal and comprising a top wall 11, a bottom wall 12 and a rear wall 13. An angled vertical wall member 14 fits within the front of the housing 10 to provide a cavity 15 and a peripheral flange 16 surrounds the rectangular mouth of the cavity 15. A fixed vertical shaft 17 extends between the upper and lower walls 11, 12 of the housing and is secured to said walls respectively, so as to be non- rotatable. Rotatable around the fixed shaft 17 is a spool 18. The spool comprises a central tubular portion 19. Secured within opposite ends of the tubular portion 19 are solid cylindrical end portions 20 and 21 formed with enlarged circular end flanges 22, 23 respectively.

The axial lengths of the end portions 20, 21 are such as to define between their inner ends an annular space 24 within which is located a spiral clock spring 25. The inner end of the clock spring is secured to the shaft 17 and the outer end is secured to the interior of the central tubular portion 19 of the spool.

A bearing collar 26 encircles the shaft 17 above the upper flange 22 and serves as a thrust bearing. Secured to the lower flange 23 is a sleeve 27 integrally formed at its lower end with a circular flange 28 which rests on the upper surface of the wall 12. Encircling the sleeve 27 between the flanges 23 and 28 is a part-circular cam device 29 which cooperates with a micro switch 30 mounted on the lower wall 12 and serves to actuate an electronic alarm device 31, as will be described later, the alarm device 31 being mounted on the rear wall 13 of the housing 10.

The end closures 20, 21, flanges 22, 23 and collars 26, 27 may be formed from any suitable material. For example they may be formed from metal or plastics or from any combination thereof. The components may be integrally formed or may be separately formed and secured together by welding or adhesive depending on the nature of the materials.

Secured to the outer surface of the tubular portion 19 of the spool is one end of a flexible flat belt 32 of webbing or the like. The belt is wound around the tubular portion 19 between the flanges 22, 23, passes through a vertical elongate slot 33 in the angled wall unit 14, and is secured to a catch device 34. The catch device 34, which may be a magnetic device as described, for example, in our British Patent Specification No. 2221797, is adapted for releasable connection to a fixed retainer (not shown) located at a distance from the reel assembly. In use, the assembly shown in Figures 1 and 2 may be mounted within a suitable space in a vertical wall or cabinet, for example a cabinet unit defining one side of a supermarket exit passage. The flange 16 surrounds the mouth of the aperture into the wall or cabinet so that all that can be seen of the assembly is the interior of the cavity 15 and the catch device 34. On the other side of the passageway, and opposite the reel assembly, the aforementioned retainer is secured to an opposite cabinet or wall.

Initially, when the catch device 34 lies within the cavity 15, the belt 32 is entirely wound upon the spool 18 and the clock spring 25 is unloaded or is only slightly loaded. When it is wished to extend the belt across the passageway to prevent access, the catch device 34 is withdrawn from the cavity 15 and pulled across the passageway and engaged with the opposite retainer. This withdraws the belt 32 from the reel assembly causing the spool 18 to rotate relatively to the fixed shaft 17 and the spiral spring 25 to become wound up and tensioned. When, subsequently, the catch device 34 is detached from the retainer, the loading of the spring 25 causes the spool 18 to rotate in the opposite direction so as automatically to rewind the belt 32, or part thereof, back on to the spool.

It will be seen that since the spring 25 is located internally of the spool 18, the overall axial length (i.e. vertical height) of the assembly can be less than would be necessary if the spring were located at one end of the spool, as has usually been the case hitherto.

Although the described assembly is particularly suitable for use with a flat belt, it may equally well be used with elements of other sections, such as cords or chains.

The assembly may be used in any orientation, for example with the axis of the shaft 17 horizontal or at an angle to the horizontal.

Although a spiral clock spring is particularly suitable as the driving device for enclosure within the spool, other forms of spring may be employed. Also, other types of driving device may be employed. For example the driving device may comprise an electric motor within the spool. The outer casing of the motor may form all or part of the spool, the shaft of the motor being connected to the fixed casing or other support so that the motor casing rotates as the motor is energised.

The alarm unit 31 controlled by the cam device 29 and micro switch 30 is arranged to be operated by release or movement of the belt 32 after the belt has been extended across the passageway and the catch device 34 engaged with the fixed retainer.

The cam device 29 and micro switch 30 are shown in greater detail in Figure 3. The cam device 29 is in the form of a part-circular sleeve formed with a semicircular axial enlargement 35 opposite the gap 36 in the periphery of the sleeve. The cam device 29 is formed from plastics and is in sprung frictional engagement with the aforementioned sleeve 27 which rotates with the spool 18 about the fixed shaft 17. It is desirable that, when the belt 32 is fully extended and the catch device 34 is in engagement with the fixed retainer, the enlargement 35 on the cam device 29 is spaced approximately 90° from the micro switch 30 as shown in Figure 3. Upon unauthorised release of the belt the spool, and hence the sleeve 27 and cam device 29, rotate clockwise as viewed in Figure 3, under the action of the spring 25, to rewind the belt 32 on to the spool 18. However, after the spool has rotated clockwise through 90" the enlargement 35 operates the micro switch 30 and energises the alarm 31 which may be an audible and/or visual alarm. An authorised person will have de-activated the alarm before releasing the belt so that energisation of the alarm will indicate that unauthorised release of the belt has taken place.

If the belt is interfered with without actually releasing the catch device 34 from the retainer, a further short length of the belt will normally be pulled from the spool causing the spool to rotate anti-clockwise as viewed in Figure 3. When the spool has rotated anti-clockwise through 270", the enlargement 35 will operate the micro switch 30 and thus again energise the alarm. This greater necessary distance of rotation of the spool ensures that the alarm is unlikely to be operated accidentally by slight pressure on the extended belt causing only very slight further withdrawal of belt from the spool. It will be appreciated that the extent of withdrawal of the belt from the spool, and hence the extent of rotation of the spool, when the catch device is engaged with the retainer will vary according to the width of the passageway across which the belt is to extend. The cam device 29 is therefore adjustable on the sleeve 27 so that it may be positioned in the appropriate rotational relationship to the micro switch 30 whatever length of belt is withdrawn. To facilitate this adjustment of the cam device the bottom wall 12 of the housing is formed with a hole 37 which is located diametrically opposite the required position for the enlargement 35 of the cam device. To set the cam device, it is initially positioned with the gap 36 in register with the hole 37 when the belt 32 is completely rewound on to the spool 18 and the catch device 34 is lying within the cavity 15 in the housing 10. A small rod 38 is then pushed up through the hole 37 so as to lie within the gap 36. The belt is then withdrawn from the assembly and extended across the passageway until the catch device 34 engages the fixed retainer. During this movement the rod 38 prevents the cam device 29 from rotating and the sleeve 27 on the spool therefore rotates relatively to the cam device 29 against the action of the frictional engagement between the two. Once the catch device 34 has been engaged with the fixed retainer the rod 38 is withdrawn so that in all further operations of the assembly the cam device 29 rotates with the sleeve 27 and hence with the spool 18. Each time the belt is extended the cam device 29 will be brought to the desired position shown in Figure 3 so it is correctly spaced from the micro switch 30. The clock spring 25 must be sufficiently powerful to provide complete and reliable rewinding of the belt on the spool, but it may be desirable to slow down the rewinding action to prevent the possibility of injury to the operator, or damage to the surrounding fittings, as the catch member 34 is snapped back into its housing. Figures 4 to 6 show suitable braking arrangements.

In the arrangement of Figures 4 and 5, an air brake is provided comprising fan blades 39 mounted on a rotatable shaft 40 spaced from the shaft 17 and parallel thereto. The shaft 40 is driven by a belt drive 41 encircling pulley wheels 42 and 43 on the flange 23 and shaft 40 respectively. Instead of the air brake illustrated, a suitable inertia brake may be provided by mounting a fly-wheel on the shaft 40.

In the alternative arrangement shown in Figure 6 a shaft 44 spaced from and parallel to the shaft 17 is driven by gearing 45 in meshing engagement with gear teeth on the upper flange 55 of the spool. In this case the blades 46 of an air brake are mounted at the lower end of the shaft 44 and in this case also the air brake could be replaced by a flywheel. In the arrangement of Figure 6 the drive between the spool and the air brake 46 incorporates a free wheel mechanism in the form of a dog-clutch 47 controlled by a spring 48. When the belt 32 is being withdrawn from the spool, the spool is rotated anti¬ clockwise and the shaft 44 rotates clockwise so that the clutch 47 disengages and the withdrawal of the belt from the spool is not opposed by the air brake or inertia brake. On the other hand, when the belt is subsequently released and is being rewound on the spool the spool rotates clockwise and the shaft 44 rotates anti¬ clockwise so that the clutch 47 is engaged and the air brake or inertia brake slows down the rotation. Figure 6 also illustrates an alternative form of construction of the spool 18. In this case the spool comprises a cylindrical main body 49 which may be moulded from plastics material and integrally formed at its lower end with the flange 50 and sleeve 51. The main body 49 is provided at its upper end with a cylindrical cavity 52 which receives the spiral clock spring 53. The cavity 52 is closed by an end closure member 54 which is integrally formed with the upper flange 55 and is designed to be a snap-fit into the upper periphery of the walls on the main body 49 defining the cavity 52.

As previously mentioned, a preferred form of catch device and retainer for use with the reel assembly is of the magnetic kind described in our earlier British Patent Specification No. 2221797. However, other forms of catch device and retainer are possible, and Figures 7 and 8 illustrate a new mechanical type of device.

Referring to Figure 8: the catch device 56 is engageable with a fixed retainer 57. As best seen in Figure 7, there is mounted in the catch device 56 a block 58 moulded from plastics material and integrally formed with four vertically spaced snap units 59. Each snap unit comprises two vertically spaced arms 60 formed along their free edges with outward projections 61. Each snap unit 59 can enter a corresponding cavity 62 formed in the retainer 57. The mouth of each cavity is bordered by upper and lower inward projections 63 so that as each snap unit 59 enters the associated cavity 62 the projections 61 on the arms 60 snap past the projections 63, as a result of the resilience of the arms 60, and engage behind them thus retaining the snap units 59 in the cavities 62. By this means the catch device 56 is held on the retainer 57.

It will be seen from Figure 7 that the upper and lower walls 64 of each cavity 62 are inclined and the end edges of the arms 60 are similarly inclined for mating engagement therewith. Consequently, if the block 58, after the snap units 59 have been engaged, is pushed further towards the retainer 57 the engaging inclined surfaces have the effect of squeezing the arms 60 of each snap unit towards one another.

As may be seen from Figure 8, the arms 60 of each snap unit are comparatively wide and extend for the whole width of the block 58. If the catch device 56 is tilted sideways, therefore, one side of each snap unit will be forced further into the retainer 57 causing the arms of the snap unit to be squeezed together. At the same time the opposite side of each snap unit will tend to move away from the retainer 57, and since the arms of each snap unit have been squeezed together, the projections 61 will have been moved inwardly clear of the projections 63 at the mouths of the cavities so that the opposite side of each tilted snap unit may pass out of its associated cavity. The snap units can then be completely withdrawn from the retainer 57 either by continuing to tilt the catch device sideways or by pulling it away from the retainer 57 while it is still tilted.

In all of the arrangements described and illustrated above the driving device for the reel assembly is a spiral clock spring located within the spool. However, it will be appreciated that certain of the other features described, such as the cam operated alarm device, the air or inertia brake, or the mechanical catch/retainer device of Figures 7 and 8, may also be used with other, conventional forms of reel assembly including those where the driving device for the spool is located at one end of the spool instead of being located within it.

Claims

CLAIMS 1. A self-winding reel assembly comprising a spool rotatably mounted on a fixed support member, the spool having means for attaching thereto one end of a flexible elongate element to be wound around the periphery of the spool, and the support member being shaped to allow the passage of the flexible element as it is wound on to and off the spool, there being provided within the spool an internal space within which is located a driving device which is connected between the spool and the fixed support so as to effect rotation of the spool relatively to the fixed support, when required, and thereby rewind the flexible element on the spool.

2. A reel assembly according to Claim 1, wherein the driving device is a spring.

3. A reel assembly according to Claim 2, wherein the spring is a spiral spring wound around the central longitudinal axis of the spool, one end of the spring being connected to the interior of the spool and the other end being connected to a part of the support member.

4. A reel assembly according to Claim 3, wherein the part of the support member to which said other end of the spiral spring is connected comprises a fixed central shaft around which the spool is rotatable.

5. A reel assembly according to any of Claims 1 to 4, wherein the spool includes a generally tubular sleeve and two spaced end caps closing the ends of the sleeve, said driving device being located in the space within the sleeve and between said end caps.

6. A reel assembly according to Claim 5, wherein said end caps are provided respectively with circular end flanges coaxial with the tubular sleeve and extending radially outwardly thereof.

7. A reel assembly according to any of Claims 1 to 4, wherein the spool includes a generally cylindrical main body part integrally formed at one end with a cavity within which said driving device is at least partly located.

8. A reel assembly according to Claim 7, and further comprising a closure member closing said cavity, means being provided securing the closure member to said main body part.

9. A reel assembly according to Claim 8, wherein said closure member and main body part are provided respectively with circular end flanges coaxial with the main body part and extending radially outwardly thereof.

10. A reel assembly according to any of Claims 1 to 9, including an electric switch for operating an electric alarm device, and a cam device rotatable with the spool and adapted to operate the electric switch as the spool rotates through one rotational position thereof.

11. A reel assembly according to Claim 10, wherein the cam device is rotationally adjustable with respect to the spool whereby the rotational position of the spool when the switch is operated may be variable.

12. A reel assembly according to Claim 11, wherein the cam device includes a sleeve which encircles and frictionally engages a cylindrical element which is rotatable with the spool, whereby the rotational position of the cam device with respect to the spool may be varied by relative rotation between the spool and cam device, against the action of said frictional engagement.

13. A reel assembly according to any of Claims 1 to 12, including a braking device coupled to said spool to brake rotation thereof.

14. A reel assembly according to Claim 13, wherein said braking device comprises an air brake element or a flywheel rotatable with the spool.

15. A reel assembly according to Claim 14, wherein the braking device is mounted on a rotatable shaft separate from said spool, a drive mechanism being connected between the spool and said shaft so that the shaft rotates with the spool.

16. A reel assembly according to Claim 15, wherein a free-wheel device is provided between the spool and the braking device, enabling the spool to rotate independently of the braking device in one direction.

17. A reel assembly according to any of Claims 1 to 16, wherein the free end of the flexible element has secured thereto a catch device which magnetically engages a retainer device which, in use, is located in a position spaced from the reel assembly.

18. A reel assembly according to any of Claims 1 to 16, wherein the free end of the flexible element has secured thereto a catch device which snaps into mechanical interlocking engagement with a cooperatively shaped retainer device which, in use, is located in a position spaced from the reel assembly.

19. A reel assembly according to Claim 18, wherein the catch device includes at least one snap unit comprising two spaced resilient arms adapted to enter a cavity in the retainer device, the arms being formed respectively with outward projections which snap past corresponding inward projections at the mouth of the cavity, as the snap unit enters the cavity, the inter- engagement between said projections tending to retain the snap unit in the cavity.

20. A reel assembly according to Claim 19, wherein the projections on the arms of the snap unit and the walls of the cavity in the retainer device are cooperatively shaped so as to squeeze said arms together as the snap unit is pushed into the cavity, the width of the arms being sufficient to permit one side thereof then to withdrawn from the cavity, by sideways tilting of the snap unit, while the other sides of the arms remain in engagement with the walls of the cavity, squeezing said arms together.

21. A reel assembly substantially as hereinbefore described with reference to the accompanying drawings.