GB2271600A - Cord lock for a blind - Google Patents

Abstract

A cord lock (110) is adapted to engage with a support beam of a blind assembly to guide cord so as to hang vertically alongside a blind. The cord lock (110) comprises a generally elongate body (12) having a cord inlet (14) and a guide path to a cord outlet (16). The body (12) includes a first cord guide roller (18) at or near the cord inlet (14) which has an axis substantially perpendicular to the elongate axis of the body (12). A second cord guide roller (26), provided at or near the cord outlet (16), has an axis substantially perpendicular to that of the first roller (18) and of the elongate body. Frictional locking means (50) at or near the second cord guide roller (26) are operable to prevent movement of cord back through the cord lock (110) under the influence of the weight of the blind. Use of the first cord guide roller (18) helps to reduce wear on the cord lock (110) owing to frictional engagement of the cord with the lock body. <IMAGE>

Description

CORD-LOCK This invention relates to a cord-lock especially for use with a pleated blind.

Pleated blinds and other forms of window blinds, e.g.

"venetian" blinds are commonly operated by means of a cord mechanism. In such mechanisms, the cord is pulled in one direction to raise the blind. In order to reverse the movement of the blind, the cord is released and allowed to move relatively upwardly, allowing the blind to lower under the effect of its own weight.

Such reversed movement, should be controllable, and specifically, it is a requirement of such arrangements that the blinds can be locked or held in a specific orientation. To accomplish this, a cord-lock mechanism is provided adjacent to or as part of the blind construction and through which the cord passes before hanging substantially vertically for use. The cord-lock is operative to hold the cord against the weight of the blind and prevent a reverse movement, except where the cord-lock is released by a specific manipulation of the cord, usually relatively away from the blind. Such cord-locks are known, for example, in UK Patent 2086461 and US Patents 4413664 and 4646808.

One problem with such cord-lock arrangements however, is that where the lock is intended for use with a pleated or "venetian" blind, it will be understood that the cords are arranged relatively horizontally in or through a horizontal beam or bar. The cords passing through the horizontal beam or bar attached to the mechanism, and, before being suspended vertically for use, are required to pass through the cord-lock which is operative to turn the cord through an angle of at least 900 vertically and/or horizontally.

The known cord-lock mechanisms accomplish such diversion of the cord path by defining a cord guide path within the cordlock. The boundaries of such a cord guide path are formed or defined by walls and/or other fixed guide surfaces formed in the body of the cord-lock. The cord-lock itself is sometimes formed of a plastics material which is hence required to be of high quality material in order to reduce wear of the cord and of those parts of the cord-lock which are in frictional engagement with the cord. It will of course be understood that constant wearing of the cord against the plastics material will have a detrimental effect on its surface which can eventually cause the cord lock to fail.

The high quality of plastics required to postpone such failure increases the cost of producing the cord-lock body and is not a permanent solution. It would be an advantage to provide a cord-lock in which the construction overcomes the problems caused by frictional engagement of the cord and the cord lock body.

It is an object of the invention to provide such a cordlock.

The invention therefore provides in a first aspect a cordlock comprising a generally elongate body adapted to engage with a support beam of a blind assembly, the elongate body including a first guide roller arranged in the body to be rotatable about an axis which is substantially at right angles to the body?5 elongate axis and a second guide roller arranged to be rotatable about an axis which is substantially perpendicular to the elongate axis, the lock further including frictional cord locking means located substantially adjacent to the second roller, the elongate body being shaped to provide a cord guide path between a first cord inlet, the cord passing around the first roller and then to the second roller where the cord is guided to a cord outlet arranged to guide the cord substantially vertically with respect to the blind assembly.

In a first preferred embodiment of the invention, the frictiopal cord locking means is a third roller having at each end a pin locating in two guide slots in the elongate body such that the roller is rotatable and is displacable in a substantially vertical axis with respect to the body, the roller having a plurality of frictionally engaging ridges on its surface and arranged such that in one position the roller contacts the second guide roller and in a second position, engages correspondina ridges provided on a wall of the elongate body.

In this embodiment, the cord having been led through the elongate body passes between the second guide roller and the cord-locking roller such that the cord is at least partially engaged with the frictionally engaging ridges on the guide roller. When the cord is pulled relatively upwardly against its normal downward use movement, the locking roller is pulled upwardly in its guide slot until the cord forces engagement of the rollers ridges with the corresponding ridges on the body wall. Thus, the cord is trapped between the two rollers and prevented from further movement. A downward pull on the cord will allow the roller to drop downwardly in its guide slot releasing the cord for further movement of the attached blinds.

Advantageously, the elongate body is provided with a cord outlet which is arranged, in use, substantially at a distance from the blind such that the cord hangs in its normal position a distance therefrom. Thus, the cord can be disengaged from the locking roller by a movement of the cord relatively towards the blind. This will prevent engagement of the roller when it is required to reverse movement of the blind.

In a second embodiment of the invention, the cord-locking means comprises a first U-shaped locking member pivotally attached to the elongate body and suitably arranged to, in a raised position, fit within the cord outlet, the locking means being further provided with a second U shaped locking member pivotally attached to the first locking member typically substantially at 900 to its axis to provide a scissor action between respective bottom edges of the U shaped members.

In this second embodiment, the cord is led over the second guide roller and then passes through the locking means between the scissor action of the two U shaped members. A downward pull of the cord will disengage the scissor action permitting movement of the cord. A normal upward pull against the cord will cause the scissor action to close, thus preventing further movement of the cord. By pulling the cord to move the first Ushaped member out of line with the cord outlet, the scissor action can be disengaged to provide upward movement of the cord where required.

Advantageously, in each embodiment of the invention, the first roller is located on a separate spindle and secured to the elongate body by provision of a top mounting plate covering a normally open channel section of the body member. In this way, assembly of the cord lock is facilitated whilst providing easy access to the or each roller for replacement or repair thereof.

Preferably, the cord lock has at least one cord inlet, suitably two inlets facing in opposite directions, to increase versatility of the lock. Also, it is preferable to provide two or more mounting positions for the first guide roller, preferably one position associated with each inlet.

The invention will now be described further by way of example with reference to the accompanying drawings in which: Fig. 1 is a perspective view of a first embodiment of the invention; and Fig. 2 is a perspective view of a second embodiment of the invention.

Referring firstly to Fig. 1, a first embodiment of the invention is referred to generally by the reference numeral 10 and includes an elongate body 12 formed of a plastics material, for example, by moulding. The body 12 provides at least one cord in,let 14 and a cord outlet 16. The inlet 14 and outlet 16 are arranged facing in directions substantially at right angles to each other.

The elongate body further serves to define a guide path (not shown) between the inlet 14 and outlet 16 by means of shaped body protrusions or walls. In order to reduce frictional engagement of a cord entering at 14 from the right hand side of the body (not shown for clarity) the invention includes a first guide roller 18 located rotatably in the housing adjacent to the cord inlet 14. The roller has an axis of rotation which will be arranged substantially vertically when the cord-lock is in the desired position with respect to the completed blind assembly. The axis of the first guide roller is also arranged substantially at 900 to the elongate axis of the body.The roller 18 is preferably provided with a spindle or shaft 20 which may be of metal or other material, e.g. plastic and is held in place by securement at one end to a hole 22 provided in a lower part of the body 12 and at the other end of the shaft in a corresponding hole (not shown) in a fixing plate 24 which is located over the elongate body 12.

(An alternative mounting position for the first guide roller 18, if the cord is to enter at 14 from the left hand side of the body, is indicated at 21.) A second guide roller 26 is also located in the body 12 relatively adjacent to the cord outlet 16. The guide roller 26 is rotatably mounted on a shaft or by the provision of pins 28 at the end of the roller 26 and journalled in holes 30 provided in side walls of the elongate body 12. It is to be understood that the surfaces of the first and second rollers 18, 26 are substantially smooth in order to overcome frictional engagement with the cords.

The cord-lock 10 is further provided with cord-locking means to hold a cord relatively immobile against the force of an upward pull caused by the weight of the blind (not shown).

In this first embodiment, the cord-locking means is provided by a third locking roller 40 located generally adjacent to the cord outlet 16 and having an axis of rotation generally parallel to that of the second guide roller 26. The locking roller 40 is provided with pins 42 at each end thereof which locate in guide slots 44 arranged in the side walls of the elongate body member 12. These guide slots permit rotational and upward and downward movement of the locking roller 40 with respect to the second guide roller 26.

The locking roller 40 is further provided with a roughened or ridged peripheral surface 46 which acts to frictionally engage a cord guided between the locking roller 46 and the second guide roller 26, and also to frictionally engage corresponding ridges provided on the inside of a front wall 48 of the elongate member.

Operation of this embodiment will be easily understood.

The cord to control the blind mechanism enters through the cord inlet 14, passes around first guide roller 18 and then over second guide roller 26 passing between it and the locking roller 46. A downward pull on the cord to operate the blind mechanism will cause a downward movement of the locking roller 46 allowing its free rotation and hence movement of the cord and rotation of the first and second guide rollers 18, 26.

When the cord is released and the blind mechanism releases the tension therein to pull the cord relatively upwardly, the locking roller 46 is also moved upwardly in its guide slots 44 until the cord is held firmly between the two rollers 26, 40.

The ridged surface 46 of the locking roller 40 engages with the ridges or projections on the inner surface of front wall 48 to prevent further rotation of the locking roller 40. Thus, the cord is prevented from further upward movement.

Release of the locking roller is accomplished by moving the cord relatively toward the blind and towards the rear of the elongate member. This allows the locking roller to drop relatively downwardly in its guide slots releasing its engagement with the ridges on the front wall 48. Upward movement of the cord is thus permitted.

A second embodiment of the invention is shown in Fig. 2 in which the elongate body member and first and second guide rollers are located substantially identically to that of the first embodiments. The only variation in this second embodiment is in the locking means referred to generally by the reference numeral 50. Other parts of the cord-lock remain the same and are given identical reference numerals to that of the first embodiment. In this arrangement, a cord (not shown) is guided through the cord inlet 14 around the first guide roller 18 through guide path defined in the elongate member 12 to a second guide roller 26 rotatably mounted on a shaft or pins 28 located in holes 30 inside walls of the elongate body 12.From there, the cord passes through a cord outlet 16 engaging with the locking means 50 comprising a first U-shaped member 52 of, for example, metal and pivotally mounted to side walls of the elongate member 12.

Such mounting can be by way of pins or securement to the side walls or as shown in Fig. 2, by way of a shaft 54 extending laterally between the elongate body side walls. A second Ushaped member 56, also of metal, is pivotally attached by pins or rivets 58 to the first U-shaped member 52. The two U-shaped members are arranged substantially at right angles to each other such that a scissor action is formed between respective bottom parts 60, 62 of the two U shaped members. The cord is thus trapped between the two members and between the scissor action.

Operation of this embodiment will be understood from the foregoing. The cord that passes between the two U-shaped members and when subjected to a downward pull will disengage the members allowing downward movement of the cords. An upward pull on the cord however, will cause the scissor action to engage pulling the two bottom parts 60, 62 of the U-shaped members closer together to frictionally grip the cord and prevent further upward movement. By pulling the cord relatively towards the blind, i.e towards the rear end of the elongate member, the first U-shaped member 52 is moved out of alignment thereby to allow selective upward movement of the cord.

The invention is not confined to the foregoing details and variations may be made thereto within the scope of the invention.

Claims (12)

1. A cord lock adapted to engage with a support beam of a blind assembly to guide cord so as to hang vertically alongside a blind, the cord lock comprising a generally elongate body having a cord inlet and a guide path to a cord outlet, the body including a first cord guide roller at or near the cord inlet and which has an axis substantially perpendicular to the elongate axis of the body, a second cord guide roller at or near the cord outlet and which has an axis substantially perpendicular to that of the first roller and of the elongate body, and frictional locking means at or near the second cord guide roller and operable to prevent movement of cord back through the cord lock under the influence of the weight of the blind.

2. A cord lock according to claim 1 wherein the cord inlet and cord outlet are arranged to face in substantially perpendicular directions.

3. A cord lock according to claim 1 or 2 which includes means for shielding at least part of the guide path at or near the first cord guide roller.

4. A cord lock according to claim 3 wherein the means for shielding the guide path comprises a releasable cover for the elongate body.

5. A cord lock according to any preceding claim wherein the frictional locking means is a third roller adapted so that, in use, it is rotatable and displaceable upwardly towards and downwardly away from the second guide roller for respectively locking and releasing cord between the second and third rollers

6. A cord lock according to claim 5 wherein the third roller has at each end a pin which engages in a respective guide slot in the elongate body to permit the displacement of the roller.

7. A cord lock according to claim 5 or 6 wherein the third roller has a plurality of surface formations adapted to engage matching formations on the elongate body.

8. A cord lock according to any one of claims 1 to 4 wherein the frictional locking means comprises a pair of first and second locking members, the first member being pivotally attached to the elongate body and the second member pivotally attached to the first member and capable of providing a scissor action for selectively locking cord between them.

9. A cord lock according to any preceding claim having two cord inlets facing in substantially opposite directions.

10. A cord lock according to claim 9 having alternative mounting positions adjacent each inlet for a first cord guide rollers.

11. A cord lock substantially as hereinbefore described with reference to, and as illustrated in, either of the accompanying Fig. 1 or Fig. 2.

12. A blind assembly having a cord lock as claimed in any preceding claim.