| Claims 1. An anti ligature device for use with vertical drop coverings, comprising: a housing unit for attachment to vertical blinds containing a rotating member, said rotating member being adapted to receive a pull-cord around it's outer circumference and said rotating member being held in position within said housing by a pin; wherein said pin is adapted to break when placed under a predetermined pressure and wherein said housing further comprises a cutting means which, in use, is positioned below said rotating member. 2. An anti ligature device according to Claim 1 , wherein said pin has a wedge portion. 3. An anti ligature device according to Claim 1 , wherein said pin is provided with a weakened frangible section. 4. An anti ligature device according to any one of the preceding Claims, wherein said pin is, in use, positioned such that each side of said pin is held on a seat or retaining section within said housing. 5. An anti ligature device according to any one of the preceding Claims, wherein said cutting means comprises at least one blade. 6. An anti ligature device according to Claim 5, wherein said blade is an angled blade. 7. An anti ligature device according to either one of Claims 5 or 6, wherein said blade is made from stainless steel. 8. An anti ligature device according to any one of the preceding Claims, wherein said pull-cord is a string, a chain or other suitable cord type structure. 9. An anti ligature device according to any one of the preceding Claims, wherein the housing is provided with a gap greater than the circumference of the wheel on at least one side of the cutting means to allow the rotating member to travel past the cutting means if the pin is caused to break. 10.An anti ligature device according to Claim 9, wherein the space at the side of said cutting means is an internal chamber within said housing. 11.An anti ligature device according to Claim 9, wherein the space at the side of said cutting means is a section of said housing provided with an open section or channel in the housing wall. 12.An anti ligature device as according to any one of the preceding Claims, wherein said housing is in the form of an end-cap for use with the operating mechanism of a set of blinds. 13.An anti ligature device according to any one of the preceding Claims, wherein said housing is formed from an integrally moulded plastic. 14.An anti ligature device toggle adapted to be coupled to a pull-cord for vertical drop coverings, comprising: a housing, having a first aperture at an upper portion and a second aperture at a lower portion when in use, wherein said first and second apertures are adapted to receive and guide said pull- cord through said housing, defining a first longitudinal axis extending through the centre of said first and second apertures; a cord cutting mechanism, adapted to cut said pull-cord at a predetermined pulling force applied to said pull-cord during use. 15.An anti ligature device toggle according to Claim 14, wherein said cord cutting mechanism comprises: cutting means, positioned within said housing such that said pull-cord is cut when taut and in line with said first longitudinal axis at said predetermined pulling force; guiding means, adapted to guide said pulling cord away and around said cutting means while the force applied to said pull-cord is less than said predetermined pulling force. 16.An anti ligature device toggle according to Claim 15, wherein said guiding means comprises a pin having a second longitudinal axis and positioned within said housing such that said second longitudinal axis is offset and substantially perpendicular to said first longitudinal axis. 17.An anti ligature device toggle according to Claim 16, wherein said pin is adapted to break at a predetermined pressure. 18.An anti ligature device toggle according to any one of Claims 16 and 17, wherein said pin has a wedge portion. 19.An anti ligature device toggle according to any one of Claims 16 and 17, wherein said pin is provided with a weakened frangible section. 20.An anti ligature device toggle according to any one of Claims 16 to 19, wherein said pin is, in use, positioned such that each side of said pin is held on a seat or retaining section within the housing. 21.An anti ligature device toggle according to Claim 14, wherein said cord cutting mechanism comprises spring mechanism connecting an upper pull-cord end-portion and a lower pull-cord end-portion of said pull-cord, and cutting means, adapted to be moved towards and into said lower pull-cord end-portion when applying a predetermined pulling force to said pull-cord. 22.An anti ligature device toggle according to Claim 21 , wherein said upper pull-cord end-portion and said lower pull-cord end-portion are disposed on said first longitudinal axis. 23.An anti ligature device toggle according to any one of Claims 21 and 22, wherein said spring mechanism comprises biasing means to move said cutting means towards and into said lower pull-cord end-portion to compromise the integrity of said lower pull-cord end- portion. 24.An anti ligature device toggle according to Claim 23, wherein said biasing means comprises at least one spring. 25.An anti ligature device toggle according to any one of Claims 15 to 24, wherein said cutting means comprises at least one blade. 26.An anti ligature device toggle according to Claim 25, wherein said blade is angled relative to a plane perpendicular to the cutting movement. 27.An anti ligature device toggle according to any one of Claims 25 and 26, wherein said blade is made of stainless steel. 28.An anti ligature device toggle according to any one of Claims 14 to 27, wherein said pull-cord is a string, chain or any other suitable cord type structure. 29.An anti ligature device toggle according to any one of Claims 14 to 28, wherein said housing comprises a first member pivotably coupled to a second member, wherein said first and/or second member is adapted to be moved into an open and closed position allowing access to said cord cutting mechanism. |
The present invention relates to a safety device for use with vertical drop coverings such as window blinds. In particular it relates to a safety device to prevent possible strangulation by the pull-cords associated with window blinds.
Typically, windows are provided with drapery or vertical drop coverings such as blinds to shield the window as required by a user. Such blinds are generally associated with pull-cords which are used to manoeuvre the material covering a window so that it can be raised or lowered as required, or in some cases so the direction of the elements that make up the blinds can be altered. Pull cords are commonly formed as loops which extend from an area near the top of the blind down to a convenient height for a user to grasp the cord.
Throughout this application window blinds or blinds can be taken to cover Venetian blinds, roller blinds and other similar window coverings that are manually actuated using a pull cord.
Unfortunately, the pull cords associated with blinds can be a hazard for small children and there have been many incidents of accidental strangulation. By positioning the lower end of pull-cords at a convenient height for an adult to grasp, pull-cords are often therefore positioned at head height for a child. Accidents can very easily occur if a child becomes entangled in the pull cord, particularly if the pull cord becomes wrapped around the child's neck. Furthermore, there is also a risk to adults, particularly where blinds are provided in secure units, hospitals or prisons where there is a possibility of vulnerable individuals deliberately using the cord to strangle themselves. Previous attempts have been made to try to mitigate the risk of strangulation associated with pull-cords. One option is to provide the cord as a bead type structure such that the cord will snap if a significant weight is placed upon it. Whilst this can be effective, beaded cords easily become entangled due to their bead type structure which obstructs use of the associated blind or covering. This possibility of entanglement can in some cases results in an increased risk of the cord failing to work in the required manner.
Another option is to use a solid rod in place of a cord to turn and tilt the associated blinds. However, this mechanism is cumbersome when used to raise/lower the window blinds and is also prone to failure.
In another case, as described in US5473797, the cord has been retained in a housing made up of two moulded sections, wherein the moulded sections split apart if a child becomes entangled in the cord, such that the cord is released.
Accordingly it is an object of the present invention to provide a device, which obviates or mitigates one or more of the problems associated with the prior art or provides an alternative safety device.
According to a first aspect of the present invention, there is provided an anti ligature device for use with vertical drop coverings, comprising:
a housing unit containing a rotating member, said rotating member being adapted to receive a pull cord around it's outer circumference and said rotating member being held in position within said housing by a pin; wherein said pin is adapted to break when placed under a predetermined pressure and wherein said housing further comprises a cutting means which, in use, is positioned below said rotating member.
Advantageously, the unit is provided as an end cap for attachment to the upper beam of a window blinds, and the pin is adapted to break under a predetermined pressure, which may relate to the weight of a small child pulling on the pull cord. When a pull cord is placed around the rotating member or wheel and sufficient weight is hung from the cord then the pin will snap or give way, allowing the cord to fall from the wheel onto the cutting means or blade below, thus cutting the cord.
In the preferred embodiment, the pin has a wedge portion.
By providing the pin having a wedge portion positioned between the walls of the housing, and preferably located adjacent to one of the housing walls, it will preferentially break or collapse at the thin edge of the wedge when pressure is placed on it. This results in the associated rotating member tilting towards the broken section and the pull cord falling from the outer circumference of the rotating member.
Alternatively the pin may be provided with a weakened frangible section. Preferably the pin is, in use, positioned such that each side of said pin is held on a seat or retaining section within said housing.
Preferably the cutting means comprises at least one blade. Most preferably, said blade is an angled blade. In the preferred embodiment said blade is made from stainless steel.
By providing an angled blade, any cord that is pulled onto the blade will be cut more effectively as the downward force on the cord will act to pull the cord down onto the blade and will also pull the cord along the blade towards its lowest point.
The pull cord may be a string, a chain or other suitable cord type structure. In a preferred embodiment, the housing is provided with sufficient space either side of said cutting means to allow said rotating member to travel past said blade.
By providing sufficient room either side of the blade for the rotating member or wheel to pass, this ensures that even if the wheel was to fall from the pin when the pin collapses the cord will still come into contact with the blade and will not be blocked by the wheel.
The space either side of the cutting means may be either an internal chamber within the housing or, more preferably, a section of the housing provided with an open section or channel in the housing wall.
In the preferred embodiment, said housing is in the form of an end-cap for use with the operating mechanism of a set of blinds.
It is also preferred that the housing is formed from an integrally moulded plastic. According to a second aspect of the present invention, there is provided an anti ligature device toggle adapted to be coupled to a pull cord for vertical drop coverings, comprising:
a housing, having a first aperture at an upper portion and a second aperture at a lower portion when in use, wherein said first and second apertures are adapted to receive and guide said pull cord through said housing, defining a first longitudinal axis extending through the centre of said first and second apertures;
a cord cutting mechanism, adapted to cut said pull cord at a predetermined pulling force applied to said pull cord during use.
This provides the advantage of an anti ligature device that can be easily retrofitted to the pull cords of existing blinds, therefore providing a safety toggle having a simple and robust mechanism to use for existing blinds and that is inexpensive to manufacture.
In a first embodiment of the second aspect of the present invention, the cord cutting mechanism may comprise:
cutting means, positioned within said housing such that said pull cord is cut when taut and in line with said first longitudinal axis at said predetermined pulling force;
guiding means, adapted to guide said pulling cord away and around said cutting means while the force applied to said pull cord is less than said predetermined pulling force.
This provides the advantage that the pull cord may simply be placed into the cord cutting mechanism without any further adjustment or preparation of the pull-cord. The guiding means may comprise a pin having a second longitudinal axis and is positioned within said housing such that said second longitudinal axis is offset and substantially perpendicular to said first longitudinal axis. The pin may be adapted to break at a predetermined pressure.
The pin therefore operates as guiding means to the pull-cord as well as providing a predetermined resistance to the pulling force. Thus, simply exchanging the existing pin adapted to break under a first predetermined pressure with a pin adapted to break under a second predetermined pressure allows different settings for different thresholds when the pin should break and the safety device should cut the cord. For example, a first pin may be suitable for a specific weight of a child, wherein another pin may be used for a specific weight of small animals. The pin may have a wedge portion. The pin may also be provided with a weakened frangible section. Such wedge-portion and/or frangible section may define the predetermined pressure under which the pin breaks releasing the pull cord such that it is cut. The pin may, in use, be positioned such that each side of said pin is held on a seat or retaining section within the housing. This provides the advantage that the pin can be easily exchanged or replaced once broken during use. In a second embodiment of the second aspect of the present invention, the cord cutting mechanism comprises a spring mechanism connecting an upper pull cord end-portion and a lower pull cord end-portion of said pull cord, and cutting means, adapted to be moved towards and into said lower pull cord end-portion when applying a predetermined pulling force to said pull cord. Advantageously, said upper pull cord end-portion and said lower pull cord end-portion may be disposed on said first longitudinal axis. The spring mechanism may comprise biasing means to move said cutting means towards and into said lower pull cord end-portion to compromise the integrity of said lower pull cord end-portion.
Preferably, in the second embodiment, the biasing means may comprise at least one spring.
In a preferred example of this second aspect of the present invention, the cutting means may comprise at least one blade. The blade may be angled relative to a plane perpendicular to the cutting movement and may be made of stainless steel.
Advantageously, the housing may comprise a first member pivotably coupled to a second member, wherein said first and/or second member is adapted to be moved into an open and closed position allowing access to said cord cutting mechanism. This provides the advantage that the toggle can be easily retrofitted to a pull cord of any window blind. The cutting and/or guiding mechanism is disposed within the housing, so an openable housing allows easy access to the guide / cutting means for placing the pull cord and securing the toggle to the pull cord.
In order to provide a better understanding of the present invention, preferred embodiments of the first and second aspect of the present invention will now be described, by way of example only, with reference to the following drawings in which;
Figure 1 shows a top view of the present invention; Figure 2 shows a base view of the present invention; Figure 3 shows a side view showing face A of the present invention;
Figure 4 shows a side view showing face C of the present invention;
Figure 5 shows a pin in situ according to a preferred embodiment of the present invention;
Figure 6 shows an open housing of the first embodiment of the anti ligature device toggle, displaying a pull cord guided through the housing, away and around a blade by a pin;
Figure 7 (a) - (c) shows section plan views of the toggle of Figure 6, (a) in an open position, (b) in a partially closed position, (c) in a closed position, and 7 (d) shows a plan view of the toggle of Figure 6 in a closed position;
Figure 8 shows a section side view of a second embodiment of the anti ligature device toggle, (a) in a first state when the applied pulling force is less than a predetermined force and (b) in a second state when the pulling force is greater than the predetermined force.
A preferred embodiment of the first aspect of the present invention can be seen in Figures 1 to 4. The invention relates to an end cap 1 which is for attachment to the upper beam of a set of blinds and is adapted to cooperatively work with a pull cord to manoeuvre the blinds into a desired position. The end-cap 1 is in the form of a housing which contains a rotatable wheel 2 which is held in position within the housing by a wedge shaped pin 3 running axially through the centre of the wheel 2. The pin 3 having a wedge shaped portion (not shown) is formed as part of the housing and allows the wheel 2 to freely rotate (the pin 3 can be seen most clearly in Figure 5). There is a pull-cord 4 provided, which in general use is positioned around the outer circumference of the wheel 2 such that it extends up one side of the wheel, over the top, and then down the other side of the wheel (as is best seen in Figure 3). In use, the ends 4a and 4b of the pull cord 4 extend down from the end cap 1 to a point, which can easily be reached by an individual wanting to actuate the blind
mechanism.
In alternative embodiments, a pin having a wedge portion may be provided in different forms, for example, as a straight pin with a weakened or frangible section. The pin 3 may be formed integrally with the housing or may be a separately formed element, each end of which sits on seat or shoulder sections formed on the inner surface of the housing or within retaining sections formed within the housing. The wheel must be able to rotate. It is also possible that the wheel 2 is formed integrally with the pin 3, providing that the pin 3 is shaped to allow rotation within the housing. In all cases the pin 3 must be adapted to break, collapse or fracture in some manner when placed under a predetermined amount of stress or pressure. The predetermined amount of stress or pressure required to break the pin 3 must be slightly less than that associated with the hanging weight of a small child or, if required, an animal, but more than the standard pressure that will be placed on the system by simply operating the opening and closing of the blinds. The end-cap 1 is also provided with a cutting blade 5 which is positioned such that when the end-cap 1 is in use attached to a set of blinds, the blade 5 is positioned below the level of the wheel 2. The blade 5 is positioned such that the cutting surface 7 is facing toward the wheel 2. In addition, in the preferred embodiment the blade 5 is positioned such that it runs substantially perpendicular to the diameter of the wheel 2. This ensures that in use the trailing edges of the pull-cord 4a and 4b hang down either side of the blade 5.
In use, the end-cap 1 is fitted to the upper beam of a set of blinds such that the manipulation of the pull cord 4 will operate the opening and closing of the blinds. A trailing edge of the pull cord 4 will extend down one side of the blinds to a point which allows for easy manipulation by a user. If a child or adult becomes entangled in the pull cord 4 such that their body weight is held by the pull-cord, for example in the case that a child was to fall and accidentally hang from the pull-cord 4, then the pin 3 will break or give way at the thinner side of the wedge portion or the frangible portion (not shown) due to the downward pressure exerted on the wheel 2 and therefore on the pin 3 by the pull cord 4. Once the pin 3 breaks preferentially at the thin end, it is pulled down at one end and the wheel 2 tilts accordingly. The pull cord 4 is then dislodged from the outer circumference of the wheel 2 and falls from the wheel down to the cutting surface 7 of the blade 5. As the pull cord 4 is disposed such that one end is hanging down one side of the blade 5 and one end down the other side, then this results in the cord 4 being cut by the cutting surface 7 of the blade 5, releasing the cord 4 and preventing anything hanging from the cord 4.
The preferred embodiment utilises a blade 5 where the cutting surface 7 of the blade 5 is angled in respect of the wheel 2 (as can best be seen in Figure 4). When looking along the length of the blade 5, the cutting surface 7 is closer to the wheel at one side than the other. Therefore, if the pull cord 4 is pulled onto the blade 5, the downward force that pulls it onto the blade 5 will also act to drag the pull cord 4 along the blade from the higher to lower end, resulting in a more efficient cutting of the pull cord 4. Further efficiency of cutting can be obtained if the angled blade 5 is provided as a slightly serrated surface.
It can also be envisage that the blade 5 may be provided as a straight blade rather than an angled blade providing that is sufficiently sharp.
There is also a built-in failsafe mechanism for instances where the pin 3 breaks in such a manner that the entire wheel 2 falls rather than only the pull-cord 4. As shown in Figure 5, the circumference of the wheel 2 is less than the space provided at either side of the blade, such that the wheel 2 is able to freely fall past the blade 5 and not get caught above the blade 5. This ensures that, as the pull-cord 4 is positioned such that each end falls either side of the blade 5, that the pull cord 4 will still come into contact with the blade 5 even if the wheel 2 was to fall.
In all cases the end-cap is configured to act as a safety device wherein sufficient weight is being placed on the pull cord 4 results in the breaking of the pin 3 and the resulting self cutting of the cord 4 to prevent anything hanging from the cord 4.
Referring now to Figures 6 and 7 (a) - (d), a first embodiment of a second aspect of the present invention is a anti ligature device toggle 100 that can be retrofitted to existing window blinds by simply attaching the toggle 100 to the pull cord 4 of the blind. The toggle 100 comprises a housing 112 including cutting means in form of a blade 114 and guiding means 116 in form of a pin. The housing 112 has a first aperture 118 at an upper portion and a second aperture 120 at a lower portion of the toggle in use. First and second aperture 118, 120 are adapted to receive and guide the pull cord 4 through the housing 112, wherein the centres of the first and second aperture 118, 120 define a first longitudinal axis (not shown). In this particular example, the pin 116 is positioned opposite the blade 114 allowing the pull cord to be directed around the blade 114 and out of the housing 112 through the second aperture 120. Preferably, pin 116 is breakable under a predetermined stress or pressure that is caused by a pulling force on the pull cord 4. During operation, the pull cord 4 is pulled down providing a force vector into the direction of the pin 116 and subsequently into the direction of the blade 114. At a pulling force providing a pressure onto the pin 116 that is greater than a predetermined pressure, the pin 116 breaks and releases the pull cord 4, which tautens towards the blade 114, where it is cut in half, accordingly.
The housing 12 may be made of two members 112a and 112b that are pivotably coupled such that the housing 112 can be opened and closed to allow access to the inner mechanism and apertures 118, 120. In order to fit the anti ligature device toggle 100 to a pull cord 4 of an existing blind, the housing 112 is opened and the pull cord 4 is placed into the first and second aperture 118, 120 and around the pin 116 as shown in Figure 7(a), (b). The housing 112 is then closed as shown in Figure 7(c), (d) and the toggle is ready for operation. The housing members 112a, 112b are, for example, hinged together on one side and may be closed and fixed through a snap clip or screw.
The pin 116 may have a frangible or wedge shaped portion that
determines the predetermined pressure necessary to break the pin 116. By providing a frangible section, it is ensured that the pin 116 will break at a specific location of the pin 116 in order to allow free access of the pull cord 4 to the blade 114. The pin 116 may be an integral part of the housing 112 or may be into a shoulder section or pin holder. The shoulder section or pin holder allow easy replacement of a broken pin 116 or exchange with a pin that is adapted to break at a different predetermined pressure.
Referring now to Figure 8 (a) and (b), a second embodiment of the second aspect of the present invention is described by way of a preferred example. The anti ligature device toggle 200 is adapted to be retrofitted to the pull cord of an existing window blind and comprises a housing 212 including a cord cutting mechanism. The housing 212 comprises a first aperture 214 at an upper portion and a second aperture 216 at a lower portion of the toggle 200 in use. The first aperture 214 and the second aperture 216 define a first longitudinal axis (not shown) extending through the centres of the first and second apertures 214, 216. An upper end portion 218a of the pull cord 4 is fed through and fixed to the first aperture 214. A lower end portion 218b of the pull cord 4 is slidably guided through the second aperture 216. The cord cutting mechanism comprises a spring mechanism 215 that couples the upper end portion 218a to the lower end portion 218b of the pull cord 4. The spring mechanism 215 comprises a spring pin 220 fixed to the upper end portion 218a and secured to a spring base plate 222 of a compression coil spring 224 that is slidably received within a sleeve 226. The upper end of the compression coil spring 224 is fixed within the sleeve 226 and the sleeve 226 is coupled to the lower end portion 218b of the pull cord 4 via a fixed retainer 228. A blade 230 is coupled to the spring base plate 222 such that sufficient compression of the coil spring 224 moves the blade towards and into the lower end portion 218b of the pull cord 4 so that the lower end portion 218b of the pull cord is cut eventually. Also, the attached blade 230 may be fixed to the spring base plate 222 at an angle such that the blade 230 is directed
substantially in line with the movement of the compression coil spring 224. During operation, a pulling force on pull cord 4 that exceeds a
predetermined force, causes the compression coil spring 224 to compress into the sleeve 226, moving the blade 230 upwards, towards and into the lower end portion 218b of the pull cord 4, consequently cutting the lower end portion 218b of the pull cord 4, so that the lower end portion 218b slides through the second aperture 216 and out of the housing 212.
Preferably, the sleeve 226 is angled relative to the first longitudinal axis through first and second aperture such that the blade 230 is moved into the pull cord from the side. Also, the upper end portion 218a is fixed to the first aperture 214 in order to provide an opposing force to the pulling force of the lower end portion 218b of the pull cord 4. Figure 8(a) shows the spring mechanism 215 at a pulling force not exceeding a predetermined force, where the compression coil spring 224 is fully extended keeping the blade away from the lower end portion 218b. Figure 8(b) shows the spring mechanism 215 at a pulling force exceeding a predetermined force, where the compression coil spring 224 is compressed into sleeve 226 and blade 230 is moved into the lower end portion 218b cutting the cord so that the lower end portion 218b can slide through the second aperture and out of the housing 212.
"Stiffer" or "softer" compression coil springs 224 may be used to provide different predetermined forces at which the pull cord 4 is cut. Also, any other biasing means may be used instead of the compression coil spring 224 that is adapted to provide a resistance to a pulling force at the lower end portion 218b of the pull cord 4.
In variations of the present invention, alternative pull cords or housing shapes can be envisaged. In additional cutting means can be envisaged other than a standard blade. It is also envisaged that although the preferred embodiment can withstand a weight on the cord which is just less than that of a hanging infant, lower or higher weight thresholds could be used as require, for example a lower weight threshold for pin breakage could be used when the aim is to avoid animals becoming entangled in the cord.