WO2012125036A1 - Safety coupling for a roller screen tension cord - Google Patents

Safety coupling for a roller screen tension cord Download PDF

Info

Publication number
WO2012125036A1
WO2012125036A1 PCT/NL2012/050160 NL2012050160W WO2012125036A1 WO 2012125036 A1 WO2012125036 A1 WO 2012125036A1 NL 2012050160 W NL2012050160 W NL 2012050160W WO 2012125036 A1 WO2012125036 A1 WO 2012125036A1
Authority
WO
WIPO (PCT)
Prior art keywords
coupling
breaking device
toothed wheel
housing part
chain
Prior art date
Application number
PCT/NL2012/050160
Other languages
French (fr)
Inventor
Bastiaan Franciscus Klein Tuente
Ruben Hubert Jan De Vries
Harry Davids
Wouter Hendriks
Original Assignee
Coulisse B.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from NL2006404A external-priority patent/NL2006404C2/en
Application filed by Coulisse B.V. filed Critical Coulisse B.V.
Publication of WO2012125036A1 publication Critical patent/WO2012125036A1/en

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
    • E06B—FIXED OR MOVABLE CLOSURES FOR OPENINGS IN BUILDINGS, VEHICLES, FENCES OR LIKE ENCLOSURES IN GENERAL, e.g. DOORS, WINDOWS, BLINDS, GATES
    • E06B9/00—Screening or protective devices for wall or similar openings, with or without operating or securing mechanisms; Closures of similar construction
    • E06B9/24—Screens or other constructions affording protection against light, especially against sunshine; Similar screens for privacy or appearance; Slat blinds
    • E06B9/26—Lamellar or like blinds, e.g. venetian blinds
    • E06B9/28—Lamellar or like blinds, e.g. venetian blinds with horizontal lamellae, e.g. non-liftable
    • E06B9/30—Lamellar or like blinds, e.g. venetian blinds with horizontal lamellae, e.g. non-liftable liftable
    • E06B9/32—Operating, guiding, or securing devices therefor
    • E06B9/326—Details of cords, e.g. buckles, drawing knobs
    • E—FIXED CONSTRUCTIONS
    • E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
    • E06B—FIXED OR MOVABLE CLOSURES FOR OPENINGS IN BUILDINGS, VEHICLES, FENCES OR LIKE ENCLOSURES IN GENERAL, e.g. DOORS, WINDOWS, BLINDS, GATES
    • E06B9/00—Screening or protective devices for wall or similar openings, with or without operating or securing mechanisms; Closures of similar construction
    • E06B9/24—Screens or other constructions affording protection against light, especially against sunshine; Similar screens for privacy or appearance; Slat blinds
    • E06B9/26—Lamellar or like blinds, e.g. venetian blinds
    • E06B9/28—Lamellar or like blinds, e.g. venetian blinds with horizontal lamellae, e.g. non-liftable
    • E06B9/30—Lamellar or like blinds, e.g. venetian blinds with horizontal lamellae, e.g. non-liftable liftable
    • E06B9/32—Operating, guiding, or securing devices therefor
    • E06B9/326—Details of cords, e.g. buckles, drawing knobs
    • E06B2009/3265—Emergency release to prevent strangulation or excessive load

Definitions

  • the present invention relates to a breaking device for a chain of a screen, such as a window covering, comprising a housing formed by a first housing part and a second housing part, that are attachable to each other by a detachable coupling, a first sprocket and a first toothed wheel, that are connected to each other and are arranged in the first housing part, wherein a first chain engages on the first sprocket, a second toothed wheel, that is arranged in the second housing part, wherein the breaking device is arranged to transfer a pulling force on one side of the chain, via at least the first sprocket, the first toothed wheel and the second toothed wheel, to a rotatable shaft on which the screen is attached, wherein the coupling between the first housing part and the second housing part releases when the pulling force at both sides of the chain reaches or exceeds a predetermined threshold value, wherein the breaking device further comprises a third toothed wheel, that engages the first toothed wheel with
  • Such a breaking device is indispensable in chain operated screens to ensure the safety of particularly younger children. As soon as a child gets entangled in the chain, the breaking device will fall apart into the first and second housing part releasing the chain from the screen.
  • breaking device An example of such a breaking device is known from the Chinese utility model CN201695932U.
  • the known breaking device is intended to be received in a chain of a screen and comprises two toothed wheels that are mutually in engagement.
  • each toothed wheel a chain is wrapped, whereby one chain serves for the manual operation and the other chain serves for driving the rotatable shaft of the screen.
  • the coupling between the first and second housing part is formed by two click couplings that are arranged on opposite sides of the first and second housing part.
  • the known breaking device has the drawback that it can get lop-sided during operation as a consequence whereof the chain might block causing the dick coupling to release even before the predetermined threshold value has been reached.
  • the known breaking device therefore should be attached to the fixed world, for instance to a wall next to the screen, to ensure an optimal functioning.
  • the present invention has for its purpose to provide a breaking device according to the preamble that lifts this drawback.
  • the breaking device comprises a third toothed wheel, that engages the first toothed wheel with the second toothed wheel, wherein the detachable coupling comprises a first coupling and a second coupling.
  • a breaking device according to the preamble of claim 1 is known from
  • the known breaking device comprises one pair of third toothed wheels and one pair of click couplings.
  • the pair of third toothed wheels has for its purpose to enhance the ease of operation of the known breaking device. Indeed, by application of in-between toothed wheels, the first and second sprocket will rotate in the same direction during operation of the chain.
  • the present invention has for its purpose to improve the known breaking device.
  • the breaking device according to the invention is thereto characterized in that the first coupling and the second coupling are arranged such that near the second coupling a preferred side is defined for operation of the lifting of the screen, whereby higher pulling forces are possible at the part of the chain that extends near the preferred side, without the coupling releasing, than at the part of the chain that extends near a non-preferred side, which non-preferred side lies near the first coupling.
  • the breaking device according to the invention is suitable for use with all types of window coverings, even window coverings that are large and heavy and necessitate high pulling forces to lift, for example heavy packages of lamellae. Due to the asymmetrical first and second coupling and the definition of a preferred side the breaking device can withstand at that preferred side pulling forces that are higher than the preset threshold value for releasing the coupling, whereby the breaking device remains operational.
  • the second coupling comprises a sliding connection having a sliding direction under an angle a with the direction in which the pulling force is exerted, wherein a ⁇ 0.
  • the resulting force on the second coupling will have at least one component that essentially is perpendicular to the sliding direction that will oppose breaking of the second coupling.
  • the sliding connection is form-fitting. Being form-fitting only allows sliding in the sliding direction.
  • the sliding connection comprises a cooperating rib and groove.
  • a is chosen such that the resulting force due to exerting the pulling force on the chain part extending near the preferred side lies substantially perpendicular to the sliding direction.
  • the breaking device remains operational at very high pulling forces.
  • the second coupling is a pivotable coupling, which second coupling releases at a pulling force equal to or greater than the predetermined threshold value, wherein the first coupling releases at a lower pulling force than the second coupling and wherein the third toothed wheel is arranged closer to the second coupling than to the first coupling.
  • the breaking device will also remain operational at higher pulling forces in the alternative preferred embodiment.
  • the decentralized positioning of the in-between toothed wheel reduces the reaction force that the first and the second toothed wheel exert on each other in the known breaking device and reduces consequently the contribution of that reaction force to the pulling force due to which the known breaking device already breaks at a pulling force that is lower than the threshold value.
  • the alternative breaking device will open first at the location of the first coupling, when a pulling force is exerted on both sides of the chain, but will remain operational until the moment at which the pulling force at the preferred side reaches the predetermined threshold value, after which the breaking device according to the invention will open instantaneously.
  • the first coupling is a click coupling.
  • first and the second housing part are provided on facing circumferential edges with the first and the second coupling, that preferably lie opposite.
  • the third toothed wheel is arranged in the second housing part.
  • the second housing part comprises a second sprocket that is connected to the second toothed wheel, wherein a second chain can engage around the second sprocket.
  • the free hanging embodiment is suitable for attachment in the chain of the screen.
  • the second housing part is arranged for attachment to an elongated housing of the screen, wherein the rotatable shaft lies, such that the second toothed wheel drives the rotatable shaft.
  • the fixed embodiment is suitable for attachment to one end of the elongated housing of the screen.
  • Figure 1 shows a schematic view of a screen provided with a first preferred embodiment of a breaking device according to the invention in operational position;
  • Figure 2 shows a schematic view of the screen of figure 1 with the breaking device in non-operational position
  • Figure 3 shows a detailed view of the breaking device of figures 1 and 2 in operational position
  • Figure 4 shows the breaking device of figure 3 in non-operational position
  • FIGS 5A and 5B show schematic views from different viewpoints of the breaking device of figures 1 through 4 with disassembled parts
  • Figure 6 shows a schematic view of a screen provided with a second preferred embodiment of a breaking device according to the invention in operational position;
  • Figure 7 shows a schematic view of the screen of figure 6 with the breaking device in non-operational position
  • Figure 8 shows a front view with removed parts of the breaking device of figures 6 and 7 in operational position
  • Figure 9 shows a schematic view of the breaking device of figures 6 through 8 with disassembled parts
  • Figure 10 shows a schematic view of a screen provided with a third preferred embodiment of a breaking device according to the invention in operational position;
  • Figure 11 shows a schematic view of the screen of figure 10 with the breaking device in non-operational position
  • Figure 12 shows a detailed view of the breaking device of figures 10 and 1 in operational position
  • Figure 13 shows the breaking device of figure 12 in non-operational position
  • Figures 14A and 14B show schematic views from different viewpoints of the breaking device of figures 10 through 13 with disassembled parts.
  • Figures 1 and 2 show a schematic view of a screen 100, such as a window covering, provided with a breaking device 1 according to a first preferred
  • a roller blind system 100 that is provided with a curtain or cloth 102 that is attached to an elongated housing or rail 103.
  • a rotatable shaft (not shown), that is operational by means of a chain.
  • the breaking device 1 according to the invention is accommodated.
  • the breaking device 1 assumes an operational position, wherein the user can operate the screen 100 by means of the chain.
  • the breaking device 1 assumes the non-operational position, wherein the breaking device 1 is split in two parts, such that the lower part of the chain is detached from the rail 103.
  • the breaking device 1 is arranged such, that the non-operational position is assumed, when the pulling force, exerted by a user on both sides of the chain, reaches or exceeds a predetermined threshold value. This is illustrated by means of the weight 104 that determines the pulling force.
  • a suitable threshold value can be calculated on the basis of a maximum allowable weight of for example 8 kilograms, pulling on both sides of the chain.
  • FIGS 3 and 4 show the breaking device 1 with cut-away parts in the operational, respectively non-operational position.
  • Figures 5A and 5B show the breaking device 1 with disassembled parts from different viewpoints.
  • Breaking device 1 according to the invention comprises a first or lowest housing part 10 and a second or upper housing part 20 that can be coupled in a detachable manner.
  • the first housing part 10 comprises two plate shaped parts 10A and 10B.
  • the second housing part 20 also comprises two plate shaped parts 20A and 20B.
  • the plate shaped parts need to be pair wise attached to each other while clamping various parts, that will be described in more detail herein below.
  • first housing part 10 a first toothed wheel 1 1 and a first sprocket 12 are received, that are connected to each other.
  • second housing part 20 a second toothed wheel 21 and a second sprocket 22 are received, that are connected to each other.
  • first toothed wheel 11 and the first sprocket 12 are arranged on opposite sides of a plate shaped element and form an integrated part 13.
  • the second toothed wheel 21 and the second sprocket 22 are in a similar way arranged on both sides of a plate shaped element and together form an integrated part 23. Both integrated parts 13, 23 can be manufactured by means of injection moulding.
  • first housing part 10 lies a shaft 14 on which the integrated part 13 can be arranged.
  • second housing part 20 lies a shaft 24 on which the integrated part 23 can be arranged.
  • a chain 15 is attached and around the second sprocket 22 a chain 25 is attached.
  • the chain 15 serves as an operational chain for the user.
  • the chain 25 is connected to a transmission in the rail 103 for driving the rotatable shaft (not shown) present therein. Suitable transmissions are known in the relevant art.
  • the integrated parts 13 and 23 engage onto each other by means of an in- between third toothed wheel 31. More specifically this third toothed wheel 31 engages onto the first toothed wheel 11 and onto the second toothed wheel 21.
  • the third toothed wheel 31 ensures the first toothed wheel 11 together with the first sprocket 12 to follow the same direction of rotation, in this example clockwise, as the second toothed wheel 21 together with the second sprocket 22 during operation of the chain 15 with a pulling force Fi. Consequently the force F 2 that is exerted on the second chain 25 lies in the same direction as the force Fi.
  • the coupling between the first housing part 0 and the second housing part 20 is partly performed as a click connection.
  • the click connection is arranged on one side of the facing circumferential edges of the first housing part 10 and the second housing part 20.
  • the click connection is formed by an elastic lip 42 and a first recess 43 corresponding to the shape of this lip.
  • the elastic lip 42 lies on the first housing part 10
  • the first recess 43 lies on the second housing part 20.
  • the coupling further comprises a pivotable connection that is arranged on an opposite side of the facing circumferential edges of both the first housing part 10 as well as the second housing part 20.
  • the pivotable connection is formed by a hook-like element 44 and a second recess 45 corresponding to the shape of the hook-like element.
  • the hook-like element 44 lies on the first housing part 10 and the second recess 45 lies on the second housing part 20. If so desired these positions of lip 42 and corresponding recess 43 can be interchanged. This is also valid for the positions of the barb 44 and the corresponding recess 45.
  • the third or in-between toothed wheel 31 lies off-centre in the housing 10, 20 and lies closer to the pivotable connection 44, 45 than to the click connection 42, 43.
  • a shaft 34 for the third toothed wheel lies in the housing 10, 20. This shaft 34 preferably lies in the second housing part 20.
  • the coupling of the breaking device 1 according to the invention should be designed such that the click connection 42, 43 releases earlier, i.e. at a lower pulling force, than the pivotable connection 44, 45.
  • the breaking device 1 assumes the operational position if the pulling force lies below a predetermined threshold value. If the pulling force at both sides reaches or exceeds the predetermined threshold value, both the click connection and the pivotable connection will open as a consequence whereof the first housing part 10 and the second housing part 20 will decouple.
  • the click connection will release first, but the pivotable connection will be maintained.
  • the first toothed wheel 11 and the second toothed wheel 21 will remain in engagement with the third toothed wheel 31 as long as the pivotable connection is maintained. Only when the pulling force actually reaches the predetermined threshold value, the pivotable connection will release due to which the first toothed wheel 11 and the third toothed wheel 31 will disengage. The breaking device 1 then is no longer operational.
  • a preferred side arises, that can carry heavier loads than the opposite side close to the click connection or first coupling. This can be used advantageously by accommodating the breaking device 1 in the chain 15; 25 in such a way that lifting of the screen 100 takes place by exerting a pulling force on that preferred side.
  • the preferred side can withstand heavier loads and will remain operational at higher pulling forces.
  • Figures 6 and 7 show a schematic view of a screen, such as a window covering 200, provided with a breaking device 101 according to a second preferred embodiment of the invention.
  • a folding blind system 200 is shown, that is provided with a cloth 202 that is attached by means of cords to an elongated housing or rail 203.
  • a rotatable shaft (not shown), that is operational by means of a chain.
  • the breaking device 1 according to the invention is attached to the elongated housing 203.
  • the breaking device 101 assumes an operational position, wherein the user can operate the screen 200 by means of the chain.
  • the breaking device 101 assumes the non-operational position, wherein the breaking device 101 is split in two parts, such that the lower part of the chain is detached from the rail 203.
  • the breaking device 101 according to the invention is arranged such, that the non-operational position is assumed, when the pulling force, exerted by a user on both sides of the chain, reaches or exceeds a predetermined threshold value.
  • a suitable threshold value can be calculated on the basis of a maximum allowable weight of for example 8 kilograms, pulling on both sides of the chain.
  • Figure 8 shows the breaking device 101 with cut-away parts in the operational position.
  • Figure 9 shows the breaking device 101 with cut-away parts in the non- operational position.
  • Breaking device 101 according to the invention comprises a first or lowest housing part 110 and a second or upper housing part 120 that can be coupled in a detachable manner.
  • the first housing part 1 10 comprises two plate shaped parts 110A and 110B.
  • the second housing part 120 also comprises two plate shaped parts 120A and 120B.
  • the (plate shaped) parts need to be pair wise attached to each other while clamping various parts, that will be described in more detail herein below.
  • first housing part 110 a first toothed wheel 111 and a first sprocket 112 are received, that are connected to each other.
  • second housing part 120 a second toothed wheel 121 is received.
  • first toothed wheel 111 and the first sprocket 112 are arranged on opposite sides of a plate shaped element and form an integrated part 1 13.
  • the integrated part 113 can be manufactured by means of injection moulding.
  • first housing part 110 lies a shaft 114 on which the integrated part 1 13 can be arranged.
  • second housing part 120 lies an unround attachment member 124 on which the second toothed wheel 121 can be arranged.
  • the unround attachment member 124 is fixedly connected to the rotatable shaft (not shown) that can be inserted into holder 205.
  • Suitable holders and attachment members are known in the relevant art.
  • the chain 115 serves as an operational chain for the user.
  • the integrated part 113 and the second toothed wheel 121 engage onto one another by means of an in-between third toothed wheel 131. More specifically this third toothed wheel 131 engages onto the first toothed wheel 111 and onto the second toothed wheel 121.
  • the third toothed wheel 131 ensures the first toothed wheel 111 together with the first sprocket 1 12 to follow the same direction of rotation, in this example clockwise, as the second toothed wheel 121 during operation of the chain 115 with a pulling force
  • the click connection is arranged on one side of the facing circumferential edges of the first housing part 110 and the second housing part 120.
  • the click connection is formed by an elastic lip 142 and a first protrusion 143 corresponding to the shape of this lip.
  • the elastic lip 1 2 lies on the first housing part 110 and the first protrusion 143 lies on the second housing part 120.
  • the coupling further comprises a pivotable connection that is arranged on an opposite side of the facing circumferential edges of both the first housing part 110 as well as the second housing part 120.
  • the pivotable connection is formed by a hook-like element 144 and a second protrusion 145 corresponding to the shape of the hook-like element.
  • the hook-like element 144 lies on the first housing part 110 and the second protrusion 1 5 lies on the second housing part 120. If so desired these positions of lip 1 2 and
  • corresponding protrusion 143 can be interchanged. This is also valid for the positions of the barb 144 and the corresponding protrusion 145.
  • the coupling of the breaking device 101 according to the invention should be designed such that the click connection 142, 143 releases earlier, i.e. at a lower pulling force, than the pivotable connection 144, 145.
  • the breaking device 101 assumes the operational position if the pulling force lies under a predetermined threshold value. If the pulling force at both sides reaches or exceeds the predetermined threshold value, both the click connection and the pivotable connection will open as a consequence whereof the first housing part 1 10 and the second housing part 120 will decouple.
  • the click connection will release first, but the pivotable connection be maintained. Since the first housing part 1 10 is attached to the fixed world by means of the rail 203, the first toothed wheel 111 and the second toothed wheel 121 will remain in engagement with the third toothed wheel 31 as long as the pivotable connection is maintained. Only when the pulling force actually reaches the predetermined threshold value, the pivotable connection will release due to which the first toothed wheel 111 and the second wheel 131 will disengage. The breaking device 101 is then no longer operational.
  • a preferred side arises at the side of the stronger pivotable or second coupling that can carry heavier loads than the opposite side close to the click coupling or first coupling. This can be used advantageously by attaching the breaking device 101 to the rail 203 in such a way that lifting of the screen 200 takes place by exerting a pulling force on that preferred side.
  • the preferred side can withstand heavier loads and will remain operational at higher pulling forces.
  • Figures 10 and 1 show a schematic view of the screen 100 of figures 1 and 2 provided with a breaking device 201 according to a third preferred embodiment of the invention.
  • the breaking device 201 according to the invention is accommodated.
  • the breaking device 201 assumes an operational position, wherein the user can operate the screen 100 by means of the chain.
  • the breaking device 201 assumes the non-operational position, wherein the breaking device 201 is split in two parts, such that the lower part of the chain is detached from the rail 103.
  • the breaking device 201 according to the invention is arranged such, that the non-operational position is assumed, when the pulling force, exerted by a user on both sides of the chain, reaches or exceeds a predetermined threshold value. This is illustrated by means of the weight 104 that determines the pulling force.
  • a suitable threshold value can be calculated on the basis of a maximum allowable weight of for example 8 kilograms, pulling on both sides of the chain.
  • FIGS 12 and 13 show the breaking device 201 with cut-away parts in the operational, respectively non-operational position.
  • Figures 14A and 14B show the breaking device 201 with disassembled parts from different viewpoints.
  • Breaking device 201 according to the invention comprises a first or lowest housing part 210 and a second or upper housing part 220 that can be coupled in a detachable manner.
  • the first housing part 210 comprises two plate shaped parts 210A and 210B.
  • the second housing part 220 also comprises two plate shaped parts 220A and 220B.
  • the plate shaped parts need to be pair wise attached to each other while clamping various parts, that will be closer described herein below.
  • first housing part 210 a first toothed wheel 21 and a first sprocket 212 are received, that are connected to each other.
  • second housing part 220 a second toothed wheel 221 and a second sprocket 222 are received, that are connected to each other.
  • first toothed wheel 211 and the first sprocket 212 are arranged on opposite sides of a plate shaped element and form an integrated part 213.
  • the second toothed wheel 221 and the second sprocket 222 are in a similar way arranged on both sides of a plate shaped element and together form an integrated part 223. Both integrated parts 213, 223 can be manufactured by means of injection moulding.
  • first housing part 210 lies a shaft 214 on which the integrated part 213 can be arranged.
  • second housing part 220 lies a shaft 224 on which the integrated part 223 can be arranged.
  • a chain 215 is attached and around the second sprocket 222 a chain 225 is attached.
  • the chain 215 serves as an operational chain for the user.
  • the chain 225 is connected to a transmission in the rail 103 for driving the rotatable shaft (not shown) present therein. Suitable transmissions are known in the relevant art.
  • the integrated parts 2 3 and 223 engage onto one another by means of an in- between third toothed wheel 231. More specifically this third toothed wheel 231 engages onto the first toothed wheel 211 and onto the second toothed wheel 221.
  • the third toothed wheel 231 ensures the first toothed wheel 211 together with the first sprocket 212 to follow the same direction of rotation, in this example clockwise, as the second toothed wheel 221 together with the second sprocket 222 during operation of the chain 215 with a pulling force Fi . Consequently the force F 2 that is exerted on the second chain 225 lies in the same direction as the force
  • the coupling between the first housing part 210 and the second housing part 220 is partly performed as a click connection.
  • the click connection is arranged on one side of the facing circumferential edges of the first housing part 210 and the second housing part 220.
  • the click connection is formed by an elastic lip 242 and a first recess 243 corresponding to the shape of this lip.
  • the elastic lip 242 lies on the first housing part 210 and the first recess 243 lies on the second housing part 220.
  • the lip comprises two parts: 242A and 242B.
  • the coupling further comprises a sliding connection.
  • the sliding connection is formed by a rib 244 and a groove 245 corresponding to the shape of the rib.
  • the rib can be slid into the groove in a sliding direction S under an angle a with the direction F1 , wherein a ⁇ 0.
  • the sliding connection is form-fitting, such that the sliding connection is maintained when a force perpendicular to the sliding direction S.
  • the rib 244 lies on the first housing part 210 and the second groove 245 lies on the second housing part 220. If so desired these positions of lip 242 and corresponding recess 243 can be interchanged. This is also valid for the positions of the rib 244 and the corresponding groove 245.
  • the sliding connection is arranged on facing second circumferential edges of the first housing part 210 and the second housing part 220.
  • the first and second circumferential edges are under an angle ⁇ , wherein 0 ⁇ ⁇ ⁇ 180 degrees.
  • the third or in-between toothed wheel 231 lies in the centre in the housing 210, 220.
  • a shaft 234 for the third toothed wheel lies in the housing 210, 220.
  • This shaft 234 preferably lies in the second housing part 220.
  • a preferred side arises, that can carry heavier loads than the opposite side close to the click coupling or first coupling.
  • This can be used advantageously by accommodating the breaking device 201 in the chain 215; 225 in such a way that lifting of the screen 100 takes place by exerting a pulling force on the part of the chain extending along that preferred side.
  • the preferred side can withstand heavier loads and will always remain operational at higher pulling forces.
  • the coupling of the breaking device 201 according to the invention should be designed such that the click connection 242, 243 releases when the pulling force, that a user essentially exerts simultaneously on both sides of the chain reaches or exceeds a predetermined threshold value.
  • breaking device 201 During operation the breaking device 201 will remain hanging right due to the third toothed wheel 231 that makes sure the forces F1 and F2 lie in line.
  • the breaking device 201 assumes the operational position as long as the pulling force F1 exerted on the part of the chain extending along the non-preferred side lies under a predetermined threshold value. If the pulling force at both sides of the chain simultaneously reaches or exceeds the predetermined threshold value, the click connection and consequently the sliding connection will open as a consequence whereof the first housing part 210 and the second housing part 220 will decouple. This is illustrated by means of F1 , the reaction force between the toothed wheels (not shown) and the resulting force F R perpendicular to the sliding direction S. The form- fitting sliding connection will then be maintained.
  • the present invention is not limited to the embodiments shown and described.
  • the invention also extends to all combinations of the shown and described embodiments and especially to the combination of the second and the third embodiment.
  • the click coupling (142, 143) and the pivotable coupling (144, 145) can surely also be replaced by the click coupling (242, 243) and the sliding coupling (244, 245) of the third, free hanging embodiment.

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  • Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Operating, Guiding And Securing Of Roll- Type Closing Members (AREA)
  • Curtains And Furnishings For Windows Or Doors (AREA)

Abstract

The invention relates to a breaking device (1) for a chain of a screen (100), comprising a housing having a detachable couplable first and second housing part (210, 220). The breaking device further comprises a third toothed wheel that brings the first toothed wheel in engagement with the second toothed wheel. The coupling between the first housing part and the second housing part releases when the pulling force reaches or exceeds a predetermined threshold value. The coupling comprises a first and a second coupling that are arranged such that near the second coupling a preferred side is defined for operation of the lifting of the screen, whereby higher pulling forces are possible without the coupling releasing, than at a non-preferred side, which non-preferred side lies near the first coupling.

Description

SAFETY COUPLING FOR A ROLLER SCREEN TENSION CORD
The present invention relates to a breaking device for a chain of a screen, such as a window covering, comprising a housing formed by a first housing part and a second housing part, that are attachable to each other by a detachable coupling, a first sprocket and a first toothed wheel, that are connected to each other and are arranged in the first housing part, wherein a first chain engages on the first sprocket, a second toothed wheel, that is arranged in the second housing part, wherein the breaking device is arranged to transfer a pulling force on one side of the chain, via at least the first sprocket, the first toothed wheel and the second toothed wheel, to a rotatable shaft on which the screen is attached, wherein the coupling between the first housing part and the second housing part releases when the pulling force at both sides of the chain reaches or exceeds a predetermined threshold value, wherein the breaking device further comprises a third toothed wheel, that engages the first toothed wheel with the second toothed wheel, wherein the detachable coupling comprises a first coupling and a second coupling.
Such a breaking device is indispensable in chain operated screens to ensure the safety of particularly younger children. As soon as a child gets entangled in the chain, the breaking device will fall apart into the first and second housing part releasing the chain from the screen.
An example of such a breaking device is known from the Chinese utility model CN201695932U. The known breaking device is intended to be received in a chain of a screen and comprises two toothed wheels that are mutually in engagement.
Around each toothed wheel a chain is wrapped, whereby one chain serves for the manual operation and the other chain serves for driving the rotatable shaft of the screen. The coupling between the first and second housing part is formed by two click couplings that are arranged on opposite sides of the first and second housing part.
The known breaking device has the drawback that it can get lop-sided during operation as a consequence whereof the chain might block causing the dick coupling to release even before the predetermined threshold value has been reached. The known breaking device therefore should be attached to the fixed world, for instance to a wall next to the screen, to ensure an optimal functioning.
The present invention has for its purpose to provide a breaking device according to the preamble that lifts this drawback.
The breaking device according to the invention thereto comprises a third toothed wheel, that engages the first toothed wheel with the second toothed wheel, wherein the detachable coupling comprises a first coupling and a second coupling.
Due to the third or in-between toothed wheel the breaking device will remain hanging right during operation of the screen.
A breaking device according to the preamble of claim 1 is known from
EP1319793. The known breaking device comprises one pair of third toothed wheels and one pair of click couplings. The pair of third toothed wheels has for its purpose to enhance the ease of operation of the known breaking device. Indeed, by application of in-between toothed wheels, the first and second sprocket will rotate in the same direction during operation of the chain.
The present invention has for its purpose to improve the known breaking device.
The breaking device according to the invention is thereto characterized in that the first coupling and the second coupling are arranged such that near the second coupling a preferred side is defined for operation of the lifting of the screen, whereby higher pulling forces are possible at the part of the chain that extends near the preferred side, without the coupling releasing, than at the part of the chain that extends near a non-preferred side, which non-preferred side lies near the first coupling.
The breaking device according to the invention is suitable for use with all types of window coverings, even window coverings that are large and heavy and necessitate high pulling forces to lift, for example heavy packages of lamellae. Due to the asymmetrical first and second coupling and the definition of a preferred side the breaking device can withstand at that preferred side pulling forces that are higher than the preset threshold value for releasing the coupling, whereby the breaking device remains operational.
According to a first preferred embodiment the second coupling comprises a sliding connection having a sliding direction under an angle a with the direction in which the pulling force is exerted, wherein a≠0. In this preferred embodiment the resulting force on the second coupling will have at least one component that essentially is perpendicular to the sliding direction that will oppose breaking of the second coupling.
In a further development of the preferred embodiment the sliding connection is form-fitting. Being form-fitting only allows sliding in the sliding direction.
According to a practical preferred embodiment the sliding connection comprises a cooperating rib and groove.
In an optimal embodiment a is chosen such that the resulting force due to exerting the pulling force on the chain part extending near the preferred side lies substantially perpendicular to the sliding direction. In this optimal embodiment the breaking device remains operational at very high pulling forces.
In an alternative preferred embodiment the second coupling is a pivotable coupling, which second coupling releases at a pulling force equal to or greater than the predetermined threshold value, wherein the first coupling releases at a lower pulling force than the second coupling and wherein the third toothed wheel is arranged closer to the second coupling than to the first coupling.
The breaking device will also remain operational at higher pulling forces in the alternative preferred embodiment. By the decentralized positioning of the in-between toothed wheel close to the second coupling a preferred side will arise for the operation of the lifting of the screen, whereby higher pulling forces are possible at that preferred side without the housing breaking. The decentralized positioning of the in-between toothed wheel reduces the reaction force that the first and the second toothed wheel exert on each other in the known breaking device and reduces consequently the contribution of that reaction force to the pulling force due to which the known breaking device already breaks at a pulling force that is lower than the threshold value.
Due to the two-part coupling with different threshold values, the alternative breaking device will open first at the location of the first coupling, when a pulling force is exerted on both sides of the chain, but will remain operational until the moment at which the pulling force at the preferred side reaches the predetermined threshold value, after which the breaking device according to the invention will open instantaneously.
Preferably the first coupling is a click coupling.
In a further preferred embodiment of the breaking device according to the invention the first and the second housing part are provided on facing circumferential edges with the first and the second coupling, that preferably lie opposite.
According to yet another preferred embodiment of the breaking device the third toothed wheel is arranged in the second housing part.
In a free hanging preferred embodiment the second housing part comprises a second sprocket that is connected to the second toothed wheel, wherein a second chain can engage around the second sprocket. The free hanging embodiment is suitable for attachment in the chain of the screen.
In a fixed embodiment the second housing part is arranged for attachment to an elongated housing of the screen, wherein the rotatable shaft lies, such that the second toothed wheel drives the rotatable shaft. The fixed embodiment is suitable for attachment to one end of the elongated housing of the screen.
Figure 1 shows a schematic view of a screen provided with a first preferred embodiment of a breaking device according to the invention in operational position;
Figure 2 shows a schematic view of the screen of figure 1 with the breaking device in non-operational position;
Figure 3 shows a detailed view of the breaking device of figures 1 and 2 in operational position;
Figure 4 shows the breaking device of figure 3 in non-operational position;
Figures 5A and 5B show schematic views from different viewpoints of the breaking device of figures 1 through 4 with disassembled parts;
Figure 6 shows a schematic view of a screen provided with a second preferred embodiment of a breaking device according to the invention in operational position;
Figure 7 shows a schematic view of the screen of figure 6 with the breaking device in non-operational position;
Figure 8 shows a front view with removed parts of the breaking device of figures 6 and 7 in operational position;
Figure 9 shows a schematic view of the breaking device of figures 6 through 8 with disassembled parts;
Figure 10 shows a schematic view of a screen provided with a third preferred embodiment of a breaking device according to the invention in operational position;
Figure 11 shows a schematic view of the screen of figure 10 with the breaking device in non-operational position;
Figure 12 shows a detailed view of the breaking device of figures 10 and 1 in operational position;
Figure 13 shows the breaking device of figure 12 in non-operational position;
Figures 14A and 14B show schematic views from different viewpoints of the breaking device of figures 10 through 13 with disassembled parts. Figures 1 and 2 show a schematic view of a screen 100, such as a window covering, provided with a breaking device 1 according to a first preferred
embodiment of the invention. In both figures by way of illustration a roller blind system 100 is shown, that is provided with a curtain or cloth 102 that is attached to an elongated housing or rail 103. In the rail 103 lies a rotatable shaft (not shown), that is operational by means of a chain. In the chain the breaking device 1 according to the invention is accommodated. In figure 1 the breaking device 1 assumes an operational position, wherein the user can operate the screen 100 by means of the chain. In figure 2 the breaking device 1 assumes the non-operational position, wherein the breaking device 1 is split in two parts, such that the lower part of the chain is detached from the rail 103. The breaking device 1 according to the invention is arranged such, that the non-operational position is assumed, when the pulling force, exerted by a user on both sides of the chain, reaches or exceeds a predetermined threshold value. This is illustrated by means of the weight 104 that determines the pulling force. A suitable threshold value can be calculated on the basis of a maximum allowable weight of for example 8 kilograms, pulling on both sides of the chain.
Figures 3 and 4 show the breaking device 1 with cut-away parts in the operational, respectively non-operational position. Figures 5A and 5B show the breaking device 1 with disassembled parts from different viewpoints. Breaking device 1 according to the invention comprises a first or lowest housing part 10 and a second or upper housing part 20 that can be coupled in a detachable manner. The first housing part 10 comprises two plate shaped parts 10A and 10B. The second housing part 20 also comprises two plate shaped parts 20A and 20B. The plate shaped parts need to be pair wise attached to each other while clamping various parts, that will be described in more detail herein below.
In the first housing part 10 a first toothed wheel 1 1 and a first sprocket 12 are received, that are connected to each other. In the second housing part 20 a second toothed wheel 21 and a second sprocket 22 are received, that are connected to each other. In the preferred embodiment shown the first toothed wheel 11 and the first sprocket 12 are arranged on opposite sides of a plate shaped element and form an integrated part 13. In the shown preferred embodiment the second toothed wheel 21 and the second sprocket 22 are in a similar way arranged on both sides of a plate shaped element and together form an integrated part 23. Both integrated parts 13, 23 can be manufactured by means of injection moulding. In the first housing part 10 lies a shaft 14 on which the integrated part 13 can be arranged. In the second housing part 20 lies a shaft 24 on which the integrated part 23 can be arranged. In the preferred embodiment shown around the first sprocket 12 a chain 15 is attached and around the second sprocket 22 a chain 25 is attached. The chain 15 serves as an operational chain for the user. The chain 25 is connected to a transmission in the rail 103 for driving the rotatable shaft (not shown) present therein. Suitable transmissions are known in the relevant art.
The integrated parts 13 and 23 engage onto each other by means of an in- between third toothed wheel 31. More specifically this third toothed wheel 31 engages onto the first toothed wheel 11 and onto the second toothed wheel 21.
The third toothed wheel 31 ensures the first toothed wheel 11 together with the first sprocket 12 to follow the same direction of rotation, in this example clockwise, as the second toothed wheel 21 together with the second sprocket 22 during operation of the chain 15 with a pulling force Fi. Consequently the force F2 that is exerted on the second chain 25 lies in the same direction as the force Fi.
The coupling between the first housing part 0 and the second housing part 20 is partly performed as a click connection. The click connection is arranged on one side of the facing circumferential edges of the first housing part 10 and the second housing part 20. The click connection is formed by an elastic lip 42 and a first recess 43 corresponding to the shape of this lip. In the preferred embodiment shown the elastic lip 42 lies on the first housing part 10 and the first recess 43 lies on the second housing part 20. The coupling further comprises a pivotable connection that is arranged on an opposite side of the facing circumferential edges of both the first housing part 10 as well as the second housing part 20. The pivotable connection is formed by a hook-like element 44 and a second recess 45 corresponding to the shape of the hook-like element. In the preferred embodiment shown the hook-like element 44 lies on the first housing part 10 and the second recess 45 lies on the second housing part 20. If so desired these positions of lip 42 and corresponding recess 43 can be interchanged. This is also valid for the positions of the barb 44 and the corresponding recess 45.
The third or in-between toothed wheel 31 lies off-centre in the housing 10, 20 and lies closer to the pivotable connection 44, 45 than to the click connection 42, 43. In the preferred embodiment shown a shaft 34 for the third toothed wheel lies in the housing 10, 20. This shaft 34 preferably lies in the second housing part 20.
The coupling of the breaking device 1 according to the invention should be designed such that the click connection 42, 43 releases earlier, i.e. at a lower pulling force, than the pivotable connection 44, 45.
If a user exerts a pulling force on the first chain 15, this pulling force will be transferred via at least the first sprocket 12, the first toothed wheel 1 1 and the second toothed wheel 22 to the second sprocket 22 and via second chain 25 to the rotatable shaft on which the screen is attached. The coupling is designed such that the breaking device 1 assumes the operational position if the pulling force lies below a predetermined threshold value. If the pulling force at both sides reaches or exceeds the predetermined threshold value, both the click connection and the pivotable connection will open as a consequence whereof the first housing part 10 and the second housing part 20 will decouple.
In the situation that the pulling force approaches the predetermined threshold value, the click connection will release first, but the pivotable connection will be maintained. As the third in-between toothed wheel is arranged close to the pivotable connection, the first toothed wheel 11 and the second toothed wheel 21 will remain in engagement with the third toothed wheel 31 as long as the pivotable connection is maintained. Only when the pulling force actually reaches the predetermined threshold value, the pivotable connection will release due to which the first toothed wheel 11 and the third toothed wheel 31 will disengage. The breaking device 1 then is no longer operational.
At the side of the stronger pivotable or second coupling in the breaking device 1 a preferred side arises, that can carry heavier loads than the opposite side close to the click connection or first coupling. This can be used advantageously by accommodating the breaking device 1 in the chain 15; 25 in such a way that lifting of the screen 100 takes place by exerting a pulling force on that preferred side. The preferred side can withstand heavier loads and will remain operational at higher pulling forces.
Figures 6 and 7 show a schematic view of a screen, such as a window covering 200, provided with a breaking device 101 according to a second preferred embodiment of the invention. In both figures by way of illustration a folding blind system 200 is shown, that is provided with a cloth 202 that is attached by means of cords to an elongated housing or rail 203. In the rail 203 lies a rotatable shaft (not shown), that is operational by means of a chain. The breaking device 1 according to the invention is attached to the elongated housing 203. In figure 6 the breaking device 101 assumes an operational position, wherein the user can operate the screen 200 by means of the chain. In figure 7 the breaking device 101 assumes the non-operational position, wherein the breaking device 101 is split in two parts, such that the lower part of the chain is detached from the rail 203. The breaking device 101 according to the invention is arranged such, that the non-operational position is assumed, when the pulling force, exerted by a user on both sides of the chain, reaches or exceeds a predetermined threshold value. A suitable threshold value can be calculated on the basis of a maximum allowable weight of for example 8 kilograms, pulling on both sides of the chain.
Figure 8 shows the breaking device 101 with cut-away parts in the operational position. Figure 9 shows the breaking device 101 with cut-away parts in the non- operational position. Breaking device 101 according to the invention comprises a first or lowest housing part 110 and a second or upper housing part 120 that can be coupled in a detachable manner. The first housing part 1 10 comprises two plate shaped parts 110A and 110B. The second housing part 120 also comprises two plate shaped parts 120A and 120B. The (plate shaped) parts need to be pair wise attached to each other while clamping various parts, that will be described in more detail herein below.
In the first housing part 110 a first toothed wheel 111 and a first sprocket 112 are received, that are connected to each other. In the second housing part 120 a second toothed wheel 121 is received. In the preferred embodiment shown the first toothed wheel 111 and the first sprocket 112 are arranged on opposite sides of a plate shaped element and form an integrated part 1 13. The integrated part 113 can be manufactured by means of injection moulding.
In the first housing part 110 lies a shaft 114 on which the integrated part 1 13 can be arranged. In the second housing part 120 lies an unround attachment member 124 on which the second toothed wheel 121 can be arranged.
The unround attachment member 124 is fixedly connected to the rotatable shaft (not shown) that can be inserted into holder 205. Suitable holders and attachment members are known in the relevant art.
In the preferred embodiment shown around the first sprocket 112 a chain 15 is attached. The chain 115 serves as an operational chain for the user.
The integrated part 113 and the second toothed wheel 121 engage onto one another by means of an in-between third toothed wheel 131. More specifically this third toothed wheel 131 engages onto the first toothed wheel 111 and onto the second toothed wheel 121. The third toothed wheel 131 ensures the first toothed wheel 111 together with the first sprocket 1 12 to follow the same direction of rotation, in this example clockwise, as the second toothed wheel 121 during operation of the chain 115 with a pulling force
The coupling between the first housing part 110 and the second housing part
120 is partly performed as a click connection. The click connection is arranged on one side of the facing circumferential edges of the first housing part 110 and the second housing part 120.
The click connection is formed by an elastic lip 142 and a first protrusion 143 corresponding to the shape of this lip. In the preferred embodiment shown the elastic lip 1 2 lies on the first housing part 110 and the first protrusion 143 lies on the second housing part 120. The coupling further comprises a pivotable connection that is arranged on an opposite side of the facing circumferential edges of both the first housing part 110 as well as the second housing part 120. The pivotable connection is formed by a hook-like element 144 and a second protrusion 145 corresponding to the shape of the hook-like element. In the preferred embodiment shown the hook-like element 144 lies on the first housing part 110 and the second protrusion 1 5 lies on the second housing part 120. If so desired these positions of lip 1 2 and
corresponding protrusion 143 can be interchanged. This is also valid for the positions of the barb 144 and the corresponding protrusion 145.
The coupling of the breaking device 101 according to the invention should be designed such that the click connection 142, 143 releases earlier, i.e. at a lower pulling force, than the pivotable connection 144, 145.
If a user exerts a pulling force on the first chain 115, this pulling force will be transferred via at least the first sprocket 112, the first toothed wheel 1 11 and the second toothed wheel 121 to the rotatable shaft on which the screen is attached. The coupling is designed such that the breaking device 101 assumes the operational position if the pulling force lies under a predetermined threshold value. If the pulling force at both sides reaches or exceeds the predetermined threshold value, both the click connection and the pivotable connection will open as a consequence whereof the first housing part 1 10 and the second housing part 120 will decouple.
In the situation that the pulling force approaches the predetermined threshold value, the click connection will release first, but the pivotable connection be maintained. Since the first housing part 1 10 is attached to the fixed world by means of the rail 203, the first toothed wheel 111 and the second toothed wheel 121 will remain in engagement with the third toothed wheel 31 as long as the pivotable connection is maintained. Only when the pulling force actually reaches the predetermined threshold value, the pivotable connection will release due to which the first toothed wheel 111 and the second wheel 131 will disengage. The breaking device 101 is then no longer operational.
Also in the breaking device 101 a preferred side arises at the side of the stronger pivotable or second coupling that can carry heavier loads than the opposite side close to the click coupling or first coupling. This can be used advantageously by attaching the breaking device 101 to the rail 203 in such a way that lifting of the screen 200 takes place by exerting a pulling force on that preferred side. The preferred side can withstand heavier loads and will remain operational at higher pulling forces.
Figures 10 and 1 show a schematic view of the screen 100 of figures 1 and 2 provided with a breaking device 201 according to a third preferred embodiment of the invention. In the chain the breaking device 201 according to the invention is accommodated. In figure 10 the breaking device 201 assumes an operational position, wherein the user can operate the screen 100 by means of the chain. In figure 11 the breaking device 201 assumes the non-operational position, wherein the breaking device 201 is split in two parts, such that the lower part of the chain is detached from the rail 103. The breaking device 201 according to the invention is arranged such, that the non-operational position is assumed, when the pulling force, exerted by a user on both sides of the chain, reaches or exceeds a predetermined threshold value. This is illustrated by means of the weight 104 that determines the pulling force. A suitable threshold value can be calculated on the basis of a maximum allowable weight of for example 8 kilograms, pulling on both sides of the chain.
Figures 12 and 13 show the breaking device 201 with cut-away parts in the operational, respectively non-operational position. Figures 14A and 14B show the breaking device 201 with disassembled parts from different viewpoints. Breaking device 201 according to the invention comprises a first or lowest housing part 210 and a second or upper housing part 220 that can be coupled in a detachable manner. The first housing part 210 comprises two plate shaped parts 210A and 210B. The second housing part 220 also comprises two plate shaped parts 220A and 220B. The plate shaped parts need to be pair wise attached to each other while clamping various parts, that will be closer described herein below.
In the first housing part 210 a first toothed wheel 21 and a first sprocket 212 are received, that are connected to each other. In the second housing part 220 a second toothed wheel 221 and a second sprocket 222 are received, that are connected to each other. In the preferred embodiment shown the first toothed wheel 211 and the first sprocket 212 are arranged on opposite sides of a plate shaped element and form an integrated part 213. In the shown preferred embodiment the second toothed wheel 221 and the second sprocket 222 are in a similar way arranged on both sides of a plate shaped element and together form an integrated part 223. Both integrated parts 213, 223 can be manufactured by means of injection moulding.
In the first housing part 210 lies a shaft 214 on which the integrated part 213 can be arranged. In the second housing part 220 lies a shaft 224 on which the integrated part 223 can be arranged. In the preferred embodiment shown around the first sprocket 212 a chain 215 is attached and around the second sprocket 222 a chain 225 is attached. The chain 215 serves as an operational chain for the user. The chain 225 is connected to a transmission in the rail 103 for driving the rotatable shaft (not shown) present therein. Suitable transmissions are known in the relevant art.
The integrated parts 2 3 and 223 engage onto one another by means of an in- between third toothed wheel 231. More specifically this third toothed wheel 231 engages onto the first toothed wheel 211 and onto the second toothed wheel 221.
The third toothed wheel 231 ensures the first toothed wheel 211 together with the first sprocket 212 to follow the same direction of rotation, in this example clockwise, as the second toothed wheel 221 together with the second sprocket 222 during operation of the chain 215 with a pulling force Fi . Consequently the force F2 that is exerted on the second chain 225 lies in the same direction as the force
The coupling between the first housing part 210 and the second housing part 220 is partly performed as a click connection. The click connection is arranged on one side of the facing circumferential edges of the first housing part 210 and the second housing part 220.
The click connection is formed by an elastic lip 242 and a first recess 243 corresponding to the shape of this lip. In the preferred embodiment shown the elastic lip 242 lies on the first housing part 210 and the first recess 243 lies on the second housing part 220. In the preferred embodiment shown the lip comprises two parts: 242A and 242B.
The coupling further comprises a sliding connection. The sliding connection is formed by a rib 244 and a groove 245 corresponding to the shape of the rib. The rib can be slid into the groove in a sliding direction S under an angle a with the direction F1 , wherein a≠0.
The sliding connection is form-fitting, such that the sliding connection is maintained when a force perpendicular to the sliding direction S. In the preferred embodiment shown the rib 244 lies on the first housing part 210 and the second groove 245 lies on the second housing part 220. If so desired these positions of lip 242 and corresponding recess 243 can be interchanged. This is also valid for the positions of the rib 244 and the corresponding groove 245.
The sliding connection is arranged on facing second circumferential edges of the first housing part 210 and the second housing part 220. The first and second circumferential edges are under an angle β, wherein 0 < β < 180 degrees.
The third or in-between toothed wheel 231 lies in the centre in the housing 210, 220. In the preferred embodiment shown a shaft 234 for the third toothed wheel lies in the housing 210, 220. This shaft 234 preferably lies in the second housing part 220.
At the side of the sliding or second coupling in the breaking device 201 a preferred side arises, that can carry heavier loads than the opposite side close to the click coupling or first coupling. This can be used advantageously by accommodating the breaking device 201 in the chain 215; 225 in such a way that lifting of the screen 100 takes place by exerting a pulling force on the part of the chain extending along that preferred side. The preferred side can withstand heavier loads and will always remain operational at higher pulling forces.
The coupling of the breaking device 201 according to the invention should be designed such that the click connection 242, 243 releases when the pulling force, that a user essentially exerts simultaneously on both sides of the chain reaches or exceeds a predetermined threshold value.
During operation the breaking device 201 will remain hanging right due to the third toothed wheel 231 that makes sure the forces F1 and F2 lie in line.
If a user exerts a pulling force on the first chain 215, this pulling force will be transferred via at least the first sprocket 212, the first toothed wheel 21 and the second toothed wheel 222 to the second sprocket 222 and via second chain 225 to the rotatable shaft on which the screen is attached. The coupling is designed such that the breaking device 201 assumes the operational position as long as the pulling force F1 exerted on the part of the chain extending along the non-preferred side lies under a predetermined threshold value. If the pulling force at both sides of the chain simultaneously reaches or exceeds the predetermined threshold value, the click connection and consequently the sliding connection will open as a consequence whereof the first housing part 210 and the second housing part 220 will decouple. This is illustrated by means of F1 , the reaction force between the toothed wheels (not shown) and the resulting force FR perpendicular to the sliding direction S. The form- fitting sliding connection will then be maintained.
The present invention is not limited to the embodiments shown and described. The invention also extends to all combinations of the shown and described embodiments and especially to the combination of the second and the third embodiment. In the second, fixed embodiment the click coupling (142, 143) and the pivotable coupling (144, 145) can surely also be replaced by the click coupling (242, 243) and the sliding coupling (244, 245) of the third, free hanging embodiment.
Furthermore in the figures a transmission formed by three toothed wheels is shown, since this is the most practical embodiment. A person skilled in the art will immediately understand that the invention is not limited to the application of toothed wheels, but that the invention can also be realized by means of all other wheels that can be brought into engagement with each other. In the figures furthermore a compact design is shown, wherein the third toothed wheel has a smaller diameter than the first and second toothed wheel. This is however not necessary for application of the inventive idea. A person skilled in the art will be able to design a functional transmission on the basis of three engaging wheels for a breaking device according to the invention after reading the text. Consequently the invention extends to all embodiments falling under the appending claims, whereby the figures serve as explanation.

Claims

1. Breaking device for a chain of a screen, such as a window covering,
comprising:
- a housing formed by a first housing part and a second housing part, that are attachable to each other by a detachable coupling,
- a first sprocket and a first toothed wheel, that are connected to each other and are arranged in the first housing part, wherein a first chain engages on the first sprocket,
- a second toothed wheel, that is arranged in the second housing part, wherein the breaking device is arranged to transfer a pulling force on one side of the chain, via at least the first sprocket, the first toothed wheel and the second toothed wheel, to a rotatable shaft on which the screen is attached, wherein the coupling between the first housing part and the second housing part releases when the pulling force at both sides of the chain reaches or exceeds a predetermined threshold value, wherein the breaking device further comprises a third toothed wheel, that brings the first toothed wheel in engagement with the second toothed wheel, wherein the detachable coupling comprises a first coupling and a second coupling, characterized in that, the first coupling (42, 43; 142, 143; 242, 243) and the second coupling (44, 45; 144, 145; 244, 245) are arranged such that near the second coupling a preferred side is defined for operation of the lifting of the screen, whereby higher pulling forces are possible at the part of the chain that extends near the preferred side, without the coupling releasing, than at the part of the chain that extends near a non-preferred side, which non-preferred side lies near the first coupling.
Breaking device according to claim 1 , wherein the second coupling comprises a sliding connection (244, 245) having a sliding direction (S) under an angle a with the direction (F1 ) in which the pulling force is exerted, wherein a≠0.
Breaking device according to claim 2, wherein the sliding connection (244, 245) is form-fitting.
Breaking device according to claims 2 or 3, wherein the sliding connection comprises a cooperating rib (244) and groove (245).
5. Breaking device according to claims 2, 3 or 4, wherein a is chosen such that the resulting force (FR ) due to exerting the pulling force (F1) on the chain part extending near the preferred side lies substantially perpendicular to the sliding direction (S).
6. Breaking device according to claim 1 , wherein the second coupling is a
pivotable coupling (44, 45; 144, 145), which second coupling releases at a pulling force equal to or greater than the predetermined threshold value, wherein the first coupling (42, 43; 142, 143) releases at a lower pulling force than the second coupling and wherein the third toothed wheel (31 ; 131) is arranged closer to the second coupling than to the first coupling.
7. Breaking device according to claim 6, wherein the first (42, 43; 142, 143) and the second (44, 45; 144, 145) coupling lie opposite.
8. Breaking device according to one of the preceding claims, wherein the first coupling comprises a click coupling (42, 43; 142, 143; 242, 243). 9. Breaking device according to one of the preceding claims, wherein the first (10; 110; 210) and the second housing part (20; 120; 220) are provided with the first and the second coupling at facing circumferential edges.
Breaking device according to one of the preceding claims, wherein the second housing part (20; 220) comprises a second sprocket (22; 222), that is connected to the second toothed wheel (21; 221), wherein a second chain (25; 225) can engage around the second sprocket.
Breaking device according to one of the preceding claims, wherein the second housing part (120) is arranged for attachment to an elongated housing of the screen, in which the rotatable shaft lies, such that the second toothed wheel (121) drives the rotatable shaft.
12. Breaking device according to one of the preceding claims, wherein the third toothed wheel (31; 131 ; 231) is arranged in the second housing part (20; 120; 220).
PCT/NL2012/050160 2011-03-16 2012-03-15 Safety coupling for a roller screen tension cord WO2012125036A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
NL2006404A NL2006404C2 (en) 2011-03-16 2011-03-16 DISCHARGE DEVICE FOR A NECKLACE OF A SCREEN, SUCH AS A WINDOW COVER.
NL2006404 2011-03-16
NL2008036 2011-12-23
NL2008036A NL2008036C2 (en) 2011-03-16 2011-12-23 DISCHARGE DEVICE FOR A NECKLACE OF A SCREEN, SUCH AS A WINDOW COVER.

Publications (1)

Publication Number Publication Date
WO2012125036A1 true WO2012125036A1 (en) 2012-09-20

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PCT/NL2012/050160 WO2012125036A1 (en) 2011-03-16 2012-03-15 Safety coupling for a roller screen tension cord

Country Status (2)

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NL (1) NL2008036C2 (en)
WO (1) WO2012125036A1 (en)

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