# US 2017/0145744 A1 · Child safe operating wand for a blind > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0145744 A1 - Document ID: US20170145744A1 - Status: Published application - Kind: A1 - Application number: 15/316,678 - Filed: 2015-06-05 - Published: 2017-05-25 - Earliest claimed: 2014-06-06 - Assignees: Fourds Limited - Applicants: Fourds Limited - Inventors: Cormac DIAMOND - Web page: https://patentgrep.com/patent/US20170145744A1 ## CPC - E06B 9/78: for direct manual operation, e.g. by tassels, by handles - E06B 9/322: Details of operating devices, e.g. pulleys, brakes, spring drums, drives ({operating devices E06B9/68} ; devices of general interest specially adapted or mounted for storing and repeatedly paying-out and re-storing lengths of material B65H75/34) - E06B 9/326: Details of cords, e.g. buckles, drawing knobs - E06B 9/42: Parts or details of roller blinds, e.g. suspension devices, blind boxes (brackets or adjustable mountings for roller blinds and drawable curtains A47H1/13) - F16H 19/0645: {the flexible push or pull member having guiding means, i.e. the flexible member being supported at least partially by a guide to transmit the reciprocating movement (the flexible member being a non-buckling chain F16H19/0636)} - F16H 25/18: for conveying or interconverting oscillating or reciprocating motions - F16H 31/001: {Mechanisms with freewheeling members} - F16H 57/035: Gearboxes for gearing with endless flexible members - E06B 2009/3222: {Cordless, i.e. user interface without cords} - F16H 2019/0681: {the flexible member forming a closed loop} - E06B: FIXED OR MOVABLE CLOSURES FOR OPENINGS IN BUILDINGS, VEHICLES, FENCES OR LIKE ENCLOSURES IN GENERAL, e.g. DOORS, WINDOWS, BLINDS, GATES (shades or blinds for greenhouses A01G9/22; curtains A47H; lids for car boots or bonnets B62D25/10; skylights E04B7/18; sunshades, awnings E04F10/00) - F16H: GEARING ## Abstract An operating mechanism is provided for a screen assembly having an elongate endless pull cord hanging from the screen assembly in a loop. The operating mechanism has a housing having an opening at an upper end thereof. At least a lower portion of the pull cord can pass into the housing to be enclosed therein. A guide means for guiding passage of the pull cord through the housing. The guide means has a locking means adapted to selectively restrain first or second sides of a loop defined by the pull cord. The guide means includes a cord-retaining member engaging a lower end of the looped pull cord. The cord-retaining member is moveable within the housing between vertically spaced first and second positions, the second position being above the first position, the cord-retaining member being biased towards the first position by biasing means. The housing may be displaced downwardly with respect to the pull cord by upward movement of the cord-retaining member between the positions against the force of the biasing means. ## Claims ### Claim 1 An operating mechanism for a screen assembly of the type having an elongate endless pull cord hanging from the screen assembly in a loop, said operating mechanism comprising a housing having an opening at an upper end whereby at least a lower portion of the pull cord can pass into the housing to be enclosed therein, the housing incorporating guide means for guiding passage of the pull cord through the housing, said guide means incorporating locking means adapted to selectively restrain the first or second side of a loop defined by the pull cord within the housing as the housing is pulled downwardly with respect to the screen assembly, said guide means comprising a first sprocket rotatably mounted within the housing adapted to engage a first portion of the pull cord on a first side of the loop defined thereby and a second sprocket rotatably mounted within the housing adapted to engage a second portion of the pull cord on a second side of the loop defined thereby, the locking means being adjustably configurable between a first state, wherein the locking means prevents rotation of the first sprocket as the housing is displaced downwardly with respect to the pull cord, causing the housing to pull on said first side of the loop defined by the pull cord, and a second state, wherein the locking means prevents rotation of the second sprocket as the housing is displaced downwardly with respect to the pull cord, causing the housing to pull on the second side of the loop defined by the pull cord, wherein the guide means includes a cord retaining member engaging a lower end of the looped pull cord, said cord retaining member being moveable within the housing between vertically spaced first and second positions, said second position being above said first position, the cord retaining member being biased towards said first position by biasing means, whereby the housing may be displaced downwardly with respect to the pull cord by virtue of upward movement of the cord retaining member between its first and second positions within the housing against the force of the biasing means. ### Claim 2 (canceled) ### Claim 3 (depends on 1) An operating mechanism as claimed in claim 1, wherein said cord retaining member comprises a pulley around which the lower end of the loop defined by the cord passes. ### Claim 4 (depends on 1) An operating mechanism as claimed in claim 1, wherein said cord retaining member comprises a loop or hook engaging a lower end of the loop defined by the cord. ### Claim 5 (depends on 3) An operating mechanism as claimed in claim 3, wherein said biasing means comprises an elongate elastic member, said cord retaining member being attached to or being defined by a free end of said elongate elastic member. ### Claim 6 (depends on 5) An operating mechanism as claimed in claim 5, wherein said elongate elastic member comprises a tension spring, compression spring or an elastic band. ### Claim 7 (depends on 1) An operating mechanism as claimed in claim 1, wherein said housing comprises an upper part and a lower part, said lower part being rotatable with respect to said upper part in order to adjust the locking means between its first and second states. ### Claim 8 (depends on 7) An operating mechanism as claimed in claim 7, within which said first and second sprockets and said locking means are housed within the upper part of the housing and said pull cord retaining member and biasing means are housed within said lower part of the housing. ### Claim 9 (depends on 7) An operating system as claimed in claim 7, wherein the upper part of the housing is adapted to engage the screen assembly such that a twisting torque applied to the lower part of the housing can be transferred to the screen assembly in order to facilitate control of the locking means. ### Claim 10 (depends on 1) An operating mechanism as claimed in claim 1, wherein said first and second sprockets are arranged coaxially in side by side relationship within the housing. ### Claim 11 (depends on 1) An operating mechanism as claimed in claim 1, wherein the first portion of the pull cord passes around the first sprocket from a first side of the housing to a second side of the housing, said second portion of the pull cord passing around the second sprocket from the second side of the housing to the first side of the housing. ### Claim 12 (depends on 1) An operating mechanism as claimed in claim 1, wherein each of said first and seconds sprockets is provided a guide channel provided around the outer periphery thereof for receiving said pull cord therein. ### Claim 13 (depends on 12) An operating mechanism as claimed in claim 12, wherein said guide channel of each sprocket is provided with circumferentially arranged formations to grip the pull cord. ### Claim 14 (depends on 1) An operating mechanism as claimed in claim 1, wherein said locking means is arranged to selectively engage teeth provided around each of said first and second sprockets. ### Claim 15 (depends on 14) An operating mechanism as claimed in claim 14, wherein the locking means comprises respective latching members, each latching member having a head portion adapted to engage the teeth of a respective one of the first and second sprockets when in a latching position. ### Claim 16 (depends on 15) An operating mechanism as claimed in claim 15, wherein the head portion of each latching member is shaped to engage a lower side of a respective tooth of the respective sprocket. ### Claim 17 (depends on 15) An operating mechanism as claimed in claim 15, wherein each latching member is moveable between a first position, wherein the head portion of the respective latching member engages the teeth of the respective sprocket, and a second position, wherein the head portion of the respective latching member is spaced from the respective sprocket, each latching member being resiliently biased towards its first position by a biasing means. ### Claim 18 (depends on 17) An operating mechanism as claimed in claim 17, wherein each latching member is arranged such that rotation of the respective sprocket in a first direction is prevented by the abutment of the latching member with the teeth of the respective sprocket while rotation of the respective sprocket in a second, opposite direction causes the teeth of the sprocket to displace the latching member outwardly with respect to the sprocket against the force of said biasing means, allowing rotation of the respective sprocket in said second direction. ### Claim 19 (depends on 1) An operating system as claimed in claim 1, wherein shock absorbing or damping means are provided for slowing movement of the cord retaining member as it approaches its first position under the action of the biasing means in order to prevent forceful impact of the housing with the screen assembly. ### Claim 20 (canceled)