Twist release safety stop ball for window covering cord

1. A safety stop ball for use in window coverings, comprising:

a post;

a nut;

thread means defining a spiral path along which said nut travels relative to said post from an engaged position, in which said post and nut cooperate to form at least one retaining cavity for receiving and retaining an enlarged lift cord end, to a released position, wherein said post and nut are moved apart from each other to release the lift cord end.

2. A safety stop ball for use in window coverings as recited in claim 1 , wherein said post defines a plurality of first cavities, said nut defines a plurality of second cavities, and, in said engaged position, said first and second cavities are aligned to form a plurality of retaining cavities.

3. A safety stop ball for use in window coverings as recited in claim 2 , and further comprising a biasing means biasing said nut toward said engaged position.

4. A safety stop ball for use in window coverings as recited in claim 3 , and further comprising a housing and a lid, said housing having a substantially open top which receives said lid, and a substantially closed bottom, wherein said post is fixed relative to said housing and said nut is movably received in said housing, and wherein said lid engages said nut such that pushing said lid inwardly into said housing pushes the nut toward the released position.

5. A safety stop ball for use in window coverings as recited in claim 4 , wherein said biasing means is a spring substantially contained within said housing between the bottom of said housing and said nut.

6. A safety stop ball for use in window coverings as recited in claim 4 , wherein said biasing means is a spring extending between the post and the nut.

7. A safety stop ball for use in window coverings as recited in claim 4 , wherein said thread means includes male threads on said post and mating female threads on said nut.

8. A safety stop ball for use in window coverings as recited in claim 7 , wherein said lid defines a plurality of through openings for receiving lift cords from the window covering.

9. A safety stop ball for use in window coverings as recited in claim 8 , and further comprising a plurality of lift cords extending from said window covering, each of said lift cords extending through its respective through opening in said lid and having an enlarged end received in a respective retaining cavity such that, when said nut is in the engaged position, the lift cord ends are retained in their respective retaining cavities, and wherein, when the lid pushes the nut to the released position, the lift cord ends are released and pass out through said through openings.

10. A safety stop ball for use in window coverings as recited in claim 9 , and further comprising a fixed lift cord permanently secured relative to said post.

11. A safety stop ball for use in window coverings, comprising:

a housing having a substantially open top and having a bottom;

a lid movably received in said open top, said lid defining a plurality of through openings;

a post fixed to the housing and extending downwardly into said housing;

a nut received in said housing, said post and nut having mating spiral threads defining a spiral path along which said nut travels from an upper, engaged position in which said nut and post cooperate to form at least one retaining cavity, to a lower, released position;

a biasing means biasing said nut toward the upper, engaged position;

at least two lift cords, each extending through its respective through opening in said lid; at least one of said lift cords having an enlarged end received in said at least one retaining cavity;

wherein said lid engages said nut such that, when said lid is pushed inwardly into said housing, it pushes said nut to said released position, releasing the enlarged lift cord end from its retaining cavity and allowing said enlarged lift cord end to pass out through its respective through opening in said lid.