Contraction structure of center post of self-opening umbrella

Abstract

A contraction structure of center post of self-opening umbrella includes an outer tube and an intermediate tube telescopically fit to each other. The intermediate tube has an upper end to which an outer tube plug is mounted. The center post receives therein two sections of runner cord. The two sections of runner cord each have an end fixed to the outer tube plug and an opposite end extending around a runner cord pulley mounted to an upper end of the center post and fixed to a runner at a first runner-cord fixed position. The present invention applies two sections of runner cord to simultaneously operate so that in withdrawing the runner, two identical pulling forces are applied to the runner to enable smooth withdrawal of the runner. The present invention reduces the number of pulleys used, simplifies the structure, and improves the liability of the umbrella and extends lifespan.

1 . contraction structure of a center post of a self-opening umbrella, characterized in that the contraction structure of the center post comprises: an outer tube ( 1 ) and an intermediate tube ( 2 ) telescopically fit to each other, and an inner tube ( 3 ) telescopically received in the intermediate tube ( 2 ), the intermediate tube ( 2 ) having an upper end to which an outer tube plug ( 13 ) is mounted, the center post receiving therein two sections of runner cord ( 11 ), the two sections of runner cord ( 11 ) each having an end fixed to the outer tube plug ( 13 ) and an opposite end extending around a runner cord pulley ( 24 ) mounted to an upper end of the center post and fixed to a runner ( 5 ) at a first runner-cord fixed position ( 25 ), an internal spring ( 15 ) being received in the center post and having an end supported on the outer tube plug ( 13 ) and an opposite end supported on a lower end of the inner tube ( 3 ) so that the internal spring ( 15 ) elastically biases the outer tube plug ( 13 ) away from the lower end of the inner tube ( 3 ) in such a way that the biasing force of the internal spring ( 15 ) holds the outer tube ( 1 ) in an expanded position with respect to the intermediate tube ( 2 ) by stretching an outer tube cord ( 12 ) having ends respectively fixed to the outer tube ( 1 ) and a bullet ( 10 ) releasably retained at the lower end of the inner tub ( 3 ). 
     
     
         2 . The contraction structure of center post of self-opening umbrella according to  claim 1 , characterized in that the outer tube plug ( 13 ) has second runner-cord fixed positions ( 19 ) and the two sections of runner cord ( 11 ) are respectively connected to the second runner-cord fixed positions ( 19 ). 
     
     
         3 . The contraction structure of center post of self-opening umbrella according to  claim 1 , characterized in that the outer tube plug ( 13 ) comprises a direction-change bar ( 26 ) fixed thereto, the two sections of runner cord ( 11 ) being jointed to each other at the direction-change bar ( 26 ).