Tent – canopy – umbrella – or cane – Umbrella – Collapsible in length
Reexamination Certificate
2000-06-28
2002-07-16
Stodola, Daniel P. (Department: 3634)
Tent, canopy, umbrella, or cane
Umbrella
Collapsible in length
C135S025330, C135S075000, C403S341000
Reexamination Certificate
active
06418949
ABSTRACT:
BACKGROUND OF THE INVENTION
U.S. Pat. No. 6,035,873 issued to the same inventors of this application disclosed a multiple-fold umbrella having gradationally convex telescopic shaft consisting of five or four tubes telescopically engageable with one another. However, there is a large sliding contact area between an outer tube and a corresponding or neighboring inner tube engageable with the outer tube, thereby influencing a smooth folding on unfolding operation of the central shaft when closing or opening the umbrella due to frictional contact between the outer and inner tubes.
The present inventor has found the drawback of the prior patent and invented the present umbrella shaft for a more smooth folding and unfolding operation.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a multiple-fold umbrella shaft, consisting of a plurality of tubes telescopically engageable with one another, including an inner tube having concave quadrants designated as Vi, and an outer tube slidably engageable with the inner tube and having concave quadrants designated as Vo, forming a relationship as defined by a formula of Vi−Vo≧1 in order for preventing twisting and vibration of the tubes and for enhancing a smooth folding or unfolding operation when closing or opening the umbrella.
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Chang Jung-Jen
Lin Chung-Kuang
Fu Tai Umbrella Works Ltd.
Stodola Daniel P.
Tran Khoa
Troxell Law Office PLLC
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