An automatic umbrella includes: a central shaft (1) having a lower tube (11), a middle tube (13) and an upper tube (14) telescopically engageable with one another, an umbrella rib assembly (2) pivotally secured to the central shaft (1) and having an umbrella cloth (C) secured on the rib assembly (2), an opening spring (3) retained in the central shaft (1) for automatically opening the umbrella, a drag means (4) provided in the central shaft (1) through a lower runner (24) of the rib assembly (2) for pulling the lower runner (24) upwardly for extending the rib assembly (2) when opening the umbrella, and a control means (5) for controlling the automatic opening of the umbrella, wherein the tubes of the central shaft (1) are each made of light weight materials for lightening the weight of the umbrella and each tube having a cross section of concave hexagonal sides for reinforcing the strength of the tubes of the central shaft for a reliable umbrella opening operation.

BACKGROUND OF THE INVENTION 
A conventional automatic umbrella having triple folds as shown in FIG. 1 
includes: a lower tube T1, a middle tube T2 and an upper tube T3 
telescopically engageable with one another to form a central shaft; an 
umbrella rib asssembly R pivotally secured to the central shaft and 
secured to a lower runner L and a middle runner M; an upper spring S1 and 
a lower spring S2 retained in the central shaft for extending the tubes 
T3, T2, T1 when opening the umbrella; a tension spring S3 retained between 
the lower runner L and the middle runner M for extending the rib assembly 
R for opening the umbrella; and a button B slidably held in a grip and 
depressed for opening the umbrella by disengaging the hook H from the 
middle and upper tubes T2, T3 as previously folded on the lower tube T1 
when the umbrella was closed. 
However, such a conventional triple-fold automatic umbrella has the 
following drawbacks: 
1. The elastic force of the springs S1, S2 in the central shaft is very 
strong to rapidly extend the tubes T3, T2, T1, even faster than the 
extending of the rib assembly R as urged by the tension spring S3, to 
possibly injure the umbrella user. 
2. The strong force of the springs S1, S2 may damage the joints of the 
tubes having spring catches C1, C2 provided respectively at the joints. 
3. For connecting or retaining the upper spring S1 and the lower spring S2 
within the central shaft, a plug P and a retainer U should be provided 
between the two springs S1, S2 adjacent to the catch C2, thereby 
increasing the assembly complexity and production inconvenience when 
making the umbrella. 
4. In order to sustain the great spring force of the springs S1, S2, the 
tubes T3, T2, T1 should be made of thick steel tubes to increase the 
umbrella weight and cause carrying inconvenience. If the steel tubes are 
inferentially replaced by light aluminum alloy, the aluminum tubes will be 
easily deformed, twisted or even broken to damage the umbrella. 
The, present inventor has found the drawbacks of the conventional automatic 
umbrella and invented the present automatic umbrella with a light weight 
and reliable operation. 
SUMMARY OF THE INVENTION 
The object of the present invention is to provide a lightening 
multiple-fold automatic umbrella including: a central shaft having a lower 
tube, a middle tube and an upper tube telescopically engageable with one 
another, an umbrella rib assembly pivotally secured to the central shaft 
and having an umbrella cloth secured on the rib assembly, an opening 
spring retained in the central shaft for automatically opening the 
umbrella, a drag means provided in the central shaft through a lower 
runner of the rib assembly for pulling the lower runner upwardly for 
extending the rib assembly when opening the umbrella, and a control means 
for controlling the automatic opening of the umbrella, wherein the tubes 
of the central shaft are each made of light weight materials such as 
aluminum alloy for lightening the weight of the umbrella and each tube 
having a cross section of concave hexagonal sides for reinforcing the 
strength of the tubes of the central shaft for a reliable umbrella opening 
operation.

DETAILED DESCRIPTION 
As shown in FIGS. 2-14, the present invention comprises: a central shaft 1, 
an umbrella rib assembly 2, an opening spring 3, a drag means 4, and a 
control means 5. 
The present invention may be provided for triple folds automatic umbrella. 
Naturally, the present invention may also be used for two-folds umbrella, 
not limited in the present invention. 
The central shaft 1 includes: a lower tube 11 having a grip 12 secured 
under the lower tube 11, a middle tube 13 telescopically engaged with the 
lower tube 11, an upper tube 14 telescopically engaged with the middle 
tube 13, and an inner block 15 fixed in an upper end portion of the upper 
tube 14. 
The middle tube 13 especially as shown in FIG. 5 has a cross section of 
concave hexagonal sides 130, having a lower tube portion of the middle 
tube 13 slidably engageable with an upper tube end 112 of the lower tube 
11 and having a cross section of concave hexagonal sides, and having a 
lowermost tube end 132 of the middle tube 13 contracted to form a 
cylindrical tube 132 to be engageable with the lower tube 11 having a 
cross section of circular shape below the upper tube end 112, and having 
an upper tube end 133 of the middle tube 13 slightly enlarged to form a 
cylindrical tube to be slidably engageable with the upper tube 14. 
The upper tube 14 has a lower tube end 142 having a cross section of 
concave hexagonal sides to be slidably engageable with an upper tube 
portion of the middle tube 13 having a cross section of concave hexagonal 
sides, having an engaging hole 141 formed in the lower tube end 142, and 
having an upper end 143 of the upper tube 14 secured with an upper notch 
22 of the umbrella rib assembly 2. 
The umbrella rib assembly 2 includes: at least a top rib 21 pivotally 
secured to the upper notch 22, a stretcher rib 23 pivotally connected 
between the top rib 21 and a lower runner 24 slidably held on the central 
shaft 1, a middle rib 25 having an inner rib end connected to the 
stretcher rib 23 by means of a middle connecting rib 26 and also pivotally 
connected to the top rib 21 and having an outer rib end of the middle rib 
25 pivotally connected with an outer rib 27 which is also connected to the 
top rib 21 by means of a resilient rib 28. The rib assembly 2 is provided 
for fixing an umbrella cloth C thereon and may be modified for any 
multiple-fold umbrellas. 
The lower runner 24 as shown in FIG. 12 includes: a short sleeve 24 
slidably held on the central shaft 1, a skirt portion 241 gradationally 
enlarged outwardly downwardly from the short sleeve 24 for pulling the 
skirt portion 241 downwardly when closing the umbrella, a socket 242 
recessed in a middle portion of the lower runner 24 for embedding a roller 
holder 451 in the socket 242 for rotatably mounting a lower roller 45 in 
the roller holder 451, and a rope groove 243 longitudinally formed in the 
lower runner 24 for passing a rope 43 of the drag means 4 through the rope 
groove 243 to be wound on the lower roller 45 on the roller holder 451. 
The opening spring 3 is a single elongate spring having a lower spring end 
31 retained in a lower tube portion of the lower tube 11 and having an 
upper spring end 32 retained against the inner block 15 at the upper end 
portion of the upper tube 14. 
The tubes of the central shaft 1 may also be formed as hexagonal shape. The 
designation of this invention as "automatic" umbrella is due to an 
automatic opening of the umbrella by the opening spring 3. For closing the 
umbrella it should be manually done such as by lowering the runner 24 for 
retracting the ribs 2 and folding the tubes by the user. Hence, it is 
critically a semi-automatic umbrella. 
The drag means 4 includes: a link 41 having a lower link end 411 secured on 
a link holder 42 fixed in a lower portion of the lower tube 11, a rope 43 
having a lower rope end 431 connected with an upper link end 412 of the 
link 41 and having an upper rope end 432 fixed into the inner block 15 on 
the upper tube 14 by winding the rope 43 through an upper roller 44 
rotatably mounted on the inner block 15 and then deflected downwardly to 
be wound on the lower roller 45 rotatably mounted on the lower runner 24 
and then to be terminated at the upper rope end 432, a middle sleeve 46 
having a lower sleeve end 461 disposed around a joint between the upper 
link end 412 of the link 41 and the lower rope end 431 of the rope 43 when 
opening the umbrella as shown in FIG. 2, and an upper sleeve 47 having a 
lower sleeve end 471 slidably disposed around an upper sleeve end 462 of 
the middle sleeve 46 and an upper sleeve end 472 of the upper sleeve 47 
connected with the inner block 15; the middle sleeve 46 and the upper 
sleeve 47 being slidably disposed within the opening spring 3. 
The link holder 42 especially as shown in FIGS. 2, 7, 8, 9, 10 and 11 
includes: a plug 421 made of elastomers such as polyvinyl choride, rubber, 
etc., secured on a lower link end 411 of the link 41 by a pin 422, and a 
washer 423 made of rigid materials such as steel or other rigid metals for 
reinforcing the strength of the plug 421. 
The link holder 42 is fixed in a lower tube portion of the lower tube 11 by 
pressing the lower tube 11 inwardly to form at least a pair of lugs 110 
retaining the plug 421 in the lower tube 11 (FIGS. 7, 8) or by inserting 
the pin 422 transversely through the lower tube 11 (FIG. 9). 
When connecting the link 41 with the link holder 42, the lower link end 411 
is flattened to pass through a central hole formed in the washer 423 to be 
inserted into the plug 421 and be fixed with the plug 421 by transversely 
inserting the pin 422 through the plug 421 and the lower link end 411, 
with the link holder 42 fixed in the lower portion of the lower tube 11. 
The roller holder 451 for rotatably mounting the lower roller 45 thereon as 
shown in FIGS. 12-14 includes: a roller shaft 452 protruding inwardly from 
the roller holder 451 which is embedded into the socket 242 recessed in 
the lower runner 24, and at least a tenon 453 engaged in the tenon cavity 
242a in the lower runner (FIG. 14 showing two tenons 453,454 respectively 
engaged with two tenon cavities 242a, 242b formed in the runner 24) for 
embedding the roller holder 451 into the socket 242 in the lower runner 
24. 
The control means 5 includes: a push button 51 slidably held in a button 
hole formed in the grip 12 and having a protrusion 511 extending inwardly 
from the button 51, a control lever 52 pivotally mounted in the grip 12 by 
a pivot 521, a depression portion 522 formed on a middle portion of the 
lever 52 to be depressed by the protursion 511 of the button 51, a hook 
portion 523 formed on an upper end of the lever 52 for engaging the 
engaging holes 131, 141 respectively formed in the middle and upper tubes 
13, 14 when closing the umbrella, and a restoring spring 524 retained in 
the grip 12 and normally urging the hook portion 523 outwardly beyond the 
lower tube 11 ready for engaging the engaging holes 131, 141 of the middle 
and upper tubes 13, 14 when closing the umbrella. 
The link holder 42a as modified in FIG. 15 includes: a cylindrical plug 
421a secured in a lower tube portion of the lower tube 11 by a pin 422, a 
vertical socket 424 longitudinally formed in the plug 421a for engaging a 
locking head 411a secured to the lower link end 411 of the link 41, and an 
elastic pawl 425 pressed inwardly from the cylindrical plug 421a for 
engaging the locking head 411a when downwardly inserted into the vertical 
socket 424. 
The opening spring 3 may have its lower spring end 31 retained on the 
washer 423 of the link holder 42 or having the lower spring end 31 
retained on the lugs 110 as pressed from the tube 11. 
When opening the umbrella of the present invention from FIG. 10 to FIG. 2, 
the push button 51 is depressed to push the lever 52 to disengage the hook 
portion 523 from the engaging holes 141, 131 of the upper and middle tubes 
14, 13 and the opening spring 3 will extend the tubes 14, 13, 11 and the 
lower runner 24 will be pulled upwardly by the drag means 4 to extend the 
rib assembly 2 and open the umbrella cloth C. 
When closing the umbrella, the skirt portion 241 of the lower runner 24 is 
pulled downwardly to retract the tubes 14, 13, 11 until the engaging holes 
141, 131 of the upper and middle tubes 14, 13 are engaged with the hook 
portion 523 and the spring 3 is also compressed to store its resilience 
ready for next opening operation. 
The present invention is superior to a conventional multiple-fold umbrella 
with the following advantages: 
1. The tubes 14, 13, 11 are made of light aluminum alloy for convenient 
carrying. The tube has concave polygonal sides for reinforcing the tube 
strength for resisting deformation of the tubes. The spring catches for 
coupling the tubes have been omitted for saving cost. 
2. When opening the umbrella, the lower runner 24 is pulled by the rope 43 
and link 41 of the drag means 4 to smoothly open the umbrella cloth C, 
like a rear umbrella ejected from a jet plane when landing on a short 
runway on a carrier for a buffer for the great impact force of the jet, to 
thereby dampen the great spring force as effected by the opening spring 3 
for preventing damage of the umbrella. 
3. The link holder 42 includes the plug 421 made of elastomers which may 
serve as a shock absorber to absorb the shock caused during the opening or 
closing operation of the umbrella, and also to reinforce the strength of 
the lower tube 11 as packed within the lower tube; and the washer 423 
which is provided for reinforcing the plug 421 and may be served for 
retaining the lower spring end 31 of the opening spring 3. The rigid 
washer 423 and the soft plug 421 may reinforce the strength of the 
light-weight umbrella of the present invention. 
The present invention may be modified without departing from the spirit and 
scope of the present invention.