Abstract:
A tri-folded umbrella is disclosed. An enhanced frame of the umbrella comprises pivotably coupled first, second, and third yoke-shaped pivot members formed of plastic, first, second, and third latches, first, second, third ribs, first and second links, and a stretcher. The invention enables an easy assembly and a more compact size after folding.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to umbrellas and more particularly to a tri-folded umbrella with improved characteristics such as enhanced frame, easy assembly, and more compactness. 
     2. Description of Related Art 
     Umbrella frame designs take many different forms. A conventional tri-folded umbrella is shown in FIG.  8 . Such umbrella frame  70  has a number of disadvantages as observed by the present inventor. For example, a rivet is used in each of seven pivot joints  71  to  77 . However, it is known that riveting is a tedious task. Also, uniform quality of riveting on the pivot joints  71  to  77  for each frame element is not easy to control. Typically, there are about total 42 to 56 pivot joints in an umbrella frame. Unfortunately, one defective pivot joint will soon make the whole umbrella unusable after a short period of time due to rust in the pivot joints. Further, stress tends to concentrate on the pivot joints. As a result, the frame is susceptible of break in folding or expanding the umbrella. 
     An FRP umbrella for solving the problem of rust in the pivot joint caused by riveting is proposed. However, the FRP umbrella still suffered from several disadvantages. For example, ribs of the FRP umbrella frame are shaped as cylindrical bar for providing a sufficient support to the frame. Also, a variety of plastic molded connecting elements and pivot elements are fitted at two ends and in intermediate section of the cylindrical rib, respectively. As such, each frame element is increased in size, resulting in a bulky FRP frame. This can cause difficulties in storage, packing, and delivery of the umbrella. Hence, a commercialized tri-folded FRP umbrella is still not available after such technique has been developed for more than 20 years. Thus, continuing improvements in the tri-folded FRP umbrella frame are constantly being sought. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a tri-folded umbrella having the advantage of smooth folding operation. 
     It is another object of the present invention to provide a tri-folded umbrella having the advantages of being lightweight, easy to pack, and delivery. 
     It is a further object of the present invention to provide an enhanced strength, durable tri-folded umbrella. 
     The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view depicting a partial frame of a tri-folded umbrella according to the invention; 
     FIG. 2 is a perspective view depicting the assembled, partially folded frame shown in FIG. 1 with shank removed; 
     FIG. 3 is a cross-sectional view depicting the assembled, partially folded frame shown in FIG. 1; 
     FIG. 4 is a view similar to FIG. 3 where the fully extended frame is being folded; 
     FIG. 5 is a cross-sectional view depicting folded first latch and first pivot member according to the invention; 
     FIG. 6 is a cross-sectional view depicting folded second latch, third latch, second pivot member, and third pivot member according to the invention; 
     FIG. 7 is a side view depicting the fully folded frame according to the invention; and 
     FIG. 8 is a side view depicting a partial frame of a conventional tri-folded umbrella. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1,  2 , and  3 , there is shown a tri-folded umbrella constructed in accordance with the invention in which an umbrella cloth is omitted for a brief of description. A frame  10  of the umbrella comprises a shank  11 , an upper ring  12  having a plurality of slits  120  equally spaced around, a sliding lower ring  13  having a plurality of slits  130  equally spaced around, and a folding radial frame section comprising a plurality of units, equal to the number of the slits  120  or  130 . Each unit comprises a plastic connection cylinder  20  having a flat extension  200  at one end pivotably coupled to the slit  120  and a bore  201  at the other end for receiving one end of a first rib  14  and a plastic connection cylinder  21  having a flat extension  210  at one end pivotably coupled to the slit  130  and a bore  211  at the other end for receiving one end of a stretcher  15 . 
     A first latch  30  is put on the first rib  14  and comprises a U-shaped recess  302  in its center, a first projection  300  at one end, and a second projection  301  at the other end. A bore  3000  of the first projection  300  is communicated with a bore  3010  of the second projection  301  via the intermediate recess  302 . The recess  302  has an oblique plane  303  extended toward the second projection  301 . A plastic yoke-shaped first pivot member  40  is pivotably coupled to the other end of the stretcher  15  and comprises a bore  400  at one end, a pin  401  at the mouth of the other end, a first opening  402  defined by the pin  401 , a second opening  403  adjacent the first opening  402 , a recessed portion  404  on the mouth of the second opening  403 , and a U-shaped element  405  having two horizontal shoulders  4050  rested on the recessed portion  404  and a central portion inserted into the second opening  403  and projected from the bottom surface of the first pivot member  40 . The first latch  30  passes the opening  402  so that the recess  302  in contact with the pin  401 . 
     A plastic yoke-shaped second pivot member  41  comprises a bore  410  at one end put on the other end of the first rib  14 , a pin  411  at the mouth of the other end, a first opening  412  defined by the pin  411 , a second opening  413  adjacent the first opening  412 , a recessed portion  414  on the mouth of the second opening  413 , and a U-shaped element  415  having two horizontal shoulders  4150  rested on the recessed portion  414  and a central portion inserted into the second opening  413  and projected from the top surface of the second pivot member  41 . 
     A plastic second latch  31  passes the first opening  412  and comprises a recess  312  in contact with the pin  411 , a cylindrical first projection  310  at one side having an arcuate flat extension  3101 , a hole  3102  at an open end of the extension  3101 , and a bore  3100 , a cylindrical second projection  311  at the other side having a bore  3110 , and an oblique plane  313  extended from the recess  312  toward the second projection  311 . The bore  3110  is communicated with the bore  3100  via the intermediate recess  312 . 
     A plastic yoke-shaped third pivot member  42  comprises a bore  420  at one end put on the other end of a second rib  16 , a pin  421  at the mouth of the other end, and an opening  422  defined by the pin  421 . A plastic third latch  32  is formed at one end of a third rib  17 . The other end (not shown) of the third rib  17  is stitched to a periphery of an umbrella cloth as well known in the art. The third latch  32  passes the opening  422  and comprises a recess  322  in contact with the pin  421 . Similar, to the second latch  31 , the third latch  32  further comprises a cylindrical first projection  320  at one side having an arcuate flat extension  3201 , a hole  3202  at an open end of the extension  3201 , and a bore  3200 , a cylindrical second projection  321  at the other side having a bore  3210 , and an oblique plane  323  extended from the recess  322  toward the second projection  321 . The bore  3200  is communicated with-the bore  3210  via the intermediate recess  322 . 
     A first link  50  comprises a first hooked end  51  inserted into the U-shaped element  415  and a second hooked end  52  inserted into the hole  3202  so as to pivotably couple the third latch  32  and the second pivot member  41  together. Similarly, a second link  60  comprises a first hooked end  61  inserted into the U-shaped element  405  and a second hooked end  62  inserted into the hole  3102  so as to pivotably couple the second latch  31  and the first pivot member  40  together. Moreover, one end of the third rib  17  is inserted through the bores  3210  and  3200  for fastening. One end of the second rib  16  is inserted through the bores  3110  and  3100  for fastening. The first rib  14  is inserted through the bores  3000  and  3010  for fastening with one end of the first rib  14  fastened in the bore  201  and the other end thereof fastened in the bore  410 . The stretcher  15  is fastened between the bores  211  and  400 . As a result, the pair of the first latch  30  and the first pivot member  40 , the pair of the second latch  31  and the second pivot member  41 , the pair of the third latch  32  and the third pivot member  42  are pivotably coupled together respectively. 
     It is to be noted that the U-shaped elements  405  and  415  are one kind of pivotal joint members. They can be substituted by any other forms, such as pivotal ring or pivotal pin integrally formed with the second opening or recess, or integrally formed on one surface of the first and second pivot members  40 ,  41  to enable the first and second links  50 ,  60  to insert or hook thereto to attain the same purpose of the U-shaped element as mentioned above. It means that the U-shaped element  405 ,  415  is not only one form of the pivotal joint members. 
     Referring to FIGS. 4 to  7  in conjunction with FIG. 3, a fold operation of the invention will now be described in detail below. The fully extended frame  10  begins to fold when a user slides down the lower ring  13 . In response as shown in FIG. 4, the third rib  17  pivots clockwise as indicated by a right arrow A 1 , the second rib  16  and the first link  50  pivot counterclockwise as indicated by a central arrow A 2 , and the first rib  14  and the second link  60  pivot clockwise as indicated by a left arrow Al respectively. Finally, a fully tri-folded umbrella frame  10  is formed as shown in FIG.  7 . 
     Note that the provisions of the arcuate flat extensions  3101  and  3201  at the second latch  31  and the third latch  32  can reduce size of the folded frame  10 . Inclined recesses  406 ,  416 , and  426  (see FIGS. 3-6) formed on one side of the first pivot member  40 , the second pivot member  41 , and third pivot member  42  corresponding to the second projections  301 ,  311 ,  321  of the first latch  30 , the second latch  31 , and the third latch  32  respectively will facilitate the folding and further reduce size of the folded frame. 
     While the invention herein disclosed has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.