Patent Abstract:
A hinge consists of a movable upper leaf, a lower leaf, a transmission and a pair of caps for anchoring a panel of a table or a storage rack or a merchandise shelf fastened to the hinge on an extending or folding position. The transmission connects the movable upper leaf and the lower leaf to make the movable upper leaf turnable. The transmission has a retaining mechanism to engage with the movable upper leaf to allow the panel and the upper leaf extending and anchoring within allowable angles, or to disengage with the upper leaf to move the panel to a folding position.

Full Description:
FIELD OF THE INVENTION 
     The present invention relates to a hinge and particularly to a hinge allowing to be turned and anchored on selected angles. 
     BACKGROUND OF THE INVENTION 
     The commonly used tables, racks or shelves are mostly designed for use in a fixed assembly manner. While such type of design may serve some practical purposes, it also creates many problems, notably: 
     1. When conventional fixed tables or racks are being carried or transported to where they are required, the door panels, table tops or racks have to be fixedly nailed and fastened for use. The finished and fixed tables or racks often occupy a large amount of space and are difficult to move and transport, and create a lot of storing inconveniences and incur additional handling time and costs. 
     2. The fixed tables and racks tend to get damages easily on table top surfaces or rack structures during moving and transportation. 
     3. Once the tables or racks are fixedly assembled, they have limited spaces for holding goods and are less flexible to use or deploy. 
     SUMMARY OF THE INVENTION 
     In view of aforesaid disadvantages, the primary object of the invention is to provide an improve hinge for achieving the following advantages: 
     1. The hinge of the invention provides a position anchoring function to enable a table or a storage rack or merchandise display shelf be extended for use or folded to a small space for storing depending on requirements. The hinge of the invention has a driving ratchet wheel coupling with an upper leaf and a lower leaf and a transmission means engaging with the driving ratchet wheel such that the upper leaf may be turned and a retainer may anchor the upper leaf on a selected angle (between 0 and 120 degrees). When the upper leaf is turned beyond the upper anchoring limit, a jutting key is moved to push and disengage the retainer to enable the upper leaf be moved in a folding condition. 
     2. The upper leaf of the hinge may be fastened to a table top, a storage rack or a merchandise shelf to extend or fold against the lower leaf. When the upper leaf is extended on a selected angle, the jutting keys on two ends of the ratchet wheel and the retainers in rotary elements located in driven ratchet wheels form a brake relationship to produce a secured anchoring so that the table top or storage rack may be extended and latched on a desired position for use. 
     3. Table tops, storage racks or merchandise shelves adopt the hinge of the invention can be extended at selected angles or folded to a small space for storing, thus have greater flexibility and wider applications. 
    
    
     The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of the invention. 
     FIG. 2 is a perspective view of the invention. 
     FIG. 3 is an exploded view of the transmission means of the invention. 
     FIG. 4 is a schematic view of the invention in an use condition (fastening to a storage rack or a merchandise shelf). 
     FIG. 5 is a schematic view of the upper leaf of the invention extended to ninety degrees. 
     FIG. 6 is a front sectional view according to FIG.  5 . 
     FIG. 7 is a schematic view of the upper leaf of the invention extending to allowable angles (0-120 degrees). 
     FIG. 8 is a schematic view of the upper leaf of the invention extending beyond the allowable angle (120 degrees). 
     FIG. 9 is a front sectional view according to FIG.  8 . 
     FIG. 10 is a schematic view of the invention in a folding condition. 
     FIG. 11 is an exploded view of the invention coupling with a connection dock. 
     FIG. 12 is a side view of the invention coupling with a connection dock according to FIG.  11 . 
     FIG. 13 is a schematic view of the movable upper leaf of the invention in an use condition according to FIG.  11 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Refer to FIGS. 1,  2 , and  3  for an embodiment of the invention. The invention aims at providing a hinge adopted for use on tables, storage racks and merchandise display shelves that require to be extended and anchored at selected positions when in use and folded when not in use. The hinge of the invention consists of a movable upper leaf  1 , a lower leaf  2 , a transmission means  3  and a pair of caps  4 . 
     The movable upper leaf  1  includes an upper barrel  10  formed in a middle section thereof with an upper barrel plane  1000  forming on a peripheral side. The upper barrel  10  has a barrel hole  100  formed therein for housing a driving ratchet wheel  11  which has a ratchet plane  113  corresponding to the upper barrel plane  1000 . The driving ratchet wheel  11  is fastened to the upper barrel  10  by means of a set screw  101  (or a rivet). The movable upper leaf  1  further has a fastening plate  102  for fastening to a panel  600 . 
     The driving ratchet wheel  11  has two ends each has driving ratchet teeth  110  formed thereon to engage with driven ratchet teeth  320  formed on a lateral end of a driven ratchet wheel  32  housed in a lower barrel  21  of the lower leaf  2 . The two ends of the driving ratchet wheel  11  further have respectively an indented trough  111  which has two jutting keys  112  formed on an upper side and a lower side opposing to each other. The ratchet plane  113  is formed on the peripheral surface of the driving ratchet wheel  11  and has a screw hole  1130  formed in the center thereof to couple with and fasten to the upper barrel plane  1000  of the upper barrel  10  at a selected angle to facilitate assembly. 
     The lower leaf  2  has a center notch  20  and two lower barrels  21  formed at two ends. Each lower barrel  21  has a lower barrel plane  210  formed on an inner top side thereof (when the driving ratchet teeth  110  do not engage with the driven ratchet teeth  320  and the movable upper leaf  1  subjects to a weight on the upper side, the lower barrel plane  210  contacts a driven ratchet plane  324  formed on the driven ratchet wheel  32  to restrict the driven ratchet wheel  32  to move only in a straight line without turning) to contact the driven ratchet plane  324  formed on the peripheral surface of the driven ratchet wheel  32 . The lower barrel  21  has a lower barrel center hole  211  which has internal screw threads  2110  formed therein. The lower barrel center hole  211  houses the driven ratchet wheel  32  which has a rotary push element  31  located therein, and the internal screw threads  2110  may engage with external screw threads formed on the cap  4 , and the lower leaf  2  may be fastened to a desired wall surface  60 . 
     The transmission means  3  includes a pintle  30  which has two ends forming respectively a pintle stem  300  to couple with the rotary push element  31 , driven ratchet wheel  32  and a spring  33 . The pintle  30  is housed in the upper barrel  10  of the movable upper leaf  1  and the lower barrels  21  of the lower leaf  2  and has the two ends coupling with the caps  4 . 
     The rotary push element  31  has two retainers  310  located on one lateral side at an upper and a lower position opposing to each other to form a brake relationship with the jutting keys  112  of the driving ratchet wheel  11  during turning. The rotary push element  31  further has an indented recess  311  forming in the lateral side to couple with the pintle  30 . The rotary push element  31  has another lateral side opposing to the retainers  310  and having an arched lug  312  to wedge in a wedge slot  322  formed in a housing space  321  in the interior of the driven ratchet teeth  320  of the driven ratchet wheel  32 . The rotary push element  31  also has a center hole  313  to allow the pintle stem  300  of the pintle  30  to run through. 
     The driven ratchet wheel  32  has one end forming the driven ratchet teeth  320  to engage with the driving ratchet teeth  110  on two sides of the driving ratchet wheel  11 , and has the wedge slot  322  formed in the interior housing space  321  to engage with the arched lug  312  of the rotary push element  31 . The driven ratchet wheel  32  has another end forming a strut  323  to couple with the spring  33  and the driven ratchet plane  324  forming on a top peripheral side to contact an inner side of the lower barrel plane  210  of the lower barrel  21  of the lower leaf  2 . 
     The spring  33  has one end  330  coupling with the strut  323  of the driven ratchet wheel  32  and another end  331  sealed by the cap  4 , and is housed in the lower barrel  21  of the lower leaf  2 . 
     When in use, as shown in FIG. 4, the movable upper leaf  1  is fastened to a bottom end of an upper panel  600  of a table  6  (or a storage rack, or merchandise shelf  6 ′), and the lower leaf  2  is fastened to a wall surface  60 . When to unfold and extend the upper panel  600 , turn the upper panel  600 , and the driving ratchet teeth  110  of the driving ratchet wheel  11  housed in the upper barrel  10  of the movable upper leaf  1  engage with the driven ratchet teeth  320  of the driven ratchet wheel  32  housed in the lower barrel  21  of the lower leaf  2 , the movable upper leaf  1  attached to the bottom end of the panel  600  may be turned and extended to an use angle (between 0 and 120 degrees, FIG. 5 shows an embodiment with 90 degrees). The jutting keys  112  on two sides of the driving ratchet wheel  11  are moved to hit and are retained by the retainers  310  of the rotary push elements  31  housed in the lower barrels  21  of the lower leaf  2 , thus the movable upper leaf  1  and the upper panel  600  are extended and anchored on a desired usable angle (as shown in FIG.  6 ). When the movable upper leaf  1  is turned and extended beyond the allowable angle (over 120 degrees, as shown in FIGS. 7,  8  and  9 ), the jutting lugs  112  of the driving ratchet wheel  11  drive the retainers  310  of the rotary push element  31  turning, and the arched lug  312  is moved away from the wedge slot  322 , and the driven ratchet wheels  32  are pushed outwards simultaneously in a straight line, and meanwhile the driving ratchet teeth  110  of the driving ratchet wheel  11  and the driven ratchet teeth  320  of the driven ratchet wheel  32  are disengaged (separating), thus the movable upper leaf  1  may be turned and moved back in the reverse direction. Consequently the jutting keys  112  at two ends of the driving ratchet wheel  11  are moved in the reverse direction and drive and move the retainers  310  of the rotary push element  31 , and the arched lug  312  on another side of the rotary push element  31  is moved and wedged in the wedge slot  322  of the driven ratchet wheel  32 . As a result, the upper panel  600  is latched on the movable upper leaf  1  to form a folding condition (as shown in FIG.  10 ). 
     Refer to FIGS. 11 and 12 for another embodiment of the invention that couples with a connection dock. The lower side of the movable upper leaf  1  is fastened to a connection dock  7 . The connection dock  7  has two flanges  70  at two ends for fastening to a panel  600  of table  6  or a storage rack or merchandise shelf  6 ′ which is fastened to a wall surface  60 . The connection dock  7  has a bridge plate  71  which has two slots  711  formed on two sides for coupling with screws  710 . There is a fastening spring  72  located above the bridge plate  71  that has two arched ends  720  to engage with the rear ends of the screws  710 . By means of the elasticity of the spring  72 , when the panel  600  fastened to the upper leaf  1  is extended more than 90 degrees, the panel  600  hits the wall surface  60  and is pushed forwards, therefore the panel  600  may constantly contact the wall surface  60  (as shown in FIG. 13) without forming a gap with the wall surface  60 , thus form a neat appearance.

Technology Classification (CPC): 8