Abstract:
A device for hanging bird feeders, wind chimes and similar objects from the limbs of trees having two opposed jaws that are spring closed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to devices for hanging articles from the limbs or branches of trees. A need exists for a device that will securely hold a load, that is easy to use and does not harm the tree. 
       SUMMARY OF THE INVENTION 
       [0002]    The present invention provides a device that can easily be attached to a tree limb up to three inches in diameter. The invention presented is a pair of opposed pivoting spring-loaded jaws that forming a hanger that encircles the tree limb and provides a means of attaching a device such as a bird feeder or wind chime. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL DRAWINGS 
         [0003]      FIG. 1  is a plan view of the invention. 
           [0004]      FIG. 2  is a perspective view of the invention. 
           [0005]      FIG. 3  is an exploded view of the invention. 
           [0006]      FIG. 4  is plane view of one the jaws of the invention. 
           [0007]      FIG. 5  is a perspective view of one of the jaws of the invention. 
           [0008]      FIG. 6  is an edge on view of one of the jaws of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0009]    Referring to  FIGS. 1 and 2 , the assembled Hanger  10  and its main components can be seen. The Hanger  10  comprises a Left Arm  11 , a Right Arm  12 , a Pivot Pin  13 , a Torsion Spring  14 , a Locking Ring  15 , and a Clevis  16 . The arms of the Hanger  10  are identical and a single arm can been seen in  FIGS. 4 and 5 . The arms  11  and  12  have a Jaw  21 , a plurality of inward facing Teeth  17 , a Handle  22 , an offset Extension  23 , a Spring Pocket  24  and a Stop  25 . The Handle  22  protrudes at an angle of approximately 15 degrees from the centerline of the Hanger  10 . The angle of the Handle  22  is set so that when the Jaws  11  and  12  are fully open against the Stops  25 , there is sufficient space between the tips of the Jaws  21  to allow the Hanger  10  to be placed over a three inch diameter branch. 
         [0010]    When the Hanger  10  is assembled, the Arms  11  and  12  are juxtaposed and secured together using the Pivot Pin  13  and the Locking Ring  15  as shown in  FIG. 2 . The Clevis  16  and the Torsion Spring  14  are also secured to the Hanger  10  by the Pivot Pin  13  as shown in  FIGS. 2 and 3 . The Hanger  10  is operated by squeezing the Handles  22  toward each other, forcing the Arms  11  and  12  open. The Arms  11  and  12  are then secured around a tree limb or other such object and the force on the Handles  22  is released, allowing the Arms  11  and  12  to close due to the pressure exerted upon them by the Torsion Spring  14 . A Stop  25  provided on each Handle  22  prevents the Hanger  10  from opening beyond a predetermined distance. 
         [0011]    An important element of the inventiveness and functionality of the Hanger  10  is the shape of the Jaws  21  and the placement of the Pivot Pin  13  and how these elements shape the force vectors on the Arms  11  and  12 . Referring to  FIG. 1 , it can be seen that the opening described by the Arms  11  and  12  when the Jaws  21  just meet, is roughly semicircular. The Jaws  21  extend beyond a point that would describe a full one hundred eighty degree semicircle. When in use, a load such as a bird house or wind chime will be secured with a chain or rope or other means to the Clevis  16 . The force from the load secured to the Clevis  16  will be transmitted to the Jaws  11  along a centerline drawn though the center of the Pivot Pin  13 , assuming the Hanger  10  is centered on the branch, which will be it&#39;s natural position, to the point where the Jaws  21  intersect. When the Hanger  10  is used on a three inch or smaller diameter branch the Jaws  21  overlap. The Teeth  17  engage with the branch thereby transmitting the force due to the load on the Clevis  17  upward into the Jaws  21 . The shape of the Teeth  17  allows very little of the force due to the load to be transmitted perpendicularly, i.e. in a direction forcing the Jaws  11  and  12  open. The majority of the force will be transmitted in a direction directly opposite to the force due to the load. A semicircular shape was chosen for the Teeth  17  to minimize damage to the tree branch upon which the Hanger  10  will be placed. 
         [0012]    The semicircular shape of the Jaws  21  transmits the force from the load to the Hanger  10  along a force vector with a vertical component proportional to the sine of an angle described by a line running from the center of the opening described by the Jaws  21  to the tips of the Jaws  21 , and a horizontal component proportional to the cosine of the same angle. As the Jaws  21  move to a more open position, the force from the load acting in the horizontal direction which tends to force the jaws open, becomes smaller. At the same time, the force on the Jaws  11  and  12  from the Torsion Spring  14 , tending to force them in a closed direction becomes greater. The further open the Hanger  10  becomes due to the load on the Clevis  16 , the less easily it opens while at the same time it the more it is forced closed by operation of the Torsion Spring  14 . These force relationships remain constant throughout the usable range of the Hanger  10 . 
         [0013]    Referring to  FIG. 6 , the offset Extension  23  portions of the Jaws  21  can be seen. When the Jaws  11  and  12  are fitted onto the Pivot Pin  13 , the Extensions  23  of each Jaw  21  are aligned next to each other, and allow a portion of the thickness of the Jaws  21  to occupy the same plane. This allows the tips of jaws to meet as shown in  FIG. 2 . The Jaws  21  are forced closed by the action of the Torsion Spring  14 . The Jaws  21  loosely fit on the Pivot Pin  13  and are made of a flexible plastic so that instead of meeting at the tips when the Hanger  10  is closed, they may be made to slide past each other allowing the Hanger  10  to be easily clamped on successively decreasing diameters of branches. 
         [0014]    Referring  FIG. 5  the mechanism for transmitting force from the Torsion Spring  14  to each of the Jaws  21  can be seen. A Spring Pocket  24  is provided in each Extension  13  to hold the Torsion Spring  14 . The Torsion Spring  14  used in the present invention can be seen in the exploded view of  FIG. 3 . The depth of the Spring Pocket  24  is sized to allow full engagement of one of the legs of the Torsion Spring  14  while allowing the body of the Torsion Spring  14  to extend out of the Spring Pocket  24  so the opposite leg of the Torsion Spring  14  may be fully engaged in the Spring Pocket  24  of the Extension  13  of the other Jaw  21 . The legs of the Torsion Spring  14  push against a side of the Spring Pocket  24 , thereby forcing the upper portion of the Jaws  21  together. The Torsion Spring  14  is sized to allow the Hanger  10  to be easily opened with one hand and to force the Jaws  21  and  12  closed from their full open position to a diameter of about one and a half inches. 
         [0015]    Referring to  FIG. 4 , it can be seen that the Extension  23  is provided with a centrally located Pin Hole  26 . The Pin Hole  26  is sized to accommodate the Pivot Pin  13  and leave sufficient clearance between the Pivot Pin  13  and the sides of the Pin Hole  26  so that the end of the Jaws  21  may slide past each other when the Hanger  10  is closed.