Joint socket structure used in artificial Christmas trees

An improved joint socket structure used in artificial Christmas trees has enhanced safety, avoiding electrical wires from being squeezed and damaged by rotary branches. The main improvement is an arcuate shield disposed on each pivotal joint socket that connects the branches to the main trunk. The shield covers the space above the joint socket so that electrical wires wound around the Christmas trees will not get into the movement space of rotary branches. By way of this, the joint socket structure according to the invention can prevent electrical current leakage and electrical shocks caused by broken electrical wires.

BACKGROUND OF THE INVENTION
 The invention aims at the improvements of a prior art artificial Christmas
 tree structure that has such rotary branches that can be folded into a
 compact form. FIGS. 1 and 2 show the configuration of such an artificial
 Christmas tree. As can be seen from the drawings, an artificial Christmas
 tree includes a main trunk (10) with a plurality of pivotal joint socket
 (30), to each of which a branch (20) is attached. Each branch is provided
 with twigs (22) and needles. The rotary joint socket (30) has such means
 that allows branches (20) to be attached at a preset inclination and
 extends outwardly to display a form of Christmas tree. The branch (20) can
 be rotated around the pivotal joint socket (30) to close to the trunk (10)
 so that the artificial Christmas tree can be wrapped for further carrying
 or storage. Although the artificial Christmas tree structure provides
 convenience for delivery and storage, it still has a potential risk of
 electrical leakage. The cause consists in the pivotal joint structure.
 After the joint socket (30) is connected with a branch (20), the space
 (301) near the pivotal end of the branch is accessible from the outside.
 Electrical wires (60) wound around the artificial Christmas tree along
 with miniature light bulbs might drop into the open space (301), as a
 result of which when branches are stretched outwardly again electrical
 wires as well as light bulbs might be clamped and damaged by moving
 branches and pivotal joint socket (30). Because that an artificial
 Christmas tree must be able to provide enough strength to support the
 entire weight, the trunk (10) and branches (20) and the pivotal joint
 sockets (30) usually are made of metal materials. Thus if a branch (20)
 and a pivotal joint socket (30) clamp electrical wires therebetween, then
 the weight of a branch associated with twigs and needles will exert a
 great clamping force on the electrical wires (60). This may injure the
 sheath of electrical wires and leads to electrical leakage. Therefore such
 artificial Christmas tree structure is not satisfactory in safety. To
 solve the problem, the inventor has endeavored to overcome the above
 deficiency for a long time and finally worked out an improved Christmas
 tree structure. According to the invention, a shield (40) that can move
 along with the rotary motion of branches (20) is disposed on each pivotal
 joint socket to cover the space (301) above the socket to protect
 electrical wires from dropping into the rotary space and being clamped by
 rotary branches. Thus the structure according to the invention can
 eliminate the possibility of electrical leakage due to electrical wires
 clamped in a pivotal joint socket.
 Now the structural features and advantages of the invention will be further
 described in detail with reference to the accompanying drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
 With reference to FIGS. 3 to 8, a pivotal joint socket (30) according to
 invention is fixedly disposed on the main trunk (10) of an artificial
 Christmas tree. The rotary joint socket (30) being U-shaped is provided
 with hole (302) on both sides and is provided with a soft buffer (31) at
 bottom side. A shield (40) being made of insulted material is formed
 thereon. The shield (40) has its two bottom sides being rotary plate (41)
 and a pair of connecting plates (42) is formed therein. Each-space width
 between the plates (41), (42) is slightly larger than the thick of the
 socket (30). The rotary plates (41) and the connecting plates (42) are
 provided with the same axial hole (401). A circular hole (402) is formed
 on the top of shield (40) for connecting the branch (20), which has an end
 connecting hole (31). Such that, the shield (40) and the branches (20) are
 capable of placing on the joint socket (30) and both sides of the socket
 (30) are placed between the spaces of the plates (41) of the shield (40)
 and the connecting plates (42), as shown in FIG. 8. An insulated shaft
 (50) is inserted in the hole (302) of the socket (30), the connecting hole
 (21) of the branch (20), and the hole (401) of the shield (40). So the
 branch (20) and the shield (40) are connected rotary with the socket (30),
 as shown in FIGS. 6 and 7. Therefore, the shield (40) and the branch (20)
 can be rotary at the same time. When the branch (20) is closed, as in FIG.
 6, the space (301) of the joint socket (30) is shielded by the shield
 (40). This structure can prevent the electrical wires from falling into
 the space (301) of the socket (30) and avoiding the branch (20) clamping
 the wires when being rotary. Moreover, because the buffer (31), shield
 (40), and the shaft (50) are made of insulated materials, they separates
 the metal main trunk (10), branch (20), and the joint socket (30) to
 become insulation, that prevent from electrical leakage for safe use if
 the electrical wires are accidentally broken.