Foldable joint for a playpen

A foldable joint for a playpen comprises a seat having two spaced apart side plates one of which defines holes respectively in both end and an integral connecting plate; two tubes respectively pivotally mounted on the end of the seat by a pivot, each having a first aperture and second aperture defined therein; and two U-shaped trips respectively disposed in the tubes, each having a first lug being inserted through the first aperture of the tube and the hole of the side plate, and a second lug being inserted through the second aperture of the tube; whereby, the tubes can be folded upward when the first lugs are pressed inward.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a foldable joint for a playpen, and more 
particularly to a foldable joint for a playpen which is safe for a baby in 
the playpen. 
2. Description of Related Art 
A playpen generally is designed with foldable joints so that the playpen 
can be stored. 
Referring to FIGS. 11 and 12, a conventional joint for a playpen comprises 
a seat (50), an arched plate (70) and two tubes (55). The seat (50) has 
two side plates (51) which are spaced apart, and an integral connecting 
plate (52). A hole (54) is defined in the central portion of the seat 
(50). Two apertures (53) are respectively defined beside the hole (54). 
The tubes (55), each having a through-hole (56) defined therein, are 
respectively pivotally mounted on the seat (50). A U-shaped trip (60) 
having two lugs (61) respectively formed on the front end thereof is 
disposed within the tube (55). The lugs will be inserted through the 
through-holes (56) and the apertures (53). The arched plate (70) is 
mounted on the seat (50) by a pin (55). Protrusions (73) are integrally 
formed on the internal wall of the arched plate (70). These protrusions 
(73) are aligned with the apertures (53) of the seat (50). Pressing the 
protrusions (73) will inwardly move the lugs (61), so that the tubes (55) 
can be pivoted about the seat (50). 
However, if the protrusions (73) are not aligned with the apertures (53) 
due to careless assembling, the lugs (61) can not be inwardly moved by 
pressing the protrusions (73), and the tubes (55) can not be pivoted. 
Another problem is that a baby in the playpen will be harmed if the joint 
is wrongly pressed and causes the playpen to unexpectedly fold. 
A foldable joint for a playpen in accordance with the present invention 
tends to mitigate and/or obviate the aforementioned problem. 
SUMMARY OF THE INVENTION 
The main object of the present invention is to provide a joint for a 
playpen which is ensured to fold when correctly operated. 
Another object of the present invention is to provide a joint for a playpen 
which will prevent it from inadvertently folding when improperly operated. 
Other objects, advantages and novel features of the invention will become 
more apparent from the following detailed description when taken in 
conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 1 and 2, the foldable joint for a playpen according to 
the present invention comprises a seat (10) and two tubes (20). 
The seat (10) has two side plates (11) which are spaced apart and an 
integral connecting plate (12). One side plate (11) respectively defines a 
hole (14) at both ends thereof. Two guide grooves (15) are respectively 
defined in the internal wall of the side plate and above the holes (14). 
The tubes (20) are pivotally mounted on the ends of the seat (20) by pins 
(13). Each of tubes (20) has a first aperture (21) and second aperture 
(22) defined therein. A U-shaped trip (30), which has a first lug (31) and 
a second lug (32) integrally formed thereon, is disposed in the tube. The 
first lug (31) of the trip (30) is inserted through the first aperture 
(21) and the hole (14) of the seat (10), and the second lug (32) is 
inserted through the second aperture (22) of the trip (30). The height of 
the first lug is less than that of the second lug (32), so that the first 
lug (31) is ensured to move inwardly behind the side plate (11) when the 
second lug (32) is pressed. 
A rotatable sleeve (40) is respectively mounted around each tube (20). The 
rotatable sleeve (40) defines a channel (45) to receive the second lug 
(32) and forms a shield (43) to cover the second lug (32). The sleeve (40) 
further comprises a slot (41) defined therein for receiving a screw (42) 
to fasten in the tube (20) to axially fixed the sleeve (40). A tongue (44) 
is integrally formed on the rotatable sleeve (40) to facilitate rotating 
the sleeve (40). 
To fold the joint, the rotatable sleeves (40) are firstly rotated to expose 
the second lug (32), as shown in FIG. 4. The second lug (32) is pressed 
inwardly, thereby moving the first lug (31) behind the side plate (11), as 
shown in FIGS. 5 and 6. Therefore, the tube (20) can be pivoted without 
interference by the first lug (31). 
When the playpen is used, because the sleeve is configured to cover the 
second lug (32) with the shield (43), the lug (32) can not be 
inadvertently operated, so that the joint will not be folded and harm the 
baby in the playpen. 
Referring to FIG. 7 and FIG. 8, the guide groove (15) provides a smoothly 
movement of the first lug (31), when the tube (20) is rotated. 
FIG. 9 shows another preferred embodiment of the present invention. The 
U-shaped trip (30) has two first lugs (31) and two second lugs (32) 
respectively formed on both sides thereof, while each of the two side 
plates has holes (14) defined therein for receiving the first lugs (31). 
FIG. 10 shows another yet preferred embodiment of the present invention. 
The first lug (31) is configured to have a tapered shape. 
The advantages of the present invention are: 
1. The height of the second lugs is less than that of the first lugs, so 
that it is easy to move the first lugs behind the side plate and the tubes 
are certain to pivot. 
2. The baby in the playpen will not be harmed with inadvertently or 
accidental operation because the second lugs are protected by the sleeve 
shields. 
It is to be understood, however, that even though numerous characteristics 
and advantages of the present invention have been set forth in the 
foregoing description, together with details of the structure and function 
of the invention, the disclosure is illustrative only, and changes may be 
made in detail, especially in matters of shape, size, and arrangement of 
parts within the principles of the invention to the full extent indicated 
by the broad general meaning of the terms in which the appended claims are 
expressed.