Beds – Crib – Folding
Reexamination Certificate
1999-11-10
2001-05-01
Trettel, Michael F. (Department: 3628)
Beds
Crib
Folding
C403S102000, C403S324000, C016S326000
Reexamination Certificate
active
06223366
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a foldable mechanism, and more specifically, to a foldable mechanism for a playpen.
2. Description of Prior Arts
A wide variety of playpens, have been designed, developed, and commercialized for many years. One of these designs is that the playpen may be folded for storage.
A well known foldable playpen, as shown in
FIG. 1
, uses a foldable structure
1
, comprising a coupling element
2
having a substantially U-shaped cross section; a pair of hollow rods
3
each having therein an engaging element
4
which may extend or retract with respect to the rods through a spring
5
, and pivotally screwed to the coupling element
2
by a screw
6
; a fixed block
7
secured in the coupling element
2
, having a cutout
8
for engaging with the engaging element
4
; and a press-down element
9
positioned below and slidably connected to the fixed block
7
for disengaging the engagement between the engaging element
4
and the fixed block
7
when the press-down element
9
is pressed down, or biased, with respect to the fixed block
7
by an external force. When the playpen is in an unfolded condition, the rods
3
are in a horizontal orientation with the engaging element
4
being engaged with the cutout
8
of the fixed block
7
. When the playpen is in a folded condition, the press-down element
9
is pressed to disengage the engaging element
4
from the fixed block
7
, such that the rods
3
may pivot to a vertical orientation.
In the prior art stated above, the foldable structure uses many parts, which not only complicate the structure but also increase the cost thereof.
Further, in the prior art, most of the parts, such as the fixed block, the press-down element, and the engaging elements, are made of, for example, plastic, which will further increase the manufacturing cost.
Therefore, a foldable playpen that uses few parts and is less expensive to manufacture would be very desirable.
SUMMARY OF THE INVENTION
According to an aspect of the invention, a simple foldable mechanism reduces the number of parts required.
According to another aspect of the invention, a foldable mechanism, where only one part is made of, for example, plastic, so as to further reduce the manufacturing cost.
The foldable mechanism for a playpen comprises a connection element having substantially an U-shaped cross section with two open side faces, one front face, and one rear face. The front and rear faces include a U-shaped cutout and a plurality of first openings and a plurality of second openings. A press-down block includes two sides each with a side groove having a narrow portion and an enlarged open end, front and rear faces each having a groove with two closed ends, an elongated through hole passing through the front and rear faces, and a hollow center with one closed end for receiving a spring. The press-down block is attached to the connection element by a first screw passing through the through hole and pressed against the spring, such that the press-down block can be pressed down, or biased, with respect to the connection element by an external force and moved back by the spring force. A pair of hollow rods each include therein a U-shaped reed spring with a protrusion on each outer face of the reed spring. Each rod is attached by a second screw to the connection element. In the unfolded condition, each hollow rod is pivotally rotated, the duck bill of the reed spring is slid along the narrow portion of the side groove of the connection block and the reed spring is expanded and the protrusions are engaged into the second openings provided on the front and rear faces of the connection element after the duck bill of the reed spring enters into the enlarged open end of the side groove. In the folded condition, the connection element is pressed down, or biased, so that the duck bill of the reed spring is pressed to exit the enlarged open end and enters into the narrow portion of the side groove, the reed spring is pressed, the protrusions are disengaged from the openings, and the rods may pivotally rotate to vertical orientation.
Preferably, the foldable mechanism further comprises a pair of screws passing through openings provided on the front and rear faces of the connection element so as to limit the rotation of the hollow rods.
Preferably, the press-down block further comprises protrusions extending from the two sides of the press-down block for positioning the press-down block in the cutout of the connection element without rotation.
Additional features of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the disclosed specific embodiment may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
REFERENCES:
patent: 5293656 (1994-03-01), Chan
patent: 5730542 (1998-03-01), Cheng
patent: 5803650 (1998-09-01), Wu
patent: 5906014 (1999-05-01), Zhuang
patent: 5978987 (1999-11-01), Wang
patent: 6082922 (2000-07-01), Cheng
Cheng Kenny
Trettel Michael F.
Woodcock Washburn Kurtz Mackiewicz & Norris LLP
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