Field of the invention
This invention relates to a folding mechanism for folding flat structures. Background of the invention
Folding mechanism or latching mechanism generally vary depending upon the type of substance in which it is used. In US6082271 a latching mechanism is secured to the bottom of the table. The latching mechanism includes a latch mounting plate and a pull latch. The pull latch being slidably mounted on the latch mounting plate such that the pull latch is operable between a latched position and an unlatched position. The latching mechanism engages the hinge plate when the pull latch is in the latched position and disengages the hinge plate when the pull latch is in the unlatched position.
US6913297 provides a rotary latch mechanism for releasably securing a first structure to a second structure.
US20040046434A1 relates to a multi-position latch apparatus and method in which a seat latch mechanism accommodating a plurality of seatback positions, comprising an upper housing and a lower housing whereby the lower housing includes a recess for a striker to pass there through when the latch mechanism is in an unlatched position. Further, a latch assembly is provided and is operably supported by the lower housing, whereby the latch assembly is operable between a latched position and an unlatched position, and an actuation assembly operably supported by the upper and lower housings and in operable communication with the latch assembly to selectively toggle the latch assembly between the latched and unlatched position.
US20030146218A1 provides a Wafer carrier door with form fitting mechanism cover. The wafer container door has a latch mechanism cover adapted to retain and guide the latch mechanism components.
However, the above-mentioned documents do not disclose a folding mechanism which can be used for folding two parts of a flat surface such that the folding mechanism does not have any intrusion on the sides which approach each other during folding and there may be no gap between the two sides either before or after the folding .
Object and summary of the invention
To obviate the aforesaid drawback, the present invention provides a folding mechanism for folding of flat structures (P1 and P2).
To meet the above mentioned objective the present invention provides a folding mechanism for folding of flat structures (P1, P2) comprising:
• a plurality of links (L1 ,L2,L3),
• said link L1 is rigidly connected to a second flat structure (P2) having two
surfaces (P21, P22),
• said link L2 is connected to a first flat structure (P1) having two surfaces
(P11, P12) by a first rotation axis (R1) at one end and at the other end to
L1 by a second rotation axis (R2), and
• said link L3 is connected to L1 at one end by a third rotation axis (R3) and
to the first flat structure (P1) at the other end by a fourth rotation axis (R4).
The invention allows the physical embodiment of the mechanism to be completely on one side of the said surfaces, allowing the other side to be used for operational purposes.
Brief description of the accompanying drawings:
Figure 1 shows an embodiment of the invention to fold two flat structures P1 and P2 when the mechanism is in its starting position.
Figure 2 depicts the final position of the folding mechanism
Detailed description of the invention
Figure 1 shows an embodiment of the said mechanism in which we fold two bounded flat structures P1 and P2 (which are initially co-planar) with atleast one common edge such that the angle between them can be controlled by this mechanism. The first flat structure P1 consists of surfaces P1-i and P1a and the second flat structure P2 consists of surfaces P2-i and P22.
As can be seen the link L1 is rigidly connected to the second flat structure (P2), the link L2 is connected to the first flat structure (P1) by a first rotation axis (R1) at one end and at the other end to L1 by a second rotation axis (R2). The link L3 is connected to L1 at one end by a third rotation axis (R3) and to the second flat structure (P2) at the other end by a fourth rotation axis (RA4). The said linkages (L1,L2,L3) are attached only on the surfaces (P12 and P22) of said flat structures, and are completely contained in the direction of the outward normals of the surfaces P12 and P22. The surfaces P11 and P21 are completely free in the direction of their outward normal for other operational use. The lengths of the axis (R1,R2,R3) and their locations depends upon the application of the folding mechanism.
While the Figure 2 also shows the connectivity between the various links of the mechanism and the flat structures, it also depicts the final position of the folding mechanism. In this embodiment, between the initial position (Figure 1) and this final position a 85 degrees rotation of link L2 about axis R1 gives a 90 degrees
rotation of link L1 which is attached to second flat structure P2. Thus the structure P2 gets rotated by 90° with respect to the structure P1 between the initial and the final states.
This mechanism has been provided for folding the base of a transport container in the Indian Patent Application No. 620/DEL/2007. The mechanism is used in a variety of other applications.
All documents cited in the description are incorporated herein by reference. The present invention is not to be limited in scope by the specific embodiments and examples which are intended as illustrations of a number of aspects of the invention and any embodiments which are functionally equivalent are within the scope of this invention. Those skilled in the art will know, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein.

We claim:
1. A folding mechanism for folding of flat structures (P1, P2) comprising:
• a plurality of links (L1 ,L2,L3),
• said link L1 is rigidly connected to a second flat structure (P2) having two
surfaces (P21, P22),
• said link L2 is connected to a first flat structure (P1) having two surfaces
(P1i, Pla) by a first rotation axis (R1) at one end and at the other end to
L1 by a second rotation axis (R2), and
• said link L3 is connected to L1 at one end by a third rotation axis (R3) and
to the first flat structure (P1) at the other end by a fourth rotation axis (R4).

2. A folding mechanism as claimed in claim 1 wherein said linkages
(L1,L2,L3) are attached on the surfaces (Pla and P22) of said flat structures (P1,
P2) and are placed in the direction of the outward normals of the surfaces P12
and P22.
3. A folding mechanism for folding of flat structures substantially as herein
described with reference to the accompanying drawings.