Folding container

A lock member L1 including an operation portion L1a and a lock bar L1b is disposed on each of first opposite side walls 2 to be brought down firstly toward a bottom portion 1, and a pivotal shaft 13 formed in the operation portion is pivotally supported in a bearing hole 2g2 formed in each of the first opposite side walls to be brought down firstly toward the bottom portion. To allow cancellation of a lock state between the lock member and each of second opposite side walls to be brought down secondly toward the bottom portion, the operation portion is pivotally moved downward. During an unlocking operation, even when an operator pivotally moves the operation portion included in the lock member, the operation portion is prevented from being tilted. Thus, the lock bar of the lock member can be used to reliably perform the unlocking operation.

FIELD OF THE INVENTION

The present invention relates to a folding container in which side walls disposed so as to surround a bottom portion can be folded so as to lie on top of the bottom portion.

BACKGROUND OF THE INVENTION

Folding containers are conventionally known which are composed of long side walls connected, via hinge members, to respective opposite long side portions of a bottom portion formed so as to have a rectangular planar shape and short side walls also connected, via hinge members, to respective opposite short side portions of the bottom portion. The long side walls and the short side walls are set up perpendicularly to the bottom portion to assemble the side walls and the bottom portion into a box form. Furthermore, when the folding container is folded, the long side walls and the short side walls are folded so as to lie on top of the bottom portion. With the folding container assembled into the box form, the long side walls and the short side walls are locked by lock members so as to prevent the long side walls or the short side walls from falling down toward the bottom portion.

By way of example, the Unexamined Japanese Patent Application Publication (Tokkai) No. 2003-40263 discloses a folding container in which a locking operation and an unlocking operation are performed as follows. An operation portion of a lock member disposed on each short side wall is moved in a vertical direction. Furthermore, the vertical movement of the operation portion is converted into horizontal movement via an appropriate mechanism such as a link mechanism to move a bar-like member to move in a horizontal direction. The tip of the bar-like member is thus inserted into or removed from an engaging portion formed in a corresponding long side wall. Consequently, the long side walls and the short side walls are locked or unlocked so as to prevent the short side walls from falling down toward a bottom portion.

According to the above-described conventional folding container, to fold the folding container assembled into the box form, an operator pushes the operation portion downward. However, depending on a position where the operator pushes the operation portion downward, the operation portion may be tilted during the downward movement instead of being moved downward in a horizontal state. Where the operation portion is tilted during the downward movement, the paired bar-like members positioned on the right and left of the operation portion vary in projection amount or retraction amount. This disadvantageously results in an unreliable unlocking operation.

Furthermore, the vertical movement of the operation portion is converted into the horizontal movement of the bar-like members via a complicated mechanism. Thus, a heavy transmission loss is involved in the conversion of the vertical movement of the operation portion into the horizontal movement of the bar-like members. Thus, a strong force is required to move the operation portion in the vertical direction, hindering a quick unlocking operation.

SUMMARY OF THE INVENTION

An object of the present invention is to solve the problems with the above-described conventional folding container.

To accomplish the above-described object, the present invention provides a folding container having first opposite side walls which, when the folding container is in an assembled box form, are brought down firstly toward a bottom portion, and second opposite side walls which are brought down secondly toward the bottom portion after the first opposite side walls haven been brought down, wherein a lock member comprising an operation portion and a lock bar is disposed on each of the first opposite side walls to be brought down firstly toward the bottom portion, and a pivotal shaft formed in the operation portion is pivotally supported in a bearing hole formed in each of the first opposite side walls to be brought down firstly toward the bottom portion, and wherein to allow cancellation of a lock state between the lock member and each of the second opposite side walls to be brought down secondly toward the bottom portion, the operation portion is, when the lock member is in the locked state, pivotally moved upward or downward.

In the folding container having the first opposite side walls which, when the folding container is in the assembled box form, are brought down firstly toward the bottom portion and the second opposite side walls which are brought down secondly toward the bottom portion after the first opposite side walls haven been brought down, the lock member comprising the operation portion and the lock bar is disposed on each of the first opposite side walls to be brought down firstly toward the bottom portion, and the pivotal shaft formed in the operation portion is pivotally supported in the bearing hole formed in each of the first opposite side walls to be brought down firstly toward the bottom portion. Furthermore, to allow the lock member to be unlocked from each of the second opposite side walls to be brought down secondly toward the bottom portion, the operation portion is, when the lock member is in the locked state, pivotally moved upward or downward. Thus, during the unlocking operation, the operation portion is prevented from being tilted even when the operator pivotally moves the operation portion belonging to the lock member. Consequently, the unlocking operation can be reliably achieved using the lock bar belonging to the lock member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of the present invention will be described below. However, the present invention is not limited to the embodiment, and any other embodiment is possible without departing from the spirit of the present invention.

As shown inFIG. 1, a folding container according to the present invention is composed of a bottom portion1, long side walls2A hinged to respective long-side bank portions la of the bottom portion1, and short side walls3A hinged to respective short-side bank portions1bof the bottom portion1. In the present embodiment, each of the long-side bank portions1ais formed to be lower than each of the short-side bank portions1b.

When the folding container is in an assembled box form as shown inFIG. 1, firstly, the long side walls2A are brought down so as to lie on top of the bottom portion1. Then, the short side walls3A are brought down so as to lie on top of the long side walls2A laid on top of the bottom portion1. Thus, as is well known, the folding container can be folded into a low, compact form. Then, when the folding container is in a folded form, the short side walls3A are set up vertically, and the long side walls2A are set up vertically. Then, as shown inFIG. 1, the folding container can be assembled into the box form.

Now, the short side wall3A will be described with reference toFIGS. 1 and 2.

The short side wall3A has a plate-like portion3a. An upper-end horizontal rib3bis formed at the upper end of the short side wall3A. Furthermore, a vertically long short side wall-side engaging member3cis formed at each of opposite vertical ends of the short-side wall; the short side wall-side engaging member3cis perpendicular to the plate-like portion3aand to an inner surface (the surface which, when the folding container is assembled into the box form, is positioned inside the folding container assembled into the box form)3a1of the plate-like portion3a. A vertically long prismatic block (hereinafter simply referred to as a corner block)3dis formed in a corner portion formed by the inner surface3a1of the plate-like portion3aand a vertically long band-like plate (hereinafter referred to as an end-side vertical plate)3c1included in the short wall-side engaging member3cand which is perpendicular to the inner surface3a1of the plate-like portion3a. Moreover, a pair of opposite, horizontal projecting pieces3d2and a vertical projecting piece3d3are formed at the upper end of a surface3d1of a corner portion vertically-long block3dwhich lies parallel to the plate-like portion3a; the vertical projecting piece3d3couples together the ends of the horizontal projecting piece3d2which lie opposite the end-side vertical plate3c1. An engaging recess portion3eis formed at the upper end of the corner block3dwhich is surrounded by the horizontal protruding pieces3d2, the vertical protruding piece3d3, and the surface3d1of the corner block3d. Additionally, on the end-side vertical plate3c1, fitting holes3fare formed in the vertical direction near the pair of horizontal protruding pieces3d2.

Now, the long side wall2A will be described with reference toFIGS. 1,3, and4.

The long side wall2A has a plate-like portion2a. An upper-end horizontal rib2bis formed at the upper end of the long side wall2A. A vertically long side wall-side engaging member2cis formed at each of the opposite vertical ends of the long side wall2A and extends in the direction of the plate-like portion2aand outward. Fitting projecting portions2c1are formed at the upper end of the long side wall-side engaging portion2cat a predetermined interval therebetween in the vertical direction and perpendicularly to the plate-like portion2a; the fitting projecting portion2c1extends over the outer surface2a1of the plate-like portion2a(the surface which, when the folding container is assembled into the box form, is positioned outside the folding container assembled into the box form). Moreover, an upper horizontal rib2dis formed in the upper portion of the plate-like portion2aat a predetermined distance from the upper-end horizontal rib2bso as to extend to the long side wall-side engaging member2c.

Paired opposite central coupling vertical ribs2eare formed at a predetermined distance from each other so as to couple a central area of the upper-end horizontal rib2band a central area of the upper horizontal rib2d. The upper-end horizontal rib2b, the upper horizontal rib2d, the pair of opposite central coupling vertical ribs2e, and the outer surface2a1of the plate-like portion2aform a central space portion A1.2fis a regulation portion disposed in a corner portion formed by the bottom surface of the upper-end horizontal rib2bpositioned in the central space portion A1and a central space portion A1-side side surface of the coupling vertical rib2e. The regulation portion2fis formed by a horizontal regulating rib2f1and a vertical rib2f2.

2gis a pair of opposite pivotal shaft supporting blocks projected, at a predetermined distance from each other, on the outer surface2a1of the plate-like portion2apositioned between the regulation portion2fand the upper horizontal rib2d. Each of the pivotal shaft supporting blocks2ghas a prismatic block main body2g1. A guiding inclined surface2g2is formed in a central portion of a corner portion formed by opposite vertical side surfaces2g1′ of the block main body2g1and an outer surface2g1″ parallel to outer surface2a1of the plate-like portion2a. A bearing hole2g3is formed in a central portion of the vertical side surface2g1′ lying very close to the outer surface2a1of the plate-like portion2a.

A central guide block2his formed on a side surface of the central coupling vertical rib2epositioned outside the central space portion A1, and is coupled to the outer surface2a1of the plate-like portion2aand the upper surface of the upper horizontal rib2d. A guiding through-hole H1is drilled in the central guide block2hand the central coupling vertical rib2e. The guiding through-hole H1is composed of a vertically long main guide insertion portion h1formed in contact with the outer surface2a1of the plate-like portion2a, and a driven pin insertion portion h2formed in a central portion of a vertical surface of the main guide insertion portion h1which lies opposite the outer surface2a1of the plate-like portion2a.

2iis an intermediate horizontal rib formed between the upper-end horizontal rib2band the upper horizontal rib2d, and extending along a terminal vertical side of the plate-like portion2afrom the central guide block2hto a vertically long, terminal vertical rib2jformed perpendicularly to the plate-like portion2a. Furthermore, a terminal guide block2kis formed on an outer side surface of the terminal vertical rib2ipositioned between the paired fitting projecting portions2c1included in the long side wall-side engaging member2c. A guiding through-hole H1similar to that drilled in the central guide block2hand the central coupling vertical rib2eas described above is drilled in the terminal guide block2kand the terminal vertical rib2j.

2mand2nare intermediate guide blocks formed between the central guide block2hand the terminal guide block2kto couple the intermediate horizontal rib2iand the upper horizontal rib2dtogether. A guiding through-hole H1similar to that drilled in the central guide block2hand the central coupling vertical rib2eas described above is drilled in the intermediate guide blocks2m,2n. The number of intermediate guide blocks formed may be one or three or more.

2pis a plate-like coupling plate coupling the tip of the intermediate horizontal rib2iand the tip of the upper-end horizontal rib2bwhich are positioned between the intermediate horizontal rib2mand the central guide block2hto the tip of the central coupling vertical rib2e. Furthermore,2qis a space portion formed in the upper portion and front surface of the central guide block2hin order to reduce the weight of the container and to save materials.

Now, a lock member L1composed of an operation portion L1aand a pair of lock bars L1bwill be described with reference toFIGS. 5 to 9.

First, the operation portion L1awill be described mainly with reference toFIGS. 6 and 7.

The operation portion L1ais composed of a horizontally long operation main body10and cam portions11connected to opposite-end vertical side surfaces of the operation main body10. The operation main body10has a bar-like upper-end horizontal beam10a, a band-like lower-end horizontal beam10b, and a vertical end walls10clocated at the opposite ends thereof. The upper-end horizontal beam10aand the lower-end horizontal beam10bare coupled together by a coupling inclined wall10d. A rear surface (which, when the lock member L1is attached to the long side wall2, is positioned on the plate-like portion2aside)10d1is formed as an inclined surface which, when the lock member L1is attached to the long side wall2, extends from the upper-end horizontal beam10atoward the lower-end horizontal beam10band gradually toward the plate-like portion2aof the long side wall2.

The following are configured to be flush with one another: a vertical tip surface (which, when the lock member L1is attached to the long side wall2, is positioned farther from the plate-like portion2a)10a1of the upper-end horizontal beam10a, a vertical tip surface (which, when the lock member L1is attached to the long side wall2A, is positioned farther from the plate-like portion2a)10b1of the lower-end horizontal beam10b, and opposite vertical tip surfaces (which, when the lock member L1is attached to the long side wall2A, are positioned farther from the plate-like portion2a)10c1of the vertical-end wall10c. In this configuration, an operation space portion A2is formed in the front surface (which, when the lock member L1is attached to the long side wall2A, is positioned farther from the plate-like portion2a) of the operation main body10so that the operator's finger can be inserted into the operation space portion A2. An intermediate reinforcing wall10ecoupling the coupling inclined wall10dand the lower-end horizontal beam10btogether may be formed midway between the opposite vertical end walls10cas required to partition the operation space portion A2.

A cam portion11connected to the vertical end wall10cof the operation main body10has a segment member11aextending from the vertical tip surface10c1of the vertical end wall10cto a vertical rear surface (which, when the lock member L1is attached to the long side wall2A, is positioned on the plate-like portion2aside)10c2of the vertical end wall10c, and shaped like a substantial quarter of a cylinder. The segment member11ais bent upward from the vertical tip surface10c1toward the vertical rear surface10c2of the vertical end wall10c. Furthermore, an inclined surface11binclined downward toward the vertical end wall10cis formed on the vertical end wall10cside of the segment member11a. A partitioning wall11cparallel to the vertical end wall10cis formed in a substantial boundary area between the segment member11aand the inclined surface11b, and on an inner peripheral surface (which, when the lock member L1is attached to the long side wall2A, is positioned on the plate-like portion2aside)11a2of the segment member11a.

A cam groove12A is formed in the inner peripheral surface11a2so as to extend from a lower end11a3toward an upper end11a4of the segment member11aand gradually toward the partitioning wall11c. Furthermore, a pivotal shaft13is projected from an outer wall surface (a side surface positioned opposite the operation main body10)11c1of the partitioning wall11c.

Additionally, a pair of downward-inclined flat-plate-like spring members S1is provided on the bottom surface of the lower-end horizontal beam10bso as to hang from the vicinities of the respective ends of the lower-end horizontal beam10btoward the central portion of the lower-end horizontal beam10b.

Now, the lock bar L1bwill be described mainly with reference toFIGS. 8 and 9.

The lock bar L1bhas a horizontally long bar-like member20. A driven pin20cfitted into a cam groove12A formed in an inner peripheral surface11a2of the segment member11aof the above-described operation portion L1ais projected from a portion of a front plate (a horizontally long band-like plate which, when the lock member L1is attached to the long side wall2, is positioned farther from the plate-like portion2a)20aof the bar-like member20. A diven pin20cis positioned near one of opposite side walls20b.

The weight of the bar-like member20and the amount of material for the bar-like member20can be reduced by constructing the bar-like member20using the front plate20a, an upper-end horizontal rib20dextending in a horizontal direction from the upper end of the front plate20a, and a lower-end horizontal rib20eextending in the horizontal direction from the lower end of the front plate20a. A space portion A3is formed on a surface of the bar-like member20(which, when the block bar L1bis attached to the long side wall2A, positioned on the plate-like portion2aside) which is positioned on the plate-like portion2aside. Furthermore, to reinforce the bar-like member20, a vertical rib20for a horizontal rib20gmay be appropriately formed in the space portion A3.

Now, with reference toFIGS. 10 to 13, a description will be given of how the lock member L1composed of the operation portion L1aand the pair of lock bars L1bis assembled to the long side wall2A.

First, as shown inFIG. 10, the lock member L1is placed such that the coupling inclined wall10dformed in the operation portion L1alies opposite the outer surface2a1of the plate-like portion2aforming the central space portion A1formed in the long side wall2A. Furthermore, each of the paired lock bars L1bis placed on the side of the corresponding long side wall-side engaging member2cof the long side wall2A. At this time, the driven pin20cformed in the lock bar L1bis positioned on the long side wall2A side.

Then, each of the lock bars L1bis moved in the horizontal direction toward the corresponding long side wall-side engaging member2cformed on the long side wall2A so as to direct the driven20cof the lock bar L1bto the long side wall-side engaging member2c. The lock bar L1bis thus inserted through the guiding through-holes H1drilled in the terminal guide block2kand terminal vertical rib2jformed on the long side wall2A, and the guiding through-holes H1drilled in the intermediate guide blocks2m,2n, and through the guiding through-hole H1drilled in the central guide block2hand the central coupling vertical rib2e. Thus, as shown inFIG. 11, the driven pin20cof the lock bar L1bis positioned in the central space portion A1formed in the long side wall2A and close to the pivotal shaft supporting block2g. When the lock bar L1bis inserted through the guiding through-holes H1, the bar-like member20of the lock bar L1bis inserted through the main guide insertion portion h1. Furthermore, the driven pin20cof the lock bar L1bis inserted through the driven pin insertion portion h2.

Then, the operation portion L1ais moved closer to the plate-like portion2aforming the central space portion A1formed in the long side wall2A. Thus, the pivotal shaft13of the operation portion L1ais allowed to abut against the guiding inclined surface2g2formed on the pivotal shaft supporting block2gformed on the plate-like portion2aof the long side wall2A. Moreover, the operation portion L1ais moved closer to the plate-like portion2aof the long side wall2A. Then, the pivotal shaft13of the operation portion L1amoves closer to the plate-like portion2aof the long side wall2A while being guided along the guiding inclined surface2g2of the shaft pivotal-supporting block2g. Finally, the pivotal shaft13of the operation portion L1ais fitted into the bearing holes2g3in the respective pivotal shaft bearing blocks2g. Furthermore, the driven pin20con the lock bar L1bis inserted into the lower end of the cam groove12A formed in the inner peripheral surface11a2of the segment member11aof the operation portion L1a. In this manner, as shown inFIG. 13, the lock member L1is assembled to the long side wall2A. When the lock member L1is assembled to the long side wall2A, the tip s1of each of the spring members S1formed on the operation portion L1aapproaches or abuts against the top surface of the upper horizontal rib2dpositioned in the central space portion A1.

As described above, with the lock member L1assembled to the long side wall2A, a tip portion of the lock bar L1bprojects beyond the terminal guide block2kof the long side wall2A as shown inFIG. 13, and the tip portion of the lock bar L1bis positioned between the paired fitting projecting portions2c1formed in the long side wall-side engaging member2c. The end side wall20bforming the tip of the lock bar L1bis configured so as not to project beyond the long side wall2A. This state of the lock member L1is hereinafter referred to as the lock state of the lock member L1.

Now, the operation of the lock member L1assembled to the long side wall2A will be described with reference toFIGS. 14 to 17.

When the folding container is in the assembled box form as shown inFIG. 1, the lock member L1is in the lock state. In this state, the tip portion of the lock bar L1bis inserted in the engaging recess portion3eformed in the short side wall-side engaging member3cof the short side wall3A as shown inFIG. 14. Furthermore, the fitting projecting portions2c1formed on the long side wall-side engaging member2cof the long side wall2A are fitted in the corresponding fitting holes3fformed in the short side wall-side engaging member3cof the short side wall3A. Thus, the long side wall2A is prevented from falling down toward the bottom portion1unless the lock state of the lock member L1is cancelled as described below.

To fold the folding container assembled in the box form, the operator inserts the operator's finger in the operation space portion A2of the operation portion L1aof the lock member L1in the lock state as shown inFIGS. 12 and 13, and then pushes the lower-end horizontal beam10bof the operation portion L1adownward. Then, the lower-end horizontal beam10bof the operation portion L1ais pivotally moved closer to the upper horizontal rib2d, using, as a pivotal point, the pivotal shaft13of the operation portion L1afitted in the bearing holes2g3in the pivotal shaft supporting block2gformed on the long side wall2A (this pivotal moving direction is hereinafter simply referred to as the downward pivotal movement of the operation portion L1a). The downward pivotal movement of the operation portion L1acauses the spring members S1formed on the operation portion L1ato be compressed against the elastic force thereof as shown inFIG. 16(the following is hereinafter referred to as the compressed state of the spring member S1: the state in which the tip s1of each of the spring members S1is located close to the lower-end horizontal beam10bof the operation portion L1a).

As described above, the downward pivotal movement of the operation portion L1aallows the driven pin20cof each of the lock bars L1binserted in the lower end of the corresponding cam groove12A formed in the operation portion L1ato move to the upper end of the cam groove12A. Thus, the paired lock bars L1bmove closer to each other.

As described above, when the operation portion L1ais pivotally moved downward to move the paired lock bars L1bcloser to each other, the tip portion of the lock bar L1binserted in the engaging recess portion3eformed in the short side wall-side engaging member3cof the short side wall3A is removed from the engaging recess portion3eas shown inFIG. 17. Thus, with the folding container assembled in the box form, the lock state in which the lock member L1of the long side wall2A locks the short side wall3A is cancelled to allow the long side wall2A to be brought down toward the bottom portion1. Then, the short side wall3A is brought down toward the bottom portion1to allow the folding container to be folded.

As described above, when the lock state established between the long side wall2A and the short side wall3A via the lock member L1is cancelled, the upper-end horizontal beam10aof the operation portion L1ais pivotally moved closer to the upper-end horizontal rib2bby the elastic restoring force of the spring members S1, the pivotal shaft13of the operation portion L1afitted in the bearing holes2g3in the pivotal shaft supporting block2gformed on the long side wall2A (this pivotal moving direction is hereinafter simply referred to as the upward pivotal movement of the operation portion L1a).

As described above, the locking and unlocking between the long side wall2A and the short side wall3A via the lock member L1is performed by pivotally moving the operation portion L1adownward (the unlocking between the long side wall2A and the short side wall3A) or upward (locking between the long side wall2A and the short side wall3A) using, as a pivotal point, the pivotal shaft13of the operation portion L1afitted in the bearing holes2g3in the pivotal shaft supporting block2gformed on the long side wall2A. Thus, even if the operator pushes a part of the lower-end horizontal beam10bof the operation portion L1awhich the part is positioned on the vertical-end wall10cside, the operation portion L1ais prevented from being tilted. Therefore, the pair of lock bars L1bmoved backward (toward the central portion of the long side wall2A) by the downward pivotal movement of the operation portion L1ais simultaneously and reliably moved in the horizontal direction. Thus, the long side wall-side engaging members2carranged at the respective ends of the long side wall2A can be reliably unlocked from the short side wall-side engaging members3carranged at the respective ends of the short side wall3A via the lock member L1. This enables the solution of the problem with the conventional folding container that one of the lock bars L1bfails to be removed from the engaging recess portion3eof the corresponding short side wall-side engaging members3cof the short side wall3A, preventing the long side wall2A from being brought down toward the bottom portion1.

Furthermore, even when the elastic restoring force of the spring members S1causes the operation portion L1ato move pivotally upward, the pair of lock bars L1bmoved forward (toward the terminal vertical rib2jof the long side wall2A) by the upward pivotal movement of the operation portion L1ais simultaneously and reliably moved.

Now, another embodiment of the present invention will be described with reference toFIGS. 18 to 21.

The present embodiment uses coil-like spring members (hereinafter simply referred to as coil springs) instead of the flat plate-like spring members S1hanging from the bottom surface of the lower-end horizontal beam10bof the operation main body10included in the operation portion L1ain the above-described embodiment. Furthermore, in order to allow such coil springs S2to be used, the operation portion L1ais modified as follows.

As shown inFIG. 19, in the present embodiment, as described above, the flat plate-like spring members S1are omitted which hang from the lower-end horizontal beam10bof the operation main body10included in the operation portion L1ain the above-described embodiment. In the present embodiment, a coil spring supporting plate14is formed in a corner portion formed by the partitioning wall11cand the lower-end horizontal beam10bof the operation main body10. Furthermore, a coil spring supporting pin14ais projected from a rear surface (which, when the lock member L1is attached to the long side wall2A, is positioned on the plate-like portion2aside) of the coil supporting plate14so that one end of the coil spring S2can be inserted around the coil spring supporting pin14a.

As shown inFIG. 18, one end of the coil spring S2is inserted around the coil spring supporting pin14a. Then, as in the above-described embodiment, the operation portion L1aincluded in the lock member L1is placed opposite the outer surface2a1of the plate-like portion2aof the long side wall2A. Thereafter, the operation portion L1ais moved closer to the long side wall2A and thus assembled to the long side wall2A as in the case of the above-described embodiment.

As shown inFIG. 20, with the lock member L1in the lock state, the coil springs S2are expanded. Furthermore, when the operation portion L1ais pivotally moved downward for unlocking, the coil springs S2are compressed as shown inFIG. 21. When the operator takes the operator's hand off the operation portion L1a, the operation portion L1ais pivotally moved upward by the restoration force of the coil springs S2.

Now, another embodiment of the present invention will be described with reference toFIGS. 22 to 24.

In the above-described embodiments, as shown inFIG. 7, the cam groove12A formed in the inner peripheral surface11a2of the segment member11aincluded in the lock member L1extends from the lower end11a3to upper end11a4of the segment member11aand gradually toward the partitioning wall11c. However, in the present embodiment, a cam groove12B is formed so as to extend from the lower end11a3to upper end11a4of the segment member11aand gradually away from the partitioning wall11c.

Furthermore, when the operation portion L1ais pivotally moved upward, the driven pin20cof the lock bar L1bincluded in the lock member L1is inserted into the lower end of the cam grove12B. In this state, when the operation portion L1ais pivotally moved downward, the driven pin20cof the lock bar L1bis moved to the upper end of the cam groove12B. Thus, the paired lock bars L1bmove away from each other.

As shown inFIG. 23, this folding container is applicable to a folding container of a type in which an elastic piece E1having a projecting portion e1projected therefrom is formed on the plate-like portion3aof the short side wall3B. Since a folding container of this type is well known (for example, the Unexamined Japanese Patent Application Publication (Tokkai) No. 2004-51199), the configuration of the folding container itself is omitted.

As shown inFIG. 23, with the operation portion L1apivotally moved upward (lock state), the paired lock bars L1bare prevented from abutting against the elastic piece E1. Furthermore, with the operation portion L1apivotally moved downward, the paired lock bars L1bmove away from each other to allow the end side wall20bforming the tip of the lock bar L1bto abut against the projecting portion e1of the elastic piece E1. Thus, as shown inFIG. 24, the elastic piece E1is elastically deformed outward, thus in the folding container assembled in the box form, unlocking, from the elastic piece E1, a locking piece (not shown in the drawings) formed on the long side wall-side engaging member2cof the long side wall2A placed between the short side wall-side engaging member3cof the short side wall3B and the projecting portion e1of the elastic piece E1. As a result, the long side wall2A can fall down to the bottom portion1.

Now, yet another embodiment will be described with reference toFIGS. 25 to 29.

The long side wall2B has a plate-like portion200asimilar to the plate-like portion2ain the above-described embodiment. An upper-end horizontal rib200bsimilar to the upper-end horizontal rib2bin the above-described embodiment is formed at the upper end of the long side wall2B. Furthermore, a long side wall-side engaging member200cis formed at each of the opposite vertical ends of the long side wall2B so as to extend in the direction of the plate-like portion200aand outward from a terminal vertical rib200jsimilar to the terminal vertical rib2jin the above-described embodiment. Fitting projecting portions200c1are formed at the upper end of the long side wall-side engaging member200cat a predetermined distance from each other and substantially perpendicularly to the plate-like portion200aso as to extend toward an outer surface (which, when the folding container is assembled into a box form, is positioned outside the assembled folding container)200a1of the plate-like portion200a. Moreover, an upper horizontal rib200dis formed on the upper portion of the plate-like portion200aat a predetermined distance from the upper-end horizontal rib200bso as to connect the terminal vertical ribs200jtogether.

Paired opposite central coupling vertical ribs200eare formed at a predetermined distance from each other so as to couple a central area of the upper-end horizontal rib200band a central area of the upper horizontal rib200dtogether. A central space portion A10is formed by the upper-end horizontal rib200b, the upper horizontal rib200d, the opposite paired central coupling vertical ribs200e, and the outer surface200a1of the plate-like portion200a.

A lever slit200e1serving as a lever support point for a lock bar L100bincluded in a lock bar L100described below is drilled in the central coupling vertical rib200e.

Furthermore, intermediate-end-side coupling vertical ribs200mcoupling the upper-end horizontal rib200band the upper horizontal rib200dtogether is formed closer to the respective terminal vertical ribs200jthan the corresponding central coupling vertical ribs200e. A slit200m1is drilled in each of the intermediate end-side coupling vertical ribs200mso that the lock bar L100bincluded in the lock member L100described below can be moved through the slit200m1in the vertical direction.

Moreover, a slit200j1is also drilled at the upper end of the terminal vertical rib200jso that the lock bar L100bincluded in the lock member L100described below can be moved through the slit200j1in the vertical direction.

Now, the lock member L100composed of the operation portion L100aand the lock bar L100bwill be described with reference toFIGS. 26 and 27.

The operation portion L100ahas a rectangular plate-like base portion100a, and paired operation bars100bprovided on the bottom surface of the plate-like base portion100aalong a long-side end surface10a1of the plate-like base portion100aand at a predetermined distance from each other so as to extend in the vertical direction. The operation bar100bhas a columnar portion100b1connected to the bottom surface of the plate-like base portion100a, and a spherical operation end100b2formed at the tip of the columnar portion100b1. The outer diameter of the operation end100b2is formed to be larger than the thickness of the columnar portion100b1. Furthermore, a pivotal shaft100a3is projected from opposite short-side end surface100a2of the plate-like base portion100a.

The lock bar L100bis composed of a flat prismatic block base portion100c, and a vertical, flat plate-like plate portion100dcoupled to one of opposite vertical surfaces100c1of the block base portion100c. Furthermore, a plate-like spring member S10inclined toward the plate portion100dhangs from the bottom surface of each of the block base portions100c.

A cam groove100eis formed in the upper portion of each of the block base portion100cat a position located opposite the operation plate portion100d, so as to extend from one of opposite long-side vertical surfaces100c2of the block base portion100ctoward the other long-side vertical surface100c2but not to reach the other long-side vertical surface100c2. The cam groove100eis formed parallel to the short-side vertical surface100c1of the block base portion100c.

As shown inFIG. 27, the cam groove100eis composed an operation end fitting portion100e2formed in the lower portion of the cam groove100eand in which the operation end100b2of the operation bar100bcan be fitted, and a columnar fitting portion100e1in which the columnar portion100b1of the operation bar100bis fitted and guided. The cam groove100eis formed so as to appear a reversed T-shape as viewed from the long-side vertical surface100c2.

Support pieces200fare provided in a central region of the bottom surface of the upper-end horizontal rib200bof the long side wall2B at a predetermined distance from each other so as to hang therefrom orthogonally to the longitudinal direction of the upper-end horizontal rib200b. A pivotal-supporting hole200f1is formed in each of the support pieces200fso that the pivotal shaft100a3projected from the above-described operation portion L100ais fitted and pivotally supported in the pivotal-supporting hole200f1.

To assemble the lock member L100to the long side wall2B, the plate portion100dof the lock bar L100bis inserted, from the central coupling vertical rib200eside, firstly through the lever slit200e1drilled in the central coupling vertical rib200e. The plate portion100dis thereafter inserted through the slit200m1drilled in the intermediate-end coupling vertical rib200m. The plate portion100dis further inserted through the slit200j1drilled in the terminal vertical rib200j. Thus, the plate portion100dis inserted through the lever slit200e1drilled in the central coupling vertical rib200e, also through the slit200m1drilled in the intermediate-end coupling vertical rib200m, and further through the slit200j1drilled in the terminal vertical rib200j. Then, the block base portions100cof the paired lock bar L100bare arranged in the central space portion A10formed by the upper-end horizontal rib200b, the upper horizontal rib200d, the opposite paired central coupling vertical ribs200e, and the outer surface200a1of the plate-like portion200a. In this state, the tip of the each of the spring members S10abuts against or is positioned close to the upper horizontal rib200d.

Then, the operation portion L100ais moved closer to the outer surface200a1of the plate-like portion200of the long side wall2B. Thus, the operation end100b2of the operation bar100bis inserted into the operation end fitting portion100e2of the cam groove100e. Furthermore, the columnar portion100b1of the operation bar100bis inserted into the columnar fitting portion100e1of the cam groove100e. Thus, the lock member L100is assembled to the long side wall2B. As described above, when the lock member L100is assembled to the long side wall2B, the operation bar100bof the operation portion L100ais positioned in an opening side of the cam groove100e. Furthermore, the pivotal shaft100a3projected from the opposite short-side end surfaces100a2of the plate-like base portions100aof the operation portion L100ais fitted into the pivotal-supporting holes200f1formed in the opposite surfaces of the support pieces200fprovided on the bottom surface of the upper-end horizontal rib200bof the long side wall2B at the predetermined intervals from each other so as to hang downward.

As described above, when the lock member L100is assembled to the long side wall2B, the operation end100b2of each of the lock bars L100babuts against or is positioned close to the bottom surface100e1′ of the operation end fitting portion100e2of the cam groove100e. Furthermore, as shown inFIGS. 25 and 28, the plate portions100dof the lock bar L100bare horizontally held. In this state, the tip of each of the spring members S10abuts against or is positioned close to the upper horizontal rib200d.

The above-described state is the lock state in which each of the lock bars L100bof the lock member L100is locked in the locking portion (not shown in the drawings) formed in the short wall-side engaging member3cof the short side wall3A.

To cancel the lock state between the long side wall2B and the short side wall3A by the lock member L100, the operation portion L100aof the lock member L100which is positioned in upward state (lock state) is pivotally moved downward using, as a pivotal point, the pivotal-supporting holes200f1formed in the support pieces200fand the pivotal shaft100a3of the operation portion L100afitted into the pivotal-supporting holes200f1.

As described above, when the operation portion L100aof the lock member L100is moved downward, the operation bars100bof the operation portion L100amove toward the plate-like portion2aof the long side wall2B. Then, as shown inFIG. 29, the tip portion of each of the lock bars L100bmoves upward using, as a lever support point, the horizontal lower end forming the lever slit200e1drilled in the central coupling vertical rib200eand serving as a lever support point.

As described above, moving the tip portion of each of the lock bars L100bupward allows cancellation of the lock state between the locking piece (not shown in the drawings) formed on the short side wall-side engaging member3cof the short side wall3A and the lock bar L100battached to the long side wall2B. Thus, the long side wall2B falls down toward the bottom portion1. This type of folding container is well known (see, for example, the Unexamined Japanese Patent Application Publication (Tokkai) No. 2003-40263).

The embodiment shown inFIG. 30corresponds to the above-described embodiment in which the paired lock bars L100bare integrated into the appropriate components. In this configuration, pivotally moving the operation portion L100adownward allows the lock bars L100bto lower while remaining parallel to the upper horizontal rib200d. Thus, a slit200e2is drilled in each of the central coupling vertical ribs200eso that the corresponding lock bar L100bcan move up and down through the slit200e2; the slit200e2is similar to the slit200m1formed in the intermediate end-side coupling vertical rib200mand the slit200j1formed in the terminal vertical rib200j.

In the configuration of the above-described embodiment, the long side wall2A and the short side wall3A are unlocked by pivotally moving the operation portions L1a, L100adownward. The long side wall2A and the short side wall3A are locked by pivotally moving the operation portions L1a, L100aupward. However, in an alternative configuration, the long side wall2A and the short side wall3A may be unlocked by pivotally moving the operation portions L1a, L100aupward, and the long side wall2A and the short side wall3A may be locked by pivotally moving the operation portions L1a, L100adownward.