Lower joint folding preventing device for one touch type dome shaped tent

Abstract: A lower joint folding preventing device for a one touch type dome shaped tent is disclosed. If the upper joint is locked or released, the lower joint is also locked or released automatically. A connecting portion (14) of the lower joint is provided with a round projection (15) and with an elongate slot (16), and the middle segment (B) is provided with a socket (10) and a supporting step (13), in such a manner that the round projection (15) can be mounted upon the supporting step (13). Further, a coil spring (19) is installed on the neck portion (20) of the lower segment (C) so that the leading end of the coil spring (19) should able to push the tip of the socket (10).

Description: Field of the invention The present invention relates to a lower joint folding preventing device for a one touch type dome shaped tent in which the folding portions can be conveniently folded and spread like the usual automatic umbrellas. Particularly the present invention relates to a lower joint folding preventing device for a one touch type dome shaped tent in which, if the tent is spread, the upper joints and the lower joints are locked simultaneously, and, as long as the tent is not folded, the lower joints are not folded but will maintain the spread state under any external forces applied, while, if the upper joints are folded in order to fold up the tent, the lower joints are folded in a spontaneous manner. Background of the invention The conventional one touch type dome shaped tent (DE-A-3 631 381) is illustrated in Figures 1 to 3, and the structure shown in these drawings is the basis for applying the device of the present invention. Figure 1 is a perspective view showing the structure of the spread state of the conventional one touch type dome shaped tent. As shown in this drawing, frame members 2 are joined to a hub 1 of the central peak of the tent, and the frame members 2 extent in all directions from the hub 1, thus the hub 1 forming an easily foldable central joint. Each of the frame members 2 consists of an upper segment A, a middle segment B and a lower segment C, and the three segments are joined into an integrated member, while each of the joining portions is provided with a hinge. Among the three segments, the upper segment A and the middle segment B are joined at an upper joint 3 in the form of ∧, while the middle segment B and the lower segment C are connected at a lower joint 4 in the form of V. Thus the upper and lower joints 3,4 perform folding movements in mutually opposite directions, in such a manner that one whole frame member 2 should form a zig-zag shape, as shown in Figure 3. Further, the upper joint 3 is provided with a locking cap 5, so that an end portion 6 of the joint should be secured, and that an inadvertant folding should be prevented as shown in Figure 2. If the locking cap 5 is pushed down, the locked state is released, so that the upper joint 3 can be folded in the form of ∧. In contrast to.this, the lower joint 4 is provided with no such a locking device, but is provided with only a pivotal structure. But an end portion 7 of the joint is let to support the lower segment C, so that the lower segment C can be folded only outwardly. Thus if the tent is spread, the frame members are bent like a bow as shown in Figure 2, while if the tent is folded, the frame members are folded in the form of V. However, it has been proved through experience that the conventional one touch type dome shaped tent having the above described structure has problems yet to be solved. That is, there is no locking device on the lower joint 4, and therefore, if a slight pushing force is applied, with the tent being spread, the lower joint 4 can be inwardly folded as shown by an imaginary line S of Figure 2, thereby making the tent collapsed. Examples of such external forces T are an abrupt wild wind, intrusion of a playing children, kicking by a nocturnal walker, and the like. In an attempt to overcome the above described problems, a locking device may be provided also to the lower joint 4. However, in such a case, there appears the problem that the upper and lower locking devices have to be operated one by one with hand. Such a matter hurts the originally intended feature of the one touch type dome shaped tent which aims at the convenience and speediness of the folding operation. If one manipulation of the upper joint 3 causes the lower joint 4 to be operated (locked or released), it will be satisfactory, but so far, such a device has not been invented. GB-A-599.210 describes a tube joint which permits the jointed tubes to be moved angularly to each other or to be retained in alignment as desired. This tube joint comprises two joint members for insertion to the ends of the tubes to be jointed, one of these joint members having a pin which engages in a slot in the other joint member while co-acting locking surfaces are formed on the joint members for holding the tubes in aligned position. A compression spring is housed within one of the tube to be connected in order to hold the locking parts in resilient engagement and then disengagement is effected against the action of that spring. With this kind of joint tubes can be moved angularly to each other in all side or to be retained in alignment as desired but it cannot be used to fold the segments of the frame members of the structure of one touch type dome shaped tent, in particular to fold the lower segment which must be folded only outwardly or maintained heavily aligned with the middle segment ; further more to have the locking parts of this joint engaged or disengaged, it is necessary to use two hands ; now in a one touch type dome shaped tent, if the upper joints are locked or released, the lower joints must be also locked or released automatically. Another problem lies in the joining between the joint and the frame member. That is, conventionally, the hole of the joint portion has a circular cross section, and the frame member has also a circular cross section. Therefore, even if the frame member is press-fitted into the hole of the joint portion, a clearance appears between the frame member and the hole, with the result that the frame members can be twisted, thereby brining problems to folding or spreading the tent. Summary of the invention The present invention is intended to overcome the above described disadvantages of the conventional one touch type dome shaped tent. Therefore it is the object of the present invention as characterized in the claims to provide a lower joint folding preventing device for a one touch type dome shaped tent, in which the cross sections of both the frame member and the hole of the joint portion are flattened into a straight line at some portion thereof, and a locking device is provide also to the lower joint in such a manner that both the upper and lower joints can be locked or released with only one touch manipulation. In achieving the above object, the lower frame segment which is connected to the lower joint is provided in an advancable and withdrawable manner, and the movability of the lower segment is supported by an elastic means. Brief description of the drawings The above object and other advantages of the present invention will become more apparent by describing in detail the preferred embodiment of the present invention with reference to the attached drawings in which: Figure 1 is a perspective view showing the constitution of the conventional one touch type dome shaped tent; Figure 2 illustrates the constitution of the joint and the folded state of the conventional tent; Figure 3 illustrates the folding shape of the conventional tent; Figure 4 is an exploded perspective view showing the constitution of the lower joint portion of the frame member according to the present invention; Figure 5 illustrates a state in which the locking state of the lower joint is automatically released when folding the tent; Figure 6 illustrates a state in which the lower joint portion is automatically locked when spreading the tent; Figure 7 illustrates a state in which the frame members exert forces toward the joining portions each other when the tent is spread; and Figure 8 is an enlarged sectional view showing the cross section of the line D-D of Figure 4. Description of the preferred embodiment As shown in the drawings, frame members 2 are extended in all directions, and each of the frame members 2 is provided with an upper joint 3 and a lower joint 4. The device of the present invention can be applied to the tent having the constitution of Figures 1 and 2. The lower joint 4 of the device of the present invention is provided with a socket 10 at the end of a middle segment B of the frame member 2, and the opposite walls of the socket 10 is provided with a pair of pin holes 11 as shown in Figure 4. Further, the socket 10 forms a recess 12, and,at the inner end of the recess 12, there is provided a supporting step 13. A lower frame segment C is provided with a connecting portion 14, and the connecting portion 14 is provided with a round projection 15 which is engaged with the supporting step 13 of the middle frame segment B, while the connecting portion 14 is also provided with an elongate slot 16 at a position corresponding to the pin hole 11. The connecting portion 14 of the lower segment C is coupled with the socket 10 of the middle segment B, and a pin 18 is inserted into the pin hole 11 and the elongate slot 16 after aligning them, thereby joining the two segments B,C. At the neck of the lower segment C, there is installed a coil spring 19, with the lower end of the spring 19 being supported by an annular projection 20. The leading end of the spring is fitted with a spring seat 21, and abuts to the tip of the socket 10 of the middle segment B. The connecting portion 14 can advance and withdraw within the range of the elongate slot 16, and, when the tent is spread, if the segments move closer to each other by the compressing forces of the frame member, then the coil spring 19 is compressed. Meanwhile, when the tent is folded, if the compressing forces of the frame members are released, the compressed spring exerts a restoring force, so that the middle and lower segments B,C should depart from each other, thereby making it possible to easily fold the lower segment C as shown in Figure 5. Figure 7 illustrates a state in which the upper, middle and lower segments A,B,C exert compressing forces each other toward joining portions H, using arrow marks. That is, when the tent is spread, and when the frame members are bent, the respective segments of the frame members exert forces toward the relevant joining portions H by the pulling action of the tent fabric. Owing to such a phenomenon, when the tent is spread, the middle segment B and the lower segment C are compressed toward each other as shown in Figure 6, with the result that the round projection 15 is mounted upon the supporting step 13. Under this condition, the coil spring 19 is compressed, and, owing to the two securing points, i.e., the round projection and the pin, the locking of the lower joint 4 is maintained, with the folding of the lower segment C being prevented. When the tent is kept spread continuously, the pulling action of the tent fabric continues, and therefore, the locked state of the lower joint 4 is continuously maintained. Under this condition, even if an external force is applied to the lower joint 4 or to the lower frame segment C, the lower joint can not be folded. On the other hand, if the locked state of the upper joint 3 is released in order to fold up the tent, the pulling force of the tent fabric is released, and the coil spring 19 exerts a restoring force, with the result that the two segments B,C departs from each other, thereby making it possible to fold the lower segment C in a V form. Further, the socket and the connecting parts have connecting holes with a cross section consisting of a circular arc portion and a straight chord portion to form a flat surface and the frame segments having corresponding ends portions to be fitted into said holes, the cross section of said ends portions consisting also of a circular arc portion and a straight chord portion to form a corresponding flat surface with the result that the twisting of the frame members can be prevented. According to the present invention constituted as described above, if the frame members 2 are unfolded, and thus if the upper joint 3 is locked, the lower joint 4 is also locked. Again, if the upper joint 3 is released from the locked state, the lower joint 4 is also released together. Therefore, the one touch effect remains same in the present invention as in the conventional one touch type tent, but adds another effect such that the locking or release of the lower joint 4 can be achieved with one touch manipulation, thereby giving a solution to the problem inherent to the conventional one touch type dome shaped tent.

Claims: A foldable frame for a domed shaped tent having frame members consisting of three frame segments connected by upper and lower joint means characterised in that the lower joint means ( 4 ) is provided with : a socket part ( 10 ) affixed at the end of the middle frame segment ( B ) of which the opposite walls are supplied with opposed pin holes ( 11 ) and form a recess ( 12 ) at the inner end of which is provided a supporting step ( 13 ), a connecting part ( 14 ) affixed at lower frame segment ( C ) provided with a round projection ( 15 ) and with an elongate slot ( 16 ) respectively meant to be engaged with the supporting step ( 13 ) of the socket ( 10 ) and to be coupled with the said socket ( 10 ) by a pin ( 18 ) inserted into its pin holes ( 11 ), a coil spring ( 19 ) mounted on the neck of the lower segment ( C ) of which the lower end is supported by an annular projection ( 20 ) and the leading end is fitted with a spring seat ( 21 ) and abutted on the tip of the socket ( 10 ), and wherein both the socket and the connecting parts have connecting holes with a cross section consisting of a circular arc portion and a straight chord portion to form a flat surface and the frame segments having corresponding ends portions to be fitted into said holes, the cross section of said ends portions consisting also of a circular arc portion and a straight chord portion to form a corresponding flat surface in order to prevent the twisting of the frame member ( 2 ).

Inventors: DONG SOO JU, DONG, SOO JU
Applicants: BAE JIN CORP, BAE JIN CORPORATION
Application year: 1991
Main classification: E04H15
IPC codes: E04H15