CAP WITH RESILIENTLY REVERSING LID

Abstract: A cap or the like having a resiliently reversing lid, in which the top surface of an outer first peripheral wall (2) of a cap (1) or the like is closed with a lid (5) having a second peripheral wall (7) suspending from the outer periphery of a top wall (6) in such manner that the lower end surface of the second peripheral wall (7) rides on the upper end surface of said first peripheral wall; the upper and lower ends of rear surfaces of the first and second peripheral walls (2, 7) respectively, are connected to each other with a hinge (10) and, in addition to said hinge, the rear upper and lower parts of the first peripheral wall (1) are connected to each other with a resilient band plate (12), so that the lid (5) may be opened or closed around said hinge (10); and said hinge (10) is positioned farther back than said resilient band plate and formed into one body with the cap from synthetic resin; and a main object of the invention is to leave none of cutaway part as a trace used to remain in many cases on the lid after removal of the metallic mold when integrally molding a cap of such kind as above from synthetic resin.

Description: The present invention relates to a snap-type cap structure according to the pre-characterizing part of claim 1. The "cap structure" used herein is meant to include a cap and a container with a cap. There is known a cap which is integrally molded of a synthetic resin. The cap body is hingededly connected to the cover at three points, (Japanese Utility Model Laid-Open No. 34049/1988). This three-point hinge structure comprises: first two hinges for connecting the upper end of the rear portion of the circumferential wall of the cap body and the lower end of the rear portion of the circumferential wail of the cover placed on the cap body; and second and third hinges for connecting L-shaped elastic plates between the first circumferential wall portion below the first hinges and the front portion of the top wall of the cover at the upper end of the circumferential wall portion of the cover between the two hinges. In order that the three-point hinged cap may be integrally molded of a synthetic resin, both the circumferential wall portion of the cover in front of the rising portions of the L-shaped elastic plates and the top wall portion of the cover below the horizontal portion are notched for parting the mold. Especially, the notched portions of the top wall of the cover deteriorate the appearance of the cover. Still worse, the notches disable a complete shut off of the mouth of the cap body with the cover. In accordance with the pre-characterizing part of claim 1, EP-A-0 291 457 discloses a snap-type cap structure, wherein two webs are provided on the both sides of the elastic band. The ends of the webs are attached within recesses provided within the body as well as within the cover. The webs are responsable for a pre-load tending to move the cover into the closed position. GB-A-2 224 309 discloses a snap-type cap structure, wherein a first flexible web defines a first hinge axis, while an additional flexible member is provided to obtain a toggle action, the additional flexible member is formed by extending the top surface of the cover member. The first hinge axis is defined by the ends of two protrusions provided on the body and the cover, respectively. FR-A-2 633 590 discloses a snap-type cap structure wherein the body and the cover are connected by means of two hinges between which there is provided an elastic member. A simular structure is shown in FR-A1-0 345 403. The structure disclosed in each of these two documents is such that the hinges form protrusions, which deteriorate the appearance of the article. EP-A1-0 385 078 discloses a snap-type cap structure in which an elastic band is provided between a pair of hinges, wherein the elastic band is flush with the outer surface of the body and the cover when the cover is in its closed position. It is the object of the present invention to provide for a snap-type cap structure of the above mentioned type having an improved appearance and a long lifetime. This object is achieved in accordance with the features of the characterizing part of claim 1. Figs. 1 to 5 show one embodiment of the cap structure of the present invention; Fig. 1 is a perspective view showing the open state; Fig. 2 is a perspective view showing the closed state from the back; Fig. 3 is a top plan view showing the same; Fig. 4 is an enlarged section showing an essential portion; and Fig. 5 is an enlarged section showing an essential portion in the open state. Reference numeral 1 designates the body of a cap structure having a first circumferential wall 2. This first circumferential wall 2 is formed into a circumferential wall to be fitted on the outer circumference of the neck of a container, in case the body 1 is a cap, and has its lower end shut out with a bottom wall in case the cap structure is a container body. In the shown embodiment, the first circumferential wall has its top covered with a top plate 4 having a pouring port 3, but this top plate 4 can be eliminated. Indicated at reference numeral 5 is a cover which is molded of polyethylene or the like integrally with the aforementioned body 1. This cover 5 can be turned on later-described hinges to open or close the top of the first circumference. In the cover 5, a second circumferential wall 7 depends from the outer circumference of a top wall 6 and can have its lower end placed on the upper end of the first circumferential wall 2. The first circumferential wall 2 and the second circumferential wall 7 are shaped into a true circle, as seen in a top plan view. and have their backs formed into a vertical wall 8 which in turn is formed with a groove 9 at its widthwise center. The vertical walls of the first and second circumferential walls 2 and 7, which are divided by the groove, have their respective upper and lower ends connected by curved hinges 10 and 10, as better seen from Fig. 4. Moreover, the upper end of the groove bottom of the first circumferential wall and the lower end of the groove bottom of the second circumferential wall are formed to merge into each other, and the first and second circumferential wall portions are formed in front of their merging portions with holes 11 and 11, which are extended downward and upward from the upper and lower ends of the individual circumferential walls to leave an elastic band 12 at the bottom of the groove 9 at the back of the holes 11 and 11. This elastic band 12 is preliminary curved such that the body 1 and the cover 5 are integrally molded of a synthetic resin such as polyethylene, as shown in Fig. 5 with the cover 5 being opened with respect to the body 1 and with the elastic band 12 being curved upward. The connecting portions between the upper and lower ends of the elastic band and the second and first circumferential walls are so formed that they cannot be bent angularly. In case of an embodiment shown in Fig. 1 to 5, if a cover 5 is pushed up from the open state of Fig. 5, each of curved elastic bands 12 is to have its cover side end 12b moved along an arc a , which has a radius of a straight distance from the body side end 12a to the cover side end 12b of the elastic band 12. Since, however, the cover 5 is turned on hinges 10, it is allowed to move along an arc b which has a radius of a straight distance from the hings 10 to the cover side end 12b. If the pint of intersection between a straight line c containing the body side end 12a and the hinges 10 and the aforementioned arc b is designated at a dead center A, the elastic band 12 is extended till the dead center A against its elasticity and is shrunken after the dead center A by its elastic controlling force so that the cover is elastically turned over to establish the closed state. The cover opening operation could be likewise understood. Incidentally, the elastic band 12 may have its intermediate portion curved to the fron in the closed state of Fig. 4.

Claims: A snap-type cap structure made of synthetic resin comprising: a body (1) having a first circumferential wall (2), a cover (5) having a second circumferential wall (7) which is placed on the first circumferential wall (2), said first and second circumferential walls being connected by a pair of hinges (10), and an elastic band (12) connecting the body (1) to the cover (5); characterized in that said first and second circumferential walls (2, 7) each having a vertically extending plane wall portion (8) at one side thereof, and a groove (9) extending vertically at the widthwise center of said vertically extending plane wall portions, wherein said vertically extending wall portions meet each other and are connected by said hinges (10) at both sides of said groove, the bottom wall of said groove mergeing into said elastic band (12). A cap structure in accordance with claim 1, wherein the bottom wall of the groove (9) is provided at inner parts thereof with holes (11), which extend vertically along said groove, such that the elastic band (12) is formed outside of said holes (11). A cap structure in accordance with claim 1 or 2, wherein the body is adapted to be secured to an open mouth of a container. A cap structure in accordance with claim 1 or 2, wherein the body is a container having the first circumferential wall (2) forming an open mouth.

Inventors: NOZAWA TAKAMITSU - KAMIOGI -CH, TASAKI TAKAHARU YOSHINO KOGYOS, NOZAWA, TAKAMITSU, 17-10, KAMIOGI 2-CHOME, TASAKI, TAKAHARU, YOSHINO KOGYOSHO CO., LTD.
Applicants: YOSHINO KOGYOSHO CO LTD, YOSHINO KOGYOSHO CO., LTD.
Application year: 1991
Main classification: B65D47
IPC codes: B65D47