Cap with resiliently reversing lid

Abstract: Described is 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) placed on the first circumferential wall (2) and a first hinge (10) for connecting said first and second circumferential walls, and a pair of elastic bands (12) which are provided on both sides of the first hinge for connecting said first and second circumferential walls. A pair of recesses (13) each being formed by a lower recess portion on the first circumferential wall and an upper recess portion on the second circumferential wall, which are provided at positions corresponding to said elastic bands. The ends of the elastic bands (12) are connected through second and third hinges (14,15) to outer edges of the upper and lower ends of the recesses, and the elastic bands have C-shaped longitudinal sections in a closed state and an open state in which the cover is turned over, while the elastic bands being fitted into the recess in the closed state.

Description: Technical Field The present invention relates to a snap-type cap structure made of synthetic resin, according to the pre-characterizing portion of claim 1. The "cap structure" used herein is meant to include a cap and a container with a cap. Background Art There is known a cap which is integrally molded of a synthetic resin and having its cap body and cover hinged at three points. This cap is formed by integrally connecting a cap body and a cap opening cover into one piece by means of the three-point hinge. This three-point hinge structure is composed of: 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 those 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 wail 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 the worse, the notches makes it incomplete to shut off the mouth of the cap body with the cover. In order to eliminate the defects of the aforementioned example of the prior art, in which the horizontal plates are attached to the elastic plates and are extended to the central portion of the top wall of the cover, the present invention contemplates to provide a cap structure which can be formed of only the individual rear portions of the circumferential walls of the cap body and the cover without notching the circumferential wall and top wall of the cover, so that the cover may have its appearance improved and may seal up the mouth of the cap body when in the closing operation. EP-A-0 201 457 on which the preamble of claim 1 is based discloses a snap-type cap structure which comprises a film hinge connecting a body and a cover of the cap structure and two tightening bands or straps arranged on both sides of the film hinge. The ends of the tightening bands are attached within recesses provided within the body as well as within the cover. Both tightening bands have a straight shape in the closed state of the cover, from which they are forced to be extended linearly when the cover is turned from the closed state to the dead center state between the closed state and the fully-opened state. For allowing such linear extension without damage to such a tightening band, especially at the ends thereof, careful attention is required with regard to the thickness of the band made from plastic material and the elastic extensity of the band. The bands are stretched in the closed position of the cover to extend substantially parallel with respect to the peripheral wall surfaces of both the cover and the container. GB-A-2 224 309 discloses a cover which is hingedly connected by means of a flexibly resilient elastic band to a base member of a closure a for container. A shape type cap structure according to the present invention is characterized by the features as set out in the characterizing clause of claim 1. Disclosure of the invention In case of an embodiment shown in Fig. 1 to 3, if a cover 5 is pushed up from the open state of Fig. 1, 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 hinges 10 to the cover side end 12b. If the point 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 front in the closed state of Fig. 2. According to the invention, each of the elastic bands 12 is curved in a letter "C" not only in the open state but also in the closed state, in which it is received in a recess 13. The elastic bands can be prevented from being forcibly extended more than their limits even when they pass through the dead center A at which they are extended to their maximum strokes. Fig. 1 to 3 show an embodiment. Fig. 1 is a perspective view showing the open state; Fig. 2 is a perspective view showing the closed state from the back; and Fig. 3 is an enlarged side elevation showing an essential portion. 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 of the like integrally with the aforementioned body 1. This cover 5 can be turned on a later-described hinge 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 and second circumferential walls 2 and 7 having a top plan view of a true circle are connected at their rear upper and lower ends by the hinge 10 and at the righthand and lefthand sides of the hinge 10 by a pair of C-shaped elastic bands 12 and 12. These elastic bands are fitted in the recesses 13, which are formed to extend between the upper and lower portions of the individual backs of the first and second circumferential walls 2 and 7. The recesses 13 have their lower end rear edges and upper end rear edges connected to the lower and upper ends of the elastic bands 12 through second and third hinges 14 and 15. Since, the C-shaped elastic bands are fitted in the recesses 13 formed in the backs of the first and second circumferential walls of the body and the cover when in the closed state, the elastic bands will not deteriorate the appearance of the cap structure. According to Fig. 3, the point of intersection between a straight line c containing the body side end of bands 12 and hinge 10 and an arc b is designated a dead centre A. Bands 12 are extended till dead center A against their elastic force so that the cover is elastically turned over to establish the closed state.

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) being placable on the first circumferential wall, a first hinge (10) for connecting said first and second circumferential wails, a pair of elastic bands (12) which are provided on both sides of the first hinge (10) for connecting said first and second circumferential walls, a pair of recesses (13) for housing a said elastic band, each of said recesses being formed by a lower recess portion on the first circumferential wall and an upper recess portion of the second circumferential wall, each of said elastic bands (12) having a first end connected to an upper end of the recess (13) through a second hinge (15) and a second end connected to a lower end of the recess (13) through a third hinge (14), said second and third hinges (14, 15) being provided at the outer periphery of the recess (13), characterized in that each of said elastic bands (12) has a longitudinal C-shaped configuration maintained in both the closed and fully opened state of the cover (5), said elastic bands (12) being fitted into the corresponding recesses (13) in the closed state. A cap structure in accordance with claim 1, wherein the body (1) is adapted to be secured to an open mouth of a container. A cap structure in accordance with claim 1, wherein the body (1) is a container having the first circumferential wall (2) forming an open mouth.

Inventors: NOZAWA TAKAMITSU, TASAKI TAKAHARU, NOZAWA, TAKAMITSU, TASAKI, TAKAHARU
Applicants: YOSHINO KOGYOSHO CO LTD, YOSHINO KOGYOSHO CO., LTD.
Application year: 1991
Main classification: B65D47
IPC codes: B65D47