Hitherto, there have been proposed and utilized many types of binding devices for filing papers and the like, which as a binding volume increases generally become unstable for binding operation, resulting in removal of bound papers. To file a great volume of papers or the like, therefore, special contrivances have been required for such binding devices.
A binding device of the aforementioned type has been disclosed in the Japapese Laid-open Patent Publication No. 48-58915. Namely, according to one embodiment of this conventional binder particularly as shown in FIG. 11, the binding device comprise a fixture 10 and a cover plate 12 both made of synthetic resins, said cover plate 12 being provided with a slide opening 14 for slidably supporting a slide piece member 18 with engagement recesses 16, 16 so that the slide piece member 18 upon movement engages and disengages with a recess of a binding rod 20 for fixing and releasing the cover plate 12 from the fixture 10.
Furthermore, according to another example as shown in FIG. 12, a slide plate 22 is integrally formed with a cover plate 24 and at the boundary portion between the slide plate 22 and the cover plate 24 is formed a hinge slit 26 for conveniently releasing the cover plate 24. The slide plate 22 is further provided with a slide slit 28 providing therein a fixing plate 30 which includes binding rods 34, 34 having engagement recesses 32, 32, while the cover plate 24 is provided at its external end with engagement piece members 36, 36 for engagement with the recess 32 of the binding rod 34 and the slide plate 22 and the cover plate 24 are moved together toward the fixing plate 30 to engage the binding rods 34, 34 with the cover plate 24. The fixture is further connected with the cover plate by means of a spring and under the spring function the cover plate may be enagaged with or removed from the binding rods.
In other words, according to such a conventional binding device the binding rods 20, 20 or 34, 34 for binding papers are firmly supported and engaged within a solid frame body comprising a fixture 10, a cover plate 12 and a slide piece 18 or a slide plate 22, a fixing plate 30, a cover plate 24 and engagement pieces 36, so that the filed papers, even if in plenty, may neither be unstable nor released.
The binding devices as hereinbefore described, however, usually consist of a plural member of components in combination, resulting in their complicated manufacturing process with a high cost and are further troublesome in filing operations.
Therefore, an object of the invention is to provide a binding device which may be integrally molded and may provide a convenient binding operation.