| 摘要 |
<p>A reclosable opening device (2, 2') having a tubular frame (10) having at least one first thread (20) and fitted about a pierceable portion (4) of a package (1) for pourable food products; a removable cap (12) having a second thread (22) which engages the first thread (20) to screw the cap (12) onto the frame (10); tamperproof means (28) connected to the cap (12) by breakable connecting means (29); and cutting means (13, 31) controlled by the cap (12), and which, following breakage of the breakable connecting means (29), shear the pierceable portion (4) to unseal the package (1); one (20) of the threads (20, 22) has, at a portion engaged by the other (22) of the threads (20, 22) at the transient stage between detachment of the tamperproof means (28) and initial shearing of the pierceable portion (4) by the cutting means (13, 31), successive thread portions (40, 41) separated by a small distance (Dl), so as to eliminate the clearance between the threads (20, 22) at the aforementioned portion.</p> |
