A method for applying a threaded closure to a container, said closure having sealing means in or towards the crown thereof, which method comprises applying the closure to the container by the application of a predetermined rotary torque thereto, continuing the application of the closure to the container until the desired torque applied is obtained and thereafter applying axial pressure to the closure crown towards and on to the container while simultaneously applying said torque whereby the closure pressure serves to disengage the threads to overcome at least some of the friction therebetween to permit a greater proportion of the applied torque to be applied to the sealing means within the closure.
A closure applying apparatus (1) suitable for use in capping machines for placing, on a container (B) having a threaded neck portion (26) and an annular collar (30) below said neck portion, a tamper-evident screw-type capsule (A) made of rigid plastic material and having a lower skirt portion (27) which is connected by a plurality of thin frangible bridge portions (28) to an upper internally threaded skirt portion (22) and is provided with an inwardly projecting bead (29) for snap engaging beneath said annular collar (30) as a result of screwing of the capsule (a) on the container (B). The apparatus comprises a rotary, vertically reciprocable capping chuck having a plurality of jaws (4) for gripping the capsule (A), each jaw (4) being provided at its lower end with an inner flange (14) which engages from below the edge of the lower skirt portion (27). The flange (14) of the jaws (4) form an abutment surface for the lower skirt portion (27), which absorbs the forces produced during snap movement of the inwardly projecting head (29) over the collar (30) of the container (B), thus preventing fracture of the bridges (28) during the capping operation.
A capping assembly includes at least one tube fixed to a spindle of an automatic machine and provided with a piston and cylinder unit for axially displacing a bush operatively connected with the tube and formed with a shaped recess to releasably engage a respective formation on a cup support upon displacement of the piston in the cylinder.
A capping apparatus 1 includes torque sensor 12 which detects an output torque when a chuck 7 is driven for rotation by a motor 9. Initially, a cap 5 is held by the chuck 7. The cap 5 is fitted over a mouth of a vessel 2, and then the chuck 7 is rotated through one revolution in a clamping direction. A resulting output torque is detected by the torque sensor 12, and the output torque rapidly increases at the position where the threads on the cap 5 and the vessel 2 abut against each other (an incipient position of meshing engagement P). The cap 5 is rotated through a given angle of rotation as referenced to the incipient position of meshing engagement P, thus threadably engaging the cap 5 with the vessel 2. The invention allows a uniform clamping of cap 5 at the completion of the capping operation.
A capping apparatus 1 includes torque sensor 12 which detects an output torque when a chuck 7 is driven for rotation by a motor 9. Initially, a cap 5 is held by the chuck 7. The cap 5 is fitted over a mouth of a vessel 2, and then the chuck 7 is rotated through one revolution in a clamping direction. A resulting output torque is detected by the torque sensor 12, and the output torque rapidly increases at the position where the threads on the cap 5 and the vessel 2 abut against each other (an incipient position of meshing engagement P). The cap 5 is rotated through a given angle of rotation as referenced to the incipient position of meshing engagement P, thus threadably engaging the cap 5 with the vessel 2. The invention allows a uniform clamping of cap 5 at the completion of the capping operation.
