| 摘要 |
1528266 Web dispenser M GRANGER 16 Nov 1976 [19 Nov 1975 11 Feb 1976] 47778/76 Heading B8M A device for dispensing web material comprises a rotatable roll R of web material mounted in a support A and biased by springs 11 to engage a drum 17 also mounted rotatably in the support A so that the drum 17 rotates when the web material is pulled, the drum 17 being mounted on a shaft 18 which is non-rotatably secured to a lever 26 which is connected to one end of a spring 21 the other end of which is secured to a structure C mounting the drum 17 inside the support A, a cutter 25 located inside the drum 17 and operated by a camming arrangement, the arrangement being such that when the web is pulled the drum 17 rotates thereby stressing the spring 21 which stores energy until a point is reached when the spring 21 releases its stored energy to vigorously rotate the drum 17 in the same direction, and simultaneously the camming arrangement causes the blade 25 to project through a longitudinal slot 17b in the drum 17 to cut the web material instantaneously and after the cutting operation to retract into the drum 17. When the spring 21 releases its energy and rotates the lever 26 to rotate the drum 17 a cam 19a co-operates with a roller 22 of the cutter assembly to displace the cutter 25 exteriorly of the drum 17. During this drum movement a pawl 28 mounted on the drum shaft 18 brushes past an abutment 30 provided on a flange 5b of the carrier C. After the cut, the drum 17 rotates due to its own inertia until the pawl 28 engages a shock absorber 29, mounted on the shaft 18, which brakes the drum. A spring 31 which is compressed to provide the brakes then relaxes to rotate the shock absorber 29 and to rock the pawl 28 in the reverse direction only to engage it with the abutment 30. The support A is made of sheet material and its hood 4 is made of sheet metal or plastics. The cutter 25 is either embedded in its carrier 24 or moulded integrally. In another embodiment (Figs. 11-17) the cam arrangement is constituted by a roller 51 provided on an arm of the blade 49. The blade 49 is pivotally mounted at a point 49f to an end plate 46c of the drum. The roller 51 rides in a cam groove 5e provided in a flange 5b of the carrier C. When the roller 51 assumes the peak portion (c-d) of the cam groove 5e the blade is projected to cut the web and when it enters portion d-a the blade is retracted. The blade begins its exit after one quarter of the revolution of the drum from its rest position and remains projected for one fifth of the drum revolution. In another embodiment two drum units are mounted together to be used alternately or simultaneously, Figs. 18-20 (not shown). |
