Anvil Construction for Ultrasonic Sealing Device

摘要

1,158,578. Seaming non-metallic sheet material. UPJOHN CO. 12 Oct., 1966 [12 Nov., 1965], No. 45580/66. Heading B5K [Also in Division B8] An anvil 46 for an ultrasonic sealing machine is made of a non-metallic, non-thermoplastic material having (a) a modulus of elasticity of at least 1À0 x 106 p.s.i., (b) a Brinell hardness of at least 15 (500 kg. load, 10 mm. diameter ball) or a Sceloscope hardness of at least 40, (c) a compressive strength of at least 500 p.s.i., (d) a thermal conductivity of less than 6 B.T.U./hr./sq. ft./‹ F./inch, and (e) a flexural strength of at least 4000 p.s.i. The material may have the following additional properties (a) a specific gravity of at least 75 1b./ft.3, (b) a tensile strength of at least 1500 p.s.i., and (c) a Charpy Impact reading of at least 2À0 foot-pounds. An ultrasonic sealing and cutting machine 20 comprises a transducer 23, preferably of the magnetostrictive type, connected to a generator (not shown) and which ultrasonically vibrates a tool 24 formed with a tungsten carbide disc 25 to contact the sheets to be sealed. A carriage 31 for the anvil 46 is slidably mounted on rods 26, (27), the latter not shown, and is formed with an undercarriage 32 connected, through a resilient coupling 33, a rod 34 and a crank 36, to a lever 35 manually operable to allow the insertion of the sheet edges to be sealed between the tool 24 and the anvil 46. The movement of the carriage 31 towards the tool 24 is limited by a post 43 on the carriage 31 engaging an adjustable shaft 42 on a micrometer head 41. The anvil 46 is of generally circular section, is formed with outwardly projecting flanges 48, 49 and is secured to the carriage 31 by a screw 47. The tool 24 co-operates with the flange 48 and when one portion of the periphery of this flange is worn the anvil is rotated, after loosening of the screw 47. When the entire flange 48 is worn, the screw 47 is removed and the anvil 46 is inverted so that the flange 49 co-operates with the tool 24. The anvil 46 may be made of Portland cement having asbestos fibres therein in the form of staple fibres or a woven fabric. Alternatively, the anvil 46 may be a layered carbon cloth material bonded together with carbon. The machine may be used to seal the overlapping ends of a polyvinyl chloride shrink film wrapper which has been wrapped about a bottle containing a pharmaceutical product and to simultaneously cut off any excess film material.