| 摘要 |
<p>A packaging machine of the type that is used to hand-wrap a package with a stretchable film that is heat-fused/seaied. The machine includes a supply of film for wrapping a package and a hot plate mechanism for heat fusing the film after the package is wrapped. The hot piate mechanism includes a fever arm that moves a sealing platform from a raised position to a lowered, heat sealing position when the package is piaced on the platform. A control circuit energizes a heating element forming part of the seaiing platform and causes it to reach a desired heating temperature in 2 to 4 seconds, whereby fusing of the sealing film is achieved. An interval timer is used to control a signaling device such as a light to Indicate the machine is in a heating cycle. A separate timer, in conjunction with a temperature sensing thermistor, controls a length of time the heating element is energized and terminates power to the heating element prior to the end of a sealing Interval if a predetermined temperature is exceeded. The sealing intervals are selectable by the operator using a muiti- pos?tioned switch which connects selected timing resistors to the interval timers. Power to the heating element is only delivered to the heating element during a heating cycle, thus conserving electrical power,</p> |
