| 摘要 |
A packaging machine of the type that is used to hand-wrap a package with a stretchable film that is heat-fused/sealed. 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 plate mechanism includes a lever arm that moves a sealing platform from a raised position to a lowered, heat sealing position when the package is placed on the platform. A control circuit energizes a heating element forming part of the sealing 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 multi-positioned 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. In an alternate embodiment, the package to be sealed is sensed by a photo eye assembly as the package is positioned on the hot plate assembly. The frame of the alternate embodiment includes a lower base member to which an upper base plate is rigidly attached. The upper base plate is preferably formed from a continuous sheet of material such as steel and includes a support surface for the hot plate, a vertical wall to which the photo eye assembly is attached that is interconnected with the support surface by a curved transition surface. The upper base plate also includes a lateral, rearwardly extending plate portion which defines at least a portion of a hardware enclosure. |
