| 摘要 |
A machine with a packaging station, at which trays having products are sealed. Opposed parallel sets of belts move in synchronism with each other transversely to the direction of movement of the trays along the packaging station. Each set of belts has an upper belt and a lower belt adjacent to each other and moving in the same direction at the same speed. One end of the adjacent runs receives a sheet of film. A plurality of jaws are located on each of the opposed sets of belts, each set of jaws receiving adjacent runs and an edge of the film. The opposed sets of belts are moveable relatively towards and away from each other, such that the jaws can hold films of different widths and such that the film held therebetween can be stretched and relaxed. A clamp is connected to each set of jaws. The clamp is spring biased to the separate the top and bottom thereof. A power element exerts a selective force onto the bottom of the clamp to close the adjacent runs onto the film. Cams have profiles which, acting through levers, applies a closing force onto the jaws. |
| 主权项 |
1. A machine having a packaging station at which trays having products therein are sealed with a heat-weldable stretch film, comprising;
opposed parallel sets of belts, which belts are mounted to move in synchronism with each other transverse to the direction of movement of the trays along the packaging station, each set of belts having an upper belt which has a lower run and which runs adjacent an upper run of a lower belt, said adjacent runs constructed to move in the same direction as each other at the same linear speed, an end of the adjacent runs of each set of opposed belts constructed to receive a sheet of film which is fed along the adjacent runs into the packaging station, a plurality of jaws arranged on the side of each opposed set of parallel belts, which side faces towards the other of the opposed sets of belts, each set of jaws positioned to receive both of said adjacent runs, with an edge of the film between them, the opposed sets of belts being movable relatively towards and away from each other while remaining parallel to each other, such that the jaws can hold films of different widths and such that when the film is held by the jaws on both sides, relative movement of the opposed sets of belts away from and towards each other will stretch and relax the film, respectively, and a clamp connected to each of said jaws, the clamp being spring biased to separate the jaws from each other, and including a power element arranged to exert a selective force to close the jaws onto the film and the adjacent runs, a cam operatively engaging each power element, each cam having an outer profile with varying heights, and movable to place different heights of the profile into operative engagement with its respective power elements such that its closing force is viable, depending on the height of the cam profile operatively engaging its respective power element at any given time. |
