Stretch film wrapping device

A stretch film wrapping device for rotatably supporting a roll of plastic film having a tubular rigid central core comprising:

• a base member and a top member mounted at opposite ends of the central core, at least one of said members providing resistance to rotational movement of the film roll as film is pulled from the wrapping device, with the rotational resistance and a consequent increase in film tension and stretching increasing as the pressure between the member and the central core increases;
• an axle interconnecting the two members through a spring connection that urges the members together with a spring force that varies in relation to the amount of distortion of the spring, the spring connection being of a type that permits gradual adjustment of the pressure between the members such that film roll rotation resistance and thus film tension on the roll can be predictably adjusted through a wide tension range short of breaking the film by gradual distortion of the spring connection;
• and
• adjustment means for gradually varying the distortion of the spring connection so as to gradually vary the pressure between the members and the central core, whereby the extent to which the film is stretched while wrapping a package can be maximized and film usage can be minimized.

A stretch film wrapping device for rotatably supporting a roll of plastic film having a tubular rigid central core comprising:

• a base member positioned at one end of the core;
• a top member positioned at the other end of the core, at least one of the members being non-rotatable;
• an axle interconnecting the base member and top member, the axle extending from the base member, through the central core of the film roll, and through the top member;
• a head mounted on the axle on the outer side of the top member, the head being movable with respect to the base member in an axial direction with respect to the axis of the axle;
• disc spring means comprising at least one disc spring positioned between the head and the top member, the disc spring resisting axial compression between the head and top member with a force that increases in generally linear proportion to the amount of compression of the spring, movement of the head inwardly toward the base member compressing the disc spring against the top member with the compressive force of the disc spring and causing the rigid central core to be compressed between the top member and base member with such force, the non-rotatable member providing resistance to rotation of the rigid central core with respect to said member in proportion to the pressure between said member and the rigid central core, whereby the rotation resistance exerted on the plastic film roll and the consequent stretch of the film can be adjusted in a generally linear fashion by axial movement of the head so as to vary the pressure on the disc spring.