It is conventional to dispense paper towels from an upright roll, that is, a roll whose center axis is oriented vertically. The center of the roll is coreless, so the paper can be pulled from the inner periphery of the roll, that is, usually downwardly through a hole formed in a floor of a dispenser housing. Therefore, the radial thickness of the roll gradually diminishes from a roll inner periphery toward a roll outer periphery. Eventually, only a very small radial thickness of the roll remains.
It is also conventional to dispense paper towels from a vertical stack of individual towels or from a horizontal roll that rotates about a horizontal axis.
It is desirable for the user to be informed when the paper reserve is low in dispensers of the above-described types.
Low-reserve indicators have been previously proposed for paper towel dispensers of the type wherein individual towels are arranged in a vertical stack (see U.S. Pat. No. 1,738,721), or in a horizontal roll (see U.S. Pat. Nos. 2,601,956 and 3,273,773). In U.S. Pat. No. 1,738,721, the low reserve indicator includes a follower roller which rests upon the top of the stack and travels downwardly as the stack is depleted. The roller is attached by a lever arm to a pointer which is visible through a window disposed in a upper portion of the dispenser housing. The pointer rotates as the roller descends, in order to traverse a space between an “empty” indicia and a “full” indicia. Shortcomings of such an indicator include the fact that the roller must be manually held in a raised state by an operator who is loading fresh towels in the dispenser, thus complicating the re-filling operation. Also, the lever must be relatively long in order to extend between the pointer and the roller when the roller is at its lowermost state, whereby the expense, weight, size etc. of the indicator are greater than would be desired.
In each of U.S. Pat. Nos. 2,601,956 and 3,273,773, a relatively long indicator arm must be provided in order to extend to an outer cylindrical periphery of a paper roll U.S. Pat. No. 2,601,956, or in order to extend along and past the entire longitudinal length of the paper roll U.S. Pat. No. 3,273,773. Such long elements increase the overall cost of providing a low reserve indicator mechanism.
Also, it will be appreciated that the low reserve indicators described above are not suitable to a vertically oriented roll, let alone a coreless roll whose towels are pulled from the inner periphery of the roll.