This invention relates to a dispenser for sheet material, particularly to a dispenser that dispenses individual sheets of a material, such as paper towels, from the center of a coreless roll divided into a plurality of sheets by partially severed spaced apart lines.
A number of dispensers exist in the prior art for dispensing paper towels and similar sheet materials. One method of dispensing involves a xe2x80x9ccenter-pullxe2x80x9d mechanism whereby the sheet material is removed from the center of a coreless roll. The sheet material is pulled through a restricted opening that frictionally resists the pulling motion from the user. This resistance results in the sheet material tearing away into individual sheets at predetermined points marked by partially severed lines.
The most common design of center-pull dispenser uses a cone or funnel shaped nozzle to provide the opening for resisting and dispensing the sheet material. This design provides a large initial entrance for the end of the sheet material roll that allows for easy insertion of the end of a new roll, while also having the restricted exit opening necessary to provide sufficient resistance to allow tearing of the perforations.
There are a couple of problems with the current center-pull dispenser designs. First, some dispensers have the point of the opening formed by the casing which is of a relatively inexpensive plastic. The repeated passage of the sheet material against the exit opening wears down this plastic, eventually making the opening too large to provide proper resistance for tearing the perforations. In most cases, the entire unit must be replaced to resolve this problem.
A second problem is the need for multiple dispensers for different types of sheet materials. Different grades of sheet material require exit openings of different sizes and shapes. Ideally, a sheet material dispenser should be adjustable to allow dispensing of different grades of sheet material.
U.S. Pat. No. 5,749,492 discloses a center pull type of sheet dispenser which uses a funnel shaped plate having a central opening and a gap to allow passing the tail of a roll of paper towels through an exit aperture at the bottom. In one embodiment the cover or door closes to form the exit aperture through which the tail of the roll of paper hangs. However there is a significant risk of the sides of the funnel that abut one another closing on the paper. In yet another embodiment, two box end elements overlap below the exit aperture to define the exit aperture. With the particular design of one box end element over another, it is difficult to set the exit aperture so that it tears the roll and leaves an appropriate tail. This is due to the fact that the tail passes alternately, a semicircular jaw on one side then one on another side. With this type of structure, either tearing occurs prematurely of not at all.
Therefore, it is an object of this invention to provide a sheet material dispenser that has a modified exit opening that eliminates wear caused by friction from the sheet material.
It is a further object of this invention to provide a sheet material dispenser with an exit opening that can be adjusted in shape or size to allow the dispensing of different grades of sheet material.
The invention consists of a paper towel dispenser for dispensing individual sheets of paper towels from a roll of paper having regularly spaced apart lines of partial severance. The dispenser is comprised of a hollow housing for receiving the roll of sheet material and a housing door, which can be pivotally opened to allow a roll of sheet material to be inserted into the dispenser. Advantageously, a bottom of the hollow housing and the housing door each have opposed concave surfaces which together define an exit aperture when the door is closed against the housing.
A funnel-shaped region at the bottom of the hollow housing terminates at the funnel outlet and has an opening along one side to permit entry of an end region of the roll. A paper towel ring assembly is positioned adjacent to the funnel outlet and includes a wear-resistant ring that is made of two halves, one half is positioned in the concave surface of the housing door and another half in the concave surface of the hollow housing such that on closing the housing door against the hollow housing, the two halves abut to form a wear-resistant ring. The wear-resistant ring is positioned in the exit aperture and encircles the tail of said roll. A paper towel tearing member is moveable over the wear-resistant ring and is adjustable to vary the size of the exit aperture so as to adjust the position at which each sheet tears away from the roll. This allows the use of different types of sheets of material in a single dispenser.
Preferably the exit aperture is positioned between an axis of the hollow housing and the housing door so as to provide sufficient room for a user""s hand between an end of the roll and a wall to which the dispenser is mounted.
The paper towel tearing member may have a concave contour.
A raised block having a convex contour may be mounted opposed to the concave surface of the paper towel tearing member and mate with the paper towel tearing member when the paper towel tearing member is adjusted to contact the raised block.
When the user pulls on the roll end, the material rubs along the paper towel tearing member and the friction creates enough resistance to allow separation of individual sheets of material along pre-determined perforations to begin. Further pulling causes a predetermined tail from the subsequent sheet to hang out at the bottom of the dispenser. The wear-resistant ring is extremely resistant to the wear caused by the repeated use of the dispenser.
The adjustment of the paper towel tearing member may be provided by a sliding plate composed of the same wear-resistant material as the ring.
Preferably, the wear-resistant ring is also removable, to allow replacement of the wear-resistant ring in order to adjust the shape of the exit aperture to accommodate different grades of sheet material.