Patent Application
20120104144
The invention relates to a retention mechanism in a dispenser for retaining an end plug of an exchangeable roll of material. Further, the invention relates to a system of a retention mechanism and an end plug of an exchangeable roll of material in a dispenser.
Numerous dispensers for dispensing hand towels, paper towels, toilet paper, foil, plastics wrapping sheet and other materials wound onto a roll are known in the art. Usually, such dispensers are provided with a supporting frame having support members in the form of arms upon each of which an end of an exchangeable roll is rotatably mounted. In one solution a support arm carries a hub member supported thereon over which one end of the roll core is inserted when replacing the roll. To the other end of the roll, an end plug is secured which is inserted in a catcher mechanism in the other support arm of the dispenser. By means of providing an end plug only on one side of the roll, the correct placement of the supply roll relative to the dispensing mechanism and, consequently, the proper feeding of the sheet material is ensured.
Different suggestions have been made in order to ensure the proper feeding of dispensers or to prevent the insertion of unauthorized paper rolls of inferior quality into the dispenser. EP 0 657 134 B1 provides a solution to the problem to prevent the wrong insertion of paper rolls into a dispenser. The paper rolls are provided with plugs on both sides, the plug on the one side having a larger diameter and a slit which divides the pin into two crescent-shaped segments. This geometry is adapted to match a specific receiving geometry of the dispenser which is provided with corresponding depressions for receiving the crescent-shaped segments of the bearing pin being part of the plug.
Based on the object to prevent unauthorized paper rolls, U.S. Pat. No. 2,905,405 describes a coupling mechanism having openings of a special shape within a flange plate of the dispenser. The end plugs of the exchangeable replacement rolls have matching projections to be inserted through these openings. The projections of the end plugs inserted through the openings press on leaf springs biasing them into a position in which they do not impede the proper operation of the dispenser. Only replacement paper rolls having all matching projections can be used in order to operate each individual leaf spring.
Another similar technical solution is known from U.S. Pat. No. 6,749,149 B1. The dispenser described therein has support arms for supporting a paper towel roll having a selected geometry with protrusions shaped to fit into matching openings in the end faces of the paper towel roll.
WO 2005/094653 A1 describes a lock mechanism for a dispenser in combination with an exchangeable roll of material which provides a key-lock-system which is easy to operate if an exchangeable roll of material is provided with at least one end plug of the right geometry. The key of the system is the geometry of the bearing pin of the end plug, whereas the lock of the system is part of the dispenser. The dispenser is provided with a lock housing with a guide slot for insertion of the bearing pin. The guide slot is subdivided into sections of different width wherein the different sections are arranged such that they extend in a longitudinal direction of the bearing pin of the end plug to be received. This key-lock-system prevents the introduction of a plug with wrong dimensions, and additionally provides a safety means ensuring the proper longitudinal position of the replacement roll when inserting into the dispenser.
The above-described solutions serve the purpose to ensure the proper insertion of a roll of material provided with the matching geometry to some receiving structure. However, such paper rolls having a specific geometry with projections to be inserted in corresponding depressions in the receiving geometry are difficult to handle. The user cannot simply insert a replacement roll but has to check its proper orientation relative to the receiving structure. Further, there is the danger of wrong operation or that the user applies undue pressure to push a replacement roll into the dispenser.
It is an object of the present invention to provide a retention mechanism for a dispenser and a system of a retention mechanism and an end plug of an exchangeable roll of material such that the insertion of a replacement roll is very easy but still the inadvertent use of a wrong or unauthorized roll is effectively prevented.
This object is solved by a retention mechanism for a dispenser as broadly described herein. The system of a retention mechanism and an end plug of an exchangeable roll of material is also a part of the present invention.
The inventive retention mechanism for a dispenser for retaining an end plug of an exchangeable roll of material comprises a housing with an insertion slot extending between a receiving end and a seating region for inserting a bearing pin of the end plug. The bearing pin is provided with at least two sections, a first portion with a first diameter, and a second portion with a second diameter, the second diameter being smaller than the first diameter. The retention mechanism further comprises a pin discriminator means which is provided at least at the receiving end of the insertion slot and narrows the receiving end of the insertion slot such that only bearing pins can enter the receiving slot which have a maximum outer diameter at the second portion which equals to the second diameter. Further, the retention mechanism comprises a rejecting slot extending from the seating region, the rejecting slot being dimensioned such that only bearing pins with a predetermined maximum diameter in the first portion which is smaller than the first diameter can enter the rejecting slot.
The retention mechanism has a very simple structure and in case of the provision of the pin discriminator means as a stationary rib, there are no moving parts involved. Once an end plug of an exchangeable roll of material has been correctly received in the seating region, it can freely rotate therein. Any plug provided with a bearing pin not having the right dimensions in the first portion and second portion are rejected. In case of a wrong operation, i.e. the use of a wrong exchangeable roll with a wrong bearing pin, the user cannot readily damage the retention mechanism. The pin discriminator means is provided at the receiving end of the insertion slot and already narrows the receiving end such that bearing pins which have an outer diameter in the second portion exceeding the required one cannot even enter the insertion slot.
Wrong end plugs having generally dimensions of the bearing pins which are too small, can also not damage the retention mechanism. Such end plugs can enter the insertion slot because they are not rejected by the pin discriminator means. However, once such a plug entered the insertion slot, a user can no longer apply pressure. Such end plug travels through the insertion slot up to the seating region where it cannot be properly held. As a result of this, such a wrong end plug enters and moves through the rejecting slot where it is finally held or leaves again the retention mechanism.
Reference to a maximum outer diameter in a second portion which equals to the second diameter as well as reference to a predetermined maximum diameter in the first portion which is smaller than the first diameter indicates that care should be taken to account for possible tolerances when manufacturing the retention mechanism as well as the bearing pin of the end plug. Therefore, it is advisable to design the pin discriminator means as well as the dimensions of the rejecting slot such that also end plugs having certain, small variations in the diameter of the first portion and of the second portion can still be used. With regard to the rejecting slot, a smaller dimension of the rejecting slot has the additional advantage that the seating area within the seating region becomes larger which gives an improved support to the bearing pin of the end plug.
According to a preferred embodiment of the invention, the retention mechanism further comprises a loading ramp extending in insertion direction to the receiving end of the insertion slot and being dimensioned to support the bearing pin before entering the receiving end of the insertion slot. Such a loading ramp can be designed to have a slope going up in the insertion direction. In such a case, a wrong plug rejected by the pin discriminator means slides back down the loading ramp to be easily removed again by the user.
A further function of the loading ramp is a positioning of the bearing pin relative to the discriminating rib. By sliding up the loading ramp, the vertical position of the bearing pin relative to the pin discriminator means is defined.
Preferably, the loading ramp is provided with a positioning surface which is perpendicular to a support surface of the loading ramp and essentially parallel to the insertion direction. By providing such additional positioning surface which, in the mounted state within a dispenser, is essentially vertical, a pre-positioning of the bearing pin in an axial direction can be achieved. Such pre-positioning has the advantage that the bearing pin of the plug is correctly positioned relative to the pin discriminator means.
Preferably, such positioning surface comprises a rib extending from the support surface of the loading ramp and being arranged to abut during the insertion of an exchangeable roll of material against a step portion between the first portion and the second portion of the bearing pin. In order to achieve this, a curved rib could be used which, independently of an inaccurate loading of the roll of material onto the loading ramp, extends into the second portion of the bearing pin and moves towards the position where the step portion between the first portion and the second portion of the bearing pin should be. In such a way, an inaccurately inserted exchangeable roll of material is axially shifted and positioned during the sliding movement on the loading ramp up to the insertion slot.
According to a preferred embodiment of the invention, the insertion slot has a curved longitudinal extension and preferably is essentially vertically oriented. Such curved extension and preferably also vertical orientation prevents the undesired climbing up of the pin when the roll of material rotates. When material is dispensed, the roll rotates and the bearing pin could roll up the insertion slot if it were e.g. provided essentially horizontally.
According to a preferred embodiment of the invention, the rejecting slot extends essentially vertically and with an open end remote from the seating region. Any wrong end plug drops vertically into and through the rejecting slot. The provision of an open end has the advantage that the wrong exchangeable roll of material will leave the retention mechanism again so that it can be conveniently removed by a user without requiring lifting up of the roll of material so that the bearing pin moves up through the possibly curved insertion slot and out of the receiving end of the insertion slot.
In order to achieve this, it is preferred that the retention mechanism is positioned within a retention arm of the housing. Therefore, an open end of the rejecting slot will leave the retention arm again and does not block or even damage the retention mechanism positioned within the retention arm.
Preferably, the bearing pin further comprises a third portion with a third diameter being larger than the second diameter, the second portion being situated between the first portion and the third portion and forming a circumferential groove between the first portion and the third portion. In such a case, it is preferred that the pin discriminator means is a rib with a width which corresponds to the width of the groove. In other words, the provision of a third portion generates a further discriminating criterion. Now it is not only the rough position and diameter of the second portion which is used to allow the entrance of a bearing pin in the insertion slot, but also the width of the circumferential groove formed between the first portion and the third portion of the bearing pin. If the width of the groove and the depth of the groove are both of the required dimensions, the entrance to the insertion slot is possible.
Instead of the pin discriminator means being a single ridge, it is alternatively also possible to form the pin discriminator means by two parallel ridges. Such parallel ridges can be arranged such that their outer side surfaces are at a distance corresponding to the width of the groove. A further alternative is the provision of the pin discriminator means as a spinning wheel. A spinning wheel reduces the friction between the bearing pin and the pin discriminator means.
When a bearing pin forming a groove between a first portion and a third portion is used, the bottom of the groove preferably has a complex cross-sectional shape which is complementary to the shape of the bottom of the groove. This provides a key-lock function which could be used for a further discrimination of a specific type of exchangeable roll of material within a dispenser. If a certain type of dispenser can be used for dispensing different types of material, such specific discriminator means could be used to identify the specific type of material and, accordingly, to adjust further parameters like the dispensing length for each single dispensing operation.
The insertion slot has preferably a first guide surface and a second guide surface opposite to the first guide surface. At least in the seating region, the first guide surface has a geometry complementary to the shape of the bearing pin. This means that, in the seating region, a high surface contact area between the seating region and the bearing pin can be realized. A further advantage resides in the fact that an inadvertent axial movement of the roll of material can be effectively prevented because the correct axial positioning is maintained by the shape of the guide surface complementary to the shape of the bearing pin. This positioning function is achieved already when at least the first guide surface has such a geometry. However, it is preferred that, at least in the seating region, both guide surfaces have a geometry complementary to the shape of the bearing pin. This has the specific advantage that the loading on the tip of the bearing pin becomes more symmetrical.
The inventive system of a retention mechanism and an end plug of an exchangeable roll of material in a dispenser has at least one retention mechanism mountable in the housing of the dispenser, wherein the at least one retention mechanism is designed to hold an end plug in a seating region. Further, each end plug comprises a fitting portion dimension to fit into a hollow core of the roll of material, and a bearing pin extending from the fitting portion. The bearing pin is provided with at least three sections. A first portion with a first diameter, and a second portion with a second diameter, the second diameter being smaller than the first diameter, and a third portion with a third diameter being larger than the second diameter, the second portion being situated between the first portion and the third portion in forming a circumferential groove between the first portion and the third portion. The retention mechanism further comprises an insertion slot extending between a receiving end and the seating region and a rejecting slot extending from the seating region. The retention mechanism further comprises a pin discriminator rib provided at the receiving end of the insertion slot. The retention mechanisms and the end plug are shaped such that a pin discriminator rib prevents end plugs to enter the insertion slot which have a diameter in a second region which is larger than a predetermined diameter, whereas the rejecting slot is dimensioned such to receive end plugs with a bearing pin, the diameter of the first portion and/or third portion of which is smaller than a second and/or third predetermined diameter. The retention system as such only works properly if both the retention mechanism and the end plug are dimensioned such as to allow the bearing pin to enter the insertion slot and to be held in the seating region of the insertion slot. Any end plug which does not meet the above-described requirements with regard to the predetermined diameter in the second portion and a second and/or third predetermined diameter in the first and/or third portion do not fulfill the requirements for a successful loading of the dispenser so that such end plug is either rejected by the pin discriminator rib or through the rejecting slot within the retention mechanism.
The retention mechanism and the pin side arm of the dispenser can be a unitary structure. However, it is preferred that the retention mechanism is a separate part mounted to the pin side arm of the dispenser. This makes it possible to easily replace the retention mechanism if damaged or worn or to update the dispenser to a new generation of retention mechanism.
The inventive retention mechanism and system is of a very simple structure because there are no moving parts required. Nevertheless, the retention mechanism is able to provide a highly accurate positioning of the end plug of an exchangeable roll of material. Wrong materials are easily rejected without the possibility that a user can apply force which could lead a damage of the retention mechanism and dispenser. Due to the simple structure, the retention mechanism can be manufactured easily and with low costs.
In the following, exemplary embodiments of the invention will be described in detail with reference to the drawings, in which
In the following description of preferred embodiments of the invention, corresponding parts or elements in the different drawings will be denoted by the same reference numerals.
The end plug 10 further comprises a bearing member 20 with a bearing pin 22 which, in the specific embodiment as shown in
The bearing pin 22 is formed by a first portion 26 with a first outer diameter d1 that merges into a second portion 28 of the bearing pin that has an outer diameter d2, whereas the first diameter d1 is larger than the second diameter d2. The counter surface 24 is situated between the first portion 26 and the second portion 28 of the bearing pin 22. The counter surface 24 may have different forms and be inclined with respect to the longitudinal axis of the bearing pin, perpendicular to the longitudinal axis of the bearing pin 22 or chamfered.
Furthermore, the bearing pin 22 includes a third portion 30 of a third outer diameter d3 whereas the third outer diameter d3 is shown in the embodiment to be equal to the first diameter d1. However, it is not necessary that the first diameter and the third diameter are equal, or that the third portion 30 be provided at all. Moreover, the first portion 26 may be on either side of the second portion 28.
Therefore, reference to a first and a second portion may also apply to the third and second portion as described in this embodiment.
The bearing member 20 also includes an inclined surface 32 connecting the bearing pin 22 to the fitting portion 12. Such inclined surface 32 can be used for locking the end plug in an end position in the retention mechanism as is described in EP 1 795 479 A1 incorporated herein by reference. In this case, the inclined surface is inclined with respect to a longitudinal axis of the bearing pin by an angle in the range of 117° to 141°, preferably 120° to 122°, and most preferably of 121.1°.
In the end plug as shown in
In a preferred embodiment the end plug is of one-piece construction and is formed of injection molded plastic material, although it is within the scope of the invention to form the end plug from plural parts and to use other materials.
The pin side arm 34 can be fitted in any suitable way to the housing of the dispenser. Although
The retention mechanism is a three-dimensional structure with the main components of an insertion slot 42, a loading ramp 44, a pin discriminator means 46, a rejecting slot 48 and a seating region 50.
The loading ramp 44 is a sloped surface which, in the embodiment as shown in
The insertion slot 42 has a receiving end 54 at the upper end of the insertion slot. References to “upper end” or “lower end” or “vertical” refer to a retention mechanism correctly inserted in the pin side arm of a dispenser in its operating position, e.g. mounted to a wall. In such an operating position, the insertion slot 42 is essentially vertical between the receiving end 54 and the seating region 50. However, it is advantageous that the receiving slot is curved providing a curved path for the bearing pin of an end plug passing through the insertion slot. The general vertical arrangement and the curved path both serve the purpose to prevent the bearing pin to move back from the seating region 50 to the receiving end 52 when the paper roll correctly installed in the dispenser is rotated. In other words, the bearing pin of a plug should be prevented from riding up the insertion slot.
Starting from the seating region 50, there is a vertical rejecting slot 48 which, in the embodiment as shown in
The insertion slot 42 is formed between a first guide surface 58 and a second guide surface 60 (see
Close to the receiving end 52 of the insertion slot 42, a pin discriminator means 46 is provided which, in the embodiment as shown in
The dimensions of the pin discriminator means 46 have to be suitably adapted so that, in cooperation with the loading ramp 42 and the receiving end 54 of the insertion slot 42, the correct geometrical discrimination can be made.
The above-mentioned pre-positioning rib 52 on the loading ramp 44 as shown in
In the embodiments as shown in
In a preferred embodiment the retention mechanism is of one-piece construction and is formed of injection molded plastic material, although it is within the scope of the invention to form the retention mechanism from plural parts and to use other materials.
Next, the operation of the system of a retention mechanism and an end plug will be explained with reference to
In this seating region 50, the bearing pin is held and supported by a structure which is shaped complimentary to the shape of the bearing pin 22. In this context, the first seating rib 62 and the second seating rib 64 were described with reference to e.g.
However, it is also possible to provide only the first seating rib 62 or the second seating rib 64. This is schematically shown in
The operation of the retention mechanism 38 will be explained by way of two examples with reference to
In the appended claims, specific embodiments of the invention are described. Wherever this is technically feasible, each and every combination of such features should also be covered by the invention.
