WO2007068270A1

WO2007068270A1 - Quantity sensing device in an automated dispenser, a dispenser containing same, a method of determining quantity and a supply roll for use in said dispenser and method

Info

Publication number: WO2007068270A1
Application number: PCT/EP2005/013449
Authority: WO
Inventors: Kin Lun Mok; King Lun Mok; Hong Ng
Original assignee: Sca Hygiene Products Ab
Priority date: 2005-12-14
Filing date: 2005-12-14
Publication date: 2007-06-21

Abstract

A quantity detection means for sheet material (17) stored as a supply roll (7) includes a control means (31) which is arranged to compare the amount of rotation of a drive roller (9) to the amount of rotation of the supply roll (7) during the same time period. A dispenser (1), e.g. for paper towelling, including such a quantity detection device may provide a warning when the amount of sheet material (17) has reached a predetermined threshold. A method for determining the quantity of sheet material (17) remaining is also included.

Description

Title: Quantity sensing device in an automated dispenser, a dispenser containing same, a method of determining quantity and a supply roll for use in said dispenser and method.

Field of the invention:

The present invention relates to a quantity sensing device for sensing the quantity of sheet material in a substantially cylindrical sheet material supply roll having a sheet material supply outer surface diameter, wherein the sheet material is stored in a rolled configuration, such as that used in an automatic dispenser incorporating a preferably motor-driven dispensing system combined with control circuitry for same. Such a quantity sensing device may be used together with a warning means to indicate that the sheet material supply may need to be replenished.

The invention furthermore relates to a dispenser, preferably an automatic dispenser, including said sheet material sensing device.

The invention also relates to a product supply roll preferably adapted for use in a dispenser and method of the type described' herein.

Automatic dispensers, with sheet material stored in some part of the dispenser in the form of a supply roll of wound sheet material, normally wound around a core, are known for dispensing e.g. paper towelling, whereby the dispensed towel can be torn off. Such dispensers are often of the electrically powered type, preferably electrically-powered by means of one or more .batteries

(but which could also be AC powered or powered by a combination of AC and DC power supplies) . These dispensers may also contain user-sensing systems which cause dispensing of paper towelling or other sheet material from the dispenser when the presence of a user is detected. Such a sensor system may be a photo-sensor system, a capacitative sensor system, an active or passive IR sensor system which operates to control dispensing of products such as paper sheets (e.g. paper to be used as hand-towels) . When the presence of a user is detected, preferably without requiring physical contact of the user with the dispenser or sensors, the

(paper) sheet material is dispensed.

The rolls of paper or other sheet material in such machines are dispensed over a period of time and are monitored occasionally by attendant staff, for example in case they have become jammed or have to be refilled. Some dispensers are thus provided with one or more indicators indicating e.g. the need to refill the machine with a new towel roll. The indicators may be mechanically-moving devices (e.g. mechanical follower devices - see below) indicating low paper or automatic devices (e.g. electronically controlled) indicating that paper has been used up.

Background to the invention:

A dispenser of the aforementioned type is known for example from US-B1-6695246. This document discloses a paper sensing means in the form of a low paper indicator, comprising a cylindrical follower element intended to rest against the outer surface of the sheet material supply roll and able to move along a somewhat vertically arranged slot, whereby the follower is intended to move down the slot as the paper supply roll reduces in diameter. Paper is dispensed from the dispenser by means of motor rotation, and this will dispense some 25 to 30 cm of paper each time the motor is actuated.

Such a low paper indicating device suffers from the disadvantage that the follower/slot mechanism relies on low friction between the contacting surfaces of the slot and follower respectively. The follower may however become jammed in the slot during operation e.g. upon tilting of the follower or due to dirt on the surfaces or the like. Even if some resilient means were to be added so as to force the follower downwards, such devices are also prone to wear and failure over time and may not always overcome the problems of jamming due to tilting. Likewise, a mechanical follower must be manually raised in the guide slot to a sufficient height upon paper roll insertion in order to contact the paper roll outer surface. Furthermore such a device does not allow the amount of remaining sheet material to be ascertained with any accuracy.

The present invention has as one of its objects, the provision of a sensing device which overcomes at least some of the problems indicated above.

A further object of the invention is to provide a simple means by which the amount of sheet material remaining on a supply roll can be reliably, easily and accurately measured.

Further objects of the invention will be apparent upon reading this specification.

Summary of the invention: The main object of the invention is achieved by a sensing device having the features defined in claim 1. Certain preferred features of the invention are defined in the dependent claims .

Further features of the invention will be apparent to the reader of this specification.

Any locations on the dispenser are defined with respect to the dispenser in its normal position of use and not mounted upside down or the like. Thus, the lower part of the dispenser is intended to be at the bottom when mounted. Likewise the lateral direction of the dispenser is in a generally horizontal direction.

Brief description of the drawings:

The invention will now be explained in more detail with reference to certain non-limiting embodiments thereof and with the aid of the accompanying drawings, in which:

Fig. 1 shows a simplified schematic side view of a dispenser,

Fig. 2 shows the drive roller and supply roll of Fig.l in a front sectional view, with further schematically shown simplified devices useful for understanding the invention,

Fig. 3 shows a detail of the slotted wheel from Fig. 2.

Fig. 4 shows a simplified drawing of the drive roller and supply roll indicating the parameters to be used in making various calculations, Fig. 5 shows a block diagram of elements of a simplified control system for use with a dispenser in which the invention can be used,

Fig. 6 shows a perspective view of a supply roll 7 provided with an end cap including dark and light sectors,

Fig. 7 shows a cross-sectional view through an end plug including dark and light areas, placed within one end part of the core portion of a supply roll.

Detailed description of preferred embodiments:

Fig. 1 show a dispenser 1, having an upper front wall 2, top wall 3, rear wall 4, lower front wall 5 and a lower wall 6, which walls together form the panels of the dispenser 1 housing. Each of walls 5 and 6 is provided at its base portion with a mounting area on which sensors 13 and 14 of a user-detection sensor system have been placed, whereby a dispensing outlet has been arranged to lie between panels 5 and 6 for allowing dispensing of a sheet material 17 therethrough. A cutting blade edge 12 is also provided just proximate the outlet in order that dispensed sheet material (e.g. non-perforated sheet material) may be drawn against said edge 12 for cutting and then removing a portion of said sheet material from the remainder of the sheet material held in the dispenser.

The dispenser is intended to be attached to a stationary object (e.g. a wall) in the orientation shown in the drawing, whereby the rear wall 4 is preferably mounted so 49

as to be generally vertical and whereby a supply roll 7 of sheet material 17 and its generally rotationally central core portion 8 is mounted generally horizontally. Likewise, drive roller 9 which is fixedly mounted on shaft 15, is located below said supply roll 7 and also generally parallel thereto. Other orientations are however possible, such as vertical orientations of each of the roll 7 and roller 9.

The sheet material supply roll 7 has a hollow central core portion 8 around which the sheet material 17 is wound (i.e. in the form of a spiral) . In the case shown, the sheet material is e.g. paper towelling which has been wound around a core portion 8 made of, for example, cardboard or plastics. The sheet material may however be any suitable flexible material, e.g. cloth or plastic film, preferably of substantially non-elastic material.

The sheet material 17 is suitably a roll of continuous non-perforated sheet material such as non-perforated paper material, but may also comprise perforated sheet material such as perforated paper sheet material. Such a roll is preferably generally cylindrical.

Although the (paper) roll has been shown with a physical core portion 8, made of e.g. cardboard, it should be understood that the invention can also be used with coreless rolls (not shown) whereby the "core portion" should be understood to be the diameter of the inner cylindrical space of the supply roll 7. Such can be produced by the sheet material 17 being wound around a removable core or former which core or former is removed after manufacture, whereby the supply roll can be delivered to the end user without a physical core and is then mounted in the housing (for rotation therein) by means present in the housing itself to support at least both vertical ends of the core portion 8 opening.

The drive roller 9 is preferably substantially cylindrical and suitably made of rubber material or another material able to reliably feed the sheet material 17 when rotated, whilst nipping the sheet material 17 between the outer surface of drive roller 9 and a pressure roller 10 mounted preferably parallel to and in pressure contact with drive roller 9. Such an arrangement of drive roller 9 and pressure roller 10 is well known per se for applications of driving sheet material through the nip formed therebetween upon rotation of drive roller 9. In the shown embodiment, drive roller 9 has a rotation shaft 15 fixedly located therein (e.g. by the rubber being moulded directly on to the shaft 15) .

Drive roller 9 is driven by means of a motor M, shown schematically joined to roller 9 in Fig. 1. In Fig. 2, it is schematically shown that motor M has a gear 20 at one end which meshes with a gear 21 which is fixedly attached to shaft 15. The gearing is schematically shown and may be a reduction gearing, depending on the motor speed characteristics.

The drive roller 9 is supported in the housing by means of supports (not shown) for rotation with respect to the housing. In one possible embodiment, the drive roller 9, motor- M and pressure roller 10 may form some of the elements of a modular cassette (not shown) which can be removed as a modular unit from the dispenser housing. In this case, the mountings (not shown) for the shaft 9 would then preferably be in the modular cassette housing. When motor M is activated this causes drive roller 9 to rotate and to draw sheet material 17 through the nip of pressure roller 10 and drive roller 9. In turn, this causes the supply roll 7 to rotate, causing sheet material 17 to be unwound from the supply roll 7. It is this induced rotation of the supply roll which can be put to practical use in determining the quantity of material on the supply roll 7, as will be explained below.

The supply roll 7 is mounted in the dispenser 1 housing itself (this is also the case where a modular cassette is used as described above, since the supply roll 7 is not included in a modular cassette) . For this purpose, in one embodiment, an insert 22, e.g. of plastic or metal, is fixedly located e.g. by a push fit or a glued fit, inside the core portion 8. The insert 22 has, in the embodiment depicted, a small stub shaft which can be located in a receiving surface (not shown) for same located on an internal side wall of the dispenser housing so as to allow rotation with respect thereto. Such an arrangement is already known per se e.g. from the supply rolls provided for use with Intuition II dispensers distributed by SCA Tissue North America LLC in Wisconsin USA.

In Fig.2 at the right hand end of the supply roll 7, there is depicted a rotatable member 18 having a conical end portion at its left hand end. The conical end portion forms a frictional push fit with the supply roll 7 core portion 8 such that the rotatable member 18 can be rotated without slip with respect to the core portion 8 (or thereby supply roll 7) . This rotatable member 18 is rotatably mounted by means of e.g. a shaft 19 with respect to a sidewall of the dispenser housing. Thus, when the supply roll 7 is in the position shown in Fig. 2, the entire assembly 7, 22 and 18 rotates together. The rotatable member 18 and the insert 22 may of course be placed at opposite ends of the roll 7 than depicted. Likewise, the insert 22 may for example be replaced by a means projecting from the housing into the core portion 8 so as to permit rotation of the supply roll 7.

Attached to the right hand end of shaft 15 is a means for measuring the amount of rotation of the shaft and thereby also roller 9 (as the shaft 15 is rotationally fixed in the roller 9) . In the shown embodiment, a disc 23 is depicted as being mounted for rotation with shaft 15, such that no slip exists between the shaft 15 and the disc 23. The disc 23 has slots 29 (see Fig. 3) or other markings located at equal angular spacing. In the embodiment shown, eight slots 29 are provided, although any suitable number may be used depending on the accuracy required, whereby the higher the number of slots 29 the higher the accuracy that can obtained. A suitable number may lie between eight and twenty slots 29 for example. A slot detection device 24 is fixedly located with respect to the dispenser housing (or the modular cassette if present) in such a way that slots 29 passing the slot detection device 24 will be individually detected. Such a slot detection device is well known per se for example in the form of a rotary encoder. Typically this comprises a photo-interrupter system detecting the passing of the slots 29. Thus, for example, in the case of an eight slotted disc rotating half a turn, the detection device 24 detects the passing of four slots 29. The amount of rotation detected is passed down line 25 to a control means 31 able to compare the amount of rotation of roller 9 to another value (see below) . This may be means of a comparator block. In its most simple form, the rotary encoder sends a single voltage pulse down the line 25 whenever a slot 29 passes. Since the diameter d of drive roller 9 is fixed, and assuming no sheet material 17 slippage occurs in the nip between rollers 9 and 10, the number of slots 29 passing the detection device 24 is a direct measure of the length of the sheet material 17

(e.g. paper) dispensed.

Likewise a further rotation detector is present for determining the amount of rotation of rotatable member 18. This comprises, in a similar manner to the driver roller 9, a rotary encoder. In the embodiment shown, this includes a slotted member in the form of a cylindrical portion 26 containing slots 33 joined to the conical portion of rotatable member 18 and shaft 19. The passing of the slots 33 is picked up by the stationary portion, a slot detector 27, which may be formed in the same way as for the drive roller 9, thus sending a voltage pulse down line 28 each time the shaft 19 rotates an amount sufficient to cause a slot 33 to pass the slot detector 27.

The number of slots 29, 33 on each encoder is preferably the same, for purposes of simplicity. Thus there may for example be sixteen slots 29 on disc 23 and sixteen slots 33 on hollow cylindrical portion 26. In this way, the amount of rotation of the supply roll 7 and the amount of rotation of the driver roller 9 can be compared simply as a ratio of the number of slots detected as passing each fixed slot detection device 23 and 27. If the number of slots 29, 33 (or other detectable markings) is different for the drive roller encoder and supply roll encoder respectively, this must obviously be taken into account as will be readily apparent from the description of the comparison and calculations shown further below.

As is further shown in Fig. 2, the outer diameter of the supply roll is denoted as D_n. The diameter D_n is an alterable diameter, which alters as the sheet material

17 thereon is unwound during dispensing, "n" is the separation level of the paper sheet (i.e. the level of a layer of material within the wound supply sheet material from the core portion 8) .

The outer diameter of the core portion 8 is denoted as D₀. D₀ is fixed and known for any particular supply roll. Such a value may be stored in the control system of the device, or it can be measured and entered in the control device (e.g. by means of a keyboard or other entry panel - not shown) .

The situation depicted in Fig. 4 is a further simplified side view of the drive roller 9 and the supply roll 7. Using this Figure, it will be seen that the amount of rotation of the supply roll 7 and the drive roller 9 can be arrived at by the following equation:

((π D_n / N₁)) x P₁ = ((π d / N₂)) x P₂ (1)

where :

D_n = outer diameter of the supply roll 7 (variable) d = outer diameter of drive roller 9 (fixed) N₁ = number of slots for encoder on supply roll 7 N₂ = number of slots for encoder on drive roller 9 P₁ = pulse count (no. of passing slots) of drive roller 9 in a specific time period P₂ = pulse count (no. of passing slots) of supply roll 7 in the same specific time period as for P₁.

If the number of slots on the encoders (disc 23 and cylindrical portion 26 in the embodiment described above) is equal, then Ni = N₂ (if not equal, this may be accounted for by the appropriate ratio factor of the number of slots in each encoder)

Removing the common factors from equation (1) gives:

D_n . P₁ = d . P₂ (2)

Thus D_n / d = P₂ / P₁ (3)

Thus the diameter D_n (at any separation level n of the sheet material 17) of the supply roll 7 can be calculated, based on the number of pulses during the last period of rotation, received from the respective encoders, during movement of the supply roll 7 and the drive roller 9, because the diameter d of the drive roller 9 is fixed.

The ratio of P₂ / Pi can be provided by a comparator in the control means 31 (e.g. the encoder signals are input and then software calculates and causes output of a signal, whereby the comparator may be in software or in hardware) . Likewise the quantity of paper remaining on the supply roll can be determined, when the thickness T is known for the sheet material 17 (see further below) .

Due to the fact that the ratio P₂/Pi changes to a smaller and smaller value as the supply roll 7 becomes more and more depleted (i.e. the angular rotation speed or pulse number or the number Pi of slots 33 passing the encoder, during any time period of rotation of the drive roller 9, increases gradually as the sheet material 17 depletes) , this factor P2/P1 can be compared to a threshold value. When P₂/P₁ passes the threshold value (in this case by going from a value "greater than" to a value "less than" the threshold) , this can be used as a warning that paper has reached a predetermined minimum quantity.

Thus, comparison circuitry in the control means 31 (e.g. a differential comparator) can be used to compare the ratio P₂ / Pi to the chosen threshold and then output a voltage signal 32 indicative of the threshold having been passed. Alternatively a signal of another type (e.g. a digital signal) indicative of the threshold having been passed could be used. This voltage, or other, signal can be used to trigger a warning circuit 34 in the dispenser, such that a visual display is provided to an attendant. For example a lamp (e.g. a yellow lamp) might be lit when the threshold is passed, thus signifying a particular quantity of sheet material remaining in the device. Such a warning could additionally or alternatively be audible.

Several differing thresholds may be set in the dispenser, for example a first threshold as above, followed by a second threshold, which when exceeded activates a further visual and/or audible warning. Still further levels could be included if desired.

Alternatively or additionally, a display (e.g. a display panel - not shown) could be included, whereby the quantity of sheet material 17 remaining in the dispenser 1 would be indicated on a continuous or intermittent basis. Such a display could for example indicate the remaining length of sheet product or (in a paper towel dispenser) the number of remaining towels until total depletion based on towels of a predetermined length being dispensed (as determined by the set angular rotation of the motor M in a dispensing cycle) .

Using Fig. 4, the explanation below shows how the calculation of ratio of P₂ / Pi is performed which is suitable to be used as the point at which a threshold is passed to give an indication of low amount of sheet material .

Values and symbols are unchanged from those defined previously.

D₀ = 4cm (which is an individual known and predetermined value for any particular supply roll, in this case one of 4cm core portion 8 outer diameter - and which roll a dispenser will generally use all the time - this value may also be settable in the quantity sensor control means of the dispenser to allow for different core portion 8 outer diameters) .

T = Thickness of sheet material. With reference to paper type 290056 this value is 0.013cm (again this is an individual value known and predetermined for each supply roll value and may also be settable in the quantity sensor control means of the dispenser to allow for different thickness of sheet material in any supply roll) .

n = Separation level of sheet material d = 2.5cm (this value for the drive roller diameter is fixed for any particular drive roller) The value D_n can be expressed as D_n =D₀ + 2nT (4)

The total sheet material 17 length ^λλL" remaining at the supply roll 7 to be dispensed at a "paper low" alert warning, is the individual sheet material length set in the control means (e.g. via a control panel) for the amount of sheet material to be dispensed at one dispenser actuation occasion, multiplied by the desired remaining number of pieces of sheet material to be dispensed before total depletion. Thus:

L = sheet material length set x 50 remaining pieces (5)

=Doπ + Din + D₂π + + D_nπ (for a circumference of the supply roll varying from D₀ to D_n) L = (D_{0 +} Di + + D_n) π (6)

= (D₀ + D₀ + 2T + + D₀ +2nT) π (7)

= [nDo + 2T(I + 2 + +n)]π (8)

= [nD₀ + T(I + n)n]π (9)

= [Tn² + Tn + nD₀]π (10) == [Tn² + (T + D₀) n]π (11)

This provides an equation in the form to allow n to be calculated as:

Tn² + (T + D₀) n - L/π = 0 (12)

Solving the equation (12) gives N as:

n = {-(T+D_o)± sqrt [(T + D₀)² - 4TL/π]}/2T (13) This can be used for example for individual sheet material piece lengths in the range of 20cm to 50cm as shown in the table below) .

n will be found and determined for D_n from equation (4) . The ratio of P2/P1 is the same as the ratio D_n /d for the set range of L is shown in the table below, values having been calculated at 5 cm intervals of individual sheet piece length. Smaller intervals could be used of course.

Dimensions are measured in cm

The pulse/cm value of the rotary encoder for the drive roller 9 is chosen as 0.436.

Using the table above, e.g. by storing this table as a series of values e.g. in an array in a memory portion of a control means 31, a predetermined P₂/Pi ratio value can be set as a threshold at which a low paper is determined to exist, and when the P₂/P1 ratio passes this value, a warning can be given. Also, from the above calculations and any stored table for a particular supply roll and driver roller combination, the exact paper length remaining can be determined for each value of the P₂/P₁ ratio. Thus, the ratio can also be used to trigger a constant or intermittent display (not shown) of the remaining length, or even a series of warnings as different threshold values are passed.

The drive roller 9 may suitably be powered by batteries (not shown) located in the dispenser 1. Suitable batteries may supply a total of 6V when new and typically four 1.5V batteries are suitable for this purpose.

Exemplary of suitable types are Duracell/ s MN1300 batteries whereby each battery has a capacity of 13Ah and which can operate from full to total discharge between the range of 1.5V to 0.8V.

The motor M is at rest and without power applied to it when no paper is to be dispensed. The motor M is rotated when paper is to be dispensed through the discharge opening 16. The operation of the motor M is controlled by a master control unit (see Fig. 5) . This may be connected to a user-sensing system comprising, in the shown embodiment in Fig. 1, one or more sensors, such as sensors 13 and 14. The one or more sensors 13 may for example be IR emitters and one or more sensors 14 may be IR receivers (e.g. diode structures).

The dispenser 1, upon detection of a possible user, and preferably without any contact of the user with the dispenser or the sensors 13, 14, thus causes the dispenser 1 to dispense a product. Dispensing in this case is performed by the front portion 30 of the sheet material 17 being discharged automatically (by rotation of the motor M) through discharge opening 16 which is normally a horizontally and laterally extending opening, in the lower part of the housing, and preferably feeding out downwards .

The emitters 13 of an optional user-sensing system may be arranged via suitable control circuitry, which may control circuitry as known per se in the art, to emit pulsed IR at a narrow frequency band of for example about 15kHz ±0.5%. The receivers 14 may then be arranged to detect the emitted IR which is reflected against objects (stationary or moving) back towards the receivers. The IR receivers are preferably tuned to the frequency of the emitters to suppress IR outside the expected frequency range (12 to 18 kHz) of the reflected waves and to amplify the IR at the 15 kHz range level.

As stated previously however, other user detection systems may be used rather than active IR, such as passive IR, capacitative or other systems. Furthermore, the invention can operate of course without such a user detection system, whereby a fresh piece of sheet material is dispensed automatically when a previous piece of sheet material has been removed to be left hanging for grasping by a user (in paper towel dispensers this is often termed the "hanging towel" mode) .

Fig. 5 shows a block diagram of the basic system of one embodiment of a dispenser according to the invention, in which a user sensing system is included. The portion shown in dotted lines includes the basic components for IR signal modulation (when this is present) , IR emission and IR reception used to submit a sensing signal to the 005/013449

19

A/D modulation of the master control unit (MCU) which contains a microprocessor.

Box 101 and 102 denote IR emitter (s) and receiver (s) respectively. The hand shown outside the dotted lines indicates that IR radiation emitted by the emitter (s) 101 is reflected by the hand back to receiver (s) 102. Unit 103 is a photo-electric converter for converting the received IR signal before it is passed to filtering and amplification unit 104 where band pass filter and amplification circuits operate to amplify the received signal around the central frequency in a limited band width and to thereby suppress other IR frequencies relatively. The signal is then passed to a signal rectification unit 105, since the IR signal is an AC signal. From the unit 105, the signal passes into the A/D module of the MCU.

The output of the pulse width module (PWM module) 106 is controlled by the MCU such that a square wave signal from the PWM can have its duty cycle varied by the MCU to adjust the DC voltage to the emitter circuits and thus the power of the IR signal emitted. The PWM 106 is connected to a D/A converter 107 and into an IR emitter driving circuitry unit 109 which includes e.g. a constant current sink. Into the same IR emitter driving circuitry is also fed a signal from a phase frequency detection module 108 which issues, in the case of an active IR emitter sensor system as mentioned above, a 15kHz (+0.5%) impulse modulated signal so as to drive the emitters 101 via the emitter driving circuitry 109 to emit modulated

IR signals for short intervals. The signal from unit 109 feeds into the IR emitter on/off control unit 110. The input/output module 118 of the MCU also feeds into the unit 110 to be turned on and off as required to thereby perform an IR scan via the emitter 101.

In order to activate the microprocessor, RC wake-up circuitry 115 may feed into the MCU into a wake-up detection unit 114. Unit 117 is an external interrupt detection unit .

From the input/output module 118 is a feed to unit 119 which can be regarded as the motor driving circuitry which drives the motor M when a product should be dispensed. In the case of a hanging towel mode, motor M should operate only when one towel sheet has been dispensed and removed.

Further peripheral units 111, 112 are respectively a paper sensing circuit unit (e.g. for paper present at the outlet) and a low power detection circuit (i.e. for detecting batteries close to depletion) . Unit 116 indicates battery power used to drive the MCU and also all other peripherals and the motor M. Unit 120 may be motor-overload circuitry which cuts off power to the motor for example when sheet material becomes jammed in the dispenser or when there is no sheet material left in the dispenser. Unit 121 is a sheet material length control unit (for setting the length of an individual piece of sheet material as denoted in the first column of the table above) , which operates such that a constant length of sheet material (which can itself be variably adjustable by manual operation e.g. of a variable resistor or the like) is dispensed each time the motor M EP2005/013449

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is made to operate to dispense a length of sheet material

(e.g. paper sheet) through the discharge opening 16. This unit 121 is preferably a pulse position control system

(as described above with respect to the use of a rotary encoder) whereby the rotation of the motor M output shaft or the drive roller shaft 15, or other item in the drive power train, is counted in a series of pulses and the rotation is stopped only when the exact number of pulses has been achieved. Since driver roller 9 has a constant diameter d, this ensures that the same quantity is dispensed each time. Since the drive roller 9 and supply roll 7 rotation measurement system already uses rotary encoders of this type, ^' no additional rotary encoder is therefore required for the length control.

Unit 122 may be the low paper detection circuitry as described above, which thereby could include the control^' means 31, which unit 122 feeds into the input/output circuitry 118. Unit 123 may be used to indicate whether the dispenser casing is open or closed. As apparent, the signal 32 shown as output from the control means 31 may clearly pass through the input/output unit 118 before being issued as a warning.

One or more warning or even status indication lights may be associated for example with various units^' such as units 111, 112, 120 to 123 to indicate particular conditions to a potential user or dispenser attendant

(e.g. if the dispenser needs refilling with paper in the case where the ratio P2/P1 has passed one or more set threshold values) .

The invention is not limited to the embodiments and variations thereof described above. For example, the rotatable member 18 and the rotational measurement may take many different forms. Likewise the control means 31 and its interaction, or not, with other control circuitry (Fig. 5) described for dispensing sheet material may be arranged differently than indicated.

While the device has been explained in relation to a dispenser where sheet material 17 is dispensed and then removed (e.g. an automatic paper towel dispenser), the invention is equally applicable to cloth towel dispensers, where instead of the material being removed, it is withdrawn again back into the dispenser housing.

As an alternative to the use of a slotted member 26 attached to, or forming part of, the rotatable member 18 as heretofore described, a supply roll 7 itself may be provided on one or both of its end faces with rotationally angularly-equal repeating pattern of suitably two different colours, or different materials, for example. Said repeating pattern should preferably include at least two distinctive patterns separated by two other distinctive patterns. For example the patterns may be two dark sections or areas and two light sections or areas. Preferably, more than two of each area may be used, such as three or four dark areas with an equal number of light areas in between the dark areas or sections. A number greater than four can also be used

(e.g. five dark areas and five light areas). The pattern may also be formed by including a metal spoke or projection between non-metallic areas (e.g. plastic or cardboard areas, such as a plastic disc with circumferentially equally spaced metal portions) . The words "dark" and "light" are relative to each other, but preferably the dark and light areas should be easily- distinguishable from each other in terms of the amount IR radiation reflected from same, e.g. providing a difference of greater than 10% and more preferably a difference in the range of 10 to 50% or more. More preferably such areas or sections may be generally black and generally white areas or sections. In terms of the different materials which could be used in certain embodiments, the materials should be such that one of the materials can be distinguished from the other by means of a detector (e.g. a metal detector detecting the intermittent passing of metallic elements in a cardboard or plastics body by means of electromagnetic field changes, as the cardboard or plastics body rotates) .

Such a pattern including e.g. dark and light areas or different materials, is a pattern where the dark and light areas (and/or different materials) are positioned with equal angular spacing, whereby the dark and/or light areas, and/or at least one of said different materials, are positioned at equal angular spacing on said roll end face .

For this purpose, such a supply roll 7 may be supplied with a fixedly mounted, or removably mounted, plug 36 therein (see Fig. 7), or merely an end cap 43 (Fig. 6), with or without projections into the core portion 8.

The plug 36 or end cap 43 may be fixedly or removably mounted on to the end face, preferably by being attached to the core portion 8, for use in a dispenser with a means for detecting rotation of said roll 7 (by means of said pattern) , which plug 36 or end cap 43 is mounted preferably rotationally generally concentrically with respect to the central rotational axis of the supply roll, i.e. the central rotational axis of the core portion 8 (see e.g. Fig. 6 or 7) , at least at one end of the supply roll 7. Such a plug may also be similar in shape to insert 22 described previously.

This plug 36 or end cap 43, may itself contain a stub shaft portion 38, similar to shaft 19 (shown in the previous embodiments for the member 18), whereby such shaft portion 38 could then be mounted on a support surface (not shown) of the housing for rotation with respect thereto -when the roll 7 (with attached plug or end cap) is placed in the housing. Alternatively, the plug or end cap, could be provided merely with a means (e.g. a hollow centre 42) through which means a shaft (not shown), e.g. a shaft rotationally fixed with respect to the housing (possibly retractable against a spring force) , is passed when loading a supply roll into the dispenser, to thereby support that particular end of the supply roll. In other embodiments (not shown), the latter-mentioned shaft could extend all the way through the supply roll 7 and, optionally, be mounted with respect to the housing at the other end of the supply roll.

Using such a plug 36 or end cap 43, as described above, the plug itself would need to be provided with means for recording its rotational movement (angular rotation) . As an option to the rotary encoder 27 described previously, for slotted member 26, the plug 36, or end cap 43, could have dark areas, sections or sectors 41 and light sections or sectors 37 thereon (e.g. black and white sectors) , whereby the dark and the light sections or sectors are circumferentially equally spaced, or wherein at least all of the dark (or light) sections or sectors to be detected are equally circumferentially spaced, whereby the movement of the dark 41 (or light 37) sections or sectors (and/or different materials where these are present) is detected by a rotary encoder 39 facing the sections or sectors which detects the passing of the dark (and/or light) sectors and/or the passing of the different material sections (e.g. metallic areas in a non-metallic plug or end cap body) . Such encoders may for example comprise a photodiode issuing a focussed IR beam, whereby the IR reflection from the individual dark and light areas is detected by means of an IR (e.g. photodiode) receiver. The dark and light areas clearly give different IR reflections, which are thus detectable as they pass the IR receiver and which can be passed through a threshold comparator thereby providing a voltage pulse when the threshold is exceeded (i.e. each time a light area passes the IR receiver) .

The words sector/sections/areas are herein use generally synonymously to indicate repeating or spaced "portions".

Such an encoder 39 as above described would then otherwise operate in the same way as encoder 27 with respect to the control means 31 described previously, whereby the signal from the encoder 39 would be passed to control means 31 down line 40. Other arrangements are also possible, whereby circumferentially equally spaced markings or shapes or materials are detectable as they rotate.

As shown in Fig. 6, the outer diameter of the end cap 43 is larger than the core portion 8. As will be evident, such an end cap may have surfaces which can be fixed by adhesive or other means to a physical core portion 8 at its outer end. The end cap may however be of generally the same outer diameter as the core portion 8. It may also be differently formed, e.g. in the form of a pointed star-shaped element (e.g. sheriff-star type), rather than having a completely circular periphery.

In the plug shown in Fig. 7, the plug 36 has a portion 44 thereof of reduced diameter, which extends into an end of the core portion 8 of the supply roll 7. Only one end part of the core portion 8 is shown. This allows the plug to be stably fixed within the core portion, such as by a push fit against the inside surface of the core portion 8 and/or by fixing means such as adhesive (not shown) . The enlarged portion 45 of the plug 36 may be alternatively or additionally be attached to the outer end face of the core portion 8 using for example adhesive. However other forms of plug may be used without requiring different diameter portions such as portions 44 and 45, or with additional portions.

Likewise the dark and light sections or sectors 37, 38 have been shown on the end face of the plug or cap. They may also be placed on another external rotating surface, such as on the radially outermost surface of enlarged portion 45.

The shaft 38 projecting from the plug 36 may be fixed to the plug 36 either by being fixedly attached thereto or being made in one piece therewith. Alternatively the shaft 38 may be non-attached to the plug and instead be mounted on the housing for removable mounting of the plug 36 thereon (e.g. by a cylindrical recess, not shown, in the centre of plug 36) .

The use of such a plug 36 or end cap 43, also has the additional advantage that the end of the roll 7 where this is mounted can give support against the roll being crushed or being otherwise deformed, which is of particular advantage when the core portion is of thin cardboard or other thin relatively weak material.

Roller 9 could also, or alternatively, be arranged to have such a rotary means as just described (i.e. with light and dark sections or sectors or the like) which can be detected by a rotary encoder, similar to encoder 39.

Claims

1. A quantity sensing device for sensing quantity of sheet material (17) stored as a substantially cylindrical sheet material supply roll (7) of outer surface diameter (D_n) , said device comprising a cylindrical drive roller (9) having an outer diameter (d) , and a rotatable member (18) adapted to rotate when said supply roll (7) is rotated, wherein said device further includes a control means (31) which is arranged to compare the amount of rotation of the drive roller (9) to the amount of rotation of the rotatable member (18) during the same time period.

2. A quantity sensing device according to claim 1, wherein said control means (31) outputs a result of the ratio (P₁/P₂ or D_n/d) of the amount of rotation of the drive roller (7) to the amount of rotation of the rotatable member (18) .

3. A quantity sensing device according to claim 1 or 2, wherein a first detection device (27) is provided to detect the amount of rotation of said rotatable member (18), and wherein a second detection device (24) is provided to detect the amount of rotation of said drive roller (9) .

4. A quantity sensing device according to claim 3, wherein said first detection device (27) is a pulse output counter device and/or said second detection device (24) is a pulse output counter device.

5. A quantity sensing device according to claim 3 or 4, wherein said first detection device (27) and/or said second detection device (24) is a photoelectric encoder.

6. A quantity sensing device according to claim 5, wherein each of said first and second detection devices (27; 24) is a photoelectric encoder, and wherein each of said photoelectric encoders includes a rotational slotted member (26; 23) arranged for rotation with said rotatable member (18) and with said drive roller (9) respectively, and a fixedly located slot detection member (27; 24) detecting movement of slots (33, 29) during rotation of said respective slotted member (26, 23) .

7. A quantity sensing device according to claim 6, wherein said drive roller (9) includes a central shaft (15), and wherein said slotted member (23) is fixedly attached for rotation with said shaft (15) , and wherein said rotatable member (18) is arranged to support at least one end of a supply roll (7) .

8. A quantity sensing device according to any one of the preceding claims 2 to 7, further including a comparator for comparing the output ratio (P₁/P2) of the amount of rotation of the drive roller (7) to the amount of rotation of the rotatable member

(18) to a threshold value, and emitting a first signal (32) when said threshold is passed.

9. A quantity sensing device according to claim 8, in which said first signal (32) is arranged to activate at least one warning indicator (34).

10. A dispenser (1) for dispensing sheet material (17) stored as a supply within said dispenser (1) , wherein said dispenser includes a quantity sensing device according to any one of the preceding claims .

11. A dispenser (1) according to claim 10, wherein a drive motor (M) is operably connected to said drive roller (9) to drive said drive roller (9), and wherein a pressure roller (10) is provided opposite said drive roller (9) so as to form a nip therebetween in order to allow sheet material (17) placed within said nip to be fed out of said nip upon rotation of the drive roller (9) .

12. A dispenser according to claim 10 or 11, wherein control means (121) are provided, said control means (121) being arranged to control the amount of rotation of said drive roller (9) for dispensing a predetermined amount of sheet material (17).

13. A method of determining the quantity of sheet material (17) remaining on a sheet material supply roll (7) having an outer diameter (D_n), in which said sheet material supply roll (7) is arranged to rotate due to rotation of a cylindrical drive roller (9) having a fixed outer diameter (d) , wherein a control means (32) compares the amount of rotation of the drive roller (9) to the amount of rotation of the sheet material supply roll (7), for rotation measured during the time of rotation of the drive roller (9) , and further produces a comparison result (P₁/P₂) which is equal to the ratio of the diameters (D_n/d) at said time of rotation of the drive roller (9) .

14. A method according to claim 13, in which the control means calculates the ratio of the diameters (D_n/d) based on the number of pulses (P₂) received from a second rotary encoder (23, 24) which measures the amount of rotation of the drive roller

(9), and based on the number of pulses (Pi) received from a first rotary encoder (26, 27) which measures the amount of rotation of the supply roll (7).

15. A method according to claim 14, wherein each of said first and said second rotary encoders (26, 27; 23, 24) each supplies a predetermined number of pulses for each complete rotation of said drive roller (9) and said supply roll (7) .

16. A method according to claim 15, wherein said predetermined number of pulses for each complete rotation is the same for each of said first and second rotary encoders (26, 27; 23, 24), and wherein the control means (31) determines the numerical value of the ratio of the diameters D_n/d to be equal to P2/P1.

17. A method according to any one of claims 13 to 16, wherein a signal is given when the numerical value of the ratio of the diameters (D_n/d) passes a threshold value which can be set in the control means (31) .

18. A method according to claim 17, wherein the value of the threshold is altered so as to set a different predetermined amount of sheet material which is to be present on the supply roll (7) for the signal (32) to be given.

19. Supply roll (7) of sheet material wound in a substantially circularly cylindrical outer surface and a first and second end face, said supply roll further including a core portion (8) generally at the centre thereof around which core portion said sheet material is wound, wherein at least one of said end faces is provided with angularly equally spaced areas (41, 37) of at least two different types, said spaced areas (41, 37) being fixedly located with respect to said end face for rotation therewith.

20. Supply roll (7) according to claim 19, wherein said spaced areas are respectively dark and light areas (41, 37) with respect to each other.

21. Supply roll (7) according to one of claims 19 or 20, wherein said two different types of areas are constituted respectively of a different material, whereby a first material for a first type of area is interposed between a second material for a second type of area.

22. Supply roll (7) according to claim 21, wherein said first material is metal and said second material is a non-metal.

23. Supply roll (7) according to any one of claims 19 to 22, wherein said at least one roll end face is provided with a plug (36) or end cap (43), said plug or end cap including said angularly equally- spaced areas (37, 41) of at least two different types.