Abstract:
A dispenser for dispensing folded sheets ( 160 ) of foil comprises first advancement means ( 119, 121 ) for controllably advancing a strip ( 161 ) of foil in a feed direction (F); folding means ( 147, 135, 139, 129 ) for folding a leading edge of said strip of foil ( 161 ); cutting means ( 141, 133 ) for cutting said strip ( 161 ) of foil to form a sheet ( 160 ) of foil; second advancement means ( 123, 125 ) for flattening the fold formed in the leading edge of said sheet ( 160 ) of foil and dispensing said folded sheet ( 160 ) of foil.

Description:
FIELD OF THE INVENTION 
     The present invention relates to method and apparatus for dispensing sheets of foil in which an edge of the sheet is folded. In particular, but not exclusively, it relates to method and apparatus for automatically dispensing sheets of foil ready for use in colouring hair. 
     BACKGROUND OF THE INVENTION 
     Devices for dispensing sheets of material from a roll are well known. In their simplest form the free end of the material is grasped and pulled manually. Once the required amount of material has been pulled free of the roll, the strip of material is torn on a serrated edge of the packaging containing the roll of material to form a sheet as required. Dispensers for semi-automatically dispensing a predetermined length of material are also known in which a motor drives rollers for advancing a sheet of predetermined length of material which can be manually torn on a serrated edge of the dispenser. 
     Using sheets of aluminium foil in colouring (highlighting) hair is well known. The process requires the hairdresser to pick up a pre-cut sheet of foil with one hand whilst holding the prepared section of hair with the other. The hairdresser must then fold the upper edge of the sheet whilst holding the prepared section of hair. This folded edge forms a solid edge to fit tightly under the roots of the prepared section of hair. The prepared section of hair lies on the sheet separated from the rest of the hair and the colour is brushed onto the prepared section of hair. The folded edge is important as it provides a tight fit to the roots of the coloured hair to avoid the colour “bleeding”. The process requires many sheets of foil which have to be pre-cut before the colouring process. Depending on the length of the hair to be coloured, different lengths of foils may be required. 
     Invariably, salons store the foils in pre-cut format which is inconvenient as the foil can become easily damaged or creased making them unsuitable for their purpose. In the manual and semi-automatic dispensers mentioned above, many sheets of foil have to be prepared before the colouring process and it is not possible for the hairdresser to predict the exact number of foils required for a particular treatment and therefore, inconveniently, the hairdresser may have too few or too many sheets of foil. 
     Further, such prior art dispensers do not provide completely prepared sheets of foil in that one edge of the sheet is not folded to provide the edge required for the roots of the hair. Therefore, in using such dispensers, the hairdresser is still required to fold the edge whilst holding the prepared section of hair which can be cumbersome as well as time consuming. 
     U.S. Pat. No. 6,602,177 provides a solution by providing a dispenser for automatically producing sheets of foil for hair colouring in which one edge is folded. The dispenser operates such that a strip of foil is fed from a roll by two pairs of nip rollers. A cutter and folding assembly is provided between the pairs of nip rollers. Firstly a sheet of foil is cut from the strip and the trailing edge of the sheet is folded by firstly pressing the edge into a vertical V-shape and folding down the upper edge of the V-shaped edge with a resilient roller and a knockdown table. The cut and folded sheet is then dispensed through the downstream pair of nip rollers. As the fold is formed in the trailing edge, the downstream nip rollers catch the fold, which can crease the fold further forming a multi-layered fold, and due to the bulk of the fold, the dispenser is inclined to jam. Alternatively the downstream nip rollers cause the fold to unfold. Furthermore the folding assembly comprises a press to form the V-shaped edge and a roller to crease and form the fold making the dispenser complex in design. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide a dispenser of sheets of foil having a folded edge in which the fold is form in line with the movement of the dispensing mechanism to prevent the device becoming jammed and to maintain integrity of the fold. It also seeks to provide a simplified mechanism for shaping and forming the fold. 
     This is achieved according to an aspect of the present invention by apparatus for dispensing folded sheets of foil, the apparatus comprising: first advancement means for controllably advancing a strip of foil in a feed direction; folding means for folding a leading edge of the strip of foil; cutting means for cutting the strip of foil to form a sheet of foil; second advancement means for flattening the fold formed in the leading edge of the sheet of foil and dispensing the folded sheet of foil. 
     This is also achieved according to another aspect of the present invention by a method for dispensing sheets of folded foil, the method comprising the steps of: advancing a strip of foil in a feed direction; folding a leading edge of the strip of foil; cutting the strip of foil to form a sheet of foil having the folded leading edge; flattening the fold formed in said leading edge of the sheet; and dispensing the folded sheet of foil. 
     As the fold is formed in the leading edge of the strip foil, the fold lies in line of the direction of feed of the strip of foil so that as the strip advances and is flattened, the fold will not crease causing a jam nor will it unfold. Furthermore, the fold can be simply flattened by the second advancement means which also dispenses the sheets, thus simplifying the apparatus. 
     Preferably, the folding means comprises a folding member, the folding member being raised to block the path of said strip of foil as said strip of foil advances in its feed direction, the folding member forcing the leading edge of the strip of foil upwardly and in a direction opposite to the feed direction of the strip of foil by a predetermined amount. More preferably, the folding member extends across the path of the strip of foil, the folding member having a generally U-shaped cross section, a first arm of the U-shaped member extending beyond a second arm of the U-shaped member, the second arm being pivotable about its proximal end, the outer surface of the base of the U-shaped member comprises a projection resting on the surface of a cam such that rotation of the cam rotates the U-shaped member about its pivot such that the first arm is raised and blocks the path of the strip of foil as the strip of foil advances. In order to provide a fold of a particular dimension the first arm may remain in the path of the advancing strip of foil for a predetermined time interval forcing the leading edge of the strip of foil upwardly and in a direction opposite to the feed direction of the strip of foil by the predetermined amount. 
     The U-shaped member provides a simple mechanism for folding the leading edge of the foil which can be simply raised and lowered as required by travelling the U-shaped member over the outer surface of a rotating cam. 
     In a preferred embodiment, the cutting means comprises a blade, the blade being raised vertically on the surface of a second cam to cut the strip of foil at predetermined intervals. The timings for raising the blade can be made to provide sheets of any desired length. 
     The first and second advancement means may comprise a first and second pair of driver rollers commonly driven by a motor so that the first and second advancement means are synchronised to advance the strip and formed sheets at the same speed. The first and second cams may be driven by a second motor. The first and second motor can be synchronised to provide folds and cuts as required to dispense sheets of a predetermined length having a fold of a predetermined size. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       For a more complete understanding of the present invention, reference is now made to the following description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a plan view of the casing of the dispenser with the lid in its closed position according to an embodiment of the present invention; 
         FIG. 2  is a side view of the dispenser showing the contents of the casing of the dispenser shown in  FIG. 1 ; 
         FIG. 3  is an end view of the casing in the direction of arrow A of the casing shown in  FIG. 1  showing the contents of the casing; 
         FIG. 4  is a side view of the dispenser of  FIG. 1  illustrating the loading of the roll of foil into the dispenser; 
         FIG. 5  is a simplified diagram of the drive rollers of the dispenser of  FIG. 1 ; 
         FIG. 6  is a simplified diagram of the cutting mechanism of the dispenser of  FIG. 1 ; and 
         FIGS. 7   a  to  7   d  illustrate the stages of the folding mechanism of the dispenser of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     An embodiment of the present invention will now be described in more detail with reference to  FIGS. 1 to 7   d . The dispenser  100  according to the embodiment of the present invention comprises a plastic casing  101 . The casing  101  comprises a base portion  103  and a lid  105 . The base portion  103  comprises a base and 4 sidewalls to form a generally rectangular box-like casing. The dispenser  100  is compact and completely portable. 
     The lid  105  is hingeably attached to the base portion  103  at one end thereof such that the lid can be pivoted upwardly from a closed position to an open position. The outer surface of the lid  105 , as shown in  FIG. 1 , comprises an interface control panel  107  and a release mechanism  109 . The release mechanism  109  comprises means for releasably engaging the lid  105  to the base portion  103  to seal the lid  105  to the base portion  103  when the lid  105  is in a closed position. The release mechanism  109  is disengaged to allow opening of the lid  105  as illustrated in  FIG. 4 . The interface control panel  107  comprises a plurality of push buttons  111   a ,  111   b ,  111   c ,  111   d  and  111   e  and a plurality of displays  113   a ,  113   b  and  113   c.    
     The base portion  105  of the casing  101  comprises a semi-spherical carrier  115  into which a roll of foil is seated. The semi-spherical carrier  115  comprises thumbnail indentations  117  so that the roll  159  can be easily grasped for subsequent removal. The carrier  115  supports multiple widths of rolls of foil by means of sliding devices within the carrier  115  to centre the roll  159  within the carrier  115 . The roll may be supported within the base portion  105  of the casing  101  by any alternative means such as a spindle or bung arrangement. 
     The casing  101  further comprises a first pair of drive rollers  119 ,  121  and a second pair of driver rollers  123 ,  125 . The second pair of driver rollers  123 ,  125  is positioned downstream of the first pair of driver rollers  119 , 121 . Each pair of driver rollers  119 ,  121  and  123 ,  125  comprise an upper driver roller  119  and  123  within the lid  105  of the casing  101  and lower driver roller  121  and  125  within the base portion  103  of the casing  101 . Each upper driver roller  119  and  123  are positioned directly above their respective lower driver rollers  121  and  1125 . The outer circumferential surface of the respective upper driver rollers  119  and  123  and lower driver rollers  121  and  125  are textured or covered with rubber etc. The base portion  103  also comprises a dispensing slot  108  downstream of the second pair of drive rollers  123  and  125 . The base portion  103  comprises a first motor  127  and a second motor  129 . These motors may comprise electric motors such as stepper motors or DC motors controlled by rotary shaft encoders. The motors are controlled by microprocessors (not shown here). If DC motors are used, sensors are added to detect the end of the foil. This may also provide an alarm to the user that the roll is empty. 
     The first motor  127  is attached to the first and second lower driver rollers  121  and  125  via a toothed drive belt  131 . 
     The base portion  103  of the casing  101  comprises a first cam  133  and a second cam  135 . The first and second cams  133  and  135  are connected to the second motor  129  via second and third drive belts  137  and  139 , respectively. The base portion  103  of the casing  101  comprises a vertically reciprocating cutter  141 . The lower end of the cutter  141  engages the surface of the first cam  133 . The upper end of the cutter  141  comprises a blade  143 . The blade slideably engages a guide  145  when the cutter  141  is in its raised position. The guide  145  is contained within the lid  105  of the casing  101 . The guide  145  is formed of a sharpening stone material so that the blade is self sharpening. 
     The base portion  103  of the casing  101  further comprises a folding member  147 . The folding member  147  extends transversely across the width of the path of the foil and has a generally U-shaped cross section. A first arm  151  of the folding member  147  extends beyond the second arm  153  of the folding member  147 . The proximal end of the first arm  151  extends inwardly. The proximal end of the second arm  153  of the folding member  147  is pivotably attached to the base portion  103  of the casing  101  at the pivot point  155 . The folding member  147  comprises a projection  157  having a generally triangular cross section and attached to the outer lower surface of the folding member  147  and resting on the outer surface of the second cam  135 . 
     Operation of the dispenser  100  of the preferred embodiment of the present invention will now be described in more detail with reference to  FIGS. 1 to 7   d.    
     The lid  105  of the casing  101  is placed in its open position as shown in  FIG. 4  by disengaging the release mechanism  109 . A roll  159  of a strip of foil  161 , to be dispensed, is placed in the semi-spherical carrier  115  such that the roll  159  rests upon the base of the semi-spherical carrier  115  and the strip of foil  161  unwinds from the roll  161  in an anti-clockwise direction, the free end  163  of the strip of foil  161  extending outwardly from the upper edge of the semi-spherical carrier  115 . The free end  163  of the strip  161  of foil extends over the lower driver rollers  121  and  125  and out of the housing  101  via the dispensing slot  108 . The lid  105  of the casing  101  is placed in its closed position until the release mechanism  109  of the lid  105  and the base portion  103  engages to seal the unit. 
     With the lid  105  in its closed position, the free end  163  of the strip  161  of foil is positioned between the upper driver rollers  119  and  123  and the lower driver rollers  121  and  125  as shown in  FIG. 5 . The first and second lower driver rollers  121  and  125  are driven by the drive belt  131  and the first motor  127  upon activation of the dispenser  100  via one of the push buttons  111   a ,  111   b ,  111   c ,  111   d  and  111   e . The first and second lower driver rollers  121  and  125  are driven to rotate in an anti-clockwise direction such that the free end  163  of the strip  161  of foil is controllably advanced from the roll  159  toward and out of the dispensing slot  108  of the casing  101  in a feed direction F. The strip  161  of foil advances in its feed direction by friction between the textured outer surfaces of the first upper and lower drive rollers and the second upper and lower drive rollers. The drive rollers are biased to provide advancement of the foil at a controlled speed without damaging or tearing the foil. 
     A length of foil as well as size of fold required by the user is specified via the push buttons  111   a ,  111   b ,  111   c ,  111   d  and  111   e  and displayed by one of the displays  113   a ,  113   b  and  113   c . As the specified length of strip  161  of foil passes over the driver rollers  119 ,  121 ,  123  and  125 , the first cam  133  rotates via the second motor  129  and drive belt  137  causing the cutter  141  to move upwards such that the blade  143  cuts the strip  161  of foil at the required length as shown in  FIG. 6 . The cutter  141  then lowers as the first cam  133  continues to rotate. The edge of the subsequent length of the strip  161  passes over the lowered cutter  141 . 
     As the strip  161  of foil passes over the cutter  141  it comes into contact with the first arm  151  of the folding member  147  which has been raised by the second cam  135  as it rotates. The edge of the strip  161  of foil follows the raised first arm  151  of the folding member  147  and folds back on itself as shown in  FIG. 7   a  by an amount, such as 15 mm, as set by the user via the push buttons  111   a  to  111   e . Once the specified amount of the strip  161  of foil has folded back, the first arm  151  of the folding member  147  lowers as shown in  FIG. 7   b . The folded end of the strip  161  continues to pass over the lowered folding member  147  and the folded end is driven through the second upper and lower driver rollers  123 ,  125  which flattens the fold as shown in  FIG. 7   c . As the required length of foil  161  passes over the lowered cutter  141 , the cutter  141  is raised and the required length of foil is cut to form a sheet  160  having a folded edge which is dispensed out of the casing  101  via the dispensing shot  108  as shown in  FIG. 7   d.    
     Therefore, in using the dispenser of the preferred embodiment of the present invention, the hairdresser has the dispenser unit close by and, single handed, merely presses a push button on the top of the device for a prepared sheet of foil to be dispensed. 
     Although a preferred embodiment of the present invention has been illustrated in the accompanying drawings and described in the foregoing description, it will be understood that the invention is not limited to the embodiment disclosed but is capable of numerous modifications without departing from the scope of the invention as set out in the following claims.