Abstract:
A cutting machine which dispenses and cuts sheet material includes a carriage on rails for movement parallel to the horizontal rolls carried on a vertical carrousel. The carriage supports a cutting table top and a drive roller at one side for driving the roll of floor covering material on the carrousel in forward direction for feeding the sheet to the table top and in reverse direction for re-winding. A measuring wheel and electric eye for detecting the presence of the material are located on the table top. A sensor is provided to detect if the measuring wheel is de-activated during use. A control unit includes a printer and is arranged to cause measurement and feeding of a measured length of the material which is fed to a re-roller on the carriage. When the measured amount is supplied the printer is operated to print a label defining the material and the length but only if the measuring device remained properly active during the measuring process to ensure the length is accurate and not distorted by error or deliberately.

Description:
The present invention relates to improvements to cutting apparatus for cutting sheet materials, particularly but not exclusively of the type for use with a rolled supply of floor covering material. 
     BACKGROUND 
     Devices used for cutting carpet, vinyl flooring, and other floor covering materials are known. These devices can be as simple as a rack for supporting a roll of floor covering material adjacent a cutting surface such as a floor or table top or may be complex machines. In the simple case where a rack and cutting surface are used the floor covering material is dispensed from the rack onto a cutting surface where it is cut by an individual with a knife. After cutting the floor covering material is manually re-rolled. One disadvantage of this method is that large areas are required to lay out the floor covering material during cutting. A second disadvantage is that if the floor covering material is cut on a floor the floor covering material can be damaged by contact with materials on the floor. 
     More complex apparatus for performing this task are also known. One example is shown in U.S. Pat. No. 4,809,921 issued Mar. 4 th  1889 of Willie Dueck who is the father of the present inventor. This includes a cradle or rack for supporting the roll of floor covering material to be dispensed, a table top across which the floor covering material is drawn, and a cradle for automatically re-rolling the floor covering material. These components are generally mounted on a frame to keep them raised above the floor at an appropriate height for working. A knife blade arranged for travelling across the table top is usually employed to cut the floor covering material. The knife blade is usually mounted at a fixed angle to the table and moves along a slot running laterally across the table through which the knife blade projects. 
     Also in U.S. Pat. No. 5,944,279 issued Aug. 31 st  1999 to the present inventor is disclosed an improved cutter of this general type where the sheet material is guided and controlled by electric “eyes” which detect the position of the edges of the material. These can primarily be used to calibrate the measuring roller to ensure greater accuracy in the measurement. 
     SUMMARY 
     It is one object of the present invention to provide a yet further improved cutter for rolled material such as floor covering material. 
     According to the present invention there is provided an apparatus for cutting a length of sheet material from a supply of the sheet material comprising: 
     a carriage; 
     an unrolling device on the carriage for unrolling a supply roll of the sheet material, the unrolling device being driven such that a front edge of the roll is supplied from the roll; 
     a table surface on the carriage for receiving the sheet from the unrolling cradle such that the sheet passes longitudinally across the table when fed from the unrolling device; 
     a sheet driving roller on the carriage for driving the sheet from the unrolling device across the table; 
     a metering wheel on the carriage arranged to roll on the sheet as it passes from the unrolling cradle and across the table surface for measuring a length of the sheet supplied from the unrolling device; 
     a de-activation detector responsive to de-activation of the metering wheel; 
     a cutting knife mounted at the table surface and movable transversely across the table surface to slit the sheet at a position along the sheet to form a cut portion of the sheet having a required length; 
     a re-rolling cradle on the carriage for receiving the front edge and the cut portion and driven to roll the cut portion from the front edge into a roll for supply of the cut portion; 
     a material detector mounted in a path of movement of the sheet material from the unrolling device to the re-rolling cradle for detecting passage of a front edge of the sheet material and the presence of the sheet material; 
     a printer for printing a label recording a length of the sheet material as measured by the metering wheel; 
     and a control unit responsive to the detection of the front edge by the material detector to commence measuring of the length by the metering wheel to provide a measured length of the material; 
     the control unit being responsive to the de-activation sensor and arranged to prevent printing of a label recording the length in the event that the de-activation sensor detects a de-activation during measuring of the length. 
     Preferably the material detector comprises an electric eye. 
     Preferably the material detector is mounted at the table. 
     Preferably the material detectors is mounted upstream of and adjacent to the cutting knife. 
     Preferably the metering wheel is mounted closely adjacent to the cutting knife. 
     Preferably the metering wheel is mounted immediately prior to the cutting knife. 
     Preferably the metering wheel is mounted so as to contact one surface of the sheet and there is provided a second contacting wheel mounted to contact an opposed surface of the sheet. 
     Preferably the de-activation sensor is arranged to detect separation of the metering wheel and the contacting wheel. 
     Preferably the contacting wheel is mounted on a lever above the table and is movable on the lever to separate the contacting wheel and the measuring wheel. 
     Preferably the de-activation sensor and the material sensor are mounted on the lever. 
     Preferably the printer is arranged to generate a machine readable bar code containing information defining the sheet material and the length. 
     Preferably the control unit is arranged to drive the unrolling device and the sheet driving roller to a predetermined length as measure by the measuring wheel. 
     Preferably the control unit is arranged to slow a speed of drive of the unrolling device and the sheet driving roller as the length is approached. 
     Preferably the carriage is arranged to be located adjacent a horizontal roll of the sheet material carried on a carrousel and wherein the unrolling device comprises an elongate horizontal drive roller extending along the roll parallel to an axis of the roll and movable into contact with the roll while the roll remains on the carrousel. 
     Preferably the carriage is mounted on rails for movement in a direction parallel to the axis of the roll. 
     Preferably the rive roller is arranged to be driven by the control unit in a reverse direction for re-rolling the sheet material onto the roll on the carrousel. 
     According to a second aspect of the invention there is provided an apparatus for cutting a length of sheet material from a supply of the sheet material comprising: 
     a carriage; 
     an unrolling device on the carriage for unrolling a supply roll of the sheet material, the unrolling device being driven such that a front edge of the roll is supplied from the roll; 
     a table surface on the carriage for receiving the sheet from the unrolling cradle such that the sheet passes longitudinally across the table when fed from the unrolling device; 
     a sheet driving roller on the carriage for driving the sheet from the unrolling device across the table; 
     a metering wheel on the carriage arranged to roll on the sheet as it passes from the unrolling cradle and across the table surface for measuring a length of the sheet supplied from the unrolling device; 
     a de-activation detector responsive to de-activation of the metering wheel; 
     a cutting knife mounted at the table surface and movable transversely across the table surface to slit the sheet at a position along the sheet to form a cut portion of the sheet having a required length; 
     a re-rolling cradle on the carriage for receiving the front edge and the cut portion and driven to roll the cut portion from the front edge into a roll for supply of the cut portion; 
     a material detector mounted in a path of movement of the sheet material from the unrolling device to the re-rolling cradle for detecting passage of a front edge of the sheet material and the presence of the sheet material; 
     and a control unit for driving the unrolling device and the sheet driving roller; 
     wherein the carriage is arranged to be located adjacent a horizontal roll of the sheet material carried on a carrousel and wherein the unrolling device comprises an elongate horizontal drive roller extending along the roll parallel to an axis of the roll and movable into contact with the roll while the roll remains on the carrousel. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings, which illustrate an exemplary embodiment of the present invention: 
     FIG. 1 is a vertical cross sectional view through a cutter for sheet material according to the present invention showing the cutter in association with a roll of the sheet material carried on a separate carousel. 
     FIG. 2 is a top plan view of the cutter of FIG.  1 . 
     FIG. 3 is a cross sectional view of a portion only of the cutter of FIG. 1 showing the construction of the metering system. 
    
    
     DETAILED DESCRIPTION 
     Reference is made to the above patents which show the construction of a cutter and provides many of the details of the device which are used in the machine as described herein. Thus the details previously described are omitted from the present application since these are available to one skilled in the art from the above patents. 
     The cutter is indicated generally at  10  and is arranged for co-operation with a carousel  11  of a conventional nature. The carousel is of the type which supports rolls of the sheet material on a chain  12  so that the rolls  13  are held with horizontal axes generally parallel at spaced positions around the chain  12 . The chain  12  is thus driven around top and bottom chain wheels so that the rolls  13  are moved to the required position on the carousel spaced above the ground and at the front of the carousel for co-operation with the cutter  10 . Carousels of this type are of course well known and commercially available. 
     The cutter therefore provides in general a drive system which transports a front edge  14  of the sheet material on the roll  13  across the cutter to a re-rolling cradle  15  again of a conventional nature described in the above patents. 
     The cutter  10  comprises a frame  16  which carries the drive elements together with a cutter knife  17  and a metering system  18 . The frame  16  is mounted on a sub frame  19  which carries the frame  16  and allows movement of the frame  16  in a direction towards and away from the rolls  13  on rollers  20  provided between the frame  16  and the sub frame  19 . Thus the frame  16  can be pulled away from the carousel by rolling relative to the sub frame  19  to allow the carousel to rotate freely without interfering with the cutter. The frame  16  can then be moved manually or driven by suitable propulsion systems to a position at the roll  13  where the drive system of a cutter engages the roll for driving rotation of the roll for feeding and returning the sheet material relative to the roll  13 . 
     The sub frame  19  is carried on wheels  21  which roll on rails  22  carried on the ground  23 . Thus the sub frame  19  can be moved along in a direction generally parallel to the axes or rolls  13  from one carousel to a next adjacent carousel. The rails  22  hold the sub frame in position along side the carousel so that forces from the frame  16  pushing the drive mechanism against the roll  13  are communicated back to the sub frame  19  and the rails  22  to hold the frame  16  in fixed position and square relative to the axis of the roll. 
     The frame  16  defines a table top  23  over which the sheet material from the roll  13  is passed as it passes the metering system  18  and the cutter  17  on its way to the re-rolling system  15 . The table top  23  includes a slot  24  for co-operation with the cutter blades of the cutter  17  with a cutter  17  being carried on rollers  25  which pass over the sheet material in the cutting action. The slot  24  is arranged transverse to the table top so that the cutter is operated only to cut across the width of the sheet material when a length of the sheet material has been measured to the required length ready for cutting to the required length and rolling into the re-rolling system  15 . 
     The construction of the cutter is shown in the above patents and alternative arrangements for the cutter can be used. The drive system for the cutter is not shown herein since it is then available to one skilled in the art from the above patents. 
     The drive system includes main drive rollers  26  and  27  which engage the sheet material on the roll  13  for driving rotation of the roll  13 . One or both of the rollers  26  and  27  may be driven. One of the rollers is mounted above the other so that the rollers can cradle a portion of the surface of the cylindrical roll of the material. The rollers are carried at a fixed position on an inclined section  16 A of the frame so that the lower part  16 B of the frame can pass underneath the bottom part of the roll leaving the roller  26  and  27  to engage the roll at approximately the 7 and 9 o&#39;clock positions around the axis of the roll. 
     At the front of the table top is provided a further drive roller  29  which acts to carry the strip material onto the table top so that it is transported across the table top by its momentum to a further drive roller  30  at the far end of the table top  23 . 
     On the table top  23  is provided the metering system  18  which is shown in more detail in FIG.  3 . This comprises a support post  181  attached to the table top  23  and standing upwardly therefrom. A pivot arm  182  extends across the table top generally parallel to the table top and carries a top contact wheel  183  of the metering system. The arm  182  is biased into a lowered position in which the contact wheel  183  presses downwardly against the bottom metering roller  184  located at the table top  23  with an upper part of the roll  184  projecting through the table top for contacting a sheet material as it passes over the table top. Thus the sheet material is squeezed between the contact roller  183  and the metering roller  184  and as it passes through the nip formed therebetween causes rotation of the rollers  183  and  184  thus providing a metering action dependent upon the number of turns of rotation of the metering roll. 
     In the embodiment shown the bottom roller  184  is the metering roll and the top roller is merely a contact or pressure roller. However both rollers may act as metering rollers or the upper roller  183  may act as a metering roller with the lower roller acting merely as a contact or pressure roller against the material to form a nip. 
     The arm  182  carries a handle  185  by which the arm  182  and the roller  183  can be manually lifted by a pivotal action of the arm relative to the post  181  thus releasing the roller from its nipping position. 
     The arm  182  carries a transmitter portion  186  of an electric eye  187  with the beam passing through the table top at an opening  188  immediately upstream of the slot  24  and immediately downstream of the metering rollers. The arm  182  includes a detector schematically indicated at  89  which detects the proper positioning of the pressure roller  183  during the metering action. Thus the intention is that the metering action is monitored at all times to ensure that it is being completed and carried out effectively as the material passes through the nip between the rollers. In the event that a user, in error or deliberately, raises the roller so as to prevent the proper metering action from occurring during feeding of the sheet material then this will be detected by the sensor  189 . It will be appreciated that the intention is that the length of material passing through the metering system is properly measured and cannot be changed by the user to add improperly more material than is preset to be fed. 
     The frame  16  further carries a control unit  35  which operates to control a label printer  36  and to control a drive mechanism  37  acting to drive the various components of the system. The control unit co-operates with a manually operable key pad  38  by which information can be input into the control unit by the operator. 
     In operation the frame  16  is moved into position alongside a selected one of the rolls  13  by movement along the rails and by movement transverse to the frame  19  so as to press the drive system against the roll  13  for feeding the selected sheet material onto the cutter. 
     The drive system is then operated by the control unit  35  through the drive  37  to drive the end  14  of the sheet material onto the cutter and across the table  23 . 
     During this movement the electric eye  187  communicates to the control unit  35  that there is no sheet material in place on the table top. As soon as the sheet material reaches the electric eye and covers the hole  188 , the presence of the sheet material is detected by the electric eye and communicated to the control unit to halt the drive system. The hole  188  is located between the metering rolls and the slot  24  of the cutter and the metering rolls are positioned as close to the cutter as possible so that the spacing therebetween is minimal. Thus the front edge of the sheet material is halted substantially at the cutting slot  24  immediately after it covers the hole  188  which is located immediately adjacent the slot  24 . 
     This movement therefore sets up an initial position for the cutting action so that the sheet material is in position ready to be fed and re-rolled. 
     The user enters into the keypad a required length for the sheet material to be cut and the code information relating to the sheet material on the roll  13 . 
     The metering system is moved to the activated position with the pressure roller  183  forming a nip with the metering roller and the sensor  189  detects that the metering system is properly in position. 
     With the system thus set up in the initiated condition, the operator activates the control unit through the operating pad  38  so as to start the forwarding movement of the sheet material through the metering system and into the re-roll cradle  15 . The control unit acts to drive the drive system through the required length as measured by the metering system until the preset length required is close to complete whereupon the drive  37  is controlled to slow the driving movement of the driving rollers so that the sheet material moves toward completing the required length at a slower rate than the normal drive rate to prevent overshooting and to reduce momentum in the system when stopping the feeding movement of the sheet material. 
     Thus when the required length is completed through the metering system, the location of the end of the required length is positioned at the cutter slot  24  and the system is halted. 
     In the event that the detector  189  provides an indication that the metering system has been deactivated any time during this feeding motion, this is communicated as an error signal to the control unit which then invalidates the measuring of that length of material. In the event that an invalid measuring has occurred, the drive system is activated in reverse and particularly the roller  26  or  27  is driven in reverse so as to rewind the material back onto the rolls  13  for another measuring action. 
     In the event that the measuring is completed effectively and there has been no indication of deactivation of the measuring system by the sensor  189 , the control unit  35  is activated to print a label L which carries a bar code B. The printer is generally of a conventional nature for printing information relating to the particular roll  13  selected and the length of material measured from that roll. Thus the control unit can be controlled to simply printout in human readable form and in machine readable form the material concerned and the length concerned or it can be controlled to generate further information such as a total price. In most practical examples, the user will enter into the keypad  38  a code identifying the material on the rolls  13  and the length required and these items are then printed onto the label in human readable and machine readable form for communication to the checkout for the customer taking the rolled sheet material for purchase. 
     When the transaction is completed and the rolled sheet material from the cradle  15  removed, the drive system again can be operated in reverse so as to rewind the material back onto the roll  13  and the frame moved to its initial storage position spaced from the carousel for commencement of a new cycle. 
     Instead of moving the whole carriage, one of the rollers  26  and  27  may be mounted on a lever which is moved into contact with the roll without necessity of moving the carriage toward the roll. 
     In the example shown, the deactivation system is used to measure or detect movement of the arm  182  which detects separation of the rollers. However other forms of sensing mechanism can be used which are responsive to separation of the rollers  183  and  184  and these will be well known to one skilled in the art. 
     While embodiments of the present invention has been described in the foregoing, it is to be understood that other embodiments are possible within the scope of the invention. The invention is to be considered limited solely by the scope of the appended claims.