the mechanical components comprising preferred embodiments of an exemplary dispenser 10 will first be described . referring first to fig1 - 3 , dispenser 10 preferably includes housing 11 and removable front cover 13 . in the embodiment , dispenser 10 is configured for mounting on a vertical wall surface ( not shown ) permitting a user to easily access dispenser 10 . housing and cover 11 , 13 may be made of any suitable material or materials such as formed sheet metal , plastic and the like . frame 15 is mounted within housing 11 as shown in fig2 - 3 . frame 15 may be a unitary part made of plastic or other suitable material and secured with respect to housing 11 in any suitable manner . frame 15 supports drive roller 17 , springs 19 , 21 and diverter 23 . drive roller 17 may also be referred to by some in the industry as a “ drum .” preferably , dispenser 10 is adapted to dispense sheet material in the form of a sheet material roll ( not shown ). as is well known , sheet material in roll form comprises a hollow cylindrically - shaped tubular core ( not shown ) and sheet material in the form of a web 25 of sheet material ( fig1 - 15 ) wrapped around the core . the core is typically a hollow tube made of cardboard , plastic or the like . the dispenser shown can accommodate a stub roll ( not shown ) and a reserve roll ( not shown ) of the sheet material . the stub roll may be supported within frame 15 on stub roll holders 27 , 29 mounted on frame 15 . each end of the tubular core of the stub roll is mounted on a respective roll holder 27 , 29 with the respective roll holder inserted into the hollow core . holders 27 , 29 are preferably made of a resilient material so that they may be spread apart to receive the stub roll between them . the stub roll is free to rotate when mounted on holders 27 , 29 . the reserve roll is supported by support arms 31 , 33 and web roll support cups 35 , 37 mounted on respective arms 31 , 33 . each end of the tubular core of the reserve roll is mounted on a respective cup 35 , 37 with the respective cup inserted into the hollow core . arms 31 , 33 are preferably made of a resilient material so that they may be spread apart to receive the reserve roll core between them . as will be appreciated , any type of support structure may be utilized to support the stub and reserve rolls . for example , the stub roll may simply rest on bottom wall 39 of frame 15 without holders 27 , 29 . by way of further example , holders 27 , 29 and support arms and cups 31 , 33 , 35 , 37 could be replaced with a rod inserted through the hollow roll core . such a rod may be supported at its ends by housing 11 . there is no particular requirement with respect to the number of sheet material sources which may be dispensed from dispenser 10 . dispenser 10 could dispense , for example , from single or plural rolls of material depending on the intended use of dispenser 10 . a drive mechanism 41 is provided for discharging web 25 from dispenser 10 . drive mechanism 41 comprises drive roller 17 , tension roller 43 , tension springs 19 , 21 , diverter 23 and the related components as hereinafter described and as shown particularly in fig2 - 15 . preferred drive roller 17 may be a drum - shaped member which is generally - cylindrical in appearance . drive roller 17 may comprise first and second sections 45 , 47 , first and second ends 49 , 51 and outer surface 53 . sections 45 , 47 may be made of plastic or any other suitable material and may be joined by use of adhesives or fasteners 55 ( fig6 ). drive roller 17 is preferably mounted on frame 15 along axis 56 . drive roller 17 is preferably mounted for bidirectional rotatable movement by stub shafts 57 , 59 which extend axially outward from a respective drive roller end 49 , 51 . stub shafts 57 , 59 are received in a respective bearing 61 , 63 . bearing 61 is seated in opening 65 of cam 67 and bearing 63 is seated in opening 68 of frame 15 . bearings 61 , 63 are preferably made of nylon or a similar low - friction material . referring to fig3 - 4 , 6 , and 10 - 15 , eccentric arm 69 is seated on stub shaft 57 and is secured to stub shaft by fastener 71 . arm 69 co - rotates with drive roller 17 . a spring - attachment member 73 is rotatably mounted to end 75 of arm 69 by fastener 77 . member 73 includes arms 79 , 81 for attachment to a respective spring 19 , 21 as described herein . referring to fig1 - 2 and 5 - 6 , a hand wheel 83 linked to drive roller 17 may optionally be provided . hand wheel 83 is provided to permit manual rotation of drive roller 17 , such as to feed web 25 out from dispenser 10 through discharge opening 85 at the time web 25 is loaded into dispenser 10 . hand wheel 83 is linked to drive roller 17 at end 51 by means of a hand wheel post 87 keyed to fit into corresponding female opening ( not shown ) in stub shaft 59 and secured by fastener 89 . as shown in fig2 - 8 , drive roller outer surface 53 preferably includes one or more friction surfaces 91 for engaging and gripping web 25 . friction surfaces 91 are provided to ensure that the drive roller outer surface 53 has sufficient frictional contact with the web 25 so that drive roller 17 will rotate as web 25 positioned across drive roller 17 is pulled from dispenser 10 by a user . the plural friction surfaces 91 ( fig2 - 6 ) may be in the form of sheet - like strips adhered to drive roller outer surface 53 with a suitable adhesive ( not shown ). however , such friction surfaces 91 could be provided in other manners , such as by forming such friction surfaces directly in outer surface 53 . further , the friction surfaces 91 need not be limited to the plural strip - like material shown and could comprise any appropriate configuration , such as a single sheet of material ( not shown ). friction surfaces 91 may consist of any suitable high - friction material , such as grit or rubberized material . an over molded thermoplastic elastomer may also be applied to drive roller 17 out surface 53 . such an elastomer is applied directly to the surface 53 and sets to form a gripping surface similar to friction surfaces 91 . fingers 92 of guard 94 extend into corresponding annular grooves 96 in drive roller 17 to separate web 25 from drive roller 17 so that web 25 does not become adhered to the drive roller 17 ( such as by static electricity ) and to ensure that web 25 is properly directed out of dispenser 10 through discharge opening 85 . guard 94 may be attached across frame 15 by any suitable means well known in the art . drive roller 17 preferably further includes a longitudinal opening 93 through which a cutting blade 95 of a cutting mechanism 97 extends to perforate the web 25 as hereinafter described . tension roller 43 urges web 25 against outer surface 53 of drive roller 17 . tension roller 43 preferably is a generally cylindrically - shaped member having first and second axial stub ends 101 , 103 . roller axial stub ends 101 , 103 fit rotatably in respective slots 109 , 111 provided in frame 15 . as shown in fig3 - 6 , torsion springs 113 , 115 urge tension roller 43 against drive roller 17 . tension roller 43 is generally coextensive with drive roller 17 and is mounted along an axis 117 parallel to axis 56 . tension roller 43 may be provided with annular gripping surfaces 119 seated in a respective annular seat 121 and positioned to abut a respective drive roller friction surface 91 . such gripping surfaces 119 are preferably made of a tactile material such as rubber , or the like . drive roller 17 and tension roller 43 form a nip 123 at the interface of drive roller 17 and tension roller 43 . web material 25 is drawn from a respective stub or reserve roll through nip 123 , against outer surface 53 of drive roller 17 and out of dispenser via discharge opening 85 as described in detail below . drive mechanism 41 further includes springs 19 , 21 and diverter 23 . each spring 19 , 21 is preferably a tension spring . each spring 19 , 21 may be identical to each other , but this is not required . springs 19 , 21 are loaded , or energized , by rotation of drive roller 17 resulting from user web pulling . loaded springs 19 , 21 then power further rotation of drive roller 17 and operation of the cutting mechanism 97 ( as the springs are unloaded ) to complete a dispense cycle . as is well illustrated in fig3 - 5 , 6 , 10 , 10 a - 10 c and 11 - 15 , spring 19 has ends 127 , 129 . end 127 is secured to frame 15 at post 131 and may be secured to post 131 by fastener 133 . the other spring 19 end 129 is attached to arm 79 of spring - attachment member 73 . spring 21 had ends 135 , 137 . spring end 135 is secured to frame 15 at post 139 and may be secured to post 139 by fastener 141 . the second spring 21 end 137 is attached to arm 81 of spring - attachment member 73 . referring further to fig3 - 5 , 6 , 10 , 10 a - 10 c and 11 - 15 , diverter 23 is provided to contact spring 21 and to bend spring 21 when spring 21 is in the rest position of fig1 . preferably , diverter 23 contacts spring 21 between ends 135 , 137 . diverter 23 is secured to frame 15 by adhesive or other suitable fastener 181 ( fig1 b ). referring again to fig1 , 10 a - 10 c and 11 - 15 , diverter 23 may include a guide surface 143 . guide surface 143 preferably includes a groove , or recess , in which spring 21 is fully or partially seated when in the rest position of fig1 . guide surface 143 groove serves as a guide to keep spring 21 in place during the dispense cycle . diverter 23 may be made of materials such as plastics . diverter 23 could be an integral component of frame 15 . in the preferred rest position of fig1 , spring 19 has a generally axial orientation which is retained generally throughout a dispense cycle . spring 21 has a generally axial segment 145 between end 135 and diverter 23 and a generally axial segment 147 between diverter 23 and end 137 . axes 146 , 148 are shown on fig1 b . spring 21 has a segment 149 therebetween which is bent as it contacts diverter 23 . segments 145 , 147 are axial only in the sense that they represent generally straight spring portions about diverter 23 when at rest as in fig1 . put another way , spring 21 is bent by the diverter . the bend preferably includes a radius as shown in fig4 a , 10 b and 10 - 15 . the position and orientation of segment 147 , in particular , will change as spring 21 bends and is moved during a dispense cycle as is well - illustrated in fig1 - 15 . thus , diverter 23 acts on spring 21 such that segments 145 , 147 are not co - axial when in the rest position of fig1 . it is preferred but not required that springs 19 , 21 are essentially co - planar along plane 146 . by way of further example , spring 21 segment 147 could be arranged such that it lies outside of plane 146 in which springs 19 , 21 are arranged ( fig1 ). diverter 23 advantageously permits use of a spring 21 which may be identical to spring 19 , particularly in length and spring force . and , diverter 23 enables this result in a housing 11 which is more compact than if diverter 23 were not present . more specifically , if diverter 23 were not present , it would be necessary to use a spring which would be relatively shorter than spring 21 with the spring end 135 secured to frame 15 at a location proximate the point where diverter 23 contacts spring 21 in fig1 . such a point is identified by reference number 163 in fig1 . it is desirable , however , that the spring selected for use as spring 21 is a relatively longer spring because the relative extension of such a longer spring is less than that of a relatively shorter spring . as a result , the spring rate of the longer spring is more moderate and consistent throughout the full range of spring movement than that of a relatively shorter spring having a relatively more rapid rebound and more powerful spring force . use of a relatively longer spring 21 , therefore , desirably provides for more consistent and smooth operation of drive roller 17 . a relatively shorter spring may be more likely to fail because of the tensile forces applied to it thereby requiring the use of more costly high tensile springs . use of a relatively longer spring provides the manufacturer with the option to use springs made with less costly materials thereby minimizing cost while extending service life of the dispenser . while a relatively longer spring 21 could be used in dispenser 10 without a diverter 23 , such spring 21 end 135 would be required to be mounted below bottom wall 39 of frame 15 ( at approximately point 164 ) to power rotational displacement of drive roller 17 in the same manner as shown in fig1 - 15 . a larger housing 11 would be required to accommodate this mounting location and such a larger housing 11 may be unacceptable for some applications where space is at a premium or a more compact housing 11 and dispenser 10 appearance is desired . referring to fig2 - 15 , a preferred cutting mechanism 97 for cutting web 25 is illustrated . the cutting mechanism 97 is preferably provided to cut fully through web 25 positioned against drive roller 17 outer surface 53 as drive roller 17 rotates under the force applied by user web pulling and springs 19 , 21 . the exemplary cutting mechanism 97 comprises blade 95 , blade carrier 151 , arm 162 , follower 165 , cam 67 and the related components . as shown in fig6 - 8 , blade 95 may be provided with serrated teeth 150 secured to blade carrier 151 by fasteners 153 . blade carrier 151 is pivotally mounted to respective ends 49 , 51 of drive roller section 45 by means of pin 155 seated in bearing 157 and stub shaft 159 seated in bearing 161 . bearings 157 , 161 are seated in respective drive roller ends 49 , 51 . pivoting action of carrier 151 enables blade 95 to extend outward from drive roller 17 to cut web 25 and further enables blade 95 to retract inward to drive roller 17 following cutting . in the embodiment , serrated teeth 150 cut completely through web 25 so that a single sheet 179 of web 25 is provided during user web pulling . arm 69 is attached at one end to blade carrier 151 and supports rotatable cam follower 165 at its other end . arm 69 and cam follower 165 are positioned for mounting outside of first drive roller section 45 end 49 so that cam follower 165 may be positioned in cam track 167 of stationary cam 67 as is well shown in fig9 and 10 - 15 . fig6 and 10 - 15 illustrate exemplary cam 67 . cam 67 is preferably mounted to frame 15 with fasteners 168 so that cam track 167 extends through frame opening 170 and faces drive roller 17 and cam follower 165 . cam track 167 provided in cam 67 includes inwardly arcuate portion 169 and outwardly arcuate portion 171 . cam follower 165 follows cam track 167 as the drive roller 17 rotates during a dispense cycle . cam track 167 is eccentric relative to stub shaft 57 and axis 56 and is structured and arranged such that the action of cam track 167 on cam follower 165 and arm 162 , urges carrier 151 to pivot such that blade 95 extends to cut web 25 and retracts during each revolution of drive roller 17 as described more fully below . tail 172 of web 25 of the reserve roll may be manually loaded into nip 123 when the stub roll is fully depleted . alternatively , an automatic transfer mechanism may be incorporated into dispenser 10 to automatically transfer tail 172 of web 25 of reserve roll to the nip 123 when the stub roll is fully depleted or very near full depletion ., such an automatic transfer mechanism is the subject of commonly owned u . s . pat . no . 6 , 460 , 798 , the entire contents of which are incorporated herein by reference . to provide a frame of reference for location of transfer mechanism , a transfer arm 173 as described in u . s . pat . no . 6 , 460 , 798 and which urges web 25 of reserve roll into nip 123 is shown in fig2 - 6 . other transfer mechanism structure is not shown . operation of exemplary dispenser 10 will now be described particularly with respect to fig1 - 15 . it will be understood that fig1 - 15 illustrate representative positions of drive roller 17 and other dispenser 10 components during a dispense cycle . the operational description will center on drive mechanism 41 and cutting mechanism 97 . web 25 may be supplied by a single roll , a stub roll or a reserve roll . the reader is again referred to u . s . pat . no . 6 , 460 , 798 , incorporated herein by reference , for a description of the structure and operation of exemplary transfer mechanisms suitable for use in supplying web 25 to nip 123 upon depletion of the stub roll . fig1 represents dispenser 10 in a rest , or ready , position prior to commencement of a dispense cycle . web 25 is positioned between drive roller 17 and tension roller 43 through nip 123 . ( tension roller 43 is not shown in fig1 - 15 .) to facilitate threading of web 25 into nip 123 during loading of web 25 , drive roller 17 may be manually rotated in the direction of arrow 175 ( i . e . counterclockwise in the example shown ) by means of hand wheel 83 . as drive roller 17 is rotated , friction surfaces 91 engage web 25 which is urged against such friction surfaces by tension roller 43 and , potentially , by the action of user web pulling . web 25 is drawn through nip 123 as drive roller 17 rotates in the direction of arrow 175 and tension roller 43 rotates in the opposite direction . after exiting nip 123 , web 25 is guided toward discharge opening 84 by arcuate guide wall 177 . web 25 is positioned over a portion of drive roller 17 outer surface 53 friction surfaces 91 . pulling of web 25 by a user draws web 25 tightly across the portion of friction surfaces 91 , as shown in fig1 - 15 . guard 94 fingers 92 extend into corresponding annular grooves 96 of drive roller 17 to separate web 25 from drive roller 17 to facilitate movement of web 25 out of dispenser 10 through discharge opening 85 . web tail 172 is then extended from discharge opening 85 by rotation of hand wheel 83 to an appropriate length for gripping by a user . web 25 is now positioned for dispensing from dispenser 10 . in the rest , or ready , position of fig1 , springs 19 , 21 are partially loaded , or energized , and springs 19 , 21 bias drive roller 17 and arm 69 to the position shown in fig1 . at the beginning of a dispense cycle , blade 95 is preferably retracted within drive roller 17 also as shown in fig1 . dispenser 10 is now ready for use . fig1 represents dispenser 10 shortly after commencement of a dispense cycle . the dispense cycle is initiated by user web pulling of web 25 tail 172 . the tension , or pulling , force of web 25 against drive roller 17 outer surface 53 friction surfaces 91 causes drive roller 17 to rotate in the direction of arrow 175 . springs 19 , 21 are partially extended and are loaded ( i . e ., energized ) as drive roller 17 rotates under the influence of web 25 . fig1 represents a further position of dispenser 10 after commencement of a dispense cycle . spring 19 is near fully extended and loaded ( i . e ., energized ) at a centered position . spring 21 is further partially extended and is being loaded ( i . e ., energized ) as drive roller 17 rotates further under the influence of web 25 . blade 95 begins to move toward web 25 to perforate web 25 as cam 67 cam track 167 urges follower 165 and arm 162 to pivot blade carrier 151 . fig1 represents yet a further position of dispenser 10 after commencement of a dispense cycle . spring 19 is past the near centered position of fig1 and powers rotation of drive roller 17 as the spring is unloaded by release of stored energy . spring 21 segment 147 is now in approximately a centered position and spring 21 is fully loaded ( i . e ., energized ) as shown . spring 21 is just starting to power drive roller 17 rotation at this point in the dispense cycle . blade 95 moves further toward web 25 to perforate the web as cam 67 cam track 167 urges follower 165 and arm 162 to pivot blade carrier 151 . spring 19 provides energy required to extend blade 95 . fig1 represents yet another position of dispenser 10 after commencement of a dispense cycle . springs 19 , 21 are both past their centered positions and combine to power rotation of drive roller 17 as the springs are unloaded and stored energy is released . blade 95 moves fully toward web 25 to completely cut web 25 as follower 165 enters inward portion 169 of cam track 167 . springs 19 , 21 provide energy required to fully extend blade 95 to completely cut web 25 . the result is a single sheet 179 of web 25 being provided to the user . fig1 illustrates a further position of dispenser 10 near completion of a dispense cycle . springs 19 , 21 are both past their centered positions and combine to power rotation of drive roller 17 as stored energy is released . blade 95 begins to retract as follower 165 exits inward portion 169 of cam track 167 . spring 21 is the primary provider of energy required to retract blade 95 and return drive roller 17 to the resting position following web 25 cutting . finally , drive roller 17 is returned to the rest , or ready , position of fig1 . tail 172 of web 25 is extended from discharge opening 85 and is ready to be grasped and pulled by a user . the dispenser 10 is now ready to initiate a new dispense cycle . dispenser 10 and its component parts may be made of any suitable material or combination of materials as stated above . selection of the materials will be made based on many factors including , for example , specific purchaser requirements , price , aesthetics , the intended use of the dispenser and the environment in which the dispenser will be used . while the principles of this invention have been described in connection with specific embodiments , it should be understood clearly that these descriptions are made only by way of example and are not intended to limit the scope of the invention .
apparatus and methods for dispensing sheet material from a sheet material dispenser are described . a drive mechanism powered at least in part by one or more springs discharges sheet material from the dispenser . a diverter redirects at least one of the springs enabling use of a relatively longer spring in a more compact and space - efficient dispenser housing . the dispenser may include a cutting mechanism powered at least in part by the one or more springs .