Abstract:
A dispenser sequentially dispenses web material from a working web roll and then a reserve web roll. A web sensing mechanism senses the presence of the working web at a back side of the main feed roller and introduces the leading end of the reserve web roll to a feed nip defined by two feed rollers immediately after the trailing end of the working web roll passes over a back side of the feed roller. Web sensing, and controlled introduction of the leading end of the reserve web to the feed nip, are carried out by a simple and effective interaction of a grooved main feed roller, and a pair of pivotable lever arms—a web sensing arm mounted at the backside of the rollers, and a transfer arm mounted at the front side. The mechanism avoids double feeding of web by sensing the presence or absence of web at the back-side of the main feed roller. Transfer fingers of the transfer arm are movable against the reserve roll web and into corresponding grooves in the main feed roller such that a leading end portion of the reserve roll web is reliably moved into the vicinity feed roller nip, where serrations provided in the edges of the grooves facilitate a gripping of the leading end portion to pull the web through the nip. The feed path is arranged to extend away from the transfer fingers so as to avoid interference of the transfer fingers with the subsequent feeding of the web.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to flexible sheet dispensers for sequentially dispensing a web of material from a plurality of rolls, and in particular to an automatic transfer mechanism for transferring the feed supply from a working roll to a reserve roll, upon exhaustion of the working roll. 
     Industrial dispensers for toweling are primarily designed to dispense either a continuous length of web material, folded paper towels, or rolls of paper towels. Continuous towels are generally made of a reusable material and form a towel loop outside of the dispenser cabinet for the consumer to use. Folded towels are paper towels which are pre-cut and folded into various configurations to be individually dispensed for use. Roll towels are continuous rolls of paper toweling which are wound around a cardboard core and which are, upon dispensing, separated into and delivered as individual lengths of material. 
     Continuous web dispensers, such as those disclosed in U.S. Pat. No. 2,930,663 to Weiss and U.S. Pat. No. 3,858,951 to Rasmussen, require the user to pull on the loop of exposed toweling in order to cause a length of clean toweling to be dispensed and the exposed soiled toweling to be correspondingly taken up within the dispenser. Although economical, the continuous exposure of the soiled toweling is deemed unsightly, and therefore unacceptable to many consumers when compared to the many available alternatives. Further, the exposure and possible reuse of soiled toweling may present additional health hazards and sanitation concerns which should be avoided. 
     The use of either interfolded paper towels or C-fold paper towels eliminates the potential health risks associated with continuous web toweling. Dispensers for folded paper towels allow a user to pull the exposed end of a new individual towel in order to dispense the towel. These dispensers, such as the one disclosed in U.S. Pat. No. 3,269,592 to Slye et al., are also easy to refill with folded towels, That is, when the dispenser is partially empty, the cover can simply be removed and the remaining stack of towels can be replenished through the open top. Folded towels are, however, not usually the most economical alternative for institutional or other high-volume situations. 
     Roll towels are cheaper to manufacture than folded towels and also eliminate the potential health and sanitation problems associated with continuous web toweling systems. Dispensers for roll towels usually include a lever, crank, or other user-activated mechanism for dispensing a length of towel and a blade for then severing the length of towel from the remaining roll. In contrast to folded towels, however, there is no way to simply replenish a partially depleted roll of web material in a roll dispenser. In some prior art dispensers, a new roll must be substituted thereby resulting in the waste of the partially depleted roll, or “stub” roll. To overcome the problem of stub roll waste, roll dispensers have been designed to dispense two rolls of web material sequentially such that upon depletion of a primary roll, feeding from a reserve roll is commenced. Prior art systems have accomplished this transfer by either modifying the end of the web material or modifying the roll core upon which the web material is wound, such as the system disclosed in U.S. Pat. No. 3,288,387 to Craven, Jr. Alternatively, the system of U.S. Pat. No. 3,628,743 to Bastian et al. senses the diameter of the primary roll in order to activate the transfer to the reserve roll, and the system of U.S. Pat. No. 3,917,191 to Graham, Jr. et al. senses the tension in the primary roll in order to detect when it is nearly exhausted. Unfortunately, tension responsive transfers are not particularly reliable since conditions other than reaching the end of the roll can trigger their operation, such as the slackening of the web or a break in the web material. Diameter responsive transfers also have a drawback in that the reserve web begins dispensing prior to the complete exhaustion of the primary roll. Thus, for a short time web material is dispensed simultaneously from both rolls and again results in a waste of material. 
     To overcome these disadvantages, the systems of U.S. Pat. No. 4,165,138 to Hedge et al. and U.S. Pat. No. 4,378,912 to Perrin et al. provide a transfer mechanism which is based on the feed rolls themselves. These systems utilize a transfer mechanism which senses the absence or presence of paper around a grooved feed roll by using a sensing finger which rides along the top surface of the web material and which then drops down into the groove in the feed roll when the trailing end of the primary web has passed thereover and thus uncovers the groove. Responsive to the movement of the sensing finger into the groove, the reserve web is introduced into the feed nip between the feed rolls and dispensing from the reserve roll begins. This type of transfer mechanism generally eliminates the false transfer associated with tension responsive systems and reduces the amount of double sheet dispensing which occurs in other prior art diameter and end of roll responsive systems. The use of sensing fingers on the web material, can, depending on the design, produce extra friction which can inadvertently tear the web. Also, the introduction of additional components to sense the absence of the web and transfer the reserve web into the feed nip between the feed rollers creates additional opportunities for a transfer failure or interference with web feed to occur. In particular, in each of the designs of the Hedge et al. and Perrin et al. patents, a tucking device (blade or roll) is used. The device pivots into very close proximity to the feed nip, and remains there through the subsequent dispensing from the reserve roll. It is evident that interference with the web feed from the reserve roll could result if proper positioning of the transfer device, away from the nip, is not maintained. 
     A need has therefore existed for a flexible sheet dispenser having an automatic transfer mechanism which, in addition to substantially eliminating simultaneous dispensing from both primary and reserve rolls, requires few additional parts within the dispenser and which is not prone to interference with the proper dispensing of either the working or reserve roll web material. A transfer mechanism that, to a large extent, fulfills this need is described in commonly assigned U.S. Pat. No. 5,526,973 to Boone et al. Therein, movement and interengagement of one grooved feed roller relative to the other upon depletion of a stub roll, actuates a transfer mechanism that introduces a reserve web into the feed nip. While generally quite effective, the movement and spring biasing of a relatively high mass feed roller can lead to difficulties. The feed roller spring bias force must be within a relatively narrow window. If the spring bias is set too high, the biasing force may inhibit smooth feeding of the web material through the rollers, and result in tearing of the web material. If it is set too low, the mechanism may not actuate effectively to cause a transfer of feed to the reserve roll immediately upon depletion of the stub roll. Over time, the spring bias provided to move one roll relative to the other is prone to eventually decrease, e.g., due to fatigue of the spring, such that ultimately the spring force may fall below the required relatively narrow range and thus be insufficient to properly actuate a web transfer. There thus remains a need for an automatic web transfer mechanism that can provide increased reliability, robustness and cost effectiveness. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, it is a principal object of the present invention to provide a web transfer mechanism for a flexible sheet dispenser having increased reliability, robustness and cost effectiveness. 
     It is a further object of the invention to provide a web transfer mechanism which permits simple set-up/loading of the dispenser for sequential dispensing from a working roll and then a reserve roll. 
     It is another object of the present invention to provide a web transfer mechanism that avoids double feeding of web from the reserve roll and working (stub) roll. 
     A further object of the present invention is to provide a web transfer mechanism which is removed from the web feed path about the feed roll, such that post-transfer interference with web feed from the reserve roll is reliably avoided. 
     These and other objects are achieved, in accordance with a first aspect of the present invention, by a web transfer mechanism for providing, in a flexible sheet material dispenser, automatic transfer of web feed from a working roll to a reserve roll. A pair of feed rollers forms a nip for receiving a leading end of a sheet material web. A first one of the feed rollers includes at least one circumferential groove. A first arm is movably mounted adjacent and to one side of the first feed roller. The first arm includes a web transfer finger. The finger is movable into contact with a leading end portion of a sheet material web from the reserve roll positioned on the one side of the first feed roller, to a transfer position close enough to the first feed roller to move the leading end portion into the vicinity of the nip such that upon driving of the rolls the web is carried through the nip and along a path avoiding subsequent contact of the web with the finger. A second arm is movably mounted adjacent and to a second side of the first feed roller. The second arm includes a web sensing finger biased toward the feed roller into a web-present sensing position wherein the sensing finger rides lightly upon the surface of a sheet material web as it passes around the first feed roller, and such that when no sheet material web is present the sensing finger moves into a no-web-present position within one of the circumferential grooves. A stop arm is movably connected to the second arm. The second arm is capable of assuming a stop position preventing the web transfer finger from moving into the transfer position when the web sensing finger is in the web-present sensing position. The stop arm is movable with the second arm to a release position allowing the web transfer finger to move into the transfer position when the second arm moves into the no-web-present position. 
     A second aspect of the invention is likewise embodied in a web transfer mechanism for providing, in a flexible sheet material dispenser, automatic transfer of web feed from a working roll to a reserve roll. A first one of a pair of feed rollers forming a nip for receiving a leading end of a sheet material web includes at least one circumferential groove with serrations formed in a sidewall thereof A web transfer arm is movably mounted adjacent the first feed roller. The arm is movable into contact with a leading end portion of a sheet material web from the reserve roll, positioned on a side of the first feed roller, to a transfer position close enough to the first feed roller to move the leading end portion into the vicinity of the nip such that upon driving of the feed rollers the web of the reserve roll is gripped by the first feed roller, assisted by the serrations, and carried through the nip. 
     The above and other objects, features and advantages of the present invention will be readily apparent and fully understood from the following detailed description of preferred embodiments, taken in connection with the appended drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of a rolled material dispenser with a housing portion cut-away to reveal, in left end-view, a web feed roller arrangement and associated sub-assembly, including a reserve roll web retaining mechanism in accordance with the invention. 
     FIG. 2 is an enlarged left end view of the web feed roller arrangement and associated sub-assembly shown in FIG.  1 . 
     FIG. 3 is a front elevational view of a shield structure forming part of the sub-assembly seen in FIG. 2, extending along and in close proximity to the main feed roll; associated structure is removed on the right half to show the shield without obstruction. 
     FIG. 4 is an enlarged left end view of the feed roller arrangement seen in FIG. 2, and showing a second sub-assembly (omitted in FIG. 2) of a web sensing and transfer mechanism in accordance with the present invention. 
     FIG. 5 is a partial front side elevation view of a web transfer arm and transfer arm extension forming part of the web sensing and transfer mechanism shown in FIG. 4, illustrating, in addition, an upper pinch roll shortened to provide clearance for engagement of a swinging stop arm and a finger of the transfer arm extension. 
     FIG. 6 is a left end view of a pivotable web sensing arm (and balance arm attached thereto), in accordance with the invention. 
     FIG. 7 is a front elevational view of the pivotable web sensing arm of FIG.  6 . 
     FIG. 8 is a partial top plan view of the left end of the pivotable sensing arm, and attached rearwardly extending balance arm. 
     FIG. 9 is a side elevational view of the swinging stop arm seen in FIG.  4 . 
     FIG. 10 is a front end elevational view of the stop arm shown in FIG.  9 . 
     FIG. 11 is a left end elevational view of the swinging transfer arm shown in FIG. 4, and illustrating more clearly its pivotable mount to the shield. 
     FIG. 12 is a partial front side elevational view of the transfer arm shown in FIG. 11, shown in relation to a side plate of the dispenser chassis, and a dispensed towel. 
     FIG. 13 is a partial top plan view of a grooved main feed roller in accordance with the present invention, with relative positions of related operating components figuratively illustrated. 
     FIG. 14 is an end elevational view of the main feed roll shown in FIG.  11 . 
     FIG. 15 is a partial profile view of a groove-forming wall surface of a main feed roller, illustrating a preferred configuration of edge serrations for facilitating a web transfer in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, the general outline of a conventional-style dispenser cabinet or housing is illustrated. The dispenser housing comprises a five-sided cover member  1  pivotably mounted at pivot point  3  to a shallow tray-like base member  5 . Base member  5  has a back wall  6  provided with appropriate openings (not shown) to accommodate fasteners for attachment of the dispenser to a wall. 
     A reserve roll R of flexible sheet material, such as paper toweling, may be suitably supported between a pair of cantilever mounted wing members  7  extending from the inside of back wall  6 . Each wing member  7  carries a cup  9  at its free end, which enters into the opposite ends of the core of reserve roll R. This mounting of reserve roll R within a dispenser housing is fairly conventional, and thus no further discussion of such structure is required. Additional generally well known features of the dispenser include a pair of side plates  8  (see, e.g., FIGS. 3 and 12) extending along the opposite sides of the dispenser in the lower part thereof. Side plates  8  serve to provide rotatable mounting locations for the feed rollers and other operative components of the dispenser, to be described. 
     The feed rollers include a main feed roller  11 , and upper and lower pinch rolls  13  and  15 . An opening  17  at the lower front portion of dispenser housing  1  provides a dispenser exit, i.e., towel access slot. As shown, the web being dispensed is provided by a stub roll  16  held loosely in a compartment formed by cover  1  below reserve roll R. Extending along and in close proximity to the towel access slot is a reserve roll web (leading end) retaining mechanism  18 . 
     Although not shown nor absolutely required, typically the inventive web transfer mechanism will be implemented in a dispenser including a mechanism for providing motorized or manual web feed control, e.g., a motor or manual crank for driving the feed rollers, and a web cutting mechanism. Such mechanisms are well known in the art. 
     FIG. 2 shows more clearly various operative parts of web retaining mechanism  18  positioned at the front side of main feed roller  11 . A shield  19  extending across the full width of the feed roller is secured by screws (e.g.,  20 ), adhesive or the like, to the rectangular base of a generally conventional stripper bar  22 . Stripper bar  22  has arms  27  serving to strip web from main feed roll  11  upon emerging from the nip formed between main feed roller  11  and lower pinch roll  15 . As shown, the leading end portion  23  of the web from roll R (see FIG. 1) fits into a space between shield  19  and each of a plurality of upstanding web retainer plates  21 . A narrow flat spring  25  is fastened to each of a plurality (e.g., a pair) of stripper bar arms  27  extending into grooves  38  (see FIG. 13) in main feed roller  11 . Springs  25  project through respective openings  29  in shield  19 , to hold the web leading end  23  in place for a subsequent transfer of web end  23  into the nip formed between main feed roller  11  and upper pinch roller  13 . Together, retainer plate  21  and spring  25  constitute a web retainer clip. 
     As seen in FIG. 3, shield  19  has a pair of flanges  31  at each of its lateral ends, on which a gravity-controlled pivotable transfer arm  33  (see FIGS. 4,  5 ,  11  and  12 ) may be hingedly mounted, at a position below and on a front side of main feed roller  11 . Transfer arm  33 , formed primarily as a flat tray-like structure with inwardly directed strength imparting end, bottom and top flanges  34  (see FIGS.  11  and  12 ), carries a plurality (e.g., three) transfer fingers  35  (two seen in FIG. 12) located at, and on either side of, a centerline of arm  33 , in alignment with corresponding feed roller grooves  37  (two seen in FIG.  13 ). For strength, transfer fingers  35  may be formed as integral extensions of flat-sided vertical ribs  36  protruding from an inside face of transfer arm  33 . The flange  34  located between transfer fingers  35  extends inwardly to a greater extent than the other flanges, in order to provide additional stiffening of the fingers. As best seen in FIG. 13, main feed roller  11  has circumferential friction (e.g., rubber) surface elements  12  to grip and move the web, and deep grooves at spaced intervals along its length. Three grooves  37  (placed at and on either side of a center line of roller  11 ) accommodate transfer fingers  35  at the front side of the feed roller. Each groove  37  off-set from centerline groove  37  further accommodates, at the rear side of roller  11 , web sensing fingers, as will be described. A pair of grooves  38  (one shown), adjacent the off-set grooves  37 , are aligned with a corresponding one of web retainer plates  21  on the front side, and receives a stripper bar arm  27  at a lower front side, as best seen in FIG.  2 . At the rear side of main feed roller  11 , grooves  38  accommodate an additional web sensing finger (to be described). 
     Preferably, edges  60  (see FIG. 13) of grooves  37  are serrated or notched to facilitate gripping of web material during a transfer operation. A series of relatively small and shallow diagonally oriented triangular cuts can be provided on opposing groove sidewalls, as shown in FIG.  13 . Alternatively, edges  60 ′ comprising a series of cuts (e.g., ten cuts spaced in 36° angular intervals) extending perpendicular to the rotational axis of the main feed roller and at a slight angle below lines tangent to the roller, as shown in FIG. 15, can provide a greater groove surface area extending generally parallel to the entry direction of the leading end portion of web at the time of transfer. This permits greater contact with the leading web portion, and gripping of the same with increased strength, upon actuation of a transfer operation. 
     As best seen in FIG. 5, on one end of transfer arm  33  (right end as shown), beyond the width of a dispensed towel web and a slightly shortened upper pinch roller  13 , an upwardly directed transfer arm extension  39  includes a stop finger  41  extending inwardly of the dispenser, and a coil spring  43  projecting outwardly. Spring  43  is, when the dispenser cover is fully closed, contacted by an inside surface or projection of the cover. By virtue of the resulting spring bias, spring  43  supplies a slight force serving to pivot transfer fingers  35  forward into main feed roller grooves  37 , but only upon a release of the transfer arm (to be described), in order to transfer retained leading web edge  23  into the feed nip, to thereby initiate dispensing from reserve roll R. Obviously, spring  43  could be appropriately mounted on the inside of the pivotable dispenser cover, instead of on transfer arm extension  39 . Transfer arm extension  39  can be located at either end of transfer arm  33 , but must be arranged in alignment with a swinging stop arm (to be described). 
     Referring now to FIG. 4, in conjunction with FIGS. 6-10, a web sensor arm  45  extends across the full width of the dispenser, at the rear of main feed roller  11 , and is pivotally mounted between dispenser side plates  8 , on pivot axis  46  located above and slightly rearwardly of main feed roller  11 . Stub shafts (not shown) may be provided at each end of arm  45 , to ride in bearings in dispenser side plates  8 . A plurality of sensor fingers  47  (four shown in FIG. 7) are located along the length of arm  45  to fit into corresponding grooves  37 ,  38  (see FIG. 13) of main feed roller  11 . Additional strength is imparted to fingers  47  by a rib  48  extending centrally along the arcuate outer surface of each finger  47 . As seen in FIG. 4, an arcuate back plate  49  having slots (not shown) to accommodate fingers  47  also extends about a rear side of main feed roller  11 , in order to define a path leading the web material around roller  11  and into the second nip formed between main feed roller  11  and lower pinch roller  15  (see FIG.  2 ). 
     Web sensor arm  45  is lightly loaded, preferably by a balance arm  51 , or alternatively by a spring, so that sensor fingers  47  will ride lightly on the surface of a web present at the back side of feed roller  11 , and pivot into the associated feed roller grooves when no web is present. The use of a balance arm is preferred since the biasing force can be maintained constant over time. The ideal balancing torque can be empirically determined for the particular dispenser application. 
     On the right end of sensor arm  45  is a cup-like sensor arm extension  53  (see FIG.  4 ), in alignment with transfer arm extension  39  located on the opposite side of main feed roller  11 . Extension  53  serves to pivotably mount a swinging stop arm  55 , and to predetermine the positions of arm  55  at the limits of its range of its pivotal movement. As best seen in FIG. 4, the pivot axis of stop arm  55  preferably coincides with pivot axis  46  of web sensor arm  45 . Stop arm  55  has a convex end surface arranged to contact an arcuate end surface  44  of stop finger  41  of transfer arm extension  39 , when sheet material webbing is present at the back side of main feed roller  11 . The convex end surface of arm  55  should have a radius of curvature no larger than the radius of the pivot arc of arm  55 . The mating end surfaces of stop arm  55  and stop finger  44  are preferably polished or otherwise made highly smooth. The smooth and arcuate nature of the mating end surfaces reduces friction and thereby facilitates a release-action to be described. 
     Cup-like sensor arm extension  53  has a lower inner surface  57  that positively lifts stop arm  55  for effecting a transfer of web feed. Extension  53  has a sloping upper inner surface  59  that limits upward movement of stop arm  55 , but allows stop arm  55  to pivot sufficiently within the cup to rest, in one stage of the operation (to be described), on top of transfer arm extension finger  41 . This occurs when transfer arm  33  is in a forward, transfer positioned when sensor fingers  47  are located outside of the feed roller grooves, in a web present position. 
     The components of the inventive web transfer mechanism may be manufactured using known materials and manufacturing techniques. For example, durable thermoplastic plastic material, e.g., DELRIN or equivalent, and injection molding, can be used to form stripper bar  22  (and integral arms  27 ), shield  19 , web retainer plates  21 , web transfer arm  33  (and integral extension  39 ), web sensor arm  45  (including integral cup-like extension  53  and fingers  47 ), and swinging stop arm  55 . The feed rollers may comprise molded plastic hubs on circular steel shafts, and separately applied rubber facing surfaces. Various other suitable materials and manufacturing methods will be apparent to those skilled in the art. 
     Sequential operation stages of the above-described inventive web transfer system are now explained. 
     1. Dispenser Empty, Cover Closed 
     Without web material present at its backside, main feed roller  11  has allowed pivoted web sensor arm  45 , loaded by balance arm  51  at the rear, to pivot sensor fingers  47  into corresponding grooves  37 ,  38  provided in main feed roller  11  (see FIG.  13 ). This causes swinging stop arm  55  to be lifted upwardly, as seen in FIG. 4, releasing transfer arm extension  39 , at the front side of main feed roller  11 , to pivot inwardly of the dispenser under the bias of spring  43  contacted by pressure of the closed cover  1 . This causes transfer fingers  35  to pivot into exposed feed roller grooves  37  at the front side of main feed roller  11 . 
     2. Cover Opens 
     As dispenser cover  1  is pivoted downwardly about pivot point  3  to an open position, the spring pressure on transfer arm extension  39  is relieved, allowing transfer arm  33  to drop by gravity to the position shown by the phantom lines in FIG. 11, leaving a clear area in front of main feed roller  11 . The custodian loads a towel roll into reserve roll wing members  7  (see FIG.  1 ), then leads web end  23  down in front of feed roller shield  19 , and into the retainer clips formed by retainer plates  21  and flat springs  25 . 
     3. Cover Closes 
     As cover  1  is closed, it pivots transfer arm  33  upwardly, allowing transfer arm extension arm finger  41  to pass under raised stop arm  55 . By pressure from cover  1  contacting spring  43 , transfer arm  33  is actuated to move transfer fingers  35  into pressing contact with portions of the towel web adjacent retained edge  23 , to thus force the web portions at least partially into feed roller grooves  37 , where serrated edges  60  (or  60 ′) of the grooves (see FIGS. 13 and 15) assist with gripping of the web material on rotation of feed roller  11 . Subsequent power or manual operation of feed roller  11  pulls the towel web out of the retainers, folds leading end portion  23  over, and carries the folded end portion around to the rear of main feed roller  11 . At this point, the web contacts the ends of sensor fingers  47  and lifts the fingers out of the feed roller grooves  37  to ride on the surface of the web. Simultaneously, cup-like sensor arm extension  53  is pivoted downwardly. Swinging stop arm  55  remains on top of transfer arm extension finger  41 , as stop arm  55  pivots freely in the ample clearance provided by the cup-like structure. On the front side of main feed roller  11 , transfer fingers  35  remain in open feed roller grooves  37 ; at the rear, sensor fingers  47  ride on the surface of the towel web, as the sheet material (e.g., towels) is being dispensed. 
     4. Indicator (or transparent window) on Cover Alerts Custodian that Initial Towel Roll has Reduced to Stub-roll Size. Cover Opened. 
     As dispenser cover  1  is pivoted open, transfer arm  33  drops once again, by gravity, to the open position shown in FIG. 11, pivoting transfer arm extension finger  41  out from under swinging stop arm  55 . This permits stop arm  55  to drop to its lowermost, horizontal stop position. A custodian removes the remains of roll R (now a stub roll  16 ) from its support wings  7  and drops it into the bottom compartment (see FIG.  1 ). The web of stub roll  16  remains threaded through the mechanism, as seen in FIG.  1 . The custodian loads a fresh reserve roll R into wing members  7 , threads the leading end portion of the web down in front of main feed roller  11 , and slides the leading web edge into the spring clips formed by retainer plates  21  and flat springs  25 . (The steps of loading a reserve roll are the same as loading the initial roll in previous stage  2 .) 
     5. Cover Closes 
     Closing of cover  1 , following loading of reserve roll R, pivots transfer arm  33  upwardly, but the end of transfer arm extension finger  41  hits the free end surface of swinging stop arm  55 , which is placed in its lower stop position, as seen in FIG.  4 . This prevents transfer fingers  35  from pivoting into feed roller grooves  37 , to transfer the reserve web. Dispensing continues until stub roll  16  in the lower compartment runs empty. As the trailing end of the stub roll web passes over the rear side of main feed roller  11 , sensor fingers  47  pivot into feed roller grooves  37 , simultaneously raising cup-like sensor arm extension  53 , and the pivoted stop arm  55 . This releases transfer arm extension  39 , allowing the spring-loaded transfer arm  33  to pivot transfer fingers  35  into feed roller grooves  37 , under the bias of spring  43 , to thus transfer feed to the reserve web upon rotation of feed roller  11  (in the manner described in previous stage  3 ). As the reserve roll web moves around and down the back side of feed roller  11 , it contacts sensor fingers  47 , pivoting them back to once again ride on the surface of the web, simultaneously moving sensor arm extension  53  down, to once again let swinging stop arm  55  rest on top of the transfer arm extension finger  41 . The empty core in the lower compartment rests on the cover bottom. Thus, when the custodian later opens the cover to load a fresh reserve roll, the empty core will roll forwardly in the cover bottom where it can be easily removed. 
     The present invention has been described in terms of preferred and exemplary embodiments thereof Numerous other embodiments, modifications and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure.