Abstract:
A splicer for joining with tape the abutted ends of two sheets, such as the headers and footers of stacks of fanfold paper to be printed upon, is comprised of a clamp assembly and a tape dispenser. The clamp assembly captures the ends of the sheets between the resilient surfaces of a base and a movable top comprised of two spaced apart bars. Pins in the base help align perforated paper for joining. The dispenser runs along the slot between the two bars. It dispenses, presses down, and cuts the tape as it is laid along the butt-line between the ends of the sheets. An optional reversing bar causes the two sheets to travel along different shape paths to the splicer, thus enabling application of tape to the opposing sides of the sheets.

Description:
This application claims benefit of provisional patent application Ser. No. 60/063,986, filed Nov. 06, 1997. 
    
    
     TECHNICAL FIELD 
     The present invention relates to devices for joining together thin sheets of material, such as sheets of paper, particularly in connection with operations in the printing field. 
     BACKGROUND 
     In feeding paper and other sheet materials to printers and other kinds of finishing machines, it is often a desire that the feeding of sheet material be continuous. Thus, when the sheet material is supplied in batches, a first batch must be connected to the second batch upstream of the processing machine. While such a need is present when handling rolls of sheet material, it is particularly present when fanfold sheet and the like are being fed. Fanfold sheet is usually supplied in relatively small cartons or stacks which can be readily handled by an individual worker. Thus, for continuous operation, each small quantity of fanfold sheet must be joined to the other. More specifically, the tail end of the pages, or the “footer”, of a stack being used up must be joined readily and reliably to the first pages, or header, of the next stack to be processed. 
     Typically, fanfold paper will have perforated side edges suited for engagement by sprockets on the printing machine being fed. Thus, it is highly desirable that the hole-to-hole spacing across any splice be maintained. Splice joints must be made quickly and easily, and be strong and consistent. The splicing tape ought not run into the region where the sprocket-perforations are. Typically, the splice tape will have fine perforations running along its centerline, so that when the tape is used to make a splice, the fanfold sheet will not have a discrepancy insofar as fanfolding and segmentation is concerned. Thus, it is important that the perforation is carefully aligned with the joint between butt joined sheets. In the most basic way of joining sheets, an operator manually, and without mechanical guide, runs a piece of tape across the joint between the header and footer while they are hand-held in proximity. Different fixtures have been employed, and of course there are a variety of commercial holders for applying tape to the surfaces of objects. 
     Generally, the prior art splicing devices have either of two general types of inadequacies. Either they are cumbersome and slow to use, or they do not place the tape accurately. Consequently, there is a continuing quest for a splicer which has good performance, ease of use, reliability, and reasonable cost. The present invention is concerned primarily with satisfying such needs for joining fanfold paper sheets, in the context that any such improvement will have other applications. 
     SUMMARY 
     An object of the invention is to provide a way for making splice joints reliably and efficiently between the ends of sheets, particularly between headers and footers of stacks of fanfold paper. Another object of the invention is to provide in a splicer a tape dispenser which ensures that tape laid on a splice joint is well adhered across the whole length of the joint. 
     In accordance with the invention, a splicer for joining the ends of sheets is comprised of a clamp assembly and a dispenser. The clamp assembly is comprised of a base, and a top which is adapted to move toward and away from the base, preferably by pivoting. The top is comprised of two spaced apart bars running along the length of the base, thereby defining a lengthwise slot. The underside of each bar is surfaced with a first resilient material. The top surface of the base has a layer of second resilient material. When the clamp assembly top and base are mated, the two layers of first resilient material mate with the layer of second resilient material. Thus, when the ends of the sheets to be spliced are butted together within the assembly, so the butt line lies centrally along the length of the slot in the top, the sheet ends are frictionally held in place. A dispenser for applying tape to the joint is slidable lengthwise and vertically within the slot of the top. When the dispenser is moved along the slot, the dispenser lays down tape across the joint butt-line and automatically cuts it at the end. Thereafter, the clamp assembly may be opened and the spliced sheets removed. In different embodiments, the top may pivot or translate relative to the base, to open and close the clamp assembly. 
     Preferably, when perforated sheet is being spliced, there are sets of blocks having pin arrays on each side of the base. Each set is comprised of a rear block near the rear end of the base; and, a front block at the front end of the base. The rear block is preferably adjustably positioned along the length of the base, according to the width of paper being joined. The front block has an internal spring mechanism for biasing of the pin array away from the rear block. Thus, when the operator places the end of a perforated sheet on the base, the operator manually biases the front block toward the rear block, releasing it when the perforations of the sheet are engaged with the opposing block pin arrays, to thereby tension the sheet prior to closing the clamp. 
     As the tape dispenser is guided along the joint between the sheets, the tape is fed down the front part of the dispenser and laid on the joint by adhesive engagement of the tape with the sheets. The tip or lowermost part of the dispenser presses the tape onto the sheet surface as the dispenser moves. Preferably, the tape dispenser is pivotally mounted with a somewhat loose fit on the pivotable arm of a carriage assembly which is moved manually lengthwise along the top. That fit and the fit between the lower end of the dispenser and the slot in the top enables the dispenser to rock slightly in the plane transverse to the dispenser travel path. Thus, the lower end of the dispenser will maintain contact with the sheets, as the dispenser lower end runs over small variations and unevenness, ensuring good and continuous adherence of the tape. A wiper, supported off the carriage, rubs along the tape just behind the point of adhering. It&#39;s principal function is to ensure that the first laid, or beginning, portion of the tape is adhered. Proximate the end of the dispenser travel path along the joint, the dispenser is caused to rotate and lift, preferably by means of interaction of the dispenser and carriage with two cams on the base. A first cam engages a pin on the dispenser, rotating it slightly in the longitudinal vertical plane of the top. A second cam engages the carriage arm on which the dispenser is mounted, lifting it slightly. The rotating and lifting motion cause a knife located rearward of the dispenser bottommost tip to contact and cut the tape, while avoiding contact with the resilient strip on the base surface. The cam-induced motions also cause the tip of the dispenser to lift and the trailing edge of the lower end of the dispenser to contact the tape, so that the very last part of the tape which is laid down will be pressed firmly onto the sheet surface. 
     The splicer preferably has a vertical post extending downward to the machine at which splices are to be made, such as a stacker-feeder; and the post and related structures provide the splicer with a combination of vertical motion, two horizontal motions, and rotary motion about the post. Alternately, the splicer it is mounted from a dolly base or on a bench. The splicer optionally includes a reversing bar which is mounted at an elevation above the clamp, so that when a header or footer is run to the splicer it may be made to follow an S-shape curve path, while the other header/footer is made to follow a U-shape path. Thus the sides of sheet which are presented to the tape dispenser or other joining means are reversed, and the tape is placed on the underside of the sheet joint. 
     The foregoing and other objects, features and advantages of the invention will become more apparent from the following description of preferred embodiments and accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows schematically how the header and footer of stacks are spliced. 
     FIG. 2 is a perspective view of the base assembly and dispenser of a splicer mounted on a post, ready to receive sheets. 
     FIG. 3 is a side elevation view of portions of the device shown in FIG.  2 . 
     FIG. 4 is an partial cross section elevation view from the outer, or front, end of the splicer shown in FIG. 2, when the clamp assembly is in the closed position, just after sheets have been joined together by a piece of tape. 
     FIG. 5 is a top view of the top part of the device shown in FIG.  2 . 
     FIG. 6 is an exploded view of a dispenser and a carriage, showing how the dispenser-carrying carriage rides along rods on either side of the base of the splicer. 
     FIG. 7 is an elevation cross section view of a pin block which mounts on the base of the splicer. 
     FIG. 8 is an elevation view of the lower portion of a tape dispenser, showing how it dispenses tape. 
     FIG. 9 shows a cross section of the tape guide at front of the lower end of the tape dispenser. 
     FIG. 10 is a view like FIG. 8, illustrating the motion of the tape dispenser at the end of the dispenser travel path along the top of the splicer. 
     FIG. 11 is an end view like FIG. 4, showing an alternate configuration top. 
     FIG. 12 is a view like FIG. 1, showing the side of the sheet presented for splicing is reversed. 
     FIG. 13 is an elevation view of a splicer on a column which extends from a dolly base, with a bar above the splicer, to carry out the method illustrated by FIG.  12 . 
    
    
     DESCRIPTION 
     The invention is principally described in terms of joining together the ends of paper sheets, where the pages are the ends of fanfold sheets of the type familiarly used in the printing industry. The invention will be understood to be applicable to joining together of pieces of other types of paper, and to joining together of thin sheets of various other materials. Fanfold sheet is also commonly referred to as fanfold paper, fanfold pages and fanfold forms. All the foregoing are terms of art, referring to a continuous piece of sheet material (which commonly comprises cellulose pulp but may comprise some other material such as plastic, etc.), where the continuous sheet has periodic creases or serrations, so that when received at a point, the sheet folds in a zig-zag fashion to form a stack. The individual segments are referred to as pages herein. Fanfold paper commonly has spaced apart holes or perforations along the opposing side edges of the pages of the sheet, to engage sprockets on the machines handling or processing such kind of paper, for positive feeding. As was mentioned in the Background, the last pages from a first stack, or folded sheet, are called a footer; and, the first pages from a second stack, or folded sheet, are called a header, particularly when they are intended to be joined to each other, as is the case in this Description. Reference may be had to related U.S. Pat. No. 6,142,288, entitled “Fanfold Sheet Feeder Having Stack Postioner”, herewith, and common assignee. The Description thereof is hereby incorporated by reference. The related application describes how separate stacks of fanfold sheets are successively moved along a conveyor belt to a discharge point, and how the sheets of stacks are joined one-to-the-other for continuous output of fanfold sheet. 
     FIG. I illustrates schematically how a splicer  170  is used to connect the top pages or header  150 C of a second stack  126 C with the bottom pages or footer  152 B of first stack  126 B, which was previously deposited on a surface such as a conveyor belt  140 . FIG. II is a perspective view of the splicer components. Reference ought also be had to the side elevation view of FIG. III the end view of FIG. IV, the top view of FIG. V, and the exploded view of FIG. VI. FIG. IV shows the header and footer of two sheets clamped in the splicer just after a piece of tape  222  has been laid across the joint. 
     As illustrated by FIG. II, the splicer  170  is comprised of the tape dispenser  160  (shown with limited detail) and a clamp assembly  204 . Referring to the several Figures, the clamp assembly is comprised of a base  212 , having the shape of an inverted tee, and a pivotable top  207 . The top is comprised of two spaced apart and parallel bars  206 . The bars are joined together at the pivot end and outer end by connecting members  215  and  213  respectively. For illustration purposes, the outer connecting member  213  and pull-down handle  209  of the top are only shown in FIG. V. The top is pivotably mounted from the base by means of pin  209  at the uprights  211  which extend from opposing sides of the rear end of the base  212 . When a splice is made, the top is pivotably lowered onto the base as illustrated by the end view of FIG. IV. 
     A strip  210  of high frictional engagement rubber, for example, a 0.030 inch thick strip of neoprene rubber having a Shore A Durometer of about 70, runs along the length of the center of the top surface of the base. A strip  208  of comparatively thick (e.g. {fraction (3/16)} inch) foam elastomer, for example, polyvinylchloride foam rubber which has 25% deflection at 4 psi load, runs along the bottom surface of each bar  206 . The resilient strips have widths and relative locations such that, when the top is lowered onto the base  205 , they provide deflectable surfaces for accommodating irregularities of fit between the top and base, and surfaces for frictionally engaging the sheets, such as the header and footer of sheets  152 B,  150 C, very close to the point where they butt and are to be joined. See FIG. IV. 
     The sheets are initially held in position, before rotational closing of the top, by means of pins  218  at four locations. Two rear pin blocks  216 , each having an array of pins  218 , are mounted on opposing sides of the rear end of the base  212 . They are connected to each other by a mostly hidden bar  201  running through horizontal slot  203  of the base. See FIG. II and III. Two somewhat different construction front blocks  214 , also having pin arrays  218 , are attached to the base near the front end of the base. The pin sets are located at the outermost ends of the blocks, so the top surface of the block which runs lengthwise toward the center of the splicer provides support for the sheet which runs between the pins. 
     The front blocks  214  have essentially fixed positions. The rear blocks  216  are slidable lengthwise along the base length. They may be secured in any given lengthwise position by intentional heavy frictional resistance (about ten pounds breakaway force) within the slot  203  of their connecting bar, or by locking screws. The rear blocks  216  are set at a selected position along the length of the base, according to the width of the paper being handled. More specifically, the rear blocks  216  are set so that the distance L between the rear block pin sets and the front block pin sets is slightly greater than the distance between the rows of perforations on opposing sides of the sheet. See FIG. III. 
     With reference to the partial cutaway side view of FIG. VII, each front block  214  is comprised of a sub-block  223 , which is fastened to the flange of base  212  by screws  299 , and a cap  221  which is slidable on the sub-block. The cap is held onto the sub-block by main screw  227  which runs through, and moves freely laterally within, a slot  229  in the flange of base  221 . Spring  225  is captured within the sub-block  223 , to press on bushing  231 , exerting lateral force as a result on the screw  227  and the cap, Thus, any paper lying on the pins will be tensioned by action of the spring. The cap of the block is configured to slide lengthwise about ⅛inch. Thus, when a sheet is brought to the splicer, to be engaged with the spaced apart pin arrays of blocks  214  and  216  on one side of the base, the operator pushes the top of block  214  against the spring resistance to make the distance L smaller, sufficient to match the distance between the opposing perforated side rows of the sheet. The sheet end is first engaged with pins of block  216 , and it is then lowered onto the pins of block  214 . The operator then releases the manual force being applied to the cap, and the spring tension on cap  221  of each block  214  pulls the sheet taut. Typically, the springs provide the cap of a block  214  with an effective spring rate of about 15 pounds per inch. While the rectanguloid blocks shown are preferred, the term “blocks” is intended to encompass generally any structure carrying projecting pins, performing the functions which have been described, namely, to enable the pin arrays to engage and tension the opposing sides of a perforated sheet. It further should be understood that for operator convenience the front pin block is the spring-biased block, whereas in the generality of this aspect of the invention either the front or the rear, or both blocks may be spring biased. 
     When both sheet ends have been engaged with the pins on opposing sides of the base as just described, so they are tensioned, the top bars  206  are rotated downwardly to essential parallelism with the base  212 , so that the foam rubber of resilient strip  208  on the underside of the top presses each paper sheet against the resilient strip  210  on the top surface of base  212 . While pivoting is preferred, the top may be mated with the base by other means. Thus, in an alternative embodiment, the top may be cantilevered from one or more uprights at the rear of the base, sliding vertically along them; or the top may be a fully separate piece. While the force of gravity with manual downward operator force is usually sufficient to provide the required frictional force on the sheets, clamps or other load producing devices may be employed. 
     Once the sheets have been secured within in the clamp assembly so their butt ends mate, the tape dispenser  160  is moved lengthwise along the slot  205  of the top. How the splicer is constructed and guided along the length of the top is indicated by considering FIG. VI in combination with the other figures. The dispenser  160  is carried along the top by carriage assembly  233 , comprised of carriage  242  and arm  248 , so the dispenser lower end  200  runs within lengthwise vertical slot  205  of the top. The carriage  242  has internal bore holes  240  by means of which it mounts on rods  238 . FIG. VI indicates how the carriage will straddle the top bars  206 . Arm  248  is pivotally mounted from pivot pin  246  of the carriage  242 . The arm  248  has a sideways-projecting handle  220 , by which the operator causes the carriage assembly to move along the rails  238 . The arm  248  has a pin  232  which is received in pivot hole  237  of the tape dispenser  160 . The arm  248  also has a pin  252  which is adapted to engage a cam at the end of the travel path, to thereby cause the arm to pivot upwardly, as will be described. 
     The hole  237  of the tape dispenser  160  is made to fit a bit loosely on the mounting pin  232  of the arm  248 . This enables the dispenser to rock laterally a very small amount, in a plane transverse to the length of the clamp assembly. Thus, when the dispenser is mounted on the arm  248  and the carriage  242  is mounted the rods  238 , the lower end  200  of the dispenser  160  is positioned in the slot  205  between the spaced apart top bars  206 , in a manner such that the lower end of the dispenser will contact the sheets which are captured by the resilient strips of the clamp assembly, as described above. 
     To use the dispenser, the operator pulls the handle  220 , to move the carriage assembly and thus cause the dispenser to more along a rear-to-front travel path. The fit and engagement of the lower end  200  of the dispenser with slot  205  between the bars of the top is intentionally not precise for the same reason the fit between the dispenser and its mounting pin  232  is not precise, as mentioned above. However, the fit is sufficient to prevent the lower end from moving laterally (side to side relative to the length of the top) to any significant degree, because the lateral motion would undercut the desired positioning of a perforated tape so its perforations are aligned with the butt joint. 
     Contact of the bottom tip  226  of the lower end  200  of the dispenser on the sheet/tape surface controls the precise vertical location of the dispenser and the angular orientation in the vertical plane of travel. Thus, the dispenser is adapted to rock slightly in a plane transverse to the dispenser travel path, so it may accommodate any lengthwise and transverse unevenness along the joint being spliced. The accommodation helps ensure that the tape adheres to the sheets on both sides of the joint. FIG. XI is a end cross section view like FIG. VIII, showing a preferred top configuration particularly adapted to enabling the slight transverse rocking motion of the dispenser. Bars  206 A have a right angle cross section, and the inner edges provide relatively little depth to slot  205 . The inner edges of the slot are also made with a radius, so the lateral motion is controlled by the bottommost edges of the slot opening. 
     The operator&#39;s movement of the dispenser causes the dispenser to lay down tape, as will be next described. Because of the foam rubber cushions  208  on the underside of top bars  206  are placed in close proximity to the joint—with barely more space therebetween than is needed to lay down the tape, there is minimal tendency for the sheets to deform and for a “bubble” of paper to be created just ahead of the tape being laid, as the dispenser moves across the joint. 
     Referring to FIGS. IV, VIII, IX and X, a reel of tape  222  is mounted on a large diameter pin  227  at the upper end of the dispenser. Tape is drawn from the reel and passed vertically downward to the underside of the lower end  200  of the dispenser. FIG. IX shows in cross section how the front part of the lower end of the dispenser has a groove to guide the tape. Leaf spring retainer  224  at the front end of the dispenser also helps guide the tape by holding the tape against the body and within the groove. Various types of tape may be used. Tapes which may be used for paper sheets are No. 914 blue reputable adhesive tape and No. S338 clear matte acrylic adhesive tape,(Minnesota Mining &amp; Manufacturing Co., Minneapolis). 
     To apply tape and form the splice joint, the dispenser is first contacted with the abutting joint sheets within the closed clamp assembly, at the rear end of the slot. The dispenser is moved lengthwise, as shown by the horizontal arrow in FIG. VIII, to thereby deposit the tape  222  on the surface of the abutting sheets, where they lie on strip  210 . Adhesive engagement of the tape with the sheet draws tape from the reel as the dispenser is moved along slot  205 . A wiper  254  is attached to the arm  248  of the carriage. The wiper is made of thin flexible steel, like that of a leaf spring, and has a plastic cap at the lower where it contacts the tape. The wiper  254  presses on the tape as it is being laid. It has the primary function of ensuring that the first portion of the tape laid down, that nearest the rear end of the clamp assembly, is pressed fully against the paper. 
     When the dispenser is moved to near the end of its travel path within the slot  205  it serially engages cams  236 ,  235  which are mounted at the end of the front end of the top. The cams are schematically illustrated in FIG. VI. From the text (and associated drawings) which follows, it will be appreciated that an artisan can choose different structures for the cam, so long as the working surfaces of the cams are positioned to interact with the pins on the carriage assembly and dispenser in the way described. Of course, other mechanisms may also be subsituted for the pins and cams to achieve the particular dispenser movements. 
     Referring to FIG. X, pin  234  of the dispenser engages first cam  236  and that causes the whole dispenser, and thus most particularly the dispenser lower end  200 , to rotate about pin  232 . The rotation causes the tip  226  to lift from the paper, and with it the tape proximate the tip since, as illustrated, the trailing edge comer  230  tends to contact the tape surface where it lies on the sheet. The rotation causes knife  228  to be brought toward contact with the tape. 
     Precisely correlated with the dispenser movement just described is the contact of pin  252  of the arm  248  with a second cam  235 , not shown in FIG. X. The contact causes the arm to pivot upwardly about pivot  246 , thus lifting upwardly a small distance the pin  232  and the dispenser mounted thereon. The resultant crooked path which pin  232  (and thus the dispenser) follows near the end of the dispenser travel path is nominally indicated by dashed line  256  in FIG. X. The dispenser does not continue on the upwardly angled path but for a short distance (less than the dashed line suggests for graphic purpose), sufficient to lift the lower end of the dispenser upwardly slightly from the surface of the paper sheets. As the motion continues with the dispenser rotating and moving upwardly at an angle, the trailing edge  230  of the lower end of the dispenser rubs on the tape which is on the sheet. The rotation and lifting motion of the dispenser also cause the knife  228  to cut the tape, while avoiding any cutting of the knife into the rubber  210 . With continued motion, the dispenser trailing edge  230  presses the cut-end of the tape onto the paper, to complete the splicing. Then the top  207  of the splicer is pivoted upwardly, carrying with it the dispenser and carriage assembly. The carriage assembly and dispenser are then returned to the starting point at the rear of the top. 
     It will be appreciated from the Figures, that to accomplish the above described result, the tip  226  is the lowermost part of the dispenser when it is moving along the dispenser travel path, except when the cams are engaged. The rounded trailing edge  230  at the rear part of the lower end has an elevation higher than the tip except when the cams are engaged. Likewise, the cutting edge of the knife is intermediate in elevation between the rear and front parts. 
     While the foregoing motions are lengthy in explanation, the operation of the dispenser is quick and easy, with minimal skill required by an operator to get reliable and reproducible results. When the sheets being joined do not have perforated holes for sprockets, the operation is the same except for those which are peculiar to engaging the holes. Various mechanical guides may optionally be attached to the base, to guide the edges of the sheets and thus assure a well aligned joint. While a particular dispenser riding on a carriage, as has been described, is much preferred, other dispensers may be used within the generality of the invention which involves the clamp assembly and associated structures. 
     Referring again to FIG. II and III, the splicer clamp assembly  204  is typically mounted on top of, and cantilevered from, a column  190  which extends upwardly from a machine base, or a wheeled dolly  177  as shown in FIG. XIII, or other support. 
     When the column is fixed to the base of a machine such as a belt conveyor, FIG. III shows how the splicer may be laterally adjusted. A block  191  is fastened to the top of the column  190 . The block has two bore holes to slidably receive base rods  193  attached to the underside of the splicer base  212 . This enables the splicer to be moved laterally relative to the column to a desired horizontal position. 
     The column  190  may be fabricated with swivel support structure that provides a desired combination of vertical or rotary motion to the column  190 . 
     It is sometimes desired that a splice be made on the underside of the sheet. This is accomplished by the method illustrated schematically by FIG. XII, which ought be compared to FIG. I. One of the sheet ends being joined, the header, or the footer  152 B as shown in the Figure, is run along an S-shape curve, over the cantilever bar  171  which is positioned above the splicer  170 , and then into the splicer. The other sheet end, header  150 C, is run underneath the splicer, so it follows a U-shape path, and enters from the side opposite from which it would normally be entering. The tape is applied by the dispenser as described, to the underside of the sheets. The splicer clamp is opened and the spliced sheet is slid off the end of the reversing bar  171 . FIG. XIII shows how the reversing bar  171  is mounted above a splicer, by being fastened to the splicer base. Alternatively the bar may be fastened otherwise, such as from the column  190  which extends from wheeled dolly  177 . The bar  171  is preferably made of light weight tubing and as a folded-U, so there are parallel members running from the splicer to the U-connection at the tip of the bar. Of course, the reversing bar technique can be employed with other types of splicers than that described herein and for other than fanfold stacks. 
     Although this invention has been shown and described with respect to a preferred embodiment, it will be understood by those skilled in this art that various changes in form and detail thereof may be made without departing from the spirit and scope of the claimed invention.