WO1991014510A1

WO1991014510A1 - Bookbinding apparatus having an adhesive applicator head

Info

Publication number: WO1991014510A1
Application number: PCT/US1991/002133
Authority: WO
Inventors: Fred A. Slautterback; W. Harrison Faulkner, Iii
Original assignee: Slautterback Corporation
Priority date: 1990-03-29
Filing date: 1991-03-27
Publication date: 1991-10-03

Abstract

An apparatus for applying adhesive to the downwardly facing backbone (86) of a book (16, 18) from a remote supply of adhesive to a low volume applicator head (14). The applicator head has an extrusion slot (84) defined by a space between a slot body (66) and a blade (68). The thickness of the adhesive on the backbone of the book can be adjusted by adjustment of the blade relative to the slot body. Slidably coupled to the applicator head is a pair of clamp members (34, 36) which exert compression forces on the opposed sides of the book block (16, 18) as the book block progresses past the extrusion slot. Slot seals (92, 94) are sandwiched between the applicator head and the clamp members so that lateral movement of the clamp members varies the length of the extrusion slot. The slot seals are spaced apart from each other by a greater distance than the clamp members to define a recess for entrance of adhesive at opposed sides of the book block.

Description

Bookbinding Apparatus Having An Adhesive Applicator Head

Technical Field

The present invention relates generally to bookbinding apparatus and particularly to apparatus for applying adhesive to a plurality of sheets to be bound.

Background Art

In the bookbinding industry it is customary to apply adhesive to the back of a collated assembly of pages. Typically, hot-melt. adhesive is used.and is ap- plied to the downwardly facing backbone, or spine, of the book. The bound book block is then trimmed to remove portions of the collection of pages. Trimming of at least 0.25 inches from opposed edges of the book block is common. The waste from the trimming operation is recy- cled, but the value of the waste is significantly reduced if the trimmed portion includes adhesive.

U.S. Pat. No. 4,677,005 to Riesmeier et al., 4,512,945 to Vigano and 4,137,120 to Shimizu teach three methods of applying adhesive to a book block. The method described in Riesmeier is the most commonly accepted method. This method employs a rotating application roll¬ er to transfer a film of glue to the book block. The application roller receives the glue which is subsequent¬ ly transferred to the book block from a "dip and dosing" roller which runs in a reservoir containing glue. That is, the application roller receives a film of glue from the dip and dosing roller and transfers the film to the moving book block. Typically, there is more than one roller which comes into close proximity to the book block, with the last roller functioning much like a doc¬ tor blade. Other patents which teach the use of an ap¬ plication roller within an open containment of adhesive are 4,484,850 to Shimizu and 3,866,568 to Mina i. The method of Vigano likewise teaches a high volume contain¬ ment of adhesive proximate to the application of adhesive to the book block. However, instead of use of a roller to bring the adhesive to the downwardly facing spine of the book, compression members within the containment are moved laterally toward and away from each other to force adhesive through an array of apertures for application to the book. U.S. Pat. No. 4,201,615 to French describes both the roller-apply method of Riesmeier et al. and the aperture array-apply method of Vigano.

The third of the three above-identified meth¬ ods, as taught by Shimizu ('120), is similar to the other methods in that it includes a containment of adhesive at the application region. An adhesive applicator plate is normally dipped in the container of adhesive. The appli¬ cator plate is raised from the adhesive container and brought into contact with the backbone of a book, where¬ after the applicator plate is again lowered into the con¬ tainer. A scraper rod may be provided to scrape excess adhesive off the back of the book.

Large containments of adhesive at the applica¬ tion region are associated with a number of problems. For example, it is difficult to make adjustments to ac¬ commodate various size book blocks bound at different times. Hot-melt adhesive is a dense material and the mass of such material within an adhesive pot causes difficulty in accurately setting the height relative to the travel of the book block. This relative positioning is important in controlling adhesive thickness. Typical- ly, resolution is measured in terms of thousandths of an inch.

Moreover, an open pot of adhesive tends to ac¬ cumulate a buildup of char and adhesive degradation. Cleaning of the pots of adhesive can be a labor-intensive task. This aspect works against use of moisture cure adhesive in the bookbinding industry. Hot-melt thermal setting urethane adhesive has a thermal stability that can be extruded as a hot-melt adhesive to form an initially high green hot-melt bond and can moisture cure to a rigid moisture cure polyurethane bond. However, the reactive material cannot be heat reactivated after ther¬ mal setting. Thus, in the open pots of current bookbind- ing machinery, a user must undergo the labor-intensive task of cleaning each open adhesive pot following each assembly line shutdown.

Other problems associated with containment of adhesive at the application area of adhesive to the book block include emission of fumes and maintenance consider¬ ations. Exposed glue pots typically require fume exhaust hoods. Whether covered or not, high volume containments of hot-melt adhesive at the application region present a risk of injury to persons making adjustments or^" repairs within that region. Moreover, paper particles collect^' at the application area and tend to contaminate the contain¬ ment.

As noted above, after the hot-melt adhesive has been applied to the book block, a significant portion of the book block is trimmed and the trimmed waste is recy¬ cled. The value of the trimmed waste is reduced if it contains adhesive. Use of the application rollers to apply adhesive creates difficulties in limiting adhesive to the portion of the book backbone which will remain after trimming. Other methods tend to wipe the adhesive onto trailing portions of the book block after adhesive cutoff has occurred.

It is an object of the present invention to provide an apparatus for applying adhesive to the back- bone of a linearly moving book, wherein the above- mentioned problems associated with adjustments, fumes, maintenance and frequency of cleaning are overcome.

Summary of the Invention The above object has been met by an adhesive- apply apparatus having an applicator head which is spa¬ tially remote from a supply of pressurized adhesive. The applicator head functions merely to channel the flow of adhesive from the remote supply to the desired regions of the book block. Adhesive is applied to a downwardly- facing backbone of the book block, as well as small "roll up" portions of the opposed sides of the book block. A hose or the like is used to direct a pressur¬ ized flow of viscous adhesive from the remote supply to the adhesive applicator head. The applicator head is heated to prevent setting of the hot-melt adhesive within the applicator head. The low-volume applicator head has a face which is directed upwardly to intersect the path of linearly moving book blocks. The face of the applica¬ tor head is defined by first and second longitudinal sides which are spaced apart by a shim to form an extru¬ sion slot. The passageway through the applicator head includes an inlet which is coupled to the. hose and in¬ cludes the extrusion slot which is in fluid communication with the inlet.

The applicator head includes a pair of clamp members at opposed ends of the extrusion slot. Fixed to the bottom of each clamp member is a seal which obstructs flow from that portion of the extrusion slot contacted by the seal. The clamp members are slidably coupled to the applicator head to accommodate various size book blocks. The clamp members are spaced apart such that the opposed sides of the book block are contacted by the members. Relative to the book block, the seals are recessed to permit a roll up application of adhesive to the sides of the book block.

The first and second longitudinal members of the applicator head are offset relative to each other.

That is, with respect to book travel, the forward longi¬ tudinal member is spaced apart from the backbone of the book block by a distance greater than is the rearward longitudinal member. This offset plays a role in deter- mining the film thickness of adhesive applied to the backbone, as well as a role in the pressure of the adhe¬ sive as contact is made with the backbone of the book. The first and second members are coupled to each other in a manner to provide variation of the offset.

An advantage of the present invention is that any high volume containment of adhesive is spatially re- mote from application of adhesive to a book block. This reduces the risk of injury during routine maintenance and during adjustment at the application area. It also pre¬ vents paper particles from collecting within the contain¬ ment of adhesive. Another advantage is that the present invention permits high resolution adjustments. The thickness of the shim between the two longitudinal mem¬ bers determines the width of the extrusion slot and, therefore, affects the volume of adhesive exiting the extrusion slot. The adjustable offset of the two longi- tudinal members influences the thickness of the adhesive along the book block. Repositioning of the clamp members accommodates changes in the size of the book block. The present invention also includes mechanisms for adjust¬ ments of applicator head angle, and vertical and horizon- tal movement of the applicator head relative to the path of book travel.

A further advantage of the present invention is that adhesive application does not include an open pot of adhesive. Thus, the emission of fumes into the atmos- phere is significantly reduced. More importantly, it is possible to use moisture cure hot-melt adhesive without exposure of a containment of adhesive to the atmosphere, where such exposure initiates setting of the adhesive. Still other advantages are the provision of a roll up to the opposed side of the book block and an ability to stitch adhesive patterns for a saving of up to 50% of the adhesive used in the binding of books.

Brief Description of the Drawings Fig. 1 is a perspective view of an applicator head for the binding of books in accord with the present invention. Fig. 2 is a side sectional view of the applica¬ tor head of Fig. 1, taken along lines 2-2.

Fig. 3 is a rear sectional view of the applica¬ tor head of Fig. 1, taken along lines 3-3. Fig. 4 is a rear sectional view of one- edge of a book block secured in position relative to the applica¬ tor head of Fig. 3.

Fig. 5 is a side view of an alternative embodi¬ ment of the applicator head of Fig. l. Fig. 6 is a top view of a second alternative embodiment of the applicator head of Fig. 1.

Fig. 7 is a perspective view of a book block traveling past the applicator head of Fig. 1.

Best Mode for Carrying Out the Invention

With reference to Fig. l, the adhesive applica¬ tion apparatus includes a mounting member 10 which is fastened to a support structure, not shown. Bores 12 within the mounting member permit fastening to the sup- port structure by externally threaded bolts or the like. Mounting of the apparatus positions an applicator head 14 directly below the path of linearly moving book blocks 16 and 18-. Arrow A indicates the direction of travei of the book blocks. "Book" and "book blocks" are each defined as a collection of pages to be bound together and are not limited to collated pages containing writing.

The relative positioning of the applicator head 14 to the linearly moving book blocks is important. A pair of control wheels 20 and 22 permit accurate regis- tration. Rotation of the control wheels by means of han¬ dles 24 -causes vertical and horizontal displacements of - the applicator head. For example, rotation of the con¬ trol wheel 20 turns a journal 26 to vertically move the applicator head relative to the fixed mounting member 10. In like manner, rotation of the control wheel 22 provides horizontal registration of the applicator head.

The angle of the applicator head 14 may be ad¬ justed by movement of a projection member- 28 within an arcuate slot 30 of a side bracket 32. The projection member 28 is moved within the arcuate slot, as shown by arrow B, until the applicator head is angled correctly. The applicator head is then fastened in position. In addition to the vertical, horizontal and angular adjustments described above, the applicator head 14 includes a pair of spaced apart side guide clamp mem¬ bers 34 and 36 which are slidably attached to opposed ends of the applicator head. As the book block 16 progresses past the applicator head, the side guide clamp members exert compression forces on the opposite sides of the book block. The clamp members 34 and 36 may be se¬ lectively moved closer or farther apart to accommodate book blocks of varying sizes. The lower ends of the clamp members are sandwiched between lock brackets 38 and 40 and a metallic block 42. Adjustment of the clamp mem¬ bers 34 and 36 is accomplished by loosening of the fas- . tening screws which hold the lock brackets to the metal¬ lic block so as to release the lower ends of the clamp members. The clamp members should contact the opposite sides of the book block, whereafter the lock brackets 38 can again be fastened to securely capture the clamp mem¬ bers. Machined into the clamp members are recesses 44 and 46. With respect to book travel, the recesses are at the rearward sides of the clamp members. These recesses aid in guiding the lead corners of each book block as the book block approaches the applicator head 14.

Pressurized hot-melt adhesive from a remote supply is brought to the applicator head 14 via hoses 48 and 50 connected by a fastening nut 52. The melted adhe¬ sive enters a solenoid valve 54. Actuation of the sole¬ noid valve regulates fluid communication between the sup¬ ply and the applicator head 14. Adhesive flow from the solenoid valve is through a heater member 56 having ^• thermal units, not shown, to maintain the adhesive in a melted state. Electrical power and control signals for the thermal units and the solenoid valve are supplied via a conduit 58. The coupling assembly of the heater member 56 to the applicator head 14 includes a pair of swivel nuts 60 and 62 which provide an inelastic coupling and allow for dimensional tolerances of the interconnected parts. A heat transfer block 64 provides a heat flow path that is separate of the adhesive flow path from the heater member 56 to the applicator head 14. The heat transfer block is made up of material having a high ther¬ mal conductivity, such as aluminum. Provision of a heat flow path that is separate from the adhesive flow path avoids the extra expense and complexity that would result from adding a second heating unit to the applicator head 14. Preferably, the heat transfer block either includes or is operatively coupled to a mechanism for oscillating the application head vertically to aid in driving adhe¬ sive into the interstices of the backbone of the book 16. Referring now to Figs. 2 and 3, the applicator head 14 includes a slot body 66, a blade 68 and a shim 70 which is captured between the slot body and the blade. The three elements 66, 68 and 70 include corresponding bores 72, 74 and 76 to receive a fastening bolt, not shown, to secure the elements together. The slot body 66 has an upwardly extending adhesive passageway 78 having an inlet 80 in fluid communication with the solenoid de-. scribed above for regulating flow of adhesive to the ap¬ plicator head 14. 'At the end of the passageway 78 oppo¬ site the inlet 80 is an elongated opening 82. The shim 70 is a C-shaped member which is open at an upper end. Because the shim spaces the blade 68 apart from the slot body 66, the open end of the shim defines a gap for ex¬ trusion of adhesive. Referring briefly to Fig. 7, the thickness of the C-shaped shim defines the width of an extrusion slot 84 between the slot body 66 and the blade 68. Referring now to Figs. 2-4, the elongated open¬ ing 82 in the slot body 66 feeds adhesive to the extru¬ sion slot 84 between the slot body and the blade 68. The adhesive is applied to the backbone 86, or spline, of the book 16. As noted above, the applicator head includes a pair of side guide clamp members 34 and 36 which apply compression forces to the opposed sides of the book 16 as the book progresses past the applicator head. A second pair of clamps 88 and 90 is shown in Fig. 4. Unlike the fixed side guide clamp members 34 and 36, the clamps 88 and.90 travel with the book 16 during the bookbinding process.

Captured between each side guide clamp member 34 and 36 and the applicator 14 is a slot seal 92 and 94. The slot seals are attached to the laterally slidable clamp members 34 and 36. The slot seals are preferably made of an elastomeric material and seal that portion of the extrusion slot 84 covered by the seal. The laterally slidable clamp members 34 and 36 are positioned to con¬ tact the sides of the book block 16. The slot seals 92 and 94, on the other hand, are spaced apart from the sides of the book to define recesses 96 and 98. The re¬ cesses 96 and 98 allow adhesive to reach the sides of the book nearest the backbone 86. This "roll up" aspect is important. in the bookbinding industry.

An alternative embodiment of an applicator head 100 is shown in Fig. 5. Adhesive from a remote supply, not shown, is channeled to a solenoid 102. Activation and deactivation of the solenoid regulate flow through a heater member 104 into a manifold 106. A nut 108 on an externally-threaded shaft 110 is used to couple the com¬ ponents. An inelastic, leak-resistant fitting to the manifold is provided by the combination of an 0-ring 112 and a friction coupling of a protrusion from the shaft 110 into the tapering entrance bore 114 of the manifold 106. Sandwiched between the heater member 104 and the manifold 106 is a metallic block 116 having a high ther¬ mal conductivity. Adhesive flow through the manifold 106 follows a T-shaped path. The adhesive from the manifold enters into extrusion slots 118 and 120 between the manifold and opposed blades 122 and 124 which are fixed to the manifold by bolts 126. Fixed to the top of the manifold is a carbide insert 128.

Like the applicator head described above, the applicator head 100 of Fig. 5 includes side guide clamp members 130 and slot seals 132, only one of which is shown. The clamp members 130 are slidably fixed to the manifold 106. Lateral movement of the clamp members to accommodate various size book blocks is provided by loos¬ ening of screws 134 to release pressure of block brackets 136 against the clamp members.

A shim, not shown, prevents downward flow of adhesive from a manifold 106 to the areas between the manifold and the two blades 122 and 124. Thus, adhesive flow is limited to the extrusion slots 118 and 120 for application to a book block. The blades are adjustable relative to the height of the carbide insert 128. Pref¬ erably the first blade 122 is adjusted so that the first extrusion slot 118 provides a thin film layer of adhe¬ sive. The edge of the carbide insert may have a curved surface to increase the pressure of the adhesive into the areas between individual pages of the book block. The second blade 124 should have a height slightly less than the height of the edge of the carbide insert. In this manner, the adhesive film applied by the second- extrusion slot 120 will have a greater thickness than the film ap¬ plied by the first extrusion slot 118. An offset of the second blade 124 relative to the edge of the carbide in¬ sert not greater than 0.0010 inch is preferred.

A third embodiment of an applicator head 138 is shown in Fig. 6. This embodiment includes an alternative method of adjusting the length of an extrusion slot 140. The extrusion slot is defined by the spacing between a pair of adjustable members 142 and 144. Each adjustable member is contacted at opposed ends by the extremities of bolts 146 and 148. The midportion of each bolt is threaded into a fixed bracket 150 and 152. Rotation of the bolts within the brackets causes displacement of the adjustable members 142 and 144. The relative positioning of the adjustable members determines the length of the extrusion slot 140. The applicator head 138 includes a pair of side guide clamp members 154 and 156. The clamp members are slidably attached to the applicator head. Referring to Figs. 1-4 in general and Fig. 7 in particular, in operation the applicator head 14 applies a film of adhesive to the backbone of a book 16, as well as a roll up portion 158 of each side of the book. It has been discovered that a pre-heating of the backbone .sig- nificantly improves the strength of the bond. The lead¬ ing edges of the book block are guided into the proper position relative to the extrusion slot 84 by machined recesses 44 and 46 within the side guide clamp members 34 and 36. Preferably, the blade 68 is offset relative to the slot body 66. That is, the height of the blade 68 is lower than the height of the slot body. The offset of the blade determines the thickness of the adhesive layer 160 on the backbone of the book 16. As best seen in Fig. 2, the bores 72 and 74 which receive the bolts, not shown, that attach the blade 68 to the slot body 66 may be such as to allow adjustment of the offset of the blade 68. This adjustment may also be made by any other me¬ chanical mechanism known in the art. As shown in Figs. 4 and 7, the book block 16 is held above the level of a slot body 66 and shim 70. Thus, the thickness of the adhesive layer 160 on the backbone of the book block 16 is greater than the offset of the blade-. Preferably, the offset of the blade is within the range of 0.001 inch and 0.01 inch. The pre¬ ferred thickness of the adhesive film is within the range of 0.005 inch and 0.015 inch. These measurements, howev¬ er, are not critical.

As noted above, the applicator, head 14 may be oscillated vertically to aid in pressurizing adhesive into the interstices of the backbone of the book 16. The frequency of oscillation will affect adhesive pressure at the area of application, and may be an ultrasonic fre¬ quency.

The thickness of the slot seal is approximately 0.02 inch. This thickness is a factor in the determina- tion of the roll up portion 158 onto the sides of the book block 16. Downstream with the path of the book block 16, the side guide clamp members 34 and 36 have machined notches 162, as shown in Fig. 7. The notches are approximately 0.125 inch from the center of the ex- trusion slot 84, but this is not critical. The function of the notches 162 is to reduce the likelihood of contin¬ ued application of adhesive to the book block after cut¬ off by the applicator head 14. While the adhesive layer . 160 is shown as beginning at the lead edge of the book 16, in practice the lead and trail ends of book blocks do not receive adhesive. After the application of adhesive, the lead and trail ends of the book block are typically trimmed to produce a book of the desired size. The por¬ tions of the book block which have- been trimmed are sold as waste. The value is significantly affected by the presence of adhesive. Here, the notches 162 prevent the side guide clamp members 34 and 36 from wiping adhesive onto the trail regions of the book block after adhesive cutoff, thereby increasing the value of the paper waste. AS best seen in Fig. 1, the present invention allows for a number of adjustments for proper application of adhesive to the book blocks 16 and 18. Control wheels 20 and 22 adjust the vertical and horizontal positioning of the applicator head 14 relative to the path of the book blocks. Angular positioning of the applicator head is provided by movement of the projection member 28 with- - in the arcuate slot 30. The side guide clamp members 34 and 36 are able to slide along the surface of the appli¬ cator head-to accommodate book blocks of various sizes. Because the slot seal is attached to the slidable clamp members 34 and 36, movement of the clamp members adjusts the length of the extrusion slot of the applicator head. The width of the extrusion slot is adjustable by replacement of the shim which is sandwiched between the slot body 66 and the blade 68. A final adjustment is the adjustment of the offset of the blade 68 relative to the height of the slot body 66. This offset plays a function in determining the thickness of the film of adhesive ap¬ plied to the backbone of the book, as well as the height of the roll up portion of adhesive onto the sides of the book block.

Because the applicator head 14 is a low volume head for applying adhesive from a remote supply, the present invention does not require an open pot of adhe¬ sive and minor adjustments can be made without movement of a large mass of adhesive. While the applicator head may be used with other adhesives, it is particularly adapted to use of hot-melt thermal setting urethane adhe¬ sive which has a thermal stability that can be extruded as a hot-melt adhesive to form an initially high green hot-melt bond and which can moisture cure to a rigid polyurethane bond. Application of such reactive material from a remote supply facilitates use of the material in the bookbinding industry.

Claims

1. An apparatus for applying adhesive to a downward fac¬ ing backbone of a linearly moving book comprising, hose means for receiving a pressurized flow of viscous adhesive from a remote supply of adhesive, a low volume adhesive applicator head coupled to said hose means to channel said flow of adhesive, said applicator head having a continuous passageway there¬ through having an upstream end in fluid communication with said hose means and having an upward facing extru¬ sion slot, said extrusion slot having a length generally perpendicular to book travel, an upper portion of^"said applicator head adjacent to said extrusion slot having a dimension parallel to said book travel substantially less than a book to receive adhesive, and means for positioning said book adjacent to said extrusion slot so as to receive adhesive exiting therefrom.

2. The apparatus of claim 1 wherein said applicator head includes first and second members having longitudinal sides spaced apart from each other to define said extru¬ sion slot, said longitudinal sides having dissimilar ex¬ tents in a direction perpendicular to the lengthwise di¬ rection of said sides, one of said first and second mem¬ bers thereby being spaced apart from said means for posi¬ tioning said book by a distance greater than is the other of said members.

3. The apparatus of claim 2 wherein, with respect to said book travel, said first and second members are rear¬ ward and forward members, respectively, said forward mem¬ ber being spaced apart from said means for positioning said book by a greater distance than said rearward mem¬ ber.

4. The apparatus of claim 2 wherein said applicator head includes means for coupling said first and second members such that extent of said second member is selectively varied.

5. The apparatus of claim 1 wherein said positioning means includes a pair of side guides coupled to said ap¬ plicator head and includes slot-length varying means for fixing said side guides to said applicator head at said extrusion slot, said side guides having the characteris¬ tic of obstructing adhesive flow from said extrusion. - slot.

6. The apparatus of claim 5 wherein said side guides each include a slot seal and a clamp member, said side guides disposed on opposed sides of said extrusion slot and said clamp members contacting opposed sides of said book, said slot seals being spaced apart from each other by a greater distance than said clamp members to define a recess for entrance of adhesive at opposed sides of said book.

7. The apparatus of claim 1 wherein said extrusion slot is a first extrusion slot and wherein said applicator head includes a second extrusion slot parallel to said first.

8. An apparatus for applying adhesive to a downwardly facing backbone of a book comprising, a supply of pressurized adhesive, conduit means for channeling adhesive from said supply, an applicator head having an inlet spaced apart from said supply and in fluid communication with said conduit means, said applicator head having a longitudinal extrusion slot in communication with said inlet, solenoid means coupled to said applicator head for selectively blocking flow of pressurized adhesive from said conduit means, . means slidably fixed to said applicator head for selectively obstructing selected portions of the • length of said extrusion slot, mounting means for securing said applicator head in a desired position, means for providing a relative movement of said book adjacent to said extrusion slot of said applicator head, and compression means for contacting opposed sides of said book during said relative movement.

9. The apparatus of claim 8 wherein said compression means is a pair of clamps slidably coupled to said appli¬ cator head at said extrusion slot, said slidable coupling providing adjustment of said clamps to contact books of varying sizes.

10. The apparatus of claim 9 wherein said obstructing means includes a pair of seals, each seal being fixed to one of said clamps to slide therewith and being sand¬ wiched between said clamp and said applicator head at said extrusion slot.

11. The apparatus of claim 8 wherein said applicator head includes first and second members, said first and second members having longitudinal sides spaced apart to define said extrusion slot, said applicator head further including means for selectively fastening said second member at a desired distance from said book.

12. The apparatus of claim 11 wherein said second member is spaced apart from said book by a distance greater than is said first member.

13. An apparatus for applying adhesive to the downwardly facing backbone of a book comprising, a low volume applicator- head having•a• face which is directed upwardly, said applicator head having an adhesive inlet, said face having first and second longitudinal sides spaced apart to define an extrusion slot, said extrusion slot being in fluid communication with said adhesive inlet, means for providing relative motion between said book having said downwardly facing backbone and said extrusion slot, said second longitudinal side being spaced apart from said book by a distance greater than is said first longitudinal side, with respect to said rela¬ tive motion said first and second longitudinal sides be¬ ing rearward and forward sides, respectively, compression means for exerting forces at opposed sides of said book during said relative movement as said book.progresses past said extrusion slot, said compression means including opposed clamp members slida¬ bly coupled to said applicator head, a pair of seals in fluid obstructing relation with said extrusion slot, each seal being fixed to one of said slidably coupled clamp members for movement there¬ with, movement of said seals varying the length of said extrusion slot exposed to said book, and supply means for providing pressurized adhesive to said adhesive inlet of ^"said applicator head.

14. The apparatus of claim 13 wherein said seals are recessed relative to said clamp member such that said seals are spaced apart from each other by a greater dis¬ tance than are said clamp members spaced apart from each other.

15. The apparatus of claim 13 wherein said face of said applicator head has a profile partially defined by down¬ wardly sloped surfaces of said first and second longitu¬ dinal sides.

16. The apparatus of claim 13 wherein said first and. second longitudinal sides are spaced apart by a shim, the width of said extrusion slot being determined by the thickness of said shim.