Wrapping apparatus for a book cover production machine

Wrapping apparatus for use in the production of book covers employs wrapping systems for folding an overlay sheet around the leading and trailing edges of a cover board and subsequently clamping the folded-over overlay and cover board together for a defined period of time. The wrapping systems each comprise a tiltably mounted wrapping rail, controlled in a displacement-dependent mode, which cooperates with an associated support rail to form a clamp.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to the manufacture of books and particularly 
to the application of overlays to the cover boards of hard cover books. 
More specifically, this invention is directed to wrapping apparatus for 
book cover production machines and especially to apparatus for folding the 
overlay material, which projects beyond the leading and trailing edges of 
a cover board, around the said edges and holding the thus folded overlay 
in contact with the continuously moving board. Accordingly, the general 
objects of the present invention are to provide novel and improved methods 
and apparatus of such character. 
2. Description of the Prior Art 
U.S. Pat. No. 2,749,967 discloses apparatus for use in the production of 
book covers wherein the wrapping of the overlay material around the edges 
of the backing board, the backing board and overlay moving continuously 
along a conveyor system, is accomplished by wrapping the side edges prior 
to the wrapping of the leading and trailing edges. In the patented 
apparatus, in order to accomplish wrapping of the side edges, the cover 
units comprising the board and an oversize overlay which has previously 
been bonded thereto are clamped and fed through the apparatus by transport 
chains. The overlay is first turned upwardly and subsequently folded back 
around the board side edges by means of wrapping shafts which travel with 
the cover units, the wrapping shafts being movable inwardly with respect 
to the cover unit. Subsequently, the cover units, supported on an endless 
and continuously moving transport belt, are delivered to a folding 
mechanism which is installed above the movement path defined by the belt. 
The folding mechanism, which can be selectively translated into the path 
of movement of the cover units, wraps the overlay around the leading edge 
of the board. This wrapping is accomplished by the use of wrapping fingers 
which are positioned transversely with respect to the direction of 
movement of the cover unit. The wrapping fingers are mounted side-by-side 
on a shaft and are spring loaded so as to rest against a hold-down shaft 
when in the retracted position. The wrapping fingers are lifted against 
their spring bias by the moving cover units so as to be swung upwardly and 
out of the plane in which the cover units move. 
Continuing to discuss the apparatus of U.S. Pat. No. 2,749,967, as a result 
of the movement of the wrapping fingers around the leading edge of a cover 
unit, the overhanging overlay material is folded around the leading edge 
of the board. The folded overlay is then pressed into contact with the 
board by means of pressure rollers which follow the wrapping fingers. The 
trailing edges of the cover boards are wrapped in an analogous manner, but 
by means of wrapping rails that are installed on driven chains which move 
on endless paths. These wrapping rails are propelled, for a short period, 
at a speed in excess of that at which the cover units move. The wrapping 
rails, when overtaking the moving cover unit, come to bear thereagainst 
and i so doing overcome a spring force. In order to prevent the action of 
the trailing edge wrapping rail from pushing the cover unit forwardly, 
motion retarding fingers which act on the leading edge of the cover are 
provided. Pressure rollers, resiliently mounted at locations such that 
they follow the wrapping rail, serve to press the overlay material against 
the board once the folding action has been accomplished by the rail. 
The above briefly described book cover production machine has a number of 
disadvantages. By way of example, the wrapping fingers rock relatively 
rapidly around the cover board edge with the result that the overlay 
material is neither pressed flat against the leading edge nor is it held 
against the edge or the surface of the board to which the overlay is to be 
adhered. Thus, the desired, taut folding of the overlay material around 
the board edges cannot be achieved with apparatus of the type disclosed in 
U.S. Pat. No. 2,749,967, this being particularly true when employing 
overlay materials which are relatively stiff. The foregoing deficiency is, 
in large measure, attributable to the relatively small contact pressures 
exerted by the wrapping fingers. However, applying a greater pressure 
through the use of stronger spring elements would not solve the problem 
since the spring forces must be overcome by the moving cover unit and the 
possibility of damage to the overlay material increases significantly as 
the spring force which must be overcome increases. 
It is also to be noted that, in the case of a wrapping apparatus of the 
type disclosed in U.S. Pat. No. 2,749,967, the wrap-folded overlay 
material is not held firmly against the cover board for a defined period 
of time. The maintaining of pressure against the wrap-folded overlay 
material for an "initial bonding time" is an absolute necessity if 
adhesive-bonding is to be reliably achieved. The period of time during 
which the pressure must be maintained is a function of the type of 
adhesive used, the thickness of the adhesive applied and the nature of the 
overlay material and cover board being processed. The initial bonding time 
of the adhesive becomes particularly important if the production rate of 
the wrapping apparatus is increased and/or if stiff overlay materials such 
as "Balacron" or "Skivertex" are used. 
Continuing to discuss the problem of insuring reliable adhesive bonding, 
the consequence of a pressing time for the wrap-folded overlay material 
which is too short is that the overlay material will subsequently separate 
from the cover board. Any such separation is the cause of significant 
production problems, particularly during the operations which must 
subsequently be performed on the cover unit such as pulling-in the corners 
and wrapping the side edges. 
To summarize the above discussion, prior art wrapping techniques and 
apparatus as exemplified by the disclosure of U.S. Pat. No. 2,749,967 are 
incapable of achieving the sharp-edged finish that is desired in book 
cover production and such prior apparatus and techniques often result in 
air entrapment between the overlay material and the cover board, hollow 
edges and wrap separation. 
Another example of a prior art method and apparatus for use in the 
manufacture of book covers, particularly for wrapping overlay material 
around cover boards, may be seen from U.S. Pat. No. 2,667,909. In the 
apparatus of U.S. Pat. No. 2,667,909 the cover units, comprising the 
overlay material pre-bonded to the cover boards, are caused to move 
through a pair of cylindrical segments. During the course of this 
movement, the overlay material that projects beyond the cover board 
leading edge is first folded downwardly through the action of a folder 
plate installed in the upper cylindrical segment. The downwardly folded 
overlay material is caused to emerge through an aperture under the 
influence of control devices and is subsequently held in the folded 
position by the action of an air blast. The folded flap is subsequently 
pressed against the cover board as the moving cover unit passes between 
pressure rollers. In order to wrap the trailing edge of the cover unit, a 
second folder plate is installed in the upper cylindrical segment and, 
under the influence of a control device, produces the downward folding of 
the overlay material which projects beyond the trailing edge of the cover 
board. The lower cylindrical segment has a driving plate which is movable 
in the direction of travel of the cover unit. This driving plate further 
folds the overlay material and presses it firmly against the cover board 
from below until the cover unit is received between the pressure rollers. 
Apparatus of the type disclosed in U.S. Pat. No. 2,667,909 cannot achieve 
the "initial bonding time" since neither the folder plates, which are 
moved relatively rapidly past the board edges, for the pressure rollers, 
which act only briefly on the cover unit, are designed to maintain their 
pressure for an extended period of time. 
It is also to be noted that, in apparatus of the type exemplified by U.S. 
Pat. No. 2,667,909, only small push forces are exerted by the folder 
plates as they move past the cover board edges and these forces are 
insufficient to pull the overlay materials tautly around the board edges, 
this being particularly true if the overlay materials are relatively 
stiff. Similarly, this type of prior art apparatus is also incapable of 
achieving the sharp-edged finish, free of air pockets and hollow edges, 
which is desired. This is particularly true in the case of the 
leading-edge wrapping operation in which merely an air blast is used for 
holding the folded wrapping material. 
SUMMARY OF THE INVENTION 
The present invention overcomes the above briefly discussed and other 
deficiencies and disadvantages of the prior art by providing a novel and 
improved technique for the production of high quality book covers at high 
production rates. The invention also encompasses apparatus for 
implementing this novel technique wherein means are provided for folding 
upwardly the overlay material which projects beyond the leading and 
trailing edges of the cover board and subsequently further folding of this 
turned-up material over and pressing it into firm contact with the 
continuously moving cover board. This apparatus comprises cooperating 
wrapping systems for wrapping the leading and trailing edges of a cover 
unit, these wrapping systems being separated by a defined but adjustable 
distance and being propelled by drive means so as to be movable on an 
endless path. Each wrapping system comprises a wrapping rail which extends 
transversely to the direction of cover unit movement and which is 
pivotally mounted on a support member. The wrapping rails are controlled 
in a displacement-dependent mode and cooperate with an associated support 
rail to form a clamp. The wrapping rail which operates on the leading edge 
of the cover unit is actuated first, through the agency of control 
devices, to turn the overlay material extending from an incoming cover 
unit upwardly along the leading side surface of the cover board. The 
leading-edge wrapping rail moves upwardly and, once the cover unit is 
supported by the associated support rail, the leading edge wrapping rail 
is moved counter to the direction of movement of the cover unit so as to 
fold the overlay material over and to then press the folded overlay 
material firmly against the cover board. The cover unit is then held 
clamped between the leading edge wrapping rail and its associated support 
rail. The trailing-edge wrapping rail, actuated similarly through the 
agency of control devices, then folds the overlay material extending from 
the trailing edge of the cover board. The trailing edge wrapping rail 
moves upwardly and, when the cover unit is supported by the support rail 
associated with the trailing-edge wrapping rail, the trailing-edge 
wrapping rail moves in the direction of movement of the cover unit so as 
to fold the overlay material over and downwardly against the surface of 
the cover board, such folding being executed at a speed which is excess of 
the speed of movement of the cover unit. The railing-edge wrapping rail 
and its associated support rail clamp the folded-over overlay against the 
cover board until the cover unit is released by appropriately located 
control devices. 
Apparatus in accordance with the present invention achieves optimum 
stretching of the overlay material around the cover board edges and 
towards the center line of the cover unit, this stretching being achieved 
through the use of wrapping rails which move in continuous pressure 
contact, firstly with the edge surfaces of the boards and immediately 
thereafter with the face surfaces of the boards. Also, once the overlay 
material has been pulled taut, the cover unit is held during its 
continuing movement over a defined distance, i.e., the cover unit is 
clamped in a clamping gap formed by wrapping rails and support rails until 
being released for delivery to downstream transport means. 
In the operation of the present invention, during the wrapping procedure, 
hold-down elements press the cover unit against the support rails and, 
accordingly, the cover unit does not itself have to absorb the forces 
generated by the wrapping rails. Gentle treatment of the cover unit is 
guaranteed by elimination of relative movement between the cover unit and 
the surfaces on which it is supported. This permits the employment of 
relatively large folding forces and, in turn, makes it possible to use a 
wide variety of materials for the overlay. The present invention also 
makes it possible to produce high quality book covers at high repetition 
rates, even with stiff overlay materials. Moreover, by reason of the 
amount of time available for clamping, there is no need to impose special 
requirements on the adhesive and, particularly, a low-viscosity adhesive 
can be utilized in the interest of minimizing the well-known problem of 
adhesive stains.

DESCRIPTION OF THE DISCLOSED EMBODIMENTS 
With reference now to the drawing, the basic construction of the disclosed 
embodiment is believed to be best seen from FIG. 1. The function of the 
disclosed apparatus is to wrap overlay materials, which have been 
adhesively bonded to backing boards, around the leading and trailing edges 
of the backing boards in the course of producing book covers. In the 
disclosed embodiment, the apparatus comprises driven chains that move on 
endless paths and carry wrapping systems. These wrapping systems, i.e., 
the pairs of cooperating leading and trailing systems in reference to the 
direction of book cover movement, serve both to turn up the overlay 
material and to fold it around the leading and trailing edges of the 
continuously moving boards. In a typical application, and in order to 
achieve a high production rate, a total of four wrapping systems are 
preferably installed on the driven chains. In order to facilitate 
understanding of the invention, however, the description below will 
primarily refer to a single side of the wrapping apparatus, i.e., a single 
pair of wrapping systems, although it is to be understood that the 
components to be described will be present on both sides if the apparatus 
is viewed in the longitudinal direction. 
The leading-edge and trailing-edge wrapping systems are installed on 
separate chain assemblies which lie in parallel planes and which are 
continuously driven from a common drive unit, not shown. In the disclosed 
embodiment, the leading-edge wrapping systems are installed on 
outwardly-disposed chains 8 which are engaged by direction-changing 
sprockets 5, 6 and 7. The trailing-edge wrapping systems of the disclosed 
embodiment are installed on chains 12, located inwardly with respect to 
chains 8, which are engaged by direction-changing sprockets 9, 10 and 11. 
The installation of the wrapping systems on separate chain assemblies 
enables the apparatus to be adjusted to accommodate book covers of 
different size. Such adjustment is accomplished by shifting the chains 8, 
and thus the leading-edge wrapping systems, relative to the chains 12, and 
thus the trailing-edge wrapping systems, either in or counter to the chain 
running direction as appropriate. 
Each of the wrapping systems comprises a leading-edge wrapping rail 13, 
with a cooperating support rail 14, and a trailing-edge wrapping rail 13', 
which has a cooperating support rail 14'. The wrapping and support rails 
extend transversely to the direction of movement of the cover units 1, 
i.e., a backing board with an overlay sheet adhered thereto. The wrapping 
rails 13 indirectly interconnect the chains 8 and the wrapping rails 13' 
indirectly interconnect the chains 12. 
Since the construction of the leading-edge wrapping systems is essentially 
the same as that of the trailing-edge systems, the following discussion 
will be primarily directed to a leading-edge system. 
The wrapping rail 13 has a rounded working surface 13a and is tiltably 
mounted in a cross member 15. The cross member 15 is provided with arms 
15a which extend outwardly therefrom. A follower roller 16 is mounted on 
extension arm 15a and is freely rotatable. The cross member 15 is integral 
with an axle 15b having a stepped portion that is received in a support 
bearing 17. The support bearing 17, in turn, is mounted in a driving 
element 18 in a manner such that it can slide freely in the vertical 
direction. As may be seen from FIG. 3, a compression spring 19 biases the 
support bearing 17 in a first direction. 
The cross member 15, with its wrapping rail 13, is articulated to a drive 
chain 8 via driving elements 18. Further driving elements 20 are located 
immediately adjacent to the driving elements 18. The driving elements 20 
function as carriers for the support rail 14 which cooperates with the 
wrapping rail 13. The driving elements 20 are coupled to the driving 
elements 18 by means of articulated links 21 as shown in FIG. 1. 
The wrapping rail 13 and its cooperating support rail 14 define a clamping 
means which receives a rectangular region of the cover unit 1 abutting the 
leading edge of the cover unit backing board. The clamping zone or region 
is in part defined by a cover unit receiving rectangular recess 13b 
provided in the wrapping rail 13. 
A defined contact pressure for application to the clamped cover unit 1 is 
provided by a compression spring 26. Compression spring 26 extends between 
an extension 17a, formed integrally with the support bearing 17, and a 
counter-bearing 23 mounted in the wrapping rail 13. 
A control roller 28 is installed on the axle 15b of cross member 15. Roller 
28 travels along a control track 29 in the course of its orbiting 
movement. The cross member 15 can pivot about axle 15b, and the control 
roller 28 is kept in contact with the track 29 by means of the 
above-mentioned compression spring 19. 
As noted above, a driving element 18 is installed at each end of the 
wrapping rail 13. The driving elements 18 are interconnected by a 
connecting rail 27. Connecting rail 27 carries a bearing block 32 through 
which a tie rod 33 passes. The tie rod 33 is articulated to a horn 35, 
which extends from the cross member 15, and is provided with a head which 
functions as a stop. 
The follower roller 16 of the leading wrapping system is kept in contact 
with a control track 41 by means of a compression spring 36 which is 
seated on tie rod 33. The compression spring 36 extends between the 
connecting rail 27 and the horn 35 which, as noted, extends from the cross 
member 15. In the case of the trailing edge wrapping system, a follower 
roller 16' is kept in contact with a control track 37 by an analogous 
arrangement of parts. 
I order to eliminate the necessity of having the drive chains fulfill 
guidance functions, and to also ensure that the chains are subjected only 
to tension forces, the driving elements 18 are provided, at their opposite 
ends, with rollers 42. The rollers 42 travel in guide slots 43 in a 
machine frame 44 as the chains move on their endless paths. 
The cover units 1 are delivered to the apparatus of the present invention 
via a support table 45 by means of transport rollers 40. The cover units 
ejected from the rollers 40 enter the region in which the leading edge 
wrapping system operates and are held on the table 45 by an upper holding 
rail 46. Upper hold-down segments 47 are provided for applying holding 
pressure during the portion of the operating cycle in which the overlay 
material is turned up around the trailing edge of the cover board. The 
segments 47 are driven in a manner such that they rotate, touching down on 
the continuously moving cover units, in synchronism with the cover unit 
movement. The hold-down segments 47 are installed on a shaft 48, which is 
positioned by means of cantilever arms 49 mounted in the machine frame 44, 
such that they may be swung in the directions indicated by arrow 50 on 
FIG. 1. Thus, the hold-down segments can be vertically adjusted to 
accommodate different cover material thicknesses. The hold-down segments 
47 are rotated by means of a chain drive 51. 
The control tracks 29, 37 and 41 are mounted on a support body 54 and are 
vertically adjustable by means of lifting spindles 55. The lifting 
spindles 55 are supported in the machine frame and enable the distance 
between the wrapping rails 13 and 13, and their cooperating support rails 
14 and 14' to be varied so as to accommodate different cover material 
thicknesses. 
As previously mentioned, a defined contact pressure is applied to a clamped 
cover unit 1 via the action of a compression spring 26 extending between 
the extension 17a of the support bearing 17 and the counter-bearing 23 on 
the wrapping rail 13. Referring to FIGS. 6 and 7, in order to enable a 
larger force to be applied and in order to facilitate the processing of 
comparatively stiff overlay materials, the apparatus may be modified such 
that the support rails 14 press against the wrapping rails 13 under the 
action of spring elements 60. In this modified arrangement, compression 
springs of different strength can be used so as to enable the compressive 
force to be varied. Continuing to refer to FIGS. 6 and 7, the support 
rails 14 are, in the alternative embodiment, spring-mounted on a 
structural component 61 via driving elements 20, the driving elements 
acting as carriers. In the alternative embodiment, a linking lever 62 
replaces the compression springs 26. 
In order to open the clamp defined by the wrapping rail 13 and the support 
rail 14, the rail 14 is functionally connected to a control beam 63. A 
control roller 64 is installed on beam 63 and engages a cam slot 65 in 
order to cause a transverse displacement of the beam 63. The beam 63 is 
retained on the structural components 61 via pins 67 which engage 
elongated holes 66. Thus, the lowering movement of the support rail 14 is 
brought about by the transverse displacement of the control beam 63 
resulting from the beam 63 being provided with control slots 68 through 
which pins 69 extend, the pins seating in the structural component 61. 
Also in the interest of compensating for material thickness variations, the 
support rail 14 is designed to be formed by two shorter portions. 
The mode of operation of the wrapping apparatus will now be described. 
FIGS. 4a-d and 5a-d illustrate how the overlay material is wrapped around 
the cover board edges in the individual movement phases. FIGS. 4a-d relate 
to the wrapping of the leading edge of the cover board while FIGS. 5a-d 
depict the wrapping of the overlay about the trailing edge of the cover 
board. 
A cover unit 1 is guided between the support table 45 and the holding rail 
46, and enters the region in which the wrapping systems operate. As noted, 
the wrapping systems are propelled in a manner such that they continuously 
move on an endless path. In the course of this orbiting movement, the 
wrapping rail 13 of the leading-edge wrapping system first turns up the 
overlapping material 1a which projects beyond the leading edge of the 
cover board, the overlay being turned up along the leading side surface of 
the board. The foregoing procedure is produced as a result of the follower 
roller 16 and control roller 28 running onto respective control tracks 29 
and 41 and is represented in FIG. 4a. Once the leading-edge clamping zone 
of the cover unit is supported by the support rail 14, which has been 
moved to meet the cover unit, the wrapping rail 13 folds the overlaying 
material 1a back around the upper edge of the cover board as a result of a 
movement of the rail counter to the direction in which the cover unit is 
moving. The wrapping rail 13 rubs the overlaying material into contact 
with the cover board, acting in the direction towards the middle of the 
cover unit, and holds the cover unit clamp between itself and the support 
rail 14. 
The clamped cover unit 1 is now transported forwardly by the leading edge 
wrapping system and enters the region in which the trailing-edge wrapping 
system operates. The trailing-edge wrapping system is propelled in a 
manner such that it moves together with the leading-edge wrapping system, 
on the same endless path, and in the course of this orbiting movement the 
trailing edge wrapping rail 13, turns up the overlay material 1a which 
projects beyond the trailing edge of the cover board. The overlay material 
is folded upwardly along the trailing side surface of the cover board as a 
result of the control rollers 28' and follower rollers 16' running onto 
the control tracks 29 and 37. This operation is depicted in FIGS. 5a-d. 
Once the support rail 14' has been moved into position beneath the 
trailing edge clamping zone of the cover unit and the hold-down segment 47 
has engaged the cover unit, the trailing edge wrapping rail 13 folds the 
overlay material back around the upper edge of the cover board. This 
folding is a consequence of an overtaking movement of wrapping rail 13', i 
e. a movement executed at a speed in excess of that at which the cover 
unit is moved, and results in the overlay being rubbed into contact with 
the cover board in the direction of the middle of the cover unit. The 
cover unit is now also clamped between trailing edge wrapping rail 13, and 
its support rail 14'. 
The rubbing of the overlay material la into contact with the cover board 1b 
is effected in an advantageous manner, i.e., the wrapping rails 13 and 13' 
are oriented such that they are tilted toward the middle of the cover unit 
1. This results in a force component being exerted on the overlay material 
1a at an angle to the board via the rounded working surfaces 13a and 13a' 
of the wrapping rails. This inclined force component reinforces the 
rubbing-on effect discussed above which is directed toward the middle of 
the cover unit. 
The moving and partially finished cover unit 1, clamped by the leading-edge 
and trailing-edge wrapping systems, is released in the delivery area of 
the wrapping apparatus. The leading-edge wrapping system first releases 
the cover unit as a result of the control roller 28 running onto a cam 29a 
on the control track 29, this action causing the lifting of the wrapping 
rail 13. The wrapping rail 13 and support rail 14 are then moved 
downwardly over the chain direction-reversal arrangement. The cover unit, 
which is continued to be transported forwardly by the trailing-edge 
wrapping system, while being supported on a bolster rail 56 which is 
carried by the chain assembly 5, 8, arrives in the vicinity of a pair of 
transport rollers 57. The transport rollers 57, when the trailing-edge 
wrapping system defined clamp is released, engages the cover unit and 
directs it to a downstream located processing station. The release of the 
trailing-edge wrapping system results from its control roller running onto 
the cam 29a on the control track 29. 
While preferred embodiments have been shown and described, various 
modifications and substitutions may be made thereto without departing from 
the spirit and scope of the invention. Accordingly, it is to be understood 
that the present invention has been described by way of illustration and 
not limitation.