Vertical signature stacker

A vertical signature stacker comprises a separator plate supported within a stacker framework for removal of signatures from a conveyor belt and delivery thereof to a fork. The separator plate is supported by a slide frame that may be tilted and vertically adjusted. The separator plate is also adjustable in a horizontal direction. The fork receives signature stacks and is vertically adjustable. The separator plate has an upper limit stop that is generally level with the head of an operator.

BACKGROUND OF THE INVENTION 
This invention relates to an improved vertical signature stacker. This type 
of stacker is already widely known, as evidenced, for example, by U.S. 
Pat. No. 3,969,993. Essentially, these vertical stackers comprise a 
stacker framework, conveyor belts for supporting the signatures delivered 
by a rotary press, an outer separator plate designed to interrupt the 
continuous flow of incoming signatures and form the initial part of the 
stack, translation guides and powered units designed to raise and lower 
the separator plate, a fork onto which the stacks delivered by the 
separator plate are placed, said fork being supplied with translation 
guides and with powered units governing the upward and downward motion of 
same, a sliding wall for lowering the stacks and a bottom wall for 
supporting the stacks so formed, said sliding and bottom walls being 
provided in the form of roller boards. 
The separator plate, with the relevant jack controlling the forward and 
reverse motion of same, is hinged onto an outer support located in the 
upper front section of the stackers and, more specifically, in such a way 
that when the plate reaches its bottom limit stop position, it is roughly 
equal in height to the stacker operator. This design entails a number of 
shortcomings and disadvantages, the most serious of which shall be 
referred to hereinafter. At the end of its downstroke, the separator plate 
reaches a height where it is roughly level with the head of the operator; 
after reaching this position, the plate is tilted upwards, and the 
upstroke is effected. Besides causing considerable inconvenience, these 
movements may prove a serious hazard to the operator's safety. In 
addition, as the separator plate runs along a plane which cuts across the 
middle of the stacker, the operator tends to stand either to the right or 
to the left of the stacker, which makes it somewhat more difficult to 
follow closely all the steps involved in the stacking process. Since the 
strokes of the separator plates normally measure approximately 40 cms and 
the height of the plate in its lowermost position ranges from 180 to 190 
cms, it readily follows that the overall height of the stackers adds up to 
roughly 220-230 cms. This design, therefore, implies significant 
additional construction costs and, furthermore, fails to take into account 
some basic operative requirements, in that the operator must virtually 
"climb" up the stacker in order to gain access to the upper section 
thereof and to adjust and line up the upper stacking positioners. 
Moreover, the higher the construction, the greater the length of the 
signature conveyor belts required for its operation; this, in turn, means 
that more powerful equipment must be used in order to drive said belts and 
that expensive, tailor-made guide pulleys must be employed. A further 
disadvantage inherent in these exceedingly high stackers is that the 
relevant conveyor belt paths feature a steeply sloping section, which 
often results in undesired slippage or overlapping of signatures, e.g. 
where coated paper is used. 
Conventional vertical stackers present other shortcomings, in that both the 
separator plate and the fork are operated by a single electric motor 
featuring a dual friction clutch as regards the downstrokes of the plate 
and fork, whereas the upstrokes of same are effected by means of pneumatic 
cylinder-ram units. The fork-driving pneumatic cylinder-ram unit also acts 
as a braking device when the stack is lowered at considerable speed after 
its completion. In addition to the fact that these pneumatic units entail 
substantial costs, it is worth noting that said pneumatic braking devices 
are rather difficult to calibrate, for the stacks, while lowered from one 
and the same height, may vary in weight depending on the degree of 
compactness of the relevant signatures. These pneumatic units are 
furthermore ineffective in interrupting or reducing the speed of the 
downstroke of the fork, while this would be desirable in the extreme in 
order to ensure proper automatic loading of the endboards which are 
normally placed at the upper ends of the stacks. 
While conventional vertical stackers feature a steeply sloping conveyance 
section, they may sometimes require a relatively long conveyance path in 
order to avoid the exceedingly steep slopes which may result from direct 
connection to the rotary press, as these would pose additional 
difficulties in terms of an even conveyance of the scaled stream of 
signatures. This necessarily implies a considerable overall width, while 
printing shops are normally rather small in size and therefore require a 
most efficient use of the space available. The adoption of bulky 
equipment, such as the stackers described hereinabove, may sometimes 
require additional work in order to accommodate the equipment itself in 
the existing facilities. 
SUMMARY OF THE INVENTION 
The main object of this invention is to provide an improved vertical 
signature stacker, designed in such a way as to avoid the drawback 
inherent in conventional stackers--wherein the downstroke limit stop of 
the separator plate is roughly level with the head of the operator--while 
featuring reduced overall dimensions and offering an effective solution to 
the structural and functional shortcomings referred to earlier. 
A further object of this invention is to provide a vertical stacker 
offering the possibility to interrupt temporarily the quick downstroke of 
the fork so that the upper endboards may be placed onto the stacks 
automatically. 
Yet another object of this invention is to provide a stacker constructed in 
such a way as to enable the operator to readily gain access to each and 
every part or section thereof, in order to simplify and speed up the 
adjustment of the positioning devices located in the upper part of the 
stacker and, therefore, enable the operator to perform these functions 
without undue effort or inconvenience and furthermore check the stacker 
for correct operation while retaining a central, i.e. symmetrical, 
position with respect to the stacker itself. In the device according to 
the invention, in fact, the upper limit stop of the separator plate is 
roughly level with the head of the operator, hence the latter is in the 
position to take any remedial action which may be required in the initial 
stage of stacking. Yet another object of the improved stacker according to 
this invention is to provide a substantially horizontal 
signature-conveying path taking up an extremely limited amount of space. 
This design ensures greater effectiveness and a more uniform conveyance of 
the signatures. 
These objects are achieved according to the invention with a vertical 
signature stacker comprising: 
a stacker framework 2; 
a belt-driven conveyance path for the signatures delivered by a rotary 
press; 
a separator plate 17 designed to interrupt the flow of signatures and form 
the initial part of each stack 16; 
translation guides 26 and driving units 26c designed to raise and lower the 
separator plate 17; 
a fork 8 onto which the bundles 16 delivered by the separator plate are 
placed, said fork being equipped with translation guides 7, 7a, 7b and 
with driving units designed to raise and lower same; 
a sliding wall 14 for lowering the stacks 16 and a stack-supporting wall 
15, both of which are made up of a number of rollers; 
wherein the separator plate 17 is designed to rest on a sliding frame 19 
within the framework 2 of the stacker, said sliding frame being supported 
by a powered cursor 18 through a floating connection whereby the frame may 
be tilted up and down, said frame 19 being furthermore connected to 
translation guides 26 designed to control the upstrokes and downstrokes of 
the separator plate, the upper limit stop position of the latter being 
roughly level with the head of the operator, wherein furthermore the 
abovementioned units 26c, 9 designed to drive respectively the separator 
plate 17 and the fork 8 are preferably independent and conceived as 
reversing electric motors. 
According to the invention, the sliding frame 19 of the separator plate 17 
comprises two slide bars 21 featuring a cursor 18 in the form of two 
sleeves 22 connected to each other by a plate-supporting cross member 23, 
and said frame 19 is furthermore connected to a cylinder-ram unit 24 
driving the plate 17 back and forth, the piston rod of said unit 24 being 
connected to said cursor 18. 
A cylinder-ram unit 28 is desirably interposed between the sliding frame 19 
of the plate 17, hinged through 27 onto the plate-raising and lowering 
cursor 25, and said cursor 25, said unit 28 being designed to control the 
vertical tilting motion of said plate-supporting sliding frame 19. 
According to the invention, when retracted, the separator plate 17 is 
entirely housed in the body of the stacker, i.e. does not project 
therefrom. 
Moreover, according to the invention, the translation guides 26 designed to 
control the upward and downward motion of the separator plate 17 comprise 
two channel sections housing the sliding cursor 25 which in turn supports 
the aforementioned frame 19, said cursor 25 being driven by means of 
lateral chains 26a provided with gears at their respective ends and in 
turn driven by means of other chains running within said channel sections 
and powered by an independent, preferably D.C., reversing electric motor. 
Preferably, the lateral chains 7b controlling the motion of the fork 8 are 
driven by an independent, desirably D.C., reversing electric motor. 
According to the invention, the jogging 33, pressing 34 and 
flow-interrupting units are housed within rear side panels 5, fitted onto 
the sides 3 of the stacker, said rear panels 5 defining a housing for the 
electric control board of the stacker. 
According to the invention, the path 32 defined by the signature-conveying 
belts in the rear side panels 5 is desirably horizontal. 
Moreover, according to the invention, the rear portion of said projecting 
side panels 5 features a vertically tilting connection path 31, the 
inclination of which may be adjusted depending on the relative height of 
the rotary press outlet. 
Advantageously, the motor 9 which controls the quick descent of the stack 
co-operates with a known electric component, through which the stroke of 
the fork 8 may be interrupted temporarily, in order to enable the operator 
to place the upper endboard onto the stack 16. 
With the improved stacker developed in accordance with this invention, 
several different advantages are achieved, as noted hereinafter. 
The operation of the stacker may be checked from a more comfortable central 
position, and the separator plate is always within reach even when in its 
upper limit stop position. This enables the operator to perform all the 
necessary operations, such as the adjustment and line-up of the top-end 
positioners, both more quickly and more accurately. 
The separator plate is disposed inside the stacker in order to prevent 
accidental injury, hence the operator may perform all the relevant 
functions with a higher degree of safety. Both the height of the stacker 
and the length of the horizontal signature-conveying belts have been 
reduced considerably; as a result, the stacker according to the invention 
features limited overall dimensions. This, in turn, implies significant 
structural and functional advantages. For instance, the side panels of the 
stacker may be obtained directly from steel plates produced in standard 
sizes and, therefore, with a limited amount of off-cuts. The side panels 
provided to support the signature-conveying path may be designed as 
projecting members, to be mounted onto the framework of the stacker. This 
offers an additional advantage, in that a housing for the electric 
switchboard of the stacker is obtained in the space provided under said 
projecting side panels. This feature is of considerable importance because 
it offers the possibility of placing the switchboard in a suitable, 
readily accessible location without adding to the overall dimensions of 
the stacker. Moreover, as the switchboard is independent of the stacker, 
it is not subject to mechanical vibrations, which might otherwise damage 
the more delicate electronic components through which the stacker is 
controlled. 
The total cost of the stacker is further reduced by eliminating the 
pneumatic cylinder-ram units. Indeed, the adoption of independent, 
reversing electric motors for the separator plate and the fork simplifies 
the various steps involved in the operating cycle and, as regards the 
fork-driving motor, ensures greater safety when lowering the stacks 
because braking is effected by the electric motor itself rather than by a 
pneumatic unit. Where the upper endboards are to be placed automatically 
onto the stacks, an electric motor is undoubtedly the most effective means 
to readily interrupt the quick downstroke of the fork and, therefore, 
bring it to a halt. 
The signature conveyance path is made considerably shorter as the outlet 
through which the signatures are delivered and placed onto the separator 
plate is set at approximately the same height as the outlet of the 
traditional rotary presses. This offers an additional advantage, in that 
the conveyance path is at all times level, whereas conventional vertical 
stackers include a steeply-sloping section which, as noted earlier, 
affects the signatures undesirably. 
The stackers designed in accordance with this invention are easy to 
construct, and the type of equipment used to control the motion of 
translation of the separator plate is traditional and extremely dependable 
.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
With reference to the above Figures, reproduced to different scales, 
wherein each component is marked by a specific reference number, the 
improved stacker according to the invention is indicated, in its entirety, 
at 1. Said stacker 1 comprises a framework 2 featuring two side panels 3, 
which are joined to each other by a bedplate 4 and by a number of 
crosspieces (not illustrated herein). The framework 2 further comprises 
rear side panels 5, which are mounted as projecting members onto side 
panels 3, e.g. by means of screws 6. Said rear side panels 5 are designed 
to support the signature-conveying path (not shown), in correspondence 
with the relevant signature-handling components, as described more 
specifically hereinafter. The translation guides of fork 8 are marked 7. 
Said guides may be constructed in accordance with a conventional design, 
e.g. comprising channel sections 7a housing lateral chains 7b supporting a 
cursor 8a, fork 8 resting on said cursor 8a. The upward and downward 
motion of fork 8 is effected by means of an independent reversing electric 
motor 9, desirably a D.C. motor, which, through gearing 10, drives the 
bottom geared wheels 11 of said lateral traversing chains 7b. The sliding 
wall through which the stacks 16 are lowered and the bottom wall 
supporting said stacks are marked 14 and 15 respectively, both walls being 
made up of a set of adjacent rollers. In this particular illustration, 
roller board 14 is positioned in such a way as to form a 20.degree. angle 
with the vertical. 
The separator plate, which is only sketched out in the drawings, is 
indicated at 17. The plate is supported within the framework 2 of the 
stacker and is secured to the cursor 18 of the plate sliding frame marked 
19. Said frame may comprise, for instance, an actual frame-like structure 
20 and two slide bars 21. Said cursor 18 is made up of two sliding sleeves 
22, running on bars 21 and connected to each other by a crosspiece 23 
which in turn carries the separator plate 17, said plate being 
interchangeable in the preferred embodiment. Cursor 18 is connected to the 
free end of the piston rod 24a (no detailed view thereof being provided in 
the drawings) of the cylinder-ram unit 24 controlling the forward and 
reverse motion of separator plate 17 and fixed to said sliding frame 19. 
The stroke of the piston rod 24a is desirably adjustable as a function of 
the signatures that are to be treated. The sliding frame 19 is connected 
to cursor 25 running on guides 26 fitted inside said framework 2 and 
specially designed to control the upstrokes and downstrokes of the 
separator plate 17. Said guides 26 may be channel-shaped, like the guides 
7a referred to earlier herein, and be designed in such a way as to house 
the chains 26a supporting cursor 25 and driven, through an intervening 
chain 26b, by a reversing, preferably D.C., electric motor 26c. Similarly, 
cursor 25 may feature outer guide sleeves running on corresponding guide 
bars (not shown herein). In this particular illustration, the connection 
between said cursor 25 and said slide frame 19 is effected by means of two 
coaxial hinge pins 27. The relevant drawing also features a cylinder-ram 
unit 28 interposed between cursor 25 and slide frame 19, said unit 28 
being hinged onto cursor 25 through 29 and onto slide frame 19 through 30. 
The slide frame 19, hence the separator plate 17, are desirably hinged 
onto said cursor 25, in order to enable said plate 17 to tilt upwards 
during its forward motion and to tilt downwards when disposed, at some 
distance, above the stack placed on the descending fork. The translation 
of the plate between its two limit stop positions, which are parallel to 
one another, thus occurs through a compound motion, said translation being 
linear or, desirably, curvilinear, depending on the size of the signatures 
or on the constructive parameters selected in each specific case. Said 
compound motion is designed to avoid any possible impact of the tip of the 
separator plate against the upper part of the stack which has previously 
been placed onto the fork 8. Said motion may be achieved by combining the 
motions of the two cylinder-ram units 24 and 28, or, alternatively, 
through the interposition of a positioning cam co-operating with separator 
plate 17. The profile and exact location of said cam are to be determined 
in accordance with one's specific requirements. The desired motion of 
translation of the separator plate may also be achieved through a driving 
cam alone, namely without employing the cylinder-ram unit 28; in this 
case, however, it would be more difficult to attain the required degree of 
accuracy in the repetition of the compound movements. The drawings readily 
show that when the separator plate is in its upper limit stop position, 
i.e. the position wherein it is ready to perform the interruption of the 
flow of signatures, the plate itself is housed entirely within the body of 
the stacker; the dotted lines refer to the plate in its tilted-up 
position, namely the position wherein the plate is ready to start a new 
stack. 
The signature conveyance path is roughly horizontal and, in this particular 
instance, made up of a number of conveyor belts 31; the path itself can be 
tilted up or down, position A corresponding to the outlet of the higher 
rotary presses, and position B being roughly level with the outlet of the 
lower rotary presses. The section of the signature-conveying path located 
inside the stacker is marked 32, said section featuring a jogging unit 33, 
a pressing unit 34 as well as a third unit (only sketched out in the 
drawing) specially designed to interrupt the flow of signatures and 
thereby enable the separator plate 17 to perform its function effectively. 
Section 32 of the conveyance path is followed by section 35, which leads 
to the signature delivery outlet 36. Section 35 is slightly slanted 
because it must be at right angles with roller board 14. The drawing 
clearly shows that the signature path is essentially horizontal and does 
not feature the steeply-sloping section which is typically found in 
conventional vertical stackers equipped with an outwardly-projecting 
separator plate. The signature-conveying path is driven by a separate 
motor 37, of a known type. The unit defining the upper signature-conveying 
path is marked 38. 
In the stacker according to the invention, the various steps involved in 
the operating cycle--preliminary stacking, translation of the preliminary 
stack from the separator plate to the fork, completion of the stack and 
quick descent of the stack onto the supporting roller board--are performed 
in the same way as they normally are in conventional vertical stackers 
featuring an outwardly-projecting separator plate. 
From the above description it is readily apparent that with the stacker 
according to the invention the objects and advantages referred to 
hereintofore are effectively achieved. In particular, the operator is able 
to perform the required supervisory functions in a simpler, more effective 
way, as all parts of the stacker are readily accessible and its 
construction is less bulky as compared with that of conventional stackers. 
This also means that the assembled stackers can be transported more 
easily: the design features an essentially horizontal signature conveyance 
path while offering simple, highly reliable means to interrupt the quick 
descent of the stack-carrying fork so that the upper endboards may be 
placed automatically onto the finished stacks during the downward 
translation thereof. 
Moreover, construction costs are reduced considerably, and the operations 
required in order to stretch the conveyor belts are simplified. As a 
result of lesser wear, belt rupture is less likely to occur. Similarly, 
stacker operation is more reliable. In addition, a housing for the 
relevant electric switchboard is conveniently defined in the area located 
below the rear panels of the stacker. Practically all the components may 
be replaced with other technically and/or functionally equivalent ones, 
without exceeding the scope of this invention. 
For instance, the design of the slide frame, of the relevant vertical 
guides, or of the separator plate-supporting member may be changed or 
modified without exceeding the boundaries defining the scope of the 
invention. 
All of the features contained in the description, claims and drawings are 
to be considered substantial to this invention, both singly and in any 
combination thereof.