Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to a stacking device for shipments of
envelopes and similar flat, flexible, conveyable objects.
Stacking devices of this kind are known, for example, from United
States Patent 3,152,701 Weiland, October 13, 1964, and French Patent 1,297,
063 Rehm, May 14, 1962.
In such stacking devices, care must be taken to ensure that the
rear edge of the last object fed to the stack and there brought to rest,
moves as quickly as possible out of the way of the next object, so that it is
not stuck thereby, thus causing a breakdown. From French Patent 1,297,063 it
is known to effect this by arranging a rotating centrifugal roller, equipped
with resilient bristles or flexible tabs, on the side of the stack facing the
guide wall, at the outlet of the feed-conveyor section. At least when long
envelopes are being stacked, the rear ends thereof are acted upon by the
bristles or tabs, whereby the envelopes are pivoted out of the feed path into
the required direction.
It has been found, however, that proper stacking and the building of
a neat stack cannot in all cases be achieved, even when the centrifugal roller
described above is used. This applies particularly when the stack and the
feed-conveyor section are spatially oriented in such a manner that the
objects are fed to the stack on edge, in the direction of the long edges, and
when they rest, in the stack, upon a substantially horizontal support surface
which may be in the form of a driven recessed bottom conveyor. Since the
centrifugal roller acts upon the objects for only a very short time, there is
a tendency, because of the friction between the support surface (the conveyor)
and the edges of the objects, for the rear ends, especially those of long
objects having little rigidity, to maintain the original acute angle in re-
lation to the correct attitude in the stack. This causes unwanted, trouble-
some, fanning-out of the end of the stack.
Trouble may also be caused during stacking by the objects bouncing
back to a greater or lesser degree after the leading edges thereof have come
up against the guide wall. This causes the ends of long objects to project
out of the stack or to be bent backwards. This may impede further processing
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of the stack, e.g. re-separating into an intermediate stacker.
It is the purpose of the invention to provide an improved stacking
device whereinJ regardless of the spatial orientation of the stack and of
the feed-conveyor section, satisfactory stacking can be achieved, even in
the case of long, flexible objects.
The present invention provides a stacking device for forming a
stack of flat, flexible, conveyable objects of various lengths fed in a path
through a feed conveyor device outlet in such a manner that they strike the
last object in the stack at an acute angle and then abut a lateral guide
wall which is operative to align the leading edges of said objects as they
are delivered to said stack, said stacking device including deflector means
comprising a deflector conveyor ~elt positioned in the vicinity of the end
of the stack, said deflector conveyor belt extending between two deflecting
rollers, being driven towards the front of the stack and adapted to act upon
the trailing edges of objects delivered to said stack, said deflector con-
veyor belt having a minimum spacing from the guide wall corresponding
approximately to the length of the longest object to be stacked.
If the feed-conveyor is in the form of two conveyor belts carrying
the objects between them, in one preferred embodiment a section of the
conveyor belt running over deflecting rollers at the end of the stack serves
as the deflector conveyor belt.
Various possible configurations of stacking device are described
in greater detail hereinafter, by way of example only, in conjunction with
the accompanying drawings, wherein:
Figure 1 is a diagrammatic plan view of a first embodiment of a
stationarily arranged stacking device in accordance with the invention.
Figure 2 is a diagrammatic plan view of a second embodiment of a
stacking device of this kind; and
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Figure 3 shows another embo~;ment, in which the stacking device
is arranged upon a mobile carriage as a component of an intermediate stacker.
In all of the embodiments illustrated in the drawings, the
support surface for the stack is recessed lower belt 3 running over roller
1, 2~ the belt projecting through an appropriate gap in a baseplate 4.
In the case of the stacking devices in Figures 1 and 2~ the
belt 3 is moved towards the left, in known fashion, by a drive means (not
shown) as the stack 5 grows. A support plate 6 is provided at the front of
the stack~ the said plate being mcunted upon a slide 7 running parallel with
the belt 3~ the plate 6 being adapted to move longitudinally upon, and to
pivot about, the slide. In its operative position, the support plate 6 rests
upon the belt 3 and is therefore carried along to the left therewith, as is
the stack 5. For the purpose of removing a part of the stack without
interrupting the stacking operation~ ~lpport plate 6 may be raised by means
of handle 8, moved to the right on the slide 7 and re-inserted into the
stack at any desired location.
In Figure 1, the conveyor used to feed the objects is a covered-
belt conveyor in which the objects are carried along between two conveyor
belts 9~ 10 which are in contacting relationship. Conveyor belt 9 runs over
rollers 11~ 12, 13~ 14 and conveyor belt 10 runs over rollers 15~ 16~ 17~ 18
19~ of which rollers 11 and 15 are driven. Roller 19 is located immediately
adjacent the end of the stack and thus acts as a stacking roller.
Alignment of the front edges of the objects, which are fed at a
relatively high speed, is achieved by means of a guide wall 20 in the form
of a batten which, in the embodiment illustrated, extends over the entire
effective length of belt 3.
The details of the stacking device described up to this point are
known. In known devices, deflecting roller 13 is also designed as a
centrifugal roller, the method of operation of which was described at the
F~nch Patent 1~ ~97, "(0~
beginning hereof with reference to Ccrman Public Inspcction Tcxt 1 113 182.
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In the embodiment iIlustrated in Figure 1, an additional element
is provided in the vicinity of the end of the stack, namely an aligning
belt 21 which, in this case, is in the form of a separate endless conveyor
belt. Belt 21 passes over an additional deflecting roller 22 and - above
conveyor belt 9 - around deflecting roller 13, by means of which it is
driven towards the front of the stack. The shortest distance between belt
21 and guide wall 20 corresponds approximately to the length of the longest
object to be stacked by the stacking device.
Deflecting roller 22 is arranged advantageously in relation to
deflecting roller 13 in a manner such that the distance between aligning
belt 21 and guide wall 20 increases towards the front of the stack.
Driven aligning belt 21 applies to the rear edges of long objects
a force acting towards the beginning of the stack. This force may be in the
form of direct mechanical transportation, or it may be achieved by aerodynamic
means. A strong mechanical transportation force is applied especially to the
rear edges of any objects which rebound sharply when their front edges strike
guide wall 20. The use of the aligning belt also allows the device to operate
reliably, even when long, flexible objects are being stacked, thus ensuring
the building of an orderly stack.
The embodiment illustrated in Figure 2 differs from that explained
in Figure 1 in that the aligning belt is no longer a separate endless con-
veyor belt, but is a part 9~ of conveyor belt 9 running over deflecting
rollers 13 and 22, i.e. of the covered conveyor belt running to the end of the
stack. Thus the desired object is achieved, without ueing an additional
element, but merely by altering the path of travel of one conveyor belt.
In the embo~;ment illustrated in Figure 3~ the stacking device
is arranged upon the mobile carria e 23 of an intermediate stacker, such as
~ n,tel S~t~s ~le~t 3,ls~q~1
that disclosed in 6crYntt~4r~wn~-~ 101 29~. Located at the front the stack,
not shown here, is a separator 24. Underground belt 3 is driven only when
objects are removed by the said separator. Adaptation to the length of the
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stack is obtained by displacing the carriage 23.
The conveyor section feeding the objects consists of two conveyor
belts 29 and 30, some of which pass over ~stationary~ rollers 11, 12, 25 and
15, 26, 27, and some over "mobile" rollers (i.e. rollers arranged on carriage
23) 131, 22 and 14 and 16, 17, 18, 19 and 28 respectively.
In Figure 3, in addition to the use of aligning belt 29', deflect-
ing roller 13' is designed, in a manner known per se, as a centrifugal
roller, being provided above and below the conveyor belt 29 with resilient
bristles 13" or the like elements. It has been found that the centrifugal
roller and the aligning belt complement each otherls function in a particular-
ly advantageous manner. It is to be understood that other embodiments of the
invention, for example those illustrated in Figuresl and 2, may also be
complemented by the addition of a centrifugal roller.
Apart from the differences described above, the method of operation
of the stacking device illustrated in Figure 3 is the same as that of the
device illustrated in Figure 2.
