Apparatus for handling of flat goods

Flat goods such as sheets of cardboard are destacked or removed from a stack for the purpose of further processing, especially in stamping, cutting, or break-out devices. A carrier is introduced into the stack. The carrier has a surface which remains stationary relative to that portion of the stack which is being removed when the carrier is withdrawn from the stack. For this purpose the carrier which is supported in a frame, is provided with a surface which is movable relative to the carrier. The movable surface is guided at least around the leading edge of the carrier.

BACKGROUND OF THE INVENTION 
The present invention relates to an apparatus for destacking or removing 
sheet-like flat goods from a stack such as a stack of cardboard sheets or 
the like. The invention is especially suitable for cooperation with 
stamping, cutting or break-out devices. 
Flat goods such as paper or cardboard sheets in their already stamped 
condition or in the initial, unstamped condition, are usually stored and 
transported in stacks and it becomes frequently necessary to destack such 
materials for further processing. Such destacking is necessary, for 
example, for removing individual sheets or layers from a stack and also 
for the purpose of making partial stacks, whereby each partial stack 
comprises several individual layers. 
It is known to use fork-lifts, for example, for destacking work. However, 
the insertion of the fork frequently causes damage to the stacked material 
which is undesirable especially where each sheet of a stack itself is 
already expensive, for example, such as sheets of panelling and the like. 
It has been found that the damage results from the fact that the fork or 
the carrier has a surface which moves relative to the stack portion being 
removed as the fork or carrier is inserted into the stack. 
OBJECTS OF THE INVENTION 
In view of the foregoing, it is the aim of the invention to achieve the 
following objects, singly or in combination: 
to provide an apparatus for destacking sheet goods by means of which it is 
possible to remove single sheets or a plurality of sheets from a stack in 
a gentle manner, whereby the sheets will not be damaged; 
to provide an apparatus which is capable to remove a plurality of smaller 
stacks from a larger stack of sheet goods without damaging any of the 
sheets in any of the stacks; and 
to provide the carrier with a flexible belt surface secured in such a 
manner that the belt may remain relatively stationary with regard to the 
stack portion being removed while being movable relative to the carrier. 
SUMMARY OF THE INVENTION 
The apparatus of the invention operates by first pushing a carrier into a 
stack whereby the surface of the carrier remains stationary at least 
relative to the stacked portion to be removed. Thereafter, the lifted 
stack portion on the carrier is removed, whereby this may be accomplished 
either directly with the carrier or by displacing a partial stack on the 
carrier. 
The apparatus according to the invention is characterized in that a 
flexible cover member forms at least a portion of the surface of the 
shiftable carrier and that the flexible cover member is guided around the 
leading edge of the carrier which penetrates into a stack, whereby the 
flexible cover member is also movable relative to the carrier. Preferably, 
the flexible cover member is a belt or it comprises a plurality of louvers 
interconnected to form a belt type structure. One end of the belt is 
rigidly connected to a portion of the apparatus, whereas the other end of 
the belt is arranged so that the belt may yield, whereby the cover portion 
of the belt may come to rest on the carrier when the latter is pushed into 
a stack. Thus, a relative motion between the cover portion of the belt and 
the stack portion to be removed is avoided.

DETAILED DESCRIPTION OF PREFERRED EXAMPLE EMBODIMENTS 
FIG. 1 illustrates an apparatus 1 according to the invention for destacking 
of sheet or panel type goods or for the removal of a partial stack 2 from 
a larger stack 3. The apparatus comprises a carrier 4 which is supported 
in the machine frame 5 for lateral displacement into the stack 3. The 
machine frame 5 comprises vertical, upright supporting posts 6 and 7 as 
well as 8 and 9, please see FIG. 5. The uprights are operatively 
interconnected by rigid horizontal frame members 10 and 11 to form the 
rigid frame 5, for example, by welding or the like. The carrier 4 is 
horizontally displaceable in the machine frame 5. For this purpose there 
are provided two guide rods 12 and 13 on which the carrier 4 may be 
displaced on rollers 14 and 15 as well as 16 and 17. One pair of rollers 
or runners 14 and 16 is pivotally secured to the carrier 4 by means of 
tilting arms 19 and 20 in such a manner that the carrier 4 in its 
withdrawn position shown in FIG. 1 is able to be tilted upwardly with its 
rear end or edge 21. This pair of rollers 14 and 16, as compared to the 
pair of rollers 15 and 17 is more remote from the forward edge 18 of the 
carrier 4 by means of which the carrier 4 enters into the stack 3. The 
carrier 4 as described above, forms with its rollers 14, 15 and 16, 17, a 
carriage which is displaceable by means of a chain drive comprising two 
endless rotating chains 22 arranged alongside the carrier 4 and two 
further revolving chains 23 and 24 driven by a motor 25. 
The two runs of the chains 22 extend in parallel to the guide rod 12 and 
run over gear wheels 26, 27 which are arranged laterally outside the 
carrier 4. Cam means 28 are secured to one run of the chain 22, preferably 
the upper run. The cam means 28 engage the carrier 4 for shifting the 
latter back and forth in accordance with the movement of the chains 22. 
According to the invention a cover member 29 extends around the leading or 
forward edge 18 of the carrier 4. The cover member 29 is guided around the 
forward edge 18 and has a width corresponding substantially to that of the 
carrier 4. In the alternative the cover member 29 may be somewhat narrower 
than the carrier 4. The cover member 29 may be a flexible belt or it may 
be constructed in the form of blinds from a plurality of rods or the like. 
As illustrated in the drawings, the shown example for the cover member 29 
is a flexible belt which may be wound up on a roller. 
One end 30 of the belt cover member 29 is rigidly connected to the machine 
structure. The other end 31 is yieldably secured as will be described in 
more detail below. The rigid end 30 is secured to a table top 32 which may 
be lifted above the level of the carrier 4 by means of a piston cylinder 
arrangement 33, preferably of the hydraulic kind. The arrangement is such, 
that the cover member 29 may be brought exactly to the level of the 
carrier 4 so that the cover member 29 is aligned with the carrier 4, 
whereby the cover member 29 extends substantially coextensively with the 
carrier 4 in which position the cover member 29 may be lowered with the 
carrier 4. Brackets 34 and 35, best seen in FIG. 4 connect the piston rods 
36 of the hydraulic piston cylinder devices 33 with the table top 32. 
The second yieldingly secured end 31 of the belt cover member 29 may be 
wound onto the roller 37 as mentioned above. The roller 37 has a tendency 
to keep the cover member 21 tight under the influence of a return spring 
not shown which acts in the same manner as self returning window blinds. A 
belt brake 38 is operatively connected to the belt cover member 29 and 
also to the motor 39 which thus makes sure that the belt cover member 29 
is always kept under a high bias tensioning. The leading edge 18 of the 
carrier 4 comprises a guide roller 40 and the cover member 29 leads around 
this guide roller 40. Further, two separator wedges 41, 42 are arranged 
adjacent the outer ends of the leading edge 18 and the roller 14 for the 
cover member 29. The wedges 41, 42 make sure that the cover member 29 runs 
properly around the leading edge of the carrier 4. 
In the starting position shown in FIG. 1, the carrier 4 has been moved all 
the way to the left and the table top 32 is shown in its lifted position. 
The cover member 29 covers most of the table top 32 and extends from the 
leading edge of the table of 32 to the edge 18 of the cover member 29. 
From the edge 18 the belt cover member 29 runs over the guide roller 43 to 
the take up roller 37 located underneath the carrier 4. As the carrier 4 
is moved to the right into the stack 3 as shown in FIGS. 2 and 3, the 
cover member 29 hugs the top and bottom surfaces of the carrier 4 as may 
be best seen by comparing FIGS. 1 and 3. During this motion of the carrier 
4, the cove member 29 remains stationary relative to the underside of the 
stack portion 2 which is to be lifted. This is so because the cover member 
29 is rigidly secured with its rear edge or end 30 to the table top 32. A 
relative motion takes place only between the carrier 4 and the top portion 
44 as well as the bottom portion 45 of the cover member 29. This relative 
motion between the carrier 4 and the cover member 29 continues until the 
carrier 4 reaches the position shown in FIG. 3. 
The apparatus 1 according to the invention further comprises a holding and 
pushing mechanism for removing a lifted sheet or stack portion from the 
top of the carrier 4 as best seen, for example, in FIG. 6. The apparatus 
46 comprises a pusher member 47 which is secured to two drive members 48 
and 49 as seen in FIGS. 1 and 5. More specifically, the pusher member 47 
is secured in an exchangeable or replaceable manner to a support member 50 
which in turn is secured through journal bearings 51 shown in FIG. 1. As 
shown in FIGS. 1, 2, and 3 a counter-weight 52 is also operatively secured 
to the support member 50 whereby the pusher member 47 may be held in a 
lifted position, in other words, in an upwardly tilted position with the 
counter-weight 52 pointing downwardly. The lifting is accomplished by 
moving the counter-weight 52 in the direction of the arrow 52' as shown in 
FIG. 6. 
The two drive members 48 and 49 are supported in a displaceable manner on 
guide rods 53 and 54 extending in parallel to the movement direction of 
the carrier 4. Further, a spindle drive comprising the spindles 55 and 56 
is operatively connected for displacing the drive members 48, 49 and thus 
the pusher member 47. The two spindles 55 and 56 are supported by the 
upright post 6, 7, 8, and 9 and carry at their ends bevel gears 57 and 58 
cooperating with respective bevel gears secured to drive shafts 59 and 60 
driven by a motor 61. When the motor 61 is energized, the spindles 55 and 
56 are rotated and thus displace the pusher 47 through the drive members 
48 and 49. 
The stack 3 rests on a stacking table 62 which is adjustable in its 
elevational position by means of guide rods 63, 64 in the machine frame 5. 
Further, the stacking table 62 is suspended by chains 65 and 66. A total 
of four such chains 65 and 66 cooperate with chain drive sprocket wheels 
67 and 68 which are driven in synchronism with each other by a common 
motor not shown since such drives are well known in the art. 
The present apparatus operates as follows. In order to destack individual 
sheets or panels or a portion of a larger stack, the stacking table 62 is 
first elevated to the desired level so that a predetermined number of 
layers or sheets or panels of the goods to be destacked will be located 
above the elevation of the carrier 4. FIG. 1 illustrates this situation. 
The elevation of the stacking table 2 may be adjusted in very fine steps 
so as to control the number of sheets or the like to be removed from the 
larger stack. 
After the stacking table 62 has been brought into the desired elevated 
position, the holding and shifting device 46 is brought into a position in 
contact against the partial stack 2 to be removed from the larger stack 3 
as shown in FIGS. 2 and 3. Thereafter the carrier 4 is shifted 
horizontally by means of the chains 22 toward the stack 3 and into the 
stack 3 until the partial stack 2 is completely located on the carrier 4 
or rather, on the cover member 29 as shown in FIG. 3. 
Immediately upon the contacting of the leading edge 18 of the carrier 4 
with the stack 3, the latter is lowered by a distance corresponding 
substantially to the thickness of the carrier 4 in the cover member 29. 
The control for this lowering of the stack 3 is accomplished by means of 
photocells 69, 70 which are secured at the outer edges of the carrier 4 
adjacent to the leading edge 18 of the carrier 4. The photocells control 
the drive means for the stacking table 62. The stack 3 is further lowered 
when the partial stack 2 is about one half on the carrier 4 as shown in 
FIG. 2. This second lowering of the stack 3 is also controlled by a 
further set of photocells 71, 72 which are located about at the elevation 
of the rear running rollers 14 and 16. 
When the carrier 4 has reached its most forward position as shown in FIG. 
3, the table top 32 is lowered to such an elevation that a closed 
supporting surface is established from the leading edge 18 of the carrier 
4 to the upright posts 6 and 8 and beyond these posts to a fixed work 
surface 73 which, for example, merges into a further fixed table top 74 as 
best seen in FIG. 5. At this point of the operation the partial stack 2 
which has been removed from the stack 3 may now be shifted by means of the 
holding and pushing mechanism 46 onto the support member 29 to any desired 
extent. The partial stack 2 may now be either directly transported to a 
work tool 75 such as a break-out mechanism for folding box blanks or the 
like. In the alternative, the partially removed stack 2 may be prepared in 
any other desired manner for further processing or for further 
transporting. 
The further operation of the present apparatus is as follows. First, the 
table top 32 is raised and the carrier 4 is returned into the initial 
position, whereby the rear edge 21 which has a slanted portion ridges 
upwardly on the also slanted forward edge 76' of the work surface 73 until 
the position shown in FIG. 1 is reached. Simultaneously, the holding and 
shifting device 46 is moved back to the righthand position shown in FIG. 1 
and then the stacking table 62 is raised until its stack has reached an 
elevation such that the desired number of stacked elements extends above 
the level of the carrier 4. Thereupon, the above described destacking 
operation is repeated. 
The penetration of the carrier 4 with its forward or leading edge 18 into 
the stack 3 is facilitated by lift moldings 76, one example of which is 
shown in FIG. 7. These lift moldings 76 are inserted into the stack 3 
prior to placing a stack on the stacking table 2, whereby a suitable 
number of such moldings may be used which are placed at the desired 
spacings corresponding to the height of the individually separated smaller 
stacks 2. 
The lift moldings 76 have about a width or length corresponding to that of 
the width of the supporting member 29. Each molding is provided with a 
slanted guide surface 77 which comes into contact with the carrier 4 or 
rather with the cover member 29 as the carrier 4 advances to the right. 
Thus, the slanted surface 77 guides the separation wedges 41 and 42 or it 
guides the belt cover member 29 which runs around the guide rollers 40 at 
the leading edge 18 of the carrier 4. With the aid of the lift moldings 76 
a trouble-free separation of the partial stack 2 from the stack 3 may be 
accomplished since the carrier 4 penetrates without difficulty into the 
stack 3 at the desired location. 
As shown in FIG. 7 the lift molding 76 comprises a strip of sheet metal 78 
which has been bent twice at right angles to provide a horizontal section 
79, a vertical section 81, and another horizontal section 80. The vertical 
section 81 and the horizontal section 79 form together with a metal gusset 
77', which may be welded to the bent strips 79, 81, the slanted surfaces 
77. The longer horizontal section 80 of the lift molding 76 is pushed into 
the stack 3 intermediate of two layers thereof until the vertical section 
81 contacts the stack 3. 
The foregoing specification describes certain examples. However, 
modifications may be made without departing from the present teachings. 
Thus, the cover member 21 may be modified by providing it preferably with 
a coating of "Teflon" (RTM) or the like. The cover member 29 may be made, 
for example, from a textile webbing coated with "Teflon" (RTM) and 
provided with burl type protrusions which facilitate the holding of a 
partial stack on the carrier 4. 
Although the invention has been described with reference to specific 
example embodiments, it will be understood, that it is intended to cover 
all modifications and equivalents within the scope of the appended claims.