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(11) | EP 0 082 475 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Device for feeding semirigid strip from a loader |
| (57) The device comprises at least one suction cup element (32) effective to be located
below the middle portion of the lowermost strip (19) of a strip stack (18) and effective
to flex it by suction away from the overlying strips and along the path of movement
of a pusher (22), the strip stack (18) introduced in the loader being held by base
supports located substantially at the ends of the lowermost strip (19). Thus the strips
can be reliably ejected, one strip at a time, toward subsequent processing steps. |
[0001] This invention relates to a device for feeding semirigid strips from a loader, in particular wooden strips for the fabrication of packing boxes.
[0002] As is known, the fabrication of packing boxes involves the orderly feeding of strips intended to form, as an example, the bottoms of the boxes. However, this orderly feed is not simply achieved because, to minimise costs and materail wastage, the wooden strips employed in such fabrication processes are made extremely thin, and as such, mainly pose two orders of problems.
[0003] A first order of problems is how to achieve an accurate high speed delivery onto the conveyor belts which transport said strips to subsequent processing stations. These problems have been solved by the strip feeding device which forms the subject of published Italian Patent Application No. 26,824 A/80, by this same Applicant.
[0004] The second order of problems is how to provide for said device, or any other similar device, to handle the semirigid strips by always delivering one of them at a time to subsequent processing, notwithstanding their thin dimensions.
[0005] It frequently happens, in fact, that two or more strips are ejected simultaneously which are superimposed in close mutual contact together. It will be apparent how this results in wasted material, and above all in the danger of binding both the strip feeding device and the machines that are to carry out subsequent working processes. Also apparent will be how each such malfunctions can quite appreciably increase the cost of the industrial process, by slowing it and making the intervention of skilled personnel unavoidable.
[0006] Accordingly, the task of this invention is to provide a device for feeding semirigid strips from a loader, which can reliably eject one strip at a time toward subsequent processing steps.
[0007] Within the above mentioned task, it is a particular object of the invention to provide a device as indicated, which is compatible with the device disclosed in the cited patent application by the same Applicant, to thus form a fully satisfactory apparatus from any standpoints.
[0008] Yet another object of this invention is also to provide a device as indicated, for feeding semirigid strips, which can afford, also in the particular embodiment thereof which will be described and illustrated hereinafter, non-obvious features and teachings for the expert in the art, such as to represent a step forward with respect to the state cfthe art.
[0009] According to one aspect of the invention the above task md objects, as well as yet other objects, such as will be apparent hereinafter, are achieved by a device for feeding semirigid strips from a loader, of the type provided with pusher means adapted to move the lowermost strip in said loader toward a conveyor belt, characterised in that it comprises at least one suction cup element located below the middle portion of said lowermost strip and effective to flex by suction said strip away from the overlying strips and along the path of movement of said pusher means, and in that a stack of strips introduced in said loader is held by base supports located substantially at the ends of said lowermost strip.
[0010] Further features and advantages will be more apparent from the following description of a preferred but not limitative embodiment of the invention, as shown by way of illustration and not of limitation in the accompanying drawings, where:
Figure 1 shows, partly in full view and partly in section, taken through the pusher means, a portion of the inventive device located at the loader area;
Figure 2 shows, to an enlarged scale with respect to Figure 1, the active element of the pusher means which directly engages with the strips;
Figure 3 illustrates the control unit for the inventive device;
Figure 4 is a partial schematic sectional view of the device of Figure 1, taken along a centreline;
Figure 5 is similar to Figure 4 and illustrates further elements of this device;
Figure 6 is a schematical front view of the device construction at the bottom of a strip stack;
Figure 4a is a view similar to Figure 4, showing a modified embodiment of the suction device for a strip to be withdrawn, wherein the suction cup proper is replaced with a suction box;
Figure 5a illustrates, as viewed in the direction of the arrow A of Figure 4a, the suction box fitted with a grid-like top surface; and
Figure 6a is a similar view to Figure 6, taken in the direction of the arrow B of Figure 4a.
[0011] Making reference to the cited drawing figures, the device of this invention comprises a terminating group 1 supporting a loader 2 which contains a stack 3 of strips and is located above a conveyor belt 4, as well as a control unit 5 connected to a main drive shaft 6 of the conveyor belt 4.
[0012] The control unit 5 comprises essentially a main cam 7 rigid with the main shaft 6, a cam follower 8 keyed to an auxiliary shaft 9, and a fluid dynamic cylinder 10 operative against the bias of the cam follower 8 through a first bar 11.
[0013] Also keyed to the auxiliary shaft 9 is a deflector bar 12 which, through the intermediary of a link 13 will transmit the movement of the cam follower 8 to the terminating group 1, and specifically to a shaft 14, through a second bar 15.
[0014] Attached to the shaft 14 is a second deflector bar 16 which controls, through a swivel element 17, pusher means acting on the strips 18 of the stack 3.
[0015] It is advantageously provided, moreover, for the conveyor belt 4 to move closer to each ejected lowermost strip 19, by moving oppositely to said pusher means small brackets 20 defining seats 21 therebetween for the ejected strips.
[0016] Also provided are auxiliary members 2a which form in practice pressure members adapted to impart, to each lowermost strip 19 during the ejection thereof, a compressive motion toward its respective seat 21.
[0017] In a more specific way, the terminating group 1 may be constructed as disclosed in the above identified applicant's Patent Application No. 26,824 A/80, which is incorporated hereto for reference purposes.
[0018] Advantageously, provision is made for said pusher means, generally designated with the reference numeral 22, to include at least one pair of parallel co-planar foil-like elements 23 which are movable in grooves 23a (Figure 6) arranged symmetrically with respect to the middle of the strips 18, as well as respective active elements 24 engaging with a bracket 25 rigid with the foil-like elements 23.
[0019] Figure 2 illustrates the construction of an active element 24, and its engagement with a respective bracket 25. It will be appreciated that the active element presents a rounded lead-in shape to a dog 26 for pushing on a lowermost strip 19. Moreover, the active element 24 is engaged swivel-fashion through a pivot pin 27 with the bracket 25, and a pin-like spring 28, wound around the pin 27, is provided which acts to hold the pusher dog 26 raised, so that relatively raised strips can also be engaged.
[0020] Figure 6 shows how the loader 2 includes, in vertical alignment with the grooves 23a which define the lines of action of the active elements 24, stop or detent elements 29 having at the bottom a lug 30 which leaves a space free between itself and the respective groove, proportioned with the lowermost strip 19 being ejected.
[0021] Figure 6 also shows that the positions of the grooves 23a and of the base supports 31 for the loader 2 are such as to only allow one such flexed strip therethrough, away from the overlying strips 18 in the stack 3.
[0022] It is in fact contemplated that, centrally to said strips, between the grooves 23a, a suction cup element 32 be provided which is effective to flex by suction the lowermost strip 19 being moved away from the overlying strips 18 and along the path followed by the pusher means 22. Furthermore, and advantageously, the suction cup element 32 is associated with first control means 33 (Figure 4) operative to impart to it first oscillation capabilities in the direction of the lowermost strip 19, and with an oscillating support or holder 34,adapted to impart to the suction cup element 32 second oscillation capabilities in a parallel direction to the ejection movement of the lowermost strip 19. Lastly, the suction cup element 32 is activated intermittently through the action of second control means 35, shown in Figure 5.
[0023] More in detail, the first control.means 33, shown best in Figure 4, are of a mechanical type and derive their motion from the shaft 14 which drives the pusher means 22. In practice, keyed to the shaft 14 is an auxiliary cam 36 engaging a cam follower 37 which transmits its oscillations to a pushrod 38 of adjustable length. The pushrod is pivoted to a first lever 39 and acts thereon against the bias of a tension spring 40.
[0024] The first lever 39 oscillates about a pin 41, and on the side away from said pin acts on a second lever 42 with the intermediary of elastic means.
[0025] The second lever 42 oscillates about a second pin 43 substantially aligned with the former pin.41 of the first lever 39, and the elastic means are such as to provide for spreading the first and second levers apart when the second lever is prevented from rotating. In detail, said elastic means includes a compression spring 44 extending from one end of the first lever 39 to a detent cup 45. The latter is engaged with a nut 46 rigid with a shank 47 extending through the compression spring 44 and ending in an expanded head 48 behind the second lever 42. In practice, the first lever 39 will push on the compression spring 44, and the latter act on the second lever 42 through its head 48.
[0026] The second lever 42 ends below the stack 3 of strips 18 in a shaped lug 49 at least at its end configured yoke-like.
[0027] With the shaped lug 49, there is engaged said oscillating support 34 which holds the suction cup 32 directly. The oscillating support or holder 34 is pivoted at the bottom to the shaped lug 49 by means of a pin 50, and has substantially a U-like cross-sectional configuration partly enclosing the bottom of the suction cup 32. Figures 4,5 and 6 show how the oscillating support 34 engages with the suction cup element 32 by means of a throughgoing pin 51 which is also connected to elastic bias means 52, e.g. tension springs stretched between said throughgoing pin 51 and a small pin 53 through the second lever 42.
[0028] Figure 5 illustrates the second control means 35 operative to control the action of the suction cup element 32 in synchronization with the movements of the suction cup element itself. Said second control means comprises a link 54 extending between the oscillating support 34 and a control unit 55 for controlling the suction force applied to the suction cup element 32. The link 54 extends through the oscillating support 34 and is arranged in abutment relationship therewith through a widening 56, it being pivoted at the opposed end to a small piston 57: protruding out of the control unit 55.
[0029] The piston 57 extends into the control unit 55 far enough to penetrate a conduit 58 connected to the air suction pump. In particular, the piston 57 enters the area of confluence of the conduit 58 and hose 59, the hose 59 being connected to the suction cup element 32 and to vents 60 arranged at the end of the conduit 54.
[0030] In detail, the piston 7 is shaped with a conically expanding portion 61 adapted to cover the vents 60 under the action of a small compression spring 62, and with disks 63 at the hose 59 connection to the conduit 58. Said disks 63 have a cutout front shape for admitting air therethrough.
[0031] The inventive device, described hereinabove primarily with reference to its construction, operates as follows.
[0032] As shown in Figure 1, the pusher means 22 acts on each lowermost strip 19 through the pusher dog 26 formed on the active element 24 which can oscillate about the pin 27. The active element 24 is rounded off and at the same time biased by the pin spring 28 to a raised position such as to reliably grasp even relatively raised lowermost strips 19.
[0033] During the ejection step, the lowermost strips 19 are thrown into the seats 21 on the conveyor belt 4 moving toward them. The insertion of the strips is facilitated by the auxiliary members 2a compressing them downwards.
[0034] While the positive engagement of at least one strip is assured by the shape of the active element 24, the ejection of a single lowermost strip 19 at each stroke of the active elements 24 is assured by the suction cup element 32 and the movements imparted thereto.
[0035] In fact, the same shaft 14 which drives all the active elements 24 (through the second deflector bar 16, swivel element 17, and foil-like element 23) also produces the action of the first control means 33 which alternately move the suction cup element 32 to.and away with respect to the strip stack 3.
[0036] Specifically, and as shown in Figure 4, the first control means 33 define a kinematic train which extends from the auxiliary cam 36 to the first lever 39 and hence to the second -ever 42. The first lever 39 is oscillated to raise and lower under control by the auxiliary cam 36 and entrains therealong, through the intervening elastic means, the second lever 42. In practice, when no resisting force is applied to the suction cup element 32, the second lever 42 oscillates as if it was rigid with the first lever 39 and,when an obstacle prevents the suction cup element 32 from raising, the second lever 42 is stopped and the first lever 39 continues its travel to compress the compression spring 44. Thus, the suction cup element 32 can be moved forward toward the lowermost strip 19 and be pressed powerfully thereon without creating binding conditions in the cited kinematic train.
[0037] At each revolution of the shaft 14, and hence each cycle of the pusher means 22, the suction cup element 32 is brought close to and pressed on the lowermost strip 19 in the stack 3, whereafter the suction cup element 32 is again lowered to separate the lowermost strip 19 from the remaining strips 18, as shown best in Figure 6.
[0038] Figure 6 also shows how the ejection of the lowermost strip 19 becomes possible only after the latter assumes said lowered position, by inserting itself into the space left below the lugs 30 provided on the stop elements 29.
[0039] The suction cup element 32 advantageously follows the strip 19 being ejected, at least through a certain distance. In fact, the suction cup element is held on the second lever 42 by the oscillating support 34 which, opposing the elastic return means 32, can rotate about the pin 50 and follow the movement of the lowermost strip 19 as imparted by the pusher means 22. Of course, this forward movement cannot be extended too much in time, thereby the second control means 35 are brought into operation, which remove the suction force from the suction cup element.
[0040] In practice, as shown in Figure 5, the oscillating support 34, in moving forward together with a strip being ejected, entrains therealong the link 54 and piston 57 against the bias of the spring 62. The movement of the piston 57 uncovers the vents 60 provided in the control unit 55, with consequent practical nullification of the suction force through the flexible hose 59 which, in normal conditions, is the only connection between the suction cup element 32 and conduit 54, which is connected to a suction pump.
[0041] It follows that,whereas the synchronisation of the first control means 33 with the pusher means 22 is derived from the shaft 14, which is common to both, the synchronisation of the second control means 35 is derived directly from the ejection movement of the lowermost strip 19.
[0042] With reference to the embodiment of the invention shown in Figures 4a,5a,6a, it is to be noted that the assembly which draws the lowermost strip in the stack from below comprises a preferably stationary box 70, which has at the top a suction grid 71 (shown in Figure 5a) in the form of a plate of sheet metal having slots 72.
[0043] Said box 70 is located at a small distance (e.g. a few millimeters away) from the pack of strips 18.
[0044] The box 70 is connected, by means of a pipe 73, to a continuous suction source, not shown, and the suction capability of the assembly is such that the lowermost strip 19 in the stack is drawn toward the grid, thus allowing the strip to be engaged by the element 24.
[0045] The device of this invention achieves its objects and secures many important advantages. First of all, that of assuring not only an accurate and fast delivery of said strips, but also the virtual certainty that,at each delivery,one strip only is delivered to the respective seat 21 on the conveyor belt 4.
[0046] Furthermore, through comparatively simple instruments, accurate and complex movements have been made possible for the suction cup element which separates the lowermost strip from the overlying stack of strips.
[0047] It is finally important to observe that the device is also advantageous in its specific technical aspects as deducible from the specification and drawings, and evident for a person skilled in the art, over similar conventional arrangements. As an example, the device is highly compact and adaptable to widely different situations and many apparatus for feeding semirigid strips of any desired types.
1. A device for feeding semirigid strips from a loader, of the type provided with
pusher means adapted to move the lowermost strip in said loader toward a conveyor
belt, characterised in that it comprises at least one suction cup element (32) located
below the middle portion of said lowermost strip (19) and effective to flex by suction
said strip (19) away from the overlying strips and along the path of movement of said
pusher means (22), and in that a stack of strips (18) introduced in said loader is
held by base supports located substantially at the ends of said lowermost strip (19).
2. A device according to Claim 1, characterised in that said suction cup element (32)
is movable perpendicularly to the plane of lay of said lowermost strip (19) under
the action of first control means (33) synchronised with said pusher means (22).
3. A device according to Claim 2, characterised in that said first control means (33)
are of the mechanical type and comprise a kinematic train taking the start from an
auxiliary cam (36) keyed to a shaft (14), said shaft (14) also controlling said pusher
means (22).
4. A device according to Claim 3, characterised in that elastic means are included
in said kinematic train which are adapted to permit the position of said suction cup
element (32) to be out of phase with respect to the members of said kinematic train.
5. A device according to Claim 4, characterised in that said kinematic train comprises:
a cam follower (37) engaging with said auxiliary cam (36), a pushroad (38) controlled
by said cam follower (37), a first lever (39) movable against the bias of a tension
spring (40) under impulsion by said pushrod (38), a second lever (42) actuated by
said first lever (39), and elastic means intervening between said first (39) and second
levers (42).
6. A device according to Claim 2, characterised in that said suction cup element (32)
is supported by said first control means (33) such as to be oscillable parallel to
the direction of movement of said lowermost strip (19) during the ejection step.
7. A device according to Claims 5 and 6, characterised in that said suction cup element
(32) is carried on an oscillating support (34) adapted for oscillation against the
bias of elastic return means located at one end of said second lever (42).
8. A device according to Claim 6, characterised in that said suction cup element (32)
is activated and deactivated in synchronisation with the movement of said lowermost
strip (19) being ejected through a second control means (35) operative to control
the suction force of said suction cup element. (32).
9. A device according to Claim 8, characterised in that said activation and deactivation
of said suction cup element (32) are controlled by the movement of a strip (19) being
ejected.
10. A device according to Claims 7,8,9, characterised in that said second control
means (35) comprises a link (54) engaged at one end with said oscillating support
(34) and connected at the other end to a small piston (57) included in a control unit
(55) whereto a conduit (58) from a suction pump is connected, said control unit (55)
including fittings for a flexible hose (59) connecting said conduit (58) to said suction
cup element (32), and vents (60) connecting said conduit (58) to the environment outside
said control unit (55), the movement of said piston (57) connecting said conduit (58)
alternately to said hose (59) and said vents (60).
11. A device according to Claim 1, characterised in that said pusher means (38) comprises
an end-mounted active element (24), said active element (24) being rounded off and
provided at the top with a pusher dog (26) and held substantially raised by a pin
spring (28).
12. A device for feeding semirigid strips from a loader, according to Claim 1 and
characterised in that said suction element (32) comprises a box located shortly away
from the lowermost strip (19) in the loader and provided with passageways facing said
strip (19) and being connected to a suction source.
13. A device according to Claim 12, characterised in that said passageways are in
the form of slots, holes, and the like.
14. A device for feeding semirigid strips from a loader, according to the preceding
claims and as herein described and illustrated for the objects specified.