EP0200922B1

EP0200922B1 - Cardboard feeder

Info

Publication number: EP0200922B1
Application number: EP19860104549
Authority: EP
Inventors: Takehiro C/O Mihara Machinery Works Of Takahashi
Original assignee: Mitsubishi Heavy Industries Ltd
Current assignee: Mitsubishi Heavy Industries Ltd
Priority date: 1985-04-05
Filing date: 1986-04-03
Publication date: 1989-07-12
Also published as: EP0200922A1; JPS61168036U; DE3664310D1; AU5558986A

Description

Background of the invention

1. Field of the invention

This invention relates to a machine for making cartons of cardboard such as corrugated sheet and, more particularly, to a cardboard feeder for use with the carton making machine which achieves smooth feeding of cardboards without causing defective feeding, collapse, and the like.

2. Description of the prior art

Fig. 4 is a schematic diagram of a conventional cardboard feeder 1. In this drawing, cardboards 5 are piled and stored in a hopper formed by a front stopper member 3 and a rear support member 4 provided on a table 2. A slide bar 6 embedded slidably in the table 2 is reciprocated by a crank mechanism 7. A kicker 8 is fixed on the slide bar 6 so that in response to the operation of the crank mechanism 7 the cardboards 5 in the hopper are kicked out in the direction of the arrow shown in the drawing through a slit formed at the lower end of the front stopper member 3 of the hopper each lowest one at a time. In front of the front stopper member 3 there are provided a pair of upper and lower feed rolls 9 and 10 so that the cardboard 5 sent out from the hopper is pinched between the upper and lower feed rolls 9 and 10 and in response to the rotation of the two rolls 9 and 10, is forwarded successively to a subsequent step. Fig. 5 is an enlarged front view of a portion A in Fig. 4. The upper feed roll 9 is divided into plural segments and supported rotatably, while the surface of the lower feed roll 10 is finished through knurling or made rough by forming it by rubber, for example. For clarity, a driving system of the upper and lower feed rolls 9 and 10 is not illustrated. Fig. 6 illustrated the state in which the cardboard 5 passes between the upper and lower feed rolls 9 and 10. As shown in Fig. 6, a gap g between the upper and lower feed rolls 9 and 10 is set by a gap adjusting unit provided separately, but not illustrated, so as to assume a spacing smaller than the thickness T of the cardboard 5. The reason is that if a feed force is absent or insufficient when the cardboard 5 is conveyed by the upper and lower feed rolls 9 and 10, the positions of printing and grooving being performed in the subsequent step at a certain timing are disordered, that is, the aim of setting the gap as above is to prevent occurrence of disorder of these positions and make uniform the product quality. In addition, the upper and lower feed rolls 9 and 10 must draw out surely the cardboard with a force sufficiently larger than the friction drag caused by being pinched between the total weight of cardboards 5 piled in the hopper and the upper surface of the table 2. In this connection, according to the conventional device, the gap g between the upper and lower feed rolls 9 and 10 had to be made considerably smaller than the thickness T of the cardboard 5 because the friction drag is of the static type and relatively large. As the result of the manner above of setting the gap, the degree of collapse of the cardboard 5 (see the shaded portions of Fig. 6) becomes large and the strength of a carton thus made is insufficient, thus, disqualified products tend to be manufactured many. To prevent such inconveniences, corrugated board of thick linerboard configuration had to be employed and this in turn caused another inconvenience, such as a waste of resources.
As described above, the conventional cardboard feeder had the problems that to draw out the lowest cardboard out of those stored in the hopper it is necessary to increase the pinching force of the upper and lower feed rolls, this tends to cause collapse of the cardboard just conveyed, and to prevent such collapse the raw cardboard must be thick.
A cardboard feeder as defined by the precharacterizing features of claim 1 is known from the US-A-3 994 489. This known cardboard feeder overcomes the deficiencies of the feeder discussed so far by having a feed bed comprising rolls contacting the under surface of the lowermost cardboard of the stack of cardboards. These rolls are mounted above a vacuum source in such a manner as to enable the lowermost cardboard to be flat while minimizing the friction between said cardboard and the feed bed. Said low friction is attained by mounting the rolls contacting the lowermost cardboard in a freely rotatable manner. Alternatively the rolls can be power driven. A specific mechanism for power driving the feed bed rolls in such a manner that friction is prevented between these rolls and the lowermost cardboard, however, is missing in this document.
For reducing friction between the lowermost cardboard in the cardboard feeder known from the FR-A-2 395 213 and the feed bed thereof, a plurality of continuous belts in contact with the undersurface of the lowermost cardboard are used. These belts are driven in conjunction with the kicker for kicking out the lowermost cardboard by the same drive mechanism. A free wheel mechanism is used to ensure the belts to be driven only in feed direction. Nevertheless considerable friction might arise between the lowermost cardboard being sucked to the belts by means of a vacuum source, because no provisions are arranged to synchronize the movement of the kicker and the belts.

Summary of the invention

It is the object of the present invention to provide a cardboard feeder of the kind defined by the precharacterizing features of claim 1, which ensures the absence of friction between the lowermost cardboard and the feed bed of the feeder.
This object is attained by the characterizing features of claim 1.
The synchronization of the kicker operation with the feed bed rolls by means of a ratchet containing gear mechanism in such a manner that the speed of the top kicker is set so as to coincide substantially with the peripheral speed of the feed bed rolls ensures that no friction is caused within the feed bed of the cardboard feeder.

Brief description of the drawings

Fig. 1 is a schematic side view of a cardboard feeder according to an embodiment of the present invention;
Fig. 2 is a sectional view taken in the direction of the arrows B-B of Fig. 1;
Fig. 3 is a partial front view of a roll in another embodiment of the present invention;
Fig. 4 is a schematic side view of the conventional cardboard feeder;
Fig. 5 is an enlarged front view of a portion A of Fig. 4; and
Fig. 6 is a side view showing the state in which a cardboard is pinched between upper and lower feed rolls and sent out thereby.

Description of the preferred embodiments

Embodiments of the present invention will now be described with reference to the drawings, in which Fig. 1 is a schematic side view of a cardboard feeder according to an embodiment of the present invention and Fig. 2 is a sectional view taken in the direction of the arrows B-B of Fig. 1.
In Figs. 1 and 2, a cardboard feeder indicated by reference numeral 1 functions as a device for kicking out forward the lowest one of cardboards 5 piled in a hopper formed by a front stopper member 3 and a rear support member 4 provided on a table 2 by the use of the reciprocating motion of a kicker 8 projecting from the upper surface of the table 2. The cardboard thus kicked is pinched between a pair of upper and lower feed rolls 9 and 10 disposed in a station subsequent to the cardboard feeder 1, so that it is forcedly taken and sent out. The kicker 8 is fixed on a slide bar 6 slidable inside the table 2 so that it can reciprocate together with this slide bar 6. The slide bar 6 in turn is reciprocated by means of a crank mechanism 7 disposed therebelow. The foregoing configuration of the device is similar to the conventional cardboard feeder shown in Fig. 4. Besides the foregoing configuration, rolls 11 are included which form an important portion of the present invention. As shown in Fig. 2, gears 12 are secured on either end of each roll 11. The roll 11 is arranged so that its upper point is substantially flush with the surface of the table 2. Inside the gear 12 a ratchet mechanism is accommodated for rotating the shaft of the roll in one direction, that is, in the embodiment illustrated these are designed so that the roll 11 can rotate only in the feed direction of cardboards. Reference numeral 13 indicates a gear whose upper point is in gear with the gear 12 accommodating the ratchet mechanism with its lower point being in gear with a rack 14 provided underside the slide bar 6. Although the embodiment illustrated in Figs. 1 and 2 includes six gears 12 each accommodating the ratchet mechanism therein provided on either side of the cardboard feed station, i.e. six rolls 11 arranged in parallel with one another, the number of rolls may be one or more and as shown in Fig. 3, a roll composed of a plurality of short rolls 11 a supported by one shaft may be employed in place of one long roll 11.
Originally, it is desirable that the cardboards 5 piled in the hopper be kicked out by the kicker 8 and sent smoothly into the subsequent step by the upper and lower feed rolls 9 and 10 at an accurate timing without causing any collapse of the cardboard each lowest one at a time. According to the embodiment of the foregoing configuration, the rolls 11 are provided in the table 2 with their upper points being substantially flush with the upper surface of the table 2, the rolls 11 are driven only when the kicker 8 moves forward (only at the time of kicking out the cardboard 5), and the top speed of the kicker 8 is set so as to coincide substantially with the peripheral speed of the rolls 11; thus, the friction drag caused by . the face of the table 2 is reduced and the cardboard 5 kicked out by the kicker 8 can be sent forward by a small force even while it is conveyed by the upper and lower feed rolls 9 and 10, consequently, the cardboard 5 is collapsed little and a processing in the subsequent step can be performed accurately, thereby resulting in the advantages of enhancing the product quality and of saving resources.
As described hereinabove, according to the present invention, the cardboards are sent out smoothly from inside the hopper; thus, a waste of resources and a fall of strength of products that would otherwise result from collapse of the cardboard can be prevented from arising, and the degree of accuracy of printing, grooving, and like processes done in the subsequent step can be improved.

Claims

1. A cardboard feeder comprising upper and lower feed rolls (9 and 10) for gripping and sending cardboards towards a subsequent step, a kicker (8) operated by a drive mechanism (7) for kicking out the lowermost cardboard (5) of a stack of said cardboards towards said upper and lower feed rolls (9 and 10), and rolls (11) disposed so as to contact with the under surface of said lowermost cardboard (5), characterized in that said rolls (11) are operated by said drive mechanism (7) via a gear arrangement (12-14), and in that a ratchet mechanism is provided inside that gear (12) of said gear arrangement (12-14) which is secured to each of said rolls (11) respectively for rotating the rolls (11) only when the kicker (8) is moved forward by the drive mechanism (7) for kicking out the lowermost cardboard (5), the top speed of the kicker (8) being set so as to coincide substantially with the peripheral speed of the rolls (11).

2. The cardboard feeder according to claim 1, wherein said drive mechanism (7) is a crank mechanism.

3. The cardboard feeder according to claim 1, wherein each of said rolls (11) contacting the under surface of the lowermost cardboard (5) is composed of a plurality of short rolls supported by one shaft.