Sheet feeding apparatus for a corrugated fiberboard container making machine

Abstract: The apparatus has front stops (27) disposed at two locations spaced in the width direction to true up the front edges of stacked corrugated fiberboard sheets (7) and is constructed so as to feed a lowermost corrugated fiberboard sheet (7) successively from the front end side of the front stop (27). The front stops (27) at the two locations are constructed so as to be movable in the longitudinal direction in such a manner as to be capable of supporting the corrugated fiberboard sheets (7) while tilting the front edges thereof obliquely in the longitudinal direction.

Description: BACKGROUND OF THE INENTION AND RELATED ART STATEMENT 1. Field of the Invention The present invention relates to a sheet feeding apparatus for a corrugated fiberboard container making machine for feeding stacked corrugated fiberboard sheets one after another. 2. Description of Related Art FIGS. 8 and 9 are explanatory views showing outlines of conventional sheet feeding apparatuses for a corrugated fiberboard container. In FIG. 8, frames 1 are erected on both sides, right and left, of a table 2, and a beam 3 is installed between the frames 1. A hopper 6 is defined by front stops 4 attached to the beam 3 and side guides 5, and corrugated fiberboard sheets 7 are stacked on the table 2 in this hopper 6. A lowermost sheet 7a of the stacked corrugated fiberboard sheets 7 is kicked from one end side by a kicker 8 and reaches feed rolls 9 on the other end side as indicated by the chain line. Then, the sheet 7a is pulled by the feed rolls 9 and is sent to the following process (for example, a printing section 10). FIG. 9 shows an outline of a sheet feeding apparatus of another type. In this sheet feeding apparatus, delivery rolls 11 are provided under the front stops 4 in place of the kicker 8, and the vacuum pressure in a vacuum box (suction box) 12 attracts the lowermost sheet 7a to the surface of the delivery rolls 11, so that the sheet 7a is delivered by a frictional force. The above-described conventional sheet feeding apparatuses for a corrugated fiberboard box making machine have problems as described below. For example, if the feed roll 9 wears eccentrically, the feeding force becomes nonuniform in the transverse direction. Also, in the case shown in FIG. 9, if the corrugated fiberboard sheet 7 is warped, the contact pressure between the delivery roll 11 and the lowermost sheet 7a of the corrugated fiberboard sheets 7 becomes nonuniform in the transverse direction even with the aid of the suction pressure of the vacuum box 12. Particularly for a corrugated fiberboard sheet with high flexural rigidity such as a double-sided sheet, such tendency is remarkable. Thus, when a feeding force that is nonuniform in the transverse direction is applied to the corrugated fiberboard sheet 7 under the mechanical condition of eccentric wear of the feed roll 9 or under the condition of warped sheet 7, the sheet 7 is fed while being turned obliquely at a predetermined angle as shown in FIG. 10. The sheet 7 fed in this manner decreases the accuracy of box made in the subsequent process. Therefore, the accuracy is kept by a correction, for example, by decreasing the sheet feed speed or by purposely installing the kicker 8 slantwise. Since such a tendency for oblique turning is often developed by the eccentric wear of the feed roll 9, the warping of the corrugated fiberboard sheet 7, and the like as described above, the oblique turning does not occur at random for each corrugated fibreboard sheet 7, but there is a tendency for all corrugated fibreboard sheets 7 of a certain production lot to be turned obliquely in the same manner. The present invention has been developed in view of the above situation, and accordingly an object thereof is to provide a sheet feeding apparatus for a corrugated fibreboard box making machine in which even if corrugated fibreboard sheets have a tendency for oblique turning, the tendency for oblique turning can be adjusted easily. The present invention provides a sheet feeding apparatus for a corrugated fibreboard box making machine, which has front stops disposed at two locations spaced in the width direction to true the front edges of stacked corrugated fibreboard sheets and is constructed so as to feed a lowermost corrugated fibreboard sheet successively from the front end side of said front stop, wherein said front stops at the two locations are constructed so as to be movable in the longitudinal direction in such a manner as to be capable of supporting the corrugated fibreboard sheets while tilting the front edges thereof obliquely in the longitudinal direction, characterised in that the front stops are disposed at two locations on a beam which extends in the width direction and which can be tilted slantwise in the longitudinal direction with one end thereof in the width direction being a fulcrum. While German Patentschrift No 275050 discloses a sheet feeding apparatus which might be considered to fall within the preamble of the foregoing statement, it lacks the tiltable beam. Since the two front stops are disposed on a beam which can be tilted slantwise in the longitudinal direction, the positions and directions of the two front stops can be changed at the same time merely by changing the tilt of the beam. Therefore, even if corrugated fibreboard sheets have a tendency for oblique turning, the tendency for oblique turning can be easily and quickly adjusted, for example to a straight state. Further features and advantages of the invention will become clear on a reading of the following more detailed description of an embodiment of the invention made with reference to Figures 1 to 4 of the accompanying drawings. Figures 5 to 7 show another sheet feeding apparatus which does not fall within the present claim, but which are considered helpful in leading to a fuller understanding of the present invention. In the drawings: Figure 1 is a front view of a sheet feeding apparatus for a corrugated fibreboard container making machine in accordance with an embodiment of the invention; Figure 2 is a sectional view taken along the line A-A of Figure 1; Figure 3 is a sectional view taken along the line B-B of Figure 1; Figure 4 is a plan view showing the operation of the sheet feeding apparatus of Figures 1 to 3; Figure 5 is a sectional view of a principal portion of a sheet feeding apparatus for a corrugated fibreboard container making machine not according to the present invention; Figure 6 is a sectional view taken along the line C-C of Figure 5; Figure 7 is a sectional view taken along the line X-X of Figure 5; Figure 8 is an explanatory view of a conventional sheet feeding apparatus for a corrugated fibreboard container making machine; Figure 9 is an explanatory view of another conventional sheet feeding apparatus for a corrugated fibreboard container making machine; and Figure 10 is a plan view showing a problem with the conventional sheet feeding apparatus. In the embodiment of Figures 1 to 4, the sheet feeding apparatus has front stops 27, which are disposed at two locations a predetermined distance away from each other in the transverse (width) direction, for truing up the front edges of the sheets 7 so that a lowermost corrugated fibreboard sheet 7 is fed successively from the front end side. The front stops 27 at the aforesaid two locations are constructed movably in the longitudinal direction so as to be capable of supporting the corrugated fiberboard sheets 7 while tilting them obliquely in the longitudinal direction. The front stops 27 are mounted at two predetermined locations of a beam 22 which extends in the transverse direction and is capable of being tilted obliquely in the longitudinal direction with one end in the transverse direction being a fulcrum, and are constructed so as to support the corrugated fiberboard sheets 7 while tilting the front edges thereof obliquely in the longitudinal direction by moving together with the beam 22. Next, the above-described construction will be described in more detail. Of the frames 1 disposed at right and left, the frame 1 located on the right side in FIGS. 1 and 2 is fitted with a mounting base 21 by welding or other means. On this mounting base 21, one end of the beam 22 is supported via a fulcrum pin 23 so as to be rotatable in the longitudinal direction with respect to the sheet advance direction. The other end of the beam 22 is slidably supported via a groove portion formed so as to hold a support base 24 fixed to the frame 1 on the opposite side (left side). As shown in FIG. 3, the beam 22 is fitted with a bracket 25 having a U shape in cross section and a keep plate 26 which are slidable in the axial direction (transverse direction). The bracket 25 and the keep plate 26 enclose the beam 22. A face of the bracket 25 on the side opposite to the beam 22 is formed with a dovetail groove 25a, and the front stop 27 is fitted in this dovetail groove 25a so as to be slidable in the vertical direction. On a mounting base 28 fixed to the upper part of the front stop 27 is mounted a motor 29. A screw shaft 30, which is fixed to the shaft of the motor 29, engages with a screw hole 25b in the bracket 25. Therefore, when the motor 29 is rotated, the screw shaft 30 goes into and out of the bracket 25, and accordingly the front stop 27 moves vertically, so that a gap between the lower edge of the front stop 27 and the table 2 can be changed according to the thickness of the corrugated fiber board 7 being worked. A motor 31 is mounted above the support base 24 of the frame 1 on the sliding side of the beam 22, that is, on the left side. On the shaft of this motor 31 is fixed an eccentric ring (eccentric cam) 32, which fits in an oval-shaped groove 22a in the beam 22. Therefore, when the motor 31 is rotated, the beam 22 sways in the longitudinal direction (sheet advance direction) with the fulcrum pin 23 being a fulcrum. In the sheet feeding apparatus for a corrugated fiberboard box making machine constructed as described above, by rotating the motor 31, the beam 22 is tilted obliquely in the longitudinal direction with the fulcrum pin 23 being a fulcrum, so that the two front stops 27 provided on the beam 22 also move in the longitudinal direction in a tilted manner. That is to say, a hopper 6 can be tilted as shown in FIG. 4. Therefore, if the corrugated fiberboard sheet 7 is turned obliquely, for example, at an angle of α when the sheet 7 is fed from the normal position of the hopper 6, at which position the sheet 7 is not tilted (the front edges of the corrugated fiberboard sheets 7 are arranged perpendicularly to the sheet advance direction), the two front stops 27 are tilted at the turning angle a of the corrugated fiberboard sheet 7 in the reverse direction in advance, whereby the posture of the corrugated fiberboard sheet 7 can be corrected. Therefore, the corrugated fiberboard sheet 7 takes a correct posture when being fed and reaching the downstream process such as a printing section, that is, the corrugated fiberboard sheet 7 can be fed straight from the table 2 to the next process. Thereupon, unlike the conventional sheet feeding apparatus, there is no need for decreasing the sheet feed speed or for correcting the attachment of a kicker, and the feed direction of the corrugated fiberboard sheet 7 can be adjusted easily. Further, merely by changing the tilt of the beam 22, the positions and directions of the two front. stops 27 can be changed at the same time, so that the direction of the corrugated fiberboard sheet 7 can be corrected quickly. Figures 5 to 7 show a different form of sheet feeding apparatus not in accordance with the present invention, the same reference numerals being used for elements which are similar to those in Figures 1 to 4. In the embodiment of Figures 1 to 4, the beam 22 is tiltable. However, in Figures 5 to 7 the beam 3 is fixed to the frames 1 as before, and the two front stops 27 themselves can be made movable in the longitudinal direction with respect to the beam 3, by which the direction in which the corrugated fiberboard sheets 7 are held by the two front stops 27 can be changed easily. Specifically, the beam 3 fixed to the frames 1 is fitted with an inside bracket 40 by using a keep plate 41, and the inside bracket 40 is configured so as to be slidable on the beam 3 in the axial direction (lengthwise direction). Also, on the outside of the inside bracket 40, an outside bracket 42 is installed by being guided by a key member 44 so as to be slidable to the right and left in FIG. 5 (longitudinally with respect to the sheet advance direction). A keep plate 43 is installed on the opening side of the outside bracket 42 to prevent the outside bracket 42 from coming off from the inside bracket 40. A face of the outside bracket 42 on the side opposite to the beam 3 is formed with a dovetail groove 42a, and the front stop 27 is fitted in this dovetail groove 42a so as to be slidable in the vertical direction and can be moved vertically by the motor 29 as in the case of the embodiment of figures 1 to 4 . A motor 45 is mounted above the outside bracket 42, and the shaft thereof passes through the outside bracket 42 and projects toward an oval-shaped groove 40a in the inside bracket 40. On the shaft of the motor 45 is fixed an eccentric ring (eccentric cam) 46, which fits in the oval-shaped groove 40a. Therefore, when the motor 45 is rotated, the outside bracket 42 is moved in the direction indicated by an arrow 47 in FIG. 5 (longitudinally with respect to the sheet advance direction) with respect to the inside bracket 40, and therefore with respect to the beam 3 according to the rotational angle of the eccentric ring 46. That is to say, the two front stops 27 are independently moved longitudinally with respect to the sheet advance direction, whereby the direction of the front edge of the corrugated fiberboard sheet 7 can be changed easily. Of two sets of the front stops, one set may be fixed to the beam 3 as before and one set may be adjustable longitudinally. Alternatively, both of the two sets may be adjustable. The sheet feeding apparatus for a corrugated fiberboard box making machine constructed as described above is suitable for fine adjustment of direction of the corrugated fiberboard sheet 7 because the front stops 27 can independently be moved in the longitudinal direction. In addition, this sheet feeding apparatus achieves the same operation and effect as in the case of the embodiment of figures 1 to 4, except that although the side guides 5 fixed to the beam 22 are tilted in the same way as the front stops 27 in the first embodiment, the side guides 5 are fixed in the different form of sheet feeding apparatus. However, since the quantity of tilt is very small (several millimeters at the position of the eccentric ring 32 in the embodiment of figures 1 to 4), whether the side guides 5 tilt or not has no effect on the performance of the sheet feeding mechanism.

Claims: A sheet feeding apparatus for a corrugated fibreboard box making machine, which has front stops (27) disposed at two locations spaced in the width direction to true the front edges of stacked corrugated fibreboard sheets (7) and is constructed so as to feed a lowermost corrugated fibreboard sheet successively from the front end side of said front stop, wherein said front stops at the two locations are constructed so as to be movable in the longitudinal direction in such a manner as to be capable of supporting the corrugated fibreboard sheets while tilting the front edges thereof obliquely in the longitudinal direction, characterised in that said front stops are disposed at two locations on a beam (22) which extends in the width direction and which can be tilted slantwise in the longitudinal direction with one end (22) thereof in the width direction being a fulcrum (23).

Inventors: BABA YASUYUKI, HATANO OSAMU, BABA, YASUYUKI, HATANO, OSAMU, Baba, Yasuyuki, Mihara Machinery Works, Hatano, Osamu, Mihara Machinery Works
Applicants: MITSUBISHI HEAVY IND LTD, MITSUBISHI HEAVY INDUSTRIES, LTD.
Application year: 1999
Main classification: B65H9
IPC codes: B65H1, B65H9