Single facer

Abstract: The single facer of the present invention comprises an apparatus for automatically adjusting a gap between rolls (1, 2, 3), i.e., an apparatus for maintaining a roll gap at constant. The apparatus for adjusting the distance between the centers of the roll shafts is operable to move one roll toward the other by actuating driving means. The driving means is controlled in response to the variation in the temperature of the frame which supports the driving means or the roll in place, or to the passage of time after a heating means for heating the roll has started operation.

Description: FIELD OF THE INVENTION AND RELATED ART STATEMENT The present invention relates to a single facer comprising an apparatus for correcting a distance between the centers of shafts which is adapted to adjust (correct) a contacting condition between a lower roll and other rolls such as a top roll, a press roll and a gluing roll etc., which are in contact with said lower roll. Fig. 1 conceptionally illustrates a typical single facer which has been used in a traditional corrugating machine such as described in DE-A-2 001 543 or GB-A-2 058 663. The single facer comprises a top roll having teeth 1a formed around the circumferential surface thereof and arranged for free rotary movement, a lower roll having teeth 2a formed around the circumferential surface thereof and arranged for free rotary movement with teeth 2a being engaged teeth of the top roll so that a corrugating medium 5 may be shaped into a corrugated configuration by urging the medium to enter into a gap to be formed between teeth 1a and 2a, a gluing roll 3 arranged closely adjacent to the teeth 2a of the lower roll 2 for rotary movement and is adapted to apply a predermined quantity of glue over the wavy-shaped top portion of the corrugating medium 5 which has been formed, and a press roll 4, arranged to be closely adjacent to or in contact with the teeth 2a of the lower roll 2 for rotary movement and being adapted to produce a single faced corrugated board by allowing the corrugating medium 5 with glue applied and the liner board 6 to pass between it and the lower roll 2 under pressure for lamination. Gaps to be formed between the top roll 1 and the lower roll 2, between the lower roll 2 and the gluing roll 3 and between the lower roll 2 and the press roll 4 are all made to be variable in dimensions by means of an apparatus for adjusting the roll contacting pressure (clearance), i.e., an apparatus for adjusting a distance between the centers of roll shafts. In such a single facer, suitable urging forces and heating means of the glues must be provided to laminate the corrugating medium 5 with the liner board 6 by applying glues, and consequently an apparatus for withdrawing (circulating) steam to supply heating energy is incorporated in said rolls 1, 2 and 3. There was a problem as described below in the traditional single facer illustrated in Fig. 1. That is, when a glue is used to laminate the liner board 6 with the corrugating medium 5 which has been formed in a wavy-configuration, a certain heating means is required to heat the starch glue to a flowable state, and hot rolls which has been heated act to elevate the temperature and expand the opposite sides frames 8 on which rolls are supported. This results, for example, in the increase of the distance P between the centers of shafts of lower and press rolls 2 and 4 which are journaled, and consequently a gap amount S also tends to increase with time. For these shortcomings, urging forces of the press roll 4 are gradually reduced, and such small urging forces may result in the production of the single faced corrugated fiberboard 7 with inconsistent thickness and also in an imperfectly laminated corrugating medium 5 and the liner board 6 from which the single faced corrugated fiberboard sheet are made, and thus a poor quality paper has frequently be made having substantially reduced strength and quality. The problem in the prior art has been described with reference to the lower roll 2 and the press roll 4, but similar problem of varying the distance between the centers of roll shafts may also occur between the top roll 1 and the lower roll 2, or between the lower roll 2 and the gluing roll 3, as the temperature of the frame 8 is elevated, and this has been a significant factor to block the improvement of the apparatus toward automation. Therefore, it has been a common practice to check the corrugated fiberboard 7 which is being produced for any abnormality through a visual inspection, and then to manually remove any defect if any. This procedure, however, needs a high level of skills and experiences, which blocks automation. OBJECT AND SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a single facer which can maintain a gap between rolls at constant by automatically correcting a distance between the centers of roll shafts. The above object is achieved by providing a single facer comprising the features of claims 1 and 2. Thus, the inventor of the present invention has found that the temperature of the frame is increased with time as hot steam is caused to circulate within each of rolls, and that there is a certain interrelationship between the temperature of the frame and the gap amount of the lower roll. When the steam valve is opened, the temperature of the frame may increase in a curved fashion, and the gap amount between said rolls may also increase proportionally. It is also found that the temperature of the frame may cease increasing further at a predetermined time and therefore the temperature is kept at a constant level, and the gap amount become steady after the passage of the predetermined time. Such tendency has been substantially common to the same single facer. Taking the above phenomenon (tendency) into account, the present invention has been made such that a temperature sensor is utilized to measure the temperature variation of the frame, and an apparatus is driven via a controller for correcting the distance between centers of roll shafts so as to maintain a gap amount at a constant level. Furthermore, because the temperature increase of the frame may be taken as a function of the passage of time, a timer is preset so that the apparatus for correcting the distance between the centers of roll shatfs may be actuated in response to the passage of the preset time, instead of the variation in the frame temperature, and thereby maintaining the gap amount between rolls at constant. As afore-described, the present invention is constituted such that the variation in the distance between the centers of roll shafts may be detected either as a function of the passage of time or by directly measuring the frame temperature, and the apparatus for correcting the distance between the centers of the roll shafts may be controlled in response to such temperature variation, and thus a precise correction is achievable for the expansion (increase in the gap amount between the lower roll and the press roll and the like). As a result, it is possible to eliminate inconsistent lamination between single faced corrugated fiberboard sheets and the like, providing a remarkable effect in the improvement of the product quality such as thickness, strength and aesthetical appearance etc., moreover, it is not needed to stop operating the single facer to adjust the contact pressure between rolls, and besides numerous other merits are derived such as an automatic operation. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a concentional view showing a typical single facer in a prior art; Fig. 2 is a lateral cross-sectional view showing the single facer embodying the concept of the present invention; Fig. 3 is a partial cross-sectional view showing a press roll section in the single facer in accordance with the present invention; Fig. 4 is a front elevation showing essential parts of the apparatus for adjusting a distance between the centers of the shafts of the press roll and the lower roll; Fig. 5 is a diagrammatic view showing a relationship between the passage of time after hot steams are caused to circulate in each of rolls, the gap amount between rolls and the frame temperature; and Fig. 6 is a view showing an alternative mode of operation of the apparatus for adjusting the distance between the centers of the roll shafts. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS A single facer is constituted as shown in Fig. 2 by a top roll 11 having teeth 11a formed around the circumfernetial surface, a lower roll 12 having teeth 12a formed around the circumferential surface with said teeth 12a engaged teeth 11a of the top roll 11, a gluing roll 13 arranged to be closely adjacent to teeth 12a of said lower roll 12, and a press roll 14 and the like arranged to be closely adjacent to or in contact with teeth 12a of the lower roll 12. The lower roll 12 has its bearings pinched and fastened in place between the frame 15 and the bracket 16. The top roll 11 is supported via bearings (not shown) on an arm 17 one end of which is attached to the frame via a pivot pin 18 for free pivotable movement and an opposite end of which is coupled with the piston rod tip end of the pressure cylinder via a pin 20. The pressure cylinder 19 is supported on the bracket 16 which is in turn fastened with the frame 15. A positioning stop (not shown) is used in conjunction with the cylinder 19 to adjust a contacting pressure (gap) between two rolls 11 and 12. As shown in Fig. 3, the shaft 14a of the press roll 14 is journaled on bearings 22 opposite ends of which are embraced by an eccentric disc 21 which is held on the frame 15 via a bush 23 for pivotal movement. A press lever is secured via a tapered pin 24 on the eccentric disc 21. An eccentricity adjustment rod 26 is provided to be closely adjacent to one end of the press lever 25. As shown in Fig. 4, the eccentricity adjustment rod 26 has its opposite ends journaled on the frame via a slide bush 27 for axial slidable movement. Furthermore, a female thread 26a is formed on an outside end of the said rod 26 and threadably engaged with a thread rod 28. A portion of the thread rod 28 is journaled on the bracket 39 through bearings 29 and the top end of the rod 28 is directly coupled through a coupling 32 with the shaft 31a of the motor 31 which is secured on the bracket 32. The motor 31 is controlled as described below in response to the temperature sensor 33 provided on the frame 15, and connected with the temperature sensor 33 through the controller 34. An inclined slider 35 is secured in place on said rod 26 where it corresponds with the bearing section of the press roll 14, and as the rod 26 slides in an axial direction the press lever 25 and the eccentric disc 21 are caused to pivot by means of the slider 36 which is in sliding contact with the inclined surface 35a of the slider 35, and thereby shifting the position of the center c of the press roll shaft 14a. A cylinder 37 for securing the eccentric disc is arranged between an opposite end of the press lever 25 and the frame 15 as shown in Fig.3. The cylinder 37 urges the press lever 25 towards a counterclockwise direction in Fig.3. Thus, the slider 36 which is arranged on one end of the press lever 25 is constantly in abutment with the slider 35. The shaft 13a of the gluing roll 13 is supported on the frame 15 or an arm and the like via bearings. The gluing roll 13 has its lower portion oriented toward and immersed in a glue 39 in a glue container 38. An adjustment roll 40 is arranged above the glue container 38. The adjustment roll 40 functions to suitably adjust the quantity of glues 39 adhered on the gluing roll 13 surface, and has its shaft 40a supported for movement on the frame 15 or an arm and the like via bearings and its circumferential surface in abutment with the gluing roll 13 to scrape away an excess glue 39 adhered on the roll 13. In such single facer, a single faced corrugated fiberboard sheet is manufactured in accordance with a process wherein the corrugating medium 41 is urged to enter into a gap between rolls 11 and 12, and formed into a corrugated shape under cooperation between two rolls 11 and 12, then the corrugating medium 14 is guided to pass through rolls 12 and 13, glue 39 is applied over the top portion of the corrugating medium 41 by means of the roll 13, furthermore the corrugating medium 41 and the liner board 41 are overlapped each other between rolls 12 and 14, and finally the liner board 42 is urged against the corrugating medium 41 by means of the roll 14. During the course of this process, steam is supplied to rolls 11,12 and 14 through valve 44 with the actuation of the single facer, and this steams acts to heat rolls 11, 12 and 14. As these rolls 11, 12 and 14 are elevated in temperature, the heat is transmitted to the frame 15 through bearings and the like. In this manner, as the temperature of the frame 15 increases, the frame 15 is expanded in response to such heat, and as a result distances P between rolls 11 and 12 and between rolls 12 and 14 increase. Fig. 5 indicates an interrelationship between the frame temperature T which is variable with the passage of time after hot steam is caused to circulate in rolls 11, 12 and 14 and the gap amount S between the lower roll 12 and the press roll 14. In this graphical illustration, it is indicated that when the steam valve is opened at the time Ha, the temperature of the frame 15 is increased from Ta to Tb after a predetermined period is expired as shown with a solid line, and proportionally the gap amount between said rolls is increased from Sa to Sb. In the meantime, the temperature increase of the frame 15 reaches its peak value after the predetermined time H b and then the temperature stops elevating further and thereafter a constant temperature T b is maintained and the gap amount S between rolls is also maintained at constant after the expiry of the predetermined time H b . This tendency is substantially common to the same single facer. In the above embodiment, the phenomenon (tendency) is taken into account, and the temperature sensor 33 is used to measure the temperature variation of the frame 15 and then the controller is actuated to drive the motor 31 in accordance with the temperature thus measured, and thereby maintaining the gap amount S between rolls 12 and 14 constant. From the graphical illustration in Fig. 5, it is shown that it is possible to take the temperature increase of the frame 15 as a function of the passage of time from Ha to Hb. Thus, as shown in Fig. 6, the gap amount S between the lower roll 12 and the press roll 14 can be maintained constant by providing the valve 44 with the sensor 33' adapted to verify the opening of the valve 44, and the output from the sensor 33' is supplied to the controller 34' in which the motor 31 is actuated to operate in accordance with the amount which corresponds to the passage of time in Fig. 5. The broken line in Fig. 5 represents a curve indicating one example of how variations in the gap may be corrected, and such correcting amount may be freely preset through controllers 34 and 34'. In the embodiment described above, the apparatus for correcting the distance between the centers of the roll shafts in accordance with the present invention is provided between the lower roll 12 and the press roll 14, but it is also possible to arrange the same apparatus between the lower roll 12 and the top roll 11 and between the lower roll 12 and the gluing roll 13.

Claims: In a single facer apparatus for forming a single-faced corrugated web (43), the apparatus comprising a top corrugating roll (11), a lower corrugating roll (12), a gluing roll (13) and a press roll (14), all supported on a frame (15), and heating means for heating each of said rolls, the improvement comprising: means for adjusting (19,20,37) the distance between the centers of the shafts of said lower corrugating roll (12), said top corrugating roll (11), said gluing roll (13), and said press roll (14); temperature sensor means (33) for detecting the expansion of said frame (15) caused by transfer of heat from said rolls by detecting the temperature of said frame; and means (31) for actuating said means for adjusting in response to the detection of expansion of the frame by said temperature sensor means in order to compensate said expansion of said frame by maintaining the distance between said centers of support shafts constant. In a single facer apparatus for forming a single-faced corrugated web (43), the apparatus comprising a top corrugating roll (11), a lower corrugating roll (12), a gluing roll (13) and a press roll (14), all supported on a frame (15), and heating means for heating each of said rolls, the improvement comprising: means for adjusting (19,20,37) the distance between centers of support shafts of said lower corrugating roll (12) and said top corrugating roll (11), said gluing roll (13) and said press roll (14); sensor means (33) for detecting the expansion of said frame (15) as a function of a predetermined time interval from the initiation of operation of said heating means until the time said frame has reached a substantially constant elevated temperature level; and means (31) for actuating said means for adjusting in response to the detection of expansion by said sensor means in order to compensate said expansion of said frame by maintaining the distance between said centers of support shafts constant.

Inventors: MURAYAMA KIMIO C O MIHARA MACH, SASASHIGE HIROAKI C O MIHARA M, SEKI YUKUHARU C O MIHARA MACHI, MURAYAMA, KIMIO, SASASHIGE, HIROAKI, SEKI, YUKUHARU, MURAYAMA, KIMIO, C/O MIHARA MACHINERY WORKS, SASASHIGE, HIROAKI, C/O MIHARA MACHINERY WORKS, SEKI, YUKUHARU, C/O MIHARA MACHINERY WORKS
Applicants: MITSUBISHI HEAVY IND LTD, MITSUBISHI JUKOGYO KABUSHIKI KAISHA
Application year: 1990
Main classification: B31F1
IPC codes: B31F1