PRESS ROLL ELEVATOR IN A DOUBLE FACER

Abstract: The known press roll elevator in a double facer in the prior art of the type that there are provided press roll groups, in each of which press rolls for a corrugated cardboard sheet rotatably supported between tip end por­ tions of respective pairs of arms adapted to swing in the traveling direction of the sheet about fulcrum shafts on the both side frames of the double facer, are disposed at intervals along the traveling direction of the sheet, and the press rolls are elevated and lowered by swing motion of the aforementioned arms, is improved in order to facilitate adjustment and other maintenance works for the press roll elevator. The improvements reside in that common rails adapted to be reciprocated along the travel­ ing direction of the sheet and associated with protrusions which butt against the respective arms to swing them, are provided, and differences between the fulcrum intervals between the respective fulcrum shafts and the protrusion intervals between the corresponding intervals are succes­ sively varied in the traveling direction of the sheet.

Description: BACKGROUND OF THE INVENTION: Field of the Invention: The present invention relates to an elevator for press rolls disposed in a heating part or the like of a double facer in a corrugate machine. Description of the Prior Art: In a heretofore known double facer of the above-described type, as shown in Fig. 4, a single-faced corrugated cardboard sheet a having starch applied to its flute tips by means of a glue machine 1 (See Fig. 5) and a liner b preliminarily heated by a preheater 2 (See Fig. 5) are carried in and take a laminated state, the above-mentioned both sheets a and b are conveyed as pinched between a heating box 4 on the lower side and a canvas belt 3 on the upper side (3a denoting a drive pulley) in a heating part 10a, and in a cooling part 10b they are conveyed as pinched between the canvas belt 3 on the upper side and a conveyor belt 5 stretched between pulleys 5a and 5b. They are applied with pressing forces from the upper side via the canvas belt 3 by a large number of press rolls 9 which are disposed as spaced in the traveling direction of the sheets and ascend and descend, then in the heating part 10a the starch is made to gel by heating of the respective heating boxes 4, resulting in a bonded and joined double-faced corrugated cardboard sheet a, b, and after they have been cooled and regulated in nature (correction of warp deformation or the like) in the cooling part 10b, they are carried out to the next step of the process. The above-mentioned respective press rolls 9 are rotatably supported between connecting shafts 25 via bearings 23a, which connecting shafts 25 are supported from air cylinders 21 at the top of the both side frames 10 of the double facer by the intermediary of yokes 22, pins 23 and bearings 24, thereby there is provided a press roll elevator in which the press rolls 9 are elevated or lowered and the sheets are pressed via the canvas belt 3 by the respective press roll 9 disposed at an interval in the traveling direction of the sheets. The pressing forces are useful for promoting the heating in the heating part 10a and also for surely conveying the sheet by increasing a frictional force between the canvas belt 3 and the corrugated cardboard sheet. It is necessary to set an appropriate pressing force such that it does not crush the flute tips, and with regard to the strength required for the pressing force, it is necessary to make the strength adapted to the conditions such as a manufacturing speed of the double-faced corrugated cardboard sheet a, b (a sheet traveling velocity), specifications (material and paper sheet thickness) of the raw material paper sheets for the corrugated cardboard sheet, types and combinations of flutes of the corrugated cardboard sheet, working environment (room temperature or the like), and the like. The above-described press roll elevator shown in Fig. 4 has such structure that the rolls 9 are elevated by feeding pressurized air to a pair of air cylinders 21 provided for each press roll 9 to be made inactive, or on the contrary the air cylinders 21 are made to be inactive for allowing the rolls 9 to descend due to their own weight and thereby the above-mentioned pressing force is applied, and the elevator has a characteristic feature that a number of operative press rolls 9 can be selectively pre-set for adjusting over-drying or insufficient heating of the sheet which varies depending upon various conditions such as specifications of the sheet, machine speeds and the like. Whereas, in the press roll elevator in the prior art shown in Fig. 5, in a heating part 10a press rolls 9 are rotatably supported between top end portions of respective pairs of arms 12 which are pivotably supported from the both side frames 10, the press rolls 9 are disposed at an interval in the traveling direction of the sheet, and respective protrusions 16 on rails 15 which are reciprocated along the traveling direction of the sheet are held in contact with the lower portions of the respective arms 12 to swing the arms 12. These rails 15 are reciprocated by means of geared motors or the like via wheels, screw shafts 17, and the like, hence the respective press rolls 9 are synchronously raised as a whole by the reciprocating motions of the respective rails 15 and descend due to their own weights, and thereby pressing forces are applied to the sheet. In addition, in a cooling part 10b, the construction that respective arms are disposed so as to be swingable about fulcrum shafts on the both side frames 10 and the respective press rolls are actuated to ascend and descend through a mechanism similar to that described above, is formed, the thicknesses of the single-faced corrugated cardboard sheet a and the liner b are detected. The above-described rails 15 are controlled in response to that detection signal, thus the pressing forces of the respective press rolls 9 are adjusted as a whole, and the gap distance between the canvas belt 3 and the heating box 4 can be appropriately adjusted depending upon the thickness of the corrugated cardboard sheet. Among the above-described press roll elevators in the prior art, in the example of the prior art shown in Fig. 4, the adjustment for individually elevating and lowering the respective press rolls while holding them in parallel to the top surface of the heating box is difficult because the both ends of the respective press rolls are elevated and lowered by actuating the respective air cylinders, in some cases the press rolls would descend at an inclined state and would partly crush the flute tips of the corrugated cardboard sheet, and as a counter-measure for preventing such accident it is necessary to additionally provide a sheet flute crush preventing device such as stoppers for the press rolls which can be adjusted in correspondence to the thickness or the like of the corrugated cardboard sheet. Also, a large number of air cylinders and electromagnetic valves for control purpose are necessitated, hence troubles such as seizure of a coil in the electromagnetic valve or faulty operations caused by dust or the like entered in the piping, are liable to occur, furthermore, pneumatic machines such as compressors or the like and various relevant equipments such as air pipings or the like become necessary, and so, the structure becomes complicated and expensive in cost. In the example of the prior art shown in Fig. 5, since the respective arms for supporting the respective press rolls are disposed on the upper side as well as on the lower side of the corrugated cardboard sheet, and also since the respective arms and the respective press rolls are synchronously elevated and lowered as a whole at the same time, it is impossible to adjustably control the pressing forces in correspondence to the conditions (traveling speed, sheet thickness, etc.) of the corrugated cardboard sheet, also difficulties would accompany the work of removing starch dregs sticking to the upper surface of the heating box and cleaning the surface, and so, there exists the problem that the work takes too much time and the rate of operation (productivity) of the machine is lowered. SUMMARY OF THE INVENTION: The present invention has been developed in order to deal with the above-mentioned problems in the prior art, and one object of the present invention is to provide an improved press roll elevator in a double facer, in which horizontality of the respective press rolls is assured, also the respective press rolls in a press roll group are elevated and lowered in successively different phases, thereby an adjusting performance of pressing forces and a workability for inspection and maintenance are enhanced, a sticking performance and a reliability are improved, and a rate of operation as well as a productivity are raised. According to one feature of the present invention, there is provided a press roll elevator including press roll groups in each of which press rolls for a corrugated cardboard sheet rotatably supported between tip end portions of respective pairs of arms adapted to swing in the traveling direction of the sheet about fulcrum shafts on the both side frames of the double facer, are disposed at intervals along the traveling direction of the sheet, and the above-mentioned press rolls are elevated and lowered by swing motion of the aforementioned arms, characterized by the construction that common rails adapted to be reciprocated along the traveling direction of the sheet and associated with protrusions which butt against the aforementioned respective arms to swing them are provided, and differences between the fulcrum intervals between the above-mentioned respective fulcrum shafts and the protrusion intervals between the corresponding protrusions are successively varied in the traveling direction of the sheet, whereby the respective press rolls can be elevated and lowered while maintaining their horizontality by swinging the respective arms with the respective protrusions on the common rails reciprocating in the traveling direction of the sheet butted against them, the elevated positions of the respective press rolls are successively varied owing to the fact that the differences between the fulcrum intervals between the respective fulcrum shafts and the protrusion intervals between the corresponding protrusions are successively varied in the traveling direction of the sheet, thus adjustment of the pressing forces is made to be possible, and also the works of inspection, maintenance and the like are facilitated. According to the present invention, as a result of the reciprocating motion of the common rails, the respective arms would butt against the respective protrusions on the common rails and thereby would be made to swing, thus the respective press rolls are actuated to be elevated and lowered, the respective press rolls can rise and fall as held horizontally owing to the synchronous swinging of the respective pairs of arms at the opposite end portions of the respective press rolls caused by the above-mentioned protrusions, hence the pressing forces applied to the sheet are equalized along the widthwise direction of the sheet, furthermore the respective press rolls in the press roll group are subjected to successively varied elevating and lowering operation owing to the fact that the differences between the fulcrum intervals between the respective fulcrum shafts and the protrusion intervals between the corresponding protrusions are successively varied in the traveling direction of the sheet, thus the pressing forces applied by the press roll group can be adjusted, and the works of dealing with troubles such as a damaged liner sheet or the like, removing starch dregs and the like, can be achieved easily and quickly. The above-mentioned and other objects, features and advantages of the present invention will become more apparent by reference to the following description of preferred embodiments of the invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS: In the accompanying drawings: Fig. 1(A) is a side view showing a first preferred embodiment of the present invention; Fig. 1(B) is a cross-section view taken along line Ib - Ib in Fig. 1(A); Fig. 1(C) is a cross-section view taken along line Ic - Ic in Fig. 1(A); Fig. 2(A) is an enlarged side view of the portion of a press roll group in Fig. 1(A); Fig. 2(B) is a schematic view showing a position control mechanism on the common rail in Fig. 2(A); Fig. 3 is an enlarged side view of the portion of a press roll group according to a second preferred embodiment of the present invention; Fig. 4(A) is a side view showing one example of a press roll elevator in the prior art; Fig. 4(B) is a cross-section view taken along line IV - IV in Fig. 4(A); Fig. 5(A) is a side view showing another example of a press roll elevator in the prior art; and Fig. 5(B) is a cross-section view taken along line V - V in Fig. 5(A). DESCRIPTION OF THE PREFERRED EMBODIMENTS: Referring now to Figs. 1 and 2 which illustrate a first preferred embodiment of the present invention, reference character a designates a single-faced corrugated cardboard sheet having starch applied to its flute tips, character b designates a liner that has been preliminarily heated by a preheater 2, numeral 3 designates a canvas belt disposed on the upper side of a heating part 10a and a cooling part 10b and driven by a drive pulley 3a, numeral 4 designates a plurality of heating boxes disposed on the lower side of the heating part 10a, numeral 5 designates a conveyor belt disposed on the lower side of the cooling part 10b and driven by pulleys 5a and 5b. In the illustrated press roll elevator in a double facer, there are provided press roll groups, in each of which press rolls 9 rotatably supported between lower portions of respective pairs of arms 32 adapted to swing in the traveling direction of the sheet about fulcrum shafts 31 at the upper portions of the both side frames 10 of the double facer, are disposed at intervals in the traveling direction of the sheet, and the press rolls 9 are elevated and lowered by swing motion of the arms 32. Furthermore, there are provided common rails 35 adapted to be reciprocated along the traveling direction of the sheet and associated with protrusions 36 which butt against the respective arms 32 to swing them, and as compared to the fulcrum intervals p between the respective fulcrum shafts 31, the respective protrusion intervals ( p + α), ( p + β) and ( p + γ) are relatively varied to establish different pitches which are successively varied in the traveling direction of the sheet. As shown in Figs. 1(A) and 1(C), the above-mentioned common rails 35 are disposed on the both side frames 10 on the respective sides of the double facer to be reciprocated in the axial direction, that is, in the traveling direction of the sheet, as slidably supported by a plurality of rail pedestals 34, so that respective protrusions 36 projected from the common rails 35 butt against the lower sides of the middle portions of the respective arms 32 and cause the arms 32 to swing, and thereby the respective press rolls 9 are elevated and lowered. As shown in Figs. 1(A) and 1(B), worm wheels 38 supported by brackets 39 on the respective side frames 10 are threadedly engaged with screw rods 37 connected to the end portions of the common rails 35, a worm 41 fixedly fitted around a drive shaft 40 that is rotatably supported between the respective side frames 10, is meshed with the worm wheel 38, and the common rails 35 are reciprocated via the worms 41, the worm wheels 38 and the screw rods 37 by normally or reversely driving the drive shaft 40 via a shaft coupling 44 by means of a geared motor 43 on a bracket 42. Furthermore, as shown in Fig. 2(A), in contrast to the fact that the respective fulcrum intervals p between the respective fulcrums 31 at the top ends of the respective arms 32 are chosen to be the same length, the respective protrusion intervals between the respective protrusions 36 projected from the respective common rails 35 are varied and set at ( p + α), ( p + β) and ( p + γ), respectively, so as to establish successively different pitches, in the illustrated embodiment the above-mentioned variation in the protrusion intervals are repeated for every press roll group consisting of three press rolls. In response to leftward movement as viewed in Fig. 2 of the common rails 35, the press rolls 9''', 9'' and 9' are raised by successively different heights in the enumerated sequence, while in response to rightward movement as viewed in Fig. 2 the press rolls are lowered by successively different heights in the sequence of 9', 9'' and 9''', so that the pressing forces can be adjusted by the amount of movement of the common rails 35. In addition, as shown in Fig. 2(B), an actuator piece 45 is fixedly secured to the common rail 35, and along the route of movement of the actuator piece 45 are disposed limit switches 46A, 46B, 46C and 46D as opposed to the actuator piece 45. The detection signals issued from the respective limit switches in response to detection of the actuator piece 45 are fed back to the geard motor 43 for drive control purpose (drive or stoppage), thus the operation position control for the common rail 35 is effected in such manner that upon actuation of the limit switch 46D all the press rolls are lowered and take operative positions, upon actuation of the limit switch 46A only the press roll 9''' is elevated to an inoperative position, upon actuation of the limit switch 46B the press rolls 9''' and 9'' are elevated to inoperative positions, and upon actuation of the limit switch 46C all the press rolls are elevated to inoperative positions, and owing to the above-described control, adjustment of the pressing forces generated by the group of press rolls 9', 9'' and 9''' can be achieved in various ways, and depending upon various conditions such as a sheet manufacturing speed (sheet traveling speed), specifications (materials and thicknesses) of the raw material paper sheets of the corrugated cardboard sheet, types and combinations of flutes of a corrugated cardboard sheet, working environment, etc., the adjustment is varied for each press roll or for each press roll group. The number of rolls in the above-described roll group is appropriately increased or decreased according to the manufacturing conditions of the corrugated cardboard sheet, and with regard to the position detector means for the common rail 35, besides the limit switches, approach switches, photo-electric tubes or the like are available. Now explaining the operation of the first preferred embodiment of the present invention having the aforementioned construction, a single-faced corrugated cardboard sheet a applied with starch and a preheated liner b are carried in and superposed, in the heating part 10a the superposed sheets a and b are pinched between the upper surfaces of the respective heating boxes on the lower side and the canvas belt 3 on the upper side and conveyed thereof, subsequently in the cooling part 10b they are pinched between the conveyor belt 5 on the lower side and the canvas belt 3 on the upper side and conveyed thereby, also pressing forces are applied thereto by the press rolls 9 via the canvas belt 3, they are heated and joined into a double-faced corrugated cardboard sheet a , b in the heating part 10a, and in the cooling part 10b they are cooled and subjected to rectification for warps and the like, and then they are carried out to the next step of the process. The above-described common rails 35 are reciprocated along the traveling direction of the sheet by the geared motor 43, the respective arms 32 are made to swing by the above-mentioned reciprocating motion, hence the respective press rolls in the press roll group are elevated and lowered, thus the press rolls 9 are made to be inoperative by being elevated or made to be operative for applying pressing forces by being lowered. The swingings of the respective pairs of arms 32 at the respective ends of the respective press rolls 9 are synchronized by the common rails 35, the respective press rolls 9 are elevated and lowered as held horizontally, the pressing forces applied to the both sheets a and b by the respective press rolls 9 are equalized along the widthwise direction of the sheets, and thereby partial crushing of the flute tip portions can be prevented. In addition, owing to the fact that as compared to the respective fulcrum intervals p between the respective fulcrum shafts 31 in the press roll group, the respective protrusion intervals ( p + α), ( p + β) and ( p + γ) are set at relatively different values so as to establish successively different pitches, by controlling the reciprocated position of the common rails 35, among the press rolls in the press roll group the number of press rolls 9 which are elevated and lowered to apply pressing forces can be adjustably increased or decreased, that is, adjustment of the pressing forces can be arbitrarily effected, and so, a joining performance and a reliability of the double-faced corrugated cardboard sheet can be improved. Furthermore, since the respective press rolls 9 are elevated by successively different heights, counter-measure for troubles such as damage of the liner or the like, or the work of removing starch dregs sticked onto the heating box 4 as a result of projection of the width ends of the sheet, can be achieved easily and quickly, hence in addition to improvements in safety of the aforementioned work, a rate of operation and a productivity of the machine can be enhanced. Also there exist advantages such that the structure is simplified, and so, a running cost including maintenance parts, inspections and repairs, can be saved. A second preferred embodiment of the present invention is shown in Fig. 3. As compared to the above-described first preferred embodiment, the second embodiment is characterized by the construction such that while the respective protrusion intervals between the respective protrusions 36' projected from the common rails 35 are chosen to be the same value p , the respective fulcrum intervals between the respective fulcrum shafts 31' which pivotably support the upper end portions of the respective arms 32' are relatively varied and set at (p - α), (p - β) and (p - γ), respectively, to establish successively different pitches along the traveling direction of the sheet. Even with such modified construction, swinging of the respective arms 31' caused by the respective protrusions 36' on the common rails 35 and the elevating and lowering actions thereof for the respective press rolls 9 are substantially the same, and so, effects and advantages similar to those of the first preferred embodiment can be obtained. As will be apparent from the detailed description of the invention in connection to preferred embodiments thereof, owing to the above-described characteristic feature of the invention, the respective pairs of arms at the opposite ends of the respective press rolls are made to swing synchronously by the respective protrusions on the common rails reciprocating along the traveling direction of the sheet, hence the respective press rolls are elevated and lowered while maintaining their horizontality, thus the pressing forces applied to the corrugated cardboard sheet by the respective press rolls can be equalized along the widthwise direction of the sheet, partial crushing of the flute tip portions can be prevented, also by controlling the reciprocating positions of the common rails, the pressing forces by the press roll group can be adjusted, and a joining performance as well as a reliability are remarkably improved. In addition, since the respective press rolls are elevated by successively different heights by the common rails, workabilities of counter-measure for troubles such as damage of a liner or the like and removal of starch dregs on the upper surfaces of the heating boxes can be enhanced, hence a rate of operation and a productivity are increased, and also, additional advantages such as simplicity in a mechanism and saving of a running cost are obtained.

Claims: A press roll elevator in a double facer including press roll groups, in each of which press rolls (9) for a corrugated cardboard sheet rotatably supported between tip end portions of respective pairs of arms (32) adapted to swing in the traveling direction of the sheet about fulcrum shafts (31) on the both side frames of the double facer, are disposed at intervals along the traveling direction of the sheet, and said press rolls are elevated and lowered by swing motion of said arms; characterized in that common rails (35) adapted to be reciprocated along the traveling direction of the sheet and associated with protrusions (36) which butt against said respective arms to swing them, are provided, and differences between the fulcrum intervals between said respective fulcrum shafts and the protrusion intervals between the corresponding protrusions are successively varied in the traveling direction of the sheet. A press roll elevator in a double facer as claimed in Claim 1, characterized in that the fulcrum intervals between the respective fulcrum shafts of the arms are chosen to be the same length, and the protrusion intervals between the respective protrusions on the common rails are successively varied in the traveling direction of the sheet. A press roll elevator in a double facer as claimed in Claim 1, characterized in that the protrusion intervals between the respective protrusions on the common rails are chosen to be the same length, and the fulcrum intervals between the respective fulcrum shafts of the arms are successively varied in the traveling direction of the sheet.

Inventors: ISHIBASHI, YOSHIMITSU C/O MIHARA MACHINERY WORKS
Applicants: MITSUBISHI JUKOGYO KABUSHIKI KAISHA
Application year: 1989
Main classification: B31F1
IPC codes: B31F1