Patent Publication Number: US-6708919-B2

Title: Turning bar assembly for use with a moving web

Description:
BACKGROUND OF THE INVENTION 
     Turning bars for use in a system for manufacturing and processing web material are known. Typically, these known turning bars are found in a web manufacturing machine to turn or redirect a moving web from one direction to another; i.e., to direct the moving web to a finishing station away from the machine direction and then redirect the finished web toward the machine. 
     The typical turning bar is a unitary component fixed relative to the web manufacturing machine. Since it is fixed and does not rotate, at least one drawback to the known turning bar is that dust accumulates on the turning bar, particularly in the manufacture of a paper web material such as tissue paper. Dust accumulation and subsequent dust clumping on the turning bar have the potential to adversely affect the quality of a finished product, as well as system or machine runnability if the dust accumulates and subsequently falls into the product, for instance, during packaging. 
     Dust clumping occurs, for example, when the standard fixed turning bar generates static electricity. The non-rotating turning bar thus attracts and holds dust during operation of the system. When the system is even momentarily stopped, dust clumps, which have been held to the turning bar by static electricity, fall into the product, which leads to degraded product quality and consumer dissatisfaction. 
     Attempts to address the dust accumulation problem include use of compressed air to blow dust off the web before it accumulates on the turning bar or elsewhere. By way of example, a Coanda nozzle is described in U.S. Pat. No. 5,577,294 to Pollock for a “Web Cleaner Apparatus and Method.” In Pollock, the Coanda nozzle directs a gas flowing at a high rate of speed in a direction generally opposed to the moving web of sheet material for cleaning a substantially planar surface of the moving web material. 
     In addition to Pollock, a variety of other air nozzle configurations and area dust containment and removal systems have been tried over the years to address the problems of dust accumulation and clumping. In general, however, compressed air and similar methods tend to create environmental dust problems in a web machine&#39;s operating area, which may require workers to don protective masks for respiratory protection and may necessitate costly air-scrubbers to control the blown dust. Accordingly, many previous dust accumulation prevention techniques and apparatuses have tended to increase manufacturing and consumer costs with debatable success. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is directed to a turning bar assembly rotatably disposed adjacent a web of material moving at an operational speed in a web forming device. The component parts of the invention are simple, reliable, and economical to manufacture, assemble, and use. Other advantages of the invention will be apparent from the following description and the attached drawings or can be learned through practice of the invention. 
     According to an aspect of the invention, a turning bar assembly is rotatably disposed adjacent a web of material moving at an operational speed of approximately 12-13% of the web speed in a web forming device. The relative speed of 12-13% is provided by way of example only, since the turning bar assembly can be controllably rotated relative to the web at any speed at least less than the speed of the web. 
     The turning bar assembly includes a roller or a turning bar, which receives, turns and transfers the web down or across stream in the web forming device. For instance, the turning bar may be oriented at 45° to the moving web and when the web contacts the turning bar, the direction of the web is changed 90°. Such redirection or sheet turning by the turning bar may be desirable, for instance, if the web is to be finished at a finishing station located away from the longitudinal direction of the web forming device. Upon finishing the web, another turning bar assembly may be provided downstream to further redirect the web. 
     The turning bar in one aspect of the invention has a first and a second end. A first mounting end or first mount is attached to the first end and a second mounting end or second mount is attached to the second end. The first end is disposed apart from the second end at a distance of between ten to about forty inches, and an outer diameter of the turning bar is between one inch to about three inches to accommodate the standard web material dimensions. It is within the scope of the invention that the length and the outer diameter of the turning bar can be increased or decreased. Also in this aspect, the turning bar is configured to be controllably rotated 360 degrees relative to the first and second mounts at a speed less than the operational speed of the moving web, such as 1-50% of the web speed, or more specifically 10-20% of the web speed. Web speed can be calculated in a variety of ways and be within the scope of the invention. 
     According to another aspect of the inventive turning bar assembly, a central or center shaft is disposed longitudinally within the turning bar and fixed to the first and second mounts. In this arrangement, the turning bar is rotatably disposed about the shaft. The turning bar and shaft combination is configured to be removable from the assembly for maintenance and replacement. 
     In further detail, the turning bar assembly in this aspect includes a plurality of bearings rotatably disposed within the turning bar and about the shaft. The turning bar and the plurality of bearings cooperate to rotate at substantially the operational speed of the moving web. Although the shaft described herein is a unitary shaft extending substantially the length of the turning bar, it is contemplated that the shaft could be formed in multiple pieces. For instance, those portions of the shaft attached to the first and second ends could be severed and apart from each other such that the separate shaft portions extend into the turning bar a sufficient length to support a bearing assembly and be within the scope of the invention. 
     This aspect also includes a drive apparatus operably connected with the turning bar to rotate the turning bar between about {fraction (1/100)} to about ⅕ of the operational speed of the moving web. The drive apparatus may include in one embodiment a rod or drive shaft, a drive belt, and a motor or other control mechanism. The drive belt is disposed about a portion of the turning bar and a portion of the rod. The drive belt rotates the turning bar when the rod is rotated by the motor. It is to be noted that a single drive shaft could extend the length of the web-forming device with a plurality of drive belts depending from the single drive shaft and operably connected to a plurality of turning bars. Alternatively, it is contemplated that each of the plurality of turning bars could be controllably rotated by individual drive shafts and drive belts or other independent drive mechanisms and remain within the invention&#39;s scope. 
     In another aspect of the invention, a web forming system is provided, which has a turning bar assembly disposed adjacent a moving web similar to the foregoing embodiment. In this aspect, at least one bearing assembly is disposed concentrically about the shaft within the turning bar. The bearing assembly is configured to allow the turning bar to rotate about the shaft and includes a plurality of bushings and bearings to rotatably attach the turning bar about the shaft. The bushings may be bronze bushings, phenolic bushings, or of other suitable materials to adapt the first and second ends to the shaft. 
     Once mounted in the web-forming device, the bushings and bearings permit the turning bar to continuously change an aspect or a portion contacting the moving web. Due to this controlled rotation, the dust is substantially constantly dispersed by the turning bar rotating at a speed less than the moving web, which creates drag to prevent dust accumulation and build-up on any single point of the turning bar and the web. Drag also controls sheet handling since the web will “walk out” of the machine if the turning bar is permitted to free-wheelingly rotate. If desired, the turning bar can be configured to rotate in a direction opposite the moving web to further prevent dust accumulation on the turning. 
     In a further aspect of the invention, a turning bar assembly for use in manufacturing a paper web is provided. The turning bar as generally described above is affixed to a holder and configured to redirect the web from moving in one direction to moving in another direction as the web passes across the turning bar. More specifically, in this embodiment, a tube-like sleeve is rotatably disposed about the turning bar and rotates about the turning bar at substantially less than the operational speed of the web. Stated alternatively, the turning bar is fixed in this aspect while the tubular sleeve, for instance, rotates around the fixed turning bar and a plurality of bearings is disposed about the turning bar. The plurality of bearings in this aspect could be substituted with, for instance, plastic or bronze bushings, lubricant such as grease and the like and still permit the sleeve to rotate about the fixed turning bar. 
     According to another aspect of the invention, a method for precluding dust accumulation on a turning bar in a web manufacturing system is disclosed, which includes the steps of providing a turning bar rotatably disposed against a moving web of material; redirecting the moving web by the turning bar from a first incoming direction to a second outgoing direction; dispersing a dust originating from the moving web away from the turning bar by rotating the turning bar; and controlling the rotation of the turning bar between about 1% a speed of the moving web to some rotation speed less than the speed of the web. 
    
    
     Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the attached drawings in conjunction with the following detailed description of the drawings which exemplifies the best mode of carrying out the invention as presently perceived, or can be learned through practice of the invention. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other aspects and advantages of the present invention are apparent from the detailed description below and in combination with the drawings, in which: 
     FIG. 1 is a partial perspective view of a web forming device particularly showing a turning bar assembly and a partial section of a web material moving adjacent a turning bar according to the present invention; 
     FIG. 2 is a top perspective view of the embodiment as in FIG. 1; 
     FIG. 3 is a view of the arrangement as in FIG. 1 or  2  taken in the direction of line  111 — 111  in FIG. 2; 
     FIG. 4 is a cross-sectional view taken along lines IV—IV in FIG. 1 particularly showing a bearing arrangement in accordance with the invention; and 
     FIG. 5 is a cross-sectional view of an alternative bearing arrangement. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Detailed reference will now be made to the drawings in which examples embodying the present invention are shown. Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention. 
     The drawings and the following detailed description provide a full and detailed written description of the invention and the manner and process of making and using it, so as to enable one skilled in the pertinent art to make and use it. The drawings and detailed description also provide the best mode of carrying out the invention. However, the examples set forth herein are provided by way of explanation of the invention and are not meant as limitations of the invention. The present invention thus includes modifications and variations of the following examples as come within the scope of the appended claims and their equivalents. 
     As broadly embodied in the Figures, a turning bar assembly  10  is rotatably disposed adjacent a web of material W moving at an operational speed in a web forming device (shown in part in FIGS.  1 - 3 ). The turning bar assembly  10  includes a roller or turning bar  12 , which may be circular in cross-section but can have other shapes such as conical, concave, convex or the like. The turning bar  12  has a first end  14  and a second end  16  and is configured to receive, turn and transfer the web W downstream or across stream in the web forming device. More specifically, a first mounting end or mount  18  is attached to the first end  14  of the turning bar  12 . A second mounting end or mount  22  is attached to the second end  16 . In this arrangement, the turning bar  12  is configured to rotate 360 degrees relative to the first and second mounts  18 ,  22  at less than the operational speed of the moving web W. 
     Generally, the turning bar  12  is controllably, rotationally driven by drive apparatus  28 , as shown in FIG. 2, which may include a drive belt or o-ring  32 , a drive rod or shaft  30  and motor M as will be further described below. It should be noted that the turning bar  12  can be driven by mechanisms other than as shown in the drawings, such as by a drive unit directly electromotively coupled to the turning bar  12 . By way of example, a direct drive block and motor could be rotatably attached to the first mount  18  to linearly drive the turning bar  12  in lieu of the offset shaft  30 /belt  32  combination. Accordingly, various drive arrangements are contemplated for rotating the inventive turning bar  12  without departing from the purpose and scope of the invention. 
     In one aspect of the invention, the turning bar  12  is disposed at an angle other than 90° to the moving web W moving in a first direction A such that the turning bar  12  turns the moving web W in a second direction B as seen, for example, in FIGS. 1 and 2. The turning bar  12  in this aspect is rotatably configured to frictionally contact the moving web W at relatively different speeds such that dust from the moving web W does not accumulate on the rotating turning bar  12 . Stated another way, a nominal frictional force is created between a surface of the web W and the surface of the rotating turning bar  12  due to their relative speed differences, detailed below. This friction tends to remove dust from the turning bar  12  while assuring directional control of the moving web W. More specifically, the controlled speed ratio of the rotating turning bar  12  to the moving web W ensures that the dust is substantially constantly dispersed to prevent dust accumulation and build-up on the turning bar  12  and the web W. 
     By way of example, the drive belt  32  is disposed about a portion of the turning bar  12 . The shaft  30  and drive belt  32  cooperate to rotate the turning bar  12  when the drive apparatus  28  rotates the shaft  30  by the motor M. It is to be noted that although the shaft  30  is shown offset and above the turning bar  12 , other relative arrangements and geometries are possible to rotate the turning bar  12 . Further, the drive apparatus  28  could include a computer or other control device to program motor M, for instance, if automatic speed governoring or system start/stop is desired. Also if desired, the turning bar  12  in this aspect of the invention may be rotated in a direction opposite the moving web W to further reduce dust accumulation on the turning bar  12  such as by the creation of additional drag between the bar  12  and web W. 
     With more particular reference to FIGS. 1-4, the shaft  26  is shown disposed longitudinally within the turning bar  12  and affixed to the first and second mounting ends  18 ,  22 . The turning bar  12  is rotatably disposed about the shaft  26 . Although the shaft  26  described herein is a unitary shaft extending substantially the length of the turning bar  12 , it is contemplated that the shaft  26  could be formed in multiple pieces. For instance, those portions of the shaft  26  attached to the first end  14  and second end  16  of turning bar  12  could be severed and apart from each other such that the separate shaft portions extend into the turning bar  12  a sufficient distance to support a bearing assembly  33 , including bearings  34 , bushings  38  and spring pins  40 , as will be described below. 
     As shown in FIG. 3, the first mounting end  18  in this aspect is angled and removably attached to a first point or holding channel  20 . The second mounting end  22  is removably attached to a second point or mounting bracket  24 . A variety of other holders or holding elements other than channel  20  and bracket  24  can be provided. However, the inventors have found that the angled mounting end  18  and holding channel  20  facilitate maintenance and/or replacement of the turning bar assembly  10 . Further, the angled mounting tip  18  serves to facilitate longitudinal adjustments to turning bar  12 . Moreover, the turning bar  12  can be rotated such that if the turning bar  12  is held in place or is non-rotatable, the bar  12  can be revolved to increase longevity of the bar  12 . Eventually, the turning bar  12  can be repaired/replaced without replacement of the entire turning bar assembly  10 , such as mounts  20  and  24 . 
     FIG. 4 particularly illustrates a plurality of bearings  34  rotatably disposed within the turning bar  12  and about the shaft  26 . The bearings  34  cooperate to rotate the turning bar  12  at less than an operational speed of the web W in the web forming device. More specifically, in this aspect of the invention, the turning bar  12  and the plurality of bearings  34  are rotated by the drive apparatus  28  between 1% to about 20% of the operational speed. The bearings may be standard ball-type bearings or other standard antifriction bearings such as tapered rollers, needle rollers, or the like. 
     Optionally, the turning bar  12  may define a plurality of holes (not shown), which are configured to direct a pressurized gas via the turning bar  12  into contact with the moving web W. Use of a pressurized gas such as from a Co and a nozzle is known in the art and can be used for supplemental dust removal from the rotating turning bar  12  of the present invention if desired. 
     The first end  14  of the turning bar  12  may be disposed apart from the second end  16  between ten to about forty inches. An outer diameter D of the turning bar may be between ¼ inch to about eight inches. It should be noted that although these turning bar  12  dimensions accommodate the standard web material, a variety of other shapes and sizes for the turning bar  12  are contemplated by the invention. 
     With further reference to FIGS. 1-4, at least one bearing assembly  33  is disposed concentrically about the shaft  26  within the turning bar  12 . The bearing assembly  33  permits the turning bar  12  to rotate about the shaft  26  as previously described and includes the bearings  34  as described, bushings  38 , and spring pins  40 . 
     The bushings  38  are affixed to adapt the first and second ends  14 ,  16  to the shaft  26 . The bushings  38  may be selected from bronze bushings, phenolic bushings, steel, aluminum, brass, plastic and the like, depending on particular system requirements or specifications. The spring pins  40  hold the assembly  33  together as known and need not be further described to practice the invention. As seen in FIG. 3, a thrust washer  39  may be disposed between first mounting end  18 , for instance, and bar  12  as a spacer to prevent braking of the bar. Likewise, a thrust washer  39  can be inserted between the opposite end of bearing  34  and the second mounting end  22 . Such thrust washers provide clearance between the bearing  34  and other elements to prevent unnecessary friction or braking while the turning bar  12  is rotating. 
     In another aspect of the invention, as seen in pertinent part in FIG. 5, a turning bar assembly  10  for use in manufacturing a paper web W similar to the foregoing embodiments is provided. A turning bar  112  is affixed to a holder similar to bracket  24  and/or channel  20  in which the previously described turning bar  12  is mounted. A sleeve  36  is rotatably disposed about the turning bar  112 . In this aspect, the first mounting end  18  and a second mounting end  22  are fixed to the turning bar  112  such that the first mounting end  18  and the second mounting end  22  are removably affixed to the bracket  24 . In contrast to the embodiment shown in FIG. 4, a plurality of bearings  134  is disposed about the turning bar  112  and the sleeve  36  is rotatably disposed about the plurality of bearings  134 . Thus, the sleeve  36  is rotated about the turning bar  112  at substantially an operational speed of the web W by the drive apparatus  28 . 
     With further reference to the drive apparatus  28 , the motor M along with a controller such as a computer can be configured to rotate the turning bar  12  or sleeve  36  at variable speeds depending on system requirements. For instance, a speed between {fraction (1/100)} to ½ of the operational speed as described above may be programmed into the controller or directly into a programmable motor M. By way of example, the motor M can be programmed to alternately or selectively drive the turning bar  12  for a predetermined period of time at ⅕ of the operational speed followed by {fraction (1/100)} of the operational speed for a time and subsequently stop or freewheel the turning bar  12  until returning it to ⅕ of the operational speed for another period of time. Obviously, a number of programmable turning bar  12  speeds are contemplated by the present invention. 
     A method for precluding dust accumulation on a turning bar  12  in a web manufacturing system is disclosed in one aspect of the invention as seen in FIGS. 1-3. The method includes the steps of providing the turning bar  12  rotatably disposed against a moving web W of material; redirecting the moving web W by the turning bar  12  from a first incoming direction A to a second outgoing direction B; dispersing a dust that originates, for example, from the moving web W away from the turning bar  12  by rotating the turning bar  12 ; and controlling the rotation of the turning bar  12  from between {fraction (1/100)} a speed of the moving web W to about substantially the speed of the web W. The method may include the substep of selectively rotating the turning bar  12  in a direction opposing the movement of the web W. 
     While exemplary embodiments of the invention have been shown and described, those skilled in the art will recognize that other changes and modifications may be made to the foregoing examples without departing from the scope and spirit of the invention. For instance, specific shapes of various elements as shown in the drawings may be altered to suit particular applications. It is intended to claim all such changes and modifications as fall within the scope of the appended claims and their equivalents.