Device and method for installing or replacing a blade holder assembly

Abstract

The present invention provides a device and method for installing or replacing a blade holder assembly in web forming and handling machines, such as those used in paper, board, tissue, printing, and metal sheet applications. The invention addresses the limitations of existing blade holder assemblies, particularly in high-temperature environments where traditional loading / unloading elements fail prematurely. This novel blade holder assembly integrates high-temperature-resistant elements, significantly extending operational life by 5 to 10 times compared to conventional designs. The assembly is designed for ease of installation, allowing replacement without extensive machine disassembly, thereby reducing downtime and associated costs. The invention also offers enhanced structural integrity and reliability, making it a robust solution for environments where high thermal resistance and quick maintenance are critical. This approach ensures improved performance, longevity, and cost-efficiency in maintaining blade holder assemblies within industrial machinery.

Description

Device and method for installing or replacing a blade holder assemblyCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] There are no cross-related applications.FIELD OF THE INVENTION

[0002] The present invention generally relates to a device and a method for using a blade holder assembly used in web forming machines, such as in paper, board, and tissue machines, and in web handling machines, such as in printing and metal sheet machines. More specifically it relates to a device and a method for installing or replacing a blade holder assembly.BACKGROUND OF THE INVENTION

[0003] In some of existing equipment, the original manufacturer does not sell replacement parts anymore for their own blade holder models. The manufacturer recommends buying its new holder model to completely replace the existing blade holder. In most cases, this means that the final users (equipment owners) must remove a lot of parts (fabrics, rolls, walkways, etc.) in their machine to be able to install the new blade holder. This operation is very time consuming and extremely expensive for only installing one blade holder. Most end users (owners) have more than one such piece of equipment in their machines.

[0004] In addition, the loading / unloading element of the blade holder does not last very long when the temperature is above a specific temperature (on average 80° Celsius). Several doctoring applications with blade holder have an ambient temperature between 100° and 120° Celsius. In those applications, the loading / unloading element needs to be replaced every 6 months to avoid some failure and damage. The loading / unloading element is very expensive and unique. The loading / unloading element fails regularly before the hose replacement date and generates big production loss to the final users.SUMMARY OF THE INVENTION

[0005] The equipment according to the invention is used particularly in web forming machines, such as in paper, board, and tissue machines, and in web handling machines, such as in printing and metal sheet machines.

[0006] The invention is intended to offer a device and method to provide a lower cost alternative for the replacement of a blade holder assembly with economic loading / unloading elements (2 air tubes) with high temperature resistance, which will last a much longer (between 5 & 10 times according to the hose selection) than the one of many existing equipments. This device and method will not require removing much equipment from the machine of the final users compared to the installation of a completely new blade holder on the existing doctor structure.

[0007] The advantages of the invention are that it provides an economical alternative, a quick and easy replacement, no field notes are required, and a significant increase in reliability and sustainability on loading / unloading elements.

[0008] An object of the present invention is to provide an apparatus and method of conversion to a doctor blade holder assembly to make it more durable at high ambient temperature, quicker and easier installation, and more economical to replace than other apparatus and method options.

[0009] Other and further aspects and advantages of the present invention will be obvious upon an understanding of the illustrative embodiments about to be described or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other aspects, features and advantages of the invention will become more readily apparent from the following description, reference being made to the accompanying drawings in which:

[0011] Figure 1 is a cross-sectional view of a blade holder assembly comprising a composite finger according to an embodiment of the present invention.

[0012] Figure 2 is a cross-sectional view of a blade holder assembly comprising a stainless- steel finger according to an embodiment of the present invention.

[0013] Figure 3 is a side perspective view of the blade holder assembly shown in Figure 1.

[0014] Figure 4 is a side perspective view of the blade holder assembly shown in Figure 2.

[0015] Figure 5 is an exploded view of the blade holder assembly shown in Figure 3.

[0016] Figure 6 is an exploded view of the blade holder assembly shown in Figure 4.

[0017] Figure 7 is a rear view of a blade holder assembly set in a doctor structure according to an embodiment of the present invention.

[0018] Figure 8 is a side view of a blade holder assembly comprising a stainless-steel finger according to an embodiment of the present invention.

[0019] Figure 9 is a side perspective view of the blade holder assembly shown in Figure 8.DETAILED DESCRIPTION OF THE INVENTION

[0020] A novel blade holder assembly will be described hereinafter. Although the invention is described in terms of specific illustrative embodiments, it is to be understood that the embodiments described herein are by way of example only and that the scope of the invention is not intended to be limited thereby.

[0021] Referring to FIGS. 1, 3, and 5 there is shown a blade holder assembly or blade holder conversion kit 100 with a blade or doctor blade 104 which blade holder assembly 100 includes composite finger.

[0022] FIGS. 2, 4, and 6 show a blade holder assembly or blade holder conversion kit 100 with a blade or doctor blade 104 which blade holder assembly 100 includes several stainless- steel fingers.

[0023] The blade holder assembly also comprises a holder 108, a front hose or unloading tube 112, a retaining rod 116, a rear hose or loading tube 120, a top plate 124, and a backing blade 128 only used with composite finger version. The blade 104 is inserted in the holder 108.

[0024] The composite finger version of holder 108 has a cavity or mid cavity 132 that is set on existing mounting base 136. The existing mounting base 136 has a front rod-like part 140 that slides inside the mid cavity 132. The shape of the front part 140 allows the rotational movement of the blade holder assembly 100 around the front part 140 of the existing mounting base 136 which acts as a fulcrum for the holder 108. The stainless-steel finger version of holderl08 has a cavity or mid cavity 132 that is set on a slotted tube or liner 142 glided on existing mounting base 136. The stainless-steel finger version assembly sits on top of the liner142 and is attached using 2 cutter pins 145, 146 at one end. The slotted tube or liner 142 has a cylindrical shape that is mounted directly on the existing mounting base, has a front rod-like part 140 that slides inside the mid cavity 132. The liner 142 is used only with the stainless- steel finger version to prevent any wear on the existing mounting base 136. The liner 142 is held in place on the existing mounting base 136 by its shape and a cutter pin 146 at one end. The shape of the front part 140 and liner 142 allows the rotational movement of the blade holder assembly 100 around the front part of the existing mounting base 136 which acts as a fulcrum for the holder 108.

[0025] In some embodiments, some doctor structures have a blade holder assembly 100 with an existing mounting base 136 bolted to it. The blade holder assembly 100 conversion can be accomplished by the replacement of some parts of the existing doctor holder apparatus for a web forming machine to doctor a moving surface, which doctor apparatus includes a blade 104 and a blade holder 108, which all the blade holder parts will be replaced with the new holder conversion kit 100 except the existing mounting base 136.

[0026] In the blade holder assembly 100, loading and unloading elements 112 and 120 have been arranged between an existing mounting base 136 (bottom part) and blade holder holder 108 (top part) to load / unload the blade holder assembly 100 and further the blade 104.

[0027] The existing mounting base 136 forms one attachment counter-piece (male shape) of the pair of attachment counter-pieces which is intended to be attached to the doctor structure. The holder 108 forms the second attachment counter-piece (female shape) of the pair of attachment counter-pieces and is the assembled holder 108 of the blade holder assembly 100. Correspondingly, the holder 108 is arranged to cover the first attachment counter-piece or existing mounting base 136 from essentially the opposite sides. The holder 108 then forms a female round shape or mid cavity 132 that will fit on the first attachment counter-piece or existing mounting base 136 that forms a male round shape.

[0028] In FIG.l, the attachment screws 138 are shown by broken lines on the existing mounting base 136. In practice, it is preferable to do the assembly of all the fingers 108 with the top plate 124 during manufacture of the holder 100, so that the construction of the blade holder assembly 100 will be and remain unified when it will be installed on the existing doctorstructure at a mill site. The top plate 124 and the backing blade 128 are either made of composite material or stainless steel.

[0029] The blade holder assembly 100 is preferably formed from composite and / or stainless- steel parts. The composite holder 108 is preferably several individual fingers made with specific shape manufactured by machining, molding, 3D printing, and / or extruding methods. The stainless-steel holder 108 is preferably several fingers made with specific shape manufactured by machining and / or molding. In some embodiments, the backing blade 128 and the top plate 124 are made of carbon fiber. Thus, the backing blade 128, and with the blade 104, will conform well to the profile of the moving surface 144. The blade holder assembly 100 is preferably used for the cleaning of the surfaces of rotating rolls of a paper, board, or tissue machine. In these applications, the operating conditions favor the use of a high temperature resistant material with very low water absorption and stable dimensional tolerances.

[0030] Thus, the blade holder assembly 100 is advantageously easy to install and to replace. The blade 104 is then inserted to the holder 108 of the blade holder assembly 100.

[0031] The top plate 124 is fastened to the top surface of the holder 108 via screws 148 for both finger material and additional nuts 150 for the composite fingers. The top plate 124 has holes 152 on its surface. The holder 108 has holes 156 which align with the holes of the reinforcement plate 148 when the top plate 124 is placed over the top surface of the holder 108. This way, the top plate 124 is fastened to the holder 108 by means of screws 148 that pass through the holes 152 and 156 of the structure of both parts 108 and 124. The screws 148 are further secured in place by bolts or nuts 150. In some embodiments, the top plate 124 is fastened to the holder 108 using other fastening means such as rivets.

[0032] The several individual holder fingers are held together by means of a top plate 124 preferably made of stainless steel. The top plate 124 has holes 152 for fastening it on the holder 108. The size of the holes 152 and 156 is big enough to enable the thermal expansion of the holder 108 of the blade holder assembly 100 without the curling of the top plate 124. This is a requirement for the blade holder assembly 100 for remaining in the correct position.

[0033] A separate backing blade 128 fit to the blade holder 108 and relies against the blade 104, which one edge is inserted into the blade holder 108, the other edge extending closer tothe blade bevelled edge. Metallic, composite, and plastic blades 104 are generally used in accordance with the application. Usually, the blade 104 is used to doctor the moving surface 144 or to smooth a substance spread on the moving surface. The blade holder assembly 100 according to the invention is shaped so that different kinds of blade 104 can be fitted into the holder 108 of the new blade holder assembly 100. FIG. l shows a composite blade 104 in the blade holder assembly 100.

[0034] The holder 108 has a cavity or front cavity 164 located in front of the other cavity 132. The front cavity 164 hosts a front portion 168 of the front hose 112. The position of the front portion 168 of the front hose 112 is secured in the front cavity 164 via a retaining rod 116. The retaining rod 116 is inserted in the front portion 168 of the front hose 112.

[0035] The front cavity 164 has a partially cylindrical shape with lateral openings and a longitudinal rear opening or slot 170. The dimension of the slot 170 is narrower than the diameter of front cylindrical shaped portion of the front cavity 164. The dimension of the slot 170 is narrower than the retaining rod 116 thus creating a hinge which secures the position of the retaining rod 116 inside the front cavity 164. As a result, the position of the front part 168 of the front hose 112 is secured in the front cavity 164. The unloading tube or front hose 112 is inserted into a front cavity 164 (female shape) in the holder 108 and held in place by means of a retaining rod 116 inserted into the front hose 112 and therefore the finger as well.

[0036] The rear part 172 of the front hose 112 extends from the cavity 164 until it reaches the front part of the existing mounting base 136. A cylindrical rod 158 preferably goes through the stainless-steel holder 108 in order to increase the contact area between the unloading tube 112 and the holder 108. When the front hose 112 is inflated, the rear part 172 of the front hose 112 applies a pressure on the existing mounting base 136. This triggers the rotational movement of the blade holder assembly 100 backwards. As a result, the blade 104 is lifted from the moving surface 144. The loading tube or rear hose 120 is positioned under the mobile part which is the fingers of the blade holder assembly 100 and above the static part which is the existing mounting base 136 bolted on the doctor structure.

[0037] The rear hose 120 is located in a rear cavity 176 that is on the bottom face of the rear part of the holder 108. When inflated, the rear hose 120 triggers a frontward movement of theblade holder assembly 100 by applying pushing away the bottom surface of the rear cavity 176 from the existing mounting base 136.

[0038] According to the invention, the blade holder conversion kit 100 is also detachable fitted to the existing mounting base 136. Thus, the blade holder assembly 100 can move in the longitudinal direction of the blade 104, i.e., in the cross-machine direction. In practice, in a paper machine for example, the blade holder assembly 100 can be fitted by simply pushing it in from the side at one end and correspondingly removed by pulling it out.

[0039] The shape locking holds the fingers 108 on the mounting base 136 in the lateral direction of the blade 104. Thus, the blade holder assembly 100 is certain to remain in place in the machine direction. During operation, a lock attachment may be used to prevent crossmachine movement.

[0040] In the case of this blade holder assembly 100, the complete doctor structure and the mounting base 136 remain stationary while the blade holder assembly can pivot. Figures 1 and 2 show the blade holder assembly 100 on the loading mode.

[0041] The blade 104 fitted in the holder 108 is loaded against the moving surface 144 when the loading tube or rear hose 120 that is located on top of the existing mounting base 136 is inflated with air. Correspondingly, the return force is created by inflating the unloading tube or front hose 112 with air. As one tube inflates the other deflates as directed by a control panel (not shown).

[0042] The blade holder assembly 100 also allows the holder 108 to be easily cleaned and repaired outside the machine, as the entire blade holder assembly can be simply removed from the machine. In addition, during an incident, the parts of the blade holder assembly 100 most likely to deform or break are the blade 104 and backing blade 128 which are easiest, fastest, and most economical to replace.

[0043] In some embodiments, the moving surface 144 is a roll of a paper machine, of which only a small portion is shown. Generally, the blade holder assembly 100 is intended to treat a moving surface 144. In the doctor example, doctoring is used to remove impurities from the surface, or, for example in some positions in a paper machine, to remove the web itself. Inpaper, board, and other webforming machines, the moving surfaces 144 are also the surfaces of various cylinders and fabrics.

[0044] In some embodiments, the blade holder assembly 100 can also be used, for example, in web coating, in which a coating paste is applied to the surface of the moving web.

[0045] Shown on FIG 7, further, the equipment 400 consists of an assembly of different components or blade holder assembly 404, which is arranged in the vicinity of the moving surface 408 being treated. The blade holder assembly 404 includes a structure or frame 412, which is supported by two journals 416 mounted in bearings 420 bolted on a set of supports 424 on the sides of the machine frame. In practice, the structure 412 is locked in the correct position, for example, using a set of turnbuckle screws 428 or air cylinders. On the other hand, the set of turnbuckle screws 428 can be used to rotate the beam away from the moving surface 408 to set the doctor properly.

[0046] The blade holder assembly 404 also includes a finger 432, which is attached to an existing mounting base 436 (136 in FIG.l) located on the structure 412. The actual treatment member is a blade 440 fitted to the finger 432, the dimensions and material of which can vary in different applications. The blade 440 includes a doctoring bevelled edge 444, which is arranged to be brought into contact with the moving surface 408 by moving the finger 432. The moving surface 408 is then treated via the contact of the blade 440 on the moving surface.

[0047] In present equipment, the blade holder assembly 404, made of assembled pieces formed from composite materials having an existing mounting base 136 connected to the structure 412.

[0048] While illustrative and presently preferred embodiments of the invention have been described in detail hereinabove, it is to be understood that the inventive concepts may be otherwise variously embodied and employed and that the appended claims are intended to be construed to include such variations except insofar as limited by the prior art.

Claims

CLAIMS1) A doctor apparatus, for a web forming machine to doctor a moving surface, comprising: a doctor blade; a blade holder, itself comprising: a holder component to which a doctor blade and top plate are mounted; a frame mounting base to which the holder component is pivotally mounted; two elements located between the frame mounting base and the holder component to unload / load the blade holder and doctor blade.2) The doctor apparatus of claim 1 wherein the holder component includes several assembled fingers made from composite material.3) The doctor apparatus of claim 2 wherein the holder reinforcement plate is made of carbon fiber or stainless-steel bolted on the assembled fingers.4) The doctor apparatus of claim 3 wherein the holder top plate is made of carbon fiber or stainless-steel fitted to the assembled fingers.5) The doctor apparatus of claim 4 wherein the holder component has high temperature resistance loading / unloading elements.6) The doctor apparatus of claim 5 wherein the holder component has an unloading element inserted into a groove in the assembled fingers and held in place by means of a rigid element matching the groove shape when inserted into the unloading element.7) The doctor apparatus of claim 6 wherein the holder component slides easily on the existing frame mounting base.8) The doctor apparatus of claim 7 wherein the holder component has a portion forming one of a female hinge piece that will fit on the male hinge piece of the existing frame mounting base.9) An unloading element comprising an inflatable tube adapted to inserted into a groove in the assembled fingers of a doctor apparatus as claimed in claim 2 and a rigid element adapted to be inserted into the tube to hold the tube in place within the groove.10) An unloading element as claimed in claim 9 wherein the tube is made of rubber or a rubber like material.11) An unloading element as claimed in claim 9 wherein the rigid element is a rod.12) An unloading element as claimed in claim 11 wherein the rigid element is made of one of a group comprising steel, fiberglass, and carbon fiber.13) The doctor apparatus of claim 7, further comprising a liner adapted to be placed over the existing mounting base, the liner being designed to prevent wear on the existing mounting base and to allow the stainless-steel finger assembly to slide and rotate on the existing mounting base.14) The doctor apparatus of claim 13, wherein a cylindrical rod is inserted into the stainless-steel finger assembly, the cylindrical rod being positioned to increase the contact area between the unloading tube and the stainless-steel finger assembly, thereby enhancing the stability and efficiency of the unloading process.15) The doctor apparatus of claim 14, further comprising a set of lock clamps adapted to secure the stainless-steel finger assembly on top of the liner, the lock clamps being configured to prevent undesired movement of the stainless-steel finger assembly during operation, ensuring proper alignment and functionality.

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