Description:FIELD OF INVENTION
[001] The present invention relates to an apparatus and a method to facilitate tube cutting using a chopsaw assembly. Also the invention relates to the manufacturing of superheater, reheater, and economizer components in the thermal steam generators. More particularly, the invention relates to cutting tubes easily and cost effectively to enable the production of boilers.

BACKGROUND OF THE INVENTION

[002] Existing cutting tools such miter saw, band saw has unfortunately a heavy structure and is moreover cumbersome to operate, especially because the operator needs to tilt the saw blade for being able to cut a rod or tube like structure. In the tilted position of the saw blade is the operator forced to advance the saw blade through the workpiece by means of a hand being in an awkward position.

[003] Further the coils are pressure part components in thermal boilers that carry high pressure steam to turbines. The coils are a set of hollow tubes kept in a pre-designed sequence such as circuits with necessary attachments. The coils are assembled as a unit inside the boiler of a thermal power plant. Circuits are of different lengths. Various attachments are used for the coil depending on the design. Standard tubes are of fixed length but coil circuits require different lengths. The defective joints are cut from the circuit by cutting the tube, usually using bandsaw machine. Such cuts made by bandsaw machine are to be made in specific areas to take out the defective weldment. Due to hardness of the weldment and the parent material, a bandsaw blade could cut only 3 to 4 joints.

[004] Also, in the manufacturing of high pressure steam generator coils, panels are made in parts which are then assembled at site during erection. Normally 660 MW boiler consists of 605 coils approximately, depending on the design. In one such coil, 400 to 500 meters of tubes are required and 100 to 150 joints are welded using Tungsten Inert Gas (TIG) to join the coils. So every boiler consists of minimum 60000 welded tube joints. For TIG joints, two ends of the tubes are chamfered and bored for perfect matching. The defective joint has to be taken out by cuttings around the joint at two places using bandsaw machine. After that, chamfering boring process is done prior to welding. The defective joints are cut from the circuit by cutting the tube, usually using bandsaw machine. These have only 0.6mm thickness blade. Due to high load demand, this technique requires more time, more bandsaw blades to be consumed and also damages the machine frequently.

[005] Due to hardness of the weldment and the parent material, a bandsaw blade can cut only few joints. Frequent issues are faced in bandsaw machine while cutting the weldment. This process involves more blade cost due to replacement, material wastage and more manpower usage. If a single tube has more than two defective joints in a single length, it results in shortage of required length. It then requires a tube extension to be made which takes more hectic work and consumes extra manpower

[006] No prior art found for chopsaw cutting machine to facilitate tube cutting in boiler pressure part coils. However, few prior arts showing typical chop saw which are listed below.

[007] EP2985119A1 titled “A chop saw” discuss about a chop saw which comprises a base having a work surface. A motor unit pivotally mounted on the base. An electric motor mounted within the motor unit. A handle connected to the work motor unit; an ON/OFF switch to activate the motor when provided with an electrical power supply; a fence mounted on the base which traverses the work surface. An adjustable clamp capable of co-operating with the fence to secure a work piece to be cut on the work surface characterized in that that there is provided an overload switch which automatically cuts off the electrical current to the motor when the motor draws an electrical current which is greater than a predetermined amount.

[008] US5720096A titled “Power tool with locking fence” describes about a locking fence for a power tool such as a chop saw, or for a work surface of a workbench, is capable of being moved to a selected location on the chop saw base or work surface and oriented at a selected angular orientation relative to the chop saw blade. The fence is locked simultaneously in such location and orientation when an operator rotates a cam actuator to lift a first clamping member away from the fence, which in turn draws a second clamping member into clamping engagement with the underside of a workpiece support of the base, and which further forces a cam portion of the actuator against the fence. No tools are required to lock or unlock the fence. The fence defines an arcuate slot for enabling the angular orientation to be adjusted. The arcuate slot is maintained in juxtaposition to a slot formed in the work surface for enabling movement of the fence to its selected location on the workpiece support or work surface, by linking screws linking the slots.

[009] None of the above cited prior art discusses the issues related to an apparatus or any fixture to facilitate tube cutting of coils using chopsaw machines.

[0010] The present invention is directed to a simple apparatus which facilitates the tube cutting for pressure part components in thermal boilers application

OBJECTS OF THE INVENTION

[0011] It is therefore a principal object of the present invention is to develop an apparatus and method to facilitate tube cutting in boiler pressure part coils using a chop saw assembly.

[0012] Another object of the present invention is to develop the apparatus using the chop saw assembly in a robust manner.

[0013] Another object of the present invention is to design the apparatus using the chop saw assembly to produce a higher throughput and could cut the weldment in a single cut.

[0014] Another object of the present invention to design the apparatus as simple, lightweight and more efficient.

[0015] Another object of the present invention is that apparatus using chop saw assembly is sturdy for cutting the tubes

[0016] These and other objects and advantages of the present subject matter will be apparent to a person skilled in the art after consideration of the following detailed description taken into consideration with accompanying drawings in which preferred embodiments of the present subject matter are illustrated.

SUMMARY OF THE INVENTION

[0017] This summary is provided to introduce concepts related to an apparatus and a method to facilitate tube cutting using a chopsaw assembly.

[0018] The present invention relates to an apparatus facilitate tube cutting using a chopsaw assembly is fixed on a shaft which is disposed on a base frame having substantially “L” shaped angles formed into a rectangle frame and at least one side pillar for holding the shaft which are welded at a right angle position having a specific gap. An adjusting means is provided on the shaft for facilitating return movement. A top clamp plate along with a block is configured to hold an at least one tube and a chop saw blade centre is positioned concentric to the block which is having substantially “V” shape arrangement in the base frame. A hinge mechanism is provided in the top clamp plate and fixing a lock bolt and nut to hold the at least one tube in a proper position. The chop saw assembly head is positioned on the at least one tube at the area where cutting is required.

[0019] In a preferred embodiment a method of cutting a tube using a chop saw assembly, comprising the steps: fixing a chop saw assembly on a shaft which is disposed on a base frame having substantially “L” shaped angles formed into a rectangle frame and at least one side pillar for holding the shaft and welding at a right angle position having a specific gap. Facilitating return movement of the chop saw assembly by using an adjusting means which is provided on the shaft. Configuring a top clamp plate along with a block for holding an at least one tube and positioning a chop saw blade centre concentric to the block which is having substantially “V” shape arrangement in the base frame. Providing a hinge mechanism in the top clamp plate and fixing a lock bolt and nut for holding the at least one tube in a proper position. Positioning the chop saw assembly head on the at least one tube at the area where cutting is required and tightening the base frame and cutting the at least one tube for a required dimension by using the chop saw assembly.

[0020] In an aspect the apparatus is used in the manufacturing of super heater, reheater, economizer components in the thermal steam generators and production of boilers.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0021] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods or structure in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:

[0022] FIG. 1 is a perspective view of a base frame design in an embodiment of the present invention;

[0023] FIG. 2 is a top perspective view of a modified block having “V” shaped arrangement for holding a tube at bottom side for cutting in an embodiment of the present invention;

[0024] FIG. 3 is a perspective view of a top clamp plate for holding at top for cutting in an embodiment of the present invention;

[0025] FIG. 4 is a perspective view of a lock bolt and nut to hold the tube rigid in an embodiment of the present invention;

[0026] FIG. 5 is a perspective view of an apparatus comprising the modified frame for a chop saw assembly to cut tubes with position in an embodiment of the present invention;

[0027] FIG. 6 is a front view of the chop saw assembly with tube positioning in an embodiment of the present invention;

[0028] FIG. 7 is a side view of the chop saw assembly with tube holding position in an embodiment of the present invention;

[0029] FIG. 8 is a front view of the chop saw assembly without tube holding in an embodiment of the present invention; and

[0030] FIG. 9 shows a flow diagram of a method for the apparatus having chop saw assembly to cut a tube in an embodiment of the present invention.

[0031] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAIL DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

[0032] While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiment thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

[0033] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that a device, system, assembly that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device. In other words, one or more elements in a system or device proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or device.

[0034] The present invention relates to an apparatus (100) to facilitate tube cutting in boiler pressure part coils using chop saw assembly.

[0035] FIG. 1 is a perspective view of a base frame (2) design in an embodiment of the present invention. As shown in FIG.1 the base frame (2) is designed for holding the chop saw assembly (10) (as shown in FIG.6). The chop saw assembly (10) is fixed on a shaft (1) which is disposed on the base frame (2). In a preferred embodiment the chop saw assembly (10) comprises a chop saw head, chopsaw mounting hole. Also, the chop saw assembly (10) is a machine. In a preferred embodiment substantially ‘L’ angles are measured and converted into the base frame (2) which is rectangular in shape. The side pillars are prepared using plates. In a preferred embodiment the height of the chopsaw mounting hole is designed according the usage of a chop saw head. The rectangular frame (2) and pillars are welded perpendicular to each other and a specified gap is set for fixing the chop saw assembly (10). The shaft (1) is cylindrical in shape and a spring is used for assembling the chop saw head with the base frame (2). In a preferred embodiment an adjusting means is provided such as spring is provided on the shaft (1) for return movement. Further the adjusting means has a stopper provided in the spring-return. The adjusting means reverses the chop saw assembly (10) to the original position without any manual action.

[0036] FIG. 2 is a top perspective view of a modified block (3) which is having substantially “V” shape arrangement for holding a tube at bottom side for cutting in an embodiment of the present invention. In a preferred embodiment the block (3) which is having substantially “V” shape arrangement are made from a square block and configured for holding 38mm – 51mm diameter tubes. The block (3) which is having substantially “V” shape arrangement and a chopsaw blade are concentrically positioned. In a preferred embodiment the block (3) which is having substantially “V” shape arrangement are welded to the base frame (2).

[0037] FIG. 3 is a perspective view of a top clamp plate (4) for holding chop saw assembly (10) in an embodiment of the present invention. In one embodiment the top clamp plate (4) is configured such that along with the base frame (2) holds 38 mm – 51 mm diameter tube for top side clamping. A hinge mechanism is provided in the rectangle frame (2) for the top clamp plate (4) and a swivel bended plate welded in the hinge and covers the bottom of the block (3) which is having substantially “V” shape arrangement.

[0038] FIG. 4 is a perspective view of a lock bolt (5) and nut (6) to hold the tube rigidly in an embodiment of the present invention. In one embodiment the top clamp plate (4) which is locked by using hinge mechanism along with the lock bolt (5) and nut (6) type fastener.

[0039] FIG. 5 is a perspective view of an apparatus (100) comprising the modified frame for the chop saw assembly (10) to cut tubes with position in an embodiment of the present invention. As shown in FIG.5, the base frame (2) is modified in accordance with the chop saw assembly (10) to be used in the apparatus (100) for cutting with tube holding. In a preferred embodiment FIG.5 shows the complete position of tube cutting process.

[0040] FIG. 6 is a front view of the chop saw assembly (10) with tube positioning in an embodiment of the present invention. In a preferred embodiment the chop saw assembly (10) is fixed on the shaft (1) which disposed on the base frame (2). In a preferred embodiment the base frame (2) is a base plate. The block (3) which is having substantially “V” shape arrangement in the top is welded onto the top clamp plate (4). A chopsaw blade centre is exactly matched to be concentric to the block (3) which is having substantially “V” shape arrangement in the base frame (2). The base frame (2) is positioned in the required positioned by manual operating procedures. The top clamp plate (4) is bended and along with the block (3) which is having substantially “V” shape arrangement to hold different dimensions of at least one tube in a desired position. The top clamp plate (4) is provided with a hinge mechanism, fixed in the base frame (2) which is rectangular is shape. The top clamp plate (4) is locked by using hinge mechanism and lock bolt (5) and a nut (6) to hold the tube rigidly and in proper position. The chopsaw head is fixed to the shaft (1) and positioned on an each one of the at least one tube area where cutting is required. After tightening the base frame (2), the chop saw assembly (10) cut at least one tube in one stretch. In a preferred embodiment all the degrees of freedom of cutting is arrested such that cutting is repeated in a precision manner. After cutting, the chop saw assembly (10) is releases by unlocking the lock bolt (5) and the nut (6). In a preferred embodiment the apparatus (100) is held by operator hand and removed after the completion of cutting process.

[0041] FIG. 7 is a side view of the chop saw assembly (10) with tube holding position and FIG. 8 is a front view of chop saw assembly (10) without tube holding in an embodiment of the present invention. The apparatus (100) having the chop saw assembly (10) facilitates the tube cutting in pressure part coils. A connecting means adjust the height of the chopsaw mounting hole based on a chop saw head position. In a preferred embodiment the connecting means are manually operated fasteners. The height of the mounting shaft (1) is positioned in accordance with the chop saw head. In a preferred embodiment the adjusting means is a spring and a stopper. The apparatus (100) is configured to use a fixture which facilitates tube cutting. The apparatus (100) is configured for manufacturing of super heater, reheater, and economizer components in the thermal steam generators and production of boilers.

[0042] FIG. 9 shows a flow diagram of a method (200) for the apparatus (100) having chop saw assembly (10) to cut a tube in an embodiment of the present invention. The method (200) comprises a step (202) of fixing a chop saw assembly (10) on a shaft (1) which is disposed on a base frame (2) having substantially “L” shaped angles formed into a rectangle frame and at least one side pillar for holding the shaft (1) and welding at a right angle position having a specific gap. Furthermore, the method (200) comprises a step (204) facilitating return movement of the chop saw assembly (10) by using an adjusting means which is provided on the shaft (1). Furthermore, the method (200) comprises a step (206) configuring a top clamp (4) along with block (3) having substantially “V” shape arrangement for holding an at least one tube and positioning a chop saw blade centre concentric to the block (3) in the base frame (2). Furthermore, the method (200) comprises a step (208) of providing a hinge mechanism in the top clamp plate (4) and fixing a lock bolt (5) and nut (6) for holding the at least one tube in a proper position. Furthermore, the method (200) comprises a step (210) of positioning the chop saw assembly (10) head on the at least one tube at the area where cutting is required and tightening the base frame (2). Furthermore, the method (200) comprises a step (212) of cutting the at least one tube for a required dimension by using the chop saw assembly (10).

[0043] In one embodiment using the chop saw assembly (10) the plurality of tubes are welded together to attain the required length. Using the apparatus (100) the obtained joints are perfect and of same quality as the parent tube. Using the apparatus (100) boiler regulations for safety measures are compiled without deviating the welding joints. Using the apparatus (100) the defective joint in the circuit are removed easily.

[0044] In one embodiment the apparatus (100) is a more robust and the chop saw assembly (10) used for cutting a plurality of tubes in a sturdy manner. The apparatus (100) yields a higher throughput and cut the weldment in a single cut. In a preferred embodiment the apparatus (100) is designed to be used for a different application before the coil is formed. The apparatus (100) facilitate cutting of tubes in coils using the chop saw assembly (10). The apparatus (100) is simple, lightweight and more efficient than the traditionally employed bandsaw.

[0045] In one embodiment the apparatus (100) helps to reduce the cutting process and material wastage. Using the apparatus (100) the operator fatigue reduced drastically due to less effort requirement and the blade consumption is reduced. Additionally, frequent breakdowns of the bandsaw machine is avoided by using the apparatus (100)

[0046] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.

[0047] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope. The present invention will now be described more specifically with reference to the following specification.

[0048] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.

[0049] Although embodiments for the present subject matter have been described in language specific to package features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/device of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

[0050] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”

[0051] It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present invention contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and end products resulting from the practice of the methods herein. The use of “comprising” or “including” also contemplates embodiments that “consist essentially of” or “consist of” the recited feature.

[0052] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

Claims:We Claim
1. An apparatus (100) to facilitate tube cutting using a chopsaw assembly (10) comprising:
a shaft (1) which is disposed on a base frame (2) having substantially “L” shaped angles formed into a rectangle frame and at least one side pillar for holding the shaft (1) which are welded at a right angle position having a specific gap to fix the chop saw assembly (10);
an adjusting means is provided on the shaft (1) for facilitating return movement;
a top clamp plate (4) along with a block (3) is configured to hold an at least one tube and a chop saw blade centre is positioned concentric to the block (3) in the base frame (2), wherein the block (3) is having substantially “V” shape arrangement;
a hinge mechanism is provided in the top clamp plate (4) and fixing a lock bolt (5) and nut (6) to hold the at least one tube in a proper position; and
the chop saw assembly (10) head is positioned on the at least one tube at the area where cutting is required.

2. The apparatus (100) as claimed in claim 1, wherein the height of a chopsaw mounting hole is adjusted according to the positioning of the shaft (1).

3. The apparatus (100) as claimed in claim 1 to 2, wherein the lock bolt (5) and nut (6) are used as a manually operated fasteners to adjust the chopsaw mounting hole position.

4. The apparatus (100) as claimed in claim 1 to 3, wherein the height of the shaft (1) is positioned in accordance with the chop saw head.

5. The apparatus (100) as claimed in claim 1 to 4, configured for manufacturing of super heater, reheater, economizer components in the thermal steam generators and production of boilers.

6. The apparatus (100) as claimed in claim 1 to 5, configured to facilitate tube cutting in pressure part coils.

7. The apparatus (100) as claimed in claim 1, wherein the adjusting means is a spring and a stopper.

8. A method (200) for facilitating a tube cutting using a chop saw assembly, comprising the steps:
fixing a chop saw assembly (10) on a shaft (1) which is disposed on a base frame (2) having substantially “L” shaped angles formed into a rectangle frame and at least one side pillar for holding the shaft (1) and welding at a right angle position having a specific gap;
facilitating return movement of the chop saw assembly (10) by using an adjusting means which is provided on the shaft (1);
configuring a top clamp plate (4) along with a block (3) for holding an at least one tube and positioning a chop saw blade centre concentric to the block (3) in the base frame (2), wherein the block (3) is substantially having a “V” shape arrangement;
providing a hinge mechanism in the top clamp plate (4) and fixing a lock bolt (5) and nut (6) for holding the at least one tube in a proper position;
positioning the chop saw assembly (10) head on the at least one tube at the area where cutting is required and tightening the base frame (2), and
cutting the at least one tube for a required dimension by using the chop saw assembly (10).