Claims:WE CLAIM:
1. A replaceable assembly for surface milling at top and bottom end faces of turbine blade in horizontal milling machine for simultaneous height and angular adjustment, the replaceable assembly comprising:
a base block (100);
a lower holder block (200);
a rotating part (300) for angle adjustment;
an upper clamp (400) for rotating part;
an angle adjustment wedge (500); and
a lower wedge (600) for height adjustment provided with bolts (700),
wherein, height adjustment is actuated by rotation of the bolts (700) for height adjustment and thereby translating the lower wedge (600) for height adjustment, which in turn changes the height of the lower holder block (200) and the rotating part (300) for angle adjustment.
2. The replaceable assembly as claimed in claim 1, wherein angle adjustment is carried out by fastening angular wedges of the angle adjustment wedge (500) of different angle ranging from 1° to 5° as per blade rhomboid angle and thereby rotating the rotating part (300) for angle adjustment.
3. A process of simultaneous height and angle adjustment such that the replaceable assembly as claimed in Claim 1 is equivalent to the changeable pad at root and changeable pad at shroud, the process comprising:
- adjusting the calculated height in the replaceable assembly by rotating the bolt (700) for height adjustment;
- sliding the lower wedge (600) for height adjustment;
- moving lower holder block (200) and the rotating part (300) for angle adjustment together;
- adjusting the rhomboid angle of the blade by the inserting required angle adjustment wedge (500);
- fastening the angle adjustment wedge (500) with grub screw (800) for clamping; and
- fastening the replaceable assembly to the angle block with the help of standard bolts through counterbore holes in the base block (100).
, Description:A REPLACEABLE ASSEMBLY FOR SURFACE MILLING AND SIMULTANEOUS HEIGHT AND ANGULAR ADJUSTMENT OF TURBINE BLADE
FIELD OF INVENTION
[001] The present invention relates to steam turbine blade manufacturing technology. More particularly, the present invention relates to a compact, replaceable assembly for simultaneous height and angular adjustment of a resting surface used as lower support to hold turbine blades in a hydraulically clamped fixture for surface milling at top and bottom end faces of blade in horizontal milling machine.

BACKGROUND OF THE INVENTION
[002] As a general practice worldwide, steam turbine blades are manufactured in 5-axis machines from metal bar stocks that is blanks of different rectangular cross- sections & lengths. For radius milling operation at end faces of blades as mentioned hereinabove, the blade is clamped in fixture hydraulically in the fixture keeping its axis parallel. As different dimensions of blade change with different stages of blades, the dimensions and angle of root base pad and shroud base pad change.

[003] For this, different pads are manufactured for several different blades due to change in dimensions, causing some huge unique relations between blades and pads causing a huge volume of inventory as well as consumption of material, machine hours, tooling etc. to manufacture the pads. To standardize the pads and to introduce a single mechanism to adjust both angle and height was required to be designed which in turn reduces problem of huge volume of inventory as well as consumption of material, machine hours, tooling etc. to manufacture the pads.

[004] According to the present invention, the foregoing and other disadvantages, shortcomings, inefficiencies and problems are overcome by providing a compact, replaceable assembly for simultaneous height and angular adjustment of a resting surface used as lower support to hold turbine blades in a hydraulically clamped fixture for surface milling at top and bottom end faces of blade in horizontal milling machine.

OBJECTS OF THE INVENTION
[005] The present disclosure overcomes the above-mentioned problems, and an object of the present disclosure is to standardize the blade supporting pads and to introduce a single mechanism to concurrently adjust both angle and height which in turn largely eliminates the problem of huge volume of inventory as well as consumption of material, machine hours, tooling etc. to manufacture different pads.

[006] Another object of the present invention is to establish a technology that can enable to concurrently adjust both angle and height of the clamped blade during manufacturing, that too with great accuracy through a method and apparatus that is compact, foolproof and inherently free from tendency to error fall out of adjustment.

[007] Another object of the present invention is to cure the defects existing in the prior art as mentioned in part above, and to provide a means to replace multiple unique pads required for manufacturing of different turbine blades with single mechanism to standardize the pads having the smart ability to adjust both angle and height of the clamped blade during manufacturing.

[008] Another object of the present invention is to provide a solution to the issues in prior art provided that the proposed solution is having low initial cost and upkeep, great and continuing accuracy inherent in its design and operation, ruggedness and simplicity in its construction and operation, all to the ultimate end of faithfully and consistently reproducing accurately machined turbine blades.

SUMMARY OF THE INVENTION

[009] The present invention relates to a replaceable assembly for surface milling at top and bottom end faces of turbine blade in horizontal milling machine for simultaneous height and angular adjustment, the replaceable assembly includes a base block (100); a lower holder block (200); a rotating part (300) for angle adjustment; an upper clamp (400) for rotating part; an angle adjustment wedge (500); and a lower wedge (600) for height adjustment provided with bolts (700), wherein, height adjustment is actuated by rotation of the bolts (700) for height adjustment and thereby translating the lower wedge (600) for height adjustment, which in turn changes the height of the lower holder block (200) and the rotating part (300) for angle adjustment.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0010] Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings of the exemplary embodiments and wherein:
Figure 1 shows: a line representation of Base block in accordance to the present invention.
Figure 2 shows: a line representation of lower holder block in accordance to the present invention.
Figure 3 shows: a line representation of rotating part for angle adjustment in accordance to the present invention.
Figure 4 shows: a line representation of upper clamp for rotating part in accordance to the present invention.
Figure 5 shows: a line representation of angle adjustment wedge in accordance to the present invention.
Figure 6 shows: a line representation of lower wedge for height adjustment as per figure 6 in accordance to the present invention.
Figure 7 shows: a line representation of bolt for height adjustment, as shown in figure 6, in accordance to the present invention.
Figure 8 shows: a line representation of grub screw for clamping in accordance to the present invention.
Figure 9A-9B shows: a three (3) dimensional representation of the proposed invention for clamping in accordance to the present invention.
Figure 10 shows: a three (3) dimensional representation of blade clamped hydraulically in the proposed device and wherein blade centre axis is aligned in such a way that the blade axis remains horizontal to both the planes A and B as shown in accordance to the present invention.
Figure 11A-11B shows: a 3 three (3) dimensional representation of proposed assembly, equivalent to the changeable pad at root and changeable pad at shroud, clamping the blade during manufacturing on a horizontal milling machine in accordance to the present invention.
Figure 12-13 shows: a line representation showing variable dimensions H and angle A of a Standard turbine blades and other critical dimensions in accordance of present invention

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

[0011] The present invention, now be described more specifically with reference to the following specification.

[0012] 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 1-12.

[0013] In accordance with an embodiment of the present disclosure, reference is made to the following figures and associated components.

[0014] Figure 1 shows a line representation of Base block 100 in accordance to the present invention.

[0015] Figure 2 shows a line representation of lower holder block 200 in accordance to the present invention.

[0016] Figure 3 shows a line representation of rotating part 300 for angle adjustment in accordance to the present invention.

[0017] Figure 4 shows a line representation of an upper clamp 400 for rotating part in accordance to the present invention.
[0018] Figure 5 shows a line representation of angle adjustment wedge 500 in accordance to the present invention.

[0019] Figure 6 shows a line representation of lower wedge 600 for height adjustment as per figure 6 in accordance to the present invention.

[0020] Figure 7 shows a line representation of bolt 700 for height adjustment, as shown in figure 6, in accordance to the present invention.

[0021] Figure 8 shows a line representation of grub screw 800 for clamping in accordance to the present invention

[0022] The design of the present invention summarily consists of the following parts working in the assembly for height and angle adjustment of the resting surface for the blade. The assembly has the facility to adjust height of the resting surface for the blade as shown in figure 9a as well as angular adjustment can also be done as per requirement of the blade. The height adjustment is actuated by rotation of the bolt 700 for height adjustment as per figure 7 and thereby translating the lower wedge 600 for height adjustment as per figure 6, which in turn changes the height of the lower holder block 200 as per figure 2 and the rotating part 300 for angle adjustment as in figure 3. The angle adjustment is carried out by fastening angular wedges of the angle adjustment wedge 500 as per figure 5 of different angle ranging from 1° to 5° as per blade rhomboid angle (whole numbers) and thereby rotating the rotating part 300 for angle adjustment as in figure 3.

[0023] Twisted profile steam turbine blades are manufactured from alloy Steel rectangular bars in CNC 5-axis milling machines in one setup. The rectangular bars, raw material for the blades, are called blanks. As per design, the top and bottom surfaces of blades have certain radius as per the design of rotor and stator of the turbine. These end faces as shown in fig 11a and 11b are milled for the radius as per design in horizontal milling machines. The fixture arrangement is as shown in figures 11A and 11B. The main criteria for holding the blades in the fixture is ensuring.

[0024] The both top and bottom surfaces are easily accessible by tool for milling, i.e. face milling for roughing and slab milling for finishing. In an embodiment, the blade is clamped hydraulically in the fixture. Next, the blade center axis is aligned in such a way that the blade axis remains horizontal to both the planes A and B as shown in figure 10.

[0025] In figure 11a and 11b, root side of the blade is clamped with angle block and changeable pad at root at bottom of blade; root locator at back side of blade; top thrust piece and front thrust piece clamp hydraulically as shown.

[0026] Similarly, the shroud side is clamped with angle block and changeable pad at shroud at bottom of blade; shroud locator at back side of blade; top thrust piece and front thrust piece clamp hydraulically as shown.

[0027] To ensure blade center axis is aligned in such a way that the blade axis remains horizontal to both the planes A and B as shown in figure 10, with the change in pitch, rhomboid, thickness, rhomboid angle, taper angle, blade height and other dimensions, the angle and height of the changeable pads as mentioned in figure 11a and 11b at root side as well, as shroud side changes. For this, different pads with height and angles are manufactured for different blades. This causes a large inventory, material consumption and machine hour, tooling etc.

[0028] In the present invention, the assembly consists of the base block 100 as in figure 1, the lower holder block 200 as per figure 2, the rotating part 300 for angle adjustment as in figure 3, the upper clamp 400 for rotating part as per figure 4, the angle adjustment wedge 500 as per figure 5, the lower wedge 600 for height adjustment as per figure 6, the bolt 700 for height adjustment as per figure 7, and the grub screw 800 for clamping as per figure 8.

[0029] A process of simultaneous height and angle adjustment so that the entire assembly as described above is equivalent to the changeable pad at root and changeable pad at shroud as shown in figure 11a, 11b includes the following steps.

[0030] As the present invention is a replacement of root base pad and shroud base pad, firstly, required height and angle of the resting surface are calculated.

[0031] The calculated height is adjusted in the present assembly by rotating (tightening and loosening) the bolt 700 for height adjustment as per figure 7 and thereby sliding the lower wedge 600 for height adjustment as per figure 6 (2 numbers) and thereby moving lower holder block 200 as per figure 2 and the rotating part 300 for angle adjustment as in figure 3 together.

[0032] The calculated angle as per rhomboid angle of the blade is adjusted by inserting the required angle adjustment wedge 500 as per figure 5 and fastening them with the grub screw 800 for clamping, as per figure 8, as shown in figure 9a, 9b.

[0033] The entire assembly is equivalent to the changeable pad at root and changeable pad at shroud as shown in figure 11a, 11b.

[0034] The assembly is fastened to the angle block as shown in figure 11a, 11b with the help of Standard bolts through counterbore holes shown in the base block 100 as in figure 1.

[0035] It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims.