Wind power generation cavity bearing platform foundation anchor bolt hole positioning device and positioning method thereof

Abstract

The invention discloses a wind power generation cavity bearing platform foundation anchor bolt hole positioning device and a positioning method thereof, and relates to the field of wind power generation foundation bearing platforms, the wind power generation cavity bearing platform foundation anchor bolt hole positioning device comprises two semicircular bases and a plurality of pre-buried corrugated pipes, the two semicircular bases are spliced to form an annular base and are detachably connected through an insertion fixing piece, and the pre-buried corrugated pipes are embedded in the annular base; a plurality of adjusting grooves are formed in the semicircular base in a penetrating mode. The embedded corrugated pipe is fixed in the upper pipe clamp and the lower pipe clamp, the adjusting transverse rod is lifted according to data, so that the protruding block is not connected with the U-shaped groove in a clamped mode, the adjusting cylinder is moved to a proper position in the positioning groove and then pressed downwards, the protruding block is clamped into the other U-shaped groove, position adjustment is completed, then the adjusting transverse rod is inclined, and the protruding block rotates in the U-shaped groove. After the pre-buried corrugated pipe is driven to incline by 1.37 degrees, the extrusion block and the adjusting cylinder are extruded and fixed, the position and the inclination degree of the pre-buried corrugated pipe can be adjusted according to flange plate hole site data, anchor bolt positioning is more accurate, and the installation precision and the construction efficiency of equipment are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power foundation caissons, and particularly relates to a positioning device and a positioning method for anchor bolt holes of a wind power cavity caisson foundation. Background Art

[0002] The foundation structure of a wind turbine caisson is usually a reinforced concrete structure, generally circular or polygonal. It has a large size to provide sufficient support area and stability. The bottom of the foundation will be treated according to geological conditions, and pile foundations or other forms of foundation reinforcement measures may be set to tightly connect the caisson with the foundation, ensuring that it can bear the huge loads of the wind turbine. The wind turbine caisson is formed by pouring concrete with a steel reinforcement cage on the ground to form a base, and annularly distributed anchor bolts need to be configured on the base for docking with the bottom tower barrel. During the pre-embedding and pouring process of the anchor bolts, due to adverse factors such as equipment vibration and concrete flow, the position of the anchor bolts fixed on the formwork will shift. During the later docking, rework and adjustment work are required, and the pre-embedding accuracy of the anchor bolts is poor, and the construction efficiency is slow. Summary of the Invention

[0003] The purpose of the present invention is to provide a positioning device and a positioning method for anchor bolt holes of a wind power cavity caisson foundation to solve the above problems, as elaborated below.

[0004] To achieve the above purpose, the present invention provides the following technical solutions: A positioning device for anchor bolt holes of a wind power cavity caisson foundation provided by the present invention includes two semi-circular bases and a plurality of pre-embedded corrugated pipes. The two semi-circular bases are spliced to form an annular base and are detachably connected by plug-in fixing parts. A plurality of adjustment grooves are penetrated through the semi-circular bases, and an adjustment cross bar for adjusting radially along the semi-circular base and deflecting is arranged in each adjustment groove. A clamping and fixing part for fixing the inclination angle of the adjustment cross bar is arranged on the upper side of each adjustment groove. A pipe clamp for fixing the pre-embedded corrugated pipe is arranged at one end of each adjustment cross bar close to the inner arc of the semi-circular base.

[0005] Preferably, an L-shaped lower support rod is arranged at one end of each adjustment cross bar close to the outer arc of the semi-circular base. A plug-in fixing sleeve for fixing the upper end of the vertical part of the L-shaped lower support rod is arranged at the end of the adjustment cross bar. A pipe clamp is also fixedly connected to the end of the horizontal part of the L-shaped lower support rod. A triangular reinforcing rod is fixedly connected at the corner of the L-shaped lower support rod.

[0006] Preferably, the plug-in fixing sleeve includes an insert fixedly connected to the end of the adjustment cross bar. The L-shaped lower support rod is inserted and adapted to the insert. A jack is opened on the side wall of the insert, and a bolt I is inserted into the jack. A bolt hole I threadedly adapted to the bolt I is opened on the side wall of the L-shaped lower support rod.

[0007] Preferably, the plug-in fixing member includes two connecting plates fixedly connected to both ends of one of the semi-circular bases. Each end of each connecting plate is fixedly connected with a cylindrical plug rod. Two slots adapted for plugging and connecting with the connecting plates and the cylindrical plug rods are provided at both ends of the other semi-circular base, and a bolt connecting member I for fixing the cylindrical plug rod is provided in the slots.

[0008] Preferably, the bolt connecting member I includes a bolt II rotatably connected in the cylindrical plug rod, and a bolt hole II threadedly connected with the bolt II is provided at the inner bottom of the slot.

[0009] Preferably, a fastening wire is fixedly connected to the open end of the pipe clamp, and a winding column is rotatably connected to the other open end of the pipe clamp. A through hole adapted for plugging and connecting with the fastening wire is provided through the winding column.

[0010] Preferably, positioning grooves are provided on both side walls of the adjustment groove. A plurality of U-shaped grooves are provided below each positioning groove. An adjustment cylinder is fixedly connected to the middle of the adjustment cross bar, and the length of the adjustment cylinder is adapted to the width of the adjustment groove. Convex blocks adapted for clamping connection with the U-shaped grooves are fixedly connected to both ends of the adjustment cylinder. Through grooves for the adjustment cross bar to move and adjust are provided at both ends of the adjustment groove.

[0011] Preferably, the clamping and fixing member includes a cross plate. Extrusion blocks adapted for abutting against the adjustment cylinder are fixedly connected to both sides of the bottom surface of the cross plate. Bolts III are rotatably connected to both ends of the bottom surface of the cross plate. A plurality of bolt holes III threadedly connected with the bolts III are provided on the upper side wall of the positioning groove, and the plurality of bolt holes III correspond to the plurality of U-shaped grooves one by one. Tooth teeth engaged with each other are provided on the contact surfaces between the extrusion blocks and the adjustment cylinder.

[0012] Preferably, an anchor backing plate is fixedly connected to the bottom end of the embedded corrugated pipe, and spiral stirrups are fixedly connected to the bottom of the embedded corrugated pipe.

[0013] A positioning method for an anchor bolt hole positioning device of a wind power generation cavity cap foundation includes the following steps: S1: Horizontally place the two semi-circular bases on the surface of the casting formwork, and fixedly install them in butt joint through the plug-in fixing member. At this time, the two semi-circular bases form a ring. Fix the two semi-circular bases to the surface of the casting formwork, and then fix the embedded corrugated pipe in the upper and lower pipe clamps; S2: Subsequently, obtain the hole position data of the flange of the wind power generation tower barrel base. Lift the adjustment cross bar according to the data so that the convex block is not clamped with the U-shaped groove. Move the adjustment cylinder in the positioning groove to a suitable position and then press down to make the convex block snap into another U-shaped groove to complete the position adjustment. Then tilt the adjustment cross bar, and the convex block rotates in the U-shaped groove to drive the embedded corrugated pipe to tilt by 1.37°, and then squeeze and fix the extrusion block and the adjustment cylinder; S3: Then pour concrete into the formwork. After it solidifies, embed the corrugated pipe in the cavity cap foundation to facilitate the insertion and fixation of the anchor bolts. Then remove the pouring formwork and the semi-circular base together, and remove the socket from the upper end of the L-shaped lower support rod to complete the positioning of the anchor bolts.

[0014] The beneficial effects are as follows: By fixing the embedded corrugated pipe in the upper and lower pipe clamps, adjusting the cross bar upward according to the data so that the convex block is not engaged with the U-shaped groove, moving the adjusting cylinder in the positioning groove to a suitable position and then pressing it down to make the convex block snap into another U-shaped groove to complete the position adjustment. Then tilt the adjusting cross bar, and the convex block rotates in the U-shaped groove, driving the embedded corrugated pipe to tilt by 1.37°. After that, squeeze and fix the extrusion block and the adjusting cylinder, and the position and inclination of the embedded corrugated pipe can be adjusted according to the flange hole position data, making the positioning of the anchor bolts more accurate, improving the installation accuracy of the equipment and the construction efficiency.

[0015] The L-shaped lower support rod, the triangular reinforcing rod and the pipe clamp can be more stable and firm when fixing the embedded corrugated pipe, avoiding the vibration and dislocation of the embedded corrugated pipe during the pouring process. At the same time, after the pouring is completed, the semi-circular base can be removed from the L-shaped lower support rod for turnover use.

[0016] After the cylindrical insertion rod and the connecting plate are inserted into the slot, the two semi-circular bases are butted against each other to form a ring. Then rotate the second bolt to fix it in the second bolt hole to complete the butt joint and fixation. On the contrary, the two semi-circular bases can be disassembled for convenient transfer and transportation.

[0017] The spiral reinforcement shows excellent stability, is firm and solid. During the concrete pouring process, it can ensure that the finished steel bar withstands severe disturbance, collision and trampling without distortion or deformation, and improves the connection strength. The anchor backing plate can improve the bearing capacity of the anchorage area, and the stress distribution during loading is relatively uniform and not prone to failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 is a three-dimensional view of the present invention; Figure 2 is a disassembled three-dimensional view of the L-shaped lower support rod of the present invention; Figure 3 is a partial sectional three-dimensional view of the semi-circular base of the present invention; Figure 4It is a partial exploded perspective view of the semi-circular base of the present invention; Figure 5 It is an exploded perspective view of the plug-in fixing part of the present invention.

[0020] The reference numerals are explained as follows: 1. Semi-circular base; 2. Embedded corrugated pipe; 201. Anchor plate; 202. Spiral stirrup; 3. Adjusting cross bar; 301. Adjusting cylinder; 302. Protrusion; 303. Positioning groove; 304. Horizontal plate; 305. Extrusion block; 306. U-shaped groove; 307. Through groove; 308. Bolt III; 309. Bolt hole III; 4. Pipe clamp; 401. Fastening wire; 402. Winding column; 403. Perforation; 5. Plug-in fixing part; 501. Connecting plate; 502. Cylindrical plug; 503. Slot; 504. Bolt II; 505. Bolt hole II; 6. Plug-in fixing sleeve; 601. Inserting sleeve; 602. Bolt hole I; 603. Insertion hole; 604. Bolt I; 7. L-shaped lower support rod; 8. Triangular reinforcing rod; 9. Adjusting groove. Specific embodiments

[0021] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation manners obtained by those of ordinary skill in the art without creative efforts fall within the scope protected by the present invention.

[0022] See Figures 1-5 As shown, the present invention provides a positioning device for anchor bolt holes of a wind power cavity cap foundation, which includes two semi-circular bases 1 and a plurality of embedded corrugated pipes 2. The two semi-circular bases 1 are spliced to form an annular base and are detachably connected by a plug-in fixing part 5. A plurality of adjusting grooves 9 are formed through the semi-circular bases 1, and an adjusting cross bar 3 for adjusting radially along the semi-circular base 1 and deflecting is arranged in each adjusting groove 9. A clamping and fixing part for fixing the inclination angle of the adjusting cross bar 3 is arranged on the upper side of each adjusting groove 9. A pipe clamp 4 for fixing the embedded corrugated pipe 2 is arranged at one end of each adjusting cross bar 3 close to the inner arc of the semi-circular base 1.

[0023] As an optional implementation manner, an L-shaped lower support rod 7 is arranged at one end of each adjusting cross bar 3 close to the outer arc of the semi-circular base 1, and a plug-in fixing sleeve 6 for fixing the upper end of the vertical part of the L-shaped lower support rod 7 is arranged at the end of the adjusting cross bar 3. A pipe clamp 4 is also fixedly connected to the end of the horizontal part of the L-shaped lower support rod 7. A triangular reinforcing rod 8 is fixedly connected to the corner of the L-shaped lower support rod 7. The L-shaped lower support rod 7, the triangular reinforcing rod 8 and the pipe clamp 4 can be more stable and firm when fixing the embedded corrugated pipe 2, and at the same time, the semi-circular base 1 can be removed from the L-shaped lower support rod 7 for turnover use after pouring is completed.

[0024] Refer to Figure 2 As shown, the plug-in fixing sleeve 6 includes a socket 601 fixedly connected to the end of the adjusting cross bar 3, and the L-shaped lower support rod 7 is in plug-in fit with the socket 601. A jack 603 is formed on the side wall of the socket 601, and a first bolt 604 is inserted into the jack 603. A first bolt hole 602 threadedly adapted to the first bolt 604 is formed on the side wall of the L-shaped lower support rod 7. After inserting the L-shaped lower support rod 7 into the socket 601, the first bolt 604 is inserted into both the jack 603 and the first bolt hole 602 and rotated to complete the connection and fixation between the two. After the L-shaped lower support rod 7 is pre-buried and fixed in the concrete base, the socket 601 can be removed from the L-shaped lower support rod 7, facilitating the turnover and use of the semi-circular base 1.

[0025] Refer to Figure 5 As shown, the plug-in fixing member 5 includes two connecting plates 501 fixedly connected to both ends of one of the semi-circular bases 1. A cylindrical plug 502 is fixedly connected to the end of each connecting plate 501. Two slots 503 adapted for plugging the connecting plates 501 and the cylindrical plugs 502 are formed at both ends of the other semi-circular base 1. And a first bolt connecting member for fixing the cylindrical plug 502 is provided in the slot 503. The first bolt connecting member includes a second bolt 504 rotatably connected in the cylindrical plug 502. A second bolt hole 505 threadedly connected to the second bolt 504 is formed at the inner bottom of the slot 503. After the cylindrical plug 502 and the connecting plate 501 are inserted into the slot 503, the two semi-circular bases 1 are butted against each other to form a ring. Then the second bolt 504 is rotated and fixed in the second bolt hole 505 to complete the butt joint and fixation.

[0026] Refer to Figure 4 As shown, a fastening wire 401 is fixedly connected to the open end of the pipe clamp 4. The other open end of the pipe clamp 4 is rotatably connected to a winding column 402. A through hole 403 adapted for plugging the fastening wire 401 is formed through the winding column 402. After the pre-buried corrugated pipe 2 is inserted into the pipe clamp 4, the fastening wire 401 is inserted into the through hole 403. Then the winding column 402 is rotated to wind the fastening wire 401 around the surface of the winding column 402 in circles to complete the clamping and fixing of the opening of the pipe clamp 4.

[0027] Refer to Figures 3-4As shown in the figure, positioning grooves 303 are formed on both side walls of the adjusting groove 9. A plurality of U-shaped grooves 306 are formed below each positioning groove 303. A middle part of the adjusting cross bar 3 is fixedly connected with an adjusting cylinder 301, and a length of the adjusting cylinder 301 is adapted to a width of the adjusting groove 9. Both ends of the adjusting cylinder 301 are fixedly connected with bumps 302 which are adapted to be clamped with the U-shaped grooves 306. Through grooves 307 for the adjusting cross bar 3 to move and adjust are formed at both ends of the adjusting groove 9. When moving the position of the adjusting cross bar 3, lift the adjusting cross bar 3. At this time, the bump 302 is not clamped with the U-shaped groove 306. After the bump 302 moves to a proper position in the positioning groove 303, press down the adjusting cross bar 3 to make the bump 302 snap into another U-shaped groove 306, thereby completing the position adjustment of the embedded corrugated pipe 2.

[0028] As an optional implementation manner, the clamping and fixing member includes a cross plate 304. Both sides of a bottom surface of the cross plate 304 are fixedly connected with extrusion blocks 305 which are adapted to abut against the adjusting cylinder 301. Both ends of the bottom surface of the cross plate 304 are rotatably connected with bolts three 308. A plurality of bolt holes three 309 which are threadedly connected with the bolts three 308 are formed on an upper side wall of the positioning groove 303, and the plurality of bolt holes three 309 correspond to the plurality of U-shaped grooves 306 one by one. Tooth profiles which are meshed with each other are arranged on contact surfaces of the extrusion blocks 305 and the adjusting cylinder 301. After the adjusting cross bar 3 inclines, rotate the bolts three 308 in the bolt holes three 309. At this time, the cross plate 304 drives the two extrusion blocks 305 to move downward, and the tooth profiles on their surfaces are meshed with the tooth profiles on the surface of the adjusting cylinder 301, thereby completing the fixing of the inclination angle of the adjusting cylinder 301 and the adjusting cross bar 3, so as to adjust the inclination angle of the embedded corrugated pipe 2.

[0029] Refer to Figure 2 As shown in the figure, a bottom end of the embedded corrugated pipe 2 is fixedly connected with an anchor backing plate 201, and a spiral rib 202 is fixedly connected to a bottom of the embedded corrugated pipe 2. The stability of the spiral rib 202 is remarkably excellent, and it is firm and reliable. During the concrete pouring process, it can ensure that the steel bar finished product can withstand severe disturbance, collision and trampling without deformation, and improve the connection strength. The anchor backing plate 201 can improve the bearing capacity of the anchorage area, and the stress distribution during bearing is relatively uniform and it is not easy to be damaged.

[0030] The present invention further provides a positioning method for a positioning device of an anchor bolt hole of a wind power generation cavity cap foundation, including the following steps: Place the two semi-circular bases 1 horizontally on the surface of the casting formwork. Insert the cylindrical insertion rod 502 and the connecting plate 501 into the slot 503, and then rotate the second bolt 504 to thread it with the second bolt hole 505. At this time, the two semi-circular bases 1 form a ring, and fix the two semi-circular bases 1 to the surface of the casting formwork. Then, fix the embedded corrugated pipe 2 in the upper and lower pipe clamps 4. Subsequently, obtain the hole position data of the base flange of the wind power tower barrel, adjust the cross bar 3 upward according to the data, so that the convex block 302 is not engaged with the U-shaped groove 306. After moving the adjusting cylinder 301 to a suitable position in the positioning groove 303 and pressing it down, make the convex block 302 snap into another U-shaped groove 306 to complete the position adjustment. Then, tilt the adjusting cross bar 3, and the convex block 302 rotates in the U-shaped groove 306, driving the embedded corrugated pipe 2 to tilt by 1.37°. Then, fix the extrusion block 305 and the adjusting cylinder 301 by extrusion. Pour concrete into the formwork. After solidification, the embedded corrugated pipe 2 is embedded in the cavity cap foundation, which is convenient for inserting and fixing anchor bolts. Then, remove the casting formwork and the semi-circular base 1 together, and remove the socket 601 from the upper end of the L-shaped lower support rod 7 to complete the positioning of the anchor bolts.

[0031] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claimed rights.

Claims

1. A wind power generation cavity cap foundation anchor bolt hole positioning device, comprising two semicircular bases and a plurality of pre-buried corrugated pipes, characterized in that: The two semicircular bases are spliced ​​together to form an annular base and are detachably connected by plug-in fixings. A plurality of adjustment grooves are penetrated through the semicircular base, and each adjustment groove is provided with an adjustment cross bar for radially adjusting and deflecting the semicircular base. The upper side of each adjustment groove is provided with a clamping fixing for fixing the inclination angle of the adjustment cross bar, and each of the adjustment cross bars is provided with a pipe clamp for fixing the embedded corrugated pipe at one end close to the inner arc of the semicircular base.

2. The anchor bolt hole positioning device for a wind power generation cavity cap foundation according to claim 1, characterized in that: Each of the adjusting cross bars is provided with an L-shaped lower support rod at one end close to the outer arc of the semicircular base, and the end of the adjusting cross bar is provided with a plug-in fixing sleeve for fixing the upper end of the vertical part of the L-shaped lower support rod, and the horizontal end of the L-shaped lower support rod is also fixedly connected with a pipe clamp, and the corner of the L-shaped lower support rod is fixedly connected with a triangular reinforcement rod.

3. The anchor bolt hole positioning device for a wind power generation cavity cap foundation according to claim 2, characterized in that: The plug-in fixing sleeve includes a plug-in sleeve fixedly connected to the end of the adjusting cross bar, and the L-shaped lower support rod is plugged and matched with the plug-in sleeve, a plug hole is opened on the side wall of the plug-in sleeve, a bolt is inserted in the plug hole, and a bolt hole is opened on the side wall of the L-shaped lower support rod for thread matching with the bolt.

4. The anchor bolt hole positioning device for a wind power generation cavity cap foundation according to claim 1, characterized in that: The plug-in fixing member includes two connecting plates fixedly connected to the two ends of one of the semicircular bases, and each end of the connecting plate is fixedly connected to a cylindrical plug rod. Two slots that are plug-in compatible with the connecting plates and the cylindrical plug rod are provided at both ends of the other semicircular base, and a bolt connecting member for fixing the cylindrical plug rod is provided in the slot.

5. The anchor bolt hole positioning device for a wind power generation cavity cap foundation according to claim 4, characterized in that: The bolt connector 1 includes a bolt 2 which is rotatably connected to the cylindrical insert rod, and a bolt hole 2 which is threadedly connected to the bolt 2 is provided at the inner bottom of the slot.

6. The anchor bolt hole positioning device for a wind power generation cavity cap foundation according to claim 1, characterized in that: One end of the opening of the pipe clamp is fixedly connected with a fastening wire, and the other end of the opening of the pipe clamp is rotatably connected with a winding column, and a through hole is penetrated through the winding column and is plugged and adapted to the fastening wire.

7. The anchor bolt hole positioning device for a wind power generation cavity cap foundation according to claim 1, characterized in that: The adjustment groove is provided with positioning grooves on both side walls, and a plurality of U-shaped grooves are provided on the lower side of each positioning groove. An adjusting cylinder is fixedly connected to the middle of the adjusting cross bar, and the length of the adjusting cylinder is adapted to the width of the adjusting groove. Both ends of the adjusting cylinder are fixedly connected with protrusions adapted to the U-shaped groove, and both ends of the adjusting groove are provided with through grooves for the movable adjustment of the adjusting cross bar.

8. The anchor bolt hole positioning device for a wind power generation cavity cap foundation according to claim 7, characterized in that: The clamping fixture includes a horizontal plate, and both sides of the bottom surface of the horizontal plate are fixedly connected with extrusion blocks that abut against the adjustment cylinder. Bolts three are rotatably connected to both ends of the bottom surface of the horizontal plate. The upper side wall of the positioning groove is provided with a plurality of bolt holes three that are threadedly connected to the bolts three, and the plurality of bolt holes three correspond one-to-one to the plurality of U-shaped grooves. The contact surfaces of the extrusion block and the adjustment cylinder are provided with teeth that mesh with each other.

9. The anchor bolt hole positioning device for a wind power generation cavity cap foundation according to claim 1, characterized in that: The bottom end of the embedded corrugated pipe is fixedly connected with an anchor plate, and the bottom of the embedded corrugated pipe is fixedly connected with a spiral rib.

10. A positioning method for a wind power generation cavity cap foundation anchor bolt hole positioning device, using the wind power generation cavity cap foundation anchor bolt hole positioning device according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: Place two semicircular bases horizontally on the casting template surface and fix them together by plugging and fastening. At this time, the two semicircular bases form a ring. Fix the two semicircular bases to the casting template surface, and then fix the embedded corrugated pipe in the upper and lower pipe clamps; S2: Then, the hole position data of the flange of the wind turbine tower base is obtained, and the adjustment cross bar is lifted up according to the data so that the protrusion is not engaged with the U-shaped groove. The adjustment cylinder is moved to a suitable position in the positioning groove and then pressed down so that the protrusion is engaged with another U-shaped groove to complete the position adjustment. Then, the adjustment cross bar is tilted, and the protrusion rotates in the U-shaped groove, driving the embedded corrugated pipe to tilt by 1.37°, and then the extrusion block is squeezed and fixed with the adjustment cylinder; S3: Pour concrete into the formwork again, and after solidification, embed the corrugated pipe in the cavity cap foundation to facilitate inserting and fixing anchor bolts therein, then remove the casting formwork and the semicircular base together, and remove the sleeve from the upper end of the L-shaped lower support rod to complete the anchor bolt positioning.

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