A roller centralizer and a roller installation method

Abstract

The present invention provides a roller centralizer and a roller installation method, belonging to the technical field of centralizers, to solve the problem that in the prior art, when the roller centralizer is working, the fixing bolts are prone to deformation and fracture; it includes a centralizer body, a groove is provided on the centralizer body, a roller device is embedded in the groove, a fixing groove communicated with the groove is also provided on the centralizer body, and a fixing block abutted against the roller device is arranged in the fixing groove; a waist-shaped hole is provided on the fixing block, a fixing pin is elastically connected in the waist-shaped hole, and a slot for the fixing pin to insert is arranged in the fixing groove. The present invention realizes the fixation of the roller device through the embedded installation of the roller device and the abutting action of the fixing block. Among them, the fixing pin in the fixing block only plays a role in preventing the fixing block from falling off. After the roller device is subjected to an external force, the force will be transmitted to the fixing block and then to the centralizer body by the fixing block, and the fixing pin is less stressed and not easy to break, improving the service life of the centralizer.

Description

Technical Field

[0001] The present invention belongs to the technical field of centralizers, and particularly relates to a roller centralizer and a roller installation method. Background Art

[0002] A roller centralizer is a centralizing tool in oil drilling and production for oil wells. Its function is to play a centralizing role to ensure the smoothness of the drill string and drill pipe during the working process.

[0003] The roller centralizer is characterized in that three freely rotatable rollers are installed on the body. In addition to the function of a conventional centralizer, since the rotating rollers contact the wellbore wall, the friction between the centralizer and the wellbore wall can be greatly reduced. At the same time, for abnormal situations such as frequent wellbore shrinkage and irregular wellbores, the rollers of the roller centralizer can be used to break and trim the rock at the abnormal part of the wellbore wall to form a regular wellbore diameter and improve the drilling quality.

[0004] The installation method of the centralizer roller in the prior art is as Figure 9 shown, and the installation is realized by inserting bolts into the screw holes in the roller device and the centralizer groove.

[0005] The prior art has the following deficiencies:

[0006] Since the rollers of the roller centralizer are mainly subjected to axial forces during operation, the forces will be transmitted to the bolts after the rollers are stressed. Since the bolts are perpendicular to the stress direction, deformation and fracture are likely to occur, reducing the service life of the centralizer. Summary of the Invention

[0007] In view of this, the present invention provides a roller centralizer and a roller installation method to solve the problem in the prior art that when the roller centralizer is working, its rollers are mainly subjected to axial forces, and the forces will be transmitted to the bolts after the rollers are stressed. Since the bolts are perpendicular to the stress direction, deformation and fracture are likely to occur, reducing the service life of the centralizer.

[0008] The technical solution adopted by the present invention is as follows:

[0009] A roller centralizer includes a centralizer body. A groove is provided on the centralizer body, and a roller device is embedded in the groove. A fixing groove communicating with the groove is also provided on the centralizer body, and a fixing block abutting against the roller device is provided in the fixing groove. A waist-shaped hole is provided on the fixing block, the waist-shaped hole is arranged along the width direction of the groove, a fixing pin is elastically connected in the waist-shaped hole, one end of the fixing pin extends out of the waist-shaped hole, and a slot for inserting the fixing pin is provided in the fixing groove.

[0010] In this technical solution, it should be noted that there are specifically three roller devices, and the three roller devices are arranged at equal intervals along the circumferential direction of the centralizer body, with an interval of 120° between two adjacent roller devices. In this solution, the roller devices are embedded in the grooves, and the roller devices are limited by the abutting method of the fixing blocks, so that the roller devices are fixed. During specific installation, the roller devices are embedded in the grooves, and the grooves limit the roller devices up and down. Then, the fixing pins are pressed, and the fixing pins contract into the waist-shaped holes. Then, the fixing blocks are inserted into the fixing grooves. At this time, the fixing blocks are in contact with the roller devices, limiting the roller devices left and right, and the fixing pins in the waist-shaped holes are inserted into the slots under the elastic action to prevent the fixing blocks from falling off. In this solution, when the roller devices are subjected to an axial force, the force will be directly transmitted to the fixing blocks and then to the centralizer body through the fixing blocks. The fixing pins are less stressed and only play a role in preventing the fixing blocks from falling off, and are not prone to deformation and fracture. To sum up, the present invention realizes the fixation of the roller devices through the embedded installation of the roller devices and the abutting action of the fixing blocks. The fixing pins in the fixing blocks only play a role in preventing the fixing blocks from falling off. When the roller devices are subjected to external forces, the forces will be transmitted to the fixing blocks and then to the centralizer body by the fixing blocks. The fixing pins are less stressed and are not prone to fracture, improving the service life of the centralizer.

[0011] Preferably, there are two waist-shaped holes, and the two waist-shaped holes are symmetrically arranged with the longitudinal section passing through the midline of the fixing block as the symmetry plane, and each waist-shaped hole is provided with a fixing pin.

[0012] In this technical solution, it should be noted that the anti-falling effect of the fixing block can be further improved by the two symmetrically arranged fixing pins.

[0013] Preferably, the length of the slot is greater than the sum of the diameters of the two fixing pins.

[0014] In this technical solution, it should be noted that since the length of the slot is greater than the sum of the diameters of the two fixing pins, that is to say, the fixing pins have sufficient movement clearance in the slot. Therefore, when the roller devices are subjected to an axial force and transmitted to the fixing blocks, the fixing blocks move after being subjected to a large external force, and at this time, the fixing pins can move in the slots to prevent themselves from being stressed, that is, the fixing pins basically do not bear external forces, further improving the service life of the fixing pins.

[0015] Preferably, there are two abutting surfaces at the bottom of the fixing groove, and the two abutting surfaces are respectively located on both sides of the two fixing pins, and each abutting surface slopes upward along the direction away from the adjacent fixing pin.

[0016] In this technical solution, it should be noted that after the roller device is subjected to axial force, if the slot is linear and has no abutment surfaces on the left and right sides, then there is no limiting effect on the left and right sides. At this time, although the fixed pin will offset the force through its displacement, all external forces are distributed in the axial direction of the stabilizer body, which will cause greater damage to the stabilizer. In this solution, since the abutment surface is provided, after the fixed pin is displaced, the arc surface will squeeze the fixed pin, so that part of the force is distributed in the axial direction of the fixed pin, and the fixed pin is distributed in the height direction of the spring and the fixed block, so that the entire device cooperates in the force, and the life of the stabilizer is further improved.

[0017] Preferably, the fixing pin comprises a spring and two pins, and spring grooves are respectively provided at opposite ends of the two pins; the two ends of the spring are respectively connected to the bottoms of the two spring grooves; the ends of the two pins respectively extend out of the waist-shaped hole and cooperate with the slots on both sides of the fixing groove.

[0018] In this technical solution, it should be noted that the two pins can be retracted by means of the spring, and the spring groove is used to install and limit the spring.

[0019] Preferably, a pin extraction hole communicating with the waist-shaped hole is provided on the centralizer body.

[0020] In this technical solution, it should be noted that when the fixing block needs to be removed, the staff can use pliers to insert into the pin extraction hole, so that the two pins are retracted into the waist-shaped hole, thereby releasing the limit on the fixing block, and then the fixing block can be pulled out.

[0021] Preferably, the roller device includes a roller and two clamping blocks rotatably connected to the two ends of the roller, each clamping block is provided with clamping strips on both sides in the width direction, and the groove is provided with two clamping grooves spaced apart and cooperating with the clamping strips on the two clamping blocks, and the clamping strips are slidably embedded in the clamping grooves.

[0022] In this technical solution, it should be noted that, in this solution, the roller device is embedded in the groove through the cooperation of the card strip and the card slot, wherein the card slot realizes the upper and lower limit of the card strip, and the card strip and the card block are integrally formed.

[0023] A roller installation method for a roller centralizer, comprising:

[0024] Step 1: Insert the card strip of one of the card blocks into the card slot in the groove, and the card block is located at the end of the groove away from the fixed groove;

[0025] Step 2: Place the roller in the groove and connect one end of the roller to the block in step 1;

[0026] Step 3: Insert the card strip of another card block into another card slot in the groove, and connect the other end of the roller to the card block to complete the installation of the roller device;

[0027] Step 4: Press both ends of the fixing pin in the waist-shaped hole so that both ends of the fixing pin are compressed into the waist-shaped hole under the action of the spring. Snap the fixing block into the fixing groove. Both ends of the fixing pin are reset under the elastic force of the spring and snap into the slot, so that the fixing block is fixed. The fixing block realizes the fixation of the roller device through the limiting action on the roller device.

[0028] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0029] 1. The present invention realizes the fixation of the roller device through the embedded installation of the roller device and the abutting action of the fixing block. The fixing pin in the fixing block only plays a role in preventing the fixing block from falling off. After the roller device is subjected to an external force, the force will be transmitted to the fixing block and then from the fixing block to the centralizer body. The fixing pin is less stressed and not easily broken, improving the life of the centralizer;

[0030] 2. In the present invention, since the length of the slot is greater than the sum of the diameters of the two fixing pins, that is to say, the fixing pin has sufficient movement clearance in the slot. Therefore, when the roller device is subjected to an axial force and transmitted to the fixing block, the fixing block moves after being subjected to a large external force. At this time, the fixing pin can move in the slot to prevent itself from being stressed, that is, the fixing pin basically does not bear the external force, further improving the life of the fixing pin;

[0031] 3. In the present invention, due to the provision of the abutting surface, after the fixing pin is displaced, the abutting surface of the arc surface will squeeze the fixing pin, so that a part of the force is distributed to the axial direction of the fixing pin and is distributed by the fixing pin to the height direction of the spring and the fixing block, enabling the entire device to cooperate and bear the force together, further improving the life of the centralizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be described by way of examples with reference to the accompanying drawings, wherein:

[0033] Figure 1 is the three-dimensional structure schematic diagram of the present invention;

[0034] Figure 2 is the three-dimensional structure schematic diagram of the centralizer body with the fixing block hidden;

[0035] Figure 3 is the three-dimensional structure schematic diagram of the centralizer body with the fixing block and the roller device hidden;

[0036] Figure 4 is Figure 1 the structural schematic diagram after sectional view along A-A;

[0037] Figure 5 is a perspective structural view of the fixing block and roller device of the present invention;

[0038] Figure 6 is a perspective structural view of the fixing block of the present invention after hiding the fixing pin;

[0039] Figure 7 is Figure 2 an enlarged view of part A in

[0040] Figure 8 is Figure 3 a perspective view of

[0041] Figure 9 is a perspective structural view of a roller aligner in the prior art.

[0042] Reference numerals

[0043] 10 - aligner body, 11 - fixing groove, 111 - slot, 112 - abutting surface, 12 - groove, 121 - clamping groove, 13 - pin - pulling hole, 20 - fixing block, 21 - fixing pin, 211 - pin, 212 - spring, 213 - spring groove, 22 - waist - shaped hole, 30 - roller, 31 - clamping block, 311 - clamping strip. Detailed implementation manners

[0044] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. The components of the embodiments of the present invention usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0046] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0047] It should be noted that: similar reference numerals and letters denote similar items in the following accompanying drawings. Therefore, once an item is defined in one accompanying drawing, it does not need to be further defined and explained in subsequent accompanying drawings.

[0048] In the present invention, unless otherwise clearly specified or limited, the first feature being "above" or "below" the second feature may include direct contact between the first and second features, or may include contact between the first and second features not being direct but through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "beneath" and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the horizontal height of the first feature is less than that of the second feature.

[0049] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0050] Example 1

[0051] Such as Figures 1 - 7 And Figure 9As shown in the figure, an embodiment of the present invention discloses a roller centralizer, which includes a centralizer body 10. A groove 12 is provided on the centralizer body 10, and a roller device is embedded in the groove 12. A fixing groove 11 communicating with the groove 12 is further provided on the centralizer body 10, and a fixing block 20 abuting against the roller device is provided in the fixing groove 11; a waist-shaped hole 22 is provided on the fixing block 20, the waist-shaped hole 22 is arranged along the width direction of the groove 12, and a fixing pin 21 is elastically connected in the waist-shaped hole 22. One end of the fixing pin 21 extends out of the waist-shaped hole 22, and a slot 111 for the fixing pin 21 to insert is provided in the fixing groove 11. It should be noted that the roller device is specifically three, and the three roller devices are arranged at equal intervals along the circumference of the centralizer body 10, and the adjacent two roller devices are spaced 120°. In this solution, the roller device is embedded in the groove 12, and the roller device is limited by abutting against the fixing block 20, so that the roller device is fixed. During specific installation, the roller device is embedded in the groove 12, and the groove 12 limits the roller device up and down. Then, the fixing pin 21 is pressed, and the fixing pin 21 contracts into the waist-shaped hole 22. Then, the fixing block 20 is inserted into the fixing groove 11. At this time, the fixing block 20 abuts against the roller device, limiting the roller device left and right, and the fixing pin 21 in the waist-shaped hole 22 is inserted into the slot 111 under the elastic action to prevent the fixing block 20 from falling off; in this solution, when the roller device is subjected to an axial force, it will be directly transmitted to the fixing block 20 and then transmitted to the centralizer body 10 through the fixing block 20, while the fixing pin 21 is less stressed and only plays a role in preventing the fixing block 20 from falling off, and is not prone to deformation and fracture; in summary, the present invention realizes the fixation of the roller device through the embedded installation of the roller device and the abutting action of the fixing block 20. The fixing pin 21 in the fixing block 20 only plays a role in preventing the fixing block 20 from falling off. After the roller device is subjected to an external force, the force will be transmitted to the fixing block 20, and then transmitted to the centralizer body 10 by the fixing block 20, while the fixing pin 21 is less stressed and not prone to fracture, improving the service life of the centralizer.

[0052] As Figure 6 shown, in this embodiment, there are two waist-shaped holes 22, and the two waist-shaped holes 22 are symmetrically arranged with the longitudinal section passing through the center line of the fixing block 20 as the symmetry plane, and a fixing pin 21 is provided in each waist-shaped hole 22. It should be noted that the anti-falling effect of the fixing block 20 can be further improved by the two symmetrically arranged fixing pins 21.

[0053] As Figure 2 and Figure 3As shown in the figure, in this embodiment, the length of the slot 111 is greater than the sum of the diameters of the two fixing pins 21. It should be noted that since the length of the slot 111 is greater than the sum of the diameters of the two fixing pins 21, that is to say, the fixing pins 21 have sufficient moving clearance in the slot 111. Therefore, when the roller device is subjected to an axial force and transmitted to the fixing block 20, the fixing block 20 moves after being subjected to a large external force. At this time, the fixing pins 21 can move in the slot 111 to prevent themselves from being stressed, that is, the fixing pins 21 basically do not bear external forces, further improving the service life of the fixing pins 21.

[0054] As Figure 2 and Figure 3 and Figure 7 As shown in the figure, in this embodiment, two abutting surfaces 112 are provided at the bottom of the fixing groove 11. The two abutting surfaces 112 are respectively located on both sides of the two fixing pins 21, and each abutting surface 112 slopes upward in a direction away from the adjacent fixing pin 21. It should be noted that after the roller device is subjected to an axial force, if the card slot 121 is linear and there are no abutting surfaces 112 on the left and right sides, then there is no limiting effect on the left and right at this time. Although the fixing pins 21 will offset the force through their displacement, all external forces are distributed to the axial direction of the centralizer body 10, which will cause greater damage to the centralizer. In this solution, due to the provision of the abutting surfaces 112, after the fixing pins 21 are displaced, the arc surface will squeeze the fixing pins 21, so that part of the force is distributed to the axial direction of the fixing pins 21 and is distributed by the fixing pins 21 to the height direction of the spring 212 and the fixing block 20, enabling the entire device to cooperate and bear the force together, further improving the service life of the centralizer.

[0055] As Figure 4 As shown in the figure, in this embodiment, the fixing pin 21 includes a spring 212 and two pin studs 211. Spring grooves 213 are respectively provided at the opposite ends of the two pin studs 211; the two ends of the spring 212 are respectively connected to the bottoms of the two spring grooves 213; the ends of the two pin studs 211 respectively extend outside the waist-shaped holes 22 and cooperate with the slots 111 on both sides of the fixing groove 11. It should be noted that the two pin studs 211 can be contracted by the spring 212, and the spring grooves 213 are used for installing and limiting the spring 212.

[0056] As Figure 4 As shown in the figure, in this embodiment, a pin extraction hole 13 communicating with the waist-shaped holes 22 is provided on the centralizer body 10. It should be noted that when it is necessary to take out the fixing block 20, the staff can insert a large pliers into the pin extraction hole 13 to make the two pin studs 211 contract into the waist-shaped holes 22, release the limit on the fixing block 20, and then the fixing block 20 can be pulled out.

[0057] As Figure 3 andFigure 5 and Figure 9 As shown in Figure 9 , in this embodiment, the roller device includes a roller 30 and two clamping blocks 31 rotatably connected to both ends of the roller 30. On both sides in the width direction of each clamping block 31, there are clamping strips 311. In the groove 12, there are two card slots 121 arranged at intervals and cooperating with the clamping strips 311 on the two clamping blocks 31. The clamping strips 311 are slidably embedded in the card slots 121. It should be noted that in this solution, the roller device is embedded and connected to the groove 12 through the cooperation of the clamping strips 311 and the card slots 121. Among them, the card slots 121 realize the up and down limit of the clamping strips 311, and the clamping strips 311 are integrally formed with the clamping blocks 31.

[0058] The working principle of this embodiment is as follows:

[0059] First, embed the clamping strip 311 of one of the clamping blocks 31 into the card slot 121 in the groove 12, and the position of this clamping block 31 is at the end of the groove 12 away from the fixed slot 11; then place the roller 30 into the groove 12 and connect one end of the roller 30 to the installed clamping block 31; then embed the clamping strip 311 of the other clamping block 31 into the other card slot 121 in the groove 12, and connect the other end of the roller 30 to this clamping block 31 to complete the installation of the roller device; finally, press both ends of the fixing pin 21 in the waist-shaped hole 22, so that both ends of the fixing pin 21 are compressed into the waist-shaped hole 22 under the action of the spring 212, and then snap the fixing block 20 into the fixed slot 11. Both ends of the fixing pin 21 are reset under the elastic force of the spring 212 and snap into the slot 111, so that the fixing block 20 is fixed, and the fixing block 20 realizes the fixing of the roller device through the limiting action on the roller device.

[0060] Embodiment 2

[0061] Based on Embodiment 1, this embodiment proposes a method for installing a roller of a roller aligner, including:

[0062] Step 1: Embed the clamping strip 311 of one of the clamping blocks 31 into the card slot 121 in the groove 12, and the position of this clamping block 31 is at the end of the groove 12 away from the fixed slot 11;

[0063] Step 2: Place the roller 30 into the groove 12 and connect one end of the roller 30 to the clamping block 31 in Step 1;

[0064] Step 3: Embed the clamping strip 311 of the other clamping block 31 into the other card slot 121 in the groove 12, and connect the other end of the roller 30 to this clamping block 31 to complete the installation of the roller device;

[0065] Step 4: Press both ends of the fixing pin 21 in the waist-shaped hole 22, so that both ends of the fixing pin 21 are compressed into the waist-shaped hole 22 under the action of the spring 212. Then, snap the fixing block 20 into the fixing groove 11. Both ends of the fixing pin 21 are reset under the elastic force of the spring 212 and snap into the slot 111, so that the fixing block 20 is fixed. The fixing block 20 realizes the fixation of the roller device through the limiting action on the roller device.

[0066] The circuits, electronic components and modules involved are all prior arts and can be fully realized by those skilled in the art without further elaboration. The content protected by the present invention does not involve the improvement of software and methods either.

[0067] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other.

[0068] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A roller centralizer, comprising a centralizer body (10), wherein a groove (12) is provided on the centralizer body (10), and is characterized in that, A roller device is embedded in the groove (12), and a fixing groove (11) communicating with the groove (12) is further provided on the centralizer body (10), and a fixing block (20) abutting against the roller device is arranged in the fixing groove (11); A waist-shaped hole (22) is provided on the fixing block (20), the waist-shaped hole (22) is arranged along the width direction of the groove (12), a fixing pin (21) is elastically connected in the waist-shaped hole (22), one end of the fixing pin (21) extends out of the waist-shaped hole (22), and a slot (111) for the fixing pin (21) to insert is arranged in the fixing groove (11); The length of the slot (111) is greater than the sum of the diameters of the two fixing pins (21); There are two waist-shaped holes (22), and the two waist-shaped holes (22) are symmetrically arranged with the longitudinal section passing through the midline of the fixing block (20) as the symmetry plane, and a fixing pin (21) is arranged in each waist-shaped hole (22); Two abutting surfaces (112) are arranged at the bottom of the fixing groove (11), the two abutting surfaces (112) are respectively located on both sides of the two fixing pins (21), and each abutting surface (112) slopes upward along the direction away from the adjacent fixing pin (21).

2. The roller aligner according to claim 1, wherein, The fixing pin (21) includes a spring (212) and two pin studs (211), and spring grooves (213) are respectively arranged at the opposite ends of the two pin studs (211); the two ends of the spring (212) are respectively connected to the bottoms of the two spring grooves (213); the ends of the two pin studs (211) respectively extend out of the waist-shaped hole (22) and cooperate with the slots (111) on both sides of the fixing groove (11).

3. A roller aligner according to claim 1, characterized in that, A pin-pulling hole (13) communicating with the waist-shaped hole (22) is provided on the centralizer body (10).

4. A roller centralizer according to any one of claims 2, characterized in that The roller device includes a roller (30) and two clamping blocks (31) rotatably connected to both ends of the roller (30), clamping strips (311) are arranged on both sides in the width direction of each clamping block (31), and two clamping grooves (121) cooperating with the clamping strips (311) on the two clamping blocks (31) are arranged at intervals in the groove (12), and the clamping strips (311) are slidably embedded in the clamping grooves (121).

5. A roller centralizer according to any one of claims 1-3, characterized in that, There are three roller devices, and the three roller devices are equidistantly arranged at intervals along the circumferential direction of the centralizer body (10).

6. A method for installing a roller of a roller centralizer, characterized in that Implemented by using a roller centralizer according to claim 4, including: Step 1: Embed the clamping strip (311) of one clamping block (31) into the clamping groove (121) in the groove (12), and the position of this clamping block (31) is located at one end of the groove (12) far from the fixing groove (11); Step 2: Place the roller (30) in the groove (12), and connect one end of the roller (30) to the clamping block (31) in Step 1; Step 3: Embed the clamping strip (311) of the other clamping block (31) into the other clamping groove (121) in the groove (12), and connect the other end of the roller (30) to this clamping block (31) to complete the installation of the roller device; Step 4: Press both ends of the fixing pin (21) in the waist-shaped hole (22), so that both ends of the fixing pin (21) are compressed into the waist-shaped hole (22) under the action of the spring (212). Then, snap the fixing block (20) into the fixing groove (11). Both ends of the fixing pin (21) are reset under the elastic force of the spring (212) and snap into the slot (111), so that the fixing block (20) is fixed. The fixing block (20) fixes the roller device by limiting the roller device.

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