Air knife adjusting device for extrusion die head
By designing a wind knife adjustment device for the extrusion die, the complex and time-consuming problem of air knife adjustment is solved, and the rapid and precise adjustment of the wind knife is achieved, and the efficiency and production efficiency of the film fitting the roller are improved.
Patent Information
- Application Number
- CN202420965278.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-07
- Publication Date
- 2025-05-27
- Estimated Expiration
- 2034-05-07
AI Technical Summary
In the production process of plastic film, the adjustment of the air knife is complex and time-consuming, making it difficult to ensure that the film is evenly attached to the roller.
A wind knife adjustment device for an extrusion die is designed, including a translation adjustment mechanism, a lifting adjustment mechanism and an angle adjustment mechanism. Through the cooperation of these mechanisms, the wind knife can quickly and accurately adjust its position and angle.
It realizes rapid and convenient adjustment of the air knife, improves the efficiency of film clinging to the roller, saves cleaning time, and improves production efficiency.
Smart Images
Figure CN222904787U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of plastic film production equipment, and in particular to an air knife adjustment device for an extrusion die head. Background Art
[0002] In the production of plastic film, the film extruded from the extrusion die is cast onto the roller below for cooling and shaping. During this process, the wind knife blows out flowing air to make the film stick to the surface of the roller. However, due to the differences in film thickness, material, production speed and other parameters, the wind knife needs to be adjusted to change the angle at which the air outlet blows toward the film so that different films can stick to the surface of the roller. The adjustment process of the wind knife is complicated and time-consuming. Summary of the invention
[0003] In order to solve the above technical problems, the purpose of the present application is to provide an air knife adjustment device for an extrusion die head.
[0004] To achieve the above-mentioned purpose, the present application adopts the following technical scheme: an air knife adjustment device for an extrusion die head, wherein the extrusion die head is hoisted on a mold frame, and an air knife is installed on the rear side of the extrusion die head, and the air knife is provided with an air outlet for the flow of air to be output outward, and the air knife is movably installed on the mold frame to move the air outlet closer to and away from the extrusion port of the extrusion die head, and the air knife adjustment device is transmission-connected between the air knife and the mold frame, and the air knife adjustment device comprises:
[0005] A translation adjustment mechanism, comprising a translation guide rail extending along the front-rear direction and a hanging bracket slidably matched with the translation guide rail to move along the front-rear direction, wherein the translation guide rail is mounted on the mold frame;
[0006] A lifting and lowering adjustment mechanism, comprising a lifting guide rail extending in an up-down direction, a lifting bracket slidably matched with the lifting guide rail to move in the up-down direction, and a first driving assembly for driving the lifting bracket to move along the lifting guide rail, wherein the lifting guide rail is mounted on the hanging bracket, and the first driving assembly is drivingly connected between the hanging bracket and the lifting bracket; and
[0007] The angle adjustment mechanism includes a guide column extending in the left and right directions and a second drive assembly installed on the lifting bracket. The wind knife is rotatably arranged on the lifting bracket through the guide column. The second drive assembly is transmission-connected to the wind knife. The second drive assembly is used to drive the air outlet to swing along an arc path around the axis of the guide column.
[0008] In the above technical solution, it is further preferred that the translation adjustment mechanism also includes a locking assembly, which includes a locking threaded sleeve installed on the lifting bracket, a locking screw inserted in the locking threaded sleeve, and a brake block located between the locking screw and the translation guide rail, the locking screw is threadedly connected to the locking threaded sleeve, the brake block is connected to an end of the locking screw close to the translation guide rail, and the locking screw is configured to drive the brake block to approach and move away from the translation guide rail when rotating around its own axis.
[0009] In the above technical solution, it is further preferred that the ends of the translation guide rail and the lifting guide rail are both provided with limit blocks.
[0010] In the above technical solution, it is further preferred that a sliding block which slidably cooperates with the translation guide rail is installed on the lifting bracket.
[0011] In the above technical solution, it is further preferred that a slider which slidably cooperates with the lifting guide rail is installed on the lifting bracket.
[0012] In the above technical scheme, it is further preferred that the first driving component includes a lifting screw seat, a threaded slider, a lifting screw and a lifting handwheel, the lifting screw seat is installed on the lifting bracket, the threaded slider is installed on the lifting bracket, the lifting screw is simultaneously passed through the lifting screw seat and the threaded slider, and is threadedly connected to the lifting screw seat and the threaded slider, the lifting handwheel is connected to one end of the lifting screw to drive the lifting screw to rotate around its own axis, the threaded slider is configured to move back and forth along the lifting screw when the lifting screw rotates around its own axis, and the lifting screw extends in the up and down directions.
[0013] In the above technical solution, it is further preferred that the lifting and adjusting mechanism also includes a lifting and displaying assembly, the lifting and displaying assembly includes a ruler arranged on the lifting bracket and a lifting pointer arranged on the lifting bracket, the surface of the ruler is marked with scale lines for measuring distance, and the lifting pointer points to the scale lines on the surface of the ruler.
[0014] In the above technical solution, it is further preferred that the second driving component includes a rotating top shaft extending in the left-right direction and inserted on the lifting bracket, a pulling screw rod vertically passing through the rotating top shaft and a rotating nut sleeve mounted on the pulling screw rod, the rotating nut sleeve is threadedly connected to the pulling screw rod, one end of the pulling screw rod is connected to the wind knife transmission, and the rotating nut sleeve and one end of the pulling screw rod are relatively arranged on the upper and lower sides of the rotating top shaft.
[0015] In the above technical solution, it is further preferred that the surface of the rotating nut sleeve has a plurality of protrusions protruding radially outward, and the plurality of protrusions are distributed at equal angles along the circumference of the rotating nut sleeve.
[0016] In the above technical solution, it is further preferred that the angle adjustment mechanism also includes an angle display component, the angle display component includes an angle ruler arranged on the lifting bracket and an angle pointer arranged on the wind knife, the surface of the angle ruler is marked with scale lines for measuring angles, and the angle pointer points to the scale lines on the surface of the angle ruler.
[0017] Compared with the prior art, the present invention has the following beneficial effects:
[0018] The wind knife adjustment device of the present application has a simple structure and is easy to operate. The wind knife can quickly move away from and close to the extrusion die through a translation adjustment mechanism, which is convenient for cleaning the extrusion die and the roller, saving cleaning time to improve production efficiency; the lifting adjustment mechanism and the angle adjustment mechanism can quickly and accurately adjust the position of the air outlet at the extrusion die and the roller and the blowing angle, thereby improving the convenience and accuracy of the adjustment and allowing the film extruded by the extrusion die to better fit the roller. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 A schematic diagram of a three-dimensional structure of an air knife adjustment device provided in an embodiment of the present application installed on a mold frame;
[0020] Figure 2 for Figure 1 A side view of the device in FIG.
[0021] Figure 3 for Figure 2 A local enlarged schematic diagram of the middle A;
[0022] Figure 4 for Figure 1 A schematic diagram of the three-dimensional structure of the air knife adjustment device;
[0023] Figure 5 for Figure 4 A partial enlarged schematic diagram of point B in the middle;
[0024] Figure 6 for Figure 4 A side view of the air knife adjustment device in FIG.
[0025] Figure 7 for Figure 4 Rear view of the air knife adjustment device in.
[0026] Among them: 10, extrusion die head; 2, extrusion outlet; 20, mold frame; 3, crossbeam; 30, air knife; 1, air outlet; 40, air knife adjustment device; 4, translation adjustment mechanism; 41, translation guide rail; 411, limit block; 42, lifting bracket; 43, slider; 44, locking assembly; 441, locking thread sleeve; 442, locking screw; 443, brake block; 5, lifting adjustment mechanism; 51, lifting guide rail; 511, limit block; 52, lifting support Frame; 53, first drive assembly; 531, lifting screw seat; 532, threaded slider; 533, lifting screw; 534, lifting handwheel; 55, lifting display assembly; 551, ruler; 552, lifting pointer; 6, angle adjustment mechanism; 61, guide column; 62, second drive assembly; 621, rotating top shaft; 622, pulling screw; 623, rotating nut sleeve; 63, angle display assembly; 631, angle ruler; 632, angle pointer. DETAILED DESCRIPTION
[0027] To describe the technical content, structural features, achieved purpose and effect of the application in detail, the technical solutions in the embodiments of the application will be described below in conjunction with the drawings in the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all of the embodiments. In the following description, for the purpose of explanation, many specific details are set forth to provide a detailed description of various exemplary embodiments or implementations of the invention. However, various exemplary embodiments may also be implemented without these specific details or in the case of one or more equivalent arrangements. In addition, various exemplary embodiments may be different, but not necessarily exclusive. For example, without departing from the inventive concept, the specific shape, structure and characteristics of the exemplary embodiment may be used or implemented in another exemplary embodiment.
[0028] In the following, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.
[0029] The terms “front”, “rear”, “left”, “right”, “up” and “down” in this application refer to the attached Figure 1Front, back, left, right, up and down as shown.
[0030] In the present application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium.
[0031] An embodiment of the present application provides a wind knife adjustment device for an extrusion die. Usually, the raw materials of the film are conveyed to the extrusion die in a molten state after being fully plasticized and melted by the extruder, and are output to a roller in a film shape through the extrusion port of the extrusion die for subsequent shaping. A wind knife is arranged near the extrusion die. The wind knife is provided with a narrow and long air outlet, which is close to the extrusion port and blows flowing air toward the extrusion port to blow the film extruded from the extrusion port toward the roller, so that the film can be tightly attached to the roller.
[0032] like Figure 1 As shown, the extrusion die head 10 is suspended on a die frame 20 and supported on the ground by the die frame 20. The air knife 30 is installed on the rear side of the extrusion die head 10 and approaches the extrusion die head 10 from the back to the front. The air knife 30 is movably installed on the die frame 20 through the air knife adjustment device 40, and the air knife adjustment device 40 is used to realize movement in the front-to-back direction and the up-and-down direction, and at the same time, the angle of the air outlet 1 relative to the extrusion outlet 2 is adjusted.
[0033] The mold frame 20 includes a cross beam 3 extending in the front-rear direction, and the wind knife adjustment device 40 is installed on the cross beam 3 so as to drive the wind knife 30 to move in the front-rear direction.
[0034] like Figure 1 , 2 As shown, the wind knife adjustment device 40 includes a translation adjustment mechanism 4, a lifting adjustment mechanism 5 and an angle adjustment mechanism 6. The translation adjustment mechanism 4 is used to control the movement of the wind knife 30 in the front and rear directions, the lifting adjustment mechanism 5 is used to control the movement of the wind knife 30 in the up and down directions, and the angle adjustment mechanism 6 is used to adjust the angle of the air outlet 1 relative to the extrusion outlet 2.
[0035] like Figure 1-3As shown, the translation adjustment mechanism 4 includes a translation guide rail 41 extending in the front-to-back direction and a hanging bracket 42 hung on the lower side of the translation guide rail 41, and the translation guide rail 41 is installed on the crossbeam 3 of the mold frame 20; a slider 43 slidingly matched with the translation guide rail 41 is installed on the top of the hanging bracket 42, and the hanging bracket 42 can move back and forth in the front-to-back direction relative to the mold frame 20 through the sliding cooperation between the slider 43 and the translation guide rail 41. The translation adjustment mechanism 4 also includes a locking assembly 44, which is used to lock the lifting bracket 42 on the beam 3 to prevent the lifting bracket 42 from moving forward and backward; the locking assembly 44 includes a locking threaded sleeve 441 installed on the lifting bracket 42, a locking screw 442 inserted from bottom to top in the locking threaded sleeve 441, and a brake block 443 located between the locking screw 442 and the translation guide rail 41, the locking screw 442 is threadedly connected to the locking threaded sleeve 441, and the brake block 443 is connected to the upper end of the locking screw 442. The locking screw 442 rotates around its own axis under external operation and moves back and forth along the extension direction of its own axis, thereby driving the brake block 443 to approach and move away from the translation guide rail 41. When it is necessary to push the hanging bracket 42 to move forward and backward, the locking screw 442 is screwed so that the locking screw 442 drives the brake block 443 to move downward to move away from the translation guide rail 41. When the hanging bracket 42 has finished moving, the locking screw 442 is tightened upward so that the brake block 443 is pressed against the translation guide rail 41, thereby stopping the hanging bracket 42 from moving forward and backward, ensuring the stability of the wind knife 30 during lifting and angle adjustment. Limiting blocks 411 are also provided at both ends of the translation guide rail 41 to prevent the hanging bracket 42 from falling off the translation guide rail 41, thereby improving safety and stability.
[0036] like Figure 4 , 6As shown, the lifting and adjusting mechanism 5 includes a lifting guide rail 51 extending in the up-down direction, a lifting bracket 52 slidingly cooperated with the lifting guide rail 51 to move in the up-down direction, and a first driving component 53 for driving the lifting bracket 52 to move along the lifting guide rail 51. The lifting guide rail 51 is fixedly mounted on the hanging bracket 42, and a slider slidingly cooperated with the lifting guide rail 51 is mounted on the lifting bracket 52. The lifting bracket 52 can move back and forth in the up-down direction relative to the hanging bracket 42 through the sliding cooperation between the slider and the lifting guide rail 51. The first driving assembly 53 is connected between the hanging bracket 42 and the lifting bracket 52, and is used to drive the lifting bracket 52 to move up and down along the lifting guide rail 51; the first driving assembly 53 includes a lifting screw seat 531, a threaded slider 532, a lifting screw 533 and a lifting handwheel 534, the lifting screw seat 531 is fixedly mounted on the hanging bracket 42, the threaded slider 532 is fixedly mounted on the lifting bracket 52, the lifting screw 533 is simultaneously inserted into the lifting screw seat 531 and the threaded slider 532, and is threadedly connected with the lifting screw seat 531 and the threaded slider 532, and the lifting screw 533 extends in the up and down direction; the lifting handwheel 534 is connected to one end of the lifting screw 533 so as to be able to drive the lifting screw 533 to rotate around its own axis under external operation. The working principle of the first driving assembly 53 is: when the lifting screw 533 rotates around its own axis under the drive of the lifting handwheel 534, the threaded slider 532 drives the lifting bracket 52 to move up and down along the lifting screw 533. The threaded slider 532 cooperates with the lifting screw 533 to drive the lifting bracket 52 to move in the up and down directions; the slider 54 cooperates with the lifting guide rail 51 to guide the movement of the lifting bracket 52. The lifting adjustment mechanism 5 also has a self-locking function. After the lifting bracket 52 moves to the corresponding position, the lifting bracket 52 is locked in the position to ensure the stability of the wind knife 30 during translation and angle adjustment.
[0037] Limiting blocks 511 are also provided at both ends of the lifting guide rail 51 to prevent the lifting bracket 52 from falling off the lifting guide rail 51, thereby improving safety and stability.
[0038] like Figure 7 As shown, in order to improve the accuracy of the lifting distance of the wind knife 30, the lifting adjustment mechanism 5 also includes a lifting display component 55, and the lifting display component 55 includes a ruler 551 installed at the rear end of the lifting bracket 42 and a lifting pointer 552 installed at the rear end of the lifting bracket 52. The ruler 551 extends in the up and down directions, and the surface is marked with scale lines for measuring distance, and the lifting pointer 552 points to the scale lines on the surface of the ruler 551; when the lifting bracket 52 is lifted and lowered, the lifting pointer 552 moves in the up and down directions with the lifting bracket 52, and points to different scale lines on the ruler 551, so that the operator can intuitively see the moving distance of the lifting bracket 52 through the scale lines pointed to by the lifting pointer 552.
[0039] like Figure 4-6 As shown, the angle adjustment mechanism 6 includes a guide column 61 extending in the left-right direction and a second drive assembly 62 installed on the lifting bracket 52. The guide column 61 is inserted into a pair of left and right oppositely arranged side panels of the lifting bracket 52, and the wind knife 30 is rotatably set on the lifting bracket 52 through the guide column 61.
[0040] The second driving assembly 62 is connected to the wind knife 30 for driving the tuyere 1 to rotate around the axis X of the guide column 61. 1 It swings along an arc path, thereby realizing the angle adjustment of the air outlet 1 relative to the extrusion outlet 2. The second driving assembly 62 includes a rotating top shaft 621 extending in the left-right direction, a pulling screw 622 vertically passing through the rotating top shaft 621, and a rotating nut sleeve 623 sleeved on the pulling screw 622. The rotating top shaft 621 extends in the left-right direction and is inserted into a pair of left and right oppositely arranged side plates of the lifting bracket 52 to support the pulling screw 622 and the rotating nut sleeve 623 on the lifting bracket 52. A through hole is provided on the rotating top shaft 621 for the pulling screw 622 to pass through. The diameter of the rotating nut sleeve 623 is larger than the diameter of the through hole. The rotating nut sleeve 623 is arranged on the upper side of the rotating top shaft 621 and is threadedly connected to the pulling screw 622. The surface of the rotating nut sleeve 623 has a plurality of protrusions protruding radially outward, and the plurality of protrusions are distributed at equal angles along the circumference of the rotating nut sleeve 623, so as to facilitate the operator to operate the rotating nut sleeve 623. The lower end of the pulling screw 622 is located on the lower side of the rotating top shaft 621 and is transmission-connected to the wind knife 30.
[0041] When the rotating nut sleeve 623 rotates, the screw rod 622 is pulled to drive the wind knife 30 to move in the up and down directions relative to the rotating nut sleeve 623 and the rotating top shaft 621 .
[0042] In the embodiment of the present application, the air outlet 1 is located at the front end of the wind knife 30, the guide column 61 is hinged to the front half of the wind knife 30, and the pull screw 622 is hinged to the rear half of the wind knife 30. When the pull screw 622 moves up and down under the operation of the rotating nut sleeve 623, the rear half of the wind knife 30 swings up and down, so that the wind knife 30 as a whole rotates around the axis X 1 Swing back and forth, the tuyere 1 is along the axis X 1 Adjust the angle of rotation to the center of the circle.
[0043] In order to improve the accuracy of the rotation angle of the tuyere 1, the angle adjustment mechanism 6 also includes an angle display assembly 63, which includes an angle scale 631 and an angle pointer 632. The angle scale 631 is arranged on the outside of at least one side plate of the lifting bracket 52, and the angle pointer 632 is installed at the end of the wind knife 30 corresponding to the angle scale 631. The angle scale 631 extends along an arc direction, which is concentric with the arc path of the movement of the tuyere 1. The surface of the angle scale 631 is marked with scale lines for measuring angles, and the angle pointer 632 points to the scale lines on the surface of the angle scale; when the tuyere 1 rotates, the angle pointer 632 rotates along an arc path with the wind knife 30 and points to different scale lines on the angle scale 631, so that the operator can intuitively see the rotation angle of the tuyere 1 through the scale lines pointed by the angle pointer 632, and make timely adjustments to the tuyere 1, thereby improving the accuracy and convenience of angle adjustment.
[0044] The wind knife adjustment device of the present application has a simple structure and is easy to operate. The wind knife 30 can quickly move away from and approach the extrusion die 10 through the translation adjustment mechanism 4, which is convenient for cleaning the extrusion die 10 and the roller, saving cleaning time to improve production efficiency; the lifting adjustment mechanism 5 and the angle adjustment mechanism 6 can quickly and accurately adjust the position of the air outlet 1 at the extrusion die and the roller and the blowing angle, thereby improving the convenience and accuracy of the adjustment and allowing the film extruded by the extrusion die to better fit the roller.
[0045] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present application. Without departing from the spirit and scope of the present application, the present application may have various changes and improvements, and the scope of protection required by the present application is defined by the attached claims, description and their equivalents.
Claims
1. A wind knife adjustment device for an extrusion die head, wherein the extrusion die head is hoisted on a die frame, and a wind knife is installed on the rear side of the extrusion die head, and the wind knife is provided with an air outlet for the flow of air to be output outward, and the wind knife is movably installed on the die frame to move the air outlet close to and away from the extrusion port of the extrusion die head, characterized in that: The wind knife adjusting device is transmission-connected between the wind knife and the mold frame, and the wind knife adjusting device comprises: A translation adjustment mechanism, comprising a translation guide rail extending in the front-rear direction and a hanging bracket slidably matched with the translation guide rail to move in the front-rear direction, wherein the translation guide rail is mounted on the mold frame; A lifting and lowering adjustment mechanism, comprising a lifting guide rail extending in an up-down direction, a lifting bracket slidably matched with the lifting guide rail to move in the up-down direction, and a first driving assembly for driving the lifting bracket to move along the lifting guide rail, wherein the lifting guide rail is mounted on the hanging bracket, and the first driving assembly is drivingly connected between the hanging bracket and the lifting bracket; and The angle adjustment mechanism includes a guide column extending in the left and right directions and a second drive assembly installed on the lifting bracket. The wind knife is rotatably arranged on the lifting bracket through the guide column. The second drive assembly is transmission-connected to the wind knife. The second drive assembly is used to drive the air outlet to swing along an arc path around the axis of the guide column.
2. The wind knife adjustment device according to claim 1, characterized in that: The translation adjustment mechanism also includes a locking assembly, which includes a locking threaded sleeve installed on the lifting bracket, a locking screw inserted in the locking threaded sleeve, and a brake block located between the locking screw and the translation guide rail. The locking screw is threadedly connected to the locking threaded sleeve, and the brake block is connected to an end of the locking screw close to the translation guide rail. The locking screw is configured to drive the brake block to approach and move away from the translation guide rail when rotating around its own axis.
3. The wind knife adjustment device according to claim 1, characterized in that: The ends of the translation guide rail and the lifting guide rail are both provided with limit blocks.
4. The wind knife adjustment device according to claim 1, characterized in that: The hanging bracket is provided with a sliding block which is slidably matched with the translation guide rail.
5. The wind knife adjustment device according to claim 1, characterized in that: The lifting bracket is provided with a sliding block which is slidably matched with the lifting guide rail.
6. The wind knife adjustment device according to claim 1, characterized in that: The first driving component includes a lifting screw seat, a threaded slider, a lifting screw and a lifting handwheel. The lifting screw seat is installed on the lifting bracket, and the threaded slider is installed on the lifting bracket. The lifting screw is simultaneously inserted into the lifting screw seat and the threaded slider, and is threadedly connected to the lifting screw seat and the threaded slider. The lifting handwheel is connected to one end of the lifting screw to drive the lifting screw to rotate around its own axis. The threaded slider is configured to move back and forth along the lifting screw when the lifting screw rotates around its own axis, and the lifting screw extends in the up and down directions.
7. The wind knife adjustment device according to claim 1, characterized in that: The lifting and lowering adjustment mechanism also includes a lifting and lowering display component, which includes a ruler arranged on the lifting bracket and a lifting pointer arranged on the lifting bracket. The surface of the ruler is marked with scale lines for measuring distance, and the lifting pointer points to the scale lines on the surface of the ruler.
8. The wind knife adjustment device according to claim 1, characterized in that: The second driving component includes a rotating top shaft extending in the left-right direction and inserted on the lifting bracket, a pulling screw rod vertically passing through the rotating top shaft and a rotating nut sleeve mounted on the pulling screw rod, the rotating nut sleeve is threadedly connected to the pulling screw rod, one end of the pulling screw rod is transmission connected to the wind knife, and the rotating nut sleeve and one end of the pulling screw rod are relatively arranged on the upper and lower sides of the rotating top shaft.
9. The wind knife adjustment device according to claim 8, characterized in that: The surface of the rotating nut sleeve is provided with a plurality of protrusions protruding radially outward, and the plurality of protrusions are distributed at equal angles along the circumference of the rotating nut sleeve.
10. The wind knife adjustment device according to claim 1, characterized in that: The angle adjustment mechanism also includes an angle display component, which includes an angle ruler arranged on the lifting bracket and an angle pointer arranged on the wind knife. The surface of the angle ruler is marked with scale lines for measuring angles, and the angle pointer points to the scale lines on the surface of the angle ruler.