A silver bright steel rod ovality detection device

Abstract

The present application relates to silver bright steel processing technical field, especially a kind of silver bright steel bar ovality detection equipment, the upper end of chassis is equipped with the roller type hoop mechanism for fixing silver bright steel bar, the output end of speed reducer is equipped with friction driving wheel mechanism, friction driving wheel mechanism is sleeved with the belt for driving silver bright steel bar rotation, movable frame is equipped with fixed rod, two rotating plates are rotatably arranged on the fixed rod, and support rod is fixedly connected on each rotating plate.The present application moves downward by movable frame, the belt is lifted up by the reaction force of steel bar, the tension of belt makes two support rods rotate downward around fixed rod, the contact area of belt and steel bar gradually increases, different diameter steel bar can be self-adapting wrapped, and support rod is extruded first spring after rotating downward, the elastic force of compressed first spring is released after detection, belt is automatically tightened, to prevent belt from loosening and separating.

Description

Technical Field

[0001] This invention relates to the field of bright steel processing technology, and in particular to a device for detecting the ellipticity of bright steel bars. Background Technology

[0002] After the bright steel bar is peeled, it needs to be tested for ellipticity to ensure that the outer diameter defects of the pipes and bars to be processed are controlled within a reasonable processing requirement. During the ellipticity test, the bright steel bar is first limited, then the 100% testing end is brought into contact with the surface of the steel bar, and finally the bright steel bar is rotated. The radial runout caused by its ellipticity is transmitted to the dial indicator to complete the ellipticity test. When rotating the bright steel bar, in order to avoid the test error introduced by uneven rotation speed, the steel bar is generally driven to rotate by a fixed belt mechanism. Since the diameter specifications of bright steel bars vary, the fixed belt mechanism cannot be adaptively adjusted and is difficult to match steel bars of different diameters. Moreover, during the shutdown and reset process, the belt is prone to loosening or even falling off the drive wheel due to loss of tension, which seriously affects the stability of continuous operation of the equipment. Summary of the Invention

[0003] The purpose of this invention is to solve the shortcomings of existing technologies, such as the inability of fixed belt mechanisms to self-adjust, difficulty in matching steel bars of different diameters, and the tendency of the belt to fall off due to loss of tension during the shutdown and reset process. Therefore, this invention proposes a device for detecting the ellipticity of bright steel bars.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: Design a device for detecting the ellipticity of bright steel bars, including a base frame. A first mounting frame is detachably connected to one side of the base frame. A movable frame is slidably connected to the first mounting frame. The upper end of the base frame is provided with a roller-type clamping mechanism for fixing the bright steel bars. A reduction motor is mounted on the movable frame. A friction wheel mechanism is provided on the output end of the reduction motor. A belt for driving the bright steel bars to rotate is sleeved on the friction wheel mechanism. A fixed rod is provided on the movable frame. Two rotating plates are rotatably mounted on the fixed rod. A support rod is fixedly connected to each rotating plate. A first spring is provided on each rotating plate. One end of each first spring is fixedly connected to the movable frame.

[0005] Preferably, the roller clamping mechanism includes two symmetrically arranged second mounting brackets, both of which are fixedly connected to the upper end of the base frame. Each second mounting bracket has support wheels on both sides of its upper end for supporting the bright steel bar. Each second mounting bracket has a top plate detachably connected to its upper end by bolt fasteners. Each top plate has pressure rollers on both sides of its bottom end, and each pressure roller is in contact with the upper end of the bright steel bar.

[0006] Preferably, the friction drive wheel mechanism includes a drive wheel, which is fixedly connected to the output end of the geared motor. The drive wheel is provided with two parallel first limiting rings, and the belt is located between the two first limiting rings.

[0007] Preferably, the outer wall of the drive wheel is provided with a plurality of grooves at equal intervals along the axis, each groove is slidably connected with a protrusion, the top of each protrusion can contact the belt, the bottom of each protrusion is connected to the bottom of the groove through a third spring, the bottom of each protrusion is fixedly connected with a pressure rod, the bottom of each groove is provided with a pressure sensor, and the bottom of each pressure rod is in contact with the corresponding pressure sensor.

[0008] Preferably, the protrusion and the pressure rod are an integral structure.

[0009] Preferably, it further includes a span scaling mechanism, which includes a fixed plate fixedly connected to a movable frame. Two connecting shafts are symmetrically rotatably mounted on the fixed plate. A gear is fixedly connected to each connecting shaft, and a fixed seat is detachably connected to each gear. A push rod is provided at the bottom end of each fixed seat, and each push rod is located outside the corresponding support rod. A second movable plate is slidably inserted into the upper end of the movable frame. A double-sided toothed plate is fixedly connected to the bottom end of the second movable plate, with different gears meshing on both sides of the double-sided toothed plate. A connecting plate is mounted on the upper end of the second movable plate, and a telescopic cylinder for driving the connecting plate to move vertically is provided at the upper end of the movable frame.

[0010] Preferably, each of the support rods is fixedly connected to two parallel second limiting rings, and each of the push rods is located between the corresponding two second limiting rings.

[0011] Preferably, it further includes a lateral floating suppression mechanism, which includes a rotating tube, a slot on the support rod, and the rotating tube is rotatably connected to the support rod, with the rotating tube cooperating with the slot.

[0012] Preferably, the upper end of the support rod is fixedly connected to limit plates on both sides of the rotating tube. A sliding groove is provided on the opposite side of the two limit plates. A track is provided in each sliding groove. A slider is slidably connected on each track. A rotating rod is rotatably connected between the two sliders. The rotating rod is in contact with the upper surface of the belt.

[0013] Preferably, the rotating rod is a stainless steel rod.

[0014] The ellipticity testing device for bright silver steel bars proposed in this invention has the following advantages: As the movable frame moves downward, the belt is pushed upward by the reaction force of the steel bar. The tension of the belt causes the two support rods to rotate downward around the fixed rod, gradually increasing the contact area between the belt and the steel bar. This allows for adaptive wrapping of steel bars of different diameters. After the support rods rotate downward, they compress the first spring. After the test is completed, the compressed first spring releases the accumulated elasticity, automatically tightening the belt and preventing it from slipping off due to slack. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of a device for detecting the ellipticity of bright steel bars proposed in this invention. Figure 1 ; Figure 2 This is a schematic diagram of the structure of a device for detecting the ellipticity of bright steel bars proposed in this invention. Figure 2 ; Figure 3 This is a schematic diagram of the connection between the base frame and the roller clamping mechanism in the ellipticity testing equipment for bright silver steel bars proposed in this invention; Figure 4 This is a schematic diagram of the connection between the first mounting frame and the movable frame in the ellipticity testing device for bright silver steel bars proposed in this invention; Figure 5 This is a schematic diagram of the connection between the movable frame and the fixed rod in the ellipticity testing device for bright silver steel bars proposed in this invention; Figure 6 This is a schematic diagram of the connection between the friction wheel mechanism and the belt in the ellipticity detection device for bright silver steel bars proposed in this invention; Figure 7 for Figure 6 A magnified view of the structure at point A above; Figure 8 This is a schematic diagram of the connection between the movable frame and the support span scaling mechanism in the ellipticity detection device for bright silver steel bars proposed in this invention; Figure 9 This is a schematic diagram of the supporting span scaling mechanism in the ellipticity detection device for bright silver steel bars proposed in this invention; Figure 10 This is a schematic diagram of the connection between the support rod and the lateral floating suppression mechanism in the ellipticity detection device for bright silver steel bars proposed in this invention.

[0016] In the diagram: 1. Base frame; 2. Ellipticity measuring component; 3. First mounting bracket; 4. Movable frame; 5. Lifting cylinder; 6. Roller clamping mechanism; 7. Gear motor; 8. Friction wheel mechanism; 9. Belt; 10. Fixed rod; 11. Rotating plate; 12. Support rod; 13. First spring; 14. Support span scaling mechanism; 15. Lateral floating suppression mechanism; 21. Groove frame; 22. First movable plate; 23. Dial gauge; 24. Second spring; 25. Bolt adjusting component; 61. Second mounting bracket; 62. Support wheel; 63. Top plate; 64. Bolt fixing component; 65. Pressure roller; 81. Drive wheel; 82. First limiting ring; 83. Groove; 84. Third spring; 85. Protrusion; 86. Pressure rod; 87. Pressure sensor; 141. Fixing plate; 142. Connecting shaft; 143. Gear; 144. Fixing seat; 145. Push rod; 146. Second movable plate; 147. Double-sided toothed plate; 148. Connecting plate; 149. Telescopic cylinder; 1410. Second limiting ring; 151. Groove; 152. Rotating tube; 153. Limiting plate; 154. Slide groove; 155. Track; 156. Slider; 157. Rotating rod. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0018] Example 1: Refer to Figure 1-7 An ellipticity testing device for bright steel bars includes a base frame 1. An ellipticity testing component 2 for ellipticity testing is provided at the upper end of the base frame 1. A first mounting frame 3 is detachably connected to one side of the base frame 1. A movable frame 4 is slidably connected to the first mounting frame 3. A lifting cylinder 5 for driving the movable frame 4 to move vertically is provided on the first mounting frame 3. A roller-type clamping mechanism 6 for fixing the bright steel bars is provided at the upper end of the base frame 1. A reduction motor 7 is installed on the movable frame 4. A friction wheel mechanism 8 is provided at the output end of the reduction motor 7. A belt 9 for driving the bright steel bars to rotate is sleeved on the friction wheel mechanism 8. A fixed rod 10 is provided on the movable frame 4. Two rotating plates 11 are rotatably provided on the fixed rod 10. A support rod 12 is fixedly connected to each rotating plate 11. The lower surface of the belt 9 is in contact with each support rod 12. A first spring 13 is provided on each rotating plate 11. One end of each first spring 13 is fixedly connected to the movable frame 4. Reference Figure 2The ellipticity testing component 2 includes a groove frame 21, which is fixedly connected to the upper end of the base frame 1. A first movable plate 22 is slidably connected to the groove frame 21. A dial indicator 23 for testing is provided on the first movable plate 22. The lower surface of the first movable plate 22 is connected to the groove frame 21 through a second spring 24. A bolt adjusting component 25 is inserted into the first movable plate 22. A threaded hole is opened on the groove frame 21, and the bolt adjusting component 25 cooperates with the threaded hole. Reference Figure 3 The roller clamping mechanism 6 includes two symmetrically arranged second mounting brackets 61. Both symmetrically arranged second mounting brackets 61 are fixedly connected to the upper end of the base frame 1. Each second mounting bracket 61 has support wheels 62 on both sides of its upper end for supporting the bright steel bar. Each second mounting bracket 61 has a top plate 63 detachably connected to its upper end by bolt fasteners 64. Each top plate 63 has pressure rollers 65 on both sides of its bottom end. Each pressure roller 65 is in contact with the upper end of the bright steel bar. Reference Figure 7 The friction drive wheel mechanism 8 includes a drive wheel 81, which is fixedly connected to the output end of the reduction motor 7. The drive wheel 81 is provided with two parallel first limiting rings 82, and the belt 9 is located between the two first limiting rings 82. The outer wall of the drive wheel 81 is provided with a number of grooves 83 at equal intervals along the axis. Each groove 83 is slidably connected with a protrusion 85. The top of each protrusion 85 can contact the belt 9. The bottom of each protrusion 85 is connected to the bottom of the groove 83 through a third spring 84. The bottom of each protrusion 85 is fixedly connected with a pressure rod 86. The protrusion 85 and the pressure rod 86 are an integral structure. The bottom of each groove 83 is provided with a pressure sensor 87, and the bottom of each pressure rod 86 is in contact with the corresponding pressure sensor 87.

[0019] Working principle: The bright silver steel bar to be tested is placed on several support wheels 62, and then the top plate 63 is fixed to the upper end of the second mounting frame 61 by bolt fasteners 64, so that the pressure roller 65 at the bottom of the top plate 63 abuts and presses against the upper end of the steel bar. The pressure roller 65 and the support wheels 62 form a four-point limiting support to radially constrain the steel bar, avoid radial runout caused by excessive torque during the test, and improve the test accuracy. Before testing, rotate the bolt adjusting component 25 to move it downward under the guidance of the threaded hole. The downward movement of the bolt adjusting component 25 pushes the first movable plate 22 to move downward along the groove frame 21. After the first movable plate 22 moves downward, it squeezes the second spring 24. The second spring 24 generates elastic force after being compressed. At the same time, the first movable plate 22 also drives the dial indicator 23 to move downward, so that the testing end of the dial indicator 23 contacts the surface of the steel bar, ensuring that the testing end of the dial indicator 23 is in contact with the steel bar, thereby reducing testing errors. Initially, one side of the belt 9 is fitted onto the drive wheel 81, and the other side of the belt 9 is fitted onto two support rods 12. The distance between the two support rods 12 is much larger than the diameter of the steel bar. After the lifting cylinder 5 is started, it drives the movable frame 4 to move downward. The movable frame 4 drives the reduction motor 7 and the fixed rod 10 to move downward synchronously. After moving downward for a certain distance, the belt 9 contacts the surface of the steel bar. The movable frame 4 continues to move downward, and the belt 9 is pushed upward by the reaction force of the steel bar, thereby pushing the protrusion 85 to compress the third spring 84. At the same time, the pressure rod 86 triggers the pressure sensor 87. When the value detected by the pressure sensor 87 reaches the preset threshold, the lifting cylinder 5 stops moving. At the same time, the tension of the belt 9 acts on the two support rods 12, causing the two support rods 12 to rotate downwards around the fixed rod 10, so that the contact area between the belt 9 and the steel bar gradually increases, which can adaptively wrap the steel bars of different diameters. After the support rods 12 rotate downwards, they compress the first spring 13. The first spring 13 generates elastic force after being compressed. The elastic force generated by the first spring 13 compresses the belt 9 through the support rods 12, so that the belt 9 is gradually tightened, preventing the belt 9 from loosening during operation. After the geared motor 7 starts, it drives the drive wheel 81 to rotate. The drive wheel 81 drives the steel bar to rotate at a constant speed through the belt 9, so as to avoid errors caused by uneven rotation speed of the steel bar. During the rotation of the steel bar, the radial runout caused by its ellipticity is transmitted to the dial indicator 23. The dial indicator 23 collects displacement data in real time. After the test is completed, the lifting cylinder 5 drives the movable frame 4 to move upward and reset. As the belt 9 gradually disengages from the steel bar, the compressed first spring 13 releases the stored elastic force, pulls the rotating plate 11 and the support rod 12 to swing outward and reset, automatically tightening the belt 9 to prevent the belt 9 from disengaging from the drive wheel 81 due to slack.

[0020] Example 2: During the downward movement of the movable frame 4, when the belt 9 contacts the steel bar, the tension of the belt 9 causes the two support rods 12 to rotate downwards towards each other. When the pressure value detected by one of the pressure sensors 87 reaches the set value, the lifting cylinder 5 stops driving the movable frame 4 downwards. At this time, the elastic force generated by the compression of the first spring 13 pushes the support rod 12 outwards, and the support rod 12 pushes the belt 9 outwards, resulting in a reduction in the contact area between the belt 9 and the steel bar. This makes it easier for the belt 9 to slip against the steel bar, thereby reducing the effect of the belt 9 driving the steel bar and affecting the detection of the steel bar. (Refer to...) Figure 8-9As another preferred embodiment of the present invention, the difference from embodiment 1 is that it further includes a support span scaling mechanism 14. The support span scaling mechanism 14 includes a fixed plate 141, which is fixedly connected to the movable frame 4. Two connecting shafts 142 are symmetrically rotatably provided on the fixed plate 141. A gear 143 is fixedly connected to each connecting shaft 142. A fixed seat 144 is detachably connected to each gear 143. A push rod 145 is provided at the bottom end of each fixed seat 144. Each push rod 145 is located outside the corresponding support rod 12. On the side, a second movable plate 146 is slidably inserted into the upper end of the movable frame 4. A double-sided toothed plate 147 is fixedly connected to the bottom end of the second movable plate 146. Different gears 143 mesh on both sides of the double-sided toothed plate 147. A connecting plate 148 is installed on the upper end of the second movable plate 146. A telescopic cylinder 149 is provided at the upper end of the movable frame 4 for driving the connecting plate 148 to move in the vertical direction. Two parallel second limiting rings 1410 are fixedly connected to each support rod 12. Each push rod 145 is located between the corresponding two second limiting rings 1410.

[0021] Working principle: When the pressure value detected by one of the pressure sensors 87 reaches the set value, the lifting cylinder 5 stops driving the movable frame 4 to move downward. At this time, the telescopic cylinder 149 drives the connecting plate 148 to move downward, the connecting plate 148 drives the second movable plate 146 to move downward, the second movable plate 146 drives the double-sided toothed plate 147 to move, and after the double-sided toothed plate 147 moves downward, it drives the two gears 143 to rotate. Each gear 143 drives the fixed seat 144 to rotate, and each fixed seat 144 drives the push rod 145 to rotate, so that the two push rods 145 rotate synchronously in opposite directions, pushing the support rod 12 to rotate downward. During the rotation of the two push rods 145 towards each other, they compress the corresponding two support rods 12. The compressed support rods 12 continue to compress the first spring 13 through the rotating plate 11. The first spring 13 contracts after being compressed, providing a range of motion for the rotation of the rotating plate 11. At this time, the elastic force generated by the compression of the first spring 13 acts on the push rods 145. After being compressed by the push rods 145, the support rods 12 gradually separate from the belt 9, so that the support rods 12 no longer push the belt 9 outward, thus not reducing the contact area between the belt 9 and the steel bar, and thus preventing slippage between the belt 9 and the steel bar, thereby improving the effect of the belt 9 driving the steel bar.

[0022] Example 3: When inspecting multiple steel bars sequentially, each time the belt 9 contacts and separates from the support rod 12, the contact position between the belt 9 and the support rod 12 changes. This causes the belt 9 to shift relative to the vertical plane after being tightened. During the rotation of the belt 9, it pulls the steel bars horizontally, thereby reducing the accuracy of the steel bar inspection. (Refer to...) Figure 9-10As another preferred embodiment of the present invention, the difference from embodiment 2 is that it also includes a lateral floating suppression mechanism 15. The lateral floating suppression mechanism 15 includes a rotating tube 152, a slot 151 is provided on the support rod 12, the rotating tube 152 is rotatably connected to the support rod 12, the rotating tube 152 cooperates with the slot 151, the upper end of the support rod 12 is fixedly connected to both sides of the rotating tube 152 with limit plates 153, and a sliding groove 154 is provided on the opposite side of the two limit plates 153. Each sliding groove 154 is provided with a track 155, and a slider 156 is slidably connected on each track 155. A rotating rod 157 is rotatably connected between the two sliders 156. The rotating rod 157 is a stainless steel rod and contacts the upper surface of the belt 9.

[0023] Working principle: During the rotation of the two push rods 145 towards each other, the two corresponding support rods 12 are squeezed. After the support rods 12 move, they drive the two limiting plates 153 to move. The two moving limiting plates 153 limit the side of the belt 9, ensuring that the contact position between the belt 9 and the rotating tube 152 remains unchanged each time. This prevents the belt 9 from shifting from the vertical plane after being tightened, thus preventing the steel bar from moving horizontally and improving the detection accuracy of the steel bar. In addition, the rotating tube 152 is rotatably connected to the support rods 12. After the belt 9 rotates, it rolls into contact with the rotating tube 152, reducing the friction on the belt 9. At the same time, the rotating rod 157 drives the slider 156 to move downward along the length of the track 155 under its own weight. The rotating rod 157 contacts the upper surface of the belt 9 and squeezes the belt 9 with its own weight, so as to prevent the side of the belt 9 from being dented at the contact point with the limiting plate 153, thereby improving the contact effect between the belt 9 and the steel rod.

[0024] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A silver bright steel bar ovality detection equipment, comprising a chassis (1), a first mounting frame (3) is detachably connected to one side of the chassis (1), and a movable frame (4) is slidably connected to the first mounting frame (3), characterized in that, in: The upper end of the base frame (1) is provided with a roller clamping mechanism (6) for fixing the silver bright steel bar. The movable frame (4) is equipped with a reduction motor (7). The output end of the reduction motor (7) is provided with a friction wheel mechanism (8). The friction wheel mechanism (8) is sleeved with a belt (9) for driving the silver bright steel bar to rotate. The movable frame (4) is provided with a fixed rod (10). Two rotating plates (11) are rotatably provided on the fixed rod (10). Each rotating plate (11) is fixedly connected with a support rod (12). Each rotating plate (11) is provided with a first spring (13). One end of each first spring (13) is fixedly connected to the movable frame (4).

2. The silver bright steel bar ovality detection apparatus according to claim 1, wherein The roller clamping mechanism (6) includes two symmetrically arranged second mounting brackets (61). Both symmetrically arranged second mounting brackets (61) are fixedly connected to the upper end of the base frame (1). Each second mounting bracket (61) has a support wheel (62) on both sides of its upper end for supporting the silver bright steel bar. Each second mounting bracket (61) has a top plate (63) detachably connected to its upper end by bolt fasteners (64). Each top plate (63) has a pressure wheel (65) on both sides of its bottom end. Each pressure wheel (65) is in contact with the upper end of the silver bright steel bar.

3. The silver bright steel bar ovality detection apparatus according to claim 1, wherein The friction drive wheel mechanism (8) includes a drive wheel (81), which is fixedly connected to the output end of the geared motor (7). The drive wheel (81) is provided with two parallel first limiting rings (82), and the belt (9) is located between the two first limiting rings (82).

4. The silver bright steel bar ovality detection apparatus according to claim 3, wherein The outer wall of the drive wheel (81) is provided with a plurality of grooves (83) at equal intervals along the axis. Each groove (83) is slidably connected with a protrusion (85). The top of each protrusion (85) can contact the belt (9). The bottom of each protrusion (85) is connected to the bottom of the groove (83) through a third spring (84). The bottom of each protrusion (85) is fixedly connected with a pressure rod (86). The bottom of each groove (83) is provided with a pressure sensor (87). The bottom of each pressure rod (86) is in contact with the corresponding pressure sensor (87).

5. The silver bright steel bar ovality detection apparatus according to claim 4, wherein The protrusion (85) and the pressure rod (86) are an integral structure.

6. The silver bright steel bar ovality detection apparatus according to claim 1, wherein It also includes a span scaling mechanism (14), which includes a fixed plate (141) fixedly connected to the movable frame (4). Two connecting shafts (142) are symmetrically rotatably mounted on the fixed plate (141). A gear (143) is fixedly connected to each connecting shaft (142). A fixed seat (144) is detachably connected to each gear (143). A push rod (145) is provided at the bottom end of each fixed seat (144). The push rods (145) are all located on the outside of the corresponding support rods (12). The upper end of the movable frame (4) is slidably connected to the second movable plate (146). The bottom end of the second movable plate (146) is fixedly connected to the double-sided toothed plate (147). Different gears (143) mesh on both sides of the double-sided toothed plate (147). The upper end of the second movable plate (146) is equipped with a connecting plate (148). The upper end of the movable frame (4) is provided with a telescopic cylinder (149) for driving the connecting plate (148) to move in the vertical direction.

7. The ellipticity testing equipment for bright silver steel bars according to claim 6, characterized in that, Each of the support rods (12) is fixedly connected to two parallel second limiting rings (1410), and each of the push rods (145) is located between the corresponding two second limiting rings (1410).

8. The ellipticity testing equipment for bright silver steel bars according to claim 7, characterized in that, It also includes a lateral floating suppression mechanism (15), which includes a rotating tube (152), and a slot (151) is provided on the support rod (12). The rotating tube (152) is rotatably connected to the support rod (12), and the rotating tube (152) cooperates with the slot (151).

9. The ellipticity testing equipment for bright silver steel bars according to claim 8, characterized in that, The upper end of the support rod (12) is fixedly connected to both sides of the rotating tube (152) with limiting plates (153). Each of the two limiting plates (153) has a groove (154) on its opposite side. Each groove (154) has a track (155) in it. Each track (155) has a slider (156) slidably connected to it. A rotating rod (157) is rotatably connected between the two sliders (156). The rotating rod (157) is in contact with the upper surface of the belt (9).

10. The ellipticity testing equipment for bright silver steel bars according to claim 9, characterized in that, The rotating rod (157) is a stainless steel rod.

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