Pressing column lifting device

Abstract

The invention discloses a pressing column lifting device which comprises a main body support, a main clamping piece connected with a pressing column, a lifting rope fixedly connected with the main clamping piece, a first pulley, a second pulley and a winch fixedly installed on the top face of the main body support, according to the pressing column lifting device, the winch is driven by electric power, the lifting rope is tightened, meanwhile, the main clamping piece is arranged at the end of the lifting rope to be connected with the pressing column, and therefore lifting of the pressing column is completed to be separated from the interior of the test cylinder; and the lifting rope sequentially bypasses the first pulley and the second pulley to change the overall tension direction, so that the overall device is more labor-saving, meanwhile, the requirement for operators is reduced through electric driving, the working efficiency is improved, and meanwhile, the safety risk is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of crushing index measuring instruments, in particular to a crushing column lifting device. Background Art

[0002] The crushing index measuring instrument is used in conjunction with a press to measure the crushing value of crushed stone and determine the strength of crushed stone. The crushing index measuring instrument consists of three parts: a test cylinder, a pressure column, and a bottom plate.

[0003] The pressure column is lifted manually before and after the test, and crushed stones are loaded or poured out. During the test, crushed stone chips and other fine particles are often stuck between the pressure column and the cylinder wall. In view of the weight of the pressure column and the clamping effect of the fine particles, it is more difficult to lift the pressure column, which is highly selective for operators, reduces the work efficiency of the operators, and increases the safety risks of manual operation. Therefore, we proposed a pressure column lifting device. Summary of the invention

[0004] The object of the present invention is to provide a pressure column lifting device to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a pressure column lifting device, comprising a main support, a main clamping piece connected to the pressure column, a lifting rope fixedly connected to the main clamping piece, a first pulley and a second pulley for bypassing the lifting rope, and a winch fixedly installed on the top surface of the main support, the end of the lifting rope away from the main clamping piece is also fixedly connected to the winch, and the main support is also provided with a movable component, and the movable component includes a sub-support fixedly connected to the main support, a slide rail slidably arranged on the sub-support, a first screw rod rotatably arranged on the sub-support, and a sliding The cam is connected with the second pulley by the second threaded rod, and the second threaded rod is connected with the second threaded rod by the second threaded rod; the auxiliary bracket is also provided with an adjusting component and a linkage component, and the adjusting component includes a movable head rotatably arranged on the auxiliary bracket, a fixed rod fixedly connected to the movable head, a sliding seat slidably arranged on the auxiliary bracket, a disc-shaped shaft rotatably arranged on the sliding seat, a sliding block fixedly connected to the sliding seat, a rotating rod rotatably arranged on the sliding block, a plug-in block slidably arranged on the sliding block, and a plug-in block connected to the plug-in block. The invention relates to a block, a protrusion fixedly connected to the block, a first spring whose two ends are respectively fixedly connected to the protrusion and the slider, and a connecting rod whose two ends are respectively movably connected to the rotating rod and the plug block; the linkage assembly comprises a movable shaft fixedly connected to the disc shaft, a first friction block fixedly installed at the end of the movable shaft, a stop block slidably arranged inside the auxiliary bracket, a second spring fixedly connected to the stop block and the auxiliary bracket at two ends, a first transmission shaft and a second transmission shaft rotatably arranged inside the auxiliary bracket, a second friction block fixedly connected to the first transmission shaft, a push rod fixedly installed on the side of the first friction block, a movable ball movably arranged at the end of the push rod, a bevel gear set for realizing transmission connection between the first transmission shaft and the second transmission shaft, a third transmission shaft and a fourth transmission shaft also rotatably arranged inside the auxiliary bracket, a first pulley set for realizing transmission connection between the second transmission shaft and the third transmission shaft, a second pulley set for realizing transmission connection between the third transmission shaft and the fourth transmission shaft, a first spur gear fixedly connected to the fourth transmission shaft, a double-sided rack and pinion slidably arranged inside the auxiliary bracket, a second straight ruler gear arranged at the internal cavity of the auxiliary bracket, and a connecting shaft for realizing fixed connection between the second straight ruler gear and the second screw rod.

[0006] Preferably, a secondary clamp is provided on the side of the main clamp, a connecting bolt is provided on the main clamp, and the connecting bolt is fixedly connected to the secondary clamp. The secondary clamp and the side of the inner cavity of the main clamp are also provided with a protrusion that cooperates with the pressure column groove.

[0007] Preferably, the fixing rod is located in the inner cavity of the auxiliary bracket, and the fixing rod is also slidably connected to the disc-shaped shaft.

[0008] Preferably, a knob is provided on the end of the rotary rod passing through the slider, and the knob is also provided with anti-slip grooves.

[0009] Preferably, the movable head is provided with a hexagonal socket for cooperating with a hexagonal wrench.

[0010] Preferably, a through hole for passing the movable shaft is formed on the first screw rod, and the movable shaft does not contact the first screw rod.

[0011] Preferably, the stop block is designed as an annular structure, and friction lines are arranged on the side of the stop block close to the second friction block, and friction lines are arranged on both end surfaces of the first friction block.

[0012] Preferably, the first spur gear and the second ruler gear are respectively located on both sides of the double-sided rack, the first spur gear is meshed with the double-sided rack, and the second ruler gear is also meshed with the double-sided rack.

[0013] Preferably, the first pulley is fixedly mounted on the top surface of the main support.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. The present invention utilizes an electric-driven winch to tighten the lifting rope, and at the same time, a main clamp is provided at the end of the lifting rope to connect with the pressure column, thereby completing the lifting of the pressure column out of the test tube, and the lifting rope also passes around the first pulley and the second pulley in sequence to change the overall pulling direction, thereby making the overall device more labor-saving, and at the same time, the electric drive reduces the requirements for operators, improves work efficiency, and reduces safety risks.

[0016] 2. The present invention also utilizes movable components, adjusting components and linkage components in coordination, so that the position of the second pulley can be adjusted according to the actual application scenario, so that the lifting rope passing around the second pulley is always in a vertical state, avoiding the phenomenon of oblique pulling of the lifting rope due to different positions of the pressure column, so that the second pulley can mainly bear the vertical force, thereby improving the stability and working efficiency of the overall device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0018] Figure 2 This is an exploded view of the main clip structure of the present invention;

[0019] Figure 3 It is a schematic diagram of the structure of the auxiliary support of the present invention;

[0020] Figure 4 It is a first cross-sectional schematic diagram of the auxiliary support structure of the present invention;

[0021] Figure 5 It is a schematic cross-sectional view of the slider structure of the present invention;

[0022] Figure 6 It is a second cross-sectional schematic diagram of the secondary support structure of the present invention;

[0023] Figure 7 This is an exploded view of the first transmission shaft structure of the present invention;

[0024] Figure 8 It is a third cross-sectional schematic diagram of the secondary support structure of the present invention;

[0025] Fig. 9 This is a fourth cross-sectional schematic diagram of the auxiliary support structure of the present invention.

[0026] In the figure: 1, main support; 2, winch; 3, lifting rope; 4, first pulley; 5, second pulley; 6, main clamp; 61, auxiliary clamp; 62, connecting bolt; 7, movable assembly; 71, auxiliary support; 72, slide rail; 73, first screw rod; 74, connecting block; 75, second screw rod; 8, adjustment assembly; 81, movable head; 82, fixed rod; 83, disc shaft; 84, slide seat; 85, slide block; 86, rotary rod; 87, plug block; 88, protrusion; 89, first spring; 810, connecting rod Rod; 9, linkage assembly; 91, movable shaft; 92, first friction block; 93, second spring; 94, stop block; 95, first transmission shaft; 96, bevel gear set; 97, second transmission shaft; 98, second friction block; 99, push rod; 910, movable ball; 911, first pulley set; 912, third transmission shaft; 913, second pulley set; 914, fourth transmission shaft; 915, first spur gear; 916, double-sided rack; 917, second ruler gear; 918, connecting shaft. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] See also Figure 1-9The present invention provides a technical solution: a pressure column lifting device, comprising a main support 1, a main clamping piece 6 connected to the pressure column, a lifting rope 3 fixedly connected to the main clamping piece 6, a first pulley 4 and a second pulley 5 for bypassing the lifting rope 3, and a winch 2 fixedly installed on the top surface of the main support 1, the end of the lifting rope 3 away from the main clamping piece 6 is also fixedly connected to the winch 2, and the main support 1 is also provided with a movable component 7, the movable component 7 includes a sub-support 71 fixedly connected to the main support 1, a slide rail 72 slidably arranged on the sub-support 71, and a first pulley 4 and a second pulley 5 rotatably arranged on the sub-support 71. A threaded rod 73, a connecting block 74 slidably arranged on the slide rail 72, and a second threaded rod 75 rotatably arranged on the slide rail 72, the connecting block 74 is also fixedly connected to the second pulley 5, the first threaded rod 73 is threadedly connected to the slide rail 72, and the connecting block 74 is threadedly connected to the second threaded rod 75; a secondary clamping piece 61 is also arranged on the side of the main clamping piece 6, and a connecting bolt 62 is also arranged on the main clamping piece 6, and the connecting bolt 62 is also fixedly connected to the secondary clamping piece 61, and a protrusion that cooperates with the pressure column groove is also arranged on the side of the secondary clamping piece 61 and the inner cavity of the main clamping piece 6, and the first pulley 4 is fixedly installed on the top surface of the main bracket 1.

[0029] The auxiliary bracket 71 is also provided with an adjustment component 8 and a linkage component 9. The adjustment component 8 includes a movable head 81 rotatably provided on the auxiliary bracket 71, a fixed rod 82 fixedly connected to the movable head 81, a slide seat 84 slidably provided on the auxiliary bracket 71, a disc-shaped shaft 83 rotatably provided on the slide seat 84, a slider 85 fixedly connected to the slide seat 84, a rotating rod 86 rotatably provided on the slider 85, an insert block 87 slidably provided on the slider 85, a protrusion 88 fixedly connected to the insert block 87, and two ends of the protrusions respectively provided on the slider 85. 88 and a first spring 89 fixedly connected to the slider 85, and a connecting rod 810 with both ends movably connected to the rotary rod 86 and the plug block 87 respectively; the fixed rod 82 is located in the internal cavity of the auxiliary bracket 71, and the fixed rod 82 is also slidably connected to the disc-shaped shaft 83, and a knob is provided on the end of the rotary rod 86 passing through the slider 85, and the knob is also provided with anti-slip grooves, and a hexagonal socket for cooperating with a hexagonal wrench is provided on the movable head 81, so that the overall structural design is more in line with actual application scenarios to meet actual usage needs.

[0030] The linkage assembly 9 includes a movable shaft 91 fixedly connected to the disc shaft 83, a first friction block 92 fixedly installed at the end of the movable shaft 91, a stop block 94 slidably arranged inside the auxiliary bracket 71, a second spring 93 whose two ends are respectively fixedly connected to the stop block 94 and the auxiliary bracket 71, a first transmission shaft 95 and a second transmission shaft 97 rotatably arranged inside the auxiliary bracket 71, a second friction block 98 fixedly connected to the first transmission shaft 95, a push rod 99 fixedly installed on the side of the first friction block 92, a movable ball 910 movably arranged at the end of the push rod 99, a bevel gear set 96 for realizing transmission connection between the first transmission shaft 95 and the second transmission shaft 97, a third transmission shaft 912 and a fourth transmission shaft 914 also rotatably arranged inside the auxiliary bracket 71, a first pulley set 911 for realizing transmission connection between the second transmission shaft 97 and the third transmission shaft 912, a second pulley set 913 for realizing transmission connection between the third transmission shaft 912 and the fourth transmission shaft 914, and a first spur gear 915 fixedly connected to the fourth transmission shaft 914. , a double-sided toothed rack 916 slidably arranged inside the auxiliary bracket 71, a second straight ruler gear 917 arranged in the internal cavity of the auxiliary bracket 71, and a connecting shaft 918 that realizes a fixed connection between the second straight ruler gear 917 and the second screw rod 75, a through hole for passing the movable shaft 91 is opened on the first screw rod 73, and the movable shaft 91 does not contact the first screw rod 73, the stop block 94 is designed as an annular structure, and the side of the stop block 94 close to the second friction block 98 is provided with friction lines, and the two sides of the first friction block 92 Friction patterns are arranged on the end faces, and the first spur gear 915 and the second ruler gear 917 are respectively located on both sides of the double-sided rack 916. The first spur gear 915 is meshed with the double-sided rack 916, and the second ruler gear 917 is also meshed with the double-sided rack 916. By adding the first pulley set 911 and the third transmission shaft 912, the transmission structure can avoid affecting the double-sided rack 916, avoid interfering with the sliding process of the double-sided rack 916, and ensure that the overall structure can operate stably and reasonably.

[0031] Working principle: first place the main support 1 on the pressure column, then clamp the auxiliary clamp 61 and the main clamp 6 on the end of the pressure column, the auxiliary clamp 61 and the protrusions inside the main clamp 6 will be engaged into the inside of the pressure column, and then the auxiliary clamp 61 and the main clamp 6 are fastened and connected together by the connecting bolts 62, and the lifting rope 3 fixedly connected to the main clamp 6 is passed around the second pulley 5 and the first pulley 4 in turn and connected to the winch 2. At this time, start the winch 2 again, which will tighten the lifting rope 3, thereby lifting the pressure column and separating the pressure column from the test tube.

[0032] When the pressure column is not in the same straight line as the main clamping piece 6, it is necessary to maintain the part of the lifting rope 3 that wraps around the second pulley 5 in a vertical state and maintain the lifting rope 3 to pull the pressure column stably, the second pulley 5 is fixed on the connecting block 74, and the connecting block 74 is slidably connected with the slide rail 72, and the connection block 74 is threadedly connected to the connecting block 74 inside the slide rail 72. The slide rail 72 is also slidably connected to the auxiliary bracket 71 fixed on the main bracket 1, and the first screw rod 73 rotatably set inside the auxiliary bracket 71 is also threadedly connected to the slide rail 72. Therefore, after the first screw rod 73 is rotated, it can push the slide rail 72, the connecting block 74 and the second pulley 5 to slide forward and backward, and after the second screw rod 75 is rotated, it can push the connecting block 74 and the second pulley 5 to slide left and right. Therefore, the second pulley 5 can realize four directions of movement, front, back, left and right, so as to achieve the purpose of changing the position of the second pulley 5 and maintaining the vertical state of the lifting rope 3.

[0033] When the first screw rod 73 is actually driven to rotate and the second pulley 5 slides back and forth, the rotary rod 86 is rotated first. Because the two ends of the connecting rod 810 are movably connected to the rotary rod 86 and the plug block 87 respectively, after the rotary rod 86 is rotated, the plug block 87 will slide toward the inside of the slider 85, so that the plug block 87 is retracted into the slider 85. At this time, the slider 85 can be pulled to slide on the auxiliary bracket 71, so that the slider 85 and the sliding seat 84 fixedly connected to the slider 85 slide toward the movable head 81. Because the disc-shaped shaft 83 rotatably arranged on the sliding seat 84 is also fixedly connected to the movable shaft 91, the first friction block 92 fixed at the end of the movable shaft 91 slides toward the first screw rod 73 until the first friction block 92 contacts the first screw rod 73. At this time, the friction pattern on the side of the first friction block 92 can form a certain friction force with the first screw rod 73, so that the first screw rod 73 can The first friction block 92 rotates with the rotation, and the rotary rod 86 can be loosened at this time. The protrusion 88 fixed on the plug block 87 also utilizes the first spring 89 to further connect with the slider 85, and then under the action of the first spring 89, the plug block 87 will slide toward the auxiliary bracket 71 and then insert into the auxiliary bracket 71 to lock the position of the slider 85 and the slide seat 84. Because the movable head 81 set on the auxiliary bracket 71 is also fixed with a fixed rod 82, and the fixed rod 82 is slidably connected with the disc shaft 83, the hexagonal wrench is inserted into the movable head 81 to drive the movable head 81 to rotate, and then the fixed rod 82, the disc shaft 83, the movable shaft 91 and the first friction block 92 will rotate synchronously, and under the friction force formed by the first friction block 92, the first screw rod 73 is driven to rotate together, thereby driving the slide rail 72, the connecting block 74 and even the second pulley 5 to slide back and forth.

[0034] When the second screw rod 75 is actually driven to rotate, causing the second pulley 5 and the connecting block 74 to slide left and right, the slider 85 is pushed in the direction away from the movable head 81, and then the first friction block 92 slides toward the first transmission shaft 95, and the push rod 99 fixed on the first friction block 92 will push the stop block 94 away. At this time, the stop block 94 does not contact the second friction block 98 fixed on the first transmission shaft 95, and the first friction block 92 contacts the second friction block 98. The friction pattern on the first friction block 92 also forms a certain friction force with the second friction block 98, so that the movable head 81 When the movable shaft 91, the first friction block 92 and other structures are driven to rotate, the second friction block 98 and even the first transmission shaft 95 rotate synchronously. Since the first transmission shaft 95 and the second transmission shaft 97 are driven by the bevel gear set 96, the second transmission shaft 97 and the third transmission shaft 912 are driven by the first pulley set 911, and the third transmission shaft 912 is driven by the fourth transmission shaft 914 fixed on the first spur gear 915 through the second pulley set 913, the first spur gear 915 will rotate inside the auxiliary bracket 71, and the first spur gear 915 will rotate inside the auxiliary bracket 71. 15 is meshed with the double-sided rack 916, and the double-sided rack 916 is meshed with the second straight-edge gear 917. After the first straight-edge gear 915 rotates, the double-sided rack 916 will slide inside the auxiliary bracket 71, thereby driving the second straight-edge gear 917 to rotate. The second straight-edge gear 917 is also fixedly connected to the second screw rod 75 through the connecting shaft 918, and the second screw rod 75 rotates synchronously, thereby driving the second pulley 5 and the connecting block 74 to slide left and right. After the second pulley 5 reaches a position that satisfies the vertical state of the lifting rope 3, the slider 85 can be restored to the initial position. , the first friction block 92 synchronously returns to the initial position, and the stop block 94 loses its restriction. Under the action of the second spring 93 fixedly connected to the stop block 94 and the auxiliary bracket 71 at both ends, the stop block 94 can slide toward the second friction block 98 until it contacts the second friction block 98. At this time, the friction pattern on the stop block 94 can form a certain friction force with the second friction block 98, thereby limiting the rotation of the first transmission shaft 95 and other structures, and then by limiting the rotation of the first spur gear 915, the double-sided rack 916 is prevented from sliding unexpectedly inside the auxiliary bracket 71.

[0035] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0036] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A pressure column lifting device, characterized in that: The invention comprises a main frame (1), a main clamping piece (6) connected to a pressure column, a lifting rope (3) fixedly connected to the main clamping piece (6), a first pulley (4) and a second pulley (5) for bypassing the lifting rope (3), and a winch (2) fixedly installed on the top surface of the main frame (1), wherein the end of the lifting rope (3) away from the main clamping piece (6) is also fixedly connected to the winch (2), and the main frame (1) is also provided with a movable component (7), and the movable component (7) comprises a first pulley (4) and a second pulley (5) connected to the main frame (1). A fixedly connected auxiliary bracket (71), a slide rail (72) slidably arranged on the auxiliary bracket (71), a first screw rod (73) rotatably arranged on the auxiliary bracket (71), a connecting block (74) slidably arranged on the slide rail (72), and a second screw rod (75) rotatably arranged on the slide rail (72), wherein the connecting block (74) is also fixedly connected to the second pulley (5), the first screw rod (73) is threadedly connected to the slide rail (72), and the connecting block (74) is threadedly connected to the second screw rod (75); The auxiliary bracket (71) is also provided with an adjustment component (8) and a linkage component (9), wherein the adjustment component (8) comprises a movable head (81) rotatably arranged on the auxiliary bracket (71), a fixed rod (82) fixedly connected to the movable head (81), a sliding seat (84) slidably arranged on the auxiliary bracket (71), a disc-shaped shaft (83) rotatably arranged on the sliding seat (84), a sliding block (85) fixedly connected to the sliding seat (84), a rotating rod (86) rotatably arranged on the sliding block (85), an inserting block (87) slidably arranged on the sliding block (85), a protrusion (88) fixedly connected to the inserting block (87), a first spring (89) having two ends fixedly connected to the protrusion (88) and the sliding block (85), and a connecting rod (810) having two ends movably connected to the rotating rod (86) and the inserting block (87). The linkage assembly (9) comprises a movable shaft (91) fixedly connected to the disc-shaped shaft (83), a first friction block (92) fixedly mounted at the end of the movable shaft (91), a stop block (94) slidably arranged inside the auxiliary bracket (71), a second spring (93) having two ends fixedly connected to the stop block (94) and the auxiliary bracket (71), a first transmission shaft (95) and a second transmission shaft (97) rotatably arranged inside the auxiliary bracket (71), a second friction block (98) fixedly connected to the first transmission shaft (95), a push rod (99) fixedly mounted on the side of the first friction block (92), a movable ball (910) movably arranged at the end of the push rod (99), and a conical spring (910) for realizing transmission connection between the first transmission shaft (95) and the second transmission shaft (97). A gear set (96), a third transmission shaft (912) and a fourth transmission shaft (914) which are also rotatably arranged inside the auxiliary bracket (71), a first pulley set (911) for realizing transmission connection between the second transmission shaft (97) and the third transmission shaft (912), a second pulley set (913) for realizing transmission connection between the third transmission shaft (912) and the fourth transmission shaft (914), a first spur gear (915) fixedly connected to the fourth transmission shaft (914), a double-sided rack (916) slidably arranged inside the auxiliary bracket (71), a second straight ruler gear (917) arranged in the internal cavity of the auxiliary bracket (71), and a connecting shaft (918) for realizing fixed connection between the second straight ruler gear (917) and the second screw rod (75).

2. A pressure column lifting device according to claim 1, characterized in that: A secondary clamp (61) is also provided on the side of the main clamp (6), and a connecting bolt (62) is also provided on the main clamp (6). The connecting bolt (62) is also fixedly connected to the secondary clamp (61), and a protrusion that cooperates with the pressure column groove is also provided on the side of the inner cavity of the secondary clamp (61) and the main clamp (6).

3. A pressure column lifting device according to claim 1, characterized in that: The fixing rod (82) is located in the inner cavity of the auxiliary bracket (71), and the fixing rod (82) is also slidably connected to the disc-shaped shaft (83).

4. The pressure column lifting device according to claim 1, characterized in that: The end of the rotary rod (86) passing through the slider (85) is provided with a knob, and the knob is also provided with anti-slip grooves.

5. The pressure column lifting device according to claim 1, characterized in that: The movable head (81) is provided with a hexagonal socket for matching with a hexagonal wrench.

6. The pressure column lifting device according to claim 1, characterized in that: The first screw rod (73) is provided with a through hole for passing the movable shaft (91), and the movable shaft (91) does not contact the first screw rod (73).

7. The pressure column lifting device according to claim 1, characterized in that: The stop block (94) is designed as an annular structure, and a friction pattern is arranged on the side of the stop block (94) close to the second friction block (98), and friction patterns are arranged on both end surfaces of the first friction block (92).

8. The pressure column lifting device according to claim 1, characterized in that: The first spur gear (915) and the second ruler gear (917) are respectively located on both sides of the double-sided rack (916); the first spur gear (915) is meshed with the double-sided rack (916); and the second ruler gear (917) is also meshed with the double-sided rack (916).

9. The pressure column lifting device according to claim 1, characterized in that: The first pulley (4) is fixedly mounted on the top surface of the main frame (1).

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