A beamless balanced energy-saving oil pumping unit

Abstract

The present invention discloses a beamless balanced energy-saving oil pumping unit, comprising a body frame, a body frame bottom plate of which is provided with a driving device for driving an oil pumping rod to move up and down, an energy storage driving device for storing or releasing energy when the driving device is working is provided above the driving device, the present invention completely solves the source of energy waste in a power transmission system and greatly reduces the cost; and adopts a power system combining hydraulic cylinder power with nitrogen energy storage power, compared with a conventional beamless oil pumping unit of the same type, the energy saving is increased by more than 30%, and the overall structure is simple, the operation automation is high, the operation is simple, the operation is reliable and stable, and the unit has the characteristics of safety and environmental protection.

Description

Technical Field

[0001] The present invention relates to an oil pumping unit, in particular to a beamless balanced energy-saving oil pumping unit which has a simple structure, is easy to operate, has reliable equipment operation, and is energy-saving and environmentally friendly, and belongs to the technical field of oil production machinery and equipment. Background Art

[0002] In the process of oil extraction, oil pumps are one of the most commonly used oil extraction equipment. Most of the oil pumps used in the prior art are beam pumps. Due to the limitations of their own physical structure, this type of oil pump has the problems of low mechanical transmission efficiency, high power consumption, difficult mechanical maintenance, and high mechanical failure rate. In order to solve these problems, researchers have designed a type of beamless oil pump.

[0003] For example, the patent number: 201621053867.4 discloses an energy-saving power system for a beamless oil pump, including a beamless oil pump body, an energy-saving power system is installed on the top platform of the beamless oil pump body, the power system includes a motor that can be rotated forward and reverse, a coupling is connected to the output shaft of the motor, the other end of the coupling is connected to the input shaft of the reducer, the output shaft of the reducer is connected to the traction belt roller, and a settable frequency converter is provided in the intelligent control cabinet, which can control the forward and reverse rotation of the motor. The power system is intelligently controlled by the frequency converter in the intelligent control cabinet, thereby realizing the adjustment of any speed and any stroke of the power system.

[0004] The above-mentioned type of oil pumping unit can drive the sucker rod to move up and down to pump oil, but the driving mechanism includes a motor, a reducer, a roller, a belt and a counterweight device. The overall driving mechanism is complex and requires a high-power motor to drive it, which will undoubtedly increase the overall weight, cost and energy consumption of the oil pumping unit, causing adverse effects on production, transportation and cost control; and when oil is produced, the up and down running load weight of the sucker rod is not equal, and the upward load weight is twice that of the downward load weight, and the existing method of balancing the load during operation is to use a counterweight device for balancing. Due to the continuous change of the downhole load, it is difficult to achieve the best stability in the operation of the oil pump, and it is impossible to solve the working balance problem of the operating machine, and the maximum energy saving effect cannot be achieved. Summary of the invention

[0005] The main technical problem to be solved by the present invention is to provide a beamless balanced energy-saving oil pumping unit which has the advantages of simple structure, easy operation, reliable equipment operation, energy saving and environmental protection.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A beamless balanced energy-saving oil pumping unit comprises a body frame, a body frame bottom plate of which is provided with a driving device for driving an oil pumping rod to move up and down, and an energy storage driving device for storing or releasing energy when the driving device is working is provided above the driving device.

[0008] The following is a further optimization of the above technical solution by the present invention:

[0009] The driving device comprises a power cylinder installed on the bottom plate of the machine frame, the output end of the power cylinder is fixedly connected with a moving plate, and the bottom plate of the machine frame and the moving plate are provided with a gear train multi-range and multi-force assembly.

[0010] Further optimization: the gear train multi-range and multi-force assembly includes rotating pulleys arranged on the body frame bottom plate and the movable plate and located on the left and right sides of the power cylinder, and each rotating pulley is respectively provided with a plurality of wheel grooves.

[0011] Further optimization: the rotating pulley located on the same side of the power cylinder is a group of wheel trains, each of which is wound with a tension belt, one end of the tension belt is fixedly connected to the bottom plate of the body frame, and the free end of the tension belt is sequentially wound in the wheel groove of the rotating pulley of the group of wheel trains.

[0012] Further optimization: the energy storage drive device includes a balancing cylinder symmetrically arranged with the power cylinder, the fixed end of the balancing cylinder is fixedly mounted on the body frame, and the telescopic end of the balancing cylinder is fixedly mounted on the movable plate on the side opposite to the power cylinder.

[0013] Further optimization: the balancing cylinder is connected to an accumulator, and the accumulator is filled with nitrogen.

[0014] Further optimization: the telescopic end of the power cylinder retracts to drive the moving plate downward, and the moving plate drives the telescopic end of the balancing cylinder to extend, causing the cavity in the balancing cylinder to decrease, the compressed gas to expand, and the gas pressure to increase. The high-pressure gas enters the accumulator, and the accumulator stores energy.

[0015] Further optimization: the telescopic end of the power cylinder extends to drive the movable plate upward, and the movable plate drives the telescopic end of the balancing cylinder to retract, causing the cavity in the balancing cylinder to increase, and the accumulator releases energy to cooperate with the power cylinder to synchronously drive the movable plate upward.

[0016] Further optimization: two sets of reversing guide wheels for guiding the movement of the tension belt are arranged on one side of the driving device, and the axes of the two sets of reversing guide wheels are arranged in parallel.

[0017] Further optimization: a transition wheel and a straightening wheel are movably arranged on the upper top platform above the body frame, and a traction belt is wrapped around the transition wheel and the straightening wheel. One end of the traction belt is connected to the sucker rod, and the other end of the traction belt is located in the body frame and fixedly connected to the free end of the tension belt.

[0018] The present invention adopts the above technical solution. When in use, the motor in the motion control system is first started, and the hydraulic pump outputs power to pressurize the hydraulic oil in the hydraulic station and reaches the P port of the electromagnetic reversing valve through the one-way valve. At this time, the right electromagnet of the electromagnetic reversing valve is energized, and the pressure oil reaches the A port and B port of the electromagnetic reversing valve at the same time, and then is guided into the power cylinder through the guide pipe. At this time, the power cylinder differentially extends quickly to push the moving plate to drive the rotating pulley installed on the moving plate to move upward, pull the tension belt and the traction belt upward, and make the sucker rod perform an upward action.

[0019] At this time, the accumulator releases energy, causing the balance cylinder and the power cylinder to act simultaneously to drive the oil pumping upward action.

[0020] When the oil cylinder rises to the specified position, the electromagnetic reversing valve reverses, the right electromagnet loses power, and the left electromagnet is energized. The pressure oil enters the B port of the electromagnetic reversing valve through the P port of the electromagnetic reversing valve, and is then guided into the upper oil chamber of the piston rod of the power cylinder through the guide pipe, causing the power cylinder to retract and drive the movable plate to drive the rotating pulley installed on the movable plate to move downward, pulling the tension belt and the traction belt downward, causing the sucker rod to move downward.

[0021] When the power cylinder retracts, the oil in the lower oil chamber flows to the T port through the A port of the electromagnetic reversing valve, and then flows back to the hydraulic station through the return oil filter to complete the downward movement of the sucker rod.

[0022] At this time, the telescopic end of the balance cylinder extends out, and the accumulator stores energy at the same time, thereby realizing the up and down movement of the sucker rod to complete the oil pumping work.

[0023] The present invention adopts the above technical solution, which is ingenious in conception and reasonable in structure, and completely removes the counterweight box and other mechanisms of the prototype, thereby saving nearly one-third of the weight of the prototype, completely solving the root cause of energy waste in the power transmission system, and greatly reducing costs;

[0024] It adopts a power system that combines hydraulic cylinder power with nitrogen energy storage power. The total power motor power is 3-4KW. Compared with the same type of conventional beamless pumping unit, it can increase energy saving by more than 30%, and compared with the beam pumping unit, it can save energy by more than 70%;

[0025] And the whole machine has no mechanical counterweight device, and adopts the balance cylinder and accumulator to balance the load automatically, so that the pumping unit can be started from installation to operation shutdown and then restarted without the assistance of external lifting equipment, which is easy to use;

[0026] The overall structure is simple, the operation is highly automated, the operation is simple, the operation is reliable and stable, and it is safe and environmentally friendly. It completely avoids problems such as air leakage, water leakage, electric leakage, and oil leakage, and the overall structure is easy to maintain.

[0027] In addition, the driving device adopts a wheel system with multiple range and multiple force assembly composed of double pulleys. Through the combined linear motion of the power cylinder and the balance cylinder, the tension belt wrapped around the double pulleys can produce increased distance performance, so that the tension belt drives the traction belt and the bare rod to reciprocate and achieve the purpose of oil production.

[0028] The present invention is further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention;

[0030] Figure 2 It is a schematic diagram of the structure of the driving device in an embodiment of the present invention;

[0031] Figure 3 It is a schematic diagram of the upward force of the sucker rod in an embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of the downward power of the sucker rod in an embodiment of the present invention;

[0033] Figure 5 Schematic diagram of the structure of the power system in an embodiment of the present invention.

[0034] In the figure: 1-machine frame; 11-machine frame bottom plate; 12-upper platform; 13-base; 14-pull rod; 15-safety workbench; 16-protective cover; 2-sucker rod; 21-oil well; 22-Christmas tree; 23-seal; 3-transition wheel; 4-righting wheel; 5-traction belt; 51-connector; 52-upper dead center; 53-lower dead center; 6-power cylinder; 61-moving plate; 62-rotating pulley; 63-tension belt; 64-reversing guide wheel; 7-balancing cylinder; 8-accumulator; 9-hydraulic station; 91-hydraulic pump; 92-electromagnetic reversing valve; 93-filter; 94-pressure gauge; 95-thermometer; 96-liquid level gauge; 10-buffer protection device. DETAILED DESCRIPTION

[0035] Example: Figure 1-5 As shown, a beamless balanced energy-saving oil pumping unit includes a body frame 1, a body frame bottom plate 11 of which is provided with a driving device for driving a sucker rod 2 to move up and down, and an energy storage driving device for storing or releasing energy when the driving device is working is provided above the driving device.

[0036] The driving device comprises a power cylinder 6 mounted on a machine frame bottom plate 11 , an output end of the power cylinder 6 is fixedly connected to a moving plate 61 , and a gear train multi-range and multi-force assembly is provided on the machine frame bottom plate 11 and the moving plate 61 .

[0037] The gear train multi-range and multi-force assembly includes a rotating pulley 62 arranged on the body frame bottom plate 11 and the moving plate 61 and located on the left and right sides of the power cylinder 6. The rotating pulley 62 is fixedly connected to the body frame bottom plate 11 and the moving plate 61 through a support frame.

[0038] The rotating pulleys 62 located on the same side of the power cylinder 6 form a set of wheel trains, and a tension belt 63 is wound around each set of wheel trains. One end of the tension belt 63 is fixedly connected to the bottom plate 11 of the body frame.

[0039] Each rotating pulley 62 is provided with a plurality of wheel grooves, and the free ends of the tension belt 63 are sequentially wound in the wheel grooves of the rotating pulleys 62 of the wheel train.

[0040] With this design, the power cylinder 6 can output power to drive the moving plate 61 to drive the rotating pulley 62 installed on the moving plate 61 to move, thereby changing the spacing between the wheel trains, and then changing the distance between the tension belts 63 between the wheel trains, and the distance that the power cylinder 6 drives the moving plate 61 to move multiplied by the number of wheel grooves is the moving distance of the free end of the tension belt 63.

[0041] The energy storage drive device includes a balancing cylinder 7 symmetrically arranged with the power cylinder 6 , the fixed end of the balancing cylinder 7 is fixedly mounted on the body frame 1 , and the telescopic end of the balancing cylinder 7 is fixedly mounted on the moving plate 61 on the side opposite to the power cylinder 6 .

[0042] The balance cylinder 7 is connected to an accumulator 8, and the accumulator 8 is filled with nitrogen. The accumulator 8 is fixedly mounted on the body frame 1, and the accumulator 8 is a prior art.

[0043] The telescopic end of the power cylinder 6 retracts to drive the movable plate 61 downward, and the movable plate 61 drives the telescopic end of the balancing cylinder 7 to extend, causing the cavity in the inner chamber of the balancing cylinder 7 to decrease, the compressed gas to expand, and the gas pressure to increase. The high-pressure gas enters the accumulator 8, and the accumulator 8 stores energy.

[0044] The telescopic end of the power cylinder 6 extends to drive the movable plate 61 upward, and the movable plate 61 drives the telescopic end of the balancing cylinder 7 to retract, causing the cavity of the inner chamber of the balancing cylinder 7 to increase, and the accumulator 8 releases energy to cooperate with the power cylinder 6 to synchronously drive the movable plate 61 upward.

[0045] With this design, the balancing cylinder 7 and the accumulator 8 can store energy when the movable plate 61 is moving downward. When the power cylinder 6 drives the movable plate 61 upward, the accumulator 8 releases energy, so that the balancing cylinder 7 cooperates with the power cylinder 6 to synchronously drive the movable plate 61 upward, thereby realizing a power system combining the pressure cylinder power and the nitrogen energy storage power, thereby greatly reducing the oil pressure required by the power cylinder 6 and the total power motor power to 3-4KW. Compared with the same type of non-beam pumping unit, the energy saving rate is increased by more than 30%; compared with the conventional beam pumping unit, the energy saving rate is more than 70%.

[0046] Two sets of reversing guide wheels 64 for guiding the movement of the tension belt 63 are arranged on one side of the driving device, and the axes of the two sets of reversing guide wheels 64 are arranged in parallel.

[0047] Each group of reversing guide wheels 64 includes two reversing guide wheels 64 , each of which is used to guide the movement of the tension belt 63 .

[0048] A transition wheel 3 and a straightening wheel 4 are movably arranged on the upper top platform 12 above the machine frame 1, and the axes of the transition wheel 3 and the straightening wheel 4 are arranged in parallel.

[0049] The transition wheel 3 and the straightening wheel 4 are both independent bearing mechanisms, and both ends of the rotating shafts of the transition wheel 3 and the straightening wheel 4 are respectively installed on the upper top platform 12 of the body frame 1 through bearing supports.

[0050] A traction belt 5 is wound around the transition wheel 3 and the righting wheel 4, and one end of the traction belt 5 close to the righting wheel 4 is perpendicular to the wellhead of the oil well 21 on the ground and connected to the sucker rod 2. One end of the traction belt 5 close to the transition wheel 3 is located in the body frame 1 and is fixedly connected to the free end of the tension belt 63.

[0051] With this design, the transition wheel 3 and the straightening wheel 4 can be used to guide and carry the movement of the traction belt 5, and the driving device outputs power so that the tension belt 63 can drive the traction belt 5 to move, thereby driving the sucker rod 2 upward or downward to produce oil.

[0052] The lower end of the traction belt 5 is fixedly connected to the sucker rod 2 via a connector 51. The movement of the traction belt 5 drives the lower end of the sucker rod 2 to move upward or downward, thereby extending into or pulling out of the oil well 21 to achieve oil production.

[0053] The traction belt 5 is provided with an upper stop point 52 and a lower stop point 53 respectively at positions close to the sucker rod 2 and the straightening wheel 4 . The upper stop point 52 and the lower stop point 53 are used to limit the moving distance of the traction belt 5 .

[0054] A Christmas tree 22 is fixedly installed on the wellhead of the oil well 21 , and a sealer 23 for improving the sealing performance of the connection between the Christmas tree 22 and the sucker rod 2 is installed above the Christmas tree 22 and at the connection between the sucker rod 2 .

[0055] A buffer protection device 10 is provided at a position near the tension belt 63 in the body frame 1 for buffering and braking when the sucker rod 2 breaks unexpectedly.

[0056] In this embodiment, the buffer protection device 10 is a limit plate, which is fixedly installed in the body frame 1. A limit hole is provided on the limit plate, and the tension belt 63 is passed through the limit hole. A limit block is fixedly provided on the tension belt 63 for use with the limit hole.

[0057] A base 13 for fixing is disposed at the bottom of the machine frame 1 , a pull rod 14 is disposed at one end of the base 13 , and the other end of the pull rod 14 is connected to the machine frame 1 to form a stable triangular structure.

[0058] A safety workbench 15 is provided on the machine frame 1 near the upper platform 12 , and a protective cover 16 for protecting the transition wheel 3 , the straightening wheel 4 , and the traction belt 5 is installed on the top of the machine frame 1 .

[0059] like Figure 5 As shown, the power cylinder 6 is provided with hydraulic force by the power system. Under the action of hydraulic pressure, the power cylinder 6 drives the movable plate 61 to drive the rotating pulley 62 installed on the movable plate 61 to move, thereby changing the spacing between the wheel trains, and then pulling the sucker rod 2 up and down through the tension belt 63 and the traction belt 5.

[0060] The power system includes a hydraulic station 9, in which a hydraulic pump 91 is arranged. The hydraulic pump 91 is driven by a motor. The output port of the hydraulic pump 91 is connected to the P port of the electromagnetic reversing valve 92 through a guide pipe. The A port and the B port of the electromagnetic reversing valve 92 are connected to the lower oil chamber and the upper oil chamber of the power cylinder 6 through the guide pipe. The T port of the electromagnetic reversing valve 92 is connected to the hydraulic station 9 through a filter 93.

[0061] The electromagnetic reversing valve 92 is a three-position four-way electromagnetic reversing valve.

[0062] A one-way valve is provided on the guide pipe between P of the electromagnetic reversing valve 92 and the hydraulic station 9 .

[0063] During operation, the motor drives the hydraulic pump 91 to output power to pressurize the hydraulic oil in the hydraulic station 9 and reach the P port of the electromagnetic reversing valve 92 through the one-way valve. At this time, the right electromagnet of the electromagnetic reversing valve 92 obtains the pressure oil and reaches the A port and B port of the electromagnetic reversing valve 92 at the same time, and then is guided into the power cylinder 6 through the guide pipe. At this time, the power cylinder 6 differentially extends quickly to push the moving plate 61 to drive the rotating pulley 62 installed on the moving plate 61 to move upward, pulling the tension belt 63 and the traction belt 5 upward, so that the sucker rod 2 performs an upward action.

[0064] When the right electromagnet of the electromagnetic reversing valve 92 loses power and the left electromagnet is energized, the pressure oil enters the B port of the electromagnetic reversing valve 92 through the P port of the electromagnetic reversing valve 92, and is then guided into the oil chamber on the piston rod of the power cylinder 6 through the guide pipe, causing the power cylinder 6 to retract and drive the movable plate 61 to drive the rotating pulley 62 installed on the movable plate 61 to move downward, pulling the tension belt 63 and the traction belt 5 downward, causing the sucker rod 2 to move downward.

[0065] The outlets of the A port and the B port of the electromagnetic reversing valve 92 are respectively connected to pressure gauges 94 for constantly monitoring the oil pressure in the A port and the B port of the electromagnetic reversing valve 92 .

[0066] The hydraulic station 9 is also provided with a thermometer 95 for constantly monitoring the temperature of the hydraulic oil in the hydraulic station 9 .

[0067] The hydraulic station 9 is also provided with a liquid level meter 96 for constantly monitoring the liquid level of the hydraulic pressure in the hydraulic station 9 .

[0068] like Figure 1-5 As shown, when in use, first start the motor in the motion control system, the hydraulic pump 91 outputs power to pressurize the hydraulic oil in the hydraulic station 9 and reaches the P port of the electromagnetic reversing valve 92 through the one-way valve. At this time, the right electromagnet of the electromagnetic reversing valve 92 is energized, and the pressure oil reaches the A port and B port of the electromagnetic reversing valve 92 at the same time, and then is guided into the power cylinder 6 through the guide pipe. At this time, the power cylinder 6 differentially extends quickly to push the moving plate 61 to drive the rotating pulley 62 installed on the moving plate 61 to move upward, pulling the tension belt 63 and the traction belt 5 upward, so that the sucker rod 2 performs an upward action.

[0069] At this time, the accumulator 8 releases energy, so that the balance cylinder 7 and the power cylinder 6 act simultaneously to drive the pumping 2 to move upward.

[0070] When the oil cylinder rises to the specified position, the electromagnetic reversing valve 92 reverses, the right electromagnet loses power, and the left electromagnet is energized, and the pressure oil enters the B port of the electromagnetic reversing valve 92 through the P port of the electromagnetic reversing valve 92, and is then guided into the oil chamber on the piston rod of the power cylinder 6 through the guide pipe, so that the power cylinder 6 retracts and drives the movable plate 61 to drive the rotating pulley 62 installed on the movable plate 61 to move downward, pulling the tension belt 63 and the traction belt 5 downward, so that the sucker rod 2 moves downward.

[0071] When the power cylinder 6 retracts, the oil in the lower oil chamber flows to the T port through the A port of the electromagnetic reversing valve 92, and then flows back to the hydraulic station 9 through the return oil filter 93, completing the downward movement of the sucker rod 2.

[0072] At this time, the telescopic end of the balance cylinder 7 extends out, and the accumulator 8 stores energy at the same time, thereby realizing the up and down movement of the sucker rod 2 to complete the oil pumping work.

[0073] For those skilled in the art, according to the teachings of the present invention, without departing from the principles and spirit of the present invention, changes, modifications, substitutions and variations made to the implementation methods are still within the protection scope of the present invention.

Claims

1. A beamless balanced energy-saving oil pumping unit, comprising a frame (1), characterized in that: A driving device for driving the sucker rod (2) to move up and down is arranged on the frame bottom plate (11) of the frame (1), and an energy storage driving device for storing or releasing energy when the driving device is working is arranged above the driving device; The driving device comprises a power cylinder (6) mounted on a machine frame bottom plate (11); an output end of the power cylinder (6) is fixedly connected to a moving plate (61); and a gear train multi-range and multi-force assembly is provided on the machine frame bottom plate (11) and the moving plate (61); The energy storage drive device comprises a balancing cylinder (7) symmetrically arranged with the power cylinder (6), the fixed end of the balancing cylinder (7) is fixedly mounted on the machine frame (1), the telescopic end of the balancing cylinder (7) is fixedly mounted on a moving plate (61) on the side opposite to the power cylinder (6), and the balancing cylinder (7) is connected to an accumulator (8); The telescopic end of the power cylinder (6) retracts to drive the movable plate (61) downward, and the movable plate (61) drives the telescopic end of the balancing cylinder (7) to extend, causing the cavity of the inner chamber of the balancing cylinder (7) to decrease, and the compressed gas expands to increase the gas pressure. The high-pressure gas enters the accumulator (8), and the accumulator (8) accumulates energy. At this time, the sucker rod (2) moves downward; the telescopic end of the power cylinder (6) extends to drive the movable plate (61) upward, and the movable plate (61) drives the telescopic end of the balancing cylinder (7) to retract, causing the cavity of the inner chamber of the balancing cylinder (7) to increase. The accumulator (8) releases energy to cooperate with the power cylinder (6) to synchronously drive the movable plate (61) upward. At this time, the balancing cylinder (7) and the power cylinder (6) act simultaneously to drive the sucker rod (2) to move upward.

2. The beamless balanced energy-saving oil pumping unit according to claim 1 is characterized in that: The multi-range and multi-force wheel train assembly comprises rotating pulleys (62) arranged on a machine frame bottom plate (11) and a movable plate (61) and located on the left and right sides of the power cylinder (6), and each rotating pulley (62) is provided with a plurality of wheel grooves.

3. The beamless balanced energy-saving oil pumping unit according to claim 2 is characterized in that: The rotating pulleys (62) located on the same side of the power oil cylinder (6) form a group of wheel trains, and a tension belt (63) is wound around each group of wheel trains. One end of the tension belt (63) is fixedly connected to the bottom plate (11) of the machine frame, and the free end of the tension belt (63) is sequentially wound in the wheel groove of the rotating pulley (62) of the group of wheel trains.

4. The beamless balanced energy-saving oil pumping unit according to claim 1 is characterized in that: The accumulator (8) is filled with nitrogen.

5. The beamless balanced energy-saving oil pumping unit according to claim 3 is characterized in that: Two groups of reversing guide wheels (64) for guiding the movement of the tension belt (63) are arranged on one side of the driving device, and the axes of the two groups of reversing guide wheels (64) are arranged in parallel.

6. The beamless balanced energy-saving oil pumping unit according to claim 5 is characterized in that: A transition wheel (3) and a straightening wheel (4) are movably arranged on the upper top platform (12) above the machine frame (1), and a traction belt (5) is wound around the transition wheel (3) and the straightening wheel (4). One end of the traction belt (5) is connected to the sucker rod (2), and the other end of the traction belt (5) is located inside the machine frame (1) and fixedly connected to the free end of the tension belt (63).

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