SI24995A - A mechanical-hydraulic system with a pressure regulator for maintaining constant power of the traction force of the winch - Google Patents

Abstract

The invention belongs to the field of mechanical engineering, more precisely to the field of hydraulic systems with a hydraulic accumulator as an additional source of hydraulic pressure energy, especially suitable for devices with uneven consumption. The invention also belongs to the region of pressure regulators to provide a constant traction force of forestry winches. The essence of a mechanical-hydraulic system with a pressure controller in order to maintain the constant power of the towing force of the winch is that the pusher cylinder, when winding each new layer of the tow rope on the drum, is welded to the drum, rotating the axis of the forks bearing the pushing cylinder. The fork shaft rotation causes the shaft to move, which pushes the pressure regulator piston one step, causing an increase in the oil pressure, which increases the thrust of the cylinder piston to the clutches, which increases the drum moment. The invention is based on a mathematical algorithm defined by the distances "e", "f" and "g", which causes the pressure regulator piston to move, for each displacement of the pushing cylinder or fork axle, due to the new layer of the tow rope on the drum. By virtue of varying the distances "e", "f" and "g", the hydraulic system's oil pressure is reduced or reduced, and the constant towing torque of the winch is maintained.

Description

The field of technology

The invention belongs to the field of mechanical engineering, more specifically to the field of hydraulic systems with a hydraulic accumulator as an additional source of hydraulic pressure energy, particularly suitable for devices with uneven consumption. The invention also falls within the scope of pressure regulators for providing constant traction of forestry winches.

A technical problem

A technical problem to be solved by the present invention is the construction of such a hydraulic system for controlling and controlling the winding drum winch, which together with the mechanical assembly of the winding drum will allow the winch to be kept almost constant. When the winch is in use, the diameter of the drum changes depending on the number of layers of coiled wire, which in turn results in a change in the pulling force of the winch. It is an object of the invention to design the individual functional elements of the winch together with the elements of the hydraulic system, which would make it possible to maintain a constant winch force even when the entire tow rope is wound or almost unscrewed. When using the winch, there may be a situation where it is necessary to regulate the tractive force according to the situation in the work process. If the winch drops traction by increasing the rope radius on the drum until the resistance force exceeds the traction force, the load is stopped because the clutch blades start to slip, which is problematic in practice. The constant pulling force enables optimum clutch operation. It is an object of the invention to provide a structural solution for the mechanical parts of the drum, together with its auxiliary parts, which will allow the hydraulic parameters to be influenced.

The prior art

Conventional forestry winches have the highest pulling force when the drum is empty or at the first layer of rope on the drum. The clutch blades are compressed with constant force, so a constant torque is always transmitted from the drive shaft to the winch drum. By winding the rope on the drum, the radius of the back layer of the rope on the drum increases, so the pulling force falls, since the torque is equal to the product of the force and the distance of the force line from the axis. The known solutions to optimize winch traction due to the influence of the number of threads on the winch drum are EP2565144 "Winch" and SI24108 "Forest winch with controlled winding of the tow rope and protecting it against overload".

The winch described in EP2565144 comprises a drive shaft, a rope winding drum, a clutch drum to transfer the rotary movement of the drive shaft to a rope drum, a drum brake to brake the rope drum, and a rope drainage device with at least one rope. The rope can be driven for rope unwinding and via a transmission having a rope drain clutch, with the rope connected to the drive shaft. The invention is characterized in that the rope drain clutch is formed by a hydraulically actuated clutch. The solution differs from the present invention, where an otherwise hydraulically controlled mechanism is involved in providing a mechanical deflection of the arms in order to maintain the winch's almost constant pulling force.

According to Slovenian patent no. 24108 is a well-known solution of a forestry winch in which the rope winding is controlled in such a way that the ropes on the surface of the winding drum are arranged side by side without crossing and overlapping, while preventing overloading of the tow rope and other elements of the winch drive assembly due to towing a heavy load. For this purpose, the winch is provided, in the area between the upper pulley and the winding drum, with a freely rotatable or at least suitable rotary steering assembly, which optionally includes a dynamometer for measuring the tensile force in the tow rope, so that the drive of the drum can be controlled depending on the load rope load measured at each time.

Known solutions in practice do not solve the technical problem in the way solved by the present invention, which allows the regulation of oil pressure depending on the size of the diameter of the coiled wire rope, which in turn means maintaining the almost constant pulling force of the winch rope.

Description of solution to a technical problem

The point of a mechanical-hydraulic system with a pressure regulator to keep the winch's pulling force constant is that the thrust roller moves away from the winch drum by winding each new layer of the draw rope, rotating the fork axis carrying the thrust roller. The rotation of the fork axis causes the rod to be displaced, which pushes the pressure regulator piston one stage, causing the oil pressure to increase, which causes the cylinder piston thrust to increase, thereby increasing the drum torque. The invention is based on a mathematical algorithm defined by distances "e", "f" and "g", which causes the displacement of the pressure regulator piston, for each displacement of the thrust roller or fork axis, due to the new layer of traction cable on the drum. By increasing or decreasing the hydraulic system oil pressure in accordance with changing distances "e", "f" and "g", the winch's almost pulling force is maintained.

The mechanical-hydraulic system with a pressure regulator for precisely determining the winch's pulling force will be described in more detail below with the help of figures showing:

Figure 1 is a hydraulic diagram of a system with a pressure regulator,

Figure 2 is a schematic illustration of a constant or variable traction control system,

Figure 3 mechanical-hydraulic system according to the invention,

Figure 4 is a schematic representation of the drum rope radio,

Figure 5 is a graphical representation of the tractive force adjustment options.

Pump 3 fills through the non-return valves 4 and 7 the hydraulic accumulator 9 to the working pressure set on the relief valve 5. When the oil in the hydraulic accumulator 9 reaches the set operating pressure, the relief valve 5 opens and stays there for as long as it is in the hydraulic accumulator 9 the pressure does not drop by a certain value of approximately 10 to 15 bar. The oil flows freely to the flow regulator 16 and the control valve 6 when valve 5 is open. There is less resistance on the valve side 6, so the oil flows through it into the oil tank 1. Because of this hydraulic equipment, pump 3 operates most of the time at lower pressure and otherwise up to 10 bars. If the user selects the rope unwinding function, valves 6 (right) and 11 (right) switch at the same time. The oil flows from the pump through the valve 6 to the flow regulator 16, the non-return valve 17 to the hydraulic motor 19, which drives the retractor through which the rope 31 is routed from the winch drum 30. At the same time, the oil from the hydraulic accumulator 9 activates the brake cylinder 14 through the throttle 8, the valve 11 and the adjustable throttle 13, thus releasing the drum brake so that the rope on the drum 31 begins to unwind due to the pulling force in the rope 31 caused by the hydraulic motor 19. Pressure in the supply line to the motor 19 increases to 50-70 bar.

When the user activates the winding of the rope, valves 11 (left) and valve 20 (right) are switched and oil flows from the hydraulic accumulator 9 through the throttle 8, valve 11 and pressure regulator 21 activates the clutch cylinder 15.

If the pressure in the hydraulic accumulator 9 drops to a certain value, the relief valve 5 closes and the pump fills the hydraulic accumulator 9 to the set operating pressure.

When the oil flows through valve 5 to a common point with valve 6 and tank, it flows to the control valve 20, which is connected in parallel with the hydraulic cylinder 15 of the clutch. In the case of winding, valves 11 and 20 must be switched simultaneously to activate the clutch hydraulic cylinder 15. When the winding is started, the left part of the valve 11 and the right part of the valve 20 are switched simultaneously. The oil from the accumulator flows towards the hydraulic cylinder 15 of the clutch and the oil cannot flow through the right part of the valve 20. After the winding is released, valves 11 and 20 switch in the starting position. If one of the valves becomes blocked, the oil can always flow freely into the tank through valve 11 or 20. The hydraulic circuit includes a pressure regulator 21 and a non-return valve 22 connected to the node of the tank 1, valve 6 and valve 20 on one side and to the other side with a pressure regulator 21.

Conventional forestry winches have a maximum pulling force F when the drum 30 is empty or at the first layer of rope 31 on the drum 30. The clutch blades are compressed with constant force, so a constant rotating speed is always transmitted from the drive shaft to the winch drum 30.

moment M. By winding rope 31 onto drum 30, the radius "r" of the back layer of the rope on the drum increases, so the pulling force F falls, since M = r x F.

As shown in Figure 3, the first layer of rope on the drum has a radius of "rn" and the last intended layer of rope on the drum has a radius of "rz". Working pressure is "after". When the thrust roller is at the level of the first layer of rope on the drum, the clutch has a reduced working pressure, namely pn = after x rn / rz;

As a result, the working pressure "p" is lower when the drum is empty. When all the rope is wound on the drum, the working pressure "p" is equal to the pressure "po". When some rope is unwound and "r" is arbitrary, the pressure value can be calculated by the equation:

p = po x r / rz.

Pressure "p" in pressure regulator 21 is set by shifting levers or. levers, therefore, by selecting the levers "e" and "g" and the length "f" of the rod 36.

The mechanical-hydraulic system of the invention has a thrust roller 33 mounted on forks 34, which oscillate about the lower axis 34a, to which a spring 35 is mounted on one side and a mounting element 36a for the rod 36 on the other side. between the center line of the axis 34a, to which the lower part of the mount 35a is fixed, and the center line of the upper part of the mount 35a, to which the spring 35 is clamped. On the other side of the axis 34a, a fastening element 36a is engaged with a groove 36a 'where one end of the bar 36 is mounted. which is preferably a threaded rod. The second part of the rod 36 is pivotally engaged in the bracket 36b, which with the part 36b 'touches the piston of the control valve 21. The distance "e" is between the center line of the axis 34a and the place in the groove 36a', where the first part of the rod 36 is fixed. The distance "f" is between the first portion of the rod 36 and the center line of the singing of the second portion of the rod 36 in the carrier 36b. The prestressed spring 35 pulls the fork 34 on the lever "g", thereby pushing the thrust roller 33 onto the reel 30 with a coiled cord 31.

By winding the rope 31 onto the drum 30, the radius of the current layer of the rope on the drum increases. The thrust roller 33, which is mounted on the forks 34, therefore increasingly moves away from the axis of the drum 30,

as the forks 34 rotate about the axis 34a. The rotation of the forks 34, however, causes the horizontal movement of the rod 36 along the groove 36a 'of the fastener 36a. The horizontal displacement of part 36b 'of attachment 36b is adjustable via the distances' f' and 'e'. The rod 36 pushes the pressure regulator piston 21 over the part 36b 'of the adapter 36b, causing the oil pressure to rise. If the rod 36 is moved, the pressure regulator piston 21 is released due to the offset of part 36b 'and the oil pressure is lowered.

Depending on the design of the pressure regulator 21, the piston of the non-return valve 22 may be pushed through the rod 36 for a certain length of displacement of the portion 36b 'of the adapter 36b towards the control valve 21. The starting position of part 36b 'to be fully extended. In doing so, the thrust roller 33 on the drum 30 is pushed to the first layer of rope. The oil pressure released by the pressure regulator 21 to the clutch cylinder is "pn" and is at a minimum of about 90 bar. The relationship between the displacement of the thrust cylinder 33 from the axis of the drum 30 and the displacement of the part 36b 'of the adapter 36b towards the control valve 21 is approximately linear. Thus, as the radius of the layer on the drum 30 increases, the oil pressure up to the clutch cylinder 15 increases linearly, when the rope layer on the drum radius "rz" reaches, the pressure regulator piston 21 is maximally suppressed by the rod 36 and the oil pressure up to the clutch cylinder 15 is greatest. .

Figure 4 shows the winch drum and the diameter "m" and the diameter "rz" and the force F on the vertical axis, where the areas A, B, C, D depend on the selected magnitudes of the force Fn, so that F is constant. Figure 4 shows that it is possible to choose the magnitude of the force Fn by varying the distances "e", "g" and "f", with the force F approximately varying linearly. The distance adjustments "e", "g" and "f" are enabled by changing the position of the springs 35 and both ends of the bar 36.

The result of the previously described construction of the drum 30 with a coiled rope 31, a fork 34, a rod 36 directly connected to the pressure regulator 21, results in an almost constant pulling force F for the entire winding area of the rope 31 onto the drum 30, as well as the possibility of adjusting different pulling force F by specifying distances "e", "g" and "f".

Claims (4)

Patent claims Mechanical-hydraulic system with pressure regulator to maintain the constant power of the towing force of the winch, characterized in that the pusher cylinder moves away from each new layer of the tow rope on the drum of the winch by rotating the axis of the forks carrying the pushing cylinder; the rotation of the fork shaft causes the shaft to move, which pushes the pressure regulator pressure piston one step, causing the oil pressure to increase, increasing the thrust of the cylinder piston to the clutch, which increases the drum moment; that the distances "e", "f" and "g" change due to each displacement of the pushing cylinder or axle fork, due to the new layer of the tow rope on the drum and, consequently, the movable parts of the fittings, the pressure regulator is closed or opened, which increases or reduces the oil pressure of the hydraulic system ; in accordance with the variation of the distances 'e', 'f' and 'g' and directly connected forks of the pushing cylinder, the springs and the rod, the almost constant towing force of the winch is maintained. 2. Mechanical-hydraulic with pressure regulator for maintaining a constant traction force according to claim 1, characterized in that the pushing cylinder (33) pushes the rope (31) on the drum (30); characterized in that the pushing cylinder (33) is rotatably engaged on the forks (34) which swing around the lower axis; characterized in that the forks (34) have a variable length of the arms (e) and (g); characterized in that between the lever (e) and the proportional pressure regulator (21), the rod 36 of the length (f) is adjustable; to pull the spring (35) to pull the fork (34) on the lever (g) and push the pushing cylinder (33) to the rope (31) and the drum (30). A mechanical hydraulic system with a pressure regulator for maintaining a constant traction force according to claim 2, characterized in that the pressure of the pressure (p) in the pressure regulator (21) is adjusted by the movement of the levers or, lever, ie by selecting the "e" and "g" arms and the length "f" of the rod 36. A mechanical-hydraulic system with a pressure regulator for maintaining a constant traction force according to any one of the preceding claims, characterized in that it is possible to select the force size (Fn) by varying the distances (e), (g) and (f) the force F is approximately linearly changing.