Steel wire rope pre-tightening device and crane

Abstract

The utility model discloses a steel wire rope pre-tightening device and a crane, which comprise two transmission shafts arranged in parallel at an interval, bearing seats are arranged at two ends of each transmission shaft, the transmission shafts are fixed on a fixed support through the bearing seats, friction pulleys are sleeved on the transmission shafts, and a steel wire rope is sequentially and alternately wound on the two friction pulleys. The ends of the two transmission shafts are connected with brake clutches, reaction torque is provided through the brake clutches, and the steel wire rope is pre-tightened. By utilizing reaction torque provided by the clutch and friction force between the pulley block and the steel wire rope, the steel wire rope is wound on the winding drum in a loaded mode, and the purpose of pre-tightening the steel wire rope is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of cranes, in particular to a wire rope pre-tightening device and a crane. Background Art

[0002] At present, the drums used for cranes are basically double-folded drums, and the wire ropes are wound in layers. It is important that the wire rope on the drum (the lower wire rope at the lifting position) should be wound under the specified preload to avoid the inner wire rope from being loosened, which is squeezed or twisted by the outer wire rope to cause the wire rope to be disordered; in order to avoid the wire rope from "jumping", "going off the track", "uneven winding" and other disorderly rope phenomena, the wire rope must maintain sufficient preload so that the wire rope can always be close to the surface of the rope groove. The preload acting on the wire rope on the drum (the lower wire rope at the lifting position) should not be less than 2% of the breaking load of the wire rope (or 10% of the working load). The wire rope needs to be wound on the drum and various methods need to be used to preload the wire rope. Only then can it be hoisted normally and safely.

[0003] like Figure 1 As shown in the figure, in general lifting operations, the crane must release most of the wire rope on the drum before the unloaded hook can be dropped to the ground. In subsequent lifting operations, as the load is increased, the wire rope is wound back onto the drum under tension. When used alone for high-altitude disassembly or shield lifting, on the contrary, it is required to lift the unloaded hook to the maximum height and lift the heavy objects to be disassembled to the ground. At this time, the wire rope is wound around the drum without sufficient pre-tightening force, resulting in loose winding of the wire rope. At this time, under the action of tension, the wire rope will cut into the lower layer of wound wire ropes. Since the wire rope wound around the drum is in a loose state, it has no strength to withstand the pressure of tightening the wire rope. When the tensile wire rope cuts in, the wire rope wound around the outer layer will be damaged, which will cause the lifting movement to stop abruptly. The resulting impact is enough to overturn the crane. Summary of the invention

[0004] Purpose of the utility model: In order to overcome the shortcomings of the background technology, the first purpose of the utility model is to disclose a wire rope pretensioning device;

[0005] The second object is to disclose a crane comprising the above-mentioned wire rope pretensioning device.

[0006] Technical solution: The wire rope pretensioning device disclosed in the utility model comprises two transmission shafts arranged in parallel and at intervals, bearing seats are arranged at both ends of the transmission shafts and are fixed to a fixed bracket through the bearing seats, friction pulleys are sleeved on the transmission shafts, and the wire rope is alternately wound around the two friction pulleys in sequence, and the ends of the two transmission shafts are connected to braking clutches, which provide reverse torque through the braking clutches to achieve wire rope pretensioning.

[0007] Furthermore, the two transmission shafts and the friction pulley have exactly the same structure.

[0008] Furthermore, the friction pulley is connected to the transmission shaft via a flat key or a spline.

[0009] Furthermore, the brake clutch is arranged at the same end of the two transmission shafts and is fixed via a clutch mounting seat and a fixing bracket.

[0010] Furthermore, the brake clutch is connected to a proportional control valve group, and the proportional control valve group includes an oil inlet filter and an electric proportional pressure reducing valve.

[0011] A crane comprises the above-mentioned wire rope pre-tensioning device.

[0012] Furthermore, the wire rope pre-tensioning device is installed on the crane boom through a fixed bracket, and the wire rope passes through the wire rope pre-tensioning device and is then connected to the hook through a pulley block at the boom end.

[0013] Beneficial effect: Compared with the prior art, the utility model utilizes the counter-torque provided by the clutch and the friction between the pulley block and the wire rope to make the wire rope with load be wound onto the drum, thereby achieving the purpose of pre-tightening the wire rope; this pre-tightening method occupies little space, and the wire rope can be pre-tightened at any time regardless of the working conditions, site, and environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of a lifting system in the prior art;

[0015] Figure 2 This is a cross-sectional view of the wire rope pretensioning device of the utility model;

[0016] Figure 3 This is a schematic diagram of the winding of the steel wire rope of the utility model;

[0017] Figure 4 It is a schematic diagram of a lifting system including a wire rope pre-tensioning device;

[0018] Figure 5 This is a connection diagram of the proportional control valve group of the utility model. DETAILED DESCRIPTION

[0019] The technical solution of the utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0020] like Figure 2 The wire rope pretensioning device shown includes two transmission shafts 1 arranged in parallel and at intervals. Bearing seats 2 are arranged at both ends of the transmission shaft 1 and are fixed to a fixed bracket 3 through the bearing seats 2. A friction pulley 4 is sleeved on the transmission shaft 1, and the friction pulley 4 is connected to the transmission shaft 1 through a flat key or a spline. The two transmission shafts 1 and the friction pulley 4 have exactly the same structure.

[0021] like Figure 3 As shown, the steel wire rope 5 is alternately wound around the two friction pulleys 4 in sequence, and the ends of the two transmission shafts 1 are connected to the brake clutch 6, which is arranged at the same end of the two transmission shafts 1 and fixed to the fixed bracket 3 through the clutch mounting seat 7. By adjusting the brake clutch pressure difference, the brake clutch 6 provides a counter torque to realize the pre-tightening of the steel wire rope 5. When the brake clutch is fully opened, the counter torque is zero, and no pre-tightening force is provided.

[0022] like Figure 5 As shown, the brake clutch 6 is connected to a proportional control valve group 8, and the proportional control valve group 8 includes an oil inlet filter and an electric proportional pressure reducing valve. The control current range of the electric proportional pressure reducing valve is 200-750mA, the working pressure is 35bar, and the filter specification is 100μm;

[0023] During operation, if the wire rope does not need to be pre-tightened, the given pressure at the P port is 35 bar, the given control current value of the electric proportional control valve group P10 is 750 mA, the reducer brake is fully opened, the reverse torque is zero, and no pre-tightening force is provided;

[0024] During operation, if it is necessary to pre-tighten the wire rope, the given pressure at the P port is 35 bar. The given control current value of P10 can be adjusted to control the pressure after passing through the proportional pressure reducing valve to achieve different pre-tightening forces. As a result, the wire rope generates tension under the action of the clutch counter-torque and the friction force of the pulley to pull the pulley group in the pre-tightening device to rotate, so that the wire rope is loaded onto the drum to achieve the pre-tightening effect of the wire rope.

[0025] like Figure 4 As shown, the wire rope pre-tensioning device is installed on the crane boom, the wire rope 5 is wound on the pulley of the pre-tensioning device, and then connected to the hook 10 through the pulley block 9 at the arm end. When the wire rope needs to be pre-tightened, the lifting mechanism releases the wire rope under the empty hook condition. At this time, when the brake clutch in the pre-tightening device is fully opened, the counter-torque is zero, and no pre-tightening force is provided; after the wire rope is released, the lifting mechanism rotates to collect the rope. At this time, according to the pre-tightening force required for the wire rope, the pressure difference of the brake clutch is adjusted, and the brake clutch provides counter-torque. The wire rope generates tension under the action of the clutch counter-torque and the friction force of the pulley to pull the pulley block in the pre-tightening device to rotate, so that the wire rope is loaded onto the drum, thereby realizing the pre-tightening effect of the wire rope.

Claims

1. A wire rope pretensioning device, characterized in that: The invention comprises two transmission shafts (1) arranged in parallel and spaced apart, bearing seats (2) being arranged at both ends of the transmission shafts (1) and being fixed to a fixed bracket (3) through the bearing seats (2), a friction pulley (4) being sleeved on the transmission shaft (1), a steel wire rope (5) being alternately wound around the two friction pulleys (4) in sequence, and the ends of the two transmission shafts (1) being connected to a brake clutch (6), and a counter torque is provided by the brake clutch (6) to realize pre-tightening of the steel wire rope (5).

2. The wire rope pretensioning device according to claim 1, characterized in that: The two transmission shafts (1) and the friction pulley (4) have exactly the same structure.

3. The wire rope pretensioning device according to claim 1, characterized in that: The friction pulley (4) is connected to the transmission shaft (1) via a flat key or a spline.

4. The wire rope pretensioning device according to claim 1, characterized in that: The brake clutch (6) is arranged at the same end of the two transmission shafts (1) and is fixed to the fixing bracket (3) via a clutch mounting seat (7).

5. The wire rope pretensioning device according to claim 1, characterized in that: The brake clutch (6) is connected to a proportional control valve group (8), and the proportional control valve group (8) comprises an oil inlet filter and an electric proportional pressure reducing valve.

6. A crane comprising the wire rope pretensioning device according to claim 1.

7. The crane according to claim 6, characterized in that: The wire rope pre-tensioning device is installed on the crane boom via a fixed bracket (3); the wire rope (5) passes through the wire rope pre-tensioning device and is then connected to the hook (10) via a pulley block (9) at the boom end.

Images