CN1261940A - Impact compactor - Google Patents

Abstract

The invention concerns an impact compactor (10) which comprises one or more out-of-round compactor masses (14). The masses are moved rotationally over a soil surface, at an angular velocity suitable for normal operation, to apply periodic compaction blows to the soil surface. This is achieved by primary drive means. In the case of a towed impact compactor, the primary drive means is typically a tractor. The impact compactor (10) includes an auxiliary drive which is arranged to operate automatically, in response to a reduction of the angular velocity of the compactor masses below the angular velocity suitable for normal operation, to apply an auxiliary rotary drive that restores their angular velocity.

Description

impact compactor

The invention relates to an impact compactor.

The term "impact compactor" means a soil compacting machine which incorporates a rotating non-circular weight which, as it is pulled or otherwise driven across the surface of the soil, It produces a series of impact blows on the soil surface. The weight of an impact compactor has many sides that form a series of spaced apart raised points on the surrounding surface of the weight, each raised point followed by a compacting surface. As the weight is pulled or otherwise driven across the soil surface, it rises at each bump and then, after passing the bump, falls forward and downward, with the result that the following The compacting surface then delivers an impact blow to the soil surface. So the action of the weight is to store energy each time it rises over the bump, and then release this energy in a percussive strike.

It has been found that in practice the impact compactor described above works very well and can compact the soil very well, even at great depths below the soil surface. However, in some cases, problems may be encountered where the nubs poke or slide across the soil surface, and as a result, the rotational speed of the compacting weight is reduced below normal speed, increasing the forward motion of the impact compactor resistance. This problem is exacerbated when the impact compactor is equipped with a rear screed to level the compacted soil, since the inclusion of a screed increases the resistance to forward motion of the impact compactor.

According to the present invention there is provided an impact compactor comprising at least one non-circular compacting weight which, in use, is driven by a main drive to rotate over the soil surface at an angular velocity suitable for normal Operated to apply periodic impact blows to the surface of the soil, said impact compactor also has an auxiliary drive designed to operate automatically, which is able to operate between said compacting weights (or each compacting weight) Responding when the angular velocity is lower than the angular velocity suitable for normal operation, an auxiliary rotational driving force is applied to the (each) compaction weight to bring it back to the angular velocity suitable for normal operation.

While other types of auxiliary drives are within the scope of the present invention, the preferred auxiliary drive comprises a hydrostatic drive powered by the main drive and control means capable of controlling the angular velocity of the compacting weight Reacting to the angular velocity of the ground-contacting driven wheel of the main drive unit to control the operation of the above-mentioned hydrostatic drive unit. This hydrostatic driving device is preferably a hydraulic motor powered by a hydraulic pump. When in use, the above-mentioned hydraulic pump is driven by the main drive device, and the above-mentioned hydraulic motor drives the above-mentioned (each) hydraulic motor through a chain drive. real weight. In this configuration, the above-mentioned control means may comprise a proportional valve between the sensor and its associated electronics sensitive to the angular velocity of the compacting weight and the driven wheel of the main drive in contact with the ground. Regulates the flow of hydraulic fluid from the hydraulic pump to the hydraulic motor under the control of the hydraulic pump.

The invention also extends to a dual compaction weight impact compactor comprising a pair of spaced apart compaction weights rigidly mounted on a common shaft for synchronous rotation. In this example, the above-mentioned compacting weights are generally mounted on hubs at both ends of the above-mentioned common shaft, and the above-mentioned chain transmission device includes a first sprocket wheel driven by the above-mentioned hydraulic motor, and a chain wheel around the above-mentioned first sprocket wheel. and a chain of a second sprocket secured to an auxiliary shaft, and means for driving said hub off said auxiliary shaft. Such means preferably include a third sprocket fixed to the auxiliary shaft engaging a fourth sprocket fixed to said hub.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the attached picture:

Fig. 1 shows a perspective view of the chain drive of an auxiliary drive of an impact compactor according to the present invention and the parts cooperating with it, but, for the sake of clarity, the chain itself is omitted among the figures;

Fig. 2 represents the partial schematic plan view of the chain transmission device in Fig. 1 and the parts that cooperate with it;

Figure 3 shows a partial schematic side view of the chain drive in Figure 1 and its cooperating parts;

Fig. 4 schematically shows an impact compactor equipped with the chain drive shown in the above figures and the parts cooperating with it.

FIG. 4 schematically shows an impact compactor 10 according to the invention. In this example, the impact compactor 10 is towed by a main propulsion machine, i.e. a tractor 12, but it should be understood that the invention can also be used in self-propelled impact compactors which themselves have a main propulsion machine. machine.

In the present embodiment, impact compactor 10 includes a pair of three-sided compacting weights 14 of general construction. The weights 14 are rigidly mounted on a common shaft 16 which forms part of a tube shaft assembly 18 as viewed in the plane of FIG. 2 . As shown in FIG. 2, the tube axle assembly 18 includes a tube 20 to which a tie rod 26 is attached. As shown schematically in FIG. 4 , the tie rod 26 is connected by a suspension rod 28 ( FIG. 4 ) to a wheeled vehicle frame 30 which is hung on the tractor 12 .

Those skilled in the art of impact compactor technology will appreciate that the structure of the traction impact compactor 10 described above is known. Also, it will be appreciated that the traction assembly, including tie rods and booms, is resilient so as to absorb shock loads when compacted weights are drawn across the soil surface and impacted by impact. To understand the further details of the traction assembly of this compacted weight in detail, you can refer to the disclosed content in the patent document WO 94/26985.

The unusual construction of the impact compactor 10 is that it has an auxiliary drive. This device comprises a variable displacement hydraulic motor 32 mounted on a mounting plate 33 connected to the above-mentioned tie rod 26, and a chain drive schematically indicated at 35 in FIG. 4 . Referring to FIGS. 1-3 for more detail, the chain drive includes a sprocket 34 mounted on the output shaft of a motor 32 . A chain 36 , schematically indicated by a dotted line in FIGS. 2 and 3 , is wound around sprocket 34 and also around sprocket 38 mounted on shaft 40 . Shaft 40 is above and parallel to shaft 16 and is supported by inner and outer bearings 42 and 44 mounted on tube 20 of tube shaft assembly 18 .

Sprockets 46 are mounted on both ends of the shaft 40 . The other chain 47 passes around the sprockets 46 and 48 mounted on the hub 50 on which the compacting weight 14 is mounted. For clarity, the weight 14 has been omitted from Figures 1-3. Chain drive 35 also includes chain tensioners 52, 53 and 54 and an idler sprocket assembly 56 to maintain chains 36 and 47 under proper tension.

Referring again to Fig. 4, reference numeral 58 represents the engine of the tractor, and reference numeral 60 represents its transmission. The driven wheels of the tractor are indicated by reference numeral 62 .

A conventional swash plate variable displacement hydraulic pump 64 is driven by transmission 60 . Pump 64 supplies hydraulic fluid to motor 32 under the control of a proportional valve connected to a sensor and cooperating with an electronic controller sensitive to the rotational speed (ie, angular velocity) of weight 14 and driven wheel 62 . During normal operation, hydraulic fluid is continuously pumped into motor 32 by pump 64 . If the sensor detects a rotational speed mismatch between the compacting weight and the driven wheel 62, i.e., the wheel is turning faster than the compacting weight, the valve 66 increases the flow to the motor 32 under the control of the electronic controller. flow of hydraulic fluid. The above-mentioned hydraulic motor 32 exerts additional torque on the compacted weight correspondingly through the chain transmission mechanism, and makes it rotate at an accelerated speed, so that its rotational speed has just caught up with the rotational speed of the wheel 62 .

For example, if a compacting weight pokes into the soil surface or slides relative to the soil surface, instead of rotating around the next bump indicated by reference numeral 68 in Figure 4, or, if A speed mismatch may occur where the action of the schematically indicated tail screed increases excessively the resistance to forward motion of the impact compactor.

As soon as the two speeds are re-matched, valve 66 reduces the hydraulic fluid supply to motor 32 to the normal level and normal advance of the compacting weight resumes.

Thus, it will be appreciated that the impact compactor 10 described above has a hydrostatic drive control that automatically provides additional rotational power to the compacting weight in the event of a speed mismatch.

Sprocket 38 is mounted on shaft 40 via a one-way clutch 72 which transmits rotational motion in one direction only and acts as an idler in the other direction.

Due to this feature, it is also impossible for the compacted weight to drive the tractor in case the rotational speed of the compacted weight exceeds the speed of the wheels 62 . This can happen, for example, when compacting weights fall downwards after passing over bumps.

In the above description, the auxiliary drive is of a hydrostatic nature. However, it should be understood that the concept of the present invention is equally applicable to other types of auxiliary drive devices, including purely mechanical or electro-mechanical devices. The above-mentioned chain transmission device can also be replaced by any other suitable device, for example, an independent hydraulic transmission device can be used on the hub of the compacted weight. It should also be pointed out that the invention is not limited to the range of applications for traction compacting weights, but it can equally be applied to self-propelled impact compactors equipped with their own main propellers.

Claims (9)

1. An impact compactor comprising at least one non-circular compacting weight which, in use, is driven by a main drive to rotate over the soil surface at an angular velocity suitable for normal operation so as to Periodic impact blows are applied to the surface of the soil, and said impact compactors also have auxiliary drives designed to operate automatically at angular velocities of said or each compacting weight lower than those appropriate for normal In response to the angular velocity of the work, an auxiliary rotational driving force is applied to the above-mentioned (each) compacting weight to restore it to an angular velocity suitable for normal operation. 2. The impact compactor of claim 1, wherein said auxiliary drive means comprises a hydrostatic drive powered by the main drive means and a control means, said control means capable of controlling the compacted weight The angular velocity of the main driving device and the angular velocity of the driven wheel in contact with the ground of the main driving device react to control the work of the above-mentioned hydrostatic driving device. 3. The impact compactor according to claim 2, wherein the above-mentioned hydrostatic driving device comprises a hydraulic motor powered by a hydraulic pump, and when in use, the above-mentioned hydraulic pump is driven by the main driving device, And above-mentioned hydraulic motor then drives above-mentioned (each) compaction weight through chain drive. 4. The impact compactor as claimed in claim 3, characterized in that said control device comprises a proportional valve, and this proportional valve is connected between the sensor and its cooperating, angular velocity of the compacting weight and the main driving device. The flow of hydraulic fluid from the hydraulic pump to the hydraulic motor is regulated under the control of angular velocity sensitive electronics of driven wheels in contact with the ground. 5. The impact compactor of claim 3 or 4, further comprising a pair of spaced apart compacting weights rigidly mounted on a common shaft for synchronous rotation. 6. The impact compactor according to claim 5, wherein said compacting weights are mounted on hubs at both ends of said common shaft, and said chain drive comprises a first sprockets, a chain surrounding said first sprocket and a second sprocket secured to an auxiliary shaft, and means for driving said hub off said auxiliary shaft. 7. The impact compactor of claim 6, wherein said means for driving the hub away from the auxiliary shaft comprises a first sprocket fixed on the auxiliary shaft and engaged with a fourth sprocket fixed on the hub. Three sprockets. 8. The impact compactor according to any one of claims 1-7, wherein the impact compactor is hung on a tractor used as the main driving device when in use 9. The impact compactor according to any one of claims 1-7, characterized in that said impact compactor is also equipped with its own main drive.

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