Crushing tool

Abstract

A gravel tool, comprising: a tool head (4), the tool head being supported by a guiding device (2) so as to be linearly displaceable relative to the guiding device between a retracted position and an extended position, and when the tool head is in its extended position, a distal end of the tool head extends from the guiding device to engage a surface to be broken; a driving device (5, 18, 20), the driving device being adapted to drive the tool head towards the retracted position of the tool head in a first operation and drive the tool head towards the extended position of the tool head in a second operation, the driving device including a driving member mounted on the guiding device (5, 20) and a driven member (18), the driven member being mounted on the tool head and being engaged by the driving member so as to be linearly displaceable relative to the guiding device when the driving member of the driving device operates; and a controller, the controller being adapted to control the operation of the driving device.

Description

Technical Field

[0001] The present invention relates to a rock-breaking tool, and more particularly to a rock-breaking tool with an improved design for reliable power supply. Background Art

[0002] When it is desired to break rocks, concrete or some other relatively hard materials, a rock-breaking tool is usually used as an attachment device for an excavator. Tools for such purposes usually have an impact device that is adapted to apply an impact to the tool head and thereby transmit the impact to the material to be broken. The impact device usually has a pneumatically or hydraulically driven impact piston that reciprocates and strikes an impact surface at the tip of the tool head. While the impact piston provides the impact, the tool head presses against the material to be broken and the tip of the tool head penetrates into the material to be broken under the influence of the impact device.

[0003] Generally, such rock-breaking tools are used in an upright orientation with the tool head extending from the lower end of the tool. The impact device forms a great vibration force for the rapid reciprocating motion of the tool head, and the vibration force as well as the broken rocks are transmitted to the excavator or other working machines to which the rock-breaking tool is attached, resulting in rapid wear of both the tool and its support structure and possibly injuring the operator. Due to the need to withstand the vibration force generated during the use of the tool, the rock-breaking tool is often heavy. In addition, the use of a pneumatically or hydraulically driven impact device also requires the supply of pressurized fluid using associated pipes and fittings that are prone to leakage.

[0004] The object of the present invention is to provide a rock-breaking tool that overcomes the foregoing problems of the prior art. Summary of the Invention

[0005] According to the present invention, there is provided a rock-breaking tool, which comprises: a tool head supported by a guiding device so as to be linearly displaceable relative to the guiding device between a retracted position and an extended position, when the tool head is in its extended position, the distal end of the tool head extends from the guiding device to engage the surface to be broken; a driving device adapted to drive the tool head towards the retracted position of the tool head in a first operation and towards the extended position of the tool head in a second operation, the driving device comprising a driving member mounted on the guiding device and a driven member mounted on the tool head and engaged by the driving member so as to be linearly displaceable relative to the guiding device when the driving member of the driving device operates; and a controller adapted to control the operation of the driving device.

[0006] Preferably, the driving device is electric. More preferably, the driving device includes an electric motor.

[0007] In a preferred embodiment, during the second operation and before the tool head reaches its extended position, the driven member of the drive means is separated from the driving member of the drive means.

[0008] The guiding means may be adapted to be arranged in use such that the tool head extends from the lower end of the guiding means when the tool head is in its extended position, and the tool head is capable of being displaced between its extended position and its retracted position along a vertical axis.

[0009] The guiding means may be adapted to be mounted on the arm of an excavator.

[0010] The guiding means may comprise a hollow tubular body, within which the tool head is capable of sliding axially, and when the tool head is in its extended position, the distal end of the tool head extends through an aperture in one end of the guiding means.

[0011] In one embodiment, the drive means may comprise a first rack mounted on the tool head, and the driving member of the drive means comprises a first motor-driven pinion mounted on the guiding means to be driven by a drive motor and adapted to be drivingly engaged with the first rack of the driven member to displace the tool head relative to the guiding means when the pinion rotates. Preferably, the drive motor comprises an electric motor operated under the control of the controller. The first rack may be arranged on the tool head such that the first pinion disengages from one end of the first rack when the tool head approaches its extended position, thereby separating the driving member of the drive means from the driven member of the drive means.

[0012] The drive means may further comprise: a second rack mounted on the tool head; and a second motor-driven pinion mounted on the guiding means and adapted to be driven by the drive motor and drivingly engaged with the second rack to displace the tool head between its extended position and its retracted position when the second pinion rotates in a first direction, the second pinion comprising a clutch adapted to disengage the pinion from the drive motor when the second pinion rotates in a second direction opposite to the first direction. The first pinion and the second pinion may be coaxially mounted on the output shaft of the drive motor, and the first rack and the second rack are mounted side by side and parallel to each other on one side of the tool head.

[0013] In an alternative embodiment, the first pinion may include a clutch under the control of the controller, whereby the clutch may be adapted to disengage the first pinion from the electric motor before the tool head reaches its extended position. It is contemplated that other types of drive means may be provided to move the tool head between its retracted and extended positions while disengaging the driven member of the drive means from the drive member as the tool head approaches its extended position.

[0014] Preferably, the distal end of the tool head terminates in a tip. The tip may be separable from the remainder of the tool head to allow replacement and / or exchange of the tip.

[0015] The guiding means may include shock-absorbing means, against which the tool head acts when the tool head reaches its extended position. Description of the Drawings

[0016] Embodiments of the tool according to the invention will now be described by way of example only with reference to the drawings, in which: -

[0017] Figure 1 is a perspective view of a tool according to an embodiment of the invention, in which the tool head is in its retracted or raised position;

[0018] Figure 2 is Figure 1 a longitudinal cross-section of the tool of, in which the tool head is in its extended position;

[0019] Figure 3 is Figure 1 a perspective cross-section of the tool of;

[0020] Figure 4 is Figure 1 a perspective view of the tool of, in which the tool head has been removed; and

[0021] Figure 5 is Figure 1 a detailed view of the lower end of the guiding tube of the tool of. Detailed Description of the Invention

[0022] As shown in the drawings, a tool for breaking rock or any other relatively hard material according to the invention includes an elongate hollow guiding tube 2, in which a tool head 4 is coaxially mounted, the tool head 4 being driven by a drive means, more preferably by an electric drive means (such as an electric motor 5), so as to be slidably movable along the length of the guiding tube 2 between Figure 1 the raised or retracted position shown in Figure 2 and the lowered or extended position shown in.

[0023] In the illustrated embodiment, the guide tube 2 is adapted to be mounted on the distal end of the arm of an excavator to be supported in a substantially vertical orientation via a suitable coupling. However, it is contemplated that the tool may be adapted to be mounted on any other type of support arrangement or device, or may be included as part of a particular rock-breaking vehicle or equipment.

[0024] The tool head 4 includes: a body portion 6 which is slidably mounted within the guide tube 2; and an elongate tool member 8 of the tool head 4 which extends from the lower end of the body portion 6 and terminates in a rock-breaking tip 10. When the tool head 4 is in its extended position, the elongate tool member 8 of the tool head 4 extends through an opening 12 in the end cap 14 of the guide tube 2 from the lower end of the guide tube 2. In a preferred embodiment, at least the tip 10 of the tool member 8 is detachable from the remainder of the tool head 4 to facilitate replacement of the tip 10 in case of wear or replacement of the tip 10 to suit the material to be broken.

[0025] The guide tube 2 may include a hollow column having a square cross-section, and the body portion 6 of the tool head 4 is slidably mounted within the guide tube 2. The body portion 6 of the tool head 4 is supported and guided for axial movement within the guide tube 2 via rollers 16 mounted on the side walls of the guide tube 2, thereby allowing the tool head 4 to freely slide within the guide tube 2 between its retracted position and its extended position. The rollers 16 may be spring-loaded against the inner wall of the guide tube 2.

[0026] In the embodiment shown in the drawings, the driven member of the drive means includes a first rack 18 mounted on at least one side of the body portion 6 of the tool head 4, and the driving member of the drive means includes a first pinion 20 which is mounted on the output shaft of an electric motor 5 which is mounted on the guide tube 2 such that the first pinion 20 is drivingly engaged with the first rack 18, the first pinion 20 being attached to the output shaft of the electric motor 5, whereby the motor 5 is adapted to operate under the control of a controller to rotate the first pinion 20 and thereby axially displace and rapidly accelerate the tool head 4 within the guide tube 2 from its retracted position towards its extended position, as will be described in more detail below.

[0027] The upper end of the first toothed track 18 terminates at a position spaced from the upper end of the body portion 6 of the tool head 4 such that the first pinion 20 disengages from the first rack 18 when the tool head 4 is near its extended position, thereby disengaging the tool head 4 from the drive means before the tool head 4 reaches its extended position, such that the tool head 4 is disengaged from the drive means before the tip 10 of the tool member 8 impacts the surface of the rock to be broken. Preferably, the first rack 20 and the first pinion 18 are arranged such that the first pinion 18 disengages from the first rack 20 when the tip 10 of the tool member 8 passes through the opening in the end cap 14 of the guide tube 2.

[0028] The second rack 22 is mounted parallel and side-by-side with the first rack 18 on at least one side of the main body portion 6 of the tool head 4. The second pinion 24 is mounted coaxially and side-by-side with the first pinion 24 on the output shaft of the motor 5 such that the second pinion 24 is drivingly engaged with the second rack 22.

[0029] The second rack extends substantially the full length of the tool head 4 such that the second pinion 24 remains engaged with the second rack 22 throughout the full range of movement of the tool head 4 between its retracted and extended positions.

[0030] The second pinion 24 is preferably mounted on the output shaft of the motor via a one-way coupling (such as a wedge or cam clutch) which is adapted to transmit rotational movement between the motor output shaft and the second pinion 24 in only one direction, particularly when operating the motor 5 to raise or retract the tool head 4 within the guide tube 2 between its extended and retracted positions.

[0031] Other types of drive means for driving the tool head 4 between its retracted and extended positions are conceivable, such as chains and sprockets, toothed belts and pulleys, recirculating ball screws or any other linear drive. Additionally, the drive means may include non-mechanical drives such as magnetic track motors (a plurality of coil pole pieces in the form of a linear motor) or solenoids. All of these techniques may be considered for expanding the technology to obtain greater or lesser impact energy.

[0032] As Figure 5 best shown, a shock absorber 26 may be mounted on the lower end of the guide tube 2 to absorb any shock between the tool head 4 and the end cap 14 of the guide tube 2 before the tool member 8 impacts the surface to be broken in the case where the tool head 4 reaches its fully extended position, thereby avoiding damage to the tool.

[0033] In a first operating phase, the controller operates the electric motor 5 to drive the second pinion 24 along the second rack 22 to thereby raise the tool head 4 along the guide tube 2 until the tool head 4 is in its fully retracted or raised position adjacent the upper end of the guide tube 2.

[0034] In a second phase, the controller operates the electric motor 5 to drive the first pinion 18 along the first rack 20 (the second pinion 22 rotates freely on the output shaft of the motor 5 due to the one-way coupling between the second pinion 22 and the output shaft), thereby rapidly accelerating the tool head 4 towards its extended position.

[0035] During the second operating phase, the tool head 4 continues to accelerate in the downward direction until it reaches a point where the first pinion 20 disengages from the upper end of the first rack 18, thereby separating the tool head 4 from the drive means. Due to inertia and under the influence of gravity, the tool head 4 continues on its downward trajectory towards its extended position until the tip 10 of the tool member 8 impacts on the surface to be broken up.

[0036] In the case where the tool head 4 reaches its fully extended position, the main body portion 6 of the tool head 4 engages with the end cap 14, and the shock absorber buffer 26 provided at the lower end of the guide tube 2 prevents damage to the tool due to the impact between the tool head 4 and the end cap 14 of the guide tube 2.

[0037] The cycle is then repeated.

[0038] The controller may include a microprocessor that is programmed to accurately control the operation of the electric motor to accurately control the movement of the tool head, thereby optimizing the rock-breaking action of the tool head while minimizing the vibration and impact force transmitted to the components of the tool and its support structure, thus allowing the weight and size of the rock-breaking tool to be greatly reduced compared to prior art devices. Operating the drive means using electricity avoids the problems associated with using pneumatic or hydraulic drives and enables the rock-breaking tool to be used in a wide variety of different applications.

[0039] The present invention is not limited to the embodiments described herein, but may be amended or modified without departing from the scope of the invention as defined by the appended claims.

Claims

1. A gravel-breaking tool, the gravel-breaking tool comprises: a tool head (4), the tool head being supported by a guiding device (2) so as to be linearly displaceable relative to the guiding device (2) between a retracted position and an extended position, and when the tool head (4) is in its extended position, the distal end of the tool head (4) extends from the guiding device (2) to engage the surface to be broken; a driving device, the driving device being engaged with the tool head and adapted to drive the tool head towards the retracted position of the tool head in a first operation and drive the tool head (4) towards the extended position of the tool head in a first part of a second operation, the driving device comprising a driving member mounted on the guiding device and a driven member, the driven member being mounted on the tool head and being engaged by the driving member so as to be linearly displaceable relative to the guiding device when the driving member of the driving device operates; and a controller, the controller being adapted to control the operation of the driving device, wherein the driving device is electric; and wherein during a second part after the first part of the second operation, when the tool head approaches its extended position, the driven member of the driving device is separated from the driving member of the driving device.

2. The tool according to claim 1, wherein the guiding device (2) is adapted to be arranged in use such that when the tool head (4) is in its extended position, the tool head extends from the lower end of the guiding device (2), and the tool head is displaceable between its extended position and its retracted position along a vertical axis.

3. The tool according to claim 2, wherein the guiding device is adapted to be mounted on the arm of an excavator.

4. The tool according to claim 1, wherein the guiding device (2) comprises a hollow tubular body, the tool head (4) being axially slidable within the hollow tubular body, and when the tool head is in its extended position, the distal end of the tool head (4) extends through a hole (12) in one end (14) of the guiding device (2).

5. The tool according to any one of claims 1-4, wherein the driving device comprises a first rack (18) mounted on the tool head (4), the driving member of the driving device comprises a first pinion (20), the first pinion being mounted on the guiding device (2) to be driven by an electric drive motor (5) and adapted to be drivingly engaged with the first rack (18) of the driven member so as to displace the tool head (4) relative to the guiding device when the first pinion (20) rotates.

6. The tool according to claim 5, wherein the first rack (18) comprises a clutch, the clutch being under the control of the controller, whereby the clutch is adapted to separate the first rack (18) from the electric drive motor (5) before the tool head reaches its extended position.

7. The tool according to claim 5, wherein the first rack (18) is arranged on the tool head (4) such that when the tool head (4) approaches its extended position, the first pinion (20) disengages from one end of the first rack (18), thereby separating the driving member of the driving device from the driven member of the driving device.

8. The tool according to claim 5, wherein the driving device further comprises: a second rack (22), which is mounted on the tool head (4); and a second pinion (24), which is mounted on the guiding device (2) and is adapted to be driven by the electric drive motor (5) and drivingly engaged with the second rack (22) to shift the tool head (4) between its extended position and its retracted position when the second pinion (24) rotates in a first direction, the second pinion (24) comprising a clutch which is adapted to disengage the second pinion (24) from the electric drive motor (5) when the second pinion (24) rotates in a second direction, the second direction being opposite to the first direction.

9. The tool according to claim 8, wherein the first pinion (20) and the second pinion (24) are coaxially mounted on the output shaft of the electric drive motor (5), and the first rack (20) and the second rack (22) are mounted side by side and parallel to each other on one side of the tool head (4).

10. The tool according to any one of claims 1-4, wherein the distal end of the tool head (4) terminates in a tip (10).

11. The tool according to claim 10, wherein the tip (10) is separable from the remainder of the tool head (4) to allow replacement and / or exchange of the tip (10).

12. The tool according to any one of claims 1-4, wherein the guiding device (2) comprises a shock-absorbing device (26) on which the tool head acts when the tool head (4) reaches its extended position.

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