The present disclosure relates to a power tool.

Background

Hydraulic breakers for cutting masonry are well known. Typically they incorporate a weight which is raised against gravity by using hydraulics. The weight is driven into an accumulator and the combination of hydraulics and the accumulator are used to drive the weight against a drill bit delivering an impact force to a masonry target.

A common problem with most breakers is the amount of vibration generated during operation of the device. This is a problem whether the device is operated by hand or supported by another vehicle (for example a backhoe loader). Not only is the vibration damaging to the user and/or vehicle, but also creates a great deal of noise pollution, which is disruptive and unwelcome for anyone in the immediate vicinity.

Additionally, during misfire (e.g. when the drill bit is not loaded against a target, for example because the target has broken or because the breaker has been operated when lifted free of a target) the rebound of the drill bit can cause significant shock loads in the housing of the breaker, potentially resulting in failure.

Another problem with conventional breakers is that the amount of energy of the impact force per impact is unknown or misquoted. Hence a user may operate the breaker essentially in ignorance of whether the output from the breaker will be sufficient to break the target object. Hence a breaking operation may take longer than expected or have to be aborted if the device is adequate (for example if the target is very hard).

Additionally, the power output of conventional breakers is substantially fixed, with significant alterations or maintenance required to improve the blow energy or to repair a device where the blow energy has diminished.

Hence a power tool which absorbs vibrations to reduce the impact on a user or supporting frame/equipment, as well as reducing operational noise, whose power output can be determined so that a user knows that the device is operating correctly, and hence only needs to stay on station performing the breaking activity for the expected time and which is operable to alter the blow energy to the drill bit, is highly desirable.

Summary

According to the present disclosure there is provided apparatus and method as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

Accordingly there may be provided a power tool (10) having an operational axis (12), the power tool (10) comprising: a tool carrier (100) for mounting an impact tool (102), the tool carrier (100) comprising a base member (104) aligned with the operational axis (12), and operable to move along the operational axis (12) in a first direction (D1) to an extended position; and operable to move along the operational axis (12) in a second direction (D2) towards a tool carrier retracted position to receive impact energy; the base member (104) having : a head end (110) for receiving the impact energy from the second direction along the operational axis (12); a foot end (112) at an opposite end of the tool carrier (100) to the head end (110), the foot end (112) being provided with a tool mount (114) configured to hold a tool (102); a first damper (200) provided to decelerate the tool carrier (100) in the first direction (D1) along the operational axis (12) to bring it to a stop in the tool carrier extended position; and a second damper (300) provided to decelerate the tool carrier (100) in the second direction (D2) along the operational axis (12) to bring it to a stop at the tool carrier retracted position.

The power tool may further comprise a support plate (400) provided with an aperture (402) through which the tool carrier (100) extends; the tool carrier (100) comprising a first damper retaining feature (210) provided between the head end (110) and the support plate (400), the first damper (200) provided between the first damper retaining feature (210) and the support plate (400).

The tool carrier (100) may comprise a second damper retaining feature (310) provided between the foot end (112) and the support plate (400), the second damper (300) provided between the second damper retaining feature (310) and the support plate (400). The tool carrier (100) may comprise a second damper retaining feature (310) provided between the foot end (112) and the support plate (400), and the second damper (300) may be provided between the second damper retaining feature (310) and a support land (660), the support land (660) extending from the housing assembly (600), and the support land (660) being spaced apart from the support plate (400) along the operational axis (12).

The second damper retaining feature (310) may be spaced apart from the support plate (400) along the operational axis (12).

The support plate (400) and the support land (660) may each form a different part of the housing assembly (600).

The first damper retaining feature (210) may comprise a first damper support land (212) which is coupled to, and extends radially from, the tool carrier (100) to prevent the first damper (200) from moving past the first damper support land (212) in the second direction (D2); and the second damper retaining feature (310) may comprise a second damper support land (312) which is coupled to, and extends radially from, the tool carrier (100) to prevent the second damper (300) from moving past the second damper support land (312) in the first direction (D1).

The first damper (200) may comprise a first damping member (214) which extends around the tool carrier (100); and/or the second damper (300) may comprise a second damping member (314) which extends around the tool carrier (100).

The first damper (200) may comprise at least two first damping members (214) in series along the operational axis (12), wherein the at least two first damping members (214) have a different stiffness and/or shore hardness to one another, or the same stiffness and/or shore hardness as one another; and/or the second damper (300) may comprise at least two second damping members (314) in series along the operational axis (12); wherein the at least two second damping members (314) have a different stiffness and/or shore hardness to one another, or the same stiffness and/or shore hardness as one another.

The first damper (200) and/or second damper (300) may travel with the tool carrier (100) along the operational axis (12). The first damper (200) and/or second damper (300) may be fixed relative to the support plate (400) such that the tool carrier (100) is moveable relative to the first damper (200) and/or second damper (300) along the operational axis (12).

The first damper (200) and/or second damper (300) may be fixed relative to the housing assembly (600) such that the tool carrier (100) is moveable relative to the first damper (200) and/or second damper (300) along the operational axis (12).

The first damper (200) may be fixed relative to the support plate (400) and the second damper may be fixed relative to the support land (660) such that the tool carrier (100) is moveable relative to the first damper (200) and/or second damper (300) along the operational axis (12).

The base member (104) of the tool carrier (100) may comprise a first section (130) which extends from the head end (110) towards the foot end (112) with a constant diameter along its length to a second section (132); wherein the second section (132) extends from the first section (130) towards the foot end (112) with an increasing diameter to a third section (134); wherein the third section (134) extends, with a constant diameter, from the second section (132) towards a fourth section (136) at the foot end (112); wherein the fourth section (136) defines the foot end (112) and tool mount (114).

The tool mount (114) may comprise a tool coupling land (150) which extends a right angles to the operational axis (12); and the tool (102) may comprise a tool carrier coupling land (156) complementary in shape with, and configured to engage with, the tool coupling land (150); the engagement land (150) comprising a first location feature (152) configured to couple with a second location feature (154) on the tool (102).

The tool (102) may be provided as a wear plate (160) which is configured to cover the foot end (112) of the tool carrier (100).

The wear plate (160) may define a free surface (162) for striking a target object, the free surface (162) being convex, flat or provided as a chisel. The third section (134) may define engagement lands (140) provided as flat regions; and the power tool (10) may further comprise a tool carrier engagement feature (500) complementary in shape to, and for engagement with, the tool carrier engagement lands (140) to thereby prevent rotation of the tool carrier (100) around the operational axis (12), and permit relative movement of the tool carrier (100) along the operational axis (12).

The housing assembly (600) may comprise a wall (632) which defines a chamber (636) through which the base member (104) of the tool carrier (100) extends. The wall (632) may define a first groove (638). The base member (104) may define a second groove (106). A key member (108) may be located in, and extend between, the first groove (636) and the second groove (106) to thereby prevent rotation of the tool carrier (100) relative to the wall (632), and prevent rotation of the tool carrier (100) around the operational axis (12).

The power tool (10) may further comprise a body (700) comprising a first flange (702) having a first engagement land (706) and a first engagement edge (704); an actuator (800) for moving the body (700) along the operational axis (12): from an impact position at which the body (700) is operable to transfer impact energy to the head end (110) of the tool carrier (100) to a body retracted position spaced apart from the impact position along the operational axis (12); the actuator (800) comprising : a first actuator rotational axis (802), and a first engagement member (804) offset from, and rotatable around, the first actuator rotational axis (802), the first engagement member (804) and first flange (702) arranged relative to each such that : at the impact position the first engagement member (804) is operable to engage with the first flange engagement edge (704), and as the first engagement member (804) rotates around the first actuator rotational axis (802), the first engagement member (804): travels along the first flange (702) engagement land (706); and simultaneously urges the body (700) in a direction away from the body (700) impact position towards the body retracted position; and the body (700) is operable to travel along the operational axis (12) between the impact position; and a rest position spaced apart from the impact position; wherein at the rest position the first engagement member (804) is engaged with the edge (704) of the first flange (702).

At the body retracted position the first engagement member (804) may be operable to move past the first flange engagement edge (704) to thereby disengage the body (700) from the first engagement member (804), thereby permitting the body (700) to move on an impact stroke to the impact position.

The first actuator rotational axis (802) may be perpendicular to the operational axis (12); and the first flange engagement edge (704) is parallel with the first actuator rotational axis (802).

The first flange (702) may extend away from the first flange engagement edge (704) in a direction away from the first actuator rotational axis (802) and perpendicular to the operational axis 12.

The power tool (10) may further comprise a housing assembly (600) which defines a cavity (602) in which the tool carrier (100) is located; wherein the housing assembly (600) defines an opening (604) through which the tool member (100) extends such that the head end (110) of the tool carrier (100) is located inside the cavity (602) and the foot end (112) is located outside of the cavity (602).

There may be provided a method of applying a percussive force to an object, using a power tool (10) according to the present disclosure.

There may be provided a power tool (10) having an operational axis (12), wherein the power tool (10) may comprise: a tool carrier (100) for mounting an impact tool (102), the tool carrier (100) having a head end (110) and a foot end (112) at an opposite end of the tool carrier (100) to the head end (110); a body (700) constrained to move along the operational axis (12) from an impact position at which the body (700) is operable to transfer impact energy to the head end (110) of the tool carrier (100) to a body retracted position spaced apart from the impact position along the operational axis (12); a housing assembly (600) which defines a cavity (602) in which the body (700) and tool carrier (100) are located; an elastic rope (1000), a first end (1002) of the elastic rope (1000) being coupled to the body (700), and a second end (1004) of each of the elastic rope (1000) being coupled to the housing assembly (600) via an anchor system (900); the tension in the elastic rope (1000) having a first value (T1) when the body is in the body retracted position and having a second value (T2) with the body (700) is in the impact position; wherein the anchor system (900) may be operable to alter the position of the second end (1004) of the rope (1000) relative to the first end (1002) in a direction along the operational axis (12) to thereby adjust the first tension value (T1) at the body retracted position and thereby adjust the second tension value (T2) at the impact position.

The elastic rope (1000) may be one of an array of elastic ropes (1000), the first end (1002) of each of the ropes of the array of elastic ropes (1000) being coupled to the body (700), and the second end (1004) of each of the elastic ropes (1000) being coupled to the housing assembly (600) via an anchor system (900); the tension in each of the elastic ropes (1000) having a first value (T1) when the body is in the body retracted position and having a second value (T2) with the body (700) is in the impact position; wherein the anchor system (900) may be operable to alter the position of the second end (1004) of each of the ropes (1000) relative to the first end (1002) in a direction along the operational axis (12) to thereby adjust the first tension value (T 1) at the body retracted position and thereby adjust the second tension value (T2) at the impact position.

For each rope (1000), the distance between the first end (1002) and the second end (1004) at the impact position may be greater than the un-extended length of each rope (1000), such that at the impact position each rope is held in tension.

The anchor system (900) may comprise: a rope tensioning ring (902) which is centred on, and extends around, the operational axis (12); the second end (1004) of the ropes (1000) being coupled to the rope tensioning ring (902); the rope tensioning ring (902) being moveable along the operational axis (12) in the first direction (D1) and second direction (D2) to thereby alter the position of the second end (1004) of each of the ropes (1000) relative to the first end (1002) in a direction along the operational axis (12).

The power tool (10) may further comprise a tensioning member (410) mounted to the housing assembly (600) and coupled to the rope tensioning ring (902), the tensioning member (410) being operable to move the rope tensioning ring (902) along the operational axis (12) in the first direction (D1) and/or move the rope tensioning ring in the second direction (D2).

The rope tensioning ring (902) may define a threaded aperture (920) through which the tensioning member (410) extends. The tensioning member (410) may be provided with a thread (414) compatible with the thread (922) of the aperture (920) to thereby couple the tensioning member (410) and rope tensioning ring (902) together. The tensioning member (410) may be rotatable relative to the rope tensioning ring (902) such that rotation of the tensioning member (410) causes the rope tensioning ring (902) to move along the tensioning member (410) to thereby move the rope tensioning ring (902) along the operational axis (12) in the first direction (D1) and/or move the rope tensioning ring in the second direction (D2).

The tensioning member (410) may extend to a free end (924), the free end (924) provided with an engagement feature (926) for engagement with a tool for rotating the tensioning member (410).

The power tool (10) may further comprise an actuator system (904) mounted to the housing assembly (600) and extending to the rope tensioning ring (902), the actuator system (904) operable to move the rope tensioning ring (902) along the operational axis (12) in the first direction (D1) and/or move with the rope tensioning ring in the second direction (D2).

The actuator system (904) may comprise a hydraulically operable cylinder (906) operable to move the rope tensioning ring (902) along the operational axis (12) in the first direction (D1) as fluid is pumped into and/or pressurised in the hydraulically operable cylinder (906) and move with the rope tensioning ring (902) in the second direction (D2) as fluid is removed from and/or reduced in pressure in the hydraulically operable cylinder (906).

The hydraulically operable cylinder (906) may comprise a pressure release valve (908), wherein the pressure release valve (908) is configured to open above a predetermined pressure (P1) of hydraulic pressure; and the pressure release valve (908) is configured to close below the predetermined pressure (P1) of hydraulic pressure.

The control bleed valve (908) may be configured to have a range of open and close values, such that the actuator system (904) is controllable to move the rope tensioning ring (902) to a range of positions along the operational axis (12).

The actuator system (904) may comprise at least two hydraulic cylinders (906) equally spaced apart around the rope tensioning ring (902). The housing assembly (600) may comprise walls (630, 632) which define an annular passage (634), the rope tensioning ring (902) being located in, and slideable along, the annular passage (634).

The rope tensioning ring (902) may comprise a fixing member (910) for each rope (1000) to lock the second end (1004) of the rope (1000) to the rope tensioning ring (902), and an aperture (650) is provided in one of the walls (630, 632) positioned to provide access to the fixing member (910), the fixing member (910) being operable release the second end (1004) of the rope (1000) from the rope tensioning ring (902).

The power tool (10) may further comprise a plurality of rods (640) held in a fixed relationship to one another by : a first mount (642) on the housing assembly (600) towards one end of the rods (640), and a second mount (644) on the housing assembly (600) spaced apart from the first mount (642) along the operational axis (12) towards an opposite end of the rods (640); and the body (700) defines tracks (710) which are engaged with the rods (640) to thereby constrain the motion of the body (700) along the operational axis (12).

The body (700) may be operable to translate from the impact position to the body retracted position along at least some of the rods (640) under the action of an actuator (800) and against the force developed by the elastic ropes (1000); and wherein the body (700) is biased to move along at least some of the rods (640) towards its impact position from its body retracted position by the elastic ropes (1000) whilst uncoupled from the actuator (800).

The body (700) may comprise a rope passage (720) which extends from a head end (730) of the body to a foot end (732) of the body (700), at least one of the ropes (1000) extending through the rope passage (720).

There may be provided a power tool (10) comprising: a tool carrier (100) for mounting an impact tool (102), the tool carrier (100) having a head end (110) and a foot end (112) at an opposite end of the tool carrier (100) to the head end (110); a body (700) constrained to move along the operational axis (12) from an impact position at which the body (700) is operable to transfer impact energy to the head end (110) of the tool carrier (100) to a body retracted position spaced apart from the impact position along the operational axis (12); and a monitoring system (1100) configured to determine the blow energy of the body (700), wherein the blow energy is the energy transferred from the body (700) to the head end (110) of the tool carrier (100).

The monitoring system (1100) may be configured to determine the blow energy as a function of the speed of the body (700) travelling from the body retracted position to the impact position.

The monitoring system (1100) may be configured to determine the speed of the body (700) as a function of: a. the distance between the body retracted position and the impact position; and b. the time taken to travel between the body retracted position and the impact position.

The monitoring system (1100) may comprise a first sensor unit (1110) configured to measure the speed and distance travelled by the body (700); wherein the monitoring system (1100) is in signal communication with the first sensor unit (1110) and configured to receive the body speed measurement and body distance measurement from the first sensor unit (1110).

The monitoring system (1100) may be configured to determine the blow energy as a function of the kinetic energy of the body (700) at the point of impact with the tool carrier (100), the kinetic energy of the body (700) at the point of impact with the tool carrier (100) being determined as a function of: the speed of the body (700) as it impacts with the head end (110) of the tool carrier (100); and the mass of the body (700).

The monitoring system (1100) may be configured to determine the speed and distance travelled by the tool carrier (100) in response to the impact energy delivered from the body (700).

The monitoring system (1100) may comprise a second sensor unit (1120) configured to measure the speed and distance travelled by the tool carrier (100) wherein the monitoring system (1100) is in signal communication with the second sensor unit (1120) and configured to receive the tool carrier speed measurement and tool carrier distance measurement from the second sensor unit (1120). The power tool (10) may comprise a storage medium (1200) for recording data received from the first sensor unit (1110), the second sensor unit (1120) and/or generated by the monitoring system.

The monitoring system (1100) may be operable to generate an alert and/or a signal when the blow energy is determined to be above and/or below a predetermined value.

The power tool (10) may further comprise a housing assembly (600) which defines a cavity (602) in which the body (700) and tool carrier (100) are located.

The power tool (10) may further comprise: a plurality of rods (640) held in a fixed relationship to one another by : a first mount (642) on the housing assembly (600) towards one end of the rods (640), and a second mount (644) on the housing assembly (600) spaced apart from the first mount (642) along the operational axis (12) towards an opposite end of the rods (640); the body (700) defines passages (710) in slideable engagement with at least some of the rods (640), the passages (710) being configured such that the body (700) may translate between the impact position and the body retracted position along at least said rods (640); wherein the monitoring system (1100) is configured such that when the speed of the body (700) is determined to be above and/or below a predetermined value the monitoring system (1100) generates an alert and/or a signal to indicate that the rods (640) and/or body (700) should be inspected.

The power tool (10) may further comprise: an array of elastic ropes (1000), a first end (1002) of each of the array of elastic ropes (1000) being coupled to the body (700), and a second end (1004) of each of the elastic ropes (1000) being coupled to the housing assembly (600) via an anchor system (900); the tension in each of the elastic ropes (1000) having a first value (T1) when the body is in the body retracted position and having a second value (T2) with the body (700) is in the impact position; wherein the monitoring system (1100) is configured such that when the speed of the body (700) is determined to be above and/or below a predetermined value the monitoring system (1100) generates an alert and/or a signal to indicate that the ropes (1000) should be inspected.

There may be provided a method of operation for a power tool (10), the power tool (10) having an operational axis (12) and comprising: a tool carrier (100) for mounting an impact tool (102), the tool carrier (100) having a head end (110) and a foot end (112) at an opposite end of the tool carrier (100) to the head end (110); a body (700) constrained to move along the operational axis (12) from an impact position at which the body (700) is operable to transfer impact energy to the head end (110) of the tool carrier (100) to a body retracted position spaced apart from the impact position along the operational axis (12); the method comprising monitoring the blow energy of the tool carrier (100), wherein the blow energy is the energy transferred from the body (700) to the head end (110) of the tool carrier (100).

The blow energy may be determined by the monitoring system as a function of the speed of the body (700) travelling from the body retracted position to the impact position.

The method of operation may further comprise the steps of: a. monitoring the speed of the body (700) and/or to the distance travelled by the body (700), and b. generating an alert and/or a signal if the speed and/or distance travelled by the body (700) is above and/or below a predetermined value.

The method of operation may further comprise the steps of: monitoring the speed of the tool carrier (100) and/or to the distance travelled by the tool carrier (100); and generating an alert and/or a signal if the speed and/or distance travelled by the tool carrier (100) is above and/or below a predetermined value.

The method of operation may further comprise the steps of: determining the deceleration of the tool carrier (100); generating an alert and/or a signal if the deceleration of the tool carrier (100) is above and/or below a predetermined value.

Hence there is provided a breaker power tool configured to absorb vibration induced by the impact force generating components of the power tool which reduces the amount of vibrational energy transmitted to a user or supporting equipment, as well as reducing operational noise. The breaker power tool of the present disclosure may also be operable to monitor, determine and indicate the blow energy to the tool being used (e.g. drill bit or the like) to break up the target which enables a user to determine if the power tool is delivering sufficient energy per blow to the tool, and thus indicate to the user whether the device is operating correctly and/or is delivering enough energy per blow of the tool to break the target. The breaker power tool of the present disclosure may also be operable to alter the energy per blow of the tool to the target, which enables the blow energy to be adjusted appropriate for the target and also allows for the blow energy to be restored to a desired level during maintenance of the breaker power tool (for example where blow energy has diminished over time due to wear on components of the breaker tool).

Brief Description of the Drawings

Examples of the present disclosure will now be described with reference to the accompanying drawings, in which:

Figure 1 shows a side view of a power tool according to the present disclosure;

Figure 2 shows a rear view of the power tool shown in figure 1 ;

Figure 3 shows a cross-sectional view of the device shown in figures 1 , 2, shown from the front, in a blank fire configuration;

Figure 4 shows a cross-sectional view of the device shown in figure 1 , 2, shown from front, in an impact position;

Figure 5 shows a cross-sectional view of the device shown in figures 1 , 2, shown from the side, in a pickup position;

Figure 6 shows a cross-sectional view of the device shown in figures 1 , 2, shown from the side, in a release/retracted position;

Figure 7 shows a cross-sectional view of the device shown in figures 1 , 2, shown from the front, in an extended position during a blank fire configuration;

Figure 8 shows a cross-sectional view of the device shown in figures 1 , 2, shown from the front, in a recoil position during a blank fire configuration;

Figure 9 shows some of the internal components of the power tool of the present disclosure (with the housing removed);

Figure 10 shows a first cross-sectional view of an energy transfer assembly of the power tool of the present disclosure;

Figure 11 shows a second cross-sectional view of the energy transfer assembly shown in figure 10;

Figure 12 shows an end on view of the energy transfer assembly shown in figures 10, 11 ;

Figure 13 shows a perspective view of a tool carrier of the energy transfer assembly; Figure 14 shows a perspective view of an engagement feature for engaging with the tool carrier;

Figures 15, 16 show different side views of the tool carrier shown in figure 13;

Figure 17 shows a top view of the engagement feature shown in figure 14;

Figure 18 shows a side view of the engagement feature shown in figure 17;

Figure 19 shows a part sectional view of the engagement feature shown in figure 18;

Figures 20, 21 show different sectional views of the energy transfer assembly;

Figure 22 shows internal components of the power tool of the present disclosure in an “impact” configuration;

Figure 23 shows internal components of the power tool of the present disclosure in a “rest” configuration;

Figures 24a-f show the operation of a “catch and release" interface of actuator and body according to the present disclosure;

Figures 25a-b show the operation the actuator and body according to the present disclosure in a “rest" or “blank fire” configuration;

Figure 26 is a sectional side view of the power tool indicating a region “E” showing a part of a tensioning system of the present disclosure;

Figure 27 shows a sectional view of region E indicated in figure 26 showing an actuator of the tensioning system;

Figure 28 shows a sectional view of region E indicated in figure 26 showing a rope tensioning ring of the tensioning system;

Figure 29 is a sectional view of the power tool indicating region “F” showing another part of the tensioning system;

Figure 30 shows an enlarged view of region “F” shown in figure 29;

Figure 31 shows sensor units according to the present disclosure;

Figure 32 shows a first sectional view of an alternative configuration of part of the power tool of the present disclosure; and

Figure 33 shows a second sectional view of the alternative configuration shown in figure 32.

Detailed Description

The present disclosure relates to a power tool 10, where the power tool is configured as a breaker device for delivering an impact force to a tool for cutting into, drilling or smashing a target, for example asphalt, concrete, rocks and the like. As will be described, the power tool 10 may be operated to apply a percussive force to a target object.

Although the figures of the present application show a jack hammer type tool, the power tool of the present disclosure may form part of any power tool where it is required to deliver a cyclic percussive force to a target object.

An external view of the power tool of the present disclosure is illustrated in figures 1 , 2, and sectional views are shown in figures 3 to 9.

The power tool 10 has an operational axis 12. As shown in figures 3 to 6, the power tool 10 comprises a tool carrier 100 for mounting an impact tool 102. The tool carrier 100 comprises a base member 104 aligned with the operational axis 12. The base member 104 may be centred on (i.e. concentric with) the operational axis 12.

The power tool 10 may further comprise a body 700 for impact with, and transmitting an impact force to, the tool carrier 100. As shown in figures 5, 6, 22, 23, 24a-f, 25a, b the body 700 may comprise a first flange 702 having a first engagement land 706 and a first engagement edge 704. The power tool 10 may further comprise an actuator 800 for moving the body 700 along the operational axis 12 from an impact position (as shown in figure 4) at which the body 700 is operable to transfer impact energy to the head end 110 of the tool carrier 100, to a body retracted (or “release”) position (shown in figure 6). Hence the position of the body 700 in the impact position (as shown in figure 4) is spaced apart from the position of body 700 in the body retracted (or “release”) position (shown in figure 6). Hence the body 700 is operable to move along the operational axis 12 in a first direction D1 from the retracted (or “release”) position (shown in figure 6) to the impact position (as shown in figure 4). Additionally the body 700 is operable to move along the operational axis 12 in a second direction D2 opposite to the first direction D1 from the impact position (as shown in figure 4) to the retracted (or “release”) position (shown in figure 6).

The power tool 10 may further comprise a housing assembly 600 comprising a plurality of housing modules including a first housing module 610 and a second housing module 620. The housing assembly 600 may include further housing modules in addition to the first housing module 610 and second module 620. Each of the modules of the housing assembly 600 comprise a wall which defines a cavity 602 in which the tool carrier 100 is located. The housing assembly 600 defines an opening 604 through which the tool member 100 extends such that the head end 110 of the tool carrier 100 is located inside the cavity 602 and the foot end 112 is located outside of the cavity 602.

The body 700 may be located in the first housing module 610 and the tool carrier 100 may be located within the first housing module 610, the second housing module 620 and extend outside of the housing assembly 600 through the opening 604.

The tool carrier 100 is operable to move along the operational axis 12 in the first direction D1 to an extended position (e.g. towards a target to be worked in, as shown in figure 7). The extended position (as shown in figure 7 and figure 23) is the furthest the tool carrier 100 can travel along the operational axis 12 in the first direction D1. When the tool carrier 100 (in addition any tool 102 attached thereto) is in contact with a target object (for example as shown in figure 22) then the tool carrier 100 is in a pick up position (as shown in figures 5, 8) or an impact position (as shown in figure 4). Both the pick up position and impact position are spaced apart from the extended position along the operational axis 12 in the second direction D2. Hence the tool carrier 100 must move from the pick up position and impact position along the operational axis 12 in the first direction D1 to arrive at the extended position. The tool carrier 100 will be in the extended position (as shown in figures 7, 23) when not in contact with a target object. That is, the tool carrier 100 will be in the extended position when the tool carrier 100 has been struck by the body 700 and the target object breaks, the tool carrier 100 (with tool 102) sinks into the target (for example if the target yield) or the tool carrier 100 is lifted away from the target so that the motion of the tool carrier is not fully halted by the target. This condition is referred to as a blank fire condition.

The tool carrier 100 is also operable to move along the operational axis 12 in the second direction D2 opposite to the first direction towards a tool carrier retracted position (as shown in figure 4 and figure 8).

Hence when the tool carrier 100 is in the tool carrier retracted position (as shown in figure 4 and figure 8), it is in the correct position to be struck by the body 700 at the impact position. The base member 104 has a head end 110 for receiving the impact energy from the second direction D2 (i.e. in the first direction D1) along the operational axis 12. The base member 104 also has a foot end 112 at an opposite end of the tool carrier 100 to the head end 110, the foot end 112 being provided with a tool mount 114 configured to hold a tool 102. The tool mount 114 is configured to transmit the impact energy to a tool fitted to the tool mount.

As shown in figures 3 to 8, the power tool 10 further comprises a first damper 200 provided to decelerate the tool carrier 100 in the first direction D1 along the operational axis 12 to bring it to a stop in the tool carrier extended position (as shown in figure 3). Hence the first damper 200 is configured to decelerate the tool carrier 100 when moving in the first direction D1 to thereby bring it to a halt at the tool carrier extended position, and absorb kinetic energy of the tool carrier 100. Hence the first damper 200 is positioned and operable to absorb kinetic energy from the tool carrier 100 when the power tool 10 is in a blank fire condition.

The power tool 10 further comprises a second damper 300 provided to decelerate the tool carrier 100 in the second direction D2 along the operational axis 12 to bring it to a stop at the tool carrier retracted position. Hence the second damper 300 is configured to decelerate the tool carrier 100 when moving in the second direction D2 and to bring the tool carrier 100 to a halt and absorb kinetic energy of the tool carrier 100. Hence the second damper 300 is positioned and operable to absorb kinetic energy when the power tool 10 is in a blank fire condition. That is to say, the tool carrier 100 may engage with the second damper 300 during a blank fire condition as the tool carrier 100 may rebound from the first damper 100 (i.e. after striking the first damper 200 moving in the first direction D1) to move along the operational axis 12 in the second direction D2.

As shown in figures 3 to 6, the power tool 10 may further comprise a support plate 400 provided with an aperture 402 through which the tool carrier 100 extends. The support plate 400 may also be configured as a coupling member, for example providing a link between two housing modules of the power tool 10. For example, the support plate 400 may be configured as a coupling member to couple the first housing module 610 and second housing module 620, for example providing a link between two sections/modules of housing of the power tool 10. The support plate (or coupling member) 400 may be formed integrally with one of the housings/casings of the power tool 10. For example, the support plate 400 may be cast as part of the first casing module 610 or the second casing module 620. Alternatively the support plate 400 may form part of an assembly which defines the first casing module 610 or the second casing module 620.

Hence the first housing module 610 may be coupled to the support plate 400, and hence the first housing module 610 may be coupled to the second housing module 620 by virtue of being coupled to the support plate 400.

The tool carrier 100 may comprise a first damper retaining feature 210 provided between the head end 110 of the tool carrier 100 and the support plate 400. The first damper 200 is provided between the first damper retaining feature 210 and the support plate 400.

The tool carrier 100 may further comprise a second damper retaining feature 310 provided between the foot end 112 of the tool carrier 100 and the support plate 400. The second damper 300 is provided between the second damper retaining feature 310 and the support plate 400.

Figures 32, 33 show an alternative example of a part of the power tool of the present disclosure. Figure 33 shows a different section to that of figure 32. That is to say, figures 32, 33 relate to the same example, the view in figure 33 being rotated about the operational axis relative to that shown in figure 32, and thereby illustrating a different combination of features.

In the examples shown in figures 32, 33, the tool carrier 100 further comprises a second damper retaining feature 310 provided between the foot end 112 and the support plate 400. In this example the second damper 300 is provided between the second damper retaining feature 310 and a support land 660. The support land 660 extends from the housing assembly 600. The support land 660 is spaced apart from the support plate 400 along the operational axis 12. The support plate 400 and the support land 660 may each form a different part of the housing assembly 600.

The second damper retaining feature 310 is spaced apart from the support plate 400 along the operational axis 12. The first damper retaining feature 210 may further comprise a first damper support land 212 which is coupled to, and extends radially from, the tool carrier 100 to prevent the first damper 200 from moving past the first damper support land 212 in the second direction D2. The second damper retaining feature 310 may comprise a second damper support land 312 which is coupled to, and extends radially from, the tool carrier 100 to prevent the second damper 300 from moving past the second damper support land 312 in the first direction D1.

The first damper 200 and second damper 300 are provided on opposite sides of the coupling member (support plate) 400, and are each operable to absorb impact energy (i.e. the kinetic energy of the tool carrier 100) if the tool carrier 100 moves beyond certain point along the operational axis 12. Thus the action of the tool carrier 100 moving in the first direction D1 will cause the support land 212 (first damper retaining feature 210), coupled to the tool carrier 100, to press against the first damper 200, hence pressing the first damper 200 against the support plate 400. The action of the tool carrier 100 moving in the second direction D2 will cause the second damper retaining feature 310 to press against the second damper 300, hence pressing the second damper 300 against the support plate 400.

Hence the configuration in Figure 7 shows an extended position of the tool carrier which is the result of a blank fire (i.e. the position the tool carrier may reach after being struck when not in contact with a target object (e.g. as shown in figure 23) and also shows the first damper 200 compressed as a result of slowing the tool carrier 100 in the first direction D1.

Figure 8 shows recoil position of the tool carrier 100 (i.e. the position it takes up after rebounding from the position shown in Figure 7 and also shows the second damper 200 compressed as a result of slowing the tool carrier 100 in the second direction D2. Figure 8 also shows the tool carrier 100 in a position where the tool is being pressed against the ground, perhaps causing additional compression of the second damper 200.

The first damper 200 may comprise a first damping member 214 which extends around the tool carrier 100. The second damper 300 may comprise a second damping member 314 which extends around the tool carrier 100. The first damping member 214 and/or second damping member 314 may each be formed as rings. The damper rings may extend around the tool carrier 100.

Alternatively the first damper 200 and or second damper 300 may each be formed as a single (i.e. integrally formed) unit.

The first damper 200 may comprise at least two first damping members 214 in series along the operational axis 12, wherein the at least two first damping members 214 have a different stiffness and/or shore hardness to one another, or the same stiffness and/or shore hardness as one another. The second damper 300 may comprise at least two second damping members 314 in series along the operational axis 12. The at least two second damping members 314 may have a different stiffness and/or shore hardness to one another, or the same stiffness and/or shore hardness as one another.

The dampers may be approximately 70-shore hardness.

In one example, the first damper 200 and/or second damper 300 may include protective plates (for example, made of metal) at least one end. For example a protective plate may be provided on the end of the first damper 200 which faces the first damper retaining feature 210 and/or a protected plate may be provided on the end of the first damper 200 which faces the support plate 400. Additionally or alternatively a protective plate may be provided on the end of the second damper 300 which faces the second damper support land 312 and/or a protective plate may be provided on the end of the second damper 300 which faces the support plate 400.

The first damper 200 and/or second damper 300 may travel with the tool carrier 100 along the operational axis 12.

There may be a clearance fit, or sliding fit, between the first damper 200 and the tool carrier 100, and/or there may be a clearance fit, or sliding fit, between second damper 300 and the tool carrier 100.

The first damper 200 and/or second damper 300 may be fixed relative to the support plate 400 such that the tool carrier 100 is moveable relative to the first damper 200 and/or second damper 300 along the operational axis 12. The first damper 200 and/or the second damper 300 may be fixed relative to the housing assembly 600 such that the tool carrier 100 is moveable relative to the first damper 200 and/or the second damper 300 along the operational axis 12.

In the example of figure 32, the first damper 200 may be fixed relative to the support plate 400 and the second damper may be fixed relative to the support land 660 such that the tool carrier 100 is moveable relative to the first damper 200 and/or second damper 300 along the operational axis 12.

The base member 104 of the tool carrier 100 is illustrated in figures 3 to 8, 10, 11 , 13, 15, 16. As illustrated in figures 15, 16, the base member 104 may comprise a first section 130 which extends from the head end 110 towards the foot end 112 with a constant diameter (e.g. cylindrical) along its length to a second section 132. The second section 132 may extend from the first section 130 towards the foot end 112 with an increasing diameter (e.g. frustoconical) to a third section 134. The third section 134 may extend, with a constant diameter (e.g. cylindrical), from the second section 132 towards a fourth section 136 at the foot end 112. The fourth section 136 may define the foot end 112 and tool mount 114.

Each section of the base member 104 of the tool carrier 100 may comprise a circular cross-section, as least along some of its length.

The tool mount 114 (at the foot end 112 of the tool carrier 100) may comprise a tool coupling land 150 which extends a right angles to the operational axis 12. The tool 102 may comprise a tool carrier coupling land 156 complementary in shape with, and configured to engage with, the tool coupling land 150. The engagement land 150 may comprise a first location feature 152 (for example a passage) configured to couple with a second location feature 154 (for example a spigot or bolt) on the tool 102.

The tool 102 may be provided as a wear plate 160 which is configured to cover the foot end 112 of the tool carrier 100.

The wear plate 160 may define a free surface 162 for striking a target object. In the example shown in the figures, the free surface 162 may in part be convex and in part flat. In other examples the free surface 162 may be convex or flat. In further examples the free surface may be provided as a chisel or blade. The third section 134 of the tool carrier 100 may define engagement lands 140 provided as flat regions. The engagement lands 140 may extend from the third section 134 to the first section 132. The power tool 10 may further comprise a tool carrier engagement feature 500 complementary in shape to, and for engagement with, the tool carrier engagement lands 140 to thereby prevent rotation of the tool carrier 100 around the operational axis 12, and permit movement of the tool carrier 100 along the operational axis 12. Hence the tool carrier engagement feature 500 is configured to engage with the engagement lands 140 on the third section 134 of the tool carrier 100, with a clearance fit and/or sliding fit therebetween so that the tool carrier 100 is operable to move along the operational axis 12 relative to the tool carrier engagement feature 500. The tool carrier engagement feature 500 may be provided as a spigot fit square drive as illustrated in Figures 14, 17, 18, 19. Hence the tool carried engagement feature 500 may be provided as a ring which defines an aperture 502 with flats 540 for cooperative engagement with the engagement lands 140 of the tool carrier 100. In the example shown two engagement lands 140 are provided on the tool carrier 100, diametrically opposite one another, and two flats 540 form part of the aperture 502 of the tool carrier engagement feature 500 ring.

As best shown in figures 3 to 8, the tool carrier engagement feature 500 is coupled to the housing assembly 600 in the region in which the third section 134 of the tool carrier 100 is located. In the present example this is coupled to the second housing module 620.

Hence the tool carrier engagement feature 500 is configured, and mounted to the housing assembly 600 to thereby prevent rotation of the tool carrier 100 relative to the housing assembly 600, to prevent rotation of the tool carrier 100 around the operational axis 12, and permit relative movement between the tool carrier 100 and the housing assembly 600 along the operational axis 12.

In the examples of figures 32, 33, the wall 632 defines a chamber 636 through which the base member 104 of the tool carrier 100 extends. That is to say, the wall 632 bounds the base member 104, and a clearance is maintained between the inner surface of the wall 632 and the tool carrier 100. As shown in figure 33, the wall 632 defines a first groove 638 and the base member 104 defines a second groove 106. A key member 108 is located in, and extends between, the first groove 636 and the second groove 106 to thereby prevent rotation of the tool carrier 100 relative to the wall 632, and hence prevent rotation of the tool carrier 100 around the operational axis 12. The first groove 638 and second groove 106 may extend in a direction parallel to the operational axis 12 (e.g. longitudinally). One or more pairs of first groove 638 and second groove 106 may be provided around the circumference of the base member 104 and tool carrier 100.

The second damper support land 312 may be fitted to the second section 132 of the tool carrier 100 (see figures 3 to 6). Hence the second damper support land 312 may be provided as ring which extends around the second section 132. Since the second section is frustoconical, the second damper support land 312 may be held in place by an interference fit with the second section 132.

As illustrated in figures 5, 6 and figures 22, 23 the actuator 800 may comprise a first actuator rotational axis 802, and a first engagement member 804 offset from, and rotatable around, the first actuator rotational axis 802. The actuator 800 may be operable to be hydraulically actuated.

The first actuator rotational axis 802 may be perpendicular to the operational axis 12. The first flange engagement edge 704 may be aligned (e.g. parallel) with the first actuator rotational axis 802. The first flange 702 may extend away from the first flange engagement edge 704 in a direction away from the first actuator rotational axis 802 and perpendicular to the operational axis 12.

As shown in figures 24a to 24f the first engagement member 804 and first flange 702 may be arranged relative to each such that at the impact position (or pick up position) (as shown in figures 24a, 24b, and figures 4, 5, 22) the first engagement member 804 is operable to engage with the first flange engagement edge 704. As the first engagement member 804 rotates around the first actuator rotational axis 802 (as shown in figures 24b, 24c), the first engagement member 804 travels along the first flange 702 engagement land 706 and simultaneously urges the body 700 in a direction away from the body 700 impact position towards the body retracted position (as shown in figure 22d and figure 6). At the body retracted position (as shown in figure 24d and figure 6) the first engagement member 804 is operable to move past the first flange engagement edge 704 to thereby disengage the body 700 from the first engagement member 804 (as shown in figure 24e), thereby permitting the body 700 to move on an impact stroke to the impact position (as shown in figure 24f).

The body 700 is operable to travel along the operational axis 12 between the impact position and a rest position (i.e. blank fire position as shown in figures 3, 7, 25a, 25b) spaced apart from the impact position along the operational axis in a direction away from the actuator 800.

As illustrated in figures 23, 25a, 25b, when the power tool is in a blank fire condition (i.e. at the rest position as shown in figures 3, 7) the first engagement member 804 is engaged with the edge 704 of the first flange 702 and held in position until first flange 702 moves up, for example in response to the body 700 (to which the flange 702 is connected) by the tool carrier 100 when the tool 102 is placed in contact with a target and weight is placed on the target by the power tool.

Put another way, when the body 700 is moved beyond the impact position in a direction away from the actuator 800 (i.e. towards or at the rest position as shown in figure 3, 7, 23) the relative position of the first engagement member 804 and edge 704 of the first flange 702 is such that the engagement member 804 cannot extend under the flange 702 to pick up the body 700, and hence the engagement member 804 sits against the first flange 702 until the body 700 is moved towards the actuator rotational axis 802 when the tool 102 is placed in contact with a target and weight is placed on the target by the power tool.

Hence as shown in figure 25a, the first engagement member 804 approaches the first flange 702 and then abuts the first flange (as shown in figure 25b) such that the flange 702 prevents the first engagement member 804 from rotating further around the actuator rotational axis 802.

Hence when the tool carrier 100 (and hence body 700) are “at rest” (for example as shown in Figure 7) the actuator 800 is not able to lift the body 700 until the tool is pressed against the ground again. Hence in the arrangement of the present disclosure, only one blank fire per blank fire event is possible, which reduces the opportunity for damage occurring due to blank fire.

Hence the power tool of the present disclosure includes an advantageous damping system including the first damper 200 and second damper 300 which are configured and operable to absorb shock loads imparted to the tool carrier 100 during a misfire. This is extremely important as it prevents vibration and loads being transmitted to the housing assembly 600 of the power tool 10 and hence to the vehicle carrying the power tool 10. Since the carrier vehicle is exposed to less vibration and shock loads, the life of its components are increased. Additionally, the operator of the carrier vehicle is more comfortable, and hence can operate the device for longer and more effectively.

The tool carrier 100 also allows for easy replacement of tools, for example to achieve a different cutting operation, or to replace a damaged tool.

Additionally, the shape of the tool carrier 100, increasing in diameter along its length, provides the benefit of a tool carrier shape which is resistant to high forces, increasing the life of the tool carrier.

The flats 140 on the tool carrier 100 in combination with the tool carrier engagement feature 500, where the flats are provided on a region of increased diameter of the tool carrier, results in an arrangement in which is capable to resist large torque forces around the operational axis 12. This is important as a tool 102 to be fitted may have a cutting form which is directional (for example a wide chisel) which means that not only will its integration with a target result in large rotational forces around the operational axis, but that is it imperative that the tool carrier is not able to rotate about the operational axis as the tool 102 would not be possible to locate on the target.

The tool mounting arrangement, e.g. bolts, spigots on a flat end, mean that a tool 102 can be fitted without compromising the tool carrier (for example by needed a cavity to receive the tool) and that the tool 102 may be more easily removed (e.g. because there is no cavity for it to get stuck into).

As described below, the body 700 may be constrained to move along the operational axis 12 from the impact position at which the body 700 is operable to transfer impact energy to the head end 110 of the tool carrier 100 to the body retracted position spaced apart from the impact position along the operational axis 12.

As shown in figures 5, 6, there may also be provided an elastic rope 1000, a first end 1002 of the elastic rope 1000 being coupled to the body 700, and a second end 1004 of each of the elastic rope 1000 being coupled to the housing assembly 600 via an anchor system 900. The rope 1000 is tensioned by the action of the body 700 being moved from the impact position to the retracted position by the actuator 800. The tension in the elastic rope 1000 has a first value T1 when the body is in the body retracted position and having a second value T2 with the body 700 is in the impact position.

The elastic rope 1000 may be one of an array of elastic ropes 1000, the first end 1002 of each of the ropes of the array of elastic ropes 1000 being coupled to the body 700, and the second end 1004 of each of the elastic ropes 1000 being coupled to the housing assembly 600 via an anchor system 900. The tension in each of the elastic ropes 1000 may have a first value T 1 when the body is in the body retracted position and having a second value T2 with the body 700 is in the impact position. The anchor system 900 may be operable to alter the position of the second end 1004 of each of the ropes 1000 relative to the first end 1002 in a direction along the operational axis 12 to thereby adjust the first tension value T1 at the body retracted position and thereby adjust the second tension value T2 at the impact position.

The energy stored in the rope(s) at the retracted position drives the body 700 towards the head end 110 of the tool carrier to deliver an impact force (i.e. blow energy) to the tool carrier 700, which is transmitted to the tool 102 and then the target object.

The anchor system 900 may be operable to alter the position of the second end 1004 of the rope 1000 relative to the first end 1002 of the rope 1000 in a direction along the operational axis 12 to thereby adjust the first tension value T1 at the body retracted position and thereby adjust the second tension value T2 at the impact position.

In one example, for each rope 1000, when in situ in the power tool 10, the distance between the first end 1002 and the second end 1004 at the impact position may be greater than the un-extended length of each rope 1000, such that at the impact position each rope is held in tension. Additionally, or alternatively, the ropes may be structured such that at the impact position, i.e. when they are at their shortest, a resilient part of the rope is held in tension.

For example, each rope may comprise a natural rubber core within a sheath (for example a braided sheath) where the sheath fixes the ends of the rubber core to hold the rubber core in tension even when no external load is applied to the rope. This is advantageous as with a natural rubber core the constant tension in the rubber core promotes strain crystallisation which increases the loading capacity of the rope (i.e. how much tension can be induced before failure) and the cycling life of the rope (i.e. how many times it can be stretched and then released). This is because strain crystallisation promotes the growth of crystals in any crack formed within the natural rubber, and hence stops the crack developing.

As shown in figure 3 to 6, the anchor system 900 may comprise a rope tensioning ring 902 which is centred on, and extends around, the operational axis 12. In the example shown in the figures, the second end 1004 of the ropes 1000 are coupled to the rope tensioning ring 902.

The housing assembly 600 may comprise walls 630, 632 which define an annular passage 634, the rope tensioning ring 902 being located in, and slideable along, the annular passage 634. In the example of figures 32, 33 the walls 630, 632 extend from the support plate 400 to the region of the housing assembly 600 which defines the support land 660.

Hence the tensioning ring 902 is located in the annular passage 634 and may travel along the annular passage 634 in the first direction D1 and in the second direction D2. Hence the rope tensioning ring 902 may be moveable along the operational axis 12 in the first direction D1 and second direction D2 along the operational axis 12 to thereby alter the position of the second end 1004 of each of the ropes 1000 relative to the first end 1002 of the ropes 1000 in a direction along the operational axis 12.

In the example of figure 32, the power tool 10 comprises a tensioning member 410 mounted to the housing assembly 600 and coupled to the rope tensioning ring 902. The tensioning member 410 is operable to move the rope tensioning ring 902 along the operational axis 12 in the first direction (D1) and/or move the rope tensioning ring along the operational axis 12 in the second direction (D2). In the example of figure 32, the tensioning member 410 is fixed to, and rotatably mounted to, the housing assembly 600. In this example the tensioning member 410 is also rotatably coupled to the rope tensioning ring 902. In the example of figure 32 the tensioning member 410 extends from the support plate 400, through the annular passage 634 to the region of the housing assembly 600 which defines the support land 660.

In the example of figure 32 the rope tensioning ring 902 defines a threaded aperture 920 through which the tensioning member 410 extends. The tensioning member 410 is provided with a thread 414 compatible with the thread 922 of the aperture 920 to thereby couple the tensioning member 410 and rope tensioning ring 902 together. For example, the tensioning member 410 may be provided as a threaded bolt. When coupled (i.e. when the tensioning member 410 is entered into the threaded aperture 920) the tensioning member 410 is rotatable relative to the rope tensioning ring 902. Rotation of the tensioning member 410 causes the rope tensioning ring 902 to move along the tensioning member 410. Hence if the tensioning member 410 is rotated in a first rotational direction, the rope tensioning ring 902 is moved along the operational axis 12 in the first direction (D1). If the tensioning member 410 is rotated in a second rotational direction (opposite to the first rotational direction) the rope tensioning ring is moved along the operational axis 12 in the second direction (D2).

The tensioning member 410 may extend to a free end 924. The free end 924 may be provided with an engagement feature 926 for engagement with a tool for rotating the tensioning member 410.

As shown in figures 3, 4 (which is a different sectional view to that of figures 5, 6 - that is to say a different sectional view of the same power tool example) the power tool 10 may further comprise an actuator system 904 mounted to the housing assembly 600 and which extends to (e.g. is coupled to) the rope tensioning ring 902. The actuator system 904 may be operable to move the rope tensioning ring 902 along the operational axis 12 in the first direction D1 and/or move with the rope tensioning ring in the second direction D2

As shown in figure 27, in a region of the power tool indicated by region E in figure 26, the actuator system 904 may comprise a hydraulically operable cylinder 906 operable to move the rope tensioning ring 902 along the operational axis 12 in the first direction D1 as fluid is pumped into and/or pressurised in the hydraulically operable cylinder 906 and move with the rope tensioning ring in the second direction D2 as fluid is removed from and/or reduced in pressure in the hydraulically operable cylinder 906. Hence, as shown in figure 27, one end of the cylinder 906 may be coupled to the rope tensioning ring 902. The other end of the cylinder 906, as shown in figure 30 in a region F of the power tool indicated in figure 29, may be anchored to the housing assembly 600. Hence the (or each) cylinder 906 may extend from where it is anchored on the housing assembly 600 In the first direction D1 towards the rope tensioning ring 902.

The cylinder 906 comprises an intake for hydraulic fluid from a source of hydraulic fluid, for example a pump associated with power tool, or a pressurised source on a vehicle (for example a backhoe loader) which carries the power tool 10. The cylinder may be a single acting cylinder, in that once a fluid pressure has been set the length of the cylinder is fixed until fluid is released from the cylinder, for example from a release valve 908 in fluid communication with the cylinder.

The actuator system 904 may comprise a hydraulically operable cylinder 906 with a pressure release valve 908. The pressure release valve 908 may be configured to open above a predetermined pressure P1 of hydraulic pressure, for example to prevent the ropes 1000 from being extended to more than the first tension value T1. The pressure release valve 908 may be external to the housing assembly 600, for example fitted to an external surface of the housing as shown in figure 2.

The pressure release valve 908 may be configured to close below the predetermined pressure P1 of hydraulic pressure, for example to prevent the ropes 1000 from being extended to less than the first tension value T1 .

The control bleed valve 908 may be configured to have a range of open and close values, such that the actuator system 904 is controllable to move the rope tensioning ring 902 to a range of positions along the operational axis 12.

The actuator system 904 may comprise at least two hydraulic cylinders 906 equally spaced apart around the rope tensioning ring 902 and the operational axis 12. As best shown in figure 28, the rope tensioning ring 902 may comprise a fixing member 910 for each rope 1000 to lock the second end 1004 of the rope 1000 to the rope tensioning ring 902, and an aperture 650 provided in one of the walls 630, 632 positioned to provide access to the fixing member 910. The fixing member 910 may be operable to release the second end 1004 of the rope 1000 from the rope tensioning ring 902.

As shown in figures 5, 6, the power tool 10 may further comprise a plurality of rods 640 held in a fixed relationship to one another by a first mount 642 on the housing assembly 600 towards one end of the rods 640, and a second mount 644 on the housing assembly 600 spaced apart from the first mount 642 along the operational axis 12 towards an opposite end of the rods 640. The body 700 may define tracks (e.g. passages) 710 which are engaged with the rods 640 to thereby constrain the motion of the body 700 along the operational axis 12.

The body 700 may be operable to translate from the impact position to the body retracted position along at least some of the rods 640 under the action of the actuator 800 and against the force developed by the elastic ropes 1000. The body 700 may be biased to move along at least some of the rods 640 towards its impact position from its body retracted position by the elastic ropes 1000 whilst uncoupled from the actuator 800.

The body 700 may comprise a rope passage 720 which extends from a head end 730 of the body to a foot end 732 of the body 700, at least one of the ropes 1000 extending through the rope passage 720.

The ability to vary the rope tension results in a system in which the kinetic energy of the body 700 may be varied - for example to tune the blow energy to a value required for a particular target material and/or to restore any loss in performance easily.

The power tool 10 may further comprise a monitoring system 1100 configured to determine the blow energy of the body 700, wherein the blow energy is the energy transferred from the body 700 to the head end 110 of the tool carrier 100.

The monitoring system 1100 may be configured to determine the blow energy as a function of the speed of the body 700 travelling from the body retracted position to the impact position . That is to say the monitoring system 1100 may be configured to determine the blow energy as a function of the average speed of the body 700 travelling from the body retracted position to the impact position.

The monitoring system 1100 may be configured to determine the speed of the body 700 as a function of (a) the distance between the body retracted position and the impact position; and (b) the time taken to travel between the body retracted position and the impact position.

The monitoring system 1100 may comprise a first sensor unit 1110 configured to measure the speed and distance of the body 700. The monitoring system 1100 may be in signal (e.g. data) communication with the first sensor unit 1110 and configured to receive the body speed measurement and body distance measurement from the first sensor unit 1110. The first sensor unit 1110 may be located in the body 700.

The monitoring system 1100 may be configured to determine the blow energy as a function of the kinetic energy of the body 700 at the point of impact with the tool carrier 100, the kinetic energy of the body 700 at the point of impact with the tool carrier 100 being determined as a function of (a) the speed of the body 700 as it impacts with the head end 110 of the tool carrier 100; and (b) the mass of the body 700.

Blow energy may be calculated by :

(0.5 mass x velocity ^A 2) + potential energy (mass x distance x gravity).

Additionally or alternatively, the monitoring system 1100 may be configured to determine the speed and distance travelled by the tool carrier 100. Hence the monitoring system 1100 may be configured to determine the speed and distance travelled by the tool carrier 100 in response to the impact energy delivered from the body 700.

The monitoring system 1100 may comprise a second sensor unit 1120 configured to measure the speed and distance travelled by the tool carrier 100. The monitoring system 1100 may be in signal (e.g. data) communication with the second sensor unit 1120 and configured to receive the tool carrier speed measurement and tool carrier distance measurement from the second sensor unit 1120. The second sensor unit 1120 may be located in the tool carrier 100.

As shown in figure 31 , the monitoring system 1100 may comprise a central core member 1130 which extends from a signal hub 1132, the hub 1132 mounted to the housing assembly and the core member 1130 extending along the operational axis 12 through passages provided in the body 700 and tool carrier 100. The first sensor unit 1110 may be configured to slide along the core member 1130 with the body 700 and the second sensor unit 1120 may be configured to slide along the core member 1130 with the tool carrier 100, each of the sensor units 1110, 1120 configured to co-operate with the core member 1130 to generate a signal (for example a signal representing speed and/or distance travelled by the respective sensor units 1110, 1120).

The sensor units 1110, 1120 are operable to generate a signal when moving in the first direction D1 and second direction D2. The monitoring system is operable to measure, determine and record the dynamics of the tool carrier 100 and body 700 in breaking mode (ie when on contact with a target which is to be broken) and during a misfire, when the tool carrier 100 may rebound along the operational axis 12.

The power tool 10 may comprise a storage medium 1200 for recording data received from the first sensor unit 1110, second sensor unit 1120 and/or generated by the monitoring system.

The monitoring system 1100 may be operable to generate an alert and/or a signal when the blow energy is determined to be above and/or below a predetermined value. The alert and/or signal may be stored in a log and/or database for review by a user during and/or after the operation of the power tool 10.

The monitoring system 1100 may be configured such that when the speed of the body 700 and/or distance travelled by the body 700 is determined to be above and/or below a predetermined value the monitoring system 1100 generates an alert and/or a signal to indicate that component of the power tool 100 (for example the rods 640 and/or body 700, any bearings or low friction coatings on the rods, the ropes 1000) etc should be inspected. The monitoring system 1100 may be configured such that when the speed of the tool carrier 100 and/or distance travelled by the tool carrier 100 is determined to be above and/or below a predetermined value the monitoring system 1100 generates an alert and/or a signal to indicate that component of the power tool 100 (for example the dampers 200, 300) should be inspected.

Hence there may be provided a method of operation of the power tool 10 comprising the step of monitoring the blow energy of the tool carrier 100. The method of operation may further comprise the steps of (a) monitoring the speed of the body 700 and/or to the distance travelled by the body 700, and (b) generating an alert and/or a signal if the speed and/or distance travelled by the body 700 is above and/or below a predetermined value.

The method of operation may further comprise the steps of (a) monitoring the speed of the tool carrier 100 and/or to the distance travelled by the tool carrier 100; and (b) generating an alert and/or a signal if the speed and/or distance travelled by the tool carrier 100 is above and/or below a predetermined value.

The method of operation may further comprise the steps of (a) determining the deceleration of the tool carrier 100 (for example as a function of the speed and/or distance values); and (b) generating an alert and/or a signal if the deceleration of the tool carrier 100 is above and/or below a predetermined value.

Hence the method of operation may comprise the step of monitoring and generating an output which indicated the behaviour (i.e. performance) of the body 700 instantaneously and over time. Thus a user can determine what the blow energy is, and also determine if the blow energy delivered has changed, which indicated some maintenance may be required.

Hence the method of operation may comprise the step of monitoring and generating an output which indicates the behaviour (i.e. performance) of the tool carrier 100 instantaneously and over time. Thus a user can determine whether blank fire energy is being dissipated quickly enough, and how the dissipation characteristic has changed, which indicates some maintenance may be required. For example, with such information, one could infer compression (reduction in size) and rate of compression of dampers 200, 300, and thus can work out how much energy transferred from the body of tool. Hence if distance travelled by the tool carrier 100 (i.e. compression) is small, then there is a bigger shock force, and hence informs a user that the dampers may need to be swapped for others with a different damping property. That is to say, during a blank fire, the tool carrier 100 travels a measured distance along the operational axis. If the measured distance is less than a known preferred distance, then deceleration is less that desired, and may indicate that dampers are not damping adequately. Conversely, if the distance travelled and deceleration are greater than required, then dampers are performing better than required, and a life of the dampers may be determined.

The monitoring system may also be able to determine if a blank fire has occurred, for example because the toll carrier is travelling back and forth along the operational axis 12 by a greater distance and/or at greater speed than when the tool 102 is in contact with a target. Hence the monitoring system may generate an alert for the user and/or stop the actuator 800.

Thus a power tool 10 comprising a monitoring system as herein described enables a user to monitor the energy output of the body 700 and tool carrier 100, as well as monitoring the physical behaviours of the body 700 and tool carrier 100 to thus determine if the device is operating as required or whether adjustment/maintenance is required.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.