Patent Description:
Some professional demolition and construction tools are required to perform heavy duty tasks such as breaking concrete etc. One such tool is a demolition hammer power tool which comprises a reciprocating hammer operatively coupled to a motor. During operation, the motor may experience high load conditions and this may mean that the motor will get hot during operation. In order to ensure the motor performs under optimal conditions during operation the motor is cooled.

It is known to cool the motor with a fan which draws a cooling airflow over the motor during operation. For example, <CIT> discloses an electric hand tool with air intake openings for a fan. The electric hand tool comprises a cool air pipe having an elastic section which connects the air intake openings from an outer housing to the motor.

A problem with this arrangement is that the movement of the hammer causes the elastic section to stretch and compress during each reciprocating movement of the hammer. The elastic section must be durable but the reciprocating movement may still cause excessive wear on the elastic section which can require maintenance or even break. A user of the hammer power tool may not know that the elastic section has failed and subsequent use of hammer power tool can overheat the motor during operation. This can lead to catastrophic failure of the demolition power tool.

<CIT> discloses a power tool having the features of in the pre-characterising portion of claim <NUM>.

<CIT> discloses a power toll with an ir path which forms part of the cooling system. <CIT> discloses a chain saw having an internal combustion engine with a fan, the air flow of which passes through a set of bellows.

Examples of the present disclosure aim to address the aforementioned problems.

According to an aspect of the present disclosure there is provided a power tool according to claim <NUM>.

According to claim <NUM>, the first end of the at least one air conduit is fixed with respect to the motor fan assembly.

According also to claim <NUM>, the second end of the at least one air conduit is moveable with respect to the housing.

Further according to claim <NUM>, the second end of the at least one air conduit is slidably engageable with an inner surface of the housing.

Optionally, the second end of the at least one air conduit is configured to form a seal against the inner surface of the housing.

Optionally, the second end of the at least one air conduit comprises a lip configured to wipe the inner surface of the housing.

Optionally, the inner surface comprises an air hole.

Optionally, the second end of the at least one air conduit is configured to move from a first position to a second position and the second end and the second end covers the air hole.

Optionally, the at least one air conduit is flexible.

Optionally, the at least one air conduit comprises bellows.

Optionally, the at least one air conduit is a rubber, rubber-like materials, thermoplastic elastomers (TPE), or silicone material.

Optionally, the at least one air conduit comprises a pressure differential with respect to atmospheric pressure when the motor fan assembly is actuated.

Optionally, the inner mechanism is configured to reciprocally move in a direction parallel with a longitudinal axis of the power tool.

Optionally, the at least one air conduit is configured to slidably engage with an inner surface of the housing in a direction parallel with the longitudinal axis.

Optionally, the air inlet is mounted on a side of the housing.

Optionally, the inner mechanism comprises at least one dampener configured to engage the housing when the inner mechanism moves with respect to the housing.

Optionally, the first end of the air conduit comprises a groove configured to mount on a reciprocal projecting rib on a motor housing of the motor fan assembly.

Optionally, the power tool is a demolition hammer, plunge saw, a reciprocating saw, a circular saw, an impact driver, a drill, a hammer drill, a multitool, an oscillating tool, a rotary hammer, a chipping hammer, a plate compactor, a rammer, a tamper, a soil compactor, a pavement breaker or any other power tool.

Accordingly, there is provided a power tool in accordance with claim <NUM>.

Various other aspects and further examples are also described in the following detailed description and in the attached claims with reference to the accompanying drawings, in which:.

<FIG> shows a side view of a power tool <NUM>. The power tool <NUM> as shown in <FIG> is a demolition hammer. Whilst <FIG> shows a demolition hammer, in other examples any other type of power tool <NUM> can be used. For example, the power tool <NUM> can be a plunge saw, a reciprocating saw, a circular saw, an impact driver, a drill, a hammer drill, a multitool, an oscillating tool, a rotary hammer, a chipping hammer, a plate compactor, a rammer, a tamper, a soil compactor, a pavement breaker or any other power tool.

The power tool <NUM> comprises a housing <NUM>. The housing <NUM> comprises a clam shell type construction having two halves which are fastened together. The halves of the housing <NUM> are fastened together with screws but in alternative examples any suitable means for fastening the housing <NUM> together may be used such as glue, clips, bolts and so on. For the purposes of clarity, the fastenings in the housing <NUM> are not shown in <FIG>.

The housing <NUM> can comprise a unitary element surrounding the internal components of the power tool <NUM>. In other examples, the housing <NUM> can comprise one or more housing portions (not shown) which are mounted together to form the housing <NUM>. The housing <NUM> comprises one or more inner mechanisms <NUM> (as shown in <FIG>). The inner mechanism <NUM> is moveably mounted within the housing <NUM> and the inner mechanism <NUM> comprises one or more components operatively coupled to a tool holder <NUM>. The inner mechanism <NUM> is configured to move with respect to the housing <NUM> during operation. The inner mechanism <NUM> will be decoupled from the outer housing <NUM>. This means that the vibrations caused by the power tool <NUM> can be dampened. The inner mechanism <NUM> and its functionality will be described in more detail below.

As shown in <FIG>, the housing <NUM> comprises a primary handle <NUM>. Optionally a secondary handle (not shown) is also provided for the user to grip during use. Although not shown, optionally, the secondary handle may be mounted on a first side <NUM> of the housing <NUM> but alternatively the secondary handle can be mounted on at any location the housing <NUM>. A trigger button (not shown) is mounted on the primary handle <NUM> (or the secondary handle) which is used by the user to activate a motor assembly <NUM> (as shown in <FIG>).

Reference will now be made to <FIG> which shows a partial cut away side view of the power tool <NUM> according to an example. <FIG> shows the cut away section of the power tool <NUM> represented by the dotted box A in <FIG>. The cut away section as shown in <FIG> does not show part of the housing <NUM> for the purposes of clarity. The motor assembly <NUM> is electrically connected to a power source <NUM>. In some examples the power source <NUM> is a wired electrical connection to a main power supply. However in other examples, the power source <NUM> can be a battery pack (not shown).

As mentioned above, the inner mechanism <NUM> comprises the motor assembly <NUM>. In addition, the inner mechanism <NUM> also comprises a hammer assembly <NUM>. The motor assembly <NUM> comprises an electric motor <NUM> (best shown in <FIG>) which is operatively coupled to the hammer assembly <NUM>. The hammer assembly <NUM> is housed within a hammer assembly housing <NUM>. The hammer assembly <NUM> is coupled to the tool holder <NUM> (as shown in <FIG>). The hammer assembly <NUM> generates a reciprocating movement when the electric motor <NUM> is actuated. This causes the tool holder <NUM> and the tool to reciprocate. The hammer assembly <NUM> and the tool holder <NUM> are known and will not be described in further detail.

Similar to the hammer assembly <NUM>, the motor assembly <NUM> is housed within a motor housing <NUM>. The motor housing <NUM> is also shown in more detail in isolation in <FIG>. The motor housing <NUM> is coupled to the hammer assembly <NUM>. The motor housing <NUM> in some examples is fastened directly to the hammer assembly <NUM>. Additionally or alternatively the inner mechanism <NUM> optionally comprises a motor housing frame <NUM> for securing the motor assembly <NUM> and the hammer assembly <NUM>. The motor housing frame <NUM> can secure additional components thereto so that the inner mechanism <NUM> moves in unison during operation.

As shown in <FIG> and mentioned above, the electric motor <NUM> and the hammer assembly <NUM> are part of the inner mechanism <NUM> and are moveably mounted within the housing <NUM>. In this way, the hammer assembly <NUM> is arranged to reciprocate along a longitudinal axis B-B (as shown in <FIG>) of the power tool <NUM>.

The hammer assembly <NUM> is arranged to impart axial impacts onto a cutting tool (not shown) held in the tool holder <NUM>. In some examples, the cutting tool is a chisel bit for cutting stone, concrete, or other hard surfaces. In other examples, the cutting tool can be any other suitable cutting tool for cutting, marking, breaking, drilling a workpiece (not shown) as required. In some examples, the cutting tool comprises a longitudinal axis aligned with the longitudinal axis B-B of the power tool <NUM>.

<FIG> shows the inner mechanism <NUM> and that the inner mechanism <NUM> reciprocally moves within the housing <NUM> as shown by double ended arrow D. <FIG> shows a schematic cross-sectional view of the power tool <NUM> according to an example. <FIG> shows the fan <NUM> optionally mounted on the motor <NUM> so that the fan <NUM> a first side <NUM> of the fan <NUM> faces a first side <NUM> of the housing <NUM>. This will cause the direction of the airflow to flow from the air inlet <NUM> to the air outlet <NUM>. In other alternative examples, the fan <NUM> can be mounted upside down on the motor <NUM> such that the first side <NUM> of the fan <NUM> faces a second side <NUM> of the housing <NUM>. This will cause the direction of the airflow to flow from the air outlet <NUM> to the air inlet <NUM>. By mounting the fan <NUM> with different orientations with respect to the motor <NUM>, the direction of the airflow can be reversed to suit different housing structures.

When the hammer assembly <NUM> impacts the tool holder <NUM> and the cutting tool, vibrations and shocks are created in the power tool <NUM>. In order to prevent or limit excessive transmission of the vibrations to the housing <NUM> and the internal components of the power tool <NUM>, the power tool <NUM> comprises at least a first dampening system <NUM> (best shown in <FIG>).

The first dampening system <NUM> as shown in <FIG> will now be discussed further. The at least one first dampening system <NUM> comprises a compression spring <NUM> mounted between the inner mechanism <NUM> and the housing <NUM>. The compression spring <NUM> is arranged to be parallel with the longitudinal axis B-B of the power tool <NUM>. Accordingly, when the inner mechanism <NUM> moves with respect to the housing <NUM> in the direction along the longitudinal axis B-B, the inner mechanism <NUM> does not collide with the housing <NUM>. Furthermore, the compression spring <NUM> dampens most of the vibrations from the inner mechanism <NUM> due to inertia of the housing <NUM>. The at least one first dampening system <NUM> can optionally comprise additional compression springs <NUM>. Alternatively, or additionally, the at least one first dampening system <NUM> can optionally comprise other dampening components such as rubber dampers (not shown) mounted on the inner surface <NUM> of the housing <NUM>.

In some examples the power tool <NUM> comprises a first limitation system <NUM> configured to limit the extent of the axial movement of the inner mechanism <NUM> with respect to the housing <NUM>. The first limitation system <NUM> will now be discussed in reference to <FIG> and <FIG>. <FIG> shows a close-up partial perspective view of the inner mechanism <NUM> of the power tool <NUM> according to an example. <FIG> shows a close-up partial perspective view of the housing <NUM> of the power tool <NUM> according to an example.

The first limitation system <NUM> is mounted between the inner mechanism <NUM> and the housing <NUM>. In some examples, the first limitation system <NUM> comprises a plurality of components mounted at different locations around the inner mechanism <NUM>.

In some examples, the first limitation system <NUM> comprises a slider <NUM> mounted to the hammer assembly housing <NUM>. The slider <NUM> is elongate and configured to slide in a groove or reciprocal recess <NUM> (as shown in <FIG>) on the housing <NUM>. The reciprocal recess <NUM> is substantially the same width as the slider <NUM> and comprises a longer length than the slider <NUM>. This means that the slider <NUM> is permitted to slide within the reciprocal recess <NUM> from a first end <NUM> to a second end <NUM> of the reciprocal recess <NUM> in a constrained direction. As shown in <FIG>, the slider <NUM> is positioned at the first end <NUM> of the reciprocal recess <NUM>. When the power tool <NUM> is not actuated, the slider <NUM> will move to the first end <NUM> or the second end <NUM> depending on how the power tool <NUM> is orientated.

The limitation dampening system <NUM> in some examples provide axial limitations for the inner mechanism <NUM> and the housing <NUM> when the power tool <NUM> is in idle or too much force is applied to the housing <NUM> by the user. In the examples as shown in <FIG> and <FIG>, optionally the first limitation system <NUM> comprises limit stops e.g. the slider <NUM> abutting against the first end <NUM> or the second end <NUM> of the reciprocal recess <NUM>.

During operation, the slider <NUM> will maintain a position between the first and second ends <NUM>, <NUM> of the reciprocal recess <NUM>.

In some examples the slider <NUM> is a rubber or silicone material. The slider <NUM> and the reciprocal recess <NUM> are orientated along a longitudinal axis C-C. In some examples, the longitudinal axis of the slider <NUM> and the reciprocal recess <NUM> are parallel or substantially parallel with the longitudinal axis B-B of the power tool <NUM>. Accordingly, the first dampening system <NUM> is configured to prevent or limit vibration from the hammer assembly <NUM>.

<FIG> and <FIG> respectively show that the slider <NUM> and the reciprocal recess <NUM> are mounted on the inner mechanism <NUM> and the housing <NUM>. However, in some alternative examples, the slider <NUM> and the reciprocal recess <NUM> are respectively mounted on the housing <NUM> and the inner mechanism <NUM>.

During operation, the electric motor <NUM> may experience high load. This means that the electric motor <NUM> can heat up. In order to cool the electric motor <NUM> during operation the motor assembly <NUM> comprises a fan <NUM>. In some examples, the fan <NUM> is directly mounted to the shaft of the electric motor <NUM>. In some alternative examples (not shown) the fan <NUM> is operatively coupled to a gearbox (not shown). <FIG> only partially shows the fan <NUM> because the electric motor <NUM> and fan <NUM> are mounted within the motor housing <NUM>. <FIG> schematically represents the electric motor <NUM> and fan <NUM> assembled together. The electric motor <NUM> and the fan <NUM> together will be referred as the motor-fan assembly <NUM>.

The motor fan assembly <NUM> is configured to generate a cooling airflow path E from an air inlet <NUM> to an air outlet <NUM> via the motor fan assembly <NUM>. The cooling airflow path E is indicated by a dotted line and a series of arrows. In this way, the motor-fan assembly <NUM> is configured to draw cooling air from outside the power tool <NUM> to cool the electric motor <NUM> during operation. The air inlet <NUM> and the air outlet <NUM> are positioned at different locations on the housing <NUM>. In some examples the air inlet <NUM> is located on a first side <NUM> of the housing <NUM> and the air outlet <NUM> is located on a second side <NUM> of the housing <NUM>. In other examples, the air inlet <NUM> and the air outlet <NUM> can be located at any position in the housing <NUM> such that the cooling airflow path E is via the motor fan assembly <NUM>.

The cooling airflow path E as shown in <FIG> is exemplary and the cooling airflow path E can be any suitable path through the housing <NUM> from the air inlet <NUM> to the air outlet <NUM> via the motor fan assembly <NUM>. In some alternative examples, the airflow direction can be optionally inverted. The airflow direction can be inverted by mounted the fan <NUM> rotated by <NUM> degrees to the fan as shown in <FIG>. In this case, the air is drawn in via the air outlet <NUM> and exhaust at the air inlet <NUM>. Accordingly when the airflow direction is reversed, functionally the air inlet <NUM> will be an air outlet and the air outlet will be an air inlet.

The cooling airflow path E in some examples is guided within the housing <NUM> to the inner mechanism <NUM> via an internal wall <NUM>. The internal wall <NUM> is fixed with respect to the housing <NUM>. In this way, the inner mechanism <NUM> moves with respect to the internal wall <NUM>. Whilst <FIG> only shows one internal wall <NUM>, in other examples there can be any number of internal walls <NUM> to guide the cooling airflow path E through the housing <NUM>. The internal wall <NUM> comprises an air hole <NUM> such that the cooling airflow path E can flow through the motor fan assembly <NUM>.

Since the inner mechanism <NUM> moves with respect to the housing <NUM>, the cooling airflow path is guided towards the motor fan assembly <NUM>. The power tool <NUM> comprises at least one air conduit <NUM> located on the cooling airflow path E configured to guide the cooling airflow from the air inlet <NUM> to the motor fan assembly <NUM>. The air conduit <NUM> is a hollow structure configured to guide the cooling airflow within the housing <NUM>. The air conduit <NUM> can be rigid such as pipe structure or flexible such as a tubing, bellows, or sleeve structure. The air conduit <NUM> is any suitable structure for guiding the cooling airflow within the housing <NUM>.

The at least one air conduit <NUM> will now be described in more detail in reference to <FIG>. <FIG> and <FIG> show a close-up partial perspective views of the power tool <NUM> and the air conduit <NUM>. <FIG> shows an exploded perspective view of the motor housing <NUM> of the power tool <NUM>. <FIG>, <FIG> and <FIG> show a schematic cross-sectional view of the air conduit <NUM>.

Reference will now be made to <FIG>. The air conduit <NUM> comprises a first conduit end <NUM> and a second conduit end <NUM>. The air conduit <NUM> is mounted at the first conduit end <NUM> on a first end <NUM> of the motor housing <NUM> via a motor housing frame <NUM>. The motor housing frame <NUM> is fastened to the motor housing <NUM> via a plurality of fasteners e.g. screws <NUM>. The screws <NUM> are inserted through fastening holes <NUM> and into threaded bores <NUM> in the motor housing <NUM>.

Accordingly, the air conduit <NUM> is fixed to the motor housing <NUM> at the first conduit end <NUM>.

The air conduit <NUM> comprises a circumferential groove <NUM> configured to engage a circumferential rib portion <NUM> on the motor housing frame <NUM>. When the circumferential groove <NUM> is engaged with the circumferential rib portion <NUM> and the motor housing frame <NUM> is mounted to the motor housing <NUM>, the air conduit <NUM> is secured to the motor housing <NUM>. The circumferential groove <NUM> and the circumferential rib portion <NUM> can respectively be a single continuous circumferential groove <NUM> and a single continuous circumferential rib portion <NUM>. This may be advantageous because the air conduit <NUM> can be better sealed against the motor housing <NUM> at the first conduit end <NUM> of the air conduit <NUM>.

The circumferential groove <NUM> and the circumferential rib portion <NUM> can optionally respectively extend partially or fully around the air conduit <NUM> and the motor housing frame <NUM>. In some other examples, the circumferential groove <NUM> and the circumferential rib portion <NUM> comprise a plurality (not shown) of discrete circumferential grooves <NUM> and circumferential rib portions <NUM>.

This means that the motor housing <NUM> and the air conduit <NUM> are a unitary element and move together. Whilst <FIG> shows the air conduit <NUM> is mounted to the motor housing <NUM> via the motor housing frame <NUM>, the motor housing frame <NUM> is optional in some examples. In this case the air conduit <NUM> is mountable directly on the motor housing <NUM>. For example, the motor housing <NUM> comprises a circumferential rib portion <NUM> on which the circumferential groove <NUM> mounts.

In some other examples, the air conduit <NUM> is mountable to the motor housing <NUM> using other alternative fastenings. For example, the air conduit <NUM> is fastened to the motor housing <NUM> via screws <NUM>, glue, clips, clamps, bolts and so on. In some other examples, the air conduit <NUM> is overmolded on to the motor housing <NUM>. This means that the air conduit <NUM> can either be fixed directly to the motor housing <NUM> or fixedly indirectly via another component e.g. the motor housing frame <NUM>.

The motor housing <NUM> is hollow and generally cylindrical in shape. The walls of the motor housing <NUM> extend from the first end <NUM> to a second end <NUM>. The first end <NUM> and the second end <NUM> of the motor housing <NUM> is open and the motor housing <NUM> is configured to permit the cooling airflow therethrough. The motor housing <NUM> is configured to provide a circumferential void <NUM> between the electric motor <NUM> and the motor housing <NUM>. This means that the cooling airflow can flow over the electric motor <NUM> and remove heat from the electric motor <NUM> during operation.

In some examples the air conduit <NUM> is flexible. In some examples the air conduit <NUM> is resiliently flexible. The air conduit <NUM> is optionally made from a rubber rubber-like materials, thermoplastic elastomers (TPE), or silicone material. This means that the air conduit <NUM> can deform during operation of the power tool <NUM>.

Whilst the air conduit <NUM> as shown in the examples in the Figures is completely flexible, the air conduit <NUM> can be partially flexible (not shown) or completely rigid (not shown). In the example where the air conduit <NUM> is partially flexible, the air conduit <NUM> can comprise a rigid part and a flexible part. For example, the partially flexible air conduit <NUM> comprises a rigid pipe structure fixed to the motor housing <NUM> and a flexible sealing lip at one end (not shown) for engaging against part of the housing <NUM>.

As mentioned above. The air conduit <NUM> is fixed at the first conduit end <NUM> to the motor housing <NUM>. The second conduit end <NUM> is not fixed to any other elements of the power tool <NUM>. This means that the second conduit end <NUM> is a free end. This means that the second conduit end <NUM> and the air conduit <NUM> is configured to be moveable with respect to the housing <NUM>.

In some examples, the second conduit end <NUM> is configured to be slidably engageable with a portion of the housing <NUM>. <FIG> shows the second conduit end <NUM> of the air conduit <NUM> slidable engageable with an inner surface <NUM> of the internal wall <NUM>. It is preferred that the second conduit end <NUM> is in slidable engagement with the housing <NUM> because this provides a good seal and better guides the cooling air flow. However, in some less preferred examples, the second conduit end <NUM> of the air conduit <NUM> can be mounted adjacent to the portion of the housing <NUM> without touching the housing <NUM>. In this example, the cooling air flow will mostly be guided by the air conduit <NUM>, but some of the air within the housing <NUM> will be drawn into the motor fan assembly <NUM> and therefore the cooling effect will be lessened.

Whilst <FIG> shows that the air conduit <NUM> is slidably engageable with the internal wall <NUM>, in other examples the air conduit <NUM> is slidably engageable with an inner surface <NUM> of the housing <NUM>. In this case, the air conduit <NUM> will be moveably mounted in a location adjacent to air inlets <NUM>. Accordingly, the air conduit <NUM> as shown in <FIG> can be modified to extend further from the motor fan assembly <NUM> to the inner surface <NUM> of the housing <NUM>.

Turning back to <FIG>, in some examples, the second conduit end <NUM> of the air conduit <NUM> optionally comprises a curved lip <NUM>. The curved lip <NUM> allows for a good seal between the inner surface <NUM> of the internal wall <NUM> and the air conduit <NUM>. Furthermore, the curved lip <NUM> is configured to wipe the inner surface <NUM> of the internal wall <NUM>. This advantageously cleans dirt and debris from the inner surface <NUM> during operation. This means that the curved lip <NUM> can provide a good seal even when the worksite is very dirty. The curved lip <NUM> also prevents or limits warm air exhausted from the motor fan assembly <NUM> being recirculated through the motor fan assembly <NUM>. This improves the cooling effect of the cooling air flow.

Movement of the air conduit <NUM> will now be discussed in reference to <FIG>, <FIG>, <FIG> and <FIG>. <FIG> and <FIG> are close up views of the dotted box labeled F in <FIG>. The motor fan assembly <NUM> is partially shown in <FIG> and <FIG>. <FIG> shows the air conduit <NUM> in sliding engagement with the inner surface <NUM> of the internal wall <NUM> of the housing <NUM>. Part of the internal wall <NUM> has been removed in <FIG>.

The air conduit <NUM> as shown in <FIG> is in a first position. In the first position, the air conduit <NUM> is sealed against the inner surface <NUM> and the second conduit end <NUM> completely surrounds the air hole <NUM>. The first conduit end <NUM> as shown in <FIG> is connected to the motor housing <NUM>, but the motor housing <NUM> is not shown for the purposes of clarity. <FIG> also shows the air conduit <NUM> in the first position.

<FIG> shows that the diameter D1 of the air conduit <NUM> is greater than the diameter D2 of the air hole <NUM>. As mentioned above, this means that the air conduit <NUM> completely surrounds the air hole <NUM>.

<FIG> shows the air conduit <NUM> in sliding engagement with the inner surface <NUM> of the internal wall <NUM> of the housing <NUM>. Part of the internal wall <NUM> has also been removed in <FIG>. The air conduit <NUM> as shown in <FIG> is in a second position. In the second position, the air conduit <NUM> is sealed against the inner surface <NUM> and the second conduit end <NUM> completely surrounds the air hole <NUM>. The first conduit end <NUM> as shown in <FIG> is connected to the motor housing <NUM>, but the motor housing <NUM> is not shown for the purposes of clarity. <FIG> also shows the air conduit <NUM> in the second position.

As shown in <FIG> and <FIG> the air conduit <NUM> is moveable between the first and second positions by a travel distance D3. The diameter D1 of the air conduit <NUM> is greater than the diameter D2 of the air hole <NUM> and the travel distance D3. This means that the curved lip <NUM> of the second conduit end <NUM> is always in contact with the inner surface <NUM> of the internal wall <NUM>. Accordingly, as the air conduit <NUM> moves between the first and second positions as the inner mechanism <NUM> reciprocates during operation, the air conduit <NUM> maintains the seal.

During operation, the motor fan assembly <NUM> generates a negative pressure in the motor housing <NUM> and the air conduit <NUM>. This helps the air conduit <NUM> to seals against the inner surface <NUM> of the internal wall <NUM> during operation of the power tool <NUM>.

In some examples there are a plurality of air conduits <NUM> in fluid communication with the motor assembly <NUM>. Each of the air conduits <NUM> functions in the same way as previously described, except that the air conduit <NUM> is mounted between the inner mechanism <NUM> and the housing <NUM> on different sides.

In some examples the air conduit <NUM> is configured to reciprocate in a direction parallel or substantially parallel with the longitudinal axis B-B of the power tool <NUM>. By only moving in a direction parallel or substantially parallel with the longitudinal axis B-B of the power tool <NUM>, the circumferential groove <NUM> remains engaged with the circumferential lip <NUM>. This means that the air conduit <NUM> remains securely fastened to the motor housing <NUM>. In addition, the air conduit <NUM> does not undergo constant compression and extension during operation of the power tool <NUM>. This means that the air conduit <NUM> experiences less forces and experiences less wear and does not need to be made from a hard-wearing material.

Turning to <FIG> another example will now be discussed. <FIG> shows a schematic cross-sectional view of an air conduit <NUM>. The example shown in <FIG> is identical to the examples shown in the previous Figures (e.g. <FIG> and <FIG>) except that the air conduit <NUM> is fixed at the first conduit end <NUM> to the internal wall <NUM> of the housing <NUM>. Instead, the air conduit <NUM> comprises a second conduit end <NUM> which slidably engages with a motor housing surface <NUM>. The motor housing surface <NUM> is a protruding lip <NUM> formed on the first end <NUM> of the motor housing <NUM>. The second conduit end <NUM> slidably engages the motor housing surface <NUM> in the same way as discussed with respect to the previous examples. This means that the air conduit <NUM> seals against the motor assembly <NUM> and ensures that the cooling air flow is guided over the electric motor <NUM>. This means that the motor housing surface <NUM> is wiped by the air conduit <NUM> as the housing <NUM> and air conduit <NUM> move with respect to the inner mechanism <NUM>.

In another example, two or more examples are combined. Features of one example can be combined with features of other examples.

Claim 1:
A power tool comprising:
a housing (<NUM>);
an inner mechanism (<NUM>) mounted at least partially within the housing (<NUM>) and configured to be reciprocally moveable with respect to the housing (<NUM>), the inner mechanism (<NUM>) having a motor fan assembly (<NUM>);
an air inlet (<NUM>) and an air outlet (<NUM>) positioned in the housing (<NUM>) and a cooling airflow path extending between the air inlet (<NUM>) and the air outlet (<NUM>) via the motor fan assembly (<NUM>); and
at least one air conduit (<NUM>) located on the airflow path configured to guide the cooling airflow from the air inlet (<NUM>) to the motor fan assembly (<NUM>) wherein a first end (<NUM>) of the air conduit (<NUM>) is fixed and a second end (<NUM>) of the at least one air conduit (<NUM>) is a free end; wherein, either:
<NUM>) the first end (<NUM>) of the at least one air conduit (<NUM>) is fixed with respect to the motor fan assembly (<NUM>) and the second end (<NUM>) of the at least one air conduit (<NUM>) is moveable with respect to the housing (<NUM>); or
<NUM>) the first end (<NUM>) of the at least one air conduit (<NUM>) is fixed with respect to the internal wall (<NUM>) of the housing (<NUM>) and the second end (<NUM>) of the at least one air conduit (<NUM>) is moveable with respect to a motor housing surface (<NUM>) of the motor fan assembly (<NUM>);
characterised in that the second end (<NUM>;<NUM>) of the at least one air conduit (<NUM>; <NUM>) is slidably engageable with an inner surface (<NUM>) of the housing (<NUM>) or the motor housing surface (<NUM>).