GB2589550A

GB2589550A - Suction excavator with automatic hose rotation mechanism

Info

Publication number: GB2589550A
Application number: GB1914448.4A
Authority: GB
Inventors: Stock Jeff
Original assignee: Stock Excavators Ltd
Current assignee: Stock Excavators Ltd
Priority date: 2019-10-07
Filing date: 2019-10-07
Publication date: 2021-06-09
Also published as: GB201914448D0; WO2021069391A1; EP4041954A1

Abstract

Flexible hose 118 is mounted on the suction excavator vehicle 100. One end of the hose 118 is coupled to the debris collector 112 at a coupling 128. The hose 118 is supported by arm 122 and one or more brackets 124. The coupling 128 comprises an automatic rotation mechanism for turning the hose 118 around its axis, i.e. rotating the hose in a circumferential sense. The coupling 128 may operate as a rotary ratchet, which is configured to force the hose 118 to rotate with the lid section 130 in one direction, and permit relative rotation between the hose 118 and lid section 130 in the opposite direction. The coupling 128 may comprise a gear element and a pawl element, one of which is mounted on the hose 118 and the other of which is mounted on the lid section 130.

Description

SUCTION EXCAVATOR WITH AUTOMATIC HOSE ROTATION MECHANISM TECHNICAL FIELD

The invention relates to a suction excavator vehicle (sometimes referred to as a vacuum excavator) that operates to remove material or debris from an excavation site or a surface through a flexible suction hose. In particular, the invention concerns a mechanism for automatically rotating the flexible suction hose without having to detach it from the suction excavator vehicle.

BACKGROUND TO THE INVENTION

Many varieties of suction-type or vacuum-type vehicles exist for the purpose of excavating material from a hole, and/or for cleaning and removing dirt and debris from roads or paved surfaces. Typically, such vehicles comprise a debris collection mechanism mounted on a vehicle chassis, which is supported on a set of drivable wheels. The debris collection mechanism typically includes a flexible hose and a suction device. The suction excavator typically comprises a hydraulically-powered steering mechanism for manipulating the flexible hose. The suction device may comprise a fan driven to draw air along a flow path through the debris collection mechanism. The flow path includes the flexible hose, which operates to draw material into the debris collection mechanism. The debris collection mechanism typically includes a range of baffles and/or filters along the flow path to extract debris from the material drawn through the hose. The debris is typically deposited in a collection chamber housed on the vehicle.

The flexible hose is typically made of a heavy, durable material in order to ensure resilience to the debris (e.g. construction debris such as soil, gravel and crushed rock) which passes through the hose when in use. For example, the flexible hose may be made from rubber or heavy duty polyurethane having a sidewall thickness of around 6 mm, and in some examples may have metal nozzles or other metal components affixed thereto. The hose wall may be ribbed to facilitate bending.

It is known that flexible hoses of the type described above are susceptible to cracking after prolonged use in a certain orientation. This is caused by repeatedly application of stress to certain regions, which eventually leads to material fatigue and failure. To avoid this problem, users of such hoses are encouraged to regularly adjust the position of the hose, e.g. by rotating it around its axis, in order to avoid material fatigue from occurring rapidly at certain locations. Adjusting the position of the hose in this way helps to prolong the lifetime of the hose by reducing the chance of failure, such as cracking or breaking in the sidewall of the hose.

However, adjustment of the hose in conventional suction excavators is a time-consuming and laborious process. It typically requires the hose to be completely removed and remounted from the steering mechanism. This requires a team of maintenance workers and means that the suction excavator is not available for use for a prolonged period.

Two problems arise if a hose is not rotated as recommended, i.e. is subjected to many operations while held in the same position in the steering mechanism. Firstly, the risk of failure in normal use is increases (e.g. due to the regions of stress being concentrated in the same regions).

Secondly, it also increases the risk that the hose will fail (crack or break) when it is eventually rotated.

SUMMARY OF THE INVENTION

At its most general, the present invention provides an automatic hose rotation mechanism for a suction excavator. The rbLaLion mechanism operaLes Lo par Lially roLaLe Lhe flexible hose around its longitudinal axis during a normal operation cycle. This means that the hose is regularly rotated without having to detach it from the vehicle. The invention therefore reduces time required for vehicle maintenance (when the vehicle cannot be used), and increased the lifetime of the flexible hose.

According to the invention, there may thus be provided a suction excavator vehicle comprising: a chassis carried on a set of wheels; a debris suction mechanism supported on the chassis; and a flexible hose coupled at a first end thereof to the debris suction mechanism, wherein the debris suction mechanism is arranged to generate an air flow along a flow path between a suction intake element located at a second end of the hose and an exhaust outlet, whereby debris located around the suction intake element is entrained in the air flow, wherein the flexible hose is movable relative to the chassis to locate the suction intake element at an excavation site, and wherein the first end of the flexible hose is coupled to the debris suction mechanism by a rotation mechanism that is configured to rotate the first end of the flexible hose around its loncitudinal axis relative to the chassis.

By providing a rotation mechanism at the coupling between the flexible hose and the debris suction mechanism, the hose can be rotated in situ, i.e. without requiring the laborious disassembly required in conventional vehicles.

Herein, the term "suction excavator vehicle" may take its normal meaning, i.e. a construction vehicle adapted to remove material from holes or pits by application of a suction force. The debris suction mechanism may take any conventional form, but is preferably based on a fan (e.g. impeller) that is driven to generate a rapid air flow.

The flexible hose may also take any conventional form.

It may be formed from a resilient, durable (e.g. abrasion resistant) polymer material such as polyurethane. The hose may be reinforced, e.g. through the provision of a wire or other suitable reinforcing element in the hose wall.

The debris suction mechanism may comprise a lid section that is pivotable between a closed position in which it forms an upper surface of the vehicle and an open position for permiLLing removal of collecLed debris from wiLhin Lhe vehicle. The rotation mechanism may couple the first end of the flexible hose to the lid section. In this way, the pivot action of the lid section may cause the rotation of the flexible hose relative to the chassis. In one example, a pivot axis of the lid section runs along the vehicle (i.e. from front to back of the vehicle) along one side thereof, as is conventional.

The rotation mechanism may thus make use of the pivot action of the lid section, so that rotation of the hose become an integral part of each operational cycle of the vehicle. Herein, the term "operational cycle" may be used to mean each open-close cycle of the lid section. In other words, an operational cycle comprises a process of collecting debris with the lid section in the closed position (i.e. filling a collection chamber in the vehicle) followed by a process of removing the collected debris with the lid section in the open position (i.e. emptying the collection chamber) followed by closing the lid section so that the vehicle is ready for use again.

The rotation mechanism may be mounted in a position that aligns the longitudinal axis of the flexible hose (at its first end) with the pivot axis of the lid section. In this way, the rotation of the flexible hose may be directly linked to the pivoting of the lid section. However, the pivot axis and the longitudinal axis need not be identical.

In one example, the rotation mechanism may be configured to rotate the first end of the flexible hose when the lid section pivots from the closed position to the open position. The rotation mechanism may be configured to rotate the first end of the flexible hose through a predetermined angle for each operational cycle of the debris suction mechanism. The predetermined angle may have any value, but is preferably less than 90 degrees. This means that the rotation mechanism causes a full rotation of the hose to occur after a plurality of operational cycles. In order to ensure that the stresses on the flexible hose that are experienced in use are spread evenly over the hose, it may be desirable for the hose to perform a full rotation after 10 or more operational cycles, preferably 15 or more.

In one example, Lhe roLaLion mechanism may comprise a locking element mounted to the debris suction mechanism. The locking element may be selectively engagable with the flexible hose, e.g. under the action of an actuator. The actuator may be configured to selectively clamp the locking element to the flexible hose, and hence lock the flexible hose to the debris suction mechanism. The locking element may take any suitable form. For example, it may be a band (e.g. similar to a brake band) that encircles the flexible hose. In one example, the locking element may be mounted on the lid section. The locking element may engage the flexible hose (e.g. in a locked state) when the lid section is moved from an open position to a closed position to rotate the flexible hose relative to the chassis. The locking element may be disengaged (e.g. in an unlocked state) when the lid section is moved from a closed position to an open position to permit the flexible hose to remain stationary relative to the chassis.

In another example, the rotation mechanism may comprise a rotary ratchet configured to permit rotation of the first end of the flexible hose relative to the debris suction mechanism in a first direction, and inhibit rotation of the first end of the flexible hose relative to the debris suction mechanism in a second direction. With this arrangement, the rotation mechanism may be configured to permit relative rotation between the first end of the flexible hose and the lid section when the lid section pivots from the open position to the closed position. In other words, opening the lid section rotates the hose relative to the chassis, whereas closing the lid section does not affect the position of the hose relative to the chassis.

The rotary ratchet may be configured in a conventional manner. For example, it may comprise a gear element mounted on the first end of the flexible hose, and a pawl element mounted on the debris suction mechanism. The gear element and the pawl element may have any suitable configuration for achieving the effects set out above. For example, the gear element may comprises a plurality of radially protruding teeth extending outwardly from an outer surface of the flexible hose at the first end thereof. The pawl element may comprise one or more engaging features arranged to contact the teeth on the gear wheel.

In one example, Lhe roLaLion mechanism may comprise a sleeve arranged to receive the first end of the flexible hose.

Herein, the "first end" of the hose may refer to a length of the flexible hose located at or in the debris suction mechanism. The sleeve may be thus be arranged to receive a length of the flexible hose. The sleeve may be formed in or as part of the top section. The sleeve may comprise the pawl element of the rotary ratchet discussed above. For example, the sleeve may comprise one or more radially inwardly extending detents for engaging the teeth of the gear element. The one or more detents may be spring-loaded.

As mentioned above, the flexible hose is movable relative to the chassis to locate the suction intake element at an excavation site. The vehicle may comprise a steering mechanism attached to the flexible hose and arranged to control or otherwise effect movement of the flexible hose relative to the chassis. The steering mechanism may be configured to control the angle at which the flexible hose extends from the chassis, and may be configured to bend the flexible hose along its longitudinal axis. The steering mechanism may further comprise an extension mechanism for extending the flexible hose, i.e. varying its length in the longitudinal direction.

The steering mechanism may comprise an articulated arm.

The articulated arm may be operable manually or with mechanical assistance, e.g. using suitably configured hydraulics. The flexible hose may be retained on the articulated arm by one or more brackets.

To ensure that rotation of the hose is transmitted along its length from the first end, each of the one or more brackets may comprise a bearing to permit rotation of the flexible hose around its longitudinal axis relative to the articulated arm.

As mentioned above, the debris suction mechanism may comprise a collection chamber for receiving the entrained debris. When the lid section is in the open position, the collection chamber can be emptied. Emptying the collection chamber may include tipping it (pivoting it) relative to the chassis.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention is discussed below in more detail with reference to the accompanying drawings, in which: Fig. 1 is schematic side view of a suction excavator that is an embodiment of the invention; Fig. 2 is a rear view of the suction excavator of Fig. 1 with the debris collection mechanism in a closed position; Fig. 3 is a rear view of the suction excavator of Fig. 1 with the debris collection mechanism in an open position; Fig. 4 is a schematic cross-sectional view of one example of a hose rotation mechanism suitable for use in the invention; Fig. SA is a schematic cross-sectional view of another example of a hose rotation mechanism suitable for use in the invention, in an unlocked state; and Fig. 5B is a schematic cross-sectional view of the hose rotation mechanism of Fig. 5A in an unlocked state.

DETAILED DESCRIPTION; FURTHER OPTIONS AND PREFERENCES Fig. 1 shows a schematic side view of a suction excavator vehicle 100. To assist a description of the vehicle, the schematic view shows the vehicle as partially transparent. It can be in practice the operational components discussed below are hidden from view.

The suction excavator vehicle 100 is designed to remove material and debris from an excavation site, and may also be used to remove dirt, litter or debris from a road or paved surface. The suction excavator vehicle 100 comprises a chassis 102 supported by a pair of front wheels 104 and a pair of rear wheels 106. A driver cabin 168 is mounted on the chassis 102 over the front wheels 104. The vehicle engine (not shown) is located under the driver cabin 108 and has an engine exhaust 110 mounted on the chassis 162 behind the driver cabin 108.

Mounted on the chassis behind the engine exhaust 110 and driver cabin 108 is a debris suction mechanism 112.

A flexible hose 118 is mounted on the suction excavator vehicle 100. One end of the hose 118 is operably coupled to the debris collection mechanism 112 at a coupling 128. The other end of the hose 118 comprises a suction intake element 120 that opens into a passageway defined by the hose 118.

The hose 118 is mounLed Lo the vehicle by a sIeering mechanism, which in this embodiment comprises an articulated arm 122 which forms a boom for extending the hose away from the vehicle to an excavation site. The hose is connected to the articulated arm 122 by one or more brackets 124. The articulated arm 122 may be operated using hydraulic pistons 126, as is conventional. In other examples, the steering mechanism may be operating manually.

The steering mechanism allows movement of the hose 118 relative to the debris suction mechanism 112 so that an operator can move the suction intake element 120 to a suitable position for intake of debris.

The debris suction mechanism 112 comprises a fan that is rotatable in fan housing 116 under the action of an auxiliary engine and gearbox (not shown). In operation, the fan creates an air flow (indicated by dotted arrows in Fig. 1) through the hose 118 into a passageway 114 inside the debris suction mechanism 112. The passageway 114 in the debris suction mechanism 112 is configured to facilitate removal of debris from the air flow. For example, the passageway 114 may include one or more baffles 136 arranged to deflect the air flow as it exits the hose 11E. The baffles 136 may assist in separating larger pieces of debris 134 from the air flow.

Such debris 134 may be deposited in a collection chamber 132 mounted in the rear of the vehicle.

The passageway 114 may further include a wall 138 for diverting the air flow into a filter 140, e.g. a micromesh filter, that is arranged to remove smaller particles of debris (e.g. dust) from the air flow. These smaller particles of debris may settle into a container (not shown) at the base of the filter 140 for subsequent removal.

The fan for generating the air flow is located downstream from the baffle(s) 136 and filter 140 in order to ensure that the debris does not interfere with the fan. The fan housing 116 includes an annular air flow passage which circulates the air flow from an entrance inlet to an outlet. The entrance inlet is connected to receive air from the passageway 114 via a duct 142. The outlet is connected to an exhaust duct 144 that has an outlet port at the top of the vehicle. The configuration and operation of the fan may be conventional. The debris sucLion mechanism 112 comprises a lid secLion 130, which during operation is in a closed position in which it forms a top surface of the vehicle. However, as explained below, the lid section 130 is configured to pivot into an open position to allow removal of dirt and debris which has been collected by the suction excavator vehicle 100, e.g. in the collection chamber 132 or the filter 140.

The suction excavator vehicle 100 is thus configured to remove material and debris from an excavation site, and may also be used to remove dirt, litter or debris from a road or paved surface. When the collection chamber 132 is full, the collection chamber 132 is emptied or unloaded as described below with respect to Fig. 2.

The hose 118 may be of any conventional type. For example, it may have a diameter of at least 200 mm, for example 250 nm or 300 mm. The hose 118 may be made of a plastics material, such as polyurethane, having a wall diameter of 5 mm or more, for example. The suction intake element 120 may be the end of the hose 118, or may be an inlet through a nozzle which is attached at the end of the hose 118, for example.

The coupling 128 attaches the hose 118 to the lid section 130. As shown in Fig. 1, the coupling 128 may be at one end of the hose 118. However, in other examples, the hose 118 may include a proximal portion that extends inside the lid section 130. The coupling 128 may engage this proximal portion. As explained in more detail with reference to Fig. 4 below, the coupling 128 preferably comprises an automatic rotation mechanism for turning the hose 118 around its axis, i.e. rotating the hose in a circumferential sense. The coupling 128 may operate as a rotary ratchet, which is configured to force the hose 118 to rotate with the lid section 130 in one direction, and permit relative rotation between the hose 118 and lid section 130 in the opposite direction. For example, the coupling 128 may be configured to rotate the hose 118 when the lid section 130 is moved from the closed position to the open position. But, when the lid portion 130 subsequently returns to the closed position from the open position, the coupling 128 permit relative movement between the hose and the lid section 130. As a consequence of this action, the hose will have rotated relative to debris sucLion mechanism 112 by a cerLain amounL.

The coupling 128 may thus comprise a gear element and a pawl element, one of which is mounted on the hose 118 and the other of which is mounted on the lid section 130. In one example, the gear element is mounted on the hose 118, and the pawl is mounted on the lid section 130.

In order to transfer rotation of the proximal end of the hose 118 (i.e. the end attached to the debris suction mechanism 112 via the coupling 128) to the remaining length of the hose 118, the brackets 124 that attach the hose 118 to the steering mechanism may be configured to permit the hose 118 to rotationally slip within them. For example, the brackets 124 may have a low friction surface for abutting the hose into order to assist slippage. Alternatively, the brackets 124 may be provided with bearings to permit rotation of the hose 118 relative to the bracket. Rotation of the proximal end therefore results in rotation of the whole hose, without having to detach it from the steering mechanism. In other examples, the brackets 124 may not have bearings. Instead the brackets 124 may permit slippage of the hose or may be detached or loosened to permit relative rotation of the hose.

The rotary ratchet in the coupling 128 may be configured to rotate the hose through a predetermined angle upon each open-close cycle of the lid section 130. The predetermined angle is preferable acute, and may correspond to the angle that the lid section 130 subtends to the top surface of the vehicle in the open position. The predetermined angle may be selected to ensure that the hose fully rotates relative to the debris suction mechanism upon completion of a set number of open-close cycles of the lid section 130. The set number may be 5 or more, e.g. 10 or 15. In one example, the hose may fully rotate after 16 open-close cycle, i.e. the predetermined angle may be 22.5 degrees.

Fig. 2 shows a rear view of the suction excavator vehicle with the lid section 130 in a closed position, i.e. when the debris suction mechanism 112 is operational. The hose 118 is omitted for clarity, although the coupling 128 on the lid portion 130 is shown. Inside the debris suction mechanism 112, the collection chamber 132 is shown mounted on a base 148 and connected to an emptying mechanism 150 via a hydraulic cylinder 152. The chassis 162 also includes a pair of reLracLable supporL legs 146. In Fig. 2 Lhe supporL legs 146 are in a retracted position, which means that the vehicle 100 can be driven. Once in position, the support legs 146 may be deployed before use of the debris suction mechanism 112, e.g. before moving the hose 118 into position.

Fig. 3 shows a rear view of the suction excavator vehicle 100 in an unloading position. In order to unload or empty the collection chamber 132, the lid section 130 of the debris suction mechanism 112 is first opened upwards, pivoting on a suitable mounting element 153. The collection chamber 132 may them pivoted out of the vehicle by the emptying mechanism 150. As shown in Fig. 3, the collection chamber 132 is pushed by an extension of the hydraulic cylinder to pivot on the base 148.

The support legs 146 are shown in a deployed position in Fig. 3, in which they extend lower than the rear wheels 106.

Fig. 4 shows a schematic cross-sectional view through a coupling 128 that can be used as a hose rotation mechanism in embodiments of the present invention.

In this example, the coupling 128 comprises a coaxial arrangement in which a portion of the hose 118 fits within a sleeve 160 that is fixed to or formed integrally with the lid section 130. Thus, as the lid section 130 pivots, the sleeve 160 rotates relative to the rest of the vehicle (i.e. the rest of the debris suction mechanism 112). In one example, the sleeve 160 may have an longitudinal axis that is aligned with a pivot axis of the lid section 130. For example, as shown in Figs. 2 and 3, the pivot axis may run along one side of the lid section 130, and the coupling 128 may be mounted at that side, so that it aligns with the pivot axis. In other examples, however, the sleeve 160 need not be exactly aligned with the pivot axis. In such examples, the sleeve 160 may undergo a combination of relative translation and rotational motion relative to the rest of the vehicle. The present invention makes use of the rotational component of this relative motion.

Returning to Fig. 4, an inner surface of the hose 118 defines a passageway 154 for conveying debris. Meanwhile an outer surface of the hose 11E at the coupling 128 comprises a gear element, which in this example has a plurality of radially outwardly protruding teeth 156. The inner surface of the sleeve 162 at the coupling 128 comprises a pawl element, which in Lhis example comprises a pluraliLy of radially inwardly protruding detents 162. Although a plurality of detents 162 are shown in Fig. 4, the invention can be implement with any number, i.e. one or more.

The gear element and pawl element are configured to interengage as a rotary ratchet. The detents 162 inhibit rotation of the hose 118 relative to the sleeve 160 in a clockwise direction 166, whilst permitting rotation of the hose 118 relative to the sleeve 160 in a counterclockwise direction 164. In use, the ratchet operates such that the detents 162 drive rotation of the hose 118 in the counterclockwise direction 164 when the sleeve 160 rotates upon pivoting the lid section 130. When the lid section 130 pivots back such that the sleeve 160 rotates in the clockwise direction 166, the detents 162 slide over the teeth 156 such that the hose 118 remains substantially in the new rotated position while the sleeve 160 returns to its original (lid closed) position.

The gear element and pawl element may be configured in any manner to achieve the function described above. The shape and distribution of the teeth 156 and detents 162 need not be limited to that shown in Fig. 4. For example, the detents 162 may be spring-loaded.

The gear element and pawl element may be configured to cause the hose 118 to rotate by a predetermined angle for each open-close cycle of the lid section 130. The predetermined angle may be determined by a distribution of detents 162 on the pawl element and/or teeth 156 on the gear element.

Figs. 5A and 5B show schematic cross-sectional views of another example of a hose rotation mechanism that can be used in embodiments of the invention. Features in common with Fig. 4 are given the same reference number and are not described again.

Instead of the rotary ratchet shown in Fig. 4, the example shown in Figs. 5A and 5B uses a selectively operable locking element that can hold the hose 118 relative to the lid section 130. The locking element may take any suitable form. However, in this example, the locking element is a band 170, e.g. similar to a conventional brake band) that encircles the hose 118. The band 170 may be formed from a flexible material suitable that allows it to conform to the outer surface of the hose.

A first end of the band 170 is secured to a base 172. The base 172 may be fixed to the lid section 130, e.g. within the sleeve 160. A second end of the band 170 is secured to an actuator 174. The actuator 174 is movable, e.g. relative to the base 172 to move the band 170 between an unlocked state (shown in Fig. 5A) and a locked state (shown in Fig. 5B). In this example, the actuator 170 is a lever that pivots relative to the base 172. However, any actuator 174 that is configured to move relative to the lid section 130 may be used. The base 172 may include a drive mechanism configured to move the actuator 174. The drive mechanism may use pressurised air or hydraulics.

In the locked state, the band 170 is clamped around the hose 118. This means that the hose 118 will move with the lid section 130, e.g. as it is pivoted from the open position to the closed position. In contrast, in the unlocked state, the band 170 is loose around the hose 118, and therefore relative rotation between the hose 11E and the lid section 130 is permitted.

An advantage of this rotation mechanism is that the actuator 174 can be operated to control the extent of hose rotation. For example, the hose 118 may be put in the locked state for only part of the lid section's journey from the open position to the closed position.

Claims

CLAIMS1. A suction excavator vehicle comprising: a chassis carried on a set of wheels; a debris suction mechanism supported on the chassis; and a flexible hose coupled at a first end thereof to the debris suction mechanism, wherein the debris suction mechanism is arranged to generate an air flow along a flow path between a suction intake element located at a second end of the hose and an exhaust outlet, whereby debris located around the suction intake element is entrained in the air flow, wherein the flexible hose is movable relative to the chassis to locate the suction intake element at an excavation site, and wherein the first end of the flexible hose is coupled to the debris suction mechanism by a rotation mechanism that is configured to rotate the first end of the flexible hose around its longitudinal axis relative to the chassis.
2. A suction excavator vehicle according to claim 1, wherein the debris suction mechanism comprises a lid section that is pivotable between a closed position in which it forms an upper surface of the vehicle and an open position for permitting removal of collected debris from within the vehicle, and wherein the rotation mechanism couples the first end of the flexible hose to the lid section.
3. A suction excavator vehicle according to claim 2, wherein the rotation mechanism is configured to rotate the firsL end of Lhe flexible hose when Lhe lid secLion pivoLs from the closed position to the open position.
4. A suction excavator vehicle according to any preceding claim, wherein the rotation mechanism is configured to rotate the first end of the flexible hose through a predetermined angle for each operational cycle of the debris 43 suction mechanism.
5. A suction excavatcr vehicle according to claim 4, wherein the predetermined ancle is less than 90 degrees.
6. A suction excavator vehicle according to any preceding claim, wherein the rotation mechanism comprises: a locking element mounted on the debris suction mechanism; and an actuator configured to selectively clamp the locking element to the flexible hose.
7. A suction excavator vehicle according to claim 6, wherein the locking element is a band that encircles the flexible hose.
8. A suction excavator vehicle according to any one of claims 1 to 5, wherein the rotation mechanism comprises a rotary ratchet configured to permit rotation of the first end of the flexible hose relative to the debris suction mechanism in a first direction, and inhibit rotation of the first end of the flexible hose relative to the debris suction mechanism in a second direction.
9. A suction excavator vehicle according to claim 8, wherein the rotary ratchet comprises: a gear element mounted on the first end of the flexible hose, and a pawl element mounted on the debris suction mechanism.
10. A suction excavator vehicle according to any preceding claim, wherein the rotation mechanism comprises a sleeve arranged to receive the first end of the flexible hose.
11. A sucLion excavaLcr vehicle according Lo any preceding claim further comprising a steering mechanism attached to the flexible hose and arranged to move the flexible hose relative to the chassis.
12. A suction excavator vehicle according to claim 11, wherein the steering mechanism comprises an articulated arm, and wherein the flexible hose is retained on the articular arm by one or more brackets.
13. A suction excavator vehicle according to claim 12, wherein each of the one or more brackets comprises a bearing to permit rotation of the flexible hose around its longitudinal axis relative to the articulated arm.
14. A suction excavatcy vehicle according to any preceding claim, wherein the debris suction mechanism comprises a collection chamber for receiving the entrained debris.