Roll grooving tool

Abstract

An apparatus (1) arranged for rolling a circumferential external groove (994) in a pipe (99) The apparatus (1) comprises a fixture (50) and a grooving tool (10). In a fixing- position the fixture (50) is configured to engage an internal wall (996) of the pipe (99) and fix the apparatus (1) to a pipe end portion (990) such that a pipe centre axis (X99) is coaxial with an apparatus centre axis (X1), and the grooving tool (10) is rotatable around the centre axis (X1). The grooving tool (10) comprises a hydraulic piston (12) and at least one wheel-holder (110), the hydraulic piston (12) is displaceable along the centre axis (X1), the hydraulic piston (12) is configured to displace the wheel-holder (110) in a radial direction relative to the centre axis (X1) between an idle position (1102) and a grooving position (1104), and the wheel-holder (110) comprises a grooving wheel (111).

Description

[0001] ROLL GROOVING TOOL

[0002] This invention relates to a tool for grooving a pipe. More specifically the invention relates to a grooving apparatus arranged for rolling a circumferential external groove in a pipe end portion. The grooving apparatus forms a centre axis. The grooving apparatus comprises a fixture and a grooving tool. The fixture is configurable between a release-position and a fixing-position. In the fixing-position the fixture is configured to engage an internal wall of the pipe and fix the grooving apparatus to the pipe end portion such that a pipe centre axis is coaxial with the centre axis. The grooving tool is rotatable around the centre axis.

[0003] Background for the invention

[0004] To join pipes in an axial direction together and create a watertight joint, it is known to create a groove in each end of the pipes and connect the pipes with a metal joint which intervene with the grooves. A gasket is typically positioned between the pipes and the joint.

[0005] The groove is performed by turning the pipe inside a grooving tool, or turn the tool around the pipe, whilst one or more rollers apply a radial force to the outside of the pipe. The rollers inflict a radial deformation to the pipe so that a groove is formed in a periphery of the pipe, whilst an inner corresponding portion receives a protrusion.

[0006] Patent document GB2014072 discloses a stationary roll grooving tool including a pair of rolls rotatable about substantially parallel axes, one of the rolls being motor driven and the other freely rotatable. The driven roll is positioned inside a tube, whilst the freely rotatable roll is positioned outside. During the grooving process, the tube rotates around the driven roll, whilst the freely rotatable roll applies a deforming force on the outside of the tube.

[0007] Patent document JP2OOO21O723 discloses a grooving tool comprising multiple rollers providing the radial force to the pipe. This tool does not have an inner support.

[0008] Patent document EP1275447 discloses a portable roll groover where the grooving operation is performed manually by rotating a crank. In one embodiment, the pipe is a rigidly supported pipe so the portable roll groover rotates about the pipe. In an alternative embodiment the portable roll groover is rigidly fixed and the pipe to be grooved rotates relative thereto during the grooving operation.

[0009] Patent document W003089159 discloses an orbiting roller groover for pipes. The orbiting roller groover is mounted on a table and includes adjustments means for aligning the orbiting roller groover to the pipe.

[0010] Driven roll grooving tools by prior art have several disadvantages. Stationary tools requires that the pipes must be brought to the tool. This is time consuming and is often causing problems when working inside a building site, where long pipes must be brought through door openings and even from one floor to another floor. It is also a disadvantage that the pipe rotates. A rotating pipe requires extra support and must be secured against warp in case a centre axis for the pipe is not in line with the rotation axis for the pipe.

[0011] A disadvantage with a portable roll groover, is that it is heavy to use over time, and the centre of the crank is not in line with the centre of the pipe, meaning that the crank will rotate in a spiral. It also requires a solid fastening of the pipe, for instance by use of a vice.

[0012] The invention has for its object to remedy or to reduce at least one of the drawbacks of the prior art, or at least provide a useful alternative to prior art.

[0013] The object is achieved through features, which are specified in the description below and in the claims that follow. General description of the invention

[0014] The invention is defined by the independent patent claim. The dependent claims define advantageous embodiments of the invention.

[0015] In a first aspect the invention relates more particularly to a grooving apparatus arranged for rolling a circumferential external groove in a pipe end portion. The grooving apparatus forms a centre axis. The grooving apparatus comprises a fixture and a grooving tool. The fixture is configurable between a release-position and a fixing-position. In the fixingposition the fixture is configured to engage an internal wall of a pipe and fix the grooving apparatus to the pipe end portion such that a pipe centre axis is coaxial with the centre axis. The grooving tool is rotatable around the centre axis, and

[0016] - the grooving tool comprises a hydraulic piston and at least one wheel-holder;

[0017] - the hydraulic piston is displaceable in a direction along the centre axis;

[0018] - the hydraulic piston is configured to displace the wheel-holder in a radial direction relative to the centre axis between an idle position and a grooving position; and

[0019] - the wheel-holder comprises a grooving wheel.

[0020] The hydraulic piston may be displaceable parallel to the centre axis.

[0021] The pipe may be a sprinkler pipe made of metal. The grooving depth may be set by a stroke length of the hydraulic piston. The pipe wall thickness is typically 3-5 mm. An effect of the grooving tool rotating relatively to a housing and to the pipe, is that both the apparatus and the pipe are stationary, i.e. not rotating. Since the pipe is not rotating, there is no risk for warp, and grooving may also be done on a bended pipe. This makes the apparatus more flexible than a stationary grooving tool and improves the health and safety for an operator.

[0022] The grooving apparatus may be handheld and not fixed in a stationary setup. It is therefore beneficial to have a small outer dimension of the grooving apparatus. The hydraulic piston being displaceable along the centre axis enables a piston area without increasing the outer dimension of the grooving apparatus substantially. The hydraulic piston being displaceable along the centre axis may therefore be made compact and have a small out- er dimension. The piston area of the hydraulic piston being large creates several other effects that will be described. The hydraulic piston may be positioned within a cylinder bore. The cylinder bore may need to be filled with a hydraulic fluid to displace the hydraulic piston. Compared to a small piston area the large piston area needs more hydraulic fluid to displace the hydraulic piston a given distance. The larger fluid volume makes it easier to displace the piston in an even and consistent rate as a fluid flow may be kept higher for a given displacement rate. The wheel-holders may therefore be displaced at a controlled rate. Another effect is that a hydraulic pressure required to create a given piston force is reduced with a large piston area compared to a smaller piston area. This reduces the wear on a hydraulic pump supplying the hydraulic fluid and may reduce strain on internal components, e.g. the cylinder bore, etc.

[0023] The wheel-holder may comprise a grooving wheel. The grooving wheel may comprise a ridge and a smaller diameter on each side of the ridge. An effect of the smaller diameters on each side of the ridge is that the grooving depth may be set and limited by the smaller diameter engaging with the outer wall of the pipe. The grooving depth may be set with a combination of the stroke length of the hydraulic piston and the smaller diameter on each side of the ridge.

[0024] A large diameter grooving wheel will roll the circumferential external groove in the pipe end portion with less force compared to a small diameter grooving wheel. This is known for a person skilled in the art. The large piston area of the hydraulic piston displaceable along the centre axis enables larger grooving wheels within the wheel-holders without increasing the outer dimension of the grooving apparatus. The grooving apparatus may comprise a single hydraulic piston displaceable parallel to the centre axis or a plurality of hydraulic pistons displaceable along or parallel to the centre axis.

[0025] The hydraulic piston may be biased towards a starting position. The biasing means may be a single spring or a plurality of springs. The piston area being large enables the option of using larger springs compared to what a small piston area may enable. A larger and therefore more powerful spring may return the hydraulic piston back to the starting position at a higher rate compared to a weaker smaller spring. The grooving apparatus is therefore more efficient to use as the grooving wheels return to their starting position at the same time, and thereby the pipe is released from the grooving apparatus.

[0026] The hydraulic piston is configured to displace the wheel-holder in the radial direction relative to the centre axis between the idle position and the grooving position. In the idle position the hydraulic piston may be in the starting position and the grooving wheel may be positioned at a distance from the pipe, i.e. a clearance between the grooving wheel and the pipe. The wheel-holder may comprise a protrusion and the hydraulic piston may comprise a recess. The protrusion may be formed to be placed within the recess such that an axial displacement of the hydraulic piston creates a radial displacement of the wheelholder. The protrusion and the recess may form an angle with the centre axis such that the wheel-holder is displaced radially when the hydraulic piston is displaced parallel to the centre axis. It is apparent for a person skilled in the art that a plurality of alternative embodiments may be made for displacing the wheel-holder in the radial direction when the hydraulic piston is moved along or parallel to the centre axis. An example may be to have the protrusion in the hydraulic piston and the recess in the wheel-holder, etc.

[0027] In the grooving position the hydraulic piston has displaced such that the grooving wheel is abut the pipe and started to create the groove in the pipe. The grooving position may be a dynamic position where the wheel-holder displaces as the groove gets deeper and deeper.

[0028] In a preferred embodiment, the grooving tool may comprise at least three wheel-holders. Two grooving wheels may try to push the pipe out of centre if the two grooving wheels are not precisely aligned with the centre axis of the pipe. An advantage with three or more grooving wheels, is that three or more grooving wheels are self-centred. The wheelholders may therefore be displaced with a uniform rate such that radial forces are kept within the pipe and not absorbed by the fixture.

[0029] The grooving tool may comprise a base element and the wheel-holder may be radially displaceable connected to the base element. The base element may comprise a slot wherein a projection in the wheel-holder may displace within, in the radial direction. The base element may receive a rotational force and therefore transfer this rotational force to the wheel-holder attached to the base element. The hydraulic piston may be displaceable along or parallel to the centre axis relative to the base element. The base element may therefore be used to limit the stroke length of the hydraulic piston. The base element may be used as an opposing part for biasing the hydraulic piston back to the starting position. An effect of the mentioned technical features regarding the base element may be a compact design reducing a number of parts rotating relative to each other.

[0030] The base element may be used for routing a hydraulic fluid from the hydraulic pump to the cylinder bore.

[0031] The grooving apparatus may be configured to receive a rotational force from a drive shaft. The drive shaft may be offset from the centre axis The grooving apparatus may be configured to receive a hydraulic fluid from a pressure line. The drive shaft being offset may reduce the complexity in the fixture as the centre of the apparatus do not comprise a rotating member. Using the hydraulic fluid from a pressure line may reduce the strain for an operator to displace the hydraulic piston.

[0032] The drive shaft offset from the centre axis may transfer a rotational force to the grooving apparatus. The grooving tool may comprise an internal spur gear. The base element may be rotationally stiff connected to the internal spur gear. The drive shaft may therefore rotate the grooving tool with less complexity in the fixture compared to a drive shaft being coaxial with the centre axis.

[0033] The fixture may be configurable by displacing a shaft parallel to the centre axis. This enables to use fixtures similar to fixtures known in the art. By displacing the shaft, the activation of the fixture may be done at a remote location from where the grooving tool may rotate.

[0034] The rotational force and the hydraulic fluid flow may be provided by a battery powered power unit. The grooving apparatus and the power unit may be handheld. As the grooving apparatus may be made compact, the grooving apparatus and the power unit may be handheld. An effect of the grooving apparatus being handheld is that the grooving apparatus may be easier to properly align with the pipe, especially if the pipe is long. The grooving apparatus being handheld also enables the user to freely move between locations for where the grooving apparatus is needed. Using battery power for powering the grooving apparatus enables a user to move freely between locations without needing a power source at the different locations.

[0035] The grooving tool may comprise a visual indicator indicating a position of the hydraulic piston within the cylinder bore, thereby indicating the depth of the groove or an indication of when the groove is complete.

[0036] It is also described a hydraulic pump and drive mechanism which may be connectable to a power unit. The hydraulic pump and drive mechanism may comprise a hydraulic pump, a fluid reservoir and a pressure line. The hydraulic pump may be connected to the fluid reservoir and the pressure line. The hydraulic pump and drive mechanism may comprise a rotatable input shaft connectable to the power unit and configured to rotate the hydraulic pump. The hydraulic pump and drive mechanism may comprise a drive shaft configured to be rotated by the input shaft. The drive shaft may be off-set from the input shaft.

[0037] The beforementioned hydraulic pump and drive mechanism may be a first embodiment of the hydraulic pump and drive mechanism. The hydraulic pump and drive mechanism may be attached to an apparatus. The apparatus may have different specifications that need to be considered. Some apparatuses may need the power unit to be in-line with the apparatus. Other apparatuses may need the power unit to be angled such that the length of the hydraulic pump and drive mechanism assembled with the power unit is shorter.

[0038] In a second embodiment of the hydraulic pump and drive mechanism a position of the input shaft relative to the drive shaft may not be as important. The hydraulic pump and drive mechanism may be driven by a power unit, the hydraulic pump and drive mechanism may comprise a hydraulic pump, a fluid reservoir and a pressure line, the hydraulic pump may be connected to the fluid reservoir and the pressure line, wherein:

[0039] - a rotatable input shaft may be connectable to the power unit;

[0040] - the input shaft may be configured to rotate the hydraulic pump;

[0041] - the input shaft may be configured to rotate a drive shaft; and

[0042] - the hydraulic pump and drive mechanism may comprise an attachment portion in a dis- tai end opposite the input shaft, the attachment portion may form a centre axis and may comprise the drive shaft and the pressure line, the drive line may be offset from the centre axis.

[0043] In the second embodiment the input shaft may be offset from the drive shaft.

[0044] The description to follow is equally applicable for the beforementioned first and second embodiments of the hydraulic pump and drive mechanism.

[0045] The hydraulic pump and drive mechanism may be a part of a handheld apparatus. The rotatable input shaft may be connected to the power unit such that the power unit needs to be disassembled from the hydraulic pump and drive mechanism. The rotatable input shaft may be connected to the power unit by a quick connection such that the power unit may be used for other applications when the hydraulic pump and drive mechanism is not in use. The power unit may be battery operated. The power unit may be a handheld drill known in the art. An effect of this is that the hydraulic pump and drive may be configurable between a plurality of apparatuses and may easily be carried and used by a user.

[0046] The hydraulic pump and drive mechanism may be used for a variety of apparatuses using a hydraulic fluid flow and a rotational force. The variety of apparatuses may have different operational parameters. The operational parameters for the drive shaft may be a rotational speed and / or torque in the drive shaft. The operational parameter for the hydraulic pump may be a hydraulic flow and / or a hydraulic pressure which depends on a hydraulic pump specification. Therefore, the hydraulic pump and drive mechanism may be required to be configured such that one input shaft may meet both the operational parameter for the drive shaft and the hydraulic pump specifications. Different embodiments may be required depending on the operational parameter. Multiple embodiments will be described in the following.

[0047] One embodiment may be where the input shaft may connect to a through shaft or may be the through shaft in the hydraulic pump. The through shaft may be rotationally stiff connected to a spur gear that rotates a spur gear rotationally stiff connected to the drive shaft. The spur gears may be used to adapt the rotational speed and torque of the drive shaft such that the hydraulic pump may be rotated at a first rotational speed and at a first torque while the drive shaft is rotated at a second rotational speed and a second torque.

[0048] The drive shaft may be parallel to the input shaft. This enables to use spur gears for adapting the rotational speed and torque between the input shaft and the drive shaft while the drive shaft is being offset from the input shaft. The spur gears may also not adapt the rotational speed and torque, but rather just offset the drive shaft from the input shaft. The spur gears may be used to transfer the rotational force from the input shaft to a plurality of drive shafts. The hydraulic pump and drive mechanism may comprise two drive shafts, also referred to as a twin driveline. An advantage with a twin driveline is that the power can be distributed on two drive shafts with associated gears.

[0049] The hydraulic pump may be configured to rotate the drive shaft via a rotationally stiff connection between the hydraulic pump and the drive shaft. An effect of this is that the drive shaft may in this embodiment rotate at the same rotational speed as the hydraulic pump. The hydraulic pump and the drive mechanism may comprise a speed reduction gear and an intermediate shaft. The input shaft may comprise a first spur gear that rotates a second spur gear. The second spur gear may be rotational stiff connected to the intermediate shaft. The first and second spur gear may reduce the rotational speed of the intermediate shaft compared to the input shaft. The intermediate shaft may be rotation- ally stiff connected to the hydraulic pump and rotate the hydraulic pump. An effect of this is that the hydraulic pump may have a lower rotational speed compared to the input shaft. The term "rotationally stiff connected" is herein described as either two parts that may be disconnectable at some point in time, e.g. a threaded connection or a keyed connection, or the two parts may be permanently connected, e.g. welded connection or one part may be machined as a part of the other part. The intermediate shaft may for example be a shaft machined as a part of the second spur gear or the hydraulic pump.

[0050] In an alternative embodiment, the hydraulic pump may be an external gear pump. The external gear pump is known in the art. The intermediate shaft may be rotationally stiff fastened between a first pump-gear in the external gear pump and the speed reduction gear, and the drive shaft may be rotationally stiff connected to a second pump-gear in the external gear pump. An effect of this is that the external gear pump may be used to offset the drive shaft from the input shaft without using extra spur gears or have needlessly large spur gears. The configuration between the input shaft and the drive shaft is therefore compact enabling the hydraulic pump and drive mechanism to weigh less and be easier to handle.

[0051] The hydraulic pump and drive mechanism may comprise two external gear pumps. An effect of having two external gear pumps is that a hydraulic output may be doubled, an increased redundancy in the hydraulic system, or two individual hydraulic circuits may be formed. The two external gear pumps may each connect to one drive shaft such that there may be two drive shafts in the drive mechanism. The two external gear pumps may be configured in at least one of a parallel configuration and a serial configuration. An effect of the parallel configuration may be that the hydraulic fluid flow is increased compared to a single external gear pump. An effect of the serial configuration is that the hydraulic pressure may be increased compared to a single external gear pump.

[0052] The hydraulic pump and drive mechanism may comprise a lever. The lever may be configurable between an active position and a passive position. The lever may be used for enhancing safety when using the hydraulic pump and drive mechanism. This may be done by activating or deactivating parts of the hydraulic pump and drive mechanism and / or parts of a connected apparatus with the lever. The connected apparatus is an apparatus connected to the hydraulic pump and drive mechanism. In the passive position a pressure line may be connected to a fluid reservoir and in the active position the pressure line may be disconnected from the fluid reservoir. An effect of this is that the hydraulic pump is unable to create the hydraulic pressure in the passive position as the hydraulic fluid is routed to the fluid reservoir. In the active position the hydraulic pump may create the hydraulic fluid flow and the hydraulic pressure within the pressure line. The lever may be configured to displace a shaft in a direction parallel to the drive shaft between a first position and a second position. The lever positioned in the passive position configures the shaft to the first position. The lever positioned in the active position configures the shaft to the second position. The shaft may form a shaft axis. The shaft axis may be coaxial with the centre axis of the attachment portion. The drive shaft may be offset from the shaft. The shaft may be connected to the connected apparatus. The shaft in the second position may activate a feature of the connected apparatus. The shaft in the first position may deactivate the feature in the connected apparatus.

[0053] The lever may be a handle that may be turned around a pivot point, a slidable switch, or a pressable button.

[0054] The hydraulic pump and drive mechanism may be small and handheld. This may imply that the hydraulic pump and drive mechanism may be orientated in all possible directions. It is therefore beneficial to seal the fluid reservoir from a surrounding environment such that the fluid may not drip from a ventilation hole. As fluid is displaced from the hydraulic pump and into the connected apparatus, the volume of fluid within the fluid reservoir may change. This may need to be compensated for such that the hydraulic pump may operate according to the hydraulic pump specifications. The fluid reservoir may be connected to a volume compensation device. The fluid reservoir and the volume compensation device may come in many embodiments and will be described in more details later.

[0055] The pressure line may be connected to at least one of a relief valve and a flow restrictor. The pressure line may be a part of a hydraulic circuit. The hydraulic pump may provide the hydraulic fluid flow into the pressure line such that the hydraulic pressure may be created. An effect of the relief valve being connected to the pressure line is to ensure that the hydraulic pressure does not exceed a predetermined pressure. This is a safety feature. An effect of the pressure line being connected to a flow restrictor is to be able to set the hydraulic fluid flow from the hydraulic pump to a predetermined flowrate. This may improve the operation of the connected apparatus.

[0056] The hydraulic pump and drive mechanism may be configured to be connected to a rotatable apparatus. The hydraulic pump may be connected to the rotatable apparatus via one or more hydraulic lines. The shaft may be connected to the rotatable apparatus. The drive shaft may be connected to the rotatable device and transfer a rotational force to the rotatable apparatus. The rotatable apparatus may be a grooving apparatus. It is also described a rigid fluid reservoir for a hydraulic fluid, the rigid fluid reservoir may comprise a rigid house and an outlet, wherein:

[0057] - the rigid fluid reservoir may be sealed from a surrounding environment;

[0058] - the rigid fluid reservoir may comprise an inflatable device, the inflatable device may be positioned within the rigid house; and

[0059] - the inflatable device may communicate with the surrounding environment via a through hole in the rigid house.

[0060] The through hole may be a hole through a wall forming the rigid house.

[0061] The fluid may be an oil used in hydraulic applications.

[0062] An effect of the rigid fluid reservoir being sealed from the surrounding environment is that the rigid fluid reservoir may be placed in any orientation without leaking from a ventilation hole. This may be very beneficial if the rigid fluid reservoir is to be connected to or be part of a handheld apparatus. The inflatable device may inflate or deflate depending on if fluid is drawn from the rigid fluid reservoir or if fluid is fed into the rigid fluid reservoir. The inflatable device therefore provides volume compensation.

[0063] When the fluid is drawn from the rigid fluid reservoir or returned to the rigid fluid reservoir, the inflatable device inflates or deflates, respectively. To inflate the inflatable device, air from the surrounding environment is drawn into the inflatable device. To deflate the inflatable device, air is evacuated from the inflatable device to the air surrounding the rigid fluid reservoir. The inflation and deflation occur due to a pressure difference created by fluid being drawn from or returned into the rigid house. An effect of using air from the surrounding environment to inflate or deflate the inflatable device is reduced complexity by not having the inflatable device inflated to a predetermined pressure.

[0064] The air being drawn into the inflatable device from the surrounding environment may be contaminated causing a build-up of debris within the inflatable device over time. The through hole may be positioned within an outer cover. An effect of this is that there may be a barrier between the inflatable device and the debris in the air in the surrounding environment. The outer cover may be a filter or a mesh. The outer cover may be a part of an apparatus.

[0065] The inflatable device may comprise a flexible material. The inflatable device may be a bladder or a balloon. The inflatable device may comprise a metal bellow.

[0066] It is beneficial to have the rigid fluid reservoir as compact in size as possible if it is to be used with a handheld apparatus. The inflatable device may comprise a longitudinal axis. The longitudinal axis may be from the through hole to a distal opposite end of the inflatable device. The inflatable device may expand along the longitudinal axis. The longitudinal axis may be parallel to a shaft. The shaft may be positioned to extend from within the rigid fluid reservoir to an apparatus outside the rigid fluid reservoir. The shaft may extend through the rigid fluid reservoir.

[0067] The rigid fluid reservoir may be a part of a hydraulic pump and drive mechanism.

[0068] In a second aspect the invention relates more particularly to a grooving system arranged for rolling a circumferential external groove in a pipe end portion, wherein:

[0069] - the grooving system comprises a grooving apparatus according to the first aspect of the invention;

[0070] - the grooving system comprises a hydraulic pump and drive mechanism, a fluid reservoir, and a fixture;

[0071] - the hydraulic pump and drive mechanism is configured to connect to a power unit and receive a rotational force from the power unit via an input shaft;

[0072] - the hydraulic pump and drive mechanism is configured to create an output, the output comprises a hydraulic fluid flow and a rotational force, the output is transferred to the grooving apparatus;

[0073] - the fixture forms a fixture centre axis coaxial with a grooving tool centre axis;

[0074] - the fixture is configured for engaging an internal wall of a pipe and fix a pipe end portion to the grooving apparatus.

[0075] The hydraulic pump and drive mechanism may be connected to the grooving apparatus such that a drive shaft and a hydraulic circuit may transfer forces to a grooving tool within the grooving apparatus. The fixture may be configurable via a lever in the hydraulic pump and drive mechanism.

[0076] The hydraulic pump and drive mechanism may comprise means for increasing a torque and reducing a rotational speed from the power unit to the grooving tool. An effect of this is that the rotational speed (rounds per minute - rpm) and torque from the power unit may be adjusted to give a correct rpm and torque for the grooving tool. The rotational speed of a power unit like a handheld drill connected to the apparatus is typically 600-700 rpm. The rotational speed of the grooving tool is typically 60 rpm. Consequently, the hydraulic pump and drive mechanism may be arranged to reduce the rpm by about 85-90 %. The gear ratio adjustment can be done with gears. The gear ratio adjustment can be done with a belt or a chain. The gear ratio adjustment can be done in one or more steps.

[0077] The hydraulic pump and drive mechanism may comprise at least one drive shaft positioned offset from the centre axis of the grooving tool. An effect of this is that the fixture may be less complicated as the drive shaft is offset from the fixture centre axis. The hydraulic pump and drive mechanism may comprise two drive shaft that is offset from the fixture centre axis. This is referred to as a twin driveline. An advantage with the twin driveline is that the power can be distributed on two drive shafts with associated gears.

[0078] The drive shaft may in a first end be connected to a set of gears arranged to transfer power from an input drive shaft to the drive shaft being offset from the grooving tool centre axis. The drive shaft may in a second end be connected to an internal spur gear with internal toothing. An effect of the internal toothing is that the drive shaft may be positioned closer to the grooving tool centre axis compared to an embodiment where the ring gear has an external toothing. This makes the grooving system more compact.

[0079] The hydraulic pump and drive mechanism may comprise a set of gears arranged to transfer power from the input shaft to one or more drive shaft offset from the grooving tool centre axis.

[0080] The fixture may comprise a plurality of segments being radially displaceable by means of an eccentric coupling connected to a shaft. The shaft may be displaceable along the fix- ture centre axis. The fixture may comprise multiple segments being connected to a corresponding number of cones being connected to the shaft. When the shaft is displaced in a direction along the fixture centre axis, the cones will lead the segments in a radial direction, outwards or inwards. In a preferred embodiment the fixture may comprise three or more segments, since three or more segments are self-centric versus the pipe.

[0081] The eccentric coupling may be operated by a lever. The lever may be accessible externally. An effect of this is that the lever enables a larger torque for displacing the eccentric coupling than for instance a small screw or a button. To achieve the corresponding torque with a screw, the screw must have the same radius as the length of the lever. A lever also visualizes the position of the eccentric coupling very well. If an axial displacement of the eccentric coupling equals a 180 degrees rotation of a shaft serving the eccentric coupling, the position of the lever clearly indicates the position of the eccentric coupling thereby enabling the user to check a configuration of the fixture.

[0082] The grooving system may further comprise a lever lock to prevent unintentional disengagement of the fixture from the internal wall of the pipe.

[0083] The grooving system may be configured to be handheld. By handheld is herein understood that the grooving system and / or the power unit are designed to be held by one hand. The grooving system may have a net weight about 3-10 kg.

[0084] The power unit may be an electric motor. The power unit may be a handheld drill, possibly a standardized drill. An effect of being handheld, is that the grooving system may be moved to the pipe, and that a grooving operation can be performed on a mounted pipe. The space needed to perform the grooving equals the size of the grooving system. The invention described herein offer a far more flexible and efficient grooving operation compared to prior art stationary grooving tools and manual grooving tools.

[0085] It is also described a method for creating a groove in a pipe, where the method comprises the steps of: providing a grooving system according to the second aspect of the invention; setting the lever in a passive position; positioning the apparatus at an end of a pipe; setting the lever to the active position such that the fixture fastens the grooving apparatus to the end of the pipe; activating the power unit to rotate the wheel-holders about the end of the pipe while the hydraulic piston moves the wheel-holders from an idle position to a grooving position; and continuing the rotation of the wheel-holders about the end of the pipe to complete the groove.

[0086] It is also described a fixture for engaging an internal wall of a pipe end portion and fix the pipe end portion to an apparatus, the fixture may comprise:

[0087] - a shaft forming a longitudinal axis coaxial with a centre axis of the apparatus, the shaft being axially displaceable along the axis in a DI direction and an opposite D2 direction,

[0088] - a plurality of segments, each segment being radially displaceable between a releaseposition and a fixing-position, each segment comprises a wedge shaped inner face and an outwardly facing holding face;

[0089] - a cone comprising a tapered wedge face abutting the wedge shaped inner face, the cone being engaged with the shaft; and

[0090] - a release spring element biasing the segments in the axial direction towards the releaseposition, such that an axial displacement of the cone relative to the segments in the DI direction may displace the segments radially outwards towards the internal wall, and an axial displacement of the cone relative to the segments in the D2 direction may displace the segments radially inwards towards the centre axis.

[0091] The cone may comprise a cone centre hole and the cone may be slideably engaged with the shaft in the cone centre hole, and the fixture may comprise a position spring element, the position spring element may abut the cone and may bias the cone axially in the DI direction.

[0092] The pipe end portion may form a pipe centre axis. The apparatus may form an apparatus centre axis. The fixture may be configured to fix the pipe end portion to the apparatus such that the fixture centre axis may be coaxial with the pipe centre axis and the apparatus centre axis.

[0093] When the shaft is displaced in the DI direction, the segments engage with the internal wall of the pipe and the fixture is in an active position / fixing-position. When the shaft is displaced in the D2 direction, the segments disengage with the internal wall of the pipe and the fixture is in a passive position / release-position.

[0094] The fixture may be configured to radially displace the segments outwards between the release-position and the fixing-position. The segments may comprise of a rigid material. The segments may comprise of a gripping surface configured to grip the internal wall of the pipe. The gripping surface may comprise a grooved surface, a cogged surface, or a serrated surface. A radial force may be used for displacing the segments radially and to engage the internal wall such that the pipe end portion is fixed to the apparatus. When the segments are displaced radially from the release-position to the fixing-position a gap may form between the segments due to the radial displacement. If the radial force is large compared to a thickness of the pipe, the pipe may be deformed and form a noncircular shape. E.g., a fixture comprising two segments may form an oval pipe, i.e. a pipe with two bulges, a fixture comprising three segments may form a pipe with three bulges etc.

[0095] Using a cone to displace the segments radially enables the cone to take advantage of a mechanical advantage associated with wedges. This may reduce an axial force required to safely fix the end portion of the pipe to the apparatus.

[0096] The gripping surface of the segment may be part of a full circle in the fixing-position, and the fixing-position positions the segments to form an imaginary circumference that is circular to engage the internal wall of the pipe. The imaginary circumference of the segments may be similar or substantially similar to an internal circumference of the wall of the pipe. An effect of the segments forming the imaginary circumference that is circular is that the deformation of the pipe is kept to a minimum when the fixture engages the internal wall of the pipe. This is important when cutting or forming the outer circumference of the pipe near the end portion of the pipe while the fixture fixes the pipe end portion. The release-position may position the segments to form a release imaginary circumference, the release imaginary circumference may form a non-uniform circular circumference. The non-uniform circular circumference may be formed by a ridge near a centre position on the outer surface of each segment. Each ridge may have a trough on each side. A greater clearance gap may be formed between the internal wall of the pipe and the trough when the segments are in the release-position. The greater clearance gap may make it easier to disengage the segments from the internal wall of the pipe compared to a circular circumference as the troughs may enable the pipe to be wiggled away from the segments.

[0097] A lever may be configured to displace the shaft. The lever may have a passive position and an active position, wherein the lever may be locked in the active position by a lever lock. Locking the lever in the active position ensures that the lever remains in the active position. This may be important such that the fixture do not accidentally release the pipe while for example forming the outer circumference of the pipe with a groove. The shaft in the fixing-position may be configured to enable the apparatus to operate. The shaft in the fixing-position may for example connect a hydraulic line between a hydraulic pump and the apparatus. In the release-position the hydraulic line between the hydraulic pump and the apparatus may be disconnected. This enhances safety as the apparatus may not be activated before the shaft is in the active position and the pipe is fixed to the apparatus.

[0098] The shaft may comprise a cone shoulder and the position spring element may bias the cone such that the cone may abut the cone shoulder in the release-position.

[0099] The fixture may comprise a first spring housing fastened to the shaft, and the release spring element may be biased between the segments and the first spring housing.

[0100] The segments may be biased towards the release-position by the release spring element. An effect of this is that the segments retract with minimum effort from the user as a retraction force comes from the release spring element. An interface between the segments and the adjacent parts may be less complex as the release spring element may position the segments in a fixed position along the centre axis. The release spring element may be a coil spring. In large scale production of pipes, the diameter of the internal wall of the pipe may have variations. In an embodiment where the lever is configured to displace the cone and therefore the segments to the fixing-position a variation in the diameter of the internal wall may prevent the lever from reaching the lever lock. The fixture may comprise a first spring housing fastened to the shaft, and the position spring element may be biased between the cone and the first spring housing. The position spring element may bias the cone such that the segments are biased towards the fixing-position. An effect of this is that the cone is allowed an axial flexibility and therefore the segments have some radial flexibility in the fixing-position. The flexibility allows for variations in the diameter of the internal wall while the lever is locked in the active position. The position spring element may be a single disc spring or a plurality of stacked disc springs.

[0101] An outer surface of the segment may comprise a receiving indentation. The indentation may be positioned to align with for example a grooving apparatus configured to form a groove around the circumference of the pipe. A bump may be formed on the inside of the pipe when a grooving wheel is pressed against the outer surface of the pipe to form the groove. The indentation allows the groove to be formed without deforming the segments or increasing a force required to create the groove.

[0102] The apparatus may be a grooving apparatus. The apparatus may be other apparatuses that may need the fixture for engaging the internal wall of a pipe.

[0103] In the following is described an example of a preferred embodiment illustrated in the accompanying drawings, wherein:

[0104] Fig. 1 shows in perspective a grooving apparatus connected to a handheld drill;

[0105] Fig. 2 shows in perspective an inside of the grooving apparatus from a right-hand side;

[0106] Fig. 3 shows an axial section view along A-A of the grooving apparatus;

[0107] Fig. 4 shows an axial section view along B-B of the grooving apparatus;

[0108] Fig. 5 shows an axial section view along C-C of the grooving apparatus; Fig. 6 shows a section view along D-D of the grooving apparatus;

[0109] Figs. 7a-c show details of a wheel-holder, a base plate and a ring-shaped hydraulic piston;

[0110] Fig. 8 shows an axial section view along E-E of the grooving apparatus;

[0111] Figs. 9a-b show in a different scale a cross section view along F-F and G-G of the grooving apparatus;

[0112] Fig. 10 shows in a different scale an exploded view of a shaft and a fixture;

[0113] Fig. 11 shows in a different scale an axial section view of the shaft and the fixture;

[0114] Fig. 12 shows a section view along H-H of the fixture; and

[0115] Fig. 13 shows an enlarged view of a detail of the fixture when a cone has slid along the shaft.

[0116] To focus on the invention, it should be clear that elements as seals, screws, bolts, nuts, bearings and bushings may not be numbered. It should also be clear that all rotating parts may be supported by one or more bearings, radially and / or axially. By bearing is herein understood any element arranged to reduce friction for a rotatable part.

[0117] Figure 1 shows a grooving apparatus 1 connected to a power unit 9 via a coupling 480. The power unit 9 is shown as a handheld drill 90. The coupling 480 is formed to fit a standard handheld drill 90. A grooving apparatus centre axis is indicated by the referral numeral XI. The grooving apparatus 1 and the drill 90 as illustrated may be operated with one hand only or by two hands. The illustrated grooving apparatus 1 comprises a grooving tool 10, a hydraulic pump and drive mechanism 20, and a fixture 50. A hydraulic pump housing 60 comprises a first house part 601 and a second house part 602. A lever 550 is positioned outside a housing 40. The lever 550 is in the passive position 5502. By turning the lever 550 180 degrees, the lever 550 may be locked in an active position 5504 (best seen in figure 2) by a lever lock 560. Referring to figures 2 and 4. An input shaft 200 is arranged for being connected with the handheld drill 90. The input shaft 200 is connected to a first spur wheel 201 of a dual spur gear 21. The dual spur gear 21 comprises two second spur wheels 202, each in engagement with the first spur wheel 201. Each second spur wheel 202 is rotationally stiff fastened to a respective intermediate shaft 202a. In the illustrated embodiment, the second spur wheel 202 is a speed reduction gear as the second spur wheel 202 has more teeth than the first gear 201. A third spur wheel 203 is rotationally stiff fastened to the intermediate shaft 202a. The third spur wheel 203 is engaging a fourth spur wheel 204. The fourth spur wheel 204 is rotational stiff fastened to a first end 208 of a drive shaft 207. The drive shaft 207 is offset from the grooving apparatus centre axis XI. A fifth spur wheel 205 is rotationally stiff fastened to a second end 209 of the drive shaft 207. The fifth spur wheel 205 engages with internal teeth of an internal spur gear 206. The internal spur gear 206 is rotationally stiff fastened to a base element 120. In the illustrated embodiment the input shaft 200 is coaxial with the grooving apparatus centre axis XI, however this is not required for the grooving apparatus 1 to function.

[0118] The hydraulic pump and drive mechanism 20 is illustrated as a twin driveline, meaning that the torque is transferred from the drill 90 to the grooving tool 10 by two drive shafts 207. An alternative embodiment (not shown) may have a single drive shaft 207 or more than two drive shafts 207.

[0119] The lever 550 is locked by the lever lock 560 in the active position 5504. The lever 550 is connected to an eccentric coupling 552.

[0120] Figure 3 shows the lever 550 is in a passive position 5502 opposite of the active position 5504 (as seen in figure 2). The shaft 520 is displaceable along the grooving apparatus centre axis XI between a first position 5202 (as seen in figure 3) and a second position 5204 (as seen in figure 8) by turning the lever 550. The lever 550 and the shaft 520 are connected via the eccentric coupling 552. When the lever 550 is turned to the passive position 5502, the eccentric coupling 552 displaces the shaft 520 in a second direction D2 to the first position 5202. The lever 550 is now in the passive position 5502 and the shaft 520 is in the first position 5202. When the lever 550 is reversed, i.e. turned to the active position 5504, the eccentric coupling 552 displaces the shaft 520 in a first direction DI to the second position 5204. The lever 550 is then in an active position 5504 and the shaft 520 is in the second position 5204.

[0121] Referring to figures 2, 3 and 8-13. A fixture 50 is arranged to lock a pipe end portion 990 of a pipe 99 to the apparatus 1. A pipe centre axis is identified by the numeral X99. The illustrated fixture 50 comprises three segments 510 arranged for a locking engagement with an internal wall 996 of the pipe 99 in a radial direction.

[0122] The fixture 50 and the shaft 520 is best shown in figures 10 and 11. The shaft 520 comprises in one end a coupling portion 5200 and in an opposite end a fixture portion 5209. From the coupling portion 5200 towards the fixture portion 5209, the shaft 520 comprises a coupling head 5201, a hydraulic section 521, a cone section 523, a spring section 525, and a threaded section 527.

[0123] The diameter of the cone section 523 is less than the diameter of hydraulic section 521. A cone shoulder 522 is formed between the hydraulic section 521 and the cone section 523. The cone section 523 may have an un-round shape, such as a polygonal geometry, or being splined. The cone section 523 may comprise a key or a ridge. In figures 10 and 12 the cone section 523 is depicted with a polygonal geometry, i.e. a hexagonal geometry.

[0124] The diameter of the spring section 525 is less than the diameter of cone section 523. A spring shoulder 524 is formed between the cone section 523 and the spring section 525.

[0125] The threaded section 527 may be of the same diameter as the spring section 523 or may be of a less diameter than the spring section 523.

[0126] The coupling head 5201 comprises a through hole 5203 adapted to receive the eccentric coupling 552 as described previously.

[0127] A pipe stopper disc 530 has a centre portion 531 with a centre through opening 532. A segment face 533 circumferences the centre portion 531. A rim flange 534 circumferences the segment face 533. The centre portion 531 is off set the segment face 533 to form a cone indentation 535. The centre through opening 532 has a diameter large enough to let the shaft 520 pass through. The segment face 533 is closer to the threaded section 527 than the centre portion 531.

[0128] A cone 512 comprises a centre cone hole 5123 which matches the geometry of the cone section 523. The cone 512 is slideably engaged with the shaft 520. The cone 512 comprises on the outside tapered wedge faces 5121. Figures 10 and 12 depict three wedge faces

[0129] 5121. The wedge faces 5121 taper towards the coupling portion 5200. The cone 512 has a smallest diameter towards the pipe stopper disc 530 and the smallest diameter of the cone 512 fits into the centre portion 531 as seen in figures 4, 8 and 13. Each wedge face 5121 is provided with an outward projecting guide 5122 in a longitudinal direction. The guide 5122 is shown as a T-shaped guide 5124 as depicted in figures 10 and 12. The longitudinal length of the cone 522 corresponds to the length of the cone section 523.

[0130] Each wedge face 5121 and corresponding guide 5122, 5124 mates with a segment 510. Each segment 510 is sector shaped with an arc shaped outer surface 511 and a wedge- shaped inner surface 517. The arc shaped outer surface 511 comprises a receiving indentation 515 and a holding face 516. The holding face 516 is shown as rough holding face 516 for better grip. The holding face 516 has a larger diameter than the receiving indentation 515 and the outer surface 511 is stepped. The wedge-shaped inner surface 517 tapers towards the threaded section 527. The wedge-shaped inner surface 517 comprises in the longitudinal direction a slit 5172 which mates with the outward projecting guide

[0131] 5122. The slit 5172 may be a T-shaped slit 5174 which mates with the T-shaped guide 5124 (see figure 12). A relative movement of the segment 510 along the longitudinal direction of the cone 512 provides for a radial movement of the segment 510.

[0132] A second spring housing 518 surrounds the shaft 520. The spring housing 518 is provided with an inward projecting rim 5181 which form a centre housing hole 5183. The rim 5181 abuts a segment end face 5109 of the segment 510 as seen in figure 11. The centre housing hole 5183 has a diameter that allows for passage of a cone end face 5129 into the spring housing 518, see figures 3, 11 and 13.

[0133] A position spring element 514 surrounds the spring section 525. In the illustrated embodiment, the position spring element 514 is a plurality of disc springs positioned coaxial with the shaft 520. A release spring element 513 surrounds the spring section 525 outside of the position spring element 514.

[0134] A threaded first spring housing 519 houses the position spring element 514, the release spring element 513 and the second spring housing 518 as best seen in figures 11 and 13. The first spring housing 519 is fastened to the shaft 520 in the threaded section 527. A lock nut 5190 secures the first spring housing to the shaft 520.

[0135] The position spring element 514 is biased between an internal face 5191 of the first spring housing 519 and the spring shoulder 524 and / or the cone end face 5129 (see figures 11 and 13). The position spring element 514 abuts the cone end face 5129. The release spring element 513 is biased between the internal face 5191 of the first spring housing 519 and the rim 5181. When the lever 550 is in the passive position 5502 and the shaft 520 is in the first position 5202, the cone 512 abuts the cone shoulder 522. The spring shoulder 524 is flush with the cone end face 5129. Thus, the position spring element 514 abuts both the spring shoulder 524 and the cone end face 5129 as seen in figures 3 and 11. The pipe stopper disc 530 is fastened to a piston housing 13 and the rim flange 534 rests in a corresponding step in the piston housing 13 as seen in figures 3 and 4. The pipe stopper disc 530 is static relative to the piston housing 13 and the shaft 520 is axially moveable within the piston housing 13. When the shaft 520 is in the first position 5202, each segment 510 abuts the segment face 533 at a segment sliding end face 5108 which is opposite to the segment end face 5109. The release spring element 513 acts in one end on the pipe stopper disc 530 through the segments 510 and the rim 5181 and in the opposite end on the first spring housing 519. Thereby the release spring element 513 creates an axial force in the second direction D2 and forces the shaft 520 in the D2 direction. Thereby the segments 510 move inwards towards the centre axis XI as seen in figures 3 and 11.

[0136] A pipe 99 is pushed into an entrance 130 in the piston housing 13 until the pipe 99 abuts the pipe stopper disc 530.

[0137] When the shaft 520 is displaced in the first direction DI to the second position 5204 (as seen in figure 8), the position spring element 514 bias the cone 512 against the cone shoulder 522 such that the cone 512 follows the movement of the shaft 520. The segments 510 are pressed radially outwards as the wedge-shaped inner surface 517 slides against the tapered wedge face 5121 until the holding face 516 abuts an internal wall 996 of the pipe 99 as seen in figure 8.

[0138] The distance displaced by the shaft 520 between the first position 5202 and the second position 5204 is fixed. The radial displacement of the segments 510 is also fixed as long as the cone 512 does not slide along the shaft 520. The cone 512 and the segments 510 are dimensioned to fit a known tube 99 with a known internal diameter. If the internal diameter is uneven, or the wall thickness of the tube 99 is larger than expected such that the internal diameter is less than expected, the segments 510 abut the internal wall 996 before the lever 550 would reach the lever lock 560 if the cone 512 was fixed to the shaft 520. However, according to the present disclosure if the internal diameter is uneven, or the wall thickness of the tube 99 is larger than expected, the cone 512 slides along the cone section 523. The cone 512 does no longer abuts the cone shoulder 522, and the cone end face 5129 is no longer flush with the spring shoulder 524. The position spring element 514 abuts the cone end surface 5129 and bias the cone 512 towards the coupling head as seen in figure 13. Thereby the segments 510 are still pressed outwards towards the internal wall 996 with sufficient force to maintain the tube 99 stable even if the internal diameter is less than expected and the lever 550 reach the lever lock 560.

[0139] The segments 510 are kept in the locking-position by the lever lock 560 securing the lever 550 in the active position 5504.

[0140] When the shaft 520 is displaced in the second direction D2 to the first position 5202 (as seen in figure 3), the segments 510 retract radially inwards, supported by the release spring element 513 biasing the segments 510 in the first direction DI and thereby radially inwards towards the grooving apparatus centre axis XI when the cone 512 is moved in the second direction D2. As seen in figure 3, the fixture 50 is not engaged with the internal wall 996 of the pipe 99 when the shaft is in the first position 5202.

[0141] In a plane perpendicular to the centre axis XI, the coupling head 5201 has an unround shape. In figure 9a the coupling head 5201 is shown with an oval shaped circumference. The coupling head 5201 is positioned in a complementary shaped cavity 41 in the housing 40. The coupling head 5201 is displaceable in the axial direction within the cavity 41, as seen in figures 4 and 8. The coupling head 5201 and the shaft 520 cannot rotate around the centre axis XI as shown in figure 9a.

[0142] The shaft 520 has three functions. The shaft 520 works as an activator of the fixture 50. The shaft 520 transfers a torque from the pipe 99 to the housing 40 thereby avoiding rotation of the pipe 99 during grooving. The shaft 520 works as a sliding valve in a hydraulic system 6 as will be described in the following.

[0143] Now referring to figures 3 and 8. The receiving indentation 515 is positioned aligned with a grooving wheel 111. The grooving wheel 111 will be described in more details with reference to figure 4. A bump 995 is formed on the inside of the pipe 99 when the grooving wheel 111 is pressed against the outer surface of the pipe 99 to form the groove 994.

[0144] Now referring to figures 3 and 4. The hydraulic pump and drive mechanism 20 comprises the hydraulic system 6. The hydraulic system 6 comprises a volume compensated fluid reservoir 630. The volume compensated fluid reservoir 630 comprises a rigid house 6302. The rigid house 6302 comprises the housing 40, a flange part 19, and the pump housing 60. The volume compensated fluid reservoir 630 is sealed from an environment 6305 surrounding the grooving apparatus 1. The rigid house 6302 comprises a through hole 6303. An i nflata ble / deflata ble device 6301 is connected to the through hole 6303 such that the inflata ble / deflata ble device 6301 is positioned within the rigid house 6302 and in fluid connection with the environment 6305. The i nflata ble / deflata ble device 6301 is in the illustrated embodiment a flexible bladder. The through hole 6303 is positioned adjacent internal parts of the grooving tool 10. A tank line 6306 connects the volume compensated fluid reservoir 630 to the hydraulic pump housing 60. The tank line 6306 is an outlet from the volume compensated fluid reservoir 630 wherein the fluid 69 is stored.

[0145] A first gear pump 61 and a second gear pump 62 is positioned within the hydraulic pump housing 60 as shown in figures 4 and 6. The first gear pump 61 comprises one third spur wheel 203 and one fourth spur wheel 204. The third spur wheel 203 function as a first pump-gear, and the fourth spur wheel 204 function as a second pump-gear in the first gear pump 61. The second gear pump 62 comprises one third spur wheel 203 and one fourth spur wheel 204. The third spur wheel 203 function as the first pump-gear, and the fourth spur wheel 204 function as the second pump-gear in the second gear pump 62. The first gear pump 61 and the second gear pump 62 are connected in parallel. One side of the first gear pump 61 and one side of the second gear pump 62 are connected to the tank line 6306. The opposite side of the first gear pump 61 and the opposite side of the second gear pump 62 are connected to a pressure line 632 such that a hydraulic fluid flow and a hydraulic pressure can be provided within the pressure line 632. The pressure line 632 is connected to a flow restrictor 639 (as seen in figure 9b) and a pressure relief valve 68 (as seen in figure 9b). The pressure relief valve 68 is fluidly connected to the volume compensated fluid reservoir 630. The flow restrictor 639 may be adjustable which enables a displacement rate of the wheel-holders 110 to be adjusted. A too rapid displacementrate increases friction for the grooving wheels 111 to roll as desired. A too slow displacement rate results in the bump 995 not being formed due to the material not displacing as desired during the grooving operation.

[0146] The pressure line 632 is routed to connect the first gear pump 61 and the second gear pump 62 to a first hydraulic swivel coupling 640 (best seen in figure 4). The shaft 520 comprises a shaft return line 6308 and a shaft pressure line 6322. The shaft return line 6308 is fluidly communicating with the volume compensated fluid reservoir 630 through a return line 64 connected to the volume compensated fluid reservoir 630. The shaft return line 6308 is connectable to the first hydraulic swivel coupling 640 and a second hydraulic swivel coupling 650. The shaft pressure line 6322 is connectable to the first hydraulic swivel coupling 640 and the second hydraulic swivel coupling 650. A hydraulic line connected to a hydraulic swivel coupling is herein described as the hydraulic fluid is allowed to flow from the hydraulic line and through the hydraulic swivel coupling. A hydraulic line disconnected from a hydraulic swivel coupling is herein described as the hydraulic fluid is prevented from flowing from the hydraulic line and through the hydraulic swivel coupling.

[0147] The first hydraulic swivel coupling 640 is configured such that the shaft 520 may rotate around and displace along the apparatus centre axis XI. The second hydraulic swivel coupling 650 is configured such that the shaft 520 can rotate around and displace along the apparatus centre axis XI on an inner surface 6502 of the second hydraulic swivel coupling 650. The second hydraulic swivel coupling 650 is configured such that the base element 120 may rotate around the apparatus centre axis XI around an outer surface 6504 of the second hydraulic swivel coupling 650.

[0148] With the shaft 520 in the first position 5202, the first hydraulic swivel coupling 640 connects the pressure line 632 to the shaft return line 6308. The second hydraulic swivel coupling 650 connects the shaft return line 6308 to a grooving tool hydraulic line 634. The grooving tool hydraulic line 634 is routed to connect a piston chamber 14, wherein a ringshaped hydraulic piston 12 is positioned, to the second hydraulic swivel coupling 650. The shaft pressure line 6322 is disconnected from the first hydraulic swivel coupling 640 and the second hydraulic swivel coupling 650 when the shaft 520 is positioned in the first position 5202. Thereby, the shaft 520 in the first position 5202 connects the first gear pump 61, the second gear pump 62 and the piston chamber 14 to the volume compensated fluid reservoir 630 through the return line 64.

[0149] With the shaft 520 in the second position 5204, the first hydraulic swivel coupling 640 connects the pressure line 632 to the shaft pressure line 6322, and the second hydraulic swivel coupling 650 connects the shaft pressure line 6322 to the grooving tool hydraulic line 634. The shaft return line 6308 is disconnected from the first hydraulic swivel coupling 640 and the second hydraulic swivel coupling 650. The shaft return line 6308 is therefore only connected to the volume compensated fluid reservoir 630 in the second position 5204. Thereby, the shaft 520 in the second position 5204 connects the first gear pump 61 and the second gear pump 62 to the piston chamber 14.

[0150] Referring to figures 2 and 4. The grooving tool 10 is arranged to rotate relatively to the housing 40 and around the apparatus centre axis XI. As previously described, the internal spur gear 206 is rotationally stiff fastened to the base element 120 and the drive shaft 207 and the fifth spur wheel 205 is therefore configured to rotate the grooving tool 10 around the apparatus centre axis XI. Referring to figures 4, 7a and 8. The grooving tool 10 comprises a plurality of wheel-holders 110. Each wheel-holder 110 comprises the grooving wheel 111 on a wheel axle 113. The illustrated embodiment is shown with three wheel-holders 110. The grooving wheel 111 has a smaller diameter 1112 on each side of a ridge 112 and are arranged to limit the inward radial movement of the grooving wheel 111 during the grooving operation when the grooving wheel 111 forms a groove 994 in the pipe 99 (as seen in figure 8). An additional effect of the smaller diameters 1112 is that they prevent a pipe end portion 990 extending from the groove 994 to radially raise or buckle during the grooving operation.

[0151] Each wheel-holder 110 is connected to the base element 120 and are radially displaceable between an idle position 1102 (as seen in figures 3 and 4) and a grooving position 1104 (as seen in figure 8). The idle position 1102 is easily identified by the hydraulic piston 12 being biased towards a starting position 141 within the piston chamber 14. The hydraulic piston 12 being displaced from the starting position 141 to an intermediate position 145 within the piston chamber 14 displaces the wheel holder 110 to the grooving position 1104. Now referring to figures 5 and 7a-b. The wheel-holder 110 comprises two projections 1106 arranged to engage with corresponding slots 1202 in the base element 120. The corresponding slots 1202 are shown in figure 7b by the dashed lines. The corresponding slots 1202 can also be seen in figure 5. The projections 1106 and the corresponding slots 1202 are arranged radially towards the grooving apparatus centre axis XI.

[0152] The wheel-holders 110 are connected to the hydraulic piston 12. The wheel-holders 110 are radially displaced by an axial displacement of the hydraulic piston 12. In the illustrated embodiment, the wheel-holder 110 comprises four protrusions 114, two protrusions 114 on each side of the wheel-holder 110 (see figures 2 and 7a). The protrusions 114 are arranged to engage with corresponding recesses 121 in the hydraulic piston 12. The recesses 121 create an angle with the apparatus centre axis XI (best seen in figures 3 and 7c). The projections 1106, corresponding slots 1202, the protrusions 114 and the recesses 121 are therefore arranged such that the wheel-holders 110 displace radially towards the apparatus centre axis XI when the hydraulic piston 12 is displaced in the first direction DI. The radial displacement depends on the angle with the apparatus centre axis XI of the protrusions 114 and recesses 121. As a non-limiting example, a displacement of the hydraulic piston of 10 mm in the first direction DI corresponds to a radial displacement of 2.5 mm of the wheel-holders 110. The hydraulic piston 12 is displaceable in the first direc- tion DI by filling the piston chamber 14 with the hydraulic fluid 69. The hydraulic piston 12 is biased with a plurality of springs 16 (best seen in figure 5) towards the second direction D2. The spring 16 is in the illustrated embodiment shown as a coil spring.

[0153] Figures 9a-b show a first plug 638 for filling the volume compensated fluid reservoir 630 with the hydraulic fluid 69.

[0154] The hydraulic system 6 may be filled with the hydraulic fluid 69. The filling process comprises the steps of:

[0155] - remove the first plug 638;

[0156] - fill the hydraulic fluid 69 into the volume compensated fluid reservoir 630 until the volume compensated fluid reservoir 630 is full; and

[0157] - fit the first plug 638 to seal the volume compensated fluid reservoir 630 from the environment 6305 surrounding the grooving apparatus 1.

[0158] The power unit 9, such as the handheld drill 90 is connected to the grooving apparatus 1 via the coupling 480 as shown in figure 1. The grooving apparatus 1 is connected to a pipe end portion 990 of a pipe 99. The pipe 99 is locked to the grooving apparatus 1 by moving the lever 550 from the passive position 5502 to the active position 5504. The lever 550 is secured by the lever lock 560 as seen in figure 2. The fixture 50 thereby fixes the pipe 99 as previously described.

[0159] The handheld drill 90 makes the grooving tool 10 rotate by activating the hydraulic pump and drive mechanism 20. The first gear pump 61 and the second gear pump 62 are operated in parallel and increase the hydraulic pressure to a hydraulic pressure which may for illustrative purposes be 10 bar. The pressure relief valve 68 may be set to for example 10 bar. The hydraulic pressure is delivered to the piston chamber 14 and acts on the hydraulic piston 12. The hydraulic pressure is delivered through the pressure line 632, the first hydraulic swivel coupling 640, the shaft pressure line 6322, the second hydraulic swivel coupling 650, and the grooving tool hydraulic line 634 and is then 10 bar. Due to the flow restrictor 639 and the plurality of springs 16, the hydraulic piston 12 is displaced slowly along and parallel the grooving apparatus centre axis XI within the piston chamber 14. Thereby the wheel-holders 110 are displaced slowly and radially inwards and the grooving wheels 111 slowly make the groove 994 in the outer surface of the pipe 99 when the grooving wheels 111 rotate around the pipe 99. The i nf lata ble / def lata ble device 6301 inflates with air from the environment 6305 surrounding the grooving apparatus 1 as the hydraulic fluid 69 is displaced from the volume compensated fluid reservoir 630 to the piston chamber 14. The i nflata b le / def lata ble device 6301 inflates by the same volume as used to displace the hydraulic piston 12.

[0160] By the end of the piston stroke and or when the smaller diameters 1112 is abut the pipe 99, i.e. the groove 994 is completed, the drill 90 may be stopped. When the lever 550 is displaced to the passive position 5502 (seen in figures 1, 3 and 5), the hydraulic fluid 69 in the piston chamber 14 is routed to the volume compensated fluid reservoir 630 and the springs 16 force the hydraulic piston 12 back to the starting position 141. Thereby the wheel-holders 110 and the grooving wheels 111 are returned to the idle position 1102. As the hydraulic fluid 69 returns from the piston chamber 14 into the volume compensated fluid reservoir 630 the i nflata b le / def lata ble device 6301 deflates to the state prior to displacing the hydraulic piston 12.

[0161] The smaller diameter 1112 of the grooving wheel 111 secure that the pipe end 991 is kept straight during the grooving operation and that the groove 994 is made to a predetermined depth. The predetermined depth is determined by the radial difference between the smaller diameter 1112 and the ridge 112.

[0162] The fourth spur wheel 204 of the first gear pump 61 rotates the connected drive shaft 207. The drive shaft 207 rotates the fifth spur wheel 205, and thereby the internal spur gear 206 rotates. The fourth spur wheel 204 of the second gear pump 62 is connected to the internal spur gear 206 in the same manner. The base element 120 is fixed to the internal spur gear 206 as seen in figure 2. Thereby, when the lever 550 is in the active position 5504 and the power unit 9 is activated, this activates the hydraulic pump and drive mechanism 20. As a result, the grooving wheels 111 are displaced slowly and radially inwards into the pipe 99 and at the same time the grooving wheels 111 are rolling around the full circumference of the pipe 99. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0163] The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

C l a i m s1. A grooving apparatus (1) arranged for rolling a circumferential external groove (994) in a pipe end portion (990), the grooving apparatus (1) forms a centre axis (XI), the grooving apparatus (1) comprises a fixture (50) and a grooving tool (10), the fixture (50) is configurable between a release-position and a fixing-position, in the fixing-position the fixture (50) is configured to engage an internal wall (996) of a pipe (99) and fix the grooving apparatus (1) to the pipe end portion (990) such that a pipe centre axis (X99) is coaxial with the centre axis (XI), the grooving tool (10) is rotatable around the centre axis (XI), c h a r a c t e r i z e d i n that:- the grooving tool (10) comprises a hydraulic piston (12) and at least one wheelholder (110);- the hydraulic piston (12) is displaceable in a direction along the centre axis (XI);- the hydraulic piston (12) is configured to displace the wheel-holder (110) in a radial direction relative to the centre axis (XI) between an idle position (1102) and a grooving position (1104); and- the wheel-holder (110) comprises a grooving wheel (111).

2. The grooving apparatus (1) according to claim 1, wherein the grooving apparatus (1) comprises at least three wheel-holders (110).

3. The grooving apparatus (1) according to any one of claims 1 and 2, wherein the grooving tool (10) comprises a base element (120) and the wheel-holder (110) is radially displaceable connected to the base element (120).

4. The grooving apparatus (1) according to any one of the preceding claims, wherein the grooving apparatus (1) is configured to receive a rotational force from a drive shaft (207), the drive shaft (207) is off-set from the centre axis (XI).

5. The grooving apparatus (1) according to any one of the preceding claims, wherein the grooving apparatus (1) is configured to receive a hydraulic fluid (69) from a pressure line (632).

6. The grooving apparatus (1) according to claim 4, wherein the grooving tool (10) comprises an internal spur gear (206).

7. The grooving apparatus (1) according to any one of the preceding claims, wherein the hydraulic piston (12) is biased towards a start position (141).

8. The grooving apparatus (1) according to any one of the preceding claims, wherein the fixture (50) is configurable by displacing a shaft (520) parallel to the centre axis (XI).

9. The grooving apparatus (1) according to any one of the preceding claims, wherein the rotational force and the hydraulic fluid flow is provided by a battery powered power unit (90).

10. A grooving system arranged for rolling a circumferential external groove (994) in a pipe end portion (990), c h a r a c t e r i z e d i n that:- the grooving system comprises a grooving apparatus (1) according to any one of claims 1 to 9;- the grooving system comprises a hydraulic pump and drive mechanism (20), a fluid reservoir (630), and a fixture (50);- the hydraulic pump and drive mechanism (20) is configured to connect to a power unit (9) and receive a rotational force from the power unit (9) via an input shaft (200);- the hydraulic pump and drive mechanism (20) is configured to create an output, the output comprises a hydraulic fluid flow and a rotational force, the output is transferred to the grooving apparatus (1);- the fixture (50) forms a fixture centre axis coaxial with a grooving tool centre axis (XI); and- the fixture (50) is configured for engaging an internal wall (996) of a pipe (99) and fix a pipe end portion (990) to the grooving apparatus (1).

11. The grooving system according to claim 10, wherein the grooving system is configured to be handheld.

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