The present invention relates to a hand held pipe coupling apparatus, and in particular an apparatus for the in-situ compression of a compressible pipe fitting.

Compression fittings are commonly used in the instrumentation tube fittings industry as well as in shipbuilding, aerospace, automotive, and construction to connect two pipes together and provide a seal against leakage, particularly for high pressure applications. Compression fittings generally comprise a pipe fitting, a compression fitting and an inner member that is typically a compression ring or ferrule. The compression fitting is used to apply a compressive force to the ferrule to clamp the inner member, or ferrule, around the pipe and to compress it against the pipe fitting. As the ferrule is compressed between the compression fitting and the pipe fitting the ferrule seals the space between the pipe, the compression fitting and the pipe fitting, thereby forming a sealed joint.

UK patent number GB2423561 describes a pipe coupling comprises an pipe fitting body including having and end portion, or ferrule, with an interior bore having a plurality of annular protuberances defining teeth extending into the bore, and a collar. The collar is provided around the inner body and the inner body and the collar each have

corresponding tapered conical surfaces inclined to their axes. A pipe is located within the bore of the inner member, and the collar and the pipe fitting are longitudinally forced together. As the pipe fitting body and collar are forced together the collar is urged over the inner member. The inclined surfaces cooperate such that as the collar is linearly forced against the inner member it applies a circumferential compressive force to the inner member that acts to deform the inner member radially inwards. As the inner member is deformed teeth engage the pipe and bite into its surface creating a seal with pipe. The collar is retained in engagement with the pipe fitting body to an in engagement with the ferrule to maintain the seal. To secure a compression fitting of the type described in GB2423561 a large linear force is required to urge the pipe fitting body and the collar together and force the collar over the ferrule portion to cause deformation. I n certain compression fittings the liner force may be achieved using a screw thread converting a large rotational advantage into a linear force. A screw thread requires the collar to be rotated during fitting which causes a corresponding twisting of the inner member which is undesirable as this rotation effects the manner in which the inner member bites into the pipe and therefore results in a less than optimum seal. It is therefore preferable that a direct linear force is applied to cause solely linear movement of the collar and inner body.

It is known to use clamping jaws operated by a hydraulic ram to force such fittings together. Known clamping tools include a hand held tool including a pair of clamping jaws and a ram, which is connected via hydraulic lines to a separate pump, which is typically a hand pump, to provide the required fluid pressure to operate the jaws. Pipe connection therefore requires a first operator to hold the hand held clamping jaws in position, and at least one further operator to work the pump. In addition, the requirement to connect the tool to a hydraulic pressure source limits the reach of the tool, with the hydraulic pipes also making manipulation and reorientation of the tool difficult. The additional hydraulic pressure source is also an additional and undesirable cost.

It is therefore desirable to provide an improved ha nd held pipe coupling apparatus which addresses the above described problems and/or which offers improvements generally.

According to the present invention there is provided a hand held pipe coupling apparatus as described in the accompanying claims. In an embodiment of the invention there is provided a hand held pipe coupling apparatus for in-situ fitting of compressible pipe connectors; the apparatus comprising a body including grip means to enable the apparatus to be held by an operator; clamping jaws incorporated on the apparatus configured to receive and clamp a compressible pipe connector; an actuator incorporated on the apparatus and operatively connected to the clamping jaws to cause movement thereof; and drive means incorporated on the apparatus and arranged to provide drive to the actuator. Providing an actuator and drive means on the apparatus enables the apparatus to be self-contained and to be operated without the requirement for external ancillary equipment such as a fluid compressor or hand pump to provide drive means to the clamping jaws. As such an operator is able to use the apparatus independently without requiring additional persons to operate a pump or the like, and the absence of connecting hydraulic pipes enables a far greater freedom of movement of the apparatus.

The clamping jaws may comprise a pair of jaw members linearly movable relative to each other between an open configuration and a clamped configuration, and the actuator may comprise an actuating piston connected to one of the clam ping jaw members arranged to move said clamping jaw relative to the other clamping jaw to move the clamping jaws from the open to the clamped configuration.

The drive means preferably comprises a pump fluidly connected to the actuating piston and an electric motor operatively connected to the pump. The combination of a pump and electric motor enable a driving force for the clamping jaws to be generated on-board the apparatus with the motor driving the pump to generate pressurised fluid pressure to actuate the jaws, thereby obviating the requirement for external equipment. The pump preferably comprises a low pressure chamber and a high pressure chamber having a smaller cross sectional area than the low pressure chamber, and a piston configured to simultaneously compress the fluid within both chambers, and both the low pressure and high pressure chambers include and outlet in fluid connection with the actuating chamber. A relatively small cross sectional high pressure chamber is required to generate the required fluid pressures to compress the pipe connector. However, the volume of fluid supplied by the high pressure chamber is relatively low given its small cross section. The use of a single chamber having such a low stroke volume would result in the jaws taking a relatively long time to close, would result in the operator having to hold the apparatus in position for an undesirable amount of time. The use of a higher volume, lower pressure chamber enables the jaws to be rapidly closed across the first range of travel where the required pressure is low, as well as providing the required high fluid pressure when compression of the connector is required.

The clamping jaws are preferably configured to operate across a first closing range of movement in which the jaws move from the open configuration into engagement with a connector located therebetween, and a second range of movement in which the jaws operate in engagement with the connector to apply a compressive force thereto, wherein the low pressure chamber is connected to a pressure release valve configured to divert fluid from the low pressure chamber away from the actuating cylinder during the second range of movement when the pressure within the chamber exceeds a maximum predetermined level, following which the pump continues to supply pressurised fluid to the actuating cylinder from the high pressure chamber only. As such, the low pressure chamber is able to actuate the jaws to close more rapidly across the first range of operation to increase speed of operation of the apparatus, with the high pressure chamber then being used to deliver the required force to compress the connector.

The body of the apparatus may comprise a housing casing and an electric motor is arranged within the housing adjacent the clamping jaws such that the rotational axis of the motor is substantially parallel to the longitudinal axis of the clamping jaws along which the jaw members move relative to each other. This arrangement optimises the space within the housing and enables the size of the apparatus to be minimised.

The hand held pipe coupling apparatus preferably further comprising a cam operatively connected to the electric motor and arranged such that rotation of the cam actuates liner motion of the pump. The pump comprises a piston rod connected to the piston at one end and having an opposing end in engagement with the cam, with the pump being arranged transverse to the axis of the motor and cam.

A fluid reservoir may be incorporated on the apparatus in fluid connection with both the low pressure and high pressure chambers of the pump to supply fluid thereto. Thereby avoiding the need for a separate external fluid source ensuring complete independence of the apparatus.

Biasing means may be arranged to return the clamping jaws to the open position when pressure from actuating piston is released.

In another aspect of the invention there is provided a hand held pipe coupling apparatus for in-situ fitting of compressible pipe connectors; the apparatus comprising first and second clamping jaw members linearly movable relative to each other between an open configuration for receiving a pipe connector and a clamped configuration for compressing said connector. The first clamping jaw includes a body section and a jaw section extending from the body section. A linear, cylindrical bore is formed in the body section of the first clamping jaw. A piston member is slidingly received in the bore, with a piston chamber being defined between an inner piston face of the piston and a closed end of the bore. A fluid inlet arranged to supply pressurised fluid into the piston chamber. The piston is arranged to operatively engage the second clamping jaw to move the second clamping jaw towards the first clamping jaw to cause compression of the pipe connector.

Specifically, the piston includes an engagement surface at the opposing end to the inner piston face that engages a corresponding engagement surface of the second clamping jaw. Providing an arrangement in which a piston cylinder is formed in the body section of the first clamping jaw obviates the requirement for a separate hydraulic cylinder including its own casing, piston rod and connections. In this way, significant weight, size and cost savings may be made enabling the tool to be easily held by a single operative. The second clamping jaw preferably comprises an engagement section arranged to be engaged by the piston that extends in a direction perpendicular to the direction of travel. The apparatus further including an alignment shaft arranged parallel to the direction of travel of the second jaw section and extending through a corresponding aperture in the engagement section such that the engagement section is able to slidingly travel along the alignment shaft, and wherein the end of the piston includes a bore configured to receive the alignment shaft to enable the alignment shaft to slide within the piston as the piston actuates the second clamping jaw.

The hand held pipe coupling apparatus may further comprise a biasing member operatively engaged with the engagement section on the opposing side of the engagement section to the piston biasing the second clamping jaw to the open position.

The biasing member may be a compression spring provided about the alignment shaft arranged to be compressed as the piston moves the second clamping jaw to the closed position.

The jaw section and body section of the first clamping member may be an integrally formed unitary component.

The bore of the first clamping jaw may extend parallel to the direction of travel of the second clamping jaw.

The present invention will now be described by way of example only with reference to the following illustrative figures in which:

Figure 1 shows a known pipe connector;

Figure 2 shows a pipe connector apparatus according to an

embodiment of the present invention;

Figure 3 shows the pipe connector of Figure 2 with a casing

section removed to display the internal configuration;

Figure 4 is a section view of a dual pressure pump and cam

arrangement according to an embodiment of the invention; Figure 5 is a section view of the pipe connector; and

Figure 6 shows a pipe connector according to another

embodiment of the invention.

Referring to Figure 1 a coupling 1 of the prior art comprises a body 2 and a pair of collars 4. The body 2 has an integral frusto-conical end sections 6 at opposing ends which taper to the distal ends. The conical end sections 6 each have an inner bore 8 having a number of circumferentially extending interior annular protuberances or teeth 10.

Each collar 4 includes an inner bore 12 and part of the collar 4 is configured fit around the body 2 in an interference fit to hold the collar 4 on the body 2. The bore 14 of each collar 4 includes an internal frusto-conical profile 14 that corresponds to the outer frusto conical profile of the end section 6.

In use two pipes 16 to be connected are inserted through the bores 12 of the collars 4. The pipes 16 are then inserted through the bores 8 of the respective end sections 6 until they have at least passed the last tooth 10 and preferably until they abuts the abutment faces 17 at ends of the bores 8 defining which define a stop.

Once the pipes 16 are located, the collars 4 is forced in opposing direction towards each other onto the respective end sections 6. To achieve this opposing linear forces are required to force the collars 4 towards each other and compress them onto the body section 2.

The collars 4 each include an annular end face 18 oriented substantially perpendicular to the longitudinal axis which define abutment surfaces to which the linear forces may be applied.

As the collars 4 are forced over the external frusto-conical surfaces of the end sections 6, the external frusto-conical surfaces 6 engage with the internal frusto-conical surfaces 12 of the collars 4 causing compression of the end sections 6. Internally during compression, tube grip occurs as the teeth 10 make contact with the pipes 16. The teeth 10 cut into the outer skin of the pipes 16 until a point where the force required to cut into the skin becomes larger than the force required to deform the pipes 16. At this point the pipes 16 will begin to deform resulting in the pipes 16 swelling in some areas and in some areas contracting. This deformation combined with the initial tube bite produces a high quality seal the pipes 16 and the teeth 10 of the end sections 16, as well as resulting in a form that cannot be removed from the end sections 6.

An apparatus for compressing the pipe coupling 1 is now described in accordance with an embodiment of the invention. In Figure 2 a hand held pipe coupling apparatus 20 is shown comprising including a body 22 comprising a housing casing 24, a first handle defined by an aperture 26 formed in the housing casing 24 including a handle grip portion 28, and a second handle 30 connected to an extending outwardly from the housing casing 24. A power switch or trigger 27 is located within the first handle 26 such that it may be operated by the same hand that grips the handle 26. The body 22 is a suitable size and weight that the handheld pipe coupling apparatus 20 may be held and supported by a single user gripping one or both of the first handle 28 and second handle 30. The body 22 comprises a hollow housing configured to house and support the components of the apparatus 1.

A set of clamping jaws 32 is mounted to the body 22. The jaws 32 include a first outer clamping jaw 34 and a second inner clamping jaw 36. The outer clamping jaw 34 and inner clamping jaw 36 include a first clamping head 38 and second clamping head 40 extending from a first clamping jaw body 35 and second clamping jaw body 37

respectively. The first 38 and second 40 clamping heads extend in a substantially perpendicular direction away from the clamping bodies 35 and 37 and extend outwardly from the body 22 in s substantially perpendicular direction relative to the longitudinal axis of the clamping jaws 32. The clamping heads 38 and 40 include at their outer most face a channel 42 formed within the clamping heads 38 and 40. The channels 42 extending longitudinally through the clamping heads 38 and 40 and are open at the outer most face of the clamping heads 38 and 30 such that the clamping head is substantially "U" shaped. Each channel 42 has a substantially semi-circular profile at its base and is configured to receive a cylindrical pipe through the opening of the channel 42, with the pipes able to pass longitudinally through both clamping heads 38 and 40. Each clamping head 38 and 40 includes a profile 41 on its inner surface coincident with the channel 42 corresponding to the end profile of the pipe collars 4 of the pipe coupling 1 which has a greater diameter than the width of the channel 42 but which does not extend entirely through the clamping head 38/40 but rather defines a seat for receiving the respective collar 4.

The outer clamping jaw 34 includes a longitudinally extending guide channel 48 formed in the clamping jaw body 35. The outer clamping jaw 34 is preferably secured to the body 2 and fixed in position relative to the body 2 by screws or other semi-permanent fixing. The body 37 of the inner clamping jaw 36 is slidingly received within the guide channel 48 of the outer clamping jaw 34. The inner clamping jaw 36 includes a pair of transversely opposed guide channels 54 that receive corresponding guide rails projecting from the inner walls of the channel 48 of the outer clamping jaw 34, although it will be appreciated that this arrangement could be reversed. The inner clamping jaw 36 slides relative to the outer clamping jaw 34 along the guide rails of the outer clamping jaw 34.

As shown in Figure 3, an electric motor 56 is incorporated within the housing 24. The electric motor 56 is located beneath the clamping jaws 32, and preferably immediately adjacent the jaws 32 and oriented such that the axis of rotation 58 of the motor 56 extends parallel to the longitudinal access of the clamping jaws 32. The electrical motor 56 is connected to a cam 60 via an epicyclic gear box 62. From the section view in Figure 4 it can be seen that the cam 60 is rotationally mounted to the epicyclic gear box 62. Preferably the cam 60 and motor 56 share a common rotational axis with the absence of any offset optimising the space within the casing 24 and enabling a compact

arrangement. A reciprocating pump 64 is arranged directly above the cam 60. Here the terms "above" and "below" are used relatively with reference to an orientation in which the clamping jaws 32 are arranged at the top of the apparatus with the motor arranged beneath the clamping jaws 32. It will be appreciated that these do not limit the actual positioning of these elements in use and instead refer only to their relative positioning within the apparatus 1. The reciprocating pump 64 comprises a piston rod 66 connected to a piston 68. The distal base end of the connecting rod 64 is arranged such that it is engaged in constant contact with the rotating surface of the cam 60. As shown in Figure 4, the pump 64 comprises a dual chamber arrangement including a high pressure chamber 70 and a low pressure chamber 72 formed in the manifold 74. The low pressure chamber 72 is located beneath the high pressure chamber 70 and has a diameter that is greater than the high pressure chamber 70. The low pressure chamber 72 extends into the manifold from the cam chamber 73. The diameter of the low pressure chamber 72 is then stepped inwardly to the high pressure chamber 72. The piston 64 includes a first low pressure piston section 74 that comprises a base 76 and side wall 78 with an open upper end such that the low pressure piston section 74 is a substantially cup-shaped open topped cylinder. The low pressure piston 74 is configured to slide within the low pressure chamber 72. A high pressure piston section 80 comprises a shaft that is co-axial with the low pressure piston section 74 and extends from the base thereof. The outer surface of the high pressure piston section 80 is spaced radially inwards from the wall 78 of the low pressure piston section 74 defining a void 82 therebetween. The upper end of the high pressure piston section extends into the high pressure chamber 70 and is configured to slide therein.

A first seal 86 is provided in the outer wall of the low pressure chamber 72 and seals between the low pressure chamber 72 and the low pressure piston section 74. A second seal 86 is provided in the outer wall of the high pressure chamber 70 and seals between the high pressure chamber 70 and the high pressure piston section 80. The second seal 86 fluidly isolates the low pressure chamber 72 from the high pressure chamber 70. A low pressure outlet 88 extends from the upper end of the low pressure chamber 72 for transporting low pressure fluid to the actuating cylinder described below. A high pressure outlet 90 extends from the upper end of the high pressure chamber 70 for transporting high pressure fluid to the actuating cylinder. The low pressure outlet 88 and the high pressure outlet 90 are connected to the inlet of hydraulic ram 90 which defines the actuating cylinder. As shown in Figure 5, the hydraulic ram 90 includes a cylinder 92 and piston 94. A piston chamber 96 is defined between the inner face 98 of the piston 94 and the cylinder 92. At a position longitudinally spaced from the inner face 98 towards the distil end face 100 of piston 94 the diameter of the piston 94 is reduced and extends through a corresponding aperture 102 formed in a downwardly extending connection of the inner jaw 36. The step in the piston 94 created by this reduction in diameter creates a first abutment face 104 which is arranged to engage with a corresponding abutment face 106 on the inner surface of the connection portion 102 of the inner jaw 36. The diameter of the aperture 102 is substantially equal to the diameter of the reduced diameter section 108 which slides within the aperture

102. At the distal end of the piston 90 the diameter is stepped outwardly again creating a wider distil end portion 110. This stepped change in diameter creates a second abutment face 102 that is configured to abut against a second abutment face on the outer face of the connecting portion 102 of the inner jaw 36.

In use, prior to operation the jaws 32 are in the open fully separated open condition. The apparatus 20 is located over a pipe connection such that the first pipe 16 is received with the channel of the outer jaw 34 and the second pipe 16 is located within the channel of the inner jaw 36.

A coupling 1 is located between the two pipes with the end of each pipe 16 being inserted into the opposing end sections 6 of the body 2 and through the corresponding collars 4. Prior to operation the hydraulic fluid pressure in the chamber 96 of the actuating piston 90 is substantially zero. Of the pipes to be joined and the corresponding coupling located correctly within the jaws 32 the tool is then operated to secure the coupling 1 to the pipes. The power switch 27 is operated to cause the jaws 32 to close. The power switch 27 activates the motor 56 which in turn drives the cam 60 to operate the pump 66. Given the greater swept volume of the low pressure chamber 72 of the pump 66, the initial movement of the jaws 32 is actuated predominantly by the lower pressure chamber 72. At this initial stage the jaws 32 are not actively engaged with the coupling 1. The low pressure piston enables the gap between the jaws 32 and the coupling 1 to be quickly closed for fast operation.

Fluid from the pump 66, including fluid from the low pressure 72 and high pressure 70 chambers are pumped into the piston chamber 96. As the pressure in the piston chambers 96 rises the pressure against the end face 98 of the piston 90 causes the piston to move longitudinally within the chamber 92 in the direction of the distal end 100 as the chamber 96 fills. The piston 90 is moved into engagement with the abutment face 104 of the piston engaging the corresponding abutment face 106 of the inner jaw 36. As the piston 90 continues to move it pushes against the connecting section 102 of the jaw 36 causing the inner jaw 36 to slide towards the outer jaw 34 thereby closing the jaws 32. The piston 90 operates across this initial distance of travel mainly under the action of the low pressure chamber 72.

Eventually the jaws 36 come into contact with the collars 4 of the coupling 1. As the jaws 32 continue to close the collars 4 are forced over the frusto-conical end sections 6 causing deformation and radial compression with the teeth 10 biting into the pipes 16. At this stage the jaws 32 are no longer substantially freely movable and the force required to continue to close the jaws 32 substantially increases thereby requiring a significantly elevated piston pressure. As the pressure in the piston chamber 96 increases further the pressure release valve of the low pressure piston is released such that the pump 66 continues to operate on the basis of the high pressure piston alone, with fluid from the low pressure piston being directed back to the hydraulic fluid reservoir (not shown). Pressurisation of the actuating cylinder 90 continues to increase to continue closing of the jaws 32 until the coupling 1 is fully closed and the jaws 32 can no longer move. When this over pressure threshold is reached, which will typically be approximately 100 psi, excess pressure from the high pressure chamber 70 is relieved via the high pressure piston over pressure release valve which comprises of spring loaded valve housed in a removable cartridge. The pressure release fluid is then fed back to the hydraulic oil reservoir.

When the operator recognises that the coupling 1 has been fully fitted the operation trigger switch is released deactivating the electric motor and shutting down operation of the pump 60. A pressure release trigger 29 is provided which releases pressure from the actuating piston chamber 96. A compression spring is provided between the inner jaw 36 and outer jaw 34 which, on release of the pressure within the actuating piston chamber 96 causes the jaws 32 to return to the open position. With the jaws 32 in the open position the tool may be removed from the pipe with the pipe in the fully coupled condition.

In another embodiment of the invention shown in Figure 6, the fixed clamping jaw 234 includes a body section 238 and a clamping section 236 that are integrally formed as a unitary part. The movable clamping jaw 236 is slidingly mounted to the fixed clamping jaw 234 in the same manner as the arrangement described above. The engagement section 300 of the movable jaw 236 projects downwardly perpendicular to the direction of travel of the jaw 236 and includes an aperture 302. A bore 292 is formed in the body section 238 of the fixed clamping jaw 234 defining a piston cylinder. A piston 290 is located within the cylinder 292 having an inner piston face 298 having a diameter equal to the diameter of the cylinder 292. A piston pressure chamber 296 is defined between the inner piston face 298 and the closed end of the piston chamber 296. The body 293 of the piston 290 includes a central bore 305 at the distal, non-process end within which is received an alignment shaft 310 for guiding travel of the piston and aligning the piston with the engagement section 300 of the sliding jaw 236. The alignment shaft 310 extends through the aperture 302 of the engagement section and is received at one end in the bore 305. A compression spring 312 is provided around the alignment shaft 310 of the opposing side of the engagement section. An inlet port 240 is formed in the body 238 that connects the piston chamber 296 with a pressurised fluid source that may be an on-board pump arrangement as described above or an off-board pump connected to the inlet port 240 via a high pressure line. To actuate the clamping jaws a high pressure fluid flows into the piston chamber 296 via the inlet port 240 pressuring the chamber 296 and applying a force to the inner piston face 298. As the pressure rises the piston is caused to move within the piston cylinder 292 in the direction of the fixed jaw 234. The distal end of the piston 290 defines an abutment surface 304 that engages a corresponding abutment surface 306 of the engagement section 300 causing the sliding jaw 236 to move towards the fixed jaw 236 along the alignment shaft 310. As the sliding jaw 236 continues to travel the alignment shaft is further received within the bore 305, and the engagement section 300 compresses the compression spring 312 which applies a returning forces against the action of the piston 290. Following compression of the fitting 1 the pressurised fluid is allowed to flow from the piston chamber 296 at which time the returning force of the spring 312 moves the engagement section 300 in the reverse direction causing the jaws to return to the open configuration.

In the prior art arrangement the clamping jaws are actuated by a separate hydraulic ram mounted within the casing of the tool, which requires significant space within the casing and significantly increases the weight of the tool. By forming a piston cylinder within the body of the fixed clamping jaw, and providing a position therein, the size, weight and cost of the tool is able to be significantly decreased.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.