Patent Description:
Hydraulic work tools are employed in numerous applications to provide a user with a desired mechanical advantage. One example is in crimping tools used for making crimping connections, such as crimping terminals onto conductors. Another example is in cutting tools where the tool enables the user to apply a relatively large amount of force or pressure.

There are known portable hydraulic tools that allow compressive forces of approximately <NUM> to <NUM> kilonewtons to be achieved. These tools are commonly used for operations to crimp or cut electric cables. These tools generally comprise a body in which are accommodated a fluid reservoir, a hydraulic pump, a cylinder and a piston capable of being moved inside the cylinder under the effect of an injection of pressurised fluid into the interior of the cylinder. These tools also comprise a tool head fixed to the body and adapted to receive for example a die set, one of the dies being operated by the piston. In several tools of this type, the dies are removable, and the head can receive different die sets depending on the operation to be performed.

However, in order to perform different operations like crimping and cutting with one tool, a detachable or exchangeable head is desired. Using the same work tool with different detachable/interchangeable heads, it is possible to change over to different applications where necessary.

A particular problem affecting tools with exchangeable heads is the longitudinal forces being transmitted, in other words, the compressive forces produced by the tools, because the coupling mechanism by which the exchangeable head is attached to the device naturally has to withstand these forces and the corresponding safety requirements are relatively high. The aim, therefore, is to find a coupling mechanism that can be handled quickly and easily and yet offers operational safety, even with high and very high longitudinal forces.

Quick-connect coupling mechanisms for such hydraulic tools are of course known per se.

<CIT> discloses a hydraulic apparatus with an interchangeable apparatus head and a hand-held pressing apparatus. The apparatus head can be associated with the hand-held pressing apparatus with a screw connection. The apparatus head is pushed over a hydraulic cylinder provided within the hand-held pressing apparatus and screw-connected to it by means of an external thread on the apparatus and a mating internal thread on the apparatus head. Such screw connections do not last.

<CIT> and <CIT> disclose a quick-connect coupling for connecting an exchangeable head to a pressing device with several balls radially movably disposed in a ball-holding part on the pressing device. The balls are radially movable between a locking position, in which the head is secured to the device and a release position, in which the head can be removed from the device. <CIT> is directed to a hydraulic system comprising a quick-connect coupling similar to the one described above. The mounting of the balls is burdensome. Besides, such complex mechanism is difficult to service.

In <CIT>, which discloses a device according to the preamble of claim <NUM>, an apparatus comprises a first interlocking structure with a T-shaped slot, a head comprises a second interlocking structure arms forming a T-shaped cross section sized to slide into the T-shaped slot of the first interlocking structure. The coupling system is not quick and not reliable.

Finally, in <CIT>a removable head is secured to a tool body through a plurality of levers. Such complex mechanism is difficult to service and mount.

With regard to the prior art described above, a technical problem for the invention is seen in further developing a device having a quick coupling system for fastening an exchangeable head in an advantageous manner, particularly as regards making it simpler to change the head. Indeed, although satisfactory in certain respects, a need remains for a quick coupling system allowing changing heads on a device with greater ease and reliability. Furthermore, it would be desirable to ensure that upon attaching the head to the device, the attachment is robust, and the head is in proper position and engagement with the device.

It is an object of the present invention to provide a device having a quick coupling system for fastening an exchangeable head, an exchangeable head, a hydraulic tool and a method for mounting an exchangeable head on a device, which overcome these drawbacks.

Accordingly, the present invention provides a device having a quick coupling system for fastening an exchangeable head according to claim <NUM>. More particularly, the device comprises:.

and wherein the locking unit comprises a first and a second half ring, wherein the half rings are radially movable between the locking position and the released position.

By using a first and second half rings for locking an exchangeable head to the device, a robust and reliable connexion is realized. The attachment allows the transmission of high forces between the device and the head, but also a reliable coupling system, easy to use and to manufacture, with low maintenance needs.

In an embodiment, each of the half rings comprises a first and a second end portion, each end portion comprise a groove, wherein the actuation unit comprises two actuation parts, each of the actuation parts having a first and a second actuation segments, and wherein the second actuation segment partly extend within the grooves. The grooves can be easily manufactured, and the mechanical transmission requires little or no maintenance.

In an embodiment, the second actuation segment of the first actuation part partly extends in the groove of the first end portion of the first and second half rings, wherein the second actuation segment of the second actuation part partly extends in the groove of the second end portions of the first and second half rings. In other words, the second actuation segments extend between the half rings and are arranged opposite to each other, such that a symmetry is realized. Thus, the effort applied to the rings are symmetrical, which reduce any premature wear.

In an embodiment, each of the half rings has a curved shape with a front surface, a rear surface, two end portions and two lateral portions extending between and sensibly perpendicular to the front and rear surfaces, wherein the rear surface is sensibly flat, wherein the front surface comprises a first area extending sensibly parallel to the rear surface and a second area having a surface forming an angle with regard to the rear surface, a shoulder being arranged between the first and second areas, such that the thickness of the half ring between the rear surface and the first area is greater than the thickness between the rear surface and the second area. The shape of the half rings increases the locking forces applied on the exchangeable head.

According to the invention, the quick coupling system further comprises a sleeve slidingly arranged around the quick coupling system, the sleeve being movable along the tool axis, and the actuation unit is connected to the sleeve and adapted to be radially moved by the sleeve from a rest position to an active position, wherein in the rest position the half rings are in the locking position, and in the active position, the half rings are forced in the released position. The sleeve is easy to actuate by a user and the risks of misuse are reduced.

In an embodiment, the sleeve comprises an internal surface facing the tool body and an external surface opposite the internal surface, wherein the internal surface comprises a slope which cooperates with the actuation unit, such that during a translation of the sleeve, the portion of the actuation unit cooperating with the sleeve slides along the slope, resulting in the actuation unit moving radially toward the tool axis between the rest position and the active position. The slope allows to displace the actuation unit in a continuous way.

In an embodiment, the slope is a sloped groove and a second part of the actuation unit is provided with a guiding pin which is arranged inside the sloped groove. The guiding pin is retained in the groove. More particularly, a first part of the actuation unit is provided with a guiding pin. A second part of the actuation unit is provided with a guiding pin. The first guiding pin extends in a first sloped groove. The second guiding pin extends in a second sloped groove.

In an embodiment, the main piston is axially displaceable along a cylinder axis between a rest position and an actuation position under the effect of an injection of pressurised fluid into the interior of the cylinder, wherein the main piston comprises a first end forming a piston surface, and a second end, opposite the first end, wherein the second end comprises a recess, in which an elastic element and a mushroom piston are arranged. The mushroom piston forms a secure system such that the user is certain that the exchangeable head is correctly engaged within the device. Indeed, through the mushroom piston, when engaging the head, there is a need of a minimal engagement force to be applied to the head by the user in order to correctly secure the head to the device.

In an embodiment, the device further comprises a pressure relief valve connected to the cylinder. This is to allow the automatic and rapid return of the fluid contained in the cylinder to the reservoir at the end of operation.

The present disclosure is also directed to an exchangeable head comprising a functional part adapted to apply a force on an element, and an interface part for coupling with a device having a quick coupling system as described above. The interface part comprises circular groove adapted to receive the locking unit, a chamfer for facilitating the insertion of the head within the device, and a recess for partly receiving the main piston. The chamfer is adapted to push the half rings of the device into the released position. The circular groove is adapted to receive the half rings when said rings are in the locking position.

In an embodiment, the circular groove is formed by a bottom, a first and a second lateral wall, wherein the second lateral wall is inclined with regard to the first lateral wall. This is to improve the engagement with the half rings. More particularly, the shape of the groove is adapted to the shape of the half rings.

In an embodiment, the head further comprises a head piston actuated by the main piston. The head piston actuates the functional part and forward the forces applied by the main piston to the functional part.

The present disclosure is further directed to a hydraulic tool comprising a device as already described and a head, wherein the quick coupling system is removably connectable to the circular groove of the exchangeable head, such that in the locking position of the locking unit, the exchangeable head is secured to the device with the half rings extending inside the circular groove, and in the released position, the exchangeable head can be removed from the device.

Finally, the present disclosure relates to a method for mounting an exchangeable head to a device comprising the following steps:.

wherein the connection between the head and the device requires a pushing force of at least <NUM> daN (<NUM> Newtons), and in particular of at least <NUM> to <NUM> daN (<NUM> to <NUM> Newtons).

Other features and advantages will become more apparent from the description that follows, which is purely illustrative, and not limiting and should be read with reference to the accompanying drawings, in which:.

On the different figures, the same reference signs designate identical or similar elements.

<FIG> shows a hydraulic tool <NUM> comprising a device <NUM> and an exchangeable head <NUM>. The device <NUM> comprises a quick coupling system <NUM> for fastening the exchangeable head <NUM> and a tool body <NUM> with a cylinder <NUM>. A main piston <NUM> is capable of being moved inside the cylinder <NUM> under the effect of an injection of pressurised fluid into the interior of the cylinder <NUM>. The tool body <NUM> extends longitudinally along a tool axis X.

The device <NUM> is commonly provided with a fluid reservoir <NUM> having a cavity <NUM> intended to contain fluid. The fluid is typically oil. The hydraulic tool <NUM> is notably a handheld hydraulic apparatus. An electric motor is for instance disposed in the device <NUM> or connected to the device <NUM>. Drive of the tool <NUM> is actuated by means of a battery integrated into the device <NUM>. When a finger operated switch <NUM> is actuated, fluid is pumped out of the reservoir <NUM> into the cylinder <NUM>, thereby moving the main piston <NUM>.

The quick coupling system <NUM> is arranged at a free end of the tool body <NUM>, as depicted in <FIG>. The quick coupling system <NUM> comprises an actuation unit <NUM> and a locking unit <NUM>.

The locking unit <NUM> comprises two half rings 34a, 34b. The first half ring 34a is identical to the second half ring 34b. First and second half rings 34a, 34b are arranged facing each other such that they define an opening.

As shown in <FIG>, each of the half rings 34a, 34b has a curved shape. Each of the half rings 34a, 34b comprises a front surface <NUM>, a rear surface <NUM>, two end portions 40a, 40b and two lateral portions 42a, 42b. The two lateral portions 42a, 42b extend between the front and rear surfaces <NUM>, <NUM>. The two end portions 40a, 40b extend between the front and rear surfaces <NUM>, <NUM>.

The rear surface <NUM> is sensibly flat. In other words, the rear surface <NUM> extends sensibly within a plan. The front surface <NUM>, opposite the rear surface <NUM> comprises two area <NUM>, <NUM>. The first area <NUM> is sensibly flat and extends parallel to the rear surface <NUM>. The second area <NUM> is inclined with regard to the first area <NUM>. A shoulder <NUM> is provided between the first and the second area <NUM>, <NUM>, such that the thickness between the rear surface <NUM> and the first area <NUM> is greater than the thickness between the rear surface <NUM> and the second area <NUM>. Besides, the thickness of the half ring between the second area and the rear surface <NUM> decreases when going from the second lateral portion 42b to the shoulder <NUM>. The second area <NUM> is in the shape of a crescent, as better illustrated in <FIG>. The second area <NUM> is larger in the middle of the half ring than at the end portions 40a, 40b. More particularly, the second area <NUM> is machined in the half ring and defines a conical portion. When assembled, the rear surface <NUM> is oriented toward the exchangeable head, and the front surface is oriented toward the tool body.

The first end portion 40a comprises a groove 50a. The second end portion 40b comprises a groove 50b. A first and second through hole <NUM> are provided between the rear surface and the first area at the vicinity of the end portions for receiving a first and a second attachment pin <NUM>. The pins <NUM> enable to connect springs R1, R2 (see <FIG> and <FIG>) to the half rings 34a, 34b. The springs R1, R2 are pretensioned springs and they enable an automatic return of the half rings in a locking position. The springs R1, R2 are for instance springs as depicted in <FIG>.

The half rings 34a, 34b are for instance made of metal.

As previously mentioned, the half rings 34a, 34b are arranged within the quick coupling system <NUM> facing each other. More particularly, the lateral portions 42a, 42b are facing each other. For instance, the concave side of the lateral portions 42a, 42b are facing each other. The lateral surfaces define each two cylindrical surfaces having different main planes. The first end portions 40a are arranged facing each other. The second end portions 40b are arranged facing each other. The rear surfaces <NUM> extend for instance in the same plan.

The actuation unit <NUM> partly extends between two end portions 40a, 40b of the half rings 34a, 34b, as notably seen in <FIG> and <FIG>. More particularly, the actuation unit <NUM> comprises a first actuation part <NUM> and a second actuation part <NUM>. The first and second actuation parts <NUM>, <NUM> are identical. The first and second actuation parts <NUM>, <NUM> are each one-piece elements. The first and second actuation parts <NUM>, <NUM> each comprises a first actuation segment 60a and a second actuation segment 60b. The first actuation segment 60a longitudinally extends in a direction radial to the tool axis X. The second actuation segment 60b extends at a free end of the first actuation segment 60a, on both side of the first actuation segment 60a (see <FIG>, <FIG>). The second actuation segment 60b comprises two free ends, the free ends each engaging with the groove 50a, 50b. The second actuation segment 60b has a curved shape, and its end surfaces (at its free ends) have an inclination which corresponds to the inclination of the end portions 40a, 40b of the half rings 34a, 34b. More particularly, the second actuation segment 60b extends between the first end portions 40a or the second end portions 40b of the half rings 34a, 34b. The second actuation segment 60b is slidingly engaged in the grooves 50a, 50b. The actuation parts <NUM>, <NUM> thus control the position of the locking unit <NUM>. The half rings 34a, 34b will remain in the locking position or will be forced in the released position depending on the position of the second actuation segments 60b within the grooves 50a, 50b.

The quick coupling system comprises a housing <NUM>. The housing <NUM> is fixedly connected to a free end of the tool body <NUM>, and the locking and actuation units <NUM>, <NUM> are movingly arranged within the housing <NUM>. More particularly, the housing <NUM> may have a cylindrical shape defining an opening and two lateral recesses 64a, 64b adapted to receive the first actuation segments 60a. The recesses 64a, 64b are for instance arranged opposite each other, as better seen in <FIG> and <FIG>. The actuation unit <NUM> and the locking unit <NUM> are movable with regard to the housing <NUM>. An internal groove may be provided on the housing <NUM> to receive the half rings 34a, 34b, notably in the released position.

The quick coupling system is symmetrical with a mirror symmetry with regard to a plan orthogonal to the tool axis.

The first actuation segments 60a interact with a sliding sleeve <NUM>. The sleeve <NUM> is arranged around the housing <NUM>. The sleeve <NUM> is movable along the tool axis X. The sleeve <NUM> comprises an internal surface facing the quick coupling system and an external surface, opposite the internal surface. The internal surface is provided with a slope <NUM>. More particularly the internal surface comprises a sloped groove <NUM>. For instance, two sloped grooves <NUM> are provided. The two sloped grooves are arranged opposite each other. The first sloped groove is arranged facing the first actuation part. The second sloped groove is arranged facing the second actuation part. The sleeve <NUM> controls the position of the actuation unit <NUM>. For instance, the sleeve <NUM> is connected to the first actuation segments 60a, as better seen in <FIG> and <FIG>. Each first actuation segment 60a comprises a guiding pin <NUM> attached at its free end (opposite the second actuation segment). A first guiding pin <NUM> is provided on the first actuation part, and a second guiding pin <NUM> is provided on the second actuation part. The guiding pin <NUM> is arranged in the sloped groove <NUM> provided on the sleeve <NUM>. The sleeve <NUM> is movable along the tool axis X, wherein the actuation unit <NUM> and the locking unit <NUM> are movable in the radial direction. The first actuation segments 60a interact with the sleeve <NUM> such that during a translation of the sleeve <NUM>, the guiding pins <NUM> slide along the slopes <NUM>, resulting in the actuation parts <NUM>, <NUM> moving radially toward the axis tool X between a rest position and an active position. In the rest position, the guiding pin <NUM> is positioned in the sloped groove <NUM> at a first end <NUM>. In the active position, the guiding pin is positioned in the sloped groove at the second end <NUM>. An abutment <NUM> may be designed between the housing <NUM> and the sleeve <NUM>. An elastic element may be provided between the sleeve <NUM> and the housing <NUM>, such that the sleeve <NUM> is forced in a position, in which the guiding pin <NUM> remains at the first end <NUM>. In order to move the actuation unit <NUM> from the rest position to the active position, a user has to slide the sleeve <NUM> against the force of the elastic element. Thus, an automatic return of the sleeve is realized. In other words, the rest position is a stable position, wherein the active position is an unstable position. In another embodiment, the sleeve may be forced in the rest position without elastic element provided between the sleeve and the housing. For instance, springs R1, R2 force the half rings in the locking position which forces the actuation unit and the sleeve <NUM> in the rest position. The automatic return of the sleeve is realized through this springs R1, R2. However, in another embodiment, both rest and active positions may be stable positions.

The main piston <NUM>, and more particularly its piston pin <NUM> is arranged concentrically to the quick coupling system <NUM> and along the tool axis X. The piston pin <NUM> is axially movable along the tool axis X and comprises a recess <NUM> arranged at the free end of the piston pin <NUM>. A spring <NUM> is arranged in the recess <NUM> and a mushroom piston <NUM> interferes with the spring <NUM>. The mushroom piston <NUM> partly protrudes from the piston pin <NUM>, notably when the spring <NUM> is in a rest position. The mushroom piston <NUM> is movable along the tool axis X.

The device <NUM> further comprises a pressure relief valve <NUM> connected to the cylinder <NUM>. The pressure relief valve <NUM> is detailed notably on <FIG>. The pressure relief valve <NUM> is used to perform a fluid return function.

More particularly, the pressure relief valve <NUM> comprises a valve body <NUM>, a fluid circulation channel <NUM>, a needle <NUM> and a seat <NUM>. The needle <NUM> is movable relative to the valve body <NUM> between a closed position in which the needle <NUM> is in contact with the seat <NUM> in order to close the channel and an open position in which the needle is at a distance from the seat in order to allow fluid to circulate in the channel <NUM>. The seat <NUM> is movable relative to the valve body so that, as soon as fluid circulates in the channel because of the movement of the needle to the open position, the fluid causes a movement of the seat <NUM> relative to the valve body <NUM> that tends to move the seat away from the needle and prevents the seat from returning towards the needle, in order to maintain the circulation of fluid in the channel. By virtue of the movable seat <NUM>, the pressure relief valve remains open as long as fluid is circulating in the channel, which allows complete evacuation of the fluid contained in the cylinder of the main piston. Thus, the fluid returns automatically and rapidly to the reservoir as soon as the pressure in the cylinder has reached a predetermined pressure threshold. The pressure relief valve and how said pressure relief valve cooperates with the main piston <NUM> is more particularly detailed in <CIT>.

The quick coupling system <NUM> is provided for engaging and securing the exchangeable head <NUM> to the device <NUM>.

The exchangeable head <NUM> comprises a functional part <NUM>. For example, the exchangeable head <NUM> is a crimping head and the functional part <NUM> includes dies. In another embodiment the exchangeable head <NUM> is a cutting head and the functional part <NUM> includes blades or jaws. More generally, the functional part <NUM> is adapted to be actuated by the main piston in order to apply a force on an element (a cable, for example).

Opposite the functional part <NUM>, the exchangeable head <NUM> comprises an interface part <NUM> for its coupling to the device <NUM>. The interface part <NUM> is adapted to be inserted inside the housing <NUM>. The interface part <NUM> may comprise a shoulder <NUM> adapted to abut the housing <NUM>.

The interface part <NUM> is designed to engage with the quick coupling system <NUM>. More particularly, the interface part <NUM> comprises a circular groove <NUM> adapted to receive the locking unit <NUM>. The circular groove <NUM> receives the first and the second half rings 34a, 34b when said half rings are in the locking position. The circular groove <NUM> is formed by a bottom <NUM>, a first and a second lateral wall <NUM>, <NUM>. In a cross-section, the first wall <NUM> extends sensibly orthogonal from the bottom <NUM>, wherein the second wall <NUM> is inclined with regard to the first wall <NUM>. The inclination of the second wall corresponds to the inclination of the second area <NUM> of the half rings 34a, 34b.

The interface part <NUM> further comprises on its free end adapted to be directed toward the device a chamfer <NUM>. The chamfer <NUM> allows an easy insertion of the interface part <NUM> within the housing <NUM>, but most importantly it allows to radially push the locking unit <NUM> from its locking position toward its released position.

An interface recess <NUM> is provided at the end of the interface part <NUM>. The recess <NUM> is adapted to receive the mushroom piston <NUM> and a portion of the piston pin <NUM>. Thus, the motion of the main piston <NUM> may be transferred to the functional part <NUM> of the head in order to impress a force to an element. For instance, the head comprises a head piston <NUM> which interacts directly with the piston pin.

<FIG> are exemplary exchangeable heads <NUM> which could be used with the device <NUM>. More particularly, <FIG> shows a crimping head adapted to be engaged to the device. In <FIG>, the exchangeable head is a knockout head adapted to punch holes in metal sheets. <FIG> shows a scissor head. <FIG> depicts a din rail cutter head (or strut channel cutter head). <FIG> shows a strut rail cutter head. The exchangeable heads in <FIG> work according to similar principles. In other embodiments (not shown), the exchangeable head may be a crimping head, a dieless crimping head or a conventional cutter head.

<FIG> is a perspective view of the head of <FIG>. More particularly, <FIG> shows a shearing exchangeable head <NUM>, notably adapted for shearing (or cutting) strut channels or rails. The exchangeable head <NUM> comprises a functional part <NUM> with a first die <NUM> and a second die <NUM>. The first die <NUM> is movable with regard to the second die <NUM>. The second die <NUM> is fix with regard to a frame <NUM> of the head. The first die <NUM> is movable with regard to the frame <NUM>. The exchangeable head <NUM> further comprises a force multiplier unit <NUM>, as better illustrated in <FIG>. The force multiplier unit <NUM> comprises a head cylinder <NUM>. The head cylinder <NUM> comprises a first section <NUM> with a first diameter D1. A first head piston <NUM> is arranged within the first section <NUM>. The head cylinder <NUM> comprises a second section <NUM> with a second diameter D2. The second diameter D2 is greater than the first diameter D1. A second head piston <NUM> is arranged within the second section <NUM>. The first head piston <NUM> extends between the second head piston <NUM> and the main piston <NUM> (and mushroom piston) when the head <NUM> is connected to the device <NUM>. A shoulder <NUM> is provided between the first section <NUM> and the second section <NUM>.

The first head piston <NUM> comprises a first head piston surface <NUM> which is facing the mushroom piston and the main piston <NUM> when the exchangeable head <NUM> is secured to the device <NUM>. The first head piston <NUM> is actuated directly by the main piston. The first head piston <NUM> comprises a first piston rod <NUM> extending toward the second head piston <NUM>. The second head piston <NUM> comprises a second head piston surface <NUM> and a second piston rod <NUM>. The second head piston surface <NUM> is arranged facing the first section <NUM>. In the rest position, the second head piston surface <NUM> may abut against the shoulder <NUM>. The second head piston surface <NUM> is provided with a second head recess <NUM> in which the first piston rod <NUM> can be guided.

The first head piston surface is adapted to slide within the first section (notably through the action of the main piston, as explained in more detail below). The first section comprises fluid, notably oil. The first head piston surface is adapted to move toward the second head piston, thus compressing the fluid provided in the first section. The compressed fluid applies a force on a second head piston surface. For instance, the first piston rod <NUM> does not forward any translation motion to the second head piston <NUM>. The translation motion of the second head piston <NUM> is realized through the force applied by the fluid provided and compressed in the head cylinder <NUM>.

The second piston rod <NUM> directly interacts with the first die <NUM> and thus moves the first die <NUM>. The ratio between the first and second diameters allows to increase the compression force generated by the second head piston <NUM>. The stroke of the first head piston is the twice the stroke of the second head piston.

The first die <NUM> and the second die <NUM> each defines a profile (or opening) sized and shaped to receive a strut channel inserted therein. The profile or opening extends through the dies <NUM>, <NUM>. In another embodiment, as seen notably in <FIG>, the dies may define several profiles (or openings) sized and shaped to receive strut channels having different dimensions.

Referring to <FIG>, the first die <NUM> is shown with openings <NUM>, the second die <NUM> is shown with openings <NUM>. The size and shape of the openings in the pair of dies are the same or substantially the same. In a rest position, the first and second dies <NUM>, <NUM> are next to each other, the openings of the first die facing the opening of the second die. A strut channel (not represented) can then be inserted through the openings. In order to shear the strut channel, the first die <NUM> is moved by the first head piston and second head piston, wherein the second die <NUM> remains fix. Therefore, a shearing force is applied to the strut channel. The shearing force enables cutting the strut channel without any metal filings.

A spring <NUM> may be provided between the frame <NUM> and the second head piston in order to move the second head piston automatically back to its rest position when no forces are applied on the first and second head pistons. In the rest position, the dies are back in a first position where the openings of the first die face the openings of the second die.

As seen in <FIG>, a support arm bracket <NUM> is provided. The arm bracket may comprise a recess adapted to receive the strut channel (or rail). The arm bracket may be removably connected to the frame of the exchangeable head. The support arm bracket <NUM> prevents a rotation of the strut channel during the shearing, in order to provide a clear cut.

The exchangeable head of <FIG> is similar to the exchangeable head of <FIG>, as already mentioned. More particularly, the dies in <FIG> are different than the dies in <FIG> in than they are provided with more openings shaped to different rail or strut channels sizes. The exchangeable head of <FIG> is for example adapted to cut four (<NUM>) different DIN rails, a threaded rod (for instance a M6 threaded rod), two different bus bars and the punching of rails or strut channels with its hole punching area P. A rail length adjustment can be provided on the exchangeable head for successive cuts.

In order to form a hydraulic tool <NUM> adapted to perform an operation on an element, a user shall first select the exchangeable head <NUM> corresponding to the action to be performed and to the dimensions of the element. Once the exchangeable head <NUM> has been selected, exchangeable head <NUM> and device <NUM> are aligned such that the interface part <NUM> of the exchangeable head <NUM> faces the quick coupling system <NUM> and a longitudinal axis of the exchangeable head <NUM> is aligned with the tool axis X, as notably seen in <FIG>. Exchangeable head <NUM> and device <NUM> are moved toward each other such that the chamfer <NUM> enters an opening defined by the housing and contacts the half rings 34a, 34b, as depicted in <FIG>. More particularly, the chamfer first contacts the rear surface of the half rings 34a, 34b.

As seen in <FIG>, the exchangeable head <NUM> further moves toward the device <NUM> and the chamfer <NUM> pushes the half rings 34a, 34b from their locking position toward a released position. The half rings 34a, 34b then slide on a segment of the interface part <NUM> arranged between the chamfer <NUM> and the circular groove <NUM> until the half rings 34a, 34b are arranged facing the circular groove <NUM> (see <FIG>). When the half rings34a, 34b are arranged exactly facing the circular groove <NUM>, no further effort apply on the half rings and they are automatically forced back in the locking position and within the circular groove <NUM>. The half rings thus extend in the circular groove.

In order to ensure the correct engagement of the exchangeable head and the device, a pushing force of at least <NUM> daN, and in particular of at least <NUM> to <NUM> daN is required.

More particularly, as seen in <FIG>, during the insertion of the exchangeable head <NUM>, the surface of the head piston (or another surface of the head) first contacts the surface of the mushroom piston <NUM> and the mushroom piston <NUM> is further pressed by the exchangeable head <NUM> until it abuts against the main piston pin <NUM>. Once the mushroom piston <NUM> abuts against the main piston pin <NUM>, the exchangeable head <NUM> can be further moved inside the device <NUM> such that the half rings 34a, 34b engage the circular groove <NUM>. The mushroom piston <NUM> thus ensures a secure engagement. The mushroom piston <NUM> ensures also a tolerance compensation. Besides, the mushroom piston enables the disengagement of the exchangeable head.

<FIG> show more precisely the engagement of the half rings 34a, 34b within the circular groove <NUM>. As seen in <FIG>, the second area <NUM> of the half rings 34a, 34b cooperates with the inclined wall <NUM> of the circular groove <NUM>. A functional gap G is provided. More particularly, the circular groove <NUM> is larger than the thickness of the half rings 34a, 34b. Thus, when inserted inside the circular groove, the functional gap G arises. When a force F (see <FIG>) along the tool axis and in a direction opposite the device is applied to the exchangeable head <NUM>, the inclined wall <NUM> of the circular groove pushes the half rings 34a, 34b such that an angle A is created between the rear surface <NUM> of the half rings 34a, 34b and the wall of the recess provided in the housing <NUM>. This hook shape with inclined surfaces allows to avoid the exchangeable head (and notably the circular groove) to be damaged when secured to the device. Besides, this particular shape allows to squeeze the half rings and thus increase the locking forces of the half ring within the circular groove. Indeed, with flat surfaces, the half ring could inadvertently escape from the circular groove. The inclined surfaces and the shoulder overcome this issue.

For disengaging the exchangeable head <NUM> from the device <NUM>, a user can slide the sleeve <NUM> in a direction opposite the exchangeable head <NUM>, as notably depicted in <FIG> and <FIG>.

In <FIG>, the locking unit <NUM> is in the locking position and the actuation unit <NUM> in the rest position. The sleeve <NUM> abuts against a shoulder of the housing <NUM>.

The guiding pin <NUM> is arranged in the sloped groove <NUM> of the sleeve, and more particularly at an endpoint <NUM> of the sloped groove such that the actuation parts <NUM>, <NUM> extend at a distance from the tool axis X which is greater than in their active position. As seen in <FIG>, the second actuation segments 60b of the actuation parts <NUM>, <NUM> are partly engaged in the groove 50a, 50b provided on the half rings 34a, 34b, but no constraint is applied to the half rings. For instance, as depicted in <FIG>, the inside corners of the half rings 34a, 34b contact each other.

In order to move the half rings 34a, 34b from the locking position to the released position, the user slide the sleeve <NUM> according to arrow S (see <FIG>), thus the guiding pin <NUM> slides inside the sloped groove <NUM> and by sliding, the distance between the guiding pin <NUM> and the tool axis X decreases. Thus, the distance between the actuation parts <NUM>, <NUM> and the tool axis X also decreases, as better seen in <FIG>. The linear motion of the sleeve <NUM> along the tool axis X causes the translation of the actuation parts <NUM>, <NUM> in the radial direction toward the tool axis X. During the translation of the actuation parts <NUM>, <NUM> in the radial direction toward the tool axis, the half rings 34a, 34b are pushed apart from each other. Indeed, the second actuation segments 60b slide within the grooves 50a, 50b of the half rings causing the half rings 34a, 34b to move apart in the radial direction opposite the tool axis (See <FIG>) until the half rings do not extend inside the circular groove <NUM> anymore. Actually, the sleeve <NUM> moves until the guiding pin <NUM> reaches an end position in the sloped groove <NUM>. The end position correspond to the release position of the locking unit <NUM>. The half rings 34a, 34b are at a non-zero distance from the circular groove and the head can be released or disengaged from the device <NUM>. The released position of the locking unit <NUM> is not a stable position, as mentioned before. In other words, the user shall continue to apply an effort on the sleeve in order to maintain the half rings in the released position. Once the user release the effort on the sleeve, an automatic return of the sleeve and the locking unit and actuation unit in the locking position and the rest position is realized. The locking position is a stable position.

In another embodiment, the released and the locking positions could be stable positions. A hook or switch may be provided to maintain the sleeve in a position, in which the actuation unit is forced in the active position (and thus the locking unit is forced in the released position).

Claim 1:
Device (<NUM>) having a quick coupling system (<NUM>) for fastening an exchangeable head (<NUM>) comprising:
- a tool body (<NUM>) with a cylinder, wherein a main piston (<NUM>) is capable of being moved inside the cylinder under the effect of an injection of pressurised fluid into the interior of the cylinder, the tool body (<NUM>) extending longitudinally along a tool axis (X);
- the quick coupling system (<NUM>) arranged at a free end of the tool body (<NUM>) wherein the quick coupling system (<NUM>) is with: an actuation unit (<NUM>), and a locking unit (<NUM>) adapted to secure the exchangeable head (<NUM>) to the tool body (<NUM>),
wherein the locking unit (<NUM>) is actuated by the actuation unit (<NUM>) between a locking position and a release position,
wherein in the locking position the locking unit (<NUM>) is adapted to secure the exchangeable head (<NUM>) to the tool body (<NUM>), such that transmission forces can be exchanged between the exchangeable head (<NUM>) and the piston, and
wherein in the released position the locking unit (<NUM>) is adapted to release any force applied to the exchangeable head (<NUM>) in order to remove the exchangeable head (<NUM>), and characterised in that
the locking unit (<NUM>) comprises a first and a second half ring (34a, 34b), wherein the half rings are radially movable between the locking position and the released position, and and in that
the quick coupling system (<NUM>) further comprises a sleeve (<NUM>) slidingly arranged around the quick coupling system (<NUM>), the sleeve (<NUM>) being movable along the tool axis (X), and the actuation unit (<NUM>) is connected to the sleeve (<NUM>) and adapted to be radially moved by the sleeve (<NUM>) from a rest position to an active position, wherein in the rest position the half rings (34a, 34b) are in the locking position, and in the active position, the half rings (34a, 34b) are forced in the released position.