Crimping Tool

Abstract

The present invention relates to a crimping tool, in particular crimping pliers. The crimping tool comprises crimping die halves having a resilient deformation region. At the end of a crimping process the resilient deformation region is elastically deformed with the result that the crimping contour opens and contour parts automatically move apart. Accordingly, the crimping contour “breaks free” from the work piece for an ease of the removal of the work piece from the crimping tool.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to co-pending German Patent Application No. DE 10 2009 001 949.9 entitled “Gesenkhalfte and Presswerkzeug”, filed Mar. 27, 2009.

FIELD OF THE INVENTION

The present invention generally relates to a crimping tool which might be driven by hand or by a hydraulic, an electrical or any other drive and which is used for crimping a work piece. Without restricting the invention to the following examples, the work piece might be a fitting for connecting tubes or conduits, a cable shoe, a sleeve for an end of a cable, a plug, a crimp connection without lead, a double connection for a wire and an insulation of the wire, a socket or a connecting element for an electrical cable or an optical fiber cable.

BACKGROUND OF THE INVENTION

When using crimping tools, it might happen that the work piece keeps attached or sticks to the crimping contour of the crimping die halves at the end of the crimping process. To remove or eject (in the following “eject”) the work piece, removing forces have to be applied upon the work piece. However, such removing forces might lead to damages of the work piece. It is possible that by means of the removing forces the crimped connection is disconnected or the surface of the crimped contour of the work piece is damaged so that the produced surface contour differs from the intended surface contour. In case of the work piece being part of a wiring harness, these damages lead to increased costs and/or increased efforts for adjusting these damages.

The cause for the undesired sticking forces between work piece and crimping die half might be explained as follows:

• • crimping die halves for crimping work pieces generally comprise a crimping contour that contacts the work piece during the crimping process both with contact surfaces directed transverse to the crimping axis as well as contact surfaces being slanted with respect to the crimping axis. The slanted contact surfaces lead to slanted crimping forces directed vertical to the slanted contact surfaces. These slanted crimping forces have one force component directed coaxially to the crimping axis and one force component directed transverse to the crimping axis. Accordingly the slanted contact surfaces also crimp the work piece in a direction lateral to the crimping axis during the crimping process. The lateral crimping forces lead to plastic and elastic deformations of the work piece. At the end of the crimping process, the elasticity of the work piece results in the work piece being clamped transverse to the crimping axis within the crimping contour, i.e. between the slanted contact surfaces. The same effect also occurs in case of the crimping die halves being built with crimping contours having a curved shape. The aforementioned effect increases with a reduction of the angle between the slanted surfaces and the crimping axis.
  • Another explanation of the undesired “sticking effect” might be that during the crimping process microscopic or macroscopic surface asperities of the crimping die halves and the work piece engage with each other.
  • Furthermore, it might be possible that in a micro scale welded joints are established between the surface asperities.

For avoiding the “sticking effect”, it is known to add lead to the base material or a surface layer of the work piece wherein the lead is used as a type of lubricant in order to ease the removal of the work piece. However, the use of lead is to be restricted. E.g., the European guideline EU 2002/95/EG prescribes to restrict the use of dangerous material in electronic devices. The European guideline includes also regulations for the avoidance of the use of heavy metals as lead. According to the aforementioned European guideline, work pieces as sleeves, plugs or sockets from Jul. 1, 2006 on should not contain any lead. Known solutions for avoiding the “sticking” effect without the use of lead comprise the adaption of the crimping contour, the smoothing the surface asperities of the crimping contour and the work piece as well as a modification of the chosen materials for the work piece and the crimping die halves. However, it has turned out that these solutions per se are not satisfactory.

Accordingly, it is an object of the present invention to provide a crimping tool avoiding or at least reducing the aforementioned problems involved with the explained “sticking effect” and the need for applying removal forces upon a work piece.

SUMMARY OF THE INVENTION

The present invention relates to a crimping tool comprising two crimping die halves. The crimping tool might be of any type, in particular with a manual drive by means of hand levers, a hydraulic drive, an electric drive and the like. Furthermore, the crimping die halves might be fixed at the crimping tool or might be displaceable or exchangeable. Furthermore, it is possible that a crimping die half builds an integral part of a crimping jaw or is built separately from the crimping jaw but actuated by the crimping jaw. Furthermore, the term “crimping die half” does not mean that the crimping contours of the “crimping die halves” are necessarily symmetrical or really build one half of the overall crimping contour.

For crimping die halves according to the prior art, the person with skill in the art tried to build the crimping die half with its crimping contour as stiff and hard as possible in order to avoid deformations of the crimping contour during the crimping process. These deformations of the crimping contour were generally undesired due to the fact that such deformations have the result that at the end of the crimping process the produced contour of the work piece deviates from the desired contour. Surprisingly, the present invention leaves the aforementioned route of the person with skill in the art by building the crimping die half not completely stiff, hard and rigid. Instead, according to the invention, a movement, pivoting or spreading of parts of the crimping die half and the related crimping contour is to some extent desired, at least only at the end of the crimping process. By means of such elastic movement, the crimping die half is transferred from a crimping state to an ejection state. In the ejection state, the distance of the contour parts transverse to the crimping axis or the angle between the contour parts has increased with respect to the crimping state. In case of the work piece at the end of the crimping process being clamped with the crimping contour or sticking at the crimping contour, the inventive movement or spreading of parts of the crimping contour leads to a “breathing effect” of the crimping contour with an enlargement of the crimping contour transverse to the crimping axis. This “breathing effect” results in the work piece at least partially breaking free from the crimping contour. Accordingly, for the inventive crimping tool, the forces required for removing the work piece from the crimping die halves is reduced.

In general, also for a stiff crimping die half according to the prior art in a micro scale the crimping contour might be spread throughout the crimping process. According to the invention, the movement or spreading of the parts of the crimping contour occurs at the end of the crimping process within a second region of the distances of the crimping die halves. In particular contour parts of the crimping contour being slanted with respect to the crimping axis break free from the outer surface of the work piece building a microscopic or macroscopic gap. For one embodiment of the invention ejection force region only come into contact in the second region of distances. It is also possible that in this second region of distances the work piece is still to some extent crimped in the direction of the crimping axis whereas at the same time caused by forces applied to the ejection force regions the lateral surface or slanted surfaces of the crimping contour move out of contact with the work piece in the lateral direction. Additionally, or in an alternative embodiment, it is possible that for building a gap between the work piece and the crimping contour in the ejection state a shear movement occurs between parts of the crimping contour and the outer surface of the work piece. This shear movement might also lead to the effect that the work piece breaks free from the crimping contour.

According to another embodiment of the crimping tool, the movement or spreading for transferring the crimping contour from the crimping state to the ejection state in the second region of distances is increased with respect to a movement or spreading during the crimping process in the first region of distances of the crimping die halves. There is a plurality of possibilities for providing the movement of parts of the crimping die halves: according to a first embodiment of the invention, the movement or spreading is provided by the resilient deformation region of the crimping die half. E. g., it is possible that the crimping die half is built by an integral piece of metal comprising the resilient deformation region which might be built by a local weakening of the crimping die half and its cross-section. However, it is also possible that one crimping die half is built by two or more parts adhered with each other. According to one embodiment, the crimping die half is built with two parts made of metal linked by a resilient intermediate part or intermediate layer of another material which is attached to or bonded with the other parts. According to another embodiment of the invention, the crimping die half during the spreading or movement for transferring the crimping contour from the crimping state into the ejection state is subjected to a bending moment. In an idealized or simplified view, the crimping die half might be approximated as a beam in bending, having a longitudinal axis with an orientation transverse to the crimping axis (cp. FIGS. 7 and 8). For such a beam in bending the geometrical moment of inertia of a cross-section of the crimping die half is reduced in the region of the crimping contour leading to the desired spreading effect caused by the resilient bending.

For a further embodiment of the crimping tool, the crimping die half comprises at least one recess or bore located behind the crimping contour when seen along said crimping axis. The recess or bore might have a circumferentially closed or open cross section. The recess or bore leads to a weakening of the crimping die half by a reduction of the geometrical moment of inertia for providing the desired spreading movement. It is also possible that a recess or bore built in the base material of the crimping die half is filled with another material having a reduced stiffness.

In the first region of distances of the crimping die halves, the main or only contact between the crimping die halves is built at the contact surface of the crimping contours with the work piece. These contacts lead to surface pressures having the effect that gaps built between the crimping contour and the work piece, also due to any micro deformations of the crimping contour, are at least partially filled by the plastically deformed material of the work piece with proceeding crimping process. At the end of the first step of the crimping process, so at the end of a first region of distances of said crimping die halves, there are no gaps between the crimping contour and the work piece. For another embodiment of the invention, at the end of the first crimping step, so at the end of a first region of distances, ejection force regions come into play being responsible for transferring the crimping die halves from the crimping state into the ejection state. At the ejection force regions ejection forces (in particular a pair of ejection forces) are (is) applied. The mechanical background of this embodiment of the invention is explained on the basis of the following simple example (whereas also more complex stresses of the material, shapes of the crimping contour and the ejection force regions are possible): assuming a crimping contour being symmetrical to the crimping axis surface pressures applied to the crimping contour lead to a resulting force running centrally through the crimping contour and having an orientation along the crimping axis. In case of supporting the crimping die half, e.g. at the crimping jaw or other parts of the crimping tool at a location on the line of action of the resulting force and opposite to the crimping contour, the crimping die half (simplified as a beam subjected to bending) is only subjected with forces having no or a reduced significant lever arm (see FIG. 7). Accordingly, for this configuration no significant displacements or bending occurs. However, for the transition from the first region of distances of the crimping die halves to the second region of distances of the crimping die halves the ejection force regions come into contact with counter surfaces of the other crimping die half or another element of the crimping tool. Due to the fact that the ejection force regions are located distant from the crimping contour, ejection forces applied upon the ejection force regions have a significant lever arm leading to a bending moment acting upon the bending beam. This bending leads to a spreading or increased spreading of the crimping contour (see FIG. 8). For increasing this spreading effect, it is possible to increase the ejection forces applied and/or to increase the distance of the ejection force regions from the crimping contour in a direction transverse to the crimping axis.

For another embodiment of the invention, the ejection regions have a contact surface being slanted with respect to the crimping axis. The inclination angle of the contact surface might be chosen to direct the ejection forces applied to the ejection force regions with an optimal angle for causing an increased bending or spreading movement. Furthermore, by means of the slanted contact surfaces a kind of wedging connection is used resulting in an amplification of the applied ejection force in a desired direction.

For another crimping tool according to the invention, the elastic deformation of the resilient deformation element is at least partially blocked in the first region of distances by a blocking or fixing element which is designed and configured for at least partially filling a recess of the crimping die half in the crimping state but being located without contact to the recess in said ejecting state. The blocking or fixing element blocks the spreading movement of the crimping contour temporarily during the main crimping process whereas the recess is “freed” for a transfer of the crimping contour from the crimping state to the ejection state. It is also possible that the resilient deformation regions are “switched” from a rigid configuration to a resilient configuration at the transfer from the first region of distances to the second region of distances by removing the fixing or blocking element. Furthermore it is possible that the fixing element is manually activated for crimping processes of the crimping tool with a first type of crimping die halves and/or work pieces. For a second type of crimping die halves and/or work pieces, the fixing element is manually removed. Furthermore, it is possible that the fixing element is coupled to a drive of the crimping tool such that the fixing element is automatically transferred from a blocking position to a non-blocking position when using the drive. It is also possible that the fixing element is manually transferred by the user by means of a suitable manipulation element being independent upon other drive elements of the crimping tool, in particular independent on hand levers.

The fixing element might have a fixing surface contacting the recess of the crimping die half and introducing a fixing force counteracting a deformation of the resilient deformation element. It is possible that the fixing element enters with the fixing surface into the recess of the crimping die half for at least reducing the weakening of the crimping die half built by the recess in the crimping state. In other words, the fixing element blocks with the fixing surface the spreading degree of freedom of the crimping die half.

Whereas for the embodiments described above, the invention is embodied in crimping die halves having one single crimping contour, it is also possible that the invention is used for crimping die halves having a plurality of crimping contours for crimping work pieces having different geometries. For these embodiments, the crimping contours build a plurality of nests for different work pieces.

Here, the aforementioned measures are used for providing that only one nest of the plurality of nests which is actually used for crimping the work piece is elastically deformed or that all of the nests are elastically deformed when crimping one single work piece in one single nest of the plurality of nests. It is possible that the crimping die half is fixed at a crimping jaw or locked or rested with the crimping die half similar to DE 201 00 031 U1 independent on the nest presently used. Furthermore, it is possible that the crimping die half is an integral part built by the crimping jaw, see U.S. Pat. No. 4,794,780. Furthermore, it is possible that the crimping die half might be used in two different orientations with the crimping tool differing by a rotation of 180°. Furthermore, the inventive measures might also be used in connection with crimping die halves being usable in a plurality of operational states with respect to the other components of the crimping tool as described in US 2009/0217791 A1.

The spreading movement for transferring the crimping contour from the crimping state to the ejection state might be caused by the main drive element used for causing the crimping movement, e.g. the hand levers, a hydraulic drive or an electric drive. However, it is also possible that the spreading movement is caused by additional drive elements not being responsible for the crimping process itself. To mention only one example without restricting the present invention to this embodiment, a knurled wheel might be manually activated. The force applied upon the knurled wheel is transferred to the crimping die half via a transmission increasing said force or the knurled wheel is linked with a wedge entering a wedge-like recess of the crimping die half for blocking or causing the spreading movement.

Other features and advantages of the present invention will become apparent to one with skill in the art upon examination of the following drawings and the detailed description. It is intended that all such additional features and advantages be included herein within the scope of the present invention, as defined by the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. In the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a schematic view of a crimping die half used in the inventive crimping tool comprising two parts of the crimping die halves being moved in lateral direction versus each other.

FIG. 2 is a schematic view of a crimping die half for an inventive crimping tool wherein two parts of the crimping die halves are pivoted versus each other.

FIG. 3 is a schematic view of a crimping die half used in inventive crimping tools comprising a resilient deformation region.

FIG. 4 is a schematic view showing the use of two crimping die halves having recesses and ejection force regions in a crimping tool during the main crimping process and for a first region of distances of the crimping die halves.

FIG. 5 is a free body diagram of the crimping die halves of FIG. 4 during the main crimping process or in the first region of distances of the crimping die halves.

FIG. 6 is a free body diagram of a crimping die half according to FIG. 4 during the spreading movement at the end of the main crimping process or in the second region of distances of the crimping die halves.

FIG. 7 shows the surface pressures during the main crimping process or in the first region of distances of the crimping die halves for a simplified mechanical model of the crimping die half as a bended beam.

FIG. 8 shows the acting surface pressures at the end of the main crimping process or in the second region of distances of the crimping die halves during the spreading movement for the simplified mechanical module of the crimping die half according to FIG. 7.

FIG. 9 shows schematic views of the crimping contour in a crimping state and an ejection state.

FIG. 10 is a schematic view of a crimping die half with a recess having a circumferentially open cross-section and alternative or cumulative positions for locating the ejection force regions for applying ejection forces causing the spreading movement.

FIG. 11 is a schematic view of the cooperation of crimping die halves in ejection force regions for spreading at least one of the crimping die halves.

FIG. 12 is a schematic view showing the interaction of a crimping die half with a blocking or fixing element for temporarily blocking or fixing or locking a spreading degree of freedom.

FIG. 13 is a schematic view of a crimping die half during the process of crimping a fitting or connection for tubes or conduits.

DETAILED DESCRIPTION

The invention relates to a crimping tool, in particular crimping pliers 1, with any drive mechanism, in particular manually activated hand levers or an electric or hydraulic drive. The crimping pliers 1 (besides the inventive features described in the following) might have any design or construction known from prior art. In particular, the crimping pliers 1 might have activation mechanisms, a force locking unit, a locator or a head of the pliers or other constructive details known from crimping pliers distributed by the present applicant, in particular known from documents U.S. Pat. No. 4,794,780, U.S. Pat. No. 5,153,984, EP 0 471 977 B1, U.S. Pat. No. 5,187,968, DE 44 27 553 C2, U.S. Pat. No. 5,913,933, DE 197 09 639 A1, DE 197 53 436 C2, U.S. Pat. No. 6,053,025, U.S. Pat. No. 6,026,671, DE 298 03 336 U1, U.S. Pat. No. 6,155,095, DE 198 34 859 C2, U.S. Pat. No. 6,286,358, U.S. Pat. No. 6,289,712, U.S. Pat. No. 6,474,130, U.S. Pat. No. 6,612,147, U.S. Pat. No. 6,877,228, DE 101 40 270 B4, U.S. Pat. No. 6,910,363, U.S. Pat. No. 7,155,954, DE 10 2005 003 615 B3, DE 10 2005 003 617 B3, US 2009/0044410 A1, US 2008/0163664 A1, US 2009/0183547 A1, US 2009/0217791 A1, US 2009/0249855 A1, DE 20 2008 003 703 U1.

The crimping pliers 1 comprise preferably two crimping die halves 2, 3. The crimping die halves 2, 3 are moved along a straight or curved crimping axis 4 during the main crimping process. The crimping die halves 2, 3 each comprise a crimping contour 5, 6. The crimping contours 5, 6 contact the outer surface of a work piece 7 during the crimping process and elastically deform the work piece 7. In the figures showing different embodiments, elements having an at least partially equivalent function are designated with the same reference numerals. The crimping die halves 2, 3 might be built separately from and exchangeable with respect to the crimping jaws of the crimping pliers 1 or might be an integral part of the crimping jaws.

For the embodiment shown in FIG. 1, one single crimping die half 2 comprises two parts 8, 9 of the crimping die half. The parts 8, 9 of the crimping die halves each comprise crimping contour parts 10, 11 separated by an intermediate crimping contour part or directly abutting each other without a gap or groove in between. In case of the crimping contour 5 being symmetrical to the crimping axis 4, the crimping contour parts 10, 11 are built by the right and left part of the crimping contour 5 seen from the symmetry axis. The parts 8, 9 of the crimping die halves are linked with supporting elements of the crimping tool, in particular with crimping jaws. At least one crimping die part 8, in particular both of the parts 8, 9 of the crimping die halves, are movable with respect to the crimping axis 4 in a transverse direction by elastically deforming a resilient deformation element (not shown). During the main crimping process, i.e. in the first region of distances of the crimping die halves, such elastic degree of freedom is not used such that the crimping contour 5 does not have a gap between the parts 10, 11 of the crimping contour. At the end of this first region of distances, the parts 8, 9 of the crimping die half are moved transverse to the crimping axis 4 so that the parts of the crimping contour 10, 11 increase their distance building a gap. For the schematically shown crimping contour 5, each part 10, 11 of the crimping contour comprises a contour part 15 having an orientation transverse to the crimping axis 4 as well as a contour part 16 being inclined versus a direction transverse to the crimping axis and to the crimping axis 4, here with an angle of inclination of approximately 60°. The spreading caused by the movements 12, 13 leads to a shear movement of the contour part 15 having an orientation transverse to the crimping axis 4 with respect to the outer surface of the work piece 7. The inclined contour parts 16 break free from the outer surface of the work piece 7 establishing a gap between the contour part 16 and the outer surface of the work piece 7. The aforementioned movements ease the removal of the work piece from the crimping die half 2.

For the embodiment shown in FIG. 2, the crimping die halves are linked with each other or with other supporting elements of the crimping pliers 1 by a resilient deformation region shown simplified as a pivot 14. The spreading movement at the end of the main crimping process or for the transfer from the first region of distances to the second region of distances of the crimping die halves is not built by a translatory movement of the parts 8, 9 of the crimping die half but by a pivoting movement 12, 13 around the pivot 14. Such pivoting movement both causes an increase of the distances of the contour parts 10, 11 from each other with the establishment of a gap as well as an increase of the angle between the contour parts 15, 16 of the parts 8, 9 of the crimping die halves.

It is possible that in a realistic embodiment, the resilient deformation region does not lead to a pure translatory movement according to FIG. 1 or a pure pivoting movement according to FIG. 2 but to a superposition of a translatory movement and a pivoting movement.

For the embodiment shown in FIG. 3, the crimping die half 2 is built as one single integral part. Here, the crimping die half 2 comprises a resilient deformation region 17 for spreading the crimping contour 5. The resilient deformation region 17 might be of any design or shape. To name only some examples, the resilient deformation region 17 might be built by a weakening of the material, a decrease of the wall thickness of the crimping die half 2, a recess or the like. Furthermore, it is possible that the crimping die half is built with two parts 8, 9 adhered or bonded with a resilient deformation region 17 built from another material having an increased elasticity (see FIG. 3). As shown in FIG. 3, the resilient deformation region 17 might extend completely over the crimping die half in the direction of the crimping axis such that the resilient deformation region 17 also limits the crimping contour 5. However, it is also possible that the parts 8, 9 of the crimping die half are linked by an integral bar limiting the crimping contour 5, whereas the more elastic material extends on the side opposite to the crimping contour 5 from the bar. For these embodiments, the resilient deformation region 17 is elastically deformed during the spreading movement for transferring the crimping contour 5 from the crimping state into the ejection state.

FIG. 4 shows the cooperation of the crimping die halves 2, 3 during the main crimping process or in the first region of distances of the crimping die halves 2, 3. For this step of the crimping process, the opposing front surfaces of the crimping die halves 2, 3 have a decreasing distance from each other in the direction of the crimping axis. The distance is decreased by driving the crimping tool. For the shown embodiment, the crimping die half 2 is fixed at the head of the pliers, whereas the crimping die half 3 is a moved crimping die performing a translatory crimping movement 18—however, the present invention is not restricted to such an embodiment. The work piece 7 is located between the crimping contours 5 of the crimping die halves 2, 3. During the crimping movement 18, the work piece 7 is more and more plastically deformed and crimped such that the outer contour of the work piece with proceeding crimping movement 18 more and more approximates the shape of the crimping contours 5 of the crimping die halves 2, 3. According to FIG. 4, the crimping die halves 2, 3 comprise protrusions 19, 20. These protrusions are located distant from the crimping axis 4 in a direction transverse to the crimping axis 4. In particular the protrusions 19, 20 are located at the outer end of the crimping die half in lateral direction. The protrusions 19, 20 have an orientation versus the opposing crimping die half. During the first region of distances of the crimping die halves 2, 3 (additionally to the support of the crimping die halves 2, 3 by supporting elements 21, 22 of the crimping pliers 1 for applying the crimping forces) only contact the work piece 7 via the crimping contours 5. For a transition of the first region of distances to the second region of distances of the crimping die halves 2, 3 the ejection force regions 23, 24 built by the front surfaces of the protrusions 19, contact the respective ejection force regions 23a, 24a of the opposing crimping die half. The support of the crimping die halves 2, 3 at the supporting elements 21, 22 of the crimping pliers is located close to or on the crimping axis 4 and extends over the width of the crimping contour 5. It is possible that the supporting elements 21, 22 have a curved or convex shape.

FIG. 5 shows a free body diagram of the crimping die half 2 during the first region of distances of the crimping die halves 2, 3. On the side opposite to the crimping contour 5, the contact stresses due to a support of the crimping die half 2 at the supporting element 22 is given by curve 25. At the opposite side, the surface stresses caused by the contact of the crimping contour 5 with the work piece 7 are given by curve 26. The curves 25, 26 represent surface stresses having resultant forces of the same amount but opposing directions so that these resultant forces and contact stresses cancel out without having a significant lever arm and leading to significant bending moments. (Not shown in the free body diagram are contact stresses acting in the contour parts 16 and having an orientation transverse to the crimping axis 4 or being inclined with respect to the crimping axis 4.)

FIG. 6 shows a corresponding free body diagram in the second region of distances of the crimping die halves 2, 3, wherein the crimping contour 5 is spread apart from the crimping state into the ejection state. In this state, the ejection force regions 23, 24 of the crimping die half contact the respective ejection force regions 23a, 24a of the crimping die half 3 with ejection forces 27, 28 having a lever arm 29 with respect to the crimping axis 4 and the center of the crimping contour 5. By means of dimensioning in particular

• • the extension of the protrusions 19, 20 along the crimping axis 4,
  • the distance of the edges of the crimping contours 5 of the crimping die halves 2, 3 at the transition point from the first region of distances to the second region of distances and
  • the resilient properties of the resilient deformation region

the amount of deformation and opening or breathing of the crimping contour 5 for the transfer from the crimping state to the ejection state is in the choice of design engineer. In case of small distances of the edges being of interest in order to avoid fins, ridges or burrs of the surface of the work piece 7 at the end of the crimping process, the protrusions 19, 20 should have a very small extension in the direction of the crimping axis 4 that might lie in the microscopic or macroscopic range. These small protrusions might be built in the front surface of the crimping die halves 2, 3 by a suitable curvature or a fine finishing manufacturing process.

FIGS. 7 and 8 show a free body diagram corresponding to FIGS. 5 and 6. However, according to FIGS. 7 and 8 the crimping die half 2 is shown as a mechanical system module, here a bended beam 30. Due to the ejection forces 27, 28 applied during the spreading movement, the bended beam 30 is subjected to a bending moment acting around an axis having an orientation perpendicular to the drawing plane of FIGS. 5 and 6. As can be seen from FIG. 7, in the shown crimping state, the bended beam 30 is only subjected to the surface pressures given in curves 25, 26 along the width of the crimping contour 5. Laterally from the crimping contour 5, the bended beam 30, i.e., the crimping die half 2, is not subjected to ejection forces due to the distance between the ejection force regions 23, 24 so that there is no significant spreading of the crimping contour 5.

However, in the second region of distances of the crimping die halves, the bending beam 30 is additionally subjected to ejection forces 27, 28 with the result that the beam 30 is subjected to a bending moment, wherein a lever arm of the ejection forces from the crimping axis or the center of the crimping contour 5 corresponds to the distance 29 (see FIG. 8).

FIG. 9 shows the crimping contour 5 in an enlarged view. The crimping contour 5 is shown in a crimping state 31 without a (significant) deformation or spreading effect as well as in the ejection state 32 with the desired deformation or spreading effect. At the end of the main crimping process or at the end of the first region of distances of the crimping die halves the outer contour of the work piece corresponds to the crimping contour 5 in the crimping state 31. When transferring the crimping contour 5 into the ejection state 32 at least in the region of the contour parts 16, a microscopic or macroscopic gap 33 is built in order to ease the removal of the work piece from the crimping contour 5. Due to the spreading movement, the distance 45 or extension of the crimping contour transverse to the crimping axis 4 in the ejection state is smaller than the distance 46 in the ejection state. Furthermore, FIG. 9 shows that an inclination angle of the contour parts 16 with respect to the crimping axis 4 is larger in the ejection state when compared to the crimping state. It is possible that due to the spreading movement, the contour part 5 is elastically deformed into a convex shape.

For building the resilient deformation region 17, the crimping die half according to FIGS. 4 to 6 comprises a recess 34 with a cross-section closed in circumferential direction. The recess 34 has an orientation transverse to the crimping axis 4, transverse to the longitudinal extension of the crimping die half 2 and vertical to the drawing plane according to FIGS. 4 to 6. For a simple embodiment, the recess 34 is a bore of the crimping die half 2. It is also possible that the crimping die half comprises a plurality of recesses 34 with any cross-section.

As can be seen from FIG. 10, the crimping die half might (in an alternative or cumulative embodiment) comprise a recess 35 at the side opposite to the crimping contour. Such recess 35 might have a cross-section, which is open in circumferential direction, e.g. in the shape of a wedge. Also this recess 35 builds a weakening of the crimping die half behind the crimping contour 5 for providing the resilient deformation region 17 and guaranteeing elastic deformations for spreading the crimping contour 5. FIG. 10 also shows the ejection forces 27, 28 acting at the ejection force regions 23, 24. Other ejection forces 36, 37 might be produced by different ejection force regions, e.g. ejection force regions located at the lateral sides of the crimping die half 2 or ejection force regions having an inclination with respect to the crimping axis 4.

For the embodiment shown in FIG. 11, the crimping die half 3 comprises arms 38, 39 laterally passing the front part of the crimping die half 2 and having ejection force regions with contact surfaces being V-shaped. At the end of the main crimping process or at the second region of distances of the crimping die halves, these surfaces of the ejection force regions 40, 41 contact counter-surfaces of ejection force regions 40a, 41a of the other crimping die half 2 causing ejection forces at a position located behind or in front of the crimping contour 5 when seen in the direction of the crimping axis and having an angle of inclination with respect to the crimping axis 4 and a direction transverse to the crimping axis 4. For the embodiment shown in FIG. 11, the ejection force regions are activated by a relative movement of the crimping die halves 2, 3. However, it is also possible that arms 38, 39 or stamps are built separately from the crimping die halves 2, 3. These arms 38, 39 might be moved by a drive of the crimping pliers or the hand levers or are moved separately from the crimping die halves 2, 3. In the embodiment shown in FIG. 11, the arms 38, 39 are moved parallel to the crimping axis 4. In case of the arms 38, 39 or stamps being moved separately from the crimping die halves 2, 3, it is also possible that the arms 38, 39 have an orientation and axis of movement differing from the crimping axis 4. For the embodiment shown in FIG. 10, the movement of the arms 38, 39 has an orientation transverse to the crimping axis 4 for causing ejection forces 36, 37.

FIG. 12 shows another embodiment, wherein the crimping die half comprises both a recess 34 with a closed cross-section as well as a recess 35 having an open cross-section. Furthermore, according to this embodiment a blocking or fixing element 42 is used. The fixing element 42 is located within the recess 35 during the main crimping process or in the first region of distances of the crimping die halves 2, 3, wherein a fixing surface 43 contacts the limiting surfaces of the recess 35. For transferring the crimping contour 5 from the crimping state to the ejection state the fixing element 42 is moved out of contact with the recess 35 such that the spreading movement is initiated with a reduced stiffness. The fixing element 42 is activated by a fixing or locking element 44, wherein the fixing or locking element 44 might be coupled with the drive of the crimping pliers 1 for the crimping process or with a separate drive element that might be manipulated by the user.

FIG. 13 shows a crimping die half 2 having the shape of a half shell, wherein the front ends of the half shell might build the ejection force regions 23, 24. These half-shells might be used for crimping ends of tubes or connecting elements for tubes or fittings.

Many variations and modifications may be made to the preferred embodiments of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of the present invention, as defined by the following claims.

Claims

1. A crimpinq tool with two crimping die halves designed and configured for crimping a work piece in a crimping process, at least one of said crimping die halves comprising

a) a crimping contour having two contour parts,

b) ejection force regions located distant or laterally from said crimping contour,

c) a resilient deformation region, said resilient deformation region ca) connecting said contour parts and cb) determining the distance of said contour parts and/or the angle between said contour parts,

d) a drive mechanism designed and configured for moving said crimping die halves towards each other da) in a first region of distances of said crimping die halves wherein in said first region said crimping die halves crimp the work piece with no substantial forces applied upon the ejection force regions and db) in a second region of distances of said crimping die halves wherein forces are applied upon the ejection force regions, these forces elastically deforming said resilient deformation region and increasing the distance of said contour parts or the angle between said contour parts from a crimping state to an ejection state.

2. The crimpinq tool of claim 1, wherein a cross section of said resilient deformation region taken along a crimping axis comprises a geometrical moment of inertia which is smaller than the geometrical moment of inertia of cross sections of said crimping die half located laterally from said elastic deformation region.

3. The crimpinq tool of claim 2, wherein said crimping die half comprises at least one recess or bore located behind said crimping contour when seen along said crimping axis.

4. The crimping tool of claim 1, wherein at least one of said ejection force regions has a contact surface being slanted with respect to a crimping axis.

5. The crimping tool of claim 1, wherein a fixing element is provided, said fixing element being designed and configured for temporarily blocking the deformation of said resilient deformation region in said crimping state and for fixing the distance of said contour parts or the angle between said contour parts in said crimping state.

6. The crimping tool of claim 3, wherein a fixing element is provided, said fixing element being designed and configured for temporarily blocking the deformation of said resilient deformation region in said crimping state and for fixing the distance of said contour parts or the angle between said contour parts in said crimping state.

7. The crimping tool of claim 6, wherein said fixing element is designed and configured for at least partially filling said recess in said crimping state and for being located without contact to the recess in said ejecting state.

8. The crimping tool of claim 1, wherein said crimping die half comprises a plurality of nests.

9. The crimping tool of claim 1 comprising a spreading element, said spreading element being linked with a manipulation element, wherein with a manipulation of said manipulation element the spreading element, contacts at least one of said crimping die halves for applying a spreading force upon said crimping die half.