Abstract
The inventions relates to crimping pliers with two hand levers (3, 5) and two actuation elements (9, 10) located in the region of a pliers head (4). The actuation elements (9, 10) actuates dies (12) between which a workpiece can be crimped. A toggle lever drive (33) with two toggle levers (34, 35) which build a toggle lever angle (36) acts between the hand levers (3, 5) and the actuation elements (9, 10). One toggle lever (34) is built by a roller (23) which is pivotably mounted to the hand lever (5). The roller (23) rolls along a curved track (24) fixed at the other hand lever (3). A forced locking unit (48) is built with a toothed latching lever (28) which is supported for being rotated relatively to the roller (23). A lever part (30) of the toothed latching lever (28) is coupled by a sliding guide to the hand lever (3), whereas the other lever part (29) of the toothed latching lever (28) forms a toothing (31) for latching of the forced locking unit (48).
Claims
1. Crimping pliers for crimping a workpiece comprising a) two drive elements, b) a pliers head connected to the two drive elements and comprising, ba) two actuation elements, the actuation elements linked to and actuating dies between which the workpiece can be crimped, c) a toggle lever drive linked to both the drive elements and the actuation elements, ca) wherein the toggle lever drive comprises two toggle levers, cb) wherein the toggle levers are connected at a toggle lever angle which changes over a working stroke, d) wherein one toggle lever comprises a roller having a roller axis which da) is mounted to a first one of the drive elements for being pivoted around said roller axis and eb) rolls along a curved track, said curved track being fixedly connected to the second drive element, e) a forced locking unit comprising a toothed latching lever, said toothed latching lever being mounted to the first drive element and pivots with respect to both ea) the first drive element and eb) the roller, wherein the toothed latching lever is mounted to the first drive element and forms a pivot joint with respect to the first drive element, wherein the toothed latching lever, the drive element at which the roller is pivot mounted and the rollers are pivoted relative to each other, f) a sliding guide wherein a first lever part of the toothed latching lever is coupled by said sliding guide with the second drive element and g) a second lever part of the toothed latching lever forms a toothing comprising teeth for latching of the forced locking unit.
2. The crimping pliers of claim 1, wherein the toothed latching lever is rotatably mounted about the roller axis at the first drive element.
3. The crimping pliers of claim 2, wherein the roller and the toothed latching lever are supported on a common bearing bolt.
4. The crimping pliers of claim 1, wherein the sliding guide comprises an elongated hole.
5. The crimping pliers of claim 4, wherein a bearing bolt a) guides the toothed latching lever in the elongated hole and b) fixes a guiding part forming the curved track.
6. The crimping pliers of claim 1 further comprising, a force-displacement-compensation element comprising a spring element.
7. The crimping pliers of claim 6, wherein the spring element is guided by a guide.
8. The crimping pliers of claim 7, wherein the spring element comprises a bending beam.
9. The crimping pliers of claim 8, wherein the spring element comprises a plate-design with at least two plates.
10. The crimping pliers of claim 8, wherein the spring element comprises a spring having the shape of an arc of a circle or comprises a spiral spring.
11. The crimping pliers of claim 9, wherein the spring element comprises a spring having the shape of an arc of a circle or comprises a spiral spring.
12. The crimping pliers of claim 1, wherein a) a first one of the actuation elements comprises guidances for dies and b) a second one of the actuation elements comprises actuation surfaces for the dies, c) wherein a relative movement of the actuation elements causes a movement of the dies relative to the guidances which is caused by the contact of the actuation surfaces with the dies.
13. The crimping pliers of claim 12, wherein a) the actuation elements are pivoted relative to each other about the pivot axis, b) the dies are mounted for being pivoted relative to the guidances and c) the relative pivoting movement of the actuation elements causes a pivoting movement of the dies relative to the guidances which is caused by the contact of the actuation surfaces with the dies.
14. The crimping pliers of claim 1, wherein by use of a) a force-displacement-compensation provided by a force-displacement-compensation element and/or b) a movement of the roller along the curved track with a change of a size and angular conditions of the toggle lever drive crimp workpieces with differing cross-sectional areas to be crimped, wherein for two different workpieces crimped with the crimping pliers the cross-sectional areas differ by at least a factor 30.
15. The crimping pliers of claim 1, wherein the pliers head further comprises a positioning device for at least one workpiece.
16. The crimping pliers of claim 6, wherein the spring element comprises a bending beam.
17. The crimping pliers of claim 16, wherein the spring element comprises a plate-design with at least two plates.
18. The crimping pliers of claim 17, wherein the spring element comprises a spring having the shape of an arc of a circle or by a spiral spring.
19. The crimping pliers of claim 17, wherein the spring element comprises a spring having the shape of an arc of a circle or by a spiral spring.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) 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.
(2) FIGS. 1 to 11 show a first embodiment of the crimping pliers in an open position (FIG. 1), a closed position (FIG. 2), with components of the crimping pliers in an exploded view (FIGS. 3 and 4), with a guiding part with curved tracks in a three-dimensional single part drawing (FIG. 5), with a toggle lever angle of the crimping pliers in the open position (FIG. 6) and in the closed position (FIG. 7) and with the actuating force curves for different workpieces (FIG. 8) and with the dimensions of the spring element (FIGS. 9 and 10) and with the resulting curves for the tension in the spring element (FIG. 11).
(3) FIG. 12 shows another embodiment of the crimping pliers.
(4) FIGS. 13 to 14 show another embodiment of the crimping pliers with an additional guidance of the spring element.
DETAILED DESCRIPTION
(5) FIG. 1 shows crimping pliers 1 in an illustration wherein one of two cover plates 2a, 2b with which a fixed hand lever 3 and a pliers head 4, in particular in a kind of housing of the pliers head 4, is built, is disassembled.
(6) The crimping pliers 1 are built with a fixed hand lever 3 and a movable hand lever 5. A pivoting of the hand levers 3, 5 towards each other (cp. the transition from FIG. 1 to FIG. 2) via a drive mechanism 6 and a spring element 7, which builds a force-displacement-compensation element 8 generates a relative movement of actuation elements 9, 10. Here, the actuation element 9 is integrally built by the part of the cover plate 2 which extends in the region of the pliers head 4 so that a fixed actuation element 9 is built. Instead, the actuation element 10 is a movable actuation element 10 in the form of a pivot ring 11 which can be pivoted relative to the fixed actuation element 9 about a workpiece axis or die axis 13 defined by dies 12. Here the die axis 13 has an orientation perpendicular to the plane of illustration according to FIG. 1. The dies 12 are pivotable about axes which have an orientation parallel to the die axis 13 and which are supported by bearing bolts 14 which are held at the actuation element 9 or the cover plate 2. The bearing bolts 14 accordingly build guidances 15 for the dies 12. At the radial inner side in the region of grooves the pivot ring 11 forms actuation surfaces 16 at which counter-actuation surfaces 17 of the dies 12 contact so that a pivoting of the pivot ring 11 about the pivot axis 13 results in a pivoting movement of the dies 12 around the bearing bolts 14. The pivoting movement of the dies 12 again has the consequence that a die contour 18 changes its size. Here, the die contour is defined by the dies 12 and closed in circumferential direction around the die axis 13 under the build-up of a minimal gap between the adjacent dies 12. For the shown embodiment the die contour 18 is hexagonal in a first approximation independent from the size of the same.
(7) The spring element 7 is built by an integral protrusion of the pivot ring 11 which extends in circumferential direction around the pivot axis 13 with the shape of an arc of a circle or here a spiral form. For the shown embodiment the circumferential angle is approximately 360. The spring base 19 building the connecting region with the pivot ring 11 as well as the outer spring base 20 of the spring element 7 are approximately located in a 4o'clock position with respect to the die axis 13 for the illustration according to FIG. 1 wherein the fixed hand lever 3 has a horizontal orientation. The spring base 20 is pivotably liked, here by a bearing bolt 21 at the movable hand lever 5. A roller 23 is supported for being rotated at the movable hand lever 5, here by a bearing bolt 22. The roller 23 contacts a curved track 24 of a guiding part 25. In the present case, by the curved track 24 the guiding part 25 only guides the roller 23 on one side. However, for another embodiment it is also possible that the roller 23 is accommodated between two curved tracks which might be the case with some play or without any play. The guiding part 25 is rigidly fixed to the fixed hand lever 3, here by bearing bolts 26, 27. By the bearing bolt 22 also a toothed latching lever 28 is supported for being pivoted. The toothed latching lever 28 is built with lever parts 29, 30. In the outer end region the lever part 29 forms a toothing 31 for latching. The lever part 30 comprises an elongated hole 32 having an orientation radially to the bearing bolt 22. The bearing bolt 27 extends through the elongated hole 32.
(8) The drive mechanism 6 is formed by a toggle lever drive 33. The toggle lever drive 33 comprises a toggle lever 34 which corresponds to the connection between the contact point of the roller 23 with the curved track 24 and a second toggle lever 35 which corresponds to the connection between the bearing axes defined by the bearing bolts 21, 22. A toggle lever angle 36 is built between the toggle levers 34, 35.
(9) During the working stroke of the crimping pliers 1 from the open position according to FIG. 1 to the closed position according to FIG. 2, the movement of the hand levers 3, 5 in a first part of the stroke with neglectable crimping forces and with a support of the roller 23 at the curved track 24 of the guiding part 25 leads to the result that the bearing bolt 21 and therewith also the spring base 20 of the spring element 7 move in circumferential direction 37 around the die axis 13. Due to the neglectable crimping forces, there is no elastic deformation of the spring element 7. Accordingly, there is a corresponding pivoting movement of the pivot ring 19 which again coincides with a pivoting movement of the dies 12 and a reduction of the cross-sectional area of the die contour 18. Due to the fact that the contact point of the roller 13 with the curved track 24 of the guiding part 25 is not fixed, the roller 23 is able to roll along the curved track 24 during this part of the stroke. Dependent on the rolling movement of the roller 23 and on the geometry of the curved track 24, a changed toggle lever angle 36 results. This complex kinematic is superimposed by an increased elastic deformation of the spring element 7 with an increase of the crimping forces in the region of the die during closing movement. This shall be illustrated on the basis of a theoretical limit case for which it is assumed that the workpiece after a first part of the stroke (which might e.g. be formed by an empty stroke) and after a second part of the stroke (by which the workpiece is crimped with a plastic deformation of the same) the workpiece is ideally rigid in the last third part of the stroke. When reaching the ideally rigid state of the workpiece, the position of the dies 12 and the pivot ring 11 and accordingly also of the spring base 19 is also fixed. However, a further closing movement of the hand levers 3, 5 is possible in the third part of the stroke because with the further actuation of the hand levers 3, 5 the spring element 7 is elastically deformed. On the one hand side, the spring base 20 is deformed in circumferential direction 37. It is also possible that the spring base 20 is deformed in radial direction 38 of the die axis 13. Accordingly, despite of the rigid workpiece and fixed dies 12, fixed pivot ring 11 and fixed spring base 19, a rolling movement of the roller 23 along the curved track 24 takes place with the transfer of the hand levers 3, 5 into the closed state. For realistic stiffnesses of the workpiece there is a superposition of a plastic deformation of the workpiece (which becomes smaller with increasing crimping force) with an elastic deformation of the spring element 7, wherein the percentage of the elastic deformation of the spring element 7 relative to the plastic deformation of the workpiece becomes larger and larger with increasing crimping force. Accordingly, in practice in some cases there is a superposition of the second part of the stroke and the third part of the stroke.
(10) Dependent on the cross-sectional area of the workpiece to be crimped, the position of the different parts of the stroke over the working stroke of the crimping pliers 1 changes: For a large workpiece an empty stroke building the first part of the stroke (e.g. between 0% and 15% of the working stroke) is very short. A plastic deformation of the workpiece takes place in a second part of the stroke, e.g. already at the beginning of the working stroke (e.g. between 15% and 60% of the working stroke), whereas a larger third part of the stroke (e.g. between 60% and 100% of the working stroke) follows in which primarily the spring element 7 is deformed. For a smaller workpiece an empty stroke building the first part of the stroke (e.g. between 0% and 30% of the working stroke) is longer. A plastic deformation of the workpiece follows in a second part of the stroke in a later part of the working stroke (e.g. between 30% and 80% of the working stroke), whereas a smaller third part of the stroke (e.g. between 80% and 100% of the working stroke) or even no third part of the stroke follows wherein primarily the spring element 7 is deformed.
(11) At the same time with the pivoting movement of the hand levers 3, 5 towards each other, the toothed latching lever 28 is pivoted. During the pivoting movement of the toothed latching lever 28 a latching nose 39 of a latching pawl 40 which is also mounted for a pivoting movement at the hand lever 5 under the bias of a spring 93 slides ratchet-like along the toothing 31 for latching. If the hand forces applied to the hand levers 3, 5 are temporarily reduced or completely removed, the engagement of the latching nose 39 into the toothing 31 for latching blocks the opening movement of the hand levers 3, 5 and therewith also an opening movement of the dies 12. Only if the hand levers 3, 5 have completely reached the closed state, the latching nose 39 has completely passed the toothing 31 for latching so that the latching pawl 40 is able to turn over and to slide in a ratchet-like fashion during an opening movement of the hand levers 3, 5 back into its starting position (which by use of the toothing 31 for latching is only possible when having completely passed the toothing 31 for latching). A forced locking unit 48 is built with the toothed latching lever 28 and the latching pawl 40 biased by the spring 39.
(12) For the general design of crimping pliers 1 with a pivot ring 11 and the provision of a common pivoting movement of here six dies 12 by a relative rotation of the actuation elements 9, 10, reference is made to the prior art, in particular EP 0 732 779 B1 and DE 10 140 270 B4 and DE 10 2005 003 615 B3. In the present case, the hand levers 3, 5 build drive elements 41, 42 upon which the manual actuation forces are applied. It will be understood that it is also possible that the drive elements 41, 42 are biased by forces of an actuator as an electrical drive.
(13) Here, the spring element 7 is built by a type of bending beam 43. In the region of the spring base 20 force components in circumferential direction 37 and/or in radial direction 38 are introduced into the bending beam 43. These force components result in the bias of the bending beam 43 around a bending axis which has an orientation perpendicular to the plane of illustration according to FIG. 1. Here, generally also the use of a bias of the bending beam 43 by a pressing force resulting in a buckling is possible. However, preferably the bending beam 43 is biased by a pulling force in circumferential direction 37. For the shown embodiment the bending beam 43 is built by a spiral spring or a spring 44 having the shape of an arc of a circle extending in the plane of illustration according to FIG. 1. Here, the spiral spring or spring with the shape of an arc of a circle extends in circumferential direction 37 around the die axis 13.
(14) The bending beam 43 comprises a neutral fiber or longitudinal axis 45 which here has the shape of an arc of a circle or a spiral shape. The bending stiffness changes along the neutral fiber or longitudinal axis 45, in particular due to a change of the geometric moment of inertia. For the shown embodiment the design of the size of the cross-section of the bending beam 43 which determines the geometric moment of inertia is symmetrical to a symmetry axis which runs through the die axis 13 and the spring base 20. In the same way the heights and the cross-sectional area of the spring element 7 is maximal in a cross-section 47 which is located in the middle in circumferential direction between the spring bases 19, 20.
(15) In the explodes view of FIG. 3 it can be seen that the crimping pliers are built with two cover plates 2a, 2b. The two cover plates 2a, 2b build the fixed hand lever 3. On the other hand, the cover plates 2a, 2b build a kind of housing of the pliers head 4. Between the cover plates 2a, 2b the movable parts, namely the spring element 7, the pivot ring 11 and the dies 12 are accommodated. On the other hand, the bearing bolts 14 for the dies 12 are accommodated in bores 49 of the cover plates 2a, 2b.
(16) Furthermore, in FIG. 3 it can be seen that the spring element 7 and the pivot ring 11 are formed by a plate design, here with four plates. The single plates for the pivot ring 11 and the spring element 7 are built as integral parts.
(17) Differing from the embodiment shown in FIGS. 1 and 2, according to FIG. 3 the spring element optionally comprises a protrusion 50 at its outer side. A spring base 51 or a plug or stem coupled with any such spring base of another spring 52 is supported at the protrusion 52. The other spring base 53 of the other spring 52 is supported at the cover plates 2a, 2b or at the movable hand lever 5. By the other spring 52 it is possible to influence the force conditions at the crimping pliers 1 additionally to the spring element 7. Accordingly, the other spring 52 can be used for manipulating the dependency of the produced crimping force from the pivot angles of the hand levers and from the actuating force applied to the hand levers. It is also possible that by the other spring 52 the contact force of the roller 23 with the curved track 24 of the guiding part 25 is increased or provided.
(18) FIG. 4 shows the assembled basic components of the crimping pliers 1 according to FIG. 3 before being assembled with handles 54, 55 associated with the two hand levers 3, 5.
(19) According to FIGS. 3 and 4, it is possible that the crimping pliers 1 comprises a positioning device 56. For the shown embodiment the positioning device 56 comprises three alternative accommodations 57a, 57b, 57c for workpieces with differing cross-sectional areas. The positioning device 56 can be brought into different operating positions in which a respective one of the accommodations 57a (57b, 57c ) is arranged with an orientation coaxial to the die axis. 13. For the shown embodiment the positioning device 65 is built with a positioning strut or a positioning disc 58 which is supported for being pivoted at the cover plates 2, here by a bearing bolt 50. The positioning strut or positioning disc 58 directly and slidingly contacts the outer side of the cover plate 2b.
(20) As shown in FIG. 5, the guiding part 25 has a fork-like shape with the formation of a slit 60 between two legs 61a, 61b. Under the provision of a relative pivoting movement the toothed latching lever 28 extends through the slit 60 of the guiding part 25 (cp. also FIG. 3). In the outer end region the legs 61a, 61b each have a bore 62a, 62b through which the bearing bolts 27 extend in the assembled state. For weight reasons the legs 61a, 61b might comprise recesses 63.
(21) In FIG. 5 it can be seen that for the shown embodiment the two legs 61a, 61b form two parallel curved tracks 24a, 24b at which the two roller 23a, 23b on both sides of the toothed latching lever 28 roll along. Furthermore, it can be seen that for the shown embodiment the curved tracks 24a, 24b comprise two concave partial regions 64, 65 between which a convex partial region 66 is located. Here, the curved track 24 has a larger inclination in the concave partial region 65 which is run through at the beginning of the working stroke than in the other partial regions of the curved track 24.
(22) By a choice of a suitable shape of the curved track 24 it can be provided that the toggle lever angle 36 of the toggle lever drive 33 is comparatively large during the whole working stroke. According to FIG. 6, at the beginning of the working stroke the toggle lever angle 36 is approximately 135, whereas the toggle lever angle 36 is in the range between 160 to 180 at the end of the working stroke according to FIG. 7. Preferably, the toggle lever angle 36 is during the whole working stroke always between 130 and the stretched angle of 180 which is due to a suitable shape of the curved track 24, a choice of the characteristic and geometry of the spring element as well as the dimensioning of the drive mechanism 6.
(23) FIG. 8 shows the hand forces 67 being required as a function of the actuation displacement 68 of the movable hand lever 5. Here, the curves 69 to 81 show the curves for the hand force for differing cross-sectional areas of the workpieces, namely 0.08 mm.sup.2 (69), 0.14 mm.sup.2 (70), 0.25 mm.sup.2 (71), 0.35 mm.sup.2 (72), 0.5 mm.sup.2 (73), 0.75 mm.sup.2 (74), 1.0 mm.sup.2 (75), 1.5 mm.sup.2 (76) 2.5 mm.sup.2 (77), 4 mm.sup.2 (78), 6 mm.sup.2 (79), 10 mm.sup.2 (80) and 16 mm (81). Here it can be seen that for smaller workpieces at first the starting first part of the stroke is run through with neglectable crimping forces, whereas the actual hand forces are only applied at the end of the working stroke. With increasing size of the workpiece the rising of the curves 69 to 81 is shifted towards smaller actuating displacements. In FIG. 8 it can be seen that a crimping of all of the mentioned workpieces is possible with one and the same crimping pliers 1 by controllable hand forces which are preferably smaller than 300 N.
(24) FIG. 9 shows an example for the choice of the dimensions of the spring element 7. It can be seen that the spring element spirally extends around the die axis 13 with an angle in circumferential direction of approximately 360. The effective height 82 of the spring element 7 for influencing the geometric moment of inertia is symmetrical to the symmetry axis 46 or increases from both spring bases 19, 29 in the same extent to the middle of the spring element 7 in circumferential direction between the two spring bases 19, 20. Whereas in FIG. 9 only discrete values of the heights 82 of the spring element 7 are given, FIG. 10 shows the dependency of the heights 82 from the circumferential angle 83 starting from the location in the middle between the two spring bases 19, 20.
(25) FIG. 11 shows the distribution of the tension in the spring element 7, wherein here for the same tension the same grey scale has been used. By means of the symmetric design of the spring element 7 and the choice of the heights 82 according to FIG. 10, it can be provided that the maximum of the tension in the spring element 7 remains constant along the circumference or along the longitudinal axis 45.
(26) FIG. 12 shows another embodiment of the crimping pliers 1 which generally corresponds to the embodiment shown in FIGS. 1 to 11. However, here the contour of the curved track 24 has been chosen such that the contour only comprises concave partial regions 64, 65 which are connected with each other by a straight partial region 89.
(27) FIGS. 13 and 14 show another embodiment of crimping pliers, wherein FIG. 13 shows the crimping pliers in the open position with assembled cover plate and FIG. 14 shows the crimping pliers also in the open position but with disassembled cover plate. This embodiment generally corresponds to the embodiment of the crimping pliers 1 according to FIGS. 1 to 11 or FIG. 12. However, here the spring element 7 is guided in an additional guidance 90. For the shown embodiment, the guidance is provided in the region of the spring base 20. The guidance 90 is built by a guiding pin 91 held by the spring element 7. The guiding pin 91 is guided in a guiding groove or an elongated hole 92 of the cover plates 2. Preferably, the elongated hole 92 extends in circumferential direction around the pivot axis 13.
(28) For the shown embodiment the guiding part 25 is mounted to the fixed hand lever 3, whereas the roller 23 is mounted for being pivoted at the movable hand lever 5. However, it is also possible that the guiding part 25 is fixedly mounted to the movable hand lever 5, whereas the roller 23 is mounted for being rotated at the fixed hand lever 3.
(29) It is possible that within the frame of the invention the same base construction is used for crimping pliers actuated by hand and for crimping pliers actuated by an external force. However, in this case hand levers are used as the drive elements for the manually actuated crimping pliers, whereas for the crimping pliers actuated by an external force instead of the hand levers drive elements linked with an actuator will be used. To mention a simple non-limiting example, for crimping pliers actuated by an external force it is also possible that the fixed (hand) lever is shortened and supported at a fixed counter bearing, whereas a crank plug, a stem or plug or the like of an actuator is linked to the movable (in some cases also shortened) (hand) lever. In some cases crimping pliers being actuated by an external force do not comprise a forced locking unit.
(30) 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.
