Apparatus for connecting a wire to a contact element

In an apparatus for connecting a wire to a contact element by deformation of clamping portions of the contact element by means of pressure members, in particular pressure members of a crimping tool (20) which is arranged interchangeably in an impact press and which has a crimping punch (28) which in a crimping position produces the deformation, for the purposes of producing a plurality of deformation regions on the contact element, a number of crimping punches (28), said number corresponding to the number of the deformation regions, is arranged around a receiving opening, each of which crimping punches can be moved by pressure jaws (46, 47) towards the receiving opening into the crimping position, wherein the pressure jaws (46, 47) are movable by pressure punches (40, 40a) which are provided at an angle with respect thereto. The pressure punches are arranged on both sides of a straight line of symmetry (M) and substantially parallel thereto, with surfaces which are inclined at an angle to the line of symmetry (M) and which engage into the path of movement (44) of inclined surfaces of the pressure jaws (46, 47).

BACKGROUND OF THE INVENTION 
The invention concerns an apparatus for connecting a wire to a contact 
element or the like by deformation of clamping or terminal portions of the 
contact element or the like by means of pressure members, in particular 
pressure members of a crimping tool which is arranged interchangeably in 
an impact press and which has a movable crimping punch or plunger which in 
a crimping position produces the deformation. The invention also concerns 
a connecting process for contact elements. 
Apparatuses of that kind for cable manufacture, for example for fixedly 
connecting wire ends to plugs and cable shoes or connector lugs, usually 
comprise an impact press with a vertically movable pressing punch or 
plunger which acts on a pressure head of the crimping tool which is 
disposed therebeneath, wherein crimping punches or plungers provided in 
the crimping tool are moved downwardly and secure a horizontally inserted 
plug member or the like contact element to the end of a cable or wire, by 
virtue of the deformation of clamping or terminal lugs. The end of the 
cable or wire is stripped of its insulation to a certain length so as to 
provide a diameter which is smaller than the insulated portion. The 
so-called crimping dimension of the punch edge or edges acting on the 
wire, being the dimension that is necessary for the described crimping 
procedure, is adjusted by hand in dependence on the cross-section of the 
wire and the form of the contact element. 
An apparatus of the kind set forth above having a shaping punch or plunger 
or crimper member, by means of which sheet metal lugs are connected to a 
cable by deformation is described in the present applicants' German 
laid-open specification (DE-OS) No. 40 39 051. The edges of the sheet 
metal lugs which are of a U-shape configuration in cross-section are 
rolled in by the crimper member so as to produce a structure which is 
approximately heart-shaped, also in cross-section. 
It is often necessary for a plurality of inwardly directed radial 
deformation portions to be produced in sleeve-like or tubular contacts, 
for which purpose for example star-like wheels on a lever arm are known, 
the wheels rotating about an axis, with a plurality of impact surfaces. 
Such apparatuses are provided with their own drive and are overall of an 
individual configuration, that is to say they are designed specifically 
for a respective contact and are therefore expensive. 
In consideration of that state of the art, the inventor set himself the aim 
of designing an apparatus of the kind set forth in the opening part of 
this specification for producing a plurality of inwardly directed 
deformation portions in a sleeve-like contact element and in the form of a 
quick-change tool for impact presses. The latter can then be used as a 
flexible basic piece of equipment. 
That object is attained by the teaching of the independent claims; the 
appendant claims set forth advantageous developments. 
To produce a plurality of deformation regions on the contact element, a 
number of crimping punches or plungers, said number corresponding to the 
number of deformation regions to be produced, is arranged around a 
receiving opening, which crimping punches can be moved by pressure jaws or 
the like members into the crimping position, wherein the pressure jaws or 
the like members are in turn movable by pressure punches or plungers which 
are provided at an angle with respect thereto. 
For that purpose, it has proven to be desirable to arrange on both sides of 
a straight line of symmetry, pressure punches, which are substantially 
parallel thereto, of the crimping tool, which punches engage into the path 
of movement of inclined surfaces of the pressure jaws, by means of 
surfaces which are inclined at an angle relative to the axis of symmetry. 
In accordance with the invention, for the purposes of return movement of 
the pressure jaw, disposed in opposite relationship to the inclined 
surface or surfaces thereof is a respective parallel inclined surface 
which is associated with a second inclined surface of said pressure punch. 
The co-operating return surfaces of the pressure jaws and the pressure 
punches extend inclinedly relative to the axis of symmetry, in order to 
restore the initial position. 
In accordance with a further feature of the invention the pressure jaw has 
a taper surface which crosses the axis of the associated crimping punch 
and can be pressed against a punch surface which is parallel thereto. In 
accordance with the invention the crimping punch is returned from the 
crimping position by a force-storage means, in particular a compression 
spring. 
It has also been found desirable for the axis of the crimping punch to be 
disposed approximately at a right angle relative to the taper surface 
and/or for the crimping punch to be arranged to be movable against the 
force of a force-storage means into the crimping position. 
Advantageously, both the taper surface and also an oppositely inclined 
oblique groove are formed in a parallelepipedic block of material, wherein 
the inclined groove affords the inclined surfaces for the crimping and 
return movement. 
In accordance with another feature of the invention, engaging into the 
inclined groove in the pressure jaw is a rib which projects from the 
pressure punch in a bar-like configuration and which has said inclined 
surfaces. Those pressure punches which are connected to a rotary head that 
can be raised and lowered can also be produced in a simple manner by a 
cutting machining operation from a block of material. 
The pressure jaw is guided towards the crimping punch against the force of 
a force-storage means which--preferably in the form of a coil 
spring--embraces a securing pin which is connected to the pressure jaw and 
which passes through a fixed guide. 
The above-mentioned guide for the securing pin is a bore in a part of a 
housing in which slide tracks for the pressure jaws extend. Thrust tracks 
for the pressure punches are directed transversely to said slide tracks. 
It is in accordance with the invention for an interchangeable crimping 
insert to be arranged between the thrust tracks and for the crimping 
insert to be provided with guides for the crimping punches. Those guides 
are disposed radially relative to the receiving opening in the crimping 
insert. 
In accordance with the invention, by means of a tool of such a 
configuration, the force of the press is distributed to the pressure 
punches or plungers of the crimping tool and each force portion of the 
crimping punch is converted into at least a force which is at an angle 
relative thereto; that force acts on the crimping punch.

DETAILED DESCRIPTION OF THE DRAWINGS 
An impact press 10 for dealing with wires or cables comprises, beneath a 
press housing 14 which contains control and pressure devices and which is 
disposed on support legs 12 and which has an adjusting plate 16 and 
pressing punch or ram 18, with an operating stroke of 40 mm, a 
quick-change crimping tool 20 with rotary head 22 which is acted upon by 
the pressing punch or ram 18. This unit 10/20 serves for connecting an 
insulated electrical wire to a sleeve-like or tubular contact element 26 
which is separated from a sheet metal strip or line of blanks 24. The 
contact element is pressed or crimped onto the end of the wire, from which 
the insulation has been previously removed, and the adjoining portion of 
the insulation, by deformation; in the crimping operation the sleeve 26 is 
deformed in such a way that for example the flexible conductor wire at the 
end of the wire flows and air pockets or inclusions are obviated. 
As shown in FIG. 3 deformation occurs in four regions A which are 
determined by two cross-sectional straight lines Q1, Q2 which are disposed 
approximately at a right angle to each other. Four crimping punches or 
plungers 28 move in guides 29 in a crimping insert 30 in the crimping tool 
20 in the above-mentioned cross-sectional straight lines Q1, Q2 which 
intersect the central axis M of the tool at the center point Z of the 
tool. The axes Q of the crimping punches 28 therefore coincide with the 
cross-sectional straight lines Q1, Q2. 
As FIG. 4 clearly shows, the crimping insert 30 is interchangeably disposed 
in a housing 32 which is provided with a bottom plate 34, a front plate 35 
of a thickness a1 of 10 mm, side plates 36 and a housing body 37; the 
depth thereof as indicated at a measures 35 mm here, while the diameter d 
of a central bore 33 is about 18 mm. The crimping region B of the crimping 
insert 30 can be seen through an inwardly tapering aperture 31 in the 
front plate 35, the aperture 31 also being central. 
Two pressure punches or plungers 40, 40a engage from above into vertical 
thrust tracks 38 in the housing body 37 and are screwed with their punch 
head surface 39 to a transverse plate 43 of the rotary head 22. The 
transverse plate 43 is at a spacing h relative to the housing 32 (see 
FIGS. 4 and 7) in the upper dead center position of the press 10. When the 
press 10 is in its lower dead center position, the transverse plate 43 
extends near the housing body 37 as shown in FIGS. 6 and 8. 
Extending transversely to the center line M of the tool, in the housing 32, 
are horizontal slide tracks 44 for upper pressure jaws 46 and lower 
pressure jaws 47, which coincide with the axes of securing pins 48. The 
latter each pass through a respective bore 36a in a side plate 36 and are 
embraced by a spring 49 which bears against the side plate 36 and the pin 
head 48a. 
Different positions of the pins 48 which are fixed with their shank to the 
pressure jaws 46, 47 are indicated at top right in FIGS. 7 and 8. If the 
pressure jaw 46, 47 were not secured by the securing pin 48 and the spring 
49 it could move in its basic position on the horizontal axis and thus 
damage the tool in the working stroke movement; the spring 49 holds the 
pressure jaw 46, 47 in position. 
The movements of the tool portions during the shaping operation and the 
forces involved therein are indicated by arrows in FIG. 6, with the 
following meanings: 
F.sub.1 =vertical pressing stroke movement; 
F.sub.2 =transmission of F.sub.1 in the form of a longitudinal stroke 
movement to the pressing punches 40, 40a of the crimping tool 20; 
F.sub.3 =transmission of the longitudinal stroke movement F.sub.2 for the 
transverse stroke movement of the pressure jaws 46, 47; and 
F.sub.4 =transmission of the transverse stroke movement F.sub.3 in the form 
of a diagonal stroke movement for the crimping punches 28. 
A wedge or taper system which is described hereinafter is used to perform 
that sequence of stroke movements. 
The pressing stroke movement which is transmitted from the press 10 to the 
rotary head 22 permits individual tool setting; the force F1 is 
distributed by way of the transverse plate 42 to the left-hand and 
right-hand pressure punches or plungers 40, 40a--each of a width b of 19 
mm but with different lengths as indicated at n, n1 of 94 mm for the 
left-hand pressure punch 40 and 100 mm for the right-hand pressure punch 
40a. The stroke movement of 40 mm of the press 10 is directly transmitted 
to the two pressure punches so that they are also capable of performing a 
stroke movement of that order of magnitude. 
The pressure punches 40, 40a are each provided with two inclined pressure 
surfaces 50 which are presented at an angle w of about 15.degree. as side 
surfaces of ribs 52 and which project by a dimension e of 3 mm here beyond 
a first front surface 41 of the pressure punch 40, the depth b1 of which 
is about 15 mm. Towards the crimping insert 30, a transversely extending 
shoulder step 42s is formed between the first or outer front surface 41 
and a second --inner--front surface 42. The mutually facing end faces of 
the ribs 52 are identified by reference 53 and the upper rib 52 is of a 
configuration like a "7" in front view; the end of the transverse bar 
portion of the upper rib 52, that transverse bar portion extending at the 
punch head surface 39, is indicated at 54. The base surface 55 of the 
lower rib 50 which forms a straight line is disposed at a spacing z 
relative to the lower punch surface 39t; it is shorter in the case of the 
left-hand pressure punch 40 than in the case of the other. 
If the pressure punch 40--and equally the other pressure punch 40a--moves 
downwardly on the other side of the axis of symmetry M, the vertically 
moved inclined pressure surfaces 50 as well as the parallel inclined back 
surfaces 56 of the ribs 52, which are each provided on the other side of 
the respective rib, exactly co-operate with corresponding inclined 
surfaces 58 and back surfaces 60 respectively of the horizontally guided 
pressure jaws 46, 47. In that situation the vertical force F2 produces the 
horizontal force F3 and the longitudinal movement turns into a transverse 
movement. 
The pressure punches 40, 40a and the pressure jaws 46, 47 have a positive 
pull-back action so that, upon retraction of the press 10, the pressure 
jaws 46, 47 which are guided in the slide tracks 44 are pulled back into 
the basic position shown in FIG. 7. 
As shown in particular in FIG. 15, provided in the pressure jaw 47, in this 
case the lower right pressure jaw, which is made from a workpiece 
parallelepiped, is a lateral cut-out or recess 62 of a depth f of 7 mm 
here, from the inside surface of which an inclined groove 64 of a width g 
of 5 mm extends at an angle of inclination t in the pressing direction x 
of about 75.degree., the side walls thereof being the above-mentioned 
inclined surface 58 and the back surface 60. FIG. 15 also shows in the end 
surface 61 of the parallelepiped a bore 61a for receiving the 
above-mentioned securing pin 48. 
Disposed adjacent the inclined surface 58 at the other side wall of the 
pressure jaw 47 is an oppositely extending upwardly directed wedge or 
taper surface 66 at an angle i of 45.degree.. 
In the embodiment shown in FIGS. 18 and 19 of the top left pressure jaw 46, 
the surfaces 58, 60 and 66 are inclined to the same extent, but here the 
wedge or taper surface 66 faces downwardly. 
The dimension of the transverse stroke movement F3 produced upon actuation 
of the pressure jaws 46, 47 is identified by k. The lower left pressure 
jaw 47 is emphasised by hatching in FIGS. 7 and 8 for the sake of enhanced 
clarity thereof. 
Various crimping inserts 30 with the crimping punches 28 diagrammatically 
shown in FIG. 6 can now be mounted in the crimping tool 20; in the 
transverse stroke movement x of the pressure jaws 46, 47, they are urged 
by the taper surface 66 towards the center Z; F3 is converted into F4. 
The return of the crimping punches 28 is effected by springs (not shown) as 
soon as the taper surfaces 66 have disengaged the end surfaces 29 of the 
crimping punches 28. When the crimping punches 28 move apart, the feed 
opening defined by the tips 27 thereof is enlarged.