Crimper for crimping cable terminals, cable connectors, and similar materials to electric conductors, optical conductors, etc.

A crimper for crimping cable terminals, cable connectors, and similar materials to electric conductors, optical conductors, etc. has two handles (2 & 7) that can be displaced toward each other and two crimping jaws (3 & 5), whereby one crimping jaw (5) is mounted so that it can move on the other (3). The moving handle (7) is mounted on an articulated support (19) on the moving crimping jaw (5). A toggle-lever drive mechanism consists of a pressure-application arm (8) and of a toggle-lever section (18) on the moving handle, whereby the ratio between lengths is at least approximately 2:1. The closing motion of the toggle-lever drive mechanism is terminated just before the extended state is attained by stops (24 & 25). At least one articulated support (19 or 20) can be displaced to vary the pressure. There is an automatic locking mechanism with a resiliently movable but stationary latch (11) that prevents the crimper from opening before crimping jaws have closed. The latch is mounted on the pressure-application arm and the automatic locking mechanism has a toothed section (14) with a number of teeth (22) rigidly fastened to the moving handle.

A crimper of this type is known from German AS No. 2 521 378. It is 
important to note that the crimper has a high transmission ratio. A 
toggle-lever drive mechanism consisting of a pressure-application arm and 
of one component of a moving handle that constitutes a toggle-lever 
section is employed. The toggle-lever section and the pressure-application 
arm are connected by means of a toggle. The moving handle engages a moving 
crimping jaw through an articulated support. The articulated support and 
the toggle more or less merge into the design of the moving handle. The 
pressure-application arm is at least twice as long as the toggle-lever 
section of the moving handle. The second transmission is dictated by how 
far the articulated support on the moving crimping jaw is from its pivot 
in relation to how far a crimping contour is from that pivot. The second 
transmission is approximately 1:1. The pressure-application arm of the 
toggle-lever drive mechanism is mounted on an articulated support on a 
stationary handle, a support that can be displaced to vary the pressure 
when the crimping jaws are closed. The toggle-lever drive mechanism is 
only exploited until just up to the extended state, meaning that the 
extended state is avoided by means of a stop, so that the crimper will 
open again only due to the force of a spring once a pressure-application 
procedure has been carried out. Pressure is easy to apply by hand due to 
the high transmission ratio. An automatic locking mechanism is provided to 
prevent the application of pressure from being prematurely discontinued. 
The locking mechanism has two teeth on the moving crimping jaw that 
operate in conjunction with a resiliently mounted latch on the stationary 
handle. Since the automatic locking mechanism is accordingly positioned in 
the vicinity of the articulation that the moving crimping jaw pivots 
around in relation to the stationary component of the crimper, the paths 
or angle that occur when the crimper closes are very small, so that not 
only the position of the two teeth but also the mounting and design of the 
latch must be established very precisely during manufacture if the 
automatic locking mechanism is to ensure a perfect closure that can be 
reproduced over a large number of crimpers. This, however, is in itself 
actually the purpose of such an automatic locking mechanism--to ensure 
that the pressure is completely applied and not discontinued prematurely, 
so that the crimping would not be carried out with the desired pressure 
and the desired level of pressure. The short strokes also make it possible 
to accommodate only two teeth on the moving crimping jaw. Since these two 
teeth only engage the resilient latch toward the end of the closing 
motion, it is still possible for the application of pressure to be 
discontinued very early and while still incomplete, before the automatic 
locking mechanism has engaged. Still, there is an advantage to the known 
automatic locking mechanism in that the articulated support for the 
pressure-application arm on the stationary handle can be displaced to vary 
the pressure in the closed state without simultaneously adjusting the 
angle at which the locking mechanism is engaged or disengaged. 
German GM No. 7 205 611 discloses a crimper that features in addition to 
the stationary crimping jaw a crimping jaw that moves in a straight line. 
This crimper utilizes a toggle-lever drive mechanism consisting of a 
toggle-lever section on the moving handle and of a tie rod that leads to 
the crimping jaw. The ratio of the lengths of these components is 
approximately 1:1. There is a stop that prevents the toggle-lever drive 
mechanism from becoming fully extended. Thus, the crimper opens 
automatically subject to the force of a spring once the pressure has been 
applied. This design, although somewhat different, also involves an 
automatic locking mechanism that consists of three teeth mounted on the 
moving handle and of a resiliently mounted latch mounted on the stationary 
component of the crimper. The crimper also entails the drawback that, due 
to the short strokes that must be traveled along the automatic locking 
mechanism, the teeth and the latch must be positioned very precisely in 
order to establish the point or angle of opening at an operating point on 
the toggle lever in such a way that the identical operating point can be 
reproduced when the crimper is manufactured on an industrial scale. 
A different type of crimper is known from German Patent No. 27 2 555 071. 
Although this crimper does have both a stationary and a pivoting crimping 
jaw as well as a stationary handle and a handle that is articulated to the 
moving crimping jaw and involves a toggle-lever section, the 
pressure-application arm, which is part of the toggle-lever drive 
mechanism, is approximately as long as the toggle-lever section, and the 
articulated support for the pressure-application arm is located 
approximately at the midpoint of the stationary handle. Since the moving 
handle travels very far when the crimper opens, the tool is very difficult 
to operate with one hand. The pressure that can be applied in this way is 
comparatively weak. An arm with a toothed section either extends parallel 
to the pressure-application arm or is integrated into it between the 
articulated support on the stationary handle and the toggle on the moving 
handle. There is a latch on the moving handle that constitutes in 
conjunction with the toothed section an automatic locking mechanism. The 
toothed section can in a practical way be long enough to engage over 
almost the total range of the closing motion. The articulated support for 
the pressure-application arm and the toothed arm can be displaced, 
specifically by means of an eccentric, to vary the pressure. When the 
eccentric acts only on the toothed arm and not on the pressure-application 
arm, it is only the effective angle of the toggle lever that is affected, 
and the pressure is not necessarily varied simultaneously. In the opposite 
situation, when the eccentric adjusts only the pressure-application arm 
and not the toothed arm, it is of course possible to adjust the pressure 
without necessarily adjusting the effective angle of the toggle lever as 
well. Still, a prerequisite is the separation of the two arms, of the 
pressure-application arm on the one hand and of the toothed arm on the 
other. When the two arms are integrated into one component and the 
adjustment is to occur in relation to the articulated support, with the 
effective length of the pressure-application arm being varied, German 
Patent No. 2 555 071 says that the adjustment of the pressure is 
necessarily relation to the adjustment of the effective angle of the 
toggle lever. Finally, the potential is also disclosed of employing a 
pressure-application arm with a separate moving toothed arm to adjust both 
the articulated support on the stationary component of the crimper and, in 
the opposite direction, the toggle-lever articulation in order to prevent, 
through the second means of adjustment, automatic de-adjustment of the 
effective toggle-lever angle. This is, however, very complicated and 
scarcely practical. 
The object of the present invention is to improve a crimper of the 
aforesaid type to the extent that adjustments for varying the pressure 
will be simple without simultaneously adjusting the point or angle that 
the automatic locking mechanism opens at. The crimping jaws should also 
always close at the same effective toggle-lever angle even at various 
pressures. Furthermore, the automatic locking mechanism should operate 
over the longest possible closure stroke. 
This object is attained in accordance with the invention in that the latch 
for the automatic locking mechanism is positioned on the 
pressure-application arm and in that the automatic locking mechanism has a 
toothed section with a number of teeth positioned stationary on the moving 
handle. The invention derives from the awareness that the point or angle 
that the automatic locking mechanism opens at will be constant when the 
toggle-lever drive mechanism consists only of the pressure-application arm 
and of the toggle-lever section on the moving handle and when the toothed 
section is rigidly connected to one of the two components and the 
resilient latch to the other. Varying the length of the 
pressure-application arm or of the toggle-lever section in order to adjust 
the pressure will accordingly not lead in this design to automatic 
adjustment of the effective toggle-lever angle, which remain constant. The 
toothed section is positioned on the moving handle for reasons of design 
and of manufacturing technology. Still, the opposite arrangement of the 
components of the automatic arm-locking mechanism would basically also be 
possible. The automatic locking mechanism is positioned at the aforesaid 
point at a location on the crimper where on the one hand it can easily be 
accommodated and on the other will travel greater strokes due to the 
transmission than would be possible in the vicinity of the crimping jaws. 
Thus, only normal manufacturing precision will be adequate to ensure 
reproducibility of the effective toggle-lever angle in industrial-scale 
manufacture. It is no longer necessary as at state of the art to provide a 
separate toothed arm in addition to the pressure-application arm or to 
undertake adjustment in two stages to prevent automatic de-adjustment in 
order to attain constancy of the effective toggle-lever angle. The 
pressure-application arm is also easy to manufacture and does not have to 
be angled as would be necessary to accommodate a toothed section. The 
components of the automatic locking mechanism must be rigidly connected to 
the pressure-application arm or to the moving handle, with of course the 
latch mounted in such a way that it can pivot. The parts must not however 
be capable of mutual axial displacement. Accommodating the toothed section 
on the moving component of the crimper also makes it possible to make the 
section large enough for almost the total closing process to be covered by 
the action of the automatic locking mechanism. Malfunctions of the type 
that occur when only one or two teeth are employed are accordingly 
prevented. The pressure can be reliably adjusted without having to vary 
anything at the effective toggle-lever angle. Wear on the teeth can also 
be adjusted for in this way. The design in accordance with the invention 
finally also makes it possible to accommodate the spring that opens the 
crimper at a more practical point because the automatic locking mechanism 
does not get in the way. Finally, the new crimper is easy and simple to 
handle when adjusting the pressure, which is a particular advantage for 
daily use. 
When the toothed section is in one piece with the moving handle, the 
section will be especially simple to manufacture. It can be in the form 
more or less of an extension of one side of a handle with a U-shaped 
cross-section and will hence be located more or less necessarily in a 
plane paralleling the pressure-application arm, so that it can operate 
directly in conjunction with the latch, which is positioned on the 
pressure-application arm at that point, with no necessity for angling the 
toothed section in relation to the moving handle. 
At least one articulated support can have either an adjustable eccentric or 
an adjustable screw to vary the pressure with. It is of course also 
possible to position the means of adjustment at both points of support. It 
is only essential that the toggle-lever articulation be kept free of means 
of adjustment because adjustment at that point would again lead to varying 
the effective toggle-lever angle. 
The stops that limit the closing motion can in a practical way be 
adjustable to compensate for variations in manufacturing tolerance. Since 
the effective toggle-lever angle remains constant, it is also unnecessary 
to adjust the stops when the pressure is adjusted. The stops can have a 
setscrew that extends through the pressure-application arm with the free 
end of the setscrew operating in conjunction with the moving handle. This 
is also a skillful means of accommodation.

The design of the crimper 1 illustrated in FIG. 1 is in itself known. 
Rigidly connected to the forward end of a stationary handle 2 is a 
crimping jaw 3 equipped with a crimping contour 4. Pivoting on the forward 
end of stationary handle 2 is a moving crimping jaw 5, which also has a 
crimping contour that complements crimping contour 4. It is secured with a 
pin 6. 
Between stationary handle 2 and crimping jaw 5 is a toggle-lever drive 
mechanism that consists of part, specifically a toggle-lever section 18, 
of a moving handle 7 and of a pressure-application arm 8. Moving handle 7 
is articulated to moving crimping jaw 5 at an articulated support 19, and 
pressure-application arm 8 to the rear end of stationary handle 2 at 
another articulated support 20. Also part of the toggle-lever drive 
mechanism, finally, is a toggle 21 that articulates toggle-lever section 
18 to pressure-application arm 8. Pressure-application arm 8 is, as will 
be evident, much longer than toggle-lever section 18, which is represented 
by the interval between articulated support 19 and toggle 21. The ratio is 
at least approximately 2:1 and preferably even higher. The toggle-lever 
drive mechanism is exploited, however, only outside of its extended state, 
avoiding, that is, the position at which toggle 21 rests on the line 
connecting articulated supports 19 and 20. Exceeding the dead center is in 
particular to be avoided. The reason for exploiting the toggle-lever drive 
mechanism only up to just before its extended state is that a spring 9 is 
positioned between stationary handle 2 and moving crimping jaw 5. The 
spring is accordingly capable of opening the crimper again automatically 
once it has arrived at the end of its closing motion and hence at its 
effective toggle-lever angle. 
The articulated support 19 for toggle-lever section 18 and simultaneously 
for the moving handle 7 of moving crimping jaw 5 can have an eccentric 
bolt 16, making it possible to vary the effective distance between 
articulated supports 19 and 20 and hence adjust the pressure between 
crimping jaws 3 and 5 in the closed position or compensate for any play 
resulting from wear. Articulated support 20 can also or solely be 
displaced in the same way, with an eccentric that is. It is, however, also 
possible to position a setscrew 17 in the vicinity of the articulated 
support 20 in stationary handle 2 to displace the support axially within 
the handle. Both adjustment potentials, which can be employed either 
individually or in combination, are intended strictly to adjust the 
pressure at the end of the closing motion. 
The aforesaid transmission or length ratios between the different arms 
provides the crimper with a high transmission, so that a comparatively low 
manual force applied between stationary handle 2 and moving handle 7 will 
result in considerably higher pressure in the vicinity of crimping contour 
4. To ensure that this desirable pressure, or that a pressure sufficient 
for crimping a cable terminal to an electric conductor, will be attained, 
an automatic locking mechanism is provided that consists of two mutually 
engaging components positioned in the vicinity of toggle 21 in association 
with pressure-application arm 8. The automatic locking mechanism 
accordingly has a latch 11 that pivots on a pin 10. A restoring spring 12 
secures latch 11 at the midpoint of its pivot. Latch 11 has a projecting 
pawl 13 that operates in conjunction with a toothed section 14 positioned 
stationary on or in one piece with moving handle 7. Toothed section 14 has 
a number of teeth 22 distributed in the arc of a circle around toggle 21. 
The extent of the curve of toothed section 14 is dictated by the effective 
range of automatic locking mechanism. The extent is preferably long enough 
to engage the automatic locking mechanism over essentially the total 
stroke of the closing motion and to disengage it from teeth 22 only at the 
initial and final position of pawl 13. For this purpose there is in 
relation to the final position an empty space 23 adjacent to toothed 
section 14 on moving handle 7, whereas toothed section 14 terminates at 
the other end, associated with the initiation of a closing motion, also 
resulting in an empty space as will be evident in particular from FIG. 2. 
In the vicinity of toggle 21 there is also a setscrew 15 that extends 
through pressure-application arm 8 and can be adjusted by means of an 
appropriate thread in relation to pressure-application arm 8 in such a way 
that the end of the screw that extends out of the arm projects more or 
less far out and hence operates in conjunction with the back of moving 
handle 7, which can have a U-shaped cross-section. Stops 24 and 25 are 
created at this point, as will be especially evident from FIG. 1. Stops 24 
and 25 prevent the toggle-lever drive mechanism from overextending or 
entering dead center and accordingly limit its swing. An effective 
toggle-lever angle is accordingly established. This occurs in relation to 
the automatic locking mechanism, with stops 24 and 25 coming into contact 
when pawl 13 leaves the last tooth 22 during a closure motion and swings 
into space 23. 
How crimper 1 operates in conjunction with the automatic locking mechanism 
will now be described. 
Commencing with the open position illustrated in FIG. 2 and wherein the 
automatic locking mechanism is initially free, the parts to be crimped are 
positioned in crimping contour 4, and moving handle 7 is pivoted, 
approaching stationary handle 2, so that the toggle-lever drive mechanism 
begins to function and moving crimping jaw 5 is pivoted around pin 6 
toward the closed position. This engages the projecting pawl 13 on latch 
11 with the teeth 22 on toothed section 14. As soon as the first tooth is 
passed, the closing motion can no longer be left or released in that 
direction even if the parts to be crimped were obviously improperly 
inserted. It is accordingly advisable to manually and purposefully lift 
pawl 13 out of the gap between two teeth 22 by activating a trigger 26 on 
latch 11 in order to deactivate the automatic locking mechanism. Usually, 
however, when, that is, the parts have been correctly positioned, trigger 
26 is of course not activated and the closing motion continues until the 
position illustrated in FIG. 1 has been attained, with the automatic 
locking mechanism still engaged although crimping jaws 3 and 4 are almost 
in contact. To attain the final state of a crimping procedure as 
illustrated in FIG. 3 it is now necessary to force moving handle 7 farther 
on into an even closer approximation to stationary handle 2. The requisite 
final pressure against crimping contour 4 is simultaneously attained and 
projecting pawl 13 is released from the teeth 22 in toothed section 14 and 
pivots into space 23. Stops 24 and 25 simultaneously come together and the 
accordingly reproduceably adjusted effective toggle-lever angle can no 
longer be increased. The parts are conventionally crimped and, by 
releasing or by yielding to moving handle 7, spring 9 will be capable of 
opening the crimper automatically because the dead center has been 
avoided. 
The pressure prevailing at the terminal position can be adjusted by varying 
the interval between articulated supports 19 and 20 at either support 
without entailing the simultaneous adjustment of the automatic 
locking-mechanism angle at which it becomes active. Adjustment of the 
pressure is accordingly independent of the action of the automatic locking 
mechanism. The angle at which the locking mechanism opens again remains 
constant. This situation will now be explained with reference to FIG. 4, 
which is a schematic illustration of the relative positions of articulated 
support 19, articulated support 20, and toggle 21, showing that toggle 21 
does not rest against the line between articulated supports 19 and 20 but 
to the right. 
Pressure-application arm 8 and toggle-lever section 18 are represented by 
line segments at effective toggle-lever angle 27, which is as will be 
evident, somewhat less than 180.degree.. Toothed section 14 and latch 11 
are illustrated schematically. Toothed section 14 is rigidly fastened to 
toggle-lever section 18, whereas latch 11 is stationary but pivots on the 
pressure-application arm. The illustrated position is the position at 
which latch 11 has just left toothed section 14 during the course of a 
closing motion. An effective toggle-lever angle 27 is accordingly 
established and further ensured by stops 24 and 25, which establish a 
limiting angle 28. The sum of effective toggle-lever angle 27 and limiting 
angle 28 is 180.degree.. It will be evident that the only essential for 
determining the relative positions of the components of the automatic 
locking mechanism, specifically toothed section 14 and latch 11, in 
relation to attaining release is effective toggle-lever angle 27 and not 
the length of either pressure-application arm 8 or toggle-lever section 
18. Thus, displacing articulated support 20 as represented by the dotted 
line in FIG. 4 and hence adjustment of the effective length of 
pressure-application arm 8 does not lead to a difference in the engagement 
ratios between the components of the automatic locking mechanism, so that 
effective toggle-lever angle 27 will remain constant at the given 
pressure. The same is true for displacing articulated support 19 or 
articulated supports 19 and 20 simultaneously.