Welding-wire feed monitor

A device for monitoring the movement (advance or velocity) of an electrode wire comprising a measuring roller against which the wire is urged by a pressing roller flanked by a pair of grooves in a housing. The wire is captured in these guide grooves by a jaw carried by a lever swung in the housing, thereby greatly simplifying the opening and closing movements of the device.

FIELD OF THE INVENTION 
My present invention relates to a monitoring device capable of responding 
to the advance of a welding wire and/or to the speed of a welding wire for 
a welding machine or station utilizing the wire as a filler wire or 
consumable electrode. More particularly, the invention relates to a device 
for measuring the advance or speed of a welding wire by causing the wire 
to entrain a measuring roller which can be connected to a signal generator 
whose output represents the advance of the wire or its speed. 
BACKGROUND OF THE INVENTION 
In many welding applications, the feeding of a welding wire, i.e. a wire 
which can be melted to form the weldment (filler wire) or a wire which is 
used as an electrode to strike the arc, must be monitored with care to 
ensure, for example, a constant feed rate. 
Monitoring devices are provided for this purpose on welding machines and 
can be a measuring roller or wheel against which the welding wire is 
displayed and which can be pressed against this wheel by a pressure 
roller. 
The measuring roller or wheel is coupled to a signal generator, usually a 
pulse generator, which can produce a pulse for each increment or advance 
of the wire. The number of pulses thus represents the length of wire fed 
and the frequency or cadence of the pulses, i.e. the number of pulses per 
unit time, can represent the speed of the wire. Each pulse also represents 
an increment of angular displacement of the measuring wheel or roller and 
a constant rate of pulse generation can signal a constant speed of the 
wire. 
If the pulses are counted or otherwise accumulated in a pulse counter, the 
total value will represent the weld material consumed in a particular 
process. 
Earlier monitoring devices were relatively complex and had a particular 
problem in that it was difficult to insert the wire into the monitoring 
device, particularly when the wire had to be threaded through wire guides 
fore and aft of the measuring roller. 
In one conventional system for this purpose, to insert the wire into the 
guide grooves on either side of the measuring and pressing rollers, it was 
necessary to loosen a pair of screws which held guide plates in place, to 
shift these plates until the grooves were exposed, to insert the wire and 
pass it between the rollers, and to replace the plates and the screws. 
This process was time-consuming and had to be repeated each time a fresh 
length of wire was supplied to the welding site. 
OBJECTS OF THE INVENTION 
It is the principal object of the present invention to provide a welding 
wire monitor for the purposes described which permits more rapid insertion 
or removal of a welding wire and thereby conserves time and effort in the 
welding process. 
Another object of this invention is to provide an improved monitoring 
device for the speed and velocity of a welding wire which greatly 
simplifies the introduction of the wire into the device and especially 
into guides thereof. 
Still another object of the invention is to provide an improved easily 
operated, simple and readily maintainable welding-wire monitor. 
SUMMARY OF THE INVENTION 
These objects and others which will become apparent hereinafter are 
attained in accordance with the present invention in a welding wire 
displacement and speed monitoring device which comprises a housing 
provided with a measuring roller or wheel, a pressing roller to hold the 
welding wire against the measuring roller which can be provided with a 
signal generator producing an output representing the angular displacement 
of the measuring roller and hence of the welding wire in contact 
therewith, and wire guides flanking the measuring roller at least in the 
region of contact of the wire therewith and including grooves in which the 
wire can be received. 
According to the invention, the housing is provided with a lever pivotally 
mounted about an axis generally parallel to the direction of wire 
displacement through the device. At its end remote from this axis the 
lever is provided with jaws cooperating with the guide for retaining the 
wire in the respective grooves so that, upon a pivotal movement of the 
lever, the jaws swing away to clear the grooves and allow insertion of the 
wire into the grooves. 
According to a feature of the invention, the pressing roller is also 
mounted on this end of the lever and is flanked by the jaws. The lever is 
swingable between two limiting positions, e.g. by an actuating mechanism. 
In one of those limiting positions, i.e. the open position, the guide 
grooves are open toward a side of the housing and the wire can be inserted 
into these grooves. In the other or closed position, the jaws cooperate 
with the groove-carrying members to entrap the wire in the grooves. 
For insertion of the wire, therefore, it is merely necessary to operate the 
actuator, e.g. by hand, to lift the end of the lever and shift the latter 
into its open position. 
According to yet another feature of the invention, the actuator includes a 
further lever which is fulcrumed in the housing and has a handle which 
projects therefrom and is engageable by the hand of the user. This 
actuating lever can be connected to the first mentioned lever by a link 
articulated to both levers. The handle can be actuated readily by only one 
hand of the operator so that the other hand can be used to insert the 
welding wire. 
A spring can be provided in the housing and biases the actuating system so 
as to close the grooves, the spring being compressed for opening of the 
grooves. So that the angular displacement of the lever provided with the 
jaws can be held as small as possible, it has been found to be 
advantageous to shift the pivot axis of this lever toward the actuating 
end of this lever or, put otherwise, to provide the actuator more closely 
to the fulcrum of this lever than are the jaws. In this case the actuating 
arm is significantly shorter than the actuated arm.

SPECIFIC DESCRIPTION 
As can be seen from FIG. 1, the device comprises a housing 2 having a pair 
of narrow lateral walls 2a, 2b, a full height rear wall 2c and a somewhat 
shortened front wall 2d, the latter terminating below the upper portion 1a 
of a measuring roller 1 which is journaled by a pin 1b in the housing. The 
roller 1 is connected with a signal generator 1d which outputs to leads 1e 
a train of pulses at a frequency representing the velocity of a wire 
electrode 1c which is passed through the monitoring device. The leads 1e 
are passed through an insulating structure 21 which also forms a handle in 
case the device must be hand-held from which the conductor 22 emerges. 
A lever 5 is fulcrumed at 13 within the housing, the axis of the fulcrum 
parallel to the wire and being located to the left-hand end of the lever 5 
than to the right-hand end. To this end, the lever 5 has two lever arms 7 
and 8, the former being for shorter than the latter. 
At the end of the lever arm 8 there is provided a jaw 17 with a pair of 
curved jaw surfaces 17a which are juxtaposed with the open end of a pair 
of guide grooves 18 formed on members 16 which project toward the member 
17a. When the grooves receive a wire electrode which is shown for the 
electrode 1c in FIG. 1, the surfaces 17a cooperate with the ends of 
members 16 to trap the electrode in the grooves. The jaw 17 carries a 
pressing roller which is mounted to rotate parallel to roller 1 in the 
position shown in FIG. 3. 
The actuating system for the lever 5 comprises, as can be seen at 4, a 
lever arrangement. A link 15 is articulated at 19 to the lever 5 at a 
location close to the fulcrum 13 so that the end carrying the jaw 17 
swings significantly even for a small angular displacement of the lever 5. 
The opposite end of the link 15 is articulated at 20 to an actuating lever 
6 fulcrumed at 12 within the housing and having two lever arms 9 and 10 
which are about the same length. A finger-operated button or handle 9a is 
provided at the free end of the arm 9 and can be engaged by a finger, e.g. 
the thumb of the user, when he is holding handle 21. 
A compression tube coil spring 14 bears upon the lever 6 and tends to 
rotate in the clockwise sense and to rotate the lever 5 in a similar 
sense. The spring maintains the grooves 18 close until member 9a is 
actuated against the force of the spring 14. 
When the lever 6 is actuated, by pressing member 9a upwardly, the lever 5 
is swung into its open position unblocking the grooves 18, and permitting 
the welding wire to be inserted into the grooves and over the top of the 
wheel 1. 
When the lever 6 is released, the spring 14 closes the lever 5 and brings 
the wheel 3 against the welding wire, thereby clamping the welding wire 
between the wheels and ensuring that any further movement of the welding 
wire will result in entrainment of the wheel 1 and a corresponding output 
of the signal generator 1b. Obviously, this system allows high-speed 
one-hand opening and closing of the device so that the other hand can be 
utilized to let in the electrode wire.