US006111215A

United States Patent [19]

[11] Patent Number:

Lilly

[45] Date of Patent:

[54]

[76]

6,111,215
Aug. 29, 2000

MINATURE BATTERY POWERED ARC

5,086,208

WELDER

5,233,159
5,250,786

8/1993 Day .................................... .. 219/130.1

10/1993 Kikuchi et al. .

5,410,126

4/1995 Miller et al. ....................... .. 219/1301

Inventor:

Leslie G_ Lilly, 1750 Via paci?ca,

#N101, Corona, Callf. 91718

2/1992 Habermann .

FOREIGN PATENT DOCUMENTS

56-77068

6/1981

Japan ................................ .. 219/1304

2316244
97/34727

2/1998
9/1997

United Kingdom .
WIPO .

[21]
[22]

Appl' NO" 09/178256

Filed;
Oct 23, 1998

[51]

Int. c1.7 ..................................................... .. B23K 9/09

Primary Examinerclifford 0 Shaw

[52]

US. Cl. ............................... .. 219/130.51; 219/137 PS

Mom?) Agent 0 FimRbe" D- Fish> E59; Fish &

[58]

Field Of Search .......................... .. 219/1301, 130.21,

Assoclates> LLP

219/13031, 130.32, 160.33, 130.4, 130.51,

[57]

ABSTRACT

132, 137 PS
[56]

A hand carried, or hand-held, portable, arc Welding appara

tus. Designed to provide a variable square Waveforrn Weld

References Cited

ing current output. Powered by sealed high discharge rate,

us PATENT DOCUMENTS
1,509,006 9/1924 Thomas,

gel-cell, rechargeable batteries that, are sealed for safety. A

new form of Welding technology is provided for saving

2,091,871 8/1937 Meier.

2,487,582 11/1949 Parris .
2,836,703 5/1958 B9346 -

energy and making autornated tack Welds. A neW self

diagnostic feature is provided for safe operation. A remote
control option is provided as Well as a Way to control the

1;;
,

ilerntm'
vers en

heating and cooling of the Weld. Duty cycle control and

.

3,301,996

1/1967 Bidwell .............................. .. 219/130.1

4,484,055
4,590,357

11/1984 Hainesetal. ........................... .. 219/75

5/1986 Winkler .

4,801,780

1/1989 Hayes ................................. .. 219/1301

frelllncy Control are provlded for e?iclent Control of the

We

mg process

5 Claims, 9 Drawing Sheets

L1 46

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169

182

U.S. Patent

Aug. 29, 2000

F 172
REVERSE
V

OUTPUT

6,111,215

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116
0

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POLARITY

HIGH
CURRENT
FREQUENCY
CONTROL

DUTY
CYCLE
FREQUENCY
CONTROL

II
A
A

160
20

L
f

"

18

CURRENT

L LIMITING
162
V
_

FAN

'

CONTROL

4
164
L/

__+

(62

PULSE

WELD

__

14

166

>

REGULATED
POWER
SUPPLY

I)

SHORTED
>

OUTPUT

TRANSISTOR
: \,16
168 \

Fl

REMOTE

CONTROL

U.S. Patent

Aug. 29,2000

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6,111,215
1

MINATURE BATTERY POWERED ARC

WELDER

FIG. 5 is a diagram illustrating the construction of the fan

control circuit.
FIG. 6 is a diagram illustrating the construction of the
shorted transistor circuit.
FIG. 7 is a diagram illustrating the construction of the
high current power switch circuit.
FIG. 8 is a diagram illustrating the construction of the

BACKGROUND

1. Field of Invention

This invention relates to battery powered, portable, hand

carried arc welding apparatus.
2. Description of Prior Art
Traditional ac powered arc welding machines, used in

reverse output polarity option circuit

10

FIG. 9 is a diagram illustrating the construction of the

commercial applications, have usually been large, heavy and

remote control pulse weld option circuit.

bulky. And required large amounts of ac power. However,

they were usually provided with abundant features and
controls that, allowed the welding operator to make higher
quality arc welds. Such as: Reverse polarity output, precise
current control, square waveform output, current slope

FIG. 10 is a diagram illustrating the construction of the

remote control current limit option circuit.
FIG. 11 is a diagram illustrating the construction of the

15

remote control duty cycle and frequency option circuit.

FIG. 12 is a drawing illustrating the construction of the

adjustments, frequency control, interval timer and other

devices not mentioned here. Most battery powered, portable,

remote control enclosure.

hand carried arc welding machines lack most or, all of

REFERENCE NUMERALS IN DRAWINGS

features that are common on ac powered welding machines.

Therefore, most battery powered arc welding equipment is,

not suitable for most arc welding requirements. Most battery
powered arc welding equipment lack an efficient way for

controlling current. They are usually somewhat large, heavy,

and bulky, and usually not very practical in operation.

25

OBJECTS AND ADVANTAGES

Several objects and advantages of the present invention

are:

(a) to provide a compact, portable, battery powered,

ef?cient arc welder that is hand-held or hand-carried.

(b) to provide a battery powered arc welder that has duty

cycle control.
(c) to provide a battery powered arc welder that has

35

frequency control.
(d) to provide a battery powered arc welder that has a
square waveform output.
(e) to provide a battery powered arc welder that has nickel
cadmium batteries or gel cell batteries.
(f) to provide a battery powered arc welder that has

precise output current limiting.

(g) to provide a battery powered arc welder that has
remote control operation.
(h) to provide a battery powered arc welder that can make

45

automated tack welds from a hand-held welder.

(i) to provide a battery powered arc welder that can

control the length of the weld.
to provide a battery powered arc welder that has self

11

cable

14

battery

16

common

18
20

cable
switch

21

capacitor

22

nor gate

23

capacitor

24
26

nor gate
nor gate

28

potentiometer

30

nor gate

31

capacitor

32

switch

33

capacitor

34
36
38
40
42
44
46
48
50
52
53
54

resistor
transistor
buffer
buffer
resistor
transistor
transistor
transistor
inverter
inverter
diode
switch

56
58

potentiometer
capacitor

59
60
61

cable
diode
switch

62

diagnostic features.

comparator

63

connector

64
65

potentiometer
capacitor

(k) to provide a battery powered arc welder that can

66

resistor

control the heating and cooling of the welding process.

68

regulator

(1) to provide a battery powered arc welder that can help

prevent the welding rod from sticking to the material

55

being welded.
DRAWING FIGURES

FIG. 1 show a block diagram of the basic construction of

this invention
FIG. 2 is a diagram illustrating the construction of the

duty cycle and frequency controller.

FIG. 3 is a diagram illustrating the construction of the

pulse weld circuit.

FIG. 4 is a diagram illustrating the construction of the
current limiting circuit.

65

70

motor

72

potentiometer

74

comparator

75
76
77
78

transistor
diode
transistor
resistor

80
82

potentiometer
regulator

84
86
88
9O
91

timer
transistor
diode
diode
transistor

92

lamp

93

resistor

6,111,215
3

-continued

ers. To make continuous welds, adjust potentiometer 28 as

shown in FIG. 2 and frequency selection switch 32 for the
type of weld desired. For lowest frequency welding use

94

alarm

96

nand gate

98
99
100
102
104
106
108
110
112
114
116
118
120
122

transistor
diode
transistor
transistor
transistor
transistor
transistor
varistor
resistor
diode
terminal
terminal
snubber
thermistor

124
125
126
127
128
130

relay
relay
relay
relay
relay
relay

132
134
136
138
140

switch
switch
switch
switch
switch

contact
contact
contact
contact
coil
coil

141

potentiometer

142

switch

144

potentiometer

146
148

switch
resistor

149
150
151
152

capacitor
capacitor
capacitor
capacitor

153

rod holder

160

current limiting

162

fan control

164
166

pulse weld
shorted output

168
169

remote control
enclosure

172
174

reverse output polarity

high current power
switch

176

duty cycle frequency

178

control
load

position 33. And, for highest frequency welding, use posi

tion 23. Next make a few test welds and, notice which

frequency/duty cycle 28 combination setting gives the

desired results. Try making overhead, and vertical test welds
and, observe, which settings obtain the best results.
FIG. 3 shows the control circuit for making pulse-welds,
10

15

180

reactor

cable

184

welding rod

duty cycle frequency setting 21,23,31,33 shown in FIG. 2.

The on/off pulse-weld 164 frequency 56 is independent of
the duty cycle 28 and frequency 21,23,31,33 setting. This
pulse-weld on/off frequency will provide control of the
amount of tack welds made per second. Pulse-weld fre

quency control is provided by potentiometer 56 and capaci

tor 58.

FIG. 4 shows the current limiting circuit 160 which is

20

used to limit welding current to a desired amount whether,

tack welding, or normal welding. Potentiometer 64 is pro

vided for this purpose. FIGS. 5,6 shows that the heatsink

25

cooling fan motor is provided with automatic temperature

sensing on/off operation using a thermistor 122 as shown in
FIG. 7. This motor 70 is dc operated. A shorted transistor
98,100,102,104,106,108, as shown in FIG. 7 and a diagnos
tic circuit as shown in FIG. 6 is provided to warn the

operator that a dangerous fault condition exists and, the

welder switch 20 should be turned off immediately.
30

FIG. 8 allows the welder operator a way to reverse the output

polarity without removing and exchanging the welding

cables. Remote control operation as shown in FIGS. 9,10,11

provides a way for remote operation when switch 134,136,

140,142 are turned on. Switch 146 allow remote operation of
35

transistor

182

or tack welds. Turning on switch 54 will start the pulse-weld

circuit. The welding output current will go on and off at the

40

frequency control by offering various frequency positions as

shown in FIG. 11. Remote potentiometer 144 provide duty
cycle control. Remote Potentiometer 138 provide indepen
dent frequency control for tack welding only.
Remote potentiometer 141 provide current limiting control
for welding current. Capacitors 149,150,151,152, provide
the same function as capacitors 21,23,31,33 and allow the
circuit to oscillate at a frequency determined by the value of

the capacitor selected by the frequency selection switch 146.

SUMMARY

45

The object of this invention is to provide a low cost, more

OperationFIGS. 1, 12

ef?cient, hand-held, battery powered, arc welding apparatus.

Switching transistor output cable 11 is connected to

transistor 98,100,102,104,106,108 and terminal 118. Battery
positive cable 18 feeds switch 20 and reverse output 172
and, power switch 174 and, terminal 116.
Remote control cable 59 and, remote connector 63 pro
vide remote control logic to remote enclosure 169.
Welding rod holder 153 provides a way to hold the

welding rod 184 while welding. Welding cable 182 is

connected to reactor 180 and rod holder 153. Remote
enclosure 169 is attached to rod holder 153 to provide a
convienient way for the welding operator to use remote

50

automatic fault indicating diagnostic system. It is still

55

146.
60

located on the main welder enclosure and, is not located on

the remote enclosure 169. Switch 61 must be in the remote

position to provide control logic for all remote control

devices.

OperationFIGS. 2,3,4,5,6,7,8,9,10,11
The manner of using the minature battery powered arc
welder is generally, similar to most conventional arc weld

another object of this invention to introduce remote control

operation.
DETAILED DESCRIPTION OF PREFERRED
EMBODIMENTS

potentiometers 138,141,144 and frequency selection switch

Remote control four pole, double throw, switch 61 is

It is another object of this invention to provide most features

found on conventional ac powered arc welding equipment.
It is still another object of this invention to introduce pulse
weld technology in a hand-held, hand-carried welder. It is
still another object of this invention to introduce an internal

65

Battery power 14 provided by the 24 volt high discharge

gel cells 14 provide welding current on demand. Output
transistors 98,100,102,104,106,108 allow welding current to
?ow from the 24 volt battery 14 to the welding load 178
through connectors 116 and 118. Switch 20 provides control
voltage to operate all control logic functions. The duty cycle
controller 176 provides pulse width modulation. It is used to
control output transistors 98,100,102,104,106,108. In other

6,111,215
5

Words, by varying the pulse Width or duty cycle, the Weld

Resistor 78 is part of thermistor 122 voltage divider circuit.

Resistor 66 and capacitor 65 provide noise reduction from
the Welding current feedback signal.

current Will also vary. therefore this is an excellent system

to use to control the Welding current. When Welding current

exceeds the operator current control potentiometer 64, the

Fan control 162 operates by turning the adjustable voltage

duty cycle control 176 output control signal is reduced by

the current limiting 160 circuit, resulting in reduced Welding

poWer supply 68 on and off by comparator 74. When its

output is high, the heat sink cooling fan motor 70 is

current to Within the operator desired current limits 64.

When sWitch 54 is turned on it, Will alloW the astable
multivibrator 50,52 to begin pulsing on and off, at a fre

controlled by actual heat sink temperature by comparator 74.

A heat sink mounted, negative temperature coef?cient ther

quency set by potentiometer 56 and capacitor 58. This Will

circuit With resistor 78. By providing a signal into compara

tor 74, that is compared With the set point of resistor 80.
Therefore, Whenever the thermistor 122 output signal
exceeds that of potentiometer 80, the output of comparator
74 Will be high. Turning on transistor 75, Which Will turn off

mistor 122 operates as a serarate part of a voltage divider

1O

alloW a high state pulse to turn on transistor 36 and Will noW

reduce the duty cycle control signal through resistor 34 to

near Zero.

When transistor 36 is turned on, no Weld current Will ?oW

transistor 77 and, making regulator 68 output high. Driving

during the on interval. Due to lack of the duty cycle signal

on the gates of transistors 98,100,102,104,106,108. During
the off interval, the output of multivibrator 50,52 is in a loW
state. AlloWing transistor 36 to remain off until the next high
state pulse arrives at the base of transistor 36. Therefore, the
duty cycle control signal Will resume at its former setpoint
28,56,64. AlloWing Weld current to ?oW, due to the duty
cycle control signal on the gates of transistors 98,100,102,
104,106,108. In other Words, in the pulse Weld mode, the
Welding current Will turn on and off until stopped by the

15

operator. The on/off frequency is determined by potentiom

25

multivibrator 22,24 running, at a frequency chosen by the

frequency select sWitch 32,146. The duty cycle is set by

potentiometer 28, an d 144. Nor gates 26,30 provide a
buffered output to, drive a cmos, non-inverting buffer 38,
and interfaces With a ttl non-inverting buffer 40, that has
open collector outputs. These open collector outputs, are
used to pull resistor 42 doWn to near Zero volts, on negative

pulses, thereby removing the base drive from transistor 44.

eter 56 and capacitor 58. Potentiometer 28 Will control the

duty cycle. Potentiometer 64 Will control current limiting or
Welding current. When the Welding current is turning on and
off at a, operator set frequency 56 it is referred to in this
patent application, as pulse Weld 164. It is designed to alloW
the Welding operator to make automated tack Welds to save

This Will make transistors 98,100,102,104,106,108 turn

off, and not alloW any Weld current to How into the load 178
from connectors 116,118. Transistor 46 is turned on by the

same negative pulse, and provides a Way to discharge the

stored gate capacitance on the gates of transistors 98,100,

102,104,106,108.
When a positive pulse arrive at pull-up resistor 42, and the
base of transistor 44, transistors 98,100,102,104,106,108

energy. Frequency selection 32 is provided to also help

prevent the Welding rod from sticking to the material being
Welded. Still another bene?t for the Welding operator is,
there is no need to lift the Welding rod up off of the material

the cooling fan motor at a speed set by potentiometer 72.

A cmos quad, 2 input nor gate 22 comprise an astable

Will turn on alloWing Weld current to ?oW into the load 178
from connectors 116,118. Diode 114 serves as a fast
35

being Welded, every time a tack Weld is required.

recovery, free Wheeling diode across the load 178. Metal

oxide varistor 110 provides a Way of controlling unWanted,

automated fashion With this Welder. This Welder Will alloW

voltage transients across the load 178. The snubber 120

protects the drain 118, and source 16 connection from

an operator to make more and faster tack Welds per linear

voltage transients that could ruin transistors 98,100,102,104,

foot. Another bene?t from this Welder is, since these are tack

106,108.

Therefore, it is noW possible to tack arc Weld in an

Welds, and not regular Welds, more Welds per battery charge

The amount of controllable Weld current ?oWing into the

are noW possible. Less battery 14 energy is required to make

load 178, is pulse-Width, or time dependent. Comparator 62

provides current limiting by comparing the Weld current
?oW through resistor 112 With, the operator adjusted, current
limit set point potentiometer 64. When the current limit
setpoint is exceeded, comparator 62 output Will go high,
turning transistor 36 on, and driving the collector load of
transistor 36, Which is resistor 34 loW.

a tack Weld because of the short on duration of energy

leaving battery 14. When sWitch 54 is turned off all Welding

Will be semi-continuous, or continuous Welds depending on
the frequency selected by sWitch 32. This should alloW more

45

ef?cient overhead, vertical and ?at Welding results. This is

made possible due to the ability to control the on and off time
of the Welding current How in the Welding load 178.

The duty cycle signal travels through resistor 34, and is

Herein described as the duty cycle 28 and frequency selec

normally high. Except When transistor 36 is turned on, the

tion 32. AloWer on frequency, Will alloW more cooling of the

duty cycle signal is made loW, preventing this signal from

material being Welded. While, a higher on frequency, Will

alloW less cooling of the material being Welded. Herein

Without gate drive no Weld current can ?oW into the load

arriving at the gates of transistors 98,100,102,104,106,108.

referred to as the load 178. Output Welding current is

178. Zener diode 99 provides gate protection against voltage
smoothed by an external inline current reactor 180. The 55 transients.

reverse polarity option 172 is controlled by sWitch 132.

SWitch 132 energiZes normal 128 relay, and reverse 130

Transistor 48 is energiZed only during overcurrent con

ditions. And provides a clamp to help control gate imped

relay. Relay contacts 124,126 provide current reversal, While

ance during overcurrent conditions. A timer 84 is con?gured

contacts 125,127 alloW normal polarity. Remote control 168

as a poWer-up one shot astable multivibrator, providing a 15

operation, is arranged through a four pole double throW

sWitch 134,136,140,142.

to 20 second duration positive output pulse. Therefore, this

Aseparate control cable from the Welder enclosure, to the

remote location, is provided to connect the remote control
components 138,141,144,146 Which, are mounted in a small
enclosure, attached to the Welding rod holder. This Will

timers output Will go high, every time the on-off sWitch 20

is turned on, and stay loW after it has timed out. It is used to
control the shorted output transistor circuit 166. Also to

alloW a convenient remote operating location for the Weld

remove the duty cycle signal by turning on transistor 36

during the one shot timing duration.
When the duty cycle signal is off, no Weld current should

ing operator. Resistor 148 provides gate signal equaliZation.

?oW. except When there is a shorted transistor drain 118 and

65

6,111,215
8

7
source connection 16. The shorted transistor 166 circuit Will

a duty cycle controller controlling the duty cycle of a

Work only When the timer 84 output is high turning on

transistor 86, allowing current to flow through lamp 92 and,
turning on transistor 91, driving resistor 93 loW, driving r-s
latch nand gate 96 output high. When nand gate 96 is high,

pulsed current flowing from the current source and into

the rod holder;

a pulse Weld controller controlling the How of the pulsed
current to the rod holder and causing the pulsed current

it Will latch transistor 74 on until it is reset by turning off

sWitch 20. Alarm horn 94 Will also latch on.
If, there is a shorted transistor 98,100,102,104,106,108

current will flow through transistor 86, lamp 92, and block
ing diode 90, and continue through the shorted transistor

to turn on and off at a ?xed tack Weld frequency;

the tack Weld frequency and duty cycle being independent

of each other.
2. The arc Welding apparatus of claim 1 further compris
10

drain connection 118 and source connection 16. No gate

signal should be present. Afterwards the alarm and fault

indicating lamp and horn 94 Will be latched on until sWitch

20 is turned off. Regulator 82 Will provide regulated voltage

to all logic circuits.

15

Although the description above contain many

speci?cities, these should not be construed as limiting the
scope of the invention but merely providing illustrations of
some of the presently perferred embodiments of this inven
tion. For example, the siZe of the Welders enclosure can be
larger or smaller than minature, or the battery can be more
or less than 24 volts. Thus the scope of the invention should

be determined by the appended claims and their legal

equivalents, rather than by the eXamples given.

I claim:

1. An arc Welding apparatus comprising:

ing a transistor and an internal test circuit Which measures

the impedance across tWo terminals of the transistor and

prevents current from ?oWing from the current source to the

25

electrode if the measured impedance drops beloW a thresh

old value.
3. The arc Welding apparatus of claim 2 further compris
ing an enclosure positioned on or adjacent to the rod holder,
the enclosure comprising controls for varying at least one of
the duty cycle, tack Weld frequency, and current limit of the
pulsed current ?oWing into the rod holder.
4. The arc Welding apparatus of claim 3 further compris
ing a cable through Which the pulsed current flows on its
Way into the rod holder, and a current smoothing reactor
located in the cable.
5. The arc Welding apparatus of claim 4 Wherein the
apparatus is siZed and dimensioned to alloW the apparatus to

be hand-held during operation.

a battery poWered current source;

a rod holder coupled to the current source;