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Патент USA US2126957

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Aug. 16, 1938.
E. R. GOLDFIELD
2,126,957
TIMING MEANS FOR X'RAY APPARATUS
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Filed Jan. 2, 1937
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INVENTOR
EDWIN R. GOLDFIELD
TTORN Y6 I
2,126,957
Patented Aug. 16, 1938
UNITED STATES PATENT OFFICE
2,126,957
TIMING MEANS FOR X-RAY APPARATUS
Edwin E. Gold?eld, University Heights, Ohio, as
signor, by mesne assignments, to Picker X-Ray
Corporation Waite Manufacturing Division,
Inc., Cleveland, Ohio, a corporation of Ohio
Application January 2, 1937, Serial No. 118,756
5 Claims.
(Cl. 250—34)
This invention relates to means for controlling
the operation of an X-ray tube and more par
ticularly to means for limiting the time of tube
primary winding of the transformer l and the
function of the transformer 3 being to supply a
low voltage current for energizing the coil 2a of
operation.
the relay switch 2 to close the latter and thus per
mit energization of the tube A, subject to the 5
means to be described.
For control of the coil 2a a pair of switches 4
and 5 are arranged in series relation therewith in
In fiuorcscopy it is important to limit the total
time of exposure of a patient, at the same time
providing separate periods of exposure with in
tervals therebetween, and to this end it is an
object of this invention to provide means which
10 may be preset by the operator to limit the total
time of tube operation and thus of exposure, while
permitting interruption of operation at the will
of the operator. Another object is to provide
signal means for indicating the expiration of the
15
predetermined operating period.
Frequently in practice a number of patients
aremet in succession, the time limit upon each
of which is identical, and a further object of the
invention is to provide convenient stop means for
20 similarly presetting the same time limit for such
number of patients in succession. Further the in
vention embraces novel provision against acci
dental shifting of such stop means, to improve
the safety of the apparatus which, of course, is
operated largely in av dark room. Another object
that the coil will be energized and the switch 2
thus closed, only when both the control switches
4 and 5 are closed, the control circuit then being
closed from the tap of the transformer 3 through
switch 4, switch 5, coil 2a and back to the near
15
end of the transformer.
The switch 4 may be located convenient for
control by the operator as adjacent the ?uoro
scopic screen to be employed in connection with
the tube A. It may be of a pedal operated type
closed by foot pressure and spring balanced to
open position.
The switch 5 is a sensitive normally closed one
may be made at one location, whereas the inde
pendent exposures may be controlled thereafter
having a plunger 5a, pressure upon which
will open the switch and upon release of which
plunger the switch will automatically reclose. 25
Further details of the switch are not important
here.
This switch 5 is arranged to be opened auto
by the operator at another location, as adjacent
matically to serve as a time limit switch and to
is to provide that the presetting of the time limit
the ?uoroscopic screen.
While the invention is particularly adaptable
to fiuoroscopy, it might also be employed to ad
vantage in connection with X-ray therapy as
will be apparent to one familiar with the art.
The exact nature of this invention together with
further objects and advantages thereof will be
apparent from the following description taken
in connection with the accompanying drawing,
in which Fig. 1 is a conventionalized view show
ing diagrammatically apparatus illustrative of
the invention; Fig. 2 is a face view of the time
limiting unit showing the parts in a diiferent po
sition from that of Fig. 1; Fig. 3 is a detail of
parts appearing in Fig. 1 taken as in the plane of
line 3-3, Fig. l; and Fig. 4 is an enlarged de
tail partly in section, showing the parts positioned
as in Fig. 1.
With reference now to the drawing, A is an
X-ray tube served through the usual high tension
50 transformer I supplied with alternating current
55
a control circuit as indicated in the drawing, so
from the line L1, L2, through the operating cir
cuit illustrated and including a relay switch 2
and auto-transformer 3, the relay switch being
preferably employed for the usual reasons and,
also as usual, located in series relation with the
this end a synchronous motor 6 is connected in
parallel relation with the coil 2a as indicated
in Fig. 1, so that the motor will operate coin
cidently with energization of the coil 2a and
consequent energization of the tube A.
For immediate control of the switch 5, a cam ‘I
is provided having a lobe la capable of pressing
the plunger 5a to open the switch 5 acting through
a spring 51) — so that the switch will be opened
or closed dependent upon the position of the
cam 1. Means are provided for driving the cam
‘l by the motor 6 to open the switch 5, such means
including a connection generally indicated at 8
and preferably reduction gearing conventionally
indicated at 9, the motor driving the gearing and
the latter driving the cam through the device 8.
The driving device 8 is of such nature that it
will provide timed drive of the earn 1, clockwise,
Fig. 2, and will permit adjustment of the cam rel
ative to the motor, in the opposite direction. In
the drawing a spring 8a bearing the friction disc
81) against the cam, is indicated for the pur
pose.
Conveniently the motor 6, switch 5, and de
scribed parts interconnecting them, are enclosed
within a housing l0. For adjustment of the cam
2
2,126,957
‘I from Without this housing, a knob l I is provided
outside the housing and positively connected with
moved dependent upon the time of the exposure.
As shown in Fig. 2, such exposure has been
the cam ‘I as by a shaft Ila, so that the cam
slightly over 11/4 minutes, leaving slightly under
1% minutes remaining for other exposures of the
may be adjusted by the operator, against the
friction device 8 and thus independent of the mo
tor '6. The knob ll carries a pointer Ilb which
moves over a scale upon the face of the housing
I0, the pointer I lb being so related to the lobe ‘Id
of the cam ‘I, and the scale being so calibrated as
10 in minutes, with respect to the speed of the motor
same patient.
When the operator is ready for his next expo
sure he again closes the switch 4 i‘ or so long a time
as desired, the parts operating as before.
When the maximum total preselected time has
been exhausted by the several exposures, the cam 10
6 and reduction provided by the gearing 9, and
‘I opens the switch 5, deenergizing the tube A inde
the parts being otherwise so proportioned and ar
ranged, that time units are accurately indicated
to the operator and that when the pointer llb
pendent of the switch 4, by deenergizing switch 2,
and the operator knows that the time limit of
indicates zero on the scale, the cam ‘I will close
the switch 5.
Signal means may be provided, for indicating
opening of the switch 5 when the switch 4 is
closed. Such means is here shown as a neon tube
20 I4, located to be visible to the operator, and con
nected in the circuit in parallel relation to the
switch 5.
Stop means are provided for positively limiting
adjustment of the knob I I from its zero position.
25 For this purpose as here shown a plate I2 is
secured on the face of the housing Ill, having a
series of notches I2a. A stop lever I3 is mounted
for free movement on the shaft Ila beneath the
knob ll having an upturned lug l3a engageable
by the pointer I lb of the knob I l, having a ?nger
I32)‘ engageable in one of the notches I211, and
having an upturned handle part I30.
The stop I3 is of spring material so that it yield
ably maintains its ?nger I 3b in whatever notch
l2a the latter may be positioned. Adjustment of
the stop to another notch thus requires a sequence
of motions in different directions, ?rst outwardly
from the housing In to withdraw its ?nger I31)
and then about the shaft Ila. It is to be noted
40 therefore that the stop is positively positionable
by any of the notches I 2a, is practically incapable
of accidental displacement when so positioned yet
can easily be shifted when such is the operator’s
desire.
Operation of the apparatus will be as follows,
commencing with the switch 4 open, the knob l l
in zero position and the line L1, L2, connected to a
suitable source of alternating current supply.
The switches 2 and 5 are now open, neither the
motor 6 nor the tube A being in operation.
The operator having determined what maxi
mum total exposure from the tube A is safe for the
instant patient, sets the knob II and its stop I3
correspondingly. For example, in Fig. 2 of the
Cl UK drawing the stop is indicated as located for a
3-minute total exposure. It is convenient for the
operator to ?rst so set the stop and then simply
move the knob ll up to the stop. Such adjust
ment of the knob moves the cam 1 against the
(50 friction device 8, permitting the switch 5 to close.
The apparatus is then preset for the desired
fluoroscopy.
The operator having suitably arranged his
patient and being now located adjacent the switch
4, when operation of the tube is desired simply
closes the switch 4 for so long a time as one expo
sure is desired. The switch 5 being already
closed, closing of the switch 4 completes the circuit
for the coil 2a, closes the switch 2 and causes oper
70 tion of the tube A. Instantly the tube begins to
operate, so does the motor 6 driving the cam ‘I
toward its zero position.
When the operator opens the switch 4, the tube
A and motor 6 are both deenergized, leaving the
75 cam ‘I to whatever position it may have been
exposure has expired. The switch 5 thus acts as
an automatic limit switch for total time whereas
the switch 4 is an operator-controlled switch for
controlling merely the individual exposures, both
these switches acting on the tube through the
relay switch 2.
Once the limit switch 5 is open, any closing of 20
the exposure switch 4 by the operator will com
plete an energizing circuit for the signal device I4
and thus indicate that the tube cannot be oper~
ated.
Should the same total time be proper for the
next patient, as is frequently the case, it is obvi
ously unnecessary that the operator readjust the
stop l3. If the room be darkened he need merely
again move the knob II from its zero position
until it engages the stop, with assurance that the
stop has not been moved from the position in
which he initially set it.
What I claim is:
1. Apparatus for the purpose described, com
prising an X~ray tube, operator-operated exposure
switch means, time limit means, and means inter»
associating said tube and exposure switch means
and time limit means in a manner to provide oper
ation of said tube in successive periods responsive
to said exposure switch means, to provide meter
40
ing operation of said time limit means only during
tube operation, and to provide operation of said
time limit means to prevent said tube operation
beyond a predetermined total time attained dur
ing said periods.
45
2. Apparatus for the purpose described, com
prising an X-ray tube, operator-operated expo
sure switch means, time limit means, means asso
ciating said tube and exposure switch means and
time limit means in a manner to provide operation 50
of said tube in successive periods responsive to
said exposure switch means, to provide metering
operation of said time limit means only during
tube operation, and to provide operation of said
time limit means to prevent said tube operation 55
beyond a predetermined total time attained dur—
ing said periods, operator-operated means for
presetting said time limit means to a selected tube
operating time limit, and adjustable stop means
for said presetting means.
3. Apparatus for the purpose described, com
prising an X-ray tube and its operating circuit, a
control circuit for said operating circuit including
in series an operator-operated switch, a time limit
switch and motor means, a timing device arranged
to be driven by said motor means, said device
being arranged to open said time limit switch
upon completion of the operating cycle of said
timing device, and a control member for said
operating circuit energized coincidently with said
control circuit.
4. In apparatus having an X-ray tube, an oper
ating circuit therefor, a relay switch in said oper
ating circuit, time limit switch means and a syn
chronous driving motor therefor, a control circuit
2,126,957
for said relay switch, an exposure switch in series
relation with said time limit switch and said
motor in said control circuit, and an energizing
coil for said relay switch in parallel relation with
said motor.
5. In apparatus having an X-ray tube, an oper
ating circuit therefor, a relay switch in said oper
ating circuit, time limit switch means and a syn
chronous driving motor therefor, a control circuit
3
for said relay switch, an exposure switch in series
relation with said time limit switch and said
motor in said control circuit, an energizing coil
for said relay switch in parallel relation with said
motor, and signal means arranged in said control
circuit to be energized when said relay switch is
open while said exposure switch is closed.
EDWIN R. GOLDFIELD.
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