Note: Descriptions are shown in the official language in which they were submitted.
Title ~ -~
X-ray Unit
~echnical Field
This invention relates, generally, to
the exposure of X-ray ~ilm and, more particularly,
to ~he handlin~ of such film in a daylight envixon-
ment.
Back~ro~nd
The image of an X-ray film can be
enhanced by the use o intensiier screens lying
intima~ely against opposite faces of the fil~.
Thic could be accomplished by the use of metal
plates at opposite faces of the film-screen
sandwich, except that a metal plate in fron~ of
the ilm will block X-rays. It would be desirable
to provide a simpLe and low cost device which
could hold the film and screens ~ightly together
in a unit during exposure and yet be opened to
enable ~he dispensing of one film sheet at a time
into a space be~ween the screens and tha sub~e-
quent release o.~ the fiLm sheet therefrom a~ter
exposure.
Disclosure of Invention
In accordance with one embodiment o the
present invention, an X-ray unit of relatively
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simple design is provided, which can hold a film in
intimate contact with intensifier scre~ns, and which
enables the insertion of a film between the screens and
the removal therefrom in 2 simple manner. The apparatus
for holding the film against the intensifier screens
includes a resilient backing plate behind the film-
screen sandwhich and a flexible thin sheet lying in front
of the film-screen sandwich, with the opposite sides of
the flexible sheet fastened to a mounting frame. With
the opposite sides of the flexible sheet held to the
mounting frame, a vertical pressing member is moved
against the middle of the backing plate to bend it
forward and push the film-screen sandwich into a curve
that holds the film and screens in intimate contact.
When the pressing member is moved back, a film sheet can
be fed between the intensifier screens or an exposed film
sheet can be allowed to drop out from between the screens
by withdrawing supporting pins that would otherwise
support the film.
Description of Drawings
In the drawings, which occur in the order Fig. 1,
Fig. 4, Fig. 6, Fig. la, Fig. 7a, Fig. 7b, Fig. 7c, Fig~ 2,
Fig. 3, Fig. 5, Fig. 8, Fig. 13, Fig. 14, Fig. 9, Fig. 15,
Fig. 16, Fig. 12, Fig. 10, Fig. ll:
Figure 1 is a partial perspective view of a
chest X-ray unit constructed in accordance with the present
invention, shown with a portion of the lighttight housing
cut away;
Figure lA is a perspective view of a portion of
the unit of Figure 1, showing the manner of construction
of the exposure portion thereof;
Figure 2 is a paxtial rear perspective view of
the unit o~ Figure 1, showing the mechanism thereof;
Figure 3 is a view taken on the line 3-3 of
Figure 2;
ll~Z4~
Figure 4 is a view taken on the line
4-4 of Figure 3;
Figure 5 is a partial view of the
apparatus of Figure 3, showing the manner in
which the pressing member operates;
Figure 6 illustrates three stages in
the operation of the unit of Figure l;
Figures 7a-7c illustrate views taken
on the line 7-7 of Figure 5, the three views
showing ~he unit at different stages of its
operation;
Figure 8 i5 an exploded pexspective
view of the dispenser portion of the unit of
Fig~re 1, showing a film magazine outside of the
lS receiver;
Figure 9 is an exploded perspective
view of the film magazine of ~igure 8;
Figure 10 is a view taken on the line
10-10 o~ Figure 8~ .
Figure 11 is a view ~aken on the line
1l-11 o Figure 10;
Figure 12 is a partial view o the
di~penser por~ion o~ Figure 10, showing it in a
condition wherein a film is almost completely
dispensed from the apparatus;
Figure 13 is a view taken on the line
13-13 of Figure 10;
Figure 14 is a view taken on the line
14-14 of Figure 13;
Figure }5 is a view taken on the line
15-15 o~ Figure 8;
Figure 16 i9 a view taken on the line
16-16 o Figure 15.
Description of A aratus
Fiq. 1 illustrates a chest X-ray unit 10
which includes a main frame 1~, an exposure apparatus
14 mounted along the frame for holding a sheet of
film 16~ a dispenser 18 above the exposure apparatus
for dispensing the film into the exposure apparatus,
and an exposed ~ilm receiver 20 located below the
exposura apparatus for xeceiving the exposed film.
The unit is prepared for operation by first loading
a bulk film magazine 22 in~o a mag~zine-holding
portion 24 of the dispenser. Then, a handle 26
on the main frame is pivoted to an upward position
26u to tip back a mounting frame 28 of the exposure
apparatus 14 to a position for receiving a film
from the dispenser, and a control on panel 30 is
operatea to cause ~he dispensing of a ~ilm into
the exposurs apparatus. After the film has been
received, the handle 26 is moved into a downward
position 26d which causes the ~ilm 16 to be held
20 in the exposure apparatus closely against the
intensifier screens. A patient then can be posi~
tioned in front of a co~er 27 on the exposure
apparatus 14 and an exposure made. Finally, the
handle is moved up to i~s cen~ral position 26 and
the film 16 drops down into the receiver 20.
Fig. 7a illu~trates ~he arrangement of
elements adjacent to film 16 in the exposure
station 14. T~e ilm 16 is sandwiched between a
pair o~ intensifier .~creen~ 32, 34, and the ~creen
and film sand~ich is, in turn, ~andwiched between
a 1exible front ~heet 36 and a resilien~ backing
plate 38. The screens can be permanently attached
to the flexible sheet and pLate, respectivel~ In
order to obtain a uniormly ull expo3ure o the
film 16 using a minimal Le~el of X-rays, the
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s
intensifier screens 32, 34 must be held acewise
against the film at all areas of the film. This
must be accomplished without using a metal plate
or other similar member in front of the film that
could absorb a significant portion of X~rays.
Fig. LA illustrates the basic manner in
which the film 16 is held tightly to all areas of
the intensifier screens 32, 34. The backing plate
38 is constructed of a flexibly resilient material
such as an 0.1 inch (~.54 mm) thick magnesium plate.
The front sheet 36 is constructed o a tough,
-- ~ flexible plastic such as Mylar~ polyester film. ~he
opposite sides 40 of the front sheet are wrapped
somewhat more than 180 about a pair of vertical
mounting rods 42. Each mounting rod is held in a
hole presented by a pair of grooves 44, 46 formed
respectively in inner and outer bars 48, 50 of the
mounting frame 28. The extreme sides of the sheet
36 are wrapped about thin re~aining rods 52 which
20 more securely hold the side of the sheet about tha
mounting rods 42. An elongated ver~ical pressing
bar 54 extends behind the middle of the backing
plate, halfway between the opposite sides of the
front sheet. When the pressing bar 54 is moved for~
wardly, in the direction o~ arrow F, it bends the
backing plate 38. Since ~he opposite sides 40 of
the ~ront sheet 36 are prevented from moving for-
wardly, the backîng plate, intensifier screens,
film and front sheet a~e all pushed into a gentle
curve (Fig. 7b), with the intensifier screens 32, ~4
and ~ilm 16 between them pressed into intimate con-
tact at all areas of the ilm. The intensifier
screens then can aid in achieving uni.formly full
exposure of the film. O course, it would be possi-
b}e to fix the position of the pressing bar 54 and
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instead move back the opposite sides of the frontsheet.
The pressing or pu~her bar 54 is a~ached
~o a forward channel memb~r 56. As shswn in Fig. 5,
the channel member 56 carries a pair of rollexs 58,
60 which bear against a rearward channel member 62.
The rearward channel member 62 has a pair of
inclined slots 64, 66 at its upper and lower ends
which receive a pair o cam members 68, 70 fixed
to the mounting ~rame. In addition, a chain 72
is provided to pull down the rearward channel member
62 against the bias of springs 73 ~Figs. 2 and 3).
Springs 73 extend between the fixed rod that mounts
cams 68 and a rod 75 that extends through the
flanges of channel 62. When the channel member
62 is pulled down, the cams 68, 70 force the rear-
ward channel member to move forward, to push the
rsllers 58, 60 forward~ and therefore to move ~he
forward channel member 56 and pusher bar-54 ~or-
wardly.
Fig. 2 shows that the hain 72 that pullsdown the rearward channel member 62 extends around
a rotatable pulley 74 and up ~o a tensioning pulley
76. The tensioning pulley 76 is ~ixed to an
operating shaft 78 ~o which the handle 26 is
fixed. Thus, when the handle 26 is moved down-
wardly, the chain 72 is pulled to cause the ~i~m
and the intensifier sheets to be bowed ou~wardly
and into intimate contact.
Fig. 6 show~ the three positions 28a,
28b, 28c of the mounting rame. ~t 28a~ the top
o the mounting rame is til~ed back to receive
the ilm 16. At position 28b, the mounting ~rame is
vertical and the intensiier screens are held
tightly against the film in preparation ~or exposure
L5~
of ~he ~ilm. At 28c, the mounting frame is ver~i-
cal, but the film is looseLy disposed between the
intensifier screen~ so that the film 16 can drop
down between a pair of rollers 80 in film receiver
20.
Fig. 3 sh~ws a cam 82 which i~ fixed to
the operating shaft 78 and which controls backward
pivoting of ~he mounting frame 23. When the handle
26 is ~urned to position 26u, shaft 78 rotates and
the cam 82 assumes position 82a; then, the mounting
frame 28 can pivot back about an axis 84 to the posi~
tion Z8a. At that position, the space between the
intensifier scre~ns is aligned with a guideway 86
through which a sheet of film is dispensed. Sprlngs
}5 88 bias the top of the mounting frame rearwardly to
assure such tipping. When the shaf~ 78 is turned
so that th~ cam is at position 82, the c~m forces
the mounting ~rame upri~ht. However, even at the
cam position 82, the shaft 78 is not ~urned far
enough for the chain 72 to be pulled tight. Whe~
the shaft 78 i5 turned so the cam is at position
8~b, the cam still holds thé mounting frame upright,
. but the tensioning wheel 76 on the shaft is then
rotatqd far enough to pull the chain 72 tightly
enough to pull down the rearward channel member
62 so as to causa its ~orward mo~ement that holds
the film in Lntimate contact with the intensifier
screen~. Af~er exposure of a film, the handle 26
and cam 82 are moved to their middle position and,
as shown in Fig. 7c, a pair o~ 11m holding pins
83 are moved back to allow the ilm 16 to drop
into the exposed ~ilm receiver 20 ~Fig. 1).
Pins 83 extend laterally from arms 87
that are pivoted on a sha~t 89. Arms 87 have tabs
that engage stops on cakches 90 that are pivoted
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on a shaft 91. As channels 56, 62 are moved
rearwardly, ater an exposure, catches 90 pivot
arms 87 sufficientLy to move pins 83 out from
beneath the exposed f~lm 16 ~Fig. 7c). After the
exposed film has dropped to receiver 20, the
operating handle can be moved to position 26u.
With the mounting frame in position 28a, another
film can be dispensed through ~uideway 86. As
the frame moves to position 28a, the ends of catches
90 engage shaft 78 and the catches are pivoted
sufficiently to move the stops away from the ~abs ---
on arms 87. When freed in this manner, arms 87
swing forwardly in response to the action of springs
92 and pins 83 move into th~ir film-supporting
position (Fig. 7a). When a film has been dispPnsed,
the operating handle i5 moved to position 26d. As
the handle moves, the channels 56, 62 move forward,
a~d the screens move together (Fig. 7b). During
~hese movem~nts, the stops on catches 90 fall i~
behind the tabs on arms 87. With the handle i~
position 26d, the intensifier screens 32, 34, with
~he film 16 therebetweenr can lie a~ least about
three inches forward o the dispenser 18, or at
least ~he bottom por~ion thereof, where the head
of a patient would be positioned during the taking
of a chest X-ray.
Following an exposure, handle 26 is
moved to its central position. Rearward movement
o~ channels 56, 62, responsive to the action of
springs 73, also move3 catches 90, arms 87 and pins
83 rearwardly. As noted previously, withdrawal
o~ the pins 83 ~Fig. 7c) releases the exposed ~ilm
to receiver 20.
Figs. 8-16 illustrate details of the
film dispenser 18 which dispenses one film at a
~ 5~;7
time into the exposure apparatus. As shown in
Fig. 8, the holding portion 24 of the dispenser
has a cover 100 that can be swung open to xeceive
the film-holding magazine 2Z. The ~ilm magazlne
22 has a lid 102 at the top that can be opened to
receive a stack of film sheets in a darkroom and
which then can be closed to make the magazine
lighttight. As the magazine 22 is installed in
the holding portion 24, it encounters a pair of
pins 104 that open a light seal at the bo~tom a~d
a receptacle 106 that receives a mating plug on the ---
mag~zine. Fig. 10 illustrates the light seal lO~
at the bottom of the magazine 22, and shows the
pair of rods llO that are attached to the light
seal. Fig. 12 illustrates ~he magazine 22 installed
in the holder portion 24 of the dispenser, showing
how the pins 104 an the holder depress the rods
llO to slide ~he light seal 108 against biasin~
of springs 112 so tha~ a film sheet 16 can pass
down through the dispenser~
- As illu~trated in Fig. 10, the magazine
22 includes a vertical pusher plate 114 whose
upper end carries a pair of guides 116 that can
move forwardly along downwardly inclined guide-
ways lI8 in a pair of guide plates 120. Thepusher plate 114 is therefore urged by gravity to
move forward, to push a stack of film 16S forwardly
and down along an inclined support plate 122. As
the ~ilm moves forward and down ~he support
plate 122, the frontmoRt film i9 caught between
a dispenser roller 124 and blocks 126 at the bottom
o~ the pusher plate. The blocks 126, which are
especially uqeful for pushing the last ~ilms of
the stack into the roller, are constructed of low
friction material such as a Delrin~ acetal resin.
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The low friction material of the blocks 126 aids
them in sliding down alony a lower support plate
127 and in assuring that when the blocks push the
last film against the drive roller 124 the blocks
do not retard the film from moviny down.
The forward edge 122e o~ ~he upper
support plate 122 is accurately spaced from the
drive roller 124 to form a throat 12~ betwe~n them
that penmits only one sheet to pass down ~hro~gh
the throat. Thus, for ilm sheets of ten mils
(thousandth of an inch or 0.0254 mm) thickness r ~~~~
khe edge 122e may be spaced a dista~ce such as
twelve mils ~0.0305 mm) from the roller. Also
the edge 122e may be formed of a low friction
material such as a Teflon~ fluorocarbon resin to
facilitate the passage o~ film thereby.
The magazine is normally loaded with
film in a darkroom by laying ~he holder horizon-
tally and then laying a stack of film on the p-usher
pla~e 114. When the holder is tu~ned to the vertical
as shown in Fig. 10, or is moved around, it is
possible ~or more than one sheet to be pushed into
the space above the support plate edge 122e and
the drive roLler 124. In order to avoid jamming
of film, a backup member 128 is provided which can
push the stack of film rearwardly, to push back
sheets which have started to gather in and above
throat space 129 and the roller. The backup member
128 is pivotally mounted at 130 and ha~ a button
132 protruding ~rom the ~ilm holder housi.ng to
enable a technician to press the button a~ter he
has loaded the ma~azine 22 in holding portion 24.
The backup member is also useul in that when its
e~d 128e pushes back the stack and quickly releases
it, the member bends the sheets and "shakes up" the
~ z~
stack. Any film sheets which have not ~allen
down firmly onto the support plate 122 will do
so, and the film sheets will lie in a more uniform
arrangement for reliable dispensing.
When the film maga~ine 22 has been
installed in the holding portion 24 of dispenser
18, a drive pin 134 (Fig. lS) at the end of the
drive roller 124 lies in the pa~h o~ a dri~e tab
136 which lies on a motor ~riven wheel~ When a
proper button on the control panel 30 of the unit
is deprassed, the drive roller 124 is rotated, as
indicated in Fig. 10, to move down one ~ilm sheet
past a microswitch 138, the thin arm of the micro-
switch deflecting out of the way of the film. The
film then passes through a guideway 140 and through
the guideway 86 into the exposure apparatus 14.
Microswitch 138 is connected to a power source
and to control panel 30 through receptacle 106.
The combination of the support plate
edge 122e which is accurately spaced from the roller
124, the pusher plate 114 which holds the film
upright and gently push~s it against the roller,
and the bac~up member 128 which can push back and
slightly bend the stack to help avoid sticking of
the sheets to one another, all combine to assure
regularity and evenness in the stack and therefore
reliable feeding of only one shee~ a~ a ~ime past
the roller. If a sheet is not fed, which is
sensed by lack of operation of the microswitch 138,
the technician ~an back up and slightly bend the
stack once or twice, and again operate the roller
to dispen~e a ilm sheet. Thus, by assuring that
the sheets are well positioned in the magazine,
uniorm dispensing o~ the sheets is achieved.
11
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Accordlngly, the in~ention provides
an X-ray unit which enables the daylight loading
of one sheet at a ~ime into an exposure station
and the tigh~ holding of that film shPet to in~en-
sifier screens at the exposure station, all witha relatively simple and low cost apparatus. The
close holding of the ~ilm sheet to the intensifier
screens i5 accomplished by the use of a flexible
plastic sheet, whose opposite sides are securely
held, a resilient backing plate, and a pressing
bar that pushes along the center line~ of the
resilient backing plate to de~orm it forwardly.
The mounting frame that holds the flexible front
sheet, backing plate, and pressing bar is pivotally
mounted to enable its top to pi~ot back to xeceive
a new sheet of ~ilm from a dispenser located far
enough behind the exposure station to avoid
interferenc with the taking of chest X-rays.
The combina~ion of a pusher pl~te and backup member
2û whi~h assurP a uniformly held s~ack or ~ilms sheets,
allows for reliable dispensing of one sheet at a
time.
The application is a division o~ copending
Canadian Serial No. 305 242, filed 1978 June 12.
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