X-ray or gamma ray systems or devices – Source support – Including movable source
Reexamination Certificate
2001-02-08
2002-07-23
Kim, Robert H. (Department: 2882)
X-ray or gamma ray systems or devices
Source support
Including movable source
C180S019300, C180S019100, C378S193000
Reexamination Certificate
active
06422747
ABSTRACT:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to an X-ray photographing apparatus of a power driving type which moves forwardly or backwardly in response to a force of an operation handle. More particularly, the present invention relates to a movable type X-ray photographing apparatus, which includes bridge circuits for driving formed of switching elements; driving motors, each being positioned at a center of the bridge circuit; and pulse width control circuits for controlling ON-OFF duty of torque of the motors by the bridge circuits.
FIGS.
2
(
a
) through
2
(
c
) show a movable type conventional X-ray photographing apparatus. FIG.
2
(
a
) shows a front view of the movable type conventional X-ray photographing apparatus; FIG.
2
(
b
) shows a side view; and FIG.
2
(
c
) shows a plan view. This apparatus is formed of an X-ray tube
18
; an arm
19
for supporting the X-ray tube
18
; a column
20
which is rotatable on a truck or base
21
; an ascending and descending section in which the arm
19
moves vertically or up and down along the column
20
; and freely rotatable or pivotable front wheels
23
and rear wheels
22
(right wheel
2
and left wheel
1
) which are incapable of steering. The truck
21
is provided with an X-ray control section, and moves forwardly or backwardly by means of driving motors (a right motor
6
and a left motor
5
) provided at a lower section when a lever handle
14
disposed in a handle supporting base
17
attached to the truck
21
is operated forwardly or rearwardly.
The arm
19
, which includes a supporting mechanism for the X-ray tube
18
and a rotational mechanism therefor and extends or retracts horizontally, moves smoothly vertically along the column
20
, so as to be balanced. A collimator (X-ray radiation port) of the X-ray tube
18
is directed to any directions and spatial positions in accordance with a photographing portion of a subject, that is, a person to be examined.
Since the weight of the movable type X-ray photographing apparatus may become more than 450 kg, it is very difficult to move the truck or base without help of the power. In general, a rear portion of the truck
21
is provided with a pair of rear wheels
22
, which are attached not to be steered, and a front portion of the truck
21
is supported by a pair of casters. That is, front wheels
23
are freely rotatable or can be turned. The rear wheels
22
are generally driven by the driving motors (the right motor
6
and the left motor
5
) mounted in the truck.
The truck
21
includes an internal power supply formed of an automobile battery and an inverter with a main circuit of 100-120 V and 60 Hz, and the truck
21
also includes a high-voltage transformer and a condenser. In many cases, there is used an apparatus of a one-touch system, wherein a control circuit thereof is solid-systematized and a photographing operation is automatically programmed.
Also, rubber tires or the like are used in the truck
21
, so that the apparatus can freely enter or leave a patient's room, an operating room, or an elevator, and the truck
21
also includes a brake system, a cassette box, and accessories.
It is important that the movably type X-ray photographing apparatus is small, light-weight, and excellent in a moving operation ability as a mobile type apparatus. Also, the X-ray photographing apparatus is easily moved to a bedroom, a technician room, an operating room, a children room or a pediatric room, an X-ray room, an infant room or the like in a hospital, and conveniently used for an X-ray photographing or radiography at a job site, that is, the location where the apparatus is moved.
FIG. 3
shows a control block diagram of the movable type X-ray photographing apparatus. A left wheel
1
and a right wheel
2
shown in an upper section in
FIG. 3
are respectively driven by the left motor
5
and the right motor
6
, and the left motor
5
and the right motor
6
are individually controlled by a motor driving circuit
9
through a left output
7
and a right output
8
. The motor driving circuit
9
is subjected to a switching control by pulse width modulation (PWM) by means of a PWM control circuit
10
. A duty control width of the switching control is controlled by a signal from a CPU (central processing unit)
35
. When an operator operates the lever handle
14
of the truck
21
forwardly or rearwardly, signals from a left pressure sensor
15
and a right pressure sensor
16
disposed at both ends of the lever handle
14
are individually inputted to the CPU
35
as a left input
12
(left Ft) and a right input
13
(right Ft).
On the other hand, from a left encoder
3
and a right encoder
4
, which are respectively provided at axles of the left wheel
1
and the right wheel
2
and detect rotational speeds, signals of a rotational speed Vt at left and a rotational speed Vt at right are inputted to the CPU
35
. Then, the CPU
35
controls the PWM control circuit
10
with PWM control width which is proportional to the input signals Ft of the forward or backward movement from the left pressure sensor
15
and the right pressure sensor
16
. Accordingly, the motor driving circuit
9
is actuated, and the left motor
5
and the right motor
6
are rotated at output torque T. The rotational speeds Vt of the motors are detected by the left encoder
3
and right encoder
4
, and the speed signals Vt are inputted to the CPU
35
.
If the rotational speeds Vt are lower than a predetermined rotational frequency or number corresponding to the input signals Ft, the PWM control width is enlarged, and if the rotational speeds Vt are higher than the aforementioned predetermined rotational frequency or number, the PWM control width is narrowed. The rotational speeds are fed back and controlled. The CPU
35
inputs the duty control width signal corresponding to the PWM control width into the PWM control circuit
10
; the PWM control circuit
10
controls the motor driving circuit
9
; and the motor driving circuit
9
controls the rotational speeds V of the left motor
5
and the right motor
6
.
The lever handle
14
is connected to the truck
21
through spring members which are relatively rigid but flexible. The spring members connected to both sides of the truck
21
are formed of hard plate springs, and by providing these spring members, the position of the lever handle
14
can be changed slightly in the front and rear directions in response to the force applied to the lever handle
14
, such as a force for pushing or pulling the lever handle
14
.
At both ends of the lever handle
14
, a pair of linear magnets moving together with the lever handle
14
is respectively attached. On the other hand, a pair of Hall-effect sensors (the left pressure sensor
15
and the right pressure sensor
16
) is attached to the truck
21
, and disposed respectively adjacent to the corresponding magnets. The Hall-effect sensors are respectively connected to power supplies (not shown). When the Hall-effect sensor (left pressure sensor
15
or right pressure sensor
16
) is located at the center positions with respect to the magnet, an output signal of the Hall-effect sensor (left pressure sensor
15
or right pressure sensor
16
) become zero level. When the magnet is moved or displaced, the output signal of the Hall-effect sensor (left pressure sensor
15
or right pressure sensor
16
) changes approximately linearly between the positive maximum value and the negative maximum value. The code of the sensor signal, that is, polarity, shows the direction of the displacement of the lever handle
14
, and the magnitude of the sensor signal is proportional to the amount of the displacement.
By operating the lever handle
14
forwardly and rearwardly, the lever handle
14
can be relatively easily displaced by the spring action of the spring members, and at the same time, when the lever handle
14
is released, the lever handle
14
can be quickly returned to a neutral position or a center position.
The conventional X-ray photographing apparatus is stru
Akutsu Koji
Araki Tatsuya
Kanesaka & Takeuchi
Kim Robert H.
Shimadzu Corporation
Wang George
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