JPH01178242A - Bed height display apparatus - Google Patents

Abstract

PURPOSE:To display the moving distance of a bed in the height direction thereof with high accuracy by measuring the moving quantity of a moving frame from a detection signal by an encoder and deciding the height display data corresponding to the measured moving quantity to display the same. CONSTITUTION:A- and B-phase pulse signals different in a phase are outputted from the encoder 5 mounted to a link mechanism 3, which allows a moving frame 2 in a direction wherein a horizontal direction component and a vertical direction component are synthesized, corresponding to the movement of the horizontal direction component of the moving frame 2 and the phases of the pulse signals are discriminated by an encoder pulse input circuit 11 to discriminate the moving direction of the moving frame 2. Further, the incremental or decremental pulse signal corresponding to said moving quantity is given to an incremental decremental counter 13 and, on the basis of the data corresponding to the moving quantity of the vertical direction component of the moving frame 2 preliminarily stored in a ROM 24 with respect to the moving quantity of the horizontal direction component of said frame, height display data is judged and displayed on a display device 17 through a driver.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is directed to a bed height system that displays the height of a bed movable in the height direction with high accuracy, for example, used in an X-ray CT scanner. Related to display devices.

(Prior art) For example, in an X-ray CT scanner, a bed on which a subject is placed is moved in the height direction to adjust the height so that the area to be imaged falls within a predetermined imaging range, and the height of the bed at that time is adjusted. The height of the bed is displayed based on the amount of movement in the horizontal direction.

By the way, such a conventional bed height display device winds up or rewinds a filament attached to the top of the bed using a winding bobbin provided at the bottom of the bed according to the movement of the bed in the height direction. There is a device in which the rotation of the winding bobbin is transmitted to a potentiometer, and the value is converted from analog to digital and displayed on a display unit. in this case,
The winding bobbin is biased by spring force so that it can always rotate in a fixed direction.

(Problem to be Solved by the Invention) However, in such a bed height display device, as the bed descends, the filament wound on the winding bobbin becomes double or triple, or On the other hand, as the bed rises, it doubles,
As the wire is unwound from the triple-wound state, the winding diameter changes, so the winding bobbin does not rotate at a speed proportional to the amount of downward or upward movement of the bed. It is not possible to display the exact height. Also, at first glance it seems like a simple configuration to prevent the filament wound on the winding bobbin from bunching up and to always apply spring force in a fixed direction, but it is surprisingly simple. This results in a complex structure.

Furthermore, since the rotation of the winding bobbin is detected by a potentiometer and the output is converted from analog to digital to display the bed height, gain adjustment and offset are required, as well as the rise and fall limits of the bed. If the moving distance between the two is relatively long, it is difficult to display the height in units of 1 mm. For example, suppose the distance between the rise limit and the fall limit of the bed is 600 mm, and the analog/digital conversion data is 0 +++n.
OV +.

If 6001 is 12V, the voltage per 1 mm is 12
V/600mm -20m V/1 no
It becomes ++. Therefore, the length of the travel distance is 600 n
+n+ or more, or the voltage is less than 12V, the voltage at 1 mm will be less than 20mV, and in the worst case, the noise generated from the switching power supply itself will affect the display. It becomes difficult.

To provide a bed height display device that can measure the moving distance of the bed in the height direction with a simple configuration, without requiring any adjustment of the measurement system, and can display the height with high accuracy. The purpose is to

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention includes a movable frame on which a bed top is placed parallel to a fixed frame, and A link mechanism is provided that connects the moving frames to move the movable frame in a direction that combines a horizontal component and a vertical component, and the link mechanism is driven by a drive source to move the movable frame in the height direction. An encoder is rotatably attached to the horizontally moving end of the link mechanism and detects the amount of movement of the horizontal component of the moving frame, and the encoder detects the movement of the moving frame by distinguishing the phase of the detection signal output from the encoder. a direction determining means for determining the moving direction of the frame; a measuring means for measuring the amount of movement in the direction when the direction determining means determines the moving direction of the moving frame; a storage unit that stores data corresponding to the amount of movement of the vertical component relative to the amount; and a storage unit that determines height display data that corresponds to the amount of movement measured by the measuring means based on the data stored in this storage unit. The structure includes a determination means for determining the height, and a display means for displaying the height based on the display data determined by the determination means.

(Function) Therefore, in the bed height display device having such a configuration, when the moving frame is moved by the link mechanism and the amount of movement of the horizontal component is detected by the encoder, the moving direction of the moving frame is determined from this detection signal. is determined, and the amount of movement in that direction is totaled Al11. Then, determine height display data corresponding to the measured movement amount based on data corresponding to the movement amount of the vertical component with respect to the movement amount of the horizontal component of the moving frame stored in the storage unit in advance, By displaying the determination result on the display unit, the height of the bed can be displayed with high accuracy even if the moving distance in the height direction of the bed is long.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

First, we will discuss the case where the movable frame on which the bed top is placed is moved in the height direction by the link mechanism as shown in Fig. 1. In Fig. 1, 1 is the fixed frame;
Reference numeral 2 indicates a movable frame disposed parallel to the fixed frame 1, and 3 indicates a link mechanism provided between the fixed frame 1 and the movable frame 2 on both sides in the longitudinal direction thereof, facing each other. This link mechanism 3 intersects a pair of links 3a and 3b, pivots this intersection, and pivots the upper end of one of the links 3a to a U-shaped rail 2a provided inside the moving frame 2. As shown in FIG. 2(a), the lower end is movable via a roller that fits into a U-shaped rail 1a provided inside the fixed frame 1. Then, the lower end of the other link 3b is pivoted to a U-shaped rail la- provided inside the fixed frame 1, and a roller that fits into the U-shaped rail 2a is attached to the upper end to make it movable. be.

Therefore, for example, the link 3 of such a link mechanism 3
When the drive rod 4a of the hydraulic cylinder 4 is connected to the drive rod 4a of the hydraulic cylinder 4 and the driving force is transmitted to the link 3b, the link 3b rotates about the other end pivoted on the fixed frame 1 as a fulcrum, and the movable frame 2 moves. The movement will be in the direction in which the movement of the horizontal component and the movement of the vertical component are combined.

Now, like this, fixed frame 1 and moving frame 2
In the link mechanism 3, which is provided between the link mechanisms 3 and facing each other on both sides in the longitudinal direction, for example, an encoder 5 is attached to the lower end of the link 3b via a support plate 6 as shown in FIG. 2(b). A roller 5a attached to the rotating shaft of the encoder 5 can be rotated along a guide rail 7 attached to the outer surface of one side of the fixed frame 1. When the link 3b is driven by the hydraulic cylinder 4, the encoder 5 rotates the roller 5a due to the movement of the link 3b, and outputs a pulse signal in accordance with the number of rotations.

FIG. 3 shows a block circuit for displaying the bed height based on the pulse signal output from the encoder shown in FIG. In FIG. 3, 5 is the encoder shown in FIG. 1, and this encoder 5 outputs, for example, A-phase and B-phase pulse signals having different phases depending on its rotation.

Reference numeral 11 denotes an encoder pulse input circuit to which A-phase and B-phase pulse signals having different phases from the encoder 5 and a clock signal from the oscillator 12 are input. It discriminates the phase and outputs a count-up or count-down pulse signal according to the rotation speed. 13 is an up/down counter circuit that counts up or down pulse signals applied from the encoder pulse input circuit 11, and this up/down counter circuit 13 receives preset bed height display data from an arithmetic processing circuit to be described later. It is now possible. In this case, the clock signal from the oscillator 12 is applied to the up/down counter circuit 13 via the frequency divider 15, and preset data is set while counting up or down pulse signals from the encoder pulse input circuit 13. This is to prevent it from happening. Further, 15 is an arithmetic processing circuit (CPU) which takes in count data counted by the up/down counter circuit 13 and performs processing to be described in detail later from this count value to determine the corresponding height display data. The arithmetic processing circuit 15 receives a detection signal from a height detector S16 which is turned off when it detects that the bed height has reached the lower limit of the photographing range, and when the height detector 16 is turned off, the count value and display are The data is now initialized. 17, when the display data of bed height is determined by this arithmetic processing circuit 15,
It is a display device that digitally displays this display data on a display section made of, for example, an LED.

FIG. 4 shows the internal configuration of the arithmetic processing circuit 15 using a block circuit. In FIG. 4, 21a and 21b
is a counter buffer that temporarily stores the count data counted by the up/down counter circuit 13 in FIG.
M) written to 22. In addition, 23a and 23b are RA
The count data written in M22 is shown in Figure 3.
This is a counter buffer that temporarily stores data when presetting it in the down counter circuit 13. 24 is a read-only memory (ROM), and this ROM 24 stores in advance height data corresponding to the amount of movement of the vertical component calculated for the amount of movement of the horizontal component of the moving frame. Reference numeral 25 denotes a determination processing unit that plays a central role in processing and determining count data, and this determination processing unit 25 is connected to the RAM 22.
The count data written in the ROM 24 and the height data stored in the ROM 24 are read out, it is determined to which range of the height data the count data corresponds, and this is output as display data. 26a and 26b are display buffers that temporarily store the display data determined by the determination processing section 25.
The display data stored in 6b is sent to drivers 27a and 27.
The images are displayed on the display 17 via the respective channels b. Furthermore, 28 is a port selection section, and this port selection section 28 selects the counter buffers 21a and 21b or 23a and 23b, selects the RAM 22 or ROM 24, and selects the display buffer 26a or 26b according to instructions from the determination processing section 25. This is what we do. In the diagram, 3
0 is a backup power source for the RAM 22 during a power outage.

Note that when the power check circuit 29 detects that the power is off, the determination processing section 25 operates the counter buffers 21a and 2.
It has a processing function of writing the count data of 1b into the RAM 22, and setting the count data of the RAM 22 to the counter buffers 23a and 23b when power-on is detected. It also has a function of initializing count data and display data when the height detector 16 shown in FIG. 3 is turned off.

Next, the operation of the bed height display device configured as described above will be described.

First, how to obtain the height data stored in the ROM 24 shown in FIG. 4 will be described with reference to FIGS. 5 and 6. Fifth
In the figure, when a force is applied to the link 3b of the link mechanism 3 in one direction a-a by the hydraulic cylinder 4, the link 3a
, 3b cardinal branch d.

As these move in a circular motion about e as a fulcrum, the moving frame 2 moves in a direction that is a combination of the horizontal component of c-i-c and the vertical component of b-b'.

Now, when considering the link 3b, the locus of the point f of the sliding portion is as shown in FIG.

In FIG. 6, the vertical axis represents the vertical axis of movement when the horizontal axis of movement of point f of the slide portion of the link 3b is plotted at equal intervals of 150 mm, for example. That is, when the length from the pivot point e of the link 3b to the slide section f is, for example, 1350 mm, and when the movable frame 2 is set to the lowest height, the pivot point e of the horizontal component where the slide section f of the link 3b is located is If the distance (e - cl) from the pivot point e is 1200 mm, then the distance from the pivot point e of the vertical component where the slide part f of the link 3b is located (e b 1 ) + that is, the height is b, -1350-12002-618, 46 cities. Similarly, (]-c2, C2-C3,
...B2 to b6 when C5→c6 are as follows.

BL at C1 (1200mm) -618,48
mmC2 (b2-848. when 1050105O.
b 3-100 at 53mmC5 (900mm)
G, 23mmc, + b when (750m1M)
4- b5 when 1122.49mmcs (GOllmm) - 1209.3mmc6 (450+
+++s) b 6 = 1272.79mm
Therefore, moving frame 2 has C1 as a horizontal component.
When moving ~c6, each vertical component, that is, the change in the amount of movement in the height direction, is b 1- b 2-230, '05 mmb2-b
3-157.70 report bi b, -116,26 mm b-+ b5 = 86.84 mm b5 b6 = 63.49 mm.

The data in the height direction relative to the amount of movement of the horizontal component of the moving frame 2 obtained in this way is stored in advance in the ROM 24.
is memorized. In this case, data in the height direction relative to the amount of movement of the horizontal component is stored in the ROM 24 as a count value of the number of pulses corresponding to the amount of change in the amount of movement in the height direction.

In addition, contrary to the above case, the movement amount of the vertical component of the sliding part f point of the link 3b is plotted on the vertical axis at equal intervals 1, for example, 150
It is also possible to calculate 01 to C6 using the same calculation method as described above, taking the horizontal axis as the horizontal axis, and use the amount of movement of the horizontal component in the height direction as the height data.

Now, when the link mechanism 3 is driven by the hydraulic cylinder 4, this link mechanism 3 drives each link 3a.

The movable frame 2 moves in a direction that is a combination of the horizontal component and the vertical component by making a circular motion around the pivot point 3b and moving its sliding portion along the guide rails la and 2a. At this time, the encoder 5 attached to the sliding portion of the link 3b sends out A-phase and B-phase pulse signals having different positions of 10 in accordance with the movement opening of the horizontal component, and these pulse signals are applied to the encoder pulse input circuit 11. The encoder pulse input circuit 11 discriminates the phase of the A-phase and B-phase pulse signals and inputs a count-up or count-down pulse signal to the up/down counter circuit 13 depending on whether the moving frame 2 is rising or falling. On the other hand, at this time, in the arithmetic processing circuit 15, the RAM 22 is
The count data written in is the count buffer 23a.

23b, and this data is further preset in the up/down counter circuit 13.

Therefore, in this up/down counter circuit 13, if there is a count-up pulse signal from the encoder pulse input circuit 11, this pulse signal is added to the count value corresponding to the bed height up to that point.
On the contrary, if it is a countdown pulse signal, the count is subtracted from the count value corresponding to the bed height up to that point. The data counted by the up/down counter circuit 13 in this manner is temporarily stored in the counter buffers 21a and 21b of the arithmetic processing circuit 15, and then written to the RAM 22. In the determination processing unit 25, the RA
The count data written in M22 and the above-mentioned height data stored in ROM24 are taken in, the height data corresponding to the count data is determined, and the height data is converted into display data and displayed. buffer 26a.

26b and displayed on the display 17 via drivers 27a and 27b. Here, a specific example of converting height data to display data will be described with reference to FIG. Now, if the count value stored in the counter buffers 21a and 21b is, for example, 2951 to 3030, the corresponding height data is determined from among the height data shown in FIG. 7 stored in the ROM 24, and this height data is The display data corresponding to the data, in this case, for example, the display data is all “0” and the count value is 3051 to 3200.
If so, the corresponding height data is determined from among the height data, the display data corresponding to this height data is converted to "1", and this is displayed on the display 17.

As described above, in this embodiment, the encoder 5 attached to the link mechanism 3 that moves the moving frame 2 in the direction that combines the horizontal component and the vertical component changes the phase according to the movement of the horizontal component of the moving frame 2. Different A-phase and B-phase pulse signals are output, and the phases of these pulse signals are discriminated by the encoder pulse input circuit 11 and the moving frame 2 is output.
The up/down counter circuit 13 is provided with a count-up or count-down pulse signal corresponding to the movement start, and the vertical component is determined relative to the movement amount of the horizontal component of the moving frame 2 stored in the ROM 24 in advance. Uploaded based on data corresponding to the amount of movement of /
The height display data corresponding to the count value counted by the down counter 13 is determined, and the display data is displayed on the display 17 via drivers 27a and 27b.

Therefore, as shown in FIG. 6, the moving frame 2 counts the number of pulses according to the amount of movement of the horizontal component when it always moves with a constant curve in the direction that combines the horizontal component and the vertical component, Since the vertical component movement amount is obtained from the count value and converted to height display data,
If, for example, the lower limit of the CT imaging area is set as the initial value for bed height display, highly accurate height display becomes possible.

That is, in the case of the conventional potentiometer method in which the filament is wound or unwound onto a winding bobbin and an electrical signal is obtained from a potentiometer by the rotation of the winding bobbin, the range of height display is wide, and the range of height display is wide. Since the height was displayed by digital conversion, the practical limit was to display it in units of 1 tars, but in this embodiment, the error is small and it is possible to display the height down to 0.5 mm or less. In addition, the configuration is simple and inexpensive because the height can be displayed simply by detecting the amount of movement in the horizontal direction component of the link mechanism 3 with an encoder and processing the signal to obtain the amount of movement in the bed height direction. It can be done.

In addition, in the above embodiment, the case was described in which the moving direction was determined from the A-phase and B-phase pulse signals having different phases output from the encoder and the number of pulses in that direction was counted. By limiting , it is possible to eliminate the need for a counter or the like.

[Effects of the Invention] As described above, according to the present invention, the moving distance of the bed in the height direction can be measured with a simple configuration and without the need for any adjustment, and the height can be displayed with high accuracy. It is possible to provide a bed height display device that can.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the relationship between a frame and a link mechanism to which a bed height display device according to the present invention is applied, and FIG. 2(a)
and (b) are cross-sectional views taken along lines A-A and B-B in FIG. 1, FIG. 3 is a block circuit diagram showing an embodiment of the bed height display device of the present invention, and FIG. 1 is a block diagram mainly showing the t and '4 components of the arithmetic processing section in the same embodiment, and FIGS. 5 to 7 are diagrams for explaining the operation of the same embodiment. DESCRIPTION OF SYMBOLS 1... Fixed frame, 2... Moving frame, 3... Link mechanism, 4... Hydraulic cylinder, 5... Encoder, 11・・・・・・
・Encoder pulse input circuit, 12...Oscillator, 13...Up/down counter circuit, 14
... Frequency divider, 15 ... Arithmetic processing circuit,
16...Height detector, 17...Display device, 21a. 21b, 23a, '23b...Counter buffer, 22...RAM, 24...RO
M, 25...determination processing section, 26a, 26b...
...Display buffer, 27a, 27b...
Driver, 28...port selection section. Applicant's representative Patent attorney Takehiko Suzue Figure 1 (a) (b) Figure 2 b□D 0 77 ＋

Claims (1)

[Claims] A link that arranges a movable frame on which a bed top is placed parallel to a fixed frame, and connects these two frames to move the movable frame in a direction that is a combination of a horizontal component and a vertical component. The bed is provided with a mechanism and is configured to move the movable frame in the height direction by driving the link mechanism with a drive source. an encoder for detecting the amount of movement of a directional component; a direction determining means for determining the moving direction of the moving frame by discriminating the phase of a detection signal output from the encoder; and a direction determining means for determining the moving direction of the moving frame. a measuring means for measuring the amount of movement in that direction when determined; a storage section in which data corresponding to the amount of movement of the vertical component relative to the amount of movement of the horizontal component of the moving frame is stored in advance; a determining means for determining height display data corresponding to the amount of movement measured by the measuring means based on the stored data; and a display means for displaying the height based on the display data determined by the determining means. A bed height display device comprising: