JP6308367B2 - Dental treatment chair - Google Patents

Description

  The present invention relates to a dental treatment chair, and more particularly to a dental treatment chair that reduces the occurrence of an impact when adjusting the posture of each part of the chair according to the weight value of a patient.

  The dental treatment chair can be adjusted in various postures such as raising and lowering the chair and raising and lowering the backrest so that the operator can easily treat the patient. When adjusting the posture of the dental treatment chair, particularly when driving and stopping, there may be a shock due to a sudden change in the adjusted part of the chair, giving the patient a sense of fear or lowering the waist. It may cause pain for patients with cervical spine disease.

  For this reason, for example, in Patent Document 1, in a dental treatment chair having a controlled movable part such as a seat seat or a backboard seat, the acceleration and / or deceleration of the controlled movable part is started and / or stopped. It is disclosed to provide a control means for controlling the moving speed so as to reach a predetermined maximum speed and / or zero by gradually increasing the speed and then gradually decreasing the speed. It is disclosed that the control is performed by opening / closing control of a hydraulic valve disposed in the middle of a hydraulic oil supply line of the hydraulic mechanism.

  Further, in Patent Document 2, the number of rotations of a hydraulic pump driving motor that drives a lifting cylinder of a chair and a raising / lowering cylinder of a backrest is controlled based on an acceleration / deceleration time setting input in advance to an inverter. A chair is disclosed that gradually accelerates from a low speed at the start and gradually decreases the rotational speed at the end of driving, and is intended to eliminate the impact caused by sudden fluctuations in driving at the start and end of driving.

JP 2003-325595 A JP 2008-142455 A

In the chairs disclosed in Patent Documents 1 and 2, basically, the amount of hydraulic oil supplied to the hydraulic cylinder is gradually increased or decreased by opening / closing control of the hydraulic valve or rotation speed control of the hydraulic pump. This reduces the occurrence of shocks at start and stop. However, the chairs disclosed in Patent Documents 1 and 2 do not consider the weight value of the patient, and the raising and lowering of the seat and the raising and lowering of the back plate are performed by the same control method .

  The present invention has been made in view of these circumstances, and by automatically adjusting the magnitude of shock absorption of the hydraulic circuit according to the weight value of the patient, the difference in impact due to the difference in weight of the patient is reduced. The object is to reduce the pulsation of the hydraulic circuit.

In order to solve the above problems, the invention of claim 1 detects a load applied to the seating portion in a dental treatment chair that adjusts the posture of the seating portion by a hydraulic circuit having a hydraulic cylinder, a hydraulic pump, and a control valve. And a hydraulic accumulator provided with a piston-type accumulator, and a load applied to the piston of the piston-type accumulator is changed in accordance with an output of the load sensor .

The invention of claim 2 is characterized in that, in the invention of claim 1, the load applied to the piston is increased as the amount of change in the load detected by the load sensor is larger.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the accumulator is formed of a cylinder having a piston loaded with a spring therein, and the change of the load applied to the piston is a compression of the spring. This is performed by changing the amount.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the accumulator is provided between the hydraulic cylinder and the control valve.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the hydraulic cylinder is a hydraulic cylinder for raising and lowering a contour seat of the dental treatment chair or for raising and lowering a backrest. This is a hydraulic cylinder.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the discharge amount per hour of the hydraulic pump is further changed according to the amount of change in the load detected by the load sensor. It is a feature.

  According to the present invention, by adjusting the magnitude of shock absorption of the hydraulic circuit according to the weight value of the patient, it is possible to eliminate the difference in impact due to the weight difference of the patient and reduce pulsation of the hydraulic circuit, It can prevent fear and pain to the patient.

It is a schematic block diagram for demonstrating an example of the dental treatment chair with which this invention is applied. It is a block diagram which shows an example of the hydraulic circuit of the dental treatment chair which concerns on this invention. It is a figure for demonstrating an example of the functional block for controlling the hydraulic circuit of the dental treatment chair which concerns on this invention. It is a figure for demonstrating an example of the operation | movement flow of the dental treatment chair which concerns on this invention. It is a figure for demonstrating the other example of the hydraulic circuit of the dental treatment chair which concerns on this invention.

  Hereinafter, preferred embodiments according to a dental treatment chair of the present invention will be described with reference to the drawings. In the following description, the configurations denoted by the same reference numerals in different drawings are the same, and the description thereof may be omitted.

  FIG. 1 is a schematic configuration diagram for explaining an example of a dental treatment chair to which the present invention is applied. The dental treatment chair 1 includes a base 2 and a seating portion including a contour seat (seat seat) 3 provided on the base 2, a backrest 4, a legrest 5, and the like. The base 2 is provided with a lifting cylinder 10 between the grounding portion, and the base 2 is lifted by pulling out the piston rod 10c of the lifting cylinder 10 from the lifting cylinder 10 to lift the piston rod 10c. The base 2 is lowered by being drawn into the cylinder 10.

  The backrest 4 is provided so as to be rotatable about the shaft portion 8 with respect to the base 2, and the angle with respect to the contour seat 3 can be changed. In this embodiment, the raising / lowering cylinder 20 is fixed to the base 2, and the link 21 is provided between the shaft portion 6 on the lower side of the backrest and the shaft portion 7 provided on the piston rod 20 c of the raising / lowering cylinder 20. Is provided. The backrest 4 is laid by pulling out the piston rod 20c of the raising / lowering cylinder 20 from the raising / lowering cylinder 20, and the backrest 4 is raised by drawing the piston rod 20c into the raising / lowering cylinder 20. The raising / lowering cylinder 10 and the raising / lowering cylinder 20 correspond to the hydraulic cylinder of this invention.

  Between the base 2 and the lifting cylinder 10, a load sensor 22 for measuring the mass of the seating portion including the base 2 and above the base 2 is provided. For example, a load cell that converts a mass into an electrical signal using a strain gauge can be used as the load sensor 22. As will be described later, the weight value of the patient is calculated from the load change before and after the patient sits on the dental treatment chair. Various types of load sensors 22 can be used.

  The operator can move up and down the seats such as the base 2, the contour seat 3, the backrest 4 and the legrest 5 or raise and lower the backrest 4 by operating an operation panel (not shown). The surgeon can perform a treatment or the like by moving each part of the dental treatment chair 1 up and down to make the patient easy to treat. In the present embodiment, the vertical movement of the seating portion on which the weight of the patient is mainly applied and the backrest 4 being tilted will be described as the adjustment part of the dental treatment chair 1, but other parts of the dental treatment chair, for example, An anvil or a footrest may be provided so that the posture can be adjusted.

  FIG. 2 is a block diagram showing an example of a hydraulic circuit of the dental treatment chair according to the present invention. A hydraulic circuit 100 shown in FIG. 2 is for driving the lifting cylinder 10, and includes a controller 30, a hydraulic pump 40, a pump drive motor 41, an oil tank 42, control valves 51 and 52, and an accumulator 60. Yes. The controller 30 is for performing the start and stop of the hydraulic pump 40 by the pump drive motor 41, the opening and closing operation of the control valves 51 and 52, and the like according to the operation of the operator from an operation panel (not shown).

  In this embodiment, the elevating cylinder 10 is configured as a single-acting cylinder, and a piston 10b is provided in the cylinder tube 10a, and a piston rod 10c is provided on the piston 10b. By supplying hydraulic oil to a cylinder chamber 10d formed by the cylinder tube 10a and the piston 10b, the piston rod 10c is pulled out from the cylinder tube 10a, and the cylinder tube 10a is raised. On the other hand, the lowering of the cylinder tube 10a is performed by discharging hydraulic oil from the cylinder chamber 10d.

  The hydraulic circuit 100 includes a hydraulic pump 40 and an oil tank 42. The hydraulic pump 40 is driven by a pump drive motor 41 and supplies hydraulic oil from an oil tank 42 to the lifting cylinder 10. By changing the number of rotations of the pump drive motor 41, the amount of hydraulic oil discharged from the hydraulic pump 40 can be changed. The hydraulic pump 40 and the pump drive motor 41 may be constituted by an electric pump in which these are integrated. The oil tank 42 stores the hydraulic oil discharged from the elevating cylinder 10 and supplies it again to the hydraulic pump.

  Control valves 51 and 52 are provided between the hydraulic pump 40 and the lifting cylinder 10. In this embodiment, the control valves 51 and 52 are two-port single-acting normally closed solenoid valves, which are closed when not energized and opened when energized. The control valve is not limited to a 2-port single-acting normally closed solenoid valve, and other control valves may be used, such as a 2-port single-acting normally-open solenoid valve. The control valve 51 is a control valve for supplying hydraulic oil from the hydraulic pump 40 to the cylinder chamber 10 d of the lifting cylinder 10, and the control valve 52 supplies hydraulic oil from the cylinder chamber 10 d of the lifting cylinder 10 to the oil tank 42. It is a control valve for discharging.

  The control valve 51 and the control valve 52 are not opened simultaneously, and the position of the seating portion can be maintained at an arbitrary position by maintaining both the control valve 51 and the control valve 52 in the closed state. it can. When raising the seating portion, the control valve 51 is opened and the control valve 52 is closed, so that hydraulic oil is supplied to the cylinder chamber 10d and the cylinder tube 10a is raised. When lowering the seating portion, the control valve 51 is closed and the control valve 52 is opened, so that the weight of the patient and the seating portion causes the weight to act from the cylinder chamber 10d via the control valve 52. Oil is discharged to the oil tank 42.

  In the present invention, an accumulator 60 is disposed between the cylinder chamber 10d of the lifting cylinder 10 and the control valves 51 and 52 in order to reduce the impact during the lifting and lowering operation of the chair. The accumulator 60 of this embodiment is a piston type accumulator, and includes a cylinder tube 61, a piston 62, and a spring load adjusting piston 63. A spring 64 is provided between the piston 62 and the spring load adjusting piston 63, and the piston 62 is provided to be movable in the cylinder tube 61a in a state where a spring load is applied. The cylinder tube 61 of the accumulator 60 corresponds to the cylinder of the accumulator of the present invention.

  The spring load adjusting piston 63 is provided with an adjusting shaft 65 with a screw that can be inserted and removed in a state in which rotation with respect to the cylinder tube 61 is prevented. The adjusting shaft 65 is connected to a gear 66 having a screw on the inner periphery. It is inserted. The adjustment shaft 65 can be inserted into and removed from the cylinder tube 61 by rotating the gear 66 forward and backward by the spring adjustment motor 67. The adjustment shaft 65 compresses the spring 64 by being pushed into the cylinder tube 61, and the repulsive force of the spring 64 is applied to the piston 62. For this reason, the amount of compression of the spring 64 is changed by forward / reverse rotation of the spring adjustment motor 67 so that the load applied to the piston 62 can be adjusted. As the spring adjustment motor 67, a stepping motor that can easily control the rotation direction and the rotation speed can be used.

  A cylinder chamber 68 formed by the cylinder tube 61 and the piston 62 is provided with an input / output port for hydraulic oil. This input / output port may be a common port. Then, the piston 62 stops at a position where the hydraulic oil pressure in the cylinder chamber 68 and the repulsive force of the spring 54 are balanced. The spring load adjusting piston 63 is configured as a piston in the present embodiment, but may not be a piston as long as it is a member that can compress and extend the spring 64. Further, the adjustment shaft 65 is also provided with a screw, but any other mechanism may be used as long as the mechanism can compress and extend the spring from the outside.

  If the control valves 51 and 52 of the hydraulic circuit 100 are rapidly closed or a sudden change in load occurs, impact pressure is generated in the piping of the hydraulic circuit, causing noise and damage to piping equipment. However, in this embodiment, since the capacity of the hydraulic oil in the cylinder chamber 68 of the accumulator 60 can be changed, the impact due to the opening and closing of the control valves 51 and 52 can be reduced. In addition, the hydraulic oil discharged from the hydraulic pump contains pulsation due to the structure of the pump, which causes noise and vibration, which makes the hydraulic circuit operation unstable and causes equipment damage. The accumulator 60 can attenuate the pulsation of the hydraulic oil.

  That is, in the state where the piston 62 is stationary at a position where the pressure of the hydraulic oil in the cylinder chamber 68 and the repulsive force of the spring 54 are balanced, if an impact or pulsation due to a pressure change occurs on the upstream side of the hydraulic circuit, the pressure The piston 62 moves in the axial direction of the cylinder tube 61 in accordance with the magnitude of the change, thereby causing a change in the volume of hydraulic oil in the cylinder chamber 68. This volume change absorbs shocks and pulsations and can prevent the pressure change from propagating downstream of the accumulator 60.

  For this reason, the accumulator 60 may be arranged directly downstream of the hydraulic pump 40. However, in order to reduce the pressure fluctuation in the cylinder chamber 10d of the lifting cylinder 10, the control valves 51, 52 and the cylinder chamber 10d It is desirable to provide it in between.

  Further, in the present invention, the characteristics of the accumulator are changed according to the weight value of the patient, and this point will be described below. FIG. 3 is a diagram for explaining an example of functional blocks for controlling the hydraulic circuit of the dental treatment chair according to the present invention.

  The controller 30 of the hydraulic circuit 100 includes an operation reception unit 31, a load value calculation unit 32, a spring adjustment amount calculation unit 33, a spring adjustment motor rotation number setting unit 34, a pump drive motor rotation number setting unit 35, and an operation output unit. 36. The functions of the controller 30 can be realized by executing a microcomputer having a CPU, a ROM, and a RAM (not shown) and a control program stored in advance in the ROM.

  The operation reception unit 31 receives a command signal for posture adjustment of each part of the dental treatment chair 1 from the operator by operating the operation panel 23, and commands the posture adjustment to the operation output unit 36 so as to perform a predetermined operation. A signal is being transmitted. The load value calculation unit 32 receives an output signal from the load sensor 22 and calculates a load value (mass), and outputs the difference when the load value changes. Thereby, the patient's weight value is calculated from the load change when the patient sits on the dental treatment chair 1.

  The spring adjustment amount calculation unit 33 is for calculating the adjustment amount (compression amount) of the spring 64 of the accumulator 60 according to the weight value of the patient. The heavier the patient's weight, the shorter the spring 64 is and the lighter the patient is. The spring 64 is extended. Since the adjustment amount of the spring 64 with respect to the patient's body weight value is also affected by the weight of the upper part from the base 2 of the dental treatment chair, the processing speed is increased by converting the data into a look-up table in advance. be able to. The spring adjustment motor rotation speed setting unit 34 is for setting the rotation direction and rotation speed of the spring adjustment motor 67 in accordance with the adjustment amount of the spring 64 of the accumulator 60. In this embodiment, the spring adjustment amount calculation unit 33 is provided. However, the rotation direction and the number of rotations of the spring adjustment motor 67 may be directly obtained from the patient's weight value obtained by the load value calculation unit 32.

  The accumulator 60 is provided with a sensor (not shown) for detecting the position of the spring load adjusting piston 63 or the pulling amount of the adjusting shaft 65. Based on the detection value from the sensor, the accumulator 60 is used for dental treatment. When the patient is not on the treatment chair 1, the spring adjustment motor 67 is rotated in advance so that the spring load adjustment piston 63 comes to a predetermined position as an initial position. Similarly, when the patient is not on the dental treatment chair 1, the lifting cylinder 10 is driven so that the height of the dental treatment chair 1 is also at the initial position.

  The pump drive motor rotation number setting unit 35 changes the discharge amount per hour of the hydraulic oil from the hydraulic pump 40 by setting the rotation number of the pump drive motor 41 based on a command from the operation panel 23. This is for setting the operating speed of the hydraulic piston to a predetermined speed. For example, when the surgeon wants to quickly adjust the posture of each part of the dental treatment chair 1, by operating the operation panel 23, the rotational speed (rotational speed) of the pump drive motor 41 is increased. Thus, the operation of the hydraulic piston can be accelerated. Or, for patients who are afraid of posture adjustment speed too fast, patients with lower back, cervical vertebral disease, patients who are prone to anemia, etc. , Reduce the burden on the cervical spine, and prevent anemia.

  Furthermore, for example, even in the case of a generally light patient such as a child, the anxiety given to the patient may be reduced by slowly adjusting the posture of the dental treatment chair 1. For this reason, the pump drive motor rotation number setting unit 35 may be configured to receive the patient weight value signal from the load value calculation unit 32 and set the rotation number of the pump drive motor 41.

  The operation output unit 36 receives an operation signal from the operation receiving unit 31, a rotation direction and rotation number signal of the spring adjustment motor 67 from the spring adjustment motor rotation number setting unit 34, and a pump drive motor rotation number setting unit 35. In response to the rotational speed signal of the pump drive motor 41, the control valves 51 and 52, the spring adjustment motor 67, and the pump drive motor 41 are output with signals for operating them. The control valves 51 and 52, the spring adjustment motor 67, and the pump drive motor 41 each perform a predetermined operation based on a signal from the operation output unit 36 of the controller 30.

Next, the operation of the dental treatment chair 1 will be described. FIG. 4 is a diagram for explaining an example of the operation flow of the dental treatment chair according to the present invention.
First, in the initial state, the load value calculation unit 32 of the controller 30 watches the output signal from the load sensor 22, and determines whether there is a load change due to a change in the output signal from the load sensor 22 (step). S1). Here, the initial state means a state in which the posture of the dental treatment chair is adjusted to a predetermined initial position, and the adjustment shaft 65 of the accumulator is also in a predetermined position. If there is no load change in step S1 (in the case of NO), watching is continued, and if there is a load change (in the case of YES), the load change amount, that is, the weight value of the patient is calculated and calculated. The changed amount is output to the spring adjustment amount calculation unit 33 (step S2).

  Note that the first load change in step S1 is when the patient is on the dental treatment chair 1, and at this time, the control valves 51 and 52 of the hydraulic circuit 100 are both closed. For this reason, the pressure corresponding to the weight of the patient is transmitted to the cylinder chamber 68 of the accumulator via the hydraulic oil in the cylinder chamber 10d of the elevating cylinder 10, and the piston 62 of the accumulator 60 is subjected to the pressure due to the body weight and the repulsive force of the spring 64. Will move downward until they equilibrate. In addition, due to this influence, the base 2 of the dental treatment chair 1 also moves slightly downward.

  Next, the spring adjustment amount calculation unit 33 calculates the adjustment amount of the spring 64 according to the load change amount input from the load value calculation unit 32, and uses the calculated adjustment amount as the spring adjustment motor rotation number setting unit 34. (Step S3). The spring adjustment motor rotation speed setting unit 34 sets the rotation direction and rotation speed of the spring adjustment motor 67 according to the adjustment amount input from the spring adjustment amount calculation unit 33, and outputs the set value to the operation output unit 36. (Step S4). Further, the operation output unit 36 drives the spring adjustment motor 67 based on the set values of the rotation direction and the rotation speed of the spring adjustment motor 67 (step S5). Thereby, the spring 64 is compressed and extended by a predetermined amount, and the load applied to the piston 62 is adjusted.

  The rotation direction of the spring adjusting motor 67 changes depending on the initial position of the adjusting shaft 65, and the initial position of the adjusting shaft 65, that is, the initial position of the spring load adjusting piston 63 is set sufficiently downward. Thus, the load applied to the piston 62 may be adjusted by rotating the spring adjustment motor 67 in one direction.

  Next, the process proceeds to step S <b> 6, and the operation reception unit 31 of the controller 30 determines whether or not there is an operation input from the operation panel 23. When there is no operation input (in the case of NO), it waits, and when there is an operation input (in the case of YES), it is determined whether or not it is an end operation (step S7). If the operation is not an end operation (NO in step S7), the pump drive motor speed setting unit 35 determines the pump drive motor 41 according to the operation signal from the operation panel or the weight value from the load value calculation unit 32. The number of rotations per hour (rotation speed) is set (step S8).

  After step S8, the process proceeds to step S9, where the operation output unit 36 opens and closes the control valve according to the operation for posture adjustment, and drives the pump drive motor 41 so as to achieve the rotational speed per time set in step S8. I do. In addition, as a case where operation | movement of step S9 is performed initially, it will become operation | movement which raises the dental treatment chair 1 normally. When step S9 ends, the process returns to step S6 and waits for the next operation input.

  In step S7, when the operation input is an end operation (in the case of YES), the process proceeds to step S10, and the operation output unit 36 drives the control valves 51 and 52, the pump drive motor 41, and the spring adjustment motor 67. Then, after returning the dental treatment chair 1 to the initial position, the operation is finished. Here, the ending operation is an operation after the normal treatment ends and the patient gets out of the dental treatment chair 1.

  As described above, the embodiment of the present invention has been described with respect to the lifting cylinder 10 of the dental treatment chair 1, but the present invention is also applicable to the raising / lowering cylinder 20 of the backrest 4. FIG. 5 is a view for explaining another example of the hydraulic circuit of the dental treatment chair according to the present invention. The hydraulic circuit 100 shown in FIG. 5 is for driving the raising / lowering cylinder 20. , Controller 30, hydraulic pump 40, pump drive motor 41, oil tank 42, control valves 53 to 56, and accumulators 60 ', 60 ". Controller 30, hydraulic pump 40, hydraulic pump drive motor 41, As for the oil tank 42, since the oil tank 100 shown in FIG. 2 is commonly used, the description thereof is omitted.

  The raising / lowering cylinder 20 is configured as a double acting cylinder, and a piston 20b is provided in the cylinder tube 20a, and a piston rod 20c is provided on the piston 20b. The raising / lowering cylinder 20 draws the piston rod 20c from the cylinder tube 20a by supplying the hydraulic oil to the cylinder chamber 20d formed by the cylinder tube 20a and the piston 20b and discharging the hydraulic oil from the cylinder chamber 20e on the piston rod side. The piston rod 20c is drawn into the cylinder tube 20a by supplying the hydraulic oil to the cylinder chamber 20e and discharging the hydraulic oil from the cylinder chamber 20d.

  The control valve 53 is a control valve for supplying hydraulic oil from the hydraulic pump 40 to the cylinder chamber 20e of the raising / lowering cylinder 20, and the control valve 54 supplies hydraulic oil from the cylinder chamber 20e of the raising / lowering cylinder 20 to an oil tank. This is a control valve for discharging the gas. Further, the control valve 55 is a control valve for supplying hydraulic oil from the hydraulic pump 40 to the cylinder chamber 20 d of the raising / lowering cylinder 20, and the control valve 56 supplies hydraulic oil from the cylinder chamber 20 d of the raising / lowering cylinder 20. It is a control valve for discharging to the oil tank. In this embodiment, the control valves 53 to 56 are 2-port single-acting normally closed solenoid valves, as in the control valves 51 and 52 of the hydraulic circuit shown in FIG. Valves or other control valves may be used.

  The control valve 53 and the control valve 54, and the control valve 55 and the control valve 56 are not simultaneously opened, and when the posture of the backrest 4 is maintained, all of the control valves 53 to 56 are used. The valve is kept closed. When raising the backrest 4, by opening the control valve 53 and the control valve 56, the hydraulic oil is supplied to the cylinder chamber 20e and the hydraulic oil is discharged from the cylinder chamber 20d. The piston 20b is moved in the retracting direction. During this time, the control valves 54 and 55 are kept closed.

  When tilting the backrest 4, the control valve 55 and the control valve 54 are opened to supply the hydraulic oil to the cylinder chamber 20d and discharge the hydraulic oil from the cylinder chamber 20e. The piston 20b is moved in the direction to pull out 20c. During this time, the control valves 53 and 56 are kept closed. When the posture adjustment of the dental treatment chair 1 is not performed, that is, when the position of the seating portion is not moved, the control valves 51 to 56 are closed, and the hydraulic pump 40 is not driven.

  An accumulator is provided between the cylinder chamber 20e of the raising / lowering cylinder 20 and the control valves 53 and 54 in order to alleviate the impact associated with the operation of the backrest 4 when starting and stopping during the raising / lowering operation of the backrest 4. 60 'is disposed between the cylinder chamber 20d of the raising / lowering cylinder 20 and the control valves 55 and 56, respectively. The accumulators 60' and 60 "are arranged in the hydraulic circuit 100 shown in FIG. This is a piston type accumulator having the same configuration as the accumulator 60, and by driving the respective spring adjusting motors 67 ′ and 67 ″, the load applied to the respective pistons 62 ′ and 62 ″ can be adjusted.

  Since the load applied to each of the pistons 62 ′ and 62 ″ is adjusted according to the weight value of the patient is the same as that of the accumulator 60 provided in the lifting cylinder 10, the description thereof is omitted. Thus, by automatically adjusting the shock absorption magnitude of the hydraulic circuit according to the weight value of the patient, the impact when the backrest 4 is raised and lowered can be reduced, and the hydraulic circuit can reduce the difference in impact due to the patient weight difference. Pulsation can be reduced.

  Note that a second load sensor different from the load sensor 22 is provided on the backrest 4, and the load applied to the pistons 62 ′ and 62 ″ is adjusted based on the load value detected by the second load sensor. In this case, since the load applied to the second load sensor changes in accordance with the raising / lowering operation of the backrest 4, the load applied to the pistons 62 ′ and 62 ″ is adjusted accordingly. . For example, when the backrest 4 is tilted, the load applied to the second load sensor increases as the inclination angle of the backrest 4 increases, and accordingly, the load applied to the piston 62 ″ of the accumulator 60 ″ is increased accordingly. It will be. Further, when the backrest 4 is tilted, the operation speed of the backrest 4 is set by setting the number of rotations per hour of the pump drive motor 41 according to the operation signal from the operation panel or the patient's weight value. It may be changed.

DESCRIPTION OF SYMBOLS 1 ... Dental treatment chair, 2 ... Base, 3 ... Contour seat, 4 ... Backrest, 5 ... Leg rest, 6, 7, 8 ... Shaft part, 10 ... Lifting cylinder, 20 ... Lifting cylinder, 10a , 20a ... cylinder tube, 10b, 20b ... piston, 10c, 20c ... piston rod, 10d, 20d, 20e ... cylinder chamber, 21 ... link, 22 ... load sensor, 23 ... operation panel, 30 ... controller, 31 ... operation acceptance , 32... Load value calculation unit, 33... Spring adjustment amount calculation unit, 34... Spring adjustment motor rotation number setting unit, 35... Pump drive motor rotation number setting unit, 36. ... Pump drive motor, 42 ... Oil tank, 51-56 ... Control valve, 60, 60 ', 60 "... Accumulator, 61 ... Cylinder tube, 62, 62', 62" ... Piste , 63 ... spring load adjusting piston, 64, 64 ', 64 "... spring, 65 ... adjustment shaft, 66 ... gear, 67, 67', 67" ... spring adjusting motor, 100 ... hydraulic circuit.

Claims (6)

In a dental treatment chair that adjusts the posture of a seating portion by a hydraulic circuit having a hydraulic cylinder, a hydraulic pump, and a control valve, a weight sensor that detects a load applied to the seating portion, and a piston type accumulator provided in the hydraulic circuit, A dental treatment chair, wherein a load applied to a piston of the piston type accumulator is changed according to an output of the load sensor . The dental treatment chair according to claim 1 , wherein the load applied to the piston is increased as the amount of change in the load detected by the load sensor is larger.   The said accumulator is comprised from the cylinder which has a piston loaded with the spring inside, The change which concerns on the said piston is performed by the change of the compression amount of the said spring, The Claim 1 or 2 characterized by the above-mentioned. Dental treatment chair.   The dental treatment chair according to any one of claims 1 to 3, wherein the accumulator is provided between the hydraulic cylinder and the control valve.   5. The hydraulic cylinder according to claim 1, wherein the hydraulic cylinder is a hydraulic cylinder for raising and lowering a contour seat of the dental treatment chair or a hydraulic cylinder for raising and lowering a backrest. Dental treatment chair.   The dental treatment chair according to any one of claims 1 to 5, wherein a discharge amount per hour of the hydraulic pump is further changed according to a change amount of a load detected by the load sensor.

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