JPS629860Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a patient chair for dentists equipped with a translation arm and an adjustment device for adjusting the height of the chair. is linked to a trestle supporting the seat of the chair.

Depending on the various treatment methods and the height of the patient, it is necessary to vary the height position of the upper part of the chair, which supports the seat of the chair, over a wide range. In addition, especially when treating a tall patient while sitting, it is necessary to be able to bring the patient's chair to a significantly lower position. Translation table arms have shown very good effectiveness for this purpose. since this allows the chair to be lowered to a minimum position determined essentially only by the structural height of the translation arm;
This is because the length of the platform arm in this case is significantly lower than in other known height adjustment devices used for the same purpose. Another advantage of the translation table arm is that it takes up less space to attach to the chair base.
This provides the therapist with a sufficiently large place to rest their feet. A hydraulic lifting device (piston-cylinder type) is used to adjust the height of the parallel movement table arm of such a patient chair. This is because only such a device can sufficiently carry the weight of a heavy chair with a patient on top, even with unfavorable leverage in the lowest position (pressures on the order of 1000 kilopounds or more), and because of its size. Because it is small, it can be stored in the narrow translation table arm (if the translation table arm is made large, it will be difficult for the doctor to easily approach the chair or patient, which will obstruct the doctor's work. ). However, it must be taken into account that a sufficiently leak-tight hydraulic drive is not available as an alternative. Over time, this oil leakage stains the bottom of the chair and the floor of the treatment room, so the oil-stained parts of the chair must be cleaned, but in some cases this can only be done at the factory, and from time to time. It takes many days and costs a lot of money.

The purpose of the present invention is to be able to generate the high pressure necessary for raising and lowering the chair in a patient chair of the type mentioned at the beginning, without significantly increasing the dimensions of the translation arm, and with ease of maintenance and inspection. I can do it,
To provide a patient chair for dentists that is free from stains due to oil leakage. In this case, consideration must also be given to reducing the manufacturing cost of the chair.

This purpose, according to the present invention, includes a translation table arm which is linked at one end to a side plate of the base and at the other end to a pedestal supporting the seat of the chair, and a spindle rod and a spindle nut disposed therein. and a seat height adjustment device, and the spindle rod is driven by an electric motor through a gear, and the translation table arms jointly form a box-shaped table arm. a drive motor is arranged at the base of the base outside the stand arm, and an intermediate shaft is provided for the transmission of drive torque from the motor to the spindle rod; has two drive rollers and is rotatably supported on an axis in line with the base-side link shaft of the platform arm, and is further provided with a transmission member in the form of a belt, chain, etc., which member is connected to the platform. The rotational torque of the drive motor is transmitted to the spindle rod in each tilted position of the arm, which is achieved by arranging the spindle rod and the spindle nut on diagonal link axes within the box-shaped trapezoidal arm.

According to the present invention, the use of a spindle device not only eliminates the drawbacks of the prior art devices mentioned above, but also provides the advantage of essentially requiring fewer components. Additionally, transportation and installation are simplified because the adjustment of the back and seat by means of translational table arms eliminates the need for interrelated drives required in conventional chairs. In other words, in the conventional mechanism, the oil sent from the oil pump installed on the base is not only supplied to the hydraulic system of the base arm but also to the hydraulic system of the lifting device installed at the top of the chair for adjusting the backrest. had to be sent to According to the present invention, such complexity is eliminated.

According to an advantageous embodiment of the invention, the spindle device can be constructed as a roller screw device or, in particular, as a ball spindle device. It is particularly advantageous to connect a self-braking gear upstream of the roller screw device. This is because it is possible to omit costly steps to stop the drive motor when the motor is stopped.
The drive motor can be mounted inside or outside the translation table arm. However, since the parallel translation table arm is box-shaped, there is a risk of forming a hollow body with large resonance characteristics that increases the noise of the motor, so it is recommended that the motor be installed outside the translation table arm. is advantageous. This eliminates the need for difficult soundproofing measures. By arranging the electric motor outside the base arm, there is also the advantage that the drive electric motor can be more easily accessed (replacement of brushes and V-belts).

Mounting the spindle or spindle nut on the diagonal link axis of the platform arm is advantageous, since undesired bending forces acting on the translation platform arm can be avoided.

You can choose to install the spindle and spindle nut above or below the link shaft, but if you install the gear on the link shaft on the base side, the transmission path for rotational torque from the electric motor to the spindle will be relatively short. Therefore, it is advantageous.

Furthermore, it is advantageous if the drive torque is transmitted from the drive motor to the spindle via an intermediate shaft, the axis of which coincides with one of the link axes on which the spindle arrangement of the translation arm is mounted.

The non-rotating part of the spindle device is divided into two parts, both parts are connected to each other via a connecting member that transmits rotational torque and are movable with respect to each other in the axial direction, and a safety switch is provided between the two parts, Preferably, the supply circuit of the drive motor is interrupted in response to tensile stresses occurring in the spindle arrangement.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a patient chair for a dentist with a base 1. FIG. A parallel movement table arm 2 is attached to the base 1 via a link shaft, and a pedestal 3 is provided at the free end of the arm. The pedestal 3 mainly supports the upper part of the chair, which consists of a backrest 4 and a seat 5. The backrest 4 can be tilted relative to the seat 5 about an axis 6, and the seat 5 can also be tilted relative to the pedestal 3 about an axis perpendicular to the longitudinal axis of the chair (not shown). ing. The three adjusting movements, namely the inclination of the backrest 4, the inclination of the seat 5 and the height adjustment of the upper part of the chair by means of the translation arm 2, are controlled by operating mechanisms 7 to 9 provided on the backrest 4. . The operating mechanisms 7 to 9 are arranged on the upper part of the backrest 4 and are attached so that they can be operated from behind or from above. The backrest 4 is made extremely thin, and even in a completely horizontal position,
The seated therapist is provided with sufficient freedom of leg movement. The operating mechanisms 7 to 9 are mounted deep into the backrest so that there are no protrusions.

The base 1 mainly consists of a base 11, and two upright side plates 12, 13 are provided on both front sides thereof, to which the translation table arm 2 is pivotably attached. The side plates 12, 13 are covered by removable cover plates 17, 18. The translation table arm 2 can be lowered from the illustrated position to the lowest position in which the arm is substantially horizontal (see FIG. 4). A footboard 14 is attached to the rear part of the base part 11 so as to be tiltable.
It cooperates with the opening/closing member installed in 1 so that when the footboard is stepped on, the drive mechanism for adjusting the translation table arm 2 is cut off. This structure helps the therapist's safety when something (the therapist's feet or the chair) inadvertently comes within the movement range of the pedestal 3 or the translation arm 2 during the lowering movement of the chair. .

As shown in FIG. 2, the base 1 has a welded structure consisting of a bottom plate 15 that can be fixed to the floor, and a box-shaped lid plate 1.
6 and side plates 1 welded to the bottom plate 15 on both sides thereof.
It is composed of 2 and 13. The bottom plate 15 and the cover plate 16 form the base of the base 1. Side plate 1
2, 13 are two halves welded together 19, 2
0, which are reinforced with spacers 21. The halves 19, 20 are made of sheet metal (drawn or pressed products). Bearing bushes for supporting the link shafts 22 and 24 of the translation table arms are welded inside the halves 19, 20. Lid plate 16
is made by cutting sheet metal and bending the corners.
The interior of the box thus formed is reinforced with a template 26 welded on the one hand to the lid plate 16 and on the other hand to the bottom plate 15 and placed parallel to the axial direction of the bottom plate. Templates are similarly made by the folding method. A gap is provided in the rear part of the cover plate 16,
A box with an open lid for accommodating two switches 28 and various electrical connection terminals 27 is formed in this box. Switch 28 is actuated by treadle 14 shown in FIG.

FIG. 3 shows a further embodiment of a welded base for supporting the translation table arm 2. In FIG. The base here consists of a bottom plate 30 and welded rectangular hollow rods 31, 32. The hollow rods 31, 32 form a stable and twist-free frame. A sheet metal cover 33 is installed on top of this frame. The side plates for supporting the parallel movement table arms are columns 34 to 37.
, which are likewise synthesized from hollow-body rods.

Both of the above-mentioned structures are extremely simple in terms of manufacturing technology, have a low transport weight and are also suitable for receiving side loads. In particular, the latter structure can be manufactured without the need for special tools.

FIG. 4 shows the state of the translation table arm 2 linked to the base 1 at its lowest position. The adjusting member of the translation table arm is shown partially cut away for better visibility. The translation table arm 2 mainly consists of two halves 40 and 41, including the upper half 40.
On the one hand, the side plates 12, 1 are connected by the link shaft 22.
3, and on the other hand, it is linked to the frame 3 via a link shaft 23. The lower half 41 of the stand arm is similarly connected to the side plates 12, 13 through a link shaft 24, and to the pedestal 3 through a link shaft 25. The adjustment of the translation arm 2 and the pedestal 3 relative to the chair upper part 4, 5 is effected by an electromechanical drive. This device consists of an electric motor 39, a gear 46 and a ball-swivel spindle device 47. The electric motor 39 is attached to the bottom plate 15 on the outside of the box-shaped translation table arm 2. Power is transmitted from the electric motor via a V-belt 48 to a roller 49, and then via the next V-belt 50 to a worm gear drive shaft 51. A rotating shaft 58 of a spindle device 47 is attached to the worm gear on the driven side. The electric motor 39 is fastened to a holding device 52 which is linked to the base plate 15 for tensioning the V-belt 48 . V-belt 4
8 is provided with the necessary tension of the belt by a tightening screw 53.

The gear 46 has a shaft 45 flanged thereto.
It is coupled to the link shaft 24 via. Since the spindle nut 54 is connected to the link shaft 23, the spindle drive mechanism engages the link shafts 23, 24 on the diagonals of the translation squares 22-25. The motor 39 is surrounded by a removable cover 57 for easy access.

FIG. 5 is a partially cutaway plan view of the parallel movement table arm. Roller 49 forms part of intermediate shaft 60, which can be easily removed from link shaft 24 when V-belts 48 and 50 are replaced. Details of the link shaft 24 are shown in FIG.

The lower half 41 of the parallel movement table arm 2 is connected to the side plate 1 by a bearing bolt 62 and a thrust bearing 63 on one side.
The other end is supported by the side plate 12 via a bearing bolt 64 and a thrust bearing 65. The intermediate shaft 60 is rotatably supported by two ball bearings 66, 67 on a plug-in shaft 68, which acts as a bearing shaft. As the plug-in shaft, an internal hexagonal screw is used, which on one side with its screw head connects the bearing bolt 6.
2, and the other end is screwed into a bearing bolt 64. The two bearing bolts 62, 64 are fixed against rotation by half-longitudinal screws 69, 70. By screwing the plug-in shaft 68 into the bearing bolt 64, the inner rings of the ball bearings 66, 67 are pressed against the ends of the bearing bolts 62, 64, thereby tensioning the bearing of the intermediate shaft.

Removal of the intermediate shaft for replacement of the V-belt is carried out by unscrewing the plug-in shaft 68 from the bolt 64 several times. The clamping screw 70 is then unscrewed and the bearing bolt 64 is easily knocked out by tapping the screw head of the plug-in shaft 68. By pulling the bearing bolt 64 away from the bolt 62, the tension in the bearing is released. The intermediate shaft 60 can be removed by completely unscrewing the insertion shaft 68.

Figure 7 shows one side of the link shaft 24 (bearing bolt 6).
4), the other is a partially cut away longitudinal sectional view of the spindle device 47 engaged with the link shaft 23. A gear 46 made of a commercially available part is screwed to the flange of the shaft 45. As is clear from the cutaway cross-sectional view, the internal structure of the spindle nut 54 includes a portion 71 including a portion 72 that includes the ball rotating portion, and a portion 72 that includes the switch 7.
3 and a portion 74 that accommodates the link shaft 23 and is connected to the link shaft 23. Both parts 72 and 74 are secured by three screws 75 attached around the periphery.
They are screwed together with some axial play 76 remaining. Since the entire spindle arrangement is normally under constant pressure, the three screws 75 serve exclusively to transmit torque from the rotating shaft 58 to the spindle parts 72, 74. When a tensile stress is applied to the spindle device, both parts 72 and 74 are pulled apart, and at the same time the actuating pin 77 is fixed to part 74 by leaving the opposite position 77' (part of 72). Switch 73 responds. Since the switch 73 is provided in the current circuit of the drive motor 39, the motor immediately stops when the switch is operated.

The pitch of the rotating shaft 58 is approximately 12 mm. Balls 78 are provided in the thread root, which are arranged in the region of part 72 as a kind of endless chain. When the spindle rotates, it moves within the ball screw valley. In one direction of rotation of the spindle, the ball exits the thread trough at point 79, enters the groove 80 at 72, exits again through the aperture 81 and enters the thread trough of the spindle. When the spindle rotates in the opposite direction, the ball travels in the opposite direction.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic diagram of the dental patient chair to which the present invention is applied, FIG. 2 is a detailed diagram of its base, FIG. 3 is a schematic diagram showing a different embodiment from FIG. 2, and FIG.
The figure is a partially cutaway side view of the lower part of the chair for explaining the parallel moving table arm according to the present invention, FIG. 5 is a partially cutaway plan view thereof, and FIG. 6 is a partially enlarged cross-sectional view of FIG. 5.
FIG. 7 is a detailed view of the spindle device provided on the translation table arm. 1... Base, 2... Parallel movement table arm, 22-25
... Link shaft, 39 ... Electric motor, 47 ... Spindle device, 60 ... Intermediate shaft, 73 ... Safety switch.

Claims (1)

[Scope of utility model registration request] A parallel movement table arm 2 whose one end is linked to the side plates 12 and 13 of the base 1 and the other end is linked to the pedestal 3 supporting the seat 5 of the chair, and a spindle rod 5 disposed therein.
8 and a seat height adjustment device 47 with a spindle nut 54, the spindle rod 58 being driven by an electric motor 39 via a gear 46, The arm 2 consists of two halves 40, 41 which together form a box-shaped platform arm, a drive motor 39 is arranged on the base 11 of the base 1 outside said platform arm 2, said motor 39 An intermediate shaft 60 is provided for transmitting the driving torque from the spindle rod 58 to the spindle rod 58, and the intermediate shaft is provided with two driving rollers 49 and rotates on a shaft 68 that is in line with the base-side link shaft 24 of the base arm 2. A transmission member in the form of a belt, chain or the like 48, 50 is also provided, which transmits the rotational torque of the drive motor 39 to the spindle rod 58 in each inclined position of the platform arm 2. A dental patient chair with a translation table arm, characterized in that the spindle rod 58 and the spindle nut 54 are arranged on diagonal link axes in the box-shaped table arm 2.