FI82183C - HYDRAULISK STYRANORDNING FOER BEHANDLINGSSTOL. - Google Patents

Description

1 82183

Nursing chair hydraulic control unit

The invention relates to a hydraulic control device for a treatment chair comprising a plurality of mutually adjustable chair parts, comprising a guide circuit fed by a pump, cylinder-piston units interposed between the chair parts, line connections for cylinder-piston units as well as supply lines in parallel, control valves are arranged in the return lines for controlling the piston units of the cylinder-10, and one non-return valve in each case for the supply lines, whereby the cylinder-piston units can be pressurized under pressure to prevent movements.

A control device of the above-mentioned quality is described 15 and disclosed in DE-PS 3 105 979. In this known control device, slowly closing and opening control valves are arranged in the supply lines and return lines of the cylinder-piston units in order to achieve the desired throttled supply. These are control valves 20 comprising an electric motor drive for opening and closing said control valve.

This known control device is very expensive. This is due not only to the relatively complex nature of the slowly closing and opening actuators and the increased control costs, but also to the fact that it is designed for single-acting cylinder-piston units. In the case where a known control device is used for a modern treatment chair in which a number of mutually adjustable parts of the chair-30 have to be actively controlled in both control directions, a large number of relatively complex control valves is necessary, resulting in not only large and expensive structure but also large space requirements.

DE-PS 1 179 330 discloses a corresponding device with supply channels in which non-return valves are arranged.

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DE-PS 2 612 801 further discloses a device with double-acting hydraulic cylinder-piston units for adjusting the support parts of a patient table comparable to a treatment chair.

The invention, which is characterized in the characterizing part of claim 1, solves the object of providing a control device of the quality mentioned at the beginning which, when reducing control valves, does not require a large space and is not so complicated 10 and which can therefore be manufactured more cost-effectively.

The substantial advantage achieved by the invention can be seen in particular in that when using double-acting cylinder-piston units a smaller number of 15 specially controllable control valves has to be fitted, as a result of which the desired simplification and reduced space requirement are achieved. The embodiment according to the invention makes it possible to fit the control valves only to the sections of the return lines. In contrast, in the prior art, control valves are also necessary in the sections of the supply lines.

The control device according to the invention is available for treatment chairs in which several chair parts have to be adjusted relative to each other, as is particularly the case with a dental treatment chair. It is also suitable for other medical nursing chairs, such as examination and procedure equipment, and hairdresser's chairs.

Further preferred embodiments of the invention are set out in the dependent claims and described below. Embodiments of the invention 30 are shown by way of example in the drawing.

Fig. 1 shows a dental treatment chair shaped according to the invention in a side view comprising several cylinder-piston units for adjusting chair parts, Fig. 2 shows a hydraulic control diagram of a control device 35 according to the invention, Fig. 3 shows a section control valve in the operating position, 5 Figures 5 and 6 show the throttled supply of the cylinder-piston units in connection with the operation diagrams.

The dental treatment chair, generally indicated by the number 1 in Fig. 1, consists of a height-adjustable lower part 2 of the chair and a multi-proportionally adjustable upper part 3 formed by a seat 4, a backrest 5 and a headrest 6, which are adjustable relative to each other and fixed to each adjusting position.

Arranged in the cavity of the lower part 2 of the chair is a parallelogram mechanism 7 for adjusting the height of the lower part 15 of the chair, which rests on the bottom of the lower part 2 and engages its cover plate 8, the actuator being a single-acting cylinder-piston unit 9 2 to the body or to the lower lifting arm 11 of the parallelogram mechanism 7 20 and which with its piston rod 12 engages the upper lifting arm 13.

In addition to the cavity of the lower part 2 of the chair, other parts of the control device of the treatment chair 1 to be explained, namely the motor-pump unit 14, the hydraulic tank 15 and 25, the control group still to be explained are arranged.

The upper part 3 of the chair is adjustable with the lower part 2 of the chair horizontally along the seat direction. For this purpose, a cylinder-piston unit 17 fitted in the cavity of the seat 4 is used, which is articulated to the bearing eyes 18, 19 of the seat 4 of the lower part 2 and 30 of the chair.

The inclination of the backrest 5 can be changed and adjusted by a double-acting cylinder-piston unit 21, which is likewise located in the cavity of the seat 4 and articulated between the bearing eyes 22, 23 of the seat 4 and the backrest 5. The 5 tilt axles of the backrest are marked with the number 20.

4 82183 The headrest 6 is first optionally raised and lowered and secondly attached to the backrest 5 which can be tilted about the tilting axis 24. To raise and lower the headrest 6, a double-acting cylinder-5 rib piston unit 25 is used, which is fitted in the cavity of the backrest 5 and articulated to the bearing eyes. The inclination of the headrest 6 is variable and adjustable by a double-acting cylinder-piston unit 28 articulated to the bearing eyes 29, 30 of the parts adjustable relative to each other.

The control device shown in Fig. 2 comprises a hydraulic circuit having a supply line, generally designated 31, and a return line, generally designated 32, which are supplied by the motor-pump unit 14 to supply the cylinder-piston units 9, 17, 21, 25 and 28. The supply and return are controlled by a pre-controlled control valve 16 which, in its rest position, where it is loaded by the spring 33, closes the supply line 31 and the return line 32 and in its pre-controlled operating position opens the passage of the supply and return lines 31, 32. The arrangement is made so that in the rest position the passage throttled by the throttle 34 is located upstream of the supply line portion 35 from the pilot valve 16 and downstream of the return line portion 36 from the pilot valve 16, which branches into a single-acting cylinder-branch unit 9 and a return line branch 38 connected to the double-acting cylinder-piston units 17, 21, 25, 28.

From the supply line section 39 downstream of the pilot valve 16, a section 41 of the supply line 30 branches to the pressure space 42 of the single-acting cylinder-piston unit 9, which has a 2/2-way valve 43 in the flow direction and a non-return valve 44 the portion 41 is connected to a branch 35 37 of the return line, in which the direction of the return flow is arranged in succession

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5 82183 non-return valve 45, adjustable throttle 46 and 2/2-way valve 47.

Of the double-acting cylinder-piston units 17, 21, 25, 28, the pressure chambers 48 and 49 are connected to both the supply line 31 and the return line 32.

For this purpose, the sections 51-54 and 55-58 of the supply lines and the sections 59-66 of the return lines are arranged, of which always two interconnected ones are connected to each other and via the line section 67-74, which serves both the supply and the return. to the pressure conditions 48 or 49 of the cylinder-piston units 17, 21, 25, 28. The supply line 31 is branched at 75. The supply line sections 51 to 54 leave the supply line branch indicated by 76, while the line 55-58 of the supply line 15 leaves 77 important supply line branches. A check valve 78 is arranged in each section 51 of the supply line, which opens in the direction of the supply flow indicated by the arrow 79.

Each control line section 59-66 is provided with a control valve 81-88 formed by a 2/2-way valve, an adjustable throttle 89 and a non-return valve 91 opening in the return flow direction 80, respectively, in the return flow direction indicated by the arrow 80.

Between the branch 75 and the supply line portions 51 to 58 and 25, respectively, the return line portions 59 to 66 are provided with a control valve 92, 93 formed by a 2/2-way valve in each branch of the supply line 76, 77, which is capable of closing and opening.

The control valve 16 is controlled by a pilot valve 30 95, which is also formed by a 2/2-way valve and is connected to a control line 96 located upstream of the supply line portion 35 from the control valve 16 and thus downstream of the check valve 97 and downstream of the control valve 16. 36 behind. In the direction of the supply flow, in front of the brick 95 of the pilot valve 6, at 98, a section 99 of the control line branches, which leads to the control connection of the pilot valve 16. In the feed direction in front of the branch point 98, two throttles 100, 101 and a throttle 102 are arranged in the control line 96 between the branch point 5 98 and the pilot valve 95. The pressure limiting valve 104 is used to ensure the pressure of the hydraulic circulation.

The control valves 81 to 84 are connected to their supply line portions 51 to 54 and return line portions 59 to 66 and 10 by a supply line branch 76 and a control valve 92 as a pre-assembled control group indicated by thin solid lines and indicated by the number 105 in Fig. 2. Similarly, there is another supply line branch 77 therein. with its control valves 85-88 and supply line 15 sections 55-58 and return line sections 63-66 combined into a pre-assembled control group 106. The pilot line 16 also forms a pilot line 95 and supply line section 39, return line branch 37 and corresponding control valves 43, 47 The connection points of the control groups 105 to 107 in these wires are indicated by the number 108. The control groups 105, 106 are arranged in the cavity of the seat 4, while the control group 107 is arranged in the lower part 3 of the chair.

Figures 3 and 4 clearly show the structure of the pilot valve 16. This is a 4/2-way valve comprising two connections 112, 113 for the supply line 31, two connections 114, 115 for the return line 32 and a connection 116 for the control line section 99.

The valve slide 117 can have two switching positions (Fig. 3, Fig. 4) and is biased to its rest position by means of a spring 33 (Fig. 3). Connected to the valve slide 117 is a monitoring pin 118 located axially on the side 35 away from the control pressure space 119 of the valve slide 117, piercing the closure portion 121 of the body tightly,

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protrudes outwards and thus enables the optical positioning and control of the respective position of the valve slider 117.

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Due to the compact construction, a large part of the control line 5 is included in the control valve 16. For this purpose, the valve slide 117 has a radial bore 122 in the region of the connection 112, which is connected to the control pressure space 119 via an axial bore 123. In the flow direction 10, chokes 100 and 101 are arranged successively in the supply flow direction 10 and are formed by screw-in nozzles. The choke 102 of Figure 2 is located in the region of the control connection 116 in the body 111.

The passages between the connections 112 to 115 are formed by notches made in the circumference of the valve slide 117. In each case, at least two notches 126, 127, 128, 129 located radially opposite one another are arranged, which act on the guide edges 130 between the supply connections 112 and 113 and on the guide edges 131 between the return connections 114, 115. In the rest position of the valve slide 117 20 according to Fig. 3, the passages between the supply connections 112 and 113 and 114 and 115 are closed, in contrast, in the operating position according to Fig. 4 they are opened. The notch 129 is dimensioned so long that in the rest position (Fig. 3) there is a passage at 132 between the supply connection 25 and the return connection 115. To restrict the flow rate, throttling grooves 133 to 137 are arranged in the region of the guide edges 130, 131 and in the region of the passage 132, each of which has radially opposite lengths L, 1 and which thus provide throttling progressivity.

The operation of the control device is explained below:

Figure 2 shows the control device in the rest position, in which the cylinder-piston units 9, 17, 21, 25, 28 are hydraulically closed. In order to start the modification operation, it is necessary to connect the motor-pump unit 14 and to change the second control valve 43, 47 of the single-acting cylinder-piston unit 9 or the other of the two control valves 92, 93 for the preselection of the movement or switching from one of the control valves 81 to 88 belonging to each double-acting cylinder-piston unit 17, 21, 25, 28 for one of the cylinder-piston units 17, 21, 25, 28. These control valves, including the pre-control valve 95, are electrically controllable .

The course of the control operation of the single-acting cylinder-piston unit 9 providing the height adjustment of the treatment chair 1 is as follows:

After switching on the motor-pump unit 15 and switching the pilot valve 94 and the control valve 43, which is preferably achieved simultaneously by means of the operating knob, the return line branch 37, 38 is first supplied at a pressure of 0.1 s. pushes to its closed position, brings the pre-controlled control valve 16 to its operating position 20 as shown in Fig. 4. The control valve 43 pushes into its open position. The cylinder-piston unit 9 now enters automatically due to the self-weight of the upper part 2 of the chair, so that the pressure fluid flows back from the pressure space through the return line branch 37 and the return line portion 36. The downstream movement is stopped by the changeover of the control valve 43, which can take place simultaneously with the disconnection of the motor-pump unit 14.

The course of the control operation of the cylinder-piston unit 21, which is actively pressurized in both pushing directions, for adjusting the inclination of the backrest 5, in particular for the purpose of lowering, is as follows:

By automatically switching the motor-pump unit 14, by switching the control valve 90 to its closed position with the following switching switches of the control valve 16 to its open position 35, by switching in the supply line branch 76

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9 82183 control valve 92 to its open position and by switching the control valve 86 in the return line section 64 to its open position, the pressure space 49 of the cylinder-piston unit 21 is supplied with pressure fluid, while the pressure space 48 is connected to the return line 32, i.e. the cylinder 21 goes in until at least the control valve 86 engages again in its closed position. Also in this case, the connection and the changeover of the respective control valves can take place simultaneously.

As can be clearly seen from Fig. 3, when the valve slide 117 is moved from its rest position, the supply line portion 39 is throttled with pressure fluid. This is done from zero to full volume flow in a time of about 0.3 s. The feed is progressive because the second throttle groove 134 starts to act only when the throttle groove 133 is already in operation due to its shorter length 1 compared to the larger length L of the throttle groove 133. The same applies to the connection of the return line branch 37, 38 to the return line portion 36, compare the throttle grooves 135, 136 of different lengths. thus, the aim is to avoid jerky movements that would be uncomfortable for the patient in the treatment chair.

Choked pressurization and discharge are also affected by a choke 102, the magnitude of which determines the change in movement of the valve slider 117 as the pilot valve 95 moves to its open position.

The subject matter described above is illustrated in Figures 5 and 6.

According to Figure 5, the pressure p is illustrated by time t. It can be seen that due to the throttled pressure structure, due to the throttled pressure in the return line branch 37, 38 and the supply line 31, the full pressure level pmax is only reached after 0.1 s + 0.3 s. Fig. 82183 shows the oblique part 141 of the curve shown, which illustrates the smooth movement of the cylinder-piston units. The corresponding soft movement is also the result at the end of the movement of the cylinder-piston units, because the removal of the pressure fluid 5 from the return line branch 37, 38 to the return line section 36 also takes place throttled in a time section of 0.3 s.

Fig. 6 similarly shows the speed v of the piston rod of the cylinder-piston units compared to time t. The result is a uniform curve due to the linear dependence.

In fact, due to the throttling pressure of the pilot valve 16 (throttles 100, 101) after the motor-pump unit 16 is connected, the working pressure is first generated in the return line branch 37, 38 via the throttle 34 15 (Fig. 2) and the throttle groove 137 (Figs. ) is of particular importance. Thus, it is achieved that in connection with both the insertion and elongation of the cylinder-piston units 17, 21, 25, 28 and in connection with the extension of the cylinder-piston unit 9, the product 20 not only has a time delay of 0.1 s but operates in the return line branch 37, 38. which, in addition to the constricted pressurization, contributes to the realization of the desired jerky movements of the cylinder-piston units.

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Claims (20)

1. Hydraulic control device for a treatment chair with several relatively adjustable chair parts, comprising a line circuit, as measured by a pump (14), cylinder-piston units (9, 17, 21, 25, 28) inserted between the chair parts, conduit connections for the cylinder-piston units are arranged in parallel, in which also in the supply lines (31), also in the return lines (32), control valves (92, 93, 81 - 88) are arranged for controlling the cylinder-piston. the units and in the supply lines (31) each a check valve (78), wherein the cylinder-piston units for avoiding jerk movements can be supplied stripped, characterized in that at least part of the cylinder-piston units (9, 17, 21, 25, 28) have been designed to be double-acting, - to provide both pressure chambers (48, 49) for the double-actuated cylinder-piston units (17, 21, 25, 28) by supply line sections (51-58) and return line sections ( 59 - 66) are associated with the supplement - in each return line section (59 - 66) of the double-acting cylinder-piston units (17, 21, 25, 28), a control valve (81 - 88) is provided, 25. that a check valve (78) is provided in the supply pipe sections (51 - 58), - that one pressure chamber (49) for each of the double-acting cylinder-piston units (17, 21, 25, 28) is connected to a first supply pipe branch (76) and the second pressure chamber (48) with a second supply line branch (77), - that a supply valve (92, 93) is also arranged in the supply line branches (76, 77), and - that the supply line (31) is upstream about 35 supply line sections (51 - 58) and in the return line. ------ - I ,. Downstream of the return line sections (59 - 66), at least one throttle (100, 101) is provided downstream (32). Control device according to claim 1, characterized in that the throttle valves (81 - 88; 92, 5 93) in the return pipe sections (59 - 66) and the supply line branches (76, 77) are 2/2-way valves. Control device according to claim 1 or 2, characterized in that a control valve 10 (16) common to the supply line (31) and the return line (32) is provided. Control device according to claim 3, characterized in that the control valve (16) is a 4/2-way valve. Control device according to any of claims 1 to 4, characterized in that the throttles (100, 101) are integrated in the control valve (16). Control device according to claim 5, characterized in that the throttles (100, 101) are formed by throttle bars (133 - 136). Control device according to claim 6, characterized in that the throttle lock (133 - 136) is designed so that the return circuit is more severely throttled than the supply. Control device according to any one of claims 4 - 7, characterized in that the control valve (16) is biased in its supply and return line (31, 32) by means of a spring (33). Control device according to claim 8, characterized in that the control valve (16) is guided against the spring (33) by means of a control valve (95). Control device according to claim 9, characterized in that the control valve (95) is a 2/2-way valve. Control device according to Claim 9 or 10, characterized in that the control valve (95) is provided in one of the supply line sections (35) upstream of the control valve (16) with the return pipe section (36) downstream of the control valve (16) connecting a control line (96) which is upstream of the control valve (95) by means of a control line branch (99) is connected to the control valve (16), and that in the flow line (96) a restriction (102) is arranged in the flow direction after the branching. Control device according to any of claims 4 -11, characterized in that in the supply pipe (31) the control valve (16) locking upstream of the supply valve section (35) is connected to the free cylinder discharge section (35). the piston unit returning return section (37, 38). Control device according to claim 12, characterized in that a throttle (34) is arranged in the passage between the supply line section (35) and the return line section (37, 38). Control device according to any one of claims 1 - 13, characterized in that the double-acting cylinder-piston units (17, 21, 25, 28) are inserted for the displacement of the treatment chair upper (3), the adjustment of the inclination for the backrest of the treatment chair (5), movement in and out of the treatment headrest (6) and / or the adjustment of the inclination of the treatment chair headrest (6). Control device according to any one of claims 1 to 14, characterized in that a simple operating cylinder-piston unit (9) is arranged for the height adjustment of the treatment chair (1). Control device according to any one of claims 1 to 15, characterized in that the return pipe sections (37, 59 - 66) adjoining in the cylindrical piston units (9, 17, 21, 25, 28) are preferably adjustable. disposable throttles (47, 89) are provided. Control device according to any of claims 1 to 16, characterized in that the valve slide (117) is 82183 for the control valve (16) is connected to an axial control pin (118) extending through the housing (111) for the control valve (16). ). Control device according to claim 7 or 8, characterized in that each at least two guide rails (133, 134; 135, 136) of different length (L, 1) are provided. Control device according to claim 6, characterized in that the throttle (100, 101) is arranged in a shunt (122, 123) mounted in the valve slide (117). Control device according to any of claims 1-19, characterized in that at least part of the control valves (81 - 88, 92, 93) arranged in the supply line branches (76, 77) and in the return line sections (59 - 66) are provided. summarized to a pre-mountable control group (105, 106), which is arranged in the heel of the treatment chair seat (4).