JPS6357053B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive device for raising and lowering the floor of a bed.

A bed configured to raise and lower the floor by dividing the floor on which a patient lies on its back into a plurality of parts and rotating and lowering the desired floor in an appropriate direction, or raising and lowering a floor support frame that supports the floor. In a bed configured so that the entire floor can be raised and lowered while keeping it horizontal, or a bed configured such that the entire floor is tilted by raising or lowering only one of the head side or foot side of the floor support frame, A reciprocating device is installed in a lifting mechanism configured below the floor, and the floor is raised and lowered by the reciprocating device. Such reciprocating devices include devices in which a female thread is screwed onto a screw shaft and the female screw is reciprocated by forward and reverse rotation of the screw shaft, as well as pneumatic or hydraulic cylinder devices. However, a device in which a female thread is screwed onto the screw shaft occupies a large space, is heavy, and requires an electric motor for each screw shaft, which increases the price. The disadvantage is that it imposes a large burden. In addition, pneumatic or hydraulic cylinder devices require an air compressor or hydraulic pump as a pressure source.
Various valve elements such as pressure reducing valves, pressure regulating valves, control valves, etc. are required, and their piping is relatively complex, so a large amount of space is required to combine them into a single device. This method has the disadvantage of being expensive and requiring a very large-scale device. In addition to these disadvantages in terms of space and cost, these methods cannot be applied to beds because the operating noise of the air compressor or hydraulic pump as a pressure source is extremely loud, and other problems such as maintenance and management are required. There's a big problem.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the conventional lifting drive device, and the present invention is an extremely novel system that uses a single-acting cylinder operating rod that is completely different from the conventional pneumatic or hydraulic type. The present invention provides a drive device for lifting and lowering the floor of a bed which is compact and inexpensive and operates extremely quietly by reciprocating the device using a rational method.

The present invention will be described in detail below based on examples.

Reference numeral 1 indicates a single-acting cylinder, 2 a piston, and 3 an actuating rod. Although the single-acting cylinder 1 shown in the drawings is a piston type, it may also be a plunger type. The pressurizing chamber 4 of the single-acting cylinder 1 is filled with working fluid F in a sealed manner with respect to the outside air. As the working fluid F, a fluid that easily undergoes a phase change between a gas phase and a liquid phase at around room temperature is used, such as water vapor or fluorocarbon gas.
For example, Freon 113 (boiling point
47.6℃), Freon 11 (boiling point 23.8℃), Freon 21 (boiling point
8.9℃), Freon 114 (boiling point 3.8℃), etc. can be used. These fluids, namely water vapor (boiling point
The choice of whether to use a fluorocarbon gas (100℃) or a fluorocarbon-based gas as the working fluid of the present invention depends on the fluid's stability, corrosivity, toxicity, heat capacity that leads to thermal response, and considerations for heating, cooling, and heat retention. It can be determined by taking into consideration various conditions such as operating temperature related to the configuration. For example, for fluorocarbon gases, Freon 114 is suitable from the standpoint of toxicity and stability, and Freon 21 and Freon 114 are suitable from the standpoint of heat capacity.
Judging comprehensively from these points, fluorocarbons
It can be said that 114 is suitable.

Therefore, the single-acting cylinder 1 is provided with a heat pipe 5 whose one side is located inside the pressurizing chamber 4 and the other side is located outside the pressurizing chamber 4, and the heat pipe 5 corresponds to the other side of the heat pipe 5. Then, a heating means 6 and a cooling means 7 are attached to the outside of the single acting cylinder 1. Reference numerals 8 and 9 are fins.

Figures 2 and 3 show a bed that raises and lowers the floor;
In addition, FIG. 2 shows a specific example of a mechanism for raising and lowering a floor part in such a case, and FIG.
The end of a desired floor portion 10' to be raised and lowered is rotatably fixed to a floor support frame 11, an operating rod 12 is provided on the underside of the floor portion 10', and an operating member 13 is attached to the operating rod 12. is provided in a protruding manner, and the actuating member 13 is displaced to push up the actuating rod 12 and rotate the floor portion 10', thereby undulating the floor portion 10 into a desired shape. In the figure, rotating rods 14, 14' are provided on the lower side of the floor support frame 11, and rotating arms 15, 15' are provided protruding from both ends of the rotating rods 14, 14'. The movable arms 15, 15' are connected to support arms 17, 17' provided on the base 16, and the operating members 18,
By displacing the operating members 18, 18' and rotating the rotating arms 15, 15', the rotating rods 14, 14' are raised, thereby raising the floor support frame 11. The floor support frame 11 can be raised in a parallel state, or the floor support frame 11 can be tilted by displacing only one of the operating members 18, 18'. Incidentally, the raising and lowering form of the floor portion 10 of the bed and the structure of its raising and lowering mechanism may be of any construction other than the above-mentioned construction.

Thus, the single-acting cylinder 1 is connected to the floor portion 10.
The floor section 10 is raised and lowered by the reciprocating movement of the actuating rod 3 of the single-acting cylinder 1. Specifically, in the configuration shown in FIG. 2, the actuation rod 3 is connected to the actuation member 13, and the main body of the cylinder 1 is fixed to the floor support frame 11 and installed in the lifting mechanism, and the configuration shown in FIG. Also in this case, the actuation rods 3, 3' are connected to the actuation members 18, 1.
8', and the main bodies of the cylinders 1, 1' are fixed to the floor support frame 11. By installing the single-acting cylinder 1 in the elevating mechanism of the floor 10 in this manner, the forward movement of the actuating rod 3, that is, the movement in the direction in which the actuating rod 3 extends from the cylinder 1 in the figure, is achieved. The floor part 10' or the floor support frame 11 can thus be raised against gravity, and by a reciprocal movement, ie a movement in the direction in which the actuating rod 3 is retracted into the cylinder 1 in the figure. Conversely, it can be lowered.

In the present invention, the single-acting cylinder 1 is installed in the elevating mechanism of the floor 10 as described above, and a heating means is provided for heating and cooling the working fluid F in order to reciprocate the working rod 3. 6 and the cooling means 7 are attached to the outside of the single-acting cylinder 1 through the heat pipe 5, so even if the position where the single-acting cylinder 1 is installed is restricted by the lifting mechanism, the heating means 6 Furthermore, there are no restrictions on the location where the cooling means 7 is installed.

The operation of the present invention in such a configuration will be described below with reference to the thermal cycle diagrams in ideal operation shown in FIGS. 4a and 4b. Note that FIG. 4a shows the relationship between the pressure inside the pressurizing chamber 4 and the enthalpy of the working fluid F, and FIG. 4b shows the relationship between the internal pressure of the pressurizing chamber 4 and the volume of the pressurizing chamber 4.

First, when the pressurizing means 6 is activated to heat the working fluid F, the enthalpy of the working fluid F gradually increases. As a result, the pressure in the pressurizing chamber 4 gradually increases, and the actuating rod 3 can be moved against the load of the bed floor 10 applied to the actuating rod 3 via the actuating members 13, 18, 18'. After reaching the pressure P ₁ , the working fluid F pushes the piston 2 and expands, so that the forward movement of the working rod 3 displaces the working members 13, 18, 18', causing the floor member 10' or The floor support frame 11 can be raised against gravity. Next, when the cooling means 7 is operated to cool the working fluid F, the enthalpy of the working fluid F gradually decreases, and the pressure inside the pressurizing chamber 4 decreases due to the frictional force between the cylinder 1 and the piston 2, etc. After reaching a pressure _P2 lower than the pressure _P1 , the working fluid F passes through the working rod 3 to the floor 10.
Due to the load, the piston 2 is compressed and the volume is contracted, so that the actuating rod 3 is moved back and the floor portion 10' or the floor support frame 11 can be lowered. Incidentally, FIGS. 5a and 5b show the measurement results of the operation of the single-acting cylinder 1 in the present invention. In this case, heating was performed by an electric heater, and cooling was performed by natural cooling by the fins 9 and by forced cooling of the fins 9 by a small ventilation fan. Further, in the embodiment, the movement in the direction in which the actuating rod 3 extends from the cylinder 1 is defined as a forward movement, and the movement in the direction in which it contracts into the cylinder 1 is defined as a backward movement, but it goes without saying that the reverse movement may be used.

As mentioned above, the working fluid F, which performs the above operations by heating and cooling, undergoes a phase change between a gas phase and a liquid phase at around room temperature, such as water vapor, fluorocarbon gas, etc. Since a liquid that is easily evaporated is used, the rate of expansion and contraction of volume during evaporation and condensation between the liquid phase and the gas phase is extremely large, and the operation of the present invention is performed at the boundary between the liquid phase and the gas phase. As a result, the aforementioned working rod 3 can be reciprocated at around room temperature without changing the temperature of the working fluid F, and heating and cooling can be performed using a heating means with a simple structure. 6
Furthermore, since the heat is transferred from the heating means 6 and the cooling means 7 to the working fluid F via the heat pipe 5, a fast response speed can be obtained.

Since the present invention is as described above, it has the following effects compared to conventional devices that raise and lower the floor by hydraulically or pneumatically reciprocating the actuating rod 3. That is, the present invention does not require any air compressor or hydraulic pump as a pressure source, and also does not require valve elements such as pressure reducing valves, pressure regulating valves, control valves, etc., and essentially heats the working fluid. Since it can be constructed from only the cooling means and control elements such as switches for controlling them, it can be constructed very compactly as a single device.
Since no expensive parts are required, the total cost can be extremely reduced.There are few components, and the structure is simple.There are no or very few moving parts, so there are fewer breakdowns and easy maintenance. , also very easy to operate,
By adjusting the amount of heating or cooling, it is possible to control the pressure inside the pressurizing chamber using only the heating means or the cooling means, and therefore the moving speed of the working rod can be easily adjusted. 1.8 is an example of operation when using Freon 114
It is possible to perform ultra-low speed movements such as mm/min without stick slips, and it is possible to raise and lower the floor according to the patient's condition on the bed without causing discomfort to the patient. It has great effects such as making the sound extremely low. In addition, the present invention uses a heat pipe as a heat transfer means, so that heating means and cooling means for heating and cooling the working fluid when operating the single-acting cylinder are attached to the outside of the single-acting cylinder. Because of this structure, even if the position where the single-acting cylinder itself is mounted is restricted by the elevating mechanism, the position where the heating means and cooling means are installed is not restricted, and the degree of freedom is high. The present invention uses a substance that easily changes phase between a gas phase and a liquid phase at around room temperature, such as water vapor or fluorocarbon gas, as the working fluid. Compared to conventional cylinder devices that use a substance that undergoes a phase change between solid and liquid phases to expand and contract, the expansion and contraction rate is significantly greater, and the reciprocating stroke of the actuating rod is therefore longer. This allows flexibility in the configuration of the floor lifting mechanism, and also allows for good heat transfer of the working fluid within the pressurized chamber to the entire body by convection, and also allows for a heating means and a cooling means. Since heat transfer is carried out by a heat pipe, the response speed when switching the actuating rod from forward motion to backward motion and from backward motion to forward motion is fast. Furthermore, since the working fluid in the heat pipe and the working fluid in the pressurizing chamber are independent, conditions such as the pressure of the working fluid in the heat pipe are independent of conditions such as the pressure of the working fluid in the pressurizing chamber. This has the effect of providing a high degree of freedom in design.
Note that the term "bed" in the above description refers to a bed on which a patient lies on his or her back, and includes not only so-called beds, but also examination tables, treatment tables, patient transport vehicles, and the like.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing an embodiment of the present invention, Figure 2 is an explanatory diagram showing an embodiment of the present invention.
Fig. 3 is an explanatory diagram of an embodiment of the bed to which the present invention is applied, Fig. 4 a, b is an explanatory diagram of the operation of the single-acting cylinder of the present invention, and Fig. 5 a, b is a measurement of the operating state of the present invention. It is a result explanatory diagram. Code, 1...Single-acting cylinder, 2...Piston, 3...Working rod, 4...Pressure chamber, 5...Heat pipe, 6...Heating means, 7...Cooling means,
8, 9...fin, 10...floor section, 10'...floor section, 11...floor support frame, 12...operating rod, 1
3... Operating member, 14, 14'... Rotating rod, 15,
15'... Rotating arm, 16... Base, 17, 17'...
...Support arm, 18, 18'... Working member, F... Working fluid.

Claims (1)

[Claims] 1 The pressurizing chamber of a single-acting cylinder is filled with a working fluid that easily undergoes a phase change between a gas phase and a liquid phase at around room temperature, and one side is filled with the pressurizing chamber and the other side is sealed with respect to the outside air. A heat pipe whose side is located outside the pressurizing chamber is provided, a heating and cooling means is attached to the outside of the single-acting cylinder in correspondence with the other side of the heat pipe, and the single-acting cylinder is The mechanism is such that the floor is raised and lowered by the reciprocating motion of a working rod that is connected to the lifting mechanism of the floor, and the working fluid is heated by the heating means from the outside of the single-acting cylinder via the heat pipe. The actuating rod of the single-acting cylinder is moved forward by heating and expanding, and the actuating rod is moved backward by cooling and contracting the working fluid by the cooling means. A driving device for raising and lowering the floor of a bed.