WO2004062545A1

WO2004062545A1 - Multi-functional bed for patient

Info

Publication number: WO2004062545A1
Application number: PCT/KR2003/000948
Authority: WO
Inventors: Choon Sik Kim
Original assignee: Angel Bed Co., Ltd.
Priority date: 2003-01-10
Filing date: 2003-05-14
Publication date: 2004-07-29
Also published as: AU2003235213A1

Abstract

The present invention discloses a patient bed. A toilet seat and a shower bath are installed on a bed body heated by a hot water, the feeding and drainage of water are automatically achieved, the toilet seat is automatically closed and shut, and an automatic portable desk provided with a basin is installed. Therefore, a patient can conduct urination and defecation by itself with no odor and sanitarily without any particular assistant or help from another person. Also, it is possible to have a shower on the bed and the temperature of the bed can be adjusted by the patient so that the patient and its nursing person can used the bed more comfortably and conveniently.

Description

MULTI-FUNCTIONAL BED FOR PATIENT

TECHNICAL FIELD

The present invention relates to a patient bed, and more particularly, to a multi-functional patient bed capable of a bowel movement, urination and shower etc. of a patient whose behavior is not free with a comfortable posture on the bed, sanitarily treating an evacuated matter of the bowel movement and urination with no stink, adjusting a temperature of the bed to a temperature which a patient requires by using hot water, and more pleasantly and conveniently using the bed by installing an automatic opening and closing stool.

BACKGROUND ART Since a conventional bed, which has been used in a hospital etc. , is not provided with means for treating feces or urine of a patient, the pctient should have treated the feces and urine by going to a washroom on a wheel chair with a help of an assistant or a nurse, or by using an auxiliary pot received in a lower part of the bed.

However, going to the washroom could bring about a suffering of the patient oneself and the assistant, a plenty of stink is generated when the auxiliary pot is used, and such a treatment of the auxiliary pot should have affected a bad sanitary influence to a person in charge .

In addition, since a conventional bed is not provided with means for solving a sho ver of the patient, the patient should have an inconvenience that the patient has to go to the washroom.

DISCLOSURE OF INVENTION

To solve the problem, it is an object of the present invention is to provide a multi-functional patient bed capable of sanitarily treating a bowel movement and urination with no stink regardless of an assist and a help of an assistant or an nurse by installing a stool and a shower bath on a bed body of the bed heated by hot water, automatically processing a water supply and a draining, and automatically opening and closing the stool; and coincidently, more conveniently using the bed since a shower on the bed is possible and a temperature of the bed is adjustable as the patient requires.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of preferred embodiments of the present invention will be more fully described in the following detailed description, taken accompanying drawings. In the drawings:

Fig. 1 is a perspective view of a patient bed of the present invention; Fig. 2 is a structural view of pipe arrangements of the patient bed of the present invention;

Fig. 3 is an enlarged cross-sectional view for illustrating a stool portion of the present invention;

Fig. 4 is a view for describing an operation state of an armrest in accordance with an embodiment of the present invention;

Fig. 5 is an enlarged cross-sectional view for illustrating an installation state of the stool in accordance with the embodiment of the present invention; Fig. 6 is a cross-sectional side view for illustrating an installation state of a slide-type stool of the bed of the present invention;

Fig. 7 is a cross-sectional view for illustrating an installation state of the slide-type stool operated by a cylinder in the bed of the present invention; Fig. 7a is a cross-sectional view for illu strating a state that a cover of the stool is engaged ; Fig. 7b is a state that the cover of the stool is lifted down; and Fig. 7c is a state that the stool being moved;

Fig. 8 is a view of an embodiment of a state that the slide-type stool, operated by a chain and a motor, is installed on the bed of the present invention; Fig. 8a is a cross-sectional view of a state that the cover of the stool is engaged; Fig. 8b is a state that the cover of the stool is lifted down ; and Fig. 8c is a state that the stool being moved;

Fig. 9 is a view of an embodiment of a state that the ςlide-type stool, operated by a gear and a motor, is installed on the bed of the present invention; Fig. 9a is a cross-sectional view of a state that the cover of the stool is engaged; Fig. 9b is a state that the cover of the stool is lifted down; and Fig. 9c is a state that the stool being moved.

* Description of major reference numerals * 1 : bed body 2 : back of a chair

3 : back switch for a bidet and a stink eliminating 4 : thermometer 5 : temperature adjuster 6 : safety valve 7 : shower bath 8 : pressure gauge 9 : secondary electric heater 10 : sewage disposal pipe 1 1 : primary electric heater 12 : stool 13: main valve 14: reducing pressure valve

15: automatic switch 16: overflow prevention threshold 17: water injection nozzle 18: stink suction nozzle

19: bidet 22: leg

23, 24: cavity 25: cleansing water supply pipe

26: solenoid valve 27: bidet hot water supply pipe

28: stink drainage pipe 29: condensation water jrain trap

30: water drainage pipe 34: armrest

35: wire 36: support roller 37: pump 38: connecting shaft

39: sewage reservoir tank 40: rotary shaft

41: fixture 42: movable frame

43: roller 44: cylinder

45: limit switch 46: cylinder 47: opening 48: inner case

49, 49':motor 50: chain

51 : support frame 59, 59': threaded shaft 60 , 60 ': nut portion 6 1 , 6 1 ': gear

62 , 62 ': water level detector 63 : check valve

64: crusher 65 : hydraulic tank

66 : water withdrawal pipe 67: safety valve

BEST MODES FOR CARRYING OUT THE INVENTION

Hereinafter, a preferred embodiment of the present invention will be fully described in conjunction with the accompanying drawings. Fig. 1 is a perspective view of a patient bed of the present invention; Fig. 2 is a structural view of pipe arrangements of the patient bed of the present invention; and Fig. 3 is an enlarged cross-sectional view for illustrating a stool portion of the present invention. In a patient bed having a bed body 1 of a bed provided with a back 2 , whose slope is adjusted, and legs 22 , and a flush stool 12 ; the bed body 1 is formed with a box shape to form a cavity for filling water and an overflow prevention projection 16 protruded on a periphery portion of an upper surface; a flush stool 12 provided with a bidet 19 is buried and installed at a center portion of an upper side of the bed body 1 ; a cavities 24 and 23 , at which a plurality of water injection nozzles 17 and stink suction nozzles 18 are installed, are formed at an inner peripheral surface of an upper side of the stool 12 ; a primary and a secondary electric heaters 1 1 and 9 are installed at an inner portion of one side of the bed body 1 ; and a water supply pipe 30 provided with a main valve 13 , a reducing pressure valve 14, and an automatic switch 15 operated when a shower bath is used, a pressure gauge 8 , a shower bath 7 , a safety valve 6 , a temperature adjuster 5 , a thermometer 4, and a back switch 3 for a bidet and a stink eliminating are installed at an outer side surface; the stool 12 is connected to an exterior sewage pipe via a sewage drainage pipe 10 ; a hydraulic tank 65 , at which a safety valve 67, a water withdrawal pipe 66 and a solenoid valve 26 on a plate are installed, is installed at a cavity 24, at which a water injection nozzle 17 in the stool 12 is installed, to be connected to an exterior water feeding pipe via a cleansing water supply pipe 25 ; the bidet 19 is connected to the bed body 1 via a bidet hot water supply pipe 27; a cavity 23 , at which a stink suction nozzle 18 is installed, is connected to an exterior air extracting motor via a stink drainage pipe 28 ; a water supply pipe 30 connected to the bed body 1 is connected to an exterior water feeding pipe; and a condensation water drain trap 29 is installed on a stink drainage pipe 28 of an exterior part of the bed body 1 to be connected to an exterior water drainage pipe.

Fig. 4 is a view for describing an operation state of an armrest in accordance with an embodiment of the present invention, armrests 34 are rotatably installed at front surfaces of both sides of a back 2 by a connecting shaft 38, each upper surface of the armrests 34 is connected to a fixture 41 on the bed body 1 by a wire 35 , and each support rollers 36 is installed on lower backs 2 of the both armrests 34 to wind the wire 35.

In addition, Fig. 5 illustrates a structure that the stool of the bed of the present invention is installed as another embodiment; a sewage reservoir tank 39 is installed on the sewage drainage pipe 10 connected to the stool 12 ; a pump 37, water level detectors 62 and 62 ', and a crusher 64 are installed therein; each individual sewage drainage pipe 10 is connected to the sewage reservoir tank 39 and the pump 37 to be connected to one sewage drainage pipe 10, and a check valve 63 is installed on the sewage drainage pipe 10 connected to the sewage reservoir tank 39.

Fig. 6 , 7a, 7b and 7c illustrate a structure of a slide-type stool of the present invention ; an inner box 48 is engaged with the stool installation portion in the bed body 1 in lateral longitudinal directions, a movable frame 42 provided with a roller 43 and reciprocated by a cylinder 46 is installed at a bottom surface therein, a cover 20 detachably inserted into an opening 47, at which the stool 12 of the bed body 1 is installed, is installed at one side of an upper surface of the movable frame 42 to be lifted up and down by a cylinder 44, the stool 12 is fixedly installed at the other side, and a limit switch 45 is installed at a position contacted when the cover 20 is lowered . At this time, the sewage drainage pipe 10 , the cleansing water supply pipe 25 , the bidet hot water supply pipe 27 and the stink drainage pipe 28 , which are connected to the stool, are made of a flexible material such as a synthetic resin or a rubber etc. to be moved freely. Fig. 8a to 8c illustrate another embodiment of the slide-type stool; the inner box 48 is engaged with the stool installation part in the bed body 1 in lateral longitudinal directions, and the movable frame 42 , at which the cover 20 and the stool 12 operated by the cylinder 44 are installed therein, is installed on a chain 50 rotated by the motor 49; and the support frame 5 1 is installed at a bottom surface of the cover 20 , and each limit switch 45 is installed at a portion contacted with the movable frame 42 when the support frame 5 1 is lowered, and portions of the bed body 1 correspond to a front side and a rear side of the movable frame 42.

Fig. 9a to 9c illustrate an embodiment of the slide-type stool operated by a gear and a motor; the inner box 48 is engaged with the stool installation part in the bed body 1 in lateral longitudinal directions, and the movable frame 42 provided with a roller 43 is installed at a bottom surface therein to be reciprocated; a nut portion 60 , with which a threaded shaft 59 is engaged, is fixedly installed at a rear side of the movable frame 42 , and the threaded shaft 59 is rotatably connected to the motor 49 and the gear 6 1 installed at the inner box 48 at the rear side of the movable frame 42 ; and one side of the upper surface of the movable frame 42 is provided with the cover 20 detachably inserted into the opening 47 , at which the stool 12 of the bed body 1 is installed, and at which the nut portion 60 ' engaged with the threaded shaft 59' is installed at a bottom surface of the movable frame 42 , the threaded shaft 59 ' is rotatably connected to the motor 49 ' and the gear 6 1 ' installed at the movable frame 42 , the stool 12 is fixedly installed at the other side, and the limit switch 45 is installed at the position contacted when the cover 20 is lowered . Hereinafter, an op eration of the present invention will b e described .

First, an operation of the stool 12 installed at the patien t bed of the present invention will be described . When the patient uses the stool 12 , the patient eases nature after he eliminates the cover 20 of the stool 12 with lain on the bed. If the switch for a bidet and a stink eliminating switch 3 installed at one side of the bed body 1 is operated, as shown in Fig. 3 , the cleansing water supplied from the exterior water feeding pipe is entered into the hydraulic tank 65 via the cleansing water supply pipe 25 to raise an air pressure in the hydraulic tank 65. When the pressure in the hydraulic tank 65 is raised up more than a predetermined pressure, the solenoid valve 26 automatically opened to supply water to the cavity 24 , at which a plurality of water injection nozzles 17 is installed, by an internal air pressure . The water is inj ected from the water inj ection nozzle 17 to cleanse the sewage in the stool, and then, drained to the external sewage pipe via the sewage drainage pipe 10. At this time, the safety valve 67 is installed at the hydraulic tank 65 connected to the cleansing water su pply pip e

25 to p revent the hydraulic tank from exploding due to an xcessive pressure by automatically opening the safety valve when the pressure in the hydraulic tank 65 is excessively raised, and the water withdrawal pipe 66 can be used when the water in the hydraulic tank 65 is forcedly drained.

In addition, the solenoid valve 26 automatically blocks up a passageway after a predetermined quantity of cleansing water is supplied.

Further, the bidet 19 is connected to the bed body 1 via the bidet hot water supply pipe 27 to supply the hot water in the bed body 1 into the bidet 19 when the bidet 19 is used. On the other hand, since the cavity 23 , at which the plurality of stink suction nozzles 18 is installed, is connected to the air extraction motor and the stink drainage pipe 28 installed at the exterior part of the bed, an operation of the air extraction motor eliminates the stink by sucking the stink in the stool through the stink suction nozzle 18 to drainage the stink to an exterior when the patient uses the stool.

At this time, the stink suction nozzle 18 sucks vapor together with the stink generated from the stool to gather the vapor with a liquid state on the stink drainage pipe 28 , and the condensation water drain trap 29 is installed at a position, where the liquid is gathered together, to drainage the stored condensed water to the water drainage pipe. The secondary electric heater 9 of the primary and secondary electric heaters 1 1 and 9 installed in the bed body 1 is connected to the exterior water feeding pipe and the water supply pipe 30 to make warm the bed like an Ondol (Korean floor heating system) by heating the water supplied to the inner part of the bed body 1 ; at this time, the user adjusts the temperature of the bed to the temperature that he wants by using the temperature adjuster 5 installed at the one side of the bed body 1 , and confirms the current temperature of the bed by seeing the thermometer 4.

When the patient has a shower by using the shower bath 7, the primary electric heater 1 1 installed at the bed body 1 is automatically operated by the automatic switch 15 to more rapidly heat the water filled in the bed body 1 to enable the shower with a warm water of a suitable temperature. At this time, the secondary electric heater 9 is operated when the temperature of the water does not come up to a desired temperature .

On the other hand, when the patient has a shower, the water in the bed is drained into the stool 12 to be drained to the sewage drainage pipe and the water drainage pipe via the sewage and stink treatment passage of the stool. Further, the overflow prevention threshold 16 is formed at a periphery portion of the upper surface of the bed body 1 to prevent the water from flowing out to an exterior to keep the circumference of the bed clean when the patient has a shower o.ri the bed .

The water in the bed body 1 is supplied through the water supply pipe 30 connected to the exterior water-feeding pipe, and the water supply pipe 30 is provided with the main valve 13 for manually feeding and blocking the water, and the reducing pressure valve 14 for automatically opening and clo sing the water supply pipe depending upon the difference between the pressure in the bed body 1 and the pressure that the user set, thereby promptly and automatically replenishing the water drained when the shower bath 7 and the stool 12 is u sed.

The pressure in the b ed body 1 can be visually confirmed through the pressure gauge 8 installed at the one side of the bed body 1 to easily recognize the water filling state in the bed body 1 to suitably set up the pressure . The safety valve 6 is installed at the one side of the bed body 1 to prevent the bed body 1 from occurring the failure and the safety accident by au tomatically operating the safety valve

6 when the pressure in the bed body 1 is excessively raised . On the other hand, as shown in Fig. 4, the armrests 34 are installed at the front surfaces of both sides of the back 2. Since the armrests 34 fixed by the wire 35 maintains a horizontal state when the back 2 is rotated about the rotary shaft 40 to and fro, the patient can keep the posture more conveniently by naturally put the arms on the armrests 34.

On the other hand, as shown in Fig. 5 , the sewage reservoir tank 39 is installed at the sewage drainage pipe 10, to which the sewage in the stool is drained; and the pump 37 connected to the individual sewage drainage pipe 10 , the water level detectors 62 and 62 ', and the crusher 64 are installed therein; therefore, the sewage drained from the stool 12 is temporarily stored in the sewage reservoir tank 39 to be drained to an exterior septic tank through the sewage drainage pipe 10, at which the check valve 63 is installed.

At this time, when the solid state sewage such as feces etc. is not smoothly drained to be accumulated in the tank 39 , the water level detector 62 ' detects the level to operate the crusher 64 to crush the sewage to easily drainage the sewage , and when the sewage is accumulated due to a difficulty of natural drainage through the sewage drainage pipe 10, the water level detecting sensor 62 detects the level again to operated the pump 37 and coincidently block the check valve 63 to forcedly drainage the sewage .

The forceful drainage operation of the sewage by the pump 37 is capable of solving the problem that the sewage is not easily drained through a relatively small diameter of the sewage drainage pipe 1 C .

When the slide-type stool installed at the bed of the present invention is used, as shown in Fig. 7a, since the opening 47 formed at the bed body 1 has been blocked by the cover 20 installed at the cylinder 44 , the bed is usually used as a general bed of a flatted upper surface; when the patient intends to have a call of nature, the switch (nor shown) for operating the cylinder, with which the cover is engaged, becomes on to operate the cylinder 44 to lower the cover 20 to open the opening, as shown in Fig. 7b.

The lowering movement of the cover 20 is stopped as the cover is lowered to contact with the limit switch 45 installed at the one side, and coincidently, as shown in Fig. 7c, another cylinder 46, installed at the rear side of the movable frame 42 , is operated to move the movable frame 42 to locate the stool 12 on the movable frame 42 at the opening 47.

As described hereinabove, after the stool is located at the opening 47 and the patient eased the nature, the switch (not shown) is re-operated to return the movable frame 42 to lift up the cover 20 to close the opening 47.

In addition, referring to the operation of the stool of the bed, at which the slide-type stool is installed, as shown in the structure of Figs. 8a to 8c, the main switch (not shown) installed at the exterior part of the bed body 1 is manipulated to operate the cylinder 44 to lower the cover 20 engaged with the opening 47 of the bed body 1 as shown in Fig. 8a to as jyhown in Fig. 8b. The cover 20 is lowered and coincidently the support frame 5 1 installed at the bottom surface is also lowered to contact the support frame 5 1 with the limit switch 45 on the movable frame 42 to operate the motor 49 , on which the chain 50 is wound. Simultaneously with the operation of the motor 49, the chain 50 is rotated and the movable frame 42 installed at the chain 50 is also moved to transfer the stool 12 toward the opening 47 of the bed body 1 as shown in Fig. 8c.

The stool 12 is conformed to the opening 47 to contact the movable frame 42 with the limit switch 45 installed at the front side and coincidently stop the rotation of the motor 49. After the patient eased the nature on the stool, when the main switch is manipulated again, the motor 49 is reversely rotated to return the mcvable frame 42 to its original position, the movable frame 42 is contacted with the limit switch 45 installed at the rear side, and the cylinder 44 is simultaneously rotated to lift up the cover. 0 to be inserted into the opening 47 of the bed body 1 and stopped.

In addition, referring to the operation of the stool of the bed, at which the slide-type stool is installed, as shown in the structure of Figs. 9a to 9c, the main switch (not shown) installed at the exterior part of the bed body 1 is manipulated to operate the motor 49 ' installed on the movable frame 42 to rotate the threaded shaft 59 ' connected to the motor 49 ' and the gear 6 1 ', to thereby lower the nut portion 60' threadedly inserted therein to lower the cover 20 engaged with the opening 47 of the bed body 1 as shown in Fig. 9b . As the cover 20 is lowered to contact with the limit switch

45 , the motor 49 connected to the movable frame 42 and the threaded shaft 59 is operated.

Simultaneously with the operation of the motor 49, the threaded shaft 59 of the gear 6 1 is rotated together, and the nut portion 60 fixed to the movable frame 42 is moved along the thread of the threaded shaft 59 to move the movable frame 42.

After the patient eased the nature on the stool moved and stopped as described hereinabove, when the patient manipulate the return switch of the main switch again, the motor 49 is reversely rotated to return the movable frame 42 to its original position, and the motor 49' on the movable frame 42 i, also reversely rotated to lift up the cover 20 to insert the cover 20 into the opening 47 of the bed body 1 and stop therein . As described hereinabove, the present invention is capable of conveniently using the flush stool, without a troublesome manual opening and closing operation of the cover, by installing the slide-type stool on the bed body of the bed, and simply manipulating the switch when the patient whose behavior is not free eases the nature.

INDUSTRIAL APPLICABILITY

As described hereinabove, the present invention is capable of a bowel movement, urination and shower etc. of a patient whose behavior is not free with a comfortable posture on the bed without a help of an assistant, sanitarily treating an evacuated matter of the bowel movement and urination with no stink, adjusting a temperature of the bed to a temperature which a patient requires by using hot water, and more pleasantly and conveniently using the bed, by installing the stool and the shower bath on the bed body, automatically feeding and draining the water, and installing an automatic opening and closing stool.

Claims

1. A multi-functional patient bed having a bed body 1 of a bed provided with a back 2 , whose slope is adjusted, legs 22 , and a mattress 3 1 ; and a flush stool 12 , characterized in that the bed body 1 is formed with a box shape to form a cavity for filling water and an overflow prevention proj ection 16 protruded on a periphery portion of an upper surface; a flush stool 12 provided with a bidet 19 is buried and installed at a center portion of an upper side of the bed body 1 ; a cavities 24 and 23 , at which a plurality of water injection nozzles 17 and stink suction nozzles 18 are installed, are formed at an inner peripheral surface of an upper side of the stool 12 ; a primary and a secondary electric heaters 1 1 and 9 are installed at an inner portion of one side of the bed body 1 ; and a water supply pipe 30 provided with a main valve 13 , a reducing pressure valve 14, and an automatic switch 15 operated when a shower bath is used, a pressure gauge 8 , a shower bath 7, a safety valve 6 , a temperature adjuster 5, a thermometer 4 , and a back switch 3 for a bidet and a stink eliminating are installed at an outer side surface; the stool 12 is connected to an exterior sewage pipe via a sewage drainage pipe 10 ; a hydraulic tank 65 , at which a safety valve 67 , a water withdrawal pipe 66 and a solenoid valve 26 on a plate are installed, is installed at a cavity 24, at which a water inj ection nozzle 17 in the stool 12 is installed , to be connected to an exterior water feeding pipe via a cleansing water supply pipe 25; the bidet 19 is connected to the bed body 1 via a bidet hot water supply pipe 27 ; a cavity 23 , at which a stink suction nozzle 18 is installed, is connected to an exterior air extracting motor via a stink drainage pipe 28 ; a water supply pipe 30 connected to the bed body 1 is connected to an exterior water feeding pipe ; and a condensation water drain trap 29 is installed on a stink drainage pipe 28 of an exterior part of the bed body 1 to be connected to an exterior water drainage pipe; armrests 34 are rotatably installed at front surfaces of both sides of a back 2 by a connecting shaft 38 ; each upper ∑rurface of the armrests 34 is connected to a fixture 4 1 on the bed body 1 by a wire 35 ; and each support rollers 36 is installed on lower backs 2 of the both armrests 34 to wind the wire 35 ; and an inner box 48 is engaged with the stool installation portion in the bed body 1 in lateral longitudinal directions; a movable frame 42 reciprocated by moving means is installed therein ; and the stool 12 , and the cover 20 , detachab ly inserted into the opening 47, at which the stool 12 of the bed body 1 is ljfted up and down to be installed, are installed at the upper surface of the movable frame 42.

2. The multi-functional patient bed according to claim 1 , characterized in that a sewage reservoir tank 39 is installed on the sewage drainage pipe 10 connected to the stool 12 ; a pump 37 , water level detectors 62 and 62 ', and a crusher 64 are installed therein; each individual sewage drainage pipe 10 is connected to the sewage reservoir tank 39 and the pump 37 to be connected to one sewage drainage pipe 10 ; a check valve 63 is installed on the sewage drainage pipe 10 connected to the sewage reservoir tank 39; and the crusher 64, the pump 37, and the check valve 63 are controlled by the water lever detectors 62 and 62 '.

3. The multi-functional patient bed according to claim 1 , characterized in that the movable frame 42 is provided with a roller 43 at a bottom surface thereof, lateral moving means of the movable frame 42 and lift up/down means of the cover 20 employs the cylinders 46 and 44, and a limit switch 45 is installed at a position contacted when the cover 20 is lowered .

4. The multi-functional patient bed according to claim 1 , characterized in that the cover 20 lifted up and down by the cylinder 44, and the movable frame 42 , at which the stool 12 is installed, are installed on the chain 50 rotated by the motor 49 to be moved; and the support frame 5 1 is installed at the bottom surface of the cover 20 , and the limit switch 45 is installed at a contact position with the movable frame 42 and the front and rear sides of the bed body 1 , respectively.

5. The multi-functional patient bed according to claim 1 , characterized in that the movable frame 42 is provided with a roller 43 at a bottom surface thereof, lateral moving means of the movable frame 42 and lift up/ down means of the cover 20 employs the motors 49 and 49'; and a nut portion 60, with which a threaded shaft 59 is engaged, is fixedly installed at a rear side of the movable frame 42 ; the threaded shaft 59 is rotatably connected to the motor 49 and the gear 6 1 installed at the inner box 48 at the rear side of the movable frame 42 ; the nut portion 60 ' is installed at the bottom surface of the cover 20 to be connected to the motor 49 ' and the gear 6 1 ' to engage with the threaded shaft 59 ' rotated together therewith ; and the limit switch 45 is installed at the position contacted when the cover 20 is lowered .