Bed with a lifting frame

Abstract

To reduce physical burden on a carer in lifting up a patient.SOLUTION: A bed includes: a bottom 2t; lifting frames 9, 11, 13 for supporting the bottom 2; and lifting mechanisms 15, 16 for lifting the lifting frames. The largest bottom height H2 being the height of an upper surface of the bottom when the height of the lifting frames is the maximum is equal to or more than 69 cm, 71 cm, 72 cm, 73 cm, 74 cm, 76 cm, 77 cm, or 80 cm. A lifting span H3 of the lifting mechanisms is equal to or more than 44 cm, 46 cm, 47 cm, 48 cm, 49 cm, 51 cm, 52 cm, or 55 cm. Arrangement of the X-links 15 and the lifting actuator 16 is improved in order to realize the above dimensions.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a bed in which a frame supporting a bottom can be raised and lowered by an actuator, and particularly relates to improvements in the height of the bottom and the lifting mechanism thereof.

Background Art

[0002] This type of conventional device is described, for example, in Patent Document 1.

[0003] Patent Document 1 discloses a bed in which a frame supporting a bottom is raised and lowered by an actuator. Also, 70 centimeters is exemplified as the maximum value of the frame height supporting the bottom, and 20 centimeters is exemplified as the minimum value.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In this type of nursing or medical bed, the height of the upper surface of the bottom affects not only the patient himself / herself but also the caregiver. In particular, the height of the upper surface of the bottom (hereinafter referred to as the "maximum bottom height") when the lifting frame is at its highest (in a flat state) greatly affects the physical burden on the caregiver when caring for the patient's body. For the caregiver, if the maximum bottom height is too low, when lifting or moving the patient's body, the amount of bending or tilting the legs and waist may become excessive, resulting in a large physical burden. However, to the inventors' knowledge, information regarding an appropriate maximum bottom height from this perspective is not found in the prior art.

[0006] For example, Patent Document 1 exemplifies 70 cm as the maximum height for a lifting frame. However, Patent Document 1 does not provide any information on whether this value is appropriate from the standpoint of reducing the physical burden on caregivers. Therefore, this value is of no use whatsoever for improving actual beds from the above perspective.

[0007] Furthermore, the inventors' research revealed that a significant number of caregivers found the maximum bed height of currently available commercially too low, making their work difficult. The maximum bed height of commercially available beds was approximately 57cm to 67.5cm (depending on the model).

[0008] From the above perspective, it is preferable that the maximum bottom height be higher than that of currently available commercially available beds. However, attempting to achieve this would create new technical problems. Specifically, to increase the maximum bottom height (without increasing the minimum bottom height), it is necessary to increase the lifting span of the bed's lifting mechanism. This may involve increasing the size of bed components involved in the lifting mechanism and increasing the load on the lifting actuator. As a result, the amount of deformation of each part of the bed due to the load may increase, potentially leading to greater flexing and bouncing of the bed during use. In addition, the enlarged bed components may not fit into the cargo bed of typical transport vehicles (in Japan, relatively small vehicles such as minivans and kei wagons are widely used). These various practical constraints make it difficult to increase the maximum bottom height beyond that of currently available commercially available beds.

[0009] One objective of the present invention is to achieve a maximum bottom height in a bed with a height-adjustable bottom that reduces the physical burden on the caregiver.

[0010] Another object of the present invention is to provide a structural improvement for increasing the maximum bottom height in a bed with a height-adjustable bottom, under the various technical constraints described above. [Means for solving the problem]

[0011] According to one embodiment, the bed has a maximum bottom height of 69 cm or more, 71 cm or more, 72 cm or more, 73 cm or more, 74 cm or more, 76 cm or more, 77 cm or more, or 80 cm or more. The further the height range is from the top, the greater the physical burden on the caregiver is reduced. For example, a maximum bottom height of 72 cm or more, more specifically 72 to 77 cm, is quite preferable. Furthermore, a maximum bottom height of 77 cm or more, for example 77 to 82 cm, is even more preferable.

[0012] To achieve such a maximum bottom height, the lifting span, which is the difference between the highest and lowest heights of the lifting frame, is preferably 44 cm or more, 46 cm or more, 47 cm or more, 48 cm or more, 49 cm or more, 51 cm or more, 52 cm or more, or 55 cm or more. For example, a lifting span of 47 cm or more, more specifically, within the range of 47 to 52 cm, is quite preferable.

[0013] To achieve such a desirable lifting span and obtain a desirable maximum bottom height, various technical constraints arise, such as limitations on increasing the bed size and limitations on bed deflection and bouncing. Under these constraints, in order to achieve a desirable lifting span and a desirable maximum bottom height, one embodiment has several improvements to the structure, dimensions, and arrangement of the lifting mechanism.

[0014] The rationale for the preferred conditions for the maximum bottom height and lifting span mentioned above, as well as the improvements to the lifting mechanism required to achieve them, will become clear from the following explanation. [Brief explanation of the drawing]

[0015] [Figure 1] An overall perspective view of a bed according to one embodiment is shown. [Figure 2] The images show the bed's lifting frame in its lowest and highest positions. [Figure 3] A simple model illustrates the relationship between the sinking posture of a caregiver when they begin to lift a patient's body from the bed and the height of the bed base. [Figure 4] A simple model shows the method of an experiment for investigating the amount of subsidence when a caregiver lifts. [Figure 5] The results of the above experimental investigation are shown. [Figure 6] A simple model shows the dimensions of each part of the human body used for calculating the preferable maximum bottom height. [Figure 7] A longitudinal sectional side view showing the bottom lifting mechanism by cutting through the bed according to one embodiment is shown. [Figure 8] A perspective view looking up from below the center frame is shown so that the arrangement of the guide rail for moving the upper end of the foot side of the X-link of the bed can be understood. [Figure 9] A side view of the main part of the lifting mechanism when the lifting mechanism is at the lowest position in the bed is shown. [Figure 10] A perspective view of the mechanism for fixing the upper end of the head side of the X-link of the bed is shown. [Figure 11] A perspective view of the guide rail for moving the upper end of the foot side of the X-link of the bed is shown.

Mode for Carrying Out the Invention

[0016] FIG. 1 shows an overall perspective view of a bed according to one embodiment.

[0017] As shown in FIG. 1, the bed 1 has a bottom 2, and usually, a mattress is laid thereon, and a patient lies horizontally thereon. The bottom 2 has, for example, a back bottom 2A that supports the upper body of the patient, a waist bottom 2B that supports the buttocks (waist) of the patient, a knee bottom 2C that supports the thighs of the patient, and a foot bottom 2D that supports the lower legs and feet of the patient. The sub-bottoms 2A to 2D thereof can be driven by one or more electric actuators and move so as to bend relative to each other. The back bottom 2A may have an upper back bottom 2E that supports the portion from approximately the upper half of the thoracic vertebra column in the upper body to the head, and a lower back bottom 2F that supports the portion from approximately the lower half of the thoracic vertebra column in the upper body to the lumbar vertebra column. The upper and lower back bottoms 2E and 2F may be driven by one or more electric actuators and move so as to bend relative to each other.

[0018] In the following description, the longitudinal direction 3 of the bottom 2 is referred to as the "length direction" of the bed, and the direction 4 orthogonal thereto is referred to as the "width direction" of the bed. Also, in the length direction 3 of the bed, the side closer to the head of the patient lying on the bottom 2 (or the direction toward the head) is referred to as the "head side" (or "head direction"), and the opposite side (or the opposite direction) is referred to as the "foot side" (or "foot direction"). Further, in the width direction 4 of the bed, the right side (or the right direction) of the patient lying on the bottom 2 is referred to as the "right side" or simply "right" (or "right direction"), and the left side (or the left direction) is referred to as the "left side" or simply "left" (or "left direction").

[0019] The bottom 2 is mounted on lift frames 9, 11, 13 that can be raised and lowered vertically. The lift frames 9, 11, 13 have a center frame 9, a head frame 11, and a foot frame 13, and they are fixedly coupled to each other to form one frame. The head frame 11 is fixed to the head-side end in the length direction of the center frame 9, and the foot frame 13 is fixed to the foot-side end. A head board 5 is attached to the head-side end of the head frame 11, and a foot board 7 is attached to the foot-side end of the foot frame 13.

[0020] The lift frames 9, 11, 13 are supported and lifted by a lifting mechanism having the following configuration. This lifting mechanism has a pair of X-link mechanisms 15 on the left and right sides separated in the width direction of the bed, and an electric lifting actuator 16 that drives this pair of X-link mechanisms 15. The pair of X-link mechanisms 15 and the lifting actuator 16 are mounted on a base frame 17.

[0021] Each X-link mechanism 15 on the left and right sides has a rod-shaped first link 15A and a second link 15B, and the first link 15A and the second link 15B are axially connected to each other at their respective longitudinal midpoints so as to be rotatable. Each X-link mechanism 15 on the left and right sides (first link 15A and second link 15B) is connected to the base frame 17 at its lower end and to the center frame 9 at its upper end. The pair of left and right X-link mechanisms 15 are interconnected by multiple beams 18 and move as a single unit.

[0022] The lifting actuator 16 has an electric motor 19 and a cylinder 21 that extends and retracts when driven by the electric motor 19. The point of force at the tip of the cylinder 21 is rotatably axially connected to one of the beams connecting the pair of X-link mechanisms 15. When the cylinder 25 extends, the upper ends of the pair of X-link mechanisms 15 rise, causing the lifting frames 9, 11, 13 and the bottom 2 above them to rise. Conversely, when the cylinder 25 retracts, the lifting frames 9, 11, 13 and the bottom 2 descend.

[0023] The base frame 17 has a pair of main beams 23 on the left and right sides that extend in the longitudinal direction of the bed. These two main beams 23 are interconnected by several beams that extend in the width direction, forming a nearly rectangular, integrated base frame 17 as a whole. Feet 25 are attached to each of the four corners of the base frame 17, for example. These feet 25 lift the base frame 17 (especially the pair of main beams 23) a certain distance above the building floor. The gap between the building floor and the underside of the main beams 23 of the base frame 17 can be used to insert, for example, the legs of an auxiliary table (for eating meals in bed).

[0024] The lower end of the lifting actuator 16 (e.g., electric motor 19) is rotatably attached to one of the multiple beams connecting the pair of main girders 23 of the base frame 17, for example, one beam 27 located near the foot end of the base frame 17 (e.g., the one closest to the foot). This beam 27 that supports the lifting actuator 16 will be hereinafter referred to as the "support beam". When a patient gets on or moves on the bed 1, or when the lifting actuator 16 extends and raises the lifting frames 9, 11, and 13, a large load is applied to the support beam 27 from the actuator 22. If the support beam 27 were a simple straight rod shape like the other beams, the large load could cause the support beam 27 to deflect, potentially causing the pair of main girders 23 to deflect inward by a non-negligible amount, narrowing the distance between them. These deflections could cause non-negligible fluctuations or bounces in the height of the bottom 2.

[0025] To mitigate this problem, the support beam 27 has a roughly V-shape that is set back in the direction of the load applied to the support beam 27 from the lifting actuator 16 (i.e., a diagonal direction combining downward and foot directions). That is, the support beam 27 has a central part 27A and two arm parts 27B that extend from both the left and right ends of the central part 27A in the left and right directions and are connected to the left and right main girders 23. The central part 27A is the lowest and set back part of the support beam 27 in the foot direction, and the lower end of the lifting actuator 16 is attached to it. The left and right arm parts 27B each extend from both ends of the central part 27A in the left and right directions, upward and in the head direction, and are connected to the left and right main girders 23. Because of this roughly V-shape, even when a large load is applied to the support beam 27 from the actuator 22, a considerable portion of that load is borne by the tensile stress of the two arms 27B. As a result, the deflection of the support beam 27 is smaller compared to when the beam 27 had a straight shape, thus mitigating the aforementioned problems of deflection or bouncing of the bed 1.

[0026] To further mitigate this problem (particularly the inward deflection caused by the narrowing of the distance between the pair of main girders 23), reinforcing beams 29 are positioned near the support beams 27 and at a head-side position relative to the support beams 27. The auxiliary beams 29 connect the pair of main girders 23 to each other and counteract the force that would cause the main girders 23 to deflect inward.

[0027] Figure 2 shows a side view (A) of the bed 1 according to this embodiment when the lifting frames 9, 11, and 13 are at their lowest position and a side view (B) when they are at their highest position.

[0028] As shown in Figure 2(A), the lowest height H1 of the top surface of the bottom 2 (in a flat state) (hereinafter referred to as the "minimum bottom height") is easier to use if it is low, for example, preferably 31 cm or less, more preferably 30 cm or less, even more preferably 26 cm or less, and even more preferably 25 cm or less. On the other hand, as shown in Figure 2(B), the highest bottom height H2 (i.e., the highest height of the top surface of the bottom 2 (in a flat state)) is easier to use if it is moderately high, for example, preferably 69 cm or more, more preferably 71 cm or more, even more preferably 72 cm or more, even more preferably 73 cm or more, even more preferably 74 cm or more, even more preferably 76 cm or more, even more preferably 77 cm or more, and even more preferably 80 cm or more.

[0029] To achieve these preferred minimum bottom height H1 and maximum bottom height H2, the lifting span H3 of the lifting mechanism is required to be moderately large, for example, preferably 44 cm or more, more preferably 46 cm or more, even more preferably 47 cm or more, even more preferably 48 cm or more, even more preferably 49 cm or more, even more preferably 51 cm or more, even more preferably 52 cm or more, and even more preferably 55 cm or more.

[0030] The following explanation, with reference to Figures 3 to 6, will describe the rationale for the preferred range of the maximum bottom height H1 (69 cm or more, 71 cm or more, 72 cm or more, 73 cm or more, 74 cm or more, 76 cm or more, 77 cm or more, or 80 cm or more) being preferable from the standpoint of reducing the physical burden on caregivers.

[0031] Figure 3 shows a simple model illustrating the relationship between the sinking posture of a caregiver when they begin to lift a patient's body from the bed and the height of the bed base.

[0032] As shown in Figure 3, a mattress 31 is usually placed on the bed 1, and the patient 33 lies on it. When the caregiver 35 lifts or tilts the patient 33, as shown by the solid line in the figure, the caregiver 35 slightly leans their upper body forward, lets their arms hang down and makes contact with the underside of the patient's body (making contact with the top surface of the mattress), and then bends their knees and sinks their hips down, using the strength of both their upper and lower body to lift the patient 33. Hereafter, this posture will be referred to as the "lifting initiation posture".

[0033] According to the inventors' research, if the angle of inclination of the caregiver 35's upper body relative to the vertical is approximately 20 degrees or less at the start of this lifting position, the strain on the caregiver 35's waist during lifting is small enough that it does not become a problem. The amount of sinking of the waist due to the caregiver 35 bending their knees (the difference in waist height compared to a posture with straight knees, shown by the dotted line) D (hereinafter referred to as "sinking amount") affects the amount of physical strain on the caregiver 35. In other words, if the sinking amount D is within a certain appropriate range, the caregiver 35 can easily lift the patient 33. However, if the sinking amount D is greater than that appropriate range, the caregiver 35 will feel strained because the bed is too low and they have to bend their legs and waist significantly. Conversely, if the sinking amount D is less than that appropriate range, the caregiver 35 will feel strained because the bed is too high and they have to lift the patient 33 using only their arms and shoulders.

[0034] If the bottom surface height H of bed 1 can be raised to a height that minimizes the amount of sinking D within the above-mentioned appropriate range, then by adjusting the bottom surface height H with the lifting mechanism, the amount of sinking D can always be kept within the above-mentioned appropriate range. In other words, if the maximum bottom surface height H2 of bed 1 (i.e., the maximum value of the bottom surface height H) is greater than or equal to the height that minimizes the amount of sinking D within the above-mentioned appropriate range, then the amount of sinking D can always be kept within the above-mentioned appropriate range. Therefore, once the minimum value of the above-mentioned appropriate range for the amount of sinking D is determined, a desirable value for the maximum bottom surface height H2 can be determined.

[0035] In other words, if we define D1 as the minimum value within the appropriate range of sinking amount D, then if we can determine the hand height X when caregiver 35 assumes the posture shown by the dotted line in Figure 3 (upper body tilted 20 degrees, knees straight, arms hanging down) and the thickness T of mattress 31 (the thickness of the mattress when the patient lies on it and it sinks slightly), then the preferred value of the maximum bottom height H2 can be determined using the formula "X-D1-T". Regarding the thickness T of mattress 31, based on research of various existing mattresses, it was found that the average thickness of the part that sinks when a person lies supine is 6 cm.

[0036] Figure 4 shows a simplified model of the experimental method conducted by the inventors to identify the minimum value within the appropriate range of sinking amount D when caregiver 35 is in a lifting position.

[0037] As shown in Figure 4(A), a weight 39 was placed on a height-adjustable table 37, and the height Y1 of the table 37 was measured when the subject 41, with their knees straight and upper body tilted at a 20-degree angle, held their arms down and grasped the handle of the weight 39 with their hands. Subsequently, the height of the table 37 was gradually lowered, and at each table height, the subject 41 was instructed to perform the following task. That is, after the subject 41 assumed the lifting starting position shown in Figure 4(B), the subject 41 was instructed to lift the weight 39 as shown in Figure 4(C), and it was examined whether they were able to lift it easily (i.e., whether they felt no physical strain). The highest table height Y2 at which the weight could be easily lifted was measured. The difference D1 between this highest table height Y2 at which the weight could be easily lifted and the table height Y1 when the knees were straight was calculated. This height difference D1 corresponds to the minimum value of the sinking amount D, as explained with reference to Figure 3.

[0038] This investigation was conducted by varying the weight of the weight 39 to 17 kg, 25 kg, and 35 kg. The weight range of 17 kg to 35 kg represents a common range of weights that caregivers typically lift when lifting or tilting parts of a patient's body. For each of these weights, the above experimental investigation was conducted with 41 subjects (30 men and women) ranging in height from 161 cm to 184 cm.

[0039] Figure 5 shows the results of the above survey.

[0040] As shown in Figure 5, the minimum sinking depth D1 that could be easily lifted varied among subjects at all weights. This was thought to have little correlation with the subjects' height and depended on each person's muscle strength. Therefore, the average values ​​D2, D3, and D4 of D1 were calculated for each weight. The average D2 for 17kg was 2.6cm, the average D3 for 25kg was 3.3cm, and the average D4 for 35kg was 4.6cm, indicating that it was roughly proportional to the weight. Since the lifting weight on caregivers differs for each caregiving task, the average values ​​D2, D3, and D4 for each weight were further averaged to obtain the average value D5 for the entire weight range from 17kg to 35kg, which was 3.5cm. This overall average value D5 was adopted as the minimum sinking depth D1. In other words, the minimum sinking depth D1 was identified as 3.5cm.

[0041] Figure 6 shows a simple model (an illustration excerpted from the data book below) illustrating the dimensions of various parts of the human body, which were used to calculate the hand height X when caregiver 35 tilts their upper body 20 degrees and extends their knees, as indicated by the dotted line in Figure 3.

[0042] Figure 6(A) shows the acromion height L1 in a person standing upright, Figure 6(B) shows the grip axis height L2 in a person standing upright, and Figure 6(C) shows the trochanter height L3 in a person standing upright. According to the publicly available document "Japanese Human Body Dimensions Data Book 2004-2006," published by the Human Life Engineering Research Center, the average acromion height L1 for adult Japanese men (40-49 years old, the largest age group among caregivers) in the 95th percentile is 146.1 cm, the grip axis height L2 is 82 cm, and the trochanter height L3 is 93.2 cm.

[0043] Using these dimensions L1 to L3, the calculations showed that the hand height X, as shown in Figure 3, was approximately 79.5 cm. Subtracting the minimum amount of sinking D that can be easily lifted, D1 (3.5 cm), shown in Figure 5, and the average mattress thickness T (6 cm), shown in Figure 3, from this hand height X (78.5 cm), we obtained the preferred minimum value for the maximum bottom height H2, which was approximately 69 cm.

[0044] In other words, if the maximum bottom height H2 is 69 cm or higher, it will be possible to achieve a bed height that allows nearly 95 percent of Japanese male caregivers (40-49 years old), the age group with the most caregivers, to provide care comfortably.

[0045] While caregivers in typical Japanese homes may not wear shoes, they do in nursing homes and hospitals. However, the above calculation does not take into account the heel height of the shoe. Therefore, if we take into account the heel height of the shoe (the combined thickness of the heel and insole is generally about 3 cm, and sometimes more), the desirable maximum bottom height H2 becomes 72 cm or higher.

[0046] Furthermore, the average acromion height L1 for adult Japanese men (40-49 years old) in the 99th percentile, as listed in the above data book, is 150.2 cm, grip axis height L2 is 83.8 cm, and trochanter height L3 is 95.6 cm. Using these values, the hand height X calculated above was approximately 80.5 cm. Based on this hand height X (80.5), the same calculation as above was performed.

[0047] As a result, if the maximum bottom height H2 is 71 cm or higher, nearly 99 percent of Japanese male caregivers in the most common age group can comfortably provide care without wearing shoes. If shoes are worn, the preferable maximum bottom height H2 is 74 cm or higher.

[0048] Furthermore, according to the data book mentioned above, the only age group considered to have a greater height than the 40-49 age group, which is the most common age group among caregivers used in the above calculations, is 30-39 years old. Therefore, 30-39 years old was considered to be the tallest age group among all age groups (20-79 years old) listed in the same data book. For Japanese adult males aged 30-39, the average acromion height L1 for the 99th percentile is 153 cm, the grip axis height L2 is 85.5 cm, and the trochanter height L3 is 97.1 cm. Using these values, the above hand height X was calculated to be approximately 82.2 cm. Based on this hand height X (82.2), the calculation was performed in the same manner as above.

[0049] As a result, if the maximum bottom height H2 is approximately 73 cm or higher, nearly 99 percent of Japanese male caregivers (of all age groups) can comfortably provide care without wearing shoes. If shoes are worn, the preferable maximum bottom height H2 is 76 cm or higher.

[0050] Furthermore, in the above calculation, the minimum value D1 for the amount of sinking D that can be easily lifted was set to 3.5 cm, which is the average value across the entire weight range of 17 kg to 35 kg. However, within this weight range, the weight that caregivers actually experience most often is likely to be in the relatively lighter range, closer to 17 kg. Therefore, if we adopt the average value of 2.6 cm for the amount of sinking D that can be easily lifted at a weight of 17 kg as the minimum value D1, the preferred maximum bottom height H2 will be approximately 1 cm higher than the result of the above calculation.

[0051] In other words, if the maximum bottom height H2 is 77cm or higher, 99 percent of Japanese male caregivers (of all age groups) can comfortably provide care while wearing shoes.

[0052] Furthermore, considering cases where the thickness of the shoe heel is greater than the assumed value, where the caregiver is very tall, or where the caregiver is fatigued, it would be even more preferable if the maximum bottom height H2 could be increased by about 3 cm from the above calculation result. In other words, it would be even more preferable if the maximum bottom height H2 were 80 cm or more.

[0053] To summarize the above considerations, the most desirable maximum bottom height H1 for caregivers, in order from least desirable to most desirable, is 69cm or higher, 71cm or higher, 72cm or higher, 73cm or higher, 74cm or higher, 76cm or higher, 77cm or higher, and 80cm or higher.

[0054] Furthermore, female caregivers are generally shorter than male caregivers. Therefore, if a bed has the preferred maximum bottom height H2 described above, lowering the bottom slightly from the maximum bottom height H2 will achieve a suitable bottom height for female caregivers. The same applies to age groups not used in the above calculations.

[0055] To achieve the above preferred maximum bottom height, the preferred lifting span H3 (see Figure 2), when the minimum bottom height is 25 cm, is 44 cm or more, 46 cm or more, 47 cm or more, 48 cm or more, 49 cm or more, 51 cm or more, 52 cm or more, and 55 cm or more, in order from least preferred to most preferred. When the minimum bottom height is 30 cm, the preferred lifting span H3 is 39 cm or more, 41 cm or more, 42 cm or more, 43 cm or more, 44 cm or more, 46 cm or more, 47 cm or more, and 50 cm or more.

[0056] In order to achieve such a desirable range for the lifting span H3 as much as possible under the practical constraints described above, the bed 1 according to this embodiment has several structural improvements. These improvements will be described below with reference to Figures 7 to 11.

[0057] Figure 7 shows a longitudinal cross-sectional side view of the bed 1 according to this embodiment, showing the lifting mechanism. Figure 8 shows a perspective view of the center frame 9 viewed from below, showing the arrangement of the guide rail 59 that slides the upper end 57 on the foot side of the X-link 15 of the bed 1.

[0058] As shown in Figures 1, 7, and 8, the left and right X links 15 are connected such that the first link 15A and the second link 15B are rotatably coupled to each other via a pivot shaft 43 at their longitudinal midpoints. The head-side end (lower end) of the first link 15A is rotatably coupled to a specific point on the base frame 17 via a pivot shaft 45. The head-side end (upper end) of the second link 15B is rotatably coupled to a specific point on the center frame 9 via a pivot shaft (hidden and not visible in the figures).

[0059] The foot-side end (upper end) of the first link 15A of each X-link 15 has a roller mechanism 57, which is engaged with a horizontally extending guide rail 59 fixed to the center frame 9 so as to be movable in the length (horizontal) direction. The foot-side end (lower end) of the second link 15B also has a roller mechanism 61, which is engaged with a horizontally extending guide rail 63 fixed to the base frame 17 so as to be movable in the length (horizontal) direction.

[0060] The lower end 16A of the lifting actuator 16 (electric motor 19) is rotatably attached to the central part 27A of the support beam 27 of the base frame 17. The upper end 16B of the lifting actuator 16 (cylinder 21) is connected to a pair of left and right X links 15 so as to be able to drive them. That is, one end of a bracket 65 is fixed to one of the beams 18A of a plurality of beams 18 that connect a pair of left and right first links 15A to each other, and the upper end 16B of the lifting actuator 16 (cylinder 21) is rotatably attached to the other end of the bracket 65 via a rotating shaft 67. The fixing point of the beam 18A (bracket 65) in the longitudinal direction of the first link 15A is closer to the roller mechanism 57 at the upper end than the midpoint of the first link 15A. With this structure, when the lifting actuator 16 extends, the pair of left and right X links 15 raise the lifting frames 9, 11, and 13.

[0061] As shown in Figure 7, the height of the lower end 16A of the lifting actuator 16 (electric motor 19), which is attached to the central part 27A of the support beam 27 of the base frame 17, is lower than the height of the underside of the main girder 23 of the base frame 17. In other words, the lower end 16A of the lifting actuator 16 (electric motor 19) is positioned low enough to fit into the gap between the main girder 23 of the base frame 17 and the building floor. However, the longitudinal position of the lower end 16A of the lifting actuator 16 (electric motor 19) is near the foot end of the base frame 17, so it does not interfere with the use of the bed 1 (for example, the use of the auxiliary table mentioned above). By positioning the lower end 16A of the lifting actuator 16 (electric motor 19) as low as possible, it becomes easier to keep the pressing direction of the lifting actuator 16 within an appropriate angular range when the lifting actuator 16 (electric motor 19) pushes the first link 15A of the X link 15 to raise the lifting frames 9, 11, and 13. This contributes to minimizing the mechanical load on the lifting actuator 16.

[0062] In other words, to increase the maximum bottom height H2, it is necessary to increase the lifting span H3 of the X-link 15. Increasing the lifting span widens the range of change in the pressing direction of the lifting actuator 16. Therefore, there is a risk that the load on the lifting actuator 16 will become excessive. To mitigate this problem, it is helpful to lower the position of the lower end 16A of the lifting actuator 16 using the above configuration.

[0063] Furthermore, as shown in Figures 7 and 8, the center frame 9 has a pair of left and right main girders 69 extending in the longitudinal direction, and these two main girders 69 are connected to each other by a beam 71 extending in the width direction at a point located below the foot bottom 2D. A bracket 73 is fixed to the middle of the beam 71, extending almost downward from there. A knee-raising actuator 75 for raising the knee bottom 2C is attached to the bracket 73. A guide rail 59 for moving the roller mechanism 57 at the upper end of the aforementioned first X link 15A is fixed to the main girders 69 of the center frame 9 at a point lower than the beam 71. The guide rail 59 extends so as to intersect with the beam 71 in a three-dimensional manner. In other words, the guide rail 59 extends from the longitudinal position of the beam 71 in both the head direction and the foot direction, thereby providing the roller mechanism 57 with a sufficiently long travel distance.

[0064] The ability of the roller mechanism 57 to move along such a long distance of guide rail 59 expands the lifting span H3 by the X-link 15, making it easier to raise the maximum bottom height H2 compared to conventional beds. Furthermore, because the guide rail 59 is positioned lower than the beam 71 that supports the back-raising actuator 16, even if the guide rail 59 is long enough to intersect the beam 71, it does not interfere with or impede the support structure of the back-raising actuator 16. The positioning of the guide rail 59 lower than the beam 71 also helps to raise the maximum bottom height H2.

[0065] Figure 9 shows a side view of the lifting mechanism (X-link 15) in the bed 1 according to this embodiment when the lifting mechanism is in its lowest position.

[0066] In Figure 9, reference numeral 81 indicates the pivot point at the lower end of the first link 15A of the X-link 15, which is the center of rotation. Reference numeral 83 indicates the point of force application at the upper end of the first link 15A, which applies an upward force to the lifting frame. Reference numeral 85 indicates the pivot point at the lower end of the lifting actuator 16, which is the center of rotation. Reference numeral 87 indicates the point of force application at the upper end of the lifting actuator 16, which applies torque to the first link 15A. Reference numeral 89 indicates the foot of the perpendicular line drawn from the point of force application 87 of the lifting actuator 16 to the straight line 91 (hereinafter referred to as the "main axis" of the first link 15A) connecting the pivot point 81 to the point of application 83 of the first link 15A. Reference numeral 93 indicates the straight line connecting the fulcrum 81 of the first link 15A and the point of force application 87 of the lifting actuator 16 (hereinafter referred to as the "main axis" of the "acting arm" on which the lifting actuator 16 acts on the first link 15A). Reference numeral 95 indicates the straight line connecting the fulcrum 85 and the point of application 87 of the lifting actuator 16 (hereinafter referred to as the "main axis" of the lifting actuator 16).

[0067] As shown in Figure 9, when the lifting mechanism (X-link 15) is in its lowest position, the pivot point 85 of the lifting actuator 16 is located near the lower end of the X-link 15 (for example, the roller mechanism 61 at the lower end of the second link 15B, or the guide rail 63 that slides it) and on the longitudinal outer side (for example, the foot side). The total length P3 of the base frame 17 is preferably set within the range of 140 to 148 cm, more preferably 140 to 145 cm. The ratio P2 / P1 of the distance from the pivot point 81 of the first link 15A to the foot 89 of the perpendicular to the distance P1 from the pivot point 81 of the first link 15A to the point of force application 83 (total length of the first link 15A) is preferably set within the range of 65 to 75%. The angle Q1 between the main shaft 93 of the drive arm and the main shaft 95 of the lifting actuator 16 (hereinafter referred to as the "operating angle") is preferably set within the range of 140 to 150 degrees.

[0068] The reasons why this arrangement, dimensions, and angle setting is preferable are as follows:

[0069] First, the longer the overall length P3 of the base frame 17, the easier it is to increase the lifting span H3 and raise the maximum bottom height H2. However, in order to disassemble the bed 1 and transport it in a car (usually, the base frame 17 is the longest component among the disassembled parts), the overall length of the base frame 17 must be shorter than the length of the car's cargo area or bed. Vehicles widely used for transporting beds include so-called minivans or light vans, some of which have cargo areas or beds that are only about 150 cm long. In order to be able to load the bed into such a vehicle with a short cargo area, the overall length P3 of the base frame 17 is preferably in the range of 140 to 149 cm, and more preferably in the range of 140 to 145 cm, considering the need for sufficient thickness of packing material.

[0070] Next, the smaller the above dimensional ratio P2 / P1, the higher the maximum bottom height H2 can be, but the load on the lifting actuator 16 when pushing up the lifting frame increases, and the deflection or bouncing of the bed 1 when in use increases. Conversely, the larger the ratio P2 / P1, the less the lifting span H3 by the lifting actuator 16 of the same overall length, the lower the maximum bottom height H2 becomes, and it becomes difficult to achieve the preferred maximum bottom height H2 mentioned earlier.

[0071] To resolve this contradiction, it is preferable to set the dimensional ratio P2 / P1 within the range of 65-75%. That is, by adopting this dimensional setting, it becomes possible to suppress the deflection or bouncing of the bed 1 when the bed is in use to a level that does not pose a practical problem, while at the same time achieving the preferred lifting span H3 (e.g., about 47-52 cm) and the preferred maximum bottom height H2 (e.g., a maximum bottom height of about 72-77 cm when the minimum bottom height H1 is about 25 cm, or a maximum bottom height of about 77-82 cm when the minimum bottom height H1 is about 30 cm) as described above, under the constraint of the preferred range of 140-149 cm for the base frame 17.

[0072] Next, the smaller the operating angle Q1 is made and the closer it is to 90 degrees, the less load is placed on the lifting actuator 16, and the less the bed 1 flexes or bounces when the bed is in use. However, the orientation of the lifting actuator 16 becomes closer to vertical, so unless the overall length of the lifting actuator 16 is shortened, it becomes difficult to achieve the preferred minimum bottom height H1 mentioned earlier. Conversely, the larger the operating angle Q1 is than 90 degrees, the more load is placed on the lifting actuator 16, increasing the flexing or bounce of the bed 1 when the bed is in use. In addition, unless the overall length of the lifting actuator 16 is shortened, the overall length of the base frame 17 increases, making it difficult to set it within the preferred range of 140-149 cm (or 140-145 cm) mentioned above. On the other hand, if the overall length of the lifting actuator 16 is shortened, it becomes difficult to achieve the preferred maximum bottom height H2 mentioned earlier.

[0073] To resolve these intertwined contradictions, it is preferable to set the operating angle Q1 within the range of 140 to 150 degrees. Adopting this setting, in conjunction with the dimensional settings described above, makes it possible to suppress the deflection or bouncing of the bed 1 when the bed is in use to a level that does not pose a practical problem, while simultaneously achieving the preferred minimum bottom height H1 (e.g., about 25 cm or 30 cm), preferred lifting span H3 (e.g., about 48 cm), and preferred maximum bottom height H2 (e.g., a maximum bottom height of about 73 cm when the minimum bottom height H1 is about 25 cm, or a maximum bottom height of about 78 cm when the minimum bottom height H1 is about 30 cm).

[0074] Figure 10 shows a perspective view of the mechanism for fixing the upper end of the head side of the X-link 15 of the bed 1 according to this embodiment. Figure 11 shows a perspective view of the guide rail for sliding the upper end of the foot side of the X-link 15 of the bed 1.

[0075] As shown in Figure 10, the second link 15B of the X-link 15 has a roller mechanism 101 at its upper end. The center frame 9 has a holder 103 that extends horizontally and is shorter than the guide rail 59, near the head-side end of its main girder 69. The roller mechanism 101 of the second link 15B is housed within this holder 103. The holder 103 has an opening 105 at its foot-side end. When the bed 1 is assembled, the roller mechanism 101 is inserted into the holder 103 through the opening 105, and when the bed 1 is disassembled, it is removed from the holder 103 through the opening 105.

[0076] During the assembly of bed 1, the roller mechanism 101 is aligned with the opening of holder 103, and then the center frame 9 is moved toward the foot, pushing the roller mechanism 101 into the closed head-side end of holder 103. Then the hook 107 descends, locking the roller mechanism 101 in place at the head-side end. During the disassembly of bed 1, the hook 107 is lifted to release the lock, and then the center frame 9 is moved toward the head, moving the roller mechanism 101 out of the opening 105 of holder 103. Finally, the center frame 9 is lifted, separating the roller mechanism 101 from holder 103 (center frame 9).

[0077] As shown in Figure 11, the roller mechanism 57 at the upper end of the first link 15A is housed in a sufficiently long guide rail 59 provided near the foot-side end of the main girder 69 of the center frame 9. The guide rail 59 has an opening 109 at its foot-side end, and a stopper 111 at the foot-side end of the opening 109 that terminates the opening 109. When assembling the bed 1, the roller mechanism 57 is inserted into the guide rail 59 through the opening 109, and when disassembling the bed 1, it is removed from the guide rail 59 through the opening 109.

[0078] During the assembly of bed 1, the roller mechanism 57 is inserted into the opening 109 of the guide rail 59, and then the center frame 9 is moved toward the foot, so that the roller mechanism 57 enters the area of ​​the guide rail 59 toward the head side of the opening 109. During the raising and lowering of bed 1, the roller mechanism 57 moves horizontally back and forth within the area of ​​the guide rail 59 toward the head side of the opening 109. During the disassembly of bed 1, the center frame 9 is moved toward the head, so that the roller mechanism 57 moves to the position of the opening 109 of the guide rail 59. At this time, even if a worker accidentally tries to move the center frame 9 too far toward the head, the roller mechanism 57 will hit the stopper 111 and stop, preventing excessive movement. This prevents the failure of the roller mechanism 57 detaching from the guide rail 59 due to excessive movement, causing the center frame 9 to fall from the X-link 15. Thus, after the roller mechanism 57 reaches the position of the opening 109 in the guide rail 59, the center frame 9 is lifted, separating the roller mechanism 57 from the guide rail 59 (center frame 9).

[0079] The embodiments described above are merely illustrative examples for illustrative purposes and are not intended to limit the scope of the present invention to those embodiments only. The present invention can be implemented in various forms different from those described above. [Explanation of symbols]

[0080] 1: Bed, 2: Bottom, 9: Center frame, 11: Head frame, 13: Foot frame, 15: X-link, 15A: First link, 15B: Second link, 16: Lifting actuator, 16A: Lower end of lifting actuator, 16B: Upper end of lifting actuator, 17: Base frame, 23: Main girder of base frame, 27: Support beam, 18A: Beam, 27A: Center part of support beam, 27B: Arm part of support beam, 19: Electric motor of lifting actuator, 21: Cylinder of lifting actuator, 29: Reinforcement beam, 57: Upper end of first link (roller mechanism), 59: Guide rail, 61: Lower end of second link (roller mechanism), 63: Guide rail, 65: Bracket, 69: Main girder of center frame, 81: Pivot point of first link, 83: Point of force application of first link 85: Pivot point of the lifting actuator, 87: Point of force application of the lifting actuator, 89: Foot of the perpendicular, 91: Main axis of the first link, 93: Main axis of the working arm, 95: Main axis of the lifting actuator, 103: Holder, 105: Opening of the holder, 107: Hook, 109: Opening of the guide rail, 111: Stopper, H1: Minimum bottom height, H2: Maximum bottom height, P1: Distance from the fulcrum to the point of force application of the first link (total length of the first link), P2: Distance from the fulcrum to the foot of the perpendicular of the first link, P3: Total length of the base frame, Q1: Operating angle

Claims

1. A bed comprising a lifting mechanism, a lifting frame that can be raised and lowered by the lifting mechanism, and a bottom provided on the lifting frame, The maximum bottom height, which is the height of the top surface of the bottom when the lifting frame is at its highest height, falls within the following ranges: 69cm or taller, 71cm or taller, 72cm or taller, 73cm or taller, 74cm or taller, 76cm or taller, 77cm or taller, and 80cm or taller, It is within one of the ranges selected from among them. It is placed on the floor of the building and has a base frame that has the full length of the bed, The aforementioned lifting mechanism A pair of X-links separated from each other in the width direction of the bed, the pair of X-links that raise and lower the lifting frame, Lifting actuators that drive the pair of X-links and It has, The lower ends of the pair of X-links are attached to the base frame. Each of the pair of X-links has a first link and a second link that are connected in an X-shape so as to be rotatable to each other. The lower ends of the first and second links of the pair of X links are attached to the base frame. The pivot point at the lower end of the lifting actuator is mounted on the base frame at a position that is longitudinally outward from the lower end of the second link of the pair of X links. The point of force of the lifting actuator is coupled to the first link such that torque is applied to the first link of the pair of X links. The base frame has a pair of main girders extending in the longitudinal direction, The pair of main girders are positioned at a predetermined distance above the building floor, creating a gap between the building floor and the underside of the main girders. The lower end of the lifting actuator is positioned lower than the lower surface of the pair of main girders and fits into the gap. When the pair of X links are in their lowest position, the angle of action formed by the main axis of the working arm, which is connected in a straight line from the pivot point at the lower end of the first link to the point of force application of the lifting actuator, and the main axis of the lifting actuator, is within the range of 140 to 150 degrees. bed.

2. In the bed according to claim 1, The lifting frame has a guide rail that supports the upper end of the first link of the pair of X links so that it can move in the longitudinal direction, The guide rail has an opening for inserting and removing the upper end of the first link into the guide rail, and a stopper that terminates the opening. The aforementioned guide rail is provided below the lifting frame, and is a bed.

3. In the bed according to claim 1 or 2, A bed with a maximum bottom height of 72 cm or more.

4. In the bed according to claim 3, A bed with a maximum bottom height between 72 and 77 cm.

5. In the bed according to claim 1 or 2, A bed with a maximum bottom height of 77 cm or more.

6. In the bed according to claim 5, A bed with a maximum bottom height ranging from 77 to 82 cm.

7. In the bed according to claim 1 or 2, The difference between the highest and lowest heights of the aforementioned lifting frame, which is the lifting span, falls into the following range groups: 44cm or larger, 46cm or larger, 47cm or larger, 48cm or larger, 49cm or larger, 51cm or larger, 52cm or larger, and 55cm or larger, A bed located within one of the selected areas.

8. In the bed according to claim 7, A bed having a lifting span of 47 cm or more.

9. In the bed according to claim 8, A bed in which the aforementioned lifting span is within the range of 47 to 52 cm.

10. In the bed according to claim 1 or 2, When a perpendicular line is drawn from the point of force application of the lifting actuator to the main axis of the first link, A bed in which the ratio of the distance from the pivot point at the lower end of the first link to the foot of the perpendicular to the total length of the first link is within the range of 65 to 75%.

11. In the bed according to claim 10, A bed in which the total length of the base frame is within the range of 140 to 149 cm.

12. In the bed according to claim 11, The base frame has a support beam near one end of the base frame in the longitudinal direction, which connects the pair of main girders to each other. The support beam has a substantially V-shape that is recessed toward one end in the longitudinal direction and toward the downward direction, A bed in which the lower end of the lifting actuator is attached to the most recessed central part of the substantially V-shaped support beam.

13. In the bed according to claim 12, A bed in which the base frame has reinforcing beams connecting the pair of main girders to each other at locations near the support beams.

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