Abstract:
The invention provides a variety of cuff design for blood pressure monitor, which assures an easy and firm fitting to an arm of a patient. Specifically, the curled elastic member of the cuff is overlapped at both end portions for easy fitting. The rigidity and thickness of the curled elastic member are designed to follow the shape of the upper arm of the patient, which significantly varies in size depending on the location of the arm.

Description:
[0001]    This application is a continuation-in-part of Ser. No. 10/047,994, filed Jan. 17, 2002. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a cuff for a blood pressure monitor and, more particularly, to a cuff characterized by a curled elastic member disposed on the outside of a bladder to hold a ring form of the cuff.  
           [0004]    2. Description of the Related Art  
           [0005]    As shown in FIG. 11 (perspective view) and FIG. 12 (sectional view), a cuff for a blood pressure monitor has generally a configuration such that a bladder  91  and a curled elastic member  92  are provided in a cloth bag  90 . A tube  93  is connected to the bladder  91 , and a velcro fastener  94  is attached on the outside of the cloth bag  90 . The curled elastic member  92  is disposed on the outside of the bladder  91  to hold the cuff in a ring form by its elasticity. As shown in FIG. 13A, the curled elastic member  92  has an uniform thickness and has a sectional shape of a complete round in which a part thereof is a discontinuous portion  92   a.    
           [0006]    However, the curled elastic member  92  as shown in FIG. 13A has the following problems  1  to  3 .  
           [0007]    1. Operation of uncurling the curled elastic member  92  to be attached on an arm is not easy.  
           [0008]    Since the sectional shape is a complete round, the curled elastic member  92  has to be uncurled and then attached on an arm. Specifically, in order to uncurl the curled elastic member  92 , it has to be pulled with some strength. The user needs some experience to attach the elastic member  92  in the uncurled state onto his/her arm.  
           [0009]    2. When the curled elastic member  92  is attached around an arm, the edges of the discontinuous portion  92   a  of the curled elastic member cut into the flesh of the arm due to its elastic force so that users in particular with thick arm often feel pain.  
           [0010]    3. Since the curled elastic member  92  has uniform thickness and the sectional shape thereof is complete round, it cannot deform so as to correspond to a person with thick arm or a person with thin arm and hence is difficult to fit such arms.  
           [0011]    For addressing the above described problems, Japanese Laid-open Patent Publication No. S61-238229 (1986) proposes a curled elastic member  92 ′ as shown in FIG. 13B. This curled elastic member  92 ′ is so configured that its thickness gradually increases in a circumferential direction of an arm from the both ends toward the center portion. Hence the rigidity of the curled elastic member  42  gradually increases. The thickness and rigidity are the maximum at the center portion.  
           [0012]    This curled elastic member  92 ′ has somewhat solved the aforementioned problems. However, for an arm whose diameter changes to a large extent depending on the part of the arm, in other words, for a largely-inclined arm, such as an upper arm whose diameter is small in the vicinity of the elbow but gradually increases toward the shoulder, the curled elastic member  92 ′ fits the large diameter part of the arm while leaving a clearance with respect to the small diameter part of the arm. As described above, the curled elastic member  92 ′ cannot sufficiently deform to correspond to the shape of the arm.  
           [0013]    The present invention is directed to solving the above-mentioned problems associated with conventional cuffs for a blood pressure monitor. It is an object of the present invention to provide a cuff for a blood pressure monitor with excellent fitting ability which can fit various shapes of arms, in particular, largely-inclined arms.  
         SUMMARY OF THE INVENTION  
         [0014]    The invention provides a cuff for a blood pressure monitor, which includes a bladder and a curled elastic member disposed on the outside of the bladder to hold a ring shape of the cuff. The curled elastic member has at least two different rigidities in an axial direction of the ring shape.  
           [0015]    The cuff may be configured to be attached on an arm of a patient, and the curled elastic member may have a higher rigidity of the two different rigidities in a portion of the curled elastic member that is positioned at a thin portion of the arm when the cuff is attached on the arm, and may have a lower rigidity of the two different rigidities in a portion of the curled elastic member that is positioned at a thick portion of the arm when the cuff is attached on the arm. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1A is a perspective view of a curled elastic member according to an embodiment, provided for a cuff for a blood pressure monitor, and FIG. 1B is a perspective view showing a state where the curled elastic member is attached on an arm;  
         [0017]    [0017]FIGS. 2A and 2B are perspective views showing a first step and a second step, respectively, of attaching the curled elastic member of FIGS. 1A and 1B onto an arm;  
         [0018]    [0018]FIG. 3A is a perspective view showing a third step of attaching the curled elastic member of FIGS. 1A and 1B onto an arm, and FIG. 3B is a perspective view showing an attached state;  
         [0019]    [0019]FIG. 4A is a perspective view of a curled elastic member according to another embodiment, and FIG. 4B is a perspective view showing a state where a cuff having the curled elastic member is attached on an arm;  
         [0020]    [0020]FIGS. 5A and 5B are a perspective view and an exploded view, respectively, of a curled elastic member according to further another embodiment;  
         [0021]    [0021]FIGS. 6A and 6B are a perspective view and an exploded view, respectively, of a curled elastic member according to further another embodiment;  
         [0022]    [0022]FIGS. 7A and 7B are a perspective view and an exploded view, respectively, of a curled elastic member according to further another embodiment;  
         [0023]    FIGS.  7 C- 7 F are a perspective view, an exploded view and two cross-sectional view, respectively, of a modification of the embodiment of FIGS. 7A and 7B;  
         [0024]    FIGS.  7 G- 7 I are a perspective view, an exploded view and a cross-sectional view, respectively, of another modification of the embodiment of FIGS. 7A and 7B;  
         [0025]    [0025]FIG. 7J is a schematic exploded view of a modification of the curled elastic member of FIGS.  7 G- 7 I.  
         [0026]    [0026]FIGS. 8A and 8B are a perspective view and a sectional view, respectively, of a curled elastic member according to further another embodiment;  
         [0027]    [0027]FIG. 9 is a perspective view of a curled elastic member according to further another embodiment;  
         [0028]    [0028]FIGS. 10A and 10B are side views of the curled elastic member in an uncurled state and in a curled state, respectively;  
         [0029]    [0029]FIG. 11 is a perspective view showing a general cuff;  
         [0030]    [0030]FIG. 12 is a sectional view showing the inside of the cuff of FIG. 11; and  
         [0031]    [0031]FIG. 13A is a perspective view of a curled elastic member according to a conventional technique, disposed in the cuff of FIG. 11 and FIG. 13B is a perspective view of a curled elastic member according to another conventional technique. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0032]    The present invention will be described below on the basis of embodiments. It is to be noted that the cuff for a blood pressure monitor in the present invention has its feature in a curled elastic member thereof, and structural features and its operation of the cuff except the curled elastic member may be those of conventional cuffs shown in FIG. 11. Accordingly, the following explanation focuses on the curled elastic member.  
         [0033]    [0033]FIG. 1A is a perspective view of a curled elastic member, according to an embodiment, provided for a cuff for a blood pressure monitor, and FIG. 1B is a perspective view when the curled elastic member is attached to an arm. One end  12  of this curled elastic member  1 A is extended outward so as to enwind the other end  11  inward. That is, from the other end  11  to the mid portion of the curled elastic member where the other end  11  meets the curled elastic member, the radius of curvature of the curled elastic member gently increases. From the mid portion of the curled elastic member to the one end  12 , the radius of curvature largely increases.  
         [0034]    A method of attaching the curled elastic member  1 A around an arm  80  will be described by referring to FIGS. 2A and 2B and FIGS. 3A and 3B. First, in FIG. 2A, the one end portion  12  as a longer one of the curved elastic member  1 A is thrown over the arm  80 . In this state, while uncurling the curled elastic member  1 A, it is pulled to the side opposite to the one end portion  12  (FIG. 2B). The curled elastic member  1 A is further pulled until the width of the uncurled width becomes about equal to that of the arm  80  (FIG. 3A), the curled elastic member  1 A is put on the arm  80  (FIG. 3B). The curled elastic member  1 A is then fit to the arm  80  by its elasticity. In such a manner, the curled elastic member  1 A, i.e., the cuff is attached on the arm.  
         [0035]    When the curled elastic member  1 A is used, the operation of uncurling the curled elastic member  1 A and the operation of attaching the curled elastic member  1 A onto the arm  80  can be simultaneously performed, so that the operation of attaching the curled elastic member  1 A onto the arm  80  is easy. Since the one end portion  12  is longer than the other end portion  11  and the other end portion  11  is enwinded inward, when the curled elastic member  1 A is attached on the arm  80 , the other end portion  11  and the one end portion  12  do not easily cut into the arm  80 , and the subject does not feel pain.  
         [0036]    [0036]FIG. 4A is a perspective view of a curled elastic member according to another embodiment. This curled elastic member  1 B has a sectional shape of approximately triangle and has an extended one end portion  14 . The curled elastic member  1 B can be attached onto the arm  80  in a manner similar to the above-mentioned curled elastic member  1 A. That is, the one end portion  14  which is the longer one of the curled elastic member  1 B is thrown over the arm  80 , the curled elastic member  1 B is pulled to be uncurled and put on the arm  80 . Consequently, the operation of uncurling the curled elastic member  1 B and the operation of attaching the curled elastic member  1 B on the arm  80  can be simultaneously performed.  
         [0037]    When the curled elastic member  1 B whose sectional shape is approximately triangle is attached on the arm  80 , as shown in FIG. 4B, a gap is formed between each of the corners and the arm  80 . However, the bladder  91  is inflated so as to fill the gap by injection of air, so that the action of pressing the arm  80  with the bladder  91  is not hindered. The sectional shape of the curled elastic member  1 B may be, besides approximately triangle, quadrangle or polygon.  
         [0038]    [0038]FIGS. 5A and 5B are a perspective view and an exploded view, respectively, of a curled elastic member according to further another embodiment. This curled elastic member  1 C has a narrow portion  26  in which a width in the axial direction of an arm is partly narrowed between a center portion  26 ′ in the circumferential direction of the arm and both end portions  25 . The narrow portion  26  has a width gradually decreased from the center portion  26 ′ towards the both end portions  25 . In the curled elastic member  1 C, the rigidity of the narrow portion  26  is reduced. Thus, the curled elastic member  1 C (i.e., a cuff) gets easily to be twisted, so that it easily fits to an arm of any shape such as a straight arm or tapered arm.  
         [0039]    Since the both end portions  25  of the curled elastic member  1 C are not formed as the narrow portion  26 , the rigidity of the both end portions  25  does not deteriorate, and the arm can be securely held by the both end portions  25 . Further, by not making the both end portions  25  as the narrow portion  26 , as compared with a case where the both end portions  25  are also formed as the narrow portion  26 , the subject does not have strange feeling such that the both end portions  25  cut into the flesh of the arm.  
         [0040]    [0040]FIGS. 6A and 6B are a perspective view and an exploded view, respectively, of a curled elastic member according to further another embodiment. This curled elastic member  1 D has a narrow portion  21  in which a width in the axial direction of an arm is partly narrowed between an approximately center portion  24  in the circumferential direction of the arm and both end portions  22  and  23 . The narrow portion  21  has a fixed width in the circumferential direction of the arm. The approximately center portion  24  does not have a fixed width but is tapered in correspondence with an arm which is generally tapered from the shoulder side toward the elbow side. Therefore, at the time of attachment onto an arm, the wider side of the center portion  24  has to be set on the shoulder side. The user has to see the direction of the curled elastic member  1 D when it is set in the cloth bag  90  of the cuff. Further, one end portion  23  is extended outward so as to enwind the other end portion  22  inward.  
         [0041]    In the curled elastic member  1 D, in a manner similar to the curled elastic member  1 C, the rigidity of the narrow portion  21  is reduced. Consequently, the curled elastic member  1 D (i.e., the cuff) gets easily to be twisted, so that it easily fits to an arm of any shape such as a straight arm or tapered arm.  
         [0042]    Since the both end portions  22  and  23  of the curled elastic member  1 D are not formed as the narrow portion  21 , the rigidity of the both end portions  22  and  23  does not deteriorate, and the arm can be securely held by the both end portions  22  and  23 . Further, by not making the both end portions  22  and  23  as the narrow portion  21 , as compared with a case such that the both end portions  22  and  23  are also formed as the narrow portion  21 , the subject does not feel strange such that the both end portions  22  and  23  cut into the flesh of the arm. Obviously, at the time of attachment to an arm, the one end portion  23  which is the longer one is thrown over the arm.  
         [0043]    [0043]FIGS. 7A and 7B are a perspective view and an exploded view, respectively, of a curled elastic member according to further another embodiment. This curled elastic member  1 E has a narrow portion  31  in which a width in the axial direction of the ring shape of the cuff is partly narrowed between an approximately center portion  31 ′ in the circumferential direction of the ring shape of the cuff and both end portions  15  and  16 . A thin portion  32  which is thinner than the narrow portion  31  is provided at the remainder of the curled elastic member. The narrow portion  31  has a width which gently increases and decreases from the end portions  15  and  16  toward the center portion  31 ′. The thin portion  32  and the narrow portion  31  provide a substantially rectangular elastic member when it is uncurled. Consequently, the curled elastic member  1 E as a whole has a fixed width. The one end portion  16  is extended outward so that the other end portion  15  is enwinded inward.  
         [0044]    In order to provide the thin portion  32 , for example, the thin portion  32  as a separate member may be joined to the narrow portion  31  or the portion  32  other than the narrow portion  31  may be formed thin by cutting, integral molding or the like at the time of making the whole curled elastic member  1 E. The planar shape pattern of the narrow portion  31  is not limited to that shown in the drawing but, for example, the pattern of the narrow portion  21  in the curled elastic member  1 D in FIG. 6 may be used.  
         [0045]    The curled elastic member  1 E is obtained by improving the curled elastic member  1 D. That is, in the case of the form where the portion missed by the narrow portion  31  exists, when the bladder is inflated, it is feared that the bladder is inflated from the side (missing portion) of the narrow portion  31  to the surface side of the cuff so that the arm cannot be sufficiently pressed, and there is also the possibility such that, in a process of taking blood pressure data while changing air pressure, noise occurs due to inflation from the missing portion to the outside of the bladder, so that there is the possibility that blood pressure cannot be measured stably.  
         [0046]    However, by forming the missing portion generated due to the narrow portion  31  as the thin portion  32 , while maintaining the effects of the curled elastic member  1 D, the possibilities of the above-mentioned problems can be also eliminated. That is, by forming the curled elastic member  1 D so as to be fit to any of arms of various shapes by the both end portions and so as to be easily twisted, an effect such that the curled elastic member can be easily fit to an arm of any shape such as a straight arm or tapered arm is obtained.  
         [0047]    [0047]FIGS. 7C and 7D are a perspective view and an exploded view of a curled elastic member provided for a cuff for a blood pressure monitor, according to the first modification of the embodiment of FIGS. 7A and 7B. A section view viewed from the right direction along the line A-A′ of FIG. 7D is shown in FIG. 7E. A curled elastic member  101  is formed of a resin such as PP (polypropylene), and includes two regions having different thicknesse, i.e., a thin portion  102  and a thick portion  103 . When the curled elastic member  101  is attached around an arm, it is wounded so that one end portion  104  is placed inside another end portion  105 . Attention is now directed to an axial direction of the ring shape of the cuff, or the direction of an arm when the curled elastic member  101  is attached on the arm. It can be seen that one end of the cylindrically wound curled elastic member  101  forms the thin portion  102  and the other end forms the thick portion  103 . The thick portion  103  has high rigidity so that it can firmly grip the arm, whereas the thin portion  102  has low rigidity so that it can easily deform in conformance with the shape of the arm in contrast to the thick portion  103 . Consequently, when the curled elastic member  101  is oriented so that the thick portion  103  corresponds to the arm part of small diameter and the thin portion  102  corresponds to the arm part of large diameter, and the curled elastic member  101  is wound so that no clearance is left between the thick portion  103  and the arm part of small diameter, the thin portion  102  deforms to closely follow the shape of the arm part of large diameter. As a result, it can be attached around the entire circumference of the arm without leaving any clearance.  
         [0048]    In the first modification, the rigidity of the curled elastic member  101  is varied in two steps. However, the curled elastic member may have more than two rigidities, or may change the rigidity continuously by, for example, gradually changing the thickness in the axial direction of ring shape of the cuff from the one end side to the other end side as shown in FIG. 7F.  
         [0049]    [0049]FIGS. 7G and 7H are a perspective view and an exploded view showing a curled elastic member provided for a cuff for a blood pressure monitor, according to the second modification of the embodiment of FIGS. 7A and 7B. A section view viewed from the right direction along the line B-B′ of FIG. 7H is shown in FIG. 71. A curled elastic member  111  includes two regions having different thickness, i.e., a thin portion  112  and a thick portion  113 . When the curled elastic member  111  is attached around an upper arm, it is wounded so that the thin portion  112  is located on the shoulder side and one end portion  114  is placed inside another end portion  115 . Attention is now directed to an axial direction of the ring shape of the cuff, or the direction of an arm when the curled elastic member  111  is attached on the arm. It can be seen that the part corresponding to the shoulder side forms the thin portion  112  and the part corresponding to the elbow side forms the thick portion  113 . Accordingly, as is the case with the first modification, when the thick portion  113  having high rigidity is wound around the arm part near the elbow where the diameter is smaller than that of the part on the shoulder side so as not to leave a clearance, the thin portion  112  having a lower rigidity deforms to closely follow the shape of the arm part on the shoulder side where the diameter is larger than that of the elbow side. As a result, it can be attached around a largely-inclined arm without leaving any clearance.  
         [0050]    Next, attention is directed to a circumferential direction the ring shape of the cuff, or the direction around the arm when the curled elastic member  101  is attached on the arm. It can be seen that on either side of a hole  116 , through which a tube connected to a bladder (not shown) is to be inserted into the curled elastic member  111 , is provided a narrow portion  117 ,  118  where the width of the thick portion  113  along the axial direction of is partially narrowed. These narrow portions  117 ,  118  can conform to arms having various inclination angles and enables attachment while ensuring higher fitting ability since the rigidity along the axial direction of the curled elastic member  111  is low in these narrow portions  117 ,  118  and hence the curled elastic member  111  can easily twist.  
         [0051]    Furthermore, in the vicinity of the hole  116  is formed a wide portion  119  where the width of the thick portion  113  along the axial direction is larger than those of the thin portions, whereby the rigidity is set higher so as to reduce the deformation during application of pressure to the arm by the bladder. Furthermore, the curled elastic member has two different end portions, i.e., one end portion  114  and the other end portion  115 . The one end portion  114  and its vicinity are formed as the thin portion  112 , and the other end  115  and its vicinity are formed as the thick portion  113 . When the cured elastic member is wound around an upper arm, the one end portion  114 , which is designed to be wound inside and come into contact with the arm, will conform to the shape of the arm to reduce the pain of the subject for blood pressure measurement since it has a low rigidity. The other end potion  15  will ensure close attachment to the arm since it has high rigidity.  
         [0052]    In order to form a curled elastic member having non-uniform rigidity, for example, the thin portion  112  and the thick portion  113  may be integrally formed to make the curled elastic member  111  or the part corresponding to the thin portion  112  may be formed by cutting from a member having the entire shape of the curled elastic member  111  and having the thickness of the thick portion  113 . Also, a member having a shape of the part corresponding to the thick portion  113  may be bonded on a member having the entire shape of the curled elastic member  111  formed in a thickness of the thin portion  112 . In this configuration, it is effective to use materials of different rigidities such that the member having the entire shape is formed of a material of low rigidity and the member having a shape of the part corresponding to the thick portion  113  is formed of a material of high rigidity, for example.  
         [0053]    The pattern of the thin portion  112  and the thick portion  113  shown in FIG. 7H does not limit the pattern design used in this embodiment.  
         [0054]    [0054]FIG. 7J shows an exploded view showing a curled elastic member  121  provided for a cuff for a blood pressure monitor, according to a further modification of the second modification of the embodiment of FIGS. 7A and 7B. In this configuration, the rigidities along the axial and circumferential directions of the ring shape of the cuff are changed by effecting a punching (boring) process on the material. Specifically, a part  122  which is intended to have a low rigidity corresponding to the thin portion  112  in the curled elastic member  111  of the second modification is subjected to a punching (boring) process to provide a plurality of holes (or bores)  124 , while a part  123  which is intended to have a high rigidity corresponding to the thick part  113  is subjected to neither punching nor boring process. As a result, the entire thickness of the curled elastic member  121  is uniform, while the rigidity is not uniform in the axial and circumferential directions, which allows desired rigidity distribution for conforming to the shape of the arm. Accordingly, as is the case with the second modification, the curled elastic member  121  can be closely attached around any arms having a variety of shapes and degrees of inclination.  
         [0055]    The positions, size and population of the holes may be adjusted to provide more effective attaching characteristics of the curled elastic member. For example, the size of the bore or hole is not necessarily identical among them, but large and small bores or holes may exist together. Although either punching or boring process is effected in this embodiment, processes for making holes and bores may be effected in combination.  
         [0056]    [0056]FIGS. 8A and 8B are a perspective view and a sectional view of a curled elastic member according to further another embodiment. This curled elastic member  1 F is formed so that its inner circumferential face  1   a  is an approximately round shape and an outer circumferential face  1   b  has a polygon shape (approximately hexagon herein). With the structure, the corner portions of the polygon become thick portions  35  and the side portions become thin portions  36 . Therefore, the form in which the thickness is changed is obtained as a result. Particularly, in a manner similar to the curled elastic members  1 C to  1 E, the shape can be altered according to variations in the arm, and the curled elastic member does not easily cut in the arm and fits the arm very well. Obviously, since the one end portion  28  is extended outward than the other end portion  27 , the curled elastic member is easily attached on the arm.  
         [0057]    [0057]FIG. 9 is a perspective view of a curled elastic member according to further another embodiment. FIGS. 10A and 10B are side views of the curled elastic member in an uncurled state and in a curled state, respectively. This curled elastic member  1 G is formed by connecting a plurality of (three herein) elastic pieces  41 ,  42 , and  43  by hinges. Two coil springs  50  as energizing means are attached to the respective hinged portions. The elastic pieces  41  and  43  serve as both end portions, and the elastic piece  42  serves as a center portion. The elastic piece  41  is set longer than the elastic piece  43  so that an end  43   a  of the elastic piece  43  is enwinded inward.  
         [0058]    Three hinges as the hinged portions are provided between the elastic pieces  41  and  42 , and between the elastic pieces  42  and  43 . The elastic pieces  41  to  43  can relatively swing around a spindle  55  of each hinged portion as a fulcrum. The coil springs  50  are attached to supporting portions  51  provided at facing ends of the elastic pieces  41  to  43 . In each of the elastic pieces  41  to  43 , a notch (to which no reference numeral is designated) for receiving the coil spring  50  is formed.  
         [0059]    When the curled elastic member  1 G is uncurled by a predetermined angle or more, the coil spring  50  is energized in the direction of uncurling the curled elastic member  1 G. When the curled elastic member  1 G is curled by a predetermined angle or less, the coil spring  50  is energized in the direction of curling the curled elastic member  1 G. That is, as obvious from FIGS. 10A and 10B, when the coil spring  50  is positioned on the outer side than the spindle  55  as a fulcrum of each of the elastic pieces  41  to  43 , the energizing force acts in the direction of uncurling the curled elastic member  1 G (FIG. 10A). When the coil spring  50  is positioned on the inner side than the spindle  55 , the energizing force acts in the direction of curling the elastic member  1 G (FIG. 10B). However, the curled elastic member  1 G is usually in the closed state as shown in FIG. 10B.  
         [0060]    When the curled elastic member  1 G is attached on an arm, the end portion  41   a  of the long elastic piece  41  is thrown over the arm and, in such a state, the curled elastic member  1 G is uncurled outward at a predetermined angle or more. By the energizing force of the coil spring  50 , the curled elastic member  1 G naturally enters a maximum uncurled state. When the elastic member  1 G is set in a predetermined region of an arm and is curled at a predetermined angle or more, the elastic member  1 G is naturally curled by the energizing force of the coil spring  50 , and is fit to the arm with a proper pressing force.  
         [0061]    As described above, the cuff for the blood pressure monitor of the present invention has the curled elastic member in a peculiar form. Consequently, the cuff can be easily attached to an arm. When the cuff is attached to an arm, the end portions do not easily cut in the flesh of the arm, so that the subject does not feel pain. The shape of the cuff can be altered in correspondence with variations in arms, so that the cuff fits to an arm excellently.