Abstract:
To provide a cuff for a blood pressure monitor having a curled elastic member which is easily attached to an arm, does not make the subject feel pain when attached, and exhibits a characteristic of excellent fitting. 
     A curled elastic member  1 A has one end portion  12  extending outward so as to enwind the other end portion  11  inward. Specifically, from the other end portion  11  to a position where the other end portion  11  is mutually opposite, the radius of curvature gently increases. From the mutually opposite portion to the one end portion  12,  the radius of curvature largely increases.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     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. 
     2. Description of the Related Art 
     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.    
     However, the curled elastic member  92  as shown in FIG. 13A has the following problems 1 to 3. 
     1. Operation of uncurling the curled elastic member  92  to be attached on an arm is not easy. 
     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. 
     2. The end portions of the curled elastic member  92  cut into the flesh of the arm. 
     In the case of the curled elastic body  92  having the sectional shape of complete round, when it is attached around the arm, the edges of the discontinuous portion  92   a  cut into the flesh of the arm and the subject often feels pain. Particularly, in the case of a big arm, such a tendency is conspicuous. 
     3. The shape of the curled elastic member  92  cannot be altered according to the size and shape of an arm such as slender arm, big arm, tapered arm (arm of which size changes largely from the shoulder to the elbow), straight arm (arm of which size changes little from the shoulder to the elbow) or the like, so that the curled elastic member  92  is not easily fit to an arm. 
     This is because the thickness of the curled elastic member  92  is uniform and the sectional shape thereof is a complete round. Although the size and shape of an arm vary widely with the individual, the curled elastic member  92  does not have a form which can be easily fit to every one. 
     On the other hand, a curled elastic member having increased fitness which can be attached to an arm more easily has been proposed as shown in FIG. 13B (Japanese Unexamined Patent Publication No. 61-238229 (1987)). This curled elastic member  92 ′ is formed so that its thickness gradually increases from the both ends (discontinuous portion  92 ′ a ) toward the center portion and, accordingly, the rigidity gradually increases. The thickness and rigidity are the maximum in the center portion. 
     However, even in the curled elastic member  92 ′, since the thickness is simply gradually increased from the both ends toward the center portion, the shape is not flexibly altered to be adapted to various arms, and it has room for improvement. A provision of a curled elastic member having more excellent performance is awaited. 
     SUMMARY OF THE INVENTION 
     The present invention has been achieved by paying attention to such conventional problems and circumstances and an object of the present invention is to provide a cuff for a blood pressure monitor having a curled elastic member which can be easily attached to an arm, does not make the subject feel pain when attached, and exhibits the characteristic of excellent fitness. 
     In order to achieve the above-mentioned object, a cuff for a blood pressure monitor of the present invention having therein a bladder and a curled elastic member disposed on the outside of the bladder to hold a ring shape of the cuff, wherein one end portion of the curled elastic member is extended outward so as to enwind the other end portion inward. 
     In the curled elastic member, at the time of attachment to an arm, the one end portion extended outward is thrown over the arm, and the curled elastic member can be put on the arm while being largely uncurled. That is, the operation of uncurling the curled elastic member and the operation of attaching the curled elastic member to an arm can be simultaneously performed, so that the operation of attachment to an arm is easy. Since the curled elastic member has such a form that the one end portion is longer than the other end portion and the other end portion is enwinded inward, the end portions do not easily cut in the flesh of an arm when attached, so that the subject does not feel pain. 
     According to another embodiment of the curled elastic member, a sectional shape of the curled elastic member is approximately triangle and one end portion of the curled elastic member is extended. By the curled elastic member as well, equivalent action and effects can be obtained. 
     According to further another embodiment, the curled elastic member has a narrow portion in which width in the axial direction of an arm is partly narrowed or a thin portion in which thickness is partly reduced between an approximately center portion in the circumferential direction of the arm and both end portions. In this case, the elasticity and alteration in the shape can be adjusted by the narrow portion or the thin portion. That is, by the narrow portion or the thin portion, the curled elastic member (i.e., the cuff) gets easily to be twisted. Thus, the curled elastic member is fit more easily to an arm of any shape such as a straight arm or tapered arm. 
     Moreover, the narrow portion or thin portion is not provided as the both end portions of the curled elastic member, so that the rigidity of the both end portions is not reduced and an arm can be securely held by the both end portions. Furthermore, by not particularly providing the narrow portion as the both end portions of the curled elastic member, as compared with the case where the both end portions are narrowed, the subject does not have strange feeling such that the both end portions cut into the flesh of the arm. 
     In the case of the form in which the curled elastic member has the narrow portion, although the form may be used satisfactorily, it is preferable to construct a portion missed by narrowing the width to form the narrow portion by a thin portion which is thinner than the narrow portion. This is because that if the portion missed by the narrow portion exists, when the bladder is inflated, it is feared that the bladder is inflated from the side (missing portion) of the narrow portion 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 blood pressure cannot be measured stably. 
     The configuration in which the missing portion generated due to the narrow portion is formed as the thin portion aims at obtaining an effect such that, while maintaining fitness by the both end portions, the curled elastic member is easily twisted so as to be fit to any of arms of various shapes such as straight arm or tapered arm. 
     The narrow portion may have a constant width in the circumferential direction of an arm or a width gradually reduced from the center portion toward both end portions. 
     According to further another embodiment, an inner circumferential face of the curled elastic member may have an approximately round shape and an outer circumferential face of the curled elastic member may have an approximately polygon shape. In other words, the curled elastic member has a sectional shape such that the round inner circumferential face is inscribed in the polygonal outer circumferential face (strictly, it is not inscribed). The curled elastic member is thick at corner portions of the polygon and is thin in the side portions. Therefore, the form in which the thickness of the curled elastic member is substantially changed is obtained. In a manner similar to the curled elastic member having the portion of which shape is altered, the shape can be altered in correspondence with variations in arms. The curled elastic member does not easily cut in the flesh of an arm and has an excellent fitness to an arm. 
     A curled elastic member having the structure quite different from that of the above-mentioned curled elastic member may be also used. The curled elastic member is formed by connecting a plurality of elastic pieces by hinges, and energizing means for energizing the elastic member in a direction of uncurling the elastic member when the elastic member is uncurled at a predetermined angle or more, and energizing the elastic member in a direction of curling the elastic member when the elastic member is curled at a predetermined angle or less is provided on the hinged portions of the respective elastic pieces. 
     In the curled elastic member, the energizing force to the uncurling direction and the energizing force to the curling direction are given by the energizing means rather than the elasticity of the elastic pieces. The energizing force changes by using uncurling of the elastic member at a predetermined angle as a branch point. That is, when the elastic member is largely uncurled at the time of attachment to an arm, it is automatically largely uncurled by the energizing means. When the elastic member is curled at the time of fixing to the arm, it is automatically curled by the energizing means and fits to the arm. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     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; 
     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; 
     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; 
     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; 
     FIGS. 5A and 5B are a perspective view and an exploded view, respectively, of a curled elastic member according to further another embodiment; 
     FIGS. 6A and 6B are a perspective view and an exploded view, respectively, of a curled elastic member according to further another embodiment; 
     FIGS. 7A and 7B are a perspective view and an exploded view, respectively, of a curled elastic member according to further another embodiment; 
     FIGS. 8A and 8B are a perspective view and a sectional view, respectively, of a curled elastic member according to further another embodiment; 
     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; 
     FIG. 11 is a perspective view showing a general cuff; 
     FIG. 12 is a sectional view showing the inside of the cuff of FIG. 11; and 
     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. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will be described below on the basis of embodiments. However, the present invention is characterized by a curled elastic member in a cuff for a blood pressure monitor. Since the structure of the cuff may be an ordinary one shown in FIG. 12, the curled elastic member will be mainly described below. The description of the action of the curled elastic member is applied as it is to the cuff having the curled elastic member. 
     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. 
     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.  2 B). 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.  3 A), the curled elastic member  1 A is put on the arm  80  (FIG.  3 B). 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. 
     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. 
     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. 
     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. 
     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. 
     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. 
     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. 
     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 ID (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. 
     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. 
     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 an arm is partly narrowed between an approximately center portion  31 ′ in the circumferential direction of an arm and both end portions  15  and  16 , and the portion missed by narrowing the width to form the narrow portion  31  is a thin portion  32  which is thinner than the narrow portion  31 . 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  exists so as to fill the portion missed by narrowing the width to form the narrow portion  31 . 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. 
     In order to provide the thin portion  32  in the portion missed by narrowing the width to form the narrow portion  31 , for example, separately 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. 
     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. 
     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. 
     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. 
     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. 
     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. 
     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.  10 A). 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.  10 B). However, the curled elastic member  1 G is usually in the closed state as shown in FIG.  10 B. 
     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. 
     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.