Abstract:
A vital sign detection device is mounted on the wrist of a subject for measurement of vital sign such as pulse wave and blood pressure and has a regulating portion for restricting the movement of the hand during a measurement. The regulating portion extends from a main body of the device toward the distal end of the hand, and may be a plate integral with the main body or the main body itself moved toward the distal end. When the device is used for the detection of pulse waves, the plate may have a band for tying the hand to the plate for preventing rotation of the wrist joint. When the device is used for the measurement of blood pressure, the main body of the device, which is slidably or rotatably transported toward the distal end, may suppress the movement of hand enough to prevent the rise of wrist tendons from hindering the measurement.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a vital sign detection device configured to be mounted on a wrist of a subject for vital sign detection, especially to a wrist pulse wave detection device and a wrist blood pressure monitor.  
           [0003]    2. Description of the Related Art  
           [0004]    Vital sign detection, which is performed on a wrist of a subject of the detection, is known to be susceptible to hand movement. This applies to both measuring the pulse wave itself and measuring the blood pressure through the detection of the pulse wave. For example, the detection of a pulse wave of the artery at the wrist is performed by pressing a pressure sensing unit on the palm side of the wrist. If the movement of the hand is not restricted during detection period, the joint of the wrist is free to move, resulting in a noise generation. Furthermore, the pressure applied through the sensing unit on the wrist varies depending on the angle between the hand and the arm. Variation in that pressure results in an unexpected change in the amplitude of the measured pulse wave. One of the proposed solutions to this problem is to use a supporting member for restricting the movement of hand, which is mounted on the wrist portion separately and prior to the mounting of the main body of the pulse wave detection device having the sensing unit (Japanese Laid Open Patent Publication No. Hei 11-33007). However, mounting both the main body and the supporting member separately makes preparation for pulse wave detection bothersome, and requires a complicated structural design of a whole detection unit.  
           [0005]    On the other hand, a pressure sensing unit of a wrist blood pressure monitor, which is provided between an air bag and a deflation valve, detects air pressure value and a pulse wave combined in the varying air pressure during deflation of compressed air from the air bag. If a hand used for blood pressure detection is significantly bent toward its palm side, the tendon at the wrist portion protrudes near the skin, pushing the artery deep under the skin. This results in insufficient pressurizing of the detection portion and, thus, an inaccurate detection. It is noted, however, that pulse wave detection requires more rigorous restriction of the movement of hand so as not to generate noises, while blood pressure detection needs only to restrict the inward movement of the hand so as not to hinder the detection.  
         SUMMARY OF THE INVENTION  
         [0006]    The embodiments of this invention are directed to a vital sign detection device which has a simple structure for easy mounting and yet provides vital signs with a high accuracy by restricting the movement of hand.  
           [0007]    This invention provides a vital sign detection device configured to be mounted on a wrist of a subject having a main body, a pressure sensing unit for sensing a pulse wave, a pressurizing unit for applying pressure to a detection portion of the wrist, a cuff configured for mounting the main body on the palm side of the wrist; and a regulating portion for restricting movement of the hand. This regulating portion extends from the main body toward the distal end of the hand and is placed on the palm side of the hand. Since the main body and the regulation portion are mounted on the wrist at the same time, this configuration assures an easy and secure mounting of the device on the wrist.  
           [0008]    In one embodiment in which the invention provides a pulse wave detection device, the regulating portion is a plate extending from the main body, either on the palm side or the back side of the hand. The device may have plates on both sides. A band may be attached to one of the plates for further restricting the movement of the hand. There may be a hole in the band for inserting a finger. When mounting the device on a wrist, a person can hold onto the band by inserting a finger into the hole while adjusting the position of the device without any help from others. A positioning mark may be formed on the plate or the band for an accurate positioning of the fingers. Since the tendon on which the main body should be placed is aligned with the middle finger, an accurate positioning of the finger results in an accurate positioning of the main body.  
           [0009]    In another embodiment in which the invention provides a blood pressure monitor, the regulating portion is the main body itself or a part of the main body, which is moved by a moving mechanism toward the distal portion of the hand. This movement of the main body may activate the device for operation. This configuration eliminates a need for an operation-activation switch from the main body, resulting in a larger top surface area of the main body available for other purposes including information display. The regulating portion may also be a guide portion formed as a part of the main body, which can be extended toward the distal end of the hand for further restricting the movement of the hand. The guide portion may be detached from the main body.  
           [0010]    This invention also provides a vital sign detection device configured to be mounted on a wrist of a subject having a main body, a pressure sensing unit for sensing vital sign, a pressurizing unit for pressing the pressure sensing unit on a detection portion of the wrist, a cuff configured for mounting the main body on the palm side of the wrist and a regulating portion for restricting movement of the hand. This regulating portion extends along the direction of the hand and comprises two parts integral to each other, which are adjustable so that the length of the regulating portion is adjusted according to the size of the hand. The regulating portion may be provided on either side of the hand, or on both sides. A band may be attached to one or both of the regulating portions.  
           [0011]    This invention further provides a vital sign detection device configured to be mounted on a wrist of a hand having a main body, a pressure sensing unit for sensing vital sign, a pressurizing unit for pressing the pressure sensing unit on a detection portion of the wrist and a plate extending from the main body toward the distal end of the hand. The plate is bent toward the back side of the hand, and includes at least a battery, a display unit, an operation unit, a circuit board or a compressed air manipulation system. The plate may have a storage area for containing the battery, the circuit board or the compressed air manipulation system. This configuration allows the size and weight reduction of the main body as well as the restriction of hand movement. It also achieves a better weight balance of the device, which results in an easier mounting. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a perspective view of a pulse wave detection device of a first embodiment of the invention.  
         [0013]    [0013]FIG. 2 is a perspective view of a clip portion used with the first embodiment of FIG. 1.  
         [0014]    [0014]FIG. 3 is a perspective view of a pulse wave detection device of a second embodiment of the invention.  
         [0015]    [0015]FIG. 4 is a cross-sectional view of the device of FIG. 3.  
         [0016]    [0016]FIG. 5 is a schematic view of a pulse wave detection device of the second embodiment mounted on a wrist.  
         [0017]    [0017]FIG. 6 is a schematic view of a pulse wave detection device mounted on a wrist of a third embodiment of the invention.  
         [0018]    [0018]FIG. 7 is a schematic view of a pulse wave detection device mounted on a wrist of a fourth embodiment of the invention.  
         [0019]    [0019]FIG. 8 is a schematic view of a pulse wave detection device mounted on a wrist of a fifth embodiment of the invention.  
         [0020]    [0020]FIG. 9 is a schematic view of a pulse wave detection device mounted on a wrist of a sixth embodiment of the invention.  
         [0021]    [0021]FIG. 10 is a schematic view of a pulse wave detection device mounted on a wrist of a seventh embodiment of the invention.  
         [0022]    [0022]FIG. 11 is a perspective view of a pulse wave detection device of an eighth embodiment of the invention.  
         [0023]    [0023]FIG. 12 is a cross-sectional view of the device of FIG. 11.  
         [0024]    [0024]FIG. 13 is a schematic view of a pulse wave detection device having components of the device consolidated in a main body.  
         [0025]    [0025]FIG. 14 is a perspective view of a blood pressure monitor having common elements of the embodiments as blood pressure monitor of the invention.  
         [0026]    [0026]FIG. 15 is a schematic cross-sectional view when the device of FIG. 14 is mounted on a wrist.  
         [0027]    [0027]FIG. 16 shows a posture when a hand is bent toward its palm side.  
         [0028]    [0028]FIG. 17 is a schematic cross-sectional view of the wrist portion of the hand bent toward the palm side as shown in FIG. 16.  
         [0029]    [0029]FIG. 18 is a schematic side view of a blood pressure monitor mounted on a wrist of a ninth embodiment of the invention.  
         [0030]    [0030]FIG. 19 is a schematic side view of the device of FIG. 18 in which the main body of the device is moved toward the distal end of the hand.  
         [0031]    [0031]FIG. 20 is a schematic side view of a blood pressure monitor mounted on a wrist of a tenth embodiment of the invention.  
         [0032]    [0032]FIG. 21 is a schematic plan view of the device of FIG. 20 mounted on the wrist.  
         [0033]    [0033]FIG. 22 is a schematic plan view of a blood pressure monitor mounted on a wrist as an eleventh embodiment of the invention.  
         [0034]    [0034]FIG. 23 is a schematic plan view of the device of FIG. 22 in which a guide portion is extended toward the distal end of the hand.  
         [0035]    [0035]FIG. 24 is a schematic side view of a blood pressure monitor mounted on a wrist as a twelfth embodiment of the invention.  
         [0036]    [0036]FIG. 25 is a schematic side view of the device of FIG. 24 in which a guide portion is rotated out toward the distal end of the hand.  
         [0037]    [0037]FIG. 26 is a schematic plan view of the device of FIG. 25. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0038]    The embodiments of this invention will be described with reference to the drawings described above. FIG. 1 is a perspective view of a pulse wave detection device as a first embodiment of this invention. The pulse wave detection device  1  includes a pressure sensing unit  2 , which is in contact with a detection portion of a subject&#39;s body (such as the palm side of a wrist) during detection, an air bag  3 , which presses the pressure sensing unit  2  on the detection portion, a clip portion  4 , which covers the air bag  3  from the outside, and a band  5 , which is used as a cuff for mounting the device on the wrist. This band  5  carries or contains the pressure sensing unit  2 , the air bag  3 , and the clip portion  4 .  
         [0039]    The clip portion  4 , as shown in FIG. 2, includes a cylindrical clip base  4   a  with an opening along its longitudinal direction, and a plate  4   b,  which extends from one end of the clip base  4   a  and bends toward the central axis of the cylinder of the cylindrical clip base  4   a.  The clip base  4   a  is covered by the band  5 , while the plate  4   b  is exposed without any cover. The portion of the plate  4   b  next to the clip base  4   a  is a simple extension of the surface of the cylinder of the clip base  4   a,  but the top portion of the plate  4   b  is bent toward the central axis of the cylinder of the clip base  4   a.  Surface fasteners  6 ,  7  are mounted on both ends of the band  5  so that the band  5  is fastened when the device is worn on a wrist.  
         [0040]    This pulse wave detection device has a main body  1   a,  which includes the pressure sensing unit  2 , air bag  3 , clip base  4   a  and the portion of the band  5  which carries or contains the aforementioned components of the device. The plate  4   b  extends from the clip base  4   a  toward the distal end of the hand of the subject wearing the pulse wave detection device  1 .  
         [0041]    The configuration of this embodiment, as well as of the other embodiments of this invention described below, makes it easier to mount the device on a wrist because of the unitary combination of the main body  1   a  and the device for restricting the movement of a hand (plate  4   b ), and yet ensures an accurate and stable detection of pulse wave.  
         [0042]    [0042]FIG. 3 is a perspective view of a pulse wave detection device of a second embodiment of this invention, and FIG. 4 is a cross-sectional view of the device shown in FIG. 3 through the plane indicated by the arrow in FIG. 3. The portion denoted by reference numeral  4   c  corresponds to the clip base  4   a  of the first embodiment shown in FIG. 1 and forms a casing for the main body  1   a  of the pulse wave detection device. A plate  4   b  extends from the casing  4   c  toward the distal end of a hand wearing the pulse wave detection device and bends toward back side of the hand. The size and the shape of the plate  4   b  are essentially the same as the plate shown in FIGS. 1 and 2. One end of a band  5   a  is fixed to the casing  4   c  of the main body  1   a  through an axis  8  of the casing  4   c,  and the other end of the band  5   a  has a surface fastener  7 , which engages with a surface fastener  9  mounted on the casing  4   c.    
         [0043]    The pulse wave detection device of the second embodiment is mounted on a wrist of a subject so that the plate  4   b  is, as shown in FIG. 5, in direct contact with the palm (A) side of the hand through a proper adjustment of the band  5   a  and the fasteners  7 ,  9 . The rotation of the wrist joint is restricted during detection, since the main body  1   a  and the plate  4   b  hinder the movement of the hand relative to the wrist portion. Similarly, the pulse wave detection device of the first embodiment shown in FIG. 1 should be mounted on the wrist of a subject so that the plate  4   b  is in direct contact with the palm side of the subject&#39;s hand.  
         [0044]    [0044]FIG. 6 is a schematic view of a pulse wave detection device of a third embodiment of this invention. A plate  4   b  extends from the main body  1   a  toward the distal end of the hand, and bends toward the back (B) side of the hand. Although it is not shown in FIG. 6, plate  4   b  is connected to and supported by the main body  1   a.  The pulse wave detection device of the third embodiment is mounted on the wrist so that the plate  4   b  is in direct contact with the back side of the hand.  
         [0045]    [0045]FIG. 7 is a schematic view of a pulse wave detection device of a fourth embodiment of this invention. This device has two plates  4   b   1 ,  4   b   2 , extending toward the distal end of the hand. Plate  4   b   1  on the back (B) side of the hand extends from the band  5   a,  and  4   b   2  on the palm (A) side extends from the main body  1   a.  The device is mounted on the wrist so that plate  4   b   1  is in direct contact with the back side of the hand and plate  4   b   2  is in direct contact with the palm of the hand. This configuration ensures more stable detection of the pulse wave because the movement of the hand is restricted by the two plates  4   b   1 ,  4   b   2  on both sides of the hand.  
         [0046]    [0046]FIG. 8 is a schematic view of a pulse wave detection device of a fifth embodiment of this invention. This device includes a band  10 , which is connected to the plate  4   b  at its distal end and is used for tying the palm or fingers to the plate  4   b,  in addition to the band  5   a  used for mounting the device on the wrist. When a subject wears the device of the fifth embodiment on his or her wrist, the subject or another person first temporarily mounts the main body la of the pulse wave detection device on the wrist so that the plate  4   b  is in direct contact with the palm (A) of the hand on which the band  5   a  is mounted, then adjusts the position of the plate  4   b  relative to the hand, ties the palm or fingers to the plate  4   b  using the band  10 , and finally tightly mounts the device on the wrist. In this fifth embodiment, the movement of the hand and the rotation of the wrist joint are further restricted because the hand is tied to the plate  4   b  using the belt  10 .  
         [0047]    [0047]FIG. 9 is a schematic view of a pulse wave detection device of a sixth embodiment of this invention. This device includes a marking  11  for positioning the fingers, which is formed on the upper surface of the plate  4   b  at its distal end. The plate  4   b  extends from the main body  1   a  and has the marking along the center line of the plate  4   b.  When the marking  11  coincides with the center line of the middle finger of the hand, as shown in FIG. 9, the pressure sensing unit  2  is placed at or near the artery of the wrist for pulse wave detection. This configuration ensures pulse wave detection of high accuracy by adjusting the mounting of the main body  1   a  with the band  5   a  so that the marking  11  lies on the line running through the center of the middle finger.  
         [0048]    [0048]FIG. 10 is a schematic view of a pulse wave detection device of a seventh embodiment of this invention. As in the case of the fifth embodiment, this device includes a band  10  which is connected to the plate  4   b  at its distal end and is used for tying the palm or fingers to the plate  4   b,  in addition to the band  5   a  used for mounting the device on the wrist. Similarly, the movement of the hand and thus the rotation of the wrist joint are further restricted with the hand being fixed to the plate  4   b.  In this embodiment, one end of the band  10  is fixed on the upper surface of the plate  4   b  at its distal end. A marking  11  is formed for the alignment of the middle finger, and serves the same purpose as the marking  11  of the sixth embodiment shown in FIG. 9.  
         [0049]    As shown in FIG. 10, the band  10  of the seventh embodiment has a hole  12  for receiving the thumb when the band  10  is wrapped around the hand for tying it to the plate  4   b.  When a subject of detection wears this device, he or she first puts the main body  1   a  on the wrist so that the plate  4   b  is in direct contact with the palm (A) of the hand, puts the thumb through the hole  12 , grabs the plate  4   b  with the thumb through the hole  12 , and adjusts the alignment between the marking  11  and the middle finger so that a proper positioning of the device relative to the hand is secured by fastening the two bands  5   a,    10 . This configuration of the seventh embodiment ensures a reliable mounting of the pulse wave detection device even when the subject of detection wears the device by itself.  
         [0050]    As one modification of the embodiments (1-7) described above, the plate  4   b  and clip base  4   a  may be formed as two separate parts and integrally combined through a slide mechanism and fixation by a screw or other fastening structure. In this configuration, it is possible to adjust the length of the plate  4   b  in accordance with the size of the hand of a subject of detection.  
         [0051]    [0051]FIG. 11 is a perspective view of a pulse wave detection device of a eighth embodiment of this invention, and the FIG. 12 is a perspective view of the device shown in FIG. 11 cut along a direction parallel to the longitudinal direction of the device.  
         [0052]    [0052]FIG. 13 shows a pulse wave detection device in which batteries  21 , a display unit  22 , an operation unit  23 , a circuit board  24  and a compressed air manipulation system  25  including a pump and a pressure control valve are consolidated within the main body  1   a.  In this configuration, the size and weight of the main body  1   a  inevitably increase and thus result in a difficulty of mounting the device on the wrist because of an improper weight balance of the device and a high center of gravity position of the device. The portion indicated by the thick line in FIG. 13 is the core of the device housing only the pressure sensing unit  2  and a pressurizing unit such as an air bag  3 .  
         [0053]    The eighth embodiment of this invention shown in FIGS. 11 and 12 is intended to solve the difficulty described in conjunction with the pulse wave detection device shown in FIG. 13. In the eighth embodiment, the plate  4   b  of the clip portion  4  is formed as a casing having a storage area  26  for storing batteries  21 , a circuit board  24  and a compressed air manipulation system  25 . An operation unit  23  is formed on the top surface of the plate  4   b.  The plate  4   b  of this embodiment may be the plate  4   b  of the second embodiment or any other embodiment described above. A display unit  22  is formed on the top surface of the main body  1 , though it may be formed on the top surface of the plate  4   b  as well.  
         [0054]    This configuration reduces the size and weight of the main body  1   a  by disposing in the plate  4   b  all or a part of the components of the device described above, including the butteries  21 , the display unit  22 , the operation unit  23 , the circuit board  24  and the compressed air manipulation system  25 . As a result, the ease of mounting the device on a wrist improves because of the improved weight balance of the device.  
         [0055]    [0055]FIG. 14 shows common components of blood pressure monitors described below as embodiments of this invention. A wrist blood pressure monitor  100 E includes a main body  101  containing a control device for controlling the blood pressure detection, and a cuff  102  for mounting the main body  101  on a wrist. The main body  101  has a display unit  103  and a start switch  104  on its top surface, and, as shown in FIG. 15, contains a pressure sensing unit  220 , a pump  222  for compressing the air, a deflation valve  224  and a CPU for controlling these components of the blood pressure monitor.  
         [0056]    The cuff  102  is a band  110  which has an air bag  109  therein for receiving compressed air sent form the pump  222  contained in the main body  101  and for pressurizing the artery of wrist during blood pressure detection. The band also has a surface fastener  111  for fastening the band  110  around the wrist.  
         [0057]    In the blood pressure detection, the pressure sensing unit  220  does not directly touch the wrist for detecting the pulse wave of the artery as is the case with the pulse wave detection device described above. Rather, the pressure sensing unit  220  of the blood pressure monitor is placed between the air bag  109  and the deflation valve  224 . For measuring blood pressure, the air bag  109  is first filled with compressed air from the pump  222  for pressurizing the wrist portion until the artery is closed, the pumping is then stopped, and the deflation valve  224  is controlled by the CPU for slowly deflating the air bag  109 . During the release of the air from the air bag  109 , the pressure sensing unit  220  detects the pressure of the air bag  109 , which is a combination of the air pressure and pressure due to the pulse wave. The CPU derives the pulse wave component from the total pressure measured, and finds a maximum blood pressure when the pulse wave appears and a minimum blood pressure when the pulse wave disappears. As a modification, it is also possible to find the maximum and minimum blood pressure during the pressurization of the air bag  109  in a converse fashion.  
         [0058]    [0058]FIG. 15 shows a cross-sectional view of the blood pressure monitor  100 E of FIG. 14, which is mounted on a wrist and has the air bag  109  filled with the compressed air for the detection. The main body  101  of the blood pressure monitor  100 E contains a pump  222  for generating the compressed air, a deflation valve  224 , and a pressure sensing unit  220 . The band  110  is fastened so that the air bag  109  is placed over the radialis  205  of the wrist portion for properly pressurizing the radialis  205  during detection.  
         [0059]    Also shown in the figure are the radius  202  on the thumb side of the cross section, the ulna  203  on the little finger side, flexor digitorum profundus  204   a,  palmaris longus  204   b,  flexor digitorum superficialis  206   a,  flexor carpi ulnaris  206   b,  and the ulnaris  207 .  
         [0060]    If a hand is bent toward its palm side, as shown in FIG. 16, the tendons of the wrist move toward the skin as shown in FIG. 17. Especially, the palmaris longus  204   b  and the flexor carpi ulnaris  206   b  rise in a large amount enough to push the skin upward. On the other hand, the radialis  205  and the ulnaris  207  are pushed down into the muscles. As a result, when a hand is bent toward its palm side during blood pressure detection, it is difficult to properly apply the pressure of the air bag  109  to the radialis  205  or the ulnaris  207  because of the tendons rising toward the skin. Accordingly, accurate detection of blood pressure is not achieved.  
         [0061]    The following embodiments of this invention are directed to solving the aforementioned problem. FIG. 18 is a schematic side view of a blood pressure monitor  100 A mounted on a wrist as a ninth embodiment of this invention, and FIG. 19 is a schematic side view of the blood pressure monitor  100 A in which the main body of the device is moved toward the distal end of the hand.  
         [0062]    The wrist blood pressure monitor  100 A of the ninth embodiment has a main body  101  which is slidably mounted on a cuff  102 . The mechanism for moving the main body  101  toward the distal end of the hand (the direction of the arrow S in FIG. 19) is a slide rail  101   a  provided between the main body  101  and the cuff  102 . It is also possible to use other slide mechanism known in the art including linear bearings to replace the slide rail  101   a  as a means for moving the main body  101  in this embodiment.  
         [0063]    The main body  101 , when moved toward the distal end of the hand as shown in FIG. 19, serves as a regulating portion for restricting the movement of the hand. The range of motion of the hand is smaller when the main body  101  is moved (A 2  in FIG. 19) than it is when the main body  101  is positioned on the cuff (A 1  in FIG. 18). As a result, more accurate application of the air bag pressure to the artery is achieved when the main body is moved toward the distal end and thus prevents the hand from bending toward its palm side enough to allow the tendons to hinder blood pressure detection, for example.  
         [0064]    [0064]FIG. 20 is a schematic side view of a blood pressure monitor  100 B mounted on a wrist as a tenth embodiment of the invention, and FIG. 21 is a schematic plan view of the blood pressure monitor  100 B of FIG. 20 mounted on the wrist of a subject.  
         [0065]    The wrist blood pressure monitor  100 B of the tenth embodiment has a guide portion  120  extending toward the distal end of the hand. This guide portion  120  may be made of a plastic material such as ABS or polypropylene, and may be connected to either the main body  101  or the cuff  102 .  
         [0066]    The guide portion  120  serves as a regulating portion for restricting the movement of the hand. As a result, more accurate application of the air bag pressure to the artery is achieved because the guide portion  120  prevents the hand from bending toward its palm side enough to allow the tendons to hinder detection. The guide portion  120  may be detachably mounted on the blood pressure monitor  100 B, or it may be retractable into the blood pressure monitor  100 B itself. Either configuration improves the handling of the blood pressure monitor  100 B during its mounting on and detaching from the wrist.  
         [0067]    [0067]FIG. 22 is a schematic plan view of a blood pressure monitor  100 C mounted on a wrist as an eleventh embodiment of the invention, and FIG. 23 is a schematic plan view of the device of FIG. 22 in which a guide portion  120  is extended toward the distal end of the hand.  
         [0068]    The wrist blood pressure monitor  100 C of the eleventh embodiment has a guide portion  120  which is the same as the guide portion  120  of the tenth embodiment. However, the guide portion  120  of the eleventh embodiment is extended toward the distal end of the hand based on a slide mechanism in synchronization with the slide movement of the main body  101  toward the distal end. The slide mechanism of the ninth embodiment may be used in the eleventh embodiment. The blood pressure monitor  100 C also has a switching mechanism which activates the blood pressure monitor  100 C when the main body  101  is moved toward the distal end of the hand. The switching mechanism may be based on a pair of a detent and a projection formed between main body  101  and slide mechanism  101   a.  The engagement of the detent and the projection, for example, switches on the blood pressure monitor  100 C, and disengagement of the detent and projection switches off the device. Alternatively, the engagement may switch off the device and the disengagement switch on the device. Other switching mechanisms known in the art may be applied to this embodiment.  
         [0069]    The guide portion  120 , which extends toward the distal end of the hand in synchronization with the slide movement of the main body  101 , serves as a regulating portion for restricting the movement of the hand. As a result, more accurate application of the air bag pressure to the artery is achieved because the guide portion  120  prevents the hand from bending toward its palm side enough to allow the tendons to hinder the detection.  
         [0070]    Furthermore, the blood pressure monitor  100 C of the eleventh embodiment, which is switched on for the detection only when the main body  101  is moved toward the distal end of the hand, ensures that the regulating portion for restricting the movement of the hand (the main body  101  or the guide portion  120 ) is always in place during the detection of blood pressure. In addition, this configuration eliminates the need for a start switch mounted on the top surface of the main body  101 , and thus makes it possible to have a larger display unit on the top surface of the main body  101  for better display of the information on the display unit, including measured blood pressure values.  
         [0071]    Although the wrist blood pressure monitor of the eleventh embodiment has both the slide mechanism for the guide portion  120  in synchronization with the slide movement of the main body  101  and the switching mechanism in synchronization with the same movement, each of the two mechanisms may be provided separately for a blood pressure monitor.  
         [0072]    [0072]FIG. 24 is a schematic side view of a blood pressure monitor  100 D mounted on a wrist as a twelfth embodiment of the invention, and FIG. 25 is a schematic side view of the blood pressure monitor  100 D of FIG. 24 in which a guide portion is rotated out toward the distal end of the hand. FIG. 26 is a schematic plan view of the blood pressure monitor  100 D of FIG. 25.  
         [0073]    The main body  101  of the wrist blood pressure monitor  100 D of the eleventh embodiment can be rotated out toward the distal end of the hand from the cuff  102 . The rotating mechanism of the twelfth embodiment is a rotation axis  130  provided between the main body  101  and the cuff  102 . As shown in FIG. 25, the main body  101  is swung around the rotation axis  130  in the direction of R shown in the figure.  
         [0074]    The main body  101 , when rotated out toward the distal end of the hand as shown in FIG. 25, serves as a regulating portion for restricting the movement of the hand. The range of motion of the hand is smaller when the main body  101  is rotated out (A 2  in FIG. 25) than it is when the main body  101  is positioned on the cuff (Al in FIG. 24). As a result, more accurate application of the air bag pressure to the artery is achieved when the main body is moved toward the distal end and prevents the hand from bending toward its palm side enough to allow the tendons to hinder the detection.  
         [0075]    The features described above of the embodiments of the blood pressure monitor of this invention may be selectively combined to provide a wrist blood pressure monitor. Furthermore, although the whole main body is moved toward the distal end in the above embodiments, only a portion of the main body may be moved and a similar effect may be obtained for restricting the movement of the hand.  
         [0076]    Although the embodiments are divided into those of a pulse wave detection device and those of a blood pressure monitor, the features described for the pulse wave detection device may be applicable to the blood pressure meter, and those for the blood pressure meter may be applicable to the pulse wave detection device, as long as the features meet the requirements of restricting the movement of hand of a particular device. For example, the plate for restricting the movement of hand of the first embodiment as a pulse wave detection device of this invention may be detachably mounted on the main body for the ease of mounting the device on the wrist, or may be extended toward the distal end of the hand for a better restriction of the movement of hand. Likewise, a wrist blood pressure meter may have a plate extending from the main body for properly restricting the movement of hand for an accurate detection.  
         [0077]    The above is a detailed description of particular embodiments of this invention. It is recognized that departures from the disclosed embodiments may be made within the scope of the invention and that obvious modifications will occur to a person skilled in the art. The full scope of the invention is set out in the claims that follow and their equivalents. Accordingly, the claims and specification should not be construed to narrow the full scope of protection to which the invention is entitled.