Patent Publication Number: US-2021164596-A1

Title: Hose clamp

Description:
TECHNICAL FIELD 
     The present invention relates to a hose clamp used for connecting pipings of an automobile by using a hose, for example. 
     BACKGROUND ART 
     In the related art, in connecting pipings of an automobile by using a hose, a method is widely used in which a flexible hose is put on outer peripheries of end portions of pipings having a pipe shape and further an outer periphery of the hose is fastened with a hose clamp, thereby fixing the hose to the pipings. 
     For example, the following Patent Literature 1 discloses a hose band that has a hose band body bent in a substantially cylindrical shape and a first tab piece and a second tab piece provided at both ends of the hose band body. On both sides of the hose band body, narrow portions formed at substantially the same width are provided at positions in point symmetry, and a first locking claw extending inward in a thumb shape is formed on an inner side of one narrow portion and a second locking claw extending inward in a little finger shape is formed on an inner side of the other narrow portion (see paragraph [0011]). When the first locking claw and the second locking claw are engaged with each other, the hose band body is in a state where a diameter of the hose hand body is expanded, and when engagement between the first locking claw and the second locking claw is released, the hose band body is in a state where the diameter of the hose band body is reduced and the hose is fastened and fixed. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP-A-H10-318474 
     SUMMARY OF INVENTION 
     Technical Problem 
     In the hose band of Patent Literature 1, since the first locking claw and the second locking claw protrude respectively from the inner sides of the narrow portions provided on both sides of the hose band body that is to surround an outer periphery of a hose, a relatively large gap is formed between the inner side of one narrow portion and the inner side of the other narrow portion in a state where the locking claws are engaged with each other (see FIG. 7 of Patent Literature 1). The gap between the inner sides of the narrow portions is maintained even when the hose band body is in the state where the diameter of the hose band body is reduced after the engagement between the locking claws is released. As a result, a portion (portion fastened and fixed by the hose band body and the pair of narrow portions) to which a fastening pressure by the hose band made of metal greatly applies and a portion (gap portion between inner sides of the narrow portions) to which no fastening pressure applies, are generated and a surface pressure by the hose band becomes non-continuous. At the portion to which no fastening pressure applies, a fastening and fixing force for the hose and the pipe may decrease and performance of sealing between the hose and the pipe may decrease. 
     Accordingly, an object of the present invention is to provide a hose clamp that is capable of improving performance of sealing between a hose and a piping, pipe, or the like connected to the hose when the hose clamp is in a state where a diameter of the hose clamp is reduced. 
     Solution to Problem 
     In order to achieve the above object, the present invention provides a hose clamp, including: a plate spring body that is curved in an annular shape and that is to be attached so as to surround an outer periphery of a hose; and a pair of tab portions that are provided at both end portions of the plate spring body in a circumferential direction. A diameter of the plate spring body is reduced when the pair of tab portions are separated from each other and is expanded when the pair of tab portions are brought close to each other. The plate spring body has a base portion that extends by a predetermined length along a circumferential direction of the hose, a first arm portion that extends from one side of the base portion in an axial direction at one end side of the base portion in a circumferential direction, and a second arm portion that extends from the other side of the base portion in the axial direction at the other end side of the base portion in the circumferential direction. A first overlap portion and a second overlap portion are formed at tip end sides of the first arm portion and the second arm portion in an extending direction respectively. In a state where the diameter of the plate spring body is reduced, the first overlap portion and the second overlap portion are configured so as to overlap with each other in the circumferential direction of the plate spring body and, as viewing the plate spring body from a radial direction, not to overlap with each other in an axial direction of the plate spring body. The pair of tab portions are bent and extend outward in the radial direction of the plate spring body, from tip ends of the first arm portion and the second arm portion in the extending direction. Engagement portions are provided on facing surfaces of the pair of tab portions respectively, the engagement portions holding the plate spring body in a state where the diameter of the plate spring body is expanded when the pair of tab portions are brought close to each other in the circumferential direction and are brought close to each other in the axial direction. As viewing the plate spring body from the radial direction, the engagement portions are provided in the tab portions, at positions closer to side edge portions being opposite to facing side edge portions of the overlap portions of the first arm portion and the second arm portion than to the facing side edge portions, respectively. 
     Advantageous Effects of Invention 
     According to the hose clamp of the present invention, a structure can be implemented in which engagement portions that maintain the plate spring body in the state where the diameter of the plate spring body is expanded are provided on the pair of tab portions, and the engagement portions do not exist on the arm portions of the plate spring body. At the same time, a structure can be implemented in which the engagement portions are provided on the tab portions, at positions closer to the side edge portions being opposite to the facing side edge portions of the overlap portions of the arm portions than to the facing side edge portions, and the engagement portions do not protrude from the facing side edge portions of the overlap portions. Therefore, when a diameter of the plate spring body is reduced, the overlap portions of the arm portions can be disposed close to each other in the axial direction of the plate spring body, so that a gap between the facing inner side edge portions of the overlap portions can be reduced, and the performance of sealing between the hose fastened and fixed by the hose clamp and a pipe or the like can be improved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view illustrating a first embodiment of a hose clamp in a state where a diameter of the hose clamp is reduced according to the present invention. 
         FIG. 2  is a perspective view of the hose clamp in a state where the diameter of the hose clamp is reduced in a case of being viewed from a direction different from that in  FIG. 1 . 
         FIG. 3  is a perspective view of the hose clamp in a state where the diameter of the hose clamp is expanded. 
         FIG. 4  is a developed view of the hose clamp. 
         FIG. 5  is a front view of the hose clamp in a state where the diameter of the hose clamp is reduced. 
         FIG. 6  is a plan view of the hose clamp in a state where the diameter of the hose clamp is reduced. 
         FIG. 7  is a perspective view of the hose clamp in a state where the diameter of the hose clamp is expanded. 
         FIG. 8A  is a perspective view taken along an arrow A in  FIG. 7 . 
         FIG. 8B  is a perspective view taken along an arrow B in  FIG. 7 . 
         FIG. 9  is a front view of the hose clamp in a state where the diameter of the hose clamp is expanded. 
         FIG. 10  is a plan view of the hose clamp in a state where the diameter of the hose clamp is expanded. 
         FIG. 11  is a cross-sectional view taken along a line D-D in  FIG. 9 . 
         FIG. 12  is a side view of the hose clamp in a state where the diameter of the hose clamp is expanded. 
         FIG. 13  is an illustrative plan view illustrating a state where a diameter of the hose clamp is about to be expanded from a state where the diameter of the hose clamp is reduced. 
         FIG. 14  is a perspective view for illustrating other shape of a pair of tab portions in the hose clamp. 
         FIG. 15  is an enlarged perspective view of a main part of a hose clamp in a state where the diameter of the hose clamp is expanded according to a second embodiment of the present invention. 
         FIG. 16A  is an enlarged plan view of a main part of a first tab portion of the hose clamp. 
         FIG. 16B  is an enlarged plan view of a main part of a second tab portion of the hose clamp. 
         FIG. 17  is an enlarged perspective view of a main part of a hose clamp in a state where the diameter of the hose clamp is expanded according to a third embodiment of the present invention. 
         FIG. 18A  is an enlarged plan view of a main part of a first tab portion of the hose clamp. 
         FIG. 18B  is an enlarged plan view of a main part of a second tab portion of the hose clamp. 
         FIG. 19  is an enlarged perspective view of a main part of a hose clamp in a state where the diameter of the hose clamp is expanded according to a fourth embodiment of the present invention. 
         FIG. 20A  is an enlarged plan view of a main part of a first tab portion of the hose clamp. 
         FIG. 20B  is an enlarged plan view of a main part of a second tab portion of the hose clamp. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, a first embodiment of a hose clamp according to the present invention will be described with reference to  FIGS. 1 to 14 . 
     For example, various types of pipings are arranged inside an automobile or the like, and a flexible hose made of a material such as rubber is employed to connect these pipings. As illustrated in  FIG. 1 , a hose clamp  10  (hereinafter, referred to as “clamp  10 ”) of the present invention is disposed on an outer periphery of a hose  5  covering one end portion of a piping  1  such as a pipe or a tube, and is used for fixing the hose  5  to the piping  1  by fastening the outer periphery of the hose  5 . 
     As illustrated in  FIG. 1 , the clamp  10  according to this embodiment is formed by punching a band-like metal plate as illustrated in  FIG. 4  into a predetermined shape and bending the metal plate. The clamp  10  has a plate spring body  20  that is curved in an annular shape and that is to be attached so as to surround the outer periphery of the hose  5 , a first tab portion  40  that is provided at one end portion of the plate spring body  20  in a circumferential direction thereof, and a second tab portion  50  that is provided at the other end portion of the plate spring body  20  in the circumferential direction. The plate spring body  20  and the pair of tab portions  40  and  50  are integrally formed of a metal material such as stainless steel or spring steel. 
     As illustrated in  FIGS. 1 to 4 , the plate spring body  20  has a base portion  21  that extends by a predetermined length along the circumferential direction of the hose  5 , a first arm portion  23  that extends from one side in an axial direction F (see  FIG. 4 ) at one end side in a circumferential direction E (see  FIG. 4 ) of the base portion  21 , and a second arm portion  25  that extends from the other side in the axial direction F at the other end side in the circumferential direction E of the base portion  21 . In other words, the arm portions  23  and  25  are provided at positions that are point-symmetrical with respect to a center C (see  FIG. 4 ) of the base portion  21 . The axial direction F of the base portion  21  is a direction (also referred to as a width direction) orthogonal to the circumferential direction E of the base portion  21 , and means the same direction as a direction along an axial center of the hose  5  or the piping  1  fastened and fixed by the clamp  10 . In addition, the circumferential direction E and the axial direction F are the same for the plate spring body  20  and the pair of tab portions  40  and  50 . 
     The plate spring body  20  is in a free state where a diameter of the plate spring body  20  is reduced when the pair of tab portions  40  and  50  are separated, as illustrated in  FIGS. 1, 2, 5 , and the like, and expands in diameter against an elastic force when the pair of tab portions  40  and  50  are brought close to each other, as illustrated in  FIGS. 3, 9 , and the like. 
     As illustrated in  FIG. 4 , the first arm portion  23  and the second arm portion  25  extend at a constant width that is narrower than a length from a side edge portion  21   a  of the base portion  21  to a central line L (line along a center of the base portion  21  in the axial direction F). Further, the arm portions  23  and  25  extend from the base portion  21  with the same width. As illustrated in  FIG. 4 , outer edge portions  23   a  and  25   a  of the arm portions  23  and  25  are linearly continuous (on the same plane) with respect to both side edge portions  21   a  and  21   a  of the base portion  21  so as not to have a step, a notch, or the like. 
     Further, in the base portion  21 , tapered portions  22  where the base portion  21  narrows gradually are formed on the other side in the axial direction F in one end side in the circumferential direction E, and on one side in the axial direction F in the other end side in the circumferential direction E. The tapered portions  22  relax an abrupt change in stress distribution from the base portion  21  to arm portions  23  and  25 . 
     Although the arm portions  23  and  25  in this embodiment are formed with the same width, for example, one arm portion may be formed to be narrower or wider than the other arm portion, as long as the arm portions may be provided within a range of a plate width (length along the axial direction F) of the base portion. 
     In addition, a first overlap portion  27  and a second overlap portion  29  are formed at tip end sides in an extending direction of the first arm portion  23  and the second arm portion  25 , respectively. Further, as illustrated in  FIG. 5 , in a free state where the diameter of the plate spring body  20  is reduced, the first overlap portion  27  and the second overlap portion  29  are configured such that the tip end sides of the first arm portion  23  and the second arm portion  25  in the extending direction overlap with each other in the circumferential direction E of the plate spring body  20  as viewing the plate spring body  20  from the axial direction F (see  FIG. 1 ), and such that as illustrated in  FIG. 6 , the tip end sides of the first arm portion  23  and the second arm portion  25  in the extending direction do not overlap with each other in the axial direction F of the plate spring body  20  as viewing the plate spring body  20  from a radial direction R (see  FIG. 5 ). The radial direction refers to a direction directing from a radially outer side of the clamp toward an axial center of the clamp, or a direction directing from the axial center of the clamp toward the radially outer side of the clamp. 
     In the free state where the diameter of the plate spring body  20  is reduced, as illustrated in  FIG. 6 , the overlap portions  27  and  29 , which overlap with each other in the circumferential direction of the plate spring body  20  and do not overlap with each other in the axial direction F, are displaced in the axial direction F of the plate spring body  20  and are arranged adjacent to each other so that inner side edge portions  27   a  and  29   a  thereof (facing side edge portions) face each other. The inner side edge portions  27   a  and  29   a  of the overlap portions  27  and  29  refer to side edge portions, of the overlap portions  27  and  29 , close to a center of the plate spring body  20  in the axial direction F. In this embodiment, the facing inner side edge portions  27   a  and  29   a  of the overlap portions  27  and  29  extending from the base portion  21  at a constant width are arranged parallel to each other, and a gap S having a constant width is formed between the inner side edge portions  27   a  and  29   a  along the circumferential direction F of the plate spring body  20 . Side edge portions opposite to the inner side edge portions  27   a  and  29   a  of the overlap portions  27  and  29  in the axial direction F are set as outer side edge portions  27   b  and  29   b.    
     Further, the pair of tab portions  40  and  50  provided at both end portions of the plate spring body  20  in the circumferential direction are bent and extend outward in the radial direction of the plate spring body  20 , from tip ends of the first arm portion  23  and the second arm portion  25  in the extending direction. The pair of tab portions  40  and  50  is a portion to be gripped by a tool (not shown) such as pliers or pincers, a clamp diameter-expanding device, or the like. 
     As illustrated in  FIGS. 1, 5, 9 , and the like, the first tab portion  40  in this embodiment has a bent portion  41  and an operating portion  43 . The bent portion  41  is bent at a predetermined angle, and extends from the tip end of the first arm portion  23  in the extending direction so as to rise outward in the radial direction (outer diameter direction) of the plate spring body  20 . The operating portion  43  is bent from a tip end of the bent portion  41  so as to be folded back inward in the radial direction (inner diameter direction) of the plate spring body  20 . 
     As illustrated in  FIG. 6 , a tip end portion  43   a  of the operating portion  43  extends along the axial direction F of the plate spring body  20  toward a side of the second arm portion  25  provided with the second tab portion  50 . The operating portion  43  is provided with a length allowing the operation portion  43  to fit in a plate width of the plate spring body  20  (see  FIG. 6 ) in a free state where the diameter of the plate spring body  20  is reduced, and to protrude from one side edge portion of the plate spring body  20  in the axial direction F, as illustrated in  FIGS. 10 and 12 , in a state where the diameter of the plate spring body  20  is expanded. 
     As illustrated in  FIGS. 4 and 6 , a cutout portion  44  is provided at one side portion close to the second tab portion  50 , that is, an inner side portion in the axial direction F, of the bent portion  41 . Further, at an inner side portion of the first tab portion  40  in the axial direction F (one side portion close to the second tab portion  50 ), an inclined portion  45  is formed that gradually widens from the cutout portion  44  toward the tip end of the first arm portion  23  in the extending direction. 
     On the other hand, as illustrated in  FIGS. 1, 5, 9 , and the like, the second tab portion  50  in this embodiment has a bent portion  51  and an operating portion  53 . The bent portion  51  is bent at a predetermined angle, and extends from the tip end of the second arm portion  25  in the extending direction so as to rise outward in the radial direction of the plate spring body  20 . The operating portion  53  is bent from a tip end of the bent portion  51  so as to be folded back inward in the radial direction of the plate spring body  20 . 
     As illustrated in  FIGS. 4 and 6 , a cutout portion  54  is provided at one side portion close to the first tab portion  40 , that is, an inner side portion in the axial direction F, of the bent portion  51 . Further, at an inner side portion of the second tab portion  50  in the axial direction F (one side portion close to the first tab portion  40 ), an inclined portion  55  is formed that gradually widens from the cutout portion  54  toward the tip end of the second arm portion  25  in the extending direction. 
     The pair of tab portions is not limited to the above shapes. For example, as illustrated in  FIG. 14 , the tab portions may have a shape in which operating portions  43 A and  53 A of the respective tab portions  40  and  50  extend from the bent portions  41  and  51  without being bent so as to be folded back with respect to the bent portions  41  and  51 , as long as the tab portions can be gripped by a tool such as pliers or pincers. 
     When the pair of tab portions  40  and  50  are moved close to each other in the circumferential direction E of the plate spring body  20 , and are deflected and deformed by being moved close to each other in the axial direction F of the plate spring body  20 , from a free state where the pair of tab portions  40  and  50  are separated from each other in the circumferential direction E and the diameter of the plate spring body  20  is reduced as illustrated in  FIGS. 1, 5 , and  6 , a surface  47  (inner surface opposite to an outer surface close to an outer peripheral surface of the first arm portion  23 ) of the bent portion  41  of the first tab portion  40  and a surface  57  (inner surface opposite to an outer surface close to an outer peripheral surface of the second arm portion  25 ) of the bent portion  51  of the second tab portion  50  are disposed to face each other in a predetermined range, as illustrated in  FIGS. 3 and 7 to 9 . 
     As described above, in a state where the pair of tab portions  40  and  50  are brought close to each other in the circumferential direction E and in the axial direction F, engagement portions that hold the plate spring body  20  in a state where the diameter of the plate spring body  20  is expanded are respectively provided on the surfaces  47  and  57  of the pair of tab portions  40  and  50 , which face each other (hereinafter, simply referred to as “facing surface  47 ” and “facing surface  57 ”). 
     In this embodiment, as illustrated in  FIGS. 8A and 8B , the engagement portions of the pair of tab portions  40  and  50  have recesses  60  and  60 , respectively, and each peripheral edge portion of the recesses  60  and  60  constitutes a protrusion  62  that is to be engaged with and disengaged from the recess  60  of the mating side, thus making a structure of recess/protrusion fitting (see  FIG. 11 ). Referring also to  FIG. 2 , on the facing surface  47  of the first tab portion  40  and the facing surface  57  of the second tab portion  50 , the recesses  60  having a substantially rectangular concave shape are provided respectively, with a predetermined depth so as not to penetrate the respective tab portions  40  and  50 . Peripheral edge portions, of the recesses  60 , on the inner side edge portion  27   a  side constitute the protrusions  62  that extend in a protruding manner along the extending direction of the respective bent portions  41  and  51  of the tab portions  40  and  50 . Further, the protrusions  62  do not protrude from the respective facing surfaces  47  and  57  of the tab portions  40  and  50 . 
     As illustrated in  FIG. 6 , as viewing the plate spring body  20  from the radial direction R, the engagement portions (the recesses  60  and the protrusions  62 ) are provided on the tab portions  40  and  50 , at positions closer to the outer side edge portions  27   b  and  29   b  being opposite to the facing inner side edge portions  27   a  and  27   a  of the overlap portions  27  and  27  of the first arm portion  23  and the second arm portion  25  in the axial direction F than to the facing inner side edge portions  27   a  and  27   a.  Further, in a free state where the diameter of the plate spring body  20  is reduced, the engagement portions (the recesses  60  and the protrusions  62 ) provided on the tab portions  40  and  50  are formed to be displaced from each other in the axial direction F of the plate spring body  20  (see  FIG. 6 ). 
     Further, in order to hold the plate spring body  20  in a state where the diameter of the plate spring body  20  is expanded, as indicated by arrows E 1  and E 1  in  FIG. 6 , the pair of tab portions  40  and  50  are brought close to each other in the circumferential direction E of the plate spring body  20  to expand the diameter of the plate spring body  20  as illustrated in  FIG. 13 . From this state, as indicated by arrows F 1  and F 1  in  FIG. 13 , the tab portions  40  and  50  are side-shifted, deflected and deformed so as to be brought close to each other in the axial direction F of the plate spring body  20 , and the recesses  60  and the protrusions  62  of the tab portions  40  and  50  overlap with each other in the axial direction F. Then, the protrusion  62  of the second tab portion  50  enters the recess  60  of the first tab portion  40  through an opening  64 , and the protrusion  62  of the first tab portion  40  enters the recess  60  of the second tab portion  50  through an opening  64 . As a result, as illustrated in  FIG. 11 , the protrusions  62  are engaged with inner peripheral edges of the recesses  60  respectively and the protrusions  62  enter the recesses  60  respectively. Accordingly, the protrusions  62  are held so as not to come out of the recesses  60 , the recesses  60  and the protrusions  62  are recess/protrusion fitted, and the plate spring body  20  is held in a state where the diameter of the plate spring body  20  is expanded against an elastic restoring force. 
     In the clamp  10 , since the engagement portions for holding the plate spring body  20  in the state where the diameter of the plate spring body  20  is expanded are not provided on the plate spring body  20  but in the pair of tab portions  40  and  50  formed in a bent manner in the plate spring body  20 , in a state where the plate spring body  20  is held so that the diameter of the plate spring body  20  is expanded by engaging the engagement portions of the pair of tab portions  40  and  50 , the pair of arm portions  23  and  25  of the plate spring body  20  do not overlap with each other in the circumferential direction E as viewing the plate spring body  20  from the axial direction F, as illustrated in  FIG. 9 . 
     Since the engagement portions of the tab portions  40  and  50  are formed to be displaced from each other in the axial direction F of the plate spring body  20 , and are engaged in a state where the tab portions  40  and  50  are deflected and deformed by being brought close to each other in the axial direction F, elastic restoring forces applies in directions to separate the tab portions  40  and  50  from each other in the axial direction F, as indicated by arrows F 2  and F 2  in  FIG. 11 . Accordingly, the protrusions  62  engage with inner peripheral edges on the inner side edge portions  27   a  and  29   a  side of the overlap portions  27  and  29  of the recesses  60 . 
     In this embodiment, at the time of bringing the pair of tab portions  40  and  50  close to each other in the circumferential direction E to expand the diameter of the plate spring body  20  and bringing the pair of tab portions  40  and  50  close to each other in the axial direction F of the plate spring body  20  to engage the engagement portions with each other, since the cutout portions  44  and  54  are provided at the inner side portions of the tab portions  40  and  50  in the axial direction F respectively, the engagement portions engage with each other in a state where the cutout portions  44  and  54  enter each other as illustrated in  FIGS. 7 and 10 . 
     At the time of reducing the diameter of the plate spring body  20  from the state where the plate spring body  20  is held so that the diameter of the plate spring body  20  is expanded, the tab portions  40  and  50  are brought close to each other in the circumferential direction E by gripping the operating portions  43  and  53  of the tab portions  40  and  50  by a tool such as pliers or pincers. Then, the protrusion  62  of the second tab portion  50  side comes out of the recess  60  of the first tab portion  40  side through the opening  64  of the first tab portion  40  side, and the protrusion  62  of the first tab portion  40  side comes out of the recess  60  of the second tab portion  50  side through the opening  64  of the second tab portion  50  side, thereby releasing the engagement between the engagement portions. At this time, since the engagement portions provided on the tab portions  40  and  50  are formed to be displaced from each other in the axial direction F of the plate spring body  20 , and are engaged in a state where the tab portions  40  and  50  are deflected and deformed by being brought close to each other in the axial direction F, the engagement portions take to positions not overlapping with each other in the axial direction F due to the elastic restoring forces of the tab portions  40  and  50  when the engagement between the engagement portions is released. In this state, a tool such as pliers or pincers is opened to separate the tab portions  40  and  50  from each other in the circumferential direction E, so that the diameter of the plate spring body  20  can be reduced. 
     In this embodiment, since the inclined portions  45  and  55  are formed in the first tab portion  40  and the second tab portion  50  respectively, at the time of bringing the tab portions  40  and  50  close to each other in the circumferential direction E by gripping the operating portions  43  and  53  of the tab portions  40  and  50  using a tool such as pliers or pincers in order to reduce the diameter of the plate spring body  20  from an expanded diameter holding state as described above, the bent portion  51  of the second tab portion  50  abuts on the inclined portion  45  of the first tab portion  40  to guide the second tab portion  50  in a direction (see arrow F 2  in  FIG. 10 ) opposite to a deflection direction thereof, and the bent portion  41  of the first tab portion  40  abuts on the inclined portion  55  of the second tab portion  50  to guide the first tab portion  40  in a direction (see arrow F 2  in  FIG. 10 ) opposite to a deflection direction thereof. By adopting such a configuration, it is possible to improve workability in reducing the diameter of the plate spring body  20  from the expanded diameter holding state. In particular, occurrence that the protrusion  62  enters the recess  60  again after being extracted from the recess  60  can be prevented, thereby enhancing diameter reduction workability of the clamp  10 . 
     Although as the engagement portion in this embodiment, a structure is set in which the recess  60 , the protrusion  62 , and the like are provided, for example, the engagement portion may be a structure having a through hole penetrating, the tab portion instead of having the recess, or a structure in which only one tab portion is provided with the recess or through hole and the other tab portion is provided with the protrusion (such structures will be described in an embodiment to be described later). The structure of the engagement portion is not particularly limited as long as the structure allows the engagement portions provided on tab portions to engage with each other and allows to hold the state where the diameter of the plate spring body is expanded. 
     Next, a procedure of fastening and fixing a flexible hose  5  made of a material such as rubber to the piping  1  such as a pipe by using the clamp  10  having the above configuration will be described. 
     First, from a state where the pair of tab portions  40  and  50  are separated from each other in the circumferential direction E and the diameter of the plate spring body  20  is reduced as illustrated in  FIGS. 1 and 2 , the tab portions  40  and  50  are gripped by a tool such as pliers or pincers to be brought close to each other in the circumferential direction E to expand the diameter of the plate spring body  20  (see  FIG. 13 ), and from this state, further the tab portions  40  and  50  are deflected and deformed by being brought close to each other in the axial direction F (see arrow F 1  in  FIG. 13 ), so that the recesses  60  and the protrusions  62  of the tab portions  40  and  50  overlap with each other in the axial direction F. Then, the cutout portions  44  and  54  of the tab portions  40  and  50  enter each other, the protrusions  62  and  62  of the tab portions  40  and  50  of the mating side enter the recesses  60  of the tab portions  40  and  50  respectively through the openings  64  and  64 , and the protrusions  62  engage with the inner peripheral edges of the recesses  60  respectively (see  FIG. 11 ). As a result, as illustrated in  FIGS. 3 and 7 , the plate spring body  20  can be held in a state where the diameter of the plate spring body  20  is expanded. 
     Next, after the clamp  10  in a state where the diameter of the clamp  10  is expanded is disposed on an outer periphery of the hose  5  attached to an outer periphery of one end portion of the piping  1 , the operating portions  43  and  53  of the tab portions  40  and  50  are gripped by an appropriate tool to bring the tab portions  40  and  50  close to each other in the circumferential direction E. Then, since the protrusions  62  of the tab portions  40  and  50  of the mating side pass from the openings  64  of the tab portions  40  and  50 , and the protrusions  62  and  62  of the tab portions  40  and  50  of the mating side come out of the recesses  60  and  60  of the tab portions  40  and  50 , the engagement between the engagement portions is released. At the same time, the bent portions  41  and  51  of the tab portions  40  and  50  of the mating side abut on the inclined portions  45  and  55  of the tab portions  40  and  50 , the tab portions  40  and  50  are respectively guided in directions opposite to the deflection directions thereof (see arrows F 2  and F 2  in  FIG. 10 ), and the engagement portions of the tab portions  40  and  50  take to positions not overlapping with each other in the axial direction F. In this state, the diameter of the plate spring body  20  is reduced by separating the tab portions  40  and  50  in the circumferential direction F, and thus the hose  5  can be fastened and fixed to the piping  1  as illustrated in  FIGS. 1 and 2 . 
     Further, in the clamp  10 , since the engagement portions (recesses  60  and protrusions  62  in this case) that hold the plate spring body  20  in the state where the diameter of the plate spring body  20  is expanded are provided on the pair of the tab portions  40  and  50 , a structure can be implemented in which the engagement portions do not exist in the arm portions  23  and  25  of the plate spring body  20 . Meanwhile, since the engagement portions are provided on the tab portions  40  and  50 , at positions closer to the outer side edge portions  27   b  and  29   b  being opposite to the facing inner side edge portions  27   a  and  27   a  of the overlap portions  27  and  27  in the axial direction F than to the facing inner side edge portions  27   a  and  27   a,  a structure can be implemented in which the engagement portions do not protrude in the axial direction F of the plate spring body  20  from the inner side edge portions  27   a  and  29   a  of the overlap portions  27  and  29 . Therefore, as illustrated in  FIG. 6 , when the diameter of the plate spring body  20  is reduced, the overlap portions  27  and  29  are disposed in the arm portions  23  and  25  so as to be close to each other in the axial direction F of the plate spring body  20 , so that the gap S between the facing inner side edge portions  27   a  and  29   a  of the overlap portions  27  and  29  can be made as small as possible. As a result, it is possible to improve performance of sealing between the hose  5  fastened and fixed by the clamp  10  and the piping  1 . 
     In this embodiment, the engagement portion of one tab portion (both tab portions  40  and  50  in this case) has the recess  60 , and the other engagement portion provided on the other tab portion (tab portions  50  and  40  of the mating side) has the protrusion  62  that is to be engaged with and disengaged from the recess  60 . Therefore, the protrusion of other tab portion is engaged with the recess of the one tab portion, here, the protrusion  62  of the second tab portion  50  is engaged with the recess  60  of the first tab portion  40  or the protrusion  62  of the first tab portion  40  is engaged with the recess  60  of the second tab portion  50 , so that the plate spring body  20  can be held in the state where the diameter of the plate spring body  20  is expanded. At this time, since the protrusion  62  enters the recess  60 , the protrusion  62  can be made difficult to get out from the recess  60 , and the state where the diameter of the plate spring body  20  is expanded can be held more reliably. Further, since the recess  60  can be formed by press molding or hollow molding, forming of the engagement portion is easier as compared with a case where the engagement portion is formed by cutting and raising, or the like. Even when the engagement portion has a through hole instead of the recess, the same effect as the above-described effect can be obtained. 
     Further, in this embodiment, the opening  64  through which the cutout portions  44  and  54  communicate with the recess  60  is provided on at least one of the tab portions (both tab portions  40  and  50  in this case), and at the time of engaging the engagement portions with each other in order to expand the diameter of the plate spring body  20 , the protrusion  62  of the other tab portion (both tab portions  40  and  50  in this case) pass through the opening  64  and enter the recess  60 . Therefore, the protrusion  62  provided on the other tab portion side can be formed in a protruding manner not protruding from a surface in a thickness direction of the tab portion, and the protrusion  62  can be easily formed. When the protrusion  62  is to be inserted into the recess  60  in a case where the opening  64  is not provided, it is essential to configure the protrusion  62  to protrude from the surface in the thickness direction of the tab portion, which makes it difficult to form the protrusion  62 . Even when the engagement portion has a through hole instead of the recess, the same effect as the above-described effect can be obtained. 
     Further, in this embodiment, the cutout portions  44  and  54  are provided on the pair of tab portions  40  and  50  respectively. At the time of expanding the diameter of the plate spring body  20 , the cutout portions  44  and  54  enter each other and the engagement portions provided on the pair of tab portions  40  and  50  engage with each other. Therefore, as illustrated in  FIG. 13 , in a state where the diameter of the plate spring body  20  is expanded by bringing the pair of tab portions  40  and  50  close to each other in the circumferential direction E, a movement amount of the pair of tab portions  40  and  50  at the time of bringing the pair of tab portions  40  and  50  close to each other in the axial direction F as indicated by arrows F 1  and F 1  in  FIG. 13 , can be increased. As a result, since amounts of deflection and deformation of the pair of tab portions  40  and  50  or the arm portions  23  and  25  can be increased, it is possible to smoothly reduce the diameter of the plate spring body  20  at the time of reducing the diameter of the plate spring body  20  by releasing the engagement between the engagement portions. 
     Further, in this embodiment, the engagement portions of the pair of tab portions  40  and  50  have the recesses  60  and  60  respectively, and the peripheral edge portion of each recess  60  constitutes the protrusion  62 . Therefore, at the time of engaging the engagement portions of the pair of tab portions  40  and  50  by bringing the pair of tab portions  40  and  50  close to each other in the axial direction F, in a state where the diameter of the plate spring body  20  is expanded by bringing the pair of tab portions  40  and  50  close to each other in the circumferential direction E from a state where the diameter of the plate spring body  20  is reduced, the protrusion  62  of one engagement portion enters the recess  60  of the other engagement portion and the protrusion  62  of the other engagement portion enters the recess  60  of one engagement portion, so that the recesses  60  and the protrusions  62  of the engagement portions are recess/protrusion fitted with each other as illustrated in  FIG. 11 . Thus, a holding force for holding the plate spring body  20  in the state where the diameter of the plate spring body  20  is expanded can be further increased. 
       FIGS. 15, 16A and 16B  illustrate a second embodiment of a hose clamp according to the present invention. Substantially the same parts as those in the above-described embodiment are denoted by the same reference signs, and description thereof will be omitted. 
     A structure of the engagement portions provided on the pair of tab portions  40  and  50  of a hose clamp  10 A (hereinafter, referred to as “clamp  10 A”) of this embodiment is different from that of the above embodiment. 
     That is, as illustrated in  FIGS. 15 and 16A , the engagement portion of the first tab portion  40  side has a through hole  66  penetrating the first tab portion  40  over a thickness thereof, while the engagement portion of the second tab portion  50  side has the same recess  60  as in the above embodiment (see  FIG. 16B ). The through hole  66  of the first tab portion  40  and the cutout portion  44  are communicated with each other by the opening  64 . Further, a peripheral edge portion of the through hole  66  of the first tab portion  40  side constitutes a protrusion  62 A that is to be engaged with and disengaged from the recess  60  of the second tab portion  50  side. 
     In this embodiment, by engaging the protrusion  62 A of the first tab portion  40  with the recess  60  of the second tab portion  50 , the plate spring body  20  can be held in the state where the diameter of the plate spring body  20  is expanded (see  FIG. 15 ). On the other hand, by extracting the protrusion  62 A of the first tab portion  40  from the recess  60  of the second tab portion  50 , the diameter of the plate spring body  20  can be reduced. 
       FIGS. 17, 18A and 18B  illustrate a third embodiment of a hose clamp according to the present invention. Substantially the same parts as those in the above-described embodiment are denoted by the same reference signs, and description thereof will be omitted. 
     A structure of the engagement portions provided on the pair of tab portions  40  and  50  of a hose clamp  10 B (hereinafter, referred to as “clamp  10 B”) of this embodiment is different from those of the above embodiments. 
     That is, as illustrated in  FIGS. 17, 18A and 18B , the engagement portions of the tab portions  40  and  50  respectively have through holes  66  penetrating the tab portions  40  and  50 , and peripheral edge portions thereof constitute the protrusions  62  and  62 . Further, the protrusions  62  and  62  of the tab portions  40  and  50  pass through the openings  64  and  64  to enter the through holes  66  and  66  of the tab portions  50  and  40  of the mating side respectively, and the protrusions  62  and  62  engage with each other, so that the plate spring body  20  can be held in the state where the diameter of the plate spring body  20  is expanded (see  FIG. 17 ). On the other hand, by extracting the protrusions  62  and  62  of the tab portions  50  and  40  of the mating side from the through holes  66  and  66  of the tab portions  40  and  50 , respectively, it is possible to reduce the diameter of the plate spring body  20 . 
       FIGS. 19, 20A and 20B  illustrate a fourth embodiment of a hose clamp according to the present invention. Substantially the same parts as those in the above-described embodiment are denoted by the same reference signs, and description thereof will be omitted. 
     A structure of the engagement portions provided on the pair of tab portions  40  and  50  of a hose clamp  10 C (hereinafter, referred to as “clamp  10 C”) of this embodiment is different from those of the above embodiments. 
     That is, as illustrated in  FIGS. 19 and 20A , the engagement portion of the first tab portion  40  side has the through hole  66  penetrating the first tab portion  40  over a thickness thereof, while the engagement portion of the second tab portion  50  side has a recess  60 C. However, the recess  60 C has a shape not having the opening  64 , which allows the recess  60 C to communicate with the cutout portion  54  as the recess  60  in the first and second embodiments. A peripheral edge portion of the through hole  66  of the first tab portion  40 ) side constitutes a protrusion  62 C that is to be engaged with and disengaged from the recess  60 C of the second tab portion  50  side. The protrusion  62 C is shorter than the protrusion  62 A in the second embodiment. 
     In this embodiment, by engaging the protrusion  62 C of the first tab portion  40  with the recess  60 C of the second tab portion  50 , the plate spring body  20  can be held in the state where the diameter of the plate spring body  20  is expanded (see  FIG. 19 ). On the other hand, by extracting the protrusion  62 C of the first tab portion  40  from the recess  60 C of the second tab portion  50 , the diameter of the plate spring body  20  can be reduced. 
     The present invention is not limited to the embodiments described above. Various modified embodiments are possible within the gist of the present invention, and such embodiments are also included in the scope of the present invention. 
     REFERENCE SIGNS LIST 
       10 ,  10 A,  10 B, IOC hose clamp (clamp) 
       20  plate spring body 
       21  base portion 
       23  first arm portion 
       25  second arm portion 
       27  first overlap portion 
       27   a  inner side edge portion 
       27   b  outer side edge portion 
       29  second overlap portion 
       29   a  inner side edge portion 
       29   b  outer side edge portion 
       40  first tab portion 
       44  cutout portion 
       47  facing surface 
       50  second tab portion 
       54  cutout portion 
       57  facing surface 
       60 ,  60 C recess 
       62 ,  62 A,  62 C protrusion 
       64  opening 
       66  through hole