Abstract:
The present invention discloses a hoop as well as a manufacturing method and a use method of the hoop. The hoop comprises a clamping belt, wherein the clamping belt is bent to form a hoop body with a sleeving area; the hoop body forms a superposed part; the superposed part comprises an outer belt body and an inner belt body: and the sleeving area is elliptical. The manufacturing method thereof comprises the steps of producing a clamping belt at first, and then directly bending the clamping belt to form a hoop body with an elliptical sleeving area. The use method thereof comprises the steps of directly bending a clamping belt to form a hoop body with a sleeving area, carrying out pre-forming treatment on the sleeving area to enable the sleeving area to be elliptical, sleeving the hoop body on a pipe fitting to enable the hoop body to form abutting connection with the pipe fitting at a short shaft part corresponding to the sleeving area, and further shrinking and clamping the hoop through a hoop clamping tool. The present invention aims at providing a hoop. The hoop has the advantages of being convenient in installation and capable of being effectively pre-fixed to the pipe fitting.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority benefit of a Chinese patent application No. 201510990443.4, filed on Dec. 24, 2015. The content of the aforementioned application, including any intervening amendments thereto, is incorporated herein by reference. 
       TECHNICAL FIELD 
       [0002]    The present invention relates to a clamping element, and more specifically relates to a hoop. 
       BACKGROUND 
       [0003]    A fastener on a pipe fitting, e.g., a hoop, also called as a lug clip and provided with a circular inner ring, is widely applied to life. At present, a Chinese patent with an application number of CN201380025000.0 discloses a lug clip; and the lug clip is provided with a clamping belt in which a lug-shaped fastening part is formed, and two legs extending outwards and mutually connected through a rib plate. 
         [0004]    Because the inner diameter of the lug clip is greater than the outer diameter of a pipe fitting, the lug clip is quite liable to loose in case of being sleeved on the pipe fitting, however, if the inner diameter of the lug clip is directly reduced to be equal to the outer diameter of the pipe fitting, surface-surface friction will be formed between the pipe fitting and the lug clip, and operating personnel will inconveniently sleeve the lug clip on the pipe fitting. In addition, during installation, the lug clip is moved to an expected position on the pipe fitting, the lug clip needs to be located by one hand, and the fastening part needs to be further deformed by the other hand with a lug clip clamping tool to fasten the lug clip until an expected clamping pressure is achieved. 
         [0005]    With regard to the lug clip, a hoop body with a normal-specification hoop inner diameter needs to be produced in advance, and the fastening part is pre-deformed in a production state to reduce the inner diameter of the lug clip and enable the inner diameter of the lug clip to be more approximate to the outer diameter of the pipe fitting but not equal to the outer diameter of the pipe fitting, so as to realize that an anti-loosing effect is achieved when the lug clip is pre-fixed to the pipe fitting, so that the lug clip is assembled on the pipe fitting with basically no clearance, and then secondary clamping needs to be carried out on the fastening part when the hoop body arriving at the expected position is finally fixed, so that secondary shrinking is carried out on the whole hoop body, and the hoop body is completely locked with the pipe fitting while achieving a limit degree. Therefore, secondary clamping and shrinking treatment is carried out on the fastening part, and is time-wasting and labor-wasting, thus the overall production efficiency will be greatly reduced and production cost will be increased. Moreover, different operation table surfaces are needed for carrying out secondary clamping on the fastening part, thus the accuracy is greatly reduced. What&#39;s more, because the fastening part is sequentially subjected to secondary deformation, it is difficult to control an applying force, thus the risk of breakage of the lug clip is greatly increased, and then the instability of installation and fastening for the lug clip is caused. 
         [0006]    Another Chinese patent with an application number of CN201520555541.0 discloses an anti-loosing hoop for a pipe fitting. The anti-loosing hoop comprises a clamping belt  1 , wherein the clamping belt  1  is bent to be circular and provided with a superposed part  11 ; the superposed part  11  comprises an outer part and an inner part; and through clamping connection and pre-fixing between upper hook-shaped parts of the inner part and upper damping grooves of the outer part, and clamping for side legs, that is, clamping lugs, arranged on t he outer part, the anti-loosing hoop is deformed to be tightened up as a whole, thus the inner diameter and the outer diameter are reduced. 
         [0007]    At this moment, a relative action force between the hook-shaped parts and the clamping grooves is increased. Because it is difficult to control a clamping force on the clamping lugs, specifically, as shown in  FIG. 5 , a stroke from a second clamping connection element  42  to a second locking resisting side  521  is equal to a stroke from a first clamping connection element  41  to a first locking resisting side  511 ; and because the first locking side  511  is closer to a fastening part  122  relative to the second locking side  521  when the fastening part  122  is clamped, the first locking side  511  is stressed at first, and is more liable to break, thus the whole lug clip is liable to break, and then the whole hoop is broken to fail, and unnecessary waste is caused. 
       SUMMARY 
       [0008]    With regard to shortages existing in the prior art, the present invention aims at providing a hoop as well as a manufacturing method and a use method of the hoop. The hoop has the advantages of being convenient in installation and capable of being effectively pre-fixed to a pipe fitting. 
         [0009]    In order to realize the above purpose, the present invention provides the following technical solution: A hoop comprises a clamping belt, wherein the clamping belt is bent to form a hoop body with a sleeving area; the hoop body forms a superposed part; the superposed part comprises an outer belt body and an inner belt body; and the sleeving area is elliptical. 
         [0010]    Through the above technical solution, t he hoop body is sleeved on a pipe fitting, and the pipe fitting is inserted from the sleeving area; the elliptical sleeving area is capable of quite effectively performing an anti-loosing effect, and an elliptical short shaft forms line contact with the surface of the pipe fitting in advance to prevent the occurrence of the case of loosing when the hoop is pre-fixed to the pipe fitting; and meanwhile, operating personnel can also much easily sleeve the hoop on t he sleeved pipe fitting, and the operating personnel can, by virtue of the characteristic of the elliptical shape, much easily hold and operate with a knob by an arc surface formed by a long shaft and the short shaft, and it is easier for the hoop to arrive at and be fixed at an expected position through rotary propulsion. 
         [0011]    The hoop provided by the present invention is further configured as: clamping connection notches are arranged in any one of the outer belt body and the inner belt body, and clamping elements are correspondingly arranged on the other belt body. 
         [0012]    Through the above technical solution, the outer belt body and the inner belt body can be mutually locked. 
         [0013]    The hoop provided by the present invention is further configured as: each clamping connection notch comprises a first damping connection port and a second clamping connection port, each clamping connection element comprises a first clamping connection element and a second clamping connection element, the first clamping connection port comprises a first locking resisting side, and the second clamping connection port comprises a second locking resisting side; and when the clamping connection elements penetrate in the clamping connection notches to form locking, a stroke from the first clamping connection element to the first locking resisting side is greater than a stroke from t he second clamping connection element to the second locking resisting side. 
         [0014]    Through the above technical solution, when the hoop body is not clamped and fixed to the pipe fitting, a certain movement range is reserved respectively between the first clamping connection element and the first locking resisting side, and between the second clamping connection element and the second locking resisting side, for preventing cracking of the outer belt body due to instantaneous locking when the hoop body is clamped and shrunk; because the first locking resisting side is closer to the fastening part relative to the second locking resisting side, when the fastening part is shrunk and clamped, the first clamping connection element will contact with the first locking resisting side at first; therefore, due to the setting that the stroke from the first clamping connection element to the first locking resisting side is greater than the stroke from the second clamping connection element to t he second locking resisting side, the second locking resisting side is stressed by the first locking resisting side at first, and when the second locking resisting side is about to achieve a limit bearing force, the first clamping connection element is abutted against the first locking resisting side, the first locking resisting side starts to be stressed, and decomposes and bears a force stressed by the second locking resisting side; therefore, when the hoop body is locked, a time difference of the two locking resisting sides in stress time is caused due to the difference of the strokes between the two clamping elements and the corresponding locking resisting sides, and a buffering effect is performed on the cracking of the outer belt body due to a locking force; in this way, cracking of the first locking resisting side on the outer belt body due to instantaneous locking when the hoop body is clamped and shrunk;can be effectively prevented. At least two pairs of clamping connection notches and clamping elements are arranged, so that the strength and the stability of the hoop provided by the present invention can be greatly improved, and secondary protection is equivalently achieved. 
         [0015]    The hoop provided by the present invention is further configured as: the sleeving area comprises a long shaft and a short shaft, the outer belt body is provided with a fastening part vertically to the direction of the short shaft in the sleeving area, and the short shaft is superposed with the central line of the fastening part. 
         [0016]    Through the above technical solution because the short shaft is superposed with the central line of the fastening part, when the whole hoop body is locked through the fastening part, the outer belt body and the inner belt body are both capable of being uniformly stressed towards the short s haft, and shrunk and locked by taking the central line of the fastening part as a symmetrical line, and the occurrence of the case of breakage of the hoop body due to non-uniform local stresses is avoided. 
         [0017]    The hoop provided by the present invention is further configured as: the length range of the long shaft of the hoop body is 17.2 mm +/−0.25 mm, and the length range of the short shaft of the hoop body is 15.7 mm +/−0.25 mm. 
         [0018]    Through the above technical solution, generally speaking, the diameter of the pipe fitting is usually 15.8 mm, and therefore, the range is an optimal implementation range. 
         [0019]    The hoop provided by the present invention is further configured as: the difference range of the stroke from the first damping connection element to the first locking resisting side, and the stroke from the second clamping connection element to the second locking resisting side is 0.3 mm-0.6 mm. 
         [0020]    Through the above technical solution, practice has proven that, breakage of a part between the fastening part and each damping connection notch can be effectively prevented, and therefore, the range is the optimal gap difference range. 
         [0021]    A manufacturing method of a hoop comprises the steps of producing a clamping belt at first, and then directly bending the clamping belt to form a hoop body with an elliptical sleeving area. The hoop provided by the present invention is further configured as: the fastening part is clamped and shrunk in advance, so that the short shaft in the sleeving area, and the pipe fitting have an equal outer diameter. 
         [0022]    A use method of a hoop comprises the above hoop, and also comprises the following specific steps: directly bending a clamping belt to form a hoop body with a sleeving area; carrying out pre-forming treatment on the sleeving area to enable the sleeving area to be elliptical and enable the short shaft in the sleeving area and the pipe fitting to have an equal outer diameter; sleeving the hoop body on the pipe fitting to enable the hoop body to form abutting connection with the pipe fitting at a short shaft corresponding to the sleeving area; and further shrinking and clamping the hoop through a hoop clamping tool. 
         [0023]    With the ad option of the above technical solution, operating personnel enable the sleeving area to be in contact fit with the pipe fitting through mutual matching of the two methods of pre-clamping the fastening part or enabling the sleeving area to become elliptical, thus w hen the hoop body is sleeved on the pipe fitting, the hoop body is not liable to loose in case of being not finally fastened, and an anti-loosing effect can be quite effectively performed. Because an arc surface pointed by the elliptical short shaft is abutted against the surface of the pipe fitting in advance, the occurrence of the case of loosing when the hoop is pre-fixed to the pipe fitting is prevented. Meanwhile, the operating personnel can also much easily sleeve the hoop on the sleeved pipe fitting, the operating personnel can, by virtue of the characteristic of the elliptical shape, much easily hold and operate with a knob by an arc surface formed by a long shaft and the short shaft, and it is easier for the hoop to arrive at and be fixed at an expected position through rotary propulsion. 
         [0024]    By bending the clamping belt to directly form an elliptical shape, steps can be simplified, production flow can be accelerated, and the anti-loosing effect can be quite effectively performed. 
         [0025]    In conclusion, the present invention has the following beneficial effects:
   1. A certain movement range is reserved respectively between the first damping connection element and the first locking resisting side, and between the second clamping connection element and the second locking resisting side, for preventing cracking of the outer belt body due to instantaneous locking when the hoop body is clamped and shrunk; due to the setting that the stroke from the first clamping connection element to the first locking resisting side is greater than the stroke from the second clamping connection element to the second locking resisting side, the second locking resisting side is stressed by the first locking resisting side at first, and when the second locking resisting side is about to achieve a limit bearing force, the first clamping connection element is abutted against the first locking resisting side, the first locking resisting side starts to be stressed, and decomposes and bears a force stressed is locked, a time difference of the two locking resisting sides in stress time is caused due to the difference of the strokes between the two clamping elements and the corresponding locking resisting sides, and a buffering effect is performed on t he cracking of the outer belt body due to a locking force; in this way, cracking of the first locking resisting side on t he outer belt body due to instantaneous locking when the hoop body is clamped and shrunk can be effectively prevented.   2. In the case that the stroke from the second clamping connection element to the second locking resisting side is equal to the stroke from the first clamping connection element to the first locking resisting side, the movement tendency of the first clamping connection port in the hoop body with an elliptical sleeving area is more gentle compared with the movement tendency of the first clamping connection port in the hoop body with a circular sleeving area, and therefore, the hoop body is more not liable to crack while being shrunk.   3. By directly bending the clamping belt to pre-form an elliptical shape, a pre-deforming treatment operation on the fastening part can be effectively replaced, an anti-loosing effect during pre-fixing on the pipe fitting can also be achieved, and the fastening part can be prevented from many times of deformation, thus the stability and the firmness of the hoop body during clamping fastening are effectively improved and the occurrence of a usual case of breakage during clamping is avoided. In addition, the operation step of pre-clamping deforming treatment on the fastening part is also omitted. In this way, production and processing flow is optimized, production efficiency is greatly increased, and production cost is also reduced. The operating personnel can, by virtue of the characteristic of the elliptical shape, much easily hold and operate with a knob by an arc surface formed by a long shaft and the short shaft, and it is easier for the hoop to arrive at and be fixed at an expected position through rotary propulsion.   
 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0029]      FIG. 1  is a structural schematic diagram of an embodiment of a hoop of the present invention; 
           [0030]      FIG. 2  is a side view of an embodiment of a hoop of the present invention; 
           [0031]      FIG. 3  is an enlarged view of part A; 
           [0032]      FIG. 4  is a front view of a hoop of the present invention; 
           [0033]      FIG. 5  is a traditional hoop; 
           [0034]      FIG. 6  is a schematic diagram of a hoop body with a circular sleeving area; and 
           [0035]      FIG. 7  is a schematic diagram of a hoop body with a circular sleeving area. 
       
    
    
       [0036]    Description of the drawings:  1 . clamping belt;  10 . hoop body;  101 . sleeving area;  11 . superposed part;  12 . outer belt body;  122 . fastening part;  13 . inner belt body;  2 . long shaft;  3 , short shaft;  4 . clamping element;  41 . first clamping connection element;  42 . second clamping connection element;  5 . clamping connection notch;  51 . first clamping connection port;  511 . first locking resisting side;  52 , second clamping connection port; and  521 , second locking resisting side. 
       DETAILED DESCRIPTION 
       [0037]    The present invention is further described in details below in conjunction with the accompanying drawings through specific embodiments, and the embodiments below are merely descriptive and do not define the protection scope of the present invention. 
         [0038]    As shown in  FIG. 1  to  FIG. 4 , a specific embodiment of a hoop product is as follows: 
         [0039]    As shown in  FIG. 1  and  FIG. 4 , a hoop comprises a clamping belt  1 , wherein the clamping belt  1  is bent to form a hoop body  10  with a sleeving area  101 . The hoop body  10  is sleeved on a pipe fitting, and the sleeving area  101  is used for inserting the pipe fitting. The hoop body  10  forms a superposed part  11 , and the superposed part  11  comprises an outer belt body  12  and an inner belt body  13 . The sleeving area  101  comprises a long shaft  2  and a short shaft  3 , and the outer belt body  12  is provided with a fastening part  122 . 
         [0040]    As shown in  FIG. 2  and  FIG. 3 , clamping connection notches  5  are arranged in the outer belt body  12  (it should be noted herein that, the clamping connection notches  5  can be configured as through holes or blind holes which can be simply, conveniently and rapidly formed in one process); the inner belt body  13  is provided with clamping elements  4  (it should be noted herein that, the clamping connection notches  5  may also be arranged in the inner belt body  13 , and the clamping elements  4  are arranged on the outer belt body  12 , however, it should be noted that when the clamping elements  4  are arranged on the outer belt body  12 , the clamping connection notches  5  in the inner belt body  13  should be configured as the blind holes; in this way, the clamping elements  4  on the outer belt body  12  are prevented from penetrating through the clamping connection notches  5  in the inner belt body  13  to be directly abutted against the pipe fitting); each clamping connection notch  5  comprises a second clamping connection port  52  and a first clamping connection port  51 ; each clamping connection element  4  comprises a second clamping connection element  42  and a first clamping connection element  41 ; and the first damping connection element  41 , the second clamping connection element  42 , the fastening part  122 , the first clamping connection port  51  and the second clamping connection port  52  are sequentially arranged on the clamping belt  1 . 
         [0041]    The second clamping connection element  42  and the first clamping connection element  41  correspond to the second damping connection port  52  and the first clamping connection port  51  respectively, the second clamping connection port  52  comprises a second locking resisting side  521 , and the first clamping connection port  51  comprises a first locking resisting side  511 . When the hoop body  10  and the pipe fitting need to be clamped the first clamping connection element  41  forms locking resisting connection with the first locking resisting side  511 , and, the second clamping connection element  42  forms locking resisting connection with the second locking resisting side  521 . 
         [0042]    As shown in  FIG. 1  and  FIG. 4 , the sleeving area  101  is elliptical. The length range of the long shaft  2  of the hoop body  10  is 17.2 mm +/−0.25 mm, and the length range of the short shaft  3  of the hoop body  10  is 15.7 mm +/−0.25 mm. Generally speaking, the diameter of the pipe fitting is usually 15.8 mm, and therefore, the range is an optimal implementation range. 
         [0043]    The short shaft  3  of the hoop body  10  is superposed with the central line of the fastening part  122 . When the w hole hoop body  10  is locked through the fastening part  122 , the outer belt body  12  and the inner belt body  13  are both capable of being uniformly stressed towards the short shaft  3 , and shrunk and locked by taking the central line of the fastening part  122  as a symmetrical line, and the occurrence of the case of breakage of the hoop body  10  due to non-uniform local stresses is avoided. 
         [0044]    To prevent the occurrence of cracking of the hoop body, regardless of the shape of the sleeving area  101 , the hoop body can also be configured as follows: the stroke from the first clamping connection element  41  to the first locking resisting side  511  is greater than the stroke from the second clamping connection element  42  to the second locking resisting side  521 , and the difference range of two strokes is preferably 0.3 mm-0.6 mm. 
         [0045]    When t he hoop body  10  is not clamped and fixed to the pipe fitting, a certain movement range is reserved respectively between the first clamping connection element and the first locking resisting side, and between the second clamping connection element and the second locking resisting side, for preventing cracking of the outer belt body due to instantaneous locking when the hoop body is clamped and shrunk; because the first locking resisting side is closer to the fastening part relative to the second locking resisting side, when the fastening part is shrunk and damped, the first clamping connection element will contact with the first locking resisting side at first; therefore, due to t he setting that the stroke from the first damping connection element to the first locking resisting side is greater than the stroke from the second clamping connection element to the second locking resisting side, the second locking resisting side is stressed by the first locking resisting side at first, and when the second locking resisting side is about to achieve a limit bearing force, the first clamping connection element is abutted against the first locking resisting side, the first locking resisting side starts to be stressed, and decomposes and bears a force stressed by the second locking resisting side; therefore, when the hoop body is locked, a time difference of the two locking resisting sides in stress time is caused due to the difference of the strokes between the two clamping elements and the corresponding locking resisting sides, and a buffering effect is performed on the cracking of the outer belt body due to a locking force; in this way, cracking of the first locking resisting side on the outer belt body due to instantaneous locking when the hoop body is clamped and shrunk can be effectively prevented. 
         [0046]    However, it should be noted herein that, after many times of tests, the applicant finds that with regard to the hoop with the elliptical sleeving area  101 , it would be best to set the stroke from the first clamping connection element  41  to the first locking resisting side  511  to be greater than the stroke from the second clamping connection element  42  to the second locking resisting side  521 . 
         [0047]    The positions of the two clamping elements and the two clamping grooves are arranged according to that t he clamping belt is pre-formed to be provided with the elliptical sleeving area, after the traditional circular sleeving area  101  is pre-formed into the elliptical hoop body  10 , the elliptical short shaft  3  points to the fastening part  122 , and the elliptical long shaft  2  points to the second clamping connection port  52 ; if the stroke from the second clamping connection element  42  to the second locking resisting side  521  is still kept to be equal to the stroke from the first clamping connection element  41  to the first locking resisting side  511 , because the hoop body  10  is extruded to generate deformation the stroke from the first clamping connection element  41  to t he first locking resisting side  511  will be reduced, and the stroke from the second clamping connection element  42  to the second locking resisting side  521  will also be reduced, so that the first clamping connection port  51  and the second clamping connection port  52  will both early enter a stress phase; in addition, because the second clamping connection port  52  is closer to the arc surface where the outer belt body  12  pointed by the long shaft  2  is located, compared with the first clamping connection port  51 , the deformation degree of the arc surface where the second clamping connection port  52  is located is greater than the deformation degree of the arc surface where the first clamping connection port  51  is located; and therefore, the case of breakage of the outer belt body  12  between the fastening part  122  and the first clamping connection port  51 , of the hoop body  10  with the elliptical sleeving area  101  is extremely easily caused. 
         [0048]    As s hewn in  FIG. 6  and  FIG. 7 ,  FIG. 6  shows the hoop body  10  with the circular sleeving area  101 ;  FIG. 7  shows the hoop body  10  with the elliptical sleeving area  101 ; and in the case that the stroke from the second clamping connection element  42  to the second locking resisting side  521  is equal to the stroke from the first clamping connection element  41  to the first locking resisting side  511 , the movement tendency of the first clamping connection port  51  in  FIG. 7  is more gentle compared with the movement tendency of the first clamping connection port  51  in  FIG. 6 , and therefore, the hoop body  10  is more not liable to crack while being shrunk. 
         [0049]    Therefore, after the hoop body  10  is configured to be provided with the elliptical sleeving area  101 , it would be best to set the stroke difference of the first clamping connection element  41  and the second clamping connection element  42 , that is, the stroke from the second clamping connection element  42  to the second locking resisting side  521  is less than the stroke from the first clamping connection element  41  to the first locking resisting side  511 . 
         [0050]    Actually, a position with a movement distance is reserved for the first clamping connection element  41  on the first clamping connection port  51 , wherein the movement distance is longer than that of a position reserved for the second clamping connection element  42  on the second clamping connection port  52 , and a good effect of delayed stress is performed, so that the second clamping connection port  52 , the second locking resisting side  521  and the second clamping connection element  42  are stressed at first, and the first clamping connection port  51 , the first locking resisting side  511  and the first clamping connection element  41  are stressed again when a certain extent is achieved; in this way, a stress time difference is reasonably utilized, and the weak points of the clamping connection notches  5  in the outer belt body  12  are made up, thereby effectively preventing the breakage of the hoop. 
         [0051]    With regard to a specific embodiment of a manufacturing method of a hoop: 
         [0052]    The hoop can be directly pre-formed into a hoop body  10  with an elliptical sleeving area  101  for selling during production and manufacture; the hoop can also be manufactured to be in the form of a clamping belt  1  for selling, and then treated and formed into a hoop body  10  with an elliptical sleeving area  101  during use. In order to facilitate use of a user, operation steps can be simplified; and in the embodiment, preferably, the hoop is directly pre-formed into a hoop body  10  with an elliptical sleeving area  101  for selling during production and manufacture. 
         [0053]    In addition, the fastening part  122  can be directly pre-clamped and shrunk during production, or be pre-clamped and shrunk before use, or be directly clamped and shrunk in one process during use. In order to facilitate installation of installation personnel and save time and labor during later shrinking working, in the embodiment, preferably, the fastening part  122  is directly pre-clamped and shrunk during production or pre-clamped and shrunk before use. 
         [0054]    With regard to a specific embodiment of a use method of a hoop: 
         [0055]    Firstly, a clamping belt is directly bent to form a hoop body  10  with a sleeving area  101 ; secondly, pre-forming treatment is carried out on the sleeving area  101  and the sleeving area  101  is enabled to be elliptical (the manner of pre-forming during production or the manner of pre-forming before use can be adopted, the sleeving area  101  is directly formed to be elliptical by adopting the former manner, thus steps can be simplified and production flow can be accelerated, so that more convenience is brought for a user; and the latter manner is higher in selectivity and more flexible in use); the hoop body  10  is sleeved on the pipe fitting to enable the hoop body  10  to form abutting connection with the pipe fitting at a short shaft  3  corresponding to the sleeving area  101 ; and the hoop is further shrunk and clamped through a hoop clamping tool (the, manner of shrinking and clamping the whole hoop body  10 , or the manner of shrinking and clamping the fastening part  122 , or the manner of combining the two manners can be adopted). 
         [0056]    In conclusion, by directly bending the clamping belt  1  to pre-form an elliptical shape, a pre-deforming treatment operation on the fastening part  122  can be effectively replaced, an anti-loosing effect during pre-fixing on the pipe fitting can also be achieved, and the fastening part  122  can be prevented from many times of deformation, thus the stability and the firmness of the hoop body  10  during clamping fastening are effectively improved and the occurrence of a usual case of breakage during clamping is avoided In addition, the operation step of pre-clamping deforming treatment on the fastening part  122  is also omitted. In this way, production and processing flow is optimized, production efficiency is greatly increased, and production cost is also reduced. Meanwhile, the operating personnel can also much easily sleeve the hoop body  10  on the pipe fitting, the operating personnel can, by virtue of the characteristic of the elliptical shape, much easily hold and operate with a knob by an arc surface formed by a long shaft  2  and the short shaft  3 , and it is easier for the hoop to arrive at and be fixed at an expected position through rotary propulsion. According to the present invention, on one hand, an inner circumference is increased in disguised form in a manner oft he elliptical shape; on the other hand, the stress time of bulged elements is slowed and delayed by designing a gap difference between the adjacent clamping elements  13 , so as to compensate the weak points.