Patent Publication Number: US-2021161077-A1

Title: Pruner Saw Clamping Device and Pruner Saw with the Device

Description:
TECHNICAL FIELD 
     The present utility model relates to a reciprocating saw clamping device and a reciprocating saw having the clamping device, and in particular relates to a clamping device for securing an object to be cut such as a branch, and a reciprocating saw having the clamping device. 
     BACKGROUND ART 
     An electric reciprocating saw is an electric tool that is commonly used for cutting objects; due to its ability to perform cutting operations conveniently and quickly, it is used very widely in places such as homes and gardens. Electric reciprocating saws are mainly used for cutting objects such as wood, branches and pipes, but these objects are mostly round or tubular in shape, and easily roll or slip during cutting, thus making cutting difficult. To solve this problem, a common solution in the prior art is to mount a clamping component on the electric reciprocating saw, the clamping component being used to fix the object to be cut; the clamping component is generally mounted close to a saw blade of the electric reciprocating saw. When the object is being sawed, the clamping component can be set up on the object to be cut, such that the object is positioned in a clamping mouth part of the clamping component. This is equivalent to fixing the object to be cut below the saw blade of the reciprocating saw by means of the clamping component, and can make sawing work safer and easier. 
     However, the clamping mouth part of the abovementioned clamping component in the prior art has a fixed size, and as a result, clampable objects need to be within a certain size range, objects that are slightly too small or slightly too large in size cannot be clamped effectively. Moreover, a clamping component with such a structure is generally formed of components such as a blade guard, a front claw support and a front claw; the overall structure is complex, and the profile is large, with the result that the reciprocating saw is rather clumsy during cutting operations, and difficult to operate. This places a considerable burden on the operator in terms of carrying and performing jobs. 
     Summary of the Utility Model 
     To solve the abovementioned problems, the present utility model provides a reciprocating saw clamping device, the clamping device being mounted on a machine body of the reciprocating saw, close to a cutting saw blade located at a front end of the machine body of the reciprocating saw, and being configured to clamp an object to be cut when the reciprocating saw is performing a cutting operation, wherein the clamping device comprises a clamp and a clamp support, the clamp and clamp support being rotatably hinge-connected, and the clamping device is removably mounted on the machine body of the reciprocating saw by means of positioning structures which fit each other and are arranged on the clamp support and a housing of the reciprocating saw. 
     Preferably, an elastic member is also mounted between the clamp and clamp support, and the clamp can be rotated back to an initial position relative to the clamp support by means of the elastic member; in a state of having returned to the initial position, the clamping device lies against a front end part of the machine body of the reciprocating saw. 
     Preferably, the positioning structures comprise a first guide structure formed on the clamp support, and a second guide structure fitting the first guide structure and arranged on the housing; the positioning structures further comprise a first snap-fit structure formed on the clamp support, and a second snap-fit structure that can engage with the first snap-fit structure and is arranged on the housing. 
     Preferably, the first guide structure is a guide rib formed on an inside wall of the clamp support, and the second guide structure is a guide groove provided on a front-end side wall of the housing; the first snap-fit structure is a support part formed on an inner wall of the clamp support, and the second snap-fit structure is a snap-fit part mounted on the housing. 
     Preferably, the first guide structure is a pair of guide rods on the clamp support, and the second guide structure is a guide post arranged in an internal space at a front end of the housing; the first snap-fit structure is an engagement slot provided at an end part of the guide rod, and the second snap-fit structure is a positioning pin assembly arranged in the internal space. 
     Preferably, the snap-fit part is rotatably mounted on an inner wall of the housing, an elastic member is also mounted therebetween, and the snap-fit part can be rotated back to an initial position relative to the housing by means of the elastic member; the snap-fit part is operated by means of a button part mounted on the housing; when the button part is pressed, the snap-fit part will release the support part, and when the button part is released, the snap-fit part will rotate under the action of the elastic member to a position where the support part can be hooked. 
     Preferably, the button part comprises two buttons in an insertion fit with each other, the buttons being located at two sides of the snap-fit part respectively, and the buttons are pressed towards each other to operate the snap-fit part; an elastic member is also provided between the buttons, and the buttons can be returned by means of the elastic member to a position where the snap-fit part encounters no interference. 
     Preferably, a hook part is provided on the snap-fit part, and the snap-fit part hooks the support part by means of the hook part; when the buttons are pressed towards each other, the buttons approach each other and press the snap-fit part so that the hook part releases the support part. 
     Preferably, the elastic member is a torsion spring. 
     Preferably, the clamp and the clamp support are hinge-connected by means of a connecting pin; the torsion spring is fitted round the connecting pin, and has one end engaged with the clamp in an upward direction, and another end in abutment with the clamp support; an elastic shaft retaining ring is also mounted at an end part of the connecting pin. 
     Preferably, an inclined face sloping towards a rear end of the clamp support is also formed on the clamp support, and correspondingly, a limiting part is formed at an upper end part of the clamp in such a way as to be bent away from the clamp support; limiting is performed by abutment of the limiting part and the inclined face with each other. 
     Preferably, the positioning pin assembly comprises a positioning pin moveably mounted in the internal space; a positioning part is provided on a pin body of the positioning pin, and the engagement slot can be fastened by means of the positioning part; an elastic member for returning the positioning pin to an initial position is also fitted round the pin body of the positioning pin. 
     Preferably, the guide post is arranged on a side wall of the internal space, and crosses the internal space. 
     Preferably, the guide post is cylindrical; the pair of guide rods are arranged opposite each other in a vertical direction, and a gap therebetween is slightly larger than the diameter of the guide post. 
     Preferably, the guide rod may be made of a metal material or a plastic material; when a plastic material is used, the thickness of the guide rod is at least 3 mm. 
     Preferably, the clamp has a clamping claw and a clamp jaw that is formed at a lower end part of the clamping claw in such a way as to be bent away from the housing; when the clamping device lies against the housing, the clamp jaw is close to a receiving region for the object to be cut that is located at the front end part. 
     Preferably, a sawtooth-like structure is provided on a face of the clamping claw at a side facing the housing. 
     The present utility model also provides a reciprocating saw, comprising a handle, a cutting saw blade remote from the handle, and a reciprocating saw machine body located between the handle and the cutting saw blade, and further comprising the clamping device as described above. 
     Preferably, the reciprocating saw has a fastening ring for fastening the cutting saw blade, with a protrusion structure being provided in an axial direction on the periphery of the fastening ring; a tooth-like protrusion is also provided on the protrusion structure at a side where a force is exerted. 
     Preferably, two said protrusion structures are provided, the two protrusion structures being arranged opposite each other in a circumferential direction at the periphery of the fastening ring. 
     Having adopted the solution described above, the present utility model has the following beneficial effects: 
     The reciprocating saw clamping device in the present utility model comprises a clamp and a clamp support that are structurally simple and compact; the clamp and clamp support are hinge-connected together, and can be removed from and mounted on the reciprocating saw machine body as a unit. This also makes it easier to choose whether to mount or remove the clamping device according to actual needs during use. The clamping device and reciprocating saw in the present utility model are fixed to each other by means of snap-fit structures arranged on the clamp support and the housing; such a fixing structure is not only structurally simple, but also stable and reliable, and the corresponding mounting and removal operations are very simple. 
     When the clamping device of the present utility model is clamping an object to be cut, it is only necessary to put the object to be cut into the receiving region of the clamping device and lightly pull the reciprocating saw away from the object to be cut. The object to be cut slides naturally between the clamping claw of the clamp and a machine frame, and is close to the cutting saw blade; there is no need to manually pull the clamping claw. During cutting, the object to be cut is also clamped reliably at all times under the biasing action of the torsion spring on the clamping device, making operations safer and more reliable. The clamp in the present utility model can automatically adjust a clamping angle according to the size of the object to be cut, and at the same time has an angle limiting structure, so can satisfy cutting requirements of different sizes, with a larger range of operations. Furthermore, since the clamping device in the present utility model has a small structure overall, the machining process is simple and costs are low. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic drawing of the internal structure of the reciprocating saw to which the present utility model relates. 
         FIG. 2  is a schematic drawing of the clamping device to which embodiment 1 of the present utility model relates, in a state of having been removed from the reciprocating saw. 
         FIG. 3  is an exploded drawing of the clamping device to which embodiment 1 of the present utility model relates. 
         FIG. 4  is a schematic drawing of the internal structure of the clamp support in  FIG. 3 . 
         FIG. 5  is a schematic drawing of the structure of the snap-fit assembly in  FIG. 3 . 
         FIG. 6  is an exploded drawing of part of the snap-fit assembly in  FIG. 5 . 
         FIG. 7  is a schematic drawing of the clamping device to which embodiment 1 of the present utility model relates, clamping an object to be cut. 
         FIG. 8  is a schematic drawing of the clamping device to which embodiment 2 of the present utility model relates, in a state of having been removed from the reciprocating saw. 
         FIG. 9  is a structural drawing of the clamping device to which embodiment 2 of the present utility model relates. 
         FIG. 10  is a schematic drawing of the mounting structure of the clamping device to which embodiment 2 of the present utility model relates. 
     
    
    
     REFERENCE LABELS 
       
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 1, 1′-clamping device; 
                 11, 11′-clamp; 
               
               
                   
                 11a-clamping claw; 
                 11b-clamp jaw; 
               
               
                   
                 111, 111′-connecting plate; 
                 112-pin hole; 
               
               
                   
                 113, 113′-limiting part; 
                 12, 12′-clamp support; 
               
               
                   
                 121, 121′-connecting part; 
                 122-pin hole; 
               
               
                   
                 123-inclined face; 
                 124-guide rib; 
               
               
                   
                 125-support part; 
                 126-slot part; 
               
               
                   
                 127-guide rod; 
                 127a-engagement slot; 
               
               
                   
                 13, 13′-connecting pin; 
                 131-annular groove; 
               
               
                   
                 14-torsion spring; 
                 15-elastic shaft retaining ring; 
               
               
                   
                 16-snap-fit assembly; 
                 161-button part; 
               
               
                   
                 161a, 161b-button; 
                 161c-compression spring; 
               
               
                   
                 161a-1, 161b-1-guide part; 
                 161a-2-guide rib; 
               
               
                   
                 161b-2-engagement slot; 
                 161a-3, 161b-3-pressing part; 
               
               
                   
                 162-snap-fit part; 
                 162a-hook part; 
               
               
                   
                 162b-connecting pin; 
                 162c-gap; 
               
               
                   
                 162d-oblique face; 
                 162e-torsion spring; 
               
               
                   
                 2, 2′-housing; 
                 21, 21′-front end part; 
               
               
                   
                 21a′-recess; 
                 22-receiving part; 
               
               
                   
                 23-receiving region; 
                 24-guide groove; 
               
               
                   
                 25-internal space; 
                 251-insertion port; 
               
               
                   
                 26-guide post; 
                 27-positioning pin; 
               
               
                   
                 271-positioning part; 
                 272-compression spring; 
               
               
                   
                 3-motor; 
                 4-speed reducing gear assembly; 
               
               
                   
                 5-cylindrical cam assembly; 
                 6-cutting saw blade; 
               
               
                   
                 61-fastening ring; 
                 611-protrusion structure; 
               
               
                   
                 7-battery assembly; 
                 8-handle; 
               
               
                   
                 9-object to be cut. 
               
               
                   
                   
               
            
           
         
       
     
     DETAILED DESCRIPTION OF THE UTILITY MODEL 
     The present utility model is expounded below in accordance with the embodiments shown in the drawings. The embodiments disclosed on this occasion may be regarded as being non-limiting examples in all respects. The scope of the present utility model is not limited by the explanation of the embodiments below, being indicated by the scope of the claims alone, and comprises all variants that fall within the scope of the claims and have the same meaning as the scope of the claims. 
     It must be explained that in the description of device and component structures, orientations or positional relationships indicated by terms used such as “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner” and “outer”, etc. are based on the orientations or positional relationships shown in the drawings, and are merely intended to facilitate and simplify description; they do not indicate or imply that the device or component referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore must not be interpreted as limiting the present utility model. 
     Disclosed in the present utility model are a reciprocating saw clamping device, and a reciprocating saw having the clamping device. The clamping device  1  is removably mounted on a reciprocating saw machine body, close to a cutting saw blade, and used for clamping an object to be cut in a cutting operation, so that the cutting operation proceeds safely and reliably. The object to be cut is for example wood, plastic, metal, concrete or a mixture thereof; or made of a material selected from wood, plastic, metal and mixtures thereof. 
       FIG. 1  is a structural schematic drawing of the reciprocating saw in the present utility model; a housing  2  has been removed at one side in  FIG. 1 , to better display the internal structure of the reciprocating saw. As shown in  FIG. 1 , the interior of the reciprocating saw comprises a motor  3 ; an output shaft of the motor  3  is connected to a speed reducing gear assembly  4 ; an output end of the gear assembly  4  is connected to a cylindrical cam assembly  5 ; a mounting shaft of a cutting saw blade  6  is driven to reciprocate by means of the cylindrical cam assembly  5 , thus driving the cutting saw blade  6  to perform a reciprocating cutting operation, wherein the cutting saw blade is fixed to the mounting shaft and located at a front end of the machine body. The reciprocating saw further comprises a battery assembly  7  (only a mounting region is shown in  FIG. 1 ); the battery assembly  7  is removably mounted on the reciprocating saw machine body, close to a handle  8 , and is located at an extremity of the machine body; the battery assembly  7  is electrically connected to the motor  3 , and thereby supplies power to the motor  3 . 
     Embodiment 1 
     The clamping device  1  in this embodiment is removably connected to the machine body of the reciprocating saw;  FIG. 1  shows a schematic drawing of the clamping device  1  when mounted on the reciprocating saw machine body, and  FIG. 2  shows a schematic drawing of the clamping device  1  removed from the reciprocating saw machine body. The clamping device  1  can be selectively mounted on the reciprocating saw machine body or removed from the reciprocating saw machine body according to the circumstances of actual use. As shown in  FIG. 2 , the clamping device  1  is mounted at a front side of the reciprocating saw, close to the cutting saw blade  6 , and has a clamp  11  and a clamp support  12  hinge-connected to the clamp, wherein the clamp  11  has multiple clamping claws, preferably two clamping claws. Each clamping claw generally has a concave face or a partially concave face at a side facing the housing  2 , and correspondingly, a front end part  21  of the machine body (the housing  2 ) opposite the clamping device  1  has a forward-protruding structure matching the concave face, such that an object to be cut  9  is clamped through the cooperation of the clamp  11  and the front end part  21  (see  FIG. 7 ). A sawtooth-like structure is also provided on the concave face side of the clamping claw  11   a  of the clamp  11 ; the sawtooth-like structure is provided over the entire concave face of the clamping claw  11   a . Sawteeth may also be provided on only a part of a partial concave face as required; for example, the sawtooth-like structure is provided only in a middle part. Furthermore, a sawtooth-like structure may also be provided on the housing front end part  21  opposite the clamping claw  11   a , preferably on a part of the front end part  21  that is opposite a gap between the two clamping claws  11   a . In this embodiment, the sawtooth-like structure reduces the possibility that the object to be cut  9  will slip and/or rotate during placement and cutting, and it is thereby possible to better seize and hold the object to be cut  9 . Of course, in cases where it is necessary to prevent indentations from being produced in an outer surface of the object to be cut, the choice can also be made as required to replace the abovementioned sawtooth-like structure with a coarse-grained structure or another structure capable of producing high frictional resistance. 
     As shown in  FIG. 2 , a clamp jaw  11   b  is formed at an end part of the clamping claw  11   a ; the clamp jaw  11   b  is formed by bending away from the front end part  21  that end part of the clamping claw  11   a  which is remote from the side where the clamp support  12  is hinge-connected. When the object to be cut  9  is clamped, the clamp jaw  11   b  can abut the object to be cut  9  and push it towards a region between the clamping claw  11   a  and the front end part  21 . A receiving part  22  is also formed at a lower end of the front end part  21 ; the receiving part  22  is formed by the lower end of the front end part  21  of the housing  2  being bent towards the clamping device  1 . A receiving region  23  is formed between the receiving part  22  and the front end part  21 ; when the clamp  11  is in a closed position shown in  FIG. 1 , the clamp jaw  11   b  is close to the receiving part  22  and the receiving region  23 . In addition, the receiving region  23  has an obtuse-angle shape, and can receive the object to be cut  9  that is about to be cut by the cutting saw blade  6 ; such an obtuse-angle shape enables the object to be cut  9  to be placed more easily into the receiving region  23 , and when the object to be cut  9  slides along the receiving region  23  towards the clamp jaw  11   b , it will abut and grasp the object to be cut  9 . The clamp jaw  11   b  will then open to assist in guiding the object to be cut  9  into a position closer to the cutting saw blade  6 . 
     In this embodiment, as shown in  FIG. 3 , an upper end part of the clamp  11  is connected to a front end part of the clamp support  12 . Specifically, two sides of the upper end part of the clamp  11  are folded down to form two left and right connecting plates  111  connected to the clamp support  12 , the two connecting plates  111  each being provided with a pin hole  112 ; correspondingly, the front end part of the clamp support  12  is folded up to form a connecting part  121  corresponding to the connecting plates  111 . The connecting part  121  has two plate-like connecting members, which are capable of being fitted over outer sides of the connecting plates  111 . The connecting part  121  is provided with pin holes  122  corresponding to the pin holes  112  in the connecting plates  111 . The clamp  11  and clamp support  12  are connected by means of a connecting pin  13  passing through the pin holes  112 ,  122 . A torsion spring  14  is also fitted round the connecting pin  13 ; one end of the torsion spring  14  is engaged with the upper end part of the clamp  11  in an upward direction, while another end abuts an outside face of the clamp support  12 . Furthermore, an annular groove  131  for an elastic shaft retaining ring  15  to snap into is provided at an end part of the connecting pin  13 . The clamp  11 , clamp support  12  and torsion spring  14  are connected together by means of the connecting pin  13  and elastic shaft retaining ring  15 . The clamp  11  can rotate and return to its initial position under the action of the torsion spring  14 . When in the state of having returned to its initial position, the clamping device is in a closed position, with the clamp  11  thereof lying against the front end part  21  of the reciprocating saw. The torsion spring  14  may also be another elastic member, such as a flat spring, etc.; there is no restriction to the torsion spring form, and the same is true for the torsion spring and compression spring, etc. used hereinbelow. 
     In this embodiment, the clamping device  1  is fixed to the reciprocating saw machine body by means of a snap-fit structure, specifically being positioned and mounted by means of guide structures disposed on the clamp support  12  and housing  2 , and a snap-fit assembly  16  described below. The guide structures are configured to guide and mount the clamp support  12 , and the snap-fit assembly  16  is configured to fasten and release the clamp support  12 ; when the clamp support  12  is fastened, the clamping device  1  is fixed to the reciprocating saw housing  2 . The guide structures comprise a pair of guide ribs  124  (a first guide structure) disposed on inside walls of the clamp support  12  as shown in  FIG. 4 , the guide ribs  124  being formed opposite each other on inside walls of the connecting part  121  of the clamp support  12 ; opposite this, in corresponding positions at a front end of the housing  2 , a pair of guide grooves  24  (a second guide structure) corresponding to the guide ribs  124  is also provided on side walls of the housing  2 , and the clamping device  1  can be mounted quickly by means of the guiding action of the guide ribs  124  and guide grooves  24 . 
     As shown in  FIG. 2 , the snap-fit assembly  16  is mounted inside the housing  2 , close to the guide grooves  24 ; specifically, a button part  161  thereof is arranged to pass through two side walls of the housing  2 , a snap-fit part  162  (a second snap-fit structure) subjected to a pressing operation by means of the button part  161  is located inside the housing  2 , and a hole for a hook part  162   a  of the snap-fit part  162  to pass through is also provided in a top wall of the housing  2 .  FIGS. 5 and 6  show the specific structure of the snap-fit assembly  16 , as shown in the figures, the button part  161  comprises buttons  161   a ,  161   b , and a compression spring  161   c  located between  161   a  and  161   b . The compression spring  161   c  is configured to maintain the relative positions of the two buttons  161   a ,  161   b , and the snap-fit part  162  subjected to a pressing operation by means of the button part  161  is located between the two buttons. Pressing the button part  161  causes the hook part  162   a  thereof to hook and release a support part  125  (a first snap-fit structure, see  FIG. 4 ) of the clamp support  12 . 
     A body of the snap-fit part  162  in this embodiment is plate-like, one end part thereof being folded obliquely upwards to form the hook part  162   a . An angle between the hook part  162   a  and the body of the snap-fit part  162  is greater than 90°, being an obtuse angle; such a structure facilitates the mounting of the clamp support  12 . A connecting pin  162   b  is integrally formed at another end part of the snap-fit part  162 ; the connecting pin  162   b  may of course also be formed by another method such as welding. A gap  162   c  for mounting a torsion spring  162   e  is left between one end of the connecting pin  162   b  and the body of the snap-fit part  162 ; the gap  162   c  is of such a size as to be able to accommodate the torsion spring  162   e  fitted round the connecting pin  162   b . The snap-fit part  162  in this embodiment is moveably mounted on inner walls of the housing  2  by means of the connecting pin  162   b  and rotates; specifically, a pair of mounting holes is provided opposite each other in inner walls at two sides of the housing  2 , with two end parts of the connecting pin  162   b  being respectively mounted in the mounting holes, thereby mounting the snap-fit part  162  inside the housing  2 . End parts of the torsion spring  162   e  fitted round the connecting pin  162   b  abut the inner walls of the housing  2 , for the purpose of returning the snap-fit part  162  to its initial position. Oblique faces  162   d  are formed on two side faces of the snap-fit part  162  that are adjacent to the buttons  161   a ,  161   b ; the oblique faces  162   d  are a part of the side faces. The oblique faces  162   d  are pressed faces; preferably, the two oblique faces are formed to be inclined from two sides of the hook part  162   a.    
     The buttons  161   a ,  161   b  of the button part  161  are arranged to be inserted opposite each other; the button  161   a  and button  161   b  have guide parts  161   a - 1  and  161   b - 1  respectively, which are formed to extend towards each other from button bodies. The guide parts  161   a - 1  and  161   b - 1  are cylindrical structures fitting each other, wherein the internal diameter of the guide part  161   b - 1  is slightly larger than the external diameter of the guide part  161   a - 1 . The compression spring  161   c  is located inside the guide parts, and abuts the bodies of the two buttons. A guide rib  161   a - 2 , and an engagement slot  161   b - 2  fitting the guide rib  161   a - 2 , are also formed in an axial direction on outside walls of the guide parts  161   a - 1  and  161   b - 1  respectively. The buttons  161   a ,  161   b  also have pressing parts  161   a - 3 ,  161   b - 3  for pressing the snap-fit part  162 ; the pressing parts  161   a - 3 ,  161   b - 3  have pressing inclined faces for pressing the oblique faces  162   d  of the snap-fit part  162 . 
     In this embodiment, the process of action of the snap-fit assembly  16  is as follows. When the buttons  161   a ,  161   b  of the button part  161  are not subjected to a force application operation, the two buttons remain at a certain distance under the action force of the compression spring  161   c ; this certain distance is a distance at which rotation of the snap-fit part  162  does not encounter interference. At this time, quite a long part of the hook part  162   a  extends out of the housing  2 ; thus, if the clamping device  1  is mounted, the hook part  162   a  is in a state of hooking the support part  125  of the clamp support  12 . When the buttons  161   a ,  161   b  are pressed towards each other, the two buttons  161   a ,  161   b  approach each other, and the pressing inclined faces of the pressing parts  161   a - 3 ,  161   b - 3  thereof will respectively press the oblique faces  162   d  of the snap-fit part  162 , thus causing the snap-fit part  162  to rotate downwards (i.e. rotate away from the housing  2 ); the hook part  162   a  also rotates downwards therewith, thus no longer hooking the support part  125 , so the clamp support  12  and the clamp  11  thereon can be released. When the pressing operation on the buttons  161   a ,  161   b  is removed, the buttons  161   a ,  161   b  return to the certain distance mentioned above under the action of the elastic force of the compression spring  161   c . Under the action of the torsion spring  162   e , the snap-fit part  162 , which is no longer pressed, rotates back to its initial position where quite a long part of the hook part  162   a  extends out of the housing  2 . 
     A limiting structure for limiting the rotation range of the clamp  11  is also provided on the clamping device  1 . Specifically, an inclined face  123  sloping towards a rear end of the clamp support  12  is formed between the two plate-like connecting members of the connecting part  121  of the clamp support  12 ; opposite this, between the two connecting plates  111  of the clamp  11 , the upper end part of the clamp is bent away from the clamp support  12  to form a limiting part  113 . Thus, when the clamp  11  rotates to a maximum angle, the limiting part  113  and the inclined face  123  of the clamp support  12  abut each other to achieve limiting. 
     In this embodiment, a sawtooth-like structure may also be provided on a front side face (i.e. a side face that faces away from the housing  2 ) of the clamping claw  11   a  of the clamp  11 . Thus, when the clamping device  1  is not being used, the object to be cut  9  can also be abutted by using the sawtooth-like structure at the front side of the clamping claw  11   a , to perform a cutting operation. 
     In this embodiment, the mounting and clamping operations of the clamping device  1 , and the process of subsequently removing it, are specifically as follows. The fully assembled clamping device  1  is placed in front of the front end part  21  of the housing  2 , and the clamp support  12  is pushed rearwards along the position where the guide grooves  24  on the housing  2  are located. As it is pushed, the support part  125  on an inside face of the clamp support  12  comes into contact with the hook part  162   a  of the snap-fit part  162 . After continued pushing of the clamp support  12 , the snap-fit part  162  is caused to rotate downwards under the action of the pushing force of the support part  125 , and at the same time the hook part  162   a  is also caused to move downwards therewith, and the support part  125  thus crosses over the hook part  162   a . When the support part  125  has crossed over the hook part  162   a , the hook part  162   a  is no longer subjected to the force, and can return to its initial position under the action of the torsion spring  162   e , thus coming into abutment with the support part  125 , such that the clamp support  12  is fixed to the housing  2 . Mounting and positioning of the clamping device  1  is thus completed. 
     Next, the object to be cut  9  is clamped by means of the mounted clamping device  1  to perform the cutting operation. When the object to be cut  9  is received in the receiving region  23 , a user grips the reciprocating saw handle  8  and pulls the reciprocating saw towards the user&#39;s body (i.e. rearwards); the object to be cut  9  will then push the clamp jaw  11   b  and cause the clamp  11  to move from the closed position shown in  FIG. 1  to an open position shown in  FIG. 7 . In  FIG. 7 , the open position is a partially open position. In the open position, the clamp jaw  11   b  is no longer close to the receiving part  22 , because the object to be cut  9  is forcing the clamp  11  to open and move in the direction of the arrow in the figure. With further pushing, the object to be cut  9  will move closer to the cutting saw blade  6 , and due to the action of the torsion spring  14  on the clamp  11 , the object to be cut  9  is biased towards the closed position, and advances towards the cutting saw blade  6 , until it reaches a cutting position below the cutting saw blade  6 . When the object to be cut  9  is cut by the cutting saw blade  6 , the object to be cut  9  can be prevented from shaking, slipping and rotating, etc., because the clamp  11  clamps the object to be cut  9  in a stable fashion. Thus, even in the case where a cylindrical object to be cut  9  such as a branch or pipe is being cut, movement of the object to be cut  9  can be prevented effectively. 
     When cutting is complete, the clamping device  1  can be removed from the housing  2 . Furthermore, the clamping device may also not be removed, because the clamping device  1  lies against the housing  2  when not clamping the object to be cut  9 , so takes up little space and does not affect the transportation of the reciprocating saw. When it is necessary to remove the clamping device  1 , the buttons  161   a ,  161   b  are pressed; the snap-fit part  162  is pushed to rotate downwards by means of the pressing parts  161   a - 3 ,  161   b - 3  on the buttons, and the hook part  162   a  thereof rotates downwards therewith and no longer abuts the support part  125 . At this time, the clamping device  1  can be removed from the housing  2  by pulling the clamp support  12  away from a body of the reciprocating saw. 
     Embodiment 2 
     In this embodiment, a clamping device  1 ′ with a simpler structure than the clamping device  1  in embodiment 1 is further provided. The clamping device  1 ′ is mounted on the reciprocating saw body in the same position as in embodiment 1, also lies against a housing  2 ′ in a mounted state, and as in embodiment 1, is removable relative to the reciprocating saw machine body. In this embodiment, the manner of operation of the clamping device  1 ′ and the internal structure of the reciprocating saw are both the same as in embodiment 1, so will not be described again in embodiment 2. 
     As shown in  FIG. 8 , the clamping device in this embodiment comprises a clamp  11 ′ and a clamp support  12 ′; the structures of a clamping claw  11   a  and a clamp jaw  11   b  of the clamp  11 ′ are the same as those described in embodiment 1, so will not be described in detail again. In this embodiment, the clamp  11 ′ and the clamp support  12 ′ are also hinge-connected by means of a connecting pin  13 ′, and a torsion spring (not shown) is also fitted round the connecting pin  13 ′. 
       FIG. 9  is an exploded drawing of the clamping device of this embodiment. As shown in the figure, an upper end part of the clamp  11 ′ is hinge-connected to a front end of the clamp support  12 ′. Two left and right connecting plates  111 ′ are formed at the upper end part of the clamp  11 ′, the two connecting plates  111 ′ each being provided with a pin hole (not shown). Correspondingly, a connecting part  121 ′ fitting the connecting plates  111 ′ is formed at the front end of the clamp support  12 ′, the connecting part  121 ′ being provided with pin holes (not shown) corresponding to the pin holes in the connecting plates  111 ′. The clamp  11 ′ and clamp support  12 ′ are connected by means of a connecting pin  13 ′ passing through the pin holes, and a torsion spring fitted round the connecting pin  13 ′ is located inside the connecting part  121 ′. A middle part of a front end part of the clamp  11 ′ extends out towards the clamp support  12 ′ to form a limiting part  113 ′; during use, the limiting part  113 ′ performs limiting by abutting a front end of a guide rod  127  described below, and at the same time, correspondingly, a slot part  126  preventing interference with rotation of the limiting part  113 ′ is provided at an upper middle position of the clamp support  12 ′. One end of the torsion spring fitted round the connecting pin  13 ′ is engaged below the limiting part  113 ′ of the clamp  11 ′, and another end abuts the clamp support  12 ′. Furthermore, an annular groove (not shown, the same as in embodiment 1) for an elastic shaft retaining ring (not shown, the same as in embodiment 1) to snap into is provided at an end part of the connecting pin  13 ′. The clamp  11 ′, clamp support  12 ′ and torsion spring are connected together by means of the connecting pin  13 ′ and elastic shaft retaining ring, and the clamp  11 ′ can rotate and return to its initial position under the action of the torsion spring. When in the state of having returned to its initial position, the clamp  11 ′ of the clamping device lies against a front end part  21 ′ of the reciprocating saw housing. 
     The clamping device  1 ′ in this embodiment is also mounted at a front end of the machine body of the reciprocating saw. Specifically, a recess  21   a ′ for mounting the clamping device  1 ′ is left at a front end of the housing  2 ′; when mounting is complete, the clamp  11 ′ of the clamping device  1 ′ lies against the front end part  21 ′ of the housing  2 ′, with the connected parts of the clamp  11 ′ and clamp support  12 ′ being inserted into the recess. Such a design enables the clamping device  1 ′ to be mounted more securely on the reciprocating saw. An internal space  25  for accommodating the guide rod  127 , described below, of the clamp support  12 ′ is formed in the housing  2 ′ behind the recess  21   a′.    
     The clamp support  12 ′ in this embodiment is connected to the reciprocating saw machine body by means of a guide rod having an engagement slot structure at an extremity thereof. Specifically, the connecting part  121 ′ extends rearward away from the end of the clamp  11 ′ to form a pair of guide rods  127  (a first guide structure); the two guide rods are arranged opposite each other in a vertical direction, and are each provided with an engagement slot  127   a  (a first snap-fit structure) close to an extremity thereof. Correspondingly, a snap-fit structure and a guide structure fitting the guide rods  127  are also formed on the housing  2 ′. As shown in  FIG. 10 , the internal space  25  for mounting the guide rods  127  is formed inside the housing  2 ′. The internal space  25  is rectangular, having an insertion port  251  at an end close to the recess  21   a ′; the guide rods  127  enter the internal space  25  through the insertion port  251 . A guide post  26  (a second guide structure) is provided in the internal space  25  in such a way as to run through in a direction perpendicular or approximately perpendicular to the guide rod  127 . The guide post  26  preferably has a cylindrical structure, and a gap for the guide rod  127  to pass through is left between the guide post  26  and an inner wall of the housing  2 ′. The diameter of the guide post  26  is slightly smaller than the distance between the two guide rods  127 ; when mounting is complete, the two guide rods  127  are clamped at upper and lower sides of the guide post  26 . The guide post  26  provides a guiding action for mounting of the guide rods  127 , such that the clamping device can be mounted more easily; furthermore, the guide rods  127  are supported by the guide post  26 , so the mounting stability and force-bearing strength of the clamping device can be enhanced. In this embodiment, two guide posts are shown as being provided in the drawings, but the number of guide posts is not limited to two, one or more guide posts may be provided as required. 
     The guide rod  127  in this embodiment may be made of a metal material, or made of a plastic material. When a metal material is used, the thickness of the guide rod is 0.6 mm-2.4 mm, or 0.8 mm-2.0 mm, or 1 mm-1.8 mm, or 1.2 mm-1.5 mm, and is preferably about 1.3 mm. When a plastic material is used, the thickness of the guide rod is at least 1.3 mm, and preferably at least 3 mm, to ensure sufficient strength. Moreover, when the clamping device  1 ′ is operating, both the guide rod  127  and the housing at the position where the guide rod is located will be subjected to forces, so the housing  2 ′ must be thickened at this position (i.e. the position where the internal space  25  is located), in order to improve the force-bearing strength. 
     As shown in  FIG. 10 , a positioning pin assembly (a second snap-fit structure) is also mounted close to an extremity of the internal space  25 ; the positioning pin assembly comprises a positioning pin  27  and a compression spring  272  fitted round the positioning pin  27 . Two ends of the positioning pin  27  are moveably mounted on side walls of the housing  2 ′. As shown in  FIG. 10 , the positioning pin  27  comprises a positioning part  271  formed on a pin body of the positioning pin  27 , the positioning part  271  having a shape matched to the engagement slot  127   a  on the guide rod  127 , and preferably being cylindrical, the positioning of the clamp support  12 ′ is achieved by means of the snap-fitting of the positioning part  271  and the engagement slot  127   a . The compression spring  272  for returning the positioning pin  27  to an initial position is fitted round the pin body of the positioning pin  27 . The compression spring  272  is mounted on the pin body of the positioning pin  27  at a side remote from the guide rod  127 , and has one end in abutment with an inner wall of the housing  2 , and another end in abutment with the positioning part  271 . The clamp support  12 ′ can be fixed and positioned by means of the positioning pin  27 . The quantity and mounting position of the positioning pin  27  are not limited to those described in the embodiment, but may be adjusted according to circumstances. 
     In this embodiment, the mounting and removal processes of the clamping device  1 ′ are specifically as follows. The clamping device  1 ′ is placed in front of the front end part  21 ′ of the housing  2 ′ the guide rods  127  are aligned with the insertion port  251 , and the clamp support  12 ′ is pushed towards the internal space  25 . The two guide rods  127  pass through the gaps between the guide post  26  and the housing  2 , vertically clamping the guide post  26  from the upper side and the lower side respectively of the guide post  26 , thus entering the internal space  25 . When the guide rods  127  continue to be pushed and resistance is encountered (the positioning part  271  on the positioning pin  27  obstructs the guide rods  127 ), at this time, an end part of the positioning pin  27  at the side remote from the compression spring  272  is pressed, and the positioning pin  27  moves towards the side where the compression spring  272  is located under the action of the force; the positioning part  271  of the positioning pin  27  also moves back therewith to one side, thus moving out of the way, and the compression spring  272  is compressed. When the positioning part  271  has moved back out of the way, the clamp support  12 ′ is pushed slightly, at which time the connected parts of the clamp  11 ′ and the clamp support  12 ′ will also be inserted into the recess  21   a ′. The positioning pin  27  is then released, and the positioning pin  27  returns to its initial position under the action force of the compression spring  272 , such that the positioning part  271  is snap-fitted into the engagement slot  127   a  of the guide rod  127 , thus positioning the guide rod  127 . Mounting of the clamping device  1 ′ is thus completed. 
     When the reciprocating saw has been used, the clamping device  1 ′ may be removed from the reciprocating saw, but may also not be removed, as was the case in embodiment 1. When it must be removed, the positioning pin  27  is pressed such that the positioning part  271  thereof moves back out of the engagement slot  127   a ; the clamping device  1 ′ can then be removed from the housing  2 ′ by pulling the clamping device. 
     In this embodiment, the process of the clamping device  1 ′ clamping the object to be cut  9  is the same as in embodiment 1. 
     The present utility model also provides a fastening ring  61  for the reciprocating saw cutting saw blade  6  (as shown in  FIGS. 1 and 2 ); the cutting saw blade can be replaced quickly by means of the fastening ring  61 . In the prior art, multiple protrusions are generally provided in an axial direction at the periphery of the fastening ring  61 ; these protrusions help to prevent slipping when the fastening ring is being fastened and released, and can increase frictional resistance. However, with such a structure, it is not possible to exert a force effectively in operations like reciprocating saw cutting saw blade replacement, which require a large fastening force, so operational requirements can thus not be satisfied. To solve this problem, in this embodiment, a protrusion structure  611  enabling an operator to exert a force with a thumb is provided in an axial direction at the periphery of the fastening ring  61 . Preferably, two protrusion structures  611  are provided, the two protrusion structures  611  being arranged opposite each other in a circumferential direction at the periphery of the fastening ring  61 , and tooth-like protrusions for increasing frictional resistance are also provided on the protrusion structures  611  at a side where a force is exerted. The cutting saw blade  6  can be replaced more easily and quickly by means of the fastening ring with such a structure in the present utility model, and it is also possible to effectively prevent slipping, etc. when the fastening ring  61  is rotated, thus providing a further safety guarantee for the operator.