Patent Publication Number: US-2017361386-A1

Title: Reciprocating tool

Description:
BACKGROUND 
     Field of the Invention 
     The invention relates to a Power tool, and more particularly to a reciprocating tool. 
     Related Prior Art 
     Power tools can be categorized into pneumatic tools and electric tools. The power reciprocating tools sold available on the market normally employ a crankshaft to convert the rotary motion of the motor into a repeated liner motion along a specific direction. However, these conventional Power reciprocating tools have many disadvantages, for example, low speed of reciprocating motion, big energy loss in the process of energy conversion, too large invalid power and etc. Therefore, it is urgent to develop a reciprocating tool which is converting the rotary kinetic energy of a motor into a repeatedly back and forth motion along a specific direction, to improve work efficiency. 
     SUMMARY 
     One objective of the present invention is to provide a high efficient reciprocating tool. 
     To achieve the above objective, the reciprocating tool in accordance with the present invention comprises: 
     a drive motor including a motor gear at one end of the drive motor; 
     a drive shaft which is rotated by the motor gear and extends along an axial direction, the drive shaft is composition of a ball rolling groove which is a rotary closed loop formed around the front end shaft, an extending direction of the ball rolling groove includes a component vector along the axial direction and a component vector around the front end shaft; 
     a driven shaft which is composition of a connecting end to connect a tool and an insertion section, the insertion section includes an inner round operation recess, the drive shaft is inserted into the inner round operation recess of driven shaft and rotating respect to the insertion section, the insertion section with at least one positioning surface on outer surface, and the insertion section with a ball hole; 
     a sliding member disposed into the ball hole of driven shaft and the ball rolling groove of drive shaft, when the drive shaft rotates, the sliding member will move along the ball rolling groove; 
     an annular fixing member, with at least one restricting surface on inner peripheral surface, the annular fixing member is sleeved onto the insertion section of the driven shaft, and the restricting surface is abutted against the positioning surface on driven shaft; and 
     a shell which is used to accommodate the drive motor, the drive shaft, the driven shaft, the sliding member, and the annular fixing member; 
     by means of swing arm, rotation of the drive shaft can cause movement of the sliding member along the ball rolling groove, for the restriction of annular fixing member, the driven shaft is driven to move back and forth repeatedly along the axial direction. 
     It can be learned from the above description that the invention employs the motor gear of the drive motor to rotate the drive shaft. When the drive shaft rotates, the sliding member disposed into the ball rolling groove will move along the path of the ball rolling groove, and at the same time, for the restriction of annular fixing member, the component of force of the sliding member in the axial direction pushes the driven shaft to move back and forth repeatedly along the axial direction, so that the tool fixed on the driven shaft also moves back and forth repeatedly in the axial direction, and thus a high efficient reciprocating tool is achieved. 
     These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view of a reciprocating tool in accordance with a preferred embodiment of the invention; 
         FIG. 2  is a perspective view of the drive shaft of the reciprocating tool in accordance with the preferred embodiment of the invention; 
         FIG. 3  is a perspective view of the driven shaft &amp; sliding member of the reciprocating tool in accordance with the preferred embodiment of the invention; 
         FIG. 4  is a perspective view of the annular fixing member of the reciprocating tool in accordance with the preferred embodiment of the invention; 
         FIG. 5  is a side view of the drive shaft of the reciprocating tool in accordance with the preferred embodiment of the invention; 
         FIG. 6  is a side view of a part of the reciprocating tool in accordance with the preferred embodiment of the invention; 
         FIG. 7  is another side view of a part of the reciprocating tool in accordance with the preferred embodiment of the invention; 
         FIG. 8  is an exploded view of a reciprocating tool in accordance with another preferred embodiment of the invention; and 
         FIG. 9  is an exploded view of a reciprocating tool in accordance with another preferred embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     The invention will be clearer from the following description when viewed together with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment in accordance with the invention. 
     Referring to  FIGS. 1-9 , the reciprocating tool in accordance with the preferred embodiment of the invention comprises: a drive motor  10 , a gear box  20 , a gear set  30 , a drive shaft  40 , a driven shaft  50 , two bearings  60   60 A, a sliding member  70 , at least one assistant sliding member  70 A, an annular fixing member  80 , an elastic member  90 , an outer cover L, and an outer shell M. 
     The drive motor  10  includes a motor gear  11  at one end of the drive motor  10 . 
     The gear box  20  is connected to the end of the drive motor  10  where the motor gear  11  is provided. The gear box  20  includes a connecting peripheral wall  21  with a plurality of spaced-apart engaging grooves  211 , and the connecting peripheral wall  21  defines a receiving space  20 A. 
     The gear set  30  includes a ring gear  31  and at least two planetary gears  32 . The ring gear  31  is an annular ring disposed into the gear box receiving space  20 A and includes an inner peripheral surface  311  and an opposite outer peripheral surface  312 . A plurality of spaced-apart engaging ribs  312 A is formed on the outer peripheral surface  312  to engage with the engaging grooves  211 , so that the ring gear  31  is engaged in the gear box receiving space  20 A. A plurality of drive teeth  311 A is formed around the inner peripheral surface  311 . The planetary gears  32  are engaged with the motor gear  11  and are disposed into and also engaged with the drive teeth  311 A of the ring gear  31 . In this embodiment, there are two planetary gears  32 . 
     The drive shaft  40  is composition of a front end shaft  41 , a receiving section  42  and a bearing section  43 . The front end shaft  41  with a ball rolling groove  411  which is a rotary closed loop formed around the front end shaft  41 . An extending direction of the ball rolling groove  411  includes a component vector along the axial direction X and a component vector around the front end shaft  41 . The receiving section  42  has a diameter larger than a diameter of the front end shaft  41  and a diameter of the bearing section  43 . The receiving section  42  includes at least two receiving cavities  421 , and the planetary gears  32  are disposed into the receiving cavities  421  to rotate the drive shaft  40 . One end of the receiving section  42  connected to the front end shaft  41  with an abutting surface  422 . 
     The driven shaft  50  is composition of a connecting end  51 , a stop flange  52  and an insertion section  53 . The connecting end  51  includes a connecting groove  511  to connect a tool K. The insertion section  53  is a hollow cylinder with an inner round operation recess  531 . The front end shaft  41  of drive shaft can be inserted into the inner round operation recess  531  and rotating respect to the insertion section  53 . the insertion section  53  with at least one positioning surface  53 A on outer surface. The insertion section  53  with a ball hole  532  and at least one guiding slot  533  which extend along the axial direction X. The ball hole  532  and the guiding slot  533  are formed on the insertion section  53  and are not located at the positioning surface  53 A. Preferably, in this embodiment, there are two positioning surfaces  53 A. The insertion section  53  consists of the two spaced-apart positioning surfaces  53 A and two spaced-apart arc-shaped surfaces  53 B with an alternate manner on outer surface. The two arc-shaped surfaces  53 B are arranged in an opposite manner. The ball hole  532  is located at one of the arc-shaped surfaces  53 B, and the guiding slot  533  is located at another one of the arc-shaped surfaces  53 B. In this embodiment, the tool K can be a knife tool or a hammer tool. Preferably, each of the two positioning surfaces  53 A is provided with at least one cushion-roller groove U for accommodation of a cushion roller U 1  as shown in  FIG. 9 . 
     The bearings  60  is sleeved onto the front end shaft  41  and abutted against the abutting surface  422 . Another one bearings  60 A is sleeved onto the bearing section  43 , and the bearing  60 A has its outer ring portion installed in the receiving space  20 A. With the two bearings  60   60 A, the drive shaft  40  is capable of rotating with respect to the driven shaft  50 . When the drive shaft  40  is rotated by the drive motor  10 , the driven shaft  50  won&#39;t rotate synchronously with the drive shaft  40 , for the restriction of annular fixing member. 
     The sliding member  70  is disposed into the ball hole  532  and the ball rolling groove  411 . When the drive shaft  40  rotates, the sliding member  70  will move annularly along the ball rolling groove  411 . Since the extending direction of the ball rolling groove  411  includes a component along the axial direction X and a component around the front end shaft  41 , when the sliding member  70 , moving annularly along the ball rolling groove  411 , will produce a component of force along the axial direction X and a component of force around the drive shaft  40 . Besides, the driven shaft  50  does not rotate with the drive shaft  40 , for the restriction of annular fixing member, therefore, the sliding member  70  located in the ball hole  532  is only able to transmit the component of force in the axial direction X to the driven shaft  50 , which will cause reciprocating displacement of the driven shaft  50  along the axial direction X with respect to the drive shaft  40 . In this embodiment, the sliding member  70  can be a rolling ball or, a cylinder with a round end or arc-shaped end. 
     The at least one assistant sliding member  70 A is disposed into the guiding slot  533 , each guiding slot  533  is provided with at least one assistant sliding member  70 A, so that the driven shaft  50  can move more smoothly in the axial direction X and can be prevented from arbitrary rotation. In this embodiment, the assistant sliding member  70 A can be a rolling ball or, a cylinder with a round end or arc-shaped end. 
     The annular fixing member  80  is a hollow cylinder, with at least one restricting surface  80 A on inner round surface. The annular fixing member  80  is sleeved onto the insertion section  53  on the driven shaft  50 , and the restricting surface  80 A is abutted against the positioning surface  53 A to prevent the driven shaft  50  from rotating, which can also prevent the sliding member  70  falling off from the ball hole  532 , and prevent the assistant sliding member  70 A falling off from the guiding slot  533 . Besides, when the driven shaft  50  moves, the cushion roller U 1  between the restricting surface  80 A and positioning surface  53 A to enhance the smoothness of movement of the driven shaft  50  while reducing friction caused loss. Preferably, the annular fixing member  80  with an annular abutting flange  81 , which is located at one end of the annular fixing member  80  toward the receiving section  42 . The annular fixing member  80  includes an inner hole  82 , to locate outer ring surface of the bearing  60 , the bearing  60  sleeved onto the front end shaft  41 . 
     The elastic member  90  is sleeved on the annular fixing member  80 , and has two ends pushed against the annular abutting flange  81  and the stop flange  52 , respectively, to eliminate the interval between the sliding member  70  and the ball rolling groove  411 . 
     The outer cover L is sleeved onto the connecting end  51  to make sure the tool K is inserted stably and firmly in the connecting groove  511 . 
     The shell M is used to accommodate the drive motor  10 , the gear box  20 , the gear set  30 , the drive shaft  40 , the driven shaft  50 , the two bearings  60   60 A, the sliding member  70 , the assistant sliding member  70 A, the annular fixing member  80 , and the elastic member  90 . 
     What mentioned above are the main components of the reciprocating tool in the invention, and for a better understanding of the operation and function of the embodiment of the invention, reference the following description with  FIGS. 1-9 . 
     When in use, the motor gear  11  of the drive motor  10  rotates the planetary gears  32 , and then the planetary gears  32  transmit kinetic energy to the drive shaft  40  to cause rotation of the drive shaft  40 . When the drive shaft  40  rotates, the sliding member  70  disposed into the ball rolling groove  411  will move along the path of the ball rolling groove  411 , and at the same time, for the restriction of annular fixing member, the component force of the sliding member  70  in the axial direction X pushes the driven shaft  50  to move back and forth repeatedly along the axial direction, so that the tool K fixed on the driven shaft  50  also moves back and forth repeatedly in the axial direction X. 
     There is a gear reducing system at the reciprocating tool of the invention. The gear set  30  between the drive shaft  40  and the drive motor  10 , It makes the lower speed output of the drive shaft  40  than the speed of drive motor  10 , so as to stabilize the speed of the back and forth motion of the driven shaft  50 . 
     Besides, the annular fixing member  80  with the at least one restricting surface  80 A on the inner peripheral surface, to abut against the at least one positioning surface  53 A on the outer peripheral surface of the insertion section  53 , so as to prevent the driven shaft  50  from rotating. 
     Furthermore, the ball rolling groove  411  is in the form of a rotary closed loop, which allows the sliding member  70  to circulate along the ball rolling groove  411 , so that the driven shaft  50  can move back and forth repeatedly along the axial direction X. 
     While we have shown and described various embodiments in accordance with the invention, it is clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.