Patent Publication Number: US-2009227411-A1

Title: Power Device for an Electric Grease Gun

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electric grease gun, and more particularly to a power device for an electric grease gun with low abrasion and high precision. 
     2. Description of the Prior Art 
     In order to maintain the operation smoothness of a mechanical structure, lubricating oil is usually provided between the components of the structure to reduce friction. In order to reduce the manual effort, an electric grease gun  10  appeared in the market as shown in  FIG. 1 , which comprises a bearing seat  11 . One side of the bearing seat  11  is provided with a power device  20 , and the other side of the bearing seat  11  is provided with a receiving device  12  for reception of grease. The power device  20  comprises a gear reduction device  21  connected to the power source. The gear reduction device  21  is connected to an eccentric wheel  13 , and the eccentric wheel  13  is eccentrically combined with a screw  14  which drives a sliding block  15  to move. The sliding block  15  is combined with a pushing rod  16  which pushes grease. The gear reduction device  21  comprises a motor  22  and a plurality of reduction gear sets  23 . However, such a conventional electric grease gun still has the following disadvantages: 
     The reduction gear sets  23  are abutted against one another, once the motor  22  rotates the reduction gear sets  23  to reduce the rotating speed, the abrasion caused by the friction of the reduction gear sets  23  will cause the relative movement of the reduction gear sets  23 . As a result, the problem of inaccurate positioning is produced, such that the reduction gear sets  23  are unable to perform speed reduction precisely, and the life of the reduction gear sets  23  will be reduced. Moreover, the replacement and maintenance of the reduction gear sets  23  is also a headache for the user. 
     The present invention has arisen to mitigate and/or obviate the afore-described disadvantages. 
     SUMMARY OF THE INVENTION 
     The primary objective of the present invention is to provide a power device for an electric grease gun which realizes the effect of low abrasion and high precision via a positioning bearing. 
     To achieve the objective of the present invention, the power device for an electric grease gun comprises a first planetary disk, a first planetary gear set, a positioning bearing, a second planetary disk, a second planetary gear set and a ring gear. 
     One end of the first planetary disk is formed with a combining portion. 
     The first planetary gear set is pivotally disposed on the first planetary disk. 
     The second planetary disk is assembled corresponding to the first planetary disk, and the positioning bearing is pivotally disposed between the first and second planetary disks. The combining portion of the first planetary disk is inserted in the second planetary disk. One end of the second planetary disk is formed with a combining portion engaged with a feeding device. 
     The second planetary gear set is pivotally disposed on the second planetary disk and is engaged with the combining portion of the first planetary disk. 
     The ring gear is defined with a through hole for receiving the first and second planetary disks. The first and second planetary gear sets rotate in the ring gear. 
     The other end of the first planetary disk is formed with a first assembling portion, and the first assembling portion is formed with a second assembling portion for insertion of a transmission part of the motor. The first planetary disk is formed with at least one groove. The first planetary gear set comprises at least two-planetary gears that are pivotally disposed in the groove of the first planetary disk via a bolt, such that the planetary gears of the first planetary gear set are engaged with the transmission portion of the motor. 
     The positioning bearing comprises an inner ring and an outer ring. The inner ring is disposed on the outer ring, and a plurality of rolling members is provided between the inner ring and the outer ring. 
     The other end of the second planetary disk is formed with at least one receiving portion for receiving the positioning bearing, and the outer ring of the positioning bearing is abutted against the receiving portion. In addition, the inner ring of the positioning bearing is abutted against the first planetary disk, and the combining portion of the first planetary disk is inserted in the receiving portion of the second planetary disk. The second planetary disk is formed with at least one groove. 
     The second planetary gear set comprises at least two planetary gears that are pivotally disposed in the groove of the second planetary disk via a bolt, such that the planetary gears of the second planetary gear set are engaged with the combining portion of the first planetary disk. 
     An inner periphery of the ring gear is engaged with the planetary gears of the first and second planetary gear sets. 
     With the relative movement of the positioning bearing which is located between the first and second planetary disks, the first and second planetary disks can be positioned on the positioning bearing to change the rotating speed as desired. Moreover, the rolling members of the positioning bearing are used to reduce friction, such that the abrasion between the first and second planetary disks is reduced, and the life of the power device is prolonged. 
     The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiments in accordance with the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view of a conventional electric grease gun; 
         FIG. 2  is a perspective view of an electric grease gun in accordance with the present invention; 
         FIG. 3  is an exploded view of a power device and a bearing seat in accordance with the present invention; 
         FIG. 4  is an assembly perspective view of the power device in accordance with the present invention; and 
         FIG. 5  is an exploded view of a feeding device and the bearing seat in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIGS. 2 and 3 , a power device  30  for an electric grease gun in accordance with the present invention comprises a motor  31 , a first planetary disk  32 , a first planetary gear set  33 , a positioning bearing  34 , a second planetary disk  35 , a second planetary gear set  36 , a ring gear  37  and two restricting bearings  38 . 
     The motor  31  comprises a stator and a mover. The mover magnetically moves with respect to the stator. An axis passes through the mover of the motor  31 , and one end of the axis is provided with a transmission part  311 . Around the outer periphery of the transmission part  3   11  is formed a toothed surface  312 . 
     One end of the first planetary disk  32  is formed with a first assembling portion  321  which is in the form of a hollow cylinder, and a second assembling portion  322  which is in the form of hole and is provided for insertion of the transmission part  311  of the motor  31  being coaxial with the first assembling portion  321 . Both sides of the first planetary disk  32  are formed with a groove  323  in communication with the second assembling portion  322 . The other end of the first planetary disk  32  is formed with a combining portion  324  which is in the form of a hollow cylinder. Around the outer periphery of the combining portion  324  is formed a toothed surface  325 . 
     The first planetary gear set  33  comprises two planetary gears  331 ,  332  that are pivotally disposed in the grooves  323  of the first planetary disk  32  via bolts  333 ,  334 , such that the planetary gears  331 ,  332  are engaged with the toothed surface  312  of the transmission portion  311  of the motor  31 . 
     The positioning bearing  34  comprises an inner ring and an outer ring. An outer periphery of the inner ring is slidably disposed on an inner periphery of the outer ring, and a plurality of rolling members (such as ball or roller) (not shown) is provided between the inner ring and the outer ring. 
     One end of the second planetary disk  35  is formed with a first receiving portion  351  which is in the form of a hollow cylinder, and a second receiving portion  352  which is in the form of hole being coaxial with the first receiving portion  351 . An inner diameter of the first receiving portion  351  is larger than that of the second receiving portion  352 . The first receiving portion  351  is provided for receiving the positioning bearing  34 . The outer ring of the positioning bearing  34  is abutted against the inner periphery of the first receiving portion  351 , and the inner ring of the positioning bearing  34  is abutted against the first planetary disk  32 . The combining portion  324  of the first planetary disk  32  is inserted in the second receiving portion  352  of the second planetary disk  35 . Both sides of the second planetary disk  35  are formed with a groove  353  in communication with the second receiving portion  352 . The other end of the second planetary disk  35  is formed with a combining portion  354  which is in the form of a hollow cylinder. 
     The second planetary gear set  36  comprises two planetary gears  361 ,  362  that are pivotally disposed in the grooves  353  of the second planetary disk  35  via bolts  363 ,  364 , such that the planetary gears  361 ,  362  are engaged with the toothed surface  325  of the combining portion  324  of the first planetary disk  32 . 
     Referring to  FIG. 4 , the ring gear  37  is defined with a through hole  371 , and around the inner periphery of the through hole  317  is formed a toothed surface  372 . The through hole  371  of the ring gear  37  is provided for receiving the first and second planetary disks  32 ,  35 , such that the planetary gears  331 ,  332  of the first planetary gear set  33  and the planetary gears  361 ,  362  of the second planetary gear set  36  are engaged with the toothed surface  372  of the ring gear  37 , respectively. 
     Each of the restricting bearings  38 ,  39  comprises an inner ring and an outer ring. An outer periphery of the inner ring is slidably disposed on an inner periphery of the outer ring, and a plurality of rolling members (such as ball or roller) (not shown) is provided between the inner ring and the outer ring. The inner ring of the restricting bearing  38  is provided for insertion of the first assembling portion  321  of the first planetary disk  32 , and the inner ring of the restricting bearing  39  is provided for insertion of the combining portion  354  of the second planetary disk  35 . 
     Referring to  FIGS. 3-5 , the electric grease gun comprises a bearing seat  40  having a first assembling portion  41 , a second assembling portion  42  and a third assembling portion  43 . The first assembling portion  41  is connected to the second assembling portion  42 , and the third assembling portion  43  is mounted at an upper portion of the first and second assembling portions  41 ,  42 . 
     The first assembling portion  41  is provided for assembling the power device  30 . 
     The second assembling portion  42  is provided for assembling a feeding device  50 . Referring to  FIG. 5 , the feeding device  50  comprises a first rotating block  51 , an inserting rod  52 , a second rotating block  53  and a pushing rod  54 . The first rotating block  51  is defined with a positioning hole  511  and an eccentric hole  512 . The positioning hole  511  is located in the center of the first rotating block  51  and is provided for insertion of the combining portion  354  of the second planetary disk  35 . The eccentric hole  512  is located beside the positioning hole  511  and is provided for insertion of the inserting rod  52 . One end of the inserting rod  52  is inserted in the eccentric hole  512  of the first rotating block  51 , and the other end of the inserting rod  52  is inserted in the second rotating block  53 . The second rotating block  53  is defined with a restricting hole  531  for insertion of the other end of the inserting rod  52 . In an outer periphery of the second rotating block  53  is formed an assembling portion  532  which comprises two opposite hooks. The assembling portion  532  of the second rotating block  53  is engaged with the pushing rod  54 . One end of the pushing rod  54  is formed with an engaging portion  541  engaged in the assembling portion  532  of the second rotating block  53 . The third assembling portion  43  is provided for assembling an oil container  60 . 
     The feeding device  50  of the electric grease gun is driven by the power device  30  to press against the oil container  60 , so as to supply grease. 
     For a better understanding of the present invention, its operations and functions, reference should be made to  FIGS. 2-5  again: 
     The power device  30  is pivotally disposed on the bearing seat  40  via the restricting bearings  38 ,  39 . When the user drives the motor  31 , the toothed surface  312  of the transmission part  311  of the motor  31  will drive the planetary gears  331 ,  332  of the first planetary gear set  33  to rotate, such that the first planetary disk  32  will rotate in the ring gear  37 , so as to perform a first speed reduction. 
     When the first planetary disk  32  rotates, the toothed surface  325  of the combining portion  324  of the first planetary disk  32  will drive the planetary gears  361 ,  362  of the second planetary gear set  36  to rotate, such that the second planetary disk  35  will rotate in the ring gear  37 , so as to perform a second speed reduction. 
     With the relative movement of the inner ring and the outer ring of the positioning bearing  34  which is located between the first and second planetary disks  32 ,  35 , the first and second planetary disks  32 ,  35  can be positioned on the positioning bearing  34  to change the rotating speed as desired. Moreover, the rolling members of the positioning bearing  34  are used to reduce friction, such that the abrasion between the first and second planetary disks  32 ,  35  is reduced. 
     To summarize, a power device for an electric grease gun of the present invention comprises a first planetary disk, a first planetary gear set, a positioning bearing, a second planetary disk, a second planetary gear set and a ring gear. The first planetary gear set is pivotally disposed on the first planetary disk. The second planetary disk is assembled corresponding to the first planetary disk. The positioning bearing is pivotally disposed between the first and second planetary disks. The second planetary gear set is pivotally disposed on the second planetary disk and is engaged with the first planetary disk. The ring gear is defined with a through hole for receiving the first and second planetary disks. The first and second planetary gear sets rotate in the ring gear via the positioning bearing, so as to perform speed reduction. In addition, the positioning bearing is used to reduce friction. 
     While we have shown and described various embodiments in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.