Abstract:
A pair of pruning shears is revealed. The pruning shears include a first brake arm, a second brake arm, a blade, and at least one connection piece. The first brake arm is disposed with a first toothed part while the second brake arm is arranged with a second toothed part. The first toothed part and the second toothed part are engaged with each other. The connection pieces are connected to the blade, the first brake arm, and the second brake arm. During a cutting process, a force applied is reduced due to the connection piece pivotally connected to the first brake arm and the second brake arm. While the first and the second toothed parts are engaged with each other, the connection piece becomes a wall of the first and the second toothed parts for stabilizing the engagement of the first and the second toothed parts.

Description:
NOTICE OF COPYRIGHT 
       [0001]    A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to any reproduction by anyone of the patent disclosure, as it appears in the United States Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. 
       BACKGROUND OF THE PRESENT INVENTION 
       [0002]    1. Field of Invention 
         [0003]    The present invention relates to pruning shears used in gardening, especially to pruning shears for trimming hard branches of trees, plants and fences. A stronger cutting force is required for pruning these plants so that the present invention provides a cutting structure with features of labor-saving and stability. 
         [0004]    2. Description of Related Arts 
         [0005]    Refer to EP1827770, a pair of clippers, especially hedge clippers, is revealed. Disclosed are manually operated clippers, especially hedge clippers, comprising a toothed gear (ZG, ZS) that is located between a first handle arm (GA 1 ) and a first clipper arm (S 1 ). The second handle arm (GA 2 ) is hingedly connected to the second clipper arm (S 2 ) while a coupling lever (HE) is provided between the second handle arm (S 2 ) and the first handle arm (GA 1 ) and/or the first clipper arm (S 1 ) such that the handle arms and the blades can be swiveled in a largely symmetrical manner when the clippers are opened and closed even though the coupling structure encompassing only one toothed gear (ZG, ZS) is asymmetrical. In addition, the entire amount of force that is transmitted between the actuated handle arms and the blades can be influenced via the coupling lever. The patent is related to a pair of manually operated clippers and the force transmitted between a brake handle arm and a blade can be reduced through a connecting rod. 
         [0006]    However, there is only one side of the engagement part between the toothed gears (ZG, ZS) being closed while the other side is opened, without any wall or covering. An upper end of the first dipper arm S 1  becomes a wall for closing one side of the engagement part between the toothed gears (ZG, ZS). During the trimming of hard branches of plants, the blades may be unable to fit each other closely and the cutting is not smooth. A reaction force split the blades is also transmitted to the toothed gears (ZG, ZS) therebetween. Thus the toothed gears (ZG, ZS) are against and separated from each other due to the reaction force. Therefore the toothed gears (ZG, ZS) are unable to engage with each other normally. In another condition, the hard branches of the plants may be inserted into the toothed gears (ZG, ZS) through the open side. This also results in that the toothed gears (ZG, ZS) are unable to mesh smoothly. 
       SUMMARY OF THE PRESENT INVENTION 
       [0007]    Therefore it is a primary object of the present invention to provide a pruning shears that is more labor-saving and stable during cutting process. The pruning shears is a labor-saving device that combines a gear transmission device, linkage and lever. A first brake arm and a second brake arm are acted and moved stably by engagement of a first toothed part with a second toothed part. Furthermore, a first connection piece and a second connection piece are used to support the first brake arm and the second brake arm for increasing force transmitted. 
         [0008]    In order to achieve the above object, a pruning shears of the present invention includes a first brake arm, a second brake arm, a blade, a first connection piece, and a second connection piece. The first brake arm is formed by a first toothed part and a first handle part while the second brake arm is arranged with a second toothed part and a second handle part. The first toothed part and the second toothed part are engaged with each other. One end of the first connection piece is connected to the blade while the other end thereof is pivotally connected to the second brake arm. The first connection piece is used as a link. One end of the second connection piece is pivotally connected to the first brake arm while the other end thereof is pivotally connected to the second brake arm. The second connection piece is used as a lever so as to reduce the force required during cutting of the blade. Moreover, the projecting part of the blade and the second connection piece work as walls covering the first toothed part and the second toothed part during engagement so as to stabilize the engagement of the first toothed part with the second toothed part. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein: 
           [0010]      FIG. 1  is an explosive view of an embodiment according to the present invention; 
           [0011]      FIG. 2  is a front view of an embodiment according to the present I invention; 
           [0012]      FIG. 3  is a rear view of an embodiment according to the present I invention; 
           [0013]      FIG. 4  is a schematic drawing showing an embodiment being opened according to the present I invention; 
           [0014]      FIG. 5  is another schematic drawing showing an embodiment being opened according to the present I invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0015]    Refer to  FIG. 1 ,  FIG. 2  and  FIG. 3 , a pruning shears of the present invention includes a first brake arm  1 , a blade  2 , a first connection piece  4 , a second connection piece  5  and a second brake arm  6 . The first brake arm  1  consists of a first toothed part  13 , a first handle part  12  and a blunt part  11 . An axial part  14  and a stopping part  15  are disposed under the blunt part  11  while the first toothed part  13  is arranged between the blunt part  11  and the first handle part  12 . The second brake arm  6  is formed by a second handle part  61 , a second toothed part  62 , and a first assembly part  63  set between the second handle part  61  and the second toothed part  62 . The first toothed part  13  and the second toothed part  62  are engaged with each other. The blade  2  includes a connection part  22 , a first assembly part  23 , a second assembly part  24 , a blade part  25 , and a projecting part  26 . The first assembly part  23  and the second assembly part  24  are arranged at the connection part  22 . The connection piece  4  includes a first pivot part  41  and a second pivot part  42  while the second connection piece  5  consists of a third pivot part  51  and a fourth pivot part  52 . A bolt  72  is inserted through the second assembly part  24  of the blade  2  and the first pivot part  41  of the connection piece  4  and then is riveted. The second pivot part  42  of the connection piece  4  is pivotally connected to the first assembly part  63  of the second brake arm  6  by a bolt  73  passed therethrough. A bolt  71  is first inserted through the first assembly part  23  of the blade  2 , then passed through the first axial part  14  of the first brake arm  1 , the third pivot part  51  of the second connection piece  5  and a ring fastener  32  to be fastened by a nut  75 . After being inserted through the first assembly part  63  of the second brake arm  6 , the bolt  73  is further passed through the fourth pivot part  52  of the second connection piece  5  and a ring fastener  31  to be screwed into a nut  74 . 
         [0016]    Refer to  FIG. 4 ,  FIG. 5  and  FIG. 6 , the projecting part  26  of the blade  2  and the second connection piece  5  clip the first toothed part  13  and the second toothed part  62  therebetween. The projecting part  26  of the blade  2  becomes a front wall covering the engaged first toothed part  13  and the second toothed part  62  while the second connection piece  5  is a rear wall on the opposite side. When the first toothed part  13  and the second toothed part  62  are engaged with other, the clipping of the projecting part  26  of the blade  2  and the second connection piece  5  can stabilize the engagement between the first toothed part  13  and the second toothed part  62  and keep the engagement therebetween running smoothly. It should be noted that the second connection piece  5  can be moved like a pendulum. While the first toothed part  13  is engaged with the second toothed part  62 , the second connection piece  5  is also moved along with the engagement part where the first toothed part  13  and the second toothed part  62  are engaged with each other for covering the engagement part. 
         [0017]    The first pivot part  41  of the connection piece  4  is connected to the second assembly part  24  of the blade  2  in a fixed manner and unable to pivot while the second pivot part  42  of the connection piece  4  is pivotally connected to the first assembly part  63  of the second brake arm  6  and able to turn on pivotally. The assembly of the second assembly part  24  of the blade  2  with the first pivot part  41  of the first connection piece  4  is by the bolt  72  passed therethrough and then to be riveted while the bolt  73  is inserted through the second pivot part  42  of the connection piece  4  and the first assembly part  63  of the second brake arm  6  for pivotal connection. Moreover, due to that the first connection piece  4  is connected to the second brake arm  6  and riveted to the second assembly part  24  of the blade  2 , unable to turn on pivotally, the first connection piece  4  not only connects the blade  2  and the second brake arm  6 , but also shortens a push stroke of the second brake arm  6  that pushes the blade  2 . 
         [0018]    As shown in  FIG. 6 , the present invention features on that the movement and the engagement between the first toothed part  13  and the second toothed part  62  are stabilized by the second connection piece  5  and the projecting part  26  of the blade  2 . The projecting part  26  of the blade  2  and the second connection piece  5  form a front wall and a rear wall respectively, covering the first toothed part  13  and the second toothed part  62  therebetween. The first connection piece  4  is connected to the blade  2  and the second brake arm  6  so that the first connection piece  4  becomes a crank extended from the blade  2 . The second pivot part  42  is pivotally connected to the second brake arm  6  so that the second brake arm  6  becomes a lever of the first connection piece  4 . Thus the first connection piece  4  can push the connection part  22  of the blade  2 . Therefore the open and close stoke is shortened and the force required for cutting is reduced when the second brake arm  6  and the first brake arm  1  are opened or closed for pruning. At the same time, the first connection piece  4 , together with the first brake arm  1  and the second brake arm  6  forms a linkage structure so as to save labor. The second connection piece  5  supports the first brake arm  1  and the second brake arm  6  to increase the force transmitted. The design and the structure allow the cutting process more labor saving and stable and this is another structural features of the present invention. 
         [0019]    Furthermore, the pruning shears of the present invention is designed based on the linkage and lever. The second connection piece  5  is a link and the second brake arm  6  is a rocker. Two ends of the first connection piece  4  are connected to the blade  2  and the second brake arm  6  respectively. The actuating path the second brake arm  6  can push or pull is extended. When the second brake arm  6  works as a link, the third pivot part  51  is the fulcrum. When a force is applied to the second brake arm  6 , the engagement part where the first toothed part  13  and the second toothed part  62  are engaged is the fulcrum. When the second handle part  61  of the second brake arm  6  is driven to move, the first toothed part  13  and the second toothed part  62  are engaged. The second connection piece  5  is relatively moved in a pendulum manner. At the same time, the first connection piece  4  pivotally connected to the second handle part  61  of the second brake arm  6  is also pushed to move and against the blade  2 . Thus the blade  2  is wobbled and moved to cut. The fulcrum for the blade  2  is the first assembly part  23  while the second assembly part  24  under the fulcrum is the point the force is applied. That means the first connection piece  4  pushes the connection part  22  of the blade  2  under the fulcrum. The connection part  22  is the lever arm while the first connection piece  4  is pushed by the second brake arm  6 . By the stroke the second brake arm  6  pushes the blade  2  and the first connection piece  4  pivotally connected to the second brake arm  6 , the force applied to the second handle part  61  and the first handle part  12  of the first brake arm  1  is reduced. In other words, while the second brake arm  6  and the first brake arm  1  are opened and closed for cutting, the pivotally connection position of the first pivot part  41  (the second assembly part  24 ) is lower than that of the first assembly part  63  (the second pivot part  42 ) in the view of the horizontal plane. Thus the first connection piece  4  having one end fixed on the second assembly part  24  of the blade  2  and the other end pivotally connected to the first assembly part  63  of the second brake arm  6  forms a lever between the blade  2  and the second brake arm  6 . 
         [0020]    The first assembly part  63  is used for connecting the second brake arm  6 . By the first connection piece  4  extended and coupled to the connection part  22  of the blade, the first connection piece  4  becomes a crank of the blade  2  and the length of the lever arm of the blade  2  is increased. Together with the length of the lever arm of the second brake arm  6 , the total length of the lever arm is larger than the length of the resistance lever arm of the blade  2  (the blade part  25 ). Thus the force required for operating the second brake arm  6  is significantly reduced. 
         [0021]    In addition, the stopping part  15  under the blunt part  11  provides the stopping function. As shown in  FIG. 2 , the pruning shears are closed. The connection part  22  of the blade  2  is pushed toward the first handle part  12  by the second handle part  61  and is unable to be moved any more until the connection part  22  is in contact with the stopping part  15 . The closing movement between the blade  2  and the blunt part  11  is finished. 
         [0022]    Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, and representative devices shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.