Abstract:
The present invention relates to a guide rail for a power tool with an auxiliary guide component having a locating block and a main guide component. The guide rail has a fixing device to connect the auxiliary guide component to the main guide component. The locating block has a taper-tilted edge that may be connected to a corresponding edge of the fixing device. Using the tapered fitting, the main guide component and the auxiliary guide component can be quickly connected or disconnected to adjust the positions of the auxiliary guide component and the main guide component during operation. The present invention may further include angle-indication marks. By setting the angle-indication marks on the auxiliary guide component, cutting at a certain angle can be achieved quickly to improve the convenience and efficiency of operation by the user.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to Chinese Application No. 200920049322.X, filed on Oct. 12, 2009 and Chinese Application No. 200920049342.7 filed on Oct. 13, 2009, which are hereby incorporated by reference. 
       FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable. 
       TECHNICAL FIELD 
       [0003]    The present invention relates to a guide rail for a power tool. 
       BACKGROUND OF THE INVENTION 
       [0004]    Hand-held power tools, especially saws having circular saw blades, are difficult to use for cutting in a straight line unless the saw is being used by an experienced user. Further, cutting a smooth curve is difficult for even an experienced user without using a guide to assist the user. 
         [0005]    In order to guide a hand-held saw, such as a circular saw, a reciprocating saw, a jig saw, a router, or the like, various guide or clamping apparatuses are known to those of ordinary skill in the art. Specifically, there are two primary guides known in the prior art, assembled type and integrated type. An assembled type of guide comprises a plurality of sectional guide plates of different lengths. The user may select guide plates of different lengths and assemble them together to create the desired guide. During shipment, the guide plate may be disassembled and packaged separately to reduce the size of package and decrease shipping costs. An integrated guide apparatus is an integrated member of a fixed length, which is usually made from an extruded aluminum material which provides a very high level of precision. 
       SUMMARY OF THE INVENTION 
       [0006]    The object of the present invention is to provide an assembled type of guide rail that may be assembled and disassembled quickly. To achieve this object, the guide rail of the present invention comprises first and second guide components. Each guide component has a first end with a tongue-shaped portion extending outwardly and a second end with a groove that is fittable with the tongue-shaped portion. One of the tongue-shaped portion or the groove is formed with ribs, and the other one has slots that can connect with the ribs. The guide rail is mounted to a locking device that may fix the first and the second guide components together when the tongue-shaped portion is inserted into the groove portion. The locking device comprises a hole formed on one component and a protrusion formed on the other component. Using the fitting between the ribs and the elongate slots and the fitting of the hole and protrusion, the guide components of the guide rail in the present invention can be assembled and disassembled quickly. It also allows for easier use by the user and for more convenient packing and shipping of the guide rail. 
         [0007]    Another object of the present invention is to provide a guide rail that may achieve a fast connection between the auxiliary guide plate and the guide plate. To achieve this object, the guide rail of the present invention has an auxiliary guide component including a locating block and a main guide component including a groove that can receive the locating block. The guide rail further comprises a fixing device which can connect the auxiliary guide component to the main guide component. The locating block has a taper-tilted edge and the fixing device has a tapered surface which is fittable with the taper-tilted edge. Using the fitting between the tapered surface and the taper-tilted edge, the main guide component and the auxiliary guide component can be quickly locked together or separated from each other to quickly adjust the positional relationship between the auxiliary guide component and the main guide component during operation. 
         [0008]    A further object of the present invention is to provide a guide rail containing an angle-indicating device to quickly determine the cutting angle of the power tool mounted on the guide rail during tilted cutting. To achieve this object, the guide rail of the present invention has an auxiliary guide component including a locating block and a main guide component including a groove which can receive the locating block. The locating block also has angle-indication marks. By setting the angle-indication marks on the auxiliary guide component, the angle of the cutting edge can be quickly determined to enhance the convenience and efficiency of the operation by the user. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The present invention will be further described in detail in combination with the accompanying drawings and embodiments. 
           [0010]      FIG. 1  is an elevated view of a hand-held saw having a guide rail according to a preferred embodiment of the present invention; 
           [0011]      FIG. 2  is a top view of the guide rail of  FIG. 1 , wherein a first guide plate and a second guide plate are disassembled from each other; 
           [0012]      FIG. 3  is a top view of the guide rail of  FIG. 1 , wherein the first guide plate is connected to the second guide plate; 
           [0013]      FIG. 4  is a top view of the guide rail of  FIG. 1 , having a fixing device between an auxiliary guide plate and the first guide plate; 
           [0014]      FIG. 5  is a top view of the fixing device between the auxiliary guide plate and the first guide plate according to another embodiment of the present invention; and, 
           [0015]      FIG. 6  is a sectional cutaway view of the fixing device shown in  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION 
       [0016]      FIG. 1  shows a guide rail  10  according to a preferred embodiment of the invention, which can be used to guide a hand-held saw  20  mounted on the guide rail  10  to cut a workpiece along a straight line. In  FIG. 1 , a hand-held electrical circular saw is used as an example, however, the guide rail  10  can certainly be used together with other power tools such as electric routers, saber saws or jig saws. The hand-held electric circular saw  20  comprises a housing  21 , a circular saw blade  22  mounted at least partially within the housing  21  and a bottom plate  23  pivotally connected to the housing. The bottom plate  23  has an elongate slot  24  arranged on a lower surface. The guide rail  10  also has a protruding ridge-shaped rib  19  on an upper surface. The ridge-shaped rib  19  is adapted to fit with the elongate slot  24  so as to mount the electric circular saw  20  onto the guide rail  10 , so that the electric circular saw  20  can be moved to slide on the guide rail  10  along the ridge-shaped rib  19 . 
         [0017]    As shown in  FIGS. 2 and 3 , the guide rail  10  according to the invention is composed of a pair of elongate guide plates  11  and  12 . Since the structure of guide plate  11  is the same as that of guide plate  12 , only the structure of guide plate  11  will be described. Guide plate  11  is substantially rectangular and comprises a pair of long sides  13  and  14  and two ends  15  and  16 . End  15  has a tongue-shaped portion  17  extending outwardly, which comprises an upper tapered surface  171  and a lower tapered surface  172  which have an inclination. End  15  also has an upward rib-shaped strip  173  which is formed on the upper tapered surface, and a downward rib-shaped strip  174  which is formed on the lower tapered surface parallel to the ends  15  and  16 . Moreover, a notch  175  is formed on an outer edge of the tongue-shaped portion  17 . End  16  is formed thereon inwardly with a groove  18  that is adapted to fit with the tongue-shaped portion  17 . Groove  18  has an upper tapered surface  181  and lower tapered surface  182  which are adapted to fit with the upper tapered surface  171  and the lower tapered surface  172  of the tongue-shaped portion, respectively. Correspondingly, the tapered surfaces  181  and  182  are formed with elongate slots  183  and  184  fittable with the rib-shaped strips  173  and  174 . One of ordinary skill in the art will understand that it is also possible that the rib-shaped strips protruding from the tapered surface are formed on the tapered surfaces  181  and  182  of the groove  18 , and the elongate slots fittable with the rib-shaped strips are formed on the upper tapered surface  171  and the lower tapered surface  172  of the tongue-shaped portion. In the preferred embodiment, guide plates  11  and  12  are assembled together by inserting the tongue-shaped portion  17  of guide plate  11  into the groove  18  of guide plate  12 , or inserting the tongue-shaped portion  17  of guide plate  12  into the groove  18  of guide plate  11 . A locking device  30  is further arranged on each of the guide plates  11  and  12  for fixedly connecting the assembled guide plates  11  and  12  together. In the preferred embodiment, the locking device  30  is assembled on the guide plate near the groove  18  and comprises a switch  31 , a spring  32  and a tapered pin  33 , wherein the tapered pin  33  is fittable with the notch  175  of the tongue-shaped portion  17  and the elastic force of the spring  32  pushes the tapered pin  33  to move toward the notch  175 . When assembling, the elastic force of the spring  32  is overcome and the switch  31  is pushed backwardly, so the tapered pin  33  is moved opposite to the notch  175 . After the tapered pin  33  is completely moved out of the notch  175 , the tongue-shaped portion  17  of guide plate  11  is inserted into the groove  18  of guide plate  12  and then the switch  31  is released so that the tapered pin  33  moves into the notch  175  under the elastic force of the spring  32  to lock the guide plates  11  and  12  together. Certainly, one of ordinary skill in the art could also easily appreciate that the assembling and locking between the guide plates  11  and  12  can be achieved by a fitting between a protrusion and a hole wherein the hole is formed on the tongue-shaped portion  17  of one of the guide plates and the protrusion protruding from the tapered surface of the groove is formed in the groove  18  of the other guide plate. Furthermore, the assembling and locking between the guide plates can also be achieved by arranging a protrusion protruding from the tapered surface on the tongue-shaped portion  17  of one guide plate and arranging a hole in the groove  18  of the other guide plate. 
         [0018]    Referring to  FIGS. 2 and 4 , the guide rail  10  of the current invention further comprises an auxiliary guide plate  41  which is connectable with guide plates  11  and  12 , and whose position relative to the guide plates  11  and  12  is adjustable. Since the connection methods between the auxiliary guide plate  41  and the guide plates  11  and  12  are the same, only guide plate  11  will be explained in detail. The side  14  of guide plate  11  has a plurality of long grooves  141 . One side of the auxiliary guide plate  41  includes a plurality of locating blocks  43  that may be inserted into and connected to the long groove  141 . Each locating block  43  includes a taper-tilted edge  431 . The guide plate  11  is also mounted with a plurality of fixing devices  50  at the position corresponding to the long grooves  141 , which may fixedly connect the auxiliary guide plate  41  to the guide plate  11 . The fixing device  50  is a slidable block having a tapered surface  51  which is fittable with the taper-tilted edge  431 . By moving the slidable block  50  towards the locating block  43 , the tapered surface  51  of the slidable block  50  engages the taper-tilted edge  431  of the locating block  43 , so that locking between the auxiliary guide plate  41  and the guide plate  11  may be achieved. Correspondingly, by moving the slidable block  50  in the opposite direction, the tapered surface  51  of the slidable block  50  will be separated from the taper-tilted edge  431  of the locating block  43 , so that the auxiliary guide plate  41  will be released from the guide plate  11 . The user can easily adjust the position of the auxiliary guide plate  41  relative to the guide plates  11  and  12  and can quickly lock the saw in a selected position. 
         [0019]      FIGS. 5 and 6  illustrate another embodiment of the fixing device between the guide plate  11  and the auxiliary guide plate  41 . The fixing device  60  comprises a locating component  61  and a locking component  62  mounted on the guide plate  11 . The locating component  61  includes a steel ball  611  and a spring  612 , wherein the locking component  62  is a switch containing a tapered pin  621  on its front end. A locating block  70  has two parallel sides  71  and  72  that are parallel to the ends  15  and  16  of the guide plate  11 . When the auxiliary guide plate  41  is connected to the guide plate  11 , one side  71  of the locating block is closely adjacent to the locating component  61  and the other side  72  is closely adjacent to the locking component  62 . Side  71  is arranged thereon with a plurality of notches  73  spaced from each other with a certain pitch. Side  72  is arranged thereon with a plurality of tapered notches  74  fitted with the tapered pins  621 , and the place of each of tapered notches corresponds to each of the notches  73 . During operation, the tapered pin  621  is moved out from the tapered notch  74 , and then the auxiliary guide plate  41  is moved with respect of the guide plate  11  along a direction perpendicular to the longitudinal direction of the guide plate  11 . Steel ball  611  will be pressed into the corresponding notch  73  under the elastic force of the spring  612 . After the steel ball  611  is pressed into the notch  73  corresponding to the desired position, switch  62  will be pushed so that the tapered pin  621  will be moved into the tapered notch  74  under the driving of the switch, so as to achieve the connection between the auxiliary guide plate  41  and the guide plate  11 . 
         [0020]    According to the invention, locating blocks  43  and  70  can be further arranged with scale-indication marks  75  thereon. The scale-indication marks  75  are angle-indication marks, such as 0°, 22.5° and 45°. For example, when the electric circular saw is needed for tilted cutting at 45°, the auxiliary guide plate  41  could be moved by the user relative to the guide plates  11  and  12 , so as to have the sides  14  of the guide plates  11  and  12  align with the scale-indication mark 45°. Then the auxiliary guide plate  41  may be fixed to the guide plates  11  and  12  at the corresponding position. As a result, saw blade  22  can perform the tilted cutting of 45° under the guide of the edge  76  of the auxiliary guide plate  41 . Here, the scale-indication marks are determined according to the different distances from the intersected line of the saw blade  22  and the edge  76  to the ridge-shaped rib  19  when the electric circular saw performs the tilted cutting at different angles. When the tilted cutting angle of the electric circular saw is changed, the distance from the intersected line of the saw blade  22  and the edge  76  to the ridge-shaped rib  19  will be changed accordingly. Based on the changed distance, the corresponding tilted cutting angle can be set on the locating block  70 . The positional relationship between the auxiliary guide plate and the guide plate may be adjusted according to the scale-indication mark  75 , so as to implement the quick locating of the tilted cutting at a certain angle. 
         [0021]    The above-mentioned embodiments only describe the conception and the principle of the present invention without limitation to the contents of the invention. One skilled in the art could realize that the present invention has additional equivalent embodiments and obvious modifications which are still included in the scope of the present invention defined by the appended claims.