Patent Publication Number: US-2013247737-A1

Title: Cutting indicator for circular saw

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
     This application claims, under 35 U.S.C. § 119, priority to Taiwanese Application No. 101110400, filed Mar. 26, 2012, which application is hereby incorporated by reference in its entirety, inclusive of the specification, claims, and drawings. 
     FIELD OF THE INVENTION 
     The present disclosure relates to circular saws and more particularly, to a cutting indicator for circular saw. 
     BACKGROUND 
     Before operating a circular saw to cut a workpiece, the user can mark a cutting line on the workpiece, and then lower the circular saw blade to touch the workpiece for visually checking the alignment. After the alignment has been checked, the circular saw is operated to cut the workpiece along the marked cutting line. However, only a small part of the circular saw blade can be aimed at the marked cutting line during alignment between the circular saw blade and the marked cutting line due to the limitation of the shape of the circular saw blade, and thus an error can easily occur, resulting in an inaccurate cutting size. Therefore, regular circular saws are commonly equipped with a cutting indicator that can be controlled to emit a laser beam, forming a laser indicating line on the surface of the workpiece. Subject to the indication of the laser indicating line, the circular saw blade can be operated to cut the workpiece accurately. 
     However, prior to the workpiece cutting operation, the user normally needs to make a 3-dimensional adjustment to the cutting indicator. To accomplish this, the user first needs to adjust the laser beam projection angle, and then keep the laser indicating line formed by the laser beam parallel to the workpiece cutting line. Finally, the user must move the laser indicating line into alignment with the workpiece cutting line. After these three adjustment steps are accurately done, the user can then start operating the circular saw to cut the workpiece. 
     For example, China Patent Publication No. CN201058385 discloses a circular saw, entitled “Saw Cutting Machine”, which teaches a first step of rotating a screw nail  35 S to assure parallel alignment between the plane beam LP and the circular saw blade  23 , a second step of rotating a screw nail  38 S to assure parallel alignment between the line of light LPL and the circular saw blade  23 , and a third step of rotating a screw nail  34  to assure positioning of the circular saw blade  23  within the width of the plane beam LP, or to enable the plane beam LP to be positioned adjacent to one side of the circular saw blade  23 . In these aforementioned techniques, the lens for converting the emitted laser beam to a plane beam is directly mounted in the laser module. When an adjustment of the laser indicating line is necessary, the user must use a tool to rotate the screw nails  35 S,  38 S,  34 , respectively. These techniques also have the drawback of a low adjustment speed. Further, adjustment in each dimension may affect one another due to the constraint of the design of the laser module itself, resulting in user confusion about the cognitive dimensions. This adjustment method likely causes considerable trouble and inconvenience for unfamiliar users since user skills also determine the effects on the adjustment. 
     SUMMARY 
     The present disclosure has been accomplished under the circumstances in view. It is the main object of the present disclosure to provide a cutting indicator for a circular saw, which facilitates simple and quick adjustment. 
     To achieve this and other objects of the present disclosure, a cutting indicator comprises an adjusting base, a lens, and a laser generator. The adjusting base is pivotally mounted to a saw arm of a circular saw by a pivot bolt, defining a through hole therein. The lens is mounted at the saw arm corresponding to the adjusting base. The laser generator is mounted in the through hole of the adjusting base, and adapted to generate a laser beam. Thus, when the laser beam generated by the laser generator passes the lens, it is converted to a plane beam, thereby forming a laser indicating line on the workpiece to be cut. 
     Biasing the adjusting base relative to the saw arm allows the plane beam to be quickly switched between a predetermined first plane position and a predetermined second plane position that are substantially aligned parallel to two opposing lateral planes of the circular saw blade of the circular saw. Thus, quick adjustment of the laser indicating line can be easily achieved. 
     Preferably, the cutting indicator further comprises a rotary knob rotatably mounted in the adjusting base and connected with the laser generator for adjusting the laser beam projection angle. 
     Further, the lens can be adjustably mounted in the saw arm for obtaining the optimal plane beam. Alternatively, the lens can be affixed to the saw arm after calibration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
       These and other features, aspects, and advantages of the present disclosure will become better understood with regard to the following description, appended claims, and accompanying drawings. 
         FIG. 1  is a side plan view of a circular saw equipped with a cutting indicator in accordance with the present disclosure. 
         FIG. 2  is an exploded view of the cutting indicator in accordance with the present disclosure. 
         FIG. 3  is a side plan view of the circular saw of  FIG. 1 , illustrating a status of use of the cutting indicator. 
         FIG. 4  is a schematic sectional view of the adjusting base of the present disclosure, illustrating the condition of the rotary knob before being rotated. 
         FIG. 5  is a schematic sectional view according to  FIG. 4 , illustrating the rotary knob after being rotated. 
         FIG. 6  is a schematic top plan view of the present disclosure, illustrating a first relationship between the plane beam and the two lateral planes of the circular saw blade. 
         FIG. 7  is a schematic top plan view of the present disclosure, illustrating a second relationship between the plane beam and the two lateral planes of the circular saw blade. 
         FIGS. 8A and 8B  illustrate the relative positions among the two lateral planes of the circular saw blade, the workpiece and the plane beam based on different predetermined plane positions. 
         FIGS. 9A and 9B  illustrate the relative positions among the two lateral planes of the circular saw blade, the workpiece and the plane beam based on different predetermined plane positions. 
     
    
    
     It should be noted that the drawing figures are not necessarily drawn to scale, but instead are drawn to provide a better understanding of the components thereof, and are not intended to be limiting in scope, but rather to provide exemplary illustrations. It should further be noted that the figures illustrate exemplary embodiments of a cutting indicator for a circular saw and the components thereof, and in no way limit the structures or configurations of a cutting indicator for a circular saw and components thereof according to the present disclosure. 
     DETAILED DESCRIPTION  
     Other and further advantages and features of the present disclosure will be understood by reference to the following specification in conjunction with the accompanying drawings. 
     While the disclosure is susceptible to various modifications and alternative constructions, certain illustrative embodiments are shown in the drawings and are described in detail below. It should be understood, however, that there is no intention to limit the disclosure to the specific embodiments disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, combinations, and equivalents falling within the spirit and scope of the disclosure. 
     It will be understood that, unless a term is expressly defined in this disclosure to possess a described meaning, there is no intent to limit the meaning of such term, either expressly or indirectly, beyond its plain or ordinary meaning 
     Referring to  FIG. 1 , a cutting indicator  30  is shown used in a circular saw  10 , which comprises a worktable  12 , a saw arm  14 , and a circular saw blade  16 . The saw arm  14  comprises a support base  141 , and a circular saw blade holder  142 . The support base  141  is mounted at the worktable  12 , and the circular saw blade holder  142  is pivotally coupled to the support base  141 . The circular saw blade  16  is rotatably supported on the saw arm  14 , and movable with the saw arm  14  to cut a workpiece  20 , as shown in  FIG. 3 . The circular saw blade  16  is substantially circular in shape, defining a thickness W and two opposing lateral planes LP 1 , RP 1 , as shown in  FIGS. 8 and 9 . 
     Referring to  FIG. 2 , the cutting indicator  30  comprises an adjusting base  40 , two locating members  50 , a lens  60 , a laser generator  70 , and a rotary knob  80 . 
     The adjusting base  40  is pivotally connected to the circular saw blade holder  142  of the saw arm  14  by a pivot member, such as a pivot bolt  42 . The adjusting base  40  also comprises a through hole  44  cut through opposing top and bottom walls thereof, and a constraint portion  45  radially formed in the through hole  44 , as shown in  FIGS. 4 and 5 . Two longitudinal holes, such as screw holes  46 , are respectively and transversely disposed at two opposite lateral sides of the adjusting base relative to the through hole  44 . It is to be noted that the adjusting base  40  can be pivotally mounted at the support base  141  of the saw arm  14  subject to fit actual needs. 
     In this embodiment, the two locating members  50  are screw rods  50   a,    50   b  respectively threaded into the screw holes  46  of the adjusting base  40 . As shown in  FIGS. 6 and 7 , at least one of the two screw rods  50   a,    50   b  is arranged to provide a stop against one respective stop wall  143  of the circular saw blade holder  142  to hold the adjusting base  40  in position. It should be understood that positioning of the adjusting base  40  can be achieved by a relative structural design between the adjusting base  40  and the circular saw blade holder  142  instead of the use of the two screw rods  50   a ,  50   b.    
     The lens  60  in this embodiment may be a wave lens or a serrated lens adjustably mounted in the circular saw blade holder  142  of the saw arm  14 , and corresponds to the through hole  44  of the adjusting base  40 . The through hole  44  is further adapted to adjust a better planar light beam. Alternatively, the lens  60  can be positioned in the saw arm  14  after calibration, or made in a detachable form to facilitate cleaning and replacement. 
     The laser generator  70  is mounted in the through hole  44  of the adjusting base  40  and inserted with the bottom end thereof into the constraint portion  45  of the through hole  44 . The laser generator  70  is controllable to generate a laser beam in this position. When a laser beam generated by the laser generator  70  passes through the lens  60 , the laser beam is converted to a laser plane and projected onto the worktable  12  or the workpiece  20 , forming a laser indicating line L, as shown in  FIG. 3 . 
     Referring back to  FIGS. 4 and 5 , the rotary knob  80  comprises an operating head  81  having a thin cylindrical shape rotatably supported on the top wall of the adjusting base  40 , and a wire hole  82  cut through opposing top and bottom sides of the operating head  81  for the passing of top power wires of the laser generator  70 . A cylindrical receptacle  83  having a varying wall thickness  85  downwardly extends from the bottom side of the operating head  81  and inserts into the through hole  44  of the adjusting base  40 . An accommodation hole  84  is eccentrically formed in the cylindrical receptacle  83  in concentric relationship with the wire hole  82  and is surrounded by the varying wall thickness  85 . The accommodation hole  84  is further adapted to accommodate the upper end of the laser generator  70 . Thus, adjustment of the laser beam projection angle can be achieved by rotating the operating head  81  of the rotary knob  80  to cause the laser generator  70  to be tilted by the varying wall thickness  85  of the cylindrical receptacle  83  such that the constraint portion  45  in the through hole  44  of the adjusting base  40  provides a stop against the laser generator  70 , as shown in  FIG. 5 . 
     During adjustment, rotating the rotary knob  80  tilts the laser generator  70  due to the eccentric coupling between the laser generator  70  and the rotary knob  80 , thereby changing the laser beam projecting angle to the extent where the plane beam P formed by diffusion of the laser beam passed through the lens  60  is aligned parallel to the two lateral planes LP 1 , RP 1  of the circular saw blade  16 . At this time, the laser indicating line L formed on the workpiece  20  by the plane beam P is kept in parallel to the cutting line made on the workpiece  20  by the circular saw blade  16 . It should be appreciated that if the projection angle of the laser generator  70  is affixed during installation and not allowed for adjustment by the user, then the aforementioned step of rotating the rotary knob, or even the rotary knob  80  itself, can be eliminated. 
     Thereafter, turning the adjusting base  40  about the pivot bolt  42  enables the plane beam P to be moved in a parallel manner relative to the circular saw blade  16 . Thus, the user can adjust the plane beam P to a substantially parallel position relative to the two lateral planes LP 1 , RP 1  of the circular saw blade  16  subject to the thickness of the circular saw blade  16  or other actual needs, as shown in  FIGS. 6 and 7 . After the position of the plane beam P is assured, a corresponding locating member  50   a,    50   b  is fastened subject to the pivoting direction of the adjusting base  40 , thereby controlling the angle of the adjusting base  40 . For example, if the adjusting base  40  is biased to the right, the right-sided locating member  50   a  will be stopped against the circular saw blade holder  142 , and the left-sided locating member  50   b  will be spaced from the respective stop wall  143  of the circular saw blade holder  142 , as shown in  FIG. 6 . At this time, the plane beam P will be formed on the right side relative to the circular saw blade  16 . On the contrary, if the adjusting base  40  is biased to the left, the plane beam P will be formed on the left side relative to the circular saw blade  16 , as shown in  FIG. 7 . 
     After the position of the adjusting base  40  is set, the user can selectively and rapidly switch between a predetermined first plane position P 1  and a predetermined second plane position P 2  that are substantially aligned parallel to the two lateral planes LP 1 , RP 1  of the circular saw blade  16 . In this embodiment, the first plane position P 1  and the second plane position P 2  are respectively disposed at an outer side relative to the lateral planes LP 1 , RP 1  of the circular saw blade  16 , as shown in  FIGS. 8A and 8B , or at an inner side relative to the lateral planes LP 1 , RP 1  of the circular saw blade  16 , as shown in  FIGS. 9A and 9B . After adjustment of the laser indicating line L, the user may start operating the circular saw  10  to cut the workpiece  20 . 
     As stated above, adjusting the position of the plane beam P of the cutting indicator  30  does not need any tools. Simply moving the adjusting base  40  can achieve quick adjustment. Thus, the present invention advantageously simplifies the plane beam adjustment process, thus enhancing convenience for the user. 
     Although a particular embodiment of the disclosure has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the disclosure. Accordingly, the disclosure is not to be limited except as by the appended claims.