Abstract:
A cutting line indicator is adapted to be installed on a circular sawing blade of a sawing machine to produce a line-shaped beam to delineate the cutting line of the circular sawing blade. The cutting line indicator has a light source for generating a light beam that forms the line-shaped beam, a lower cover that is made from a first metal plate, and a spindle received in the lower cover, with the spindle being made from a second metal plate. An inner housing is arranged on the lower cover, with the light source coupled to the inner housing. An upper cover is coupled to enclose the lower cover.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a cutting line indicator, and in particular, to a cutting line indicator which can be manufactured with metal plates.  
         [0003]     2. Description of the Prior Art  
         [0004]     It is a common practice when cutting wood, for example, with a sawing machine, that the operator is required to lower the operation arm of the sawing machine to align the cutting line. This is because the operator cannot identify the actual cutting position of the circular sawing blade of a sawing machine, and is lowering the operation arm to avoid a large error which would result in a waste of materials or a poor-quality cut. The operation described above (lowering the operation arm) is not only inconvenient, but also fails to meet the demands of modern technology.  
         [0005]     It has been suggested to provide cutting line indicators with laser beams or other light sources that function to delineate the cutting line of a circular sawing blade, so as to save operation time and to enhance the quality of the cut. Examples of such devices are illustrated in U.S. Pat. No. 5,862,727 (“Laser Arbor”), U.S. Pat. No. 6,035,757 (“Circular Saw Cut Alignment Device”), and U.S. Pat. No. 6,755,107 (“Miter Saw Having a Light Beam Alignment System”), which disclose cutting line indicators equipped on the spindle of a circular sawing blade. When the sawing blade rotates, the indicator can generate a line-shaped laser beam to delineate the cutting line.  
         [0006]     Unfortunately, these conventional cutting line indicators suffer from a number of drawbacks. For example, these cutting line indicators have a complicated structure and provide insufficient functions. In addition, most of these conventional cutting line indicators have components (e.g., housing) that are produced using a lost-wax casting process because they are subjected to torsion as a result of being secured on the spindle of a circular sawing blade. In this regard, the lost-wax casting process and a stamping process are different processes that can be used to manufacture products that are made of metals. Production using the lost-wax casting process is more expensive than production using a stamping process because the lost-wax casting process is more complex and cannot be accomplished using automation. Thus, the production cost for these conventional cutting line indicators is high, and they are not conducive to mass production. In addition, sand holes of the semi-finished products of a lost-wax process are so large that the failure rate of electroplating is higher than for other products.  
       SUMMARY OF THE DISCLOSURE  
       [0007]     It is an object of the present invention to provide a cutting line indicator having some parts (i.e., the parts that are subjected to torsion) manufactured with metal plates to avoid the use of the lost-wax casting process.  
         [0008]     It is another object of the present invention to provide a cutting line indicator having a recess that is provided to accommodate a laser module for generating a laser beam. The recess has at least one rib to allow for adjustment of the inclination of the laser beam.  
         [0009]     In order to accomplish the objects of the present invention, there is provided a cutting line indicator that is adapted to be installed on a circular sawing blade of a sawing machine to produce a line-shaped beam to delineate the cutting line of the circular sawing blade. The cutting line indicator has a light source for generating a light beam that forms the line-shaped beam, a lower cover that is made from a first metal plate, and a spindle received in the lower cover, with the spindle being made from a second metal plate. An inner housing is arranged on the lower cover, with the light source coupled to the inner housing. An upper cover is coupled to enclose the lower cover.  
         [0010]     In an alternative embodiment of the present invention, the inner housing is provided with a recess to accommodate the light source, the recess having at least a rib for adjusting the inclination of the light source with respect to the lower cover. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is a perspective view of a cutting line indicator in accordance with one embodiment of the present invention.  
         [0012]      FIG. 2  is an exploded perspective view of the cutting line indicator of  FIG. 1 .  
         [0013]      FIG. 3  is an exploded perspective view of the rhomboid lens of the cutting line indicator of  FIG. 1 .  
         [0014]      FIG. 4  is an exploded perspective view of the laser module of the cutting line indicator of  FIG. 1 .  
         [0015]      FIG. 5  is a front plan view illustrating the cutting line indicator of  FIG. 1  in use with a conventional miter saw.  
         [0016]      FIG. 6  is a exploded perspective view illustrating a bracket for use in securing the cutting line indicator of  FIG. 1  on a spindle of a sawing machine.  
         [0017]      FIG. 7  is a block diagram of an IR transmitting circuit and an IR receiving circuit that can be used to operate the cutting line indicator of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]     The following detailed description is of the best presently contemplated modes of carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating general principles of embodiments of the invention. The scope of the invention is best defined by the appended claims.  
         [0019]      FIGS. 1-4  illustrate a cutting line indicator  100  in accordance with one embodiment of the present invention. Referring first to  FIG. 5 , the cutting line indicator  100  is secured on the spindle  200  of the circular sawing blade  202  of a sawing machine  204  (e.g., a miter saw) by a screw  240  (see  FIG. 6 ) after the spindle  200  is inserted into a center hole  190  (see  FIG. 1 ) when the cutting line indicator  100  is operated. Consequently, a light beam  206  is generated through a light exit window  117  (see  FIG. 1 ), with the beam  206  capable of delineating the cutting line of the circular sawing blade  202 .  
         [0020]     Referring to  FIGS. 1 and 2 , the cutting line indicator  100  includes a lower cover  110 , a spindle  120 , an inner housing  130 , and an upper cover  140 . The lower cover  110  and the upper cover  140  form the overall housing for the cutting line indicator  100  and define the center hole  190 , with the components of the cutting line indicator  100  retained therein. The spindle  120  is secured on the lower cover  110  by screws  121  and  122  which are inserted through holes  111  and  112 , respectively, in the lower cover  110 . The inner housing  130  is also secured on the lower cover  110  by screws  131  and  132  which are inserted through holes  133  and  134 , respectively, in the inner housing  130  and then screwed into screw holes  113  and  114 , respectively, in the lower cover  110 . The upper cover  140  is secured on the lower cover  110  by screws  141  and  142  which are inserted through holes  115  and  116 , respectively, in the lower cover  110  and holes  135  and  136 , respectively, in the inner housing  130 .  
         [0021]     The lower cover  110  and the spindle  120  are subjected to torsion resulting from a screw which is used to secure the cutting line indicator  100  on a circular sawing blade. In order to (i) withstand the torsion resulting from the securing force, (ii) minimize production cost, and (iii) facilitate mass production, the lower cover  110  and the spindle  120  are both made from a metal plate that is formed by a stamping process. Specifically, the lower cover  110  is manufactured with a first metal plate (e.g., a galvanized iron sheet) by a stamping process and the spindle  120  is manufactured with a second metal plate (e.g., a galvanized iron sheet) by a stamping process that can be the same as the stamping process for the first metal plate. For example, the first and second metal plates can be a galvanized iron sheet, and the thickness of the second metal plate is preferably larger than that of the first metal plate. By providing both the lower cover  110  and the spindle  120  in the form of a metal plate that is formed by a stamping process, the present invention avoids the use of the lost-wax casting process, thereby allowing the manufacture to be automated so as to reduce the costs.  
         [0022]     Furthermore, since the inner housing  130  and the upper cover  140  are not subjected to torsion, they do not need to be made of metal, and instead can be made with plastics and manufactured using a mold injection process. Referring also to  FIG. 3 , the inner housing  130  is also provided with a structure to accommodate a laser module  150  (acting as a light source), batteries  160 , a centrifugal switch  170 , and a rhomboid lens  180  that together function to produce a line-shaped beam  206 .  
         [0023]     The batteries  160  provide the power for the laser module  150  to generate a laser beam. The centrifugal switch  170  is electrically connected to the batteries  160  whose power can be conducted through the laser module  150  as the circular sawing blade  202  rotates and in turn actuates the rotation of the cutting line indicator  100 , with the supply of power from the batteries  160  being cut off when the circular sawing blade  202  stops rotating. The rhomboid lens  180  is secured in a recess  183  (as shown in  FIG. 3 ) in the inner housing  130  by a screw  181  and a fixing plate  182 . The rhomboid lens  180  changes the advancing direction of the laser beam generated by the laser module  150 , rendering the laser beam generated from the laser module  150  closer to the circular sawing blade  202 .  
         [0024]     Referring to  FIG. 4 , the inner housing  130  is provided with a recess  151  to accommodate the laser module  150 . The recess  151  is provided with at least one rib  152  that acts as a pivot for adjusting the inclination of the laser module  150 . Additional ribs similar to rib  152  can also be provided in the recess  151 . Adjusting the inclination of the laser module  150  will in turn adjust the laser beam generated by the laser module  150  to correctly point to the cutting line of a circular sawing blade  202  (i.e., the contacting edge between a circular sawing blade  202  and a work piece). As shown in  FIG. 4 , the laser module  150  is first secured in the recess  151  by screws  153  and  154  that extend through an arcuate fixing plate  155 , with the fixing plate  155  acting to cover and secure the laser module  150 . Then, the laser module  150  can be made to tilt in opposite directions by adjusting the screws  156  and  157 . Consequently, the laser beam generated by the laser module  150  can be directed to the desired cutting line of a circular sawing blade  202 .  
         [0025]     Referring to  FIG. 6 , a bracket  230  can be positioned around the spindle  200  of the sawing machine  204  to fit the center hole  190  of the cutting line indicator  100  when the size of the spindle  200  is smaller then the size of the center hole  190 . The screw  240  is inserted through the center hole  190  and then screwed into the spindle  200 . Thus, by providing a set of brackets  230  that have different sizes, the cutting line indicator  100  can be secured on a variety of different sawing machines  204 .  
         [0026]     As described above, the centrifugal switch  170  is used to conduct the power of the batteries  160  through the laser module  150  as the circular sawing blade  202  rotates, thereby actuating the rotation of the cutting line indicator  100 . As an alternative, the centrifugal switch  170  can be replaced with an infra-red (IR) transmitting circuit  210  and an IR receiving circuit  220  as shown in  FIG. 7 . The IR transmitting circuit  210  includes a battery  211 , a switch  213 , an IR driver  215  and an IR LED (Light Emitting Diode)  217 . The IR LED  217  emits infrared light when the switch  213  is turned oh and the power of the battery  211  is supplied to the IR driver  215 . The IR receiving circuit  220  includes an IR receiver  221 , a peak value detector  223  and a laser driver  225 . The peak value detector  223  detects a peak value of the infrared light received by the IR receiver  221 , converts the received infrared light into a voltage signal, and then transmits the voltage signal to the laser driver  225  to drive the laser module  150  for emitting the laser beam.  
         [0027]     Referring to  FIG. 5 , the IR transmitting circuit  210  can be attached to a protection cover  208  for the sawing machine  204 , and the IR receiving circuit  220  can be secured inside the cutting line indicator  100 . The user can turn on the switch  213  for emitting infrared light when the user desires to operate the sawing machine  204 , and then the laser beam is emitted for forming the line-shaped beam  206  after the IR receiver  221  receives the infrared light. Otherwise, the user can turn off the switch  213  if the user wants to stop the operation of the sawing machine  204 .  
         [0028]     While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention.