Abstract:
A quick release structure for use in the saw blade guard assembly of a table saw is disclosed to include a mounting member affixed to the base of the table saw, a coupling block detachably attached to the mounting member to hold a pivoted attachment member, for example, a saw blade guard, and a rotary locking member mounted in the coupling block and rotatable relative the coupling block between two positions to lock the coupling block to the mounting member or to release the coupling block.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to a table saw and more particularly, to the saw blade guard assembly of a table saw that uses a quick release structure. 
   2. Description of the Related Art 
     FIG. 1  shows a saw blade guard assembly  1  for table saw according to the prior art. According to this design, the saw blade guard assembly  1  comprises a riving knife  2 , a guard  3 , two detents  4 , and a spring member  5 . The riving knife  2  is affixed to the base of the table saw and kept apart from the saw blade (not shown) at a distance to avoid jamming of already cut and separated parts of the workpiece, for example wood, during cutting. The riving knife  2  has two pivot holes  2   a  and  2   b  and an axle hole  2   c  at the top. The guard  3  is pivotally connected to the pivot hole  2   a  at the rear end of the riving knife  2  with a pin  3   a . The two detents  4  are pivotally bilaterally connected to the pivot hole  2   b  at the front end of the riving knife  2  with a pin  4   a  and two rings  4   b . The detents  4  are to prohibit jumping of the cut part during cutting. The spring member  5  is mounted on the rings  4   b , having two opposite ends respectively hooked on the two detents  4  to impart a forward biasing force to the detents  4 , causing the detents  4  to rest the respective front ends on the pin  4   c  that is inserted through the axle hole  2   c  so that the detents  4  are kept pressed on the surface of the workpiece to prohibit jumping of the cut part during cutting. 
   The aforesaid structure provides a protection for safety operation of the table saw. However, because the guard  3  and the detents  4  are fastened to the riving knife  2  with pins  3   a  and  4   a , it is complicated to dismount the parts for package to save the packing dimensions during delivery of the machine. Further, dismounting the guard  3  and the detents  4  requires a special tool. After dismounting, the detached parts (such as the pins) must be well received to prevent the parts from missing. It is also complicated to assemble the parts again. 
   SUMMARY OF THE INVENTION 
   The present invention has been accomplished under the circumstances in view. It is therefore one objective of the present invention to provide a quick release structure, which allows quick mounting and dismounting of the parts equipped with the quick release structure, thereby saving much mounting and dismounting time. 
   It is another objective of the present invention to provide a saw blade guard assembly for table saw, which uses the aforesaid quick release structure so that the saw blade guard assembly can quickly be removed from the table saw or installed in the table saw without using tools. 
   To achieve the aforesaid objectives, the quick release structure comprises a mounting member having a body with a retaining hole, a coupling block having a clamping groove for fastening to the body of the mounting member and a through hole in communication with the clamping groove, and a rotary locking member having a rod body pivotally inserted in the through hole of the coupling block and provided with a retaining portion at an end thereof engaging the retaining hole of the mounting member, and a pushable portion at the other end thereof turnable by an external force to move the retaining portion to be disengaged from the retaining hole of the mounting member. 
   Further, the saw blade guard assembly in accordance with the present invention has an attachment member using the quick release structure so that the attachment member can quickly be installed in the table saw or dismounted from the table saw. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
       FIG. 1  is an exploded view of a saw blade guard assembly for table saw according to the prior art; 
       FIG. 2  is an exploded view of a saw blade guard assembly for table saw according to a first embodiment of the present invention; 
       FIG. 3  is similar to  FIG. 2  but showing some parts of the saw blade guard assembly are assembled; 
       FIG. 4  is a perspective view of the first coupling block according to the first embodiment of the present invention; 
       FIG. 5  corresponds to  FIG. 4  when viewed from another direction; 
       FIG. 6  is a sectional view taken along line  6 - 6  of  FIG. 4 ; 
       FIG. 7  is a sectional view taken along line  7 - 7  of  FIG. 4 ; 
       FIG. 8  is a perspective view of the second coupling block according to the first embodiment of the present invention; 
       FIG. 9  is a perspective view of the retaining rod according to the first embodiment of the present invention; 
       FIG. 10  is a perspective view of the first embodiment of the present invention, showing that the lug is held in the first position and the first coupling block is locked to the mounting member; 
       FIG. 11  is a sectional view in an enlarged scale of a part of  FIG. 10 , showing the positioning of the rotary locking member in the first coupling block; 
       FIG. 12  is a front view of  FIG. 11 ; 
       FIG. 13  is similar to  FIG. 10  but showing that the lug is turned to the second position and the first coupling block is released from the mounting member; 
       FIG. 14  is a sectional view in an enlarged scale of a part of  FIG. 13 , showing the positioning of the rotary locking member in the first coupling block; 
       FIG. 15  is a front view of  FIG. 14 ; 
       FIG. 16  is a perspective view of a part of the first embodiment of the present invention, showing that the lug is held in the first position and the second coupling block is locked to the mounting member; 
       FIG. 17  is similar to  FIG. 16  but showing that the lug is turned to the second position and the second coupling block is released from the mounting member; 
       FIG. 18  is a perspective view of a second embodiment of the present invention; 
       FIG. 19  is a schematic perspective assembly view of the second embodiment of the present invention, showing that the lug is held in the first position and the coupling block is locked to the mounting member, and 
       FIG. 20  is similar to  FIG. 19  but showing that the lug is turned to the second position and the coupling block is released from the mounting member. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   As shown in  FIGS. 2-17 , a saw blade guard assembly  100  in accordance with a first embodiment of the present invention comprises a mounting member  10 , a first coupling block  20 , a second coupling block  30 , two rotary locking members  40 , a return member  46 , a guard  50 , two detents  60 , and a biasing member  62 . The mounting member  10 , the coupling blocks  20  and  30 , the rotary locking members  40  and the return member  46  constitute a quick release structure. 
   The mounting member  10  has a body  12 . The body  12  is inserted with its bottom end into the inside of the base of the table saw (not shown), having two retaining holes  14  near the top, two top notches  16  respectively formed on the topmost edge above and in communication with the retaining holes  14 , and two hook portions  18  respectively suspending in between the retaining holes  14  and the top notches  16 . 
   The first coupling block  20  has a top surface  201 , a bottom surface  202 , a clamping groove  21  formed on the bottom surface  202  for securing the body  12  of the mounting member  10 , a through hole  22  cut through the top surface  201  and the bottom surface  202  in communication with the clamping groove  21 , a first stop block  23  and a second stop block  24  upwardly protruding from the top surface  201  and defining a first stop portion and a second stop portion respectively, and a countersunk groove  25  formed on the top surface  201  in communication with the through hole  22 . The through hole  22  is a stepped hole having an upper section  221  of relatively smaller diameter and a lower section  222  of relatively greater diameter. Further, an axle sleeve  26  is transversely fastened to the first coupling block  20  near its rear end (see  FIG. 2 ) to work as a mounting portion of the first coupling block  20 . A pivot pin  52  is fastened to the axle sleeve  26  to pivotally connect one end of a link  51  to the first coupling block  20 . The other end of the link  51  is pivotally connected to an attachment member, i.e. the guard  50 . 
   The second coupling block  30  is substantially similar to the first coupling block  20 . As shown in  FIG. 8 , the second coupling block  30  has a clamping groove  31 , a through hole  32 , a first stop block  33 , a second stop block  34 , a countersunk groove  35 , and an axle sleeve  36 . The second coupling block  30  further has two protruding rods  37  respectively extended from two opposite lateral sides. 
   The two rotary locking members  40  are identical and respectively inserted through the through hole  22  of the first coupling block  20  and the through hole  32  of the second coupling block  30 , each including a retaining rod  41  and a lug  44 . The arrangement between one rotary locking member  40  and the first coupling block  20  is explained hereinafter. Because the arrangement between the other rotary locking member  40  and the second coupling block  20  is similar to the arrangement between one rotary locking member  40  and the first coupling block  20 , no further detailed description in this regard is necessary. 
   The retaining rod  41  has a rod body  42 , which has an outer diameter approximately equal to the upper section  221  of the through hole  22  of the first coupling block  20  and is inserted into the upper section  221  of the through hole  22  of the first coupling block  20 , and a protrusion head  43  disposed at the bottom end of the rod body  42  and suspending in the lower section  222  of the through hole  22  of the first coupling block  20 . The protrusion head  43  works as the retaining portion of the rotary locking member  40 . 
   The lug  44  works as the pushable portion of the rotary locking member  40 . The lug  44  is affixed to the rod body  42  of the retaining rod  41  with a pin  45 , having a rod  441  for turning by the user. The return member  46  according to this embodiment is a torsion spring mounted in the countersunk groove  25  of the first coupling block  20  and adapted to impart a return force to the lug  44  each time the lug  44  is biased by an external force. When the lug  44  receives no external pressure, the rod  441  is stopped at the first stop block  23  in a first position P 1 , as shown in  FIGS. 10-12 . At this time, the protrusion head  43  is engaged with one hook portion  18  of the mounting member  10  (see  FIG. 11 ), thus the first coupling block  20  is not detachable from the mounting member  10 . On the contrary, when giving a pressure to the rod  441  against the aforesaid return force, the lug  44  is moved from the first position P 1 , as shown in  FIG. 10 , to a second position P 2  and stopped at the second stop block  24 , as shown in  FIGS. 13-15 . At this time, the protrusion head  43  is disposed in a crossed manner relative to the body  12  of the mounting member  10  (see  FIG. 15 ) and disengaged from the corresponding hook portion  18  of the mounting member  10  (see  FIG. 14 ), allowing removal of the first coupling block  20  with the guard  50  from the mounting member  10 . Therefore, the invention allows quick dismounting of the guard from the table saw. 
   The two detents  60  are respectively pivotally connected to the two opposite ends of the axle sleeve  36  in the second coupling block  30  by a pin  61 . The biasing member  62  is mounted on the axle sleeve  36  and stopped against the detents  60  to force the detents  60  against the protruding rods  37  respectively. 
   As shown in  FIGS. 16 and 17 , the method of dismounting the detents  60  is similar to the way of dismounting the guard  50 , i.e., operate the rod  441  of the associating rotary locking member  40  to turn the associating lug  44  from the first position P 1  to the second position P 2 . During rotation of the lug  44 , the head  43  is moved from the position shown in  FIG. 11  to the position shown in  FIG. 14  where the protrusion head  43  is disengaged from the corresponding hook portion  18  of the mounting member  10 , allowing removal of the second coupling block  30  with the two detents  60  from the mounting member  10 . 
   On the contrary, when wanting to install the guard  50  or the detents  60  in the mounting member  10 , for example, when wanting to install the guard  50  in the mounting member  10 , operate the rod  441  to hold the lug  44  in the second position P 2 , and then move the first coupling block  20  toward the body  12  of the mounting member  10 . When moving the first coupling block  20  toward the body  12  of the mounting member  10 , the protrusion head  43  is intersected with the body  12  at right angles (see  FIGS. 14 and 15 ), and therefore the protrusion head  43  of the associating rotary locking member  40  is moved through the associating top notch  15  into the associating retaining hole  13 . When the protrusion head  43  is inserted into the associating retaining hole  13 , release the rod  441  for enabling the return member  46  to return the lug  44  from the second position P 1  to the first position P 1 . When the lug  44  reaches the first position P 1 , the protrusion head  43  is forced into engagement with the associating hook portion  18  of the mounting member  10  again (see  FIG. 1 ), thereby finishing the installation of the guard  50 . 
     FIGS. 18-20  show a saw blade guard assembly  100 ′ in accordance with a second embodiment of the present invention. According to this embodiment, the saw blade guard assembly  100 ′ comprises a mounting member  70 , a coupling block  80 , a rotary locking member  90 , a return member  96 , two detents  110 , and a biasing member  112 . The mounting member  70 , the coupling block  80 , the rotary locking member  90  and the return member  96  constitute a quick release structure. 
   The mounting member  70  has a body  71  and a retaining hole  72  on the body  71  near its top side. 
   The coupling block  80  has a bottom clamping groove  81  for securing the body  71  of the mounting member  70 , a stepped through hole  82 , which has an upper section  821  of relatively smaller diameter and a lower section  822  of relatively greater diameter for accommodating the rotary locking member  90 , a top cover plate  83 , which constitutes the top surface of the coupling block  80  and has an arched slot  831 , an axle sleeve  84  fixedly provided near the rear side and working as a mounting portion of the coupling block  80 , two protruding rods  85  respectively extended from two opposite lateral sides near the front, and a countersunk groove  86 . 
   The rotary locking member  90  includes a retaining rod  91  and a lug  94 . The lug  94  is fixedly connected to the top end of the retaining rod  91 , forming the pushable portion of the rotary locking member. The retaining rod  91  has a rod body  92  and a protrusion head  93 . The rod body  92  has a diameter approximately equal to the upper section  821  of the through hole  82 , and is inserted through the upper section  821  of the through hole  82 . The protrusion head  93  is radially extended from the bottom end of the retaining rod  91  and suspending in the lower section  822  of the through hole  82 . The protrusion head  93  works as a retaining portion of the rotary locking member  90 . The lug  94  has a top rod  95  extending out of the arched slot  831  of the cover plate  83  for operation by the user to turn the lug  94  and the retaining rod  91  in the through hole  82 . The two ends of the arched slot  831  form a first stop portion and a second stop portion of the coupling block  80  respectively. Thus, the user can move the top rod  95  along the arched slot  831  between a first position P 1  where the rod  95  is stopped at one end of the arched slot  831  (see  FIG. 19 ) and a second position P 2  where the rod  95  is stopped at the other end of the arched slot  831  (see  FIG. 20 ). Further, a return member  96  is mounted in the countersunk groove  86  of the coupling block  80  and adapted to impart a return force to the lug  94 , biasing the lug  94  toward the first position P 1 . 
   The detents  110  are respectively pivotally connected to the two opposite ends of the axle sleeve  84  of the coupling block  80  by a pin  111 . The biasing member  112  is mounted on the axle sleeve  84 , having two opposite ends respectively hooked in a respective hook hole  110   a  on each of the detents  110 . Thus, the biasing member  112  imparts a biasing force the detents  110  against the protruding rods  85  respectively. 
   When the rod  95  receives no external force, the rod  95  is stopped at one end of the arched slot  831  in the first position P 1 . At this time, the rod body  92  of the retaining rod  91  is disposed at one side of the body  71  of the mounting member  70 , and the protrusion head  93  of the rotary locking member  90  is engaged into the retaining hole  72  (see  FIG. 19 ) to lock the coupling block  80  to the mounting member  70 . When moving the rod  95  along the arched slot  831  from the first position P 1  to the second position P 2  against the return force of the return member  96  (see  FIG. 20 ), the retaining rod  91  is rotated to disengage the protrusion head  93  from the retaining hole  72 , allowing removal of the coupling block  80  from the mounting member  70 . On the contrary, when wanting to install the coupling block  80  in the mounting member  70 , operate the rod  95  to hold the lug  94  in the second position P 2 , and then attach the clamping groove  81  of the coupling block  80  to the topmost edge of the body  71  of the mounting member  70 , and then release the rod  95  for enabling the return member  96  to return the lug  94  to the first position P 1  to force the protrusion head  93  into engagement with the retaining hole  72 , and therefore the coupling block  80  is locked to the mounting member  70 . 
   As indicated, the quick release structure of the present invention allows quick mounting and dismounting of two detachable members (for example, the guard and the mounting member) without using tools, thereby saving much mounting and dismounting time. 
   The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.