Patent Publication Number: US-6990881-B2

Title: Workpiece holding-down structure for blind cutting machine

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to a blind cutting machine and, more specifically, to a workpiece holding-down structure for use in a blind cutting machine to hold down a blind for cutting. The invention relates also to a blind cutting machine having such a workpiece holding-down structure. 
   2. Description of the Related Art 
   Due to mass production, blind manufacturers provide few sizes (lengths of headrail, bottom rail and slats) for each model. However, a house commonly has windows of different sizes subject to different lighting designs. Distributors or upholsterers may have to cut blinds purchased from factories subject to different windows to be covered with blinds. Various blind cutting machines have been disclosed, and have appeared on the market. A blind cutting machine generally comprises a cutter unit and a workpiece feeder. During operation, the blind to be cut is put in the workpiece feeder in a horizontal position and inserted through the cutter unit, and then the cutter unit is started to cut the blind. When cutting a blind, the parts of the blind must be gathered and held down in the cutting position. If the parts of the blind are not gathered and held down in the cutting position, the parts may be cut at different lengths, and the cut edges of the parts of the blind may be squeezed against one another, resulting in the presence of burs at the cut edges. In order to eliminate this problem, a vice or the like is used in the workpiece feeder to hold down the front ends of the parts of the blind in front of the cutter unit. However, because a blind is comprised of a number of elongated parts, simply holding down the front ends of the parts cannot keep the parts tightly together in a good order. Therefore, the operator has to arrange the rear ends of the parts in the workpiece feeder manually, and then insert the front ends of the parts of the blind through the cutter unit. This cutting procedure takes much time and labor, and the operator will tire very soon. When the operator became weary, he (she) may be unable to control the cutting quality well. Further, a vice for this purpose is complicated, and its use deters the speed of the cutting operation. 
   SUMMARY OF THE INVENTION 
   The present invention has been accomplished under the circumstances in view. It is therefore the main object of the present invention to provide a workpiece holding-down structure for blind cutting machine, which improves the blind cutting efficiency of the blind cutting machine. 
   It is another object of the present invention to provide a workpiece holding-down structure for blind cutting machine, which is simple and inexpensive to manufacture. 
   To achieve these objects of the present invention, the workpiece holding-down structure comprises a workpiece feeder having a front side abutted against a cutter unit of the blind cutting machine, and a rear side; and a clamp installed in the workpiece feeder and adapted to hold down a blind for cutting by the cutter unit of the blind cutting machine. The clamp has a clamping bar unit fastened pivotally with a bottom wall of the workpiece feeder near a first lateral side of the workpiece feeder and adapted to push a blind been put in the workpiece feeder toward a second lateral side of the workpiece feeder and to further hold down the blind for cutting. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a top view showing a workpiece holding-down structure installed in a blind cutting machine according to the present invention. 
       FIG. 2  is a perspective view of the workpiece holding-down structure according to a first embodiment of the present invention. 
       FIG. 3  is an exploded view of the workpiece holding-down structure according to the first embodiment of the present invention. 
       FIG. 4  is a schematic drawing showing a position of the clamp of the workpiece holding-down structure according to the first embodiment of the present invention. 
       FIG. 5  is a schematic drawing showing another position of the clamp of the workpiece holding-down structure according to the first embodiment of the present invention. 
       FIG. 6  is a schematic drawing showing a position of the clamp of the workpiece holding-down structure according to a second embodiment of the present invention. 
       FIG. 7  is a schematic drawing showing another position of the clamp of the workpiece holding-down structure according to the second embodiment of the present invention. 
       FIG. 8  is a schematic drawing showing a position of the clamp of the workpiece holding-down structure according to the third embodiment of the present invention. 
       FIG. 9  is a schematic drawing showing another position of the clamp of the workpiece holding-down structure according to the third embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , a blind cutting machine  1  is shown comprised of a cutter unit  20 , and a workpiece feeder  30 . 
   The cutter unit  20  has a cutter tool adapted to be reciprocated horizontally to cut off the workpiece been set in the reciprocating path of the cutter tool. The cutter unit  20  is constructed according to conventional techniques. Because the cutter unit  20  is of the known art, no further detailed description in this regard is necessary. The workpiece feeder  30  is made from a metal plate by stamping, having a front side  30   a  and a rear side  30   b . The front side  20   a  of the workpiece feeder  30  is abutted against the cutter unit  20  of the blind cutting machine  1 . 
   Referring to  FIGS. 2 and 3 , the workpiece holding-down structure for blind cutting machine according to the first embodiment of the present invention is comprised of the aforesaid workpiece feeder  30  and a clamp  40 . The clamp  40  comprises a mounting base  41 , a clamping bar unit  42 , and a positioning mechanism  43 . 
   The mounting base  41  comprises a rectangular base plate  411  and a side plate  412  extended from one side of the base plate  411  at right angles. The base plate  411  has a screw hole  411   a , and a plurality of positioning holes  411   b  equiangularly spaced around the screw hole  411   a . According to this embodiment, the number of the positioning holes  411   b  is 8. Alternatively, the base plate  411  can be made having 16 or more locating holes. The side plate  412  has two mounting holes  412   a  fixedly fastened to one vertical lateral sidewall of the workpiece feeder  30  by screws near the front side  30   a.    
   The clamping bar unit  42  comprises a clamping bar  421 , a pivot bolt  422 , and a handle  423 . The clamping bar  421  has a front end  421   a , a rear end  421   b , a pivot hole  421   c  in the front end  421   a , and a threaded locating hole  421   d  in the front end in parallel to the pivot hole  421   c . The pivot bolt  422  is inserted through the pivot hole  421   c  of the clamping bar  421  and threaded into the screw hole  411   a  to secure the clamping bar  421  to the mounting base  41 , enabling the clamping bar  421  to be turned about the pivot bolt  422 . The handle  423  is fixedly fastened to the clamping bar  421 , having one end protruded over the top side of the clamping bar  421 . 
   The positioning mechanism  43  is comprised of a locating rod  431 , a spring member  432 , and a steel ball  433 . The locating rod  431  has a threaded rod body  431   a  and a tip  431   b  axially extended from one end of the threaded rod body  431   a . The diameter of the tip  431   b  is smaller than the threaded rod body  431   a . The threaded rod body  431   a  is threaded into the threaded locating hole  421   d  of the clamping bar  421 , keeping the tip  431   b  suspended inside the threaded locating hole  421   d . The spring member  432  is sleeved onto the tip  431   d  of the locating rod  431  and stopped at the bottom side of the threaded rod body  431   a  of the locating rod  431 . The steel ball  433  is stopped at the bottom end of the spring member  432  remote from the locating rod  431 . When installed, the spring member  432  imparts a downward pressure to the steel ball  433 . 
   Referring to  FIGS. 4 and 5 , during cutting operation, the blind A is put in the workpiece feeder  30 , and then the operator pulls the handle  423  to turn the clamping bar  421  about the pivot bolt  422  and to force the rear end  421   b  of the clamping bar  421  against the blind A, and at the same time, the steel ball  433  is shifted from one positioning hole  411   b  of the mounting base  41  to another. When the parts of the blind A gathered together and stopped firmly in place against one vertical sidewall of the workpiece feeder  30  by the clamping bar  421 , the steel ball  433  is engaged into the corresponding positioning hole  411   b  to lock the clamping bar  421 . After cutting, the operator moves the handle  423  in the reversed direction to release the clamping bar  421  from the blind A, and then removes the blind A from the workpiece feeder  30 . 
   The aforesaid first embodiment of the present invention has numerous advantages. One advantage is that the blind holding-down structure enables the workpiece to be rapidly and firmly clamped in position for cutting, improving the cutting efficiency. The other advantage of the blind holding-down structure is its simple structure for easy installation and maintenance. 
     FIGS. 6 and 7  show the second embodiment of the present invention. According to this embodiment, the clamping bar unit  42  is comprised of two clamping bars  421 , two pivot bolts  422 , and one handle  423 . The clamping bars  421  each have a front end  421   a , a rear end  421   b , and a toothed portion  421   e  at the front end  421   a . The clamping bars  421  are respectively pivoted to the bottom wall of the workpiece feeder  30  at one side by the pivot bolts  422 , keeping the toothed portions  421   e  meshed. The handle  423  is fixedly fastened to one clamping bar  421 , having one end protruded over the top side of the corresponding clamping bar  421 . After the blind A has been put in the workpiece feeder  30  during a blind cutting operation, the operator needs only to pull the handle  423 , and the clamping bars  421  are simultaneously turned about the respective pivot bolts  422  toward each other to hold down the parts of the blind A for cutting. Because two clamping bars  421  are used and clamped on the blind A, the parts of the blind A are tightly held down in position for cutting. 
     FIGS. 8 and 9  show the third embodiment of the present invention. According to this embodiment, the clamp comprises two mounting bases  41 , and a clamping bar unit  42 . The clamping bar unit  42  is comprised of two clamping bars  421 , two pivot bolts  422 , a handle  423 , and a link  424 . The clamping bars  421  each have a front end  421   a  and a rear end  421   b . The front ends  421   a  of the clamping bars  421  are respectively pivoted to the mounting bases  41  in the workpiece feeder  30  by the pivot bolts  422 . The handle  423  is fixedly fastened to the clamping bar  421 , having one end protruded over the top side of the clamping bar  421 . The link  424  is coupled between the second ends  421   b  of the clamping bars  421 , keeping the clamping bars  421  in parallel. When the operator pulling the handle  423  toward the blind A in the workpiece feeder  30 , the clamping bars  421  and the link  424  are simultaneously moved toward the blind A, thereby causing one long side of the link  424  to be pressed on the blind against one vertical sidewall of the workpiece feeder  30 , and therefore the blind A is held down in position for cutting. 
   In the aforesaid embodiments of the present invention, the positioning mechanism can be set in one of a series of positions (8 or 16 subject to the number of the locating holes). Any of a variety of stepless locking means may be used to lock the clamping bar unit. However, the positioning mechanism is not imperative. For cutting blinds of light materials, the positioning mechanism can be eliminated.