Abstract:
A detecting apparatus for checking a detected item of an electrically conductive fastener attached to a workpiece includes a lower checking member for supporting the workpiece, an upper checking member movably set above the lower checking member, an electrical source, a processor, and an indicator. At least one of the two members includes a checking unit, which touches with the fastener and together with the fastener forms a detecting circuit when the upper checking member abuts against the workpiece. The detecting circuit is connected to the electrical source. A closed or open state of the detecting circuit indicates whether the detected item is eligible or ineligible. The processor controls the indicator to show the checking result according to the closed or open state of the detecting circuit. The detecting apparatus can greatly improve the checking efficiency and reliability, and suits mass production.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to detecting apparatuses. 
         [0003]    2. Description of Related Art 
         [0004]    On an assembly line, a mass of parts, such as fasteners installed in workpieces, may need to be checked whether they are attached to the workpieces properly. 
         [0005]    Referring to  FIG. 1 , a workpiece  90 , such as a chassis of a liquid crystal display (LCD), is shown. Electrically conductive fasteners of the workpiece  90 , which need to be checked, include two first rivets  6 , three second rivets  16 , two third rivets  8 , a fourth rivet  7 , a square piece  188 , and a long piece  19 . The first rivets  6  and the second rivets  16  are very much alike, but the first rivet  6  is longer. For these fasteners, detected items include: first, checking whether the fasteners are attached to the workpiece  90 ; second, checking heights of the first rivets  6  and the second rivets  16 ; third, checking whether the first rivets  6  and the second rivets  16  are attached to the workpiece  90  at predetermined places respectively; and fourth, checking linearity and/or position of the first rivets  6 , the second rivets  16 , and the third rivet  7 . 
         [0006]    Typically, the first and third detected items are visually checked by workmen. It is time-consuming and labor-intensive for the workmen, and a long time working will easily cause eye fatigue, which leads to a low checking accuracy and a high checking error rate. This way is inefficient and unfit for mass production. 
         [0007]    Referring to  FIGS. 2 and 3 , checking the heights of the first rivets  6  and the second rivets  16  is done manually by workmen using some tools, such as a height detecting tool  91 . Referring particularly to  FIG. 3 , a distance between a first cantilevered portion of the height detecting tool  91  and a reference plane, dimensioned as Dmax means a maximum permitted height of a part to be checked, while a distance between a second cantilevered portion of the height detecting tool  91  and the reference place, dimensioned as Dmin means a minimum permitted height of the part. In detection, the height detecting tool  91  is advanced towards one of the rivets, such as one rivet  6 , with a bottom of the tool  91  abutting on the surface of the workpiece  90 . The surface of the workpiece  90  acts as the reference plane. If the first cantilevered portion of the tool  91  corresponding to the Dmax can pass the rivet  6  and the second cantilevered portion thereof corresponding to the Dmin can not pass the rivet  6 , a height of the rivet  6  is eligible, otherwise, the height is ineligible. Moreover, different height rivets need different height detecting tools for checking. Thus, checking rivets in this way is complex and labor-intensive for the workmen, and it is inefficient and unfit for mass production. 
         [0008]    A detecting tool  92  shown in  FIG. 4  is commonly used for checking the accuracy of linearity and/or position of the first rivets  6 , the second rivets  16 , and the third rivet  7 . In use, the workman grips a handle of the tool  92 , and moves the tool  92  to the workpiece  90  to see whether the first rivets  6 , the second rivets  16 , and the third rivet  7  can enter corresponding detecting holes defined in the tool  92 . If each rivet enters the corresponding detecting hole smoothly, the linearity and/or position of the rivet is eligible; otherwise, it is ineligible. Checking in this way, it&#39;s hard for the workman to align the checking holes of the tool  92  with the rivets of the workpiece  90 , and the tool  92  may accidently bump the rivets in aligning process. Moreover, it is hard for the workman to judge contact between a number of walls bounding the corresponding holes and corresponding rivets, which seriously affects a detecting accuracy. 
         [0009]    What is desired, therefore, is a detecting apparatus suitable for use in mass production environment, which improves checking efficiency and reliability. 
       SUMMARY 
       [0010]    An exemplary detecting apparatus for checking at least one detected item of at least one electrically conductive fastener attached to a workpiece, includes a lower checking member configured to support the workpiece, an upper checking member movably set above the lower checking member, an electrical source, a processor, and an indicator. At least one of the lower checking member and the upper checking member comprises at least one checking unit corresponding to the at least one detected item of the fastener. The at least one checking unit can cooperate with the corresponding fastener to form a detecting circuit. The detecting circuit is connected to two electric poles of the electrical source. A closed or open state of the detecting circuit exists depending on whether the at least one checking unit touches the corresponding fastener when the upper checking member abuts against the workpiece to close the detecting circuit, and indicates whether the detected item is eligible or ineligible. The processor controls the indicator to show the checking result according to the closed or open state of the detecting circuit. 
         [0011]    Other advantages and novel features will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is an exploded, isometric view of a workpiece, together with electrically conductive fasteners which need to be checked; 
           [0013]      FIG. 2  is an isometric view of a typical height detecting tool checking a height of a fastener of the workpiece; 
           [0014]      FIG. 3  is a side, elevational view of  FIG. 2 ; 
           [0015]      FIG. 4  is an isometric view of a typical detecting tool used for checking accuracy of linearity and/or position and the workpiece; 
           [0016]      FIG. 5  is an isometric view of a detecting apparatus in accordance with an embodiment of the present invention; 
           [0017]      FIG. 6  is an exploded, isometric view of  FIG. 5 ; 
           [0018]      FIG. 7  is an electrical schematic of the present invention; 
           [0019]      FIG. 8  is a partial cut-away view of the detecting apparatus in operation and the workpiece of  FIG. 1 , showing the fasteners being eligible; 
           [0020]      FIG. 9  is an enlarged view of a circled portion IX of  FIG. 8 ; 
           [0021]      FIG. 10  is similar to  FIG. 8 , without the fasteners in place; 
           [0022]      FIG. 11  is similar to  FIG. 8 , showing accuracies of linearity and/or position of the fasteners being ineligible; 
           [0023]      FIG. 12  is similar to  FIG. 8 , showing heights of the fasteners being too high; and 
           [0024]      FIG. 13  is similar to  FIG. 8 , showing heights of the fasteners being too low. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    Referring to  FIGS. 5 and 6 , a detecting apparatus in accordance with an embodiment of the present invention includes an electric control box  50 , a table  20  for supporting the electric control box  50 , a brace  60  mounted on the box  50 , a safety light grid device  30  mounted at the front of the box  50 , a lower checking member  10  mounted on a bottom plate  62  of the brace  60 , a cylinder device  68  fixed to the brace  60 , and an upper checking member  80  fixed to the cylinder device  68  and suspended over the lower checking member  10 . 
         [0026]    A display  42 , an indicator light  44 , and a plurality of controller buttons  52  are set at the front of the electric control box  50 . An electrical source (not shown) and a processor  100  (see  FIG. 7 ) are set in the box  50 . 
         [0027]    The table  20  includes four wheels attached thereto for facilitating moving the detecting apparatus. 
         [0028]    The brace  60  includes an L-shaped supporter  64 . The bottom plate  62  is fixed at a bottom of the supporter  64 . A visible or audible alarm apparatus, such as an alarm annunciator  46 , set on a top of the supporter  64 . A hole, over which the lower checking member  10  is set, is defined in the bottom plate  62 . 
         [0029]    The display  42 , the indicator light  44 , and the annunciator  46  make up an indicator of the embodiment. 
         [0030]    The safety light grid device  30  includes a chassis  32  mounted to the electric control box  50 , and a light transmitter  341  and a light receiver  342  respectively mounted at opposite sides of the chassis  32 . The light transmitter  341  and the light receiver  342  are connected to an on-off circuit of the detecting apparatus. Light is transmitted from the light transmitter  341  to the light receiver  342  across a space between the two sides of the grid device  30 . When some part of an operator&#39;s body passes through the space to enter a working area of the detecting apparatus, the part of the body will cut off light between the light transmitter  341  and the light receiver  342 , which causes the detecting apparatus to stop thereby protecting the operator. 
         [0031]    Referring also to  FIG. 8 , the lower checking member  10  designed according to a shape of the workpiece  90  includes a board  11  made of electrically conductive material, at least one fixing block  12  made of electrically insulative material and fixed at a bottom of the board  11 , at least one steel checking sheath  13  correspondingly set in the fixing block  12 , at least one spring-loaded checking pin  14  slidably mounted in the board  11 , and at least one travel detector  15  fixed at the bottom of the board  11 , and placed under the checking pin  14 . A first end of a wire E is connected to the board  11 , and a second end of the wire E is connected to the electrical source in the electric control box  50 . A first end of a wire F is connected to the checking sheath  13 , and a second end of the wire F is connected to the electrical source. 
         [0032]    The upper checking member  80 , which is box-shaped and driven by the cylinder device  68  to move in an up-and-down direction, includes a base  81  made of electrically insulative material, a plurality of posts  5  mounted at a bottom of the base  81  for pressing against the workpiece which is placed on the lower checking member  10 . At least one spring-loaded checking pin  9  is slidably mounted at the bottom of the base  81 . At least one steel checking-sheath  4  is mounted in a bottom portion of the base  81 , and at least one steel fixing sheath  18  is mounted in a top portion of the base  81  corresponding to the checking sheath  4 . At least one spring-loaded checking pin  2  is slidably extended through the base  81  via the fixing sheath  18  and correspondingly through a column-shaped space defined in the checking sheath  4 . At least one spring-loaded checking block  1  is slidably mounted on the base  81  above the corresponding at least one checking pin  2 . The posts  5 , the checking pin  9 , the checking sheath  4 , the fixing sheath  18 , the checking pin  2 , and the checking block  1  are all made of electrically conductive material. A first end of a wire A is connected to the checking pin  2 , a first end of a wire B is connected to the checking block  1 , a first end of a wires C is connected to the checking sheath  4 , and a first end of a wire D is connected to the checking pin  9 . Second ends of wires A, B, C and D are connected to the electrical source in the electric control box  50 . 
         [0033]    Referring to  FIG. 7 , an electrical schematic of the present invention is shown. Signals, which are used to send orders to the processor  100  to start or stop the working of the detecting apparatus, can be transmitted from the safety light grid device  30  and the buttons  52  to the processor  100 . A signal, which is used to control the cylinder device  68  to move up and down, is transmitted from the processor  100  and the buttons  52  to the cylinder device  68 . The upper checking member  80  is driven by the cylinder device  68  to move towards or away from the lower checking member  10 . Detecting circuits (see below) are monitored by the processor  100  when the upper checking member  80  moves towards the lower checking member  10 . The processor  100  detects closed or open states of the detecting circuits, and then sends signals to the indicator made up of the display  42 , the indicator light  44 , and the annunciator  46 . 
         [0034]    In what follows, one first rivet  6 , one third rivet  8 , and one fourth rivet  7  are taken as examples for describing the working principle of the detecting apparatus in accordance with the embodiment. 
         [0035]    Referring to  FIG. 10 , and comparing  FIG. 10  with  FIG. 8 ,  FIG. 8  shows that the detected items of the first rivet  6 , the third rivet  8  and the fourth rivet  7  are eligible with zero-deviation, while  FIG. 10  shows a state that the first rivet  6 , the third rivet  8  and the fourth rivet  7  are not attached to the workpiece  90 . The workpiece  90  is placed on the lower checking member  10 . The upper checking member  80  driven by the cylinder device  68  moves down until its posts  5  just press on the workpiece  90 . 
         [0036]    For the fourth rivet  7 , if it is attached to the workpiece  90  as shown in  FIG. 8 , the checking pin  9  will be stopped by the fourth rivet  7  and pushed to move upward relatively to the upper checking member  80  with a spring around the checking pin  9  compressed, a detecting circuit including the checking pin  9  and the fourth rivet  7  closes, and current flows from the electrical source through the wire D, the checking pin  9 , the fourth rivet  7 , the workpiece  90 , the lower checking member  10 , the wire E, and back to the electrical source. The processor  100  receives a circuit closed signal and controls the indicator to indicate that the fourth rivet  7  is attached to the workpiece  90 ; otherwise, if the fourth rivet  7  is not attached to the workpiece  90 , the checking pin  9  moves downward with the upper checking member  80 , and enters a mounting hole for the fourth rivet  7  without contacting with the workpiece  90 , and the detecting circuit including the checking pin  9  and the fourth rivet  7  remains open and the processor  100  registers that the detecting circuit is open and controls the indicator to indicate that the fourth rivet  7  is not attached to the workpiece  90 . 
         [0037]    For the fourth rivet  8 , if it is attached to the workpiece  90 , the checking pin  14  is pressed by the fourth rivet  8  and moves downward with a spring around the checking pin  14  compressing, until it presses and activates a switch of the travel detector  15 , a detecting circuit including the checking pin  14 , the travel detector  15 , and the third rivet  8  closes. The processor  100  registers the closed detecting circuit and controls the indicator to indicate that the fourth rivet  8  is attached to the workpiece  90 ; otherwise, if the fourth rivet  8  is not attached to the workpiece  90 , the checking pin  14  can not be pressed, and the detecting circuit including the checking pin  14 , the travel detector  15 , and the third rivet  8  remains open. The processor  100  detects the open state and controls the indicator to indicate that the fourth rivet  8  is not attached to the workpiece  90 . 
         [0038]    Similarly, the ways for checking whether the fourth rivet  7  and the third rivet  8  are attached to the workpiece  90 , may be used to check the presence of other electrically conductive fasteners of the workpiece  90 . 
         [0039]    Referring to  FIG. 11  in conjunction with  FIG. 8 ,  FIG. 11  shows that accuracies of linearity and/or position of the first rivet  6  and the fourth rivet  7  are ineligible. A standard for judging whether the accuracy of linearity and/or position of the rivet  6 ,  7  is eligible is: if a deflection of linearity and/or position of the rivet  6 ,  7  is within an allowable tolerance, it is eligible. 
         [0040]    For the first rivet  6 , suppose when the accuracy of linearity and/or position of the first rivet  6  is eligible with zero-deviation, an axis of the column-shaped space bounded by the checking sheath  4  of the upper checking member  80  is in line with an axis of the rivet  6 . Suppose a diameter of a cross-section of the rivet  6  is equal to d6, a value of the allowable tolerance of the accuracy of linearity and/or position of the rivet  6  is equal to φ6, a diameter of a cross-section of the column-shaped space of the checking sheath  4  is equal to D6, and D6=d6+φ6. When the posts  5  of the upper checking member  80  press the workpiece  90 , if the accuracy of linearity and/or position of the rivet  6  is eligible, the rivet  6  enters the checking sheath  4  without touching it, a detecting circuit including the checking sheath  4  and the first rivet  6  remains open, and no current goes through a circuit made up of the wire C, the checking sheath  4 , the first rivet  6 , the workpiece  90 , the lower checking member  10 , the wire E, and the electrical source. The processor  100  registers the detecting circuit is open and controls the indicator to indicate that the linearity and/or position of the first rivet  6  is eligible; otherwise, if the rivet  6  is ineligible, the rivet  6  touches the checking sheath  4 , the detecting circuit including the checking sheath  4  and the first rivet  6  closes, and the processor  100  registers that the detecting circuit is closed and controls the indicator to indicate that the linearity and/or position of the first rivet  6  is ineligible. 
         [0041]    For the fourth rivet  7 , suppose when the linearity and/or position of the fourth rivet  7  is eligible with zero-deviation, an axis of the column-shaped space bounded by the checking sheath  13  is in line with an axis of the rivet  7 . Suppose a diameter of a cross-section of the rivet  7  is equal to d7, a value of the allowable tolerance of the accuracy of linearity and/or position of the rivet  7  is equal to φ7, a diameter of a cross-section of the column-shaped space of the checking sheath  13  is equal to D7, and D7=d7+φ7. When the posts  5  of the upper checking member  80  press out the workpiece  90 , if the linearity and/or position of the rivet  7  is eligible, the rivet  7  enters the checking sheath  13  without touching it, a detection circuit including the checking sheath  13  and the fourth rivet  7  remains open, and no current goes through a circuit made up of the wire D, the checking pin  9 , the fourth rivet  7 , the checking sheath  13 , the wire F, and the electrical source. The processor  100  registers that the detecting circuit is open and controls the indicator to indicate that the linearity and/or position of the first rivet  6  is eligible; otherwise, if the linearity and/or position of the rivet  6  is ineligible, the rivet  6  touches the checking sheath  4 , and the detecting circuit including the checking sheath  13  and the fourth rivet  7  closes, and the processor  100  registers that the detecting circuit is closed and controls the indicator to indicate that the linearity and/or position of the first rivet  6  is ineligible. 
         [0042]    Referring to  FIG. 12  in conjunction with  FIGS. 8 and 9 ,  FIG. 12  shows that height of the first rivet  6  is too high. A standard for judging whether the height of the rivet  6  is eligible is: if a deflection of height of the rivet  6  is limited in an allowable tolerance, it is eligible; otherwise, it is ineligible, and especially if a value of height of the rivet  6  is not less than an upper limitation of the allowable tolerance, the rivet  6  is too high. 
         [0043]    Suppose a value of the allowable tolerance of the height of the rivet  6  is equal to b. When the posts  5  of the upper checking member  80  press the workpiece  90 , if the height of the rivet  6  is eligible, the checking pin  2  of the upper checking member  80  is pushed by the rivet  6  and moves upward, and a moving distance of the checking pin  2  is less than 2δ. Particularly, if there is no deflection of the height of the rivet  6 , a distance between a touching piece  17  (shown in  FIG. 9 ) of the checking pin  2  and the checking block  1  is equal to δ, and a distance between the touching piece  17  and the fixing sheath  18  is also equal to δ. At the same time, a first detecting circuit including the checking pin  2  and the first rivet  6  closes, and current of a first circuit flows from the electrical source through the wire A, the checking pin  2 , the first rivet  6 , the workpiece  90 , the lower checking member  10 , the wire E, and back to the electrical source. Because the checking pin  2  does not touch the checking block  1 , a second detecting circuit including the checking pin  2  and the checking block  1  remains open, and no current goes through a second circuit made up of the wire B, the checking block  1 , the checking pin  2 , the first rivet  6 , the workpiece  90 , the lower checking member  10 , the wire E, and the electrical source. The processor  100  registers that the first detecting circuit is closed and the second detecting circuit is open, and then controls the indicator to indicate that the height of the rivet  6  is eligible. Otherwise, if the height of the rivet  6  is too high, the checking pin  2  of the upper checking member  80  is pushed by the rivet  6  and moves upward, and a moving distance of the checking pin  2  is not less than 2δ. At the same time, the first detecting circuit including the checking pin  2  and the first rivet  6  closes, and current goes through the first circuit. Because the checking pin  2  moves upward so long a distance that the checking pin  2  touches the checking block  1 , the second detecting circuit including the checking pin  2  and the checking block  1  closes, and current goes through the second circuit. The processor  100  registers that the first and second detecting circuits are closed and controls the indicator to indicate that the height of the rivet  6  is ineligible and too high. 
         [0044]    Similarly, the way for checking whether the height of the first rivet  6  is too high, may be used for checking whether the longer first rivet  6  is misplaced on a place of the shorter second rivet  16  should be instead. 
         [0045]    Referring to  FIG. 13 , in conjunction with  FIGS. 8 and 9 ,  FIG. 13  shows that height of the first rivet  6  is too low. A standard for judging whether the height of the rivet  6  is eligible is: if a deflection of height of the rivet  6  is limited in an allowable tolerance, it is eligible; otherwise, it is ineligible, and if a value of a height of the rivet  6  is less than a lower limitation of the allowable tolerance, the rivet  6  is too low. 
         [0046]    When the posts  5  of the upper checking member  80  press the workpiece  90 , if the height of the rivet  6  is eligible, the checking pin  2  of the upper checking member  80  is propped up by the rivet  6  and moves upward, and a moving distance of the checking pin  2  is less than 2δ. At the same time, a detecting circuit including the checking pin  2  and the first rivet  6  closes, and current flows from the electrical source through the wire A, the checking pin  2 , the first rivet  6 , the workpiece  90 , the lower checking member  10 , the wire E, and back to the electrical source. The processor  100  receives a circuit closed signal and controls the indicator to indicate that the height of the rivet  6  is eligible. Otherwise, if the height of the rivet  6  is too low to touch the checking pin  2  of the upper checking member  80 , the detecting circuit including the checking pin  2  and the first rivet  6  remains open, and the processor  100  registers that the circuit is open and controls the indicator to indicate that the height of the rivet  6  is ineligible and too low. 
         [0047]    Similarly, the way for checking whether the height of the first rivet  6  is too low, may be used for checking whether the shorter second rivet  16  is misplaced on a place of the longer first rivet  6  should be instead. 
         [0048]    Information of closing or opening of each circuits above is collected, judged and processed by the processor  100 . 
         [0049]    According to the above description, a closed or open state of each circuit only relies on the corresponding detecting circuit including the fastener that needs to be checked and checking parts correlative with the fastener. Thus, in fact, what the processor  100  has done is collecting, judging and processing of information of closing or opening of the detecting circuits. The processor  100  sends processing result to the indicator made up of the display  42 , the indicator light  44  and the bottom plate  62 . If the indicator receives a result that all detected items of all the fasteners are eligible, the indicator light  44  shines and the display  42  indicates the workpiece  90  has passed. If the indicator receives a result that some detected items of the fasteners are ineligible, the bottom plate  62  alarms and the display  42  shows locations of the ineligible fasteners and the corresponding ineligible detected items. In other embodiments, an indicator may be made up of one or two of the display  42 , the indicator light  44  and the bottom plate  62 . 
         [0050]    Moreover, according to different needs of checking precision, the springs in the embodiment may be other elastic elements instead, such as acrylic resin, elasticity rubber, and hydraulic mechanism. 
         [0051]    It is believed that the present embodiments and their advantages is understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.