Abstract:
An apparatus for testing mechanical endurance includes a bed for installing a workpiece, a clipping imitator capable of clipping a clipping ring of the workpiece, a hinging imitator capable of engaging with a hinge of the workpiece thereby making the workpiece tend to rotate, a cam, an oscillating rod following the cam, a pressure sensor capable of receiving pressure from the workpiece, a first arithmometer for taking count of pressure dropping the pressure sensor detects, and a second arithmometer for taking count of cam cycles. The oscillating rod includes first and second arms. The second arm engages the cam and can impel the clipping imitator to detach from the clipping ring. The first arm can press the workpiece down. In a cam cycle, if the workpiece does not break, the count of the first arithmometer equals to the count of the second arithmometer; or if breaks, the counts are different.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to testing apparatuses and, more particularly, to a testing apparatus for testing mechanical endurance. 
         [0003]    2. Description of Related Art 
         [0004]    In mechanical engineering, mechanical endurance testing is an important test for quality control of the products. Inventive testing devices for mechanical endurance are always desired in terms of improving the effectiveness of the testing process and increasing productivity. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is an exploded, isometric view of an exemplary embodiment of a testing apparatus, together with a cover of a mobile phone to be tested. 
           [0006]      FIG. 2  is an isometric, inverted view of the cover of  FIG. 1 . 
           [0007]      FIG. 3  is an assembled, isometric view of the testing apparatus and the cover of  FIG. 1 . 
           [0008]      FIG. 4  is a top plan view of  FIG. 3 , except that the cover of the mobile pone is omitted. 
           [0009]      FIG. 5  is a cross-sectional view of  FIG. 4 , taken along the line V-V in  FIG. 4 . 
           [0010]      FIGS. 6-9  are similar to  FIG. 5 , except that the cover of the mobile phone is shown and in different states. 
           [0011]      FIG. 10  is an enlarged view of the circled portion X of  FIG. 6 . 
           [0012]      FIG. 11  is a block diagram of the testing apparatus of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    Many aspects of the embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         [0014]    Referring to  FIGS. 1 through 3 , an exemplary embodiment of a testing apparatus is shown to be used to test mechanical endurance of a cover  1  of a mobile phone (not shown). 
         [0015]    The cover  1  includes a clipping ring  12  formed at a first end of the cover  1 , and a hinge  14  extending from a second end of the cover  1  opposite to the first end. The hinge  14  includes two projections  142  extending from the hinge  14  at both ends thereof. During the use of the mobile phone, the clipping ring  12  may break due to repeated clipping, and same for the hinge  14  due to repeatedly folding and unfolding. The clipping ring  12  and the hinge  14  are mechanically weak portions of the cover. Thus, the clipping ring  12  and the hinge  14  need to be tested to determine the mechanical endurance of the cover  1 . 
         [0016]    The testing apparatus includes a worktable  2 , a mechanism (not label), an electrical device (not label), a box  22  attached to a bottom of the worktable  2 , and four bolts  20  configured for supporting the worktable  2 . The mechanism is generally placed over the worktable  2 . The electrical device is placed under the worktable  2 . 
         [0017]    The mechanism includes an imitator device for imitating work actions (such as clipping and hinging) of the cover  1 , and a movement circulator (not label) for causing the cover  1  work repeatedly. 
         [0018]    The imitator device includes an installing member  3  fixed to the worktable  2  adjacent to a first end of the worktable  2 , two restricting blocks  32  fixed to opposite sides of the installing member  3 , a guiding block  34  fixed to the worktable  2  adjacent to an end wall  30  at a second end of the installing member  3 , and a clipping imitator (not labeled) slidably supported on the guiding block  34 . 
         [0019]    Referring to  FIGS. 4 through 6 , the installing member  3  includes a cantilever plate  36  extending out of the end wall  30  and over the guiding block  34 . The cover  1  is installed on the installing member  3  and restricted between the two restricting blocks  32 . A depressed portion  38  is defined in a top of the installing member  3  near the first end. A hinging imitator (not labeled) is formed in the depressed portion  38 . The hinging imitator includes a support  382 , and a pressing piece  384  (see  FIG. 10  for details). When the cover  1  is installed on the installing member  3 , the projections  142  of the cover  1  are pressed down by the pressing piece  384 , and roots of the projections  142  are supported by the support  382 , resulting in the cover  1  tending to rotate relative to the support  382 . Referring to  FIG. 1  again, a through hole  362  is defined in the installing member  3 , extending through the top and the bottom of the installing member  3 . A slot  301  is defined in the end wall  30  of the installing member  3 , under the cantilever plate  36 . 
         [0020]    A groove  342  is defined in the guiding block  34 . 
         [0021]    The clipping imitator includes a sliding block  31 , an elastic member such as a coiled spring  33 , a first elongated portion  35 , a second elongated portion  37 , and a gasket  39 . The sliding block  31  is slidably received in the groove  342  of the guiding block  34 , and includes an L-shaped clipping tongue  312  extending from a top of a first end of the sliding block  31 , and a blocking piece  314  extending down from a second end of the sliding block  31 . The blocking piece  314  resists against a first end wall of the guiding block  34 , to prevent the sliding block  31  from sliding out of the groove  342  through a second end wall of the guiding block  34 , wherein the first end wall of the guiding block  34  facing the end wall  30  of the installing member  3 . The first elongated portion  35  is fixed to the first end wall of the sliding block  31  via threaded connection. The second elongated portion  37  is fixed to the second end wall of the sliding block  31  via threaded connection. A free end of the first elongated portion  35  extends through the coiled spring  33  and the gasket  39 , and extends into the slot  301  of the installing member  3 . Two ends of the coiled spring  33  abut against the first end wall of the sliding block  31  and the gasket  39 , pushing the gasket  39  against the end wall  30  of the installing member  3 . When the cover  1  is installed on the installing member  3 , the clipping tongue  312  is extended through and engaged with the clipping ring  12 . 
         [0022]    The movement circulator includes an oscillating device (not label), a drive device (not label), and a speeder  50 . 
         [0023]    The oscillating device includes a rod holder  40  fixed to the worktable  2  and located adjacent to the second end wall of the guiding block  34 , an oscillating rod  44  rotatably attached to the rod holder  40 , and an elastic member such as a torsion spring  42  mounted between the rod holder  40  and the oscillating rod  44 . The oscillating rod  44  is capable of rotating while under the force of the torsion spring  42 . The oscillating rod  44  includes a first arm  441 , and a second arm  442  that is not aligned with the first arm  441 . The first arm  441  includes a first wheel  443  attached to a free end of the first arm  441 . The second arm  442  includes a second wheel  444  attached to a free end of the second arm  442 . 
         [0024]    The drive device includes a motor  51 , and a cam  53 . The motor  51  is fixed to the worktable  2  and located at a side away from the guiding block  34  of the rod holder  40 . The motor  51  includes a power shaft  510 . The cam  53  is fixed to the power shaft  510  and is capable of rotating with the power shaft  510 . A profile of the cam  53  engages with the second wheel  444 , thus driving the oscillating rod  44  to rotate reciprocally, in other words, the oscillating rod  44  is the follower of the cam  53 . The profile of the cam  53  includes six trace points A, B, C, D, E, and F as shown in  FIG. 5  which divide the profile of the cam  53  into six curves: a near dwell curve EF between the trace points E and F, a first rise curve FA between the trace points F and A, a middle dwell curve AB between the trace points A and B, a second rise curve BC between the trace points B and C, a far dwell curve CD between the trace points C and D, and a return curve DE between the trace points D and E. An avoiding hole  23  is defined in the worktable  2 . The cam  53  can be partly inserted through the avoiding hole  23  when rotating. 
         [0025]    The speeder  50  is installed to the worktable  2 , configured for controlling the speed of the motor  51 . 
         [0026]    Referring also to  FIG. 11 , the electrical device includes a pressure sensor  66 , a first arithmometer  61 , a photoelectric switch  64 , a second arithmometer  62 , and a control circuit  68 . The first arithmometer  61 , the photoelectric switch  64 , the second arithmometer  62 , and the control circuit  68  are received in the box  22 . 
         [0027]    The pressure sensor  66  is received in the through hole  362  of the installing member  3 . A top of the pressure sensor  66  extends out of the through hole  362  a little, so as to receive a pressure of the installed cover  1 . 
         [0028]    The first arithmometer  61  is electrically connected to the pressure sensor  66  via an electrical wire (not shown). The first arithmometer  61  is capable of recording a count of pressure dropping that the pressure sensor  66  detects. 
         [0029]    The photoelectric switch  64  includes an emitter  641 , and a receiver  642 . Light is emitted by the emitter  641  and received by the receiver  642 . The photoelectric switch  64  is placed under the cam  53 , and is set to allow only the far dwell curve CD to be able to enter between the emitter  641  and the receiver  642  so as to cut off the light path, so that only the far dwell curve CD of the cam  53  can change the photoelectric switch  64  to be in an off state. Thus, in each rotation cycle of the cam  53 , the photoelectric switch  64  turns to be in off state once. 
         [0030]    The second arithmometer  62  is electrically connected to the photoelectric switch  64 , and is configured to record a count the photoelectric switch  64  being in off state. 
         [0031]    Referring to  FIG. 6 , the cover  1  is installed on the installing member  3 , with the projections  142  inserted under the pressing piece  384  and supported on the support  382  of the installing member  3 , and the clipping ring  12  fitting about the clipping tongue  312  of the sliding block  31 . When the motor  51  is started the cam  53  is rotated anticlockwise. In a rotation cycle of the cam  53 , if the cover  1  does not break, the mechanism will perform the following. 
         [0032]    (a) When the oscillating rod  44  follows the middle dwell curve AB of the cam  53  via the second wheel  444  thereof, the oscillating rod  44  touches the cam  53  but does not touch the cover  1 , the torsion spring  42  between the rod holder  40  and the oscillating rod  44  is deformed, and the cover  1  applies pressure on the pressure sensor  66 . 
         [0033]    (b) Referring to  FIG. 7 , when the oscillating rod  44  follows the second rise curve BC, the second arm  442  is pushed by the cam  53  to move toward the second elongated portion  37 , driving the oscillating rod  44  to rotate relative to the rod holder  40 , and resulting in the first arm  441  moving upward and away from the cover  1 . When the second wheel  444  touches the second elongated portion  37 , the sliding block  31  is driven to slide toward the end wall  30  of the installing member  3 . The torsion spring  42  is further deformed, and the coil spring  33  is deformed. When the second wheel  444  reaches to the trace point C as shown in  FIG. 7 , the clipping tongue  312  of the sliding block  31  disengages from the clipping ring  12  of the cover  1 . Because the projections  142  of the cover  1  are pressed down by the pressing piece  384  and the roots of the projections  142  are supported by the support  382 , the cover  1  rotates relative to the support  382  after the clipping tongue  312  disengaging from the clipping ring  12 , resulting in the first end of the cover  1  tilting upwards to release pressure from the pressure sensor  66 . In fact, the cover  1  continues applying pressure on the pressure sensor  66  due to gravity, however, sensitivity of the pressure sensor  66  can be adjusted to counter gravity influence. When the oscillating rod  44  follows the far dwell curve CD, the clipping imitator and the cover  1  remain at the above-mentioned states when the second wheel  444  reaches to the trace point C. 
         [0034]    (c) Referring to  FIG. 8 , when the oscillating rod  44  follows the return curve DE, the torsion spring  42  biases the second arm  442  to rotate away from the second elongated portion  37  and the first arm  441  move toward the cover  1 . The second wheel  444  is disengaged from the second elongated portion  37 , the coil spring  33  biases the sliding block  31  to slide back. The first wheel  443  of the first arm  441  presses the cover  1  downwards, the clipping tongue  312  is engaged in the clipping ring  12 . The cover  1  applies pressure on the pressure sensor  66  again. After that, when the oscillating rod  44  follows the near dwell curve EF, the clipping imitator and the cover  1  remain at the above-mentioned states when the oscillating rod  44  follows the return curve DE. 
         [0035]    (d) Referring to  FIG. 6  again, when the oscillating rod  44  follows the first rise curve FA, the second arm  442  is pushed by the cam  53  to move toward the second elongated portion  37  but not touching the second elongated portion  37 , and the first arm  441  moves upward thereby disengaging from the cover  1 . After that, the oscillating rod  44  will follow the middle dwell curve AB again to enter into a next rotation cycle. 
         [0036]    According to what is described above, during a rotation cycle of the cam  53 , if the cover  1  does not break, the pressure sensor  66  will lose pressure only once when the oscillating rod  44  follows the far dwell curve CD. 
         [0037]    If the clipping ring  12  or the hinge  14  of the cover  1  breaks during a certain rotation cycle of the cam  53 , the cover  1  will tilt upward because of the broken clipping ring  12 , or the rotation tendency of the cover  1  will disappear because of the broken hinge  14 , resulting in the pressure sensor  66  detecting that pressure drops twice. Referring to  FIGS. 8 and 9 , and comparing  FIG. 9  with  FIG. 6 , take the clipping ring  12  as an example. If the clipping ring  12  does not broken, when the oscillating rod  44  follows the near dwell curve EF, the pressure sensor  66  receives pressure of the first arm  441  applying on the cover  1 , and when the second wheel  444  rolls along the middle dwell curve AB, the pressure sensor  66  receives pressure of the cover  1  (see  FIG. 6 ). However, if the clipping ring  12  breaks, when the oscillating rod  44  follows the near dwell curve EF, the pressure sensor  66  receives pressure of the first arm  441  applying on the cover  1 , but when the oscillating rod  44  follows the middle dwell curve AB, the first end of the cover  1  tilts upward resulting in the pressure sensor  66  losing pressure (see  FIG. 9 ). Thus, in this rotation cycle, the pressure sensor  66  loses pressure twice when the oscillating rod  44  follows the far dwell curve CD (see  FIG. 7 ) and the near dwell curve EF. 
         [0038]    Referring to  FIG. 11 , when the testing apparatus is started, the control circuit  68  controls the motor  51  to spin and reset the arithmometers  61 ,  62 . The first arithmometer  61  takes count of pressure dropping that the pressure sensor  66  detects. The second arithmometer  62  takes count of being in off state of the photoelectric switch  64 , namely takes count of number of turns of the cam  53 . The control circuit  68  receives and compares count data from the arithmometers  61 ,  62  in each rotation cycle of the cam  53 . If the count of the first arithmometer  61  equals to the count of the second arithmometer  62 , the control circuit  68  controls the motor  51  to keep on spinning. If the count of the first arithmometer  61  is different from the count of the second arithmometer  62 , the control circuit  68  controls the motor  51  to stop. Suppose that the cam  53  is in the Nth rotation cycle, and the clipping ring  12  or the hinge  14  of the cover  1  breaks. According to the hereinbefore description, the count of the second arithmometer  62  should be N, the count of the first arithmometer  61  should be N+1, and the motor  51  stops spinning. Thus, according to the count of the second arithmometer  62 , the mechanical endurance of the cover  1  can be known, in other words, the clipping ring  12  or the hinge  14  of the cover  1  can be used N times before breaking. 
         [0039]    Generally, the clipping ring  12  is mechanically weaker than the hinge  14 , so the present testing apparatus is often used to test the clipping ring  12  only. 
         [0040]    In other embodiments, the near dwell curve EF, the middle dwell curve AB, and the far dwell curve CD may be omitted, because these omitted curves are generally used to supply buffering action, in other words, they supply standstill period for the oscillating rod  44 . 
         [0041]    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 embodiments or sacrificing all of their material advantages, the examples hereinbefore described merely being exemplary embodiments of the invention.