Abstract:
A cup attaching apparatus for attaching a cup, used during processing of an eye glass lens, to the lens, the apparatus includes: a placing portion onto which the lens is placed; a holding portion for detachably holding the cup; a supporting portion for supporting the holding portion; a moving mechanism for moving the supporting portion in an optical axis direction of the placed lens; and a pressure regulating mechanism for preventing a cup attaching force from exceeding a predetermined pressure.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a cup attaching apparatus for attaching a cup used during the processing of an eyeglass lens to a subject lens. 
   As a preliminary operation before a subject lens is processed by a lens processing apparatus, a cup used during processing is attached to the lens by a cup attaching apparatus called an aligner or blocker. The cup attaching apparatus of the following type is available. A lens to which a mark is applied onto its optical center or the like using a lens meter is illuminated so that an image of the lens is projected onto a screen, and a cup attaching position is aligned by observing an image of the mark projected onto the screen and a reference scale. In such an apparatus, after the alignment of the lens is completed, an arm to which the cup has been attached in advance is manually pushed down to allow the cup to be pressed against the lens and suckingly fixed to the lens. 
   However, in the case of a lens coated with a reflection preventing film (anti-reflection film) or the like, the conventional cup attaching apparatus causes a problem in that if the force with which the cup is attached is too strong (too large), the lens is deformed and the coating is cracked. In addition, with the apparatus in which the arm is manually operated, since there are individual differences in the force with which the arm is pushed down to attach the cup, there are variations due to the difference in the operator. 
   SUMMARY OF THE INVENTION 
   In view of the above-described problems, it is An object of the present invention to provide a cup attaching apparatus which makes it possible to prevent an excess force (more than is necessary) from being applied to the subject lens and to attach the cup to the lens with a stable force. 
   To attain the above object, the present invention is characterized by having the following features. 
   (1) A cup attaching apparatus for attaching a cup, used during processing of an eyeglass lens, to the lens, the apparatus comprising: 
   a placing portion onto which the lens is placed; 
   a holding portion for detachably holding the cup; 
   a supporting portion for supporting the holding portion; 
   a moving mechanism for moving the supporting portion in an optical axis direction of the placed lens; and 
   pressure regulating means for preventing a cup attaching force from exceeding a predetermined pressure. 
   (2) The apparatus of (1), wherein the pressure regulating means includes sensing means for sensing a state that pressure exceeding the predetermined pressure is applied to the placed lens. 
   (3) The apparatus of (1), wherein: 
   the moving mechanism includes a pressing portion that is movable relative to the supporting portion in the optical axis direction of the placed lens and to which pressing force for moving the supporting portion in the optical axis direction of the placed lens is applied; and 
   the pressure regulating means includes a deformable member that is provided between the pressing portion and the supporting portion and that is deformed when pressing force exceeding the predetermined pressure is applied to the pressing portion. 
   (4) The apparatus of (3), wherein the pressure regulating means includes adjusting means for adjusting an initial deforming force of the deformable member. 
   (5) The apparatus of (1), wherein: 
   the holding portion is supported by the supporting portion to be movable in the optical axis direction of the placed lens; 
   the moving mechanism includes a pressing portion to which pressing force for moving the supporting portion in the optical axis direction of the placed lens is applied; and 
   the pressure regulating means includes a deformable member that is provided between the supporting portion and the holding portion and that is deformed when pressing force exceeding the predetermined pressure is applied to the pressing portion. 
   (6) The apparatus of (5), wherein the pressure regulating means includes adjusting means for adjusting an initial deforming force of the deformable member. 
   (7) The apparatus of (1), wherein: 
   the moving mechanism includes a motor for moving the supporting portion in the optical axis direction of the placed lens; and 
   pressure regulating means includes control means for controlling driving of the motor. 
   (8) The apparatus of (7), wherein: 
   the pressure regulating means includes detecting means for detecting a drive load of the motor; and 
   the control means controls driving of the motor based on a result of detection by the detecting means. 
   (9) The apparatus of (7), wherein: 
   the pressure regulating means includes setting means for variably setting the cup attaching force; and 
   the control means controls driving of the motor based on the set cup attaching force. 
   (10) A cup attaching apparatus for attaching a cup, used during processing of an eyeglass lens, to the lens, the apparatus comprising: 
   a placing portion onto which the lens is placed; 
   a holding portion for detachably holding the cup; 
   a supporting portion for supporting the holding portion; 
   a pressing portion that is movable relative to the supporting portion in an optical axis direction of the placed lens, and to which pressing force for moving the supporting portion in the optical axis direction of the placed lens is applied; and 
   a deformable member that is provided between the pressing portion and the supporting portion and that is deformed when pressing force exceeding a predetermined pressure is applied to the pressing portion. 
   (11) The apparatus of (10), further comprising: 
   an adjusting member for adjusting an initial deforming force of the deformable member. 
   (12) A cup attaching apparatus for attaching a cup, used during processing of an eyeglass lens, to the lens, the apparatus comprising: 
   a placing portion onto which the lens is placed; 
   a holding portion for detachably holding the cup; 
   a supporting portion for supporting the holding portion to be movable in an optical axis direction of the placed lens; 
   a pressing portion to which pressing force for moving the supporting portion in the optical axis direction of the placed lens is applied; and 
   a deformable member that is provided between the supporting portion and the holding portion and that is deformed when pressing force exceeding a predetermined pressure is applied to the pressing portion. 
   (13) The apparatus of (12), further comprising: 
   an adjusting member for adjusting an initial deforming force of the deformable member. 
   The present disclosure relates to the subject matter contained in Japanese patent application No. 2001-87108 (filed on Mar. 26, 2001), which is expressly incorporated herein by reference in its entirety. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIGS. 1A and 1B  are external views of a cup attaching apparatus in accordance with a first embodiment; 
       FIG. 2  is a side elevational view of the interior of the cup attaching apparatus; 
       FIG. 3  is a top view of the cup attaching apparatus; 
       FIG. 4  is a side elevational view of the interior of the cup attaching apparatus in accordance with a second embodiment; and 
       FIG. 5  is a schematic diagram of the cup attaching apparatus in accordance with a third embodiment. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to the drawings, a description will be given of the embodiments of the invention.  FIGS. 1A and 1B  are external views of a cup attaching apparatus  1  in accordance with a first embodiment of the invention, in which  FIG. 1A  is a front elevational view, and  FIG. 1B  is a side elevational view.  FIG. 2  is a side elevational view of the interior of the apparatus  1 , and  FIG. 3  is a top view of the apparatus  1 . It should be noted that  FIGS. 1A ,  1 B, and  3  are diagrams in a case where a screen plate  6  is positioned on a reference axis L, and  FIG. 2  is a diagram in a case where a cup fitting portion  9  is positioned on the reference axis L. 
   In  FIGS. 1A ,  1 B, and  2 , reference character L denotes a reference axis for cup attachment (alignment) . An illuminating light source  3  located on the reference axis L is provided inside a main body housing  2 , and a condenser lens  4  is disposed on top of the main body housing  2 . The lens  4  collimates the illumination light from the light source  3  into a parallel beam of light. Three lens receiving pins  5  onto which a subject lens LE is placed are disposed on an upper surface of the lens  4  with the reference axis L as a center. It should be noted that the number of the pins  5  is not limited to three, and may be any arbitrary number that can stably place the lens LE on the pins  5  (such that the optical axis of the lens LE becomes substantially parallel with the reference axis L). Furthermore, tubular members may be used instead of the pins. 
   A cylindrical portion  11  is integrally formed in the rear of the main body housing  2 , and a shaft  12  constituting a part of a cup attaching portion  10  is held inside this cylindrical portion  11  in such a manner as to be movable vertically in the direction of the reference axis L and to be rotatable. The shaft  12  is constantly urged upward (in the direction of arrow B in  FIG. 2 ) which is an opposite direction to a cup attaching direction (in the direction of arrow A in  FIG. 2 ) by means of a spring  13  provided between the shaft  12  and a bottom surface of the main body housing  2 . Namely, the spring  13  has an urging force for lifting the shaft  12 , as shown in  FIG. 2 , against the load of the cup attaching portion  10  provided on an upper portion of the shaft  12 . Reference numeral  18  denotes a removal preventing member for ensuring that the shaft  12  is prevented from being removed upward by the urging force of the spring  13 , and the removal preventing member  18  is attached to a lower end of the shaft  12 . 
   The arm  7  for holding the screen plate  6  and an arm  8  for supporting the cup fitting portion (cup holding portion)  9  for holding a cup C are fixed to an upper portion of the shaft  12  by means of screws  7 S and  8 S, respectively. The fitting portion  9  to which a proximal portion Cb of the cup C is fitted so as to be held is provided on the underside of a distal end of the arm  8 , and the cup C is detachable from the fitting portion  9 . 
   In addition, a rotating knob  14  having a pressing surface which is pressed by an operator in the cup attaching direction (in the direction of arrow A) is provided on an arm upper portion  8   a  which is located on the rotational axis of the shaft  12 . An inner surface of the knob  14  is guided by the arm upper portion  8   a , and the knob  14  is movable vertically in the direction of the reference axis L, and is non-rotatable with respect to the arm  8  by an unillustrated restricting member. As the knob  14  is rotated, the arm  7  and the arm  8 , together with the shaft  12 , are rotatable 90° from the position shown in  FIG. 1  to the position, shown in  FIG. 2 , where the center of the cup C is aligned with the reference axis L. 
   A spring  15  is inserted between a recessed portion formed in the arm upper portion  8   a  and the knob  14  so that the knob  14  is constantly urged upward (in the direction of arrow B) and has a structure for preventing the removal of the knob  14  from the arm upper portion  8   a , as shown in the drawing. The spring  15  has a spring constant greater than that of the spring  13 , so that the spring  15  has such a spring force that its urging force is greater than the upwardly urging force of the spring  13  and that the spring  15  is deformed when a pressing force greater than a predetermined pressure is applied thereto by the pressing down of the knob  14 . 
   In addition, a spring-force adjusting screw  16  and a spring presser plate  17  are inserted inside the knob  14 . The presser plate  17  is provided with internal threads threadingly engaged with the adjusting screw  16 . If the adjusting screw  16  is rotated, the presser plate  17  moves vertically in the direction of the reference axis L, thereby adjusting an initial deforming spring force (the force with which the cup C is attached to the lens LE, i.e., pressing force) of the spring  5 . In addition, as shown in  FIG. 3 , a scale  14   a  for the attaching force is provided on the upper surface of the knob  14 , and the value of the scale  14   a  indicated by an arrow  16   a  provided on the upper surface of the adjusting screw  16  is the set attaching force. In case where the attaching force is to be changed, adjustment is made by turning the adjusting screw  16  by using a hexagonal wrench. In this embodiment, the attaching force is made changeable continuously in the range of 1 to 5 kg (may be changeable in a stepwise manner). 
   A description will be given of the operation of the apparatus constructed as described above. Here, a description will be given of a case where alignment is made with the optical center of the lens LE (the cup C is mounted by aligning its center with the optical center of the lens LE). 
   First, the operator positions the center of the screen plate on the reference axis L in advance, and fits the cup C to the fitting portion  9 . When the cup C is fitted, the proximal portion Cb of the cup C is inserted and fitted in the fitting portion  9  such that the cup C is oriented in a predetermined direction in conformity with a positioning mark  8   c  provided on an upper portion of the distal end of the arm  8 . Next, the lens LE with a marked point provided in advance at its optical center by a lens meter or the like is placed on the lens receiving pins  5 . At this time, the lens LE is placed stably such that the optical axis of the lens LE and the reference axis L become substantially parallel. The lens LE is illuminated by the illumination light from the light source  3 , and its image is projected onto the screen plate  6 . Further, as shown in  FIG. 3 , an image  21  of the marked point provided on the lens LE is aligned with a cross reticle mark  6   a  on the screen plate  6 . Namely, a central image  21   a  of the marked point is aligned with the center of the cross reticle mark  6   a , and in a case where the lens LE has cylindrical power, images  21   b  and  21   c  of the marked point which indicate the axial angle of astigmatism (cylinder) are adjusted so as to be located on the horizontal line of the cross reticle mark  6   a.    
   Subsequently, the arm  8  (and the arm  7  as well) is rotated 90° by the knob  14  to align the center of the cup C with the reference axis L, and the upper portion (pressing surface) of the knob  14  is pressed down (in the direction of arrow A). If the knob  14  is pressed down, the spring  13  first undergoes compressive deformation, and the entire movable portions such as the knob  14 , the arm  7 , the arm  8 , and the shaft  12  move downward (in the direction of arrow A) . After the cup C has abutted against the upper surface of the lens LE, if the knob  14  is pressed down, the cup C sucks the lens LE. If the knob  14  is further pressed down, the spring  15  begins to undergo compressive deformation. Even if the operator presses down the knob  14 , the arm  8  and the like are not lowered further than that, and the spring  15  absorbs the pressing force (kinetic energy) of the operator attempting to press down the knob  14 . At this point of time, the operator senses that the attachment of the cup C has been completed from the manual response, i.e., from the reaction force the time of pressing the knob  14  and its stroke, and the operator weakens (stops) the force for pressing down the knob  14  and finishes the operation. 
   As the spring  15  undergoes compressive deformation after the cup C has been attached to the upper surface of the lens LE by pressing down the knob  14 , it is possible to suppress the pressing force applied to the lens LE by the operator more than is necessary. For this reason, it is possible to prevent a situation in which the lens LE is deformed, and the cracking of the coating such as the reflection preventing film coated on the lens surface occurs. 
   In addition, it is possible to vary the attaching force with respect to the lens LE by changing the initial deforming force of the spring  15  depending on the material, shape, and type (suction type, seal type, etc.) of the cup C as well as the material and shape of the lens LE and the kind of coating on the lens LE. For this reason, the adjusting screw  16  is rotated with the hexagonal wrench to allow the arrow  16   a  to be directed toward a value to be set on the scale  14   a.    
   In addition, in a case where an unskilled operator attaches the cup C to the lens LE, such an operator is unable to grasp the attaching force to be applied. With the mechanism of this apparatus, however, since the attaching force with respect to the lens LE is maintained at a substantially fixed level, the apparatus is particularly effective for unskilled operators. 
   In addition, even in a case where a skilled operator is busily engaged with the operation and has pressed down the knob  14  abruptly contrary to his or her intention, since the spring  15  absorbs the attaching force applied to the lens LE (pressing force of the knob  14 ), an excess force is not applied to the lens LE. 
     FIG. 4  is a diagram explaining a cup attaching apparatus  1 ′ in accordance with a second embodiment of the invention, and elements identical to those of the preceding embodiment are denoted by the same reference numerals. A fitting portion  9 ′ for detachably holding the cup C is held on the underside of a distal end of an arm  8 ′ in such a manner as to be movable vertically in the direction of the reference axis L and to be non-rotatable. A spring  15 ′ for urging the fitting portion  9 ′ downward (in the direction of arrow A) relative to the arm  8 ′ is provided in a recessed portion  8   b  formed in the distal end of the arm  8 ′. In the same way as the spring  15  in the preceding embodiment, this spring  15 ′ has such a spring force that its urging force is greater than the upwardly urging force (in the direction of arrow B) of the spring  13  and that the spring  15 ′ is deformed when pressure greater than a predetermined pressure is applied thereto. Further, a spring presser plate  17 ′ for adjusting the initial deforming spring force of the spring  15 ′ as well as a spring-force adjusting screw  16 ′ for moving the spring presser plate  17 ′ vertically in the direction of the reference axis L are provided in the recessed portion  8   b.  It should be noted that, in this embodiment, a rotating knob  14 ′ is fixed to the arm  8 ′. 
   In this construction as well, if the knob  14 ′ is pressed down to allow the cup C to suck the lens LE, and the knob  14 ′ is further pressed down, the spring  15 ′ begins to undergo compressive deformation and absorbs the pressing force (kinetic energy) of the operator attempting to press down the knob  14 ′. Since the operator senses that the attachment of the cup C has been completed from the manual response, i.e., from the reaction force at the time of pressing the knob  14 ′ and its stroke, the operator weakens (stops) the force for pressing down the knob  14 ′ and finishes the operation. Consequently, it is possible to suppress the pressing force applied to the lens LE by the operator more than is necessary. 
   It should be noted that as for the springs  13  and  15  ( 15 ′) described in the above-described two embodiments, other deformable resilient members or pneumatic springs may be used. Still alternatively, it is possible to adopt a mechanism in which, instead of the spring  13 , a weight and a pulley are used to urge the shaft  12  upward (in the direction of arrow B). 
     FIG. 5  is a diagram explaining a third embodiment of the invention. Although in each of the above-described embodiments an arrangement is provided to attach the cup by a manual operation, this embodiment shows an example in which the cup is attached by the driving force of a motor. 
   In the same way as the first embodiment, the cup C is fitted to the fitting portion  9  supported by an arm  40 . Reference numeral  41  denotes a moving mechanism section and is constituted by a motor  42 , a ball screw  43  attached to a rotating shaft of the motor  42 , and the like. As the ball screw  43  is rotated, the arm  40  is moved vertically in the direction of the reference axis L. The driving of the motor  42  is controlled by a control unit  45 . Connected to the control unit  45  are an input unit  46  for inputting various conditions, a start switch  47  for starting the cup attachment, and a memory  48 . In the input unit  46 , the type (suction type, seal type, etc.) of the cup C is inputted. The reason for this is that the attaching force necessary for cup attachment differs depending on the type of cup C. Incidentally, if in addition to the type of cup C there are other conditions for changing the attaching force such as the material and shape of the cup, the material and shape of the lens LE, and the type of coating, these conditions are also inputted. 
   On the basis of the inputted condition, the control unit  45  reads out the motor driving condition (electric power to be supplied to the motor) registered in advance in the memory  48 , and drives the motor  42  to move the arm  40  downward (in the direction of arrow A) . When the motor  42  is driven, the control unit  45  detects the current flowing across the motor  42 , and when the detected value of the current has reached a current value set in advance on the basis of the input condition (i.e., when it is detected from the load current applied to the motor  42  that pressure greater than a predetermined pressure is applied to the lens LE), the motor  42  is reversely rotated to move the arm  40  upward (in the direction of arrow B). Consequently, the cup C can be attached without applying an attaching force tore than is necessary to the lens LE. 
   It should be noted that the attaching force may be changed by inputting a numerical value from the input unit  46 . In addition, the attaching portion  9  and the arm  40  may be provided with a spring and a mechanism for changing the spring force in the same way as the preceding embodiments. In this case, a photosensor for detecting the deformation of the spring is provided, and the control unit  45  stops the lowering of the arm  40  in accordance with this detected signal, thereby completing the cup attachment. 
   As described above, in accordance with the invention, it is possible to prevent an excess force (more than is necessary) from being applied to the subject lens, and to attach the cup to the lens with a stable force.