Abstract:
An engraving dial formed of an upper dial plate, a lower dial plate, a bottom holder plate and a top holder plate for use in an inside ring engraving machine form is disclosed in which the upper dial plate and the lower dial plate are detachably and reversibly secured between the top and bottom holder plates, each dial plate having the top and bottom sides respectively engraved with a set of signs of a different form for selection.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an engraving dial formed of an upper dial plate and a lower dial plate for use in an inside ring engraving machine and, more particularly to such an engraving dial, which has the top and bottom sides of each dial plate respectively engraved with a respective set of signs for engraving selection. 
     2. Description of the Related Art 
     A ring is a circular band of precious metal, worn as an ornament. For memorial purpose, people may have the inside ring engraved with letters, numbers, symbols, etc., (hereinafter called signs). 
     A machine for engraving signs on the inside ring of a ring is called “inside ring engraving machine”. An inside ring engraving machine is used with an engraving dial to achieve the engraving. The invention pertains to an engraving dial for inside ring engraving machine. 
     FIGS. 1 and 2 show an engraving dial constructed according to the prior art. According to this design, the engraving dial, referenced by  70 , comprises a lower dial plate  71 , a hub  72  locked to the lower dial plate  71  at the top, and an upper dial plate  73  rotatably mounted on the hub  72  and supported on the top side of the lower dial plate  71 . The dial plates  71  and  73  have engraved signs  74  or  75  at the top. The lower dial plate  71  has V-notches  76  equiangularly spaced around the periphery. 
     When engraving words, for example, “My” on the inside ring and assuming that the initial “M” is at the lower dial plate  71  and the last letter “y” is at the upper dial plate  73 , thus the engraving operation is as follows: 
     At first, as shown in FIG. 3, the engraving dial  70  is installed in the base  61  of the inside ring engraving machine  6 , and then the engraving dial  70  is rotated to let the stopper  62  engage the V-notch  76  corresponding to the sign “M”, holding the lower dial plate  73  in the engraving position. Thereafter, fasten up the tightening knob  63  to lock the engraving dial  70  to the base  61  of the inside ring engraving machine  6 . Thus the user can operate the inside ring engraving machine to move the tracing stylus shaft  64  on the letter “M”, causing the diamond engraving cutter (not shown) to engrave the inside ring of the loaded ring. 
     When engraving the letter “y”, as shown in FIG. 4, rotate the upper dial plate  73 , for enabling the steel balls  79  of the locators  78  to be respectively forced by the respective compression springs  80  into the recessed round holes  81  at the lower dial plate  71  (See FIG.  2 ). Upon engagement of the steel balls  79  into the recessed round holes  81  of the lower dial plate  71 , a positioning click sound is produced, and the upper dial plate  73  is locked to the lower dial plate  71 . At this time, the signs  75  at the upper dial plate  71  and the signs  74  at the lower dial plate  71  are respectively aligned. Thereafter, fasten up the hold down bolt  82  to lock the upper dial plate  73  to the lower dial plate  71 , and then rotate the engraving dial  70  to let the stopper  62  engage the V-notch corresponding to the sign “y” at the upper dial plate  73 , and then fasten up the tightening knob  63  to lock the engraving dial  70  to the base  61  of the inside ring engraving machine  6 . Thus, the user can then engrave the sign “y” on the inside ring of the loaded ring. 
     This design of engraving dial provides only one combination of signs, for example, the combination of full cap signs at the lower dial plate and minuscule signs at the upper dial plate. Further, because one dial plate provides only one form of signs, the user may have to prepare additional dial plates of different forms of signs for selection. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished under the circumstances in view. 
     It is the main object of the present invention to provide an engraving dial, which has the top and bottom sides of each dial plate respectively engraved with a respective set of signs, providing four combinations for engraving selection. 
     To achieve this and other objects of the present invention, the engraving dial comprises a bottom holder plate, the bottom holder plate comprising an upper part, a lower part, the lower part of the bottom holder plate having an outer greater than the upper part of the bottom holder plate, a center through hole through the lower part and upper part of the bottom holder plate, and a plurality of screw holes extended through the lower part of the bottom holder plate and equiangularly spaced around the center through hole of the bottom holder plate; a lower dial plate, the lower dial plate comprising a center through hole adapted to accommodate the lower part of the bottom holder plate, a plurality of peripheral notches equiangularly spaced around the periphery thereof, two sets of signs respectively engraved on top and bottom sides thereof at imaginary radial lines between the center through hole of the lower dial plate and the peripheral notches, a plurality of recessed round holes symmetrically formed at the top and bottom sides and equiangularly spaced around the center through hole of the lower dial plate at an imaginary circle concentric to the center through hole of the lower dial plate; an upper dial plate, the upper dial plate comprising a center through hole, a peripheral opening, two sets of signs respectively engraved on top and bottom sides thereof corresponding to the signs at the lower dial plate; a top holder plate, the top holder plate comprising an upper part, a lower part fitted into the center through hole of the upper dial plate, the lower part of the top holder plate having a diameter smaller than the upper part of the top holder plate, a center through hole adapted to accommodate the upper part of the bottom holder plate, and a plurality of countersunk holes respectively fastened to the screw holes of the bottom holder plate by screws; and at least one locator, the at least one locator each comprising a retaining member respectively fastened to and vertically extended through the top holder plate, the retaining member having a bottom mounting hole, a compression spring mounted in the bottom mounting hole of the retaining member, and a steel ball supported on the compression spring at a bottom side and forced by the compression spring to selectively engage the recessed round holes of the lower dial plate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational view of an engraving dial for inside ring engraving machine according to the prior art. 
     FIG. 2 is a sectional view taken along line A—A of FIG.  1 . 
     FIG. 3 is an installed view of the prior art engraving dial in an inside ring engraving machine, showing the tracing of the tracing stylus shaft on the sign “M” at the lower dial plate. 
     FIG. 4 is similar to FIG. 3 but showing the tracing of the tracing stylus shaft on the sign “y” at the upper dial plate. 
     FIG. 5 is an elevational view of an engraving dial for inside ring engraving machine according to the present invention. 
     FIG. 6 is an exploded view of the engraving dial according to the present invention. 
     FIG. 7 is a sectional view taken along line B—B of FIG.  6 . 
     FIG. 8 is similar to FIG. 5 but showing the upper dial plate locked to the lower dial plate. 
     FIG. 9 is a sectional view taken along line C—C of FIG.  8 . 
     FIG. 10 is an installed view of the engraving dial in an inside ring engraving machine according to the present invention, showing the tracing of the tracing stylus shaft on the sign “M” at the lower dial plate. 
     FIG. 11 is similar to FIG. 10 but showing the tracing of the tracing stylus shaft on the sign “y” at the upper dial plate. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS.  5 ˜ 7 , an engraving dial  10  in accordance with the present invention is shown comprised of a bottom holder plate  1 , a lower dial plate  2 , an upper dial plate  3 , a top holder plate  4 , and two-locators  5 . 
     The bottom holder plate  1  comprises an upper part  11  and a lower part  12 . The outer diameter of the lower part  12  is greater than the upper part  11 . The lower part  12  has a flange  13  radially extended around the periphery thereof. The bottom holder plate  1  further comprises a center through hole  14  through which a dial tightening knob  63  is inserted to fix the engraving dial  10  to the base  61  of the inside ring engraving machine  6  (see FIG.  10 ), and a plurality of screw holes  15  extended through the lower part  12 . 
     The lower dial plate  2  is circular member stamped from a copper plate, having a center through hole  21  adapted to accommodate the lower part  12  of the bottom holder plate  1 , two annular grooves  22  symmetrically formed at the top and bottom sides around the center through hole  21 , a plurality of V-notches  23  equiangularly spaced around the periphery and adapted to receive the stopper  62  of the inside ring engraving machine  6  for enabling the lower dial plate  2  to be held in the engraving position, signs  24  symmetrically engraved on the top and bottom sides at the imaginary radial lines between the center through hole  21  and the V-notches  23 , a plurality of recessed round holes  25  symmetrically formed at the top and bottom sides and equiangularly spaced around the center through hole  21  at an imaginary circle  27  concentric to the center through hole  21 . The annular grooves  22  are adapted to receive the flange  13  of the bottom holder plate  1 , keeping the bottom holder plate  1  in flush with the bottom or top side of the lower dial plate  2  (see FIG.  7 ). 
     The upper dial plate  3  is a circular member stamped from a copper plate, having a center through hole  31 , a plurality of locating holes  32  equiangularly spaced around the center through hole  31  at an imaginary circle  35  concentric to the center through hole  31  and corresponding to the circle  27  at the lower dial plate  2 , and signs  34  symmetrically engraved on the top and bottom sides corresponding to the signs  24  at the lower dial plate  2 . The signs  34  at the upper dial plate  3  and the signs  24  at the lower dial plate  2  are of different forms and different sizes. The number of the locating holes  32  of the upper dial plate  3  is half of the number of the recessed round holes  25  of the lower dial plate  2 . 
     The upper dial plate  3  has a peripheral opening  33  through which the user can selectively see one or two signs  24  of the lower dial plate  2  while the other signs  24  of the lower dial plate  2  are blocked by the upper dial plate  3 . Further, supplementary signs  26  are symmetrically engraved on the top and bottom sides of lower dial plate  2  and respectively disposed adjacent to the V-notches  23 . The supplementary signs  26  are respectively indicative of the signs  24 . When the engraving dial  10  assembled and installed in the engraving machine  6 , the supplementary signs  26  are disposed outside the upper dial plate  3 . By means of the indication of the supplementary signs  26 , the user can quickly adjust the engraving dial  10  to move the assigned sign  24  to the engraving position. 
     The top holder plate  4  comprises an upper part  41  and a lower part  42 . The outer diameter of the upper part  41  is greater than the lower part  42 . The lower part  42  is fitted into the center through hole  31  of the upper dial plate  3 , keeping the bottom side of the top holder plate  4  in flush with the bottom side of the upper dial plate  3  (see FIG.  6 ). The top holder plate  4  has a center through hole  43  adapted to accommodate the upper part  11  of the bottom holder plate  1 , a plurality of countersunk holes  44  equiangularly spaced around the center through hole  43  and respectively fastened to the screw holes  15  of the bottom holder plate  1  by screws  46 , and a plurality of locating holes  45  located on an imaginary circle  40  concentric to the center through hole  43  and corresponding to the imaginary circle  27  at the lower dial plate  2 . 
     The locators  5  each comprise a retaining member  51  respectively press-fitted into the locating holes  45  of the top holder plate  4  and inserted into the locating holes  32  of the upper dial plate  3 . By means of moving the retaining members  51 , the upper dial plate  3  can be rotated to the desired angle. Because the retaining members  51  of the locators  5  are loosely inserted into the locating holes  32  of the upper dial plate  3  can easily be removed from the retaining members  51  for changing the position upside-down. The retaining member  51  of each locator  5  has a bottom mounting hole  52 , which accommodates a compression spring  53  and a steel ball  54 . The periphery of the bottom end of the bottom mounting hole  52  of the retaining member  51  of each locator  5  is hammered down to reduce the inner diameter of the bottom end of the bottom mounting hole  52 , preventing the steel ball  54  from falling down. The compression spring  53  imparts a downward pressure to the steel ball  54 , keeping the steel ball  54  in close contact with the surface of the top side of the lower dial plate  2  for enabling the steel ball  54  to be selectively engaged into one recessed round hole  25  of the lower dial plate  2  (see FIG. 8) to hold the upper dial plate  3  on the bottom dial plate  2  in position. 
     In order to prevent relative displacement between the dial plates  2  and  3 , the upper dial plate  4  is made having a screw hole  47 , which receives, a holding down bolt  48 , which has a bottom mounting hole  49 , which accommodates a pressure block  50 , which is molded from resin and partially protruding over the bottom side of the holding down bolt  48 . When rotating the holding down bolt  48  clockwise, the holding down bolt  48  is spirally moved downwards to lower the pressure block  50  and to force the pressure block  50  downwardly against the upper dial plate  3 , locking the upper dial plate  3  to the lower dial plate  2 . On the contrary, when rotating the holding down bolt  48  counter-clockwise, the pressure block  50  is released from the upper dial plate  3 , and therefore the upper dial plate  3  and the lower dial plate  2  are unlocked. 
     When engraving words, for example, “My” on the inside ring and assuming that the initial “M” is at the lower dial plate  2  and the last letter “y” is at the upper dial plate  3 , thus the engraving operation is as follows: 
     At first, as shown in FIG. 10, the engraving dial  10  is installed in the base  61  of the inside ring engraving machine  6 , and then the engraving dial  10  is rotated to let the stopper  62  engage the V-notch  23  corresponding to the sign (letter) “M”, holding the lower dial plate  2  in the engraving position. Thereafter, holding one retaining member  51  with the hand and moving it to rotate the upper dial plate  3  (at this time, the top holder plate  4  and the bottom holder plate  1  are rotated with the upper dial plate  3  relative to the lower dial plate  2 ), enabling the peripheral opening  33  to be moved to above the sign (letter) “M”. And then, fastening up the tightening knob  63  to lock the engraving dial  10  to the base  61  of the inside ring engraving machine  6 , thus the user can operate the inside ring engraving machine to move the tracing stylus shaft  64  on the letter “M”, causing the diamond engraving cutter (not shown) to engrave the inside ring of the loaded ring. 
     When engraving the letter “y”, as shown in FIG. 11, loosen the tightening knob  63 , and then move one retaining member  51  to rotate the top holder plate  4 , the upper dial plate  3  and the bottom holder plate  1  relative to the upper dial plate  3 , for enabling the steel balls  54  of the locators  5  to be respectively engaged into the recessed round holes  25  of the lower dial plate  2 . Upon engagement of the steel balls  54  into the recessed round holes  25  of the lower dial plate  2 , a positioning click sound is produced (due to friction between the steel balls  54  and the peripheries of the recessed round holes  25 ), and the upper dial plate  3  is locked to the lower dial plate  2 . At this time, the signs  34  at the upper dial plate  3  and the signs  24  at the lower dial plate  2  are respectively aligned. Thereafter, rotate the engraving dial  10  to let the stopper  62  engage the V-notch  23  corresponding to the sign “y”, and then fasten up the tightening knob  63  to lock the engraving dial  10  to the base  61  of the inside ring engraving machine  6 . Thus, the user can then engrave the sign “y” on the inside ring of the loaded ring. 
     It is necessary to operate the inside ring engraving machine  6  before engraving the sign “y”, keeping a suitable distance between the sign “y” and the sign “M” (this distance is adjustable). Because the adjustment of such distance is of the known technique not within the scope of the present invention, no further detailed description in this regard is necessary. 
     When using the signs at the bottom side of the lower dial plate  2  the bottom side of the upper dial plate  3 , the tightening knob  46  is removed from the base  61  of the inside ring engraving machine  6 , and then the top holder plate  4  is separated from the bottom holder plate  1 , and then the upper dial plate  3  and the lower dial plate  2  are taken away from the holder plates  1  and  4  and turned upside-down, and then the dial plates  2  and  3  are reloaded and locked. 
     As indicated above, the upper dial plate  3  and the lower dial plate  2  each have two sets of signs respectively engraved on the respective top and bottom sides, therefore there are total four combinations of signs for selection, i.e., the first combination includes the signs at the top side of the upper dial plate and the signs at the top side of the lower dial plate; the second combination includes the signs at the top side of the lower dial plate and the signs at the bottom side of the upper dial plate; the third combination includes the signs at the bottom side of the lower dial plate and the signs at the top side of the upper dial plate; the fourth combination includes the signs at the bottom side of the lower dial plate and the signs at the bottom side of the upper dial plate. 
     A prototype of engraving dial for inside ring engraving machine has been constructed with the features of FIGS.  5 ˜ 11 . The engraving dial for inside ring engraving machine functions smoothly to provide all of the features discussed earlier. 
     Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.