Patent Publication Number: US-4148183-A

Title: Supporting structure for quartz oscillator

Description:
This invention relates to electronic timepieces and, more particularly, to a structure for supporting a quartz oscillator in such timepieces. 
     In electronic timepieces equipped with a quartz oscillator having a pair of external terminals at one end, it has been a common practice to solder the terminals to a circuit substrate of the timepiece and then either employ a bonding process according to which the quartz oscillator is adhered to the circuit substrate, or a method which makes use of a metal leaf spring to secure the oscillator to the circuit substrate. However, both of these methods posesses certain disadvantages. The bonding method, for example, is time consuming and can not provide bonding reliability owing to the small size of the oscillator. On the other hand, the method which utilizes a spring requires too many components to mount the spring and the actual procedure is difficult. Furthermore, in view of the timepiece arrangement, there is no need for the circuit substrate to directly support the quartz oscillator; it is sufficient merely to electrically connect the oscillator terminals to the circuit substrate. 
     It is, therefore, an object of the present invention to provide a supporting structure for a quartz oscillator which is not beset by the aforementioned defects and yet which is readily assembled and capable of providing improved impact resistance. 
     It is another object of the present invention to provide a supporting structure for a quartz oscillator which is simple in construction and low in manufacturing cost. 
    
    
     These and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a plan view showing a first preferred embodiment of a supporting structure according to the present invention by which a quartz oscillator is assembled to a circuit substrate of an electronic timepiece; 
     FIG. 2 is a cross sectional view taken along line II--II of FIG. 1; 
     FIG. 3 is a plan view showing a second preferred embodiment of a supporting structure according to the present invention; 
     FIG. 4 is a cross sectional view taken on line IV--IV of FIG. 3; and 
     FIG. 5 is a cross sectional view taken on line V--V of FIG. 3. 
    
    
     Referring now to FIGS. 1 and 2, there is shown a portion of an electronic timepiece 10 in which a quartz oscillator 11 is mounted on a circuit substrate 12 by means of a supporting structure according to the present invention. The quartz oscillator 11 has a pair of terminal pins 11b extending from one end portion of the oscillator, which are pins connected to a wiring pattern provided on the circuit substrate 12 by some suitable means such as soldering. The supporting structure is composed of supporting or cushioning member 13 made of elastic material such as plastic. The supporting member 13 has a flat portion 13a sandwiched between the quartz oscillator 11 and the circuit substrate 12 supporting the one end portions of the oscillator, a vertical portion 13b projecting upwardly from the flat portion around the periphery thereof and fitting around an outer periphery of the oscillator, and at least one hook 13c extending vertically from the flat portion at a position away from the terminal pins 11b of the oscillator the one end portion of which is rigidly connected to and supported by the circuit substrate and engaging a flange 11a of the oscillator at another end portion thereof 11. The supporting member 13 also has a notch 13d formed in the flat portion 13a adjacent the terminal pins 11b so as to allow the removal of residual cleaning agent being used to clean the terminal pins following the soldering procedure. Indicated at 13e is a slot formed in the flat portion 13a adjacent the hooks 13c to provide a greater elasticity thereto. 
     According to the above mentioned construction, the quartz oscillator 11 is mounted on the circuit substrate 12 in such a manner as to hold the supporting member 13 therebetween. Thus, as can be appreciated from FIG. 2, a portion of the supporting member 13 is inserted and held between a lateral base extension of a base plate 14 for a timepiece and circuit substrate 12 and is accordingly perfectly secured since circuit substrate 12 is fixed to the base plate 14. In consequence, the oscillator 11 is fixed by the hook 13c of the supporting member 13 due to the fact that the supporting member is held between the base plate 14 and circuit substrate 12. Moreover, the supporting member can, instead of metal base plate 14, be held between a timepiece cover, bridge or case, and through the intermediary of a rigid bridge member. 
     Accordingly, when a timepiece is subjected to an impact, the quartz oscillator 11 sustains the impact through the intermediary of the oscillator supporting member 13 so that the impact is alleviated by the resiliency of the supporting member. In addition, assembly is a simple matter since only two hooks 13c are manipulated so as to merely engage the oscillator, an advantage that does away with the troublesome conventional bonding method. It is also possible to suitably position quartz oscillator 11 in a horizontal plane by appropriately positioning the supporting member with respect to other components and then securing it. This is another important advantage in view of the fact that it was hitherto necessary to provide a large amount of space around the quartz oscillator to prevent it from striking other components upon impact. 
     A second preferred embodiment of the present invention is illustrated in FIGS. 3 to 5. In FIGS. 3 to 5, timepiece circuit substrate 21 made of ceramic material or the like is composed of three overlapping layers 21a, 21b, 21c, and is provided with a circuit chip and a wired metalized pattern. Reference numeral 21d denotes a wiring pattern for connecting the circuit chip (not shown) to external terminal pins 22a of a quartz oscillator 22 which is supported by an end portion of the circuit substrate by means of terminal pins 22a connected thereto. As can be seen in the drawings, the quartz oscillator is an oblong structure with a pair of external terminal pins 22a provided at one end. Terminal pins 22a are soldered to pattern 21d on the circuit substrate 21 by means of solder 21e. Reference numeral 23 denotes a liquid crystal cell, reference numeral 24 a liquid crystal cell positioning member for levelling liquid crystal cell 23, and reference numeral 25 a supporting plate for supporting circuit substrate 21. In this illustrated embodiment, a quartz oscillator supporting member 26 is supported by the liquid crystal cell supporting member 24 and supporting plate 25 so as to be structurally positioned and retrained. The quartz oscillator supporting member 26 is secured between the quartz oscillator 22 and the circuit substrate 21 and is made of a shock absorbing material such as plastic which exhibits elasticity. The quartz oscillator supporting member 26 has a flat portion 26a composed of a first section 26&#39;a sandwiched between a bottom wall of the quartz oscillator and the end portion of the circuit substrate 21 and a second section 26&#34;a integral with the first section and engaging the bottom wall of the oscillator 22, a dowel 26h integral with the second section of the flat section 26a and sandwiched between the cell supporting member 24 and the supporting plate 25, a vertical projection 26b, vertically extending from the flat portion 26a and engaging an outer periphery of the oscillator 22, and at least one hook portion 26c extending from the second section of the flat portion 26a at a position away from the first section and retaining the flange 22b of the oscillator to support another end portion of the oscillator. The second section 26&#34;a of the flat portion 26 has a recess 26d, a thin wall portion 26e facing thereto, and a downward projection 26f integral with the thin wall portion 26e and engaging an upper surface of the supporting plate 25. The supporting member 26 is further provided with slots 26g adjacent the hooks 26c to provide an elasticity thereto as in the first embodiment. 
     The quartz oscillator 22 is positioned with respect to the circuit substrate 21 by the flange 26b of the quartz oscillator supporting member 26 and by the shape of the circuit substrate 21. When the circuit substrate 21 to which the quartz oscillator 22 is connected is installed in a timepiece, the circuit substrate 21 is supported by the supporting plate 25. In this case, the combination recess 26d, thin wall portion 26e and projection 26f compensate for the variations in thickness of the layers 21b and 21c of the substrate 21. As shown in FIG. 4, the supporting member 26 has a dowel 26h at one end, which is sandwiched between the crystal cell supporting member 24 and the quartz oscillator supporting member 26. 
     When the quartz oscillator 22 is subjected to an impact, the structure and composition of quartz oscillator supporting member 26 permit the impact to be absorbed so as to protect crystal oscillator 22. In view of design and the fact that the ceramic circuit substrate 21 is extremely fragile, far more impact resistance is obtained by employing the quartz oscillator supporting member 26, which is made of a shock-absorbing material, to support quartz oscillator 22 with respect to the circuit substrate 21. This is more preferable than extending and enlarging the circuit substrate below the oscillator and greatly simplifies assembly. Indicated as 26i is a slanted wall of the supporting member 26. 
     While the present invention has been shown and described with reference to particular embodiments, it should be noted that various other changes or modifications may be made without departing from the scope of the present invention.