Abstract:
An alarm electronic timepiece has a base member, an alarm indicator wheel supported on the base member for rotation, an an indicating member integrally connected to the alarm indicator wheel for rotation therewith to indicate alarm time. A spring member supports the alarm indicator wheel on the base member and regulates a rotation direction of the alarm indicator wheel. The spring member is integrally connected to the base member.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an alarm electronic timepiece having an alarm indicator wheel holding structure. 
     In a conventional alarm indicator wheel holding structure, as shown in FIG. 5, a regulating face  21   a  of an alarm indicator spring  21  is pressed against a tooth form  20   a  of an alarm indicator wheel  20  by the spring force of the alarm indicator spring  21 , which is a spring member with a shape for regulating the tooth form of the alarm indicator wheel  20 , by which the positioning in the rotation direction is done. 
     The conventional alarm indicator wheel holding structure has the following problems: 
     (1) The regulating force cannot be made higher than the strength of tooth form because the tooth form of the alarm indicator wheel is regulated by a spring member. 
     (2) The regulating force for the alarm indicator wheel has a limitation, and the primary moment of an alarm hand is limited for the prevention of false indications caused by a shock due to dropping etc., so that a hand with an easy-to-see shape cannot be installed. 
     (3) When the tooth form of the alarm indicator wheel is regulated, the minimum setting unit of the alarm is limited. 
     SUMMARY OF THE INVENTION 
     The present invention provides an alarm electronic timepiece in which the alarm indicator wheel structure is simple and easy to assemble, and moreover, an alarm indicator wheel rotational position shift preventing means, which produces a large regulating force, is provided. Thus, by producing a large regulating force on an alarm indicator wheel, the critical primary moment of an alarm hand can be enlarged, and an alarm hand of an easy-to-see size can be installed, by which a hand shape of an excellent design can be provided. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a sectional view of an alarm indicator wheel holding structure for an alarm electronic timepiece in accordance with the present invention. 
     FIG. 2 is a plan view of an alarm indicator wheel for an alarm electronic timepiece in accordance with the present invention. 
     FIG. 3 is a sectional view of an alarm indicator wheel for an alarm electronic timepiece in accordance with the present invention. 
     FIG. 4 is a plan view of an alarm indicator wheel having an alarm indicator spring with a different shape for an alarm electronic timepiece in accordance with the present invention. 
     FIG. 5 is a plan view of a conventional alarm indicator wheel positioning structure. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the alarm hand holding structure in accordance with the present invention, an alarm indicator wheel is arranged at the outer periphery of an hour wheel, which is carried by a center pipe driven in a main plate, on the dial side of movement, the alarm indicator wheel is supported by a spring member, and the alarm indicator wheel rotational position shift preventing means is provided. 
     The aforesaid alarm indicator wheel rotational position shift preventing means supports the alarm indicator wheel and regulates the rotation thereof by two leaf springs in contact with the side face of the alarm indicator wheel with a spring force. 
     Also, a window is formed in the leaf spring, a portion at which the leaf spring slides is provided at the outer periphery of the alarm indicator wheel, and the leaf spring is installed so that the window of the leaf spring is in contact. 
     Embodiments will be described with reference to the accompanying drawings. FIG. 1 is a sectional view of an alarm indicator wheel holding structure for an alarm electronic timepiece in accordance with one embodiment of the present invention. FIG. 2 is a plan view of an alarm indicator wheel for an alarm electronic timepiece in accordance with the present invention. FIG. 3 is a sectional view of an attaching portion of the alarm indicator wheel and alarm indicator spring for an alarm electronic timepiece in accordance with the present invention. FIG. 4 is a plan view of an alarm indicator wheel having an alarm indicator wheel with a different shape for an alarm electronic timepiece in accordance with the present invention. 
     In FIGS. 1 and 2, reference numeral  1  denotes an alarm indicator wheel provided with an alarm hand  12 , and  2  denotes an hour wheel to which a driving force is transmitted from a not illustrated back wheel. Reference numeral  3  denotes a main plate through which a center pipe  3   a  for guiding the hour wheel is driven. Reference numeral  4  denotes a spring memmber (hereinafter referred to as alarm indicator spring)for supporting a sliding portion la of the alarm indicator wheel  1 . Reference numeral  5  denotes an alarm wheel for setting the operation of alarm contact and alarm time. Reference numeral  6  denotes an alarm indicator driving wheel, and  7  denotes an alarm setting wheel for transmitting a rotational force to the alarm wheel  5  when alarm time is corrected. Reference numeral  8  denotes an alarm clutch wheel, and  9  denotes an alarm winding stem. The alarm clutch wheel  8  is rotated by the rotation of the alarm winding stem  9  because a corner portion  9   a  of the alarm winding stem and a corner portion  9   a  of the alarm clutch wheel are engaged with each other. Since the alarm clutch wheel  8  engages with the alarm setting wheel  7 , a rotational force is transmitted to the alarm indicator driving wheel  6 , and the alarm wheel  5  is rotated, by which alarm time is set. The alarm indicator wheel  1 , which engages with the alarm wheel  5 , indicates alarm time on the face of a dial  11  by means of the alarm hand  12 . The alarm indicator spring  4  is positioned by engaging pins  3   a  and  3   b  provided on the main plate  3  with holes  4   b  and  4   c  of the alarm indicator spring  4 . The hole  4   b  formed at one end of the alarm indicator spring  4  is a round hole, and the hole  4   c  formed on the other end is an elongated hole. This configuration is used to overcome the difficulty in assembling the alarm indicator wheel  1  with the alarm indicator spring  4 , which is caused by the shift of a center distance of the holes  4   b  and  4   c  of the alarm indicator spring and the pins  3   a  and  3   b  provided on the main plate. The alarm indicator wheel  1  is supported in the crosssectional direction by being pressed slidably by a support for dial side parts  10 , which is fixed to the main plate  3  by screwing etc. The sliding portion  1   a  of the alarm indicator wheel provided at the end of the alarm indicator wheel  1  and an arcuate sliding portion  4   a  of the alarm indicator spring are in contact with each other by holding an elastic force, and the rotation direction of the alarm indicator wheel  1  is regulated by the elastic force caused by this contact. Also, the arcuate sliding portion  4   a  of the alarm indicator spring  4  is formed so that the contact portion engaging with the sliding portion  1   a  of the alarm indicator wheel  1  faces the intermediate portion of two bridge elements or portions  4   d  which connect with both ends of the alarm indicator spring  4 , by which a support is enabled by playing a role of the rotating shaft of the alarm indicator wheel  1 . Thereby, a clearance can be formed between the outer periphery of the hour wheel  2  and the inner periphery of the alarm indicator wheel  1 . Therefore, the alarm indicator wheel  1  can be rotated without the contact of the outer periphery of the hour wheel  2  with the inner periphery of the alarm indicator wheel  1 . When the arcuate sliding portion  4   a  of the alarm indicator spring  4  becomes eccentric, a shift of the rotating shaft of the alarm indicator wheel  1  occurs, but the inner periphery of the alarm indicator wheel  1  and the outer periphery of the hour wheel  2  do not come in contact with each other because of the clearance formed between the outer periphery of the hour wheel  2  and the inner periphery of the alarm indicator wheel  1 , so that a load is not given to the hour wheel  2 . Accordingly, the present invention is configured so that since a rotational load is not given to the wheel train connecting with the hour wheel, the operation of the hour indicating hand is not affected. 
     In FIG. 3, the end of the alarm indicator wheel  1  is provided with an alarm indicator spring attaching portion  1   a  of an inverse cone shape, which contacts with and slidably holds the arcuate sliding portion  4   a  of the alarm indicator spring  4  by an elastic force. To assemble the alarm indicator spring  4 , the arcuate sliding portion  4   a  of the alarm indicator spring  4  is pushed by being guided by a slant face portion  1   b  of the alarm indicator wheel  1 . The pushed alarm indicator spring  4  is integrally held so as to be slidable by the elastic force of two bridge portions  4   d  connecting with each end of the alarm indicator spring  4  and the alarm indicator spring attaching portion  1   a  of an inverse cone shape, which is provided at the end of the alarm indicator wheel  1 . 
     In an embodiment shown in FIG. 4, a spring portion of an alarm indicator spring  13  is formed in a cantilever shape and comprises a pair of arm portions  13   d , considering the assembling property of the alarm indicator spring  13 . For example, the alarm indicator wheel  1  is placed at a position indicated by the two-dot chain line, and is assembled by moving transversely until engaging with an arcuate sliding portion  13   a  of the alarm indicator spring  13 , which slides with the alarm indicator spring attaching portion  1   a  of an inverse cone shape, provided at the end of the alarm indicator wheel  1 . Thereby, the alarm indicator wheel  1  and the alarm indicator spring  13  are integrally held so as to be slidable. 
     When the alarm indicator wheel  1  with the alarm indicator spring  13  is assembled to the main plate  3 , it is positioned by engaging pins  3   a  and  3   b  provided on the main plate  3  with holes  13   b  and  13   c  in the alarm indicator spring  13 . 
     According to the present invention, in the alarm indicator wheel holding structure for an alarm electronic timepiece, since the alarm indicator wheel and the spring member for regulating the rotational position are integrated with each other, not only the alarm indicator wheel can easily be assembled to the main plate as the alarm indicator wheel with the alarm indicator spring, but also an alarm indicator holding torque can be secured reliably and sufficiently. Therefore, the primary moment of the alarm hand can be enlarged, and an easy-to-see hand shape can be provided.