1. Field of the Invention
This invention generally relates to wristwatches, and in particular to a shock-resistant electronic wristwatch.
2. Prior Art
The more recently developed electronic watches, and those employing a digital display in particular, employ fragile components which are susceptible to damage from a mechanical shock. The integrated semiconductor chip or chips, which contain the time counting circuits, are themselves rugged and will withstand substantial shocks normally encountered. However, the complementary components of the digital watch module are more fragile. It is general practice in the digital watch art to mount the semiconductor chip or chips on a substrate, or disk-like printed circuit board, and to also mount the electro-optical display means on this same substrate. The substrate is usually mounted in a frame, which also supports a battery or batteries. Some prior art devices abut the batteries directly against the substrate, as shown in U.S. Pat. No. 3,838,568, which issued Oct. 1, 1974 to Zurcher, et al.
In such a prior art device, the batteries will crack the substrate or dislodge components mounted thereon when a substantial shock occurs such as, for example, dropping the watch. The mass of the batteries is substantially large in comparison to the other components in the watch, and thus have a large inertia. Therefore, dropping such a watch will create large mechanical momentum of the batteries, which can damage the watch module.
Another prior art device mechanically isolates the batteries from the substrate, and provides an independent electrical connection of the battery terminals to the substrate. An example of this prior art device is disclosed in U.S. Pat. No. 3,759,031, which issued Sept. 18, 1973 to McCullough, et al. This device overcomes some of the problems of the first-cited device in that the batteries are prevented from impacting directly against the substrate. However, this device does not completely overcome the problem of mechanically isolating the substrate from shock waves of the batteries created by, for example, dropping the watch.