After quoting statistics that show the alarming increase in thefts of automobiles and analyzing numerous conditions under which automobiles are stolen, the authors discuss locks as theft retardants, saying that the providing and the improvement of locks has always been man's method of seeking security from thieves and comes in naturally for first consideration as the normal course to pursue in working toward adequate theft prevention. The present identification systems in use are mentioned, together with their features of advantage and disadvantage, and numerous practices that owners and drivers can adopt which tend to minimize theft are cited. The early forms of locking device are outlined and statistics are included which show the percentage of cars actually locked when they are equipped with a locking device.
The coincidental lock was developed to take advantage of the fact that drivers almost universally turn off the ignition switch when leaving a car unattended, and because this is about the only operation that all drivers can be depended upon to perform. The coincidental lock seeks by one means or another to take the foregoing fact into account by making the locking and the ignition functions interrelated so that it is impossible to open the ignition-circuit switch without either previously or simultaneously locking the car. The standard classification of the Underwriters Laboratories with regard to locks is quoted and commented upon, and the objections to coincidental locks are analyzed.
Popular conceptions of car locking are stated and suggestions made regarding proper procedure for drivers. Desirable and undesirable lock characteristics are enumerated and a list is presented that includes 10 specific rules for judging the effectiveness of automobile locks. An illustrated description of the various types represented among the locks now classified as Group 1 is then presented to bring out the leading constructional and operative characteristics of coincidental locks.


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