From the early days of the concept of time recorders, there was a rush in the USA and Europe to patent new ideas, methods, and engineering modifications to existing inventions to profit from what was then a booming market. There were hundreds of patent applications by many inventors from around 1855 to the mid 1900s, with several inventors forming companies which succeeded in turning invention into profitable business. Many inventors patented their machines or ideas in several countries to prevent ‘copying’ abroad, and many copies of original ideas by other inventors were made with subtle modifications to gain and retain production rights. Plagiarism appears to have been rife, resulting in many lawsuits between companies and inventors. Patents were generally only valid for 20 years, so many manufacturers ‘copied’ rival designs once the original patent had expired. 

Patent documents give full technical details and drawings of the inventions, alongside an excellent insight to the inventors and their location at the time. Very old UK patent documents are kept by The British Library, but most UK patents from 1870 onwards have now been scanned and are available online from the European Patent Office and Espacenet, which also include some worldwide patents. Many US patent documents are also available online using the Google Patents search engine. Direct links to these and other useful sources are available via the Links & References page.

My personal view is that the most significant time recorder invention which resulted in a manufactured machine was the Rochester card recorder by Daniel M. Cooper in 1894. This style and method of worker time recording was copied and developed by every manufacturer and remained in use for nearly a century.