A time clock, sometimes known as a clock card machine or punch clock or time recorder, is a mechanical (or electronic) timepiece used to assist in tracking the hours worked by an employee of a company.
In regard to mechanical time clocks this was accomplished by inserting a heavy paper card, called a time card, into a slot on the time clock. When the time card hit a contact at the rear of the slot, the machine would print day and time information (a timestamp) on the card.
One or more time cards could serve as a timesheet or provide the data to fill one. This allowed a timekeeper to have an official record of the hours an employee worked to calculate the pay owed an employee.