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.