The Control Hammer

The device was invented to calibrate the Hipp Chronoscope along with the Gravity Chronometer and the Pendulum Chronometer.  It was designed to produce an absolutely accurate interval of time between opening its electrical contacts and closing them.

The control hammer apparatus consists of a bent lever whose arm is heavily weighted and turns about a horizontal axis. As the hammer-head descends, a cross bar on the shank makes or breaks the electrical contacts. An electromagnet releases the hammer and it falls past one electrical contact which opens the circuit to the Hipp Chronoscope, engaging its clutch and starting it measuring time. When the hammer falls past a second electrical contact, the circuit is closed, which makes the clutch on the Hipp Chronoscope disengaged and as a result stops its dial from moving. The control hammer is supposed to provide an absolutely reliable time interval which could be used to calibrate and check on the operation of the Hipp Chronoscope. The control time is varied by shifting the counterweight on the short arm of the lever.

The control hammer itself is needed to be calibrated. In order to know exactly how long the constant interval provided by the control hammer was, chronograph that accurately measures extremely small time intervals was needed.