Time ball at Sydney Observatory
Made by Maudslay, Sons & Field Ltd in London, England, 1858.
Summary
H10401
A yellow and black time ball made of cast iron, with a cyliner, piston, rack and pinion lifting mechanism, safety lock, electric motor and ball.
Observatory stock numbers 9 and 10.
Observatory stock numbers 9 and 10.
Production
The Time Ball consists of a cast iron cylinder, piston, rack and pinion lifting mechanism, safety lock, electric motor and ball. The cylinder is 30cm diameter and 3 m long. Approximately 7 liters of soapy water fills the bottom of the cylinder to act as a buffer for the piston. The piston is a 10cm thick block of rubber with a bleeder valve to adjust rate of descent. The rack extends from the piston to the Time Ball and is 7.5 meters long. A pinion engages into the rack by a slide gear, which enables the electric motor to raise the rack. A large hand wheel is also attached with a pawl gear to prevent back-slipping. The Time Ball is attached to the top of the rack and is raised 2.7 metres.
At 6 minutes to 1PM the pinion is engaged into the rack and the electric motor switched on. It takes approx 2 minutes and 50 seconds to raise the ball to the top of the mast. The safety lock is then engaged and the pinion is disengaged. At precisely 1PM a signal from the atomic clock disengages the safety lock, causing the Time Ball to drop. It drops approx 2 metres immediately and the back pressure in the cylinder causes it to drop the remaining distance at a slower rate.
Carey Ward 10.3.83
At 6 minutes to 1PM the pinion is engaged into the rack and the electric motor switched on. It takes approx 2 minutes and 50 seconds to raise the ball to the top of the mast. The safety lock is then engaged and the pinion is disengaged. At precisely 1PM a signal from the atomic clock disengages the safety lock, causing the Time Ball to drop. It drops approx 2 metres immediately and the back pressure in the cylinder causes it to drop the remaining distance at a slower rate.
Carey Ward 10.3.83
Maudslay, Sons & Field Ltd 1858
Cite this Object
Time ball at Sydney Observatory 2015, Museum of Applied Arts & Sciences, accessed 27 June 2017, <https://ma.as/232664>
{{cite web |url=https://ma.as/232664 |title=Time ball at Sydney Observatory |author=Museum of Applied Arts & Sciences |access-date=27 June 2017 |publisher=Museum of Applied Arts & Sciences, Australia}}
This object is currently on display at the Sydney Observatory.
Incomplete
This object record is currently incomplete. Other information may exist in a non-digital form. The Museum continues to update and add new research to collection records.