 A clock is documented in this tower since 1405 , when a new bell was installed . The city accounts of 1438 mention the repair of the clockworks . The first mention of a dial is in 1443 , and the first known image of the , much smaller first astrolabium dial ( in the diary a cobbler journeyman from Ulm ) is dated 1534 . The jacquemart ( bellstriker ) is also documented in the same 1534 source . In the first two decades of the sixteenth century many craftsman unsuccessfully tried to improve the clockworks . The current movement was made in 1530 by clockmaker Kasper Bruner and is dated and signed by a forged nameplate . No other clockworks by this master are known . The core of the movement was forged in @-@ situ , in the very room it is still located , and the fire pit of the forge remains in the room . One of the more unusual features of the movement is that each individual tooth of the major gears is removable ( i.e.replaceable as it wears ) . Originally the movement had a verge escapement with a foliot , as it was built 127 years before the pendulum clock was invented . The Zytglogge movement was converted to a much more accurate pendulum mechanism by the French clockmaker Pierre Angely between 1686 and 1688 . The current pendulum bob , a " recycled " iron cannonball , possibly dates from that time . The pendulum suspension is made from leather rather than using a metal spring . The weight @-@ driven movement is wound daily by hand . That task , a role known as the " Zytgloggenrichter " , has been held for over 25 years by the same individual . 
