A time measurement device includes: a higher-digit indication hand that is configured to indicate a higher digit of a measured time; a lower-digit indication hand that is configured to reciprocate and indicate a lower digit of the measured time on a forward route and on a return route; a first drive unit that is configured to drive the higher-digit indication hand; a second drive unit that is configured to drive the lower-digit indication hand; a time counter that is configured to measure a time; a first drive controller that is configured to control the first drive unit to drive the higher-digit indication hand based on the measured time measured by the time counter; and a second drive controller that is configured to control the second drive unit to drive the lower-digit indication hand based on the measured time measured by the time counter, the second drive controller reciprocating the lower-digit indication hand at a predetermined period, and the first drive controller moving the higher-digit indication hand at a time interval equal to or less than a half of the predetermined period.

The present application provides a timer, including a base, a driving shaft, and an indicator arm. The driving shaft is rotatably mounted on the base and selectably rotates relative to the base. The indicator arm includes a second support and a plurality of hour blocks. The second support is rotatably connected to the driving shaft. The hour blocks each include a second block body and a second gear. The second block body is rotatably connected to the second support. The second gear is fixedly connected to the second block body. Second protrusion is correspondingly arranged on a rotation path of the second gear around the driving shaft. The second gear has second tooth grooves. The second protrusion selectably extends into the second tooth grooves to drive the second gear to rotate relative to the second support so as to drive the hour blocks to rotate relative to the second support.

The present application provides a timer, including a base, a driving shaft, and an indicator arm. The driving shaft is rotatably mounted on the base and selectably rotates relative to the base. The indicator arm includes a second support and a plurality of hour blocks. The second support is rotatably connected to the driving shaft. The hour blocks each include a second block body and a second gear. The second block body is rotatably connected to the second support. The second gear is fixedly connected to the second block body. Second protrusion is correspondingly arranged on a rotation path of the second gear around the driving shaft. The second gear has second tooth grooves. The second protrusion selectably extends into the second tooth grooves to drive the second gear to rotate relative to the second support so as to drive the hour blocks to rotate relative to the second support.

A tachymeter device for indicating an average speed of a moving object and a wristwatch comprising such a tachymeter device comprise a timer and an activator for manually starting the timer, when the object passes a starting mark, and stopping the timer, when the object passes a defined distance from the starting mark. They further comprise a housing, a scale for indicating an average speed of the moving object and a pointer for indicating a measured average speed on the scale, wherein the measured average speed is derived from said defined distance and a time to cover said defined distance measured by the timer. The scale is designed as a scale part that is arranged detachably at the housing. The scale part is selected from a set of scales parts comprising a plurality of differing scale parts each having a scale with speed indication for indicating speed ranges corresponding to differing pre-defined distances.