Escapement anchor has slanted pallets on the arms which alternately catch on the teeth of the escape wheel, receiving impulses. Mechanically its operation has similarities to the verge escapement, and it has two of the verge's disadvantages: (1) The pendulum is constantly being pushed by an escape wheel tooth throughout its cycle, and is never allowed to swing freely, which disturbs its isochronism, and (2) it is a "recoil" escapement; the anchor pushes the escape wheel backward during part of its cycle. This causes backlash, increased wear in the clock's gears, and inaccuracy. These problems were eliminated in the deadbeat escapement,
Escapement was unworkable. Arnold also designed a spring detent escapement but, with improved design, Earnshaw's version eventually prevailed as the basic idea underwent several minor modifications during the last decade of the 18th century. The final form appeared around 1800, and this design was used until mechanical chronometers became obsolete in the 1970s. The detent is a detached escapement; it allows the balance wheel to swing undisturbed during most of its cycle, except the brief impulse period, which is only given once per cycle (every other swing). Because the driving escape wheel tooth moves almost parallel to the pallet, the escapement