US Patent 7758550 Injection device with a time-constant delivery signal

An injection device for administering a liquid product, the device including a drive mechanism, an engaging member and a catch including a number of latching elements, wherein at least one of the engaging member and the number of latching elements is relatively moveable to the other to generate a haptic and/or acoustic signal comprising a number of discrete signals during a relative movement, wherein one of the catch and the engaging member is coupled to the drive mechanism and the drive mechanism generates a variable drive speed during the relative movement, and wherein the latching elements are a distance (x0; x0-Δx) from each other such that a time interval between each of the number of discrete signals is constant. A method for generating a haptic and/or acoustic signal in use of an injection device is encompassed.