Background Cardiac implantable electric devices are commonly used to treat heart failure. Little is known about temporal and geographic variation in use of cardiac resynchronization therapy (CRT) devices in usual care settings.
A hammer drill, also known as a rotary hammer, roto-drill or hammering drill, (see also rotary drill) is a rotary drill with a hammering action. The hammering action provides a short, rapid hammer thrust to pulverize relatively brittle material and provide quicker drilling with less effort.
A hammer crusher or hammer mill is a machine which crushes brittle materials such as limestone or coal, etc. through the use of high speed hammers.n American was responsible for the modern form of the claw hammer. In 1840, a Connecticut blacksmith, inspired by the adze, added a tapered neck that extended down the hammer handle, resulting in the so-called adze-eye hammer, which survives to this day.