Rotary hammers, also called "combi drills," are similar in that they also pound the drill bit in and out while it is spinning. However, they use a piston mechanism instead of a special clutch. This causes them to deliver a much more powerful hammer blow, making it possible to drill bigger holes much faster. Rotary hammers have such force, in fact, that the usual masonry bits are no longer adequate. Their smooth shanks would be pounded loose from the tool's chuck in a few seconds. Rotary hammers require special bits which lock into the rotary hammer and continue spinning while smashing away.
A number of "special shanks" have been developed by various manufacturers. Over the years a fair number of these proprietary systems evolved, but the remaining shanks in use today are: SDS+, SDS-MAX, and SPLINE SHANK. These shanks were developed in order to allow for the bit to "slide" back and forth while rotating, so that the drill bit can efficiently transfer the force of the electro-pneumatic hammering mechanism to the working surface.
Rotary hammer drills have an oil filled gearbox, which allows them to operate durably despite the large forces and shocks they receive and the grit-filled environments where they are often used.
NENZ Electric Technology Company has more than 20 years experience in production of multifunctional rotary hammer . It is a hightech enterprise professionally engaged in the R&D, production, sales, test and service of power tools. Located at the global most innovative and vigorous forefront region, Dongguan City of Guangdong Province. Owing to the international top level design and production, the product quality and property can meet the industrial users' strictest utilization requirements for tools under different kinds of harshly working environments.