Masonry Magazine August 2006 Page. 30
D・R・I・L・LS
have greater impact force per blow, lower frequency of blows per minute, and more comfort for the operator. This is better for drilling into concrete, but suitable in masonry.
The Li-lon roars
Everyone seems to agree that lithium ion (Li-Ion) is the battery chemistry of the present and future. Chetelat explained, "With Cordless Power Care (CPC) lithium ion, masonry professionals benefit from double the run time of NiCad batteries and get lighter weight. Hilti has individual cell management for longer lasting batteries and robust battery cells for better performance. There is also a 'state of charge' displayed on the battery so you know how much power you have at any time as well as drop resistant casings to help protect your batteries in job site conditions. The CPC lithium ion batteries allow masonry contractors to get more work per charge of the TE 6A Li for less weight versus a 24-volt tool. With the SFH 151 three-speed cordless hammer drill/driver, for example, a tool that has 35,000 beats per minute, masonry contractors can drill holes for concrete screws, like running a knife through butter. The SFH 151 is great for the many smaller diameter fastening applications that masons encounter."
Indeed, the Li-Ion battery technology leads the list of advances that make cordless a prime-time attraction. In some cases, this technology has allowed companies to introduce
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cordless units they didn't have before. One is Makita of La Mirada, Calif. "We have a hammer driver drill, which is good for light masonry work," acknowledged Bradley Wheeler, senior product marketing manager for cordless tools at Makita. "We also have a rotary hammer that we're going to launch in the summer of 2006. This is made practical by the lighter weight of the lithium ion battery."
Some cordless rotary hammers are heavy and, since a lot of this work is done overhead, the first advantage of lithium in this application is the lighter weight. "You also have the opportunity to pack in a few more amp hours 3.0 amps in our case," claimed Wheeler. "It has all the advantages or our corded tool in terms of the clutch that kicks in to protect against over-torquing. It's a three-mode hammer: hammer, hammer drill and drill. It has a variety of things that you don't see on a cord less tool right now."
Lithium ion has some major advantages over both NiCad and NiMH; 40 percent less weight than NiMH and 33 percent lighter than NiCad means that tool can be made more powerful at the same weight level of today's tools. "Li-Ion is 90 to 95 percent efficient in giving up it's energy, where NiCad and NiMH are 75 percent efficient," Tuerk noted. "That gives Li-Ion a huge advantage in running longer. Other advantages of Li-Ion are its ability to absorb energy very quickly in the charging process and the lack of a 'memory effect. A Li-Ion battery can be put into the charger at any point in its discharge cycle, with no harm to the battery. It also can be taken out of the charger at any point in the charging cycle, again, with no harm to the battery. A Li-Ion battery will retain a charge for up to 18