Tuesday, January 29, 2019
How Does a Saw's Electric Brake Work
Pro Tool Reviews: Tool manufacturers continue to add more safety and fatigue-reducing features on their products. Examples abound with auto lock-ons, auto lock-offs, blade guards, and shields—just to start. You may take one safety feature for granted simply because you can’t see it—an electric brake. On the best circular saws and many other saws, an electric brake marks a premium feature. This solitary feature has saved many a blade, wood floor, cord, or even a finger or toe! It’s easy for a scrap of wood or some obstruction to prevent the blade guard from falling back in place after a cut.
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5 comments:
I found this article super informative. I was always aware of the idea of circular saws, and a lot of benchtop shop saws like radial arms saws and miter saws, having electronic brakes, but have never thought about how they really work. That being said, I knew a lot more about this mechanism than I thought. During my entire time in middle and high school, I worked on and then eventually ran my school's robotics team. My junior year, the competition we competed in required you to be able to shoot balls. We built a fly wheel on our robot, which is essentially a pitching machine. An issue we ran into was at the very end of every round, we needed to stop the fly wheel and spin it in reverse to run a lift on the back of our robot. Time was of the essence in the last 30 second of the round, so, in order to cut time, we created an electronic brake using the same exact principles to slow the wheel down faster.
Safety, no matter where you are or what your are working on, is paramount! I never knew that many circular saws and angle grinders have an electric brake. However, this feature seems like a no-brainer to me now that I know about it. When making tool purchases in the future, I will definitely keep electronic brakes as an important feature to have on applicable hardware. Though the article does not go in depth about the actual mechanism, the description of using electricity to slow the tool down reminds me a concept related to chain motor hoists. Earlier this week, we learned about regenerative braking in Motor School. Regenerative braking occurs when using a chain motor hoist to lower a load, such that the motor spins in reverse. This causes it to act as a generator, feeding electricity into the system. The electricity partially re-engages the motor, thus slowing the load as it is lowered. I imagine that electric brakes work similarly from a mechanical perspective to regenerative brakes.
I am always curious to read about safety technologies, especially in shop tools, because, in a place where so many things can go wrong, it is critical that developments like these continue. In my high school, the students weren’t allowed to use any rotating saws, but the carps the school hired explained that many have mechanisms such as this that prevent the possibility of some major issues. In reading my peers comments, I realized that electronic breaks are relevant to far more than just tools. It is interesting how they have been able to reverse the electricity quickly enough to stop the blade faster than it traditionally would have. In reading the first part of the article, I did wonder about how much wear these electronic breaks can actually handle. In a later portion of the article they began to talk about it, but they didn’t actually answer that question. However, it is critical to remember that these kinds of defenses are a last resort mechanism. It is on the operator to always be handling the tool safely.
I think while electric brakes are a great addition to power tools and hand help power tools in general. I think there is always still room for improvement. Having an electric brake presents a lot of opportunity for tool safety expansion in my opinion. One of the things that this article didn’t talk about that I think is a really important innovation that is starting to make it into tools is the immediate electric break due to shock dropping. This kind of feature I have specifically seen in things such Boschs new power tools. It allows for tools such as grinders and jig saws that have locking power on features to shut off and brake as the tools is for example dropped on the floor. These tools become highly dangerous when loose and on especially when cordless. This kind of brake being attached to different features in the tools allows I think for an added another level of safety that I would definitely pay for in power tools that I purchased for myself.
I always admire how pro tools format their articles for an easy read while still conveying important information. I found this article really interesting because the electric brake in tools is not something I ever put much thought into. After reading the article, it makes sense how the concept works and the article brings up a good point about safety, it is always in the hand of the person using the tool. I can see positive and negative aspects of the electric brake. It is, without a doubt, a safer option than letting a blade spin until it stops on its own, but the article does mention that this system does have an aspect of wearing out thus letting the blade spin for longer before stopping. A negative aspect I can see is that if a tool is dangerous enough, then the brake should be able to stop the blade on a dime much like the saw stop feature in their table saws.
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