How does does a tuning fork inside a hammer reduce vibrations? What are the benefits of reducing vibrations?
One benefit could be reducing fatigue and hand cramps. How? Beats me, man. I just use the things.
This appears to be a specially designed hammer to minimize vibration and to transfer maximum energy into driving the nail. There are also dead fall hammers which accomplish the same purpose by having a portion of the head filled with lead shot.
Apparently the tuning fork couples the vibration from hitting something into the handle in such a way that it isn’t transferred to the hand, wrist, elbow etc.
I’ve got to admit I’m a little uncertain since the tuning fork isn’t a lossy element. I’m unsure of why the tuning fork putting vibrations into the handle is any different from the hammer head putting vibrations into the handle.
I get a feeling that Stanley didn’t tell their trade secrets on the History Channel show I saw. The trick must be in how the tuning fork is attached to the handle.
You’re right - Stanley’s keeping mum about exactly how the AntiVibe hammer works. But in my googling, I found tesimonials (epinions, amazon user reviews, etc.) extolling the wonders of this tool, so evidently, it works well. I even found a medical supply / ergonomics outfit selling it.
My WAG is that the internal tuning fork converts the vibration of hammering into sound. It may be ultrasonic, or simply muffled by the grip, but it’s less net energy leaving the hammer through your arm - rather than changing how the impact is “coupled” it’s dumping the impact’s energy in the form of sound waves.
Oh, and dead-blow / dead-fall hammers (more often, they’re mallets and not nail-drivers) are an entirely different beast - the head is filled with sand or lead shot. On impact, the filling can move around a bit and minimize recoil.
Reducing recoil is not the same as reducing energy coming at your hand and arm through the handle. I’ve got one of these, and between weighing five pounds and the energy return, it’s not one I’d want to use all day long.
OK so it is different from a dead fall hammer. I had the priviledge to examine one today. The handle is longer that usual hammers. The shaft behind the head is thin and comparatively wide vertically compared to the thickness. I also has a crossection with the top and bottom edges thinner that the center. I would presume that the shape of the shaft and the material of the grip is what results in reduced vibration by cancelling out the normal ones.
Does it cotain a “Tuning Fork,” per se, not very likey, just a very well designed tool for critical craftsmen.
Sounds like the term “tuning fork” is being used because it makes good ad copy. They designed “tuned” the handle and its union with the head so as to rapidly rapidly damp out vibration at the gripping point. Maximizing such destructive interference is actually more of a detuning than a tuning, but calling the thing a detuned hammer just isn’t very sexy.
In the History Channel show on the Stanley anti-vibe hammer they showed an actual tuning fork being installed into a cavity in the handle. The hammer that spingears described is quite similar to the Estwing framing hammer.
This site describes the Stanley AntiVibe Hammer and contains the following:
“Stanley’s latest AntiVibe hammers still carry the patented tuning fork (and are supposed to reduce vibration three times better than the leading steel-handled competitor…”
The anti-vibe unit is described, sketchily, in the center column of the page.
Here’s an image from Stanley’s patent., and it is a sort of a tuning fork thingy.
The ibeam structure making up the handle is slit at the gripping end.
Hmmm. I couldn’t get either of the cites to show me a picture. The site came up with writing and stuff, but just a blank space where the drawing would be.
The USPTO uses Quicktime to show images. You may be able to access them elsewise through the patent texts:
6,202,511 (Mar, 2001)
6,370,986 (Apr, 2002)
Aha!
WThe patent reads in part:
“An end of the elongated support structure includes a pair of vibration-receiving portions terminating in spaced apart relation with respect to each other and spaced from each other in a direction parallel to a swing plane of the hammer. The manually engageable gripping portion [ED NOTE: in short, the handle or hand grip] is formed from a resiliently deformable material molded around a portion of the support structure** including the vibration-receiving portions so as to fill the space between the vibration-receiving portions.**[bold added]”
So it sounds as if the tuning fork or forks are excited by the dominent frequency of the hammet thereby transferring most of the vibration to the “deformable molded material” thus dissipating it into the grip rather than the hand and arm joints.
Having used both the Stanley antivibe, and Estwing hammers, I can’t notice any substantial difference in vibration transmission - which isn’t to say there isn’t any, just that I can’t notice it. For what it’s worth, I like the shape of the Stanley’s handle better, but prefer the Estwing’s claw. The latter preference outweighs the former.
That would be unnecessary. After all, a hammer is designed to “dump” a lot of its energy on the poor nail. 