Tuesday, May 29, 2018

Super impact wrench

* My two most recent shade-tree projects presented me with a 27-mm harmonic-balance bolt and a 36-mm wheel-axle nut that wouldn’t respond to an impact wrench.  I managed to remove the harmonic-balance bolt with a 1/2"-drive breakdown socket wrench pulled at the 20" handle by a ratchet strap.  I managed to remove the wheel nut by use of  a large pipe wrench on a socket, the wrench's handle being extended by a 6-foot pipe (the breakdown wrench had snapped in an earlier attempt).
* All the while I was imagining and wishing for a new kind of impact wrench designed as shown in the following figures.
  *  The prospective device has two main parts: 1) a notched disk-shaped hammer component (diam ~ 8" - 10") cut from ~5/8" steel plate which spins on an axis counter-clockwise powered by an electric drill in reverse.
and 2) a wrench component cut from ~1/4" steel plate which transferes momentum from the hammer to a socket, via a square socket-drive bar (1/2" or 3/4") fused to a square hole at the wrench's axis.  The socket-drive bar extends through the wrench an inch on the opposite side, where it is rounded to a cylinder constituting the axis for the hammer to spin on.  The tip of this axis has a transverse hole with a pin to hold the hammer component (covered by a safety shield) flush against the wrench component.
The wrench component bears a spring-loaded catch which upon removal of a catch-retaining pin can jump into the path of the hammer's impact notch to receive the built-up angular momentum.  The wrench component's distal end is equipped with an eye to which a nylon rope is tied connecting it to a nearby stable object (eg car frame or suspension) to brake the excess angular momentum, so the device doesn't become a wild "battlebot" amputating the worker's extremities after loosening the nut or bolt.
The device is equipped with a safety shield covering the hammer to protect fingers from shearing between the hammer impact notch and the catch.  Its edge is rounded or beaded to avoid cuts.