It is common in the attachment of such threaded fasteners that the fastener must first be fitted to a structure with mating thread, then rotated without substantial torque until the fastener and structure are substantially, but not fully attached, then further rotated with a much higher degree of torque until the fastener is fully attached to the structure. A reversal of this procedure would be followed for removal of such a fastener from such a structure.
For example, to attach a hexagonally shaped nut with single pitch threading to a mating threaded post of a certain length which projects above a surface, one would first fit the nut over the post so as to engage the threads, then one would rotate the nut one turn for each thread of the post until the nut comes to contact the surface, then one would use a hexagonal wrench to further rotate the nut until a sufficient degree of locking pressure has been obtained between the nut and the surface. Depending on the number of threads of the post, and the fit of the mating threads, it is often preferred to use a tool adapted for fast rotation of those turns not requiring the high torque of the wrench.
There are a number of existing tools so adapted, including the tool depicted in FIG. 16 which is adapted for high speed rotation of a fastener, but the torque available from such a tool is insufficient to fully engage the fastener, or to disengage a fastener which had been fully engaged. Use of this tool, therefore, is only beneficial for the high speed/low torque rotations of the fastener, and one must still use the wrench to provide the high torque final rotations.
There are a number of other existing tools which are intended to have both of the properties of high speed/low torque and low speed/high torque application, but those are either complicated and expensive to produce, such as those that use switchable gearing, or are adapted to compromise both functions to provide service somewhat less than desired in each case, such as the tool depicted in FIG. 17 which cannot provide the torque of a standard wrench or the speed of a speed handle.
One existing tool which can serve both functions of high torque/low speed and high speed/low torque is depicted in FIG. 18 and is comprised of two long perpendicular bars permanently attached at their midpoints. One of the bars which is coaxial with the fitting is intended to provide a rotational support during high speed rotation, and the other bar is intended to provide a means for applying force during high torque application. The most notable disadvantage to this tool is its size and shape which render it cumbersome and expensive to inventory, ship, and store.
In U.S. Pat. No. 4,334,445, timewell discloses a tool which includes a fitting and a single handle, connected to an intermediary member by two hinges. This tool is claimed to be adaptable into positions which allow both high torque operation, and high speed operation. However, this invention lacks a means to support the tool with hands at two separate locations, rendering the tool difficult and awkward to operate during some applications in the high speed condition, for instance those applications where the fitting cannot firmly engage the fastener such as the way a slotted screwdriver engages a slotted screw. Also, due to the amorphous relationship between the fitting and the handle of this tool caused by the use and location of the two hinges, it is not practical to use this tool in the high speed condition for applications where, in addition to the usual tangential force, the fitting must engaged the fastener with also an axial force, such as the way a screwdriver engages a mating screw.