Preventing Injuries Due to Backfiring
Page 45
If you've noticed an error in this article please click here to report it so we can fix it.
ANEWdesign of safety-starting handle has recently made its appearance, it having been devised by Mr. A. C. Haworth, of Uplands, Moorside, Oldham, The principal components of the mechanism are shown in the accompanying illustration.
The operation of the handle is as follows: The spindle or shaft, with the usual connection to the crankshaft, passes through a stationary shell or bearing. In the outer end of the shell is bored a small hole to take the end of a coil spring. This spring, which surrounds a dogged sleeve, permits clockwise revolution of the sleeve which passes through it. Owing to the winding of the coils the spring tends to tighten upon the sleeve if anti-clockwise motion commences..
This means to say that the starting handle can be rotated only in a clockwise direction and carries with it the dogged sleeve. In the case of a backfire revolution of the starting handle becomes anti-clockwise. At once the spring grips the rotating sleeve and locks it. The sleeve can no longer turn with the handle and the inclined faces of the dogs force apart the two members, thus disconnecting the starting handle from the crankshaft.
It will be noticed that the amount of backward rotation experienced by the man turning the starting handle is that which occurs while the sleeve is being locked and that required to move endwise the handle shaft sufficiently to disengage the dogs.
Simplicity of construction is one of the main features of this design. The keynote of its satisfactory operation appears to be the ability of the coil spring to check the anticlockwise rotation of the dogged sleeve.