IMPROVED APPARATUS APPLICABLE FOR SHIFTING BELTS OR STRAPS IN MACHINERY
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by Wallace Cochrane Somerville at the
Office of the Commissioners of Patents on the 19th May 1876.
WALLACE COCHRANE SOMERVILLE, of Upper Thames Street, in the City of
London, Civil Engineer. "IMPROVED APPARATUS APPLICABLE FOR SHIFTING BELTS
OR STRAPS IN MACHINERY."
This Invention relates to improved apparatus applicable for shifting belts or
straps in all classes of machinery in or to which forward and reverse motions are
transmitted by such means.
The principle of the Invention consists in having the forks for actuating the
forward and reverse straps isolated from or completely independent of each other,
so that they may be actuated separately by suitable contrivances as desired, in lieu
of having them combined and working them together as heretofore.
The means or combinations of mechanical details which I employ for carrying
this principle out in practice are various in their kind, but they all have as their
common object the actuating of one fork at a time for the shifting of the required
belt from action, and the subsequent actuating of the other fork (if required) for the
shifting of the other belt into action.
The Invention it will be seen is chiefly applicable in or to machinery or appa-
ratus of all kinds, in or to which forward and reverse motions are communicated by
straight and crossed belts from one countershaft, through the medium of one or
more fast pullies on and to the shaft required to be actuated, the straps at other
times being shifted on to loose pullies carried also by the latter shaft on either sido
of the fast pulley or pullies. The Invention is also applicable to the working of
clutches.
In one modification of carrying this principle into practice I bolt a bar to the
side or other convenient part of the machine or apparatus, and in this bar longi-
tudinally I make a dovetailed slot, in which I set so as to be capable of sliding
therein the similarly shaped back pieces of the two movable or independent forks;
pins, or studs affixed to which back picces project forward of the face of the bar,
and in this modification constitute the medium through which the independent
motions are transmitted to the forks from a T lever centred in a frame carried
by the said bar, and provided at its cross end with a slot, in which the said pins or
studs engage, this slot being described from the centre of motion of the lever, and
terminating in directions radiating from the centre. The effect of this combination
is that upon the lever receiving motion one end of its slot actuates, say, the forward
Din 077

page_text: fork, and causes it to shift its belt from its loose to the fast pulley, while it allows
the reversing forks to remain over its loose pulley, upon reversing the motion of the
lever the forward fork is reshifted, and the reversing fork (if the motion of the lever
is continued far enough) is then shifted to the fast pulley.
Another modification consists in effecting these movements by a cam groove,
rack, and pinion.
By this Invention all the pullies are enabled to be of the same width, not
necessitating the use of wide loose pullies as hitherto.