IMPROVEMENTS IN THE METHOD OF REVOLVING OR SLEWING CRANES
Year: 1884

page_text: COMPLETE SPECIFICATION.
HENRY JAMES COLES, 89 Sumner St. Southwark in the County of Surrey,
Mechanical Engineer do hereby declare the nature of my invention for
IMPROVEMENTS IN THE METHOD OF REVOLVING OR SLEWING CRANES and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:
My invention relates to a new and improved method of revolving or slewing
those species of cranes in which an upper bed or frame has a rotary motion
relatively to a lower or non-rotating bed whereby while the crane is possessed of
extreme mobility of rotation the liability to breakage or damage to its gearing
arising from the shock of too suddenly starting, reversing or stopping its revolving
motion, is reduced to a minimum.
According to my invention I place between the before mentioned upper and
lower beds of a crane a live ring of any suitable construction but having attached
or cast to it a circular rack into which the slewing pinion of the crane gears,
therefore when the slewing pinion is made to revolve the live ring revolves also.
As the live ring is a frame fitted with rollers, and as these rollers rest on the
lower bed of the crane while the upper or revolving bed rests on top of the rollers
it will be seen that when the live ring is made to rotate, the rollers in it also
rotate by the friction of the surface of their underside on the lower bed of the
crane, and at the same time the upper or revolving bed rotates in consequence of
the friction between it and the upper surface of the rollers but as the rack by
which the live ring and consequently the upper bed of the crane is made to revolve
is attached to the live ring and not to any immobile part of the crane, if the
revolving motion is too suddenly started, reversed or stopped the transition from
rest to motion or vice versa will be only gradual owing to the live ring and its
rack being free to skid on the lower bed of the crane and thus the shock caused
by the suddenness of this transition, which were the rack fixed to either bed of
the crane would probably cause the destruction of the gearing, will either entirely
disappear or be so slight as to have no injurious effect.
To more fully explain my invention I subjoin the following drawings and
description Fig. (1) is an elevation shewing the application of my invention to a
steam crane Fig. (2) is a plan of a live ring with the rack cast on it Fig. (3) is
a sectional elevation of the ring with conical rollers.

page_text: In the drawings A is the upper or revolving bed, B the lower or non-revolving
bed, C the live ring, D the slewing pinion and E the teeth of the rack, F F¹ the
rollers of the live ring. In Fig. 1 part of the live ring is cut away to shew the
teeth of the rack E and the slewing pinion D gearing into them.
Although in the drawings the rack is shewn cast to the inner circumference of
the live ring I do not confine myself to this position or manner of attachment as
the rack may be secured in any suitable manner, or placed in any position on the
live ring such as inside or outside, vertically horizontally or diagonally, likewise
the number of rollers in the ring may be varied in number according to circum-
stances and may be parallel in form as shewn in Figs. (1 & 2) or coned to have
true rolling contact according to their relative diameter with regard to that of the
surfaces in contact with them as shewn in Fig. (3) or they may be any other taper
or wholly or partially rounded to any curve on their rolling surfaces.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
(1.) For the slewing or revolving motion of cranes the construction of a live
ring having a rack cast or attached to it substantially in the manner and for the
*purposes herein described.
(2.) The combination of a live ring having a rack cast or attached to it with the
upper and lower beds of a crane substantially in the manner and for the purposes
herein described.