AN IMPROVED RATCHET CLUTCH
Year: 1877

page_text: LETTERS PATENT to John Clayton Mewburn, of 169, Fleet Street, in the
City of London, Patent Agent and Consulting Engineer, for the Invention
of "AN IMPROVED RATCHET CLUTCH." A communication from abroad by
Thomas Aldridge Weston, of Stamford, Connecticut, in the United States of
Amering
Scaled the 22nd September 1877, and dated the 28th March 1877.
PROVISIONAL SPECIFICATION left by the said John Clayton Mewburn at
the Office of the Commissioners of Patents on the 28th March 1877.
JOHN CLAYTON MEWBURN, of 169, Fleet Street, in the City of London, Patent
Agent and Consulting Engineer. "AN IMPROVED RATCHET CLUTCH." A communi-
cation from abroad by Thomas Aldridge Weston, of Stainford, Connecticut, in the
United States of America.
This Invention consists of an improved ratchet clutch, and by way of illustration
I will describe it as applied to a toothed pinion and shaft.
The pauls and ratchet teeth may be arranged differentially in regard to cach
other in the manner described and shewn in the Specification and Drawings of
Thomas Aldridge Weston's Letters Patent dated April 18th 1863, No. 974. I place
the pauls concentrically in the body of the pinion, but their outer or acting onds
instead of being wholly exposed and projected from their sockets when acting upon
the ratchet teeth of the ratchet wheel are according to the present Invention
guided or shrouded to their extremo ends, one half or so of their thickness only
being exposed to the action of the ratchet teeth, their other longitudinal half being
shrouded or sunk in the metal of the pinion. Such pauls can only be crushed or
sheared, but they cannot be bent transversely, as the strain upon them is similar to
that upon a key used to fasten a wheel or pulley to its shaft. I thus obtain greater
strength on the pauls of ratchet clutches without increasing their dimensions,
rendering them more effective for transmitting, arresting, or regulating motion, I
duplicate or repeat these improved pauls in concentric circles or sets to any desired
extent.
To obtain an extremely minuto sub-division of stops or engagements in the circle,
all the pauls of all the sets are arranged differentially, so as to act one by one upon

page_text: the corresponding teeth of the ratchet wheel. To obtain great strength all the
pauls may be arranged to act at once or to act in sets.
When it is required to separate and disengage wholly the ratchet wheel from the
pauls, it may be withdrawn by a forked lever or any of the ordinary appliances for
releasing ordinary forked clutches.
Unlike a common forked clutch the improved ratchet clutch is capable of being
forced into gear instantly at any point on the revolution of its shaft.
The Invention is applicable to drilling braces, to watch keys, and stem winding
watches, and to any of the uses of ordinary ratchet wheels and clicks.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Clayton Mewburn in the Great Seal Patent Office on the
28th September 1877.
JOHN CLAYTON MEWBURN, of 169, Fleet Street, in the City of London, Patent
Agent and Consulting Engineer. "AN IMPROVED RATCHET CLUTCH." A. communi-
cation from abroad by Thomas Aldridge Weston, of Stamford, Connecticut, in the
United States of America.
This Invention consists of an improved ratchet clutch, and by way of illustration
I will describe it as applied to a toothed pinion and shaft.
The pauls and ratchet teeth may be arranged differentially in regard to each other
in the manner described and shewn in the Specification and Drawings of Thomas
Aldridge Weston's Letters Patent, dated April 18th 1863, No. 974. I place the
pauls concentrically in the body of the pinion, but their outer or acting ends instead
of being wholly exposed and projected from their sockets when acting upon the
ratchet teeth of the ratchet wheel are, according to the present Invention, guided
or shrouded to their extreme ends, one half or so of their thickness only being
exposed to the action of the ratchet teeth, their other longitudinal half being
shrouded or sunk in the metal of the pinion. Such pauls can only be crushed or
sheared, but they cannot be bent transversely, as the strain upon them is similar to
that upon a key used to fasten a wheel or pulley to its shaft. I thus obtain greater
strength in the pauls of ratchet clutches without increasing their dimensions,
rendering them more effective for transmitting, arresting, or regulating motion; I
duplicate or repeat these improved pauls in concentric circles or sets to any desired
extent.
To obtain an extremely minute sub-division of stops or engagements in the
circle, all the pauls of all the sets are arranged differentially, so as to act one by one
upon the corresponding teeth of the ratchet wheel. To obtain great strength all
the pauls may be arranged to act at once or to act in sets.
When it is required to separate and disengage wholly the ratchet wheel from the
pauls it may be withdrawn by a forked lever or any of the ordinary appliances for
releasing ordinary forked clutches.
Unlike a cominon forked clutch the improved ratchet clutch is capable of being
forced into gear instantly at any point on the revolution of its shaft.
The Invention is applicable to drilling braces, to watch keys, and stem winding
watches, and to any of the uses of ordinary ratchet wheels and clicks.
Having explained the nature of the Invention, I will proceed more particularly
to describe with reference to the accompanying Drawings the manner in which the
same is to be performed.
Figures 1 to 6 represent the Invention as applied to a toothed pinion and its shaft:
Figure 1 is an oblique perspective end view of the pinion and pauls, with the ratchet
wheel and shaft removed, and Figure 2 is a plan of the same; Figure 3 is a longi-
tudinal elevation, partly in section of the complete clutch; Figures 4 and 5 are
views of the ratchet whicel; Figure 6 represents one of the pauls detached.

page_text: Figures 7 and 8 shew my Invention applied to a winding key or ratchet wrench.
Similar letters of reference are affixed to corresponding parts in all the Figures.
A is a toothed pinion placed loosely on the shaft B between the fixed collar B¹
and the ratchet wheel C, which is secured by or slides upon the key or feather B³.
The pauls D are fitted to slide in suitable chambers arranged concentrically to the
shaft. The body or metal of the pinion forming the chambers for the pauls embraces
them up to their extreme ends, leaving a segment only of the paul exposed for the
action therein of the teeth C¹ of the ratchet wheel, the exposed portion of the pauls
appearing plainly in Figure 1, wherein the length of each paul projected from its
chamber is determined by the differential action thereon of the teeth of the ratchet
wheel. When thus arranged differentially the three pauls and four teeth yield
twelve points of interlocking or engagement in a revolution, but by employing three
teeth instead of four their collective strength is available for transmitting power
from the shaft to the pinion, or vice versa.
The ratchet wheel may be fixed to the shaft, when it will "slip" one way, and
"drive" the other, or it may be thrown into gear or withdrawn at pleasure by the
usual forked lever commonly used to operate "claw" or "ratchet clutches," or by
any suitable appliance always possessing this advantage of the present Invention over
the ordinary "claw" clutch, viz., that it can be thrown fully into gear by a single
positive movement at any moment irrespective of the relative position of the pauls
and teeth.
It is obvious that the pauls may be repeated in concentric circles or sets, and the
ratchet teeth be arranged in equal numbers to act all at once with all the pauls, or
differentially one by one or differentially in sets of two or more as may be desired.
Each paul has a spring E to hold it constantly up to the ratchet teeth, but when
placed vertically the gravity of the paul may make the spring needless; F is a pad
or buffer of felt or other yielding material to receive the blow of the paul as it shoots
over the point of a tooth; G is a flat or curved place cut in the paul which is
always in sliding contact with the rim surface C2 of the ratchet wheel from
which the teeth are projected, and thereby the pauls are held from turning on their
axes.
Figures 7 and 8 represent a winding key or ratchet wrench similar in con-
struction to the foregoing Figures, but of suitably small size, the shaft being at each
end formed into a pipe or square for engagement with the winding spindle of a clock
or watch, or for turning a screw nut, boring bit, or other like purpose, one end of
the shaft B yielding a right hand, and the other a left-hand motion. For the
purpose of winding a watch the small pinion teeth form a sufficient hold for the
thumb and finger. For drilling or like heavier uses the teeth are omitted, and a
radial lever may be attached wherewith to vibrate the paul cylinder A, and thus
impart an intermittent rotary motion to the shaft or spindle B in the usual manner
of working a ratchet brace or lever.
The Invention is applicable, whether the pauls slide in lines parallel to the shaft
as shewn in the accompanying Drawings, or at right angles thereto, as shewn in
Figures 8, 9, and 10 of the Drawings accompanying the Specification of Thomas
Aldridge Weston's Letters Patent dated April 27th 1866, No. 1196, and it is further
applicable to any of the purposes of ordinary ratchet wheels and detents.
Having now described the nature of the said Invention, and in what manner the
same is to be performed, I declare that I claim, the improved ratchet clutch herein-
before described and illustrated in the accompanying Drawings.
In witness whereof, I, the said John Clayton Mewburn, have hereunto set
my hand and seal, this Twenty-eighth day of September, One thousand eight
hundred and seventy-seven.
J. C. MEWBURN. (L.S.)