IMPROVEMENTS IN SCREW WRENCHES
Year: 1876

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS IN
SCREW WRENCHES." A communication from abroad by Otis Thomas Bedell,
of the City, County, and State of New York, United States of America.
Sealed the 11th August 1876, and dated the 15th March 1876.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 15th March 1876.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN SCREW WRENCHES."
This Invention relates to certain improvements in screw wrenches, whereby the
movable jaw may be quickly and readily adjusted to different sized nuts or bolt
heads with a very slight application of power, and it consists in a movable jaw
formed without a female screw thread, and sliding freely on the operating screw,
being provided with a spring of just sufficient stiffness to hold it in position when
no resistance is brought to bear upon it, combined with an independent nut or
carriage travelling upon the screw, and bearing against the movable jaw for the
purpose of holding it in position when pressure is brought to bear upon it, said
carriage being in lieu of the female thread in the movable jaw.
The Invention also consists in a bar having an angular back and a concave front
edge, and a movable jaw having a tubular portion adapted to the concave front edge
of said bar, and an angular keeper adapted to the angular back edge of the bar,
whereby the jaw is provided with a firm and steady bearing on the bar, as herein-
after described.
The movable jaw is made in the usual form, except that it has only one keeper,
and there is no female screw thread in the bore in which the screw works, in
consequence of which said movable jaw may readily slide on the bar independently
of the screw which is arranged and operates at the front of the bar. Between the
bar and the keeper is inserted a spring, which is made of a flat piece of metal, and
is held in place by a screw, or may be by being bent up on each side.of the keeper,
or in any approved way. This spring is of just sufficient stiffness to overcome the
weight of the movable jaw, and hold it in position when no resistance is brought to
bear upon it.
The carriage consists of a block of metal with a female screw thread formed in it

page_text: for engaging with the operating screw, which is attached to the wrench in the
usual way, and provided with a milled head for turning it.
The carriage may be made in the form of a nut; or it may be of an inverted
U shape, so as to be dropped over the screw and held in place by a hinged rod; or
it may be made in two pieces hinged together and in place by a spring when
placed on the screw. The most convenient and preferable form, however, for a flat
bar is a circular block with a piece cut from one side, so as to form a plane surface
for engagement with the bar, but for a bar with the concave front it will be circular
or nearly so. When mado in these forms it is placed upon the screw before the
latter is inserted in the moveable jaw and secured in plače.
In the improved form of bar the back edge of the bar is of convex angular form
from the fixed jaw to the point where it joins the bandle, said convex angular
portion forming three sides of a hexagon. The front edge of the bar is also made
angular but concave, the bottom of the concave portion being rounded.
The movable jaw is formed with a keeper which surrounds the bar in the usual
mauner, and is of angular form, corresponding with the angular back edge of the
bar.
The bottom of the inner surface of the angular portion of the keeper is provided
with a groove for the reception of the friction spring, which bears against the bar
to hold the jaw in position when no pressure is brought to bear upon it by the nut
or carriage.
The tubular portion of the jaw is made without a screw thread, and is open at
the bottom to facilitate its attachment to the bar, and also to prevent friction
against the bottom of the concave angular portion of the bar. When the screw is
turned to the right or left the carriage travels upon it either towards or away from
the movable jaw, said carriage bearing against the bar and preventing the carriage
from turning. In using this wrench the movable jaw is adjusted to the nut, and
the screw is then turned until the carriage bears against the movable jaw. If the
space between the jaws is to be made less the movable jaw is pushed toward the
fixed one, and the screw is turned to the right until the carriage bears against the
jaw. If the space between the jaws is to be made greater the screw is turned to
the left, so as to move the carriage away from the movable jaw, which is then
pulled away from the fixed jaw to the required point, and the carriage moved
against it.
The movable jaw is held in any position in which it is placed by means of the
spring, the tension of which is just sufficient to sustain the weight of the jaw, and
at the same time allow it to be easily moved by the thumb and finger.
The wrench can be readily operated with one hand as the movable jaw is easily
moved on the bar, and the screw turned by the thumb, while the handle is grasped
by the fingers; it will therefore be found of invaluable service in positions where
the person using it can apply but one hand to the work. The jaw can be instantly
moved to the desired point, and the screw having only the weight of the carriage to
resist it requires but a slight application of power to manipulate it.
In consequence of the angular form of the convex back edge and concave front
edge of the bar, and the corresponding form of the keeper and tubular portion of
the movable jaw, the bearing is entirely upon said angular portions, and is more
effective than if the contiguous bearings were plane surfaces.
The head of the stationary jaw has the upper corner bevelled in order to allow
more freedom for turning the wronch in places where the space is limited.

page_text: abroad by Otis Thomas Bedell, of the City, County, and State of New York, United
States of America.
This Invention relates to certain improvements in screw wrenches, whereby the
movable jaw may be quickly and readily adjusted to different sized nuts or bolt
heads with a very slight application of power, and it consists in a movable jaw
formed without a female screw thread, and sliding freely on the operating screw,
being provided with a spring of just sufficient stiffness to hold it in position when
no resistance is brought to hear upon it, combined with an independent nut or
carriage traveling upon the screw, and bearing against the movable jaw for the
purpose of holding it in position when pressure is brought to bear upon it, said
carriage being in lieu of the female thread in the movable jaw.
The Invention also consists in a bar having an angular back and a concave front
edge, and a movable jaw having a tubular portion adapted to the concave front
edge of said bar, and an angular keeper adapted to the angular back edge of the
bar, whereby the jaw is provided with a firm and steady bearing on the bar, as
herein-after described.
In the accompanying Drawing Figure 1 is a side view, partly in section, of a
wrench embodying these improvements; Figure 2 is a transverse section taken on
the line, x, of Figure 1.
Figure 3 is a perspective view of the carriage.
Figure 4 is a longitudinal section of a modified arrangement comprising the
angular bar, and Figure 5 is a transverse section of Figure 4 on line z, z.
Similar letters of reference indicate corresponding parts.
The movable jaw B is made in the usual form, except that it has only one keeper,
and there is no female screw thread in the boro in which the screw works, in
consequence of which said movable jaw may readily slide on the bar a independently
of the screw, the screw being arranged and operating on the front of the bar, as
shown in the Drawings. Between the bar a and the keeper b is inserted a spring C,
which is made of a flat piece of metal, and is held in place by a screw, or may be
by being bent up on each side of the keeper, or by any approved means; but may
be attached in any approved way. This spring is of just sufficient stiffness to
overcome the weight of the movable jaw and hold it in position when no resistanco
is brought to bear upon it.
The carriage D consists of a block of metal with a female screw thread formed in
it for engagement with the screw E, which is attached to the wrench in the usual
way, and provided with a milled head e for turning it.
"
The carriage D may be made in the form of a nut; or it may be of an inverted
Ushape, so as to be dropped over the screw and held in place by a hinged rod; or
it may be made in two pieces hinged together and held in place by a spring when
placed on the screw. The most convenient and preferable form, however, for a flat
bar is that shown in the Drawing, being a circular block with a piece cut from one
side, so as to form a plane surface d for engagement with the bar a, but for a bar
with the concave point it will be circular or nearly so. When made in these forms
it is placed upon the screw before the latter is inserted in the movable jaw, and
secured in place.
In the improved form represented in Figures 4 and 5 the back edge of the baris
of convex angular form from the fixed jaw to the point where it joins the handle,
said convex angular portion forming three sides of a hexagon. The front edge of
the bar is also made angular, but concave, the bottom of the concave portion being
rounded.
The movable jaw is formed with a keeper which surrounds the bar in the usual
manner, and is of angular form, corresponding with the angular back edge of the
bar.
The bottom of the inner surface of the angular portion of the keeper is provided
with a groove for the reception of the friction spring which bears against the bar
to hold the jaw in position when no pressure is brought to bear upon it by the nut
or carriage.

page_text: The tubular portion of the jaw is made without a screw thread, and is open at
the bottom to facilitate its attachment to the bar, and also to prevent friction
against the bottom of the concave angular portion of the bar. When the screw is
turned to the right or left the carriage travels upon it either toward or away from
the movable jaw, said carriage bearing against the bar a, and preventing the
enrriage from turning. In using this wrench the movable jaw is adjusted to the
nut, and the screw is then turned until the carriage bears against the movable jaw.
If the space between the jaws is to be made less the movable jaw is pushed toward
the fixed one, and the screw is turned to the right until the carriage D bears
against the jaw B, as shown in Figure 1. If the space between the jaws is to be
made greater the screw is turned to the left, so as to move the carriage away from
the jaw B, which is then pulled away from the fixed. jaw to the required point, and
the carriage moved against it.
The movable jaw is held in any position in which it is placed by means of the
spring C, the tension of which is just sufficient to sustain the weight of the jaw, and
at the same time allow it to be easily moved by the thumb and finger.
The wrench can be readily operated with one hand as the jaw B is easily moved
on the bar a, and the screw turned by the thumb, while the handle is grasped by
the fingers; it will therefore be found of invaluable service in positions where the
person using it can apply but one hand to the work. The jaw can be instantly
moved to the desired point, and the screw having only the weight of the carriage to
resist it requires but a slight application of power to manipulate it.
In consequence of the angular form of the convex back edge and concave front
edge of the bar a, and the corresponding form of the keeper and tubular portion of
the movable jaw, the bearing is entirely upon said angular portions, and is more
effective than if the contiguous bearings were plane surfaces.
The head of the stationary jaw has the upper corner bevelled at F in order to
allow more freedom for turning the wrench in places where the space is limited.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the herein-
before in part recited Letters Patent is,-
1st. In a screw wrench the jaw B formed without a screw thread, so that it
may slide freely on the bar independent of the screw E, in combination with the
spring C for holding said jaw in position where no resistance is brought to bear
upon it and nut or carriage D, substantially as described for the object specified.
2nd. The combination of the bar a, having the angular back edge and concave
front edge, with the movable jaw B, having the tubular portion adapted to the said
concave edge of the bar, and the angular keeper b adapted to the angular edge of
the bar, as herein shown and described.
In witness whercof, I, the said Alexander Melville Clark, have hereunto set my
hand and seal, this Fifth day of September, in the year of our Lord One
thousand night hundand