IMPROVEMENTS IN MACHINERY FOR BURNISHING SCREW-HEADS AND SIMILAR ARTICLES
Year: 1879

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for the Invention of
"IMPROVEMENTS IN MACHINERY FOR BURNISHING SCREW-HEADS AND SIMILAR
ARTICLES." A communication from abroad by Charles Dake Rogers, of
Providence, Rhode Island, United States of America.
Sealed the 12th August 1879, and dated the 11th June 1879.
COMPLETE SPECIFICATION filed by the said William Robert Lake at the
Office of the Commissioners of Patents on the 11th June 1879.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN MACHINERY FOR BURNISHING
SCREW-HEADS AND SIMILAR ARTICLES." A communication from abroad by
Charles Dake Rogers, of Providence, Rhode Island, United States of America.
The chief purpose of the improved machinery hereinafter described is to burnish
the heads of round-headed screws, and the said Invention comprises the combination
of a revolving spindle adapted to receive and hold a screw with a burnishing tool
so arranged that it is capable of adapting itself to the contour of the heads of
screws held in said spindle, and performs the burnishing operation upon the entire
surface of said heads.
In the accompanying Drawing,―
Figure 1 is a plan of my improved machine, with the hopper removed and the
spindle in section.
Figure 2 is a side elevation of the said machine; and
Figure 3 is an end view of the same, with a portion of the frame broken away
to shew more clearly the working parts; and
Figure 4 is a horizontal section of the feeding device which conveys the screws
to the spindle.
Like letters indicate the same parts throughout the Drawing.
As shewn in Figures 2 and 3, A represents the hopper, in which are placed in a
mass the screws whose heads are to be burnished. This hopper is supplied with
ordinary well known mechanism for selecting the screws from the mass and delivering
them to a conveyor, as shewn at B, from which the said screws are supplied one by
Prine Bd1

page_text: one to a roulette recipient, as shewn at C. This recipient has upon its periphery a
series of grooves c for receiving the screws, which are carried by intermittent partial
revolutions of said recipient to a "spoon-feed," as shewn at D, the screws being
retained in the grooves until discharged therefrom by a semi-circular guard-plate,
as shewn at E (Figures 2 and 3). The office of the "spoon-feed" D is to convey
the screws from the roulette C into axial alignment with a holding spindle, as
shewn at F, in which they are seated and held by mechanism hereinafter
described.
As the said machine is organized, the revolution of the recipient C is dependant
upon the movements of the "spoon-feed" D, which is mounted upon an arm, as
shewn at F (Figures 2 and 3) pivoted to the frame. This arm is engaged by a
bell-crank lever F, which is operated by a cam, as shewn at G, on the shaft G', and
a reactionary spring, as shown at g, to produce a laterally reciprocating movement
of the feed D. Upon the spindle, which carries the roulette recipient C, is also
mounted a bell-crank-lever, as shewn at H, the short arm being forked, and the long
arm carrying a pawl upon its end. During the movement of the feed D towards
the recipient, the forked arm of the lever H is acted upon by a projection d on
said feed, causing the pawl to engage one of the grooves c, and partially rotate the
receipient C, thereby releasing a screw, which falls into a receptacle in said feed,
and is conveyed into axial alignment with the spindle F. The receptacle
in the feed D for receiving the screws has sides formed by two separable
hinged wings d, controlled by springs, as shewn in Figure 4, the inner surface of
the free end of each wing being rounded or bevelled and furnished with a semi-
circular opening to facilitate and allow of the outward passage of the screws.
For seating the screws in the spindle F, the foed D is supplied with a plunger, as
shewn at I (Figures 1 and 4), the said plunger being in engagement with an arm,
as shewn at J (Figure 1), which has a longitudinal reciprocating movement imparted
to it by a cam, as shown at K, and a spring, as shewn at h. The action of the cam
K causes the plunger to advance (its end coming in contact with the screw-head)
and push the screw longitudinally out of the feed D, and into the spindle F,
where it is griped directly under the head and held against rotation upon its own
axis.
As shewn in Figures 1 and 3, the griping spindle F is a split tube secured within
and to a tube F³, which is mounted in a cylindrical casing, as shewn at L, having
bearings in the frame of the machine. The diameter of the rear portion of the
tube F3 is reduced, producing a shoulder, as shewn at f', against which bears a
spiral spring m, the other end of said spring bearing on a sliding block M, to which
are pivotted toggle-levers, as shewn at N. These levers N are enclosed in a cylin-
drical sliding sleeve O, which is engaged by a forked arm P mounted on a stud, as
shewn at p, and controlled by a cam, as shown at Q, on the cam-shaft G. At the
proper time the cam Q causes the arm P and sleeve O to advance and straighten
the levers N, and this action through the block M and spring m advances the tube
F3, and produces an engagement between the shoulders f on the spindle F and the
conical end of the casing L. The end of the spindle is thus closed upon the screw
with sufficient force to hold it, as above specified. After the burnishing has been
completed the screws are released by a backward movement of the spindle, and are
expelled by a spring-plunger shewn at f2, Figure 1.
The machine, as thus far described, is not essentially different from screw machines
heretofore employed, which have combined therewith dressing-tools for shaving or
shaping the heads of screws; therefore no claim is made to the feeding devices,
griping spindle, or its mechanism.
The distinctive difference between the machine to which this Invention relates
and machines einploying dressing tools for shaving or shaping the heads of screws
consists in the employment in the general organization described of a tool for
burnishing the heads, the action of which in the combination is peculiar and
distinctive from the action of the head-dressing tools in the other machines
referred to.

page_text: Referring to Figures 1 and 3 of the Drawing, R represents the burnisher mounted
on an axle in the forked end of a radius arm S, which arm is pivotted to a carriage,
as shewn at T, so as to be capable of longitudinal and lateral movements on said
carriage. The pivotal pin S¹ passes through a slot in the carriage, and is seated
against a cushion-spring, shewn at 8' (Figure 1). Upon one side of the arm S is
an inclined planes (Figure 1), and when the burnisher R is not in contact with the
head of a screw, the lateral position of the forward portion of the aria S relatively
to its carriage T is as shewn in Figure 1, the foot of the inclined plane & bearing
against a pin, as shewn at t, by the force of a spring 82, Figure 3, which exerts
pressure upon the arm S.
The burnisher R is brought into contact with a screw-head by the forward move-
ment of the carriage T, which movement is caused by the engagement of a cam U
(Figures 1 and 2) with a bell-crank lever V. The vertical arm of this lever sup-
ports and is hinged to the forward end of the carriage T, the rear portion of said
carriage being splined to a standard T¹ secured to the frame of the machine. The
retreat of the burnisher, after it has completed its work, is accomplished by a spring
S2 (Figure 1), which through an arms and link 84 (Figure 3) operates upon the
lever V, to move the carriage T and its burnisher into their rearward position.
That a new portion of the surface of the burnisher may be presented to each suc-
cessive screw, the spindle upon which it is mounted is provided with a ratchet W,
which ratchet is engaged by a stationary hook w (Figure 1) cach time the burnisher
moves forward, and it is thereby partially revolved.
The operation of those portions of the machine which act to convey the screws
from the hopper to the holding spindle, and clamp them therein, will be sufficiently
understood from the foregoing description, and will need no further explanation,
therefore I will now proceed to show the operation of the burnishing tool.
A screw being clamped in the holding-spindle F, the cam U acts upon the bell-
crank lever V and produces a forward movement of the carriage T, arm S, and
burnisher R, the burnisher being partially turned upon the axis during this move-
ment by the engagement of the hook w with the ratchet W. The forward movement
of the carriage T brings the burnisher in contact under a yielding pressure with the
edge of the screw-head, the axis of the arm S being perpendicular to that of the
screw, but farther longitudinal advancement is prevented by reason of the relative
position of these axes until the said burnisher is laterally moved. This is accom-
plished by the engagement of the pin t upon the moving carriage, with the inclined
plane & on the arm S. This pin, during the continued advancement of the carriage
T, moves over the inclined plane 8, and causes a lateral movement of the burnisher
until it has arrived at such a portion of the screw-head that the contour of said
head will alone serve to complete the lateral movement.
During the remaining portion of the forward movement of the burnisher, and
during such portion of the retreat as is necessary to bring it back to the position
specified, the contour of the screw-head wholly governs the lateral movements of
the burnisher, the longitudinal movements being produced by the cam U and spring
S, and the burnisher being held up to its work by the spring s².
It will be seen from the foregoing description that the burnishing tool is capable
of yielding, to enable it to conform its path of movement to the particular shape of
the half round or other formed head to be burnished, and that the licad itself performs
an office in giving direction to the path of movement of the tool; whereas in
machines employing dressing tools for shaving or shaping the heads of screws or
similar articles, the tool has a positive movement given to it, which is unaffected by
the particular shape of the head operated upon. Again, the feature of construction
which provides for inaking the burnishing tool capable of revolving intermittingly
upon its axis upon each backward and forward movement of the carriage upon
which it is mounted is important in machines which may give a positive movement
to the burnisher, and dispense with the means which in the said improved machine
enables it to yield to the particular shape of the head.
Having thus fully described the said Invention as communicated to me by my

page_text: foreign correspondent, and the manner of performing the same, I wish it understood
that I claim,―
First. The combination of a revolving spindle capable of holding a screw or other
article, the head of which is to be burnished, and a burnishing tool held to its work
by spring pressure, and moved by suitable means in the plane of the longitudinal
axis of the revolving spindle, the said burnishing tool as it advances having a hori-
zontally lateral movement modified by the shape of the head to be burnished,
substantially as described.
Second. The combination of a revolving spindle capable of holding a screw or
other article whose head is to bo burnished, a burnishing tool which has the proper
movements given to it by suitable mechanism for enabling it to exert pressure upon
such head, and a pawl and ratchet or equivalent means for intermittingly revolving
the burnisher to present a fresh section of its surface to each successive head,
substantially as above set forth.
Third. The combination of a revolving spindle and a yielding burnisher mounted
upon a radius arm pivotted to a carriage, which has a movement given to it in a
direction radial to the axis of the revolving spindle by suitable mechanism, the
said radius arm as it is advanced by the carriage receiving a horizontally lateral
movement, to enable the burnisher to conform to the shape of the head to be
burnished, substantially as herein set forth.
Fourth. The burnishing machine, consisting of the parts shewn in the accom-
panying Drawing, and constructed and arranged substantially as described, to operate
as and for the purposes specified.
In witness whereof, I, the said William Robert Lake, have hereunto set
my hand and seal, this Eleventh day of June, in the year of our Lord One
thousand eight hundred and seventy nine.