Art of and Apparatus for Turning and Polishing Shafting.
Year: 1894

page_text: Date of Application, 13th Mar., 1894-Accepted, 21st Apr., 1894
COMPLETE SPECIFICATION.
Art of and Apparatus for Turning and Polishing Shafting.
PHILIP MEDART, Mechanical Engineer, a citizen of the United States, residing.
at No. 1729 Missouri Avenue, in the City of St. Louis, County of St. Louis, and
State of Missouri, U.S.A., and WILLIAM MEDART, Manufacturer, a citizen of
the United States, residing at Southern Hotel, in the City of St. Louis, County of
St. Louis, and State of Missouri, U.S.A., do hereby declare the nature of this
invention and in what manner the same is to be performed to be particularly.
described and ascertained in and by the following statement :-
This invention relates to the turning and polishing of round rods or shafting,
and its objects are simultaneously to remove the scale and outer coating or surfaces
of such shafts, thus reducing them to uniform dimensions, while producing a smooth
surface thereon, and to impart a finished appearance to the shafting by polishing its
surface.
•
These ends we attain by clamping or supporting the shafting in a suitable bed-
plate, and feeding the shaft end wise through revolving chasers and cutters, adjustable
radially, relatively to each other and to the shaft in the cutter-head, so as first to
form a screw-thread or series of screw threads on the shaft, by means of one set'
of chasers, by means of which threads the shaft is fed through the cutter-head,
and is simultaneously reduced; then further reducing the diameter of the shaft by
cutting off the apices or ridges of the threads formed by the preceding set of
chasers or cutters, and then turning down the shaft to the required dimensions by a
cutter or cutters, from which the shafting passes directly to suitable polishers,
which finish it. The cbasers are preferably made with two or more threads, so as
to secure rapidity of action, without undue increase of driving power, or heating
of the cutting tools.
The threads or teeth on the chasers are preferably arranged at such an angle or
pitch as to cut two or more parallel threads on the shaft: The object of this
arrangement is to form quick screw-threads on the shaft to give it a quick
longitudinal movement, at the same time having the threads close together so as to
reduce the shaft without leaving uncut spaces between the threads.
We may
employ any desired number of chasers and cutters in each set. We preferably
employ two sets of chasers and one set of cutters, as the second set of chasers may
be arranged to cut off the apices or ridges of the threads formed by the first set of
chasers, as above described.
The subject-matter claimed is hereinafter specified.
The accompanying drawings represent so much, only, of apparatus adapted for
carrying out this invention in the best way now known to us, as is necessary to
illustrate the subject-matter claimed. Unless otherwise indicated, the parts are of
usual well-known construction.
Arrows indicate the direction of movement of some of the moving parts.
Fig. 1 represents a plan or top view of the apparatus, with the polishing
mechanism in horizontal section ;
Fig. 2, a corresponding view of the cutter-head and its actuating gearing;
Fig. 3, an end view, and Fig. 4, a side view thereof;
Figs. 5 to 8, both inclusive, show detail views of the cutter-head, and tools on
an enlarged scale, Fig. 5 being a side view; Fig. 6, a longitudinal section there-
through, on the line 6-6 of the preceding figure; Fig. 7, a corresponding section,
on the line 7-7 of Fig. 5, and Fig. 8, a longitudinal, sectional diagram, illustrating
the method of cutting and

page_text: Fig. 9 represents a vertical, longitudinal section through the polishing
apparatus.
The mechanism is shown as mounted on a main frame A, A'. A band-wheel B,
driven from any suitable prime-mover, actuates a driving-shaft b, carrying a gear-
wheel B', engaging a similar wheel C, on a tubular shaft c, mounted in suitable
bearings on the main frame, and carrying a cutter-head D, secured thereto by a
screw or other suitable detachable connection.
The drawings show this cutter-head as provided with a set of four radial
chasers E, and an adjacent set of four radial chasers E', and also with a set of
cutters E, all of which are arranged equidistantly around the head, and separately
adjustable radially relatively to each other therein, sliding endwise in blocks d,
carried by the head D. The chasers and cutters are controlled by suitable set-
screws d. The blocks d are provided with suitable recesses to hold the cutters in
position and permit of their adjustment, the outer ends of the recesses being closed
by plates D', secured by bolts d', to the blocks d, which are provided with holes d³,
to receive the bolts.
We find the use of four or more sets of cutters and chasers most efficient, as the
strain thereon and constant wear thereof is rendered much less than would be the
case with a smaller number. By making those of each set separately adjustable,
we are enabled to readily remove or replace worn or broken parts, without removing
or regrinding the entire tool. We are also enabled to separately vary the
adjustment of the tools in each set or group relatively to each other and to the
shaft.
It will be observed by reference to Fig. 8, that the outer edges of the teeth
in both adjacent chasers E E', in each set or group are in the same horizontal
plane and each chaser cuts to the same depth, the chaser E', cutting grooves in
the threads formed by the chaser E, thus dividing the threads formed by the
chaser E into two threads of one-fourth the size, one-half of the body of the thread
being removed. By this arrangement, the tools are given an equal amount of
work to do, and the cutter E has a uniform resistance to overcome.
The wear of
all the tools is thus made more uniform.
The shafting F, to be finished, is held by suitable clamps g, in a bed-plate G,
sliding on suitable ways A', on the main frame. This clamp holds the rear end of
the shafting; the front end, after passing through the cutters, passes through a
suitable holding device hereinafter described.
A removable bushing f, intermediate of the shafting, and the tubular support c,
of the cutter-head, holds the shafting in accurate alignment. The bushing is
provided with a flaring mouth, to facilitate the insertion and centering of the shaft,
and differences between the shafting and cutter-head may be compensated by
varying the thickness of the bushing, thus accommodating shafting of different
diameters.
The end of the shafting is first fed into the opening in, the cutter-head by hand.
The first set of chasers E, cuts threads thereon, and thereafter automatically feeds
the shaft longitudinally, without revolving it, by means of such threads. This
first set of chasers is intended mainly to remove the outer scale from the shaft
and form the screw-threads thereon. We prefer to cut two or more threads
simultaneously on the shaft, as the feed is thus rendered more rapid, with less
corresponding increase of power and of beating action than would result from
cutting a single thread at the same rate of feed. This is effected by arranging
the teeth or threads in the chasers E, at a suitable pitch to form parallel screw-
threads on the shaft. In this way the desired speed of longitudinal movement is
given to the shaft, while the surface is uniformly reduced without leaving uncut
spaces between the threads. As will be observed, by reference to Fig. 8, the
chasers are so arranged as to cut the threads in such manner that their edges shall
be blunt instead of sharp.
The second set of chasers E', is so organized as to diminish the diameter of the
shaft by cutting away the apices or ridges of the screw-threads formed by the

page_text: first set of chasers, but not to cut below the bottoms of the grooves first formed-
see Fig. 8. This mode of cutting diminishes the power required to do the cutting,.
and aids in securing rapid and effective work. The cutter E³, finally reduces the
shafting to the desired diameter by cutting away the screw-threads left by the
preceding chaser. The arrangement by which the second set of chasers is made
to operate upon the threads cut by the chasers E¹, is shown in Fig. 8. It will be
observed that the distance between the first tooth in the chaser E', and the last.
tooth in the chaser E, is approximately one-half the distance between the apices
of the teeth in the chaser E.
As before remarked, more than two sets of chasers and more than one set of
cutters, may be employed in heavy work if desired, and the independent adjustment.
of the cutters and chasers in the cutter-head facilitates their adjustment relatively
to each other and to the axis of rotation of the shafting.
As the shafting leaves the cutters, some of the oil used in lubricating it during
the cutting operation adheres to it, and enables it more readily to retain abrading
or polishing material, such as emery, fed upon it from a suitable hopper, H, provided
with a feed-valve h.
The polisher is shown as consisting of rubbers I, of wood or other suitable
material, mounted on levers 11, rocking on pivots i, on a pulley J, driven by
suitable means, and revolving on a sleeve M, secured in a bracket N, on the frame..
The finished rod or shafting passes through and is supported by this sleeve. The
rocking levers I', are connected by adjustable links k, to a slide ring K, on the
sleeve M, and actuated by a hand-lever L, to vary the pressure of the rubbers on
the shaft.
By this improved apparatus, shafting is turned to give it a uniform symmetrical
surface at a minimum expenditure of power, and is by the act of turning fed
forward and delivered to polishers which automatically give to it a finished
appearance.
- Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is-
1. The hereinbefore described method of finishing shafting, which consists in
forming screw-threads thereon, automatically feeding the shaft thereby, removing
the apices or ridges of the screw-threads thus formed, then cutting away the
remaining threads, and polishing the shaft, all at one continuous operation, as
hereinbefore set forth.
2. The herein before described method of turning shafting, which consists in first
forming two or more parallel or duplicate screw-threads on the shaft to reduce its
diameter and automatically feed it forward at the desired rate of speed, and then
cutting away the threads to reduce the shaft to the desired diameter, substantially
as hereinbefore set forth.
3. The combination, substantially as hereinbefore set forth, of a cutter-head, a
chaser therein adapted to form screw-threads on the shafting and to feed it thereby,
a second chaser with its teeth set to cut grooves in the apices or ridges of the screw
threads thus formed, and a separate cutter adapted to remove the screw threads to
reduce the shaft to the diameter desired, and means for adjusting the chasers
independently relatively to each other and to the shaft.
4. The combination, substantially as hereinbefore set forth, in a machine for
turning shafting, of a cutter-head, a chaser therein having teeth adapted to form
screw-threads on the shaft, and to thereby feed it through the cutter-head, a second
separate chaser with its teeth set to cut grooves in the apices or ridges of the
screw-threads thus formed, and a cutter-head adapted to remove the resulting
screw-threads.
5. The combination, substantially as bereinbefore set forth, of a tubular cutter-
head, a chaser therein with teeth set to form screw-threads on the shafting and to
feed it thereby, a second separate chaser with its teeth set to form in the apices or

page_text: ridges of the screw-threads first formed grooves of the same depth as those formed
by the teeth in, the first chaser, and thereby double the number of threads, and
a cutter for removing resulting screw-threads.
6. The combination, substantially as hereinbefore set forth, of a tubular cutter-
head, a set of separate chasers therein, with the threads arranged at a pitch or
inclination to form two or more parallel quick-screw-threads on the shaft, and feed
it thereby, a set of cutters to remove the screw-threads, and means for adjusting
the chasers and cutters separately or independently in the head, relatively to each
other and to the shaft.
7. The combination, substantially as hereinbefore set forth, of the main frame,
a tubular shaft mounted in suitable bearings on the main frame, a cutter-head
secured to said tubular shaft, a series of blocks mounted in the cutter-head, radially
adjustable chasers and cutters mounted in said blocks, a bushing (f) within the
tubular shafting, and an end wise-moving clamp for supporting one end of the shaft
to be reduced as it passes through the cutter-head.
8. The combination, substantially as hereinbefore set forth, of a main frame, a
cutter-head mounted therein, separate chasers and cutters carried thereby, means
for adjusting the chasers and cutters relatively to each other and to the shaft, a
transverse clamping-frame in which the shafting is secured, and polishing
mechanism, the organization being such that the shaft is fed through the cutter
and polisher by means of the screw-threads cut on the shaft by the chasers and
subsequently removed before polishing.
9. The combination, substantially as hereinbefore set forth, of the main frame,
the cutter-head, the clamping frame carrying the shafting to be finished, the
tubular sleeve on the opposite side of the cutter-head, and the polishing mechanism
mounted on the tubular sleeve, the organization being such that the shafting is
supported by the tubular sleeve, while being polished and fed therethrough by
means of the screw threads formed upon the shaft, but cut away before polishing.
10. The combination, substantially as herein before set forth, of a rotating cutter-
head, provided with chasers and cutters, a hopper containing abrading or polishing
material, and a polisher, the organization being such that the rod or shafting is
fed through the polisher by the screw-threads formed thereon in passing through
the cutter-head.
11. The combination, substantially as herein before set forth, of the tubular
guide-sleeve, the pulley revolving thereon, the rocking levers carried by the
pulley, the rubbers carried by the rocking levers, the slide-ring on the guide-sleeve,
and its link connection with the rocking levers, the organization being such that
the finished rod or shafting is supported by the guide-sleeve, while being polished.
Dated this 6th day of February 1894.
PHILIP MEDART:
WILLIAM MEDART.