Improvements in Commutator Truing Devices.
Year: 1897

page_text: Date of Application, 14th Apr., 1897-Accepted, 19th June, 1897
COMPLETE SPECIFICATION.
Improvements in Commutator Truing Devices.
I, PERCY BOSTWICK BOSWORTH, Mechanical Engineer, of the City of Fort
Wayne, in the County of Allen and the State of Indiana, one of the United
States of America, 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 :-
My invention relates to improvements in means for truing or turning down
commutators employed upon dynamos, motors, generators and the like, and is
especially designed to be employed for such purpose without removing the
commutator from its supporting shaft.
My invention comprises a pair of adjustable blocks or castings adapted to be
rotatably mounted upon, and in diametric relation to the armature shaft; a two-
part adjustable collar adapted to be removably fixed upon said shaft adjacent to
the outer end of said blocks, and carry an upright feed-piu; a hand operating
crank rigidly fixed in one of said blocks for rotating the same about the armature
shaft; a removable driving-head adjustably mounted on said crank, carrying a
reciprocating tool-holder and means for imparting to the same an automatic
horizontal feed.
The object of my invention is to provide convenient efficient and economical
means for truing or turning down commutators by hand-power without removal
from the shaft in electrical power stations and other situations where commutators
are employed, thereby obviating the customary inconvenience, expense, and loss of
time incidental to such removal and transportation for repairs. The device is
80 constructed that if the commutator be rotated while it is secured in fixed
relation thereto, as may be desired in some situations, the cutting tool will maintain
a perfect alignment with the bearing proper; the device is also adapted for any
desired vertical adjustment, and for a reciprocating horizontal feeding-movement.
The novel feature of my invention consists in the construction and arrangement
for readily mounting a detachable hand-turning commutator truing or smoothing
device upon the armature shaft, and in the means for imparting to the tool-holder
a reciprocating horizontal feed.'
In the accompanying drawings similar reference numerals indicate corresponding
parts throughout the several views:
Fig. 1 is a side elevation of my improved device in position on the armature
shaft, showing the relative arrangement of the operating parts.
Fig. 2 is an end view of the same.
Fig. 3 is a sectional plan of the driving head taken on the line - of Fig. 1.
Fig. 4 is a vertical section of the driving-head showing the screw-threaded
adjusting collars thereon.
Fig. 5 is a detail of the adjustable blocks on which the hand-crank and driving-
head are mounted, shown in position on the armature shaft.
I employ more or less shaped blocks 3 and which are removable and
rotatably mounted upon the armature shaft 2 in immediate proximity to the
commutator 1; they are adapted to fit variously sized shafts, and are rigidly
connected together by proper holding screws 21 or in any other convenient manner.
The upper block 4 is provided with an upright boss 4' adapted to receive and
support the hand-crank 8. When the said blocks are clamped upon a large shaft

page_text: the block 3 is arranged as shown in Figs. 1 and 2. To fit a shaft of small diameter
the block 3 is provided at its apex and upon the outer surface thereof with a
recess 31 adapted to receive the lower face of the shaft 2, and the corresponding
sides of said blocks 3 and 4 are in parallel arrangement as shown in Fig. 5.
The said blocks thus arranged are of sufficient length to insure perfect alignment
and rigidity, and are secured against longitudinal displacement by the two-part
collar formed of the parts 5 and 6, similar in construction, and having a hexagonal
shaft opening. The said parts are adjustably connected and rigidly clamped upon
the shaft 2 adjacent to the outer end of the said blocks by means of the holding
screws 22. 7 is the feed pin hereinafter referred to with an angled end and fixed
in a boss upon the part 6.
In the block 4 is rigidly fixed by a screw-threaded connection the hand-crank 8.
arranged in parallel relation to said feed-pin and at right angles to the commutator
shaft it is provided upon its free end with any proper operating handle 9 removably
secured thereon. On this crank 8 is the sliding driving head 17 having a vertical
aperture to freely receive the said crank and a lateral perforation to freely contain
the tool-holder 12 in parallel relation with the shaft 2 on which the commutator is
fixed.
The driving-head 17 is provided at the top with a loose internally screw-
tbreaded collar 18 encircling the crank 8 and it is loosely secured in the said head
by the engagement of the annular flange 23 with a corresponding recess in said
head as shown best in Fig. 4. The driving-head 17 is rigidly held in any desired
position of vertical adjustment upon the crank 8, by means of the set screw 19 in
the collar 20 whose reduced externally screw-threaded portion is adapted to form
a connection with the collar 18. By this construction a limited vertical adjustment
of the said head can readily be made by rotating the collar 18.
The lower portion of the front face of the head 17 has a longitudinal
extension or flange 24 provided upon its upper surface with a semicircular
recess adapted to loosely receive the annular flange 16 on the internally screw
threaded sleeve 11 whereby the said sleeve is rotatably mounted and secured in
said head.
The bore or central opening of the sleeve 11 is preferably coincident with and
of the same diameter as that of the lateral aperture in the driving-head. In these
coincident circular openings the cylindrical tool-holder 12 is loosely mounted, all
tendency towards a rotary movement therein being obviated by a spline, feather
or key therein engaging a corresponding slit or slot on the head 17, but not
shown in the drawings.
The working end of the said tool-holder has an inclined slot or opening in
which the cutting-tool 14, of any proper form or size, is fitted and then secured
by the set-screw 15 which is set SO as to properly engage the face of the
commutator 1.
In a screw threaded opening in the rear end of the tool-holder 12 is secured
the reduced end of the screw 13 whose outer screw-threaded portion engages
the internal screw-threads of the sleeve 11, whereby, when the containing
sleeve 11 is rotated in its bearings it will impart to the said tool-holder an automatic
reciprocating horizontal feed.
At a proper point on said rotatable sleeve 11 is rigidly fixed by a set-screw or
otherwise, a feed-wheel 10 having fixed radial arms 25 adapted to successively
engage the free end of the feed-pin 7 above referred to.
The operation of the device is as follows: When the said device is properly
mounted on the armature shaft in operative relation with the perimeter of the
commutator 1, the operator first places the driving-head upon the crank 8 in its
approximate working position and then rigidly fixes it thereon by means of the set
screw 19 in the collar 20; the said head may then be further vertically adjusted
by rotation of the screw-threaded collar 18, as described. The cutting tool 14 may
also be readily adjusted in its containing slot to touch the lowest surface or point on
the perimeter of the commutator. By loosening the set screw 19 the operator can

page_text: readily and quickly run the tool around the perimeter of the commutator by hand.
to find the lowest point on its surface and then set the driving-head accordingly.
The operator next by the operating handle 9 of the crank 8 rotates the entire
device upon the supporting shaft.
As the tool-holder 12 is locked against rotation in the driving-head 17 and has a
screw threaded connection with the rotatable sleeve 11 by means of the screw 13,.
it is obvious that the engagement of the fixed feed-pin 7 with the radial arms of the
fixed feed-wheel 10 will correspondingly rotate the said sleeve 11 and thereby
produce an automatic reciprocating horizontal feeding movement of said cutting,
tool holder either in or out as desired.
The device can thus be readily adjusted and conveniently operated in all ordinary
situations, the armature in many instances not having to be removed from the
dynamo frame, the housing, pedestals and so forth being movable to the extent of
allowing the device to be applied to the said shaft.
The armature may also be put in between lathe centres aud the turning still be
accomplished from the bearing surface, thus making it possible to accurately turn
the same even when the said centres are injured so that the shaft does not turn
truly. The armature can also be secured to a bench by straps or other means and
the tool operated by hand-power exclusively, with the same accurate results.
My invention may be adapted and used for many other purposes than the one
specified; for example, it can be used for turning or cutting off shafting either on
the.bench or in position?in the hangers.
The speed of the horizontal feed of the cutting tool can of course be regulated
by varying the number of radial arms on the feed-wheel.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:
:
1. A commutator truing or turning device, consisting of a two-part base adapted
to be rotatably mounted on the armature shaft; means for securing the same
against longitudinal displacement; a hand-crank fixed in said base at right angles
to the axis of the said shaft and provided upon its free end with an operating
handle; a driving-head vertically adjustable on said crank, laterally apertured for
the tool-holder, and provided with an internally screw-threaded revoluble sleeve
arranged on the same axial line with said lateral aperture; a cylindrical tool holder
mounted in said sleeve and said aperture, as shown, arranged in parallel relation
with the said shaft, carrying a cutting-tool at its working end and having in its
rear end a rigid screw adapted for a horizontal feeding engagement with said sleeve,
as described; a feed-wheel fixed on said sleeve and adapted for an actuating
engagement with a feed pin arranged in a fixed position relatively to said shaft, all
substantially as described.
2. In a hand turning device for truing or turning down commutators, the
combination of a hand-crank rotatably mounted upon the armature shaft by means
of a pair of adjustable and separable supporting blocks; a two-part separable collar
fixed on said shaft for the purpose specified; an actuating feed-pin fixed to said
collar as shown; a laterally apertured driving-head mounted to slide on said crank,
having a pair of screw-threaded collars to afford a limited vertical adjustment as
described, and having a forwardly projecting rotatably mounted and internally
screw threaded sleeve whose longitudinal opening is coincident with said lateral
aperture in the driving-head; a reciprocating tool-holder mounted in said driving-
head and threaded sleeve as described, carrying in its working end a cutting tool,
and provided at its rear end with a rigid screw adapted for a horizontal feeding
engagement with said sleeve; a rigid feed-wheel mounted on said sleeve and
adapted for an actuating engagement with said feeding pin, substantially as
described.
3. In a commutator truing or turning device, a driving head provided with a
revoluble feeding sleeve for the reciprocating tool-holder; a tool-holder loosely

page_text: mounted in said head and engaged in said sleeve by a screw-threaded connection,
and adapted for a longitudinal feed therein; a cutting tool adjustably mounted in
the working end of said tool-holder; a feed-wheel fixed on said sleeve to rotate the
same; means for rotatably mounting said driving-head on the armature shaft with
the reciprocating tool-holder in parallel relation therewith; and means for actuating
the said feed-wheel, all substantially as described.
4. The combination in a commutator truing device of a driving-head having a
removable feeding-sleeve for the reciprocating tool-holder; a tool-holder loosely
mounted in said head and arranged in said sleeve by a screw threaded connection
and adapted for a longitudinal feed therein; a screw 13 mounted as shown in the
rear end of said tool holder and having a horizontal feeding engagement with the
said sleeve a cutting-tool adjustably mounted in the working end of said tool-
holder; a feed-wheel fixed as shown on said sleeve to rotate the same; means for
rotatably mounting said driving-head on the armature shaft with the reciprocating
tool-holder in parallel relation therewith; and means for actuating the said feed-
wheel, all substantially as described.
Dated this 14th day of April 1897.
Associate Agent for the Applicant,
J. C. CHAPMAN,
70 Chancery Lane, London, W.C., Chastered Patent Agent.