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Патент USA US2387582

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BROACHING APPARATUS
Filed Maich las;` v1945
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Patented Oct. 23, 1945
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UNITED
2,387,582
STATES
PATENT
OFFICE
BROACHING APPARATUS
>Fred W. Helmîng, Waterbury, Conn.„assignor to
The Bristol Company, Waterbury, Conn., a cor
poration of Connecticut
application March 18, 1943,.serial No. 479,545
44 Claims. (c1. 90-33)
This invention relates to broaching operations,
ing the broaching operation. Since this involves
and is more particularly concerned with a novel
apparatus adapted for use in connection with a
screw machine wherein a breaching action forms
one of a number of successive operations, of
no actuation of clutches or other starting and
stopping devices, the mechanism may be very
materially simplified, the wear and tear of opera
tion greatly reduced, and the breaching time re
which the majority require rotary motion of the
work with respect to the processing tool. In the
duced to a minimum.
In the drawing:
manufacture of set screws and the like on a pro-
I
~
I
Fig. 1 is a top elevation of a portion of an
automatic screw machine including a device em
duction basis, it is customary for the material
upon which operations are being performed to be
bodying the principles oi the invention.
carried in a rotating spindle and rto have pre- v
Fig. 2 is a side elevation partly in sectionV of a
sented theretothe tools necessary to the several
broach mounting embodying the principles of in
forming operations in the production of a fin
ished unit. It is obvious that if the successive
Feb. 3 is a front elevation of the same.
operations can be carried out without bringing to 154 Figs. 4 and 5 are a side and front elevation
vention.
I
,
rest the rotating spindle which carries the mate
respectively of a spindle adapted to the purposes
rial, there will be effected a saving in time and
of the invention.
also a decided reduction in wear and tear on the
In some methods of production of screws hav
ing a recessed or splined head, it is necessary ‘
In Fig. 1 is shown a top `view of a screw ma
chine or turret lathe adapted to the purposes of
the invention. Mounted upon a lathe bed I0, is`
a headstock II havingtherein a rotatable spin
that certain operations be performed by a broach
or similar tool whose motion relative to the
workpiece is purely axial or longitudinal. Since
it is frequently expedient that said axial com
ponent of the forming process be performed be
die I2 adapted to be rotated about its axis by
means of a pulley I3. Carried by the spindle I2
is a chuck I_4 adapted to grip a workpiece I5
which is to be subjected to certain formi?gproc
esses. Slidably mounted upon the lathebed I0,
machinery.
»tween two operations involving rotary motion,
it becomes necessary that the workpiece be tem
porarily brought to a state where it will have no
rotary motion with respect to the broach. In
the conventional method for performing such op
erations, it has been customary to make use of a
broach rigidly fixed to the tailstock or turret
head of the machine, and to present this tool
to the workpiece only after the latter has been
brought to rest by stopping the motion of the
spindle in the headstock. ,
It is an object of the present invention te pro
vide a means for `carrying out the breaching ac
and adapted for motion therealong in a sense
O
.
parallel to the axis of the spindle I2, is an. apron
I6 carrying a turret head Il, which may be r0
tated with respect to said apron about an axis
perpendicular `to that of the’ spindle I2.
Mounted upon the turret head I 'I is a plu
rality of tools or forming elements adapted to
perform in a predetermined succession a series
In the
, of operations upon the workpiece I5.
drawing are indicated three such tools, viz., a
drill I8, a broach I 9, and a threading die 20.
The turret head I1 may, of course, carry other
tools, but the three which have been mentioned
tion as one of a series of successive operations 4.o are suiiîcient to illustrate the purposes and prin
without the need for bringing the spindle to rest
or in any way altering its velocity.
ciple of the invention. The mechanism for ro
tating the turret head Il with respect to the
In the present invention it is proposed to pro
apron I6, and for advancing said apron together
vide a rotatable mounting for the breaching tool,
with the turret head carried thereby, in order
45
and further to provide means whereby said
to present to the workpiece I5 such forming ele
mounting will automatically be caused to rotate
ments as may be borne by the turret head, con
coaxially with, and at the same speed as, the
stitutes no part of the present invention, and,
spindle at the time of being presented to the
being well known to those familiar with this class
workpiece to carry out the breaching operation.
of machinery, herein requires no further de
Thus, instead of it being necessary to provide 50 scription
means for bringing the spindle to rest during the
As an example of a process in which each of
broaching operation, it is only required to leave
these tools forms a part, consideration may be
the breaching tool mounting free to rotate as
given to certain elements in the machining of a
much as may be necessary to maintain the broach
recessed head set screw from a length of bar stock.
55
at the same angular velocity as the spindle dur
The stock is represented by the workpiece I5,
Pr
.
_
2,387,582
which is ñrmly gripped in the rotating chuck
I4 for the purpose of having the several de
sired operations performed thereon. The fol
chuck and a bevelled surface 38, and lso disposed
that as the breaching element is juxtaposed
thereto the extremity of one or other of the
lowing operations represent normal practice in
springs `32, 33, will be engaged by the surface 31,
causing the collet 28 to assume the rotation of
the chuck I4 and the broach thus to be rotated
The turret head I1 being first so positioned that
at the same velocity as the workpiece I5. As .the
the drill I8 lies on the axis of the machine, the
broach is farther advanced it will engage the
apron I6 is advanced toward the headstock I1,
workpieceV I5 and will enter the previously drilled
presenting the drill I8 to the workpiece I5 and
causing a hole of the proper depth to be centrally 10 hole in the end thereof, and will carry out its
breaching operation in the same manner as
drilled in the projecting end thereof. The apron
though both the workpiece and the broach were
I6 is then withdrawn, and the turret head I1
devoid of angular rotation. As the broach is
rotated to such a position that the broach I9
forced >to the bottom of the recess, the springs
lies on the axis of the machine. In the art as
heretofore practiced, it would now be necessary 15 32, 33 will yield sufficiently to permit free axial
motion of the broaching tool; and as said tool is
to bring the chuck I4 to rest, after which the
withdrawn, said springs will assist in clearing the
apron I5 carrying the turret head I1 would be
broach from the workpiece.
advanced, and the broach I9 forced into the hole
, While the springs 32 and 33 provide means for
which had been drilled in the extremity of the
workpiece I5. This broach being shaped to a 20 bringing the rotating collet 28 up to the same
'speed as the chuck I4 before any stress is ap
suitable contour (as for example that Shown in
plied to the broach I9, it has been found in the
the set screw fully described and set forth in U. S.
smaller sizes of the device, where the inertia of
Letters Patent 1,075,710, issued to D. S. Goodwin,
the movable parts is relatively low, that these
October 14, 1913), the interior of the recess will
thus be given a nuted or splined conformation, 25 springs may be omitted, and that upon its first
adapted for engagement by a similarly conformed
engagement with the recess in the workpiece I5
the broach I9, together with the collet 28 and
wrench. The apron I6 Yis again retracted, and
associated parts, will assume the angular Velocity
the broach I9 withdrawn from the recess in the
of the chuck I4 without damage or objectionable
screw, after which iït is necessary that the spin
die I2 carrying the workpiece I5 again be 30 strain. Upon withdrawal of the broach I9 from
the workpiece I5, the turret head I1 will be ad
brought into rotation. The turret head I1 is
vanced to a new position, and the threading oper
rotated toA such a position that the die 20 is
ation carried out by the die 20 as hereinbefore
caused to lie on the axis of the machine, after
described.
„
which the turret head is again advanced and
the die presented to the projecting portion of the .35 The terms and expression whichl I have em
ployed are used as terms of' description, and not
rotating'workpiece I5 to form thereon a suitable
of limitation, and I have no intention, in the
screw thread.
use of such »terms and expressions, of excluding
As hereinbefore noted, my invention enables
any equivalents of the features shown and de
the broaching action to be accomplished with
out bringing the spindle I2 to rest or in any way 40 scribed or portions thereof, but recognize that
various modifications are possible within the
altering its velocity. This may be effected by
scope of the invention claimed.
means ysuch as illustrated in Figs. 2-5 of the
the forming of a set screw having a recessed head:
drawing.
I claim:
.
-
1. Broaching apparatus comprising holding
More particularly, -in Fig. 2 is shown a side
elevation, partly in section, of a mounting which 45 means for a workpiece, means for rotating said
holding means, a breaching tool holding means
permits free rotation of the broach I9. A base
adapted to be rotated about the axis of said
portion 22, having a projecting cylindrical shank
workpiece and simultaneously advanced along
23 adapted to be ñxed within the turret head I1
said axis with respect to said workpiece, and
of the screw machine, is provided with a recess
2li and a clamping plate 25 adapted to be secured 50 means cooperating with the first mentioned hold
ing means for transmitting to said broaching tool
'to :the base portion 22 by means of suitable bolts
rotary movement about only the axis of said
23, and to form therewith a housing for a ball
workpiece, said transmitting means comprising a
A bearing men1ber21 of a type especially adapted to
helically conformed spring extending from one
resist thrust or axial.stresses. Carried within
the ball-bearing 21, and free to rotate with the 55 of said holding means and Aadapted to engage one
of its ends with a portion of the other of said
inner portion thereof is a collet 28 secured to said
holding means prior to engagement of said
bearing by means of a nut 29 freely rotatable
broach with said workpiece and thereby to act as
with said collet in the recess 24. Centrally fitted
a driving member for said broach in a circum- ,
within the collet 23 and secured therein by a
set screw or other suitable clamping means, not ’ 60 ferential sense while remaining resilient in an
axial sense.
shown in the drawing, is a bushing 38 adapted to
2. Broaching apparatus comprising holding
support the broach I9 by engagement with a
means for a workpiece, means for rotating said
suitably threaded screw 3| abutting upon the
holding means, a broaching tool holding means
rearward end of said broach.
»
Secured to the front end of the collet 28 is a 65 adapted to be rotated about the axis of said work
piece and simultaneously advanced along said
pair of- helically formed semi-circular springs
axis with respect to said workpiece, and means
32 and 33, normally projecting a slight distance
cooperating
with the ñrst mentioned holding
axially from the surface 0f said collet, but adapt
means for transmitting to said broaching tool ro
ed to be compressed into substantial engage
ment therewith under the action of a longitudi 70 tary movement about only the axis of said work
piece, said transmitting means comprising a leaf nal force.
spring extending from one of said holding means
Secured to the chuck I4 is a ring 35, shown in
and adapted to engage a portion of the other of
Figs. 4 and 5, and having in the surface thereof
said
holding means prior to» engagement of said
a notch 38 formed by the intersection of a plane
surface 31 parallel to the axis of rotation of the 75 broach with said workpiece and thereby to relieve
3
2,387,582
said broach of undesirable torsional stresses in
init'iating said rotation thereof.
3. Broaching apparatus comprising holding
means for a workpiece, means for rotating said
holding means, a breaching tool holding means
adapted to be> rotated about the axis of said Work
piece and simultaneously advanced along said
axis with respect to said work piece, and means
cooperating with the ñrst mentioned holding
while remaining axially resilient and relieving
said tool of undesirable stresses in initiating said y
rotation thereof.
_ 4. Broaching apparatus comprising holding
means for a workpiece, means for rotating said
holding means, a broaching tool holding means
movable axially of said workpiece and also free
for rotation with said workpiece for forming rec
tilinear surfaces on said workpiece, and means
means for transmitting to said broaching tool ro 10 interposed between the last mentioned holding
tary motion about only the axis of said work
means and the means for rotating said workpiece
piece, said transmitting means comprising a
for transmitting rotary movement from said ro
spring extending from one of said holding means
tating means to said breaching tool, said trans
towards the other and of such length as to en
mitting means comprising a spring of such length
gage a portion of the other of said holding means 15 as to transmit rotation to said broaching tool
prior to engagement of said broaching tool with
said workpiece for driving said broaching tool
while remaining axially resilient.
FRED W. HELMING.
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