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Патент USA US2410092

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Oct. 29,1946.
E. J. L`YNcH
vFiled July`12, 1944
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'By fowl/eb J.' LYNCH
¿A ATTO/wn
Patented Oct. 29, 946
' "
Edward J. Lynch, Detroit, Mich.
» Application July 12, 1944, Serial No. 544,592
5 Claims.
(c1. 'x7-_33)
members I4 and I5, the former ñxed by pins I6
on the shaft 3 in proximity to the coupling 4, and
the latter formed at its apex with a forwardly
extending sleeve I1 and being slidably mounted
This invention relates to rotary tools and par
ticularly to automatic feed heads for such tools.
It has been found desirable to derive the feed
of various small'tools, as drills and taps, fro-m the
centrifugaleresponse of Weights to a rotary drive
by such sleeve on the shaft 3. A pin I8 trans
versely fixed in .the tool holder 8 rigidly connects
in unison with the tools. . Such a feed is exem
the latter to the sleeve I'I, the shaft 3 having an
pliñed in the reissue patent to Broders, 21,341,
granted February 6, 1940.
Objects of the present invention are to simplify
and reduce the cost of prior centrifugal tool con
trol mechanisms, to provide a very simple and
effective brake mechanism for expediting deceler
ation when the drive is cut olf, and to provide an
improved control for an electric motor energizing
the feed head.
' These and various other objects are attained by
the construction hereinafter described and illustrated in the accompanying drawing, wherein:
Fig. 1 is an axial sectionalview of the improved
feed head showing its reciprocating parts re 20
Fig. 2 is a similar View showing said parts at
their forward limit of feed.
Fig. 3 isa cross section on 3-3 of Fig. l showing
the mo-unting of the centrifugal weights.
Fig. 4 is an enlarged axial sectional -detail of a
flexible Ycoupling used in the construction.
In these views, the reference character I desig
nates an electric motor having a tubular shaft 2.
elongated slot I9 in its tubular portion to permit
a predetermined travel of the pin relative to said
shaft. A permanent drive from said shaft to the
tool holder is moreover established by said pin.
A coiled spring 20 has an end portion slipped over
the sleeve I'I and abutting the bell-shaped mem
ber I5, the other end of the spring abutting a
brake shoe 2l of disk form fixed on the shaft 3
by a set screw 22 and adapted to frictionally
engage the inner face of the bearing 5. It is
important to understand that the spring 20 is not
intended nor adapted to apply the described
brake, the expansive effort of the spring being
resisted in both directions by the shaft 3. The
fixed relation of the shoe 2l to said shaft entails
a control of the _shoe taking effect through the
shaft 3 or at least tending to slidingly shift said
shaft. 'I‘he purpose of the spring 2G is to normally
yieldably establish the sliding member I5 at its
minimum limiting distance from the member I4
as per Fig. 1, this position being determined by
engagement of the weights I3 with the collar II.
Aligned with and normally spaced slightly from 30 Said spring permits the member I5 to Withdraw
from the member I4 responsive and in proportion
said shaft is an extension shaft 3 connected to
to outward actuation of the weights as will pres
and driven from the motor shaft by a coupling 4,
fiexible to compensate for any slight relative angu
ently more fully appear.
A unique feature of the invention is its utiliza
larity or inaccuracy of `alignment of the two
shafts. This coupling is hereinafter described in 35 tion of flexibility, of the coupling 4 to yieldingly
apply the brake. As best appears in Fig. 4, said
greater detail. The shaft 3 has its outer end
journaled in an outboard bearing 5 integrally
formed on a cylindrical casing 6 substantially
coupling comprises two collars 23, rfixed respec
8 .projecting beyond said shaft and the bearing 5
nulus 25 isvconstantly compressively stressed by
tively on the shafts 2 and 3 by set screws 24, and
an intermediate annulus 25 formed largely of
coaxial with the shaft 3 vand bolted as indicated
at ‘I to the motor. The shaft 3 has a tubular o-uter 40 rubber, into which are set pins 26 formed on said
portion wherein is slidably inserted a tool holder
collars. The arrangement is such that the an
to Vmounta rotary tool such as a drill or the illus
the two collars, the expansive reaction of the rub
trated tap 9. ’ To detachably mount the tool on
ber imposing a forward thrust on the shaft 3 such ~
its holder, there may be employed an ordinary 45 as to urge the brake shoe 2I against the bearing 5
collet andchuck I0 or some equivalent provision.
under `a predetermined pressure. Relief of this
Freely rotative and slidable on the .shaft 3,
pressure during the actual working or cutting
about midway between its tubular portion and
strokes of the tool will presently be explained.
inner end, is a collar I I rigidly carrying a plurality
A limit switch 21 of ordinary construction is
of outwardly radiating' rods I2. Freely slidable
supported by a bracket 28 on the rear end of the
>on said rods is a plurality of similar Weights I3,
motor at the extended axis of the motor, and a
equiangrularly spaced and elongated lengthwise of `
control rod 29 for the switch is slidingly extended
the shaft.- The ends of saidweights are beveled
_and curved _to engage and conform to the inner
faces of a` _pair of reversely disposed bell-'shaped
through the motor shaft 2 and partiallyA through
55 >the shaftV 3, the forward end of said rod being
threaded into the tool holder 8, and acting as a
set screw to secure the pin I8 firmly in place.
In use of the described feed head, the motor
circuit is normally broken at the switch 21 and
is closed in starting an operation by manual ac
tuation of a button 30 carried by the switch. The
the tool encounters the work, but also serves to
absorb the shock of tool impact, permitting a
more rapid advance of the tool to the work than
would otherwise be feasible.
What I claim is:
shafts 2 and 3 and tool holder and tool are now
nation with a driven shaft and a tool holder slid
driven, and the bell-shaped members I4 and I5
able along and rotative with said shaft to feed
1. In a feed head for rotary tools, the combi
are driven respectively by the pins I6 and I8
a tool forwardly to a piece o_f work, a weight and
from the shaft 3. Frictional engagement of the 10 means mounting it on the shaft for centrifugal
weights I3 by said mem-bers rotatively drives
outward actuation, a member slidable forwardly
them and they slide centrifugally outward on the
along the shaft responsive to outward actuation
rods I2. The weights thus exert a camming effect
on the two bell-shaped members, inducing a for
ward sliding of the member I5 and a compres
sion of the spring 20. The rotating tool holder
8 participates in this forward sliding due to the
of the weight, and a tool-feeding connection from
said member to the tool holder, of a brake shoe
fixed on the shaft, a non-rotative member for
wardly of and opposed to the brake shoe, a spring
compressed between the shoe and said slidable
pin I8, the length of the slot I9 predeterminedly
member, to yieldably resist forward movement of
limiting the advance of the tool holder and tool.
said member, and means yieldably exerting for
.During an initial portion of such advance, clear 20 ward pressure on the shaft to frictionally apply
ance of the tool from the work is taken up, the
the brake shoe to said Opposed member.
remaining advance representing the actual work
2. In a feed head for rotary tools, the combi
ing stroke of the tool. The tool, when it encoun
nation with a driven shaft and a tool holder
ters the work (not shown), is retracted slightly,
slidable along and rotative with said shaft to
together with the tool holder a small fraction of 25 feed a tool forwardly to a piece of work, a
an inch (less than a thirty-second suiiices) . Due
weight and means mounting it on the shaft
to the pin I8, the bell-shaped member I5 is're
for centrifugal outward actuation, a member
tracted with the tool holder, and the weights I3
slidable forwardly along the shaft responsive
being centrifugally held outward, transmit the re
to outward actuation of the weight, and a tool
traction to the member I4 and through the latter
feeding connection from said member to the tool
to the shaft 3. Compressibility of the rubber mem
holder, of a brake comprising a shoe fixed on
ber 25 of the coupling 4 permits the required Slight
said shaft, means reacting between the shoe and
retraction of the shaft 3, the extent of retraction
said sliding member to yieldably resist forward
being controlled by the normal slight clearance
movement of said member, and means yieldably
between the shafts 2 and 3. The brake shoe be 85 exerting forward pressure on the shaft to apply
ing fixed on the shaft 3, is thus retracted to clear
the brake.
the bearing 5 and is so maintained while the
3. In a feed head for rotary tools, the combi
tool is exercising its function. As the tool reaches
nation with a motor, a shaft driven by the motor,
the limit of its stroke, the rod 29 automatically
a tool holder driven by the shaft and slidable
opens the limit switch. The rubber member of 40 along the shaft for tool feed purposes, a casing
the coupling 4 is thereupon immediately relieved
carried by and laterally extending from the mo
of compressive stress applied by the work, and
tor and receiving said shaft, an outboard bear
the brake takes effect to greatly expedite decel
ing for the shaft carried by the casing, a weight
eration of the rotating parts and the return of
and means within the casing mounting the weight
reciprocable parts by the spring 20 to a normal
on the shaft for centrifugal outward actuation,
retracted position, as per Fig. 1.
a member slidable along the shaft in the direction
The function of the brake in the described
of tool feed responsive to outward actuation of
mechanism is of decided importance, since feed
the weight, and a tool-feeding connection from
heads of the improved character are required to
said member to the tool holder, of a brake shoe
constantly repeat their operation, and their eiii 50 fixed on the shaft within said casing for applying
ciency depends on the number of repeated oper
a braking pressure to the outboard bearing, a
ations that may be performed in a given time.
spring compressed between said slidable mem
Quick deceleration is hence a vital factor in re
ber and the shoe, yieldably resisting tool-feeding
ducing the interval between successive operations,
movement of said member, and means yieldably
whereas the momentum imparted by the rotating 55 exerting forward pressure on the shaft to apply
masses and more particularly the weights I3 tends
the shoe; the shaft being adapted for a limited
to unduly prolong rotation. >The fact that the
sliding travel relative to the motor and casing
brake is applied during the interval between
to give effect to the last mentioned means.
starting the motor and advancement of the tool
4. In a feed head for rotary tools, the combi
to its point of contact with the work has been 60 nation with a driving shaftv and a driven shaft, of
a flexible drive coupling interconnecting said
found no detriment, since said interval is much
too short to permit of objectionable wear or
shafts affording the driven shaft a limited travel
heating of the brake, and the fraction of power
toward the driving shaft and yieldably resisting
consumed in overcoming the brake during such
such travel, a tool holder driven by the driven
interval is of negligible importance.
shaft and slidable along such shaft for tool feed
Mounting- of the weights I3 to slide on the rods
purposes, a weight and means mounting such
weight on the driven shaft for centrifugal out
I2 in moving in and out is found to minimize
friction and also to overcome their tendency to
ward actuation, a member slidable along said shaft
in the direction of tool feed responsive to out
cock in prior constructions. It is a highly desir
able feature also that the weights freely float 70 ward actuation of the weight, a spring resisting
rotatively with relation to both bell-shaped mem
the specified sliding of said member, a tool feed
bers, thus avoiding a localizing of such wear as
ing connection from the slidable member to the
is imposed by the weights on said members.
tool holder, and a brake comprising a brake shoe
It is to be noted that the yieldable coupling 4 Y fixed on the driven shaft, said shoe being sub
not only provides for a release of the brake when 75 jected to- a thrust applied to the driven shaft by
the flexible coupling to normally apply the brake.
5. In a feed head for rotary tools, the combi
nation with a driven shaft, drive means for said
shaft, and a tool holder rotative with and slid
able along said shaft to feed a tool forwardly to
a piece of Work, a weight and means mounting
the weight on the shaft for centrifugal outward
actuation, a member rearward of and engaging
the weight and fixed onvthe shaft, a member >
shoe fixed on said shaft to engage the stationary
member, the shaft having a longitudinal play
relative to its drive means to afford the neces
sary travel of the brake shoe, means yieldably
exerting pressure on the shaft to urge the brake
shoe into restraining engagement with the sta
tionary mem-ber,> the tool holder, sliding mem
ber, weights, and fixed .member jointly forming
a means or transmitting to the shaft a retrac
forward of and engaging the weight and slidable 10 tion imposed on the tool by its engagement with
Work, whereby the brake is released upon such
on the shaft responsive to outward actuation of
the weight, a tool feeding connection from said
sliding member to the tool holder, of a brake
comprising a stationary member and a brake
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