Year: 1888

page_text: [Communicated from abroad by SANFORD DANIELS LELAND, Machinest, GEORGE
SHERMAN LEWIS, Book-keeper, and FRANK ED. FAY, Salesman, all of Holyoke,
Massachusetts, United States of America.]
I, HENRY HARRIS LAKE of the firm of Haseitine, Lake & Co., Patent Agents
Southampton Buildings, in the County of Middlesex, 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:—
The object of my invention is to provide a tap-head which will comprise within
itself means for holding and revolving a screw-tap and also for automatically stopping
the revolution of the tap as the end of the latter approaches the bottom of the hole or
orifice being tapped.
To this end my invention consists in a tap-head comprising within itself a friction
clutch by means of which a revolving movement is transmitted from a revolving
spindle to the tap, and automatic releasing devices for rendering said clutch inoperative
to turn the tap, as the end of the latter approaches the bottom of the hole within
which it is operating.
My invention also comprises certain details of construction hereinafter fully described
and particularly pointed out in the claims.
Referring to the drawings in which like letters designate like parts in the several
figures.
Figure 1 is a side elevation of the parts composing the tap-head as they appear
previous to being assembled.
Figure 2 is a similar view of the same parts after being assembled.
Figure 3 is a vertical section of the parts as shown in Figure 1.
Figure 4 shows the position of the releasing devices during the operation of
the tap.
Figure 5 shows the position of the same parts after being tripped.
Figure 6 is a plan view of the tap-receiving hub.

page_text: Figure 7 is a similar view of the clutch-holding and releasing wedges and their
toggle-joint connection.
Figure 8 is a plan view of the upper end of the tap, and an inverted plan of the
bushing by which it is held in its hub.
The letter A designates the spindle having the stem a by means of which the tap-
head is adapted to be secured to the spindle of the drill-press by which it is operated.
I have deemed it to be unnecessary to show the press as my invention relates wholly
to the tap-head, and because it will be understood by persons skilled in the art to
which the invention relates that, by inserting the stem of spindle A within the socket
in the spindle of the ordinary drill-press, the former can be revolved and also caused
to advance and recede at will.
At the end opposite to said stem a the spindle A terminates in the annular flange a¹,
from the face of which project two lugs a², preferably located at diametrically opposite
points on said flange, as shown.
At its lower end spindle A is provided with a central bore to receive the stem b of
hub B, and at the inner end of said bore with an interior chamber a³. An orifice a*
extend laterally through the shell of the spindle into said chamber, and an interior
lug a extends upwardly from the bottom of said chamber, both for a purpose
presently to be described.
The letter B designates the hub having at its upper end stem adapted to fit
loosely within the bore of spindle A and to project within chamber a³, said stem at
its upper end being provided with a transverse orifice to receive a pin 61, which pin,
being of greater length than the diameter of the bore in the spindle, serves to retain
the hub and spindle in operative engagement with each other, while permitting a
limited movement longitudinally, and a free rotary movement, of the stem within
the spindle. At its lower end hub B is bored centrally to receive the tap, and at the
inner end of the socket thus formed it is provided with an interior chamber 12 of
less diameter.
In order to adapt the hub to receive and hold taps of different sizes, I prefer to
provide the taps with a bushing e, the outer diameter of which is substantially
that of the bore of the hub, so as to fit closely therein, while the inner diameter of
of each bushing will correspond with that of the particular tap with which it is
designed to be used. I also prefer to make the upper end of the tap and an orifice
in the head of the bushing of corresponding angular conformation as, shown in
Figure 8, whereby the former is prevented from revolving within the latter. To
sécure the bushings e within the hub I provide the latter with an interior gib 63
and with an adjusting screw & bearing at its inner end against said gib, whereby
the latter can be tightened against the. bushing. A screw having its head located
in a countersunk depression in the hub is inserted at its inner end into said gib, near
the upper end of the latter, and a coil spring bearing at one end against the bottom
of the depression in the hub and at the other end against the head of said screw
flexibly retains the gib in its position.
In the plane of the lower end of the chamber the hub B is provided with an
opening extending transversely through it, and, immediately in front of or below
said opening, with an annular flange 67 having the same outer diameter as flange a¹ of
the spindle. Seated within radial grooves in the upper or rear face of said flange bare
two blocks 68 adapted to have a limited movement toward and away from each other.
To the inner end of each of said blocks is pivoted a link 6 the free ends of which links
project within a transversely slotted plug 610 where they are secured by a pivot b12
passing through said plug across the slot therein. Said links and plug thus form a
toggle-joint and, said plug being fitted loosely within chamber 6, it follows that by
moving the plug upwardly within said chamber the blocks 68 will be drawn inwardly
or toward each other, and by moving the plug downwardly said blocks will be moved
outwardly or away from each other. Upon their upper surface the blocks 68 are
inclined downwardly toward their outer ends at a slight angle to their bottom surface
as shown.
The letter D designates a bearing-ring the outer diameter of which
corresponds to that of flanges a¹, and 67, the inner surface of which is bevelled as

page_text: shown, and which is provi.led with recesses d in its lower surface to receive loosely the
ends of the blocks 8. The letter E designates a second bearing-ring whose outer
diameter is slightly less than the inner diameter of ring D, and the outer surface of
which is bevelled to correspond with the inner surface of said ring D, whereby it is
adapted to closely fit within the latter ring, as shown in Figures 2, 4 and 5. The
lower surface of said ring E is also preferably bevelled to correspond with the
inclined upper surfaces of blocks 68, as shown, and upon its upper surface said ring
is provided with two lugs e located at diametrically opposite points thereon. The
bearing-ring D is secured to flange b' of the hub by screws or bolts passed therethrough
and entering holes 613 in the flange, see Figure 6. The rings D, E thus form a friction
clutch by which, when the latter is closely held within the former, motion imparted to
ring E will be transmitted to ring D and hub B. Said ring E, however, is capable
of a slight vertical movement within ring D, and its position therein is governed
by the position of blocks 68 which act as wedges against its lower surface. It will be
obvious therefore that when said blocks occupy their outermost positions ring D and
hub B will move in unison with ring E, and when said blocks occupy their innermost
positions said ring E can revolve freely without turning ring D or hub B. When
the parts are assembled by inserting the stem of hub B within spindle A and inserting
pin 6 through orifice a in the spindle and through the orifice in the upper
end of stem, and the spindle is lowered upon the hub, the lugs a² on the former
are brought within the plane of revolution of lugs e on ring E and by their contact
therewith transmit the revolving movement of the spindle to said ring. When the
lugs a² and e are in engagement with each other pin &¹ lies above the plane of lug a
in chamber a³ of the spindle and is free to revolve within said chamber when by releasing
the friction clutch D, E, hub B becomes stationary while the spindle and ring E
continue their revolving movement. By raising the spindle, however, until the pin
is brought into contact with the bottom of chamber a³ and lugs a² are elevated above
the plane of lugs e, the lug a³ is brought within the plane of said pin and, by its con-
tact therewith, causes hub B to revolve with the spindle in withdrawing the tap from
its orifice after the completion of its work. The devices which govern the position of
plug 60 and blocks 68 are a coil spring 1 located in chamber above the plug and
normally retaining it in its lowest position, and a rod C₁ extending centrally through
the tap and projecting beyond the ends thereof, a flange at the upper end of said rod
retaining it within the tap. Said rod is free. to move lengthwise within the tap, and,
until the latter approaches the bottom of the orifice within which it is operating,
occupies the position shown in Figure 4. By the continued movement of the tap the
lower end of said rod is brought into contact with the bottom of the orifice and it is
gradually elevated within the tap until its upper end abuts against the bottom of
plug and by elevating the latter against the stress of spring 614 and moving
blocks 68 inwardly, it releases the clutch D, E, and thereby stops the movement of the
tap. I have shown the hub as being provided with a shoulder 1 immediately above
flange 7, said shoulder having its upper surface bevelled to correspond with the bevel
of the lower surface of ring E, whereby said shoulder is adapted to support said ring
when the blocks 8 are drawn inwardly, but it is obvious that other means for support-
ing said ring can be employed and I do not wish to limit myself to the use of such
shoulder.
The operation of the tap-head thus constructed will be obvious from the above
description. The stem a of spindle A being secured within the spindle of a drill-press
or within the head-stock of a lathe, and the tap C corresponding in size to the particular
orifice to be tapped, being inserted in hub B by means of its bushing c and applied to the
orifice the drill-press spindle or lathe head-stock is set in operation in the usual manner.
The movement of spindle A is transmitted through lugs a², e, and rings D, E to hub B
and the tap, the blocks 68 and rod C¹ being in the position shown in Figures 2 and 4.
When the tap reaches the bottom of the orifice the rod C¹ moves the blocks 68 to the
position shown in Figure 5, as previously described, and the tap ceases to revolve.
The movement of the drill-press spindle or lathe head-stock is then reversed in the
usual manner,
and the reverse movement of spindle A being transmitted to hub B

page_text: through pin 6 and lug a³, the tap is drawn from the orifice and the operation is
completed.
It will be observed that the tap-head herein described is wholly automatic so far as
stopping the movement of the tap is concerned, thereby avoiding all possibility of
injury to the tap through the carelessness of the operator. It will be observed, further-
more, that by varying the length of rod C, the movement of the tap can be stopped
at any desired distance above the bottom of the orifice in which it operates, when it is
not desired to tap said orifice entirely to the bottom thereof. The tap-head herein
described is also adapted to tap holes which extend entirely through the material in
which they are located, in the usual manner, and its automatic feature can be utilized
in such case by arranging a suitable stop upon the rear side of the stock and opposite
the orifice extending therethrough, with which the end of rod C" can contact as the
tap approaches the rear end of said orifice.
I do not wish to limit myself to the construction herein described in all of its
various details, as modifications therein can be made without departing from the
spirit of my invention.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to
me by my foreign correspondents I declare that what I claim is :-
1. The self-acting tap-head herein described consisting of a hub having a socket to
receive the tap, a spindle operatively connected with said hub by means of a clutch,
a tap seated in the socket of said hub, and a clutch-releasing device located within said
tap and projecting beyond the end thereof, substantiaily as and for the purpose set
forth.
2. The self-acting tap-head herein described, consisting of a hub having a socket to
receive the end of the tap and having connected therewith a friction-clutch and devices
substantially as described for causing the two members of said clutch to engage and be
disengaged from each other, and a spindle provided with contact devices for engaging
and revolving one of the members of said clutch, arranged and operating substantially
as set forth.
3. The tap-head herein described consisting of a hub having means for securing the
end of a tap therein and having connected therewith a friction-clutch and sliding
wedge-shaped blocks connected together by a toggle-joint for locking and releasing
the two members of said clutch, in combination with a spindle having projecting lugs
for engaging lugs upon one of the members of said clutch, and a tap having centrally
disposed therein a rod or similar device for operating said toggle-joint to release said
clutch, substantially as described.
4. The tap-head herein described consisting of spindle A having a central bore and
projecting lugs as shown, hub B having stem adapted to fit loosely in the bore of said
spindle and having at its opposite end a socket to receive the tap, said socket terminating
in the chamber 62, blocks located in a transverse opening in said hub and connected
by links with plug 610 located in said chamber 6, ring D secured to said hub and
having its inner surface bevelled as shown, ring E located within said ring D, said
ring E having its outer surface bevelled as shown and having projecting lugs e,
spring located in chamber 62 above said plug 610, and tap having rod Ci
extending longitudinally therethrough, combined and operating substantially as set
forth.
5. In a tap-head the combination with spindle A having a central bore terminating
in chamber a3 and having lug a projecting upwardly within said chamber and
orifice a leading into said chamber, of hub B provided with the tap receiving socket,
friction-clutch, and clutch releasing devices substantially as described, said hub
having stem adapted to be inserted within the bore of spindle A and to project
within said chamber a³, said stem being provided at its upper end with an orifice
extending transversely therethrough. and pin & adapted to be inserted through
orifice a of said spindle and seated within the orifice in said stem b, substantially
as and for the purpose described.

page_text: 6. In a tap-head the combination with hub B having a socket at its lower end,
of bushing c closely fitting within said socket, said bushing having in its
end
upper
an orifice of angular conformation, and tap C closely fitting within said bushing and
having its upper end shaped in cross-section to correspond with the orifice in said
bushing, substantially as and for the purpose set forth.
7. In a tap-head the combination with hub B having a tap-receiving socket in its
lower end, of gib 3 located within a recess in the wall of said socket, screw b³ secured
at its inner end to said gib and having its head located within a counter-sunk
depression in said hub, a spring located between the head of said screw and the
bottom. of said depression, and adjusting screw 4 bearing at its inner end against
said gib, substantially as and for the purpose described.
8. In a tap-head, the combination with spindle A having lugs a², of hub B having
flange b', bevelled shoulder 65, and transverse opening 6, wedge-shaped blocks
sliding within grooves in said flange and shoulder, said blocks being connected
together by a toggle-joint, ring E having its outer and lower surfaces bevelled as
shown and having lugs e projecting from its upper surface, and ring D having its
inner surface bevelled to correspond with the bevel of the outer surface of said ring E,
substantially as and for the purpose described.
Dated this 27th day of November 1888
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.