Improvements in Machines for Tapping or Drilling.
Year: 1896

page_text: PROVISIONAL SPECIFICATION. .
Improvements in Machines for Tapping or Drilling.
We, ERNEST FRANCIS MOY, of Pratt Mews, Pratt Street, Camden Town,
Electrical Engineer, and THOMAS JOSEPH DIGBY, of 3, Museum Chambers,
Bloomsbury, Electrical Engineer, both in the County of London, do hereby declare
the nature of this invention to be as follows:-
This invention relates to machines for tapping or drilling holes in metals, or
other hard substances; the principal objects in view being to increase the output
of the work done, to provide an automatic action whereby the tap or drill is
withdrawn when the predetermined depth has been arrived at, and to partially or
wholly avoid the breakage of small taps or drills in doing the work. The improve-
ments herein described are especially applicable to machines used in drilling or
tapping small holes in brass and other metals. The machines are made of the
vertical or horizontal type, as required.
.
Referring to the vertical type, as the form best adapted for general work, a bed
plate has mounted upon it a frame adapted to carry a horizontal driving shaft,
working in suitable hearings. Upon the shaft is mounted a pully (preferably formed
as a speed cone) which may be conveniently driven from above, or in any other
ordinary manner. The pulley or speed cone works in an opening formed in the
frame between the bearings, in a well known manner; and to one end of the driving
shaft (which projects beyond cue of the bearings) is secured a toothless bevel wheel
having a wide frictional surface formed of leather or other suitable substance. At
the other end of the driving shaft is placed an end bearing, or other means, whereby
the end thrust on the shaft is sustained.
A vertical spindle is arranged to work in bearings formed in, or carried by, the
frame, and this spindle is required to rotate and slide in the said hearings, in the
well known manner of drilling machines. The lower end of the spindle is provided
with a small self-centering chuck, or other convenient means, to grasp and carry the
drill or tap used; while the upper end is furnished with a trunnion piece and lock
nuts whereby the end movement is imparted to the spindle by means of a balanced
lever. A longitudinal groove is cut in the upper portion of the spindle in which a
key or feather is adapted to slide, and a sleeve is made a working fit upon the
spindle and adapted to engage therewith in turning by means of a key or feather
working in the said groove, or by equivalent means.
The aforesaid sleeve is adapted to carry a pair of toothless bevel wheels, each
having a narrow frictional surface of leather or other suitable substance, the upper
one being of larger diameter than the lower one; both however, being adapted to
bear in turn on the above mentioned wide faced bevel wheel and to be driven by it.
On the sleeve, between the upper and lower bevel wheels, is also mounted a
crosshead, to which is connected a main linkwork, for the purpose of putting the
upper or the lower narrow bevel wheels into frictional contact with the wide faced
driving bevel wheel. The central eye of the cross head is formed with an upper
and lower ball race, and suitable cones, and balls, are provided to form a ball
bearing; with means of adjustment, and a lock nut on the sleeve, in the well known

page_text: manner of ball bearings. The upper and lower bevel wheels are secured to the
sleeve, while the sleeve engages with the spindle as before stated; consequently,
when the upper (or largest) bevel wheel is brought in contact with the driving
bevel wheel by depressing the ball bearing cross-head, the spindle is turned at a
certain speed in the ordinary entering or cutting direction for the tap or drill; but
when the crosshead is raised, the upper bevel wheel is released, and the lower (or
small) bevel wheel is brought in contact with the driving bevel wheel and turned
in the reverse direction of withdrawal, the spindle being driven at an increased
speed.
A collar is secured to the spindle, a little below the bottom bevel wheel, and a
stout spiral spring is interposed between the two. In depressing the crosshead
therefore, the spring is compressed, which tends to prevent breaking of the tap or
drill when the spindle is forced down upon,the work too hard or too rapidly, and
the attainment of this object is assisted by the balance lever before mentioned:
When the downward pressure of the. crosshead is removed, and the upper bevel
wheel released from contact with its driving wheel, the action of the spring and
counterweight of the balanced lever both tend to withdraw the tap or drill, and to
force the lower bevel wheel into frictional contact with the driving wheel; thus
reversing the. rotation of the spindle and unscrewing the tap (for example)' in
withdrawing it from the hole..
The main linkwork consists of the crosshead before mentioned, two connecting
arms pivoted. at their upper ends upon the trunnion arms of the crosshead, and at
their lower ends to a yoke piece arranged approximately in a horizontal position:
The yoke is of a U shape, the connecting arms being pivoted thereto near the
bottom or cross bar portion which thus acts as a distance piece between the sides of
the yoke, between which the spindle is situated. The ends of the yoke extend
toward the frame and are pivoted upon a stud which passes through the frame.
A spring is connected to one or both arms of the yoke at one end and at the other
it is coiled round the stud so as to force the main linkwork and the lower, bevel
wheel upward, to. act in the reverse direction and withdraw a tap or drill from a
hole. Near the end of one arm of the yoke. there is a small lug, to which is pivoted
a. pawl, and the pawl is also pivoted to the lower end of a small vertical rod. whose
upper end is screwed and passed.through the eye of a stud secured to the balanced
lever. An adjusting nut is placed on the screwed end of the rod above, and also
below the eyed stud; thus serving to limit the range of motion of the balanced lever,
as well as to trip the pawl when the spindle with its tap arrives at the desired
depth. A lever having a cam shaped end is mounted at that end upon the stud
which carries the yoke ends, and adapted to engage with the pawl aforesaid; while
its other end has a slot to receive a pin on the upper end of a rod extending upward
from.a. pedal.. The action of the main linkwork and its connections as described,
is to automatically trip the pawl when the spindle and tap have reached the required.
depth, and. to reverse the motion thereof by throwing the reversing bevel wheel into
gear with the driving bevel wheel.
A suitable stand or tablet is provided for supporting or holding, the work
operated on..
T
3½
FAIRFAX & WETTER;
.433 Strand, London; Agents for the Applicants.

page_text: Improvements in Machines for Tapping or Drilling.
We, ERNEST FRANCIS MOY, of 3, Greenland Place, Camden Town, Electrical
Engineer, and THOMAS JOSEPH DIGBY, of 3, Museum Chambers, Bloomsbury,
Electrical Engineer, both in the County of London, 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 machines for tapping or drilling holes in metals or
other hard substances; the principal objects in view being to increase the output
of the work done, to provide an automatic action whereby the tap or drill is
withdrawn when the predetermined depth has been arrived at, and to partially or
wholly avoid the breakage of small taps or drills in doing the work. The
improvements herein described are especially applicable to machines used in
drilling or tapping small holes in brass or other metals. The machines are made
of the vertical or horizontal type, as required.
In the further description of this invention reference is made to the accom-
panying drawings, which relate to a machine of the vertical type, as being the
form best adapted for general work. In these drawings, Fig. 1 is a front elevation,
as it presents itself to the operator, Fig. 2 being the side elevation.
In these drawings, a bed plate a has mounted upon it a frame b adapted to carry
a horizontal driving shaft c, working in suitable bearings d. Upon the shaft is
mounted a pulley e (preferably formed as a speed cone) which may be conveniently
driven from above, or in any other ordinary manner.
The pulley. or speed cone e
works in an opening formed in the frame between the bearings d, in a well known
manner; and to one end of the driving shaft e (which projects beyond one of the
bearings) is secured a toothless bevel wheel f having a wide frictional surface
formed of leather or other suitable substance. At the other end of the driving
shaft is placed an end bearing d', with screw adjustment, whereby the end thrust
on the shaft is sustained.
A vertical spindle y is arranged to work in bearings h formed in, or carried by,
the frame, and this spindle is required to rotate and slide in the said bearings in the
well known manner of drilling machines. The lower end of the spindle is provide.l
with a small self-centering chuck i, or other convenient means, to grasp and carry
the drill or tap used; while the upper end is furnished with a trunnion piece and
lock nuts whereby the end movement is imparted to the spindle by means of a
weighted lever k. A longitudinal groove is cut in the upper portion of the
spindle g in which a key or feather is adapted to slide, and a sleeve l is made a
working fit upon the spindle and adapted to engage therewith in turning by means
of a key or feather working in the said groove, or by equivalent means.
The aforesaid sleeve is adapted to carry a pair of toothless bevel wheels m, n,
each having a narrow frictional surface of leather or other suitable substance, the
upper one in being of larger diameter than the lower one; both, however, being
adapted to bear iu turn on the above inentioned wide faced bevel wheelf and to be
driven by it. On the sleeve l, between the upper and lower bevel wheels, is also
mounted a cross head o, to which is connected a main linkwork p for the purpose of
putting the upper or the lower narrow bevel wheels into frictional contact with the
wide faced driving bevel wheel.
The central eye of the cross head o is formed with an upper and lower ball race,
and suitable cones and balls are provided to form a ball bearing, with means of
adjustment, and a lock nut on the sleeve, in the well known manner of ball
bearings. The upper and lower bevel wheels m, n, are secured to the sleeve l,
while the sleeve engages with the spindle g as before stated; consequently, when
the large bevel wheel m is brought in contact with the driving bevel wheelf by

page_text: depressing the ball bearing cross-head o, the spindle g is turned at a certain speed
in the ordinary entering or cutting direction for the tap or drill; but when the
cross-head o is raised, the upper bevel wheel m is released, and the small bevel
wheel n is brought in contact with the wide surface driving bevel wheel ŕ and
turned in the reverse direction of withdrawal, the spindle being driven at an
increased speed by the lower hevel wheel n owing to its small diameter.
A collar g' is secured to the spindle g, a little below the bottom bevel wheel n,
and a stout spiral spring g' is interposed between the two. In depressing the
crosshead o therefore, the spring is compressed, which tends to prevent breaking of
the tap or drill when the spindle is forced down upon the work too hard or too
rapidly, and the attainment of this object is assisted by the weighted lever k before
mentioned. When the downward pressure of the cross-head o is removed, and the
upper bevel wheel m released from contact with its driving wheel, the action of
the spring counterweight of the balanced lever k tends to withdraw the tap or
drill, and to force the lower bevel wheel n into frictional contact with the driving
wheelf, thus reversing the rotation of the spindle g and unscrewing the tap (for
example) in withdrawing it from the hole.
stud
The parts of the main linkwork consist of the cross-head o, two connecting
arms p, p, pivoted at their upper ends upon the trunnion arms of the cross-head o,
and at their lower ends to a yoke piece pl arranged approximately in a horizontal
position. The yoke p is of a U shape, the connecting arms p being pivoted
thereto near the bottom or cross bar portion of p', which thus acts as a distance
piece between the sides of the yoke, between which the spindle g is situated. The
ends of the yoke p', however, extend toward the frame and are pivoted upon a
9 which passes through the frame. A spring (shown by dotted lines) is
connected to one or both arms of the yoke at one end, and at the other it is coiled
round the stud 9 so as to force the main linkwork and the lower bevel wheel
upward to act in the reverse direction and withdraw a tap or drill from a hole.
Near the end of one arm of the yoke there is a small lug s, to which is pivoted a
pawls, and the pawl is also pivoted to the lower end of a small vertical rod t
whose upper end is screwed and passed through the eye of a stud k¹, secured to the
balanced lever k. An adjusting nut t¹ is placed on the screwed end of the rod
above, and another one below the eyed stud, thus serving to limit the range of
motion of the balanced lever, as well as to trip the pawl s when the spindle with
its tap arrives at the desired depth. A lever u having a cam shaped end is
mounted at that end upon the study which carries the yoke ends, and adapted to
engage with the pawl s' aforesaid; while its other end has a slot to receive a pin
on the upper end of a rod ' extending upward from a pedal which is not shown.
The action of the main linkwork and its connections as described, is to auto-
matically trip the pawl s by contact with the adjusting nut t' when the spindle
and tap have reached the required depth, and to reverse the motion thereof by
throwing the reversing bevel wheel n into gear with the driving bevel wheel f.
The drawings show the lower wheel n engaged with fin the act of reversing the
spindle 9, and in this position the pawl s would ordinarily be disengaged from the
lever u.
But the upper adjusting nut t' is shown as slacked off the stud k' to show
the pawl when engaged with the lever u, the pawl and the lever being thus
locked together by the foot of the operator on the treadle (not shown) which,
pressing the rod u upward, locks the yoke p¹ and its linkwork o and p to the lever u,
through the intervention of the pawl s', and so brings the bevel wheel m down in
contact with f ready for entering the tap as aforesaid.
A suitable stand or table vis provided for supporting or holding the work
operated on.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to bé performed we declare that what we
claim is:-
1. The herein described improved machine for tanning or drilling having in

page_text: combination a frame, carrying a rotatable driving shaft in suitable bearings, on-
which is mounted at one end a wide frictional surface bevel wheel, means to resist
end thrust at the other end of the shaft, and a driving pulley between; a tap or
drill carrying spindle, a pair of narrow surface frictional bevel wheels of diverse
diameters mounted on the said spindle, a collar g', spring 9, sleeve l, and cross-
head o also mounted on said spindle, connecting arms, yoke piece, balanced lever,.
and means for arresting the working action of the spindle at the predetermined
depth, reversing its motion, and withdrawing the same; substantially as and for
the purpose herein set forth and shown by the drawings.
2. A tapping or drilling machine arranged and adapted as and for the purpose.
herein described and shown by the drawings.
Dated this 10th day of December 1896.
FAIRFAX & WETTER,
433 Strand, London, Agents for the Applicants.