Improvements in Apparatus or Machines for Tapping Metals.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
Improvements in Apparatus or Machines for Tapping Metals.
I, CARL JAHN, Mechanician, of Königsplatz 22, Düsseldorf, in the German-
Empire, do hereby declare the nature of this invention to be as follows:-
This invention relates to apparatus for cutting screw threads by means of screwing
taps and more particularly to automatic means for disengaging and then withdrawing
the tap after it has penetrated into the hole for a given distance.
The screwing tap is clamped to a drill spindle which can be turned to the righte
or to the left by means of a reversing gear, chiefly 'consisting of two small bevel
wheels co-axial with the drilli spindle, a larger intermediate bevel wheel which
gears into the said bevel wheels on opposite sides, a coupling fixed to the: drill
spindle between the two small bevel wheels, and a pair of hollow shafts surrounding
the drill spindle, each shaft being loose on the drill spindle and carrying one of
the small bevel wheels...
The intermediate bevel wheel turns on a stud fixed to a frame which forms at
each end a bearing for the hollow shafts surrounding the drill spindle. If the
spindle is in a vertical position and' the coupling connected with the upper bevel
wheel, the spindle will turn in one direction: (say to the right), but when the
coupling is connected with the lower bevel wheel, the spindle will turn in the
opposite direction (to the left). The coupling has at its upper face a straight.
tooth or projection, adapted to lay itself against a similar tooth projecting downward
from the upper: bevel wheel, and from the lower face of the coupling extends
downward a straight tooth adapted to lay itself against a similar tooth projecting.
upward from the lower bevel wheel.
When the drill spindle is raised up, or withdrawn, so as to project only a
short distance below the frame of the apparatus, the coupling is in gear with:
the upper bevel wheel, and the drill spindle turns to the right; when the hollow
shaft of the upper bevel wheel is turned in the same direction. The tap now
penetrates into the hole, and the drill spindle: descends' until the upper tooth of
the coupling is: no longer in contact with the tooth of the upper tooth wheel. The
drill 'spindle now stops, and the frame together with the bevel wheels is raised
along the drill spindle by hand, until the tooth of the lower bevel wheel engages::
with the lower tooth of the coupling.
'
The drill spindle now turns to the left and screws the tap out of the hole,
until the lower tooth of the coupling has been raised above the tooth of the lower
bevel wheel. According to the depth of the holes to be tapped, the teeth of the
coupling sleeve and of the bevel wheel are made longer or shorter, or the teeth
are made exchangeable to suit various depths of tapping.
Instead of bevel wheels turning in opposite directions, other suitable reversing
mechanism may be used, and the apparatus may be connected with a drilling
machine or a lathe for producing the desired rotary motions.
Dated this 31st day of January 1895.
FAIRFAX & WETTER,
Agents for the Applicant.

page_text: apparatus for Tapping tais.
I, CARL JAHN, Mechanician, of Königsplatz 22, Düsseldorf, in the German
Empire, 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 apparatus for cutting or tapping screw threads by
means of screwing taps and more particularly to automatic means for disengaging
and then withdrawing the tap after it has penetrated into the hole for a given
distance.
In the further description of the invention reference is made to the accompanying
drawings, in which Figs. 1 and 2 are elevations, and Fig. 3 is a sectional elevation
of my invention.
T
The screwing tap is secured to a spindle s, like a drill spindle, which can be
turned to the right or to the left by means of reversing gear chiefly consisting of
two small bevel wheels, and 2, co-axial with the spindles, a larger intermediate
bevel wheel which gears into the said bevel wheels on opposite sides, a clutch
coupling having projections and fixed to the drill spindle between the two
small bevel wheels, and a pair of hollow shafts surrounding the spindle, each
shaft being loose on the spindle and carrying one of the small bevel wheels, as
shown in Fig. 3.
The intermediate bevel wheel r turns on a stud fixed to a frame which forms at
each end a bearing for the hollow shafts surrounding the spindle, as also shown in
the section Fig. 3. If the spindle is in a vertical position and the coupling connected
with the upper bevel wheel r', as shown in Fig. 1, the spindle will turn in one
direction (say to the right); but when the coupling is connected with the lower
bevel wheel, as shown in Figs. 2 and 3, the spindle will turn in the opposite
direction (to the left)...The coupling has at its upper face a straight tooth or
projection b, adapted to engage with a similar tooth a projecting downward from
the upper bevel wheel r; and from the lower face of the coupling extends down-
ward a straight tooth b', adapted to lay itself against a similar tooth a', projecting
upward from the lower bevel wheel r².
When the spindles is raised up, or withdrawn, so as to project only a short
distance below the frame of the apparatus, as shown in Fig. 1, the coupling is in:
gear with the upper bevel wheel, and the drill spindle turns to the right, when
the hollow shaft of the upper bevel wheel is turned in the, same direction. The.
tap now penetrates into the hole, and the drill spindle descends until the upper
tooth b of the coupling is no longer in contact with the tooth a of the upper bevel r.
The drill spindle now stops, and the frame, together with the bevel wheels,: is
raised along the drill spindle by hand, until the tooth a' of the lower bevel wheel:
engages with the lower tooth of the coupling, as shown in Fig. 2.
The drill spindle now turns to the left and screws the tap out of the hole until,
the lower tooth of the coupling has been raised above the tooth of the lower bevel:
wheel. According to the depth of the holes to be tapped, the teeth b and b' of
the coupling sleeve, and a, a', of the bevel wheels 1 and 2, are made longer or.
shorter, or the teeth are made exchangeable to suit various depths of tapping.
Instead of bevel wheels turning in opposite directions, other suitable reversing 4
mechanism may be used. The sleeve o is turned by hand or the apparatus may
be connected with a drilling machine or a lathe for producing the desired rotary
driving motion of the sleeve o. A pin p, fitted through the hollow shaft to which r¹
is secured, projects into and slides in the slot o' as the frame is raised or lowered,
and this pin transmits the rotary motion of o to s and r¹.
5

page_text: 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.
An apparatus for tapping holes in metals, comprising a rotatable spindles to
which the tap is secured, a coupling secured to the said spindle and having pro-.
jecting teeth 6 and 6, two bevel wheels and 3, having respectively projecting
teeth a, a, adapted to engage with the aforesaid teeth 6 and 6¹ and reversely rotate
the said spindle and tap, a bevel wheel engaging with the said bevel wheels
and, and a frame with bearings for hollow shafts surrounding the said spindle,.
substantially as and for the purpose described and shown in the drawings.
Dated this 19th day of October 1895.
FAIRFAX & WETTER,
433 Strand, London, Agents for the Applicant.