Improvements in Drilling, Boring, and Tapping Machines.
Year: 1893

page_text: Date of Application, 29th Sept., 1893
Complete Specification Left, 27th June, 1894-Accepted, 28th July, 1894
PROVISIONAL SPECIFICATION.
Improvements in Drilling, Boring, and Tapping Machines.
WILLIAM BENTLEY, 122 Westfield Road, Leeds, Engineering Draughtsman,
do hereby declare the nature of this invention to be as follows
-
The object of the present invention is to facilitate the quick withdrawal of the
drill- or cutter-spindles in drilling and boring machines fitted with feed-screws, as
well as to facilitate the adjustment of the said spindles in the direction of their
axes.
The combination I employ also allows the drilling machine to be instantly
converted into a tapping machine without the employment of change-wheels to suit
the varying pitches of the taps.
To effect these objects I construct that part of the machine which carries the
feed-screw of the spindle with a clasp-nut, the halves of which nut clasp or release
the circumference of the screw, when they are advanced or withdrawn in guides
formed in the head of the main frame by a cam which oscillates by chain & wheel,
or other hand-gear if worked by the attendant; or by an automatic trip action
when a required depth of hole has been drilled.
I also attach a balance-lever and weight to the machine, so that as soon as the
clasp nut is released from the screw, the balance-weight restores the spindle to its
highest or any other position, being controlled by a handle suspended from balance-
lever.
The wheel which effects the self-acting or hand-feed of spindle, when the clasp-
nut is in gear with the screw, is constructed with a key fitted to slide easily in a
key-way in the feed-screw,-(the latter being hollow as usual, and permitting the
rotation of the reduced shank of spindle within it), so as to rotate the feed-screw
through the clasp-nut, and so give longitudinal traverse to the spindle.
It is quite evident that with the above disengaging nut, (which with its cam
resembles those in use on many lathe saddles at the present time), the self-acting
feed motion of a drilling machine can be thrown out of gear, and then the spindle
will be free to follow a tap of any pitch.
The machine should be fitted with open and crossed belts, or quick reversing gear
to effect the quick withdrawal of the tap from the hole in the work.
I wish it to be understood that I claim to have invented the application to
drilling, boring & tapping machines of the above-named oscillating cam & clasp-
nut with balanced spindle in combination as above described, but I do not claim to
have invented the individual elements of the combination.
Dated this 26th day of September 1893.
COMPLETE SPECIFICATION.
Improvements in Drilling, Boring, and Tapping Machines.
I, WILLIAM BENTLEY, of 122 Westfield Road, Leeds, in the County of York,
England, Engineering Draughtsman 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 the present invention is to facilitate the quick withdrawal of the
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page_text: arill-spindles in drilling and boring machines fitted with screws for the feed motion,
and also to provide means for readily adjusting the said drill-spindles in the direction
of their axes; the combination by which these results are obtained also allows of
tapping being readily performed by the same machine without employing change-
wheels to suit the varying pitches of the taps employed and without occupying
more time than is required for removing the drilling or boring cutter from the
spindle-nose and substituting a tap.
To effect these objects I construct the machine in the manner shown on the
accompanying drawings Figs. 1 to 8, in which the same letters of reference are
employed in different views of the same parts.
Fig. 1 is a side elevation of the upper part of a vertical drilling machine with
hand disengagement of feed screw, to be more fully described hereinafter.
Figs. 2 & 3 are respectively the front and side elevations of the top part of a
vertical drilling machine with automatic release.
Fig. 4 is an enlarged sectional side elevation of the top part or feed screw boss
of a vertical drilling machine.
Fig. 5 is a sectional plan, and Fig. 6 is a front elevation of the same.
Fig. 7 is a front elevation (in section) of the shackle by which the balance-weight
lever and spindle of drilling machine are attached to each other.
Fig. 8 is a large scale sectional view of the thread of the feed screw and
nuts, which I prefer to make with tapering sides to facilitate engagement and
disengagement.
A is the main frame of the drilling machine, B the top boss which carries a
clasp nut made in halves N₁, N, which embrace or encompass the feed-screw S,
which (as usual) is hollow so as to rotate freely on the prolongation of the drill-
spindle D. I form the top boss B with slotted guides for the reception of the
half-nuts N₁, N., and I also provide a cam C keyed on a shaft E which is carried
in the cover plate F, and oscillated by hand wheel G so as to cause the pins H₁, H₂
(which are common to the half-nuts N₁, N, and the cam C), to slide in the cam-
slots I, I, respectively, and thus to advance or withdraw the half-nuts N, N, to
or from the feed-screw S.
In cases where the top boss B is too high from the floor for the attendant to
reach the hand wheel GI prefer to use a sprocket wheel and hanging chain or any
other appliance which affords ready control of the cam motion.
For the purpose of raising the spindle and its attachments when the half-
nuts N1, N, are opened I employ a balance lever L with weight W and compensating
link V. The balance lever L is secured to the top of the drill-spindle D by a
shackle M and collar with taper pin P (Figs. 4 and 7).
J is a handle suspended from balance lever L and is used to adjust the height of
the spindle D when the half-nuts are opened.
Q is the wheel which effects the self-acting or hand feed of the spindle when the
half-nuts are closed so as to gear with the feed screw.
which is constructed with a key T sliding in a key-way U planed in the feed
Qis keyed on a socket R
screw S, thereby rotating the feed screw within the clasp-nut and so giving
longitudinal traverse to the drill spindle.
When the half-nuts are opened the drill spindle is free to follow a tap of any
pitch just as in any screwing machine with advance worked by rack and pinion.
The machine may be fitted with reversing pullies to effect the quick withdrawal of
the tap from the hole it has tapped.
The above arrangement is applicable to radial drilling machines.
The same oscillating cam arrangement for releasing the spindle can also be
applied to horizontal drilling machines if a balance-weight with chain and pulley be
substituted for lever and link attachment.
When it is desired to drill holes of a given depth I employ the oscillating cam
and half-nuts in combination with a tripping motion shown in Figs. 2 and 3, in
which S is the feed screw on which is threaded the adjustable nut X which is set
to touch the lever Y when the required depth of hole has been drilled.: to the axis

page_text: of Y is keyed a bell-crank lever Z which is held by a spring against a projection
formed in the sector or quadrant q, which is keyed on the shaft of the disengaging
cam in place of the hand or sprocket wheel. The sector is provided with an arm
and balance weight, b, sufficiently heavy, when Z is tripped, to overcome the
friction of the cam and guides, and to open the clasp nut.
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:
1. The application of the oscillating cam and half-nuts to the balanced spindle
of drilling boring and tapping machines, as described and shown in Figs. 1, 4, 5, 6,
7 & 8.
2. The self-acting arrangement for stopping the feed of any drill spindle fitted
with the above oscillating cam, clasp-nut and balance levers, when a required depth
of hole has been drilled, as described and as shown in Figs. 2 and 3.
Dated this 26th day of June 1894
WILLIAM BENTLEY,
Applicant.