IMPROVEMENTS IN MACHINES FOR DRILLING AND BORING
Year: 1887

page_text: I NEWNHAM BROWNE, Fellow of the Institute of Patent Agents of 73 Cheapside
in the City of London do hereby declare the nature of the suid Invention for
"IMPROVEMENTS IN MACHINES FOR DRILLING AND BORING," and the manner of
performing the same to be particularly described and ascertained in and by the following
statement:-
The object of the present invention is a machine for drilling and boring improved
in the following particulars
1) The velocity of the drill and the pressure acting upon the same can be readily
and with certainty be regulated in accordance with the size of the hole to be drilled.
2) The pressure exerted upon the drill can be produced either by a lever and a
weight of a given size or by means of a screw in which latter case the lever and
weight serve to hold the drill to the work.
3) The driving cord remains of equal length for all the different velocities at which
the machine can be driven and its tension is also uniform.
The varying velocities for the drill are obtained by step or cone pulleys and guide
rollers. The driving pulley a mounted upon a crank shaft or other driving shaft has
the same number of grooves for the cord as the pulley cupon the drill-spindle & five
grooves being shown in the annexed drawings. When the cord runs as shewn in the
drawing, in the groove of smallest diameter of the pulley a and in that of largest
diameter of the pulley c will be driven at the lowest speed of the machine correspond-
ing with the largest drill to be used with the machine, say in the case illustrated in
the drawing, a drill of (five twelfths) of an inch. For the smallest drill for this
particular machine, one of (one twelfth) of an inch diameter, the proper speed is
obtained by running the cord in the groove of the largest diameter on a and that of
smallest diameter on pulley c. Intermediary positions of the cord gave intermediary
velocities. The length of cord will not only be the same for all the various speeds but

page_text: it will securely remain in any such position by reason of the following arrangement
applied to the machine,-
The two guide rollers d d have the same number of grooves as the cone pulleys a
and in tho present case therefore five. The spindles k. k. of the guide rollers d d
are carried by the upper part e of the upright and are adjustable thereon or therewith
in two ways. The upper part of the support in being moved over the slide g provided
therefor on the framing or bracket f, varies the position of the guide rollers d d not
only as regards height but also as regards their distance from the drill-spindle b. By
the adjustment the angle of inclination of the guide rollers d d is also varied (sco
figs. 2 and 4) as will appear from the following.
The screw is placed at an angle to the slide g. With the nut of this scrow is
connected the guide-piece i with the sides whereof the cylindrical ends of the spindle k
of the guide roller engage the latter turning moreover upon the pins t t. If the part e
of the support is placed in its highest position, as shown in the drawings, the guide
piece also assumes its highest position. By reason of the rotation to which the
spindles of the guide rollers are subjected, the guide rollers are also brought into their
extreme position, that which most approximates the vertical and in this position the
outermost groove thereon exactly corresponds to the smallest velocity both in height
and velocity as shown in the drawings. For this velocity, viz., for the diameter
of the holes to be drilled or bored at that speed, the position which the lower
edge of the part e is to take upon the slide g, is marked upon the latter, see fig. 4.
At the lowest position of the part e, the guidepiece i also reaches its lowest position
and by the action of the guide piece i upon the spindles & the guide rollers d d are
also made to assume their other extreme position that which is furthest from the
vertical. Then the innermost grooves of the guiderollers correspond to that position
of the cord which is required for the highest speed that is to say the speed suited for
the use of the smallest drill as indicated on the slide see fig. 4.
In the intermediary positions of the part e of the support marked upon the slide
according to the diameter of the drills to be employed, one of the intermediary
grooves on the guide rollers d d will correspond to one of the intermediary positions
of the cord.
Now as only one of the grooves upon the guide rollers d d corresponds with a given
position of the cord, the diameter of drill to be used therewith being indicated upon
the scale on the slide, a deviation from the required speed will be all the less possible
as the cord will hold only in that particular position but will slip off in any other
thereby indicating to the operator any mistake he may have made.
To enable the pressure upon the drill to be exerted either by a weighted lever or by
a screw, the following arrangement has been adapted to the machine.
A two-armed lever I is so mounted upon a pin´m in the framework that it may not
only turn upon the said pin but may be moved thereon in the direction its
length. To this end a block n loosely fitted upon the pin m is capable of sliding to
and fro in a slot of the lever 1, see fig. 6.-The lever embraces the coupling piece o
placed vertically over the drill spindle and this coupling piece o connects the drill
spindle b with the lever 1, as will appear from figs. 5 and 6.
The coupling piece o is free to turn on studs upon the lever, and the lever being
also capable of longitudinal motion on the block n will thus be enabled always to exert
pressure vertically upon the drill spindle-To cause pressure to be automatically
exerted upon the drill a weight p is placed upon the long arm of the lever as shewn in
the drawings. To enable the pressure to be readily and with certainty adapted to the
size of drill to be used a scale is marked upon the long arm of the lever, the
graduations whereof shew the position required for the weight p upon the lever for
drills varying in their diameters say by twelfths of an inch.
Besides the pressure exerted by said weighted lever, pressure may be put upon the
drill by the screw 7 also, which acts upon the coupling piece o and through this upon
the drill spindle b. In that case the weight p is placed upon the short arm of the
lever so that the lever I will serve as a counterpoise to raise the drill spindle when the
screw q is turned back.

page_text: A second screw provided over the short arm of the lever I serves in drilling small
holes to check the automatic motion of the lever by allowing a slight movement of
the latter as the said screw is gradually turned back and this prevents the drill
entering too suddenly when soft or porous portions of the material are reached drills
being frequently broken by the too sudden forward movement in such cases or when
the drill comes through the work.
By the side of the screw a bolt s is mounted in the bracket; this bolt slides
vertically and may be set by means of a screw. It serves as a striking piece for the
lever and, being suitably adjusted, limits its stroke when holes of a given depth are
to be drilled.
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 correspondent I declare that what I claim is :
1. In a machine for drilling or boring; the inclined slide g mounted upon the
framing and marked with a scale; the screw mounted in an inclined position; the
upper portion e of the support, the guide piece i, the spindles kk turning on pins or
studs t. t. and jointed to the guide piece i together, with the guide rollers d. d. having
a suitable number of grooves; the whole so combined and arranged as to allow the
driving cord to be exactly and readily adjusted for the velocity corresponding with the
drill to be used, without requiring the length of the cord to be altered.
2. In a machine for drilling or boring the lever turning on a pin m and capable
of sliding on a block n, the said lovor being marked with a scale; the coupling
piece o and the weight p capable of adjustment upon the lever, in combination with
the screw the whole so arranged as to allow pressure to be exerted upon the drill
either automatically by means of the weighted lever or by means of the screw.
3. In a machine for boring or drilling the screw » serving as a cheque upon the
lever-pressure and the bolts for limiting the motion of the lever.
Dated this 15th day of February 1887
NEWNHAM BROWNE.