Improvements in Apparatus for Grinding the Point Ends of Drills or for like Grinding Operations.
Year: 1892

page_text: Date of Application, 11th Apr., 1892 ·
Complete Specification Left, 16th June, 1892-Accepted, 16th July, 1892
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Grinding the Point Ends of Drills
or for like Grinding Operations.
We, ALFRED PALMER of the firm of Huntley & Palmers of Reading in the
County of Berks, Biscuit Manufacturers, and FRANCIS ERNEST BLACKMORE of
55 Queen's Road Reading in the County of Berks, Engineer in the employ of the
said firm do hereby declare the nature of our invention to be as follows:-
The object of this invention is to provide apparatus for grinding the point ends
of drills or for like operations and is especially suited for efficiently grinding the
point ends of twist drills so that they are ground and "backed off" by one con-
tinuous operation without requiring adjustment for different size drills but capable
of ready adjustment to grind the point ends to any required angle and with any
required degree of "backing off" the grinding being effected so as to give an equal
amount of clearance and length of lip at both sides. The apparatus morcover
enables the drill to be ground so that it has a true central point at its end so that
the drill can be started to work in a very small centre hole and the drill during its
work continues to make its own centre on which it works so as to keep the drill true
and prevent its sides bearing upon the sides of the hole being bored which is a defect
in the use of drills as hitherto ground without a true central point.
An apparatus constructed according to this invention consists of a frame or bed
plate on which the bearings for the emery wheel or like grinding device are
mounted. The drill to be ground is held in a holder capable of revolving in a
bearing on an arm centered to the bed plate at the end nearest to the emery wheel
and adjustable to the angle to which the point end is to be ground. This angle
may
be determined by a gauge bar which is arranged to be brought into its gauging
position so that its gauging edge is truly parallel with the transverse line of the
periphery of the emery wheel. The holder carrying the drill is rotated by means
of gearing which causes the arm carrying the bearing of the said holder to be
vibrated upon its centre to alter the angle at which the point end of the drill is
presented to the emery wheel so as to give on each side of the point end the
deviation from a cone corresponding to the amount of "backing off." This may be
effected by making the part which carries the first motion shaft or axis of the
operating gear fixed and connecting the moveable arm carrying the drill holder
to it by a spring which draws the said arm towards the said fixed parts.
first motion shaft or axis carries a pinion which engages with a toothed cam
wheel which is so shaped that excentric portions thereof come into gear with
the pinion corresponding to the amount of "backing off" to be given to the
point end at each side of the drill during each revolution thereof so that the
arm carrying the drill holder (and consequently the drill holder and drill carried
by it) is moved upon its centre at such times during the revolution as correspond
with the degree of "backing off" to be given to each side of the point end of
the drill.
The
As it is desirable to withdraw the drill from the emery wheel when the gaps of
the drill between each of the sides being ground come opposite the said wheel the
drill holder is moved endways (in the direction of its axis) at such time which
may be effected by a face cam on a collar on the holder bearing on a corresponding
face cam on the bearing of the said holder.
The gearing for giving the movements described may be arranged in any other
suitable way for instance both gearing pinion and wheel may be true circles the
pinion being mounted on an adjustable and fixable pin to adjust the degree of

page_text: throw given to the drill holder by altering the excentricity of the pinion the axis
of the toothed wheel on the holder being capable of moving in a slot and being
kept in gear with the pinion by a spring which connects the axes of the pinion and
toothed wheel. The apparatus may be used for grinding twist drill points or
drill points generally or for such other grinding operations as it is or may be
applicable to. i
1
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, Agents."
COMPLETE
SPECIFICATION.
Improvements in Apparatus for Grinding the Point Ends of Drills
or for like Grinding Operations.
We, ALFRED PALMER of the firm of Huntley & Palmers, of Reading, in the
County of Berks, Biscuit Manufacturer and FRANCIS ERNEST BLACKMORE of
55 Queens Road, Reading, in the County of Berks, Engineer, in the employ of the
said firm, do hereby declare the nature of the said 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 this invention is to provide apparatus for grinding the point ends
of drills or for like operations and is especially suited for efficiently grinding the
point ends of twist drills so that they are ground and "backed off" by one con-
tinuous operation without requiring adjustment for different size drilis but capable
of ready adjustment to grind the point ends to any required angle and with any
required degree of "backing off" the grinding being effected so as to give an
equal amount of clearance and length of lip at both sides. The apparatus more-
over enables the drill to be ground so that it has a true central point at its end so
that the drill can be started to work in a very small centre hole and the drill during
its work continues to make its own centre on which it works so as to keep the drill
true and prevent its sides bearing upon the sides of the hole being bored which
is a defect in the use of drills as hitherto ground without a true central point.
An apparatus constructed according to this invention consists of a frame or bed
plate which may be mounted in connection with an emery wheel or like grinding
device as usual. The drill to be ground is held in a holder capable of revolving
in a bearing on an arm centered to the bed plate at the end nearest to the emery
wheel and at a point such that the point of the drill being ground is in the axial
line of the centre on which the said arm turns. The said arm is adjustable to the
angle to which the point end of the drill is to be ground.
This angle may be determined by a gauge bar which is arranged to be brought
into its gauging position so that its gauging edge is truly parallel with the
transverse line of the periphery of the emery wheel and cuts at a right angle the
aforesaid axial line.
The holder carrying the drill is rotated and as it rotates the arm carrying
the bearing of the said holder is vibrated or oscillated upon its centre to alter the
angle at which the point end of the drill is presented to the emery wheel so as to
give on each side of the point end the deviation from a cone corresponding to the
amount of "backing off."
To give the proper cutting edge at the part of the point end of the drill which
is between the grooves in the drill the drill is withdrawn from the emery wheel or
grinding device when each groove comes opposite the said wheel or device.
In order that our invention and the manner in which it may be carried into
practical effect may be well understood we will describe with reference to the
accompanying drawings machines constructed in accordance with our invention..
Figure 1 is a plan and Figure 2 an elevation of one arrangement.
Figures 3 and 4 are corresponding views of a modified arrangement and

page_text: Figures 5 and 6 are respectively a sectional elevation and a plan of a further
modification in the arrangement,
Figure 7 shows a detail common to all the arrangements shewn which are in
principle the same and we have marked the parts which correspond in the several
arrangements with the same letters of reference in all the figures.
Referring to Figures 1 and 2 A is the bed plate and B is the first motion shaft
or stud carried in a bearing upon a standard C having a foot c which is provided
with a projection engaging in the groove a in the bed plate A and fixed in a
position (according to the angle of the point end to be ground) by the screw and
nut. The groove a is an arc struck from the centre a. is a handle secured
to a pinion B mounted loosely on the shaft or stud B but the pinion may be
provided with a pulley for operating it by power. D is the moveable arm centred
to the bed plate A at a² the point of the drill being operated upon being situated
in the same line as the axial line of the centre a². The said arm D has in it
a bearing D in which rotates the drill holder E in which the drill is secured
by a chuck e or in any other convenient way. A spring F connected at one end
to the pin 3 and at the other end to the pin d, respectively on the foot c and the
arm D, draws the said arm D towards the foot c. The pinion B' mounted on the
first motion shaft or stud B engages with a toothed cam wheel E' on the end of
the drill holder E which cam wheel is so shaped that as the eccentric or projecting
portions thereof come into gear with the pinion B2 the drill holder carrier D is
inoved away from the foot c and the angle at which the drill is presented to the
grinding wheel is altered twice in each revolution of the drill holder and consequently
the drill point is ground to the amount of backing off to be given to the said point
at each side of the drill during each revolution thereof the arm D carrying the
drill holder turning upon its centre a when the revolution of the cam wheel causes
the said arm to be moved away from the foot c. By using cams of different throws
the degree of "backing off" can be varied as desired. The point of the drill being
operated upon being as aforesaid situated in a line with the axial line of the
centre a has a true point imparted to it. In order to make the sharp edges at a
Figure 8 of the drill it is necessary to withdraw the drill from the emery wheel
when the gaps or channels of the drill between each of the sides being ground
coune opposite the said wheel. To effect this the drill holder is moved end ways
(in the direction of its axis) at such time which may be effected by a face cam 2
on a collar on the holder bearing on a corresponding face cam d² on the bearing D'
of the said holder. The spring g between the bearing D2 and the collar on the
holder presses the cam face e against the cam face d².
There are two cams on the faces e d* corresponding to the two gaps or channels
in the drill being ground as shewn in Figure 7.
The gearing of device for giving the movements described may be arranged in
other ways for instance the operating handle hand wheel or pulley by which
rotation is given to the tool holder may be fixed on the axis of the tool holder and
wheel E2 and then the wheels E' and B can be without teeth the rotation of the
cam wheel E2 against the roller B giving the vibratory or oscillatory movement to
the arm Das. aforesaid. Figures 3 and 4 shew an arrangement wherein both
gearing pinion 13 and wheel E are true circles the pinion being mounted on an
adjustable and fixable pin or being adjustable and fixable on a pin or stud B by
the nut and screw as shewn the said pin having a squared part engaging. in a slot 62
in the pinion B to adjust the degree of throw given to the drill holder by altering
the eccentricity of the pinion B, or the axis of the toothed wheel on the holder
may be capable of moving and of being adjusted in a slot. The pinion B³ and
wheel E are kept in gear by the spring arranged as hereinbefore described.
Figures 5 and 6 shew an arrangement wherein the driving pinion B2 and its shaft
or stud B are carried in a prolongation of the bearing D the vibration of the
arm D upon its centre a being obtained by means of a disc B³ having in it a
groove in which is adjustable the crank pin connected by the rod h to a
standard H the connection being made so to allow the rod to swivel in either

page_text: When
direction, and to meet any twisting movement there may be in the rod it can be
formed in two parts connected by screwing the one into the other as at h².
the pinion B2 is rotated it rotates the drill holder as in the other arrangements and
the disc B being constrained by the rod h secured to the fixed standard H causes the
arm D to vibrate on its centre a twice during each rotation of the drill holder the
pinion B2 being half the diameter of the wheel E. By adjusting the pin ³ in
the groove in the disc B³ the amount of backing off can be varied. To bring the
point of the drill into the correct position in its holder before being fixed so that
it is in the same line as the axial line of the centre a³ a gauging bar I is provided
which is shewn by the full lines out of its gauging position. Its gauging position
is shown in dotted lines its gauging edge in that position cutting at a right angle
the aforesaid axial line. Jindicates the position of the emery wheel when the
drill is being ground.
It will be evident that the machine may be made to grind drills having other
number than two ribs and grooves the gearing and cams being arranged to give a
number of vibrations to the arm D in accordance with the number of wings or ribs
and grooves in the drill to be ground and the cams de being in number and
position such as to withdraw the drill as each groove comes opposite the grinder.
The apparatus may be used for grinding twist drill points or drill points
generally or for such other grinding operations as it is or may be applicable to.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. In an apparatus for grinding the points of drills and the like, a drill carrier
capable of oscillating or vibrating on a centre the extreme point of the drill being
gauged so as to be situated in the same axial line as that of the centre on which
the said carrier oscillates or vibrates in combination with means for rotating the
drill and means whereby as the drill rotates the angle of the carrier is altered by
being turned upon the said centre to give the required "backing off" at each
wing or rib of the drill on each revolution thereof substantially as hereinbefore
described.
2. In an apparatus for grinding the points of drills or the like, a carrier for
the drill and means for rotating it and means whereby as the drill revolves the
angle of the carrier is altered to give the required backing off at each wing or
rib of the drill at each revolution thereof and means for removing the drill
from the grinder as each groove in the drill comes opposite to it, substantially as
and for the purpose herein before described.
3. The several arrangements and combinations of parts constituting machines
or apparatus for grinding the points of drills substantially as hereinbefore described
and illustrated respectively in Figures 1 and 2, in Figures 3 and 4 and in Figures 5
and 6 of the accompanying drawings.
Dated this 16th day of June 1892.
J. H. JOHNSON & CO.,
Agents.