Improvements in Grinding Machines.
Year: 1898

page_text: Improvements in Grinding Machines.
I, CHARLES HOTCHKISS NORTON, of 158, Melrose Street, in the City and County
of Providence and State of Rhode Island, United States of America, Mechanical
Engineer, do hereby declare the nature of this invention to be as follows:-
In grinding machines where straight and tapered work is to be ground to
minute accuracy, it is desirable that the table upon which the head and foot-
stocks are guided and held be so constructed that the centres will always lie
in the same straight line at whatever point on said table they may be located.
In practice I have found that with the usual horizontal surface for guiding the
head and foot-stocks the area of the guiding surface or straight edge for main-
taining the centres in the same straight line at whatever point along the table
they are situated, is necessarily small, with the result that said guiding surface
soon becomes worn causing errors in the alignment of the centres and conse-
quent inaccuracies in the work. The wear and errors are increased in cases
where the stocks are drawn against the guiding edge, and in these cases errors may
also be caused by drawing the stocks against the straight edge with varying
force, owing to the yielding of oil, moisture, or dirt between the straight edge
and the stock. Moreover water, ground particles of steel, emery, or dust are
liable to get between the horizontal guiding surface and the stocks and raise
or tip said stocks from their true position making it impossible to fasten them
at different points along the table with sufficient accuracy.
One object of the present invention is to overcome these objections and to
provide a guide for the head and foot-stocks which shall have a large area for
maintaining the centres in the same straight line whatever their position upon
the guide. A further object is to provide a means for clamping the head-stock
and foot-stock which will allow the clamping pressure to vary without materially
affecting the accurate alignment of the centres.
A further objection to the grinding machines as heretofore constructed is
that the guide for the head and foot-stocks is so constructed and arranged that
water and dirt from the grinding will get upon said surfaces unless said guide
is protected by so-called water guards which are formed in sections, and must
be inserted between the head and foot-stocks after they have been adjusted to the
proper position. These water guards are usually telescoped or lapped one upon
the other to a certain extent, but in all cases they must be removed and replaced
in position in changing the adjustment of the centres for different lengths of
work. Moreover these guards are not perfectly water-tight, and a small amount
of water and dirt works through upon the guiding surfaces and is liable to
destroy the accuracy of the centres when they are adjusted for a different length
of work.

page_text: A further object of the invention is accordingly to provide a table so constructed
that the guiding surfaces are fully protected from water and dirt without the
use of guards which must be removed and replaced for different lengths of work.
A further object of the invention is to provide means for obtaining accurate
adjustment of the slide upon which the grinding wheel is mounted. In machines
for accurate grinding, this slide must be moved in ordinary use as little as one
eighth of one thousandth of an inch, and many times as little as one twentieth
of one thousandth of an inch, and these small adjustments, as well as the larger
adjustments, must be made accurately and be maintained as any error in adjust-
ment of the slide produces double such error in the work. The slide must also
be heavy to prevent vibration of the revolving wheel, and to move this heavy
weight the small amounts necessary for accuracy of work requires that all con-
ditions of friction and oil be the best, and that there be no torsion in the connec-
tions between the indexing wheel and the slide on which the grinding wheel
is mounted. Even in cases where by reason of favorable conditions and great
care the required accurate adjustment of the wheel slide is obtained, the jarring
of the floor or machine will often cause the slide to advance from one twentieth
to one quarter of a thousandth of an inch causing the wheel to cut the work too
small. In fact, it is very seldom that an operator will succeed in moving the
wheel slide accurately to these delicate measurements, but must usually move
it less than desired to insure against cutting the work too small, and then by
very skillful jarring of the index wheel obtain as near as possible the desired
adjustment. Again, when it is desired to move the wheel a definite amount
by the aid of the index wheel with its graduations, it is nearly impossible to
find the exact point where all backlash is taken up and the slide really begins to
move.
I have found by experiment that even when all connections between the
grinding wheel slide and index wheel are the best yet the oil on the revolving
and thrust bearings of these connections will yield and store up energy enough
to cause a horizontal slide to move uncertain amounts, even though the sliding
contact be very loose and the slide is floating freely on the best oil. In such
a case, also, jars usually cause those slight movements of the slide towards the
work which result in the errors above referred to.
I have attempted to overcome these objections by connecting to the wheel
slide a weight suspended over a pulley, but find that this weight must be much
heavier than the slide, thus adding so much to the inertia to be overcome in
moving the slide that the errors are increased rather than diminished. I have
also tried a spring instead of a weight, but find that the different tension at
different points is objectionable and that accuracy of adjustment cannot be
insured in this manner.
As far as I know previous to my invention all grinding machines were sub-
ject to the errors and objections referred to which it is one of the objects of
my invention to overcome. This I have accomplished by placing the grinding
wheel slide upon an incline sufficient to cause it to slide down the incline by
gravity even when the conditions of friction and oil are not the best. With
this construction a part of the weight of the slide is transferred from the sliding
surface to the bearings of the moving connections where it is more easily carried
and the friction upon the sliding surface is reduced. Moreover with this con-
struction the slide rests firmly upon its moving mechanism and it is possible
to allow the sliding contact between the slide and its support to be very loose
and to float the slide freely upon oil, and a jar can cause no movement of the
slide towards the work. The torsion of the connections moreover remains prac-
tically wound up or constant so that any perceptible movement of the index
wheel either way is followed by a corresponding movement of the slide. I find
with this construction I am enabled to grind duplicate work within narrow
limits of accuracy without any skill or caution except to place the index wheel
at the proper graduation thus making it possible for accurate work to be done

page_text: by relatively unskilled labor, and also making it possible to use automatic
graduating or feeding devices for the slide.
The invention may be applied to machines in which the work is fed across
the face of the grinding wheel, or to machines in which the grinding wheel
travels along the work, and the work centres may be mounted upon a swivel
table to adapt the machine for taper work, or the machine may be adapted for
taper work by adjusting the ways on which the grinding wheel support is moved
longitudinally.
In carrying out the invention, the head and foot-stocks may be mounted upon
a support having an upwardly extending front side and a substantially vertical
rear side upon which is formed a longitudinal way for supporting and guiding
the head and foot-stocks. The way is provided with a broad substantially vertical
bearing face which maintains the alignment of the centres in the direction in
which an error will produce the greatest inaccuracy in the work. The longitu-
dinal way may have upper and lower bevelled edges, the upper one of which
is engaged by shoulders on the stocks, and the lower one by clamps carried by
the stocks. The head and foot-stocks extend forward over the upper edge of the
support to bring the work centres out of. line with the longitudinal way so that
the water and grit dripping from the work will not fall upon the way, but will
run down the front side of the support. The forward ends of the head and
foot-stocks may also extend below the upper edge of the support, and the front
side of the support may be extended over and beyond the rear side so that the
upper edge overhangs the rear side and effectively shields the longitudinal way
from any water or dirt thrown off by the work or grinding wheel.
The support for the head and foot-stocks may be a swivel table provided with
a base extending from the rear to the front side, and resting upon the upper
surface of a bed. Such a table will be seen substantially triangular in cross
section, and will resist strains that would deflect an ordinary table from a straight
line.
The grinding wheel is mounted in a slide which is supported upon an inclined
way, the inclination of which is such that the slide will move down the way by
gravity. The slide may be moved upon the way by any suitable mechanism.
In order that the machine may be adapted for taper work, it is necessary that the
axis of the grinding wheel and the axis of the work should remain in the same
plane whether they are parallel or at an angle to each other, and whatever the
position of the grinding wheel slide on its way. Means should therefore be
provided for maintaining the work supporting centres, and the axis of the grind-
ing wheel in the same plane. This may be done, in case a swivel table is used
for supporting the centres, by providing the bed upon which the table rests
with an inclined upper surface parallel to the way on which the grinding wheel
slide is supported. In case the grinding wheel support is mounted on longi-
tudinal ways, this axis of the grinding wheel and the work centres may be main-
tained in the same plane by mounting the ways so that they will swing in
planes parallel to the way on which the grinding wheel slide is supported.
An overhanging arm may be mounted in a bracket secured to the frame back
of the work centres, and the front end of said arm may extend down in front of
the work and carry a bearing block for preventing vibration of the work.
The head or foot-stock may be provided with a tool socket in which socket a
truing tool may be held as by a set screw, and the grinding wheel sharpened or
trued without removing the work from the centres.
229
1
•
1000
CHARLES HOTCHKISS NORTON.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.

page_text: Improvements in Grinding Machines.
I, CHARLES HOTCHKISS NORTON, of 158, Melrose Street, in the City and County
of Providence, State of Rhode Island, United States of America, Mechanical
Engineer, 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:
In grinding machines where straight and tapered work is to be ground to
minute accuracy, it is desirable that the table upon which the head and foot-
stocks are guided and held be so constructed that the centres will always lie
in the same straight line at whatever point on said table they may be located.
In practice I have found that with the usual horizontal surface for guiding the
head and foot-stocks the area of the guiding surface or straight edge for main-
taining the centres in the same straight line at whatever point along the table
they are situated, is necessarily small, with the result that said guiding surface
soon becomes worn causing errors in the alignment of the centres and conse-
quent inaccuracies in the work. The wear and errors are increased in cases
where the stocks are drawn against the guiding edge, and in these cases errors may
also be caused by drawing the stocks against the straight edge with varying
force, owing to the yielding of oil, moisture, or dirt between the straight edge
and the stock. Moreover water, ground particles of steel, emery, or dust are
liable to get between the horizontal guiding surface and the stocks and raise
or tip said stocks from their true position making it impossible to fasten them
at different points along the table with sufficient accuracy.
One object of the present invention is to overcome these objections and to
provide a guide for the head and foot-stocks which shall have a large area for
maintaining the centres in alignment horizontally; that is, in the direction in
which an error would produce the greatest inaccuracy in the work. A further
object is to provide a means for clamping the head stock and foot stock which
will allow the clamping pressure to vary without materially affecting the accurate
alignment of the centres.
A further objection to the grinding machines as heretofore constructed is
that the guide for the head and foot stocks is so constructed and arranged that
water and dirt from the grinding will get upon said surfaces unless said guide
is protected by so-called water guards which are formed in sections, and must
be inserted between the head and foot stocks after they have been adjusted to the
proper position. These water guards are usually telescoped or lapped one upon
the other to a certain extent, but in all cases they must be removed and replaced
in position in changing the adjustment of the centres for different lengths of
work. Moreover these guards are not perfectly water-tight, and a small amount
of water and dirt works through upon the grinding surfaces and is liable to
destroy the accuracy of the centres when they are adjusted for a different length
of work.
A further object of the invention is accordingly to provide a table so constructed
that the guiding surfaces are fully protected from water and dirt without the
use of guards which must be removed and replaced for different lengths of work.
A further object of the invention is to provide means for obtaining accurate
adjustment of the slide upon which the grinding wheel is mounted. In machines
for accurate grinding, this slide must be moved in ordinary use as little as one
eighth of one thousandth of an inch, and many times as little as one twentieth
of one thousandth of an inch, and these small adjustments, as well as the larger
adjustments, must be made accurately and be maintained as any error in adjust-

page_text: ment of the slide produces double such error in the work. The slide must also
be heavy to prevent vibration of the revolving wheel, and to move this heavy
weight the small amounts necessary for accuracy of work requires that all con-
ditions of friction and oil be the best, and that there be no torsion in the connec-
tions between the indexing wheel and the slide on which the grinding wheel
is mounted. Even in cases where by reason of favorable conditions and great
care the required accurate adjustment of the wheel slide is obtained, the jarring
of the floor or machine will often cause the slide to advance from one twentieth
to one quarter of a thousandth of an inch causing the wheel to cut the work too
small. In fact, it is very seldom that an operator will succeed in moving the
wheel slide accurately to these delicate measurements, but must usually move
it less than desired to insure against cutting the work too small, and then by
very skillful jarring of the index wheel obtain as near as possible the desired
adjustment. Again, when it is is desired to move the wheel a definite amount
by the aid of the index wheel with its graduations, it is nearly impossible to
find the exact point where all backlash is taken up and the slide really begins to
move.
A
I have found by experiment that even when all connections between the
grinding wheel slide and index wheel are the best yet the oil on the revolving
and thrust bearings of these connections will yield and store up energy enough
to cause a horizontal slide to move uncertain amounts; even though the sliding
contact be very loose and the slide is floating freely on the best oil. In such
a case, also, jars usually cause those slight movements of the slide towards the
work which result in the errors above referred to.
As far as I know previous to my invention all grinding machines were sub-
ject to the errors and objections referred to which it is one of the objects of
my invention to overcome. This I have accomplished by placing the grinding.
wheel slide upon an incline sufficient to cause it to slide down the incline by
gravity even when the conditions of friction and oil are not the best. With
this construction a part of the weight of the slide is transferred from the sliding
surface to the bearings of the moving connections where it is more easily carried
and the friction upon the sliding surface is reduced. Moreover with this con-
struction the slide rests firmly upon its moving mechanism and it is possible
to allow the sliding contact between the slide and its support to be very loose
and to float the slide freely upon oil, and a jar can cause no movement of the
slide towards the work. The torsion of the connections moreover remains prac-
tically wound up or constant so that any perceptible movement of the index
wheel either way is followed by a corresponding movement of the slide. I find
with this construction I am enabled to grind duplicate work within narrow
limits of accuracy without any skill or caution except to place the index wheel
at the proper graduation thus making it possible for accurate work to be done
by relatively unskilled labor, and also making it possible to use automatic.
graduating or feeding devices for the slide.
A further object of the invention is to provide means for carrying a bearing
block which may be readily swung into or out of operative position and which
does not interfere with the swing of the work or the use of a water guard to pro-
tect the ways on which the head and foot-stocks are mounted. This is accom-
plished by providing an arm which is mounted in a bearing at the rear of the
work centres and in a fixed relation to the support for the wheel slide, which arm
extends over and downward, overhanging the work, and carries the bearing
block at its front end. With this construction the front end of the arm may be
swung up out of the way when not in use or when the work is to be changed, and
is always in position where it can be readily and quickly swung into position to
bring the bearing block against the work in front of the grinding wheel. More-
over by thus mounting the bearing block the use of a water guard is not inter-
fered with nor is the swing of the machine reduced as would be the case with an
arm extending below the work.

page_text: Fig. 1 is a front elevation showing a grinding machine embodying the various
features of invention in their preferred form, and
Fig. 2 is a transverse sectional view.
Fig. 3 is a sectional view showing the overhanging arm and its supporting
bracket.
Fig. 4 is a front elevation of the same, and
Fig. 5 is a sectional detail showing the means for clamping the stocks iii
position.
The
The frame 1 of the machine is provided with ways 2 on which is guided the
longitudinally movable bed 3.
The bed may be operated to carry the work across
the face of the grinding wheel 4, by any suitable and well-known mechanism.
The table for supporting and carrying the head and foot-stocks is mounted on
the bed 3 and is preferably connected therewith by a pivot 6 so that said table
may be adjusted for either straight or taper work in a well-known manner.
table is substantially triangular in cross-section and is provided with a base 7.
which rests upon the upper surface of the bed 3, an upwardly extending front
side 8 and a rear side 9 upon which is formed a longitudinally extending way 10.
The face 11 of this way is substantially vertical and said way is provided with an
upper bevelled edge 13 and a lower bevelled edge 14. The head-stock 15 and
the foot-stock 16 are mounted upon the way 10 and are provided with shoulders 17
which engage the upper bevelled edge 13 and bearing faces 18 which engage the
face 11 of said way. The head and foot-stocks are also provided with clamping.
jaws 19 which are drawn against the lower bevelled edge 14 by bolts 20 and
nuts 21 and serve to secure the stocks in position on the way.
The head and tail-stocks extend forward over the upper edge of the table and
preferably downward below said upper edge so that the work is supported out
of line with the way 10, and any water or grit dropping down from the work
will not strike the said way, but will run down the side 8 of the table and fall
into the trough 22. In order to prevent any water or grit thrown off by the work
or grinding wheel from falling on the way 10 the front side 8 of the table is
preferably extended over and beyond the rear side so that the upper edge over-
hangs the rear side and effectively shields the way 10.
By thus forming the table so that it is substantially triangular in cross section
not only is a permanent water guard provided for the way on which the head
and tail-stocks are mounted, but the shape of the table is such that it will resist
strains by which the tables ordinarily used would be deflected from a straight
line.
By mounting the head and tail-stocks upon a substantially vertical way it will
be seen that a broad bearing surface is provided for maintaining the alignment
of the centres in the direction in which an error will produce the greatest in-
accuracy in the work. Thus it will be apparent that any movement of a centre
out of line horizontally will result in double the error in the work, while any
slight movement out of line vertically will not materially effect the accuracy of
the grinding. With the vertical way having a broad bearing face alignment
horizontally is more accurately maintained than heretofore.
By providing the way with bevelled edges and using a clamp for engaging one
of said edges the pressure of the clamp on the bevelled edge may vary without
materially effecting the pressure between the broad faces of the stock and way
and the danger of error due to unequal pressure upon the oil between said sur-
faces is prevented.
The form of table shown combines all the advantages above set forth, but it
will be understood that tables may be designed which will embody some of said
advantages without embodying all and that such tables would be within my in-
vention, the various features of which are not limited in their scope to construc-
tions in which all said features are present.
The grinding wheel 4 is mounted in the slide 23 in any well-known manner.

page_text: The slide is mounted on an inclined way 24 carried by the frame 1, the inclina-
tion of the way being such that the slide will move down the way by gravity.
A rack 25 is secured to the underside of the slide, and is engaged by a gear 26
which meshes with
a gear 27 secured to a short shaft 28. A worm
wheel 29 is also secured to shaft 28 and is engaged by a
worm 30
secured to a transverse shaft 31 provided with a hand wheel 32 at the front of the
machine. An index wheel 33 is secured to the shaft 31 and turns under a
pointer 34 secured to the frame. The functions effected by mounting the grind-
ing wheel slide upon an inclined way have already been fully set forth and need
not be here repeated.
It will be understood that any suitable means may be employed for operating
the grinding wheel slide, and that the invention is not limited to the mechanism
shown for that purpose. In order that the machine may be adapted for taper
work, it is necessary that the axis of the grinding wheel and the axis of the work
should remain in the same plane whether they are parallel or at an angle to
each other and whatever the position of the grinding wheel slide upon its way.
Means are therefore provided for maintaining the work supporting centres, and
the axis of the grinding wheel in the same plane. In the construction shown
this is accomplished by providing the bed, on which the work supporting table
rests, with an inclined upper surface parallel to the way on which the grinding
slide is supported.
An arm 35 is mounted in a bearing 36 formed in a bracket 40 which is secured
to the support on which the grinding wheel slide is mounted, and bears a fixed
relation to the ways on which said slide is mounted. The front end of the arm
when in operative position extends over and downward in front of the work
centres and is provided with guides 41 for supporting and guiding a bearing
block 37 which may be adjusted in said guides by a screw 42. The overhanging
arm may be clamped in its bearing by any means as by the binding bolt 43.
When the bearing block is in use, the arm is swung down into the position
shown in Figs. 3 and 4, with the bearing block in position in front
of the grinding wheel, and said block is adjusted by the screw 42 to engage
and steady the work 44. When the bearing block is not in use, or when the work
is to be changed, the arm may be swung up out of the way, but where it may be
quickly and conveniently thrown into operative position.
A tool socket 38 is preferably formed on the foot-stock in which socket a
truing tool may be held by a set screw 39 and the grinding wheel sharpened or
trued without removing the work from the centres."
While the invention has been shown and described in connection with a machine
in which the work is fed across the face of the grinding wheel and in which the
work centres are adjusted for taper work, it will be understood that the invention
may be applied to those machines in which the grinding wheel travels longitu-
dinally, or to those in which the grinding wheel travels and in which the longi-
tudinal ways for guiding the grinding wheel support are adjusted for taper work.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is:-
-
1-In a grinding machine, the combination with the grinding wheel support,
of a support for the head and foot-stocks having an upwardly extending front
side, a way upon the rear side of said support, and head and foot-stocks mounted
on said way and extending forward over the upper edge of the support, substan-
tially as described.
2-In a grinding machine, the combination with the grinding wheel support,
of a support for the head and foot-stocks having an upwardly extending front side
provided with an overhanging upper edge, a way upon the rear side of the sup-
port under said overhanging edge, and head and foot-stocks mounted on said way
and extending forward over said edge, substantially as described.

page_text: 3-In a grinding machine, the combination with the grinding wheel support,
of a table having an upwardly extending front side, a way upon the rear side of
said table having upper and lower bevelled edges, and head and foot stocks
mounted upon said way, substantially as described.
4-In a grinding machine, the combination with the grinding wheel support,
of a table having an upwardly extending front side provided with an overhanging
upper edge, a way upon the rear side of the table under said overhanging edge,
and head and foot stocks mounted on said way and extending over and below
said upper edge, substantially as described.
5-In a
grinding machine, the combination with the grinding wheel support,
of a table substantially triangular in cross section, a longitudinal way on the rear
side of said table, and hand and foot stocks mounted on said way, substantially
as described.
6-In a grinding machine the combination with the grinding wheel support,
of a table substantially triangular in cross section, a longitudinal way upon the
rear side of said table, and head and foot stocks mounted upon said way extending
forward over the upper edge of the table, substantially as described.
7-In a grinding machine, the combination with the grinding wheel support,
of a table substantially triangular in cross section and having the front side
extending over and above the rear side, a longitudinal way upon the rear side
of said table, and head and foot stocks mounted upon said way and extending
forward over the upper edge of the table, substantially as described.
8-In a grinding machine, the combination with the grinding wheel support,
of a table, a substantially vertical way extending longitudinally of said table,
and head and foot-stocks mounted upon said way, substantially as described.
9 In a grinding machine, the combination with the grinding wheel support,
of a table, a substantially vertical way extending longitudinally of said table and
having upper and lower bevelled edges, head and foot stocks mounted upon said
way, and clamps upon said head and foot stocks for engaging the lower bevelled
edge, substantially as described.
10 In a grinding machine, the combination with the head and foot stocks for
the work centres, of a grinding wheel slide, an inclined way upon which said
slide is mounted, means for moving said slide on said way, and means for main-
taining the work centres and the axis of the grinding wheel in a plane parallel
to said way, substantially as described.
11 In a grinding machine, the combination of a grinding wheel slide, an
inclined way upon which said slide is mounted, means for moving said slide on
said way, a bed having an upper surface parallel to said way, a table pivoted upon
said surface and head and foot stocks mounted in said table, substantially as
described.
12 In a grinding machine, the combination of a grinding wheel slide mounted
on an inclined way, means for moving said slide on said way, a bed having an
upper surface parallel to said way, a table substantially triangular in cross sec-
tion pivoted on said upper surface, a way on the rear side of said table, and head
and foot stocks mounted on said way and extending forward over the upper edge
of said table, substantially as described.
13 In a grinding machine, the combination with a table, head and foot stocks
supported on said table, a grinding wheel slide, an overhanging arm mounted
in the rear of work centres and having its front end located in front of said
centres and a bearing block carried by said arm, substantially as described.
14 In a grinding machine, the combination with a table, head and foot stocks
supported on said table, a grinding wheel slide, a bearing in the rear of the head
and foot stocks and in fixed relation to the support for the grinding wheel slide,
an arm mounted in said bearing and having its front end extending over and
downward and provided with means for supporting a bearing block, substantially
as described.
15-Means for securing a truing tool upon one of the stocks of a grinding

page_text: machine whereby the grinding wheel may be trued without removing the work,
substantially as described.
16 The tail-stock of a grinding machine provided with a tool socket for hold-
ing a truing tool, substantially as described."
BACCE VILIS
Ten day 01 January 1899.
CHARLES HOTCHKISS NORTON.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
CHARLES HOTCHKISS NORTON.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.