Improvements in Grinding or Abrading Machines.
Year: 1893

page_text: Date of Application, 21st Mar., 1893-Accepted, 14th Oct., 1893
COMPLETE SPECIFICATION.
Improvements in Grinding or Abrading Machines.
I, DUANE HERBERT CHURCH, of Lenox Street, West Newton, in the County
of Middlesex and State of Massachusetts, United States of America, Gentleman,
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 this invention is to produce a means for grinding the periphery
of disks, to make them of a uniform diameter. The invention is particularly
adapted to the grinding of watch-dials, and consists of a means for automatically
compensating for the wear of the grinding-surfaces, and so adjusting them relatively
to the dial-holder as to cause each dial to be ground of exactly the same diameter,
regardless of the wear of said grinding-surfaces caused by the previously-ground
dials.
In order that the invention may be fully understood, I will proceed to describe it
with reference to the accompanying drawings, of which,-
Figure 1 represents a plan of a machine constructed according to my invention.
Figure 2 is a front elevation, partly in section.
Figure 3 is an end elevation.
Figure 4 is a vertical cross-section, taken through the middle of the machine, but
showing the dial-holder in elevation.
Figure 5 shows a horizontal section.
Figures 6 and 7 show details.
The same letters of reference indicate the same parts in all the figures.
The frame of the machine consists of a bed 1, supported by legs 23. Mounted
on the bed 1 are slides 5 6, constructed to carry and support shafts 7 8, provided at
their inner ends with holders 9 for carrying the substance desired to form the
grinding-surface. In the present case, it is desired to use emery laps 10 for this
purpose, which serve at the same time as housings to confine any dust or particles
removed during the grinding operation.
Beneath the grinders is a pan p, from which extends a duct d, for receiving and
carrying off water which is supplied during the grinding operation.
Mounted on the bed 1 is a standard 14, which supports and carries the dial
holding and operating devices 12 13, which are or may be of any suitable con-
struction. When used for grinding watch-dials, it is preferred that the holding
device 12 13 be obliquely disposed in relation to the shafts 7 8 to an extent
corresponding to the desired bevel to be given to the periphery of the dials.
The dial-holder is pivoted at 67, so that it may be raised and lowered in removing
and replacing the dials, and provision is made for cushioning the up and down
stroke, as follows: The holder is connected by a vertical rod 68 with a piston 69
in an air-cylinder 70. A plunger-rod 71, connected with said piston, extends out
of the bottom of the cylinder, and connects with a treadle or other suitable power-
applying agent. A spring 72 bears at one end against a shoulder 73 on the
plunger-rod, and at the other end against the cylinder 70, whereby it cushions the
upward stroke of the plunger-rod. The return or downward movement of the piston
is cushioned by the air in the cylinder.
Shafts 78, together with holders and laps 10, are driven from any desired
source by pulleys 15 16 respectively.
Mounted in carriages 60, on the under side of the bed 1, are two vertical
shafts 17, provided with arms 18 19 at their upper and lower extremities
respectively. The arms 18 extend inward (between the grinding-surfaces 10) and
are provided on their extremities with diamond stops 18¹, and said arms 18 are

page_text: placed to bring the stops 18 at a distance apart corresponding with the desired
diameter of the dial to be ground. Thus the stops act as a caliper for measuring
each dial, for the grinding of the dial continues until the faces 10 come in contact
with the stops '18, at which point the grinding ceases, as hereinafter explained.
The arms 19 are normally in electrical contact with electro-magnets 191, and are
separated from the latter to break the connection by the contact of the stops 18'
with the grinding-surface 10.
The carriages 60 are connected together by a rod 61, having right and left hand
screw-threads engaging the carriages respectively, whereby, when the said rod is
turned in one direction, the carriages will be moved toward each other; and, when
said rod is turned in the opposite direction, the carriages are moved away from
each other. Thus, by turning a knob 62 on the end of said rod, the arms 18 may
be adjusted for dials of different diameters. Each of the carriages is provided with
a screw 63, which projects through a slot in the bed 1, and has a head 64, whose
under side is pressed by a flat spring 65 in a groove on the bed. By this means,
accidental displacement of the carriages after adjustment is prevented.
The electro-magnets 19' are carried by the carriages 60, and hence the relation
between them and the arm 19 is not disturbed by adjustment of the carriages.
The slides 56 have a longitudinally reciprocating motion, moving simultaneously
toward and away from each other. The movement of the slides is effected through
the instrumentality of sleeves 641, mounted to turn in bearings in the bed 1, and
engaging screws 65¹ on the slides. Gears 73 are fixedly mounted on the
sleeves 64', and they mesh with gears 74 mounted on a counter-shaft 75. These
latter gears 74 have a frictional connection with the said counter-shaft, whereby
they may under certain conditions turn independently thereof. Each of the said
gears is held between discs 76, keyed to the shaft, and faced with a material
such as leather so as to create friction between them and the gear. One of
these discs is spring-pressed against the gear, as shown in Figure 5. Motion is
transmitted from the driving-shaft 77 to each of the gears 74, through the following
described mechanism. A hollow shaft 78 is supported in stationary bearings, and
carries a gear 79, meshing with the gear 74, and one member 80 of a friction
cone-clutch, the other member 80 of which is mounted on the driving-shaft. The
shaft 78 is permitted a slight end wise movement to lock and release the clutch.
A rod 81 occupies the bore of the shaft 78, and is pressed against the end of the
driving-shaft by a spring 82, bearing at one end against the rod and at the other
end against a screw 821 fastened in the end of the shaft 78, whereby said spring
tends to separate the members of the clutch. The member 80¹ of the clutch
contains an electro-magnet 83, and the member 80 constitutes an armature to be
acted upon by said magnet and drawn into frictional engagement with the
member 80¹.
The main shaft 77 is continuously driven through any suitable means, such as
worm 84 and gear 85.
The machine may be wired in any suitable manner so that an electrical circuit
may be established through the magnets 83, and the gage devices may constitute
switches by which to cut said magnets in and out.
In the present instance, a source of electricity, as a battery, is indicated at 86,
and connected with the magnets 191 and 83 respectively. The maguets 83 being
rotary parts, the connection is a sliding one, consisting of an electrode 87, contacting
with an annular surface 88 of the magnet-casing. The circuit is completed by
connecting the arms 19 of the gage devices with the magnets 83. As here shown,
this connection is indicated as being with the clutch parts or armatures 80.
The extent of normal movement of the grinders, according to the diameter of
dial desired, is regulated by means of a disc 88', mounted fixedly on the end of the
counter-shaft 75, and a stop-arm 89, fastened at one end to a fixed part of the
machine and arranged to give or yield in one direction only. The disc 881 is pro-
vided with an annular series of perforations 90 and stop-pins 91 and 911 may be
removably inserted in said perforations so as to project from the inner side of the

page_text: disc and encounter the stop-arm 89. A weight is suspended by a flexible
connection 93 from a grooved pulley 94 on the shaft 75, and tends to rotate said
shaft in a direction which will cause the pin 91 to bear against the under side of
the stop-arm 89, as shown in Figure 3. The pin 911 is set to perinit a rotation of
the counter-shaft to the extent necessary for a normal movement of the grinders to.
grind a dial to the desired diameter, the rotation of said shaft being stopped by the
pin 91 encountering the upper side of the stop-arm 89. The impact of the pin 91
against the stop-arm, upon the return of the shaft by the weight is cushioned by
reason of the yielding property of the said stop-arm.
The operation of the machine is as follows, assuming that, imprimis, the
grinding-surfaces 10 10 are fresh and not worn: The machine having been
adjusted to the desired diametrical size of dial, the dial to be operated upon is
placed in the holder 12 13, the slides 5 6 being separated, and the electrical circuit
is established by bringing the arms 19 into contact with the magnets 19', and the
attractive power of the latter will hold the gage devices (comprising the arms 18
and 19) positively in this adjustment, aud prevent accidental displacement. The
magnets 83 now being excited, they lock the clutches, so that the shafts 78 will
turn with the driving-shaft 77. The machine being set in motion, the dial-holder
revolves the dial at the desired speed, and the main-shaft 77, through the
gears 79, 74 and 73, revolves the sleeves 64, and thereby moves the grinders toward
each other, by the engagement of said sleeves with the screws 65. The grinding-
surfaces 10 grind down the periphery of the dial until said surfaces encounter
the stops 181. When this occurs, the dial will have been reduced to the proper
diameter, and the grinding ceases by reason of the arms 18 being moved toward
each other, thereby moving the arms 19 away from the magnets 19' and breaking
the circuit, thus rendering the magnets 83 inactive, and permitting the springs 82
to disconnect the clutch-parts, so that the shafts 78 are no longer rotated by the
driving-shaft 77. Simultaneously with this action, the stop-pin 91' encounters the
arm 89, and stops the counter-shaft 75 which has been rotating with the other
parts. Then the weight runs the grinders back away from each other to their
normal position, ready to act on another dial.
+
The grinding of the first dial removes a portion of the grinding-surface 10,
and hence, in grinding the next dial, in order to bring it to the same diameter
as the first one, the grinders must move toward each other to an extent as much
greater than in the first instance as the amount of grinding-surface worn away
during the grinding of the first dial. When the grinders arrive at the point where
they were stopped in grinding the first dial; the stop-pin 91' encounters the arm 89,
as before, and stops the rotation of the counter-shaft 75. But, by reason of the
reduction in the grinding-surfaces 10, they will not have encountered the stop 18'
when this takes place, hence the electrical circuit remains unbroken, and the
clutches are still locked by the influence of the magnets 83, and the rotation of the
shafts 78 continues, and the grinders are moved further toward each other,
the frictional connection of the gears 74 with the counter-shaft permitting said
gears to continue to turn, while said shaft is held stationary, said gears slipping
between the discs 76. The movement of the grinders upon the dial continues until
the grinding-surfaces encounter the stops 18', when said grinders are stopped and
run back, as before. The second dial now complete, and is of an exact size with
the previously-ground one.
The operation may be continued until the emery laps 10 are completely worn
away, and the discs ground will all be of a uniform diameter.
The machine could be so arranged that the diamond stops 18' would rest upon
the periphery of the disk being ground, and break contact when the desired size
was attained, thus stopping the electrical feed and the forward motion of the
grinding lap. This method could also be applied to the grinding of elongated
cylinders, where a disc lap having a traverse motion from end to end of a cylinder
is commonly used.

page_text: I do not confine myself to the exact means shown and described for taking up
the wear of the grinding-surfaces, as any suitable mechanical means could be
substituted for those shown.
The invention is not limited to the conjoint use of the two grinding mechanisms
here shown, and one of said mechanisms may be omitted without departing from the
spirit of the invention.
It will be seen that the grinders have a normal feed movement, and an additional
compensating feed movement.
It will also be seen that the extent of said compensating feed movement is
determined by an automatic stop device or mechanism, which makes the actuating
mechanism inoperative when the grinding-surface reaches a predetermined position.
I believe myself to be the first to combine with a grinding lap and a feed
mechanism which causes a progressive action of the lap upon the piece to be
ground, of an automatic stop which renders the feed mechanism inoperative when
the piece is reduced to a predetermined size, the feed motion continuing until
the piece reaches said size and then stopping, so that the size imparted to the
piece by the grinding operation is not affected by wear of the grinding lap;
hence I do not limit myself to the details and organization of the said combination
here shown and described.
The mechanism whereby the compensating feed movement and its automatic
arrest may be effected may be variously modified, and I do not confine myself to
the particular organization and details of mechanism here shown.
The invention is not confined to a feed having a normal limit and a compensating
extension thereof, but two separate feeds might be employed, one to supply the
normal movement and the other the supplemental or compensating movement.
Figures 8, 9, 10 and 11, illustrate a construction by which the invention may be
embodied in a machine for grinding elongated bodies. The work as, 100, is carried
on a carriage, 101, mounted in a suitable manner so as to be capable of traveling
back and forth across the grinding lap, 102. This grinding lap is in the form of a
disc which is mounted on a slide, 103. The stop-arm. 104, is carried on an
auxiliary slide, 105, and has a diamond point 106, for contact with the periphery of
the emery-lap, 102. The slide, 105, is mounted to move over the slide, 103, and
the two slides are driven by one screw-shaft, 107, having screw-threads of different
pitch engaging the slides respectively whereby the slide, 105, will move twice as
fast as the slide, 103. The screw-shaft is driven through its primary movement
and through its movement which compensates for the wearing away of the emery-
lap, by mechanism of similar construction and arrangement to that already
described with reference to the other figures.
In view of the fact that an elongated body is under treatment, and to be reduced
to a uniform size throughout its length the grinding lap must be held up against
the work for a certain length of time after the piece has been reduced to the
desired diameter at one end. This may be accomplished by the construction here
shown in which a divided counter-shaft, 108, has its ends frictionally connected by
means of suitably constructed heads, 109, and 110. The head 110, comprises a
drum on which a cord or like flexible device, 111, is adapted to be wound, said cord
having a weight attached to its end, and arranged to turn back the feeding parts
after one piece has been ground. The driving shaft, 112, is connected with the
right hand member of the divided counter-shaft by gears, 113, 114, an electric
friction clutch, 115, being inserted in the driving shaft. A perforated disc, 116, is
fastened on the end of the divided counter-shaft and receives a stop-pin, 117, to
throw the feed parts out of gear with the driving shaft at a predetermined time.
An arm, 118, is journalled on the counter shaft and insulated therefrom, and this
arm is connected by a spring, 119, with the pin, 117, so as to be held in contact
with said pin. Two electro magnets, 120, 120¹ are employed and one of them, 120,
is in a circuit which includes the clutch, 115, and a triple-armed device is employed
to connect said magnets with the arm, 118. Two arms, 121, and, 122, of said

page_text: triple armed device are arranged for contact with the two magnets respectively,
and the third arm, 123, engages the periphery of a hub or boss on the arm, 118.
One circuit is through the disc, 116, pin, 117, arm, 118, triple-arm device, and
the magnet, 120, and the arm, 118, is arranged to encounter the pivot of the triple
arm device and thereby break the circuit, as shown in Figure 11.
It will now be seen that after the primary feed and the wear-compensating feed
has been effected the emery-lap is still held up against the work, as the cord, 111,
is still being wound upon the head, 110, as the latter is driven from the shaft, 112,
through the gears, 113, and, 114, and the frictional contact of the heads, 109,
and 110, prevents the left-hand member of the counter shaft from turning back.
This continues until the arm, 118, encounters the pivot of the triple-arm device,
when the circuit through the clutch, 115, is broken, and the weight on the
cord, 111, then turns back the feed parts, the two members of the counter shaft
turning together, by reason of the frictional engagement of the heads, 109,
and, 110, until the left hand member is stopped in the manner described with
reference to the first form of machine; the right hand member continues to be
turned back by the weight until the pin, 117, in the disc, 116, encounters a stop-
arm, 125, the head, 110, slipping on the head, 109. When the circuit is broken
the arm, 121, drops by gravity, moving the arm, 122, away from the magnet, 120¹,
and the arm, 118, out of contact with the hub of the arm, 123, so that when the
latter is returned against the pin, 117, by the spring, 119, the circuit will not be
made.
The magnet, 120, is in the circuit which includes the stop-arm, 104, and hence
when the machine is started by moving the said stop-arm into operative relation
with the magnet, 124, the magnet, 120', is rendered active and attracts the
arm, 122, thereby making the circuit through the clutch, 115.
It is evident other mechanism might be employed to accomplish the result,
than that here shown and described.
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 :
1st. The combination of a movable grinding device, a feed mechanism which
causes a progressive action of the grinding device upon the piece being ground,
and an automatic stop whereby said feed mechanism is rendered inoperative when
the piece is reduced to a predetermined size, as set forth.
2nd. The combination of a movable grinding device, a feed mechanism which
causes a progressive action of the grinding device upon the work, and electrical
means for controlling the said feed mechanism whereby the latter is rendered
inoperative when the piece is reduced to a predetermined size, as set forth.
3rd. In a grinding machine, the combination of a movable grinding device, a
feed mechanism having a normal limit of action and capable of an additional or
compensating action, and means for automatically arresting said compensating
action when the grinding-surface reaches a predetermined position.
4th. In a grinding machine, the combination of a movable grinding device, a
feed mechanism having a normal limit of action and capable of an additional or
compensating action, electrical means for maintaining the feed mechanism operative,
and a circuit breaker which renders the feed mechanism inoperative when the
grinder reaches a predetermined position.
Dated this 25th day of February 1893.
DUANE HERBERT CHURCH.