Improvements in Machines for Cutting Cycloidal Surfaces.
Year: 1893

page_text: Date of Application, 23rd May, 1893—Accepted, 1st July, 1893
COMPLETE SPECIFICATION.
Improvements in Machines for Cutting Cycloidal Surfaces.
I, JOHN THOMAS WILKIN, of Connersville, in the County of Fayette, and
State of Indiana, 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 :-
My invention relates to a machine for cutting cycloidal revolvers for rotary
blowers, and pumps, gear-teeth etc., and that particular class of revolver employing
two or more lobes.
As is well known to those familiar with this art and having practical experience,
the two-lobe revolver employing what might be termed hypocycloidal and
epicycloidal lines possesses many advantages, especially in the construction of
blowers, in that the revolvers may be constructed and adapted so as to always
revolve-in.contact..
The difficulty heretofore in the employment of these revolvers, though their
virtue was well known, was the cost of their manufacture, and hence they have
been practically abandoned in the manufacture of pumps, blowers, gear-teeth and
the like.
The object of my invention is, primarily, to produce a machine that will
accurately and with facility cut or plane these cycloidal revolvers, and thus reduce
their cost so as to render their use practicable.
Various other objects of the invention will appear in the following description,
and the novel features thereof will, he particularly pointed out in the claims.
Referring to the drawings:
Figure 1 is a side elevation of a machine constructed in accordance with my
improvements and adapted to practice my invention.
Figure 2 is a plan view of the machine.
Figure 3 is an end elevation.
Figure 4 is a vertical transverse section of one of the end standards of the
machine, the parts being in the position they occupy when the machine is adapted
for cutting epicycloidal curves.
Figure 5 is an outer side elevation of one of the standards, the gears and shafts
being removed.
Figure 6 is a similar view, the gears being in position and the gears broken away
to expose the inner gears of the series.
Figure 7 is an inner side elevation of the standard shown in Figure 5.
Figure 8 is an external view in elevation of the segmental gear.
Figure 9 is an opposite elevation of the same and the pinion for operating
the same.
Figure 10 is a diagram intended to illustrate the cycloidal curves cut by my
machine:
Figure 11 is a section similar to Figure 4 with the exception that the gears are
arranged in the position they occupy when the machine is cutting bypocycloidal
curves.
Figure 12 is a view similar to Figure 5, the gears and shafts being removed;
but the parts being otherwise in the positions they occupy, as illustrated in
Figure 11.
Like numerals of reference indicate like parts in all the figures of the
drawings.
In order that I may fully explain the formation of the surface or curve to be
produced by my invention I make the following statement, calling attention to
07

page_text: Fig. 10 of the drawings wherein I have shown two cycloidal revolvers as a matter
of illustration in operative contact. In this figure, 1 designates the center of motion,
and 2 is the pitch-circle. Equal chords 4-4 are drawn within the pitch-circle
forming an exact square. This having been done it is simply necessary to revolve
a circle 3, which is one-fourth the diameter of the pitch-circle, over the pitch-line
of the pitch-circle between the opposite angles formed by the chords beginning and
ending exactly at said angles, and the lines described by the scribing-point of the
circle 3 which will be in its circumference, will form the opposite epicycloidal
lobes.
Now by arranging the same size circle inside the pitch-circle and revolving from
angle to angle of the opposite chords, as before described, the line scribed by the
scribing-point of the circle 3 will constitute the hypocycloidal curve. In the same
manner and upon the same principle revolvers having a greater number of lobes
may be formed, for instance a three-lobed revolver would be formed by first
scribing the pitch-circle, next forming a hexagon by means of six chords drawn
upon the circle, and scribing lines between the angles of the chords by means
of the circle one-sixth the diameter of the pitch-circle and alternately at opposite
sides of said circle, as will be obvious.
Having described the principle upon which the cyclodial lines are formed, I will
now proceed to describe my improved machine :
The general frame-work of the machine comprises a pair of opposite sides or
standards 5 preferably cast and surrounded by a heavy flange 6, the whole being
bolted securely to a base or sill 7. As each of these standards or sides is a counter-
part of the other, a description of one will be sufficient for both, and I will therefore
confine myself in my description to a single standard. The standard is provided at
a point slightly above its transverse center with a circular opening 8, and above the
same with a bearing 9 while vertically below said opening a larger bearing 10 is
formed. These bearings 8, 9, and 10, are in direct vertical alignment, and are
surrounded by a thick flange, as shown. The bearing 10 is merely a half-bearing
and is provided at opposite sides with shoulders 11, against which abut the ends of
a companion bearing-block 12 that is removably slid into the open side of the
bearing 10 and is held in place by means of a pair of bolts or screws 13 which pass
through the projecting ends or flanges of the bearing-block and into the edges of
the standard 3. The block is further provided with a handle 14 by which when
the screws are removed, said block may be withdrawn from its position.
Transversely opposite the opening 8 in the standard the flange surrounding the
edge of the same is removed partially and from the edge there projects rearwardly
an arm 15 integrally formed with the standard and provided at its outer extremity
with a bearing-opening 16, and near the standard with a second bearing opening 17,
the same being in horizontal alignment with the opening 8 in the standard. The
standard is further provided with a bearing-opening 18, the same being in alignment
with the three openings 16, 17, and 18.
In the bearing-opening there is located a short shaft 19, the same having its
inner end threaded and provided with a nut 20, while beyond the standard the
shaft is provided with a collar or boss 21, whereby it may be clamped snugly in
position. It is further held in position by means of a binding bolt 22 passed
down through a threaded perforation formed in the upper end of the standard and
at its lower end bearing upon the shaft. Beyond the collar 21 the shaft is
slightly greater in diameter, in this instance, than that portion within the standard,
and it is provided between its collar and outer end with an inner and an outer
annular groove designated as 23 and 24 respectively. Upon this shaft is mounted
for rotation a spur-gear 25, and through the hub of the same a bolt or screw 26
is passed, the same being designed to engage at its lower end with one or the
other of the grooves 23 or 24. A retaining-plate or cap 27 is located at the
outer end of the shaft 19 and the same is held in place by a screw 28 passing
through the cap and into the end of the shaft. It will be seen that by loosening
the screw 26 the spur-gear may be moved in or out upon the shaft and locked

page_text: for revolution at such point by engagement of the screw with the grooves 23 or 24,
as the case may be.
Mounted for rotation in the large opening 8 is a ring 29, and the same is provided
with an eccentrically located bearing-opening 30. The ring is provided at one
side of its bearing-opening with a recess 30 in which is mounted a bolt 30° pro-
vided with a flange 30° near its lower end, between which and the outer contracted
mouth of the recess 30 there is coiled upon said bolt a spring 30d, the tendency
of which is to force the bolt into the opening 30. The inner edge of the ring is
preferably provided with a surrounding annular flange 31, while its outer edge
within the standard is provided with a series of teeth 32 which register or are in
line with the recessed flange surrounding the standard and the opening 8. Located
in the aforesaid eccentric opening 30 is a sleeve 33 whose inner end extends beyond
the inner face of the standard and is there enlarged' and provided with teeth
forming an integral pinion 34. The sleeve and ring are provided with registering
openings or perforations between their opposite ends, that of the ring being
threaded while that of the sleeve is plain, and in the threaded perforation of the
sleeve there is inserted a screw 35 whose lower end is plain and tapered and takes
into the perforation of the sleeve 33, whereby the sleeve and ring are locked
against any independent movement and must move together. Mounted for rotation
in the sleeve 33 is a shaft 36 whose outer end beyond the standard and sleeve is
slightly reduced as at 37 and receives a pinion 38, the diameter of which is the
same as that of the pinion 34, which as will be seen, is located also upon the
shaft 36 but at the opposite side of the standard.
The inner end of the shaft 36 is provided with a crank-arm 39 and at its free
end carries a crank-pin 40 the length of the arm being the same as the radius of
the pinions 34 and 35. The shaft 36 in line with the longer end of the crank-
arm 39 is provided with a cavity 36ª. It will be seen that the diameter of the
wheel 25 is of no importance, that is, compared with the diameter of the pinions 34
and 38, but it is necessary that the lower teeth of the pinion 38 and the lower
teeth of the gear 25 should be in horizontal alignment when the ring 29 is so
arranged as to bring its bearing-opening 30 in its uppermost position, as shown in
Figs. 4 and 5 of the drawings.
Mounted for rotation in the bearing-opening 10 of the standard is a sleeve 41
the same having its outer end projecting some distance beyond the outer face of
the standard, and is provided adjacent to the standard with an external boss 42.
Beyond the boss the sleeve is provided with a key-seat 43 and mounted upon and
for rotation with the sleeve is a spur-gear 44 also provided with a key-seat 45
which registers with that of the sleeve. A spline 46 is located in the seats of the
sleeve and the gear so as to lock the two together, and a binding-screw 47 passes
through a perforation in the hub of the gear and bears upon the spline. The
sleeve 41 is slightly reduced or tapered internally toward its inner end.
Located in the bore of the sleeve is a tubular externally-tapered bushing 48, the
same being slightly longer than the sleeve and having its inner end projecting
beyond the same and externally threaded as indicated at 49. The inner end of the
bushing is encompassed by a binding-cap or nut 50, said cap having an opening
coinciding with that of the bushing.
Stub shafts 51 and 52 are located in and extend from the openings 17 and 18
heretofore described as being formed in the arm 15 and the standard, each of said
shafts being stationary. That shaft 53 located in the outer bearings 16 of the
two arms 15 extends entirely across the framework thus connecting the two
standards 5. The shaft 53 is provided with a hand-wheel 54 by which it may be
revolved. The extremities of the shaft 53 beyond the arms 15 carry spur-gears 55
that revolve with the shaft and these spur-gears engage with gears 56 which are
mounted respectively upon the shafts 51 and 52, the inner spur-gear of the series
engaging with the teeth 32 of the rotatable shifting-ring 29.
Each of the standards 5 near its lower end and near one edge is provided with a
bearing-opening 57 and in the same is journalled a shaft 58, the same like the

page_text: shaft 53 serving to connect the two standards and projecting beyond the outer
.sides thereof. Upon this shaft is mounted beyond the standards at one side an
inner spur-gear 59 and an outer worm-gear 60, while at the opposite end but the
single spur-gear 59 is located. The inner spur-gear 59 engages with the lower
spur-gear 44 at that side of the machine, and serves to transmit motion through
the same to the gear 25 and to the pinion 38 when the latter is elevated or in its
uppermost position (as shown in Fig. 4) wherein the machine is designed to cut the
epicycloidal curve. But on the other hand, when the gear 38 is in its lowermost
position for cutting the hypocycloidal curve, the motion is then imparted to the
pinion 38 through the spur-gear 25. Rising from the sill and bolted thereto just
beyond the worm-gear 60 is a vertical bearing standard 61 and in the same is
journalled a vertical shaft 62 provided at its upper end with a hand-wheel 63 and
near its lower end with a worm-screw 64 which engages with the aforesaid worm-
gear 60.
65 designates a segmental, internally-toothed gear the same being substantially
L-shaped in cross section and having its vertical wall provided with an opening 66.
Two of these gears are provided, one for each of the crank-pins 40. The toothed-
portions of these gears engage with the pinions 34 and being twice the pitch-
diameter of the stationary pinion 34, when the crank-arm 39 revolves the said
segmental gear changes contact continually, the point of contact between the
gear 34 and the segmental gear 65 being always in direct longitudinal alignment
with that of the crank-arm 39. The outer face of the vertical wall of the
segmental gear is provided with a circular dovetail groove 67.
Upon each of the crank-pins 40 is mounted a standard 68, the same having an
opening 69 at its lower end for the aforesaid crank-pin. At diametrically-opposite
sides of the arm and the opening 69 the arm is reduced to form lugs 70, and these
lugs are provided with perforations 71, through which are passed bolts or pins 72
whose inner ends or heads take into the circular dovetail groove 67 and whose
outer ends beyond said lugs are provided with nuts 73 whereby said bolts or pins
may be tightened within the grooves and thus the standards securely locked at
opposite sides of the crank-pins to the segmental gears. The standards support at
their upper ends an ordinary carriage-way or frame 74 on which is mounted for
movement a carriage 75, the same being designed to carry a tool 76. The
carriage is fed by the usual threaded feed-rod 77, which receives motion through a
train of gearing 78 by means of which the tool is reciprocated back and forth upon
the way.
Above the machine is located an ordinary tension mechanism for driving the
tool-carriage, and so constructed as to permit of a swinging of the same.
At one side of the base of the machine there is located a pair of vertical
standards 79, the same being provided at their upper ends with yokes or
recesses 80. These standards are provided at their ends with adjustable rest-
screws 81 which support the tool-carrying mechanism when the end of its swing or
travel is reached and the machine is to be adjusted for the cutting of an opposite
or contrary cycloid. The standards 79 it will be observed are pivoted at their
lower ends at 82 to the base or sill, so that they may be swung down flush with or
below the plane of the sill to permit of the introduction of the work or blank to the
machine.
83 designates a blank upon which the machine is in the act of operating, as
shown in Fig. 1, and it will be observed that the same has an axial-shaft 84, the
diameter of which is the same as the bore of the tapered bushing 48 and the
opening in the binding-nut or cap 50.
To introduce the work, as before intimated, the standards 79 are swung to a
horizontal position and the bearing-blocks 12 withdrawn from the standards, for
which purpose the screws 13 are partially removed. After the blocks 12 have
been removed, the sleeves together with their bushings, and the spur-gears 44 are
removed from the openings 10 and the inner ends of the bushings slipped over the
ends of the shaft 84 after which the parts are replaced, the blocks placed in position,

page_text: the screws 13 tightened and the caps or nuts 50 run down upon the bushings
drawing the same inwardly and setting or clamping the shaft.
The work having been placed in position in the machine the standards 68 are
swung upon the crank-pins 40 until the tool-carriage and its support rest upon the
screw-rests 81. The tool is now started and a gradual feeding of the work and
also of the tool is accomplished by a gradual rotation of the hand-wheel 63 the
motion being conveyed in the manner heretofore described and as will be obvious.
Assuming the crank-shaft to be in an elevated position as shown in Fig. 4 it will
be seen that the tool when the same has reached the end of its feed, that is where
the crank has travelled from the rest-standards to the opposite side of the machine,
its movement will be arrested by reason of the spring-bolt 30 engaging with the
cavity 36 in the crank-shaft 36, and this arrest of movement will be at the com-
pletion of the curve. Having formed the epicycloidal surface upon the work the
following shifting of the parts takes place :
The set-screws 47 are loosened and the spur-gears 44 slid outward upon the
sleeves 41 until their inner faces are slightly beyond the outer faces of the
pinions 38 when the hand-wheel 54 is revolved and through the medium of
-the-gears_55_and_56 motion is imparted to the ring 29 and the same is revolved
until its bearing-opening 30 is diametrically opposite -the-position-it previously_
occupied or in other words is vertically below the centre of the ring. That
brings the upper side of the pinions 38 in the same plane as the upper side of the
spur-gears 44. The set-screws 26 are now loosened or withdrawn from the annular
groove 24 of the shaft 19, and the spur-gears 25 slid inward upon the shafts 19 and
the set-screws run down into the grooves 23 of the shafts 19.
Thus it will be seen that the two gears 25 engage with the gears 44 and the
pinions 38 and the same result is obtained as if internal gears were substituted for
the spur-gears 44.
Previous to the partial rotation of the eccentric ring 29 the nuts 73 of the
bolts 72 are loosened. It will be seen that when at the end of its movement the
crank-pin will be at its lowest position, and after the nuts 73 have been loosened
on the bolts 72 and the eccentric ring 29 swung or partially rotated so that its
bearing-opening is in the lower position, the said bolts will have changed position
upon the segmental gear, whose position is now reversed to that shown in Fig. 4.
In Fig. 8 I have described the position of the segmental gear when the
crank-pin is lowered, and in Fig. 9 I have illustrated the same when the crank-pin
is elevated.
Having retightened the bolts and the parts having been placed in the positions
described, the machine is now ready to cut the hypocycloidal surface, the operation
being the same as that before described, and the crank-shaft revolving once iu
cutting the curve, when the machine is ready for repeating the operation.
The eccentric ring 29 is provided in its periphery at opposite sides of its center
with cavities 85 and at one side of the opening 8 in the standard a radial bore 86
is provided. In this bore a spring-pressed pin 87 is located, the inner end of the
pin extending into the opening and being designed to engage with either one of
the cavities 85. By such means it will be seen that in revolving the ring to change
the location of the shaft 36 and its gear or pinion, the ring will be stopped or its
motion arrested at the proper point, or directly as the said shaft reaches a point
vertically below its former position.
From the foregoing description, in connection with the accompanying drawings,
it will be seen that I have provided a simple mechanism capable of producing with
facility the advantageous form of revolvers, whose virtues, though heretofore
recognized, have been lost by reason of the extreme difficulty accompanying their
manufacture.
I do not limit my invention to the details of construction shown and described
but hold that I may change the same at will without departing from the spirit or
sacrificing the advantages thereof.

page_text: 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. In a machine of the class described, the combination with opposite supports,
meaus for supporting a blank between the same, of a tool-carrying device, means
for reciprocating the same longitudinally of the blank and transversely feeding it
upon cycloidal lines substantially as specified.
2. In
a machine of the class described, the combination with means for
supporting a blank, of a tool-carrying device located adjacent thereto, and means
for moving the tool upon cycloidal lines over the face of the blank, substantially as
specified.
3. In a machine of the class described, the combination with the opposite side
frames provided with bearings, a blank-carrying shaft mounted for rotation therein,
and means for revolving the shaft, of a superimposed tool-carrying device, means
for reciprocating the device between the side frames, and means for transversely
feeding the device upon cycloidal lines to the blank, substantially as specified.
4. In a machine of the class described, the combination with the opposite side
frames having bearings, a transverse revolver carrying shaft mounted therein, tool-
carrying devices located above the shaft, means for reciprocating the devices, for
rotating the shaft, and for moving the tool-carrying devices upon hypocycloidal and
epicycloidal lines to the blank, substantially as specified.
5. In a machine of the class described, the combination with the opposite side
frames, and the blank supporting shaft, a superimposed tool-carrying device, means
for reciprocating said device between the frames, and for feeding the same in
cycloidal lines to the blank, substantially as specified.
6. In a machine of the class described, the combination with the opposite side
frames having bearings, a transverse blank-carrying shaft mounted in opposite
bearings therein, means for revolving the shaft, of a crank-shaft for each of
the standards, standards rising from the crank-shafts, a tool-carrying bar con-
necting the standards, and means for revolving the crank-shafts, substantially as
specified.
7. In a machine of the class described, the combination with a framework
having openings, rings mounted, in the openings and provided with eccentric
bearings, crank-shafts journa!led in the bearings, pinions mounted upon the shafts
at the opposite sides of the frame, segmental gears carried by the cranks of
the shafts and engaging the inner pinions, a tool-carrying frame secured to
the segmental gears, of a support for the work, shafts located at one side of the
crank-shafts, gears mounted adjustably on the shafts and adapted to engage the
outer pinions, means for driving the gears, shafts at the opposite sides of the crank-
shafts, gears mounted on the same and engaging the other gears, and means for
adjusting the gears thus engaging, and for rotating the rings, substantially as
specified.
8. In a machine of the class described, the combination with the opposite frames
having circular openings, rings mounted in the openings and having eccentric
bearings, crank-shafts mounted in the bearings, tight pinions carried upon the
outer ends of the crank-shafts, stationary pinions encircling the inner portions of
the crank-shafts, segmental gears internally-toothed and mounted upon the crank-
pins and having their teeth engaging the inner pinions, standards loosely mounted
on the crank-pins, circular grooves formed in the outer faces of the segmental gears,
bolts passed through the standards into the grooves, nuts mounted on the bolts and a
tool-supporting frame carried by the standards, of upper and lower bearings formed
in the frames, shafts located in the upper bearings, spur-gears mounted adjustably
on said shafts, shafts located in the lower bearings, spur-gears adjustably mounted
on said shafts and adapted to engage the teeth of the upper spur-gears and of the
outer pinions when the latter are in their elevated positions, and means for rotating
said lower gears, substantially as specified.

page_text: 9. In a machine of the class described, the combination with opposite frames.
having circular openings, rings mounted in the openings and having eccentric
bearings, crank-shafts mounted in the bearings, pinions fixed on the outer
ends of the crank-shafts, fixed pinions encircling but independent of the inner
portions of the crank-shafts, segmental gears internally toothed and mounted
upon the crank-pins and engaging the inner gears, means for temporarily
arresting the motion of the crank-shaft at each rotation thereof, shafts located
diametrically opposite the crank-shafts and extending beyond the outer ends.
thereof, gears adjustably mounted upon said shafts and intermeshing with each
other and adapted to intermesh with the pinions upon the outer ends of the crank-
shafts, and means for rotating said gears, substantially as specified.
10. In a machine of the class described, the combination with the opposite frames
having circular openings, rings mounted for rotation in the openings and provided
with eccentric bearing recesses formed at one side of the bearings, pins mounted in
the recesses and provided near their inner ends with shoulders, coiled springs
mounted upon the pins and interposed between the shoulders and the outer ends of
the recesses, crank-shafts journaled in the bearings, pinions mounted fixedly on the
outer ends of the crank-shafts, fixed pinions extending from the inner sides of the
frame and loosely encircling the crank-shafts segmental gears loosely mounted on
the crank-pins and internally toothed to engage the said fixed pinions, a tool-
carrying-frame-supported-by-the-segmental-gears,_and_cavities_formed_in_the_
crank-shafts in line with the pins, of shafts located at diametrically opposite.
sides of the crank-shafts, adjustable gears mounted thereon and engaging each
other and adapted for engagement with the outer pinions of the crank-shafts in
accordance with the positions of the same, and means for rotating the gears,.
substantially as specified.
11. In a machine of the class described, the combination with a framework
having opposite openings, movable bearings mounted in the openings, crank-shafts
mounted in the bearings and adapted to revolve, pins located upon said shafts at.
the inner and outer sides of the bearings, segmental L-shaped gears mounted on
the inner or cranked ends of the shafts, and a tool-carrying frame secured to and
supported by the segmental gears, of a support for the work, shafts located at one.
side of each of the crank-shafts, gears mounted thereon and adapted to be shifted
into and out of mesh with the outer pinions of the crank-shafts when the latter are
lowered to their lowest positions and in a horizontal plane with said pinions when
said crank-shafts are elevated to their highest positions, gears located at those sides
of the outer pinions of the crank-shafts at which the first mentioned gears are
located, means for shifting and driving said gears and for communicating motion
from them to the work-support, substantially as specified.
D
..ו
2011 SM 1902
W. P. THOMPSON & BOULT,
Agents for the Applicant.