Note: Descriptions are shown in the official language in which they were submitted.
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_ kground of the Invention
In the field of center-type cylindrical grinding,
;: machines have hi.storically taken a similarity of design in
. . the arrangement of the essential machine elements. Specifically,
a cylindrical workpiece is carr'ied with its longitudinal
¦axis held in a horizontal plane while it is supported and
rotatably driven about the horizontal axis as a rotatable
~` ! grinding wheel ~also having a horizontal axis) is carried
,into contact with the workp,iece by a wheelhead which is
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1 llqlidable along a horizontal way system. The configuration
2 ~lof the grinding machine has generally been arranged so that
3 an operator may stand at one side of the part while -the
4 grinding wheel approaches from the opposite side of the
part, towards the operator, thus engaging the workpiece at
6 an intermediate point between the operator and the wheel.
7 IAccording?y, interchange of parts has been generally carried
8 out from one side of the part, either by manual inser~ion
9 and withdrawal of parts from the machine or by automatic
lQ loader means to facilitate this transfer.
- 11 When it is desired to automate parts requiring a
12 variety of machining functions to be performed, including
13 cylindrical grinding of one or more diameters, the parts
14 have been processed efficiently on a high volume basis by
15 I'i employing what is known as a machine "transfer line". The
16 ¦~txansfer line may comprise a plurality of serially disposed,
17 !Idedicated, part-specific machining stations which perform
; 18 ~¦unique functions such as drilling, milling, spline-rolling,
~ 19 ¦¦etc. Often, the builder of a tranfer line of machining
1~ 20 stations is able to select the type of machine needed ~rom
21 the various machine tool manu~acturers and, sometimes a
2Z speciality station is even developed for a given part.
23 For parts having a cylindrical surface to be
24 finished by ~rinding, transfer line users have been inhibited
25- in production functions, by the inherPnt disadvanta~e of
27 state-of-the-art cylindrical grinding machines in that work
I cannot pass ~irectly through the machine along a substantially
28 lihoriæontal path. Users of transfer lines employ varieties
- of conveyor systems to transport the workpieces serially
30 ll fxom station to station, but when it becomcs necessary to
31 Imachine a cylindrical diameter, the workpiece is often
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1 ~!removed from the ma.instream o~ part flow, tranported to a
2 'xemote grinding machine by expensive and complex loading
3 mechanisms such as overhead gantry supported loaders which
4 are well-known in the ark, and, ater machining, the workpiece
'is removed from the grinder and brought to the mainstream of
6 workflow where it is reinserted into the system for subsequent
7 j.machining operations.
8 , Applicant has obviated the difficulties inherent
9 in the prior art gxinders, by providing a cyIindrical grinder
which is capable of part flow by conveyor means along a
11 substantially horizontal path through the machine so that
12 unidirectional flow of parts may occur in the transfer of
13 rough and finished workpieces, thus enabling the grinding
14 I,machine to be utilized in a transfer line system, or as a
,"stand-alone" machine.
16 ¦ It is therefore an object of the present invention
17 ¦to provide a machine having through ~low capabillties.
18 ¦ Another object of the present.invention is to
19 jprovide a machine having a substantially reduced utilization
lof sliding way systems for carrying the main machine el~ments.
21 . ~ Another object of the present invention is to
22 provide a tangential machineJ having a substantially vertical
23 line of centers between the work axis and feed drum axis
24 wherein a wheel cutting surface is passed tangentially
25, ¦across a surface of the workpiece at a preselected workpiece
26 ¦diameter at the line of centers.
27 ¦ . Summary of the Invention
28 ¦ An orbiting cutter tangential machining tool has a ~:~
29 ,base, supporting a pair of driven wor~heads which in turn
jsupport and drive a workpiece about its axis of rotation.
31 ;~ quill is rotatably carried in a rotatable wheel support
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1 ,ldrum and a grinding wheel is rotatably carried in the quill.
2 '~hc quill is eccentric to the drum axis of rotation and the
, grinding wheel is eccentric to the quill axis of rotation.
The head which carries the drum, quill, and grinding
wheel cutter, is affixed to the base so as to carry the
6 drum above one of the wor~heads and orient the drum axis
,7 relative to the work axis. Means are provided to drive the
j8 ;drum in rotatable fashion when performing a grinding function,
' g and means are provided to index the quill to predetermined
positions about the quill axis to vary the position of the
11 grinding wheel axis relative to the drum axis to compensate
12 for changes in wheel size.
13 A dressing wheel is rotatably carried in a housing
14 which is affixed to the base 50 that a wheel cutting surface
- 15 is passed tangentially across the surface of the dressing
'~ ;16 Iwheel ak a line of CQnterS passing through the dressing
17 I wheel, grinding wheel, and support drum axes. In the preferred
lmode, the wheelhead and drum are disposed so as to provide a
~;19 substantially vertical line of centers between the workpiece,
i and drum axes, so that as the wheel cutting surface is
21 "orbited through an arc about the drum axis, the wheel cutting
122 ,'surface engages the rough work stock and is fed along a
23 1i cuxved, "generally chordal" path,'passing tangentially
24 l~across a surface of the workpiece at a preselected workpiece
.25 Ijdiameter at the vertical line of centers.
Bxief Description of the Drawings
!~ Fig. 1 is a perspective view of an orbiting cutter
28 l machining tool.
2g Fig. 2 is a front eievational view of the orbiting
cutter tangential machirling tool of Fig. 1.
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1 ¦I Fig. 3 is a right ~levation o~ ~n orbiting cutter
2 tangenti~l machining tool kaken along the line 3-3 of Fig~
3 ~ 2,
4 Fig, 4 is a ~section through the cutter support of
a machlning tool taken along the line 4-4 of Fig. 1.
.
6 Fig. 5 is a section through the cutter spindle and
7 quill. Fig. 5a i5 a section through the quill indexer.
8 Fig. 6a is an end view of the wheelheaa taken
9 along the line 6a-6a of Fig. 5.
Fig. 6b is a view showing the elements of Fig. 6a
11 after indexing.
12 Fig. 7 is a diagramatic view depicting the relationship
13 of a cut~er, workpiece, and dressing wheel.
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14 Fig. 8 is a diagramatic view depicting the action
;be~ween the cutter and workpiece.
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16 1! Fig. 9 is a front elevation of an alternative
17 Ll embodiment of the orbital tangential machining tool arranged
18 1I for shoulder machining.
19 11 Description of the Preferred Embodiment
~ ll Refer~ing now to the drawings, and particularly to
21 I'Fig. 1 ~hereof, there is sho~n a perspective view of an
22 ¦lorbiting cutter tangenkial machining tool 10, having a base
23 ¦~11, which carries a first workhead 12 and a second workhead
24 ~~13 at opposite ends of the base 11. A wheelhead 14 is
Imounted to the top 15 of the first workhead 12 and carries a
26 Irotatable cutter, herein depicted as a grinding wheel 16, by
i 27 ¦,a rotata~le drum 17 within the wheelhead 14. The grinding
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28 ''wheel axis 18 is eccentric to the drum axis 19 so that as ~
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29 the drum 17 is rotated, the grinding wheel 16 is carried in
an orbital arcuate path 20 about the drum axis 19, passing
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31 the cutting surface 21 of the grinding wheel 16 tangentially
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1 1!across a workpiece 2~ at the hotto~nosk point 23 of the
2 l~orbital path 20. ~ conveyor mechanism lOa i5 shown to
3 provide a rneans for txansferring workpieces into and from
4 'the machin~ 10.
Fig. 2 depicts a front elevational view of the
6 or~iting wheel cutter grinding machining tool 10, illustrating
7 that the first and second workheads 12, 13 are mounted with
8 work suppoxt means 24, 25 dis~osed towards one' another,
9 thereby enabling a workpiece 22 to be supported on the work
support means 24, 25 while the workpiece 22 is rotated about
11 its axis 26 of rotation. The workhead drive motor 27 is
12 shown mounted to a motor mounting plate 28 at the side 29 of
13 ~he base 11 and the motor shaft 30 is coupled to a drive
14 , ~haft 31 which extends through the base 11 to the opposite
,side. The drive shaft 31 is commonly connected to the first
16 1,1 and second workheads 12, 13 by drive trains 32, 33 respectively,
17 !i so that the first and second workhead spindles 34, 35 are
18 1! driven in unison when rotating the workpiece 22. Here it
19 l,should be noted that modification to,the sys~em may be
' utilized wherein the drive shaft 31 is connected to only one
21 ,,of the workheads. Such alternative system may be useful
22 ll when a part is chucked in only one spindle or when it is
23 ¦desired to have merely a footstock as is well-known in
24 Ithe art for supporting an opposite end from a drivin~
¦headstock. The wheelhead 14 is shown mounted to the top
26 !~ surface 15 of the Eirst workhead 1~ and the drum 17 is
7 I;rotatable abou~ the drum axis 19. The grinding wheel 16 is
8 ~ rotatable about -the grinding wheel axis 18 which is eccentric
~,to thc drum axis 19. The grinding wheel spindle 36 extends
from the rear 37 of the wheelhead 14 and is drivingly connected
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1~-rl~hrou~h an articulated drive system 38 to a grinding wheel
2 ,drive motor 39 which is mounted ~o the motor support 28.
3 Grindin~ Wlleel Drive
4 The articulated drive system 38 employed for the
grinding wheel motor 39 is very similar to that used for
6 driving a dentist's drill, where the drive motor must remain
7 :stationary while the driven pulley is transported to various
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8 spatial orientations. In the drive sys~m 38 depicted by
9 Fig. 2, a first pulley 40 is affixed to the motor shaft 41
1~ and connected by belts 42 to a second pulley 43 which is
11 carried at the end 44 o a first link arm 45 wherein the arm
12 45 is.pivotally carried on the motor shaft 41 so that the
13 second pulley. 43 may gyrate around the first pulley position
14 but the center distance between the two pulleys 40, 43 is
: 15 fixed by of the rigid arm 45. A thi.rd pulley 46 is adapted
16 Ito the same axis 47 as the second pulley 43 so that the two
17 ~,rotate together, at the same speed. The third pulley 46 is
18 1I connected by belts 48 to a fourth pulley 49 which is carried
j - 19 lion the wheelhead spindle 36, and the cen-ter distance of the
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.~ 20 ilthird and fourth pull~ys 46, 49 is maintained by a second
21 ~'rigid link arm 50 which is pivotally adapted at opposite
22 1,1, ends to both the wheelhead spindle 36 and the axis 47 of the
¦second pulley 46. In this manner, therefore, the fourth
24 ¦pulley 49 may gyrate around in space drivingly connected to :
25 Ithe motor 39 by the pulley system indicated yet the center ...
26 ¦!distance between respective pairs of pulleys.40, 43 and 46,
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49 is maintained by the rigid link arms 45, S0.
28 l' The view in Fig. 3 is a right elevational view of
29 'the drive system 38, depicting the workhead drive motor 27
.mounted to.the motor support 28, and the wheelhead spindle
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1 ~;drive motor 39 also mount.ed to the motor support 28. A
2 first position of the wheelhead spindle axis 18 (carrying a
3 Imaximum diameter wheel) with respect to the drum axis 19 is
4 indicated by the solid lines and the articulated dxi~e arms
45, S0 are shown connecting the drive motor 39 to the
6 spindle axis 18. The phantom position indicates an alternative
7 position to which the wheelhead spindle axis 18 has been
8 moved by virtue o rotation of the drum 17, (with a fully
9 compensated minimum diameter wheel) and the articulated
drive system 38 is shown accomodating the movement of the
11 wheelhead spindle 36. The feed drum motor 51 is shown in
12 phantom outline mounted to the top surface 51a of the wheelhead
: 13 14 for providing rotational movement to the feed drum 17.
14 Feed Drum
Fig. 4 is an elevational section taken through the
iwheelhead 14 illustratihg that the feed drum 17 is rotatably
17 ¦I carried about its axis 19 in a set of bearLngs 52 which are
18 jlmounted in the bearing bore 53 in the wheelhead 14. The
19 l,bearings 52 are spaced by a spacer ring 54 and the inner
20 ,~races 52a o.f the bearings 52 are carried on the close
21 I~itting diameter 55 of the drum 17. A shoulder 56 is provided
22 lon the frontmost end of the drum 17 and one bearing 52 is
23 ¦jlocated against the shoulder 56, which is adjacent to the
24 ¦,close-fitting diameter 55. The other bearing 52 is carried
l¦at the rear of the drum 17 and is clamped to the drum 17
26 ,11 through the drum pulley 57, which is pulled snuggly against
27 .,the bearing 52; the spacer ring 54; on through the other
28 '~bearing 52 into the shoulder 56, locking the assembly, by
29 .screws 58. The drum pulley 57 has a central bore 59 concentric
with its outer diameter 60, which bears on a close-fitting-
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1 !di~eter ~1 at the rear of the drum 17. The wheelhead 14
2 has a bearing cap 62 fixed by screw~ 63 at ~he frontmost end
3, '64 a~ainst which stationarily held outer race 52b of the
1 4 bearing 52 is clamped. Clamping is provided at the rear of
' the wheelhead 14'hy a bearing retainer 65 which has a thin
6 ring section 66 which slidably bears within the wheelhead
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7 ; bearing bore 53, and a flange portion 67 at the outermost
~ 8 axial position of the thin ring section 66, through which
: 9 screws 68 are provided.to pull the reta,iner 65 towards the
wheelhead 14, locking the assembly. A relief diameter 69 is
11 . bored in the wheelhead 14 to accomodate the flange portion .
: ' 12 . 67 of.the bearing retainer 65. A feed drum motor 51 is
:; 13 mounted to a motor mounting plate 70 at the top 51a of the
:~ , 14 wheelhead 14, and a drive pulley 71 is sec,ured by a key 72
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;,to the motor shaft 73 ~or positive rotation therewith. The
16 I',pulley 71 has grooves 74 around its circumference to ca~ry
, , 17 tibelts 75, and the grooves 74 are in line with similar grooves '
., 18 jj76 which ha~e been machined about the drum pulley 57. The
:, 19 ll~belts 75 impart rotational drive from the feed drum motor
, pulley 71 to the drum pulley 57. A quill 77 is rotatably
! carried within the drum 17 so that the quill axis 78 is
' 22 1 eccentric to the drum axis 19. A grinding wheel 16 is
23 ¦ carried on a grinding wheel spindle 36 which is rotatably
,24 1 carried in the quill 77, and the ~rinding wheel axis 18 is
, , , 25, ¦~eccentric to the quill axis 780 Therefoxe, lt is evident~
'., ~ 26 ¦,that rotation of the quill 77 about its own axis 78 will
27 1! vary the eacentricity of the grinding wheel axis 18 relative ,,
I , 28 ~~to the feed axis 19.
" 29 li Wheel Compensation
~ I ,~. The enlarged section depicted in FigO 5 is takcn '
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1 ,lat the rear of the grinding wheel spindle 36, illustrating
2 ,the relationship of the spindle 36 to the quill axis 78.
3 F~rther d~picted is the compensating mechanism 79 whereby
4 the grinding wheel axis 18 may be selectively moved relative
to the feed drum axis 19 to compensate for changes in wheel
6 diameter and, hence, changes in the orbital path 20 of the
7 cutting surface 21 (shown in Fig. 1) of the ~rinding wheel
8 16 xelative to the feed drum axis 19~ The quill 77, in
9 normal grinding operation, does not rotate relative to the
feed drum 17, but rather it is relatively fixed with the
11 drum 17 by a releasable braking means 80 (not detailed) and
12 is carri~d about the feed drum axis 19. However, as the
13 grinding wheel diameter changes, it is necessary to rotate
14 ; the quill 77 relative to the feed drum 17, and the compensating
mechanism 79 must be employed ~or this purpose.
I6 il The compensating mechanism 79 consists, in part,
17 jlof a cam 81 which is carried on a close-fitting pilot diameter
18 1~82 extending from the rear of the quill 77, through a bore
19 ij83 in the cam 81. A gear 8~ is mounted to the.pilot diameter
l82 by means of a bore 85 through the gear 84 and the gear 84
21 ''and cam~81 are clamped to the quill 77 by a locknut 86 which
22 lis threadably secured to the rear 87 of the quill 77. A
23 ~¦spacer ring 88 is provided on the pilot diameter 82 of the
24 I!quill 77 so that the gear 84 is held in a spaced relationship
25~ 1¦ from the cam 81 as the two are clamped toqether in assembly.
26 1 A key 89 is carried in a keyseat 90 which is machined into
! the surface of the pilot diameter 82 of the quill 77 and a
28 ~ keyway 91, common through the gear 84 cam 81 and spacer
29 ring 88, is provided so that a positive drive is established.
A brac~et 92 is shown out of position, r.lounted to
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1 llthe rear end 93 o~ ~h~ feed drum, and the br~cl;Pt 92 carries
2 a housing 9q thereon. The housing 94 has a central axis 95
3 which is paralle~ to the qui~l axis 78 and a thxough-bore 96
is provided in the ho~sing. A first bearin~ set 97 is
carried at one end 98 o. the housing bore 96 by snap rings
6 99 provided to furni~h shoulders for bearing retention, and
7 a second bearing set 100 is provided at the other end 1~1 of
J ~.
: , 8 the bore, and it t.~o, is retained by snap rings 102~ A
~; , 9 crank pin 103 is rotatab~y carrie~ in the first set Ot
bearings 97, and i.s retained fro~l moving axially relati~e to
11 the bearings 97 by a pair of snap rings 104 located in
- 12 grooves 105 on the bearing diameter 106 of the crank pin
13 103. At the outer end 107 of the crank pin 103 a crank
; 14 lever 108 is carried on a reduced diameter 109 of the crank
pin 103 and is connected thereto by a key 110 so that t~e
16 Icrank lever 108 and the crank pin.103 will move in unison
17 'about the housing axis 95. The crank lever 108 is retained
18 ¦to the crank pin 103 by a snap ring 111 which entraps the
. ¦crank lever 108 axially, between a shoulder 112 on the crank
2~ pin 103 and the snap ring 111. The crank lever 108 extends
21 itransversèly from th~ housing axis 95 and, at its distal end
22 113, a bore 114 is provided through the crank lever 108,
23 parallel to the housing axis 95. A pin 115 extends through
24 the bore 114 and supports a roller 116 which is rotatably
carried on the pin 115. The pin has a head 117 at the one
26 end and a snap ring 118 at the opposite end so that the
27 roller 116 is secured in ixed axial relationship with the
28 ,crank lever 108. The roller 116 is axially disposed directly
29jjabove the cam 81 which is carried on the quill 77.
30 11 A plunger support block 119 is fixed to the rear
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1 ~.end 93 of the feed drum 17 and a bore 120 is provided through
2 - the support block 119, with the bore axis 121 perpendicular
3 to the quill axis 78; that is, parallel to the r~ar end 93
4 of the feed drum 17. ~eferring to Fi~. 6a, a plunger assembly
122 is slidably carried in a support bushing 123 in the
6 support block 119, so that the plungex assembly 122
7 can move axially with resp~ct to the block 119, and the
8 plunger assembly 1~2 is comprised of three elements: a
9 plunger body 124, which is a cylindrical element having an
axial bore 125 extending from its topmost surface 126 down
11 into the body 124 and terminating near the head 127 at the
12 bottom end 128; a plunger pin 129,.which is a cylindrical
13 pin in close-fitting relationship with the bore 125 of the
14 plunger body 124. wherein the bottom 130 of the pin 129 is
flattened and the top end 131 is of spherical form, with a
16 .slot 132 through the pin 129 and ~ pin 133 held in the body
17 jl24, passing through the slot 132; a plunger spring 134
18 Illocated in the plung r body 124, comprising a helical spring
19 ;compressed and preloaded to such position so as to force the
~ plunger pin 129 and the plunger body 124 away from one .
Zl , another.~The bottom end 128 of the plunger body 124 bears on
22 , the cylindrical diameter of the crank roller 116.
23 1 FigO 5 shows that a pinion shaft 135 is carried in
24 ,! the second set of bearings 100 and restrained from axial
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1I movement therewith by a shoulder 136 at the internal end of
26 1l the shaft 135 and pinion 137 at the external end of the
27 "shaft 135 which is carried on a reduced diameter 138 of the
28 shaft 135 which bears in a bore 139 of the pinion l37. A
29 nut 140 is threadably securcd to the shaft 135 to clamp the
shat 135 and pinion 137 to the bearing set 100. A key 141
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1 ! is provided in the shaft 135 which bears in a keyway 142 in
2 ~he pinion 137 50 that positive drive may be had between the
3 shaft 135 and pinion 137. A one-way clutch 143 ~such as a
4 sprag clutch or any similar unidirectional drive clutch) is
containcd between the two bearing sets 100, 97 and adapted
6 ~o connect the pinion shaft 135 to the crank pin 103, so
7 that the crank pin 103 may be reciprocally moved in clockwise
8 and counterclockwise directions about its housing axis 9S,
.
~ 9 but the pinion shaft 135 will only be urged unidirectionally.
:: 10 The crank roller 116 is shown spaced above the cam 81, and
11 the pinion 137 is shown in mesh with the gear 84.
12 . Compensator Operation
. 13 Referring now to Fig. 6a, the rear view of the
: 14 compensator mechanism 79 of Fig. 5, illustrates that the
15 ,support bracket 92 is affixea to the feed drum 17 by screws
16 144, and an extension spring 145 is shown attached at one
17 "end to a spring pin 146 affixed to the feed drum, having its
18 other end attached in a hole 147 in the crank lever 108 so
: 19 ,,that the crank lever 108 is biased in an upward direction by
- the extension spring 145. The plunger support block 119 is
21 , shown affixed to the feed drum by.screws 148, and the plunger
1 22 ~lassembly 122 is shown bearing on the crank roller 116. The
i. 23 1! cam 81 is shown,at such position that a distance "Al" is
24 ¦Imaintained between the roller 116 and the cam 81. The
25, 1I pinion 137 is in consta~t mesh with ~he gear 84, which is
: 26 llaffixed to the quill 77. A trip lever 149 is shown pivotally~ . ij . .
27 mounted to the wheelhead 14 and actuatable by a clevis
28 mounted cylinder 150 and piston lSl set, wherein the piston
29 rod 152 is clevis-mounted to the trip lever 149 and the :
~.cylinder 150 is.clevis-mounted to the wheelhead 14. ~herefore,
7~
1 !iactuation of the piston lSl and c~linder lS0 with respect to
2 'one another will cause the trip lever 149 to pivot about its
3 pivot pin 14a.
4 In normal grinding operations the trip lever 149
is carried in the phantom position 153 shown in Fig. 6a,
fi that is, the "up position". ~hen the feed drum 17 is driven
7 in the counterclockwise direction~ and it becomes necessary
8 to compensate the grinding wheel axis 18 relative to the
9 feed drum axis 19 to accomodate changes in wheel diameter,
the piston 151 and cylinder 150 are actuated so as to pivot
1~ the trip lever 149 to the "down position"; that is, the
12 position shown by the solid line in Fig. 6a. Also, the
13 quill bra]ce 80 (not detailed) is released. Thereafter, the
14 following sequence of operations will occur: as tne plunger
~ 15 .assembly 122 approaches the trip lever ramp 154, the plunger .:
: 16 ¦I pin 129 will strike the ramp lS~ surface and drive the .
. 17 llplunger assembly~122 down, driving the crank roller 116 down
~ ~j 18 jlas well, to the- point where the crank roller 116 contacts
~ 19 ¦¦the cam 81. At this point, any further downward movement of
!Ithe plunger pin 129 which may be required (due to certain
21 jimanufacturillg inaccuracies and overtravel) will be ahsorbed
j 22 ¦¦ by compression of the plunger spring 134 and such further
23 overtravel movement will take.place only between the.plunger
24 pin 129 and plunger body 124. The crank lever 108 moves in
a small clockwise increment, taking the extension spring 145
. 26 to.a still further position, increasing its load. No movement
27 ¦of the pinion 134 or gear ~4 has occurred at this time, due
8 , to the arrangement of the one-way clu~ch 143 of Fig. 5 which
is now permitting relative movement to occur between the
i stationary pinion shaft 135 and the arcuatcly-àdvanced crank
31 pin 103. As the plunger assembly 122 is passed under and
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1 ~iaway from the trip lever 149, the extension spriny 145
2 ~,return~ the crank lever 108 to its "up position", and the
3 crank roller 116, in turn, lifts the plunger assembly 122 to
i 4 its home or upward position. Since the crank lever 108 has
now moved through a counterclockwise direction through an
6 arcuate increment corresponding to vertical movement of the
7 roller "A}", the pinion 137 will now be rotated through a
8 like counterclockwise arcuate increment due to the now-
9 driving action of the one-way clutch 143 of Fig. 5, as the
lQ crank pin 103 and pinion shaft 135 move in unison. The
11 arcuate coun~erclockwise movement of the pinion 137 will now
lZ be translated directly into a reduced clockwise arcuate
13 movement of the gear 84, by virtue of the direct interaction
; 14 of the pinion 137 and gear 84, and the respective ratio of
j 15 the two, and the quill 77 is rotated, carrying the wheel
16 i,spindle axis 18 indexably about the quill axis 78~
17 jl Fig. 6b illustrates the elements of Fig. 6a after
18 1! a series of compensating increments has occurred. The
!i
19 ¦'lviewer can appreciate that the orbit radius, "Ro" de~cribes
'the arcuate the path 20 through which the cutting surface 21
21 I~,of the grinding wheel 16 moves about the axis 19 of the feed
22 Idrum 17, is made up of the sum of the distance from the feed
23 I!drum axis 19 to the ~rinding wheel axis 18, "L", plus the
24 i¦ radius oE ~he wheel, "Rw".
Thus it can be seen that as "Rw" varies due to
26 ¦wheel wear and~or dressing of the wheel 16, the dimension
27 I"L" must be varied to keep "Ro" as a constant ~igure. It is
28 ~ usually desirable to compensate in even increments on grinding
29 machines (however, varied increments could be utilized in
some cases). }lere, for the sake of illustration, and tG
31 understand why a non-circular cam surface 155 has been
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1 ~employed, it is desired to vary dimension "L" in even linear
2 'increments. Since the grindin~ wheel sp.indle axis moYes
3 along an arcuate path about the quill axis 78 it may be
4 readily appreciated that -to maintain even incremental changing
5 of "L", the incremental angular movement of the grinding
6 wheel axis 18 about the quill axis 78 must be uneven. Thus,
7 to vary the angular movements of the quill 77 (through
8 movement of the pinion 137 and the gear 843, it is necessary
9 to vary ~he dimension between the crank roller 116 and the
cam surface 155, which affords a positive stop for the crank
11 roller 116 in its downward stroke. ~herefore, dimensian
12 "A2", and so on, will be different than dimension "Al" of
13 Fig. 6a to accomplish uneven angular increments of the
14 quill 77 about its axis 78.
. Grindina Geometry
I .,
16 I Fig. 7 diagramatically depicts the relationship of
17 ¦the grinding wheel 16, workpiece 22, and dressing wheel 156
18 l.relative to the feed drum axis 19. Here, as previously
19 ~Idescribed in Fig. 6b, the grinding wheel cutting surface 21
is carried in an orbital grind swing "Ro", as a constant
21 llfigure between the feed drum axis 19 and the preselected
, Z2 ¦jgrind surface 22a of the workpiece 22. The dre~slng wheel
, . 23 11 156 is rotatably carried on its wheel axis 157 and held in a
24 fixed relationship relative to the hase 11 so that the
25~ jorbital grind swing "Ro" will carry the cutting surface 21
! 26 i of the wheel.16 past the cutting suracé 156a o the dressing
27 wheel 156 so that it is not necessary to advance the dressing
28 ' wheel 156 towards the grinding wheel 16 when dressing is ~:~
29 j required. A maximum size grinding wheel 16 is depicted by
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, 30 , the solid line, and a fully-compensated, minimum grinding-
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1 ,.wheel 16a is shown, in phantom, in contact with the workpiece
2 ,22 at thc orbital grind swing, "Ro".
3 Turning now to Fig. 8, the interaction of the
, ~ grinding wheel 16 and the wor~piece 22 is shown. The grinding
: 5 wheel cutting surface 21 is moving along an arcuate path
6 which is the locus described b~ ~he orbital grind swing
7 ~"Ro" about the feed drum, axis 19 and the workpiece 22 is
8 rotated about its own axis 26. The rough, workpiece surface
22b is shown in phantom, and the grinding wheel 16 is shown
10 in phantom at first contact with the pre-ground workpiece
11 surface 22b~ The grinding wheel 16 continues to reduce the
12 workpiece 22 in diameter as it moves along path ~0, at its
~ 13 radius "Ro" until finally, at the bottommost point of its
v 14 ;orbital grind swing 158, the grinding wheel 16 is passing
15 .tangentially across the surface 22a of the preselected
. 16 ~'f~nished workpiece 22 (shown solid) at a point coincident
! 17 ll with the vertical line of centers 159 between the workpiece
: ~ 18 ! aXis 26 and the ~eed drum axis 19. Thus, it may be readily
.,
19 ~liappreciated that as the grinding wheel is orbited about the
20 ~feed drum axis 19 at a constant angular speed, omega, the
21 I radius of the workpiece 22 will be reduced by a lesser and
j 22 I,lesser amount until, at last, the grinding wheel 16 is
23 l~earing the bottommost point of its arc 158, stock removal
,. .
.~ 24 will be in the nature of millionths of an inch, and finally
25, ¦¦ zero at the point o tangency of the workpiece surface 22a
3 26 l,and the orbital grind swing "Ro".
27 !1 Alternate Embodiment .
28 I Fig. 9 depicts an alternative embodiment of the
~ 29 present invention, illustrating that placement of a wedge-
3 30 shaped sectiGn 160 ~etween the workhead 12 and the wheelhead
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1 . 14 can pivot the wheelhead feed drum axis 19 to a predetermined
2 ~angle with respect to the workpiece axis 26, to simulate the
3 function of a state of-the-ar-t "angular wheelslide" grinding
4 machine. Such machin~ is useful when it is desired to grina
a shoulder on a workpiece which may or may not be adjacent
: 6 to a grind diameter~ The orbital action of the wheel may be
7 .utilized to approach and feed into the workpiece from an
8 angular vector other than normal to workpiece axis. Any
9 suitable drive means may be utilized to provide a wheelhead
spindle drive, and a simple reorientation of the axis of
lL rotation 157 of the dressing wheel 156 relative to the base
12 11 may be done to provide a truing means for dressing adjacent
~ 13 surfaces on the srinding whèel 16 which are angled relative
:: 14 to the grinding wheel spindle axis 18.
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