Note: Descriptions are shown in the official language in which they were submitted.
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Background of the Invention
This invention is related to linkage mechanisms for moving a
controlled member along a substantially linear path of motion, and more parti-
cularly to a linkage adapted to move a controlled member in a linear motion as
one of the links is being rotated.
Some industrial applications require a workpiece or other elongated
member to be moved along a linear path in a reciprocal motion. ~or example, a
stamping blank must be delivered to a die, and then removed from the die.
Conventionally, the work transfer means employ a variety of mechanisms, such as
a rack and pinion to achieve the linear motion.
Summary of the Invention
The broad purpose of the present invention is to provide a linkage
mechanism having a pair of links pivotally connected to a controlled member for
moving it along a l~near path of motion as one of the links is pivoted by an
appropriate po~er means.
Qne embodiment of the present invention provides a straight line
link mechanism, comprising: a support; a first link; first pivot means con-
necting the first link to the support for pivotal motion; a second link;
second pivot means connecting the second link-to the support for pivotal motion,
the second pivot means being disposed a first distance~from the first pivot
means; a third link; third pivot means connecting-the third link to the first
link for relative pivotal motion a distance from the first pivot means of about
one half said first distance; fourth pivot means connecting the third link
for relative pivotal motion to the second link a distance from said second pivot
means of about 1.25 times said first distance; said fourth pivot means being
connected to the third link a distance from the third pivot means of about 1.25
times said first distance; a controlled member, and means pivotally connecting
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the controlled member to ~he third link a distance of about 1.25 times said
first distance from the fourth pivot means; a fourth link; fifth pivot means
connecting the fourth link to the support for pivotal motion, the fifth pivot
means being disposed said first distance rom the second pivot means; a fifth
link; sixth pivot means connecting the fifth link to the support for relative
pivotal motion, the sixth pivot means being disposed said.first distance rom
the ~ifth pivot means; a sixth link; seventh pivot means connecting the sixth
link to the fourth link a distance from the fifth pivot.means of about one
half said first distance; eighth pivot means connecting the sixth link for
relative pivotal motion to the fifth link a distance o about 1.25 times said
first distance ~rom said sixth.pivot means,~said eighth pivot means being
connected to the sixth link a distance o about 1.25 times said first distance
~rom the seyenth pivot means such that the sixth link is movable in parallel
: motion with the third link; means pivotally connecting the sixth link to the
~, ~or~t~ro ll e~l
member a distance of about 1.25 tlmes said:first:distance from the
eighth piv~t means; and power means connected to one of said links such that as
the first link is ~ved:in a pivotal moticn:with respect to the support, the
controlled member is-mQved alon~ a substantiall~ linear path of motion.
: ~ reversing the motion~of the drlve link, the controlled member is
20. moved in the opposite direction. The mechanism can be adapted 50 that by
rotating one of the links in a 360P path of motion the controlled member ls
firs~t moved in a linear path and then moved in the opposite direction in a
curved path
Another embodi~ent of the present invention provides a straight-
line linka.ge mechanism, comprising~ a support; a first link; first pivot means
connecting the ~irst link to the support or pivotal motion; a second link;
second pivot means.~connecting the second link to the support for pivotal motion,
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the second pivot me~ns being disposed a first distance from the pivot means;
a third link; third pivot means connecting the third link to the first link
for relative pivotal motion a distance from the -~irst pivot means of about one
hal said first distance; fourth pivot means connecting the third link for
rela*ive pivotal motion to the second link a distance from said second pivot
means of about 1.25 times said first distance; said fourth pivot means being
connected to the third link a distance from the third pivot means of about
1.25 times said first distance; a controlled member, and means pivotally con-
necting the controlled member to the third link a distance of about 1.25 times
said first distance from the fourth pivot means; a fourth link; fifth pivot
means connecting the fourth link to the support for pivotal motion, the fifth
pivot means being disposed said di.stance from the second pivot means; a fifth
link; a sixth link hav mg one end pivotally-connected to the support, said
first distance from the first link; and a sixth link; cam means connected
to the first link and the sixth link such that as the sixth link is being
rotated, the controlled member is moved horizontall~ along a generall~ linear
path, and then lowered vertically a predetermined distance.
A further embodiment o~-the present:invention provides a liting
mechanism, comprising; a base; a first link; first pivo~ means connecting
the first lInk to the base ~or pivotal motion; a second link; second pivot
means connecting the second link to the base for pivotal moti.on, the second
pivot means ~eing disposed a first distance from the first pivot means; a third
link; third pivot means connecting the third link to the f:irst link`for re-
lative pivotal m~tion, the third pivot means being located a distance from the
$irst pivot means of about one half of said first distance; Eourth pivot means
connecting the third link for relative pivotal motion to:the second link, the
fourth pivot means being located a distance from the second pivot means of
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about 1.25 times said first distance; said fourth pivot means being connected
to the third link, and being located a distance from the third pivot means of
about 1.25 times said irst distance; a lifted member having a weight on a
first side of said base, and means pivotally connecting the lifted member to
the third link, a distance of about 1.25 times said first distance from the
fourth pivot means; a fourth link; fifth pivot means connecting the fourth
link to the support for pivotal motion, the fifth pivot means being disposed
said first distance from the second pivot means; a fifth link; sixth pivot
means connecting the fifth link to the support for relative pivotal motion, the
sixth pivot means being disposed said first distance from said fifth pivot means;
a six~h link; seventh pivot means connecting the sixth link to the fourth
link a distance from the fifth pivot means of about one half of said first
distance, such that the sixth link is movable inparallel relationship with the
third link; eighth pivot means connecting the sixth link for relative pivotal
motion to the fith link, the eighth pivot means~being located a distance of
about 1.25 times said first distance from said sixth pivot means, said eighth
plVOt means being connected to the sixth link, and being located a distance
of about 1.25 times said first distance from the seventh-pivot means, such that
the eighth link is movable in parallel motion wlth the third link; means
pivotally connecting the sixth link to the lifted member a distance of about
1 25 times said first distance from the eighth pivot means; and counter weight
means connected to certain of said links on the opposite side of the base as
the lifted member to at least partially counter balance the lifted member as
it is moved in a vertical motion.
The preferred linkage mechanism can be employed in a variety of
useful applications. ~or example, an overhead system can be suspended for
moving the controlled member along a linear horizontal path beneath the support.
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In another embodiment, the controlled member is connected to a cam to provide
a lifting motion at each end of the horizontal motion. In still anothe-r form
of the invention, the controlled member is balanced by a counter weight and
supporting for a lifting motlon.
In each form of the invention, the mechanical components provide a
lightweight system having a lesser inertia and less friction than other forms
of mechanical mechanlsms.
Still further objects and advantages of the invention will become
readily apparent to those skilled in the art to which the invention pertains
upon reference to the following detailed description.
Description of the Drawings
The description reers to the accompanying drawings ln which like
reference characters refer to like parts throughout-the several views, and in
which:
Pigure 1 is an elevational view showing the prsferred embodiment in
one position;
Pigure 2 is a view similar to Flgure l, but with the controlled
member advanced along its path of linear motion;
Pigure 3 is a view seen along lines 3-3 o~ Figure l;
~20 Plgure 4 illustrates another embodiment of the invention mounted on
an overhead structure;
Pigure 5 is a view similar to Figure 4 but with the controlled mem-
ber disposed at the opposite end of its horizontal transfer path;
~igure 6 is an enlarged view as seen along lines 6-6 of Figure 4;
Pigure 7 is an enlarged view taken along lines 7-7 of Figure 4;
Pigure 8 is an enlarged vlew taken along llnes 8-8 of Figure 4;
Figur0 9 is another embodiment of the invention incorporated in a
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counter-balance lifting device;
Figure 10 is a view similar to Pigure 9, but in which the lifting
device is in the raised position; and
~igure 11 is a view as seen along lines ll-ll-of ~igure 9.
/ = Pre~erred Embodiments
Referrin~ to the drawings, a pre~erred linkage mechanism generally
illustrated at 10 is attached to ceiling 12 by ~eans of a support 14. Mechanism
10 includes a near side linkage means llA and a far-side linkage means llB.
Pour links 16, 18, 20, and 22 each have an upper end connected by
pivot means 24, 26, 28, and 30, respectively, to support 14. The distance
between pivot-means 24 and 26 is a predetermined distance "A". The distance
between pivot means 26 and 28 and between pivot means 28 and 30 is also "A".
Llnks 16 and 2Q are equal in length as are links 18 and 22. Links 32 and 34
are connected to the lower ends of links 16, 189 20, and 22.
Pivot means 36 connect link 32 to link 16 such that the distance
betw0en pivot means 24 and 36 is equal~to one half "A". Plvot means 38 connect
link 34 to link 20 such that the distance between pivot means 28 and 38 is one
half "A". Pivot means 40 connect link 32 to l mk 18 such that the dlstance
bet~een ~ivot means 26 and 40 is equal to 1.25 A. The distance between pivot
20 ~ means 36 and 40 is also equal to 1.25 A. PiVot means 42 connect link 34 to
link 22 such that the distance between pivot means 30 and 42 is equal to 1.25 A,
and the distance between pivot means 38 and 42 is also equal to 1.25 A.
Controlled means 44 ls connected ta the lower end o~ links 32 and
34. Pivot means 46 connect controlled means 44 to link 32 a distance equal to
- 1,25 A ~rom pivot means 40. Similarly, pivot means 48 connect control~led means
44 to link 34 a distance ~rom pivo* means 42 equal to 1.25 A.
Controlled means 44 includes an arm 52 connected to links 32 and 34,
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and lower Support member 54 which has one side connected to arm 52 and its
opposite slde connected to a companion arm on linkage means llB. ~ member 56
carries a pick-up device 58 that is to be moved along a linear path.
An arm 60 is also connected by pivot means 36 and 38 to links 16
and 20.
ReEerring to Pigure 3, linkage means llB~ similar to linkage means
llA9 is mounted on the opposite side of support 14 as mechanism 10, and has a
companion link mounted abreast of each of the links of means llA. The lower end
of lin~age means llB is connected to controlled means 44 to stabilize pick-up
device 58.
The arrangement is such that as link 16 is rotated in the counter-
clockwise direction through a 180~ arc t'B", as illustrated in Flgure 1, the
controlled means ~oves along a linear path illustrated in phantom at "C", from
~ight to left. If link 16 is reversed along its path of motion, controlled
means 44 then moves along the same linear path "C", hu* in the opposite
direction. If~link 16 continues to move along another 180 path illustrated
at "D", the controlled means 44 moves in the opposite direction along a curved
path "E".
Any part of this controlled motion can be applied in a useful
application. ~or illustra~ive purposes, a pa:Lr of actuators 64 and 66 are
connected between support 14 and the two linkage means to alternately push and
then pull the mechanism in a pivotal motion and accordingly move the pick-up
device in a linear path toward the left and then in the opposite direction along
the same linear path, toward the right.
Pigures 4 to 8 illustrate another embodiment o~ the invention in
mechanism 100. This form of the invention is mounted on overhead structure 102
and comprises a three-sided frame formed of arms 104, 106, and 108. Linkage
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mechanîsm 100 has a pair of links 110 and 112 each having their
upper ends connected by pivot means 1l4 and 116, respectively, to
horizontal arm 108. Pivot means 114 and 116 are separated a dis-
tance "F" as illustrated in Figure 5.
A link 118 is pivotally connected by pivot means 120 and
122 to the lower ends o:f links 110 and 112 in such a manner that
links 110 and 112 are movable in a parallel relationship. Th.e dis-
tance between pivot means 114 and 116 equals the distance between
pivot means 120 and 122, while the distance bet~een pivot means 114
10 and 120 and the distance between pivot means 116 and 122 is "F".
Another link 124 has its upper end connected by pivot
means 120 to b.oth links 110 and 118. The lower end of link 124 is
connected by pivot means 126 ~o a horizontal arm 128.
A link 130 has its midsection connected ~y pivot means 122
to both links 112 and 118, and its lower end connected by pivot
means 132 to arm 128. The distance between pivot means 126 and 132
is equal to the distance between pivot means 120 and 122 while the
distance between pivot means 120 and 126 is equal to the distance
between pivot means 122 and 132.
A pick-up device 134 i5 carried on the outer end of arm
128.
. Clevis means 136 and 138 connect arm 128 ta pivot means
126 and 132 as best illustrated in Figures ~ and 8.
Figure 7 illustrates the manner in which. a typical link
112 is connected by pivot means 116 to arm 108. Pivot means 116
includes a short sha~t 140 connected by bearing means 142 with
retainer means 146 retaining the assembl~ in position.
Referring to Figure 6, a cam plate 150 is mounted on arm
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108. Cam plate 150 has a C-shaped groove cam 152 which extends in
an arc of about 180. The upper end of groove 152 ~erminates in a
short groove 154 whi.ch slants downward and toward the left. The
bottom half of cam groove 152 terminates in a short groove 156 that
extends upwardly toward the left.
A cam roller 157 is carried on the upper end of link 130
and rides in grooves 152, 154~ and 156.
Motor means 158 has a shaft 160 carrying a drive link 162
for rotation. The upper end of link 162 has a longitudinal slot
164 which carries roller means 166 which is received in slot 164.
Roller means 166 is carried on the opposite end of pin 167 that
carries cam roller 157. Slot 164 is chosen such th.at when cam
roller 157 is in slot 152~ roller 166 engages the bottom of slot
164, as illustrated in Figure 6. As link 162 is rotated, it pushes
roller 157 in either the counter-clockwise or clock~ise direction
in cam groove 152 depending upon the direction of rotati.on. The
roller is th.en received into ei.ther slot 154 or slot 156. When the
rotation of the motor is reversed, the roller moves to~ard groove
152 to th.ereby move roller 166 in the opposite direction in slot
164. The arrangement is such.that the distance rom sh.aft 16Q to
the position in ~hich cam 166 i.s in th.e bottom of cam slot 164 is
about one half "F".
The arrangement is such th.at as drive link 162 is rotated,
controlled arr~ 128 moves in a horizontal transfer path.between an
extreme position illustrated in Figure 4 and an opposite extreme
position i.llustrated in Figure 5. At the end of the horizontal
trans~er motion, as link 162 rotates to the positîon s.ho~n in chain-
dotted lines in Fi.gure 5 and cam 157 moves into groove 156J the
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pick-up device 134 is lowered a predetermined vertical distance.
When the drive link rotation is reversed, the pick-up device 13~
is then raised to its former horizontal position. Arm 128 is then
hori~ontally moved to the opposite extreme position, illustrated
in Figure 4, until th.e cam roller is at the top of groove 152. As
the link continues its rotation to the position shown in chain-
dotted lines, the pick-up device is then lowered to a position
illustrated at "G" in Figure 1, thus the pick-up device i5 moved
in motion ranges between posi~ion "G" and position "~" as illustra-
ted in Figure 5.
Another embodiment of the invent;on i~ illustrated in
Figures 9 to 11 in the form of lifting means 200. Lifting means
200 comprises a base 202 having an uprigh.t supporting frame 204.
A pair of linkage means 206 and 206' are mounted on
opposite sides of frame 204 for raising and lo~ering a lifted mem-
ber 210. Linkage means 206 and 206' are identical to one another
: e~cept for a righ.t and lef~ hand relationship so that a discussion
of linkage means 206 also applies to the corresponding members of
linkage means 2a61.
Referring to Figures ~ and 10, link.age means 206 includes
links 2Q8, 210, 112, and 214 pivotally connected to frame 204 by
pivot means 216, 218, 220, and 222, respectively. The distance
between pivot means 216 and 218 is referred to as distance "M".
The distance between pi.vot means 218 and 220 and ketween pivot
means 220 and 222 also equals. "M".
A link 224 is connected by pivot means 226 and 228 to
links 2Q8 and 210, respectively. The distance between pivot means
218 and 228 is about 1.25 times "M". Th.e distance ~et~een pivot
means. 216 and 226 is about one half "M".
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A link 230 has one end connected by pivot means 232 to
link 112 and its midsection connected by pivot means 234 to the
outer end of link 214 in khe same manner that link 224 is connected
to links 208 and 210.
A spring member 236 has its ends connected to pivot means
226 and 232, respectively. Return spring 236 functions to prevent
a condition in the linkage system when there is a minimal amount of
torque tending to return the links in the system.
A vertical arm 240 is connected to the outer end of links
224 and
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230 by pivot means 242 and 244, respectively~ in such a ~anner that vertical
arm 240 is vertically movable. The upper end of arm 240 is connected to lifted
member 210, as illustrated in ~igure 11. Similarly, linkage means 20~ is mount-
ed on the opposite end o frame 204 and connected to the opposite side of
lifted member 210. A reciprocating actuator 2~0 is mounted on base 202 and has
a reciprocating piston arm 252 connected to lifted member 210 for raising and
lowering it between its lower position illustrated in ~igure 10 and its upper
position illustrated in Figure 9. A counter-balance weight 260 is carried on
an arm 262 having its upper end pivotally connected to arm 264 of link 214, and
its lower end pivotally connected to arm 266 of link 210. The arrangement is
such that a ].ifted member 210 is raised, counter weight 260 balances a portion
of the weight of member 210 so that it takes a minimal amount of energy for
actuator 250 to raise and lower lifted member 210. The particular relationship
between the links of the respective links permit the lifted member 210 to move
in a substantiall~ linear vertical posltlon as the links are being pivoted, and
provides a relatively light-weight means for connecting counter-weight 216 to
the lifted member.
