U.S. patent application number 09/896956 was filed with the patent office on 2001-11-08 for knotter reset arm relief mechanism.
Invention is credited to Esau, Edward W., Kendrick, Patrick.
Application Number | 20010037733 09/896956 |
Document ID | / |
Family ID | 24066168 |
Filed Date | 2001-11-08 |
United States Patent
Application |
20010037733 |
Kind Code |
A1 |
Kendrick, Patrick ; et
al. |
November 8, 2001 |
Knotter reset arm relief mechanism
Abstract
The dog clutch for a square baler is normally retained in a
disengaged position as a continuously driven sprocket rotates
around it during baling operations. When a retainer for the dog is
released, the dog is released by the retainer and flips out to an
engaged position so as to be driven through one knotter revolution
by a driving lug on the rotating sprocket, whereupon it is reset by
the retainer into its disengaged position. An external lobe on the
rotating sprocket blocks releasing movement of the retainer if the
driving lug of the sprocket is in the immediate vicinity of the
dog, which could otherwise cause an insecure engagement of the lug
with the dog. The dog-engaging seat on the retainer is
spring-loaded to provide yieldable relief in the event binding
starts to occur between the retainer and the dog.
Inventors: |
Kendrick, Patrick; (Hesston,
KS) ; Esau, Edward W.; (Hesston, KS) |
Correspondence
Address: |
HOVEY WILLIAMS TIMMONS & COLLINS
2405 GRAND BLVD., SUITE 400
KANSAS CITY
MO
64108
|
Family ID: |
24066168 |
Appl. No.: |
09/896956 |
Filed: |
June 29, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09896956 |
Jun 29, 2001 |
|
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09518952 |
Mar 6, 2000 |
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Current U.S.
Class: |
100/32 |
Current CPC
Class: |
A01F 15/0858 20130101;
A01F 2015/0866 20130101 |
Class at
Publication: |
100/32 |
International
Class: |
B65B 013/22 |
Claims
1. An improved retainer for use in a control that governs
engagement and disengagement of the dog clutch for a knotter
comprising: a generally T-shaped support having three arms
projecting generally radially outwardly from a transverse axis of
rocking movement of the support, a first and a second of said arms
projecting in generally opposite directions from said axis, and a
third of said arms projecting generally transverse to said first
and second arms, said second arm being adapted to be operated by an
external actuator for causing the support to pivot about said axis
in a first direction during release of the retainer, said third arm
being adapted to be operated by an external reset structure for
causing the support to pivot about said axis in a second direction
during resetting of the retainer; a seat on said first arm disposed
in a blocking position for engageably underlying the shiftable dog
of the clutch and maintaining the clutch disengaged when the
retainer is in an unreleased condition; and relief mechanism
mounting said seat on said first arm in a manner to allow the seat
to shift yieldably away from said blocking position.
2. An improved retainer as claimed in claim 1, said seat being
mounted for pivoting movement on said first arm such that said
shifting of the seat is carried out in a pivoting motion.
3. An improved retainer as claimed in claim 1, said relief
mechanism including a spring.
4. An improved retainer as claimed in claim 1, said seat having an
outermost edge and being undercut beneath said edge to present a
receding lower surface.
5. An improved retainer as claimed in claim 1, said relief
mechanism including a member having a pair of opposite ends, said
member being pivotally attached to said first arm of the support at
a point between said opposite ends, said seat being at one end of
the member, said relief mechanism further including a relief spring
connected between said one arm of the support and the other end of
the member.
6. An improved retainer as claimed in claim 5, said support
including a stop disposed to limit pivoting of the member in a
direction shifting the seat toward the blocking position.
7. An improved retainer as claimed in claim 6, said support further
including a stop disposed to limit pivoting of the member in a
direction shifting the seat away from the blocking position.
8. An improved retainer as claimed in claim 1, said seat being
non-rotating and having a flat, dog-engaging upper surface.
Description
RELATED APPLICATION
[0001] This application is a division of prior co-pending
application Ser. No. 09/518,952, filed Mar. 6, 2000.
TECHNICAL FIELD
[0002] This invention relates to hay balers and, more particularly,
to improvements associated with the clutch that activates the
knotter and twine needles in such a baler.
BACKGROUND
[0003] U.S. Pat. No. 5,782,175 titled "Knotter Clutch Control for
Square Balers" and assigned to the assignee of the present
invention is directed to improvements that prevent the driven dog
of the dog clutch on a baler from releasing to its actuated
position for engagement with the driving lug of the clutch unless
the lug is in a position where positive driving engagement between
the lug and the dog is assured. The dog is normally maintained in
its retracted position as the constantly moving sprocket having the
driving lug mounted thereon rotates around the dog without making
contact. The dog is held in the retracted position by a retainer
that is released in response to the bale reaching a predetermined
size, such release of the retainer permitting the dog to move out
into its actuated position where it is picked up by the driving lug
on the next cycle of revolution of the sprocket. A strategically
located external lobe on the sprocket interacts with the retainer
to prevent its release in the event the baler attempts to release
the retainer when the lug is in the immediate vicinity of the dog,
which release might cause the lug to only partially and temporarily
catch the dog for driving the knotter through an operating cycle.
By preventing the retainer from releasing unless the driving lug is
spaced in its cycle from the dog, either on the approaching side or
departing side thereof, positive interengagement between the lug
and the dog can be achieved.
[0004] The external lobe also has the effect of resetting or
tending to reset the retainer if the retainer has been released
before the lobe reaches the reset roller. While this is of no
particular consequence so long as the dog has been fully tripped
and the operating lever associated therewith has moved past the
retaining roller on the retainer, in some situations the roller may
hang up on the tip of the lever as the external cam lobe tries to
move the retainer in a resetting direction. Damage or breakage of
components may result as the lobe attempts to swing the retainer
inwardly at the same time the dog lever blocks such motion.
SUMMARY OF THE INVENTION
[0005] Accordingly, an important object of the present invention is
to eliminate the potential for the retainer and dog to become
jammed in a knotter clutch control of the type disclosed in the
'175 patent. Such jamming problem is avoided in the present
invention by providing a degree of spring relief between the dog
and the retainer such that, in the event jamming starts to occur,
the spring relief permits relative movement between the two
components in such a direction that one or the other of the
components can continue its movement in the appropriate
direction.
[0006] In a preferred embodiment, such relief is provided by having
the dog-engaging part of the retainer spring-loaded so that it can
yield when untoward binding forces attempt to arise between the
retainer and the dog. Preferably, the dog-engaging part of the
retainer takes the form of a swingable member having a relatively
flat seat for the outer end of the dog lever, such member being
yieldably biased by a tension spring into a dog-blocking position
on the supporting body of the retainer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a fragmentary side elevational view of a square
baler incorporating an improved knotter clutch control constructed
in accordance with the principles of the present invention;
[0008] FIG. 2 is an enlarged, fragmentary side elevational view of
the prior art knotter clutch control as disclosed in patent
5,782,175, such view illustrating the binding problem that can
sometimes arise;
[0009] FIG. 3 is a further enlarged, fragmentary side elevational
view of the improved knotter clutch control of the present
invention illustrating the condition of components during normal
operation when the clutch is in a disengaged condition and the
retainer is holding the dog in its unactuated position;
[0010] FIG. 4 is a side elevational view similar to FIG. 3 but
illustrating how the retainer of the present invention has the
capability of relieving potential jamming forces between the
retainer and the clutch dog;
[0011] FIG. 5 is an enlarged, exploded isometric view of a retainer
constructed in accordance with the principles of the present
invention; and
[0012] FIG. 6 is an isometric assembly view of the retainer.
DETAILED DESCRIPTION
[0013] The present invention comprises an improvement upon the
invention disclosed and claimed in the above mentioned U.S. Pat.
No. 5,782,175. Accordingly, for the sake of brevity, certain
details disclosed with particularity in the '175 patent will not be
repeated herein. Instead, U.S. Pat. No. 5,782,175 is hereby
incorporated by reference into the present specification to the
extent necessary for a full and complete understanding of the
present invention.
[0014] The present invention is illustrated in connection with a
large square baler 210 in FIG. 1. Such balers are typically capable
of producing bales on the order of 1,500 to 2,000 pounds or more.
However, it will be appreciated that the principles of this
invention may also be applied to smaller balers, and such balers
need not be of the "extrusion" type as illustrated in FIG. 1 in
which new bales are progressively forced out the rear end of the
baler through a restricted orifice.
[0015] The baler 210 has a series or "stack" of knotters 212 at the
top of the baler which cooperate with twine needles 214 from
time-to-time to place strands of twine around a finished bale. The
knotters form a secure knot in the opposite ends of each twine
strand and then cut the twine from the tied bale while retaining
the free end of the twine for use in wrapping around the next bale.
Generally speaking, a bale length sensor 216 including a star wheel
218 determines when a bale has reached full length, engages a
clutch 220 associated with the stack of knotters 212, and causes
the knotters 212 to actuate for one single revolution of a drive
shaft 222. After each single revolution of the drive shaft 222, the
clutch 220 is disengaged until the next bale reaches the proper
length. During each knotter cycle, the needles 214 swing across the
bale chamber located inside the baler 210 to present the ends of
twine strands to the knotters 212.
[0016] The knotters 212 are supplied operating power through drive
means such as a chain drive assembly 224. A component of the drive
means, such as a sprocket 232, is constantly driven, so long as
power is being supplied to the baler 210. A chain 230 of the drive
assembly 224 is entrained around a sprocket 232 so as to drive the
sprocket 232 around the axis of the knotter shaft 222. Although the
sprocket 232 is continuously driven, the knotter shaft 222 does not
rotate unless the clutch 220 is engaged.
[0017] The clutch 220 includes a dog 238 mounted on the knotter
shaft 222, and a driving lug 240 mounted on the sprocket 232. The
lug 240 is part of a circular cam ring 242 projecting outwardly
from and integral with the outer face of the sprocket 232. The ring
242 is concentrically disposed about the axis of rotation of the
knotter shaft 222 and has a radially inner, annular surface 242a
that is totally concentric with the knotter shaft 222 except for
the driving lug 240, where the surface 242a projects radially
inwardly and is truncated to present the lug 240.
[0018] The clutch 220 further includes a crank arm 244 that is
fixed intermediate its opposite ends to the knotter shaft 222 and
extends entirely across the face of the sprocket 232. The crank arm
244 has its lower end operably connected with a linkage 246 that
actuates the needles 214, while the opposite, upper end of the
crank arm 244 carries the dog 238. Dog 238 is pivoted to the crank
arm 244 by a pivot 248 and is swingable between a fully retracted
position as illustrated in FIG. 3 which renders the clutch 220
disengaged and a fully extended position (not shown except with
respect to the prior art in FIG. 2) corresponding to an engaged
condition of the clutch 220.
[0019] A coil spring 250 forms an additional part of the clutch 220
and is connected between the crank arm 244 and a tab 252 on the dog
238 to yieldably bias dog 238 toward its engaged position. In such
engaged position, a roller 254 at the outer end of the dog 238
rides along the inner annular surface 242a of cam ring 242. When
dog 238 is in its engaged position, it is located within the
circular path of travel of the moving lug 240, but when dog 238 is
retracted, it clears dog 240 as dog 240 travels around the axis of
knotter shaft 222.
[0020] Clutch 220 is engaged and disengaged by a control broadly
denoted by the numeral 256. Bale length sensor 216 forms a part of
such control and includes, in addition to the star wheel 218, an
inverted, generally L-shaped arm 258 and linkage 270 extending
forwardly from the arm 258. Further details of the construction and
nature of operation of the length sensor 216 can be understood by
reference to the '175 patent. In addition to bale length sensor
216, control 256 includes a lever 272 fixed to dog 238 and
projecting radially outwardly from pivot 248. Lever 272 has a
downwardly facing notch 274 in its outer end.
[0021] The control 256 further includes a releasable retainer 276
for releasably holding the dog 238 in its disengaged position of
FIG. 3. Retainer 276 includes a generally T-shaped, generally flat
support 278 having three legs 280, 282 and 284 that all project
generally radially outwardly from a central hub 286 encircling a
transverse pivot pin 288 on the baler. Legs 280 and 282 extend in
opposite directions from one another, while leg 284 extends in a
transverse direction relative to the legs 280,282. The lowermost
end of leg 282 is pivotally connected to the linkage 270, while leg
284 carries at its outermost end a roller 290 that may be
characterized as a "reset roller" for the retainer 256. Reset
roller 290 is adapted to be engaged along its inner periphery by a
reset flange 292 on the upper end of crank arm 244 during each
knotting cycle.
[0022] The arm 280 pivotally supports a somewhat J-shaped member
294 on a transverse pivot 296 between opposite upper and lower ends
of member 294. As shown in particular detail in FIGS. 5 and 6,
member 294 includes a seat 298 adjacent its upper end that is
adapted to underlie and releasably engage the lever 272 of dog 238
when retainer 276 is in its retaining position of FIG. 3. Seat 298
engages lever 272 at notch 274 at this time. Preferably seat 298 is
shaped to provide an uppermost flat face 298a and an outermost edge
298b. Furthermore, seat 298 is undercut below edge 298b so as to
present a receding, inclined surface 298c. A tang 300 at the rear
of seat 298 projects above the flat surface 298a to define the
upper extremity of the member 294, while a tail 302 projects
laterally from the bottom end of the member 294 generally away from
the clutch 220.
[0023] The support 278 has a lower stop 304 disposed for abutting
engagement with the tail 302 of member 294 so as to limit clockwise
pivoting movement of member 294 about pivot 296. Stop 304 is so
located that when tail 302 is in engagement therewith, seat 298 is
in a blocking position with respect to lever 272 of dog 238 when
retainer 276 is in its retaining position of FIG. 3. Member 294 is
yieldably biased into abutting engagement with stop 304 by a coiled
tension spring 306 connected between the tail 302 of member 294 and
a generally L-shaped tab 308 projecting rearwardly from the upper
end of the arm 280 of support 278. Tab 308 also serves as a stop
disposed for engagement with the tang 300 after a certain amount of
counterclockwise rotation of member 294 from the FIG. 3 position
such as, for example, approximately thirty degrees. In its capacity
as a stop, tab 308 comes into play in the event that spring 306
breaks, in which event it is desirable to keep the lower end of
member 294 from rotating counterclockwise to such an extent that it
comes into the path of travel of lever 272 of dog 238 as dog 238
rotates through a knotting cycle. Member 294, pivot 296 and relief
spring 306 may collectively be referred to as relief mechanism for
allowing seat 298 to yieldably shift out of its blocking position
of FIG. 3 should the need arise as discussed below.
[0024] Control 256 for clutch 220 further includes an external cam
lobe 310 on the outside surface of ring 242. The high spot on lobe
310 is located approximately 130.degree. from driving lug 240 in
the counterclockwise direction. When driving lug 240 is at pickup
point A in the knotting cycle of revolution, lobe 310 is directly
under roller 290 so as to preclude release of retainer 256.
OPERATION
[0025] As a bale is being formed within the baler 210, the chain
assembly 224 is continuously operating such that sprocket 232 is
continuously rotating. Driving lug 240 is thus also continuously
moving in a circular path of travel about the axis of knotter shaft
222 in a counterclockwise direction. However, as long as dog 238
remains in its disengaged position of FIG. 3, driving lug 240
misses roller 254 of dog 238 during each revolution and thus
maintains clutch 220 in a disengaged condition. Seat 298 of
retainer 276 remains securely beneath lever 272 of dog 238 at this
time, assuring that dog 238 does not flip out to its engaged
position.
[0026] When the bale length sensor 216 trips, and assuming driving
lug 240 is spaced from dog 238 rather than in the immediate
vicinity, linkage 270 pulls the leg 282 of retainer 276 rightwardly
viewing FIGS. 3 and 4 so as to rotate the retainer in a
counterclockwise direction, displacing the seat 298 leftwardly out
from under lever 272 of dog 238. This allows spring 250 to snap
roller 254 out into contacting engagement with the inner surface
242a of cam ring 242 so as to be within the path of travel of
driving lug 240. Therefore, when driving lug 240 reaches pickup
point A, it engages roller 254 of lug 238 and pushes the entire
knotter shaft 222, dog 238 and crank arm 244 in a counterclockwise
direction through one complete 360.degree. operating cycle. During
such cycle, the reset cam flange 292 engages the reset roller 290
and resets retainer 276 in a clockwise direction back into its
retaining position so as to be disposed to engage lever 272 of dog
238 when it returns to pickup point A. This causes dog 238 to be
rotated about pivot 248 to its disengaged position while driving
lug 240 continues along its path of travel.
[0027] In the event that bale length sensor 216 attempts to release
retainer 276 when driving lug 240 is in the immediate vicinity of
dog 238, such release is prevented due to the presence of the
external cam lug 310 which is directly under the roller 290 of
retainer 276 at such time. External lug 310 thus prevents retainer
276 from rocking back in a counterclockwise direction as long as it
is under roller 290. Once external lug 310 has passed by roller
290, retainer 276 is free to release, thus tripping dog 238 to its
engaged position so that driving lug 240 can pick up roller 254 of
dog 238 when lug 240 next reaches pickup point A.
[0028] Normally, conditions are such that once dog 238 is engaged,
lever 272 thereof is rotated counterclockwise about pivot 248 a
sufficient extent that seat 298 will swing in behind lever 272
during any resetting movement of retainer 276 such as might occur
if the external lug 310 were to engage the outside edge of the
roller 290. However, if for some reason, such as tolerance
build-up, timing of the knotter trip, or other causes, the seat 298
does not clear the lever 272 when external cam 310 tends to swing
retainer 276 back toward its retaining position as illustrated in
FIG. 4, relief spring 306 will yield to the extent necessary to
accommodate that situation. Once driving lug 240 then picks up dog
238 and starts to move it counterclockwise, lever 272 will
disengage from seat 298, allowing relief spring 306 to return seat
298 to its blocking position with tail 302 engaged against stop
304. Thus, binding between the retainer 276 and dog 38 is avoided,
which prevents damage to operating components and assures more
uniform bale length.
[0029] FIG. 2 illustrates the binding problem that could sometimes
occur with the prior arrangement in U.S. Pat. No. 5,782,175. As the
roller 88 starts to roll up the ramp 92b of external lobe 92,
retainer 76 is cammed inwardly. Instead of roller 86 passing to the
backside of lever 72, however, it may directly strike the tip of
lever 72. As roller 88 continues up the ramp 92b, binding occurs
and breakage may result. With the spring relief now provided in the
retainer 276 of the present invention, however, this undesirable
situation cannot occur.
[0030] The preferred forms of the invention described above are to
be used as illustration only, and should not be utilized in a
limiting sense in interpreting the scope of the present invention.
Obvious modifications to the exemplary embodiments, as hereinabove
set forth, could be readily made by those skilled in the art
without departing from the spirit of the present invention.
[0031] The inventors hereby state their intent to rely on the
Doctrine of Equivalents to determine and assess the reasonably fair
scope of the present invention as pertains to any apparatus not
materially departing from but outside the literal scope of the
invention as set forth in the following claims.
* * * * *