Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to adaptor assemblies for enabling
a three point type trailing unit to be towed behind a draft vehicle having
a single point towing connector, and more particularly to such units
having a lifting mechanism selectively operable to raise or lower the
attached implement while providing support in the raised position.
Modern agricultural technology has led to the development of
implements to be towed behind a draft vehicle in ground working opera-
tions that are extremely large and equally heavy. Transportation of
such implements is becoming increasingly difficult, especially along
roadways to and from fields. In addition, such heavy implements when
utilized in the field, are or~in~rily too heavy to lift into an inopera-
tive position without producing an often dangerous imbalance to the tow-
ing vehicle. Further still, it has become desirable to provide some
type of mechanism whereby a large crawler type tractor having a single
pintle type towing hitch may be operatively connected to a ground
working implement having a conventional thTee point hitch assembly.
The present invention was designed in order to alleviate the
above problems by providing both an adaptor to fit intermediate a single -
point hitch towing vehicle and a three point hitch trailing implement
with the added provision of means for elevating the implement to an
above ground inoperative position. The present invention further includes
provisions for supporting the implement in a raised position without
transmitting an excessive load to the tow m g end of the draft vehicle.
An adaptor assembly is described for connecting a three point
hitch implement to a single point hitch draft vehicle. The adaptor
assembly includes a first framework with a forward connector member
thereon for operative engagement with a complementary hitch member of
the draft vehicle. A secondary wheel supported framework is mounted to
the first framework for pivotal movement about a horizontal pivot axis.
The secondary framework includes rearwardly facing three point hitch
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connectors thereon for operative engagement with complementary connectors -
of the three point hitch implement. A jack means interconnects the first
and secondary frames and is operable to pivot the three point connectors
and an implement attached thereto relative to the first framework between
(a) a first position wherein the implement is held in an operative ground
engaging condition and (b) a second position wherein the implement is :
lifted from the ground and is suppor~ed directly by the adaptor assembly.
Fig. l is an isometric pictorial view of a first embodiment of
the present invention; ~.
Fig. 2 is a partially fragmented side elevational view;
Fig. 3 is a longitudinal section view similar to Fig. 2 only
showing a different operational relationship of the elements therein;
Fig. 4 is a plan view of the drawbar assembly;
Fig. 5 is a fragmented section view taken substantially along ~-
line 5-5 in Fig. 3;
' Fig. 6 is a plan view of a second embodiment of the drawbar
assembly;
Fig. 7 is a sectional view taken along line 7-7 in Fig. 6;
Fig. 8 is a sectional view taken along line 8-8 in Fig. 6; and
Fig. 9 is an enlarged pictorial view of a portion of the
present device.
Description of First Embodiment
A first form of the present drawbar adaptor assembly is illus-
trated by the accampanying drawings in Figs. 1 through 5 and is generally
designated therein by the reference character 10. Drawbar adaptor assem-
bly 10 is utilized to adapt a trailing implement ~not shown) such as con-
ventional agricultural ground working tools to a draft vehicle. Ordinar-
ily, ground working implements include a three point hitch connector assem- -
bly that is adapted to be connected to a complementary set of connectors
on a draft vehicle. However, not all draft vehicles include three point
connectors, but rather include a single point hitch member as shown at 14
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(Figs. 2 and 3). It is well understood however that the present assembly
could be as easily constructed to enable its adaptation to either a sin-
gle poin~ or a three point hitch connector of a draft vehicle.
The present assembly 10 includes a forward hitch member 12 ~-
operatively engageable with a complementary hitch member 14 of the -;
draft vehicle.
The hitch member 12 is pivotably mounted at the forward tongue
end of a first framework 18. The pivot connection between frame 18 and
member 12 allows some freedom of movement vertically between the towing
hitch member 14 and trailing hitch member 12. The tongue portion of -
framework 18 is indicated at 13. Tongue portion 13 may be extensible,
all~wing an operator to select the distance between the towing vehicle -
and trailing implement. A secondary framework 20 is mounted to first
framework 18 and includes wheels 17 thereon for supporting nearly all
the weight of the assembly plus the weight of an attached implement.
As may be noted in Figs. 2 and 3, the secondary framework 20
pivots about late~ally spaced aligned pivot hinges 22. Three point
connectors 19, l9a and 19_ are provided at a rearward frame end to receive
complementary connectors 21, 21a and 21b of a trailing implement. The
lower connectors are located below the hinge axis in a first operative
position and above the axis in a second inoperative position.
The wheels 17 are mounted to a transverse axle 23. Axle 23 is
comprised of several transverse telescoping channel members 24 as shown
in Fig. 5. A wheel hub 25 is unted at either end of axle 23 to receive
single or dual wheels 17 as shown in Fig. 4. It should be noted particu-
larly with reference to Figs. 2 and 3, that the rotational axis of wheels ~
17 is offset from the axis of the pivot hinges 22. This is an operational -provision and will be discussed in greater detail later on in the specifi~
cation.
The wheels 17, through provision of extensible channels 24,
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~ may be selectively spaced apart to facilitate greater stability while- plowing or performing other field working procedures. When drawn
together to a compact position as shown in the drawings, the wheels ~ ,
enable transport along highways or narrow roads.
A jack means 27 is provided intermediate the secondary :'
framework 20 and central fTamework 18 and is operable to pivot the
secondary framework 20 about the horizontal axis of hinges 22. Jack
means 27 operates to selectively move the secondary framework and an
implement attached thereto between the operative position (Fig. 2) and `
- 10 the inoperative elevated position (Fig. 3). Jack means 27 includes ahydraulic cylinder 28. Cylinder 28 is connected at a rearward end 29
to the fiTst central framework 18. A ram end 30 of c~linder 28 is
connected to the remainder of the jack assembly. The remaining elements
of jack means 27 include a lever arm 31 pivotally mounted to framework
18, and a triangular connecting beam 34 extending between the lever arm `
31 and secondary fTamework 20.
Lever arm 31 is centrally located on framework 18 and is
pivotally held for movement about a pivot 32. It may be noted in Figs. 2
and 3 that a plane containing the pivot axis of hinges 22 and of pivot 32
is parallel to a horizontal ground plane. The connecting beam 34 is
pivotally unted at one end by a pivot 33 to lever arm 31. The remain-
ing end of connecting beam 34 is mounted to secondary framework 20 by a
pair of coaxial pivots 36. Pivots 33 and 36 also lie within a horizontal
plane and are longitudinally spaced apart by a distance equal to the
longitudinal distance between the pivot 32 and hinges 22. This defines a
parallelogram type linXage whereby angular pivotal movement of lever arm
31 will result in an equal corresponding angular movement of secondary
framework 20 about the axis of hinges 22.
Connecting points 19, l9a and 19_ are provided at the rearward
end of assembly 10 by the secondary frameworX 20 and by a linXage means
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35 extending from front to rear of the complete assembly. The lower
laterally spaced connectors 19 and I9a are formed integrally with the
secondary framework 20. These co~necting points are shown to best advan-
tage by Figs. 2, 3 and 4. The upper connecting point l9b is located only
by the relative position of the upper connector member 21b of the asso-
ciated implement. This is so because the upper connecting point of assem-
bly lO is loosely held by a cable 37 between the framework 18 and second-
ary framework 20. Cable 37 forms a part of linkage means 35. Linkage
means 35 also includes a sheave 38 and shock absorbing means 40. The
shock absorbing means 40 is pivotally mounted toward the forward end of
framework 18. Cable 37 extends rearwardly from means 40 and over sheave
38. Sheave 38 is held by a clevis 39 that is connectable to the hitch
point 21b of the towing vehicle. The cable 37 then extends forwardly
toward lever arm 31 where it is connected for movement therewith. -~
Shock absorbing means 40 includes a relatively strong com-
pression spring 42 and a plunger member 43 that is secured to cable 37.
Tension applied to the cable 37 will Tesult in compression of spring 42
within its cylindrical canister 41 holder. Therefore, as the jack means
is operated to move the implement to the raised position, the cable 37
is also actuated to draw the connecting points l9b and 21b rearwardly.
The primary purpose of compression spring 42 is to compensate for road
shocks when the implement is being carried in the inoperative position.
RatheT than providing a rigid connection that would transfer objection-
a'ole movement to the implement, such undesired movement is taken up as
spring 42 compresses and extends under the levered weight of the trail-
ing implement.
In order for operation, the pTesent assembly must first be
attached to a towing vehicle with its hitch member 14 operatively
engaging the hitch member 12 of the present assembly. When thus c~nnected, -~
the assembly is backed into position in contact with the three point
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: hitching elements 21, 21a and 21_ of a selected implement. The corres-
ponding hitch points l9, l9a and l9b and 21, 21a and 21b are then joined,
and cylinder 28 is connected to the hydraulic pressu~e supply of the
draft vehicle.
~o elevate the implement then for highway travel, the jack
means 27 is operated, extending cylinder 28. This motion results in
corresponding pivotal movement of the parallelogram linkage defined by
lever arm 31 and connecting beam 34, along with secondary framework 20
and framework 18. The forward pivotal m wement of jack means 27 results ~- `
in corresponding pivotal movement of the secondary framework about the
axis of hinges 22. As shown in Fig. 3, this movement also results in
upward pivotal movement of the lower hitch points 19, l9a to the location
- shown in Fig. 3. It should be noted that the amount of elevational move-
ment of hitch points 19, l9a is effected not only by their rotational
movement about the axis of hinges 22, but also by the pivotal movement
of the wheel axis about the axis of hinges 22. Thus, as the secondary
frame is pivoted, the hitch points 19, l9a are raised relative to frame-
work 18 and framework 18 is raised simLltaneously relative to the
ground.
While jack means 27 is operating to elevate the lower hitch
points, the linkage means 35 operates simultaneously in response to the
jack means to pull the upper hitch point forwardly. This movement
results as the lever arm 31 pulls against cable 37. Thus, through
linkage means 35, the upper implement connector 21b is pulled along an
upright arcuate path forwardly to tip the implement upwardly as it is
being raised by frame connectors 19 and l9a. If a rigid connection is -
made between the three point connectors and the implement, the implement
will be raised to an elevated condition and supported only through the
wheels 17 and forward hitch 12. Therefore, the vertical downward load of
the implement is not transferred to the rearward end of the towing vehicle.
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Rather, the weight operates across the wheel axis (which functions as a
fulcrum) to actually produce a small amount of lift to the rearward end
of the draft vehicle.
To move the implement back to an operative position as shown in
Fig. 2, the cylinder 28 is actuated to retract. This movement causes the
corresponding elements including secondary framework 20 to pivot rear-
wardly In doing so, the lower connecting points are pivoted downwardly
about the axis of hinges 22 and the wheel axis is pivoted simultaneously
- upwardly and forwardly. Purther, as the lever arm is pivoted rearwardly,
the cable 37 is allowed to release tension on the sheave 28 and compres-
sion spring 42, allowing the upper connecting point to return to a normal
position.
Description of Second Embodiment
A second form of the present drawbar adaptor assembly is ~ ;
illustrated by the accompanying drawings in Figs. 6 through 9 and is
generally designated therein by the reference character 110. It includes
a forward hitch member 112 operatively engageable with a complementary
hitch member 114 of the draft ~rehicle.
The hitch member 112 is pivotably mounted at the forward tongue
end of a first framework 118. The pivot connection between frame 118 and
member 112 is provided to enable relative movement between the assembly
and towing vehicle about a horizontal axis. The tongue portion of
framework 118 is indicated at 113. Tongue portion 113 may be extensible,
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allowing an operator to select the distance between the towing vehicle
and trailing implement. A secondary framework 120 is mounted to first
framework 118 and includes wheels 117 thereon for supporting nearly all
the weight of the assembly plus the weight of an attached implement.
As may be noted in Figs. 7 and 8, the secondary framework 120
pivots about laterally spaced aligned pivot hinges 122. Three point -
connectors 119, ll9a and ll9b are provided at a rearward frame end to
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receive complementary connectors 121, 121a and 121b of a trailing
implement.
The wheels 117 are mounted to a transverse axle 123. Axle
123 may be comprised of several transverse telescoping channel members
124 as shown in Fig. 8. A wheel hub 125 is mounted at either end of
axle 123 to receive single or dual wheels 117 as shown in Fig. 9.
A jack means 127 is provided intermediate the secondary
framework 120 and the first framework 118 and is operable to pivot the
secondary framework 120 about the horizontal axis of hinges 122. Jack
means 127 operates to selectively move the secondary framework and an
implement attached thereto between the operative position (Fig. 7) and
the inoperative elevated position (Fig. 8). Jack means 127 includes a
hydraulic cylinder 128. Cylinder 128 is connected at a rearward end 129
to the first central framework 118. A ram end 130 of cylinder 128 is
connected to the remainder of the jack assembly, The remaining elements
of jack means 127 include a lever arm 131 pivotally mounted to framework
118, and a triangular connecting beam 134 extending between the lever
arm 131 and seconda~y framework 120.
Lever arm 131 is centrally located on framework 118 and is
pivotally held for movement about a pivot 132. It may be noted in Figs.
7 and 8 that a plane containing the pivot axis of hinges 122 and of ~ -
pivot 132 is parallel to a horizontal ground plane. The connecting beam
134 is pivotally mounted at one end by a pivot 133 to lever aTm 131. The
remaining end of connecting beam 134 is mounted to secondary framework
120 by a pair of coaxial pivots 136.
Connecting points 119, ll9a and ll9b are provided at the rear-
ward end of assembly 110 by the secondary framework 120 and by a linkage
means 135 extending from front to rear of the complete assembly. The
lower laterally spaced connectors 119 and ll9a are formed integrally
with the secondary framework 120. These connecting points are shown to
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best advantage by Figs. 7, 8 and 9. The upper connecting point 119_
is located only by the relative position of the upper connecting member
121_ of the associated implement. This is so because the upper connect-
ing point of assembly 110 is loosely held by a cable 137 between a load
relieving assembly 139 (described below) and secondary framework 120.
Cable 137 extends rearwardly from shock absorbing means 140
and over sheave 138. The cable wraps about sheave 138 and then extends
forwardly to the load relieving assembly 139.
Shock absorbing means 140 includes a relatively strong com-
pression spring 142 and a plunger member 143 that is secured to cable
137. Tension applied to the cable 137 will result in compression of
spring 142 within its cylindrical canister 141. Therefore, as the jack ;
means is operated to move the implement to the raised position, the
cable 137 will draw the connecting points ll9b and 121_ rearwardly.
The primary purpose of compression spring 142 is to compensate for road
shocks when the implement is being carried in the inoperative position.
Undesired shock loads between the implement and assembly 110 are taken
up as spring 142 compresses or extends under the levered weight of the
trailing implement.
The load relieving assembly 139 is provided to transfer part
of the static load of the implement ~when it is carried in the second
position) to the towing vehicle. This load is produced by the implement
which is cantilevered rearwardly from the connectors 119, ll9a and ll9b.
; Normally the cantilevered weight of the implement would operate through
the wheel axis to produce a static upward moment directed through the
tongue 113 against hitch members 112 and 114. Much of this load is
transferred through the present assembly 139 directly to the tractor -
frame. This is done through the interconnection of cable 137 and load
relieving means 139. A tongue stabilizing means 143 is also provided in
conjunction with the load relieving means to react against the upward
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moment of tongue 113 by providing a reactionary downward force through
a stabilizer brace 144.
The load relieving means 139 includes a bracket means 148
that is adapted to be fixed to the towing vehicle framework forward of
its hitch member 114. Bracket means 148 includes a base 149 and an
elongated tubular channel 150 extending therefrom. The channel 150
slidably receives a telescoping a~m 151. AIm 151 is adjustably posi-
tioned within tubular channel 150 through a selectively removable pin
153 that may be received within any one of several spaced apertures 154
formed through the arm 151. Provision of the pin 153 and spaced aper-
tures 154 enables longitudinal adjustment of the effective length of the
bracket means to facilitate mounting of the assembly on different models
of towing vehicles.
An upper end 152 of the telescoping arm 151 is mounted through a
pin 155 to a clevis 156. The clevis is an integral part of both the `
load relieving means 139 and tongue stabilizer means 143. Clevis 156 is
connected directly to an end of cable 137 through a cross pin 157. Thus,
moment produced at the upper connector ll9b is transmitted through the
cable 137 directly to the towing vehicle frame.
It may be noted that the pin 155 is in coaxial alignment with
the corresponding pin 158 that interconnects the hitch members 112 and
114. This arrangement allows free relative movement of the towing
vehicle and trailing assembly and implement about the pin axis. Although
slight misalignment may occur, the pins are held sufficiently coaxial
to prevent binding when the towing vehicle turns.
The tongue stabilizer means 143 includes the stabilizer brace
144 as briefly described above. Brace 144 includes a low0r brace end
160 that is bifurcated with dcwnwardly projecting ears 162. A pin 161
extends horizontally through each ear 162 and correspondingly through
the forward tongue end and hitch member 112. Thus, all three elements
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(tongue 113, brace 144, and connector member 112) are pivoted about
the same axis as defined by pin 161.
The shock absorbing means 140 is connected to cable 137 to
effectively relieve sudden shock loads delivered through connector
member ll9b to the towing vehicle framework and drawbar assembly 110.
It should be noted however that the placement of means 140 is not
restricted to the specific location shown in the drawings. It is under-
stood that the positioning of means 140 could be such that the pin 157
would mount a rearward end of the canister 141 and cable 137 would ;
extend from the canister, over sheave 138 and subsequently forwardly
to the upper end of lever 131.
- In general, the operation of this second embodiment is similar
to the operation described with reference to the first embodiment.
However, it indirectly transfers a part of the static load on the tongue
to the frame of the towing vehicle when the implement is in a canti-
levered position. This is accomplished through use of the load
relieving means 39. ~
The vertical downward load of the implement acts as a force ` ~;
against a fulcrum at the axes of hitch points 119, 119_ to produce
strong rearward moment at hitch point ll9b. The directional force at ~ -
119_ is transmitted through caole 137 partly to the tongue 112
tthrough lever 131) and partly to the towing vehicle frame through
provision of the load relieving means 139. Thus only a portion of the
total force produced through hitch point ll9b is transmitted through
the tongue 113 to the interconnected hitching members 112 and 114.
Further, since the force (through lever 131) is applied at a point near
the wheel axis, the resulting vertical moment at the forward tongue end -
is nearly negligible.
The tongue stabilizer means 143 operates to hold the pin 161
in relatively stationary horizontal alignment with the interconnected
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hitch members 112 and 114. Therefore, when the towing vehicle and
assembly are angularly misaligned (as when the vehicle moves over the
crown of a hill with the wheel 117 not yet reaching the crownl, the
connected hitch ~embers 112 and 114 will not bind. Instead, the assembly
and draft vehicle will articulate about pin 161.
Shock loads which may be imparted to the tongue 113 through
bouncing of the implement when carried in the second inoperative posi-
tion, are met by an opposed vertical reaction force presented through -~
the stabilizer brace 144 against pin 161.
lhe pin 155 interconnects the bracket 148 and brace 144 to
allow relative turning of the implement and assembly 110 in a horizontal
plane. The axis of pins 155 and 154 are maintained relatively coaxial
for this purpose. ,
The above description and attached drawings describe only
two preferred forms of our invention. It is well understood that various
changes can be made therefrom without departing from the scope of this ~ ;
invention. Therefore, only the following claims are to be taken as
restrictions placed upon the scope of our invention. -
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