CA1098757A - Trailing arm mechanism - Google Patents
Trailing arm mechanismInfo
- Publication number
- CA1098757A CA1098757A CA314,773A CA314773A CA1098757A CA 1098757 A CA1098757 A CA 1098757A CA 314773 A CA314773 A CA 314773A CA 1098757 A CA1098757 A CA 1098757A
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- CA
- Canada
- Prior art keywords
- trailing arm
- spring
- arm
- support frame
- pivotal
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Abstract
A B S T R A C T
A trailing arm mechanism is provided for use in an implement such as a spring tine harrow. The trailing arm is pivotally mounted on a support frame and a coil spring normally under tension is connected between the support frame at a point of attachment lower than the pivotal access of the trailing arm and to the underside of the trailing arm remote from the pivotal access. A pair of parallel plates closely spaced from the trailing arm on each side thereof provides constraining lateral support for the trailing arm. The coil spring extends generally parallel to and closely spaced from the underside of the trailing arm. This enables the trailing arm to clear relatively large obstacles on the ground without being impeded by the spring, whose tension increases only slightly for relatively large upward deflections of the trailing arm.
A trailing arm mechanism is provided for use in an implement such as a spring tine harrow. The trailing arm is pivotally mounted on a support frame and a coil spring normally under tension is connected between the support frame at a point of attachment lower than the pivotal access of the trailing arm and to the underside of the trailing arm remote from the pivotal access. A pair of parallel plates closely spaced from the trailing arm on each side thereof provides constraining lateral support for the trailing arm. The coil spring extends generally parallel to and closely spaced from the underside of the trailing arm. This enables the trailing arm to clear relatively large obstacles on the ground without being impeded by the spring, whose tension increases only slightly for relatively large upward deflections of the trailing arm.
Description
109~3757 BACKGROUND OF THE INVENTION
The present invention relates to a spring tine harrow trailing arm or drag arm assembly for use, for example, as an agricultural implement to prepare seedbeds.
It is usual in preparing soil for seeding to drag over the land by means of a tractor or other vehicle, a set of farm implements in tandem such as an assembly of disks followed by an assembly of spring tine harrows. The purpose of the harrow is to break up large clumps of soil and to level the ground. Conventionally, spring tine harrows are comprised of a series of spring loaded teeth or tines mounted on a set of transverse parallel bars with the bars being fixed relative to one another by suitably spaced cross-members clamped or welded to the bars. The resultant assembly of tines is attached by one or more drag arms to a disk, plough, cultivator or other similar unit that operates ahead of and in tandem with the harrow.
Many conventional harrows have either depended upon the weight of the unit itself for downward pressure or have used a coil-spring acting in compression between the drag arm and the support mounting for the drag arm. Such coil-spring units have been susceptible to damage because of the inherent limitation in compression of the spring, consequently limiting the maximum deflection of the harrow upon encountering large objects. In addition, such coil-spring units in encountering large obstacles experience very large downward forces because of the approximately linear increase in compression of the spring with deflection of the drag arm, thereby rendering the aforesaid units more susceptible to damage during such large deflections. Occasionally tension springs have been ~sed, but because of desiqn deficiencies have failed to permit enough deflection of the trailinq arm
The present invention relates to a spring tine harrow trailing arm or drag arm assembly for use, for example, as an agricultural implement to prepare seedbeds.
It is usual in preparing soil for seeding to drag over the land by means of a tractor or other vehicle, a set of farm implements in tandem such as an assembly of disks followed by an assembly of spring tine harrows. The purpose of the harrow is to break up large clumps of soil and to level the ground. Conventionally, spring tine harrows are comprised of a series of spring loaded teeth or tines mounted on a set of transverse parallel bars with the bars being fixed relative to one another by suitably spaced cross-members clamped or welded to the bars. The resultant assembly of tines is attached by one or more drag arms to a disk, plough, cultivator or other similar unit that operates ahead of and in tandem with the harrow.
Many conventional harrows have either depended upon the weight of the unit itself for downward pressure or have used a coil-spring acting in compression between the drag arm and the support mounting for the drag arm. Such coil-spring units have been susceptible to damage because of the inherent limitation in compression of the spring, consequently limiting the maximum deflection of the harrow upon encountering large objects. In addition, such coil-spring units in encountering large obstacles experience very large downward forces because of the approximately linear increase in compression of the spring with deflection of the drag arm, thereby rendering the aforesaid units more susceptible to damage during such large deflections. Occasionally tension springs have been ~sed, but because of desiqn deficiencies have failed to permit enough deflection of the trailinq arm
- 2 -10987~i7 to accommodate relatively large surface obstacles or have been subjected to substantial increases in spring tension when accommodating such obstacles.
Moreover, some existing harrow units generally offer no mechanism for stabilizing the drag arm against ~)98757 lateral movement of the harrow, nor do they provi~e adequate non-slip clamping mechanism for attaching the rearward end of the drag arm to the parallel bars that carry the spring tine support arms. This undesirably permits rotation of the assembly of spring tines relative to the drag arm during operation.
A further problem with many known spring tine harrow units is their complexity of-manufacture, requiring several components of unusual shapes or a relatively large number of components or components of unduly large size of shape, adding unnecessarily to the cost of manufacture and consequently complicating the overall design of the harrow.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a spring-tensioning mechanism for applying downward pressure to a drag arm suitable for use with a spring tine harrow and which allows the drag arm to pass over relatively high obstructions without substantially increasing the downward pressure on the drag arm over that which is exerted on the drag arm during normal operation, and which further permits the drag arm to undergo relatively large deflections without experiencing a spring-imposed limit to its maximum upward deflection.
It is a further object to provide a drag arm mounting mechanism as aforesaid from which to pivotally suspend the drag arm so that the latter is stabilized against lateral movement.
It is a further object to provide a positive non-slip means for clamping the drag arm to the frame supporting the spring tines which also permits lateral adjustment of the spring tines.
~(~98757 The invention is directed to a trailing arm mechanism, comprising:
a support frame;
A trailing arm extending rearwardly from and pivotally mounted about a substantially transverse horizontal axi-s on the support frame and pivotable upwardly from a lower operating position to an upper operating position;
a support frame spring anchoring means fixed to the support frame at a position proximate to and at an elevation lower than the pivotal axis of the trailing arm on the support frame;
a trailing arm spring anchoring means fixed to the trailing arm at a position on the direct underside of the trailing arm remote from the pivotal axis thereof; and a tension coil spring normally under tension located on the direct underside of the trailing arm and connected between the support frame spring anchoring means and the trailing arm spring anchoring means. The spring extends generally parallel to the trailing arm and is closely spaced therefrom. The spring is extensible within its elastic limit from a minimum extension corresponding to the lower operating position of the trailing arm to an extended position reached when the trailing arm pivots upwardly to clear any obstacle lying underneath the arm, such spring extension occurring in a straight line so that the spring does not bend at any time during extension.
The support frame may comprise a pair of ~_ 4 _ . , ,~ ;, .
vertical parallel plates, one on each side of the trailing arm and closely spaced therefrom and extending from the pivotal axis in the direction of the trailing arm to provide lateral support for the trailing arm.
The coil spring in minimum extension may have a length of at least about half the length of the trailing arm.
In the mechanism, the trailing arm spring anchoring means may be spaced downwardly rearwardly from the pivotal axis of the trailing arm.
The mechanism may additionally comprise stop means fixed to the support frame forwardly of the arm spring anchor means underneath the trailing arm and engageable with the trailing arm for limiting the downward pivotal movement thereof.
The invention is also directed to a spring tine harrow for use as an agricultural implement to prepare seedbeds, comprising:
a set of spring tines supported from a harrow frame;
a mounting support;
a trailing arm extending rearwardly from and pivotally mounted about a substantially transverse horizontal axis on the mounting support and extending generally rearwardly therefrom, and pivotable upwardly from a lower operating positon to an upper operating position thereby to permit the tines to clear encountered ground surface obstacles; said trailing arm having means for supporting said tines at the end thereof remote from the pivotal mounting;
- 4a -a tension coil spring normally under tension positioned directly underneath the trailing arm, extending generally parallel to the trailing arm and being closely spaced therefrom, pivotally connected underneath the trailing arm between a first anchor means on the mounting support and a second anchor means located on the trailing arm in a position such that as the trailing arm pivots through a vertical plane, the longitudinal axis of extension of the spring pivots about an axis generally below and offset in a rearwardly direction from the pivotal axis of the trailing arm;
said spring being extensible within its elastic limit from a minimum extension corresponding to the lower operating position of the trailng arm to an extended position reached when the trailing arm pivots upwardly to clear any encountered surface obstacle; the spring always extending in a straight line and not being bent at any time during extension; and means for limiting the downward deflection of the trailing arm below a predetermined point;
said pivotal axis being substantially horizontal.
In the spring tine harrow as defined, the mounting support may be comprised of a pair of parallel plates each mounted in a vertical plane and between which is sandwiched the trailing arm supported by a transverse pivotal connecting means extending between the plates.
In the spring tine harrow as defined, the ~ _ 5 _ ~ ~9~'57 means for supporting the harrow frame on the trailing arm may be comprised of a plurality of U-shaped clamps surrounding a transverse bar of said frame and securing a sheared channel element between the bar and a backing plate fixed to the end of the trailing arm remote from its pivotal axis with the interior portion of the sheared channel element being directed towards and biting into the bar, the bar being fixed to a plurality of tine-supporting arms to which said tines are attached.
SUMMARY OF THE DRAWINGS
Figure 1 is a side elevation view of a preferred embodiment of a spring tine harrow (including trailing arm) assembly in accordance with the present invention.
Figure 2 is an exploded perspective view of the components forming the assembly of Figure 1.
Figure 3 is a side elevation view of the spring tine harrow assembly of Figure 1 shown being pulled over a large obstacle, showing the drag arm and drag arm tensioning spring deflected upwards so as to portray the relative positioning of the deflection limiting cam, drag arm tensioning spring and drag arm.
- 5a -1~39~3757 Figure 4 is a side elevation view of the drag arm mounting support assembly showing different positions of the height positioning cam or adjustment block.
Figure 5 is a side elevation view of the spring tine harrow assembly of Figure 1, showing the drag arm in transport position mode.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT WITH
REFERENCE TO DRAWINGS ~~
The preferred embodiment to be described is a spring tine harrow implement for breaking down clods of soil and levelling the ground in preparation for seeding. However, this description is not to be taken as limiting the trailing arm assembly invention, as the invention would obviously have application to other situations in which a mechanism such as a disk or other device is attached to the end of a drag arm from which it receives a steady down pressure but is capable of deflecting upwards when encountering large obstacles, and subsequently returning to its normal operating position in response to the return force exerted by a spring on the drag arm and in which a simple, convenient, positive means of adjusting the maximum downward deflection of the drag arm is desired.
Referring to Figures 1 and 2, a spring tine harrow attachment (including drag arm assembly) includes a number of spring tines 26, suspended from a number of lateral, substantially horizontal, substantially parallel beam elements 22, 23 and 24, held in place by a rigidly attached frame assembly 21 comprising transverse bar or pipe 33 and parallel spaced side arms 35. Embracing the transverse bar 33 are a number of U-clamps 19 which are bolted to a plate 2 which is welded to the rearmost end of a drag arm 1.
~9l3~57 Between the plate 2 and the transverse bar is a sheared channel element 4 whose sheared edges 37 bite into bar 33 when the U-clamps 19 are tightened, thereby tightly gripping bar 33. It will be noted that the frame 21 can be adjusted transversely relative to drag arm 1 when U-clamps 19 are loosened.
The drag arm 1 is pivotally mounted on a trans-verse bushing 7, which is sandwiched between a balance plate assembly consisting of two substantially parallel vertical plates 3 and 3A, said bushing being supported by a bolt 8, which passes through~the plates and bushing. The plates 3, 3A also extend in a rearwardly direction from the pivotal axis of the drag arm, a short distance over which they are closely spaced from (and thereby constrain the lateral movement of) the vertical sides of the drag arm.
A bolt 15 which passes in a transverse direction through the plates 2, 3 below the level of the pivotal axis of the drag arm and offset from the latter in a rearwardly direction provides a convenient means for anchoring one end of a spring 20 normally under tension, the other end of which is connected to any eye bolt 14 mounted on a bracket 11 welded to the underside of the drag arm.
A bolt 16, also passing in a transverse direction through the balance plates 2, 3, passes through an adjusting block or deflection limiting cam 6, on the axis whose dis-tance to any one of the four abutment surfaces of the cam engageable with drag arm 1 is different from that to any other side. The adjusting block 6 itself is sandwiched between the plates of the balance plate assembly and is positioned below the drag arm offset in a direction rear-wardly of the pivotal axis of the drag arm (but forwardly of spring anchoring bolt 15).
The forward ends 39, 41 of the balance plates 2 and 3 are flanged so as to provide a convenient mounting surface in combination with a mating forwardly positioned clamping plate 5. A transverse beam 43 of an implement frame is sandwiched between plate 5 and flanges 39, 41 bolted to plate 5 above and below the beam 43. (As an alternative construction, plates 3,3A could be formed as an integral U-shaped plate, with flanges 39 and 4i forming an integral surface.) Figure 3 illustrates the upward pivotal deflection of the drag arm 1 and tensioning spring 20 when the harrow has encountered an unusually large object such as rock 31, during operating. Note that a relatively large upward deflection of the drag arm 1 can be accommodated without any limit imposed by the spring 20, which extends longitudinally relatively little for a relatively large upward deflection of drag arm 1.
The adjusting block 6 is shown on Figure 4(a) in a position which provides for the maximum permitted downward deflection of the drag arm 1. The cam 6 is shown on Figures 4(b), (c) and (d) in positions which provide for progressively higher limit levels of permitted downward deflec-tion of the drag arm 1. (In other words, the lowermost per-mitted position of drag arm 1 is lowest in Figure 4(a) and is highest in Figure 4(d), for the cam mounting illustrated.) The bolt 16 supporting cam 6 may also be mounted, instead of through lower holes 45, 46 in plates 2 and 3 as seen in Figures 1, 3 and 4, alternatively through upper holes 47, 48 in these plates. This alternative mounting, illustrated in Figure 5, permits the drag arm 1, during transportation to the field, to be carried in a position where the spring tines do not engage the ground, or the upper holes 47, 48 may be ~19~757 used for shallow draft implements requiring a higher mounting for cam 6. In field operation, the cam 6 is mounted in the preferred mounting position and rotated to adjust the drag arm level so as to allow the spring tines to engage the surface of the ground and penetrate the earth to a desired extent. The entire assembly is pulled forward, usually behind another farm implement such as a disk. The spring tines 26 receive a downward pressure because~of the tension exerted by spring 20 and also by reason of the weight of the assembly.
This downward force causes the tines 26 to engage and till the soil. Although the spring tines 26 themselves deflect to accommodate small surface rocks and other similar objects, when encountering unusually large objects it is necessary for the entire frame 21 to be able to deflect upwards. By minimizing the additional down pressure exerted on the spring tines during large deflections, their susceptibility to damage is considerably reduced. Moreover, during such deflections of the drag arm, the constraining action of the balance plates on the drag arm prevents undesirable lateral motion ---of the spring tine assembly. Finally, in addition to theaforesaid features, the present device enables the drag arm to deflect up and down in a vertical plane without slippage of the frame assembly with respect to the drag arm because of the gripping action of the channel section which is clamped between the adjusting frame assembly and the end plate of the drag arm.
It can be seen that the components illustrated in Figures 1 to 5 are relatively easy to manufacture and assembly in comparison with many prior units, and constitute a relatively compact and lightweight device.
Other obvious variations, modifications and departures from the specific assembly described above will ~987S7 readily occur to those skilled in the art without departing from the spirit of the invention. The scope of the inven-tion is as set forth in the accompanying claims. In the description and claims, words such as "downward", "rearward", "underneath", etc. are to be taken in a relative rather than an absolute sense, since obviously the preferred orientation of the trailing arm assembly may vary, depending upon application.
Moreover, some existing harrow units generally offer no mechanism for stabilizing the drag arm against ~)98757 lateral movement of the harrow, nor do they provi~e adequate non-slip clamping mechanism for attaching the rearward end of the drag arm to the parallel bars that carry the spring tine support arms. This undesirably permits rotation of the assembly of spring tines relative to the drag arm during operation.
A further problem with many known spring tine harrow units is their complexity of-manufacture, requiring several components of unusual shapes or a relatively large number of components or components of unduly large size of shape, adding unnecessarily to the cost of manufacture and consequently complicating the overall design of the harrow.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a spring-tensioning mechanism for applying downward pressure to a drag arm suitable for use with a spring tine harrow and which allows the drag arm to pass over relatively high obstructions without substantially increasing the downward pressure on the drag arm over that which is exerted on the drag arm during normal operation, and which further permits the drag arm to undergo relatively large deflections without experiencing a spring-imposed limit to its maximum upward deflection.
It is a further object to provide a drag arm mounting mechanism as aforesaid from which to pivotally suspend the drag arm so that the latter is stabilized against lateral movement.
It is a further object to provide a positive non-slip means for clamping the drag arm to the frame supporting the spring tines which also permits lateral adjustment of the spring tines.
~(~98757 The invention is directed to a trailing arm mechanism, comprising:
a support frame;
A trailing arm extending rearwardly from and pivotally mounted about a substantially transverse horizontal axi-s on the support frame and pivotable upwardly from a lower operating position to an upper operating position;
a support frame spring anchoring means fixed to the support frame at a position proximate to and at an elevation lower than the pivotal axis of the trailing arm on the support frame;
a trailing arm spring anchoring means fixed to the trailing arm at a position on the direct underside of the trailing arm remote from the pivotal axis thereof; and a tension coil spring normally under tension located on the direct underside of the trailing arm and connected between the support frame spring anchoring means and the trailing arm spring anchoring means. The spring extends generally parallel to the trailing arm and is closely spaced therefrom. The spring is extensible within its elastic limit from a minimum extension corresponding to the lower operating position of the trailing arm to an extended position reached when the trailing arm pivots upwardly to clear any obstacle lying underneath the arm, such spring extension occurring in a straight line so that the spring does not bend at any time during extension.
The support frame may comprise a pair of ~_ 4 _ . , ,~ ;, .
vertical parallel plates, one on each side of the trailing arm and closely spaced therefrom and extending from the pivotal axis in the direction of the trailing arm to provide lateral support for the trailing arm.
The coil spring in minimum extension may have a length of at least about half the length of the trailing arm.
In the mechanism, the trailing arm spring anchoring means may be spaced downwardly rearwardly from the pivotal axis of the trailing arm.
The mechanism may additionally comprise stop means fixed to the support frame forwardly of the arm spring anchor means underneath the trailing arm and engageable with the trailing arm for limiting the downward pivotal movement thereof.
The invention is also directed to a spring tine harrow for use as an agricultural implement to prepare seedbeds, comprising:
a set of spring tines supported from a harrow frame;
a mounting support;
a trailing arm extending rearwardly from and pivotally mounted about a substantially transverse horizontal axis on the mounting support and extending generally rearwardly therefrom, and pivotable upwardly from a lower operating positon to an upper operating position thereby to permit the tines to clear encountered ground surface obstacles; said trailing arm having means for supporting said tines at the end thereof remote from the pivotal mounting;
- 4a -a tension coil spring normally under tension positioned directly underneath the trailing arm, extending generally parallel to the trailing arm and being closely spaced therefrom, pivotally connected underneath the trailing arm between a first anchor means on the mounting support and a second anchor means located on the trailing arm in a position such that as the trailing arm pivots through a vertical plane, the longitudinal axis of extension of the spring pivots about an axis generally below and offset in a rearwardly direction from the pivotal axis of the trailing arm;
said spring being extensible within its elastic limit from a minimum extension corresponding to the lower operating position of the trailng arm to an extended position reached when the trailing arm pivots upwardly to clear any encountered surface obstacle; the spring always extending in a straight line and not being bent at any time during extension; and means for limiting the downward deflection of the trailing arm below a predetermined point;
said pivotal axis being substantially horizontal.
In the spring tine harrow as defined, the mounting support may be comprised of a pair of parallel plates each mounted in a vertical plane and between which is sandwiched the trailing arm supported by a transverse pivotal connecting means extending between the plates.
In the spring tine harrow as defined, the ~ _ 5 _ ~ ~9~'57 means for supporting the harrow frame on the trailing arm may be comprised of a plurality of U-shaped clamps surrounding a transverse bar of said frame and securing a sheared channel element between the bar and a backing plate fixed to the end of the trailing arm remote from its pivotal axis with the interior portion of the sheared channel element being directed towards and biting into the bar, the bar being fixed to a plurality of tine-supporting arms to which said tines are attached.
SUMMARY OF THE DRAWINGS
Figure 1 is a side elevation view of a preferred embodiment of a spring tine harrow (including trailing arm) assembly in accordance with the present invention.
Figure 2 is an exploded perspective view of the components forming the assembly of Figure 1.
Figure 3 is a side elevation view of the spring tine harrow assembly of Figure 1 shown being pulled over a large obstacle, showing the drag arm and drag arm tensioning spring deflected upwards so as to portray the relative positioning of the deflection limiting cam, drag arm tensioning spring and drag arm.
- 5a -1~39~3757 Figure 4 is a side elevation view of the drag arm mounting support assembly showing different positions of the height positioning cam or adjustment block.
Figure 5 is a side elevation view of the spring tine harrow assembly of Figure 1, showing the drag arm in transport position mode.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT WITH
REFERENCE TO DRAWINGS ~~
The preferred embodiment to be described is a spring tine harrow implement for breaking down clods of soil and levelling the ground in preparation for seeding. However, this description is not to be taken as limiting the trailing arm assembly invention, as the invention would obviously have application to other situations in which a mechanism such as a disk or other device is attached to the end of a drag arm from which it receives a steady down pressure but is capable of deflecting upwards when encountering large obstacles, and subsequently returning to its normal operating position in response to the return force exerted by a spring on the drag arm and in which a simple, convenient, positive means of adjusting the maximum downward deflection of the drag arm is desired.
Referring to Figures 1 and 2, a spring tine harrow attachment (including drag arm assembly) includes a number of spring tines 26, suspended from a number of lateral, substantially horizontal, substantially parallel beam elements 22, 23 and 24, held in place by a rigidly attached frame assembly 21 comprising transverse bar or pipe 33 and parallel spaced side arms 35. Embracing the transverse bar 33 are a number of U-clamps 19 which are bolted to a plate 2 which is welded to the rearmost end of a drag arm 1.
~9l3~57 Between the plate 2 and the transverse bar is a sheared channel element 4 whose sheared edges 37 bite into bar 33 when the U-clamps 19 are tightened, thereby tightly gripping bar 33. It will be noted that the frame 21 can be adjusted transversely relative to drag arm 1 when U-clamps 19 are loosened.
The drag arm 1 is pivotally mounted on a trans-verse bushing 7, which is sandwiched between a balance plate assembly consisting of two substantially parallel vertical plates 3 and 3A, said bushing being supported by a bolt 8, which passes through~the plates and bushing. The plates 3, 3A also extend in a rearwardly direction from the pivotal axis of the drag arm, a short distance over which they are closely spaced from (and thereby constrain the lateral movement of) the vertical sides of the drag arm.
A bolt 15 which passes in a transverse direction through the plates 2, 3 below the level of the pivotal axis of the drag arm and offset from the latter in a rearwardly direction provides a convenient means for anchoring one end of a spring 20 normally under tension, the other end of which is connected to any eye bolt 14 mounted on a bracket 11 welded to the underside of the drag arm.
A bolt 16, also passing in a transverse direction through the balance plates 2, 3, passes through an adjusting block or deflection limiting cam 6, on the axis whose dis-tance to any one of the four abutment surfaces of the cam engageable with drag arm 1 is different from that to any other side. The adjusting block 6 itself is sandwiched between the plates of the balance plate assembly and is positioned below the drag arm offset in a direction rear-wardly of the pivotal axis of the drag arm (but forwardly of spring anchoring bolt 15).
The forward ends 39, 41 of the balance plates 2 and 3 are flanged so as to provide a convenient mounting surface in combination with a mating forwardly positioned clamping plate 5. A transverse beam 43 of an implement frame is sandwiched between plate 5 and flanges 39, 41 bolted to plate 5 above and below the beam 43. (As an alternative construction, plates 3,3A could be formed as an integral U-shaped plate, with flanges 39 and 4i forming an integral surface.) Figure 3 illustrates the upward pivotal deflection of the drag arm 1 and tensioning spring 20 when the harrow has encountered an unusually large object such as rock 31, during operating. Note that a relatively large upward deflection of the drag arm 1 can be accommodated without any limit imposed by the spring 20, which extends longitudinally relatively little for a relatively large upward deflection of drag arm 1.
The adjusting block 6 is shown on Figure 4(a) in a position which provides for the maximum permitted downward deflection of the drag arm 1. The cam 6 is shown on Figures 4(b), (c) and (d) in positions which provide for progressively higher limit levels of permitted downward deflec-tion of the drag arm 1. (In other words, the lowermost per-mitted position of drag arm 1 is lowest in Figure 4(a) and is highest in Figure 4(d), for the cam mounting illustrated.) The bolt 16 supporting cam 6 may also be mounted, instead of through lower holes 45, 46 in plates 2 and 3 as seen in Figures 1, 3 and 4, alternatively through upper holes 47, 48 in these plates. This alternative mounting, illustrated in Figure 5, permits the drag arm 1, during transportation to the field, to be carried in a position where the spring tines do not engage the ground, or the upper holes 47, 48 may be ~19~757 used for shallow draft implements requiring a higher mounting for cam 6. In field operation, the cam 6 is mounted in the preferred mounting position and rotated to adjust the drag arm level so as to allow the spring tines to engage the surface of the ground and penetrate the earth to a desired extent. The entire assembly is pulled forward, usually behind another farm implement such as a disk. The spring tines 26 receive a downward pressure because~of the tension exerted by spring 20 and also by reason of the weight of the assembly.
This downward force causes the tines 26 to engage and till the soil. Although the spring tines 26 themselves deflect to accommodate small surface rocks and other similar objects, when encountering unusually large objects it is necessary for the entire frame 21 to be able to deflect upwards. By minimizing the additional down pressure exerted on the spring tines during large deflections, their susceptibility to damage is considerably reduced. Moreover, during such deflections of the drag arm, the constraining action of the balance plates on the drag arm prevents undesirable lateral motion ---of the spring tine assembly. Finally, in addition to theaforesaid features, the present device enables the drag arm to deflect up and down in a vertical plane without slippage of the frame assembly with respect to the drag arm because of the gripping action of the channel section which is clamped between the adjusting frame assembly and the end plate of the drag arm.
It can be seen that the components illustrated in Figures 1 to 5 are relatively easy to manufacture and assembly in comparison with many prior units, and constitute a relatively compact and lightweight device.
Other obvious variations, modifications and departures from the specific assembly described above will ~987S7 readily occur to those skilled in the art without departing from the spirit of the invention. The scope of the inven-tion is as set forth in the accompanying claims. In the description and claims, words such as "downward", "rearward", "underneath", etc. are to be taken in a relative rather than an absolute sense, since obviously the preferred orientation of the trailing arm assembly may vary, depending upon application.
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS
FOLLOWS:
1. A trailing arm mechanism, comprising:
a support frame, a trailing arm extending rearwardly from and pivotally mounted about a substantially transverse horizontal axis on the support frame and pivotable upwardly from a lower operating position to an upper operating position;
a support frame spring anchoring means fixed to the support frame at a position proximate to and at an elevation lower than the pivotal axis of the trailing arm on the support frame.
a trailing arm spring anchoring means fixed to the trailing arm at a position on the direct underside of the trailing arm remote from the pivotal axis there-of, and a tension coil spring normally under tension located on the direct underside of the trailing arm and connected between the support frame spring anchoring means and the trailing arm spring anchoring means, the spring extending generally parallel to the trailing arm and being closely spaced therefrom, said spring being extensible within its elastic limit from a minimum extension corresponding to the lower operating position of the trailing arm to an extended position reached when the trailing arm pivots upwardly to clear any obstacle lying underneath the arm, such spring extension occur-ring in a straight line so that the spring does not bend at any time during extension.
a support frame, a trailing arm extending rearwardly from and pivotally mounted about a substantially transverse horizontal axis on the support frame and pivotable upwardly from a lower operating position to an upper operating position;
a support frame spring anchoring means fixed to the support frame at a position proximate to and at an elevation lower than the pivotal axis of the trailing arm on the support frame.
a trailing arm spring anchoring means fixed to the trailing arm at a position on the direct underside of the trailing arm remote from the pivotal axis there-of, and a tension coil spring normally under tension located on the direct underside of the trailing arm and connected between the support frame spring anchoring means and the trailing arm spring anchoring means, the spring extending generally parallel to the trailing arm and being closely spaced therefrom, said spring being extensible within its elastic limit from a minimum extension corresponding to the lower operating position of the trailing arm to an extended position reached when the trailing arm pivots upwardly to clear any obstacle lying underneath the arm, such spring extension occur-ring in a straight line so that the spring does not bend at any time during extension.
2. A mechanism as defined in claim 1, where the support frame comprises a pair of vertical parallel plates, one on each side of the trailing arm and closely spaced therefrom and extending from the pivotal axis in the direction of the trailing arm to provide lateral support for the trailing arm.
3. A mechanism as defined in claim 2, wherein the coil spring in minimum extension has a length of at least about half the length of the trailing arm.
4. A mechanism as defined in claim 3, wherein the trailing arm spring anchoring means is spaced downwardly rearwardly from the pivotal axis of the trailing arm.
5. A mechanism as defined in claim 2, 3 or 4, additionally comprising stop means fixed to the support frame forwardly of the arm spring anchor means under-neath the trailing arm and engageable with the trailing arm for limiting the downward pivotal movement thereof.
6. A spring tine harrow for use as an agricul-tural implement to prepare seedbeds, comprising:
a set of spring tines supported from a harrow frame;
a mounting support;
a trailing arm extending rearwardly from and pivotally mounted about a substantially transverse horizontal axis on the mounting support and extending generally rearwardly therefrom, and pivotable upwardly from a lower operating position to an upper operating position thereby to permit the tines to clear encount-ered ground surface obstacles; said trailing arm having means for supporting said tines at the end thereof remote from the pivotal mounting:
a tension coil spring normally under tension positioned directly underneath the trailing arm, extend-ing generally parallel to the trailing arm and being closely spaced therefrom, pivotally connected underneath the trailing arm between a first anchor means on the mounting support and a second anchor means located on the trailing arm in a position such that as the trailing arm pivots through a vertical plane, the longitudinal axis of extension of the spring pivots about an axis generally below and offset in a rearwardly direction from the pivotal axis of the trailing arm; said spring being extensible within its elastic limit from a minimum extension corresponding to the lower operating position of the trailing arm to an extended position reached when the trailing arm pivots upwardly to clear any encoun-tered surface obstacle; the spring always extending in a straight line and not being bent at any time during extension;
means for limiting the downward deflection of the trailing arm below a predetermined point;
said pivotal axis being substantially hori-zontal.
a set of spring tines supported from a harrow frame;
a mounting support;
a trailing arm extending rearwardly from and pivotally mounted about a substantially transverse horizontal axis on the mounting support and extending generally rearwardly therefrom, and pivotable upwardly from a lower operating position to an upper operating position thereby to permit the tines to clear encount-ered ground surface obstacles; said trailing arm having means for supporting said tines at the end thereof remote from the pivotal mounting:
a tension coil spring normally under tension positioned directly underneath the trailing arm, extend-ing generally parallel to the trailing arm and being closely spaced therefrom, pivotally connected underneath the trailing arm between a first anchor means on the mounting support and a second anchor means located on the trailing arm in a position such that as the trailing arm pivots through a vertical plane, the longitudinal axis of extension of the spring pivots about an axis generally below and offset in a rearwardly direction from the pivotal axis of the trailing arm; said spring being extensible within its elastic limit from a minimum extension corresponding to the lower operating position of the trailing arm to an extended position reached when the trailing arm pivots upwardly to clear any encoun-tered surface obstacle; the spring always extending in a straight line and not being bent at any time during extension;
means for limiting the downward deflection of the trailing arm below a predetermined point;
said pivotal axis being substantially hori-zontal.
7. A spring tine harrow as defined in claim 6 wherein the mounting support is comprised of a pair of parallel plates each mounted in a vertical plane and between which is sandwiched the trailing arm supported by a transverse pivotal connecting means extending between the plates.
8. A spring tine harrow as defined in claim 7 wherein said means for supporting the harrow frame on the trailing arm is comprised of a plurality of U-shaped clamps surrounding a transverse bar of said frame and securing a sheared channel element between the bar and a backing plate fixed to the end of the trailing arm remote from its pivotal axis with the interior portion of the sheared channel element being directed towards and biting into the bar, the bar being fixed to a plurality of tine-supporting arms to which said tines are attached.
9. A mechanism as defined in claim 6, 7 or 8 wherein the coil spring in minimum extension has a length at least about half the length of the trailing arm.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US84999177A | 1977-11-09 | 1977-11-09 | |
| US849,991 | 1977-11-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1098757A true CA1098757A (en) | 1981-04-07 |
Family
ID=25307003
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA314,773A Expired CA1098757A (en) | 1977-11-09 | 1978-10-31 | Trailing arm mechanism |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1098757A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR3006342A1 (en) * | 2013-06-03 | 2014-12-05 | Guenneau Traveaux Publics Transp | DEVICE FOR THE COLLECTION OF SEAWEED ALGAE ON ENABLED SURFACES |
| CH713217A1 (en) * | 2016-12-09 | 2018-06-15 | Martin Umwelt & Energietech | Attachment for a working machine, in particular for an excavator. |
-
1978
- 1978-10-31 CA CA314,773A patent/CA1098757A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR3006342A1 (en) * | 2013-06-03 | 2014-12-05 | Guenneau Traveaux Publics Transp | DEVICE FOR THE COLLECTION OF SEAWEED ALGAE ON ENABLED SURFACES |
| CH713217A1 (en) * | 2016-12-09 | 2018-06-15 | Martin Umwelt & Energietech | Attachment for a working machine, in particular for an excavator. |
| EP3336263A1 (en) * | 2016-12-09 | 2018-06-20 | Martin GmbH | Attachment for a working machine |
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| MKEX | Expiry |