TUSSOCK-FORMING FOREST CULTIVATOR

Abstract: The invention relates to a tussock-forming forest cultivator, wherein a main beam (3) has rotatably journalled thereto a cultivator means (4) in the form of a multi-pegged wheel. In the travelling path of the points of pegs (5) is fastened a rocker arm (6), having two responsive members (7 and 8) on the opposite sides of a pivot (6a). The turning movement of rocker arm (6) is decelerated by means of a piston-cylinder unit (9) and choke valves (12). The point of each peg (5) strikes first against one responsive member (7) and causes the turning of rocker arm (5) until the peg point slips past responsive member (7) and strikes against the other responsive member (8). The rocker arm turns in the other direction until the peg point slips past the other responsive member (8) as well.

Description: Tussock-forming forest cultivator. The present invention relates to a tussock-forming forest cultivator, comprising a body, a cultivator means journalled rotatably to the body and consisting of a multi-pegged wheel, and a limiter means which is movable between a first and a second position and which momentarily stops or brakes rotation of the cultivator means whenever one of the pegs is directed substantial¬ ly downwards. This type of tussoc -forming forest cultivator and a rotation control system for its cultivator means are disclosed in FI Patent Specification 66273. In this prior known apparatus, hydraulically operated limiter means are positioned near the axis of rotation of a cultivator means. Thus, the limiter means are subject¬ ed to a- great force and problems have occurred in an effort to make both mechanical and hydraulic components of the limiter means sufficiently durable. Thus, the construction of limiter means will be sturdy and ex¬ pensive. Another problem in an apparatus set forth in the cited FI Patent Specification 66273 is that the sequence con¬ trol of the rotation of a cultivator means requires a relatively complicated and expensive electronic control device. FI Patent Specification 34910 discloses a tussock-forming forest cultivator, wherein the limiter means are posit- . ioned near the points of the pegs of a pegged wheel. Although the force exerted on the limiter means will be lesser, there is still no possibility of controlling the size and shape of a cultivated spot and a tussock. These problems are eliminated by means of a forest cul¬ tivator of the invention in a manner that the limiter means comprises a rotatably journalled rocker arm, pro¬ vided with two spaced-apart abutment members .positioned on the opposite sides of a plane extending through the rocking axis and the axis of rotation of a cultivator means whereby, in a first position of the rocker arm, one of the abutment members lies in the travelling path of the point portion of the pegs and the other abutment member is outside said travelling path and, in a second position of the rocker arm, the -latter abutment member lies in said travelling path while the former abutment member is outside the travelling path. The invention will now be described in more detail with ref rence made to the accompanying drawings, in which fig. 1 is a side view of a forest cultivator to which can be attached a sowing apparatus as a special applicatio . Fig. 2 shows the same sowing cultivator in a plan view. Fig. 3 shows a sowing apparatus in a vertical section. Fig. 4 shows a hydraulic and pneumatic operating system for a sowing apparatus. Fig. 5 is a cross-section of a choke valve wherethrough the operating system of fig. 4 receives the hyd¬ raulic fluid required for the operation of a sow¬ ing apparatus whenever the sowing apparatus is attached to a forest cultivator shown in figs. 1 and 2 for its operation. Fig. 6 is a schematic side view of a structurally slight¬ ly modified embodiment of i. forest cultivator. Hereinafter, the invention will be described as a special embodiment with a sowing apparatus attached to a forest cultivator. A forest cultivator shown in figs. 1 and 2 comprises main beams 1 and 3 that can be set at a desired angle relative to each other by means of adjustment plates 2. The rear end of main beam 3 is fitted with a rotatably journalled pegged wheel 4, which serves as a cultivator means and whose pegs 5 are made of spring steel plates. The thin pegs 5 are able to work their way even into a tough turf, whereby the tussock-forming can be effected where mostly needed. In addition to their base attachment, the pegs are braced at their middle portions by means of curved spring plates extending between the pegs in a manner that the contact surfaces of pegs 5 and spring plates are allowed to slide relative to each other when the pegs bend or turn. This pegged wheel structure makes a cultivator light and, thus, a wide variety of tractors can be used; from a farm tractor to a heavy-duty forest tractor (1 to 4 cultivator units per tractor). By re¬ adjusting the angle between main beams 1 and 3 it is possible to change the working angle of a cultivator peg 5. As known in the art, in order to obtain a cultivated spot the rotation of a pegged wheel must be braked at a suitable angle of rotation. In this case, the braking effect is applied in a special way by means of limiter members 7 and 8, responding to the points of pegs 5 and fixed to a rocker arm 6 which is pivotable around an axle 6a. The rod of the piston 10 of a brake cylinder 9 is connected to rocker arm 6. Braking is effected in a manner that, at the I-stage, the peg following a cultivating peg hits the upper limiter member 7 with a result that said rocker arm 6 begins to pivot so that said limiter member 7 moves towards the point of peg 5. However, brake cylinder 9 decelerates the turning of rocker arm 6 since the hydraulic oil can escape from its pressure side through a line 11, a choke valve 12 and a line 13 to provide the operating power for a sow¬ ing apparatus 14. A choke valve 12 is shown in more detail in fig. 5. A pressure line 11 coming from a brake cylinder 9 is connected to a coupling 71 , from which the hydraulic fluid can pass through a pipe 74 to a throttle port 78 controlled by a needle valve 76 to be discharged through a port 73 to which a line 13 is connected. Inside a choke valve body 70 is an axially movable sleeve-shaped member 81, whose outer periphery is provided with an annular groove 82 and which can be urged by means of a pusher 80 against the force of a spring 83. When piston 10 of brake cylinder 9 is displaced a pre¬ determined distance, a lever 6a associated with rocker arm 6 (fig. 2) presses the pusher 80 (fig. 5) fitted in choke valve 12 (I), so that the oil left in the stroke o-c cylinder 9 is released by way of groove 82 to an outlet coupling 72, connected with a line 13 A to sow¬ ing apparatus 14, more particularly to a sowing appa¬ ratus operating circuit fitted with a pressure accumu¬ lator 58 in fig. 4. The spring 83 of choke valve 12 is dimensioned so that the choke valve also serves as a safety valve if inlet pressure becomes too high. Thus, the pressure applied to.the left-hand face of member 81, pusher 80 also lean¬ ing against that face, urges said member 81 against the force of spring 83 until annular groove 82 is located between inlet port 71 and outlet port 72. In addition, the choke valve is self-adjusting due to the fact that a member 77, which is provided with throttle port 78 surrounding valve needle 76, is held by a spring 79 against choke pressure. This compensates to the variat¬ ion in the length of a cultivated spot caused by hard¬ ness of the ground. As the braking effect applied to a peg 5 on hard ground is increasing, the output press¬ ure of brake cylinder 9 is also increasing, said member 77 moving against the force of spring 79 and throttle port 78 being reduced. The length of a cultivated spot can be varied by turning needle valve 76 for moving it inwards or outwards in order to obtain a longer or short¬ er cultivated spot, respectively. When a peg 5 passes by limiter means 7, the cultivating wheel is free to rotate slightly until the same peg strikes against lower stopper means 8. At this time, a peg in the ground reaches a position where it no long¬ er tends to sink deeper into the ground but, instead, finishes a cultivated spot. At this II-stage of form¬ ing a cultivated spot, rocker arm 6 pivots in the di¬ rection opposite to that of stage I and this pivoting is decelerated by piston 10 of brake cylinder 9, which carries hydraulic oil from the cylinder space facing the piston rod by way pressure line 11 (II) and second choke valve 12 (II) into sowing apparatus 14. During the throttling period of choke valve 12, the oil dis¬ charges through line 13 (II) and after the throttling period, when choke valve 12 (II) has shifted to a free running position, the residual oil discharges through line 13 A. In fig. 4 are shown lines 13 (I) , 13 (II) and 13 A through which the sowing apparatus receives its hydraul¬ ic operating power and, at the same time, the timing of automatic operation according to stages I and II of forming a cultivated spot. In reference to figs. 3 and 4, the following descript¬ ion deals with the construction and operation of sow¬ ing apparatus 14. A turf or peat container 16 contains e.g. wetted mass of fertilizer peat. As it rotates, a feed screw 17 squeezes peat mass in the form of a bar or loaf 15a into an orifice 18 which is also the terminal point of a seed duct 21. Thus, the seeds dropped into seed duct 21 are embedded in peat loaf 15a and remain inside a briquette 15 squeezed out of orifice 18. Then, the oil coming into a cylinder 41 at stage I urges a piston 42 down. Piston 42 operates the briquette cut¬ ting and dropping means, designated generally at 50, pressing first a cutting blade 51 downwards for cutting off a briquette 15 and, thereafter, a horizontal plate. 52 at the top of blade 51 meets with plugers 53 of the ■dropping means, the rods connected therewith pivoting around an axle 54 to open the halves 55 of a dropping sleev . A briquette 15 falls onto a cultivated spot through a duct, not shown in the figures. As it presses down, said piston 42 through the inter¬ mediary of a member 43 also presses down the piston of a vacuum cylinder 40 for building a negative pressure required by a seed picker 20 in a. vacuum accumulator 47. As piston 42 continues downwards, a member 44 opens a valve 45 for releasing the pressure from cyl¬ inder 41 to the container, whereby a spring not shown returns piston 42 and also-the piston of pneumatic cylinder 40 up to the outset position, a chain 46 re- closing valve 45 for a new operating cycle. The same operations are repeated at stage II of forming a cultivated spot through the action of a cylinder 61, a piston 62, a valve 60 and a return chain 66. In addition, a valve 59 is coupled with valve 60 to the operating lever 65, to which chain 66 is connected and which is hit by a member 64 in the lowered position of piston 62. The momentary opening of valve 59 relieves pressure from the operating cylinder 31 of feed screw 17 for allowing a piston 32 to return for a new working stroke. This is the only time that the rotation of feed screw 17 is not needed. The rotation of feed screw 17 is effected in a manner that piston 32 rises up through the action of oil charged in pressure accumulator 58 by way of line 13 A, which occurs after both braking stages I and II as the oil flows freely through the choke valve. To the end of piston 32 is journalled a sprocket 33, a chain 34 around it running around a drive wheel 35, 36 and an idle wheel 37. One end of the chain carries a weight 38 and the other end is fastened.to the body at 39. As piston 32 is rising, said chain rotates sprocket 35 and also drive wheel 36 carried thereby. As piston 32 is coming down, sprocket 35 rotates freely around drive wheel 36. This results in a periodical one-way rotat¬ ion ofscrew 17. A pressure in the order of 150 - 200 Pa is obtained in pressure accumulator 58. The seed picker 20 is provided with a vessel 19 for seeds 23, a seed-picking piston 24 fitted in a cylin¬ der 22 having a counter-piston 29 fitting inside said hollow picking piston 24. The picker further includes a seed guide 26 which through the action of a weight 27 swings around an axle 28 to the position shown in fig. 3. The picker operates as follows. At the outset, picking piston 24 rests upon seeds 23, said baffle guide 26 being turned aside. When a valve 49 in a vacuum line 48 (fig. 4) opens, which occurs at the same time as bri¬ quette-cutting mechanism 50 operates, the vacuum pre¬ vailing in cylinder 22 lifts up picking piston 24, whereby a corresponding number of seeds, e.g. two seeds are entrapped in holes 25 at the end surface of the picking piston. As piston 24 continues its rise, said counter-piston 29 works its way inside picking piston 24 developing there a positive pressure which blows the seeds away from holes 25. Prior to that, weight 27 has turned guide or baffle 26 to a position for guiding the falling seeds into seed duct 21. When valve 49 closes (e.g. as briquette-cutting blade 51 rises up) , the vacuum discharges from cylinder 22 through a hole 30 and picking piston 24 descends again on top of seeds 23 and at the same time turns baffle 26 aside. The embodiment shown in fig. 6 is different from that shown in figs. 1 and 2 in that body 3 comprises a one- piece main beam and rocker arm 6 is positioned above pegged wheel on a vertical body portion 160 which can be turned to different angular positions by means of an adjusting rod 150. This substitutes for the relative turning of body portions 1 and 3 in fig. 1. In addition, rocker arm 6 consists of telescopic rods for adjusting the distance of response rollers 7 and 8 from pivot 6a. The body portion 160 provides an oil tank to which valves 12 are fastened. A lever 85 rotating along with pegged wheel 4 relieves the pressure of valve 12 and cylinder 9 just before a peg 5 slips past responsive roller 7 or 8. This saves the peg points and rollers 7 and 8 from wearing. In addition, the height or distance of rocker arm 6 and pivot 6a from pegged wheel 4 is adapted to be ad¬ justed, whereby it is possible to employ pegged wheels with pegs of varying lengths.

Claims: Claims 1. A tussock-forming forest cultivator, comprising a body (3) , a cultivator means (4) journalled rotatably to the body and consisting of a multi-pegged wheel, and a limiter means (6, 7, 8) which is movable between a first and a second position and which momentarily stops or brakes the rotation of cultivator means (4) whenever one of pegs (5) is directed substantially downwards, c h a r a c t e r i z e d in that said limiter means (6, 7, 8) is a pivotably journalled rock¬ er arm having two spaced-apart responsive members (7, 8) disposed on the opposite sides of a plane extending through a pivot (6a)- and the axis of rotation of cul¬ tivator means (4) whereby, in the first position of rocker arm (6), one responsive member (7) lies in the travelling path of the point portion of pegs (5) and the other responsive member (8) lies outside the travel¬ ing path and, in the second position of the rocker arm, the latter responsive member (8) lies in said travel¬ ing path while the former responsive member (7) lies outside the travelling path. 2. A forest cultivator as set forth in claim 1, c h a r a c t e r i z e d in that the delay means limiting or decelerating the movement of responsive members (7, 8) comprise a double-action hydraulic piston-cylinder unit (9, 10) , coupled with rocker arm (6) and having on either side of its piston (10) the cylinder spaces from which hydraulic fluid can dis¬ charge through an adjustable choke valve (12). 3. A forest cultivator as set forth in claim 2, c h a r a c t e r i z e d in that said rocker arm (6) is mechanically (6a) coupled .with throttling adjust- ment means (80) of said choke valves (12) . 4. A forest cultivator as set forth in claim 1 , c h a r a c t e r i z e d in that the hydraulic fluid container for delay means is provided inside body portions (3, 160) . 5. A forest cultivator as set forth in claim 1, c h a r a c t e r i z e d in that said pegs (5) of cultivating wheel (4) are spring-steel strips which, in addition to being secured at their base portions, are braced at their middle portions by means of curved spring plates extending between the pegs in a manner that the contact surfaces of pegs (5) and spring plates are capable of sliding relative to each other when the pegs bend or turn. 6. A forest cultivator as set forth in claim 1 , c h a r a c t e r i z e d in that it is provided with a sowing apparatus (14), comprising: a seed vessel (19) and periodically operating means (20, 26) for picking up a certain number of seeds on each operating cycle from the seed vessel and for carrying such seeds into a seed duct 21. 7. A sowing cultivator as set forth in claim 6, c h a r a c t e r i z e d in that the oil coming out of brake cylinder (9) during and/or after a braking period (arrows I, II and A) is passed to sowing appa¬ ratus operating means (31, 41, 61) whereby said brake cylinder (9) , during its operation, provides both the operating power and action timing for sowing apparatus (14). 8. A forest cultivator as set forth in claim 1 , c h a r a c t e r i z e d in that each pressure line (11) of double-action brake cylinder (9) is connected to its own choke valve (12) . 9. A forest cultivator as set forth in claim 1, c h a r a c t e r i z e d in that said choke valve (12) is fitted with a mechanical pusher (80) for urging the choke valve to an idling position prior to the end of the working stroke of brake cylinder (9) . 10o A sowing cultivator as set forth in claim 6 or 7, c h a r a c t e r i z e d in that seed-picking means (20) comprise a picking piston (24) which by means of vacuum can be lifted up in a cylinder (22) from a po¬ sition where the picking piston rests with its per¬ forated end upon seeds (23) whereby, through the act¬ ion of the vacuum lifting said picking piston (24) , a number of seeds corresponding to the number of holes or perforations are entrapped in seed holes (25) , and that a seed baffle (26) is adapted, while picking piston (26) is rising, to swing itself below said piston so that the seeds falling from picking piston (24) are guided into seed duct (21).

Inventors: SINKKILAE AARRE, SINKKILAE, AARRE
Applicants: SINKKILAE AARRE, SINKKILAE, AARRE
Application year: 1988
Main classification: A01B35
IPC codes: A01B13, A01B49