IE56791B1 - Farm manure scrapers and a hydraulic drive system especially suited therefor - Google Patents

Abstract

The livestock building manure scraper system consists of reciprocating rods (7) with scrapers (11), set lengthwise in the manure channels. The rods have ratchet pawls a which interact with ratchet mechanisms in the scrapers to convert the rods' reciprocating motion into a lengthwise movement of the scrapers which is reversed at the ends of the channels. - The reciprocating motion of the rods is provided by an alternating hydraulic cylinder (3). The cylinder is driven e.g. from a tractor hydraulic system through a distributor (4), or by a separate electric drive unit. (25pp Dwg.No.1/8)

Description

JOSEPH FRANCIS MCGOVERN, A CITIZEN OF THE REPUBLIC OF IRELAND, OF CURRYHILLS PARK, PROSPEROUS, COUNTY KILDARE, REPUBLIC OF IRELAND, AND JOHN JAMES MCGOVERN, A CITIZEN OF THE REPUBLIC OF IRELAND, OF CARTERSTOWL, MONASTERBOICE, COUNTY LOUTH, REPUBLIC OF IRELAND» Λάκ» 90p S67H - 1 Farm manure scrapers and a hydraulic drive system especially suited therefor*1 This application relates to farm machinery, and more particularly to farm manure scrapers and to a hydraulic system which is especially suited for driving such scrapers.

Automatic scrapers are commercially available for cleaning the dung passages of farm buildings such as cowsheds and piggeries.

One leading type of automatic scraper uses a gearbox (driven by an electric motor) having a reduction ratio of 1460 r.p.m. down to 8 r.p.m. at the output shaft. There is a pocket wheel mounted on the output shaft through which a chain is driven. The chain makes an endless circuit along two dung channels and around corner pulleys to pass along both ends of the building. Scrapers are mounted on the chain taking manure to one end of the building and going into an idle position on the return journey. Uhen the scraper arrives at the end where the manure is deposited the direction of rotation of the motor is changed by means of either an overload sensing device or a counting mechanism.

In both cases a fairly complicated electric control box is used to pass the reverse message. It has been found from experience that various parts of this system with the exception of the actual scraper blades are prone to trouble.

Because of the ratio of 1460 to 8, a very high torque 1s produced in the gearbox, putting heavy pressure on gears and bearings. Also, manure Is carried by the chain and deposited at the sprocket and output shaft, eventually getting into the bearings. The gearboxes are vulnerable to breakage and must be replaced. - 2 Owing fo the amounts of electric components used there is high sensitivity to voltage variation. At farm level in rural areas there can be considerable change in voltage levels.

The chain fends to stretch, which requires regular cutting out of 5 pieces to shorten it. Eventually the pitch increases and the links will no longer fit into the pockets in the sprocket wheel* which will require replacement of the chain.

Manure which carries amounts of sand will penetrate the bearings at the pulley wheels causing very rapid wear.

There have been proposals for scrapers operated by a reciprocating drawbar instead of a chain. If is desirable fo drive such a drawbar by hydraulic means, in order to minimise the use of electric apparatus. However the conventional reversing valve for a hydraulic ram has a neutral position between its two end positions (in which fluid is dlr15 ected to one end of the ram or the other). If the valve comes to rest in the neutral position, then reciprocating motion of the piston halts and the ram cannot be operated automatically in a reciprocating sequence.

It is conventional to provide fluid for a hydraulic ram by coupling a hydraulic pump to an electric motor. However this again involves the use Of electric apparatus, which is undesirable.

It is an object of the present invention to overcome these disadvantages.

The present invention provides farm manure scraper apparatus comprising at least one reciprocatable drawbar, a carriage movable along said drawbar, at least one scraper device mounted on the carriage, a ratchet form25 ation on the drawbar, a pawl slidably supported on a pivot on the carriage, the pawl having two teeth which are respectively adapted fo engage the ratchet formation in one of the two directions of movement of the drawbar, and means at each end of the drawbar to change the orientation of the pawl so that one tooth is disengaged from the ratchet formation and the other tooth becomes engaged with it. - 3 Preferably the pawl 1s supported on a horizontal pivot which extends transversely of the carriage and the ratchet formation comprises a series of spaced dogs projecting above the upper surface of the drawbar.

In a preferred embodiment, the pawl is slidable longitudinally relative to the horizontal pivot, and reversing means are provided at each end of the drawbar fo move the pawl longitudinally relative to the pivot so that the pawl overbalances.

The apparatus of this invention is simple and robust. It requires no chains, pulleys or gearbox. It 1s simple to install in a farm building. It does not need the fixing points which are necessary for a chain system9 nor does it require such an even contour on the floor of the dung channel.

The apparatus can if desired be operated electrically. However it is an advantageous feature of the present Invention to operate the reciprocating drawbar by means of a hydraulic ram.

Two embodiments of the invention are illustrated in the accompanying drawings in which: Figure lisa diagrammatic plan view of one embodiment of the apparatus according to the Invention, connected to the hydraulic drive of a tractor; Figure 2 is a plan view of the hydraulic ram reversing mechanism in apparatus similar to that of Figure 1; Figure 3 is an elevation of part of the mechanism of Figure 2, omitting the cylinder, piston and drive bars; Figure 4 is a longitudinal cross section of the scraper installation in the apparatus of Figure 1; Figure 5 is an elevation (to a larger scale) of the pawl in the scraper installation of Figure 4; Figure 6 is an underneath plan view of the pawl of Figure 5; Figure 7 is a transverse cross section of the scraper installation on the line A-A in Figure 4, omitting the pawl and the far end of the drawbar for· clarity. - 4« Figure 8 shows a plan view of a cam mechanism for transmitting reciprocating motion to a drawbar; Figures 9-11 show alternative arrangements of hydraulic ram and drawbars for use with more than one dung channel.

As shot^n in Figure 1, a scraper Installation for the dung channels 8 of a pair of stalls in a cubicle shed for cattle 1s driven from the hydraulic system of a tractor 1 (although another power source, such as a hydraulic pump operated by an electric motor may be used Instead of the tractor® if desired). Hydraulic hose pipes 2 from the tractor are connected to a reciprocating hydraulic ram 3 having a reversing valve 4 which controls the flow of fluid to or from each end of the ram 3 to drive the piston 5 of the ram. The reversing valve 4 1$ operated by a push rod 6 which is oscillated by a device triggered by the reciprocating piston 5® in a manner to be described below* The piston 5 drives a header bar 27 which reciprocates across the head of a pair of dung channels 8® at right angles thereto. The reciprocal movement of the header bar 27 is transmitted fo a pair of drawbars 7 of the scraper mechanism in the two dung channels. Each reciprocating drawbar 7 travels to and fro along the axis of the respective dung channel 8. The drawbar 7 carries a series of dogs 9 spaced along its length. A scraper of the beam11 type is mounted on a carriage 11 which 1s provided with a pawl mechanism to be described below. At each end of the drawbar 7 there is a cam 12 which causes the pawl mechanism fo move from an orientation 1n which it engages on one face of a dog 9 to an orientation in which 1f engages on the other face of the dog and thus reverses the direction of movement of the carriage.

The ram reversing mechanism is shown in greater detail in Figures 2 and 3. The cylinder of the ram 3 is secured by a pin 13 to a channel iron base 14 which in turn is secured (e.g. by bolts) to a concrete sub30 strate. The piston 5 reciprocates in and out of one end of the cylinder. A conventional reversing valve 4 1s mounted on the cylinder. The valve is operated by push rod 6 which extends parallel to the piston 5 and which carries two spaced apart stop-collars 15. The push rod 6 is connected to the spool in the reversing valve. - 5 A lever 16 Is pivoted at its lower end 17 to the base 14 and extends upwardly between the stop-collars 15. At its top end the lever 16 carries a weight 18, and at or near Its mid 86 point 1t is pivotally attached to a trigger wire 19 which carries two fingers 20, the position of which can be adjusted along the trigger wire 19.

The piston carries at Its free end a fixed detent 21. Uhen the piston nears the end of Its outward stroke, the detent 21 engages the outer finger 20a. Continued outward movement of the piston pushes the trigger wire 19 and causes the lever 16 to swing from the position shown In Fig. 2 (In which 1t Is resting against the Inner stop-collar 15b) until the lever 16 passes through dead centre. Because of the weight 18, the lever 16 then falls until if strikes the outer stop-collar 15a. The momentum of the lever pushes the push rod 6 outwardly, causing the spool in the reversing valve 4 to pass from one end position through the neutral position and on to the other end position without stopping in the neutral position. The direction of movement of the piston 5 is thus reversed. It travels Inwardly until the detent 21 engages the Inner finger 20b and pulls the trigger wire inwardly. The lever then passes back through dead centre and falls until 1t strikes the inner stopcollar 15b and pushes the reversing valve to complete the cycle. The weighted lever 16 holds the reversing valve firmly in one end position or the other.

At its free end the piston 5 Is joined by means of a pintle 22 to a transmission bar 23 which extends outwardly parallel to the axis of the piston 5, until It overlaps the Inner end of the header bar 27 which lies in line with the piston 5. A box-shaped housing 24 is secured to one side of the header bar 27 and the transmission bar 23 passes through the housing 24. A shear pin 25 is fixed through the housing 24 and transmission bar 23, to unite the header bar 27 with the transmission bar 23 and thus with the piston 5. However in the event of an obstruction or overload interfering with reciprocating movement of the drawbar 7 and/or the header bar 27, the shear pin 25 will break and disconnect the header bar 27 from the piston 5. - 6 The header bar 27 slides to and fro across the head of the dung channels 8» the header bar 27 being guided in saddles (not shown) which are bolted to the concrete substrate. The header bar is connected to the drawbars 7 by a cam mechanism which 1s described below with reference fo Figure 8.

The outer (or discharge) end of each drawbar 7 extends out of the respective > dung channels 8 across a slurry discharge pit 78, into which the slurry from all of the dung channels is drawn by the scrapers.

• As shown in Figures 4 - 7„ the drawbar 7 of Inverted channel shape slides to and fro on a flat concrete floor in the dung passage 8 which is defined by side walls 67. A series of T-shaped pins or bolts 60 are embedded in to the floor and extend up inside the drawbar. The drawbar has a pair of ribs 61 welded to its Inside surface near fo the free edges. The ribs 61 and bolts 60 co-operate fo retain the drawbar on its track at the longitudinal axis of the channel. On its top surface the drawbar is provided with a series of dogs 9 formed of portions of iron rod welded to the drawbar 7.

The space between the dogs 9 is slightly less (e.g. about 2 inches or 5 cm less) than the stroke of the piston 5.

The carriage 11 for the scraper blades comprises a pair of upright shoes 38 each having a flange base 39 which moves on the concrete floor» the shoes being connected by a portion of the beam 65 of box iron which carries the scraper blades 66. A horizontal transverse axle 31 is formed of a sleeve which fits between the shoes 38 and a shear pin inside the sleeve and extending therefrom at both ends so that it is journalled in holes in the shoes 38.

A pawl 32 slides longitudinally on the axle 31, the limits of sliding movement being defined by teeth 33a and 33b on the lower face of the pawl at its two ends. The pawl has sharply chamfered end faces.

A locking recess 60a9 60b is defined between the inside face of each tooth 33a, 33b and the underneath face of pawl 32.

The pawl 32 comprises a top bar 61 and an under portion 62 which is shorter than the top bar 61 and which is in a centred position so that the top bar - 7extends beyond the underneath bar at each end. The end of the underneath bar then forms a step 64 at the mouth of the locking recess 60as 60b, the step having a chamfered corner 64a and a perpendicular portion 64b. Each tooth 33a, 33b is secured in a bifurcated end portion of the top bar 61.

At each end of the drawbar 7 there 1s a cam 12 comprising an upwardlyinclined surface aligned with the pawl 32. The cam 12 has a stop piece 63b which is a projection which defines an acute angle with the inclined surface of the cam. The upwardly inclined surface changes to a horizontal surface underneath the stop piece 63b.

Alternatively, the cam can be replaced by other means of overbalancing the pawl, or a hydraulic or compressed air cylinder which is compressed by the carriage and then activates another cylinder to tip the pawl.

When the drawbar 7 is moved outwardly (to the right in Figure 4) by the piston 5, the outer tooth 33b on the pawl engages a dog 9 and the Inner tooth 33a acting on the axle 31 causes the carriage 11 to move in the outward direction. Then the drawbar moves inwardly (to the left in Figure 4), the drawbar slides along underneath the tooth 33b until the next dog 9 in the outward direction comes against the tooth 33b and lifts it by swinging the pawl 32 to a snail extent. After the dog has passed underneath the tooth, the tooth drops down forward of the dog and Is ready to engage the dog when the drawbar 7 moves outwardly on the next stroke.

Uith each stroke the carriage 11 is pulled outwardly by a distance equal to the separation of the dogs. When the carriage 11 reaches the end of the drawbar, the chamfered leading edge of the pawl 32 slides up the cam 12b until it is trapped under the stop piece 63b. This lifts the inner end of the pawl relative to the axle 31 by a distance equal to the perpendicular portion 64b of the step 64. Continued movement of the drawbar 7 relative to the carriage then pushes the pawl 32 longitudinally causing the pawl to slide on the axle 31. The axle passes around the chamfered comer 64a and slides relative to the lower surface of the under portion 62 of the pawl. The pawl is pushed on top of the axle 31 until the other tooth 33b has reached the axle. Then as the drawbar motion 1s reversed in the course of Its usual reciprocating action» the cam 12b and stop piece 63b withdraw from the pawl» which overbalances and falls to the opposite orientation to that shown in Figure 4» so that the tooth 33a engages the dogs 9. The axle 31 1s seated in the locking recess 60b and the carriage starts to move in the opposite direction (to the left in Figure 4). When the carriage reaches the cam 12a at the other end of the drawbar (I.e. at the Inner end of the dung passage), the overbalancing procedure is repeated, so that the cycle of outward movement of the carriage begins again.

The carriage 11 carries a scraper of the known beam type. The beam 65 of box Iron Is welded on top of tEie carriage 11» transversely thereto» and extends across the dung channel. Scraper blades 68 are suspended from the beam In conventional manner and flaps 69 are provided af the edges of the beam fo adjust for variations In the side walls of the channel.

The scraper blades 68 are horizontally pivoted so that they will swing towards the outward end of the channel but not towards the inward end of the channel. Therefore during each outward stroke the blades are held in a vertical position and In conjunction with the flaps which slide on the side walls of the channel they push dung to the outward end of the channel and Into the pit 78.

Instead of being formed of a sleeve ami shear pin» the axle 31 may be of plastics or other frangible material» if desired, so that the axle will break in the event of an obstruction or overload.

On the inward stroke, the blades 60 swing loosely towards the outward end of the channel and become inoperative so that a negligible amount of dung is moved towards the Inward end of the channel. The flaps 69 trail loosely on the inward stroke.

The reciprocal movement of the header bar 27 1s suitably transmitted to the drawbars 7 of the scraper installation by a cam mechanism such as that shown 1n Figure 8. The cam mechanism 28 comprises a quadrant or triangular shaped structure 29 (e.g. a metal plate) which is pivoted on a vertical pin 54 at its apex, the pin 54 being secured in the concrete substrate. At another corner of the plate, a wheel is mounted on a vertical pin 53; this wheel is received in a bearing box 50 which is fixed at right angles to the end of the drawbar 7. At the third comer of the plate and extending radially Inwardly therefrom, a second bearing box is constructed on the underside of the plate. This bearing box receives a second wheel mounted on a pin 52 fixed to header bar 27. Movement of the header bar 27 to the right in Figure 8 causes the plate 28 to rotate anticlockwise (as seen in Figure 8) about pivot 54, and the wheel on pin 53 then pushes drawbar 7 inwardly in the dung channel. Movement of header bar 27 to the left 1n Figure 8 likewise causes drawbar 7 fo move outwardly.

If desired, crank arms can be used instead of the arrangement of pivot pins, wheels and bearing boxes described above.

Several cam mechanisms of a similar kind can be attached to header bar 27 along its length in order to reciprocate drawbars 7 in several dung channels.

If desired, one of a series of hydraulic rams can be aligned with each dung channel and can be used to operate one scraper mechanism directly, without the intervention of a header bar 27 and cam mechanism 28.

Figure 9 shows an alternative embodiment in which the ram has its axis parallel to a pair of dung channels and is used to drive a pair of scraper mechanisms by means of a bifurcated transmission framework 81. In this Figure (and in Figures 9 and 10) the scraper is of known delta type in which the scraper blades 10 are vertically pivoted and spread apart across the dung channel on the outward stroke but fold against the carriage on the inward stroke.

Figure 10 shows a further alternative embodiment in which reciprocal movement is transmitted from the ram 3 by a pair of levers 82 pivotally attached to the outer end of the piston 5, the levers being each mounted - 10on a central fixed pivot 83, and being pivotally attached to the outer ends of the drawbars 7 of a pair of scraper mechanisms. Uhen the piston 5 retracts, the levers 82 move to the position shown in dotted outline and draw the drawbars 7 outwardly.

Figure 11 shows an additional embodiment which uses a header bar 27 reciprocating transversely to the drawbars 7, and the cam mechanism comprises a rocker arm 84 which is pivoted to the header bar 27 and also fo the end of drawbar 7.

The present invention provides manure scraper apparatus which is economical to manufacture and to operate. The sliding pawl 1s positive in its engagement function with the dogs due to the fact that the tooth which engages a dog is at the far end of the pawl from the pivot and so almost the whole weight of the pawl acts downwardly on the tooth. This is generally sufficient to cut through any dung or other material which may be lying on or beside the dog. There is little risk of accidental reversal of movement (e.g. by a cow kicking the carriage). The pawl can be removed from the carriage if it is desired to immobilise the scraper in one dung channel while the scraper in an adjacent channel is being operated by a common drive unit. if desired, the beam 65 can be divided info two separate wings attached to the carriage on vertical pivots so that twisting of the beam due fo uneven loads does not cause twisting of the carriage relative to the drawbar.

Claims (7)

1. Farm manure scraper apparatus comprising at least one reciprocatable drawbar, a carriage movable along said drawbar, at least one scraper device mounted on the carriage, a ratchet formation on the drawbar, a pawl slidably supported on a pivot on the carriage, the pawl having two teeth which are respectively adapted to engage the ratchet formation in one of the two directions of movement of the drawbar, and means at each end of the drawbar to change the orientation of the pawl so that one tooth is disengaged from the ratchet formation and the other tooth becomes engaged with it.

2. Apparatus according to claim 1, wherein the pawl is supported on a horizontal pivot which extends transversely of the carriage and the ratchet formation comprises a series of spaced dogs projecting above the upper surface of the drawbar.

3. Apparatus according to claim 1 or 2, wherein the pawl Is slidable longitudinally relative to the horizontal pivot, and reversing means are provided at each end of the drawbar to move the pawl longitudinally relative to the pivot so that the pawl overbalances.

4. Apparatus according to claim 3, wherein the reversing means at each end of the drawbar comprise an upwardly inclined surface to lift the pawl out of engagement with the ratchet formation and a stop to push the lifted pawl relative to the pivot.

5. Apparatus according to claim 3 or 4 θ wherein a recess 1s provided at each end of the pawl on the underside thereof to accommodate the pivot.

6. Apparatus according to claim 5 as dependent on claim 4, wherein the stop on the reversing means Is a projection which defines an acute angle with the upwardly Inclined surface such that the pawl becomes trapped under the stop and the pawl is caused to lift until the pivot becomes disengaged from the recess. - 12

7. Farm manure scraper apparatus substantially as described herein with reference to Figures 3 to 7 of the accompanying drawings.