GB2097841A - Method of and apparatus for harvesting peat - Google Patents

Abstract

Known peat harvesting apparatus for mounting on an agricultural tractor comprises (a) a digging chain for insertion into and movement across a bog so as to form a groove, and (b) a peat extrusion press. The invention provides; a method in which a groove (204) inclined to the vertical is formed, which is subsequently closed over by downward pressure of the tractor wheel (202) thereby conserving bogland; a roller (107) above the digging chain (104) to prevent the apparatus clogging; a single drive transmission connecting both digging chain (104) and extrusion press (105) to the tractor power take-off shaft; and a macerating mechanism in the extrusion press (105) which allows extrusions of relatively small cross section to be produced. <IMAGE>

Description

SPECIFICATION Method of and apparatus for harvesting peat The present invention relates to the harvesting of peat.

A known method of harvesting peat uses a harvesting device in the form of an endless toothed cutting chain. The harvesting device is inserted downwardly to effect a deep incision in the bog. The device is then moved through the bog forming a long, deep and narrow groove. The groove is sufficiently narrow to close in naturally.

The known method extracts peat from deep within the bog while at the same time preventing waterlogging and conserving bogland.

Known apparatus for harvesting peat comprises; a support frame forming part of, or mounted on, a prime mover, such as a tractor, adapted to move across the surface of a bog; a peat digging device such as a digging chain, pivotally mounted on the support frame so that the digging device may (a) be lowered into an operational position in the bog, and (b) be raised into an inoperational or transport position above the surface of the bog; and a housing in which the dug peat is collected, the housing containing peat handling means such as an extrusion press.

Such peat cutting apparatus will hereinafter be referred to as "apparatus of the type described".

A particular apparatus of the type described has a digging chain comprising an endless toothed cutting chain mounted on two spaced apart sprockets fixed in a blade, a drive sprocket at the end of the blade adjacent the support frame and an idler sprocket at the free end of the blade. The support frame is adapted to be mounted on a tractor, and comprises two subframes, a first subframe (the stationary subframe) for attachment to the tractor so as to remain stationary relative thereto, and a second subframe (the movable subframe) attached to the stationary subframe, and pivotally movable relative thereto.

British Patent Specification No. 764,365 (Ab Hissfabriken), discloses an apparatus of the type described in which the housing and cutting chain are both fixedly mounted on the pivotally movable subframe, and pivot together about a common pivotal axis so that the relative orientation of the cutting chain and housing is fixed. The peat handling means, in the form of an extrusion press, and the cutting chain, are both driven from the stationary subframe by means of two drive transmission arrangements comprising a first drive transmission, in the form of a drive chain and sprockets, connecting the stationary subframe to the extrusion press, and a second drive transmission, also in the form of a drive chain and sprockets, connecting the extrusion press to the digging chain.

In the known apparatus, the digging chain is located to one side of the housing. The cut peat is delivered from the digging chain to the housing by means of a canopy and funnel arrangement, the canopy covering the top of the chain, and the funnel leading from the canopy to the housing.

The digging chain must be driven at high speed to provide the peat with sufficient impetus to pass via the canopy and funnel to the housing. The high speed operation significantly reduces the working life of the digging chain. Furthermore, cut peat hurled against the underside of the canopy tends to stick to the canopy surface and to accumulate, clogging the apparatus.

One prior proposal, contained in British Patent Specification No. 764,365 (Ab Hissfabriken), is to apparatus of the type described, in which the top of the digging chain projects into the housing, eliminating the need for a canopy and funnel. A large gap is left between the top of the digging chain and the underside of the roof of the housing to prevent accumulation of peat.

Peat extrusion presses are known which comprise an axially symmetric (for example cylindrical) housing, a larger entry aperture at one end of the housing through which cut peat enters the housing, an auger mechanism within the housing for driving the cut peat towards the other end of the housing, and a smaller exit aperture at the other end of the housing, through which the peat is extruded onto the surface of the bog to dry.

Such a peat extrusion press will hereinafter be referred to as "a peat extrusion press of the kind described".

British Patent Specification No. 764,365 (Ab Hissfabriken) provides a peat extrusion press of the kind described, forming part of apparatus of the type described, and provided with a single exit aperture through which all the peat is extruded as a single extrusion.

The present invention provides a method of harvesting peat in which an elongate digging device is inserted downwardly into a bog and then moved through the bog, thereby forming a long, deep and narrow groove, characterized in that (a) the digging device is inserted at an angle to the vertical plane through the line of travel of the digging device, thereby forming an inclined groove, and in that (b) the inclined groove is subsequently closed by pressing downwardly on the bog surface above the groove so formed.

The invention also provides apparatus for use in connection with the method.

The invention also provides apparatus of the type described in which (a) the peat cutting device is an endless toothed digging chain having a drive sprocket at the end adjacent the support frame and in which (b) the housing and digging chain are both fixedly mounted on a first sub-frame (the movable subframe) which is pivotally movable relative to a second subframe (the stationary subframe) so that the relative orientation of the digging chain and housing is fixed, the peat handling means and the digging chain both being driven from the stationary subframe by means of a drive transmission arrangement, characterized in that the drive sprocket of the digging chain is coaxial with and rigidly connected to the peat handling means, and in that the transmission arrangement comprises a single drive transmission connecting the stationary subframe to both the drive sprocket of the digging chain and the peat handling means.

The invention also provides apparatus of the type described in which means are provided on the trajectory of peat cut by the digging device, which means, in operation of the apparatus, serves to define a moving surface, such that cut peat impinging against the moving surface falls within the housing.

The invention also provides a peat extrusion press of the kind described in which a plurality of relatively small exit apertures are provided through each of which peat may be simultaneously extruded, and a cutting member is provided attached to the auger mechanism so as to rotate therewith, thereby macerating the peat within the housing so as to prevent the relatively small apertures becoming clogged.

The invention will now be described in more detail by way of example with reference to the accompanying drawings. In the drawings: Figure 1 is a rear view showing the apparatus mounted on an agricultural tractor with the digging device, in the form of an endless chain, shown in the operational position, inserted in the bog; Figures 2a, 2b and 2c show front, side and plan views respectively of the apparatus, with the digging chain shown in the transport position; Figure 3 is a perspective view of part of the apparatus, illustrating the stationary and movable support subframes; Figure 4 is a perspective view of part of the apparatus illustrating the common drive transmission for the digging chain and the extrusion press auger mechanism, the drive transmission being in the form of a chain and sprocket arrangement;; Figure 5 is an exploded perspective view of part of the apparatus, illustrating the arrangement for bringing cut peat to the extrusion press housing, the arrangement comprising a roller which defines a moving surface, and a canopy; Figure 6 is an exploded perspective view of part of the apparatus, illustrating the extrusion press and the rotating knife, for macerating the peat; and Figures 7 and 7a are side and plan views respectively of a slicing mechanism, for slicing the continuous extrusions into sods.

Referring to the drawings, the apparatus comprises generally; (1) a support frame consisting of (a) a stationary subframe generally designated by the numeral 101 and by means of which the support frame may be mounted upon an agricultural tractor 102 and (b) a movable subframe generally designated by the numeral 103 and pivotally mounted upon the stationary subframe 101; (2) a digging chain 104 mounted upon the movable subframe 103; (3) an extrusion press generally designated by the numeral 105 and extending from the movable subframe 103; (4) a canopy 106 (omitted from all the Figures, except Figure 5) and roller 107 for delivering cut peat from the digging chain 104 to the extrusion press 105; (5) a macerating mechanism within the extrusion press 105, consisting of a rotating knife 108;; (6) a drive transmission for driving the digging chain 104, extrusion press 105, roller 107 and macerating mechanism from the tractor power take off shaft; and (7) a slicing mechanism, for slicing the continuous extrusions into sods.

The stationary subframe 101 (see particularly Figure 3) includes brackets 120, 121, 122 by means of which the stationary subframe 101 may be connected to the three point linkage of tractor 102. The upper linkage 123 (see Figure 1) of the tractor 102 is connected to bracket 120 and the lower linkages i.e. the draught arm (not shown) of the tractor 102 are connected to brackets 121, 122. Bracket 121 has located towards its lower end mounting apertures 121a whereas bracket 1 22 has located towards its upper end mounting apertures 122a.Thus, when mounted upon the three point linkage of the tractor 102, the support frame is disposed at an angle to the horizontal, so that the digging chain 104 is disposed at an angle to the vertical plane through the line of travel of the tractor 102, enabling angled grooves to be made, as shown in Figure 1.

The stationary subframe 101 includes bearing supports 1 30 for a transverse drive shaft 1 31 which is driven, via a T-gear mechanism located in gear box 132, from the tractor power take off shaft 137 (see Figure 2b). Supported on bearings 133 on the transverse drive shaft 131 is a pair of brackets 134 for receiving and supporting a pair of arms 135 integral with and forming part of the movable subframe 103, and by means of which the movable subframe 103 is pivotable relative to the stationary subframe 101 about the axis defined by transverse drive shaft 131. The pivotal movement, shown by arrow A in Figure 3, is accomplished by hydraulic ram 136, connected to the tractor hydraulic system so as to be operable from the tractor cabin. It is not necessary to use the tractor hydraulic lift at any stage. The ram 136 is provided with a pressure relief valve (not shown) to enable the digging chain 104 to deflect automaticaliy from the operational position if it encounters an obstacle.

The movable subframe 103 supports both the digging chain 104 and the extrusion press 1 05.

The extrusion press 105 extends laterally from one side of the stationary subframe 101, and the digging chain 104 extends rearwardly from the movable subframe 103, so that, when the movable subframe 103 is pivotally moved relative to the stationary subframe 101 , the free end of the digging chain 104 is lowered arcuately toward the bog and, when operating, cuts into the bog to adopt a position in which the digging chain 104 is located at an angle to the vertical plane through the line of travel of the tractor. The angle to the vertical plane transverse to the line of travel of the tractor may be varied by varying the amount by which the movable subframe 103 is pivoted relative to the stationary subframe 101, by means of hydraulic ram 136.

The digging chain 104 (best seen in Figure 2b) comprises an elongate endless toothed chain, mounted on a chain guide 140 and sprockets 141, 142. The chain guide is formed from a chain guide section 1 40a and a member 1 40b of the movable subframe 103. Section 140a and member 140b are bolted together by bolts 143. The sprockets comprise a drive sprocket 141 and an idler sprocket 142. The digging chain 104 has cutting teeth 145 in the form of circular discs on the links, disposed at an angle of about 45 to the length of the digging chain 104. The digging chain 104 may be tensioned by means of adjusting screw 146, accessible through aperture 147, in the chain guide section 140a.Chain guide section 140a, which penetrates the bog, may be detached and replaced, when it becomes worn, by slackening digging chain 104 and then removing bolts 143.

The extrusion press 105 (best seen in Figures 2a and 2c) comprise a transversely mounted cylindrical housing 150. An entry aperture 151 is provided at the end of the housing 1 50 adjacent the digging chain 104, through which entry aperture 1 51, the clods 8 of peat enter the housing 1 50. An auger mechanism 1 52 in the housing 1 50 drives the peat towards the other end of the housing 1 50, where it is extruded through three exit pipes 1 53 of relatively small cross sectional areas.

The drive transmission will now be explained in more detail, with particular reference to Figure 4.

The drive from the transverse drive shaft 1 31 is transmitted to the auger drive shaft 1 60 via sprockets 161,162 on shafts 131,160 respectively, and connecting primary drive chain 163. The digging chain drive sprocket 141 and the auger mechanism 1 52 are both fixedly mounted on the auger drive shaft 1 31 and rotate when the auger drive shaft 131 is driven. The auger drive shaft 1 60 also drives the roller 107 and the rotating knife 108, as will be explained in more detail below.

The tension of primary drive chain 1 63 may be adjusted by varying the position of tensioning sprocket 1 64 (see Figure 2b). The auger drive shaft 1 60 is in two parts, connected by a spline joint 1 65 (see Figure 6) which serves to absorb vibration of auger drive shaft160, thereby lengthening its working life.

The peat delivery arrangement will now be described with particular reference to Figures 1 and 5. As mentioned, the clods of peat hurled into the air enter an aperture 151 in housing 150. A roller 107 mounted above the aperture 151,on the trajectory of the cut peat, rolls in the direction shown by the arrow B, so as to direct into the aperture 151 any clods which do not enter aperture 1 51 directly. Because the roller 107 presents a moving surface, the clods do not stick.

The roller 107 is mounted on roller shaft 170 which isjournalled (see Figure 5) in brackets 171, 172 on the housing 130, and the movable subframe 103, respectively. The roller 107 is driven from the auger drive shaft 1 60 by a secondary drive transmission comprising a drive sprocket 173 on the auger drive shaft 1 60, a driven sprocket 1 74 on the roller shaft 170, and a secondary drive chain 1 75 connecting sprockets 173, 174. A housing 176 (shown only in Figure 5) is provided for the secondary drive transmission. A canopy 107 (shown only in Figure 5) covers the roller 107, the aperture 1 51 and the top of the digging chain 104.The provision of the roller 107 coupled with the angle of the digging chain 104 in the bog provides an efficient delivery arrangement, as may be appreciated by referring to Figure 1. The angle of the digging chain gives the clods of cut peat a sideways component towards the aperture 151 and roller 107. The sideways component is maintained when the cut peat falls upon the roller 107.

A macerating mechanism is provided in the extrusion press 1 05. It is desirable that the extrusions be of relatively small cross-section to facilitate drying. As previously mentioned, because of the subsequent closing over of the groove formed in the bog, production is enhanced.

The apparatus of the invention is therefore provided with three extrusion apertures (instead of the single extrusion aperture shown in the prior art), the three apertures allowing a reduced cross section while at the same time enhancing production. The macerating mechanism is provided to prevent the relatively smaller extrusion apertures from clogging.

The macerating mechanism will now be described with particular reference to Figure 6.

The macerating mechanism comprises a first shear plate 180, a second shear plate 1 81, a spacer 1 82 between the shear plates and a rotating macerating knife 108, all mounted towards the end of the auger drive shaft 1 60 so as to rotate therewith, the rotating macerating knife 108 being located in the space between the two shear plates 180 and 181. Peat reaching the end of the housing 1 50 passes through the three large circular apertures 1 80a in shear plate 1 80 and on through the corresponding apertures 181 a in shear plate 181. When passing through the space between the shear plates the peat is cut by the rotating macerating knife 108. The cut peat passes through corresponding apertures 1 84a in end plate 1 84 and passes through extrusion pipes 1 53 to fall on the ground in the form of three parallel lines of peat. Shear plates 180, 181, spacer 182 and end plate 184 are bolted to flange 1 85 on the end of the housing 1 50. The auger drive shaft 160 is provided with a square end 1 86 on which the macerating knife 108 is located, and is journalled on a brass bushing 1 87 in the end plate 184. Should clogging occur in spite of the macerating mechanism, access may be had to the interior of the housing via hatch 1 88 (see Figures 1, 2a and 2c). As will be appreciated, the drive transmission of the invention, which drives the digging chain 104 and the auger mechanism 152, also drives the macerating knife 108.

The extruded peat falls on the ground in t.1e form of three parallel lines of peat. These lines are then sliced into sods by a slicing mechanism. The slicing mechanism will now be described with particular reference to Figures 7 and 7a which show, respectively, a side elevation view of the slicing mechanism, as seen looking towards the end of housing 150, and a plan view of the slicing mechanism. Arrows C, C1 indicate the direction of motion of the tractor 1.

This slicing mechanism comprises a hollow drum 191 pivotally connected by arms 192 to a pivot pin 193 extending from the end of the housing 1 50. The drum 191 is provided with four blades 194 in the form of cleats. The drum 191 is freely rotatable about its longitudinal axis; the emerging lines 195 of peat push the downwardly hanging blade which they encounter ahead of them, causing the drum 191 to revolve and the second blade to swing around behind the first blade, thereby slicing each of the three rows. Thus, three parallel lines of sods lie on the ground behind the tractor 1.

The apparatus produces cylindrical sods which have been found to dry more quickly than conventional rectangular sods.

The length of the sods is determined by, inter alia, the separation of the blades 194 of the slicing mechanism. This separation may be arranged to give any desired length of sod and this feature may be used with advantage to produce sods of somewhat shorter than conventional length which do not have to be broken in two before being inserted in certain stoves, solid fuel burners, and the like.

In the case of larger bogs, apparatus according to the invention, similar to that described above could be made having two or more parallel spaced apart digging chains. For example, a first digging chain could be disposed as shown in the drawings i.e. to one side of the housing, and a second digging chain could project into the housing, as proposed in British Patent Specification No. 764,365 (Ab Hissfabriken). Each digging chain would be driven from the auger drive shaft and a roller would be disposed above each digging chain.

The method of harvesting peat will be apparent from the foregoing description of the apparatus.

Referring particularly to Figure 1, a first groove 201 is made initially. The tractor 1 is then positioned with its left hand rear wheel 202 just above and in line with groove 202. As the tractor 1 moves across the bog, groove 201 is closed as new groove 203 is formed.

Subsequently, groove 203 is closed as groove 204 is formed. Figure 1 shows groove 201 already closed, groove 203 being closed, and groove 204 being formed.

Claims (13)

1. A method of harvesting peat in which an elongate digging device is inserted downwardly into a bog and then moved through the bog, thereby forming a long, deep and narrow groove, characterised in that (a) the digging device is inserted at an angle to the vertical plane through the line of travel of the digging device, thereby forming an inclined groove, and in that (b) the inclined groove is subsequently closed by pressing downwardly on the bog surface above the groove so formed.

2. A method according to claim 1 comprising (a) employing apparatus of the type described to make a first inclined groove, and (b) closing said first inclined groove by downward pressure of the prime mover, while forming a second inclined groove.

3. Apparatus of the type described in which first means are provided enabling the digging device to be inserted at an angle to the vertical plane through the line of travel of the digging device, thereby to form an inclined groove, and in that second means are provided to enable the inclined groove to be subsequently closed by pressing downwardly on the bog surface above the groove so formed.

4. Apparatus of the type described in which (a) the peat digging device is an endless toothed digging chain having a drive sprocket at the end adjacent the support frame and in which (b) the housing and digging chain are both fixedly mounted on a first sub-frame (the movable subframe) which is pivotally movable relative to a second subframe (the stationary sub-frame) so that the relative orientation of the digging chain and housing is fixed, the peat handling means and the digging chain both being driven from the stationary subframe by means of a drive transmission arrangement, characterised in that the drive sprocket of the digging chain is co-axial with and rigidly connected to the peat handling means, and in that the transmission arrangement comprises a single drive transmission connecting the stationary subframe to both the drive sprocket of the digging chain and the peat handling means.

5. Apparatus according to claim 4, characterised in that the drive transmission comprises a drive chain and sprockets, the transmission drive sprocket being mounted coaxial with the pivotal axis of-the movable subframe and the transmission driven sprocket being coaxial with and rigidly connected to the peat handling means.

6. Apparatus according to claim 5, for mounting on an Fgricultural tractor, characterised in that a T-gear mechanism is provided, mounted on the stationary subframe, for connecting the tractor power take off shaft to the transmission drive sprocket.

7. Apparatus according to claims 4, 5 or 6 for use in connection with the method of claims 1 or 2 of possessing the features of claim 3.

8. Apparatus of the type described including peat deflection means in the form of a movable surface operable so that cut peat impinges against the moving surface and is thereby deposited into the housing.

9. Apparatus according to claim 8, characterised in that the moving surface is a roller driven from the prime mover.

10. Apparatus according to claim 8 or 9 possessing the features of claims 4, 5, 6 or 7.

11. A peat extrusion press of the kind described in which (a) a plurality of relatively small exit apertures are provided through each of which peat may be simultaneously extruded and (b) a cutting member is provided co-axial with and connected to the auger mechanism so as to rotate therewith, thereby macerating the peat within the press so as to prevent the relatively small apertures becoming clogged.

1 2. A peat extrusion press according to claim 11 in which the rotating cutting member is mounted between two fixed plates each having corresponding apertures, which in turn correspond with the exit apertures of the press.

13. Apparatus according to any of claims 4 to 10 provided with a peat extrusion press according to claims 11 or 12.