GB2144963A

GB2144963A - Improvements in mole drainers

Info

Publication number: GB2144963A
Application number: GB08417516A
Authority: GB
Inventors: John Robert Hall; Robert Baker Orford; Robert Miles Orford
Original assignee: Miles & Son Ltd G
Current assignee: Miles & Son Ltd G
Priority date: 1983-08-17
Filing date: 1984-07-10
Publication date: 1985-03-20
Also published as: GB8417516D0

Abstract

A mole drainer has a mole 26 supported at the bottom of an arm 24. The arm can be moved up and down relative to the beam 10, and can also be pivoted about a horizontal axis on a projection 40. A link 32 controls this horizontal pivoting. In one embodiment, the arm can also be pivoted about a vertical axis although any movement about a vertical axis will be only of a small amount. The arm may be held by bolts designed to shear on overload. <IMAGE>

Description

SPECIFICATION Improvements in mole drainers Field of invention This invention relates to a mole drainer.

Background to the invention A mole drainer comprises a beam having means at its front end by which it can be attached to a tractor and a mole-supporting arm at its rear end. The beam may be pivotally mounted on a framework carrying ground wheels. By means of an hydraulic arm, the beam and framework can be relatively pivoted in order to allow the mole to be pulled into the ground.

At the rear end of the beam, the molesupporting arm is usually adjustable in height, thereby to enable working depth control.

However, the cutting angle of the mole relative to the beam is substantially fixed, and it has been found that this is sometimes disadvantageous.

The invention According to one aspect of the invention, there is provided a mole drainer comprising a beam adapted for attachment to a tractor linkage or the like, a ground wheels supporting framework, means pivotally mounting the beam to the framework, power means for relatively pivoting the beam and framework, an arm adjustably mounted to the rear end of the beam and a mole (with or without expander) carried at the lower end of said arm, wherein the mole-supporting arm is adjustably mounted to the beam by mounting means permitting said arm to be adjusted both in height and in angle in a plane through the arm and the beam.

Thus, in accordance with the invention, not only is the working depth of the mole adjustable, but also its angle of attack can be adjusted.

According to a preferred aspect of the invention, the said mounting means for the mole supporting arm comprises an arm-receiving slot in the beam, means in the slot defining an axis for pivotal movement of the arm, and an adjustable link on the beam which co-operates with the arm to enable pivoting of the latter about said.axis.

The pivot axis is preferably defined by a convexity on one upright edge (preferably the front edge) of the slot in the beam. This may be either a relatively sharp ridge or a rounded bulging of said upright edge.

The link is preferably an apertured link for alignment with any one of a series of holes provided on the mole-supporting arm to enable height adjustment, the height of adjustment being fixed by a pin passed through the aligned aperture and hole. The link can be drivable by a screwthread adjustment device to drive the link longitudinally in the front/ rear or rear/front direction pulling the pin (and thus that point of the mole-supporting arm) with it. The link aperture is preferably a slot giving some freedom of play, a wedge being knocked in (in known manner) to effect absolute locking of the arm in its chosen position cif adjustment (height and angle).

The mole supporting arm may be carried in a beam extension section, and the extension section can be hinged to the beam for movement relative to the beam at least about a horizontal axis, and the hinge movement can be controlled by a rigid link of adjustable length between the extension section and the beam.

The mole supporting arm can slide through the extension section for height and adjustment.

In addition to movement of the extension section about a horizontal axis (which results in movement of the mole-supporting arm in a plane through the arm and the beam), it may be advantageous to give the extension section and the mole-supporting arm some degree of freedom relative to a line joining the point where the mole drainer is attached to a tractor and the mole itself, so that the mole can be moved slightly to one side or the other of this line to correct any tendency to travel along any other than the desired path.

Three rigid links of adjustable length may be connected between the beam and the extension section, one to control hinge movement about a horizontal axis and two, one on either side of the beam, to control hinge movement about a generally vertical axis.

The rigid links can include ratchet mechanisms for effecting adjustment.

The hinge may include a bearing which permits freedom of movement about a primary axis and limited freedom of movement about a second axes orthogonal to the first axis.

The ends of the rigid links may be connected to the beam and the extension section respectively by similar bearings.

Alternatively, the hinge may be a universal joint.

To facilitate towing of the mole drainer when it is not in work, the front end of the beam may be provided with a towing arm which is hinged to the beam and is restrained by a restraining arm also hinged to the beam.

The restraining arm can be disengaged from the towing arm when the mole drainer is in work.

Since the mole supporting arm is secured to the beam through the adjustable mounting means, readily shearable connection is preferably provided between at least one end of each said mounting means and the point of attachment between the mounting means and he beam or the arm or a beam extension containing the arm. In this way any impact between the mole or the arm and a rock or large embedded stone or the like will not be transmitted to the beam in such a way as to potentially break or damage the arm or the beam but instead the shearable connection will break allowing the mole and arm to swing rearwardly and upwardly.

Brief description of the drawings.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view of a first embodiment of mole drainer in accordance with the invention; Figure 2 is a side view of a second embodiment of mole drainer in accordance with the invention; Figure 3 is a detailed side view of the joint between the beam and an extend ion section of the beam from the embodiment of Fig. 2; Figure 4 is a plan view of the joint shown in Fig. 3; Figure 5 shows an alternative form of hinge joint between the beam and the extension section; and Figure 6 is a detailed perspective view of the front end of the mole drainer shown in Fig. 2.

Description of preferred embodiments.

In Fig. 1, the reference 10 denotes a beam which at its front end (not shown) is adapted for attachment to a tractor linkage in a conventional manner. A framework 1 2 carrying ground wheels 14 is privotally connected to the beam at 16.

At its rear end, the beam 10, which is in the form of a pair of slightly spaced apart beam bars, has bolted between its bars front and rear plates 18, 20 which define between them a slot-like space 22 through which can be inserted a mole-supporting arm 24 in the form of a thin, elongate plate. At its lower end the arm fixedly carries a mole cutter 26 with an associated trailing expander 28.

Any one of a series of holes 30 along the length of the arm 24 can co-operate with an apertured link 32, thereby to enable the working depth of the mole to be adjusted, the height of adjustment being fixed by a pin 34 passed through the aligned hole and apertures.

A hydraulic ram 36 is shown in an extended condition in which, by virtue of the relative positions of beam 10 and framework 12, the mole 26 is held clear of the ground.

However, when the ram 36 is retracted, the mole 26 will be lowered to the ground to commence cutting a drainage channel, the desired working depth being reached when the ram has fully retracted. The ram is extended to lift the mole as cutting of the drainage channel is completed.

Reference 38 denotes a soil breaker for loosening the ground in advance of arrival of the mole.

Hitherto, the orientation of the mole relative to the beam has been substantially fixed. It has been found in practice, however, that it is advantageous to allow adjustment of the angle of attack of the mole.

To this end the link 32 is adjustably mounted for movement in its longitudinal direction along the length of the beam, thereby via the coupling pin 34 to drive the connected point of the mole-supporting arm 24 forwardly or rearwardly, causing said arm 24 to pivot about a ridge or convexity 40 provided on the rear edge of the plate 18, ie on the front edge of the slot-like space 22, which is suitably over-sized relative to the width of the arm 24 to enable such pivotal adjustment to take place.

Adjustment of the link 32, which is an Hshaped member receiving the arm 24 between its limbs at the rear end, is by means of a screwthreaded bolt 42 bearing two nuts 44 (one being a locking nut) and which at its rear end has an apertured head 46 engaging between the limbs of the link 32 at the front end of the latter. A coupling pin conveniently having a quick-release handle 48, enables assembly by srewing the pin through aligned holes in the limbs of the link and the bolthead between them, one side of the link carrying an integral nut.

A similar device may be used to enable coupling pin 34 to be screwed into position to secure the rear end of the link to the molesupporting arm. Preferably, however, at the rear end of the link, it is provided with a slot 50 to receive the coupling pin 30, thus affording a degree of free play. In accordance with conventional practice, a wedge 52 is driven into the rear side of the slot-like space 22 positively to lock the mole in its final position of adjustment in respect of both height and angle.

In the mole drainer shown in Fig. 1, the angle of attack of the mole is adjustable to suitable various types of ground and various soil conditions, independently of the conventionally provided working depth adjustment.

The mole drainer shown in Figs. 2 to 6 permits further degrees of adjustment.

In Figs. 2 to 6, reference numerals already used in Fig. 1 are repeated for components which are generally the same as components already described in connection with Fig. 1.

In Fig. 2, the mole-supporting arm 24 is mounted in a beam extension section 60 which is hinged to the beam 10 at 62. The mole-supporting arm 24 can be moved up and down through the extension section 60, making use of holes 30 to secure the arm in any desired position.

The hinge joint 62 comprises a lug 64 on the beam 10 and a yoke 66 on the extension sectio 60. A bearing 68 is fitted between these interchanging parts. This bearing has a primary, horizontal axis and thus the extension section 60 can move up and down relative to the beam 10. This movement is limited by a rigid link 70 connected between the extension section 60 and the beam 10.

This link 70 includes a ratchet-operated turn buckle which can be turned in one direction to shorten the link or in the other direction to extend the link.

Besides the primary axis of the bearing 68, a limited degree of movement is provided for about secondary axes which are generally at right angles to the primary axis. This is made possible by a barrel-shaped outer circumference of the bearing 68, and by a degree of clearance between the lug 64 and the arms of the yoke 66. This movement is controlled by two links 72 and 74 which are similar in nature to the link 70 already described, it is to be noted that in Fig. 3, the link 74 has been omitted for clarity, and in Fig. 4 the link 70 has been omitted for clarity. These links 70, 72, 74 end in yokes which are attached to lugs 76 using bearings of the same type as the bearing 68 which has just been described.

Two links 72 and 74 are used to control movement about the secondary axes, because the forces imposed between the extension section 60 and the beam 10 will be particularly severe if it is necessary to angle the mole to the direction of travel of the drainer.

In place of the barrel-bearing 68 used between the extension section 60 and the beam 10, a conventional universal joint may be used. A typical form of such a joint is shown in Fig. 5 where separate horizontal and vertical pivot axis are provided connected by a connecting piece 78.

Fig. 6 shows an arrangement at the front end of the beam 10. A towing arm 80 has a towing eye 82 at the front. The arm 80 is hinged to the beam 10 at 84. Freedom of movement about this axis 84 is necessary whilst the mole draine is in work, to allow the beam 10 to alter its orientation relative to the tractor both whilst the mole is being sunk in the ground and whilst the tractor is travelling over uneven ground.

However, when the mole drainer is being towed on its ground wheels 14, it is desirable to limit movement of the towing arm about the axis 84. To accomplish this, a restraining arm 86 is hinged to the beam 10 at 90 and has a yoke 92 which fits over the towing arm 80. At the bottom of the yoke 92, the free ends of the yoke are joined by a bolt 94 so that the socket is formed in which the arm 80 can slide. An adjustable button at 96 is fitted on the towing arm 80 and this limits the extent to which the arm 80 can be raised about the axis 84, when the abutment 96 comes into contact with the yoke 92. This abutment can however, be moved by loosening the bolts which hold it against the -arm 80 so that it can be repositioned where required.

The towing arm is prevented from dropping too far relative to the beam 10 when the restraining arm 86 comes into contact with the end of the beam.

To disable the restraining arm 86, the bolt 94 is removed and the arm 86 is swung out of position.

The provision of the considerable degree of relative movement possible between the extension section 60 and the beam 10 makes "fine tuning" of the mole position relative to the line of the beam and relative to the direction of towing quite possible. This can help to increase the accuracy of positioning of the mole drain being formed and can also help to reduce the load on the tractor, since the mole can always be very accurately lined up.

Although not shown the belts which secure in place the plate 20, in Fig. 1, are designed to shear when a force is exerted by the mole supporting arm 24 which is greater than a design threshold. This latter is selected as being equal to the force exerted by the arm 24 upon the impact by the arm or the mole 26 with an immovable rock or the like whilst the beam 1 0- is advancing at normal moling speed in a forwarding direction. By incorporating such shearable devices as the means for securing the plate 20 in place, so the overall implement will be saved from serious damage in the event of the mole or arm 24 impacting a large rock or stone in the sub-soil.

In the same way although not shown, a shearable connection may be provided between a lug 76 and an end of the adjustable link 70 and likewise between the lugs 76 dashed and 76 double dashed and the ends of their respective adjustable links 72 and 74.

Typically the shearable connection is a shear pin located through the lug 76 at the lower end of the adjustable link 70 and at the forward end of the adjustable links 72 and 74 where these are provided.

Further, although not shown in detail, it is to be understood that the three adjustable links shown in Figs. 2, 3 and 4 are not essential and-a single adjustable link 70 mounted above the beam would in practice suffice.

Claims

1. A mole drainer comprising a beam adapted for attachment to a tractor linkage or the like, ground wheels supporting framework, means pivotally mounting the beam to the framework, power means for relatively pivoting the beam and framework, an arm adjustably mounted to the rear end of the beam and a mole carried at the lower end of said arm, wherein the mole supporting arm is adjustably mounted to the beam by mounting means permitting said arm to be adjusted both in height and in angle in a palne through the arm and the beam.

2. A mole drainer as claimed in Claim 1, wherein the mounting means for the mole supporting arm comprises an arm-receiving slot in the beam, means in the slot defining an axis for pivotal movement of the arm, and an adjustable link on the beam which cooperates with the arm to enable pivoting of the latter about said axis.

3. A mole drainer as claimed in Claim 2, wherein the pivot axis is defined by a convexity on one upright edge of the slot in the beam.

4. A mole drainer as claimed in Claim 2 or Claim 3, wherein the link is an apertured link for alignment with any one of a series of holes on the mole supporting arm, and wherein a pin is provided to be passed through the apertures in the link and one of the holes to fix the height of the mole supporting arm.

5. A mole drainer as claimed in any one of Claims 2 to 4 wherein a screwthread adjustment device is provided to drive the link forwards or backwards to tilt the mole supporting arm.

6. A mole drainer as claimed in Claim 4, wherein the link apertures are elongate slots.

7. A mole drainer as claimed in Claim 1, wherein the mole supporting arm is carried in a beam extension section, and the extension section is hinged to the beam for movement relative to the beam at least about a horizontal axis, and wherein the hinge movement is controlled by a rigid link of adjustable length between the extension section and the beam.

8. A mole drainer as claimed in Claim 7, wherein the mole supporting arm can slide through the extension section for height adjustment.

9. A mole drainer as claimed in Claim 7 or Claim 8, wherein the extension section is able to move relative to the beam about a generally vertical axis.

10. A mole drainer as claimed in Claim 9, wherein three rigid linkages of adjustable length are connected between the beam and the extension section, one to control hinge movement about a horizontal axis and two, one on either side of the axis, to control hinge movement about a generally vertical axis.

1 3. A mole drainer as claimed in any one of Claims 7 to 1 2 wherein the ends of the or each rigid linkage or linkages of adjustable length is or are attached to the beam and the extension section respectively by bearings as set out in Claim 12.

1 5. A mole drainer as claimed in any preceding claim, wherein a towing arm is hinged to the front end of the beam, a restraining arm is also hinged to the beam at a position behind the hinge axis of the towing arm and the restraining arm can engage the towing arm to limit pivoting movement of the towing arm relative to the beam.

1 9. A mole drainer as claimed in Claim 7 wherein the rigid linkage of adjustable length is attached through a shearable connection such as a shear pin either to the beam extension section or to the beam itself.

10. A mole drainer as claimed in Claim 9, wherein three rigid links of adjustable length are connected between the beam and the extension section, one to control hinge movement about a horizontal axis and two, one on either side of the axis, to control hinge movement about a generally vertical axis.

11. A mole drainer as claimed in Claim 7 or Claim 10, wherein the rigid links of adjustable length include ratchet mechanisms for effecting adjustment.

1 2. A mole drainer as claimed in any one of Claims 7 to 11 wherein the hinge includes a bearing which permits freedom of movement about a primary axis, and limited freedom of movement about second axes orthogonal to the first axis.

1 3. A mole drainer as claimed in any one of Claims 7 to 1 2 wherein the ends of the or each rigid link or links of adjustable length is or are attached to the beam and the extension section respectively by bearings as set out in Claim 12.

1 4. A mole drainer as claimed in any one of Claims 7 to 11, wherein the hinge is a universal joint.

1 5. A mole drainer as claimed in any preceding claim, wherein a towing arm is hinged to the front end of the beam, a restraining arm is also hinged to the beam at a position behind the hinge axis the towing arm and the restraining arm can engage the towing arm to limit pivoting movement of the towing arm relative to the beam.

16. A mole drainer as claimed in Claim 15, wherein the towing arm includes an adjustable abutment which abuts the restraining arm to limit pivoting movement of the towing arm relative to the beam.

1 7. A mole drainer as claimed in Claim 1 5 or Claim 16, wherein the restraining arm can be disengaged from the towing arm.

18. A mole drainer as claimed in Claim 2 wherein the rear wall defining the arm receiving slot in the beam is securable in position by a shearable connection which is designed to shear in the event of an impact load on the arm or the mole equal to or greater than that which would be experienced by the arm or the mole hitting an immovable object when travelling in a forward direction at normal moling speed.

1 9. A mole drainer as claimed in Claim 7 wherein the rigid link of adjustable length is attached through a shearable connection such as a shear pin either to the beam extension section or to the beam itself.

20. A mole drainer substantially as herein described with reference to either Fig. 1 or Figs. 2 to 6 of the accompanying drawings.

1. A mole drainer comprising a beam adapted for attachment to a tractor linkage or the like, ground wheels supporting framework, means pivotally mounting the beam to the framework, power means for relatively pivoting the beam and framework, an arm carried at the rear end of the beam, a mole carried at the lower end of said arm, means enabling height adjustment of the arm relative to the beam, means defining a horizontal pivot permitting the arm to be be adjusted in angle in a plane through the arm and the beam, and a rigid linkage of adjustable length for controlling the angular adjustment of the arm.

2. A mole drainer as claimed in Claim 1, wherein mounting means for the mole supporting arm comprises an arm-receiving slot in the beam and means in the slot defining an axis for the pivotal movement of the arm, the rigid linkage connecting between the arm and the beam.

4. A mole drainer as claimed in Claim 2 or Claim 3, wherein the adjustable linkage in cludes an apertured link for alignment with any one of a series of holes on the mole supporting arm, and wherein a pin is provided to be passed through the apertures in the link and one of the holes to fix the height of the mole supporting arm.

5. A mole drainer as claimed in Claim 4 wherein the adjustable linkage includes a screwthread adjustment device provided to drive the apertured link forwards or backwards to tilt the mole supporting arm.

6. A mole drainer as claimed in Claim 4 or Claim 5, wherein the linkage apertures are elongate slots.

7. A mole drainer as claimed in Claim 1, wherein the mole supporting arm is carried for height adjustment in a beam extension section, and wherein the extension section is hinged to the beam for movement relative to the beam about a horizontal axis defining said horizontal pivot, and wherein the rigid linkage of adjustable length is connected between the extension section and the beam.