US3670431A

US3670431A - Mole plough depth control mechanism

Info

Publication number: US3670431A
Application number: US75720A
Authority: US
Inventors: Ainsley Neville Ede
Original assignee: HUDSWELL YATES DEV Ltd
Current assignee: HUDSWELL YATES DEV Ltd
Priority date: 1967-03-10
Filing date: 1970-09-25
Publication date: 1972-06-20
Anticipated expiration: 1989-06-20
Also published as: GB1187144A; DE1708565B2; DE1708565A1; FR1556124A; NL6803344A; DE1708565C3

Abstract

A mole plough having a plough blade rigidly secured to a support pivotally connected to a tracked carriage about a transverse horizontal axis, the blade having a rigid forward portion and a trailing foot portion pivotally connected thereto and means for tilting the foot portion relative to the remainder of the blade whereby the alteration of the angle of the undersurface of the foot portion and the reaction of the foot portion against the ground below the blade effects a change in the operating depth of the blade.

Description

United States Patent Ede [451 June 20, 1972 [541 MOLE PLOUGH DEPTH CONTROL [561 References i d MECHANISM UNITED STATES PATENTS [72] Inventor: Ainsley Neville Ede, Cambridge, England 25,902 10/1859 Jones ..37/ 193 [73] Assignee: Hudswell Yates Developments Limited, Leeds Ymkshlre, 26,355 12/1859 Hinckley. [22] Filed: Sept. 25, 1970 2,715,286 8/1955 Saveson ..37/193 [21] APPL 75 720 Primary Examiner-Robert E. Pulfrey Assistant ExaminerCliff0rd D. Crowder Related U.S. Application Data Attarneylmirie & Smiley [63] Continrfitiojn-in-part of Ser. No. 715,469, March 8, [57] ABSTRACT 1968 a an oned' A mole plough having a plough blade rigidly secured to a support pivotally connected to a tracked carriage about a trans- [30] Foreign Apphcanon Pnonty Data verse horizontal axis, the blade having a rigid forward portion March 10, 1967 Great Britain ..11,287/67 and a trailing foot portion pivotally connected thereto and means for tilting the foot portion relative to the remainder of [52] U.S. Cl ..37/l93, 172/699, 172/736 the blade whereby the alteration of the angle of the undersur- [5 1] face of the foot portion and the reaction of the foot portion [58] against the ground below the blade effects a change in the operating depth of the blade.

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SHEET 20F 2 MOLE PLOUGI'I DEPTH CONTROL MECHANISM This application is a continuation in -part of application Ser. No. 715,469 filed March 8, 1968, now abandoned.

The invention relates to apparatus for use in pipelaying and similar operations, and particularly to mole plough apparatus incorporating a member-which is supported at least partially below ground in use, the member being hauled along as by a tractor or winch whereby it produces a below-ground passage or tunnel.

The invention is particularly concerned with means for adjusting the depth below ground of the passage or tunnel.

According to the invention, there is provided mole plough apparatus, comprising a support, a mole plough element rigidly attached to said support, means for applying a force to said support whereby to drag said mole plough element through the ground to produce a passage through the ground at a desired working depth, said mole plough element having a forward portion rigid with said support and a trailing foot member hinged to said forward portion about a horizontal axis transverse to the direction of movement of the mole plough element in use, the lower surface of said trailing foot member constituting part of the under surface of the mole plough element, and power means coupled to said foot member and operable to tilt same relative to the remainder of the mole plough element, whereby to alter the angle of the under surface of the mole plough element relative to the horizontal and thereby, through ground reaction, to tend to alter the working depth of the mole plough element.

Mole plough apparatus embodying the invention will now be described by way of example only with reference to the accompanying drawings in which:

FIG. 1 is a diagrammatic side elevation of one form of apparatus;

FIG. 2 is a cross-section on the line 2-2 of FIG. 1;

FIG. 3 is a diagrammatic side elevation of a further form of apparatus;

FIG. 4 is a cross-section on'the line 44 of FIG. 3; and

FIG. 5 is a diagrammatic side elevation showing a modification of the apparatus of FIGS. 1 and 2.

In all the Figures, the ground level is indicated by the line A.

Referring to FIGS. 1 and 2, a mole plough blade is rigidly attached to a beam 1 1 and has a forward portion rigid with the beam and a trailing foot which is wedge-shaped and is pivoted about a transverse horizontal axis 21 near the point of the blade, the rear of the foot being movable up and down through a range of a few inches by means of a stiff rod 22 actuated by a vertically placed hydraulic ram 23 above ground level. As shown in FIG. 2, the cross section of the foot of the blade is more or less rectangular, which is required to give the necessary soil surface area and to exclude dirt from entering between the foot and the blade. An expander 10b, to increase the cross-section of the bottom of the passage cut through the soil, is carried at the rear of the foot of the blade 10 and is substantially circular in crosssection and of diameter greater than the width of the foot.

In use, the end of the beam 11 opposite to the blade 10 is pivotally supported on a tracked carriage (not shown) which is hauled along the ground so that the blade 10 cuts a slit trench through the ground. When the angle of incidence of the foot 20 is altered by tilting about axis 21, the effect is for the blade to move along the new line made by the foot. Thus, if the blade is below the required depth, the rear of the foot is moved downwards causing the blade to rise, or vice versa. The tilting foot portion may be of enlarged width relative to the remainder of the blade. It should be noted that the upper surface of the blade is not materially important in regulating grade or depth as, although the forces on it are heavy, the changes in force accompanying changes in angle are light in comparison with the lower surfaces which are working against undisturbed soil. Moreover in each working position the blade seeks a position in which its lower surface is generally parallel with the line of pull and the blade continues to operate at this depth until further adjustment of the foot 20 is effected.

The apparatus of FIGS. 3 and 4 has a cylindrical mole plough element 24 rigidly attached to the foot of the blade 10. An actuating ram 25 is placed horizontally within the nose of the mole 24, and controls the horizontal shifting of a pad or roller 26 at the rear of the mole. The pad or roller 26 controls the separation between the inclined upper surface 27 of a mole foot 28 and another surface 29 formed inside the roof of the rear of the mole, the foot 28 being pivoted to the rest of the mole about a transverse horizontal axis 28a. As in the case of the V-blade 10 of FIGS. 1 and 2, a more or less rectangular cross section is required for the base. The ram 25 is controlled through hydraulic pipe lines 25a and and controls the depth of the element by adjusting the angle of the foot 28 as in the arrangement of FIGS. 1 and 2.

The utilization of these systems of grade control enable the desirably sluggish reactions of the blade or mole to variations in elevation of the carriage to be combined with sufficiently quick reaction to depth control signals as received from an automatic system. It will be noted that depth changes are effected by alterations in ground reaction brought about by application of a vertical force to the trailing end of the pivoted foot portion. This indirect technique enables sufficient force to be applied to overcome the high resistance present, the latter being such that a direct pivotal movement of the leading edge of the blade or bodily lifting of the blade are impractical.

FIG. 5 illustrates a modification applicable to any of the arrangements illustrated in the other Figures though it is shown as applied particularly to the arrangements of FIGS. 1 and 2. A hydraulic ram 30 is provided for raising the beam 11 and blade 10 clear of the ground for transport purposes, and is arranged in addition to apply constant regulatable vertical pressure to the beam assembly when the plough is in use, though there is no vertical constraint on the beam. This enables additional downward force to be applied to the blade 10 when the blade is operating at extreme depth and the vertical component of force of the blade is barely sufficient to hold it down. The reverse is the case when operating in very soft soils such as peat, when the force due to the weight of the beam and blade predominates, and a controlled upward force can be ap plied by the ram 30 in order to leave a distinct but small residual force to be borne by the foot of the blade 10 for grading purposes in the manner described in connection with the other Figures. The ram 30 is actuated hydraulically from a feed and pressure control system 31 leading to a selector valve 32 having

connections

33, 34 with opposite ends of the ram cylinder 35.

As explained above, the tracked carriage, to which the beams 11 of the arrangements illustrated are pivotally attached, is winch-hauled and does not rely upon its tracks for gripping the ground; a further feature when additional bearing surface is required in soft ground is the provision of a plate lowered under driver control by four hydraulic rams. The plate, with turned-up ends to assist in riding over the soil, lowers to a position occupying the space between, and level with, the lower surface of the tracks; alternatively the plate could occupy a fixed position.

Various other modifications may be made without departing from the invention. For example, the trailing foot portion could be pivoted at any suitable point along the lower edge of the blade and could constitute the forward portion of the lower edge of the blade, the rearward portion being rigid with the blade. In all cases the foot forms at least a part of the lower edge of the blade and the leading edge of the blade is rigid with the blade proper and is not subjected to any angular or bodily movement except such as is derived from angular movement of the foot. Moreover, while in the drawings the lower edges of the blade and of the foot are coplanar in their mean positions, they could alternatively be inclined to one another, that is the lower edge of the foot portion could be inclined upwardly or downwardly relative to the lower edge of the blade proper.

I claim:

1. Mole plough apparatus, comprising a support, a mole plough element rigidly attached to said support, means for applying a force to said support whereby to drag said mole plough element through the ground to produce a passage through the ground at a desired working depth, said mole plough element having forward and upper portions rigid with said support and a trailing foot member hinged behind said forward portion and below said upper portion about a horizontal axis transverse to the direction of movement of the mole plough element in use, said trailing foot member having a lower surface constituting part of the under surface of the mole plough element, and power means coupled to said foot member and operable to tilt same relative to the remainder of the mole plough element, whereby to alter the angle of the under surface of the mole plough element relative to the horizontal and thereby, through ground reaction, to tend to alter the working depth of the mole plough element.

2. Apparatus according to claim 1 including an expander member attached to the rear edge of said foot member, the expander member having a substantially circular cross-section with its diameter parallel to, and greater in length than, the width of said foot member.

3. Apparatus according to claim 1, wherein said mole plough element comprises a blade, said power means comprising a piston-cylinder assembly including a piston rod enclosed within said blade and connected to said foot member for swinging the foot member about said transverse horizontal axis.

4. Apparatus according to claim 1, wherein said foot member is enlarged in width relative to the remainder of said mole plough element.

5. Apparatus according to claim 1, wherein said support comprises an elongated beam pivotally connected to a forward portion of the apparatus, and including force-applying means connected to the beam and operative to apply a vertical force thereto.

6. Apparatus according to claim 1, wherein said mole plough element includes an upper blade member and a lower substantially cylindrically shaped mole assembly, said mole assembly comprising an upper portion rigid with the lower end of said blade member, said foot member being hinged to said upper portion about said transverse horizontal axis, and said upper portion overlapping said foot member.

7. Apparatus according to claim 6, wherein said power means includes actuating means disposed within said upper portion and operative to pivot said lower portion about said axis, said actuating means comprising a ram engaging and movable between facing mutually inclined surfaces respectively attached to said upper and lower portions.