GB2029182A - Ditchless drainlayer - Google Patents

Abstract

The drainlayer comprises a frame 2 mounting a cutter 1 for laying drainpipes, provided with a hydraulic unit 3 for changing its angular position, controlled by a transmitter 4 via an amplifier-converter 5, and a device for controlling the height of the cutter made as a support connected to the cutter 1 and swivelling around a horizontal transverse axis, with a hydraulic unit 12 for turning the support. The unit 12 is controlled via an additional amplifier-converter 7 by a transmitter 6 for the height of the cutter 1. The support comprises blades 8 diverging sideways from the cutter 1, the blades 8 being rigidly attached to a link 11 which is articulated to the cutter by two rods 9, 10 arranged one above the other, whose extensions converge in front. <IMAGE>

Description

SPECIFICATION Ditchless drainlayer The present invention relates to machines for laying drainpipes and lines by the ditchless method.

Ditchless drain layers can be employed predominantly for constructing drainage systems in drainage and irrigation zones. They can also prove useful for laying flexible pipelines or cables into the ground, particularly when it is required to ensure a predetermined depth or gradient, or both.

The present invention provides a ditch less drainlayer comprising a frame with a drainlaying working element secured to said frame and provided with a hydraulic cylinder for changing its angular position and an angular-position transmitter with an amplifier-converter, and a device for controlling the height of the working element in the form of a support connected to said working element and capable of being rotated around a transverse horizontal axis by a hydraulic cylinder wherein, according to the invention, the swivelling support is connected by its turning hydraulic cylinder and an additional amplifier-converter with a transmitter installed on the working element and indicating its position in height, said support being made as blades diverging in both directions from the working element, rigidly connected to a connecting link which is articulated to the working element by two rods arranged one above the other, whose extensions converge in the direction of movement of the machine while the transmitter of the angular position of the working element is connected to its amplifier-converter with the hydraulic cylinder intended to change the angu larposition of the working element.

To enable the cutter to be lifted when the drainlayer is stationary it is practicable for the link to include a swivelling sector provided with a releasable stop, the blades being rigidly secured to the sector.

Moreover, for regulating the distance between the fulcrum of the blades and the fulcrum of the resul- tant force with the aim of adapting the drainlayer for operation under various soil conditions, it is possible to install a slide intended to change the convergence angle of the rods and being articulated to the rear end of the upper rod, a guide for the slide being articulated to the rear end of the lower rod and secured to the link, while the displacement of the slide is ensured by an additional hydraulic piston-andcylinder unit.

The slide guide can be made either rectilinear or arcuate with the centre of arc curvature located in the hinge axis of the front end of the upper rod. The latter arrangement rules out the necessity for additional turning of the blades in the course of regulating the distance between the blade fulcrum and the fulcrum of the resultant force.

The essence of the present invention lies in the following. The ditch less drainlayer according to the invention consists of a cutter-type working element connected by a frame to the prime mover and provided with two automatic control circuits for controlling, respectively, the height and the angular position of the working element. In the first one of these circuits the support for regulating the height of the working element is constituted by blades sticking out on both sides of the cutter-type working element and connected to the latter by two rods arranged one above the other. These articulated rods converge in front of the machine (as it goes) forming a four-bar mechanism whose upper and lower bars are constituted by these rods while the sides are constituted by the cutter-type working element and the connecting link to which the blades are rigidly connected.

The point where the extensions of these rods intersect each other is the instantaneous centre of velocities of the blades when the latter move relative to the cutter-type working element. This point serves as a kind of a hinge around which the blades turn.

Such a layout ensures a considerable distance between the blade fulcrum and the centre of pressure, i.e. the point of application of the controlling lifting force acting on the cutter. The largerthis distance, the higher will be the operating speed of the control system. However, the blades perform not only the plane-parallel motion but also turn somewhat in the process of the control. In the equilibrium position they are set at a certain angle of attack causing a vertical component which counters the tendency of the cutter towards penetration into the ground under the effect of its weight and the shape of the cutter point on which arises a downward directed component of the ground reaction which improves substantially the conditions of control.

The heighttransmitter may be of any known design. The required height and gradientthroughout the length of the drainage line can be set by a tracing cable, laser beam, sighting lines of an optical instrument, etc. The type and construction of the transmitter depend on whichever of these means is selected.

The circuit for angular stabilization of the cutter includes an inclination transmitter of any type (pendulum, liquid, etc.) while changes in the angular position of the cutter are made, according to the invention, by a hydraulic piston-and-cylinder unit, which can be installed between a prime mover and the frame if the cutter is rigid with the frame or between the frame and the cutter if they are connected by an articulated joint. The constancy of the angular position ensures a corresponding constancy of the cutting angle, and guarantees the existence of the back angle, thus eliminating the effect of changes in the height of the prime mover upon the angular position of the cutter.

The simultaneous action of both above-mentioned circuits, i.e. stabilization of the cutter with respect to angle and height, weakens substantially the effect of the disturbing factors which tend to distort the trajectory of the cutter. This ensures actual independence of the laying accuracy and speed on the surface irregularities under the prime mover and on the chance forces applied to the cutter thereby ensuring the laying of drainpipes with a requisite high accuracy.

In the course of laying it may become necessary to raise the cutter out of the drain slit when the prime mover is standing still. This necessity may arise, for example, when encountering an unsurpassable obstacle, (a large boulder, etc.), during operation in cramped conditions, when the drainage line ends close to an artificial structure. The blades dug into the slit walls oppose such a raising. Therefore, the blades can be secured rigidly on the abovementioned rotatable sector. The operator can release the sector at will and the sector will turn through 90" approximately together with the blades as the cutter is raised from the slit. In such a case the blades will offer a minimum resistance to the further lifting of the cutter.

An optimum distance between the blade fulcrum and the fulcrum of the resultant of the forces applied to the blades depends on the nature of the ground on which the drain layer operates. It is practicable that the drainlayershould be provided with a device for adjusting the position of the point where the rod extensions intersect each other, the rods connecting the cutter with link and with the blades rigidly mounted on the latter. This point serves as the centre around which the blades turn. The rear end of the upper rod is articulated to the slide while the latter is movable along the guide which is installed on the link.The movement of the slide along the guide changes the position of the upper rod and, as a consequence, the location of the point of intersection of the expansions of both rods, thus optimizing the distance between this point of application of the force acting on the blades. If the guide is rectilinear, this adjustment involves an undue turning of the link and blades. To avoid this turning, the guide is preferably arcuate with the centre thereof located on the hinge axis of the front end of the upper rod.

It should be pointed out that the present invention can be realised by conventional technical means and do not call for working out new units, mechanisms, and assemblies which have not been manufactured heretofore by the industry. This applies both to the automatic control device and to the mechanical elements. These factors ensure good functioning and low cost of the ditchless drainlayer.

The invention will be described further, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic representation of a ditchless drainlayer comprising a cutter secured to a frame; Figure 2 is a version of the ditchless drainlayer wherein the frame is articulated to the cutter; Figure 3 is a diagram of the connection of the swivelling supporttothe cutter with provision for adjusting the position of the instantaneous centre of velocities; Figure 4 is similar to the diagram shown in Figure 3 but with a curvilinear guide of the slide; Figure 5 shows a device for raising the cutter with the drainlayerstationary (working position); Figure 6 is similar to the diagram shown in Figure 5 with the cutter being raised from the slit.

The ditchless drainlayer (Figure 1) comprises a working element or cutter 1 which is connected rigidly to a frame 2 whose front end is articulated to the rod of a hydraulic piston-and-cylinder unit 3 intended for turning the working element, the cylinder of the unit 3 being connected to the prime mover (not shown). The drainlayer also comprises two cutter control systems, viz. a system of angular stabilization and a system for controlling the height of the cutter.

The angular stabilization system comprises a transmitter 4 of the angular position of the cutter, mounted on the frame 2, an amplifier-converter 5, and the hydraulic unit 3. The angular position transmitter 4 may be of any convenient type (e.g. pendulum or liquid).

The system controlling the height of the cutter comprises a height transmitter 6 mounted on the frame 2, an amplifier-converter 7, a connecting link 11 connected to the cutter 1 by two rods viz. an upper rod 9 and a lower rod 10, whose front ends are articulated to the cutter 1 while the rear ends are articulated to a connecting link 11 and blades 8 rigidly attached to the link 11 and projecting sideways. Installed between the blades 8 or the connecting link 11 and the cutter lisa hydraulic cylinder 12 of the swivelling support.

The height transmitter 6 may be of any type suitable forthe type of the drainage line requiring specific depths and gradients during laying of drainpipes. The datum line can be a tracing wire, a laser beam, or the optical axis of a sighting device, for example. The transmitter should be of a corresponding type.

As can be seen the upper and lower rods 9 and 10 are installed in such a manner that their extensions intersect at point B located in front as the machine goes. Thus, the rods 9 and 10, the cutter 1, and the connecting link 11 form a four-bar mechanism with non-parallel upper and lower sides.

In the embodiment shown in Figure 2 the frame 2 is articulated to the cutter 1 at one end and to the prime mover at the other, while the hydraulic unit3 for turning the cutter 1 is installed between the frame 2 and the cutter 1. In this embodiment the transmitters 4 and 6 are mounted directly on the cutter. In other respects the embodiment comprises similar parts and units both regarding their function and location.

An embodiment wherein provision is made for changing the position of the point B of intersection of the rods 9 and 10 is shown in Figure 3. In this version the rear end of the upper rod 9 is articulated to a slide 13 for changing the angle of convergence of the rods 9 and 10, and the connecting link 11 carries a guide 14 of the slide 13, the guide being articulated to the rear end of the lower rod 10. Connected between the slide 13 and the guide 14 is an additional hydraulic piston-and-cylinder unit 15 for moving the slide 13 along the guide 14. In the embodimenu shown in Figure 3, the guide 14 is rectilinear.

The embodiment illustrated in Figure 4 is identical with that illustrated in Figure 3 except that it has a guide 16 is curvilinear, bent along an arc centred on the hinge axis of the front end of the upper rod 9.

The ditchless drainlayer can be fitted with a mechanism which raises the cutter from the ditch without moving the drainlayer forward or back. As shown in Figures 5 and 6 the connecting link 11 is provided with a sector 18 mounted on a horizontal transverse pivot 17 and the blades 8 for controlling the height of the cutter are rigidly secured to the sector 18. The sector 18 is secured, during drain laying, by a stop 19 with a control rod 20 and a spring 21.

The ditchless drainlayer described above operates as follows.

The drainlayer digs into the ground to the required initial depth in a hole or trench dug in advance and starts its progressive movement, laying a drainpipe on the bottom of the trench. The transmitter 6 of the angular position of the cutter continuously sends signals about any deviations of the angular position of the working element from the required direction.

The amplifier-converter 5 transforms these signals into commands entering the hydraulic unit3 which turns the cutter. The cutter is turned either together with the frame relative to the prime mover (Figure 1) or relative to the frame (Figure 2). Simultaneously, the height transmitter 6 continuously measures the deviations of the height of the cutter (more accurately, the height of its cutting point A) or the depth of the trench from the required value. Tis deviation is measured by the transmitter 6 with relation to a datum line which is set by one of the known methods: tracing wire, laser beam, sighting line of an optical instrument, etc.

After being amplified and converted in the amp lifier-converter 7, the signals of this transmitter 6 act in the form of actuating commands on the hydraulic unit 12 which turns the elements controlling the height of the cutter. The hydraulic unit 12 turns the connecting link 11 and the blade 8 which are connected rigidly to the link and which control the height ofthe cutter.

The simultaneous operation of both abovementioned transmitters, i.e. stabilization of the cutter with respect to angular position and height, weakens considerably the effect of the disturbing factors which tend to distort the trajectory of the cutter. This ensures actual independence of the laying accuracy and speed from the irregularities of the ground surface traversed by the prime mover and from the chance forces acting on the cutter. The high operating speed of the height control system is achieved due to the fact that the connecting link 11 and the blades 8 are connected with the cutter 1 by two articulated rods 9 and 10 which form, together with the cutter 1 and the connecting link 11 a four-bar mechanism with the upper and lower sides converging in front. The point B where the extensions of these rods intersect is the instantaneous centre of the speeds of the turning blade.Such an arrangement ensures a considerable distance between the centre of turning of the blades (this centre serving as an imaginary hinge securing them to the cutter) and the centre of pressure, i.e. the point of application of the lifting controlling force acting on the cutter. The larger this distance, the higher will be the operating speed of the control system. However, the blades do not perform only plane-parallel motion but also turn somewhat in the process of control. In the equilib rium position they are set at a certain angle of attack causing a vertical component which counters the tendency of the cutter towards penetration into the ground under the effect of its weight and the shape of the cutter point on which arises a downwarddirected component of the ground reaction which improves substantially the condition of control.

The position of the instantaneous centre B of turning of the blades may have to be adjusted to suitthe changes in the physical and mechanical properties of the ground because the operating speed of the system must vary for different kinds of soil. Such an adjustment is ensured by the hydraulic unit 15 (Figure 3) which moves the slide 13 and, jointly with it, the rear hinge of the upper rod 9 up or down along the guide 14. Changes in the relative positions of the rods 9 and 10 change the angle between them and bring the instantaneous centre B of blade turning either nearer or farther. In the version illustrated in Figure 3 this will change the angular position of the blades 8, which, in this case, will be corrected by the hydraulic unit 12, which will turn the blades to an equilibrium position.

The mechanisms shown in Figure 4 does not call for such additional adjustment because the action of the hydraulic unit 15 does not turn the blades 8, since the slide 13 moves along the arcuate guide 16 whose centre lies on the axis of the front hinge of the upper rod 9.

In the course of drain-pipe-laying it may become necessary to raise the cutter from the drain slit with the prime mover immovable. This may be necessistated by, for example, an encounter with an unsurpassable obstacle (e.g. a large boulder), also during operation in crampled conditions, when the drain slit ends close to a man-made structure. The blades biting into the walls of the slit interfere with such raising.

The device illustrated in Figures 5 and 6 make such raising possibie. For this purpose the operator pulls back the stop 19 by means of the control rod 20 so that the sector 18 may turn freely in the hinge 17 relative to the connecting link 11 to the position shown in Figure 6 as the cutter is raised. Then the blades 8 offer minimum resistance to further extraction of the cutter from the ground.

It can be seen that the above-described ditchless drainlayer is provided with a highly efficient system of coupling to the prime mover and of controlling the position of the cutter, which permits laying horizontal culverts with an accuracy which meets the most exacting demands and at a laying speed which is limited only by the tractive capabilities of the prime mover in various soils on terrain with but insignificant surface irregularities. The drainlayer does not have any additional complications involved in the use of new, hitherto unknown, units and compo nents.

Claims (6)

1. A ditchless drainlayer comprising a frame, a cutter secured to the frame, a transmitter of the angular position of the cutter, a hydraulic piston and-cylinder unit for changing the angular position of the cutter, the said unit being controlled by the said transmitter via an amplifier-converter, a trans mitter of the height of the cutter, a link rigidly mount ing two blades which project sideways at the rear of the cutter, the link being articulated to the cutter by an upper rod and a lower rod which converge in the forward direction and whose imaginary extensions intersect, and a hydraulic piston-and-cylinder unit for turning the link about the point of intersection, the latter unit being controlled by the height transmitter via an amplifier converter.

2. A drainlayer as claimed in claim 1, wherein the link includes a rotatable sector provided with a releasable stop, the blades being rigidly secured to the sector.

3. A drainlayer as claimed in claim 1 or 2, including a slide articulated to the rear end of the upper rod and guided by a guide which is articulated to the rear end of the lower rod and which is attached to the link, and a hydraulic piston-and-cylinder unit for moving the slide along the guide in order to change the convergence angle of the rods.

4. A drainlayer as claimed in claim 3, wherein the guide is rectilinear.

5. A drainlayer as claimed in claim 3, wherein the guide is arcuate and is centred on the hinge axis of the front end of the upper rod.

6. A ditchless drainlayer substantially as described herein, with reference to, and as shown in, Figure 1, or Figure 2, or Figure 1 or 2 as modified by Figure 3 or Figure 4 or Figures 5 and 6 of the accompanying drawings.