This invention relates to digging machines and refers particularly, though non-exclusively, to a machine for the digging of trenches or similar earthworks and in which can be laid pipes, cables, or other articles.

Background of the Invention

Machines for the digging of trenches and other earthworks are well-known. These can be backhoes or the large trenching machines for the digging of trenches in which can be laid pipes, cables, duct-work or the like. Such machines are normally large, complex, expensive and are difficult to manoeuvre. In general, the operator sits on the machine when in operation. They are difficult to use in confined spaces, and difficulties are experienced in gaining access to confined space such as laneways, the yards of houses, particularly backyards, and other narrow and/or confined spaces.

Furthermore, they are normally single-purpose articles only and cannot be adapted to use for other purposes. This ties-up a large amount of capital for an owner of such a machine which is useable for one purpose only.

It is therefore the principal object to the present invention to provide a digging machine which is of relatively compact dimensions, and which is relatively easily operated.

A further object is to provide a digging machine which has a number of uses. Brief Statement of the Invention

With the above and other objects in mind, the present invention provides a digging machine having a housing, and drive means being adapted to provide motion and steering to the digging machine; the housing including an engine for the provision of power to the digging machine, the engine being adapted to, in use, provide power to an air compressor and a hydraulic pump located within the housing; there being provided a digging means attachable to and extending forwardly of the housing, the digging means being adapted to be driven by the hydraulic pump; the digging machine being controllable by an operator remote from the digging machine by use of a remote control connected to the digging machine. Preferably, the drive means is in the form of a continuous track on either side of the housing, each continuous track including a toothed wheel and a track idler wheel, each toothed wheel being independently driven by the hydraulic pump.

Advantageously, the digging machine has a base upon which is mounted the housing and to which is mounted the drive means. The base has a front and a rear. To the front of the base there is preferably securely attached a sub-frame to which the digging means is

attachable. The sub-frame advantageously has a substantially vertical member integrally attached to a substantially horizontal, forwardly-extending member. To the rear of the sub- frame there may be attached a securing plate to enable the sub-frame to be attached to the base. The horizontal member preferably has an opening extending transversely therethrough so as to releasably receive therein a pin, the pin being to pivotally locate and hold the digging means on the horizontal member. Preferably, the pin is tight fit in the opening. Advantageously, both the pin and the opening are of circular cross-section.

The digging means may be a trench digger, a back-hoe, an auger or a borer. In each instance it can be attached to the sub-frame by the pin. They are all hydraulically driven by the hydraulic pump. When the trench digger is in use, a hydraulic gear box is mounted on the trench digger to drive a shaft. At an inner end the shaft has mounted thereon a driving wheel to drive a digging chain which passes along a chain guide, the chain guide having at its outer end an idler wheel over which the digging chain passes. Preferably, the shaft has an outer end on which may be mounted an auger bit extending horizontally outwardly. Description of the Drawings

In order that the invention may be readily understood, there shall now be described by way of a non-limitative example only a preferred construction of a digging machine incorporating the principal features of the present invention, the description being reference to the accompanying drawings in which: Figure 1 is a perspective view of a first embodiment of a digging machine incorporating the principal features of the present invention;

Figure 2 is a view from one side of the digging machine of Figure 1 , with the side panel of the housing being removed;

Figure 3 is a view similar to that of Figure 2 but from the other side of the digging machine;

Figure 4 is a rear view of the digging machine of Figures 1 to 3;

Figure 5 is a perspective view of the control unit for operating the machine of Figures 1 to 4;

Figure 6 is a diagram representing the operation or characteristics of the digging machine of Figures 1 to 5;

Figure 7 is a perspective view corresponding to Figure 1 of a second embodiment;

Figure 8 is a view corresponding to Figure 7 but with the digging means and the sub-frame removed; and

Figure 9 is a partial side view of the embodiment of Figures 7 and 8.

Description of the Preferred Embodiment

To refer to Figures 1 to 6 of the drawings, there is shown a digging machine having a housing 10 which comprises a top panel 12, two side panels 14 (one each side), a rear panel 16, a lower front panel 18, and an upper front panel 20. The housing 10 is located on a base 22. Within the housing there is located the operating mechanism for the digging machine. The various components are not illustrated in detail nor are they be described in detail. These include an engine 24 having a radiator 26, exhaust 28 and a forced ventilation fan 30 adjacent an opening in the upper front panel 20. There is also an air compressor 32, which is driven by means of a pulley 34 mounted on shaft 36 of air compressor 32. The pulley 34 is driven by a belt 38 which in turn is driven by a pulley 40 mounted on output shaft 42 of engine 24. Output shaft 42 is mounted within a bearing 46 within a bearing housing 48, and also drives an electric clutch 44 for driving a shaft 50 of a hydraulic pump 52. The arrangement of using pulleys, belts, electric clutches, or the like is not to be limited to that arrangement. Gear drives, drive shafts, gear boxes, or other suitable dive- mechanism may be used, if desired. These will be familiar to those skilled in such industries.

Mounted on top 12 is an air intake 54 for the air compressor 32. As can be seen from Figure 2, an air filter and air intake 56 for engine 24 is also provided. A fuel filler pipe 58 with its attendant cap is provided so that fuel for the engine 24 can also be added as required. The radiator 26 has a coolant overflow tank 60. There is also provided a battery 62 to assist with the operation of the machine, and in particularly at starting. To enable the battery to be recharged, there is provided an alternator 64 which is driven by the engine 24 in accordance with normal practice.

The hydraulic pump 52 has normal valve gear and hydraulic line connections at 66. These are in a standard form and thus are not being shown or described in detail.

As is visible on Figure 4, controls for the operation of the air compressor are located at 102. These, again, are relatively standard and are therefore not shown or described in detail. Controls for the operation of the entire digging machine are located at 70 and, again, these are relatively standard and are thus not shown or described in detail. As it is more clearly shown in Figures 1 and 4, a number of lifting hooks or eyes 72 are located on each side panel 14, as is a sleeve for receiving in a releasable manner the control unit for the operation of the device, as will be understood from the following description.

The side panels 14 have a number of louvres 76 which are to assist in air flow through the interior of housing 10. The top 12 has an opening 78 through which protrudes a radiator cap 80 to enable the fluid in the radiator 26 to be replenished as required.

A further opening 82 in upper front panel 20 allows the projection therethrough of a cap 84 to enable the engine oil to be replenished as required. Also on upper front panel is an emergency stop button 86, the purpose of which is to stop all functions of the machine in an emergency. As can be seen from Figure 4, the rear panel 16 has a number of openings 92, 94 and 96. In opening 92 there is located an ignition switch 98 for the control of the operation of engine 24, and a meter 100 for maintaining a record of the hours of operation of engine 24. In second opening 94 there is a stop/start button 102 for the air compressor 34, and the engine throttle 104. In third opening 96 there is located a plug 106 for receiving a corresponding plug (not shown) at the end of a lead (not shown), the other end of the lead having attached thereto the control unit 108, as shown in Figure 5.

Also located in top 12 is an air connector 1 10 having a control valve 1 12 therein. In this way, a compressed air supply to operate underground boring tools is available. With a compressor 32 having a capacity of, for example, 45 cfm it will be of sufficient capacity to operate most required air operated machinery. In this way, those tools requiring air operation can be used without a separate machine being required to provide the necessary compressed air power.

Mounted under the base 22 is the driving mechanism for the digging machine. As is clear from the drawings, this includes two continuous track mechanisms, one on each side of the machine. These include a continuous track 1 14 which is driven by a tooth drive wheel 1 16 and which also passes over an idler wheel 1 18. The wheels 116, 1 18 are mounted on a frame 120. The idler wheel 118 is mounted on a forked mounting 122 by means of an axle 124. The forked mounting 122 is attached to the outer end of a shaft 126 which is mounted within the frame 120. An adjustment mechanism 128 is provided so that the position of shaft 126 within frame 120 can be adjusted to ensure appropriate tension by idler wheel 118 on the continuous track 114. Preferably, the continuous tracks 114 use chain rollers (not shown) instead of the normally provided separate rollers.

The continuous track 114 has a number of links 130 each joined to the adjacent link in a pivotal manner by pins 132. To the links are mounted the track pads 134 which preferably have an outer surface 136 of a material sympathetic to softer surfaces such as, for example, lawns. Preferably, the outer surface 136 is made of a material such as polyurtheyne.

Mounted under base 22 is a lower frame 186 to which are mounted two hydraulic motors

188, 190 for driving the continuous tracks 1 14 via the toothed driving wheels 116. The hydraulic motors 1 18, 1 19 are separately controlled so that the continuous tracks 1 14 can be driven individually, together or separately. In this way, if motor 188 is moving forward

and motor 190 is moving in reverse (or vice versa), their digging machine can be caused to turn in a very small distance, normally approximating its own length.

Attached to the front of the base 22 is the digging mechanism 138, in this case a trench digger. The mechanism 138 is mounted on a sub-frame 140 which has an upright 142 extending upwardly therefrom close to the lower front panel 18. A level 90 to indicate the level of hydraulic fluid is mounted on upright 142.

At the front of sub-frame 140 is mounted a bearing block 144 in which it is mounted one end of a drive shaft 146. The other end of drive shaft 146 is mounted within and driven by a hydraulic motor 148. The hydraulic motor 148 drives shaft 146 so as to provide motive power to a digging chain 150. The digging chain 150 has a number of large digging elements 152 and linking elements 154, as is normal for such a chain. An idler wheel 156 is located remote from the drive shaft 146. The idler wheel 156 is mounted within a U- shape member 158 for rotation relative thereto. The member 158 is mounted on the outer end of a shaft 160, which is mounted on a further shaft 162, with an adjustment mechanism 164 being provided to adjust the position of the shaft 160 relative to frame 162. This is to ensure that the idler wheel 156 places the correct tension on the digging chain 150 to have the chain 150 at the correction tension at appropriate times. The hydraulic motor 148 is provided with its hydraulic power by means of hydraulic lines 166 which are connected to standard hydraulic connectors 168 mounted on lower front panel 20. The connectors 168 are connected to the hydraulic pump 52 by hydraulic lines (not shown) mounted within housing 10. If the digging mechanism 138 is not in use, connectors 168 can be used to enable other hydraulic powered equipment to be operated.

To protect the digging machine during operation, and to protect the operator of the machine, a mud flap 170 is provided as is a guard 172. Mounted on upright 142 by a pivoted connection 174 is a double acting hydraulic ram 176. The rod 178 of hydraulic ram 176 is connected at its outer end in a pivotal manner to a mounting block 180, which is also connected to frame 162 of digging mechanism 138. In this way, the angle of the digging mechanism 138 relative to the horizontal can be varied from the upper position shown in the drawing to a lower, digging position. A range of angles of up to approximately 100° is possible. A stop 182 with a spring 184 therearound is mounted on upright on 142 to provide an end stop for mounting block 180 when the digging mechanism 138 approaches the upright position.

The control unit 108 has a "dead man" switch 192 which must be depressed to have the machine operate. If the switch is released, all machine functions cease immediately. This is to prevent injury to an operator or other persons in the event of an operator tripping over, suffering an illness, or the like, during operation. Other switches on the control unit 108

control the operation of the hydraulic motors 188, 190, as well as the hydraulic ram 176, and hydraulic motor 148. These include a switch 194 for the operation of the drive means 188,190, a switch 196 for controlling the drive speed (high or low speed) of the hydraulic motor 148, a switch 198 for the hydraulic ram 176, and a switch 199 for controlling the machine direction - forward or reverse.

By way of example, the nature of the equipment located within housing 10 may include a water-cool engine such as that manufactured by "Kubota" which may be of petrol or diesel operated. The air compressor may be a standard air compressor, as may be the hydraulic pump. With appropriate equipment, the dimension of the machine according to the invention may be sufficiently small to enable the machine to pass through a standard doorway, and may also be able to be carried in the back of a standard, commercial van, including a panel van.

By having the operator remote from the digging machine, the operator can maintain accurate control, whilst still having full vision to observe the digging functions and the movement of the machine.

Figure 6 shows the inter-relationship of the various components in chart form. The engine drives the hydraulic pump and the air compressor. The air compressor has an outlet to enable the compressed air to be used. A radiator and overflow are used to control the temperature of the engine, in the normal manner. The engine also drives the alternator which recharges the battery. This is all controlled, and serves to control the ignition system of the engine. All functions of the machine are controlled by the emergency stop button 86.

The hydraulic pump 52 uses the valve gear 66 to operate the digging mechanism for driving the chain, the hydraulic ram for the digging mechanism, and the motors for the two continuous tracks. The hand control controls the operation of the various equipment on the valve gear.

Reference is now made to Figures 7 to 9, which show a second embodiment. Like components have a like reference numeral with the addition of a prefix number 2.

The general layout and operation of the digging machine of this embodiment is generally the same as that of Figures 1 to 6 and therefore will not be described. The area of difference is that which is mounted to the front of base 222.

There is shown a digging mechanism 2138, again in the form of a trench digger, which is pivotally and releasably mounted on a sub-frame 2140. Sub-frame 2140 has a vertically extending member 2142 and a horizontally and forwardly extending member 2143 integral with vertical member 2142. To the rear of sub-frame 2140 there is securely mounted a securing plate 2145 to enable the sub- frame 2140 to be securely attached to base 222 by means of bolts or the like 2147.

The digging mechanism 2138 is generally the same as the digging mechanism 138 of Figures 1 to 6, except that it is in mirror image - that is, it is mounted in reverse and is thus on the opposite side of vertical member 2142. The hydraulic motor 2148 is more centrally mounted, but operates in the same manner. The shaft 2146 has at its outer end a horizontally and outwardly extending auger bit 2149 so that as shaft 2146 rotates to cause digging chain 2150 to be driven, and as digging chain 2150 removes earth (when lowered and operating) to form a trench, auger bit 2149 collects the earth and passes it along the spiral path 2151 to remove it from the edge of the trench.

The trench digger 2138 is pivotally and releasably attached to horizontal member 2143 by means of a pin 2153 which is located in a correspondingly sized and shaped opening 2155 extending transversely through the outer end of horizontal member 2143, and which passes through corresponding openings 2161 in the side members 2163 of an inverted U-shaped attachment sleeve 2165 on the lower end of mechanism 2138, the side members 2163 passing over the sides of horizontal member 2143. Pin 2153 and openings 2155, 2161 are preferably of circular cross-section. Therefore, by removing pin 2153 from openings 2155,

2161 , and by releasing hydraulic connectors 2168, the mechanism 2138 can be removed.

The pin 2157 of ram 2176 can also be removed to enable the digger to be completely removed. This will entail also disconnecting hydraulic connectors 2159 for ram 2176.

Alternatively, the pin 2191 connecting ram 2176 to digger 2138 could be removed to enable ram 2176 to remain mounted to vertical member 2142 and thus be useable for an alternative digging mechanism.

The digging mechanism 2138, in being relatively easily removed and attached and hydraulically driven, may be of any suitable form. For example, it can be the trench digger as shown; or may be a back-hoe, auger, borer, or other similar earthworking tool which can be easily removed from and attached to horizontal member 2143, and be operated by appropriate hydraulic connections to the hydraulic pump 52.

If desired the rear of the digging machine may be provided with an easily removable and attachable scraper blade so that earth collected adjacent a trench may be placed back into the trench by having the digging machine move along the trench and the blade force the earth into the trench.

Whilst there has been described in the foregoing description, a preferred construction machine incorporating the principal features of the present invention, it will be understood that those skills and industry concern that many variations or modifications in details on designs of the instruction may be made without departing from the present invention.

It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

It will also be understood that where the term "comprises" or its grammatical variants, is employed herein, it is equivalent to the term "includes" and is not to be taken as excluding the presence of other elements or features.