CA2155312A1

CA2155312A1 - Excavating equipment

Info

Publication number: CA2155312A1
Application number: CA002155312A
Authority: CA
Inventors: Lipsker Yitshaq
Original assignee: Individual
Current assignee: Helfgott & Karas Pc
Priority date: 1993-02-22
Filing date: 1994-02-22
Publication date: 1994-09-01
Also published as: IL104820A0; EP0725757A4; WO1994019272A1; PL176583B1; EP0725757A1; RU2124609C1; IL104820A; PL310128A1

Abstract

Excavating equipment comprising a rigid support structure (1) with surface clamping means (18) articulately mounted thereon; excavating means (2) downstream of the surface clamping means (18) in a direction of excavation power means (7) coupled to the excavating means (2) for operating same and coupled to the surface clamping means for displacing them against rigid supporting surfaces so as to generate a counter-reaction to forces generated by operation of the excavating means; and equipment displacing means (20) coupled to the support structure for displacing the equipment into and out of an excavation. Alternately, when the equipment is used for excavating in rocky sites, the equipment can comprise a first rigid support structure (1) articulated to the first structure and a second rigid support structure (35) articulated to the first support structure; expansion means for displacing the second rigid structure with respect to the first rigid structure rotary milling means (34) mounted on the second rigid structure; and power means (36) coupled to the rotary milling cutters for operating same.

Description

2 1 S 5 3 1 2 PCT~S~101~7 EXCAVATING EQUIPMENT

FIELD OF THE INVENTION
The present invention relates to excavating equip,l.cnt particularly to such equip~nent for use in excavating a relatively deep hole of substan-tially rectangular cross-section shape for use in the formation of support 5 piles or the like or in the excavation of elongated trenches or ditches for use in the pre~aralion of foundation elements or for the construction of diaphragm walls.

BACKGROUND OF THE INVENTION
10Known equiplllcnt for use in such forms of excavation have generally involved the use of very tall cumbersome cranes from which are s~cpende~l heavy support structures which carry at their lowermost ends suitable excavating equipment such as cl~m~hells or millin~ cutters or the like. Clearly the use of such tall cranes is very cumbersome and is restricted 1~ to sites readily acce~ible by such large cumbersome equip~ent. Further-more, such tall cranes require significant power sources for their operation.
Furthermore, with such known eq~ ,cnt, preliminary holes or trenches SUBST~TUTE SHEEI (RUL~ 26) - ~ - 2155~12: ` 94~v~
, lS -have to be prepared ~hich are subsequently penetrated by the e~ca- ating equipment and these preliminary holes or trenches have to be suitably reinforced so as to prevent their collapse during the e~cavation procedure.
It is a furthermore Icno-~n disad-!antage ~ith such equipment that, in order to ensure that the excavated holes or trenches are maintained in a stable condition prior to the casting therein of the concrete or the like, the holes as they are being excavated must constantly be filled with a substance such as that kno-~n as bentonite which must be subsequently pumped out during the concrete casting procedure.
0 There have been disclosed in the Applicant's prior patent specifications U.S. Patents Nos. 4,957,175 and 4,770,256 soil drilling equipmentwherein some of the above-referred to disadvantages are reduced in that, during the drilling procedure, pressure plates are forced against the walls of the hole as they are being drilled, in this way leading to the compacting of the walls and reducing the dangers of collapse. Such prior proposals do not, however, lend themselves readily for use in equipment other than soil drilling equipment for the production of relatively narrow bore holes. In particular, they do not disclose any particularsolution for the problem where the excavation to be effected is of substantiallyrectangular cross-section using for this purpose clamshell excavators or rotary mill 2 o cutters or the like.
It is therefore an object of the present invention to provide a new and improved excavating equipment in ~hich the above-referred to disad-antages are substantially reduced or overcome and the above-referred to desiderata are substantially fulfilled.
BRIEF SUr~l~L~R~ OF THE l~'E~TlO~
According to the present ill~ention there is pro-ided excavating equipment comprising a rigid support structure; a single surface clamping means ~ 3_ 2155312 articulately mounted on each side of said support structure; excava~ing means downstream of said surface clamping means in a direction of excavation; each surface clamping means extending along said support structure substantially the entire width as said excavating means; po~er means coupled to said excavating 5 means for operating same and coupled to each of said surface clamping means for displacing both said clamping means against opposing rigid supporting surfaces so as to generate a counter-reaction to forces generated by operation of said excavating means; and equipment displacing means coupled to said support structure for displacing said equipment into and out of an excavation.
Preferably the excavation mans comprises a pair of clamshell buckets reciprocally pivotable about substantially parallel pivotal axes towards and a-~ay from each other under the influence of the power means.
In accordance with a preferred embodiment of the invention, the surface clamping means comprises a pair of substantially planar pressure plates 5 located substantially normally to the pivotable axes of the clamshell buckets. If desired, a further pair of substantially planar pressure plates located substal-tially parallel to the pivotable axes are provided.
The invention also envisages the provision of compact, mobile structures capable alternatively of operating in confined places or in the vicinity of 20 existing structures such as walls or the like or in open spaces. These compact structures are provided with means whereby preparatory bores or recesses can be formed by the excavating means themselves with the pressure plates being pressedagainst the walls of these preparatory recesses as e~cavation proper begins.
In accordance with an alternative preferred embodiment of the 25 present invention, there is provided a first rigid support structure; a single surface clamping means articulately mounted on each side of said first structure; power means coupled to each of said surface cl~mping means for displacing both said _ 4 _ 215531~
~, .

clamping means against opposing rigid supporting surfaces; a second rigid support structure articulated to said first structure; rotary milling cutters mounted on said second structure; each of said clamping means extending along said first supportstructure substantially equal to the entire -idth of the diameteis of both milling 5 cutters; po-~er means coupled to said rotar~ milling cutters for operating same, forces generated during operation of said excavation means being countered by a counter-reaction generated by displacement of both said clamping means against said opposing supporting surfaces 10 DESCRI PTIO;~i OF TH E DR ~ 'GS
For better understanding, the invention will now be described, b~ ~a~
of example onl~, with reference to the accompan~ing drawings in u-hich Fig. 1 is a front elevation of a clamsllell t~pe exca-ating apparatus according to the present invention with the front pressure member removed and uith the 15 buckets in their open position;
Fig. 2 is a cross-section along line ii-ii in Fig l;
Fig. 3 shows the excavating apparatus suspended within a partially dug excavation with the buckets in their closed position;
Fig. 4 illustrates how the present invention may be used for plating ualls of 2 o an excavation;
Fig. 5 is a schematic cross-sectional illustration of another embodiment of the excavating apparatus shown within a bore;
Fig. 6 is another embodiment of the present invention;
Fi~. 7 is another embodiment ~ccording to the in~ention in which the 2 5 excavating means is a soil milling cutter;
Fig. 8 is an isometric view of a structure suitable for suspending the excavating apparatus shown in a first sus~eIldillg position;
Fig. 9 is a partial cutout view of another embodiment as in Fig 8;

21~5312 .

Fig. 10 is a structure of Fig. ~ in a second suspending position;
Fig. 11 sho--s ho-~ the present in~ention may be attached to a con--entional tow truck;
Fig. 12 illustrates how the in~ention maybe mounted on a drill truck;

w o 94~19272 2 1 55 3 1 2 Pt~rnUSg4101777 , _ Fig. 13 is a front view of a further embodiment of the present ~nvenhon;
Fig. 14 is a side view of the embodiment of Fig. 13;
Fig. 15 is a cross-section along line xv-xv in Fig. 14;
Fig. 16 is a cross-section illustrating how lateral brackets may be produced in diaphragm walls, employing the present invention;
Fig. 17 illustrates how the present invention is used for casting strengthened load bearing elements; and Fig. 18 is a cross-section of a strengthened bearing element prepared 10 according to the embodiment of Fig. 17.

DETAILED DESCRIPIION OF SPECIFIC EMBODIMENTS
Reference is first being made to Figs. 1 to 3 of the drawings in which a cl~m~hell type excavating equipment consists of rigid support 15 structure 1 to which are pivotly articul~ted two cl~m~hell buckets 2 or shovels about pivotal axes 3. Each of the buckets is also pivotly linked at 4 to piston rods 6 of hydraulic cylinders 7 which pistons are themselves pivotly linked at their opposed end 8 to the structure 1.
A hydraulic control unit 9 is connected via fluid pressure supply '~O line 10 to a power source (not shown) and has a first pair of conduits 11 connected to one end of the cylinders 7 and a second pair of conduits 12 conn~-c1e~1 to an ol.posile end of the cylin~ers The arrangement is such that upon dilc~;lh~g pressurized fluid through conduit 12 and out of conduits 11, the piston rods 6 retract into the ~5 cylinders 7, whereby, the buckets 2 move into their opened position as shown in Fig. 1 and upon directing plcs~uliGed liquid through conduits 11 and out of conduit 12, the piston rods 6 extend out of the cylinder 7 and the buckets 2 move to their closed position as illustrated in Fig. 3.

SUBSTITUTE SHEET (RULE 26) 6 _ 21 5531 2 Two pairs of cylinders 15 are mounted on respecti~e ends of the support structure I ~ ith their longitudinal a~es parallel uith the axes 3 of the buckets 2 and are connected via conduits 16 to the hydraulic control unit 9. Each cylinder 15 has two axially opposed cylinder rods 17 (see Fig. 2) to ~hich are s connected a single -ertical pressure plate 18 on either side of the support structure (both seen in Fig. 2 but for the sake of clarity of understanding one of the plates is shown removed in Figs. 1 and 3). Each pressure plate extends for a u idth substantially equal to the width of the buckets 2 in this closed position and as sho~n in some of the Figures, even as ~-ide as the span of the buckets in this open position.
The arrangement is such that upon application of hydraulic pressure to the c~linders 15, the cylinder rods 17 extend and the pressure plates 18 are displaced apart whereas upon retraction of the cylinder rods 17 the pressure plates 18 come together.
Two support structure I further has at its top end a hoisting ring 19 for connecting a hoisting cable 20.
For excavation, the equipment is brought to the site uhere it is required and where an initial shallow hole has been prepared by kno~n means.
Such a preparatory hole should be deep enough so as to accommodate the pressure plates 18 of the excavating equipment. Then, the equipment is lo~ered into the 2 o preparatory hole by any suitable hoisting means and with the buckets 2 in their open position, and hydraulic pressure is applied from an external power source (not sho~n) through supply line 10 and conduits 16 and to pistons 15, ~hereby, the pistons expand resulting in the pressure plates 18 clamping against the ~-alls of the preparatory hole thereby forcing the equipment in position.
2s Hydraulic pressure is applied through conduits 11 to the cylinders 7 resulting in,the buckets 2 pivoting togetller at the same time digging into and gathering up excavated soil. The piStOI1S 15 are contracted releasing the pressure -- 215 5 3 i~

plates and the exca~ation equipment is hoisted by the cable 20 and the excavatedsoil is remo~ed by suitable kno-~-n means. The equipment is again lo~-ered deeper into the exca~ation to perform another sequence of exca~ating as described abo~e.

wo 94/19272 2 1 5 5 3 1 2 PCT/US94101777 Where it is desired to excavate an elongated ditch or trench, a preparatory correspondingly elongated shallow trench is prepared and excavation proceeds gradually in a direction parallel to the planes of the pressure plates. Alternatively pairs of separated holes can be excavated and subsequently the bounding region b~l~eell the excavated holes is excavated.
Where required, the elongated trench can be of any required shape.
Each time the pressure plates 18 are pressed against the walls of the excavation, the walls are continuously compacted, whereby, caving in and creeping of the excavation walls are avoided. This feature renders the 10 use of the excavating equipment highly cost effective.
Furthermore, by adding suitable gauges responsive to the stroke of the piston rods 17 and to the pressure within conduits 16, it is possible to determine any lateral dimensional changes of the excavation walls as well as their colllpressibility which generates a real time indication regarding 1~ comp~ctnes~ of the soil and indicating whether cavities exist or caving in has occurred during excavating.
For the eventuality that caving in has occurred, or if a pre-exi~ting cavity was detected during the excavation, as illustrated in Fig. 4 of the drawings, a concrete plating board 22 or other suitable material can be 0 attached by readily detac-h~kle catc-he~ 23 to one of the pressure plates 18 and the excavating equipment is lowered to the correct depth and the pl~s:~ur~, plate 18 with the attached plating board 22 is extended so the latteris pressed until it becomes flush with the wall of the excavation, covering the cavity and straight~onin~ the wall of the excavation. This enables a 2~ diaphragm wall of uniform thickness to be cast without the formation of excessive concrete bulges in such cavities.
By way of another application of the invention, the e~lui~llent may be used not only for comractin~ and plating the walls of an excavation as already explained, but also for improving stabilization of the walls by SU~ 1~ 1 ~rE SHEE~ (RULE 26) wO g4/19272 - PcTluss4lol777 2 1 ~ 1 2 - 8 -pressing a metal net or stabilizing granular materials such as gravel, into the walls.
Reference is now made to Fig. S which is a schematical top view of an a~aralus according to the present invention which comprises two pairs of opposed p~e~u~e plates 18 and 25, lespe~ ely located in planes perpendicular to each other. The first pair 18 (bearing the same reference numeral as in Fig. 2) lies in a plane parallel with the plane of swinging of the buckets 2 and the second pair 25 is disposed perpendicular to the first pair. This arrangelllellt is for use in excavating holes of a width not 10 excee~ling the maximum span of the buckets 2 and the maximum expansion of the pistons of the side pressule members 25. However, by using such pressure members in two normally directed axes, as illustrated, an excava-tion is obtained in which all the walls are compacted.
Attention is now made to Fig. 6 which is a modified form of the 1~ pl~sent invention in which those elements which are similar to those of the embodiment of Fig. 1 are clecig~ted with similar reference numerals.
According to this embodiment, the rigid support structure 1 accommodates an electric motor 27 connected to an hydraulic motor 28, a plCS~ule fluid reservoir 29 and an electric control unit 31 adapted to receive 20 signals from the operator either by an electric cable 32 or by transmitted si~lc, whereby electric signals are yielded by the control unit and transferred to the electric motor 27, by means of an electric cable 33. The advantage of this embodiment is that less energy is lost throughout the long hydraulic lines 10 of the previous embodiment of Fig. 1 and where the comm~n~lc are transmitted to the electric control unit 31, the need for a collecting pulley is obviated.
Fig. 7 of the drawings shows how the present invention may be applied to excavating e.~uit>me.lt employing soil milling cutter also known as a hydromill, useful for excavating in hard soil or in rocky sites. For the SUB~TITUTE SHEET (RULE 26) ~, sake of simplicity, similar elemen~s are marked with the same reference ~'u`rnerals as~~ ~ ~ ~
in ~igs. 1 to 3. In this embodiment, the exca~ating is performed by t~o soil milling cutters 34 rotatably mounted on a second rigid structure 35 ~ertically disposed below the ~lrst rigid structure 1 and connected thereto by tuo ~ertical pistons 36. the overall extent of the width of the two milling cutters being substantially equal to the width of each of two opposing pressure plates 18, or slightly larger. Each of the pistons is connected at a top end 37 to the first rigid structure and at a bottom end 38 to the second rigid structure 35 and is pro~-ided with a hydraulic conduit 39 for ~ertically expanding or contracting the pistons 36, thereby vertically displacing the o second rigid structure with respect to the first rigid structure. The milling cutters are driven by hydraulic motors (not seen) in opposed directions, the motors receiving fluid pressure via conduits 39a.
The apparatus further comprises, as in the previous embodin-ents, pressure plates 18 (one of which is shown removed for the sake of clarity) which can be expanded or contracted by means of hydraulically operated pistons 15. A
hydraulic control unit 9 provided with pressure inlet conduit 10 and outputs 16, 39 and 39a is provided for controlling the expansion-contraction of the pistons 15 and 36 and the operation of the mill cutters 34 by their respective motors. In accordance with such an embodiment, the excavated soil is removed from the dig by flushing 2 o means (not shown) as known by those skilled in the art.
An excavating procedure is performed as already explained, by first digging a preparatory hole deep enough to accommodate the pressure plates and then by gradually lowering the mill cutters by expanding the cylinders 36, thus deepening the dig while clamping the pressure plates against the walls of the dig.
Reference is now made to Figs. 8 to 10 in which are illustrated a mobile constructions 40 for use in alternati-e modes of exca~ation as ~

- 9a - 2155~12 hereinafter be explained and which effecti-/ely cope ~ith the preparation of the initial hole or trench.

,~ ~ ~, .. . . .. .

wo 94/19272 ; ; pcr/us94101777 2155~12 - lo-ln a first mode of excavating, as illustrated in Fig. 8, the construction is used when it is required to excavate adjacent a vertical existing structure such as a wall. In this case, the excavating equipment generally design~ted 41, is mounted on a rigid boxlike structure 40a and is suspended by cable 20' from a first pulley 42 and over a second pulley 46.
A hydraulic supply line 10' runs parallel with the cable 20' and rolls over pulleys 42' and 46' respectively. As illustrated, the cable 20' and the supply line 10', are picked up by winch 47 and pickup spool 48, respectively. The power required for the winch and for pressurizing liquid through the supply I0 line is obtained from any power source of any known type integral with, or separate from the mobile construction and not shown in the figures.
This mode of excavation is carried out by locating the construc-tion 40 with the excavating equipment 41 adjacent the vertical structure (not shown) and over a preparatory hole dug beforehand (not shown) and then, 15 procee~ling as already explained, with the ~les~ule plates 18 clamping again~t the walls of the excavation.
Alternatively, and as illustrated in Fig. 9, there is mounted on an ç~rtçrn~l wall 51 of the boxlike rigid structure 40a two laterally slidable brackets 52 with an e~p~nding plessùle member 53 therebetween, adapted 20 for eXpqnfling or contracting the b-ackets 52 within a suitable slot 54 in the pressure plate 18" facing the construction, which together with the brackets 52 forms a dovetail arrangement.
With this arrangement, it is possible to form the initial l,ieparatory bore or trench by means of the e~uiplnellt's cl~m~hell buckets th~ elves 25 which are ach1ated into an excavating condition with the nPcesSs.~ counter-reaction being obtained by the brackets 52 clampingly locking within the slot 54 of the l reaaule plate 18". The construction is stabilized by its self weight or, if nece~s~r~ by additional anchoring means as known in the art.

SUBS~ITUTE SHE~ (RULE 26) wo 94/19272 215 5 312 PCTIUS94/01M7 - .

In a second mode of operation, the construction is used for excavating in obstacle free ground. According to this mode, i]lustrated in Fig. 10, the excavating apparatus 41 is accommodated within the framework of a boxlike rigid structure 40a and is suspended from a pulley 55 with the hydraulic supply line 10' running parallel to the cable 20' and rolled by a winch and a spool respectively, by means of any suitable power source as already explained.
In operation, after locating the construction in the site of excavation and anchoring it if necessary (e.g. in case of hard or rocky land), 10 the excavating apparatus 41 is lowered to the ground's surface and the pressure plates 18 are exp~nde-J to clamp between the inner walls 57 and 58 of the construction, whereby, a counter-reaction is obtained, enabling the excavating apparatus to penetrate into the ground, and in this way effecting the ~el,aldto.~ hole.
1~ It should be re~li7ed that the power source may be integral with the mobile structure 40, or be a separate stationary power source. Alterna-tively, power from any heavy maçhinery such as tractors or cranes may be obtained. It should also be realized that the construction may also be provided with a soil collecting means as known in the art but not described ~0 and not seen in the drawings. Furthermore, for ~ligging ditches, the consllllction may be wheeled over rails located along the route of the ditch (not shown).
The small dimensions of the construction enable it to be operated also in con~med places such as basements, caves or tunnels, or places with poor accessibility which may require transferring the equipment by helicopter.
In the embodiments of Figs. 11 and 12, it is shown how the excavating appaldtus 41' may be attached to a tow truck 60 or to a drilling truck 61 respectively, m~king use of their integral winch 62 and hydraulic SU~ ~1 1 E 5TE SHEET (RULE 26) wO 94/19272 PcTluss4lol777 2155~12 system, by ad~ling~ if required, a pulley 63 for collecting the hydraulic supply line 10".
Figs. 13 to 15 are a further modification of the embodiment shown in Fig. 1, in which those elements which are similar to those of the embodiment of Fig. 1 are designated with the same reference numerals.
In this embodiment, exp~ncion and contraction of the pressure members 18a and 18b is obtained by two pneumatic infl~t~ble-deflatable air cushions 66 disposed between the pleSsuie members 18a and 18b which pressure members are biased towards one another by a plurality of belleville 10 springs 67 mounted on guide rods 68 and bearing at one end against a shoulder 69 of the rods and at the other end, ~g~in~t the p~es~ure members (see Fig. 15).
Accordingly, when it is required to expand the preS:~Ul'e plates, the air cushions 66 are infl~ted by a pneumatic p,essu~ line (not shown) 1~ overcoll,ing the biasing effect of the belleville springs 67. Now, when it isrequired to contract the ~les~ure plates, the air cushions 66 are deflated and the bevelled springs 67 bias the pressure members into their contracted positions.
In order to guarantee that the ~resaulc members remain constantly 20 parallel with one another, the equipment further comprises a mech~nicm co~.cicting of t~,vo crossed links 70 and 71 (as seen in Fig. 14) pivotly linkedto one another at their centers 72. The first link 70is linked at its top end 73 to bracket 74 of pressure member 18a and at its bottom end 75 to brackets 76 of pre;,~u~ member 18b. The second link 71 is linked at a top '5 end 77 to bracket 78 of pressure member 18b and at its bottom end 79 to bracket 80 of ~lG~ UI~; member 18a. This arrangement ensures that the ,s~ule members 18a and 18b remain constantly parallel with one another and that their axial displacement is identical.

SUBSTITUTE SHEEr (RU~E 26) WO g4/19272 2 1 5 5 3 1 2 ~/US94101777 Digging according to this embodiment is carried out in the same manner as already explained regarding the previous embodiments.
The present invention may also be used for constructing lateral brackets integral with a load bearing element or a diaphragm wall, useful for 5 example for ~u~po~ g ready made ceiling or floor elements.
In Fig. 16, two hollow boxlike elements 81 have their walls 82 releasably attached by fasteners 83 to the respective pressure members 18.
Thus the walls 82 are radially detachable from their respective boxes 81 by means such as solenoids 84, although prior to det~c~ing, the walls 82 are 10 rigid with the boxlike elements 81.
The arrangement is such that after excavating a wide enough hole, the apparatus with the boxes 81 attached thereto (as in Fig. 16) is lowered to the ~e~luiied depth, and then, the expansion means are exp~nded until the ~les~,ure members 18 encounter the inner walls of the excavation. At this 15 stage, the boxlike elements 81 continue their penetration into the earth until they are det?,ched from their walls 82 by activating the rlet~c-hing members 84. Then, the ~vres~ure members 18 are contracted and the apparatus is lifted from the excavation, leaving in place the open boxes 81, thus forming niches in the ground which upon casting with cement, will 20 form the lateral brackets 85 which may be employed for supporting ready made ceilings or floors.
Figs. 17 and 18 illustrate how the invention may be used for prep~in~ load bearing elements of a reinforced structure. According to this modification, in which similar elements were given the same reference ''5 numerals as in the previous embodiments, the pressure plates 18 are connected to a first pair of pistons 87 (only one seen) and a second pair of pistons 88 below said first pair 87.
The arrangement is such that the stroke of said second pair of pistons 88 is greater than that of said first pair of pistons 87, whereby, when SUBSTITUT~ SHEET (RULE 26~

wO g4119272 ~ PCrlUS94/01777 the pressure plates 18 are pressed against the walls of the excavation, the walls have a trapezoid-like cross-section which, after casting with cement significantly strength~.nc the load bearing element 89, as illustrated in Fig.18.
Whilst in the embodiments specifically described above, the excavating equipment has always been employed in effecting substantially vertical excavations, the invention is equally applicable for use in substan-tially horizontal excavation such as for example, tunneling. Here, however, additional power coupling must be provided for excavating equipment seeing that in this case gravity is not effective in ~csicting the actual excavation.

SU~ JTE SHEEl (RULE 26)

Claims

CLAIMS:

1. Excavating equipment comprising a rigid support structure; a single surface clamping means articulately mounted on each side of said support structure;
opening and closing excavating means downstream of said surface clamping means in a direction of excavation; each surface clamping means extending along said support structure in the direction of opening and closing; power means coupled to said excavating means for operating same and coupled to both said surface clamping means for displacing each of said clamping means against opposing rigid supporting surfaces so as to generate a counter-reaction to forces generated by operation of said excavating means; and equipment displacing means coupled to said support structure for displacing said equipment into and out of an excavation.

2. Excavating equipment according to Claim 1, wherein said excavating means comprises a pair of clamshell buckets reciprocally pivotable about substantially parallel pivotal axes towards and away from each other under the influence of said power means.

3. Excavating equipment according to Claim 2, wherein each of said surface clamping means comprises a substantially planar pressure plate located substantially normally to said pivotal axes.

4. Excavating equipment according to Claim 3, wherein there is furthermore provided a further pair of substantially planar pressure plates located substantially parallel to said pivotal axes.

5. Excavating equipment according to Claim 3, wherein said power means comprises a first set of hydraulically operated pistons displaceable within, cylinders rigidly mounted on said support structure and articulated to said pressure plates.

6. Excavating equipment according to Claim 5, wherein said pressure plates are spring biased towards each other.

7. Excavating equipment according to Claim 3, wherein said power means comprises a pair of pneumatic inflatable air cushions respectively biased against said pressure plates against said spring biasing.

8. Excavating equipment according to Claim 5, wherein said power means furthermore comprises a second set of hydraulically operated pistons displaceable within cylinders rigidly mounted on said support structure and articulated to said excavating means.

9. Excavating equipment according to any one of the preceding claims, wherein said rigid support structure comprises a mobile displaceable boxlike frame and wherein said equipment displacing means comprises a hoisting cable coupled at one end to said equipment and passing over a pulley arrangement mounted on said boxlike frame, said equipment being suspended adjacent an end wall of said boxlike frame.

10. Excavating equipment according to Claim 9, wherein there is furthermore mounted on said end wall a pair of extendable reaction members coupled to said excavating means the arrangement being such that operative displacement of said excavating means is accompanied by a counter-reactive forcecreated by resistance to displacement of said extendable reaction members.

11. Excavating equipment comprising a first rigid support structure; a single surface clamping means articulately mounted on each side of said first structure; power means coupled to each of said surface clamping means for displacing both said clamping means against opposing supporting surfaces; a second rigid support structure articulated to said first structure; expansion means fordisplacing said second rigid structure with respect to said first rigid structure; rotary milling cutters mounted on said second structure for rotation about individual axes;
each of said clamping means extending along said first support structure substantially equal to a cumulative width of said rotary milling cutters perpendicular to the rotary milling cutters axes; power means coupled to said rotary milling cutters for operating same, forces generated during operation of said excavation means being countered by a counter-reaction generated by displacement of both said clamping means against said opposing supporting surfaces.

12. Excavating equipment according to claims 1 or 11, wherein each of said clamping means are respectively provided with successive, axially displacedhydraulically operated pistons of differing strokes so as to impart to each clamping means an inclination which is correspondingly imparted to the compacted walls.

13. Excavating equipment according to claims 1 or 11, wherein there is releasably attached to each clamping means an open ended molding container adapted to be pressed into the excavated walls so as to provide for the subsequent casting of a ledge.