US3647262A

US3647262A - Roof bolting method and assembly

Info

Publication number: US3647262A
Application number: US1530A
Authority: US
Inventors: Charles W Kacmarcy
Original assignee: Joy Manufacturing Co
Current assignee: Joy Manufacturing Co; Citibank NA; Joy Technologies Inc
Priority date: 1970-01-07
Filing date: 1970-01-07
Publication date: 1972-03-07
Anticipated expiration: 1989-03-07

Abstract

A roof bolting drill assembly for use with a mining machine which assembly is selectively mountable and demountably from the mining machine. Cooperable means are included on the mining machine and roof bolting assembly whereby the assembly is clamped to the mining machines for only linear motion for repositioning and unclamped from the mining machine during a bolting operation to permit limited relative traverse motion of the mining machine for simultaneous mining. A method of utilizing the above structure to carry out a simultaneous mining and roof bolting operation is also disclosed.

Description

United States Patent Kacmarcy Mar. 7, 1972 [54] ROOF BOLTING METHOD AND ASSEMBLY [72] inventor: Charles W. Kacmarey, PO. Box 262,

Franklin, Pa. 16323 [22] Filed: Jan. 7, 1970 [21 Appl.No.: 1,530

Related U.S. Application Data [63] Continuation of Ser. No. 777,313, Nov. 20, 1968,

abandoned.

[52] U.S.Cl ..299/11, 173/23, 173/46, 173/52 [51] Int. Cl. ..E2lc 11/02 [58] Field of Search ..299/l8, 11, 33; 173/23, 24, 173/34, 35, 29, 46; 175/315; 61/45 [56] References Cited UNlTED STATES PATENTS 2,904,319 9/1959 Newton ..299/33 3,199,611 8/1965 Densmore 173/24 3,268,258 8/1966 Kegel ..299/l8 3,493,058 2/1970 Zitko 173/23 Primary Examiner-Ernest R. Purser AtlorneyE. Wallace Breisch [5 7] ABSTRACT A roof bolting drill assembly for use with a mining machine which assembly is selectively mountable and demountably from the mining machine. Cooperable means are included on the mining machine and roof bolting assembly whereby the assembly is clamped to the mining machines for only linear motion for repositioning and unclamped from the mining machine during a bolting operation to permit limited relative traverse motion of the mining machine for simultaneous mining. A method of utilizing the above structure to carry out a simultaneous mining and roof bolting operation is also disclosed.

15 Claims, 9 Drawing Figures PATENTEDMAR 7 I972 SHEET 1 OF 5 INVENTOR CHARLES n. KACMARCY PATENTEDMAR '7 I972 3. 647, 262

SHEET 2 [IF 5 INVENTOR.

CHARL E5 m KACMARW PATENTEDMA R 1 1912 sum 3 OF 5 INVENTOR.

CHARLES H. KACMARCY PATENTEDMAR 1 m2 SHEET U [1F 5 INVENTOR.

CHARLES m KACMARCV PATENTEDMAR 7 I972 3. 647-, 262

sum 5 OF 5 INVENTOR.

CHARLES W K461449627 ROOF BOLTING METHOD AND ASSEMBLY This application is a continuation of application Ser. No. 777,313, filed Nov. 20, 1968 and now abandoned.

Roof conditions in some mines necessitate roof bolting because certain rock strata forming the roof of the mine are not capable of supporting their own weight after the removal of the mineral thereunder. By the use of the present invention, means required for such roof bolting are carried by a forwardly advancing mining machine to the desired roof bolting location and detached therefrom. The roof bolting operation can then be accomplished while the mining machine continues mining forwardly thereof. After such roof bolting is accomplished, the apparatus is hydraulically reattached to the mining machine and brought forwardly towards the mining end thereof.

With a roof bolting apparatus of this invention the bolting operation can proceed without interrupting the mining operation; there is no need to be confined to a miner of the ripper bar type for the mining machine can move forward without interferring with the roof bolting operation; conveying the roof bolting apparatus by means of a mining machine helps to insure an operators safety and speed production; the forwardly advancing mining machine can move laterally within predetermined limits without affecting the roof bolting operation; and no mining personnel need be exposed to the risk of working under an unsupported roof.

These and other objects and advantages of this invention will be more readily apparent from a reading of the following detailed description and drawing in which:

' FIG. 1 is a schematic representation of a mining machine provided with the semisatellite roof bolting apparatus of this invention;

FIG. 2 is a side view of the roof bolting apparatus of this invention mounted in position on a mining machine;

FIG. 3 is an elevational view of the roof bolting apparatus shown in FIG. 2;

FIG. 4 is a cross-sectional view taken on lines 4--4 of FIG. 2 and showing, primarily, a way clamp hinge assembly;

FIG. 5 is an end view of a portion of the hinge assembly shown in FIG. 4;

FIG. 6 is a cross-sectional view taken on lines 6-6 of FIG. 2 showing, primarily, a way clamp cylinder assembly;

FIG. 7 is an end view of the way clamp cylinder assembly of FIG. 6;

FIG. 8 is a cross-sectional view taken on lines 8-8 of FIG. 2 showing, primarily, a traverse drive mechanism; and

FIG. 9 is a partial cross-sectional taken on lines 9-9 of FIG. 2 showing, primarily, a traverse drive idler.

Referring to FIG. 1, a mining machine 14 is supported in any suitable manner, and rendered movable over a floor 16 by a pair of well-known endless circulating crawler tracks 18. Crawler track cover plates 20 are fixed to the crawler frame of machine 14 at the lateral sides thereof and a roof bolt assembly of this invention, generally indicated at 22, is secured to such plates 20. As hereinafter described in detail assembly 22 is capable of being selectively mounted or associated and dismounted or disassociated from machine 14. These terms as hereinbelow used shall refer to a relationship between assembly 22 and machine 14 whereby: associated designates a supported condition of assembly 22 wherein assembly 22 is completely supported by machine 14 and a sliding relationship exists between machine 14 and assembly 22; and disassociated designates a supported condition of assembly 22 wherein assembly 22 is self-supported (i.e., machine 14 has no portion thereof in supporting contact with assembly 22) and a loose guiding relationship exists between machine 14 and assembly 22.

Roof bolt assembly 22 includes a plurality of components which allow such assembly 22 to be selectively captively disassociated from machine 14 when it is desired to place a roof bolt support in a roof of a mine passageway while still continuing the forward advance of machine 14. Such components of the roof bolt assembly 22 are affixed to an elongated panel plate 24 which in turn is secured to the track cover plates 20 by means of a pair of elongated V-jaw rail clamps 26 which traverse the major extent of panel plate 24 and are hingedly connected thereto at the upper and lower sides thereof. As hereinafter described in detail, clamps 26 are selectively clamped or associated to a pair of V-rails 28, which traverse the major extent of cover plates 20 and are rigidly affixed thereto at the upper and lower sides thereof, such that machine 14 carries assembly 22 therewith during a forward movement thereof and provides a sliding relationship therebetween as hereinafter described, or, unclamped or disassociated from rails 28 an amount for which rails 28 provide a guiding relationship with clamps 26. As shown clamps 26 have concave surfaces which interfit with and partially encompass reciprocal convex surfaces of rails 28. The sliding relationship between rails 28 and clamps 26 hereinabove described allows substantially only linear motion of assembly 22 with respect to machine 14 and the guiding relationship thereof allows limited relative transverse motion between assembly 22 and machine 14 as hereinafter described.

The components of assembly 22 hereinabove mentioned which allow the selective association and disassociation of assembly 22 from mining machine 14 include: a hydraulically operated ceiling jack 30 and a hydraulically operated floor jack 31 which are secured to panel plate 24 intermediate the axial ends thereof; and a hydraulically operated elongated jaw clamp cylinder 32 (FIGS. 6 and 7) which is located intermediate the axial ends of clamps 26, extends perpendicular to clamps 26 and is hingedly connected thereto by hinge means 34 (FIG. 6) which, hinge means 34, comprise lug portions 36 which extend outwardly from clamp 26 and removable pins 38 which hingedly secures portions 36 to the axial ends of cylinder 32.

The clamps 26 are hingedly secured to assembly 22 adjacent the longitudinal ends thereof by hinge means 40 and 42 which secure, respectively, the upper and lower clamps 26 (FIG. 4), to the upper and lower portions of panel plate 24. Hinge means 40 and 42 comprise: a lug portion 44 which is rigidly secured to panel plate 24 and extends outwardly therefrom (outwardly being defined as away from machine 14); and a swivel plate 46 which is hingedly connected to lug 44 adjacent the outermost end thereof by a removable pin 48 and extends inwardly therefrom to an innermost end thereof which is rigidly secured to a clamp 26.

By means of the components set forth hereinabove the assembly 22 can be disassociated and associated from the mining machine 14 by selectively supplying, from any suitable source, hydraulic pressure fluid initially to either the jaw clamp cylinder 32 or the ceiling and floor jacks 30 and 31, respectively. To accomplish such disassociation of an assembly 22 which is presently associated (or clamped in a carrying position) to machine 14, hydraulic fluid is initially supplied to the ceiling jack 30 and floor jack 31, thereby causing piston rods 58 and 60 respectively, to extend, respectively, toward the roof 62 and floor 16 of the mine passageway. When the free ends of rods 58 and 60 respectively contact roof 62 and floor 16, the pressure fluid will continue to build up a pressure within jacks 30 and 31 until such pressure reaches a predetermined value which can hold assembly 22 in a stationary or anchored position without any dependency upon V-rails 28 and clamps 26. When such a predetermined pressure value is obtained, a pressure operated sequence valve (not shown), which is of any suitable construction and is positioned in a pressure fluid line extending between the jacks 30 and 31 and jaw clamp cylinder 32, is automatically opened thereby permitting pressure fluid to flow to the head end of jaw clamp cylinder 32. Such pressure fluid causes a piston rod 64 of cylinder 32 to extend upwardly, thereby, because of the particular configuration of hinge means 34, 40 and 42 hereinabove described, releases the assembly 22 from any direct association with machine 14. The vertical movement of clamps 26 is limited by upper and

lower stop plates

66 and 68 respectively, which are firmly affixed to panel plate 24 on the inner side thereof, (inner being defined as that side closest to the mining machine).

Plates

66 and 68 are positioned vertically adjacent clamps 26 at a predetermined distance therefrom to restrict the vertical movement of clamps 26 to an amount which will permit clamps 26 to clearly disassociated from rails 28 while still permitting a loose guiding relationship between clamps 26 and rails 28. In other words, if the mining machine 14 varies in either a transverse or vertical direction a distance greater than the clearance between clamps 26 and rails 28, contact therebetween will result. The maximum distance between the clamps 26 must be less than the overall distance between the rails 28 in order to maintain the guiding relationship between clamps 26 and rails 28 hereinbefore described. At least one roof bolt assembly is within sight of the miner operator as he maneuvers the machine 14 to cut coal and any such contact between clamps 26 and rails 28 can be alleviatedby the operator stopping operations or maneuvering the machine 14. Additional safeguards can be provided to reduce the chance of a contact between clamps 26 and rails 28 causing damage to the machine 14 or assembly 22, for example: a pressure relief valve in the pressure fluid lines between the ceiling jack 30 and floor jack 31 which will open when an excessive amount of pressure is applied to the respective rods 58 and 60, thereby allowing the retraction of one of the rods with an equivalent extension of the other; and springs 116 and 114 at the respective ends of jacks 30 and 31 which allow a movement of such jacks relative to the assembly22.

After the disassociation of assembly 22 from mining machine 14, machine 14 can advance straight forwardly without regard to obstructing a roof bolting operation hereinbelow described. The forward advance of machine 14 from the point of assembly 22 disassociation therefrom is limited by that distance between such point and the end of the V-rail 28 rearward thereof. The time required to mine such distance is normally sufficient to complete a roof bolting operation.

A roof-bolting drill assembly 72 is firmly affixed, in any suitable manner, to panel plate 24 forwardly of jacks 30 and 31. Assembly 72 is of any suitable type known in the art and as shown includes: a drilling tool 74 which is guided at the upper end thereof by a drill-centering guide 76 and is secured at the lower end thereof by a drill chuck 78; a fluid-operated drill motor 80 which rotationally drives tool 74 by supplying power therefrom, through a drill gearbox 82 to the drill chuck 78; and a fluid-operated drill feed cylinder 84 which vertically advances tool 74 during a drilling operation. Another operation accomplished by the roof-bolting drill assembly 72 is the operation of rotating and tightening the roof bolts (such operation being known as wrenching). For further description of the operation and construction of such a roof-bolting drill reference is made to US. Pat. No. 2,741,461.

With such a unit 72, a well-known roof bolting operation is accomplished during the time assembly 22 is disassociated from machine 14 as hereinbefore described. In addition to unit 72, assembly 22 has a well-known timber cylinder 86 affixed thereto inward of tool 74 and in a similar transverse plane therewith. With such a cylinder 86, a roof timber (not shown) may be supported against the passageway roof 62 prior to the drilling period. After the placement of a roof timber the drilling and insertion of a roof bolt can proceed through such timber directly into roof 62.

After the completion of the roof drilling operation the assembly 22 is clamped or associated with the machine 14. To accomplish such association of an assembly 22, hydraulic fluid is supplied to the rod end of jaw clamp cylinder 32 to cause rod 64 to descend downwardly until clamps 26 contact rail 28 an amount sufficient to result in rails 28 being capable of independently supporting assembly 22 while maintaining a sliding relationship between rails 28 and clamps 26. Such a relationship is assured by means of preset jackscrews 88 which extend between hinge means 34. When clamps 26 are sufiiciently secured to rails 28 a pressure-operated sequence valve (not shown), which is of any suitable construction and is positioned in a pressure fluid line extending between the jacks 30 and 31 and jaw clamp cylinder 32, is automatically opened thereby permitting pressure fluid flow to jacks 30 and 31. The flowing pressure fluid causes the pistons 58 and 60 to withdraw, respectively, downward and upward from the roof 62 and floor 16 of the mine passageway. Such a withdrawal of pistons 58 and 60 results in assembly 22 being completely supported on mining machine 14, thereby enabling machine 14 to carry assembly 22 therewith through a forward or rearward movement thereof.

The association of assembly 22 to mining machine 14 as hereinabove described occurs adjacent the rearward end of the rails 28 because of the forward advance of machine 14 with respect to the disassociated assembly 22 during the roof bolting operation thereof. It is possible to make such initial association adjacent the forward endof the machine 14 by moving the machine 14 rearwardly while assembly 22 is disassociated therefrom and then associating assembly 22 to machine 14 when the forward end thereof comes in proximity of assembly 22. Such a rearward movement of mining machine 14 would decrease the operation capabilities of machine 14 therefore assembly 22 of this invention is provided with a traverse drive means for moving an associated assembly 22 from the rearward end of machine 14 forwardly to the forward end thereof without interferring and simultaneously with the forward advance of machine 14.

The traverse drive means may be of any suitable construction and as shown include a traverse drive sprocket which is located intermediate the upper and lower V-rails 28 adjacent the inner side of panel plate 24 and intermediate the rear hinges 40 and 42 and jacks 30 and 31. Sprocket 100 will move assembly 22 axially with respect to machine 14 by means of engagement of the teeth of sprocket 100 with an axially extending traverse chain 92. Chain 92 is located intermediate the upper and lower V-rails 28 adjacent the inner side of panel plate 24 and has the ends thereof secured to suitable chain-connecting means 98, which means 98 are secured to chain anchor posts 94 and 96 which are located, respectively, adjacent the forward and rearward ends of rails 28 and which extend between the upper and lower rails 28 and are firmly secured thereto.

Sprocket 100 is powered in any suitable manner and as shown a fluid-operated motor 102 which has the power output thereof transferred through a suitable gearing arrangement generally indicated at 102, to a drive shaft 104 which rotationally drives sprocket 100. Motor 102 is secured to panel plate 24 at the outer side thereof. Shaft 104 extends transversely of machine 14 through plate 24 to sprocket 100.

To insure proper engagement of teeth of sprocket 100 with the links of chain 92 a well-known idler sprocket 106 is rotatably affixed to the panel plate 22 rearwardly adjacent sprocket 100. With such a well-known arrangement of idler sprocket 106 with drive sprocket 100, proper tooth and link engagement is assured by passing chain 92 under idler sprocket 106 and up and over sprocket 100.

With the traverse drive arrangement hereinabove described an associated assembly 22 can be brought to the forward end of machine 14 from an associated position rearwardly thereof by supplying power from motor 102 which is sufficient to overcome the frictional resistance which exists between the inner surfaces of jaw clamps 26 and the outer surfaces of rails 28 when assembly 22 is in an associated position with respect to machine 14. After overcoming such frictional resistance, assembly 22 will slide forwardly with respect to stationary rails 28, thereby creating wear between the sliding surfaces of clamps 26 and rail 28. To prevent the wear from causing premature failure or replacement of rails 28, wear plates 108 are affixed on the contact surfaces thereof.

Forward and rearward plow plates 100 and 112, respectively, extend diagonally outwardly from panel plate 22 and having the inner ends thereof firmly secured to respective axial ends of plate 22 and have the outer ends thereof form a tieback, in any suitable manner, to plate 22 intermediate the axial ends thereof.

Plow plates

110 and 112 are a desirable integral part of assembly 22 because the forward and rearward advance of machine 14 and assembly 22 might necessitate displacement of mined mineral which has accumulated at the sides of the mined passageway. The diagonal configuration of

plates

110 and 112 will ease the burden of creating such displacement, and will, additionally, protect parts of assembly 22 which would otherwise been exposed to damage from such mined mineral.

A suitable control means is provided which will allow an operator to selectively provide pressure fluid to the traverse motor 102, the sealing and floor jacks 30 and 31, the timber cylinder 86, the drill feed cylinder 84 and the drill motor 80. As shown such control means comprises a control panel 114 secured to plate 24 adjacent the upper rearward end thereof which contains a plurality of independent controls 115 to allow the selective operations hereinabove mentioned. Pressure fluid to panel 114 may be provided from any suitable external source, either a pressure fluid line to assembly 22 from machine 14 or a pressure fluid line to assembly 22 completely independent of machine 14. By having the control panel 14 an integral part of assembly 22 the number of traveling fluid pressure lines can be limited to one.

Although a singular assembly 22 which is associated and disassociated from machine 14 at one side thereof is hereinabove discussed, it is to be understood that the optimum operation of this invention contemplates the use of an assembly 22 being placed on either side of the forwardly advancing mining machine 14 (see FIG. 1).

Some significant functions of this invention are the ability of assembly 22 to disassociate from machine 14 and place a roof bolt in a passageway roof while the machine 14 continues to mine mineral forwardly thereof and the ability of assembly 22 to associate with machine 14 at the rearward end thereof and be traversed from such point of association to the forward end of machine 14. By following the principles taught by this invention, one skilled in the art can achieve the hereinabove mentioned functions with structural alterations to the preferred embodiment hereinbefore described, for example: ceiling and floor jacks 30 and 31, respectively, do not have to be in axial alignment with one another; configurations other than a "V for clamps 26 and rails 28 can be provided; the respective concave and convex surfaces of clamps 26 and rails 28 can be reversed, for example, rails 28 can have concave surfaces which interfit with and partially encompass reciprocal convex surfaces of clamps 26; drill motor 80 can be electronically powered rather than by pressure fluid; timber cylinder 86 can be totally eliminated from assembly 22 if there is no need for timber roof supports; and the like.

The description herein does not limit the structure of this invention and the invention is defined by the scope of the claims set forth hereinafter.

What is claimed is:

l. A roof bolting method comprising: transporting in a given direction by mobile means a drill assembly within an underground passageway with said drill assembly being means, moving said drill assembly in said given direction to selectively reposition said drill assembly with respect to said mobile means.

3. A method as specified in claim 1 including the additional steps'of: during said releasing said drill assembly from said support means, locating said mobile means to maintain limited relative linear and transverse motions between said drill assembly and said support means; and subsequent to said retracting said relatively movable means, moving said drill assembly in said given direction to selectively reposition said drill assembly with respect to said mobile means.

4. A method as specified in claim 3 including the additional step of: during said drilling maintaining said limited relative linear and transverse motions.

5. A method as specified in claim 4 wherein said drill assembly additionally includes selectively extendable and retractable relatively movable timber jack means and comprising the additional steps of: subsequent to said anchoring of said drill assembly and prior to said drilling, anchoring a timber roof support intermediate said roof support and said timber jack means by extending jack means into engagement with said timber roof support and continuing said extending until said timber roof support engages said roof surface and said anchoring is complete; and prior to said moving said drill assembly, retracting said timber jack means until said timber jack means are free from said timber roof support.

6. A method as specified in claim 5 wherein said drilling is in said roof surface above said timber jack support and including the additional step of; subsequent to said drilling and prior to said retracting said timber assembly, securing said timber jack support said roof surface by roof anchoring means extending between said timer assembly and said roof bolt hole.

7. A method as specified in claim 4 including the additional step of: prior to said moving said drill assembly, securing a roof anchoring means in said roof bolt hole.

8. A drilling apparatus comprising: an elongated mobile assembly; at least one drill assembly; cooperable means carried by said drill assembly and said mobile assembly for releasably securing said drill assembly to said mobile assembly; said cooperable means including an elongated portion carried by releasably secured to support means carried by said mobile means during said transporting by selective clamping and unclamping said drill assembly from said support means and with said drill assembly having selective extendable and retractable relatively movable portions; initiating anchoring of said drill assembly between the roof and floor surfaces of said underground passageway by extending said relatively movable portions into engagement with said roof and floor surfaces, respectively; completing said anchoring and substantially simultaneously therewith unclamping said drill assembly from said support means; drilling at least one roof bolt hole above said roof surface; clamping said drill assembly to said support means with limited motion only in said given direction being maintained between said drill assembly and said mobile means; and retracting said relatively movable means until said relatively movable means are free from said roof and floor surfaces.

2. A method as specified in claim 1 including the additional step of: subsequent to said retracting said relatively movable one of said assemblies and a clamping portion carried by the other of said assemblies with said clamping portion being selectively vertically movable into a clamped and unclamped relationship with said support portion; said drill assembly having selectively extendable and retractable anchoring means relatively movable along a vertical axis; and control means carried by at least one said assemblies for selectively actuating said cooperable means and said anchoring means.

9. A drilling apparatus as specified in claim 8 wherein said drill assembly additionally comprises a selectively extensible roof support timber jack.

10. A drilling apparatus as specified in claim 8 with said clamping portion being locatable with respect to said support portion to provide limited relative linear and transverse motions between said clamping portion and said support portion when said clamping portion is in unclamped relationship with said support portion; and limited relativemotion only in the elongated direction of said mobile assembly between the clamping portion and said support portion when said clamping portion is in clamped relationship with said support portion.

11. A drilling apparatus as specified in claim 10 with one of said portions having a pair of continuous vertically concaved oppositely facing surfaces which interfit with and at least partially encompass a pair of continuous vertically convex surfaces on the other of said portions.

12. A drilling apparatus as specified in claim 11 wherein said support portion is fixedly secured to said mobile assembly and said clamping portion is pivotally secured to said drill assembly.

13. A drilling apparatus as specified in claim 12 wherein said concave surfaces are surfaces of said clamping portion and said convex surfaces are surfaces of said support portion.

14. A drilling apparatus as specified in claim 8 additionally including positioning means carried by at least one of said assemblies for selectively positioning said drill assembly with respect to said mobile assembly.

15. A drilling apparatus as specified in claim 14 additionally including control means carried by at least one of said assemblies for selectively actuating said positioning means.

Claims

1. A roof bolting method comprising: transporting in a given direction by mobile means a drill assembly within an underground passageway with said drill assembly being releasably secured to support means carried by said mobile means during said transporting by selective clamping and unclamping said drill assembly from said support means and with said drill assembly having selective extendable and retractable relatively movable portions; initiating anchoring of said drill assembly between the roof and floor surfaces of said underground passageway by extending said relatively movable portions into engagement with said roof and floor surfaces, respectively; completing said anchoring and substantially simultaneously therewith unclamping said drill assembly from said support means; drilling at least one roof bolt hole above said roof surface; clamping said drill assembly to said support means with limited motion only in said given direction being maintained between said drill assembly and said mobile means; and retracting said relatively movable means until said relatively movable means are free from said roof and floor surfaces.

2. A method as specified in claim 1 including the additional step of: subsequent to said retracting said relatively movable means, moving said drill assembly in said given direction to selectively reposition said drill assembly with respect to said mobile means.

3. A method as specified in claim 1 including the additional steps of: during said releasing said drill assembly from said support means, locating said mobile means to maintain limited relative linear and transverse motions between said drill assembly and said support means; and subsequent to said retracting said relatively movable means, moving said drill assembly in said given direction to selectively reposition said drill assembly with respect to said mobile means.

8. A drilling apparatus comprising: an elongated mobile assembly; at least one drill assembly; cooperable means carried by said drill assembly and said mobile assembly for releasably securing said drill assembly to said mobile assembly; said cooperable means including an elongated portion carried by one of said assemblies and a clamping portion carried by the other of said assemblies with said clamping portion being selectively vertically movable into a clamped and unclamped relationship with said support portion; said drill assembly having selectively extendable and retractable anchoring means relatively movable along a vertical axis; and control means carried by at least one said assemblies for selectively actuating said cooperable means and said anchoring means.

10. A drilling apparatus as specified in claim 8 with said clamping portion being locatable with respect to said support portion to provide limited relative linear and transverse motions between said clamping portion and said support portion when said clamping portion is in unclamped relationship with said support portion; and limited relative motion only in the elongated direction of said mobile assembly between the clamping portion and said support portion when said clamping portion is in clamped relationship with said support portion.