US3902324A

US3902324A - Mobile roof supporting shield

Info

Publication number: US3902324A
Application number: US357737A
Authority: US
Inventors: Arthur L Barrett
Original assignee: US Department of the Interior
Current assignee: US Department of the Interior
Priority date: 1973-06-25
Filing date: 1973-06-25
Publication date: 1975-09-02
Anticipated expiration: 1992-09-02

Abstract

A flexible shield protecting excavating activities in a tunnel from roof falls is made mobile by its drivable underlying support structure. Double acting hydraulic jacks, which are retained upright by pivotal and flexible members in each section of a train of sections comprising the support structure, underpin the flexible shield, and are operable to alternately apply the flexible shield in close proximity to the tunnel roof and maintain it free from engagement with the roof to facilitate its displacement along the tunnel with the support structure. A webbing of interlaced straps which take shape within edge supporting cables form panels corresponding to the sections, and these panels are integrated by nonrigid connections at the jack structures to make a canopy arrangement constituting the flexible shield.

Description

United States Patent [191 Barrett Sept. 2, 1975 I MOBILE ROOF SUPPORTING SHIELD Primar Examiner-Dennis L. Ta lor 75 1 t: Ath L.B u,o1 t,V. y Y 1 men or r ur arre ouces er a Attorney, Agenl, or Firm-Gersten Sadowsky; Donald [73] Assignee: The United States of America as R Fraser represented by the Secretary of the Interior, Washington, DC.

' [57] ABSTRACT [22] 'Filed: June 25, 1973 Appl. No.: 357,737

US. Cl 61/45; 61/63 Int. Cl. E2lD 15/44 Field of Search 61/45 D, 45 C, 63; 299/11,

FOREIGN PATENTS OR APPLICATIONS 11/1971 Germany 6l/45 C A flexible shield protecting excavating activities in a tunnel from roof falls is made mobile by its drivable underlying support structure. Double acting hydraulic jacks, which are retained upright by pivotal and flexible members in each section of a train of sections comprising the support structure, underpin the flexible shield, and are operable to alternately apply the flexible shield in close proximity to the tunnel roof and maintain it free from engagement with the roof to facilitate its displacement along the tunnel with the support structure. A webbing of interlaced straps which take shape within edge supporting cables form panels corresponding to the sections, and these panels are integrated by nonrigid connections at the jack structures to make a canopy arrangement constituting the flexible shield.

8 Claims, 8 Drawing Figures PATENTEU SEP 2 I975 SEIZE? MOBILE ROOF SUPPORTING SHIELD The invention relates to apparatus for protecting personnel and equipment from the hazards of roof falls in underground mining operations. More particularly, the invention is in an integrated mobile apparatus in which an elevated flexible shield is adapted to catch the falls of dislodged portions of a mine roof before they reach the subjacent men and machinery.

Protection from roof falls in mine tunnels had heretofore been sought from mobile apparatus which provided roof support rather than shielding from falling roof material. A desired mobility for such roof support apparatus, which allows it to progressively move along with mining machinery advancing the tunnel face, is often made difficult by the rigid roof beams and vertical catenary beams normally used therein to engage the tunnel roof supported thereby. In addition, the great amount of space occupied by such apparatus, due largely to the bulk and size of its support beams, makes them generally unsatisfactory in tunneling operations common to face mining of coal. Apparatus disclosed in US. Pat. No. 2,795,935, granted June 18, 1957, to C. W. Fitzgerald, and US. Pat. No. 2,795,936, granted June 18, 1957, to W. A. Blower et al, are examples of mobile roof supports wherein rigid roof engaging members, such as l-beams, or structural members, are used. Mobility for these patented roof supports is gained by a combination of hydraulically powered, double-acting piston drives of uprightjacks and horizontal ram mechanisms provided for individual units of a total apparatus. Each unit comprises two pairs of the jacks of which the separate jacks of each pair support a beam, extending traversely across the mine tunnel, through pivotal connections between upper piston ends of the jacks and the beam near the extended ends thereof. Jacks of the respective pairs at corresponding ends of the beams are joined through rotatable connections to the ram drive mechanisms which are selectively operable to retract or extend either jack with respect to the other. Consequently, each unit is individually displaceable in either direction along the tunnel path by a walking sequence where after one pair ofjacks is operated to disengage its associated beam from the mine roof, ram mechanisms are operated to drive this pair ofjacks and the beam thereon outwardly from the other pair of jacks whose associated beam had remained engaged with the tunnel roof. Subsequent rcengagement of the beam of the one pair of jacks is followed by a disengagement from the tunnels roof of the beam of the other pair of jacks, and operation of the ram mecha nisms to draw the other pair of jacks and the beam thereon inwardly toward the one set ofjacksv Thereafter this other pair ofjacks is operated to reengage its associated beam with the tunnel roof. Each unit of the apparatus following a previously moved unit is in turn walked by means of the same sequence of operational control being imparted to its pairs of jacks and rams. The less bulky flexible shield arrangement according to at least one embodiment of the present invention is more easily moved along the path ofa mine tunnel with the use of an arrangement of hydraulic jacks and ram mechanisms. However, the propulsion arrangement in this embodiment of the invention is an integral part of the larger apparatus rather than a part of each individual unit of an apparatus. A further embodiment of the invention having a caterpillar type propulsion mechanism for each of its units obtains a still greater maneuverability in a tunnel when such units are cooperatively interrelated with the flexible shield arrangement.

The invention herein features a flexible canopy adapted for application to the: differing segments of the mine tunnel roof encountered as the tunnel face is advanced by the mining activity over which this canopy is maintained, and a support structure for the canopy which allows an extensive contact between the canopy and the mine roof in spite of the irregularities of the roof surface. Maintaining the: canopy as indicated is a propulsion means which in effectuating movement of the canopy through the mine tunnel is capable of displacing the canopy so as to vary it in width, as well as rectilinearly and angularly. 'Clharacterizing this propulsion means are elongated front and back end sections,

each of which has operatively connected therewith, at inner ends thereof, a relatively shorter articulated driver section, and a selectively controlled power generating section operatively connected between the inner ends of the respective driver sections. The several sections are essentially quadrangular in form in that each section is defined by upright extensible hydraulic jacks in four corners thereof. However, each of the driver sections takes its form from a pair of jacks at the inner end of the adjacent end section, and two jacks of the power section adjacent thereto. Vertical stability for this sectional arrangement is maintained by cross brace structures extending between each pair of the upright jacks aligned in cross-sectional planes of the tunnel, and further bracing elements extending between each set of two jacks in the respective end sections which stand adjacent the same side wall of the tunnel. Extensible, double-acting hydraulic ram devices are horizontally disposed in the driver sections by flexible connections to adjacent jacksaligned with the side walls of the tunnel. Each side of the power section is provided with an elongated, narrow platform, maintained horizontally by pivotal connections to the power section jacks adjacent thereto, on which are affixed a hydraulic oil tank, pump and motor, and a panel of controls for valves which determine the operation of various jacks and ram drive devices of the apparatus. Each jack has an upper linearly displaceable and rotatable piston part to whose outer extended end is pivoted a laterally extending, relatively short horizontal beam. Affixed to the upper surface of each of these beams, near the extended ends thereof, are short posts having superposed thereon roof engaging areas such as a knobbed pad or a pointed conical head. Suspended from this multiplicity of posts on the horizontal beams are several panels of flexible webbing constituting the overhead canopy of the apparatus. The further embodiment of the invention has a yet simpler construction wherein individual linearly displaceable and rotatable jacks are mounted fore and aft to its caterpillar propulsion mechanism by means of flexible and pivotal connections. The flexible canopy construction, and the generally flexible mobile support structure provided therefor in each embodiment, allow an apparatus according to the present invention to have complete utility in tunnels of differing sizes and shapes.

It is therefore an object of the present invention to provide a mobile roof shield under which men and machines perform mining operations without hazard from falling roof material.

A further objective of the present invention is to provide a generally flexible mobile shield against mine roof falls which is accommodative to a diversity of mine tunnel configurations.

These and other objects and advantages of the present invention will become more fully apparent from the following detailed description of the invention set forth herein and from the accompanying drawings made a part hereof in which:

FIG. 1 is a partially schematic side elevational view of the overall apparatus according to one embodiment of the present invention;

FIG. 2 is a plan view of a fragmentary showing of the apparatus as shown in FIG. 1;

FIG. 3 is an end view, taken along line 3-3 in FIG. 1, showing cross connections between opposite sides of the apparatus;

FIG. 4 is a fragmentary showing, partly in section, of a spiked post in the canopy supporting structure;

FIGS. 5 and 6 are fragmentary showings of the canopy and structural support elements therefor; and

FIGS. 7 and 8 are partially schematic side and end elevational views of fragmentary showings of a second embodiment of the present invention.

With reference to FIGS. 1 to 3, the apparatus according to the present invention is disclosed therein as serving to protect against roof falls over a mining activity in a tunnel 8 being cut in substances such as stratums of coal. In use this apparatus maintains a protective shielding in the form of a canopy 10 contiguous to tunnel roof 12 when the apparatus is held stationed between

side walls

14 and 16 of the tunnel, by parts thereof placed securely in contact with the tunnels floor 16 and its roof, following periodic displacements of the apparatus to keep up with the mining activity. The larger structural components of the apparatus may be viewed, for the purposes of the present explanation, as including in combination a front end section 20, a back end section 22, and a power generating and control section 24 interconnected to the front and back end sections by a front driver section 26 and a back driver section 28, respectively. Section is effectively an activatable rectilinear framework having as a superstructure thereon a flexible panel characterized by its mesh of relatively wide webbing. Comprising this framework are four double-acting hydraulic jacks, including

jacks

30, 32 and 34 visible in FIGS. 1 and 3, which effectively constitute corner posts of the generally rectangular structure of section 20 wherein these jacks are maintained upright by interconnections with a combination of rigid, extensible and flexible beams. Thus, on the side of this structure adjacent tunnel wall 12, jacks and 32 obtain support from a rigid horizontal beam 36 pivotally connected to heavy duty, relatively

wide bands

38 and 40 affixed to the respective jacks adjacent to the lower parts thereof, and extensible horizontal beam 42 pivotally connected to corresponding bands 44 and 46 affixed to the respective jacks adjacent to the upper parts thereof, and a rigid beam 48 disposed diagonally between

beams

36 and 42, in the plane thereof, by pivotal connections to the respective outer

cylindrical housings

50 and 52

ofjacks

30 and 32. The further two jacks of section 20, includingjack 34, on the side thereof adjacent tunnel wall 14, are also maintained upright with the assistance ofa support therefor wherein upper and lower horizontal beams and a diagonal beam are interconnected with these jacks by pivotal connections which are the counterparts of those heretofore described for the aforesaid one side of the section. The respective upper horizontal beams of the structures side supports are rendered extensible by relatively stiff spring coupling devices therein such as that represented by device 54 in beam 42 whose pivotal connections to

jacks

30 and 32 are made from the enclosure housing of device 54 and the extended end of a piston member coupled to the housing by the spring enclosed therein.

Lateral support for the structure of section 20 is achieved with flexible composite members which extend between the jacks correspondingly situated on the opposite sides of the structure. As most clearly appears in FIG. 3, front end jack 32 and jack 34, its front end counterpart adjacent side wall 14 of the tunnel, are tied together by a composite cross beam 56. Comprising beam 56 are a centrally situated box girder 58, and elongated multiple leaf springs constituting

flexible members

60 and 62 which are combined with the girder to form an arched span over the forward workin g area of section 20. More specifically, end portions of the respective leaf spring members have a set therein with respect to a long central portion thereof, which facilitates the attachments separately of such end portions within the respective end openings in girder 58 and channel-

like clamp devices

64 and 66 fitted to the outer cylindrical housings of

jacks

32 and 34, respectively. In the same way jack 30 and the jack corresponding thereto on the opposite side of the structure, are tied together by a composite cross beam comprising symmetrically arranged leaf spring members which by attachments to the respective jacks and a box girder form the structure extending between the jacks which spans across the working area in the tunnel at the rear of section 20.

The four jacks constituting section 20, and the other upright jacks of the apparatus herein, are all conventional double acting hydraulic powered prop structures of the type more fully described in the previously identified patent to Blower et al. Each such jack stands on a floor engaging foot or pad 68 thereof having a shallow convexity which allows the jack to participate in a minor degree of roll on irregular surfaces of tunnel floor 16. The floor pads are affixed beneath cylindrical outer shells of the jacks, such as housings and 52 of

jacks

30 and 32, respectively, which enclose a hydraulic cylinder wherein a piston is reciprocable for vertically displacing a piston rod. Thus, jacks 30, 32, and 34 are equipped with

upright piston rods

70, 72, and 74, respectively. Pivotally supported at the upper ends of

piston rods

70, 72, and 74, are relatively short, laterally extending, or cross channel beams 76, 78, and 80, respectively. The pivotal connections are made in an obvious manner by pivot pins, which are journaled in holes extending horizontally through upper end portions of the piston rods, engaging holes at mid-points in the opposite flanges of the channel beams. Thejack laterally opposite to jack 30 in section 20, as well as the other jacks of the further sections of the apparatus, each have provisions therein for a hydraulic cylinder in which a piston together with the rod thereof are reciprocable. To each of the respective end portions of the further piston rods is pivotally mounted a laterally extending channel or cross beam in the manner heretofore described for the jacks of section 20. Accordingly, further jacks 82, 84, 86 and 88, which are visible in FIG. l, are equipped with

piston rods

90, 92, 94 and 96, respectively, on which are pivotally mounted channel or cross

beams

98, 100, 102 and 104, respectively.

Referring particularly to FIGS. 1,3 and 4, it will be seen that each of cross beams 78'and 81) have affixed to their outer back surfaces, at a short distance from each of the respective extended ends thereof, a spiked post. Cross beams 76, 98, 100, I02, and 104, which are visible in FIG. 1, and the croresponding cross beams laterally spaced'from each of those indicated such that they are adjacent tunnel wall 14, each also have similarly affixed thereto a spaced pair of spiked posts.

Posts

110 and 112 affixed to cross beam 78, and

posts

114 and 116 affixed to cross beam 80, as well as each of the posts affixed to the other cross beams of the apparatus, have a configuration which more fully appears in the showing of FIG. 4 where post 110 is seen as comprising a reduced cylindrical mid-section 118 surmounted by a conical spike 120. Reference to FIGS. 2 and 4 to 6, show these spiked posts as constituting means for mounting canopy upon the'respective sections of the apparatus. As was hereinbefore indicated with respect to section of the apparatus, canopy10 is made up of individual panels of meshed webbing. Nylon straps serve as webbing in the presently disclosed embodiment,although the use of other strap or sheet materials of adequate strength, such as metal straps, would be satisfactory; Steel cables are used to support the webbing along the four edges of each panel, and two additional steel cables are provided to lend support at intermediate points on the panel. Thus, an interlaced webbing of straps 130 forming a mesh constitutes the shielding of a panel 132 operative in section 20.

Maintaining the shape of panel 132 are its opposite

end support cables

134 and 136, and its opposite

side support cables

138 and 140, having their respective extremities attached to generally oval links which are fitted upon the several posts of the four channel

beams including beams

76, 78, 80, and the beam adjacent tun nel wall 14, laterally opposite to beam 76. An additional supporting cable 142 tied to links fitted upon

posts

144 and 112 of the facing cross beams 76 and 78, respectively, is interlaced in the webbing of panel 132. Further support is provided by a cable, not shown, which threads through panel 132 between attachments thereof to links fitted upon post 114 and the post opposite thereto on the beam facing beam 80.

Posts

144 and 146, which are affixed to cross beam 76, appear in FIG. 5 as providing means for appropriately retaining a portion of end cable 134 in panel supporting position. It should be evident from the showing in FIGS. 4 and S that the attachment links are easily fitted to their posts by lowering a wider end opening of the link over the posts conical spike and down to the reduced midsection thereof, and thereafter shifting the link with respect to the post such that a narrower end opening of the link engages the posts mid-section whereat it is locked under a flanged portion of the spike. The posts mid-section is of sufficient height to thusly accommodate two links. Accordingly, a link 148, fitted to post 144, facilitates the attachment thereto of segments of cable 134 and cable 142, and a further link 150, fitted to post 146, facilitates the attachment thereto of an end segment of cable 134 and side support cable 138. Attachments of the cables to the links are made as shown, by way of example, in FIG. 6, where link 148 is seen as carrying a thimble sleeve 152about which is wrapped a length of cable 134, and clip type clamps 154 and 156 are applied and secured in a conventional manner to bind together overlapping portions of the cable. The straps ofzmesh 130, such as strap 158 appearing in FIGS. 5 and 6, are appropriately overlapped and sewn at their extremities to provide suitable loops through which the cables are caused to extend in an obvious manner. Straps dependent from central portions of their support cables are maintained suitably separated by spacer sleeves riding on the cables; as for example spacers 160 shown in FIG. 5. As'is indicated in the showing of FIG. 5, the straps of panel 130 are of such length and distribution thereon that the edges of the panel may assume a curved contour. These edges are so shaped to fit uniformly and in close proximity to a complementary contour given to the edges of an adjacent panel, to be hereinafter more fully described, when the several panels are assembled to form canopy 10 as an integral shield. The: respective cross beams, from which the panels are dependent, take requisite angular or skewed dispositions in the approximate plane of the canopy, allowed by the rotatability of the pistons in the supporting jacks, to accommodate the curved forms of the supporting cables of the complementary shaped panels.

Sections

22 and 24 of the apparatus have operationally associated therewith further mesh panels and l72,'respectively, which in their form and structure are identical'to panel 132 previously disclosed for section 20; As should be evident from the foregoing, the

respective sections

22 and 24 are each equipped with eight spiked posts having fittedthereto the requisite oval links which facilitate the attachments of the cables giving form to panels 170 and 172. However,

sections

26 and 28 of the apparatus have operatively associated therewith-intermediate panels and 182, respectively,'which, as will be seen by reference to FIGS. 1 and 2, are substantially shorter than the panels previously described, although they are coextensive in length with those panels. Moreover, as was previously indicated,

straps comprising panels

180 and 182 are of such length and distribution thereon that the longer edges of the panels are contoured to match adjacent complementary edges of the larger panels. Further,

panels

180 and 182 are equipped in the manner of the larger panels in that each includes a requisite number of oval links which faciliate the attachment of panel forming cables. On the other hand, the links of

panels

180 and 182 share the spiked posts of the sections adjacent thereto. More specifically, the links of panel 180 are locked under the spikes of posts in

sections

20 and 24 where they are effectively maintained, as illustrated in FIG. 5 by

exemplary links

184 and 186, on the posts affixed to cross

beams

76 and 98, and the corresponding cross beams laterally spaced from these beams and adjacent to tunnel'wall 14. Links of panel 182 are similarly effective when maintained on posts affixed to cross beams 100 and 102 on

jacks

84 and 86, respectively, and cross beams on jacks laterally spaced therefrom in

sections

24 and 22.

Driver sections 26and 28 of the apparatus are each characterized by controllable arrangements therein having a cooperative interaction with the jacks in the adjacent sections which are contiguous thereto. Thus, an arrangement at each side of a driver section includes a pair of horizontal extensible linkages articulately connected to the aforesaid contiguous jacks at each side of the section. The linkages of each such pair are respectively connected to upper and lower bands affixed to the jacks, as is exemplified by the illustration in FIG. 1 with respect to one side of section 26 where a lower linkage 190 is connected between band 38 affixed to jack 50 and a similar band 192 affixed to jack 82, and an upper linkage 94 is connected between bands 44 and 196 to jacks50 and 82, respectively. The length of linkage 190 is determined by the operation of a doubleacting, hydraulic thrust ram 198 having piston and cylinder elements constituting an integral part of the linkage in a conventional manner. Linkage 190 is afforded a multidirectional limited angle swing with respect to

bands

38 and 192 by universal couplings, such as is represented at

junctures

200 and 202 connecting the linkage to the bands. Correspondingly, linkage 194 of section 26, and linkage 204 and 2060f section 208 have as an integral part thereof double-acting hydraulic thrust rams 208, 210, and 212, respectively. and the junctures of these linkages with bands affixed to the jacks operatively associated therewith are by way of universal couplings of the type hereinaboove indicated for linkage 190. As is now evident from the foregoing each linkage of the further linkage pairs of the side of the respective driver sections which is opposite to that appearing in FIG. 1, has as an integral part thereof a double-acting, hydraulic thrust ram, and is connected to jacks operatively associated therewith by way of universal couplings at bands affixed to these jacks.

The generation of hydraulic power and a control of this power for a selective application thereof to the multiple jack and thrust ram arrangements comprising the motive means of the apparatus disclosed herein, are effectuated in the centrally situated power section 24. Each side of the apparatus is served by a separate power and control unit of section 24, although a single unit of appropriate power generating capacity and control facilities may also have utility in the apparatus. In FIG. 1, a power unit 220, which appears as exemplary herein, is shown maintained suspended between

jacks

82 and 84 by four pivotal connections from vertical side supports 222 and 224 of the unit, to the previously mentioned upper and lower bands affixed to the jacks. To the bed of a platform 226, made integral with the side supports at the lower parts thereof, is secured a hydraulic oil supply tank 228, and mounted above the tank is a hydraulic pump and motor mechanism 230. lnterconnecting the twelve jacks and eight thrust rams of the apparatus as disclosed herein, with oil supply 228 and motor driven pump mechanism 230, are conventional flexible hydraulic hoses and couplings, not shown, and a suitable hydraulic control system of a type well known in the related art which is exemplified by the control system disclosed in the previously identified patent to Fitzgerald. The various hydraulic components of this system, including its multiplicity of bidirectional valve control boxes respectively connected to each of the jacks and thrust rams, are conveniently grouped and mounted under a control console, displaying the operating handles of such valve boxes, which is attached to platform 226 of power section 24.

Advanced of the apparatus disclosed herein along a direct path following the longitudinal axis of the tunnel towards its face 240 is accomplished by propulsion of its integral structure in a step-wise operation wherein the jacks and thrust rams thereof are manipulated in the manner hereinafter set forth. Starting with the apparatus fully extended wherein the four thrust rams in each

driver sections

26 and 28 are extended as shown by the condition of thrust rams 198 and 208 in

linkage

190 and 194, and all twelve jacks are extended so as to apply their pads 68 firmly in contact with tunnel floor 16, and engage their control spikes firmly in tunnel roof l8, wherefore all panels of canopy 10 are supported in close proximity to the tunnel roof, the operation is initiated with the pistons of the four jacks of back end section 22 being retracted to take their conical spikes out of contact with tunnel roof 18 so as to withdraw panel away from the roof. Secondly, the four thrust rams, including thrust rams 210 and 212, of the back end driver section 28 are operated to retract the four linkages thereof, including

linkages

204 and 206, so as to advance section 22 toward all the other structures of the apparatus then firmly held by the extended jacks thereof. Thirdly, pistons of the four jacks of back end section 22 are extended to again firmly secure this section between the floor and roof of the tunnel. in this state of apparatus, intermediate panel 182 is relaxed, and sags as shown in FIG. I. Fourthly, pistons of the fourjacks of power section 24 are retracted to free this section for displacement, wherefore panel 172 is withdrawn from the tunnel roof. Fifthly, the four thrust rams of front end drive section 26 are operated to retract the four linkages thereof, including

linkages

190 and 194, concurrently with the operation of the thrust rams of section 28 to extend the four linkages thereof, so as to move section 24 the distance of a linkage change with respect to

sections

20 and 22 which are then firmly fixed between the floor and roof of the tunnel. Sixthly, pistons of the four jacks of power section 24 are extended to again firmly secure this section between the floor and roof of the tunnel. in this state of the apparatus, intermediate panel is relaxed, and sags. Seventhly, pistons of the four jacks of front end section 20 are retracted to free this section for displacement wherefore panel I32 is withdrawn from the tunnel roof. Eightly, the four thrust rams of front end driver section 26 are operated to extend their linkages so as to advance front end section 20 with respect to

sections

22 and 24 which are then firmly fixed between the floor and roof of the tunnel. Thus, the entire apparatus has moved to displace canopy 10 ahead by the length of the motion given the thrust ram linkages. During any displacement occurring in the operation, two out of the three sections which comprise four jacks are maintained secured between the floor and roof of the tunnel.

The apparatus herein is also susceptible of a wide range of other motions. in one instance, all of the upright jacks at one side of the tunnel are maintained secured by engagement of their pads and spikes with the floor and roof of the tunnel, and the step-wise operation previously set forth is applied only to the jacks at the other side of the tunnel. As a result, canopy 10 is displaced into a paralleogram-like element and its net width is reduced. In this manner, the width of canopy 10 can be reduced by approximately 30 percent to ad just to variations in room width. Further, by alternate side operations of this nature, canopy 10 can be moved in a direction to the right or left of the tunnel center line as desired. Moreover, a turn may be negotiated if one of the rear jacks of the front end section is left engaged with the floor and roof of the tunnel, and if that corner or any other corner of that section is locked to retain the section rectangular. Consequently, where the thrust rams on the side opposite the engaged jack is advanced, the section will turn about the engaged jack as a center, and a turn is thus started in a direction which may be perpetuated by handling the following fourjack sections in the same manner as they reach the point of turning. It should now be evident that a wide range of other motions may be practiced with the apparatus by appropriate management of the roof-engaging jacks and the thrust rams. In the event it is desired to set roof bolts through any portion of the panels composing canopy 10, a pair of cross straps in such panel which are at right angles to each other can be left out in any position where an opening is required. The opening thus provided will permit bolt holes to be drilled and roof bolts to be installed.

In the further embodiment of the present invention illustrated in FIGS. 7 and 8, each section of a multisection arrangement therein includes a pair of caterpillar drive assemblies as integral parts thereof which serve in place of the drive sections applicable to the embodiment of the invention previously described. One side of a section comprising this further embodiment appears in FIG. 7 where a caterpillar drive assembly 300 is shown as having flexibly mounted to each of its extended ends as extensible upright jack mechanism comprising a double-acting hydraulic piston device at the lower and upper ends thereof, respectively. Jack mechanism 302, which is adapted to function at one end of assembly 300, includes a tubular housing 304 wherein a cylindrical enclosure 306, affixed in the housing by conventional ring brackets. has operable therein a lower piston device represented in FIG. 7 by its piston rod 308, and an upper piston device represented in the figure by its piston rod 310. An explanation in greater detail of this conventional structural arrangement of dual piston devices in a jack mechanism is available by reference to the disclosure of the previously identified patent to Fitzgerald. Upper piston rod 310 supports by pivotal attachment thereto a relatively short cross beam 312 on which spiked posts, including post 314 visible in FIGv 7, are affixed at spaced points thereon, as was previously explained with respect to the first embodiment of the present invention. Lower piston rod 310 has pivotally connected thereto a foot element or pad 316 which is adapted to rest on tunnel floor 16 when rod 310 is in its extended position. Integrally formed on tubular housing 304 are a pair of spaced, circular flanges 318 and 320 which are radially disposed a short distance below a central circumference of the housing. These flanges are enclosed within a bearing box having the form of a relatively thick collar 322 loosely fitted on the tubular housing. More specifically, collar 322 has upper and lower

central openings

324 and 326, respectively, through which tubular housing 304 projects and is positioned where flanges 318 and 320 reside contiguous to radially disposed internal surfaces of the collar. However, flanges 318 and 320 are free to move with respect to the internal surfaces of collar 322 such that housing 304 is rotatable in

collar openings

324 and 326.

Attachment of jack mechanism 302 to drive assembly 300 is facilitated by a spring-held pivotal connection 330 providing a flexible restraint which maintains the jack mechanism in an upright position a short dis tance from one end of the drive assembly. Spaced extension arms of connection 330, including arm 332 visible in FIG. 7. which are bolted to the curved surface of collar 322, are further pivotally supported on a double ear bracket, including car 334 visible in FIG. 7, of the connection. In turn, the connection bracket is bolted to one end portion of a deck plate 336 of drive assembly 300. Constraining the aforesaid pivotal attachment as shown in FIG. 7, is a substantially arcuate, stiff leaf spring structure 338 affixed by retainer plates and bolts to collar 322 between the aforesaid extension arms, and to deck plate 336 between the bracket ears affixed to the deck. The other end of drive assembly 300 is correspondingly equipped with a spring-held pivotal connection 340 which is effective to flexibly restrain a jack mechanism 342 upright at a short distance from the drive assembly. Moreover, as should be evident from the showing in FIG. 7,jack mechanism 342 and pivotal connection 340 provided therefor; correspond in all particulars to the form and detail of jack mechanism 302 and its pivotal connection 330.

Drive assembly 300 is, in essence, a conventional hydraulically powered catcpillar motive means now well known in the art. Comprising this assembly is a caterpillar chassis 350 wherein are operable cogged wheels within a roller belt, and to which is mounted deck 336. Further arranged on deck 336 are an electric motor driven hydraulic pump 352, an oil reservoir 354, and a hydraulically driven motor 356 which impels the roller belt construction by way of a belt drive as shown in FIG. 7. Jack housing 302 and the respective correspondingly constructed jack housing which is laterally spaced therefrom on the other side of tunnel 8, are flexibly interconnected by a spring beam structure of a form which more fully appears in the showing of FIG. 3 by lateral beam 58. Reference to FIG. 8 reveals a leaf spring component 360 of the laterally interconnecting beam which extends to jack mechanism 342 whereat the component is affixed to a housing 362 of the jack mechanism by a bolted clamp device 364. Lower and upper piston rods 366 and 378, respectively, of the hydraulic piston enclosed in housing 362, are shown in FIG. 8 in their extended condition where a cross beam 370, pivotally connected at the extendedend of piston rod 368, thrusts spiked post 372, affixed to one end of the beam, and its counterpart spiked post, affixed to the other end of the beam, into roof 18 of the tunnel, and piston rod 366 firmly plants a pad 374, pivotally connected to the extended end thereof, on floor 16 of the tunnel. Now believed to be evident from the foregoing is that

beams

312 and 372, provide four spiked posts, including

posts

314 and 372, for cooperation with the other generally quadrangular arrangements of spike posts above pairs ofjack mechanisms, individually associated with a caterpillar drive unit, which are laterally and longitudinally spaced from

jack mechanisms

302 and 342, to support a canopy 380 which corresponds to all particulars to the form and details of construction and mounting ascribed to canopy 10 of the embodiment of the present invention first described. More particularly, canopy 380 includes longer panels, such as panel 382 shown in FIG. 7, which are individually supported and positioned by four jack mechanisms associated with each of the several sections, and shorter intermediate panels which are individually supported and positioned by fourjack mechanisms comprising the neighboringjacks of adjacent sections which are normally spaced one from the other by the length of a shorter panel.

Maneuvering of any mobile portion of the FIGS. 7 and 8 embodiment requires that its canopy 380 be lowered and its

pads

316 and 374, be raised, as indicated in the showing of FIG. 7. The bearing collars for the jack mechanisms, such as collar 322, provides angular vertical support so that a highly effective horizontal support is available in the plane of the canopy which obtains protection from roof falls even when the jack mechanisms are not engaged between the roof and floor of the tunnel, and stability of the overall apparatus as it travels and maneuvers about the tunnel. Moreover, since no great vertical or horizontal loads are normally carried by the caterpillar drive assemblies, the weight and strength of these assemblies can be greatly reduced so as to provide a lighter, more maneuverable caterpillar and support structure of a reduced cross section, and thus provide a maximum clearance around men and machines in the tunnel. In case of a roof fall during a moving operation, the tubular housings of the jack mechanisms are capable of moving with respect to the caterpillar drive assembly thereof by virtue of the mounting springs and the pivotal mounting associated therewith connecting the bearing collar to the drive assembly. In case of an unusually heavy load, spiked posts and a pad of a jack mechanism can be forced into engagement with the tunnels roof and floor without passing any unduly heavy load to the drive assembly. Separate control of the hydraulic power to each section or part thereof is contemplated, although the requisite operator controls are normally situated at a central point or points on the aperture. Selective operation of the caterpillar drive assemblies with predetermined jack mechanisms being engaged with the tunnels roof and floor, permits complete steerability of the apparatus within the horizontal plane, including changing width of canopy 380, and turning it through angle or around corners, by following procedures like those previously explained in connection with the embodiment of FIGS. 1 to 6. In any case, the opposite side units, or complete sections of the apparatus are operable singly, in pairs, all at one time, or in any other selected manner, to provide the desired mobility.

Further reasonable variations and modifications are possible within the scope of the foregoing disclosure and the appended claims to the invention.

I claim:

1. Manipulated apparatus for protection against the hazards of roof falls in underground tunnels which is operatively responsive to a selectively controlled power means comprising a flexible shielding means, and

a mobile mechanism having operable therein a plurality of reciprocable and pivotable devices, and means, activatable by said controlled power means, to propel said mechanism with respect to said tunnel, said devices including elements, activatable by said controlled power means, to displace components affixed in a predetermined spatial arrangement thereon between first and second dispositions with respect to said tunnel, said components having said shielding means depend therefrom and are effective by activation of said elements which displaces said components from said first to said second disposition thereof to maintain said shielding means in close proximity to a roof of said tunnel, and by activation of said elements which displaces said components from said second to said first disposition thereof to maintain said shielding means free from engagement with said roof, and said propelling means being adapted for operation upon activation thereof when said components are in said first disposition thereof.

2. The apparatus of claim 1, wherein said plurality of devices includes jacks having reciprocable and rotatable pistons, and cross beams pivotally mounted on said pistons and displaceable therewith, and said components comprise posts surmounted by pointed parts whereby said posts serve to facilitate nonrigid connections between said shielding means and said beams, and said pointed parts serve to maintain said shielding means in close proximity to said tunnel roof by engagement with said roof.

3. The apparatus of claim 2 wherein said nonrigid connections include substantially oval rings having a relatively wide end opening which facilitates depositing said rings upon said posts and fixing said shielding means to said rings, and a relatively narrow end opening which facilitates securing said ring to said post.

4. The apparatus of claim 2 wherein said mobile mechanism comprises a plurality of sections, and said plurality of devices includes as a part thereof arrangements of jacks associated with said sections, each said jack having at least one reciprocable and rotatable piston operable therein, and said shielding means comprises a plurality of panels of which each panel is operatively associated with a predetermined one of said plurality of sections, whereby said nonrigid connections maintain each said panel over said section associated therewith. 7

5. The apparatus of claim 4, wherein each panel is generally quadrangular in shape, and includes shape defining cables extending along the respective edges of said panel, flexible webbing straps supported on said cables by retaining said cables in loops of said straps formed at the extremities thereof, said straps being in terlaced in a generally loose mesh pattern, and said nonrigid connections including coupling rings which engage said posts of said components and have end portions of said cables secured thereto.

6. The apparatus of claim 5 wherein predetermined opposite edges of alternate panels of said shielding means have a curved shape, and alternate panels between said predetermined edges have edges opposite to said predetermined edges whereby a generally uniform close spacing between said panels is achieved.

7. The apparatus of claim I wherein said mobile mechanism comprises a plurality of displaceable sections including a front end section, a back end section, a central section, and intermediate sections interconnecting said central section with said front and back end sections, each of said sections having as parts thereof first and second side units, each said side unit of said end and central being part of said activatable elements including a pair of spaced jacks, a plurality of support members extending between said jacks and pivotally connected thereto, corresponding jacks of said first and second units of each said end and central sections being interconnected by a flexible beam, whereby said support members and said flexible beam maintain said jacks in a generally upright disposition, each said side unit of said intermediate sections being part of said means to propel including a pair of doubleacting extensible thrust rams which are operably responsive to activation thereof by said controlled power means, said thrust rams of each said pair being spaced where they are separately operable by way of universal connections between a different one of said jacks of said central section and a jack closest thereto in one of said end section side units, whereby said thrust ram when activated functions alternately to draw said jacks connected thereto a predetermined distance toward one another, and to spread said jacks connected thereto said predetermined distance away from each other, said central section having in each side unit, as an integral part thereof, a platform structure whereon said selectively controlled power means is disposed for operation, and means attached to upper extensible parts of said jacks of said apparatus whereon said components are spatially arranged and whereby said shielding means is maintained dependent therefrom so as to extend over all said sections of said apparatus.

8. The apparatus of claim 1 wherein said mobile mechanism comprises a plurality of displaceable sections, each said section having first and second side units, each said side unit comprising first and second portions constituting parts of said activatable elements and said means to propel, respectively, said first portion including a pair of jack structures, each said structure having an upper and a lower double-acting extensible means and a cylindrical housing containing said extensible means such that an extension of said upper extensible means is displaceable through an upper opening of said housing and an extension of said lower extensible means is displaceable through a lower opening of said housing, said extensible means being activatable in response to said selectively controlled power means to alternately project and retract said displaceable extensions thereof with respect to said housing and the openings therein, spaced radial extensions made integral with said housing at spaced outer surfaces thereof,

a bearing support collar in which said radial extensions are substantially enclosed and in sliding contact with internal surfaces of said collar whereby said housing with said extensible means therein are rotatable with respect to said collar, and said second portion including a caterpillar'tractor means assembly having means affixed to a deck of said tractor which constitutes part of said selectively controlled power means, and a drive to said tractor means in response to activation thereof by said selectively controlled power means, separate pivotal means attached to said tractor deck .at opposite ends thereof, each pivotal means having a segment thereof outwardly disposed beyond the end of said tractor deck related thereto, each said segment having affixed thereto one of said jack structures by attachment to said bearing support collar provided therefor, a substantially curved leaf spring associated with each pivotal means, such that each said jack structure is further attached to said deck by said leaf spring, corresponding jack structures of said first and second units of each said sections being interconnected by a flexible beam having extended ends thereof affixed to said cylindrical housings of said interconnected jack structures, whereby said pivotal means and said leaf spring associated therewith, and said flexible beam maintain said jacks in a generally upright disposition, a foot pad means pivotally connected to the end of said extension of each of said lower extensible means, and means pivotally connected to the end of said extension of said upper extensible means whereon said components are spatially arranged and whereby said shielding means is maintained dependent therefrom so as to extend over all said sections of said apparatus.

Claims

1. Manipulated apparatus for protection against the hazards of roof falls in underground tunnels which is operatively responsive to a selectively controlled power means comprising a flexible shielding means, and a mobile mechanism having operable therein a plurality of reciprocable and pivotable devices, and means, activatable by said controlled power means, to propel said mechanism with respect to said tunnel, said devices including elements, activatable by said controlled power means, to displace components affixed in a predetermined spatial arrangement thereon bEtween first and second dispositions with respect to said tunnel, said components having said shielding means depend therefrom and are effective by activation of said elements which displaces said components from said first to said second disposition thereof to maintain said shielding means in close proximity to a roof of said tunnel, and by activation of said elements which displaces said components from said second to said first disposition thereof to maintain said shielding means free from engagement with said roof, and said propelling means being adapted for operation upon activation thereof when said components are in said first disposition thereof.

4. The apparatus of claim 2 wherein said mobile mechanism comprises a plurality of sections, and said plurality of devices includes as a part thereof arrangements of jacks associated with said sections, each said jack having at least one reciprocable and rotatable piston operable therein, and said shielding means comprises a plurality of panels of which each panel is operatively associated with a predetermined one of said plurality of sections, whereby said nonrigid connections maintain each said panel over said section associated therewith.

5. The apparatus of claim 4, wherein each panel is generally quadrangular in shape, and includes shape defining cables extending along the respective edges of said panel, flexible webbing straps supported on said cables by retaining said cables in loops of said straps formed at the extremities thereof, said straps being interlaced in a generally loose mesh pattern, and said nonrigid connections including coupling rings which engage said posts of said components and have end portions of said cables secured thereto.

7. The apparatus of claim 1 wherein said mobile mechanism comprises a plurality of displaceable sections including a front end section, a back end section, a central section, and intermediate sections interconnecting said central section with said front and back end sections, each of said sections having as parts thereof first and second side units, each said side unit of said end and central being part of said activatable elements including a pair of spaced jacks, a plurality of support members extending between said jacks and pivotally connected thereto, corresponding jacks of said first and second units of each said end and central sections being interconnected by a flexible beam, whereby said support members and said flexible beam maintain said jacks in a generally upright disposition, each said side unit of said intermediate sections being part of said means to propel including a pair of double-acting extensible thrust rams which are operably responsive to activation thereof by said controlled power means, said thrust rams of each said pair being spaced where they are separately operable by way of universal connections between a different one of said jacks Of said central section and a jack closest thereto in one of said end section side units, whereby said thrust ram when activated functions alternately to draw said jacks connected thereto a predetermined distance toward one another, and to spread said jacks connected thereto said predetermined distance away from each other, said central section having in each side unit, as an integral part thereof, a platform structure whereon said selectively controlled power means is disposed for operation, and means attached to upper extensible parts of said jacks of said apparatus whereon said components are spatially arranged and whereby said shielding means is maintained dependent therefrom so as to extend over all said sections of said apparatus.

8. The apparatus of claim 1 wherein said mobile mechanism comprises a plurality of displaceable sections, each said section having first and second side units, each said side unit comprising first and second portions constituting parts of said activatable elements and said means to propel, respectively, said first portion including a pair of jack structures, each said structure having an upper and a lower double-acting extensible means and a cylindrical housing containing said extensible means such that an extension of said upper extensible means is displaceable through an upper opening of said housing and an extension of said lower extensible means is displaceable through a lower opening of said housing, said extensible means being activatable in response to said selectively controlled power means to alternately project and retract said displaceable extensions thereof with respect to said housing and the openings therein, spaced radial extensions made integral with said housing at spaced outer surfaces thereof, a bearing support collar in which said radial extensions are substantially enclosed and in sliding contact with internal surfaces of said collar whereby said housing with said extensible means therein are rotatable with respect to said collar, and said second portion including a caterpillar tractor means assembly having means affixed to a deck of said tractor which constitutes part of said selectively controlled power means, and a drive to said tractor means in response to activation thereof by said selectively controlled power means, separate pivotal means attached to said tractor deck at opposite ends thereof, each pivotal means having a segment thereof outwardly disposed beyond the end of said tractor deck related thereto, each said segment having affixed thereto one of said jack structures by attachment to said bearing support collar provided therefor, a substantially curved leaf spring associated with each pivotal means, such that each said jack structure is further attached to said deck by said leaf spring, corresponding jack structures of said first and second units of each said sections being interconnected by a flexible beam having extended ends thereof affixed to said cylindrical housings of said interconnected jack structures, whereby said pivotal means and said leaf spring associated therewith, and said flexible beam maintain said jacks in a generally upright disposition, a foot pad means pivotally connected to the end of said extension of each of said lower extensible means, and means pivotally connected to the end of said extension of said upper extensible means whereon said components are spatially arranged and whereby said shielding means is maintained dependent therefrom so as to extend over all said sections of said apparatus.