Abstract:
A protective shield for machines having an operator station protects an operator located on the operator station during operation of the machine. The protective shield defines a flexible curtain of elongated members which covers an exposed side of the operator station, but yet is also of a construction that allows the operator to reach and see through the curtain when desired. The protective shield has an adjustable height to accommodate a variety of machines and to adjust to underground mines having different sizes and shapes. The protective shield is easily removable from and reattachable to machines without the use of additional tools, thereby enhancing its versatility and usefulness. In a preferred embodiment, the protective shield comprises a somewhat stretchable chain mesh, which hangs from a roof canopy extending along side the operator station.

Description:
FIELD OF THE INVENTION 
     The present invention relates to machines used in connection with underground mining, and more particularly, to machines having an operator station for supporting an operator. Specifically, the present invention relates to a protective device to protect the operator during operation of a machine. 
     BACKGROUND OF THE INVENTION 
     There are many known machines used in connection with underground mining for coring, drilling, mining, or the like. One particular type of machine used in connection with underground mining is commonly referred to as a bolting apparatus. An example of one such bolting apparatus is described in PCT International Application No. PCT/AU99/00014 (WO 99/36671), which is incorporated herein by reference. As can be appreciated by those skilled in the art, underground mining involves the need to prevent the collapsing of overhead ceilings or roofs and side walls or ribs of underground mines in order to prevent injury to personnel and damage to mining equipment. Roof bolting and rib bolting are those processes that secure the roofs and sidewalls of underground mines to other stable strata. Generally, bolting apparatuses include an operator station for supporting one or more operators during operation of the machine. The operator station typically serves to define a support platform upon which the operating personnel can stand and walk as needed Some machines include adjustable platforms or deck extensions so as to increase the size of the operator working station. 
     It is also known to provide machines used in connection with underground mining with a roof canopy in order to cover the operator station so as to protect the operator from debris or the like which may fall from an entry roof of an underground mine. It is also known to provide machines with vertically extending rigid steel rib components adjacent to the operator station so as to protect the operator from material which may fall from the walls of the mine. 
     Bolting apparatuses generally follow continuous mining equipment that advances into an underground seam and, as material is won therefrom, an entry or opening is formed in the underground seam. The size of the entry is dependent at least in part on the type and size of the continuous mining equipment used to cut the entry. Although the known vertically extending rigid steel rib components are capable of protecting an operator during operation of the machine, their usefulness is limited because they are not adjustable to accommodate the various different types of machines having various sizes, nor are they adjustable to accommodate changes in the size and shape of the entry of an underground mine. As known, the overall height of an operator station may vary depending on the size and shape of the entry formed in an underground mine. The known vertically extending rigid steel rib components are not particularly suitable for use with machines used in connection with underground mining of varying types and sizes, nor are they particularly suitable for use in those situations where the size and shape of the entry of an underground mine changes, because the nonadjustable rigid rib components may limit the location of a roof canopy with respect to an operator platform, may limit the height range on the folding deck extensions if such extensions are utilized, and may not provide full height protection for an operator. Another problem with the known rigid rib components is that the inflexibility of the rigid ribs makes it somewhat difficult for personnel to reach through the rigid ribs, thereby adversely affecting the overall efficiency of the underground mining operation. It was also not possible to temporarily remove the rigid ribs should the operator need to access the side of the machine. 
     SUMMARY OF THE INVENTION 
     The invention provides a protective shield that substantially covers an exposed side of the operator station to protect the operator during operation of the machine. The protective shield solves the above noted problems and other problems of the prior art. More particularly, the invention provides an adjustable protective shield, which is usable with different types of machines having various sizes. The shield is adjustable to accommodate various changes in the size and shape of the entry of an underground mine to better protect the operator during operation of the machine. The shield is also flexible and is easy to handle and is removable from and reattachable to the same machine or a variety of different machines, if desired 
     One of the principal features of the protective shield is that it is adjustable to cover the exposed side of the operator station with no particular regard to the height of the exposed side of the operator station as such may change from time to time. Another feature of the protective shield is that it is flexible to allow the operator to easily reach around and see through the shield, as needed. Another feature of the protective shield is that it is easily and efficiently removable from and reattachable to the same or multiple machines all without the use of additional tools. Another feature of the protective shield is that it has a somewhat elastic nature. 
     Preferably, the protective shield includes a set of elongated members. The set of elongated members defines a flexible curtain, which advantageously enables the operator to reach and see through, but which also, at the same time, protects the operator from harm from flying debris or the like. In a preferred embodiment, the elongated members are chains such that the protective shield comprises a chain mesh extending between the canopy and the operator-working platform. Preferably, the roof canopy is designed to support the protective shield such that the protective shield is suspended from the canopy, thereby substantially covering an exposed side of the operator station. In a preferred embodiment, each chain includes an extension spring for additional flexibility as needed. 
     Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of a machine used in connection with underground mining embodying the present invention. 
     FIG. 2 is a front elevational view of the machine of FIG.  1 . 
     FIG. 3 a  is an enlarged portion of FIG. 2 illustrating a protective shield according to the present invention. 
     FIG. 3 b  is a side elevational view of the protective shield as shown in FIG. 3 a.    
     FIG. 4 is an enlarged portion of FIG. 3 b  showing in greater detail a top curtain bracket of the machine. The curtain bracket is designed to receive and to support one end of the protective shield. 
    
    
     Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. The use of “consisting of” and variations thereof herein is meant to encompass only the items listed thereafter and the equivalents thereof. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Illustrated in FIGS. 1 and 2 is a machine  10  embodying the invention. The depicted machine is used in connection with underground mining and is referred to as a bolting apparatus. It should be understood that the present invention is capable of use in other machines known in the art and the bolting apparatus is merely shown and described as an example of one such machine. 
     The machine  10  includes a frame  14  having a front end  18 , a back end  22  and lateral sides  26  and  30 . The frame  14  is supported for movement over the ground or floor  34  of an entry or opening  38  by track units  40 , which may be crawler tracks. In other embodiments, other means of moving the frame  14  may be used. At least one bolter  42  is operatively mounted to the front end  18  of the frame  14 . At least one roof support  46  including an upwardly extending roof engaging member and a downwardly extending floor engaging member is operatively attached to the front end  18  of the frame  14  apart from the bolter  42 . An operator station  50  having at least one exposed side on the frame  14  supports an operator during operation of the machine  10 . Deck extensions  54  increase the size of the platform  50  upon which the operator can stand and walk. In other embodiments, deck extensions may not be used. A canopy  58  supported by the frame  14  extends over the operator station  50 . The canopy  58  includes a canopy extension  62  to allow the canopy  58  to extend over the deck extensions  54  when the deck extensions  54  are utilized. 
     Bolting apparatuses, such as the bolting apparatus  10  shown in FIGS. 1 and 2, generally operate as follows. Typically, after a mining machine, such as a continuous miner, has formed an appropriate entry extension or opening into an underground seam, the mining process is interrupted and the mining machine and any supporting conveying apparatus for the won material is moved to allow the bolting apparatus to be driven into the entry. Generally, one or two operators control the bolting apparatus. The mobile bolting apparatus is driven to a point where it is located directly beneath a portion of an entry roof that is to be bolted. Thereafter, the roof supports are extended to engage the roof of the entry and the floor of the entry to provide load-bearing columns between the roof and the floor. After the roof supports are extended in this manner, the bolting process can begin. A roof canopy is usually provided to protect the operator from material that may fall from the entry roof. The operator is free to move about the operator station so as to control the operation of the bolting apparatus. At least one bolter is activated to install bolts in the entry roof in a conventional manner. After the bolts have been installed and the bolter is returned to its inactivated position, the roof supports are retracted to permit the mobile bolting apparatus to be driven forward to the next position where additional bolts are to be installed. 
     The construction and operation of the bolting apparatus  10  has not been shown and described in great detail because the construction and operation thereof is not significant in terms of the present invention. For a more complete description of a bolting apparatus, see the previously mentioned PCT Application that has been incorporated herein by reference. 
     As already noted, during operation of a machine underground, material may fall off the walls of the mine, thereby possibly creating a hazardous condition for the operator. To provide operator protection, the machine  10  includes a protective shield  66 . The protective shield  66  substantially covers at least one exposed side of the operator station  50  (the left side in FIG. 2) to protect the operator during operation of the machine  10 . 
     Referring now in particular to FIGS. 3 a  and  3   b  in conjunction with FIGS. 1 and 2, the protective shield  66  is in the form of a curtain including a set of elongated members  74 . The operator is able to see and reach through the curtain  66 , if needed. And as more fully explained below, some or all of the curtain  66  can be easily removed when needed to permit the operator to access the side of the machine  10 , if necessary. 
     The elongated members may be of many different kinds and types of material suitable for use according to the principles of the present invention. In the preferred embodiment, the elongated members  74  are chains including alternating, perpendicular, interconnected linked members in the form of chain links  94 . The chains may be of many different types of chain, but galvanized, grade 30, ½-inch proof coil chain is preferred. For reasons that will be more apparent below, each chain  74  is connected to an adjacent chain  74  with a chain connector  103  thereby partially increasing the stability of the protective shield  66  by forming a chain mesh. Although various chain connectors may be used, wide jaw, zinc plated, ½ inch threaded chain connectors are preferred. 
     The protective shield  66  extends between a top curtain bracket  86 , which is mounted on the canopy extension  62 , and a bottom curtain bracket  90 , which is mounted on the deck extension  54 . If the canopy extension  62  or deck extension  54  is omitted, the brackets  86  and  90  can be connected directly to the canopy or deck. The brackets can be made of any number of different materials, but steel is preferred. 
     The lowermost link  94  of each chain  74  is attached to the bottom curtain bracket  90  by a respective chain connector  105 , which passes through a respective hole  112  in the bottom bracket  90 . Although various connectors may be used, standard jaw, zinc plated, {fraction (9/16)} inch threaded chain connectors are preferred. 
     With additional reference to FIG. 4, the upper end of each chain  74  is connected to the upper curtain bracket  86  by passing the chain  74  through a respective slotted opening  106  in the bracket  86 . Each opening  106  includes a pair of perpendicular slots  110  (one horizontal and one vertical) sized to allow the chain links  94  of the associated chain  74  to pass through the opening  106 . After the chain  74  is pulled through the opening  106  so that the chain  74  is generally taut, although flexible enough to allow the operator to move the chain  74  as desired, the chain  74  is released so that one of the last two links  94  pulled through the opening  106  catches on the bracket  86 , in the lower portion of the vertical slot  110 , due to the force of gravity. This substantially prevents the chain  74  from moving further out of the opening  106 , and thus keeps the chain  74  suspended from the bracket  86 , unless the chain  74  is manually removed from the opening  106 . When desired, more or less of the length of the chains  74  may be pulled through the slots  110  of the upper curtain bracket  86 , thus shortening or lengthening the curtain  66 . Further, some or all of each of the tops of the chains  74  may be removed from the slots  110 , if desired, to permit the operator to have access to the side of the machine  10 . 
     The ability of the length of the chains  74  to be shortened or lengthened with respect to the frame  14  provides the protective shield  66  with an adjustable height. The chains  74  are flexible in relation to one another so as to allow the operator to easily reach and see through the protective shield  66  whenever such action is desired. The chains  74  can be manually handled without the use of additional tools to adjust the protective shield  66  as desired. 
     Referring again to FIGS. 3 a  and  3   b , each chain  74  preferably includes a spring mechanism  120  interposed or extending between a pair of chain links  94  between the brackets  86  and  90 . Although various spring mechanisms may be used according to the principles of the present invention, a heavy-duty, stainless steel safety draw bar extension spring is particularly suitable for use. Such devices, which are well known in the art, include two overlapping brackets or members  124  capturing a spring  128  such that the spring  128  is compressed when the mechanism extends. The spring mechanisms  120  enable the chain curtain  66  to better absorb the impact caused by debris hitting the shield  66 . Moreover, the spring-like nature of the shield  66  provided by the spring mechanisms  120  helps prevent damage to the chains  74  or chain links  94  if the operator inadvertently over-extends the height of the canopy  58 . 
     As an additional safety feature, the first link  94  of the end portion of each chain  74  (the portion that has been passed through the slot  106 ) is preferably connected to one of the links  94  of the main portion of the chain  74  (the portion extending between the brackets  86  and  90 ) with a connector, such as a chain connector  103 . This substantially prevents the chain  74  from being inadvertently pulled out of the slot  106  and also substantially prevents the end portion of the chain  74  from freely swinging in an uncontrolled manner during operation of the machine  10 . It is important that the end portion of the chain  74  be connected to the main portion of the chain with enough slack in the end portion so that the spring mechanism  120  is allowed to extend to its full extent. 
     Variations and modifications of the foregoing are within the scope of the present invention. It is understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. For example, it is envisioned that the protective shield could suspend from the frame or canopy without the need for securing the bottom end of the protective shield to the frame or other bracket. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention. The claims are to be construed to include alternative embodiments to the extent permitted by the prior art. 
     Various features of the invention are set forth in the following claims.