Abstract:
An apparatus for testing a rock drill has a base structure, a displaceable structure movable toward and away from the base and a fluid pumping mechanism carried on one of the structures to be driven by the rotation of the rock drill. The air leg of the rock drill is deemed either operational or in need of repair based on whether attempted extension of the leg is sufficient move the displaceable structure away from the base. A control mechanism in a fluid passage fed by the pump output is closable so that a pressure builds up in the passage under operation of the pump. Successful of unsuccessful buildup of the pressure to a sufficient level reflecting good rotational operation of the drill reflects whether the drill component is to be deemed operational or in need of repair. Quick and simple testing of both the leg and drill components is facilitated.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to equipment and methods for testing of rock drills before each deployment for use to determine whether they are in good functional condition or in need of service or repair. 
       BACKGROUND OF THE INVENTION 
       [0002]    Stoper and jack-leg drills are two types of rock drills commonly used in mining operations. These pieces of equipment are deployed to different areas of a mine site as their use is required. As with all equipment, it is desirable to minimize down time in which the rock drill is not available for use. In mining, a particular rock drill will sometimes be deployed from an area at which it is normally stored to a particular location in the mine or use by an operator, only for the operator to discover that the rock drill is not functioning properly. Time is wasted as the defective unit must be transported back out of the mine for repair and a replacement rock drill is deployed in its place. 
         [0003]    Accordingly there is a desire for rock drill testing equipment and methods that facilitate testing of rock drills before their deployment into a mine in order to first establish that the equipment is in good working order, and not in urgent need of service or repair. 
       SUMMARY OF THE INVENTION 
       [0004]    According to a first aspect of the invention there is provided a rock drill testing apparatus comprising: 
         [0005]    a base structure; 
         [0006]    a displaceable structure spaced from the base structure and movable toward and away from the base structure along a linear axis; 
         [0007]    a fluid pumping mechanism mounted to a respective one of the base and displaceable structures, the fluid pumping mechanism thereof being operable by driven rotation of an input shaft thereof extending parallel to the linear axis, the input shaft being rotatable about the linear axis relative to the base and displaceable structures and being engagable by a drill component of a rock drill at an end of the input shaft nearest an opposite one of the base and displacement structures; 
         [0008]    a fluid passage communicating with an outlet of the pumping mechanism; 
         [0009]    a flow control mechanism operably installed on the fluid passage at a distance therealong from the outlet of the fluid pumping mechanism to close and then open the fluid passage with the fluid pumping mechanism running to first cause a buildup of pressure in the fluid passage when closed and then relieve the buildup of pressure in the fluid passage when opened; and 
         [0010]    an indicator mechanism associated with the fluid passage and operable to provide an indication of a status of the buildup of pressure in the flow passage under operation of the fluid pumping mechanism with the fluid passage closed. 
         [0011]    Preferably the fluid pumping mechanism comprises a hydraulic pump and the fluid passage is also communicating with an inlet of the fluid pumping mechanism. 
         [0012]    Preferably the fluid passage comprises a fluid conduit that communicates with the inlet and outlet of the fluid pumping mechanism and a hydraulic fluid reservoir connected inline with the fluid conduit at a position therealong between the flow control mechanism and the inlet of the fluid pumping mechanism. 
         [0013]    Preferably the hydraulic fluid reservoir is mounted on the respective one of the base and displaceable structures on which the hydraulic pump is mounted. 
         [0014]    Preferably the flow control mechanism comprises a pressure relief valve installed on the fluid passage to open the fluid passage only after the pressure buildup therein exceeds a given level. 
         [0015]    Preferably there are provided displacement resisting devices associated with the displaceable structure to resist movement thereof away from the base structure. Preferably the displacement resisting devices are configurable to allow adjustment of resistance to movement of the displaceable structure away from the base structure. 
         [0016]    Preferably the displaceable structure disposed over the base structure and is movable upward and downward away from and toward the base structure. 
         [0017]    Preferably the displacement resisting devices comprises weights carried with the displaceable structure and suspended at a position downward therefrom. Preferably the weights are selectively disconnectable from the displaceable structure to facilitate swapping of different weights for one another on the apparatus. 
         [0018]    Preferably the weights have guide features thereon cooperable with stationary guide members projecting away from the base structure toward the displaceable structure to guide motion of the weights along the guide members during lifting and lowering of the displaceable structure away from and toward the base structure. 
         [0019]    Preferably the guide features comprise collars fixed to the weights and closing around the guide members 
         [0020]    Preferably there are provided stops defined on the guide members for engagement thereagainst by the guide features on the weights under lifting of the displaceable structure away from the base structure by a given distance to prevent movement of the guide features passed upper ends of the guide members. 
         [0021]    Preferably the weights comprise metal plates. 
         [0022]    Preferably the guide members comprise outer tubular members fixed to the base structure and projecting upward therefrom parallel to the linear axis and inner members fixed to and projecting downward from the displaceable structure are slidably received in the guide members to limit movement of the displaceable structure to movement along the linear axis. 
         [0023]    Preferably the indicator mechanism comprises a pressure gauge operably installed on the fluid passage between the outlet of the fluid pumping mechanism and the flow control mechanism. 
         [0024]    Preferably the fluid pumping mechanism is carried on the displaceable structure on a side thereof opposite the base structure and the input shaft projects through the displaceable structure. 
         [0025]    Preferably movement of the displaceable structure is guided by a pair of parallel telescopic supports projecting from the base structure to the movable structure, the telescopic supports comprising stationary sections fixed to the base structure adjacent opposite sides thereof and movable sections slidable relative to the stationary sections toward and away from the base structure, and the displaceable structure comprising a cross member fixed to and extending between the movable sections of the parallel telescopic supports for movement with the movable sections toward and away from the base structure. 
         [0026]    Preferably the stationary sections of the telescopic supports comprise tubular members in which the movable sections of the telescopic supports are slidably disposed. 
         [0027]    Preferably the pumping mechanism is mounted to the displaceable structure. 
         [0028]    According to a second aspect of the invention there is provided a rock drill testing apparatus comprising: 
         [0029]    a base structure; 
         [0030]    a displaceable structure positioned over the base structure at a distance upward therefrom and lowerable and liftable toward and away from the base structure along a linear axis; 
         [0031]    a rotatable element mounted to a respective one of the base and displaceable structures and extending parallel to the linear axis, the rotatable element being rotatable about the linear axis relative to the base and displaceable structures against a source of rotation resistance and being engagable by a drill component of a rock drill at an end of the rotatable element nearest an opposite one of the base and displacement structures; and 
         [0032]    weights carried with the displaceable structure and suspended at positions downward therefrom to resist lifting of the displaceable structure away from the base structure. 
         [0033]    According to a third aspect of the invention there is provided a rock drill testing method comprising: 
         [0034]    positioning a rock drill between a base surface and a displaceable load movable toward and away from the base surface; 
         [0035]    with the rock drill remaining between the base surface and the displaceable load, performing a leg test and a drill test, the leg test comprising attempting to extend a telescopic leg component of the rock drill against the load to move the load away from the base surface and the drill test comprising using a drill component of the rock drill as a drive source for a fluid pumping mechanism to attempt to pump fluid into a closed fluid passage and buildup a pressure level therein; and 
         [0036]    deeming the rock drill either (a) suitable for use if the rock drill passes both the leg test and the drill test by successfully moving the load away from the base surface in the leg test and successfully building up the pressure level in the drill test, or (b) unsuitable for use if the rock drill fails one or both of the leg test and the drill test. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0037]    In the accompanying drawings, which illustrate an exemplary embodiment of the present invention: 
           [0038]      FIG. 1  is a front elevational view of a rock drill test apparatus according to the present invention. 
           [0039]      FIG. 2  is a side elevational view of the rock drill test apparatus. 
           [0040]      FIG. 3  is a front elevational view of a hanger bracket of the rock drill test apparatus. 
           [0041]      FIG. 4  is a side elevational view of a weight of the rock drill test apparatus. 
           [0042]      FIGS. 5A and 5B  are overhead plan and front elevational view of a hydraulic pump mounting bracket of the rock drill test apparatus. 
           [0043]      FIGS. 6A and 6B  are overhead plan and front elevational views of a hydraulic pump mounting spacer of the rock drill test apparatus. 
           [0044]      FIG. 7  is a front elevational view of a hydraulic reservoir mounting bracket of the rock drill test apparatus. 
           [0045]      FIG. 8  is a side elevational view of a pressure relief valve mounting bracket of the rock drill test apparatus. 
           [0046]      FIGS. 9A and 9B  are side elevational and overhead plan views of a weight guiding bracket of the rock drill test apparatus 
       
    
    
     DETAILED DESCRIPTION 
       [0047]      FIGS. 1 and 2  show an apparatus  10  for testing both the pneumatically expanding and contracting leg component and pneumatically rotating drill component of a rock drill, whether a stopper drill or jack-leg drill. The testing apparatus  10  of the illustrated embodiment is configured as an upright stand having a horizontally oriented base frame  12 , a pair of parallel telescopic support leg assemblies  14  projecting vertically upward from the base at opposite sides thereof and a horizontally oriented cross member  16  extending between the support leg assemblies  14  at the movable upper ends thereof opposite the base frame  12 . A hydraulic pump  18  is mounted atop the cross member  16  and has its internal drive shaft coupled with a rod  20  that projects vertically downward through the cross member  16  at a central position between the support leg assemblies  14  to form an extension of the pump drive shaft so that the rod and driveshaft are rotatable together and collectively form an input shaft assembly that is rotatable to drive the pump. For testing of a rock drill, the bottom base end of the rock drill&#39;s air leg is placed atop the base frame  12  of the test apparatus  10 , or the ground therebeneath, and the chuck of the rock drill&#39;s drilling end is locked onto the rod  20 . Expansion of the air leg with the rock drill in this vertically position in the test stand acts to lift the weight of the cross member  16  and the components carried therewith to verify the functionality of the air leg, and driving of the drill component of the rock drill drives the hydraulic pump to build up a pressure in a hydraulic conduit connected to the pump to confirm the rotational functionality of the rock drill. 
       Structure 
       [0048]    The structure of the illustrated testing apparatus  10  is described in further detail as follows. 
         [0049]    The base frame  12  features a pair of feet  22  each disposed immediately beneath a respective one of the telescopic leg assemblies  14  and each formed by a length of rectangular steel tubing extending horizontally in a direction normal to the vertical plane at which the two parallel support legs  14  lie. A central member  24  of the base frame  12  extends horizontally between the two feet  22  at the plane of the support legs  14 , closing off a planar rectangular area bound between the two support legs  14  the cross member  16  and the central frame member  24 . Each support leg assembly  14  features a stationary section  26  defined by another length of rectangular steel tubing fixed at its lower end to the respective foot  22  at a central position therealong to project vertically upward from the horizontal base frame  12 . The upper end of the stationary tube  26  is left open and a respective cross-sectionally smaller piece of steel rectangular tubing fixed at its upper end to the cross member depends downward into the stationary tube  26  through the open upper end thereof to define a movable section  28  of the respective leg assembly  14  slidably disposed within the stationary section to give the leg assembly a telescopic configuration. Triangular vertically oriented gusset plates  55  are fixed between the central frame member  24  and the stationary sections  26  to better support the leg assemblies  14 . 
         [0050]    The telescopically assembled linear sections  26 ,  28  of the leg assemblies  14  allow the cross member  16  to move relative to the base frame  12 , but substantially limit this motion of the cross member  16  to vertical displacement along a linear vertical axis A normal to the horizontal plane of the base frame  12 . The displaceable cross bar  16  of the illustrated embodiment is defined by a piece of rectangular steel tubing of the same dimension as that of the movable inner sections  28  of the leg assemblies  14 , this cross bar being fixed to and crossing the upper ends of the inner leg sections  28  so as to extend laterally outward past the two leg assemblies on opposite sides of the base frame  12 . At these shoulder-like end portions  16 a of the cross member  16  projecting outward past the respective leg assemblies  14 , hanger brackets  30  are fixed to and project a short distance downward from the bottom surface of the cross member  16 . In the illustrated embodiment, each of the two hanger brackets is defined by a small metal plate  30   a  fixed to the cross member  16  at an upper end, for example by welding, and having a single round hole  30   b  passing normally therethrough near a bottom end of plate furthest from the cross member  16 , as shown in  FIG. 3 . A shackle  32  passes through the hole of each hanger bracket  30  and a vertically hanging steel cable  34  passes through the opening of the shackle  32  and then folds back over itself to define an upper end of the cable connected to the shackle and hanger bracket, the cable being secured to itself by cable clamps  36  to define this looped upper end. A likewise looped bottom end of the cable formed by another portion of the cable where it is folded back over itself and secured by additional cable clamps  38  carries a weight  40 . As shown in  FIG. 4 , the weight of the illustrated embodiment is provided by a generally rectangular steel plate  40   a  having an integral lug  40   b  projecting vertically upward from a top horizontal edge of the otherwise rectangular weight. A round hole  40   c  passing normally through the flat lug  40   b  has another shackle  44  passed through it, which in turn has the looped bottom end of the cable  34  passed through it to form the connection between the cable and the weight  40 . 
         [0051]    Each weight  40  is provided with a guide bracket  42  projecting from the inwardly directed face of the weight facing toward the weight on the opposite side of the stand. The guide bracket  42  cooperates with the plate structure of the weight to define a rectangular collar that closes about the stationary lower section  26  of the respective leg assembly adjacent the weight  40 . With reference to  FIG. 9 , the guide bracket  42  of the illustrated embodiment is a flat bar having been bent at right angles at four points along its width to take on a winged U-shape with straight flat sections and right angle corners. The resulting guide bracket  42  has two spaced-apart coplanar foot sections  42   a  at opposite ends, two parallel leg sections  42   b  projecting at right angles from the adjacent inner ends of the foot sections  42   a  and a central section  42   c  parallel to the foot sections to perpendicularly interconnect the leg sections  42   b  at ends thereof opposite the foot sections. The central and leg sections  42   b,    42   c  define a squared-off U-shape, and the foot sections define wings of this U. Each foot section  42   a  has a round through hole  42   d  passing normally therethrough to receive a respective one of two threaded studs  40   d  projecting normally from the inwardly directed face of the respective weight  40  at symmetrical positions horizontally across a central vertical axis  40   e  of the weight&#39;s plate structure. The U-shape of the guide bracket  42  has its feet  42   a  placed against the inner face of the weight from the side of the respective leg assembly  14  opposite the weight to slide the holes  42   d  of the guide bracket  42  over the studs  40   d  of the weight for tightening of nuts  44  onto the studs from the side of the feet  42   a  opposite the face of the weight to fasten the guide bracket onto the weight. As a result, the stationary lower section  26  of the telescopic support leg assembly  14  is disposed within a rectangular area bound by the three sides of U-shaped portion of the guide bracket  42  and the inner face of the weight. 
         [0052]    Referring to  FIG. 1 , lifting of the cross member  16  away from the base frame  12  acts to also lift the inner sections  28  of the telescopic support legs  14  and the weights suspended from the cross member by the hanger brackets  30  and cables  34 . The guide brackets  42  on the weights  40  slide along the stationary lower sections  26  of the support leg assemblies  14  to guide the weights during this lifting and subsequent lowering so that the weights follow linear paths parallel to those of the displacement of the cross member  16  and inner movable sections  28  of the support legs  14 . The stationary lower sections  26  of the telescopic leg assemblies  14  thus not only define guides to establish the linear motion path of the cross member and attached inner leg sections  28 , but also define guides to establish parallel paths of motion for the weights. A small rectangular plate  46  fixed to the stationary lower section  26  of each telescopic leg assembly  14  projects horizontally inward therefrom a short distance toward the opposite leg assembly to form a stop that limits upward sliding of the guide brackets  42  on the weights to prevent sliding of the guide brackets  42 , and the bottom ends of the movable inner sections  28  disposed at an elevation below the guide brackets  42 , from sliding upwardly past the stops and off the top ends of the stationary lower sections  26  of the leg assemblies  14 . 
         [0053]    At a central position along the cross member  16 , a vertical hole passes therethrough along the central axis A between the support leg assemblies  14 . Two flanged roller bearings  48   a,    48   b  are mounted on the cross member, one on the upward facing side thereof to define an upper roller bearing  48   a  and one of the downward facing side of the cross member to define a lower roller bearing  48   b.  The central opening through each of these two roller bearings  48 ,  48   b  is concentrically aligned with the vertical hole through the cross member  16 . In the illustrated embodiment, the two roller bearings are the same and have their flanges bolted to the cross member  16  by bolts passing through the flanges of both bearings and the cross member therebetween. A thrust bearing  50  is mounted to the lower roller bearing  48   b  at a position immediately therebeaneath. The rod  20  is made of drill steel and passes vertically upward form its bottom end through the thrust bearing  50 , lower roller bearing  48   b,  cross member  16  and upper roller bearing  48   a.  At its top end, the rod  20  is fixed to a mechanical coupling  52  that couples the rod  20  to the drive shaft of the hydraulic pump  18 . 
         [0054]    A pump mounting bracket  54  installed on the cross member  16  supports the hydraulic pump  18  at a distance above the cross member  16 . The pump mounting bracket of the illustrated embodiment, shown in isolation in  FIG. 5 , is formed by a flat steel bar bent into a shape somewhat similar to that of the guide brackets  42 , but on a larger scale. The installed pump mounting bracket  54  features two coplanar horizontal feet  54   a  disposed on opposite sides of the rotational rod and bearing assembly at the center of the cross member  16 , a pair of legs  54   b  projecting convergingly upward from adjacent inner ends of the feet  54   a  nearest the rod  20  and a central section  54   c  horizontally interconnecting the top ends of the converging legs  54   b  at a position over the connection of the mechanical coupling  52  to the rod  20 . A pair of round steel cylindrical spacers  56 , one of which is shown in isolation in FIG.  6 , each feature a bore  56   a  passing vertically therethrough along the longitudinal axis of the spacer&#39;s cylindrical shape. Each spacer is disposed between the top surface of the cross member  16  and the bottom surface of a respective foot  54   a  of the pump mounting bracket  54 . A bolt passes vertically through the cross member  16 , the bore  56   a  of the spacer  56  and a through hole  54   d  in the respective foot  54   a  of the pump mounting bracket and is fitted with a mating nut to clamp these elements together and secure the pump mounting bracket  54  in place atop the cross member  16 . The drive shaft of the pump  18 , or part of the mechanical coupling  52  fixed thereto, passes vertically through a central through hole  54   e  in the central section  54   c  in the pump mounting bracket. Four mounting holes  54   f  near the four corners of the central section  54   c  of the pump mounting bracket  54  are provided to receive fasteners to facilitate mounting of the housing of the pump  18  to the top surface of the pump mounting bracket&#39;s central section  54   c.    
         [0055]    A reservoir  58  containing hydraulic fluid is also mounted atop the cross member  16  using a bracket. The reservoir mounting bracket  60  of the illustrated embodiment, shown in isolation in  FIG. 7 , is a flat steel bar bent into three linearly extending sections disposed at right angles to one another to create two legs  60   a  fixed to the cross member, for example by welding, to project vertically upward from the top surface of thereof and a central section  60   b  extending horizontally between the upper ends of these legs. The hydraulic fluid reservoir  58  is fixed atop the central section  60   b  of the reservoir mounting bracket  60  and includes an oil filler tube  58   a  projecting vertically upward from within the reservoir. A first section of flexible tubing  62  is connected to the reservoir at one end in sealed fluid communication with the reservoir&#39;s interior through a port in a wall of the reservoir and is coupled to the pump  18  at the opposite end in sealed fluid communication with an inlet  18   a  of the hydraulic pump  18 . A second section of flexible tubing  64  is connected in sealed fluid communication with an outlet  18   b  of the hydraulic pump at one end and with in an inlet side of a pressure gauge  66  at an opposite end. A third section of tubing  67  is connected in sealed fluid communication with an outlet of the pressure gauge  66  at one end and with in an inlet side of a pressure relief valve  68  at an opposite end. A final fourth section of tubing  70  is connected in sealed fluid communication with an outlet of the pressure relief valve  68  at one end and with an inlet port of the reservoir  58  at the opposite end. The tubing sections thus define a fluid flow passage that connects the inlet and outlet of the pump and by way of a conduit having an inline installation thereon of a pressure gauge, pressure relief valve and fluid reservoir, in this order, from the pump outlet to the pump inlet. In the illustrated embodiment, the reservoir and pressure relief valve are carried adjacent opposite ends of the cross member  16  on opposite sides of the centrally mounted pump, and the pressure relief valve  68  is mounted on top of the cross member using a valve supporting bracket  69 , shown in isolation in  FIG. 8 , formed by a vertically projecting plate having fastener holes  69   a  and being fixed to the top surface of the cross member  16 , for example by welding. 
         [0056]    Although not readily visible in the drawings, the test stand apparatus may have rubber pads of ¼-inch thickness placed between each foot of the pump mounting bracket and the respective spacer, between each spacer and the cross member and between the pump housing and the central section of the pump mounting bracket to provide vibratory isolation between the pump and the cross member during operation of the pump. 
       Operation 
       [0057]    The use of the illustrated testing apparatus  10  is described in further detail as follows. 
         [0058]    The air leg of a stoper or jack-leg type rock drill is stood vertically between the parallel support leg assemblies  14  of to engage the base end of the air leg with the central frame member  24  or the ground on which the base frame  12  is disposed. For example, a stoper drill with a pointed tip of its air leg&#39;s piston rod may engage the central frame member  24  by inserting the pointed tip into a vertical hole passing through the central frame member&#39;s  24 , or at least through the horizontal top wall of the tubular structure of the illustrated central frame member  24 , at the central vertical axis A of the test stand apparatus, as generally indicated at  72  in  FIG. 1 . The claw-like foot of a jack-leg drill may instead be placed over the central frame member  24  to instead seat upon the ground on opposite sides thereof. The frame assembly or the ground on which it is disposed to support the test stand apparatus thus forms a stationary horizontal base structure against which air leg may push when telescopically expanded under pneumatic actuation. 
         [0059]    The stand is built sufficiently tall so that the cross member  16  is high enough to accommodate the length of the rock drills to be tested between the base structure and the bottom end of the rod  20  when the cross member is in its lowest position, which may correspond to the movable sections  28  of the support legs  14  sitting atop the feet  22  of the base frame  12 , the cross member  16  sitting atop the top ends of the stationary sections  26  of the support legs  14 , or engagement of some other stop-defining configuration denoting the fully retracted position in which the cross member is nearest the base structure. The drill chuck of the rock drill is opened, the air-leg is telescoped to expand a short distance to position the rod  20  within the drill chuck, and the chuck is subsequently closed around the rod  20  of the test stand for gripping thereof in the same manner as it would engage a rock drill bit when prepared for use of the drill at a mining site. With the air leg and drill component of the rock drill coupled to a suitable source of compressed air in its normal manner, the rock drill is now considered installed in the test stand apparatus and ready for testing. 
         [0060]    The stand enables testing of both the air leg and the drill component of the rock drill simultaneously, or separately but without requiring any removal of the rock drill or reconfiguration of any aspect of the rock drill&#39;s installation within the test stand. 
         [0061]    In a leg test or lift test, the air leg control is used to introduce compressed air to force the expansion of the air leg and accordingly displace the drill component at the top of the air leg upward, this acts to lift the cross member  16  and all components of the apparatus mounted thereon and carried therewith. The mass of the weights  40  supported from the cross member  16  are selected so that the overall mass of the cross member and components carried therewith is low enough so that the drills being tested should be able lift this mass through operation of the air leg pneumatic controls in the expansion driving manner when the drill is in good operating condition, but sufficiently high so that a rock drill air leg not in such good operation condition, but rather being in need of service or repair would not lift the cross member and components carried therewith. Using a shackle at one or both of the connections between each cable and the cross member and respective weight allows easy removal and installation of weights on the apparatus to allow changing of the lift-resisting weight to enable testing of rock drills with different air leg specifications and capabilities. 
         [0062]    In a drill test or torque test, the drill component is driven to drive rotation of the rod  20 , which in turn drives operation of the hydraulic pump  18  via the driveshaft thereof. This draws hydraulic fluid from the reservoir through the pump, forcing it onward past the pressure gauge into the normally closed pressure relief valve. With this valve mechanism closed, the pumping of fluid from the pump against this closure of the conduit builds up the pressure within the portion of the conduit between the pump and the relief valve. Once this pressure buildup exceeds the threshold pressure value of the relief valve, the valve opens to allow the pressurized fluid to continue onward through the remainder of the conduit back to the reservoir  58 . An operator of the test apparatus can confirm that the drill&#39;s torque is driving the pump sufficiently to reach this threshold pressure value in the closed section of the conduit by monitoring the pressure gauge. As shown in  FIG. 2 , the pressure gauge can be obliquely angled downward for easy viewing by the user from below. If no pressure buildup and subsequent relief is occurring, then the drill is not sufficiently driving the pump. Like with the mass selected to resist the lifting action on the test stand by the air leg, the threshold or actuating value of the relief valve is selected on the basis that driving of the pump with a properly operating drill will be capable of exceeding the this pressure value in the conduit, but a drill in need of repair would not reach the threshold pressure value. Use of an adjustable pressure relief valve allows this value to be changed to accommodate testing of rock drills with different drill specifications and rotational capabilities. 
         [0063]    The testing apparatus can be calibrated once by determining the load lifting and rotational capabilities of a particular type of drill, or of different drills having similar capabilities or ratings, and then used repeatedly to test multiple drills of the same type or ability. The individual tests require no taking of measurements and no comparison of performance values against the known performance characteristics of a properly functioning drill of the same type. The operator of the test stand merely needs to visually confirm the lifting of the cross member and visually confirm the fluctuating pressure in the fluid passage under the opening and subsequent re-closing of the relief valve. Failure of the rock drill to upwardly displace the cross member in the leg test indicates repair of the air leg component of the rock drill is likely required, and accordingly the rock drill should not be dispensed for use in a mine. In the same manner, failure of the rock drill to build up sufficient pressure to actuate the relief valve indicates repair of the drill component of the rock drill is likely required, and accordingly the rock drill should not be dispensed for use in a mine. Acknowledging failure of one or both of the tests prevents an unsuitable rock drill from being sent out for use on the job, and identifying which of the two tests failed provides further information on which of the two components requires repair. Not only is time not wasted on transporting the rock drill into a mine, only to realize it is not functional and have to transport it back out of the mine for repair, but also diagnostic and/or disassembly and reassembly time during repair is minimized since which one(s) of the component require repair has already been identified. 
         [0064]    The present invention can therefore be employed at a mining site, for example at a shop or storage area outside the mine, to quickly and easily test each rock drill before its deployment into the mine to improve productivity by reducing otherwise wasted transport and repair downtime of a rock drill. 
       Variations 
       [0065]    The particular materials and part configurations described with reference to the illustrated embodiment reflect a prototype construction employed in development of the present invention, and will be appreciated that material types, structure of individual parts and configuration of the parts with one another may be varied without departing from the scope of the present invention. For example, while mild steel plates and bars and steel tubing were used in the prototype, other materials may be employed, for example to reduce the weight of the apparatus to increase portability, provided that the resulting parts are of suitable strength for the end use of the apparatus. Telescopic rail assemblies, as opposed to nesting of a tube or bar within a larger outer tube, may be employed for sliding lifting and lowering of the cross member. It also may be possible to replace the telescopically supported cross member with a displacable structure that slides or rolls along vertical rails projecting away from the base and has its fully retracted position nearest the base defined by stops in the rails at a distance above the base. 
         [0066]    In a further alternate embodiment, the testing apparatus may be laid out horizontally instead of being configured as the vertically extending test stand of the illustrated embodiment. A fixed body structure defining a vertical base surface against which the air leg can push could have a horizontally displaceable structure spaced therefrom, the rock drill being being placeable between the structures to bear against the fixed structure and displace the movable structure away therefrom under expansion of the leg. Telescopic or rail supports could again guide or limit the motion of the displaceable structure to occur in a linear manner. However, the vertical stand construction has the benefit that the weight of the displaceable structure and components carried therewith acts to automatically return it to the retracted position, and also benefits from a smaller footprint (i.e. less occupied surface area/floor space). It will also be appreciated that the pump used to test the torque or rotational performance of the rock drill, and the associated components cooperating the pump, may alternatively be mounted on the stationary base, as opposed to the displaceable structure movable relative thereto. 
         [0067]    The suspended weights of the illustrated embodiment improve safety by keeping a significant portion of the lift-resisting weight lower than if carried directly on the cross member, making the apparatus less top-heavy, and the weight guides prevent the weights from swinging or swaying and potentially injuring the operator or other personnel. However, other test systems or methods in which weights are not suspended below the cross member, including horizontally oriented test apparatuses mentioned above, could still make use of the easy to evaluate torque test using the pumping and pressurization of a fluid as the performance marker. Similarly, vertically oriented stands using the suspended weights may benefit from their advantages without necessarily using a fluid-based torque test if some other source of rotational resistance is instead employed to allow visual confirmation of a rock drill&#39;s rotational performance when the rotational resistance is overcome. In the illustrated embodiment, the lifting resistance is adjustable by adding to or reducing the weight carried by the cross member and attached movable sections of the support legs and the rotational resistance is adjustable by changing the threshold pressure value of the relief valve benefits from flexibility and adaptability, but test systems intended for use with only one particular rock drill type may be constructed to have fixed resistances based on the known performance characteristics of a properly functioning drill of that type. 
         [0068]    While the illustrated embodiment uses a pressure gauge to reflect whether the rotational drive of the drill is in good operating condition based on the pressure in the fluid passage, it may be possible to use other indicators. For example, it may be possible to configure the relief valve to perform some function upon reaching the threshold pressure that provides an indication of a successful torque test to the operator. While this could trigger an audible signal, preferably a visual signal or indicator is used due to high noise levels associated with the operation of a rock drill. 
         [0069]    It will also be appreciated that the fluid being pressurized through the rotation of the rock drill need not necessarily be a hydraulic fluid or even a liquid, as an alternative embodiment could alternatively pressurize and subsequently release a gas or combination of gases. For example, one embodiment could use coupling of the rock drill chuck to the driveshaft of an air compressor discharging into a closed conduit or vessel until the pressure buildup exceeds the actuating value of a pressure relief valve installed thereon. The air compressor could draw on ambient air from the environment in which the apparatus is installed and bleed the pressurized air off back into the environment through a suitable discharge after the pressure relief valve is opened. 
         [0070]    Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.