US 3508619 A
Description (OCR text may contain errors)
April 28, 1970 M. C. HUFFMAN HOSE GUIDE FOR ROCK DRILLS Filed Aug. 13, 1968 c J o I 4| O4 a 2 Sheets-Sheet 1 //vl /vTOR Merv/n C Huffman AGE/VT April 28, 1970 M. c, HUFFMAN 3,508,619
HOSE GUIDE FOR ROCK DRILLS Filed Aug. 13, 1968 2 Sheets-Shzgt 2 United States Patent US. Cl. 173-147 14 Claims ABSTRACT OF THE DISCLOSURE A guide and positioning mechanism for the motive fluid hoses of a mast mounted rock drill comprising a hose reel and frame assembly slidably mounted on the drill mast and driven along the mast at a predetermined speed relative to the drill by a transmission unit. The transmission unit includes two shaft and sprocket assemblies rotatably mounted on the frame with each of the shafts having a sprocket engaged with one of the oppositely moving strands of an endless drill feed chain. The respective transmission shafts also mount two speed reduction sprockets of different diameters which are connected by a second endless chain. A predeterminable diameter ratio between the speed reduction sprockets provides for driving the reel and frame along the mast at any selected speed relative to the drill.
BACKGROUND OF THE INVENTION Conventional percussion rock drills require a plurality of flexible fluid conductors leading from a source of pressure fluid via a bank of control valves to the drill proper for conducting the motive fluid to the drill percussion motor and for providing hole cleansing fluid. Some types of drills also require additional fluid conductors for drill steel rotation motors. For drills Which are mounted on masts or guide shells it is desirable to provide for positioning or guiding the elongated fluid conductors or hoses under moderate tension to prevent them from becoming entangled, kinked, or otherwise damaged as the drill is fed back and forth along the mast during normal operation.
An example of a flexible fluid conductor guide and positioning mechanism in the prior art is disclosed in US. Patent 3,162,253 to J. C. Curtis. The Curtis patent discloses a hose reel mounted on the drill mast of a conventional rock drilling mechanism of the type which comprises an endless chain for feeding the drill along the mast. In the arrangement of Curtis the flexible hoses are looped over a reel or sheave which in order to provide for proper tension on the hoses is required to be advanced along the mast at one half the speed of the drill. In order to obtain the desired speed ratio between the drill and hose reel, the Curtis device requires separate endless drive chains extending substantially the entire length of the mast and journaled on separate sprocket assemblies of diameters selected to provide for the proper relative linear velocity of the hose reel and drill. Other devices known in the prior art include cable and drum assemblies which require separate drive means for advancing and retracting the hose reel. Generally, known mechanisms, inclusive of the types mentioned above, are unduly complicated mechanically and therefore require additional maintenance of the drilling equipment as well as adding substantial weight and bulk to the drill support structure.
SUMMARY OF THE INVENTION The present invention resides in an improved hose positioning and tensioning mechanism comprising a grooved reel slidably mounted on a guide shell or mast of a P CC drilling apparatus, the reel being drivably connected to a transmission means engaged by and movable with an endless drill feed chain. The invention further provides for a reel transporting means which is advantageously connected solely to a conventional drill feed chain. The positioning reel drive transmission provides for feeding the reel in the direction of the strand of the drill feed chain to which the drill is attached but at a velocity less than the drill itself.
A particularly advantageous aspect of the invention resides in the provision of a transmission having a speed reduction means comprising a flexible endless drive element engaged with a pair of speed reduction wheels of differential diameter whereby a predetermined velocity of the transmission relative to a flexible endless feed means is achieved.
A specific object of the present invention is the provision of a drive transmission for a conductor positioning reel which is operable directly from an endless drill feed chain to drive the reel at a velocity equal to one half the feed rate of the drill to which the conductors are attached.
Another advantageous aspect of the present invention is the compact and simplified construction of the reel drive transmission which is desirably housed within the normal cross section envelope of a drill mast. The transmission thereby is protected from possible damage from falling rock and debris, and furthermore does not add additional bulk to the mast and associated structure. Reliability and maintainability of the drill structure is enhanced by the compact and easily accessible mechanism. Further advantages and objectives realized with the present invention will be better understood upon reading the detailed description below.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal side view, partially sectioned, of a drill mast and feed chain assembly.
FIG. 1a is a continuation of FIG. 1 from the line aa illustrating the remainder of the drill mast and feed chain assembly including the drill and the hose positioning and tensioning mechanism.
FIG. 2 is a section view taken along the line 2-2 of FIG. 1a.
FIG. 3 is a section view taken along the line 33 of FIG. 1a.
FIG. 4 is a schematic representation of the feed chain and the transmission of the hose positioning and tensioning mechanism including representative velocity vectors of the respective components in the forward feed condition.
FIG. 5 is a front elevation of a crawler mounted rock drilling machine illustrating the flexible motive fluid hoses trained over the positioning and tensioning reel.
DESCRIPTIONOF THE PREFERRED EMBODIMENTS 10. The mast assembly 10 comprises inwardly facing elongated channel members 12 and 14 joined by intermediate members such as at 16 and 18 (FIGS. 2 and 3) to form a rigid support for slidably mounting a fluid operated percussion drill motor 20 ona slide 22. The lower end of the mast assembly 10 includes a bracket 24 for mounting a stabilizing plate 26 and for supporting a drill steel centralizer 28 for guiding the extension drill steel 30. The
mast assembly 10 also includes a mounting cone 32 which cooperatively mounts on a positioner and boom assembly, not shown, of any of a number oftypes well known in the art of adjustable drill mountings.
The lower end of the mast assembly shown in FIG. 1 also mounts a pressure fluid feed motor 34 and gear drive 36 having a rotary output means comprising a sprocket 38 drivably engaged with endless flexible drill feed means comprising a chain 40 which extends virtually the entire length of the mast assembly 10. The feed chain 40 has oppositely moving strands 41 and 42 supported at the lower end over a sprocket 43 and an idler sprocket 44, and at the upper end over an adjustably mounted sprocket 46 which is in turn rotatably supported by a chain adjustment block 48. The feed chain 40 lies in a plane essentially along the longitudinal centerline of the boxlike structure formed by the channel members 12 and 14, and is secured to the drill mounting slide 22 by a clamp 50, FIG. la, whereby the drill 20 is conveyed or fed along the mast assembly 10 at the same velocity as the strand 41.
Situated at the extreme upper end of the mast assembly 10 in the position illustrated in FIG. 1a is a grooved reel 52 rotatably mounted on a hub 54 which is secured to a frame 56. The frame 56 comprises a plate 58 (FIGS. 2 and 3) having grooves 60 and 62 slida'bly engageable with the flanged portions 64 and 66 of the channel members 12 and 14, respectively. The frame 56 also includes parallel bearing support plates 68 and 70 for a hose reel drive transmission generally designated by the numeral 72. The reel 52 forms positioning means for a plurality of flexible conductors comprising pressure fluid rotation motor hoses 74 and 76, a drill motor supply hose 78, and a drill hole cleansing fluid hose 80. The hoses 74, 76, 78 and 80 extend from a series of respective connectors 82, 84, 86 and 88 which are rigidly secured to the mast assembly 10 near its longitudinal midpoint (FIG. 1) by a bracket 90 and clamps 92 and 94. The flexible hoses are trained over the reel 52 whence they lead to the backhead 96 of the percussion drill motor 20 as may be seen in FIG. 5.
The hose reel 52 is desirably fed along the mast assembly 10 at a predetermined velocity less than the feed rate of the drill motor 20. For reasons to be explained later herein, the desired feed rate of the hose reel 52 is substantially one half the rate of travel or velocity of the strand 41 of the chain 40. This predetermined velocity of the hose reel 52 and supporting frame 56 is provided by the transmission 72 mounted on the frame 56 and engaged with both the strand 41 and the strand 42 of the feed chain 40.
Referring to FIG. la, FIG. 2 and FIG. 3 the transmission 72 includes a first shaft means 98 rotatively supported on bearings 100 and 102 housed in the respective bearing plates 68 and 70. The shaft 98 has integrally formed thereon a first drive wheel means comprising a toothed sprocket 104 engaged with the strand 42 of the chain 40. Also integral with the shaft 98 is a speed reduction wheel or sprocket 106 which is drivably interconnected with a second speed reduction sprocket 108 mounted on a second shaft means 110 by means comprising a chain 112. The shaft 110 is rotatively journaled parallel to shaft 98 in bearings 114 and 116 mounted in the plates 68 and 70. The shaft 110 additionally includes the drive sprocket 118 engaged with the strand 41 of the chain 40. The sprockets 106 and 108 are of predetermined differential diameters and the sprockets 104 and 118 are of equal diameter. The effective diameter for the determination of linear velocities for chain sprockets will be understood to be the pitch diameter of the sprock ets which will be referred to in determining velocity ratios rather than the number of teeth in respective sprockets.
An important consideration in the kinematics of chain drives is that the centerline of a chain is not at a uniform radius as the chain passes around the sprocket. This is particularly true for sprockets having small numbers of teeth. However, the variation in linear velocity decreases as the number of teeth increases and for ractical ap lications wherein minute variations are of no consequence, sprocket pitch diameter can be used for calculation of velocity ratios. Furthermore, it will be apparent to one of ordinary skill in mechanics of machinery that the chain and sprocket arrangement could be replaced by a variety of equivalent elements, for example, a toothed belt and cog wheel arrangement or a friction drive comprising belts and pulleys.
As previously mentioned the hose reel 52 is desirably fed along the mast 10 at a velocity less than the drill 20. Therefore, since the drill 20 is secured to the strand 41 of the chain 40 the velocity of the drill with respect to the mast 10 is equal to the velocity of the strand 41 with respect to the mast 10. However, the hose reel 52 and transmission 72 should travel with respect to the mast at one half the velocity of the drill. Such rate of travel of the reel 52 is accomplished by selecting the diameter of the sprocket 108 to be three times the diameter of the sprocket 106. An analysis of the respective velocities of the transmission components will verify such a choice of diameter ratio of the sprockets 108 and 106.
Referring to FIG. 4, angular velocities are denoted W and linear velocities V for the respective components of the transmission 72 shown schematically. For mathematical purposes counterclockwise angular velocities are positive and the direction of the velocity vector of strand 41 is positive. In the equations below subscript numerals are the reference characters of the respective components, and single subscripts denote velocities with respect to the mast assembly 10.
The angular velocities of sprockets 104 and 106 are equal since they are rigidly secured to shaft 98. The same relationship is true for sprockets 108 and 118 on shaft 110. However, sprocket 106 is connected to sprocket 108 by chain 112 therefore Sprockets 104 and 118 are fixed to frame 56 by means of bearing plates 68 and 70, therefore and chain 40 is endless, so
42= 41 (vi) Furthermore 11s 41= 11a 11a (vii) where r is the pitch radius of sprocket 118 (one half the pitch diameter) and As previously stated the diameters of sprockets 118 and 104 are equal, therefore 13y proper substitution of the above stated relationships 1nto Equation v in accordance with the algebraic sign convention of FIG. 4 the velocity of the transmission 72 may be expressed in terms of the velocity of strand 41 of the chain 40.
N-l-l (x) Therefore it can be seen that for a diameter ratio of the sprocket 108 to the sprocket 106 of N =3 the velocity of the transmission 72 and the attached hose reel 52 is one half the velocity of strand 41 with respect to the mast 10 and also therefore with respect to the drill 20.
It will be apparent to one skilled in the art in view of the foregoing disclosure that various diameter ratios of the sprocket 108 to the sprocket 106 or their equivalents could be employed in a transmission such as the embodiment shown and designated by the numeral 72 to give an extensive range of velocities of the transmission and attached structure relative to an endless conveyor means.
FIG. illustrates the mast assembly mounted on a crawler type undercarriage 120 in a vertical drilling position. Pressure fluid e.g. compressed air is supplied from a source, not shown, via a line oiler 122 and a main supply hose 124 to a control valve manifold 126 having a plurality of valves 127 providing for control of the drill feed, rotation, drill motor power, and hole cleansing fluid by an operator. The plural flexible conductor hoses can be partially seen in FIG. 5 leading from the manifold 126 to the intermediate connectors and clamp assembly and over the reel 52 to the drill motor backhead 96.
The hoses 74, 76, 78 and 80, FIG. 1a, are initially drawn moderately taut, so that they do not drag along the mast 10 when the latter is in the horizontal position, by positioning the drill motor 20 and the hose reel 52 at the extreme upper end of the mast assembly 10 as shown. The drill motor is then secured to the strand 41 of the chain by the clamp 50 and the hoses are adjusted for the desired tightness at the clamps 92 and 94, FIG. 1.
In typical operation as depicted in FIG. 5 as the drill motor 20 is fed along the mast 10 the reel 52 is fed at one half the speed of drill by the transmission unit 72. Due to the looped arrangement of the hoses 74, 76, 78 and 80 over the reel 52 they pay out off the reel at the same velocity as the drill 20 even though the reel is traveling at one half speed relative to the drill proper. When the feed motor 34 is reversed to retract the drill 20 and extension drill steel 30 from the hole, the reel 52 is also driven in the reverse direction, again at one half speed relative to the drill 20, to maintain the predetermined tension in the hoses 74, 76, 78 and 80.
What is claimed is:
1. In a drilling apparatus:
elongated drill support means;
drilLmotor means mounted on and linearly movable with respect to said support means;
feed means mounted on said support means and connected to said drill motor means for feeding said drill motor means reversibly along said support means; flexible conductor means having one end connected to said drill motor means and having another portion connected with respect to said support means;
the improvement comprising: positioning means linearly movable with respect to said support means for positioning said flexible conductor means with respect to said drill motor means, said positioning means including a transmission having at least one wheel means engaged with and rotatably driven by said feed means, said wheel means being linearly movable with respect to said sup-port means in the same direction as said drill motor means and in response to the operation of said feed means whereby said positioning means is moved with respect to said support means at a linear velocity less than said drill motor means.
2. The invention according to claim 1 wherein:
said feed means comprises endless flexible means forming two oppositely moving strands extending substantially the length of said support means, and said transmission means includes wheel means operatively engaged with both of said strands for driving said positioning means in the same direction as one of said strands at a predetermined linear velocity less than the linear velocity of said strand.
3. The invention according to claim 2 wherein:
said drill means is secured to one of said strands and is movable therewith along said support means, and said positioning means is driven along said support means at a predetermined linear velocity less than said drill means.
4. The invention according to claim 2 wherein:
said positioning means for said conductor means comprises a frame supporting said transmission means, first and second shaft means mounted on said frame; first drive wheel means on said first shaft means and engaged with one of said strands, second drive wheel means on said second shaft and engaged with said oppositely moving strand, and speed re duction means interconnecting said first and second drive wheel means operable to provide for driving said positioning means in the direction of one of said strands at a linear velocity less than said strand.
5. The invention according to claim 4 wherein:
said speed reduction means comprises first speed reduction wheel means mounted on said first shaft in nonrotatable relationship relative to said first drive wheel means, second speed reduction wheel means mounted on said second shaft in nonrotatable relationship relative to said second drive wheel, and means drivably interconnecting said first and second speed reduction wheel means.
6. The invention according to claim 5 wherein:
said first and second speed reduction wheels are of different diameter and said interconnecting means provides for driving said first drive wheel means at an angular velocity greater than said second drive wheel means in the ratio of the diameter of said second speed reduction wheel to the diameter of said first speed reduction wheel.
7. The invention according to claim 6 wherein:
said means drivably interconnecting said first and second speed reduction wheels comprises endless flexible means.
8. The invention according to claim 7 wherein:
said endless flexible means interconnecting said first and second speed reduction wheels comprises a chain and said speed reduction wheels comprise sprockets drivably engaged with said chain.
9. The invention according to claim 4 wherein:
the diameters of said first and second drive wheel means are equal.
10. The invention according to claim 4 wherein:
said endless flexible feed means com-prises a chain and said first and second drive wheel means comprise sprockets drivably engaged with said chain.
11. The invention according to claim 6 wherein:
the velocity of said positioning means with respect to said drill support means Vg can be expressed:
where V is the velocity of said strand to which said drill motor is secured with respect to the drill support means and N is the ratio of the diameters of said second speed reduction wheel to said first speed reduction wheel.
12. The invention according to claim 11 wherein: the value of N equals three.
13. Transmission means operable to be linearly driven along the path of an endless flexible conveyor having two oppositely moving strands, said transmission means to be driven in the direction of movement of one of said strands at a linear velocity less than the velocity of said one of said strand, and said transmission means being drivably engaged with both of said strands of said conveyor.
7 8 14. The invention according to claim 13 wherein: of one of said strands at a velocity less than the said transmission means comprises: velocity of said strand.
aframe; first drive wheel means rotatively mounted on said References Cited frame, and engaged with one of sald strands of 5 UNITED STATES PATENTS sa1d conveyor means,
2,730,332 l/1956 Hale l73--l47 second drive wheel means rotatively mounting on said frame, and gaged with said oppositely moving 6 t f d d a a u 15 s rando Sal conveyor means an 3,205,951 9/1965 Pyles 173 .16Q
speed reduction means operatively connected to 10 said first and second drive Wheel means whereby in response to said strands of said conveyor means JAMES LEPPINK Primary Exammer moving in opposite directions at a given velocity US. Cl. X.R. said speed reduction means operates to provide for l73160 moving said transmission means in the direction 15