US3659655A

US3659655A - Feed controlling method and system

Info

Publication number: US3659655A
Application number: US42627A
Authority: US
Inventors: Laszlo Gyongyosi
Original assignee: Ingersoll Rand Co
Current assignee: Ingersoll Rand Co
Priority date: 1970-06-02
Filing date: 1970-06-02
Publication date: 1972-05-02
Anticipated expiration: 1989-05-02

Abstract

A drilling head and drill string is fed, or the feed is restrained, by a hydraulic-fluid-actuated piston. Hydraulic lines supplying and evacuating hydraulic fluid to and from the piston have gauges connected thereto to signal pressure conditions, in psi, at the piston. Scales calibrated in pounds are mounted adjacent to the gauges to signal, per machine and drill string and their characteristics, as well as the characteristics of the material being drilled, a proper correspondence between actual bit weight and an optimum feed pressure of fluid pressure assistance or restraint. A valve controls the hydraulic fluid supply and evacuation, selectively, to effect a holding back of the drill string, when its dead weight less the system''s internal resistance would produce excessive bit weight, a pulling down of the drill string when its dead weight less the system''s internal resistance would yield inadequate bit weight or pressure monitoring on a level just to offset the system''s internal resistance when the drill string weight alone would produce the optimum bit weight (i.e., zero hold-back). The gauges and scale advise the operator of the operational feed status that he might determine the requirements for holding back or pulling down the drill string. Valving at a fluid reservoir insures maintenance of a constant compensating pressure to one side of the piston at all times. This constant pressure, when minimum hold-back pressure is applied, provides a low pressure pull-down force to counteract the system''s internal resistance so zero hold-back can exist. (The system''s internal resistance is the sum of various stationary mechanical frictions and the minimum obtainable holdback pressure all acting against the development of a down motion of the drill string.) The compensating pressure also prevents possible cavitation.

Description

United States Patent I Gyongyosi [is] 3,659,655 51 May 2,1972

[54] FEED CONTROLLING METHOD AND SYSTEM [72] Inventor:

[73] Assignee: Ingersoll-Rand Company, New York, NY.

221 Filed: June 2,1970

21 Appl.No.: 42,627

Laszlo Gyongyosl, Clarksburg, W. Va.

Bullock ..173/9 173/152 x 464,182 12/1891 2,940,263 ,6/1960 Cudnohufsky FOREIGN PATENTS OR APPLICATIONS 634,421 3/1950 Great Britain ..173/9 Primary Examiner-Ernest R. Purser Attorney-Frank s. Troidl, David w. Tibbott and Bernard J.

Murphy [57] ABSTRACT A drilling head and drill string is fed, or the feed is restrained,

by a hydraulic-fluid-actuated piston. Hydraulic lines supplying and evacuating hydraulic fluid to and from the piston have gauges connected thereto to signal pressure conditions, in psi, at the piston. Scales calibrated in pounds are mounted adjacent to the gauges to, signal, per machine and drill string and their characteristics, as well as the characteristics of the material being drilled, a proper correspondence between actual bit weight and an optimum feed pressure of fluid pressure assistance or restraint. A valve controls the hydraulic fluid supply and evacuation, selectively, to effect a holding back of the drill string, when its dead weight less the system s internal resistance would produce excessive bit weight, a pulling down of the drill string when its dead weight less the system s internal resistance would yield inadequate bit weight or pressure monitoring on a level just to offset the systems internal resistance when the drill string weight alone would produce the optimum bit weight (i.e., zero hold-back). The gauges and scale advise the operator of the operational feed status that he might determine the'requirements for holding back or pulling down the drill string. Vaiving at a fluid reservoir insures main- -tenance of a constant compensating pressure to one side of the piston at all times. This constant pressure, when minimum hold-back pressure is applied, provides a low pressure pulldown force to counteract the system's internal resistance so zero hold-back can exist. (The systems internal resistance is the sum of various stationary mechanical frictions and the minimum obtainable hold-back pressure all acting against the development of a down motion of the drill string.) The compensating pressure also prevents possible cavitation.

14 Claims, 1 Drawing Figure FEED CONTROLLING METHOD AND SYSTEM it is already known in the art to provide drilling machine feed controlling systems which are operative in response to an enabling supply of pressured fluid, such systems being powered either by a fluid-actuated piston, or the like, but the known systems do not provide any visual indication of the fluid pressure subsisting in the system. Accordingly, the system operator has little opportunity for determining whether or not the feed pressure being applied is excessive or inadequate for the weight of the drill string in service. Also, in that the known systems do not provide a visual indication of the pressures subsisting in the feed system, the operator has no means for determining when to reduce or cut off the feed pressure and when, if he has such facility at his disposal, hydraulically to hold back the feed of the drill string.

It is an object of this invention, therefore, to teach a feed controlling system which is operative in response to an enabling supply of pressured fluid having means indicative of fluid pressures subsisting in the system.

It is another object of this invention to teach a feed controlling system, of the type noted, with means for providing pressured fluid to, and evacuating pressured fluidfrom, the system, including means automatically operative for maintaining not less than a prescribed level of the supply of pressured fluid in the system.

It is another object of the invention to teach a feed controlling system, of the type noted, with scale means, mounted adjacent to the pressure indicating means, having indicia inscribed thereon to establish a correspondence between said indicia and said pressure indication.

This invention has as another object the teaching of a method of feed control, for drilling machines having drill rod depending from a drilling head which is supported by, and movable relative to, a drill tower, and given fluid-actuable motor means, having opposed fluid-reacting surfaces, coupled to the drilling head for effecting movement thereof, comprising supplying a pressured fluid for actuation of said motor means; supplying a reservoir for receipt of fluid from said motor means; directing the supplied, pressured fluid, selectively, to one of said surfaces, and communicating another of said surfaces with the reservoir; and measuring the pressures of supplied fluid subsisting at said motor means.

As yet another object, this invention teaches the method just noted wherein the provisioning of pressured fluid includes always maintaining not less than a prescribed level of supply of pressured fluid to the motor means.

A feature of this invention comprises the disposition of pressure gauges in the hydraulic lines which supply or evacuate hydraulic fluid to and a feed-actuating piston, the gauges being provisioned to signal pressure conditions at the piston.

Another feature of this invention comprises the provisioning of scales calibrated in pounds, the scales being mounted adjacent to the pressure gauges to signal, per machine and drill string and their characteristics, as well as the characteristics of the material to be drilled, a proper correspondence between an actual bit weight and an optimum feed pressure of fluid assistance or restraint therefor. Accordingly, by noting a disparity between the psi rating on the gauging and the optimum feed in pounds as calibrated in the scales, an operator is then guided in deciding upon the provisioning of more or less hydraulic feed pressure to one side of the piston to vary the feed assistance or to the other side of the piston to vary the feed restraint).

Another feature of the invention comprises the provisioning of valving at a fluid reservoir which insures the maintenance of a prescribed level of compensating pressure at one side of the piston, at all times, to overcome the built-in internal resistances of the system which are significant enough that they could upset the feed motion in downward direction without this compensating pressure acting on the lower side of the piston when minimum restraining pressure is applied on the upper side of the piston. It also prevents cavitation.

Further objects and features of this invention will become more apparent by reference to the following description taken in conjunction with the accompanying figure which is a pictorial sketch, in a side elevational view, of a drilling machine which shows the tower with one of its mounting feet, the drilling head with a drill string depending therefrom, and the feed chains secured to the drilling head and tower and showing an actuating hydraulic piston operatively associated with a schematic diagram of an embodiment of the novel feed controlling system.

As shown in the figure a drill tower 10 comprises a frame 12 for supporting a drilling head 14 for sliding movement along vertical members of the frame. The frame 12 is supported upon the surface of the ground by a plurality of members 16 (only one being shown) having feet 18 at ends thereof. A drill string 20 depends from the drilling head 14 and the foremost drill rod thereon carries a drilling bit 22 for working penetration of the material being drilled.

The drilling head 14 carries anchors 24 at either sides thereof (only one being shown), and chains 26 are affixed to either ends of the anchors for effecting movement of the drilling head 14 relative to the tower 10. An idler pulley 28 is mounted to the drill tower 10 near the top thereof, and a second idler pulley 28 is mounted near the bottom of the drill tower, and the feed chains 26 are arranged about these pulleys. Further the feed chains 26 are arranged about a pair of movable idler pulleys 30, and thereafter the terminal end of each chain 26 is fixed to the drill tower at

points

32 and 34.

Idler pulleys 30 are carried rotatably in a sheave block 36 to which is fixed an arm or piston rod 38 which extends from a piston 40 disposed within a fluid chamber or cylinder 42. Cylinder 42 is pivotally fixed, at one end thereof, at point 44 to the drill tower. Cylinder 42 has two fluid ports 46 and 48'for admitting hydraulic fluid to the opposite sides of piston 40. First and

second fluid lines

50 and 52 are throughconnected with

ports

48 and 46, respectively, for supplying or evacuating hydraulic fluid to and from cylinder 42. Line 50 has first and

second terminal sections

54 and 56. So also, the second fluid line 52 has a given terminal section 58 and another terminal section 60.

Terminal section 54 provides a fluid connection between port 48 and a selector valve 62, and terminal section 56 provides a fluid connection between valve 62 and a slow feed hydraulicpump 64. The given terminal section 58 provides a fluid connection between port 46 and valve 62, whereas terminal section 60 provides a fluid connection between valve 62 and a pressure reducing valve 66. The slow" feed hydraulic pump 64 is supplied, by means of a line 68, from a fluid supply tank or reservoir 70. Pressure reducing valve 66 has a line 72 connected thereto which terminates in a reservoir 74. Pressure reducing valve 66 also has another line 76 connected thereto and extending to a terminal junction of lines 78.

Junction 78 interconnects a pair of

hydraulic lines

80 and 82 which are provided to supply enabling hydraulic fluid to a motor 84 which is used for ancillary equipment of the drilling machine. By way of example only, in this embodiment, motor 84 comprises a rotation motor for rotating the drill string. Accordingly, line 80, in cooperation with line 82, and another line 86, are coupled to rotation motor 84 through a rotation directional valve 88 to supply enabling hydraulic fluid from a rotation pump 90 to cause rotation of the motor in either the one or the alternate direction. Rotation pump 90 is supplied hydraulic fluid from a reservoir 92 by way of a hydraulic line 94. When'valve 88 is in the position illustrated rotation motor 84 revolves in a given direction. When directional valve 88 is displaced one position the hydraulic fluid is cut off from the rotation motor 84 and rotation of the drill string is halted. When the directional valve 88 is displaced a further position rotation motor 84 is turned in the alternate direction to (cause a reverse rotation of the drill string).

Lines

82 and 80, through junction 78, are through-connected with line 76 to provide the novel feed controlling system with a safety supply of hydraulic fluid-to maintain the feed controlling system at not less than a given level of fluid pressure. More of this feature will be explained subsequently.

It will be noted that

terminal sections

54 and 58 have pressure gauges throughconnected therewith. Pressure gauge 96, which is connected with terminal section 54, is identified as the hold-back gauge. The gauge 98 coupled to terminal section 58 is identified as the pull-down gauge. Gauges 96 and 98 are provided to signal the pressure conditions obtaining in cylinder 42, at opposite sides of the piston 40, so that the operator may determine visually the amount of fluid pressure being supplied through line 54 to hold back the drilling head, or the amount of fluid pressure being supplied through line 58 to pull down the drilling head 14, respectively.

Selector valve 62 is provisioned to effect a pulling down of the drilling 14 head and drill string 16, a holding back of the drilling head and string, depending upon the weight, the actual weight of the drill string together with the weight of the drilling head itself, or to effect neither a pulling down nor a holding back. As illustrated the system is arranged for effecting a pulling down of the drilling head 14 and string 16 because terminal section 56 is throughconnected, though selector valve 62, with terminal section 58. Accordingly, the slow feed pump 64 supplies a pressured volume of hydraulic fluid to the underside of piston 40 to move the piston upward. So also, terminal section 54 is connected, through valve 62, with terminal section 60 and from there, through pressure reducing valve 66, evacuates hydraulic fluid from the upper side of piston40 into reservoir 74. Therefore, the upper side of piston 40 has hydraulic, fluid evacuated therefrom, and the underside of piston 40 has pressured hydraulic fluid applied thereto to translate piston rod 38 and sheave block 36 upwardly which in turn causes anchors 24 and drilling head 14 to be moved downwardly in, and relative to, the drill tower 10. The drill string 20 depending from the drilling head is forceably fed, i.e., pulled down, into the material to be drilled.

Pressure reducing valve 66 is preset for a predetermined pressure. Should the pressure of hydraulic fluid in cylinder 42 at the upper side of piston 40 (due to the evacuation of fluid therefrom) fall below the preset pressure of valve 66, this valve automatically operates to throughconnect lines 76 with terminal section 60. This, in turn, insures that the upper side of piston 40 will not fall below the noted prescribed and preset pressure level of valve 66. Make up or safety hydraulic fluid, as required, will be supplied to the upper side of piston 40, from rotation pump 90 through line 82 (or line 80, depending upon the mode of rotation of motor 84).

The optimum feed pressure required for a particular drilling machine in a particular drilling operation, of course, is determined by the weight of the drilling head, such as drilling head 14, the weight of the drill string, such as'drill string 20, and the relative unyielding nature of the material being drilled. Other factors, of course, to a lesser degree, will enter into a determination of the feed pressure required in any given operation. That is, also to be considered are frictional losses in motion, the efficiency or configuration of the bit, and so on. However, more significantly we are concerned with the actual total weight of the drill string, drilling head, and bit. Accordingly, the invention teaches means for calibrating the novel feed controlling system for the particular machine and the operational conditions in which it is deployed. Scales 100 and 102, hold-back" and pull-down" scales, are arranged about gauges 96 and 98. They are provided with calibrated inscriptions or indicia representative of incremental weights in pounds.

For a particular drilling machine the drilling head will have a known, given weight. Let us say for purposes of illustration that thedrilling head, without a drill string, weighs 2,000 lbs. Now then, the operator will put the selector valve 62 in the hold back position, i.e., the position in which terminal sections56 and 54, and 58 and 60, respectively, are throughconnected. He will watch the pressure gauge 96 until it reaches that pressure indication at which the fluid pressure is reduced to the level where the drilling head 14 starts to slide downwardly. In drilling, the drilling head moves down, so weighing is done in the same direction. Whatever is the pressure indication, in psi on gauge 96, at that point the operator observes that inscription on the scale 100 at that point (ad- 5 jacent to the gauge indication) is 2,000 lbs. of weight. Next the operator can attach a drill rod and bit which together, let us say, weight 1,000 lbs. Again, the operator will put the selector valve 62 in the hold back position while the bit is off the ground (to supply pressured fluid to the upper side of piston 40) until the fluid pressure and volume is so reduced that the drilling head, drill rod and bit just begin to move down (pressure and weight is equalized). Again, the scale 100 indication, adjacent to the pressure reading shown with this condition, reads 3,000 lbs. in like manner the operator can determine, each time he adds a drill rod of known or unknown weight, the total weight hanging on the feed chain by observing the holdback scale for its corresponding inscriptions at the threshold of the down motion of the drill string.

In deep drilling operations, the operator will find that there is a weight of extended drill string which requires no hydraulic assistance to cause the drill to penetrate the material. So, the operator will neither hold back nor pull down the drilling head 14 and string 20. In this case he will put valve 62 in the holdback position and adjust pressure on gauge 96 until it corresponds with a minimum lbs. reading on scale 100. A full range hold-back, starting from 0 lbs, is not possible. This is due to the provisioning of a prescribed constant pressure condition in line 60 and at the upper side of piston 40, as noted in the text earlier. The constant pressure condition is provisioned by a preset pressure reducing valve 66, a pressure supply line 76 and an excess pressure relieving line 72. The combined function of these components is to maintain the constant pres sure condition in line 60 at all times.

It must be understood, however, that

components

66, 76, and 72 can be eliminated from the system without departing from the spirit of the invention if anywhere in the instant hydraulic system, or in ancillary systems, suitable constant pressure condition source can be found, or can be created, to which line 60 can be connected. Such sources could be the inlet portion of a supercharged pump, any pressurized return line, and the like.

Taking an arbitrary example, where the weight of the drill string 20 together with the drilling head 14 and bit 22 is 4,000 lbs., and the nature of the material being drilled is such that a proper bit weight feed is 2,000 lbs. the operator must put selector valve 62 in the hold-back" position until the gauge 96 registers a pressure which is in correspondence with an inscription signifying 2,000 lbs. on scale 100. Taking another example, if the weight of the drill string 20 together with the drilling head 14 and the bit weight 22 totals 4,000 lbs. but the nature of the material being drilled is such that a feed or an apparent bit weight of 30,000 lbs. must be applied, properly to penetrate the material, then the operator must put the selector valve 62 in the pull down position until gauge 98 reads a pressure corresponding to an inscription on scale 102 of 26,000 lbs.

An adjustable pressure relief valve 104 is coupled to section 56' by way of a line 106; valve 104 opens on reservoir 92. Valve 104 is adjustable to limit the pressure supplied to piston 40. Accordingly, where the hold-back pressure for a drill string of 4,000 lbs. requires a pressure of 2,000 lbs. on the upper side of piston 40, the adjustability of pressure relief valve 104 is used to limit the-fluid pressure (as read on gauge 96) so exactly 2,000 lbs. is registered on scale 100. The valve 104 is reset, for the optimum pull-down or hold-back feed pressure, each time a drill rod is added to drill string 20.

Pump 64 is identified as a slow feed" pump. It cooperates with a pump such as that of rotation pump to feed the drill string 20 while pump 90 is causing rotation thereof. However, any drilling machine requires a fast feed and retraction of the drill string, quickly to facilitate removal or addition of drill rods to the drill string. The volume and pressure of fluid provided through pump 64 is adequate and proper for drilling feed. However, for rod handling, it is more efficient to have a pump which can quickly raise and lower the drilling head 14 for this drill rod handling, and such a pump is provided in "fast feed pump 108.

Pump 108 is supplied by a reservoir supply 70' through a selector valve 62' to opposite sides of piston 40 by way of

lines

110 and 112. Before valve 62' is put in an enabling position it is, of course, necessary that

valves

88 and 62 be put in their blocked or neutral, non-communicating positions. These valves are shown independently operative only for simplification. However, it is of course quite feasible to couple or gang the

valves

62, 62' and 88 together so that it would be impossible for valve 62 to be put in either operative position unless valve 62 where in the blocked position-and the same would hold true for valve 88. This is a matter of engineering choice and will be obvious to those skilled in the art.

While I have described my invention in connection with a specific embodiment thereof it is to be clearly understood that this is done only by way of example and not as a limitation to the scope of my invention as set forth in the objects thereof and in the accompanying claims.

I claim:

1. A feed controlling system, for drilling machineshaving drill rod depending from a drilling head which is supported by, and movable relative to, a drill tower, and given motor means, having opposed fluid-reacting surfaces, coupled to the drilling head for effecting movement thereof comprising:

at least a first fluid supply and pump means for supplying pressured fluid to said motor means;

a fluid reservoir; and

means for selectively communicating said fluid supply and pump means and said reservoir, respectively, with said opposed surfaces to fluid-pressure one of said surfaces and to evacuate pressured fluid from another of said surfaces; wherein said latter means includes means for indicating the level of fluid pressure subsisting on at least one of said surfaces; and

graduated scale means, mounted in adjacency to said pressure indicating means, having weight indicia thereon in graduations to signal, in cooperation with said indicating means, an optimum feed condition for the system. Y 2. A feed controlling system, according to claim 1, further including:

means throughconnected with said reservoir automatically operative always to maintain not less than a prescribed level of supply of pressured-fluid to said motor means.

3. A feed controlling system, according to claim 2, wherein:

said communicating means including adjustable valve means for selectively controlling the communication of said fluid supply and pump means with said surfaces.

4. A feed controlling system, according to claim I, further including:

means throughconnecting with said reservoir automatically operative always to maintain not less than a prescribed level of fluid pressure to said motor means.

5. A feed controlling system, according to claim 4, wherein:

said pressured fluid maintaining means includes valving means automatically responsive to a given fluid pressure level to halt evacuation of fluid from said motor means.

6. A feed controlling system, according to claim 5, wherein:

said pressured fluid maintaining means further includes a second fluid supply and pump means, for supplying pressured fluid to ancillary motor means; and

said valving means includes means for through-connecting said second fluid supply and pump means with said given motor means.

7. A feed controlling system, according to claim 4, wherein:

said fluid communicating means includes a first conduit means, for conducting pressure fluid therethrough, having first and second terminal sections, said first terminal section thereof opening on one of said surfaces, and said second terminal section thereof opening on said first fluid supply and pump means;

a second conduit means, for conducting pressured fluid therethrough, having both a given and an other terminal section, said given terminal section thereof opening on the other of said surfaces, and the other terminal section thereof opening on said reservoir; and

valve means interposed between said first and second sections and also between said given and other terminal sections for accommodating fluid communication therebetween,

respectively,

for interrupting fluid communication therebetween, and

for throughcommunicating said second terminal section with said given terminal section and said first terminal section with said other tenninal section, respectively.

8. A feed controlling system, according to claim 7, wherein:

said valve means is selectively operative.

9. A feed controlling system, according to claim 7, wherein:

said indicating means comprise at least one fluid-pressure gauge in operative fluid-communication with at least one of said conduit means.

10. A feed controlling system, according to claim 1,

wherein: I

said communicating means include adjustable valve means for selectively controlling the communication of said fluid supply and pump means with said surfaces.

11. A method of feed control, for drilling machines having drill rod depending from a drilling head which is supported by, and movable relative to, a drill tower, and a given fluid-actuable motor means, having opposed fluid-reacting surfaces, coupled to the drilling head for effecting movement thereof, comprising the steps of:

supplying a pressured fluid for actuation of said motor means;

supplying a reservoir for receipt of fluid from said motor means;

directing the supplied, pressured fluid, selectively, to one of said surfaces, and communicating another of said surfaces with the supplied reservoir;

measuring the pressures of supplied fluid subsisting at said motor means;

noting a correlation of the measured fluid pressures at said motor means, which efiect perceptible movements of said drilling head and said drill rod, with the actual weights of said drilling head and drill rod of varying lengths; and

setting out weight-representative indicia, ona scale, to be able to correlate such movement-effective measured fluid pressures, per drilling head and drill rod weights, to said scale for reference purposes in effecting optimum feed per actual weights.

12. A method of feed control for drilling machines, according to claim 11, wherein:

said fluid supplying step includes the step of always maintaining not less than a prescribed level of supply of pressured fluid to said motor means.

13. A method of feed control for drilling machines, according to claim 11, further including the step of regulating the pressure of fluid supplied to said one surface, to limit the pressure to a value correlated to the actual weight of said drilling head and drill rod of a given length, when such actual weight alone will produce an optimum feed, to increase the pressure to a value which will produce an optimum feed when such actual weight is insufiicient to do so, and to reduce the pressure to a value which will produce an optimum feed when such actual weight is too excessive to do so.

14. A method of feed control for drilling machines, according to claim 13, wherein:

said pressures-measuring step comprises supplying a visual indication of pressure measurements; and further includes the step of juxtapositioning said scale with said visual indications so as to be able to determine the amount of pressure regulation eflected and to be effected, for said drilling head and drill rods of varying lengths, to achieve said optimum feed.

# i i i i

Claims

1. A feed controlling system, for drilling machines having drill rod depending from a drilling head which is supported by, and movable relative to, a drill tower, and given motor means, having opposed fluid-reacting surfaces, coupled to the drilling head for effecting movement thereof comprising: at least a first fluid supply and pump means for supplying pressured fluid to said motor means; a fluid reservoir; and means for selectively communicating said fluid supply and pump means and said reservoir, respectively, with said opposed surfaces to fluid-pressure one of said surfaces and to evacuate pressured fluid from another of said surfaces; wherein said latter means includes means for indicating the level of fluid pressure subsisting on at least one of said surfaces; and graduated scale means, mounted in adjacency to said pressure indicating means, having weight indicia thereon in graduations to signal, in cooperation with said indicating means, an optimum feed condition for the system.

2. A feed controlling system, according to claim 1, further including: means throughconnected with said reservoir automatically operative always to maintain not less than a prescribed level of supply of pressured-fluid to said motor means.

3. A feed controlling system, according to claim 2, wherein: said communicating means including adjustable valve means for selectively controlling the communication of said fluid supply and pump means with said surfaces.

4. A feed controlling system, according to claim 1, further including: means throughconnecting with said reservoir automatically operative always to maintain not less than a prescribed level of fluid pressure to said motor means.

5. A feed controlling system, according to claim 4, wherein: said pressured fluid maintaining means includes valving means automatically responsive to a given fluid pressure level to halt evacuation of fluid from said motor means.

6. A feed controlling system, according to claim 5, wherein: said pressured fluid maintaining means further includes a second fluid supply and pump means, for supplying pressured fluid to ancillary motor means; and said valving means includes means for through-connecting said second fluid supply and pump means with said given motor means.

7. A feed controlling system, according to claim 4, wherein: said fluid communicating means includes a first conduit means, for conducting pressure fluid therethrough, having first and second terminal sections, said first terminal section thereof opening on one of said surfaces, and said second terminal section thereof opening on said first fluid supply and pump means; a second conduit means, for conducting pressured fluid therethrough, having both a given and an other terminal sectiOn, said given terminal section thereof opening on the other of said surfaces, and the other terminal section thereof opening on said reservoir; and valve means interposed between said first and second sections and also between said given and other terminal sections for accommodating fluid communication therebetween, respectively, for interrupting fluid communication therebetween, and for throughcommunicating said second terminal section with said given terminal section and said first terminal section with said other terminal section, respectively.

8. A feed controlling system, according to claim 7, wherein: said valve means is selectively operative.

9. A feed controlling system, according to claim 7, wherein: said indicating means comprise at least one fluid-pressure gauge in operative fluid-communication with at least one of said conduit means.

10. A feed controlling system, according to claim 1, wherein: said communicating means include adjustable valve means for selectively controlling the communication of said fluid supply and pump means with said surfaces.

11. A method of feed control, for drilling machines having drill rod depending from a drilling head which is supported by, and movable relative to, a drill tower, and a given fluid-actuable motor means, having opposed fluid-reacting surfaces, coupled to the drilling head for effecting movement thereof, comprising the steps of: supplying a pressured fluid for actuation of said motor means; supplying a reservoir for receipt of fluid from said motor means; directing the supplied, pressured fluid, selectively, to one of said surfaces, and communicating another of said surfaces with the supplied reservoir; measuring the pressures of supplied fluid subsisting at said motor means; noting a correlation of the measured fluid pressures at said motor means, which effect perceptible movements of said drilling head and said drill rod, with the actual weights of said drilling head and drill rod of varying lengths; and setting out weight-representative indicia, on a scale, to be able to correlate such movement-effective measured fluid pressures, per drilling head and drill rod weights, to said scale for reference purposes in effecting optimum feed per actual weights.

12. A method of feed control for drilling machines, according to claim 11, wherein: said fluid supplying step includes the step of always maintaining not less than a prescribed level of supply of pressured fluid to said motor means.

13. A method of feed control for drilling machines, according to claim 11, further including the step of regulating the pressure of fluid supplied to said one surface, to limit the pressure to a value correlated to the actual weight of said drilling head and drill rod of a given length, when such actual weight alone will produce an optimum feed, to increase the pressure to a value which will produce an optimum feed when such actual weight is insufficient to do so, and to reduce the pressure to a value which will produce an optimum feed when such actual weight is too excessive to do so.

14. A method of feed control for drilling machines, according to claim 13, wherein: said pressures-measuring step comprises supplying a visual indication of pressure measurements; and further includes the step of juxtapositioning said scale with said visual indications so as to be able to determine the amount of pressure regulation effected and to be effected, for said drilling head and drill rods of varying lengths, to achieve said optimum feed.