US 2581721 A
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Description (OCR text may contain errors)
Jan. 8, 1952 A. H. SHERWOOD 2,581,721
WARNING DEVICE FOR AN on. WELL. DERRICK Filed Sept. 11. 1948 InVenior A/mond/i /lerwooo Patented Jan. 8, 1952" UN STATE PATENT OFFICE anmzr I Alm nd ll Sherwood,Whitfler,-Callf. I I llpllcationSeptembe-r 11, 1948. Serial No. use:
. .1 present i n. vices, and, more particularly, to warning devices for an-oil well derrick to indicate the approach oia traveling block to the top of a derrick. y
In the drillingof oil wells it is frequently necessary to handle extended lengths of- .drill pipe and for this purpose the usual derrick is provided with a traveling block which comprises a multiple pulley arrangement with a lifting hook to lift and'lower drill pipe.' In the usual arrangemerit, a motor driven draw works is provided on the floor of 'the drilling derrick and-hoisting cables are connected to the traveling block by a series of pulleys rotatably mounted on the crown block of the derrick. However, in the operation of the-draw works during the lifting of pipe, it is often necessary for-the operator of the draw works to bring the traveling block within a very short distance of the crown block of the derrick. Due to the weight and size of the traveling block and the fact that the draw works. operator is, generally located on the floor of the derrick, there is. a very serious danger of the traveling block striking the top of the derrick and damaging the equipment, or, as in a few cases, completely destroying the derrick with the consequent hazards of possibly injuring or killing the drill crew working on the floor of the derrick It is therefore an object of the present invention to provide a device for-warning the operator of the draw works of the approach of the traveling block to the crown-of.- the derrick.
It is a further object of-the invention to continuously warn the operator of the draw works when the traveling block is near the-top of the derrick.
Further objects and advantages oft-he invention will become apparent from the following description taken in conjunction with the accompanying drawing of a typical embodiment of the invention.
..'Ihe drawing is a somewhat diagrammatic representation of the alarm device as, applied to the draw'works for. an oil well derrick.
Referring to the drawing, 'a derrick I is shown diagrammatically mounted upon L'a' platform 2 which carries a rotary table 3. through which drill pipe 4 passes into and outofr the drill hole..
A crown block. 5 is provided at thetop of derrick I by means of a pair ofI-beams. The beams serve as-supporting means for ashaftand a. piuprises'a motor 'II and a -winch,l .2 iiiounted upon the platform 2. while'co'ntrollin'g' means'for the draw works In is not shown in the drawing, it
relates warning des 1 1'culin. (cl. 177-311 will'be' understoo'd'by those skilled in the art that controlling means will be provided at control panel I! for governing the movement of winch I2 to raise and lower traveling block I and pipe 4 through cable 8 and pulleys Ii.
As stated above, the operator of the draw works Ill is generally located on the platform 2 and is, therefore, not in a position to know exactly the location of traveling block I with reference to the top of the derrick, and due to the size and weight of traveling block 1 and the high rate of" speed with which it is moved on occasion, there is a very great danger that the draw works II! can pull cable 8 so that traveling block I is driven into contact with pulley and shaft arrangement 6 and either damage the crown block 5 or destroy the top of the derrick I. There is also the possibility of cable 8 breaking so that traveling block I and pipe 4'may be free to fall.
In order to reduce this hazard to the members of the drilling crew and to prevent damage to the equipment, I have provided a warning device in opposed relationship to the light source I4 so' that the light rays impinging upon cell I6 must pass through the center of the derrick whereby traveling block I may efiectivelyinterrupt" the flow of energy from light-source I4 to photocell I6.
While the light beam is shown vto traverse the top of the derrick perpendicular tothe traveling block shaft 1' it will be understood that photocell I6 and light source I4 may be located so that the light beam will be parallel to-shaft I. This location will depend upon where themaximum interrupting effect is achieved with minimum interference from cable 8.
A pair of wires I1 and- I 8 are connected between housing of photocell I6, however, for the sake of clarity in the description of the present apparatus the amplifier and relay are'shown within box IS in the drawing. Amplifier I9 is connected to a source of power, such as a volt source as shown, and relay H is adapted to connect the coil of time delay relay 24 to the 110 volt source In the usual arrangement,
cient. to cause extensive damage.
by completing the connection between line 25.
and line 26. The other side of the coil of time delay relay 24 is connected to the power source by means of line 21.
Time delay relay 24 is arranged to connect an audible signal means such as horn 28, as well as a visual signal alarm, such as a red light 29,
through lines 26 and 2'! when relay 2| is actuated- In addition to the signaling devices which may be operated by the interruption of the light beam, I have provided means for actuating the usual dynamatic brake used in this type of drilling apparatus. For this purpose, another relay 35' having its coil connected across lines 26 and 21 is adapted to close a set of contacts 36 and 31 connected in a control line for the brake.
In normal operation, the traveling block I will be below the beam'of light between the light source It and photocell l6. Under these conditions, amplifier I9 is arranged to maintain coil of the first relay in a de-energized condition. However, when traveling. block 1 interrupts the beam of light energy striking photocell l6, coil 20 of relay 2| is energized by amplifier I9 and the armature of relay 2] is picked 'up to operate lamp 29 and place the coil of time delay relay 24 across the'power source'through lines 25, 26 and 21. Since armature 30 of the time delay relay 24 is initially in contact with points 3| and 32,
horn 28 will be energized through lines 33 and 2'I,
thereby causing the horn to blow as soon as the light source is interrupted by the traveling block. Since in some cases it may be desirable to leave the traveling block at a point where the light beam is interrupted, provision is made to stop the horn 28 after a predetermined time, but it is still desirable to maintain a signal for the draw works operator to indicate the presence of the traveling block near the top of the derrick, and therefore lamp 29 is continuously energized.
By this arrangement, at least one of the signals will be energized in case of failure of the other upon initial interruption of the light beam. During this time, relay 2| is maintained in a closed position so that the warning devices are continuously. in operation. Relay 2| likewise operates relay 35, so that some control over the 1 stoppin of the draw works may be provided,
since the dynamatic brake may be applied to cause a slowing of the draw works I. While this application of the brake does not stop the draw works, it' will slow down the operation to such an extent that if the traveling block is driven to the crown block, the impact would not be sufll- When the traveling block is lowered so that the light beam again strikes photocell I6, coil 20 is de-energized, thereby opening the coil of the delay relay 24 By this invention the operator of the draw works is always apprised of the presence of the traveling block 1 in proximity to the top of the derrick l, since an audible signal is given when the traveling block first approaches the top of the derrick. If it is desirable to maintain the block near the top. a visual signal will still be present to indicate the danger of lifting the traveling block above its present position. In this way damage to the equipment or possible endangering of lives may be eliminated.
' it will'be obvious to those skilled in the art that variations and modifications may be made in this system, particularly with regard to the interconnection of the relay systems and the order in which the visual and audible signals are connected to the power source in response to the in-' relay 35 may be utilized to operate a solenoid valve to close a steam line when a steam engine drive is used in place of motor I. The same device may be used to ground the magnetos of 2 gas engine, to operate a magnetic clutch or to set an electric brake on any type of prime mover. Any of these operations may be obtained without interfering with the fundamental operations of the signaling equipment.
Such modifications and variations of the invention may be made without departing from the spirit and scope thereof, and I therefore intend to limit the invention only within the scope of the appended claim.
In combination, an oil well derrick having a draw works in its base for raising and lowering a traveling block within the derrick adapted to handle drill pipe, a braking means for said draw works, a light source mounted adjacent the top of said derrick, light directing means for concentrating said light source into a beam of light which passes through substantially the center of said derrick and across the vertical path of said traveling block, a photoelectric cell mounted on the opposite side of said derrick and adjacent the top thereof-to intercept said beam of light, amplifier means connected to said photoelectric cell responsive to the interruption of said light beam striking said photoelectric cell due to the interposition of said traveling block between said photoelectric cell and said light source, a visual alarm means and an audible alarm means, a time delay relay, another relay operable by said amplifier means to actuate said draw works braking means, said audible alarm means, and said time delay relay, said time delay relay actuating said audible alarm means for a predetermined time interval. ALMOND H. SHERWOOD.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 906,561 Reid Dec. 15, 1908 1,496,875 Field Jan. 13, 1922 1,913,699 Crago Nov. 5, 1929 2,366,152 Lauterbach Jan. 13, 1943 OTHER REFERENCES Electronics-June 1932, page 201; pg. 307 of Electronics, November 1933.