US 2131291 A
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s; v'fAUsT SIGNAL SYSTEM FOR EHCAYATORS Filed June 1S, 1936 worm INV ENTOR. Ek wiyr fram??? QQ/@Wm ATTORNEY.
Patented Sept. 27, i933 SIGNAL SYSTEM FR EXCAVATORS Charles I. Mausi, Summit, N. 5.
Shis invention pertains, generally, to electiicn signal systems, and the invention has reference. more-particularly, to n novel signal system adepteri for use in connection with excavators used 5. icr underground wort: und particularly in excarating in earth and ft? The function of this invention is to indicate y signal to the operator Whenever the tool mrt of me excavating machine approaches or contacts lith existing services in itl the earth or till, 'whereby the operator may telco proper precautions to rrotcct such services from injury.
The Word service or service member, as herein contained. is intended to apply to any .existing l5' pipe, conduit. duct, 'frire or cable in the earth or ll usciul .for such services :is electricity. telcphone, telegraph. tretlic signal systems, tire alarm systems. police communication systems, gas. water. trolley return feeds, sewers and drains. 9.o' The v.verd machine es herein contained shall be understood to apply to any machinery'which is used for excavating. digging. scratching. plowing, boring, pushing er tunneling in earth end fill. The word machine simil also be understood 25 to include such machinery :is lndder type dltchers. crawler and wheel mounted types of cranes. with shovels, drag line scoops, clamp shell buckets. orange peel buckets. pull scoop buckets.- backhoe buckets.` trench hoe buckets, post, hole diggers, 3G boring machines, tunneling machines and pushing machines. The 'word tool es herein contained simil be understood to apply to that part oi any machine which does the actual wort: in the earth :md till, such as the boom and bucket, boom and :s shovel, or shaft and auger.
In towns and municipalities, many servicesl generally exist under streets, walks and other plots of ground. The exact positions, directions. slopes, bends and connections oi such services 4g in most cases are not accurately known, as in some instances only general locations have been recorded and in others. rccrrds and land marks have been lost. For numerous reasons such loealities must be excavated, etc., for new services, i5v extensions, repairs, changes or replacements. Hcretoi'ore, machines for such work have been wry limited in application due to the hazard of damaging existing services or due to slow'. high cost operation of the machines to avoid injuring 5 such services, 'This invention will hermit much broader application of machines for underground work where underground services may he encountered. Some types oi mxchincs can be utillzed to great advantage around services without 5 datuioge thereto, providing the operator is given an indication oi' the approach to and contact `with such services.
One object of this invention is to provide signal means for suitably indicating or signaling to the operator of the: 'nnchine the relative nearness 5 of a service the tool approaches the saine. thereby pcrznltrg fairly rapid ori-erationl oi the machine uni." t 1e tool gets very close to the service, whereupon the operator een exercise caution :ind reduce speed. IG
Another object. of this` invention is to permit on adjustment if the signal system so that the same bt-lfzns th r'z'icate et n greater or lesser dis tance oi the tooi no the. services, whichever is de sircd. tl.: said slcnsl system being ndapcd to inl5 cil-cate relative distances oi the tool to the services hy the automatic change of sound volume, frequency or visual indication.
Still another object o' this invention is to provide si novel excavator signal system that docs not 2 cause the operator to detract his attention irorn the operation of the tool. for whether the signal. device be audible or visual. or n combination thereof. the said device is located close to und in un advantageous position for the operator. 9,5 thus preventing foreign sounds such as created by the machine. trucks, trolley cnrs, trains. ctc., from interfering with the signals.
Another obect ci this invention lies in the provision oi n novel excavator signal system that 1 30 is oi simple construction and is reliable and economical in operation. the seid system being adapted to be readily tested i'or service signal at any time to be sure that all parts are ready for operation. 35
till another object of this invention is to prvide for the automatic supervision of the cornplete circuit by'way of a constant visual or audible indication.
Other objects and advantages will become np- 40' parent from the specification, taken in conriec tion with the accompanying drawing wherein the invention is embodied in denite form. l
Fig. i is a schematic view illustrating anexcarotor in use and equipped with the novel signal 45 system of this invention. i
Fig. 2 is a wiring diagram o one form of signal system of this invention` 3 is o wiring diagram of a slightly modifie form of the invention, and ,50
Fig. iis a wiring diagram illustrating the preierxed form of the invention.
` Similar chnmctcrs of reierer'zc are employed in the above views to indicate corresponding parts. L g de .f, .......rn .Ji-i..
:zoomer u fier; however, other parts of the circuit can he used for either volume or ireouency control. such as the control connected in the microphone cir cuit. heater circuit, or generator grid circuit. Many radio hook-ups can be'made with and without. tube amplification and with more stages of amplification to suit the requirements.
In Fig. 4. G and ii are a source of electrical energy such as three batteries consisting of 6 volts, 223 volts. together designated as 6, and 221]; vclts, designated B', or a Gvelt storage battery vdth a motor generatorset [er voltage conversion may be used. '.vhile 'l is a tut-oil switchfor thc source oi energy. AQOOchm rheostattiis used for simulating the changes oi earth resistance when adjusting the signal device for the proper signal to the -desired earth resistance. Icheostat. 8 contains an open-circuit point and the rheostat is normally st: on this open-circuit position. A microphone fr loud speaker or other sound devic:I such es a bell 8 for conversion of electrical energy' into an audible signal, or a set of relays and lamp.; for conversion of electrical energy into a visible signal may be employed in lieu oi Q. A ground connection ii oi the control circuit to the metallic frame of the machine is used, a part oi the frame which nas good metallic connection with the tool being employed. The earth part of the control circuit is designated i2 and separat-es the tool from thenear-by services. A connection oi' the control circuit to one or more parts oi a service system, such as e fire hydrant i? or gas or water pipe in a building or street. is crzztioged. A conventional A. C. generator such as an audio oscillator 2 or a power driven generator is used for supplying a. step-down transiormer 23 in the control circuit vwith an audio frequency signal. plies current through ground l2 to e. step-up transformer 29 in the signal control circuit. The output of transformer 2B is supplied to a conventional type ot audio ampliiier 3Q consisting of one or more stages ci ampliiication and having the signal device 9 in the plate circuit thereof. Resistors 3i and S2 serve for adjusting the sig nel volume to suit the desired indication of greater or leas distance of soil separation between the tool and the services.
When the tool of the machine is not in the earth. there is enough leakage in the radio circuit te operate the device 9 or loud speaker faintly. When the tool contacts with the soil the audibiiity increases slightly. Under the latter condition, the operator is automatically given supervisory indication that 1li connections are complete and that the stt is functioning. This feature is very important, as occasionally the wire connecting the signal device t) the service systern'becomes broken or disconnected. As the tool approaches a service, the signal gets louder and louder so that., in use, the operator can tell just how near he is to a service, and hence avoid striking the same with the tool.
As many changes could be made in the above construction and many apparently widely difierent. embodiments of this invention Could be marie without; departing from the scope thereof. it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.
What is claimed is:
I. in combination with an excavator having a digging toni, a signal system for notifying the operator when the tool approaches a. service Transformer 28 sup-v member and the ncarness of approach, comprisine asigna! device and a circuit for controlling me operation oi the signal device, said circuit including a source oi current, the excavator dlgging tool, th variable resistance oi the layer of earth between the digging tool and the service.
member. and the service member, the constants of the circuit and the character of the signal de vice being such that the signal device is eiIectively operated at a predetermined distance of approach or' the digging tool i the service member and is operated with increased intensity upon further approach.
2. In combination with an excavator having a digging tool, a signal system for notifying the operator when the tocl approaches a. service member, thereby giving the operator ample warning to prevent the tool from contacting a service t member and enabling the maximum digging by an excavator without musing;r damage to rnetalllc service members, the .said signal system comprising a signal device and a. circuit for controlling the operation oi' the sipnal device, the said circuit including a source of electrical current, the excavator digging tool, the variable resistance oi the layers of earth and/or illl between the digging tool und a service member, the return connection between the said signal device and a part oi the said metallic service member, and the electrical connection from the said signal device to the tool. the constants of the circuit and the characteristics of the signal device beine such that the signal device is eiectlvcly operated at various predetermined distances of approach of the tool to the service member, the signal device operating continuously with increased intensity oi signal as the tool moves closer to the service In mber, thereby signifying to the operator that the tool is working in a caution zone that may extend from a few inches to within a ien' feet from the service member, the range of the caution zone being predetermined by the operator, the signal device having: e means of adjustment or the desired range of th zone to suit the type and condition or the earth or ll and to suit the type and speed of the excavator.
3. In a sien-ul syst-ern for excavators having;` an earth excavating ical, s. thermionlc oscillator for producing an audio frequency signal voltage, a circuit including a transformer energized by said signal voltage, said circuit including the excavator tool, a. service member end the earth extending between said tool and the service morn bei', together with an output transformer, and an audio signal device fed from said circuit outout transformer. the constants of the circuit and the character of the signal device being such that the signal is eilectively operated at a predetermined distance of approach of the digging tool to the service member and is operated with increased intensity upon further approach.
4. In a. signal system for excavators having an earth excavating -tool, generating means for producing an audio icequency signal voltage, a. circuit energized by sait; signal voltage, said circuit including1 the excavator tool, a service member and the earth extending between said tool and the service member. and an audio'signal dcvice controlled from said circuit, the constants f the circuit :ni the character of the signal device being such that the signal is efiecively operated at a ph determined distance of approach oi the digging ooi to the service member and is operated with increased intensity upon further approach.
5. In combination with an excavator having e. digging tool. of a signal system for notifying 5 the operator by means oi a steadily increasing intenses' oi signal when the tool approaches toward a service member, said signal syst-2in comprisng a signal device, means connecting: one
side oi said signal device electrically' to said' tool,
l a source oi current for said signal device, means for detachably connecting the other side oi said signal device throufh sind source of current to a service member, a conductor for connecting said one side oi said signal device also to said service l5 member, and a pilot lamp connected in said con# ductor'due to the connection oi said one side oi said signal device through said tool and the earth to the service member in parallel with said lamp.
2O G. In a sicnzil system for excavators, a source` of electrical energy, a signal circuit connected to be energized therefrom, a signal device included in a part oi said circuit, said circuit also including conducting: means for connection to a service member md additional conducting means for connection to the tool of the excavator. the earth between the tool and the service member also beine, included in said circuit. the current in signal circuit being gradually increased as said tool approaches the service member, whereby the signal intensity oi said signal de. vice also gradually increases, the signal commencing audible operation when the tool is at a substantially predetermined distance from the service member..
7. In a signal system for excavators, a source of electrical energy, a signal circuit -including means for producing electrical alternaiions supplied from said source. said circuit having a por- 'iil tion thereof including conducting means for connection to a service xneinlier, together with a connection to the toot of the excavator, the earth between the tool and the service member being included in said circuit portion, said portion of said circuit being energized .from said means for producing electrical alternations, and a sin nai device coni-rolled from said circuit portion. the constants oi the circuit and the character of the signal device being such that the signal is eiectively operated at a predetermined distance of approach oi the digging tool to the service member and is operated with increased intensiLr upon further approach.
8. In combination with an excavator having a digcing tool, of a signal system for notifying the operator when the tool approaches a. buried service member, said signal system comprising a pair oi signal devices having differing operating characteristics, circuit means for electrically connecting said signal devices to said tool, a source of current for said signal devices, und means for electrically connecting,7 said signal devices to a service member, the earth between said tool and the service member completing the circuit (i5 for said signal devices, relay means for vrirying the Een of current through raid .'gmi devices to cause the indication of one oi said devices to predominate when the tool is reli'itivcly remote from n service member, the signal output of said device coniinuinr u'iih increased intcnsiy upon further approach of the tool until tlze Latter is at a predetermined distance from. the service member', vv .'hcreupon the signal output oi said one device falls cil sharply and the signal output. of the other device prcdorninntes when the ooi continues to advance relatively close to the ser vice member.
9. In combination vwith an excavator having a digging tool, oi a signal systeml for notifying the operator when the tool approaches a buried service member, said signal system comprising a pair of signal devices o diiicring operating characteristics, a series multiple circuit having said signal devices respectively connected in the respec ve parallel legs theresf, a source oi current connected in the series portion of said circuit, said circuit series portion having one side thereof arranged for removable connection to a service member and the other side thereof connected to said digging tool, the earth between said tool and the service member completing the circuit for said signal devices, the constants of the circuit and the character oi' the signal de vices being such that the signal devices are eiiectiveiy operated at predetermined distances of approach oi the digging tool to the service .inember, said signal devices operai-ing vwith dzierential intensities upon further approach.
i0. In combination with an excavator having s diggin@ tool, of a signal system for notifying ie operator when the toolapproaches a buried service member, sai-:l signal system comprising a.
pair of signal devices, a series multiple circuit having said signal devices respectively connected in the respective parallel legs thcreot', a source of current connected in the series portion ci' said circuit, said circuit series portion having eine side thereof arranged Ior removable connection to a service member and theother side thereof connected to said digging tool, resist-ors arranged .to be included in said parallel legs, and relay means, 'responsive to the current-Serv in the series portion 'oi said circuit, and operating, when the current therethrough reaches a predetermined value, for sliunting a resistorof one of said legs while inserting a resistor of the other leg therein.
11. in combination with an excavator having a digging tool, of a signal system ier Vnotifying the operator vwhen the trol approaches a hidden service member, said signal system comprising an oscillator, circuit means energized from said oscillator, said circuit means including said digging tool and an available service member in series therein, the earth between-said digging tool and the service member constituting a part of said circuit means, thei'mionic amplier controlled from the Ai C. ousput of said circuit means, and a signal device connected in the output oi said amplier.
12. In combination with an excavator having a digging tool, of a signal syst-em for notifying the operator when the too: rtg' coaches a hidden service member, said sional system comprising an audio oscillator, circuit-means including said digging tool, un available service member and the intervening earth in `series therein, a transformer for supplying energy from said oscillator to said circuit means, an amplifier having an audible signal device in the output thereof. and s transformer for coupling the A. C'. output of said circuit means to said amplifier.
CHARLES I. MAUST.