US1239464A - Section-switch. - Google Patents

Description

H, w. DAVIS.

SECTION SWITCH.

APPLICATION FILED APR. 2?. 191's.

Patented Sept. 11, L917.

BY w Lmmw" ATTORNEY xxx I WITNESSES: & M v

NTED @TAE@ ATENT HARRY W. DAVIS, 01? SWTSSVALE, PENNSYLVANIA, ASSIGNOR OF ONE-HALF TO WILLIAM G. FROST, 01? EAST PITTSBURGH, PENNSYLVANIA.

SECTION-SWITCH.

Specification of Letters Patent.

Patented Sept. 11, 1%1'7.

Application filed April 27, 1915. Serial No. 24,234..

To all whom it may concern:

Be it known that I, HARRY W. DAVIS, a citizen of the United States, and a resident of Swissvale, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Section- Switches, of which the following is a specification.

My invention relates to section switches for electric trolley systems, and it has special reference to section switches for use in mine trolley lines, where the trolley condoctor is located near the roof of the mine and where it is customary to insert a sectionalizing switch in each of the branch conductors thatlead from the main trolley line into the side passages or headings.

The object of my invention is to provide a section switch of the above-indicated character that shall be simple and inexpensive use in mines and in other trolley systems where it may be necessary to cut a section of the line out of circuit, are usually made up of a large number of parts. They are therefore relatively expensive, especially in view of the fact that switches of this type are seldom operated, being only required for emergency use, as when a mine trolley becomes grounded by a fall of rockor the like. A further disadvantage of the existing forms of section switches is that the sectionalizing is usually accomplished by in serting a block of insulating material between the conducting end pieces or runners, and this insulation must generally be several inches in length, in order to provide sufficient creepage distance between the separated ends of the conductors. When such a device is in service, and the switch is closed, every motor that passes must lose its current for an appreciable interval, and

the sudden rush of current that follows when the insulating break is passed 1s a severe strain upon the motor. Furthermore, it sometimes happens that a heavily loaded car will stop with the trolley wheel resting against the insulating spacing block, and considerable inconvenience and loss of time are caused in again starting the car.

According to my present invention, I avoid all of the foregoing disadvantages, and, in addition, produce a device of extreme simplicity, in which two end pieces or runners are supported upon an insulating block and separated by a relatively short air gap, both sides of which are engaged by a trolley wheel passing the switch. The adjacent ends of the runners are preferably so modified as to provide a long creepage distance between the runners, which are electrically connected by means of a simple form of switch.

For a better understanding of my invention, reference may now be had to the accompanying drawing, which illustrates the preferred form of my invention. Two metallic end pieces or runners 1 and 2 are secured to the lower edge of a block 3, of wood or other suitable insulating material, by means of two short tap bolts 4 and 5 and two longer tap bolts 6 and 7. The bolts 4: and 5 are countersunk in the top of the block 3, in suitable holes which are fitted with plugs 8. The bolts 6 and 7 extend above the block 3 and are provided with fiat heads 9 and 10 that are perforated to receive a sliding switch rod 11 to which is attached a handle 12. The hole in the head 9 is slightly tapered in order that the rod 11 may be firmly seated in its contact-making position.

The outer ends of the runners 1 and 2 are provided with the usual openings 13, for receiving line wires 14: and 15, and set screws 16 are disposed in threaded holes transverse to the openings 13 for fastening the line conductors in place. It is to be noted that the trolley connections just described are formed integral with the runners, which is a feature of simplicity and compactness.

The inner ends of the runners 1 and 2 are separated by an air gap 17 which I prefer to make about 5; of an inch. wide, but which may be wider or narrower, if desired, without impairing the utility of the device. In order to increase the creepage distance between the runners, I cut away" the metal from the upper sides of the adjacent runner ends, as shown at 18. This arrangement does not seriously affect the rigidity of the .1 and 2 as much as possible, I prefer to cut away iportionsfrom their upper edges, as

:shown at 19, leaving the full thicknessat itlle 'pointswherethe fastening bolts 4:, 5, 6 :and 7 are'tapped in. By this means, I make *u-seof a minimum amount of metal, which 31S usually expensive brass, wlthout sacrifice --1ng rigidity or strength.

In order to reinforce the wooden block, transverse bolts and 21 may be passed through suitable openings near the endsof the block, and fastened in place by means of suitable washers and nuts. A hanger 22 -may 'be screwed to the top of the block 3,

and wires may be passed through holes in this hanger for the purpose of suspending the switch its operative position.

- The location of the sliding switch, on top of the insulating block 3, is a decided advantage,-since the switch rod and handle are protected from damage which may be caused by atrolley pole ifthe trolley wheelshould jump from the wire in the vicinity of the switch. Ifdesired, however, the switeh'may be placed upon :the side of the block, and

any other suitable switch may be substituted for the specific form which I have shown and described. I prefer theslidingitypeof switch for usein mines, becausethe trolley conductors are usually located so near the roof of the mine that little space is le'ft for j operating pivoted knife switches and the :like.

Inthenormal operation of the trolleyline in which my improved device is insertedythe ;sl1d1ng switch is closed, the rod llbeing in dthe posltlon shown. The bolts 6 and 7 ,to-

:gether with the switch rod '11 then form'a V shuntior jumper-connection aroundthe air gap 17, and trolley wheels, when they pass across the switch, will engage therunner on the farther side of the air gap before leav- 'ing' the other runner.

The current thereforepasses contlnuouslyto the motor, without the'interruptions and-consequent strains upon the moto'r which I have mentioned vabove. When it is necessary to cut out-of lci-rcuit the section of the line onthe-side of This construction I such :as are indica -cla1ms.

the switch away from the generator, the switch rod 11 is removedby means of the handle 12. The device then serves as an effective break in 'the conductor, since the long creepage distance described above prevents current from leaking from one line conductor to the other, and since the air .gap 17 prevents direct passage of current. No ipermanentrarccan be maintained across the air gap, even if a car should, cross it, for the outer endof theicut out sectio11+is generally :dead-ended, and itiis Jon'ly inecessary to throw off the controller .of tlIBlCZLI' .in:order to permanently extinguish anyaarc ithat unight :be struck across thegap.

:It is obvious that :the details 10f the struce ture which .1 have; shown and described may be variously modified by persons skilled in the E art without departing from :thespirit --and scope of my tinventiom andiit is therevsforesto beaunderstoodithatwno linntationsare to :be imposed 1113011 my invention :excep't ted .in the appended :I claimzas my inventionrl 3 i l '1. A section switch; 'for :trolley systems comprising a supporting .;block of insulataingamaterial, two'longitudinally a'linedesolid. -end pieces of conducting unateria'l attached :to the lower edge of the said block: and'hav- -ing. their :ad jace'nt: opposed. ends separated only by an .air gapsuiiiciently narrowto permita trolley \wheel to engage 'both of the said end pieces atonee and wide 1 enough :to

prevent arcing across the air gap'kunder -op- -v crating conditions, the said adjacent endsof the end pieces being cut away to a substantial extent :to provide an increased creepage path around =thesa1d a r gap, means for; attaching trolley conductorsfltoithej said end .;pieces, a plurality of {fasteners extending throughthesaid block and-serving to attach the said end pieces thereto, and a switch member adaptedto electrically connect and disconnectthe said endpieces.

2. A section switch for trolleysystems comprising a block. of insulating material, two longitudinally alined end pieces wattached to one edge of thesaid-block and "having their adjacent opposed endswseparated by an airgap, sufficiently irestricted to' permit a trolleywheeltokengageboth ofcthe saidend pieces at onceandisufiiciently wide to prevent arcing across-thegap under operating conditions, the outer ends of the" said end pieces being provided with means for .securing trolley conductors :thereto, -:means comprising fasteners extending through the said block and into the said end pieces, for

attaching the said end piecesrto :thesaid block, the said attaching zmeansvser vijng :also

as stationary switch contact -members,;and

a movable contact member adapted {to connect and LllSCOIlIlGGtillG. saidlstatiouargy .con-

. tact members. a I

3. A section switch for trolley systems comprising a supporting block of insulating material having downwardly converging sides, two longitudinally alined solid end pieces of conducting material attached to the narrowed lower edge of the said block and having their adjacent opposed ends separated by an air gap sufficiently narrow to permit a trolley wheel to engage both of the said end pieces at once and without shock, but wide enough to prevent arcing across the air gap under operating conditions, the said adjacent ends of the end pieces being cut away substantially parallel to their trolley-engaging surfaces to a substantial extent to provide an increased creepage path around the said air gap, a plurality of attaching screws extending through the said block and received in screw-threaded openings in the said end pieces, and a switch member adapted to electrically connect and disconnect certain of the said screws.

In testimony whereof I have hereunto subscribed my name this 26th day of April 1915.

HARRY W. DAVIS.

Witnesses:

B. B. HINES, R. D. BROWN.

Gopies of this patent may be obtained for five cents each, by addressing the Commissioner of Eatents, Washington, D. G.

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