US1991690A - Slippage permitting clamp - Google Patents

Description

Feb. 19, 1935. b R. L. MccoY 1,991,690

SLIPPAGE PERMITTING CLAMP Filed Aug. 12, 1951 WW2-Q Patented Feb. 19, 1935 UNITED ls'rn'rllzls VLearnit' snIPrAcE BERMITTING CLAMP tRobert L. McCoy, Baltimore, Md., assignorfto Locke Insulator Corporation, Baltimore, Md.,

a corporation of Maryland Application August' 12, 1931, seriarNatssis v2 claims. 1 V(o1. aisfsl) I'I'he invention relates to clamps particularly designed for supporting the conductors of high tension transmission lines. Y y

It is well known that it is customary to support transmission line conductors by' means of strings of insulators suspended from towers located considerable distances apart. It 4frequently voccurs through breakage of the conductor or asthe result of an accumulation of ice or s leet on one or more clamps there are certain objections. "I-'o begink with-the conductor is notVPV of solid construction but comprises a core-about which arel wrapped or wound rods or wires usually of smaller gauge than the core and formed customarily of aluminum. When the usual type of releasing clamp opens upfthere is a certainy point at which the conductor will start to slip and itfrequently occurs that the break causes the exterior wires or rods to move relatively to the core,`resulting in what is commonly called bird caging. Furthermore in the use of the ordinary type of releasingclamp it is difficult to predetermine the exact holding power so that it may be known denitely at what degree of strain the clamp will open.

It is with the above facts in `view that I have devised the present invention which has forrits general object the provision of a conductor suspension clamp of suchV constructionthat its holding power is positively limited so that the cable may slip, without the clamp opening, when a certain predetermined number of pounds'of pressure or strain is exerted upon the conductor.

V.An important object of the invention is to provide a clamp of this character which may be formed'of what are commonly considered standard parts with the simple addition of means cooperating with the clamping bolts for limiting the Y shown, in the customary manner.

vFigure 1. -member 21 are ears 23 apertured for the passage which constitute necessary parts of a`releasing clamp ofjtheV opening type.. 'Y

`Yet anotherobject is to provide'a clamp of this fol-#FICE character v'which will be very simple and inexpent sive to make and assemble, positive in action, eincient and durable in service,v

provement in the art. v l

To-the attainment of the foregoing and other Aobjects and-advantages, the invention preferably consistsin the details of construction and the arrangement and combination of parts to Ybe hereinafter more fully described andvclaimed, and illustrated in the accompanying drawing in which: Y l

*Figurev 1 "is aside elevation of .a clamp con# structed in accordance with my invention, and

Figurev2 is a View half in end elevation andhalf in` section onthe line2-2 of Figure 1.

Referring more` particularly to the drawing I K `have shown: theV clamp as comprising a main lower or body member. 1G formed with a curvedseat 11 which extends longitudinally for the reception of the conductor,V not shown, the ends of the member Y10` being flaredor belled as indicatedat 12 vand the ends ofthe seat being correspondingly ared or longitudinally curved as at 13 for the purpose of avoiding bringing any bending strains on the conductor in the event of vibration thereof or what is known as dancing. At opposite sides the body member 10 is formed with laterallyv extend-V ing trunnions 14 with depending lips 15, the trun- `nions being received within circular holes 16 in links 17 adapted to be bolted at 18 `on to the lower end of a string of suspension insulators, not

The depending lip 15 prevents'accidental disengagement of the links from the trunnions but as an additional safeguard cotters 19 may be provided passing through the trunnions outwardly ofthe links. Furthermore the body member 10 is formed at opposite sides with pairs of laterally extending ears'20. Y

Cooperating with and located above the body memberlO is the movable clamping member 21 which is formed with a transversely curved seat 22 adaptedto contact with the conductor, this seat being moreover Vpreferably slightly longitudinally bowed as indicated by the dotted line in Projecting from opposite sides of the of clamping bolts 24 which pass through holes 25 in the ears 20 and'which are equipped with spring washers 26 and nuts 27. While the washers could be omitted they provide a certain re- 1,5. and a-general imj 2 l' y Y 1,991,690

wardly from their top sides and of course concen.

tric with the holes 25. Within these recesses are located bushings 29 of any suitable metal and which have 'outstanding ianges 30 overlying the tops of the ears 20 and engaged "by thev undersides of the ears 23.

When the clamp is assembled upon'the conductorin an obvious manner and when the boltsl 24 are inserted and the nuts 27 applied thereto and turned up tightly it is apparent that the ilanges 30 located between the ears 20 and 23 will limit the degree of clamping action exerted by the members Y1() and ,2 1'upon the conductor. It Ywill be noted that the seats'll and 22 are rather grad-Y ually curved, the curvature being of much greater radius than the radius of aconventional conductor. By virtue of this arrangement it is clear that the clamp may be used for supporting conductors of different diameters. When a larger conductor is to be used or when it is desired to limit still further therpressure exerted bythe clamping members the idea is to usebushings 29 having flanges 30 ofgreater thickness. In this way a clamp of one pattern suchk as that shown may vbe Vused in a large number of places and under widely varying circumstances by the simple expedient of having on hand a number ofinterchangeable bushings 29 with flanges 30 of difdiiferent ycircumstances as regards the sizeof the conductor to be ysupported and the degree of pressure lto be exerted thereon. The clamp is easily y assembled and applied and is of course used in exactly the same manner as any other of this type though it will be clear that when `the strain cn the conductor at either side of a tower from whichV the conductor is supported by means of this special clamp exceeds a certain predetermined degree the conductor may slip so that the unequal Y avoidingbringing excessive strainsupon the tow# er such as might cause damage thereto. It is thought from the above that the construction,

operation and advantages will be readily apparent vstrains at both sides may be equalized, thus l to one skilled-in the art without further explana` Y;

Whilel have shown and described the preferred embodiment ofthe invention, it should be understood thatthe disclosure -is merely an exemplication of the principles involved vas the right is reserved to make all such changes in the details Y v of construction as will widen the field of utility V and increase the adaptability of the device pro?" vided such changes constitute -no departure` from the spirit of the invention or the scopecffthe claims hereunto appended., v

Havingthus described the inventif-Jn,',lifclairn:

vmembersfcr securingthem-itogether in clamping engagement upon the conductor, andbushings surrounding said bolts and having anges located between the clamping members for limiting the holding power of the bolts. f 2

2. A conductor supportingV clampacomprising apairof clamping members -disposable upon-:op-i posite sides'of a conductor and equipped with suspension means, said members having laterally;v

y v Vv extending ears, bolts passing through vthe correa .Y

in clamping'engagement Vupon :thej conductor;`

lspending ears for holdingtheclampingmembersY l certain of saidears being-'formed v'vith'recesses;-V and bushings located within said-recesses and'.r .l through which thebolts pass,said bushings ,havl

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