US1004937A - Stay-bolt. - Google Patents

Description

G. S. THOMPSON. STAY BOLT.

s'r Es 'rn'r orrrcn GEORGE s. THOMPSON, or nocxnssm, DELAWARE, ASSIGNOR To THE FLEXIBLE BOLT L COMPANY, A CORPORATION or DELAWARE.

7 .fbidllwhom it may awm STAYLPBOLT.

Be it known thatLI, GEO GES. Tnorrrson,

a citizenofthe United/States, residing in 'I-Iockessin, county of Newcastle, and State ltl) bf'Delaware, havejnvented certain new and llseful'. Improvements .1n "Stay-Bolts, of

.aithiohihgfsillowing i'scas'pecification.

MZY improvements relate toxstaybolts having metal shanks of relatively high tensile strength provided with a head or heads of "1a softermetal. Whilen'ot restricted thereto, m staylbo'lt is designedmore' especially. for

' use between'thezfire boxes and the outer .shells of boilers, particularly locomotive boilers, in which, owing to the'inequality endvariability of'expansion of the fire loo'x pIatsaSQcoinpared. with the outer boiler shell,-thfe st ay bolts are subjected to severe lateral-strain. I

One ob-"ect-of my invention s to prov de means for fastening a stay .bolt of this chap acterto the boiler sheets named withoutv the necessity of riveting the ends, or where the riveting of 'one'en'dis desirable, to obviate the necessity of subjecting the shank to the thrust and 'impact oft-he riveting operation;

. Another object is to provide for the adjustment of the length of the bolt within itself, to compensate for slight variations of distance between the boiler sheets; also to provide means for testing the bolt to ascertain if it is in proper condition for service.

The invention'consi'sts in the specific constnuotionf and arrangement of parts hereinafter -described iand claimed',distinguishing, features' being the use of one or more taperedplug ends of relatively low tenslle strength-in conjunction with a shank of re'latively' high tensile strength; the formation of a take-up or compensating recess in one head; and in conjunction with the'latter feature, in the formation of a testing passage communicatlng wlth said take-up re- ,cess,',and--in the provision of means for effecting! the closure of said testing passage substantially as hereinafter set forth.

' In the accompanying drawings, Figure 1, is a central longitudinal section of my improved stay bolt, both ends 'of which are provided with soft heads capable of being riveted; Fig. 2, is a central longitudinal section'of a two piece stay bolt embodying my invention; Fig. 3,-a'central longitudinal section of the bolt illustrating a modification Specification a Letters Patent. l Application filed July 1, 1508. Serial No. 441,809.

Patented Oct. 3, 19 11.-

of structure; Fig. 4:, is a similar view showing' another. modification; Figl. 5, is a' detail of one end of the shank shown in Fig. 3.

As. is well known, the usual method of fasteningrigid stay bolts to boiler plates is to use a straightthreaded bolt and to peen or rivet'over the ends thereof to make tight joints with the boiler sheets. This riveting of the ends has heretofore involved the use of a bolt of comparatiyely low tensile strength, such as iron, copper or copper alloy, and even then if the male and female threads do not fit perfectly, or the riveting is' carelessly done, leaks areapt to occur. Furthermore, in order to attain the requisite degree of tensile strength the shanks of such bolts have heretofore been= 1i1adej: of comparatively large diameter. On the other hand, steel stay bolts have been used, and would be used generally were it not for the difficulty involved in making tight joints with'the'ends thereof and the boiler plates, Hencea steel shank pro vid'edwith ends that will insure tight joints alfords many"p -ac tical advantages which I attain by my structure of stay bolt. Since it is obvious that the smaller the diame ter of steel shank the greater will be its flexibility, and hence the greater" the lateral or bending strain it will stand, I am enabled to materiallyreduce the size and weight of the bolt and still retain the requisite degree of strength. This re duction in size' and weight also lessens the cost 'of the stay bolts; and they occupy less of the water space between the boiler sheets as compared with those heretofore used, thereby facilitating the circulation of water, and as a result, rendering the temperature of the parts more uniform and obviating excessive strain on the shanks of the bolts.

Theshank S is made preterably'of metal of comparatively high tensile strengthp and relatively small in diameter. Its inner end is formed with a male screw threads, for engagement with the female screw thread a, in the socket head A, which latter is formed also with an external thread a,'for engagement (preferably) with a threaded hole tapped in the the box plate F. The take-up recess a in the socket head A, is of sufiicicut depth to afford a margin of adjustment. of

length of bolt as a whole, to compensate for variations in distance between the fire box plate F and the shell B. My stay boltis,

thus adjustable within itself after the socket a.; 'plug insertion of a gage for the purpose of head A has been secured to the fire box )latc necessar since the o, 081

F, so that a shank S of uniform and prescribed length may be used within certain limits or variations of distance between plates.

The socket head A, may be provided with a test or indicator passage a, communicating with the take up recess a and closed by i p. This test passage a admits of ascertaining the extent ofpenetration of the threaded inner end .9, of the shank into] the socket head A, to determine for instance, the shank S, is screwed into the head suf tit iently to hold securely.

flVhen the socket head A is to be riveted to the plate I! as in Figs. 1 and 3, a dolly 92111 is introduced through the perforation b inlthe )late B to sustain said socket head 1 l 7 A, during the operat ion.

The test passage (1., may be closed by plugs '0f various terms. in Fig. 1, a screw plug is used, while in. Fig. 3, the plug is drivi a". some; to spread late-rally into a groove r a in the head. In Fig. 4., the test passage consist t a continuation of the take-up ,reeesr. closed by a threaded plug.

By making the test passage c and takeup recess of uniform diameter, with'a dontinuhus lemale thread for engagement with the male threads on tie/shank S, and by threading both ends of the latter, as shown in F 4;, both the outer head C aitd the socket head A, may be securely fixed and niadfe tight in the plates F andyB before inserted,--the latter being introduced through the socket A. In such manne'ifit'hc shank is not subjected to strains which it, otherwise would sustain and which are incitlent to the securing at the heads A and in the plates .F aiid G. By pro viding the inner end of the shank S with a telltale bore .9", the cracking or fracture of the shank S at this point would be indil 1 cated by the presence of water in the takeup reces (L to be ascertained by the removal of the plug 7).

I re or to make either one or both of ft I J the heads A, \i, ta pdnn externally, w1th male threads forengag; meat with correspondin tapering termne threads in the plates. has nl ig. i, the sot-hot; head A,

"consists of aplug tapered and threaded externall in a direction 0))0Slt0. to the an threaded external taper termed directly on the outer end of the shank 5.. a similar arrangement helng shown in Fig. t, excepting that the outer head (J is in this case ahead C is tapered. In this head is welded around the formed of a separate piece of metal softer thiilrithe shank S. In Fig. 3, only the outer case, also, the flattened or spread end 8 of the shank S.

'In the-two. piece form of bolt shown in 2; the riveting up of the ends is not I I l l tely tapered heads insure tight; joints. 7

It is to be noted that the shank S-is of to secure Letters Patent is,

1. The combination inf'a stay bolt of the character designated, of a threaded metal shank of relatively high tensile strength and small diameter formed with a tell-tale bore in-its inner end, an externally threaded socket head of less tensile strength formed with a female thread extending through said head for engagement with the male thread on the shank, and a screw plug engaging said female screw thread and closing the end of 'said head.

2. The combination in a stay belt of the character designated, of a threaded metal shank of relatively high tensile strength and "small diameter, and an externally threaded tapering socket head of less tensile strength formed with a female thread for engagement with the male thread of the shank,;and with a takeup recess, with a test passage, and with a plug for closing said test passage.

3. The combination of a stay bolt of the character designated, a threaded metal shank of relatively high tensile strength and small diameter, formed with a bore in its inner end, an externally threaded tapering socket head of less tensile strength, formed with a/temale thread for engagement with the'male thread on the. shank and extending through said head, and a screw plug. engaging said female screw thread and closing the end of said head. 4-. The con'ibination of two oppositely dis,- posed boiler plates and a joining device consisting of a head member of relatively low tensile strength screwed into an opening in one of said oppositely disposed plates, and a shank member of material ofv relatively high tensile strength removably engaging at one end one of said oppositely disposed boiler plates and removaliily engaging at its opposite .end the aforesaid head member carried in the opposite of the said two boiler plates; substantially as described.

The combination in a stay bolt'of the character designated, of a threaded metal shank of relatively high tensile strength and small diameter and an externally threaded socket head formed with a female screw thread extending through the head for engaging the male screw thread on the shank tell-tale' shank of relatively high tensile strength and a small diameter formed with a tell-tale.

-". gagement with the threaded shank and with the shell of the boiler and a screw plug adapted to engage the internal thread of the plug and closing the outer end of the v nated, of a threaded metal shank et relatively high tensile strength and t small diameter, and an externally threaded I tapering socket head of less tensil a strength 1 formed with a, telltale screw thread engaging 1 with the male screw thread at the shank and extending through said head and'a l screw plug engaging said female screw 1 thread and closing the end of said head.

l l itnesses GEO. M. B'lu'r'r,

l 1 GEORGE S. TIIOMPSON.

l l). \l. Gunmen.

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