US853348A - Machine-brake. - Google Patents

Description

PATENTED MAY 14, 1907.

-W. FBRRIS.

MACHINE BRAKE.

APPLIUATION FILED JULY l1 1906.

3 SHEETS-SHEET 1.

Ira/(41 1 far No. 853,348. PATENTED MAY 14, 1907.

- W. PERRIS.v

MACHINE BRAKL.

. APPLICATION FILED JULY 11, 1906.

3 SHEETS-SHEET 2.

WALTER FERRIS, or SOUTH MILWAUKEE, Wisconsin, AssIoNoh .TO THE BUCYRUS COMPANY, or SOUTH MILWAUKEE, WISCONSIN, A ooaPoRA- TION OF WISCONSIN.

Specification of Letters Patent.

MACHINE-BRAKE.

Patented May 14, 1907;

Application tiled July 11,1906. Serial No. 826,605, 7

To all whom it may concern.-

Be it known that I, WALTER FERms, a citizen of the'United States, residing at South Milwaukee, county of Milwaukee, State of Wisconsin, have invented certain new and useful Improvements in Machine-Brakes;

and I'do hereby-declare the following to be a full, clear, and exact descri tion of the invention, such as will enable ot are skilled in the art to which it appertains to make and use thesame. i

The invention relates to machine brakes, and has for its object to provide a band or strapbrake with means for operating the same to apply the brake against the turnin moment, in either direction, of the ban' wheel or shaft, and to automatically'reverse. the I ull on the band when the direction of the orce tending to turn the wheel or shaft reverses.

In the accompanying drawings, Figure 1 is a side elevation of a band or strap brake, involving the invention, applied to the shipperv shaft-of a steam shovel or excavator; Fig. 2 is an'enlargen cross section of the shaft end of the brake mechanism, showing the relation of. the parts when the brake is applied tothe wheel and the latter tends to turn away from the brake shaft; Fig. 3 is a similar view, showing the relation'of the parts when the force applied to the shaft of the band wheel tends to reverse the same; Figs. 4 and 5 are a side and plan view, respectively, of one end 01' the brake operating shaft; Fig. fiis an end power is adapted to be ap viewthereof; Fig. 7 1s a cross sectionon lines a-a of Fig. 5 Fig. 8 is a cross section on line bb of Fig. 5; Fig. 9.15 a cross section on line 0-0 of Fig. 5; e

As hereinbefore referredto, the invention relates to band brakes, and essentially to differential band brakes in which the braking lied for either atrection of rotation of thew eel or shaft to be braked. The band brakes in common use may be divided into two general classes,

1am and differential. In the plain band r lies, the heavy' ulling or anchor end is fas jned to a fixed support, entirely independent of the operating lever while the other-end, 'afterpassing around the brake heel, is attached tothe operating lever. In

- 'the differential hand brake, one end, which is called the lightp'ulling end, is attached to the is reached (the heavy brake lever at agreatei; distance or radius 7 from the axis offrevolution of the operating lever than the other orheavy pulling end.

As is well understood, when the handle of the operating lever is moved in the direction to set the brake, the to pull the light'end of-the brake band and to loosen the heavy pulling end thereof, but as the heavy pullin end is at a smaller radius fromtheaxis o L pulling end, the net-result is to tighten the brake band upon the brake wheel. A brake revolution than the light tendency of the lever is band of this type pulls much harder on one end than it does on the other, due to the accumulativeefl'eet of the friction between the rim of the brake-wheel and the brake band, beginning at a point where the light pulling end engages the brake wheel, or, in other words, where the wheel is passing out of contact with the. band.

The frictional force caused by the pressure of the band against the wheel, is added to the pull on the light end, and makes a heavier pull on the brake band just back of the point where the band begins to engage the wheel. Followingback along the brake band toward the other end, the frictional force is con stantly accumulating and increasing the tension in the band, so that when the other end pulin end), if the arc of contact is nearly t e full circumference,

the pull at that end of the band will be two and one-half or three times as great as itis on the light pulling end.

It will be apparent that. with the diiierential arrangement of the operating lever, this heavy pull acts to assist the operator in applying the brake, as it helps to throw the operating lever in the direction which the operator is trying to move'it. On the other hand, the light pulling end is opposing the action of the operator. As the pull on the heavy-end is from two to three times as great as the pull on the light end, it is necessary that the leverage on the heavy end should: be much shorter, in order that the operator may be obliged to supply a small amount of the required leverage of the heavy pull great, the brakebecomes-selfdecking, and

can only be d-isenga ed bly pulling the 0 p0 site direction It .w ill be evident, thereo'r'e,

fo'rce himself. Qbvious'ly,i fthe end is madetoo that the ordinary type of difierential brake can be effectively used in one direction. of ro-. i tation only, because if the brake wheel 15 re-' "versed ,1the heavy pull comes on the long leverage and opposes the action of the comes on t e short leverage.

ere brake, while the light pull This ob ect1on eration of the usual style of differential rake, is quite apparent when the brake .ator to ap ly t able 0 band is emplog ed in connection with the shig per steam es,

" shafts o and' the like.

shpvels, or dipper dre' In such machines, the bra es have two separate functions; first, when the dipper is suspended in the' air and is being wheels have to hold the weight of the hold the dipper into the hoisting rope pullin the arrangement of the brake operating sha I ingsz 3- per dredge, although, of

the fulcrum to the two ends of the r l typleof shaft which it isdesire 35. I

lowered toward the bottom,

multaneousl with the reversal of the direction of motion in the wheel to be braked.

ThlS may be conveniently accomplished bfy t and the appurtenant part shown in the draw" in which a'indicates the shaft which-is to be braked, and which, inthe present instance, is shown'as the shipper shaft of a dipcourse, itwill be understood that the invention ap lies to any to brake in the shaft, a is the e or direction. On

brake wheel 1?), surrounding which 'is the hrake band or straps wearing blocks d. The'ends of the brake J brake wheel and ban band are connected toitheoperating shaft 0, .at points on either side of the center thereof,

by any. suitable-:means, so that when the." shaft is rotated by 'the operator to aplpl broke, the endof the upper reach of t e ooselbraces or incloses the she ,so as to vtlielatter to have a limited move ment ni'the' beafl' g in 'a direction transverse to, the it. In the type of brake shown, it willbeiuriderstood that there are two brake" wheels',-" and," therefore, two bearings, but it will be a parent" tliath single and a single beann would inother cases be quite effective. bearing consists of abottom member 12,, provided with a section a which is.

u wardlyfacing lug t, The upper member oftheibearing is formed as a cap'portion o, fittingthe lower men' her'and seeuredthereto said portion 0.

band sifaced with the usual,

n1eans' of a the" and' moves downward and the e nd' of the lower w reach moves upward, thereby causing 'the' embrace the periphery of the f W i has} plied the; brake to counteract "this force I? generall .ec-' centric to. the shaft and'is provided wit an.

by the usual strap p, and having an inner surface likewise eccentric to the shaft, but disposed oppositely to the eccentric portion 8' 1n the lower bearing to constitute a recess t between the shaft and the inner surface ofv has a-lug s which faces therefore, oppositely to the lug t on the lower member shaft e, where the same passes throu h the bearing, is provided with two 0 'posite y disposed ugs c and j,which are a apted to 00- operate with the corresponding ln s and t on the bearing, under conditions tob e after moreparticularly referred to; These lugs are'formed as the terminations of gen-. erally' eccentric cam shaped portions 11 and 7", respectively, on the shaft. the bearin adjacent to the cooperating lugs 11 and s, rises member 0 is secured by a heayithjougholt 1-, which passes through the ganglion said cap member and the member n to thef-foundatlon, in order to resist the heavy strains imposed upon the cap member under certain conditions of operation. The outer end of theshafhbeyond the lug pordisposed with respiefiet e tions 1'. and j, is provided with a flange k, uponthe periphery of: which the operating lever h is secured by a suitable'ke "Beyond the flange It, toward the end, the. shaft is provided with nieansfor securing the respective ends of the :brake strap 0, which means may conveniently consist of a s' le recess 9 shapedto receive a cross pin in t e endof a tension boltm secured to the lower reach of-the band a, and the other side of the shaft is provided with two recesses f, f,which- Said up er member 0 also ownwardly and is,

herein- On the side of receive the bifurcated or double strap memher 0. attached band '0, and secure thesame. to the shaft by.

through-pin. g p {The operation of the apparatus, as hereinbefore' described, is substantially Assuming "that the force acting upon the shaft 0 tendsto revolve it in thedirection of the arrow shown in 1,and the operator ymovin thelever h lowenmember' o the s'tra comes thejtight side of th upper memberreceives only the pull of the operator and the lower member is, therefore, 1; e heavy pullin end of the brake, while the upper memberis the l' ht ulling end'. Under these conditions,*t cw eel band shaft a may be held abs lute ly stationary, or allowed: to rotate at the desired perfect control, and the shaft e occupies the relation'to its bearing'shdwn in Fig; 3, to wit, thelug has been moved down into engagement wlth the In t on the lower member of to the left, the or bonds then the bearing, and .t' e heavy pulling and of the band acting. with. big t. as a. fulcrum, assists the'operato'r to swing the shaft downward until the. lug io'ccupies a position considerto the-upper reach of the e brake, while use 5 as follows I ISO speed under simultaneousl ably below lug 3. Should the lturning mo-' ment or.force tending to rotate the shaft (1 and brake'wheel b he suddenly reversed, the relation of the shaft to its bearing will be instantly changed to that shown in Fig. 2, and the direction of the pull of the band will be automatically reversed. As the wheel 1; tends to move backward, the pull on the upper member of the band immediately draws the lug t on the shaft into engagement with lug s on the upper member 0 of the bearing, disenlglagin' lugs 7' and t, and maintaining t e bra 'ng girce between the band and the periphery of the Wheel throughout the engagement of said parts 7 without further action on the part of the operator. Should the shaft (2 a gain be subjected to a reversal, the brake shaft e will shift to its original position as shown in Fig. 3, andmaintain the full braking force on the wheel without requiring the necessity of furthcr manipulation b the operator. When it is desired to comp etely release the brake,

it will be understood that the lever it will be released, and the brake shaft 6 will move to an. intermediate position, permitting the band 0 to lie loosely about the wheel I).

Although the foregoing descri tion is directed more particularly tomac ine brakes of the differential type, 'i. e.,-brakes in which the res ective. ends of the strap or band are attac ed to the brake-lever or operating shaft in subh a manner that, the heavy pulling end assists the operator to apply the brake,it is to be understood that the invention is not limited to such differential brakes, but may also be employed in the brakes which are not differential. In the construction described such a case would occur if the co-operating lugs,

which act as ful erums, on the brake-shaftand its inclosing hearings, were placed'in line with-the points of attachment ofrthe ends of the brake-band .to thebrake-shaft. I It will thus be seen that the essence of'the herein described invention lies in a brake with shifting fulcrums which may, or may not be so arranged as to give difierential action. r

Having thus described my invention, what brake band,a brake lever w 'ch' is-nsed to' tighten the brake band upon the brake wheel, and means for automatically shifting the fulcrum of the brake leverwhen the directlon of rotation of the brake wheel is reversed, whereby the heavy pulling end and heavy pulling end and the light pullin relation to the fulcrum and to each other in either direction ofrotation.

pulling end v and the light pulling end shall ave the same 3. A differential band brake, comprising a brake band, a shaft to which the ends of the band. are connected to ap ly the brake, and a bearing in which said s aft is mounted to permit transverse movement of the shaft,

having co-operatmg the shaft and bearing means for automatical y shifting the fulcrum of the shaft when the direction of rotation of the brake wheel is reversed, whereby the shall have the same'relation to the fu crum end and to each other in either direction of rotation.

4. A diflerentialband brake, comprisin a brake band, a shaft to which the ends of t e band are connected to apply the brake, and a bearing in which said s aft is mounted to permit transverse movement of the shaft,

the shaft having oppositely disposed lugs and the bearing having cooperating lugs constituting alternate points of engagement or fulcrum, whereby the heavy pulling end and the light pullingend shall have the same relation to the fulcrum and to each other in either direction'of rotation.

5. -A differentialband brake,com rising a brake band, a shaft to which the en s of the band are connected to apply the brake in.

either direction, and a bearing in which the shaft is mounted'to permit a limited transverse movement of said shaft, the shaft having oppositely disposed eccentric lugs and the bearing. having coo crating shoulders adapted to be alternate y engaged by the corresponding lugs on the shaft to automatically shift the .fulcrum around which said shaft rotates when the direction of rotation of the band wheel is reversed.

In testimony whereof I'Iaffix my signature,

in'presence of two witnesses.

v WALTER FERRIS. Witnesses:

. RIDGELY FLE'roIlER, HARRY B. HAYDEN.

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