US1581839A

US1581839A - Apparatus for testing hardness of firm bodies

Info

Publication number: US1581839A
Application number: US621388A
Authority: US
Inventors: Dahlqvist Carl Edvard
Original assignee: Individual
Current assignee: Individual
Priority date: 1923-02-26
Filing date: 1923-02-26
Publication date: 1926-04-20
Anticipated expiration: 1943-04-20

Description

April 20 1926.

` C. E. DAHLQVIST APPARATUS FOR TESTING HARDNESS OF lBODIES Filed Feb. 25, 1925 Patented Apr. 20, 1926. i

UNITED STATES assiste CARL EDVARD DAHLevrsfr, on srooxnoriiu, swnnnri.

APPAaArUs Foa 'rns'riive Hannunss or Finir BODIES. A

,y vApplication filed February 26, 1923. Serial No. 621,388.

fo all whom; it may concern.

Be 1t known that I, CARL EnvARn DAHL- Qvrs'r, engineer, a subJect ofthe Kingl of Swed-en, and resident of Stockholm, in the county of Stockholm, Sweden, have invented certain new and useful Improvements in ApparatusV for Testingl Hardness of Firm Bodies, of which the following is a specification. e Thel present' invention relates to implements for testing `the degree ofhardness or resistance of solid materials, such lasmetals, etc.; and it embodies certainy improvements whereby the spring which operates the impact element may be cocked or set'without pressing the implement against the object tobe` tested, and whereby glancing or ineffective strokes of the impact element may be avoided, all as hereinafter fully described.

One form rof the invention is illustrated, by wav of example, in the accompanying drawing, wherein';-` v t Figure l is a longitudinal section of the completeimplement; i f Y Fig. k2 is a plan viewl of a lockfnut which is used on the impact element;

Fig. 3 is a part-sectional side elevation of a device for cooking the operating spring;

Figa 'ifs a bottom plan'view of an attachment for guiding and holding the impact element; 'f iV FigL 5 isalongitudinal section thereof on line A-A, Fig. 4; and y Fig., 6 is a top plan view of said attachment;

Referring 'more particularl to the drawing, 2 indicates thetubular s ellor case of the implement, and 1 a cap or cover removably threaded into thei1p.per endl of the-case andv provided withaj `central opening 27. The lowerend wall 19 ofthe case is made with a perfectly -flat or plane outer face, for a purpose subsequently explained, and like- Wise has` an opening at its center. Withinthe case 2, there is-slidably arranged an impact element 16 inthe form of a rod or plunger having its upper portion threaded, as shown, and provided. immediately abovesuch threaded portionwith a transverse `opening '3; thev 'lower end of the rod terminatin in a rounded'or-y pointed member 18 whic i is disposed. exactly` in line with the opening in the bottom wall 19 of the case. lock-nut 4 is mounted on the threaded'. upper portion of the rod and is split radiallyat 5 (Fig. 2) ,the two legs produced Aby the Vsplit beingprovided with threadedscrew-holes to receive a clamping vscrew or bolt 6 which, when tightened, willv serve to lock the nut in adjusted position upon the rod, as will be understood.

The impact rod is adapted to slide longitudinally within its case, and'is guided during such movement by upper `and lower bear-

V ings

7 and 20, the latter of which consists ymerely of4 a transverse partition having a central opening. vThe upper bearing is in@ the form of a sleeve, the bore of which is of larger diameter than the rod to enable 'said rod to slide freely therethrough.` The upper portionofthe sleeve is enlarged to rform a head, and this head is split by two diametrically-intersecting cuts 8 which thus divide it into foul" equal sectors 9 (Figs. 5 and 6) the confronting side walls of the sectors being formed yconjointly with tapering screwholes for the reception of tapered expanding screws 10'carryingnuts. 11 at their lower Y ends to `rhold them against displacement.

- i The peripheral'wall of the sleeve head is threaded for engagement with an internallyf threaded portionofthewallv of the case lo-v cated av suitable distance below the upper end thereof, so that it is thus possible toattach the sleeve to the case wall at any desired point within thefrange of the afore-y saidV threaded portion. The screws l0 can then be tightened to expand the head, whereupon the sleeve will be iirmly locked in place. So positionechfthe'impact rod 16 can movekfreely in opposite directions through p the sleeve, its downward movement being rlimited by the contact of nut l with the upper face of the sleeve. f

The portion of the bore ofthe sleeve which extends through the sleeve head, however, is y made slightly` smaller than'the boreof the sleeve proper (see Fig. 5), and this portion of the bore is enlarged, of course, when the expanding screws l0 are tightened, so that the rod can then pass freely through it. But when said screws are loosened, then the sectors 9 forming the 'head will ,tend to come together, thus contracting the aforesaid bore portion, with the result that the sleeve is firmly clampedto the rod. -Hence, inassembling the parts, the sleeve head is `rst expanded to enable it to heA fitted on the rod,

and then contracted to lock the twoparts together, after which the rod and sleeve are inserted into the case and the head jthereafter locked in adjusted engagement with -dinal series of stops the threaded portion of the case wall, thus releasing the rod from the sleeve head and leaving it -tree to move axially in either direction.

The working stroke of the redis e'iifected by means oi-an operating spring 13, here shown as coiled aroundthe central portion of the rod. One end of this spring bears upon an annular shoulder or collar 17 'formed upon or otherwise rigid-ly secured to the rod and provided with afbeveled edge,

while the other or upper end fits in a spiral groove 12 (Fig. 5) formed in the outer surface ot' the sleeve and is fastened in place therein by means of a. set-screw 14- and washer 15;the locking of said sleeve to the rod preventing the upper end of the spring from turning or twisting on the sleeve when the latter is being screwed into the threaded part of thee-ase.

As the sleeve is normally locked to the case, and as the spring 13 is of the-expansibletype, the tendency oi said spring` is to move the rod downward or outward. To provide the torce necessary for the working stroke of the rod, the spring' is cocked or compressed to an extent depending upon the character and thickness of the material to be tested. A preferred form of device for effecting this cooking or contracting action is shown in Fig. 3 and comprises a stemor bar 4provided along one side with a llongitu- 26, marked I to X, and of such a. size and shape that it vcan pass freely through the opening in the bottom wall 1910i? the case; An enlargement or base is provided on the lower endo'l this member, and its upper end has aseat or CII depression 25 formed therein to receive the terminal 1S of the impact rod, so that after the said

parts

18 and 25 have been engaged, the stem or bar can be forced inward through the aforesaid opening into the interior ot the case. thereby moving` the rod backward and contracting the spring until the desired stop 26 reaches the case opening. Oneway ot doing this, is to rest the device 'upon a suitable support by means of its base, thenv position the implement directly thereabove, with the

parts

18 and 25 engaged, and then pressv downwardly upon the caseunt-il the stem 'ot the device has moved in ard to the required extent.

Y'oretain the parts in cocked position, a detent lever2l is utilized which also serves to uncock or release them. rllhis lever is disposed longitudinally and exteriorly of the case.l and is tulcrumed intermediate its ends in a bracket on said case, asrepresented in Fig. 1. The lower arm ol" the lever is formed along its inneredge with a series ot ratchet teeth 2l, marked I to X tol agree with the marking` of the stops 2S; and immedi ateljv below the lowest tooth, which is marked l', there is a lateral projection or lug serving to indicate the normal position of the impact rod and marked 0. The portion of the case immediately opposite the toothed portion of the lever is formed with a longitudinal slot or opening, through which the said portion oi" the lever projects, due to the action of a spring 23 interposed between the case and the upper arm of the .lever and, hence` situated above the ulcruin oit the latter. Both the teeth 2l and the lim- 22 are designed to coact with the collar or shoulder 17 on the rod; and in the normal or zero position of the rod, which is illustrated in Fig. 1, the lug engages the under surface ot'said collar, and said ksurface is disposed almost, butnot quite, in contact with the upper face. of the partition 20. The teeth 21 slant upward, as shown, so as to oder no interference to the inward or upward movement or" the rod, the lever vibrating backward and forward -in its slot during such movement and engaging under the collar'l as the latter passes eachy tooth, sothat the .rod will thus be automatically locked against return movement. Inward movement oit the upper arm of the lever, however, will immedi ately release the lever 'from the rod collar, and the rod will thereuponl be instantly moved outward or downward by the expansion of the operating spring 13.

ln order to initially; balance the spring 13, one end of a beam (not shown) may be inserted through the hole 27 in the top of the case and hooked into the opening 3' in the upper end of the rod, and the required number ott Vweights are suspended from the other end ot the beam, whereupon the compression of the spring is measured. Y

The operation of the implement is bclieved to be apparent fromv theforegoing and, hence, to require no special explanation. It will be observed, however, that the operatlll ing spring is cocked without requiring-the e Yimplement to be pressed against the material to be tested, but that, instead, this action is eiected by means of the stem device illustrated in Fig.4 3. Consequently, it is possible vto adjust the tension lof the springend to set the impact rod with a great deal of nicety, as well as to position the flat end face 19 Aot the case squarely against the surface of thematerial.k This disposition oi' the aforesaid end face 19 places the axis of the rod truly perpendicular to the said surface, and the rod is accordinglyV compelled to strikev a direct blow thereagainst, all danger of a glancing or misdirected blow thusbeing avoided. Furthermore, it is to be noted that the operating' spring acts 'directly on the'impact rod, and thatthe latter-itselfstrikes directly against thc material, so that there is no waste eti'ort such as is necessarily present when the operating or impact element and the element which strikes the work are structurally separate Y bined locking and releasing lever LA not only performs the fuction speciied, but also serves to give noticefwhen, by reasonfol- Wear on or displacement ofany of they partsv within the case, a readjustment of the impact rod is necessary. v As has been explained, the rod' is .normally heldin z ero position, represented in Fig., l, invvhich the lug 22 on the lever catches under the collar or shoulder 17. This position it vassumes automatically immediately vfollowing its Working stroke, due ofcourse to thev recoiling of the operating spring after-its sudden expansion. If, now, fo'r'the reasons stated, such automatic engagement doesnot take place that fact is at once indicated and'` the need for further adjustment isapparent.

I claim as my invention 1. A resistance-testing implement, com` prising a ease havingone endadapted to be positioned directly against thefsurf'ace of the material being tested; an impact element-housed Within the case vand movable axially outward throughy said end to strike against said material; an operating spring 'for said element; and releasable means for holding said element in any selected one of a seriesof dil'erent, definite retracted positions in sai-d case with its operating spring cocked. f

2. A resistance-testing implement, com-- prising a case having one end adapted to be positioned directly against the surface ofV the material being. tested; an impact rod housed Within the case`and movable axially outward through said end to strike against said material; an operating spring' for the impact rod, said rod being movable inward of said case, against the action of saidl spring, to different predetermined eX- tents; and means, operable at will, for holding and subsequently releasing said rod in and from any selected retracted position.

3. A resistance-testing implement, according to claim l, in which the releasable holding means comprise a member having a set of ratchet teeth for selective engagement with the impact element.

4. A resistance-testing implement, according to claim 1, in which the releasable holding means comprise a member having a set of ratchet teeth for selective engagement With a shoulder on the impact element, the ratchet teeth and the edge of the shoulder heilig inclined or beveled in a ldirection toy enable the-free .inward movement of saidtain such engagement and k.to hold the other arm of the lever in releasing operation.

6. A resistance-testing implement, iconi-4 prising a tubular case having a` bottom end position to eff-ect the Wall Vprovided With a central opening; an

axially-movable impact element housed Within said case; an operating spring for moving said elementoutward through said opening to strike" against the material being tested; and releasalole meansfor 'retaining said element in retracted position in said case, said end Wall having a flat outer face which -is adapted to restsquarely against the surface 'ot'said material and to Which the axis of the impact element is perpendicular. f* s i 7. A resistance-testing implement, comprising a tubular case; an axially-movable impact element therein; ytixed and movable guides in saidv case through which said element passes, the movableV guide having means for releasably locking it to Lthe cas'c and tothe impact element; a spring-for efffecting the Working stroke of said' element; and releasable means for holding said element in retracted position with its operatings'pring cocked.`

, 8. A resistance-testing implement, `coniyprising a tubular case; an axially-movable `impact element therein; fixed and movable guides in said case through `which said element passes, the movablev guide having means for locking it alternatively to the case or to the impact element and simultaneously unlocking it from said element or from said case; a spring for electing thel Working stroke of said element; and releasable means for holding said element in retracted position with its operating spring cocked.

- 9. A resistance-testing implement, according to claim 7, in which the releasable locking means comprise a sleeve having ahead which is formedwitli a plurality of inter-` vil() ing a bottom end member formed with a central opening, an impact element movable, outward through said opening, an operating spring for said element, and relcasahle means for locking said element in retracted position; of a member engageable with the outer end of the impact element and adapted to be forced inward through said opening to retract said element and tension its oper-` ating spring. 11. The combination, with a resistancetesting implement comprising a. case hating a bottom end member formed with a central opening, an impact element movable outward through said opening, an operating spring for said element, and releasable means tor locking said element in retracted position; of a member engageable with the outer end of the impact element and adapted to he forced inward through said opening to retract said element and tension its operating spring, said member being provided along one side with a series of indicating deviceey which correspond to'dit'ferent predetermined tensions of said spring and which are adapted to coact with the edge ot said opening- Y 12. A resistance-testing in'iplenient, coinprising a case; an axially-movable impact element housed'therein; an operating spring forl said element; and` relcasable means for lockingksaid element selectively. in any one of a plurality of different definite positions, said locking means and impact element constituting companion parts, one of. which-is provided with a setrof ratchet teeth for intcrchangeable engagement with a projection on the other part.

13. A resistance-testing in'iplenient, coni. prising a case; an axially-movable impact element housed therein; an operating spring for said element; and a lever for releasably locking Said element in any selected one ot a plurality ot' different predetermined positions, 'said lever having a series ot ratchet teeth for interchangeable engagement with a projection on said element and aisoy having a lug at the foot of the series ot teeth to normally engage said projection.

14. The' combination, with a resistancetesting implement comprising a case having a bottoml endmember formed with a central opening, an impact element movable ont.- ward through said opening, an opeiatingspring for said element, and a lever having a set of ratchet teeth for interchangeable engagement with a projection on said element to releasably lock the latter in any selecte(l one of a plurality of kdifferent retracted positions; of a member engageable with the outer end of the impact element and adapted l to be forced inward through said openingl to retract said element, said n'ieinber being provided along one side with a longitudinal series of indicating devices for coaction with the edge of the opening, said devices cor responding with said ratchet teeth in number and spacing. Y

In testimony whereof I have hereunto set my name this ninth day of January 1923.

CARL EDVARD DAHLQVI ST.