US2577944A - Machine for testing tensile, compressive, bending, shearing, etc., strength of metals or other materials - Google Patents

Description

mm 121 E9521 Fil ed Sept. 13, 1946 ARTHU S A. R. MACHINE FOR TESTING TENSILE, COMPRESSIVE,

BENDING, SHEARING, ETC. STRENGTH OF METALS OR OTHER MATERIALS 3 Sheets-Sheet l Dneco i1 ARTHUEg MACHINE FOR TESTING TENSILE, COMPRESSIVE,

BENDING, SHEARXNG, ETC. STRENGTH OF METALS OR OTHER MATERIALS Filed Sept. 15, 1946 5 Slwe'is Slwet 2 INVENTOR:

Albert Rene Arf/wis DCD ll 1, 1951 A. R. ARTHUIS 2,5?Z944 MACHINE FOR TESTING TENSILE, COMPRESSIVE, SENDING, SHEARING, ETC., STRENGTH OF METALS OR OTHER MATERIALS 3 Sheets-Sheet 3 Filed Sept. 15, 1946 'INV-ENTOIZ: A/beri Rena Ari/1M5 Patented Dec. 11, 1951 MACHINE "FOR TESTING TENSILE; COM- PRESSIV'E," BENDING, SHEARING, ETC., STRENGTH'DF METALS OR OTHER MATEA.

RIALS '5 Albert Rene.Arthuis,,Paris;vFrance.

Application september 13, 1946;Serial No. 696;676 In France June 26, 31946 c 1 Claim. (01. 73-93 The presentinvention relates to a machine for testingzrtensile; compressive, bending, shearing, etc. strength of metals orothermaterials,:without. any other modification on said machine-than the change of the atools which are intended-to actup'on the test samples.

This machine is characterized byltheyfact that a dynamometricepparatus is hydraulicallyccupled with a press in order to allowthe reading of "the stresses being made' upon a dial: and, at the same timey: to :obtain 'thediagrams offthe stresses and ofthedistortions to which the test samples'are subjected Theitwo pistons in questidn; one of the press, the other ofxthe. dyna mometric apparatus or inferential piston; take up simultaneouslythe isame zipressure supplied by a pump.

The dynamometricapparatus-.isi'fnitther characterized by the fact that-it: enables'th'e modificati'on of the sensitivene'ss ofrthe. machine by means of suppression-"or adjunction of 'One.-:o1' a'p1-iira1'' ity of springswhich are controlledbyathe differ ential piston," and by the adjustmentofiian. abut ment which 'retainszysaid springs;

Another feature: of the invention/enables; the machine to-extend its scope of action; by adding to cth'esm'achine a wholearange oir sensibilities which 'are achieved no longer through .ithe single modification '01 the st'rengthiof ithe dynamom eter springsibut' conjointly through -a' modifica s tion' of the active area of the press piston:

In "orde'n to attain that-purpose the. invention uses"a plurality of telescopical pistons, that of. the greatest size bearing or constituting the cylin der of that of the immediate smaller area,"which latter-"containsthe following piston, and so on. With this arrangement, it becomes possible to let act the mainpiston' whieh provides the greatest stress or'to make-thelatter immovable, which becomes then the cylinder of the'piston of'lesser area, or further to make the two prior immov able, whilst a third pistonacts' alone and so on.

The stresses being a direct function of th'e cross-sections; if for instance 'the variouspistons are-at the ratio the-maximumstr'ess which may be exerted by each piston of the series will benete. of'the stress which the main piston is able toexert:

With that device; the same relative accuracy is preserved," since'the'dynamometer is-still afi I fected by' the-pressure given by-the pump; for that reason, its-springs; regardless 'of the piston used, will always-require thesame pressurein order to attain their same maximum compres sion.

The number of thesensibilities:becomes there" fore equal to the number ofcombinationswhich,

- ing uponthesamples being-tested.v

Of coursethe dial of the dynamometer is, provided with graduated scales equal innumber-to that of possible combinations, the. maximum amplitude of the needle-giving in any -case the maximum stress. of the combination which has been chosen.

Fig.1 1 is anv elevation with a partial cross-sece. tionof the machine as mountedlfor axtension test:

Fig. 2- shows the fitting for a compression rtest with the aid of. a ball.

Fig. S'is an enlarged view witha half -cross;- section and half elevation of the. dynamometric apparatus.

Fig. 4 is a partialside -view of:Fig.-,3.

Fig. 5 shows an enlarged vertical cross section of the arrangement of 'the -telescopical pistons: which permits to obtain-six :diiferent' sensibilities :in conjunction with the :dynamometric pde VlCe."

The machine comprises a press 'I with :its -piston 2 which is adjusted withoutzany intermediate. tightening member in a cylinder- 3 forming also a-'contalner.

To that press isxisecured'by meansiof' adug 4 the: dynamometrie apparatuswhich comprisesasecond unit such as a piston 5 :and a cylinder '6 of a lesser size and connected to the cylinder :3

by=a conduit 1.

A screw ll passesthrough a head =12 set above thepiston -2 and the vertical motion is'perfo'rmed without-rotation by means of the wheel i3 acting as a nut;

A pump Sacts at th'e same timeupon thelower faces ofbistons-Z and "5. The piston 2 acts upon the test sample secured between the cla'mps' 9 "andl0,andthe-other-piston 5 actsuponone or-a plurality ofspringsR and R ofthe dynamometric apparatus.

The dynamometric apparatus is provided both with-a dial "for reading and a recording device.

The stresses are read upon" the dial i4 over which moves a needle which is controlledby'a roller- 29 connected to the differential"piston- 5- bythe medium-of a cable-C.

The recording-deviceiis of the drum type." The: device It? *is controlled" by the vertical motion ofthe piston? and 'is' connected therewith by the medium of a support l6 carried by the piston 2, a roller l1 and a cable I8 extended between drum I5 is either secured to a spring or is stretched by a weight 24.

The dynarnometric apparatus is completed by a device allowing the modification of the sensitiveness of the stresses. It comprises a hollow sleeve 25 movable within a head 26 which both serve as abutment-s for springs R, R, the sleeve being able to be stopped by a locking device 21.

A spring 23 is intended to maintain the sleeve 25 I in its upper position when it is not locked.

The operation is as follows: the test samples E being suitably shaped for the test to be performed are clamped at the same time by a clamp 9 secured to the main piston 2 and by a clamp l9 secured to the screw I i, said screw serving to vary the distance between the clamps in accordance with the size of the samples to be tested.

' The pump 8 being set in movement an increasing pressure is exerted in the two cylinders 3 and 6. The piston 2 being pushed in vertical direction (assuming that a tensile test is to be performed), the upper clamp 9 which is made integral with said piston tends to go away from the clamp l9 and exerts therefore upon the sample a tensile stress which increases up to breaking of the same.

The differential piston 5 is simultaneously also subjected to a vertical pressure and compresses the spring R, or the two springs R and R, the purpose being to give the piston a stroke which is at a direct ratio with the pressure exerted within the two cylinders-and therefore with the stress to which the test sample is subjected. This stress may thus be indicated upon the dial M by an'e'edle which amplifies the stroke of piston 5, since it is coupled with the latter by means of cable C passing around the roller 29 which is secured to the axis of the needle.

When the two springs R, R are in operation, the maximum course of piston 5 is only attained for the maximum power of the machine but the spring B may be made free by raising the sleeve 25 to a height slightly above the maximum stroke of the piston.

This stroke corresponds then only to a fraction of the maximum power of the machine, which gives the latter a greater sensitiveness. A combination of three or four springs, instead of two, may provide a greater number of sensibilities by letting it in operation separately or in groups. Upon the dial is a number of graduations corresponding to that of the various sensibilities. Accordingly to theFig. 5, the sensibilities may be increased by the modification of the press piston. In this arrangement 3 is the main cylinder enclosing its piston 2 which is provided inwardly with a cylinder 30 formed integral therewith wherein slides a piston 3| the hollowed and bored center of which constitutes the cylinder for a piston 32. The lower part of cylinder 30 is provided with a central channel 34 which discharges into the lower part of piston 2 and sets constantly incommunication the cylinders 3, 30 and 31.

. The upper flange of piston 2 afiords two holes 4 35 which enables the latter to be made integral with the body of the machine by means of two screw threaded studs 36.

The piston 3| may further be made integral with its cylinder 30 by the medium of two grub scre'ws3'l overlapping-the junction of the two parts or otherwise.

Conduits and gutters 38 and 39 are provided at difierent places for discharging the oil which ensures automatically the lubrication. Finally, the upper part of piston 32 afiords a cavity 40 which receives the centering disc of difierent apparatus.

The operation is the following:

1. In order to achieve great stresses the piston 2 is made free of the machine body by unscrewing the nuts of the studs 36-in the position of the drawings-and the assembly operates at the same manner as when the piston 2 would not contain any inner member.

2. In order to obtain mean stresses, the piston 2 is made unmovable and the grub screws 31 are removed. In that case the pressure acts only upon hte section of piston 3|. I

3. In order to perform the smallest stresses the piston 2 is made unmovable as is also the piston 3|. In that case, the pressure acts only upon the section of piston 32 The diagrams are obtained by the horizontal motion of the paper wound around the drum l5 which is driven by the movement of the piston used, in correspondence with the elongations or distortions of the test samples, and by the vertical displacement upon the same paper of the marking device H) which is raised through the medium of the double stepped pulley 22, which has the purpose of amplifying the motion of the diflerential piston 5.

- Having thus described my invention I claim:

A machine for testing the strength and distortion of test samples of metals and other materials, having a hydraulic main press having a cylinder, and a stress-exerting piston of variable active cross-section, said machine comprising, in combination, a dynamometric apparatus constituting an hydraulic press and having a cylinder and a piston, means connecting the last-mentioned cylinder to the cylinder of the main press, adjustable springs, means connected with said springs for balancing the common pressure upon the piston of said dynamometric apparatus and the piston of the main press, a dial and a needle cooperating therewith for showing the stresses of the test samples, and a recording apparatus for recording the same in response to the motion of either piston.

ALBERT RENE ARTI-IUIS.

REFERENCES CITED The following referencesare of record in the 2,295,249 Yates Sept. 8, 1942

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