US2999382A - Testing machine - Google Patents

Description

Sept. 12, 1961 J. c. MCCLELLAND TESTING MACHINE 3 Sheets-Sheet 1 Filed March 14, 1958 INVENTOR John c. Mccwumd ATTORNEY Sept. 12., 1961 J. C. M CLELLAND TESTING MACHINE 5 Sheets-Sheet 2 Filed March 14, 1958 FIGA INVENTOR John QMc Clelland w Wm ATTORNEY Sept. 12, 1961 J. c. MCCLELLAND TESTING MACHINE 3 Sheets-Sheet 3 Filed March 14, 1958 INVENTOR John C. M0 Uelland W .R. ilm

ATTORNEY United tates This invention relates to a testing machine, especially to crosshead positioning and holding means, and has for an object the provision of improvements in this art.

With many testing machines now used the shifting and locking of the crosshead is a very difiicult and tedious operation. In one form the crosshead is provided with rings which lock in spaced annular grooves formed in the columns. It is expensive to machine the grooves in the columns and the columns are greatly weakened at'the grooves. Besides, the spaced grooves provide only a limited number of positions where the crosshead can be secured to the columns.

One of the objects of the invention is to provide crosshead positioning means which do not require spaced grooves and the large solid columns required therefor but which permit securement at any point whatever along the columns; and since the columns are uncut they can be made of hollow tubes instead of solid bars, giving much greater strength and rigidity for the amount of metal used.

Another object is to provide means for rapidly moving the crosshead from one clamped position to another and for rapidly locking it in different clamped positions.

Another object is to provide means for locking the crosshead to the columns by fluid actuated clamping means which can be operated very rapidly.

Another object is to provide an improved grip for an annular fluid expansion bag such that the bag is not injured by the column gripping device which it operates; also in which the gripping device does not mat the column which it grips.

Another object is to provide an improved bag retaining means which will prevent the bag from being pinched or otherwise injured at corners or joints.

The above and other objects and novel features of the invention will be apparent from the following description of an exemplary embodiment, reference being made to the accompanying drawings, wherein:

FIG. 1 is a front elevation with parts in section, of a testing machine or press embodying the present invention;

FIG. 2 is a side elevation of the press;

FIG. 3 is a top plan view taken on the line 3-3 of FIG. 1; 1 I

FIG. 4 is a horizontalsection taken on the line 44 of FIG. 1; V i

FIG. 5 isan enlarged partial the line 5-5 of FIG; 4;

FIG. 6 is an enlarged vertical section of the column gripping arrangement;

FIG. 7 is a horizontal section and plan taken on the line 7-7 of FIG. 6;

FIG. 8 is a perspective view of a bag retainer; and

FIG. 9 is a section and plan like FIG. 7 but showing a modified gripping arrangement.

Referring to the drawings, the testing machine comprises a base 10 to which are secured vertical columns 11 secured together at the top by a tie member 12.

A lower crosshead or table 13 is slidably mounted on the columns for vertical movement and carries'a specim'en'grip 14 for engaging the lower end of a specimen S. upper crosshead 17 is also slidably mounted ori the columns, which "inthe upper par't "are. tubular, and is adapted'to belocked in position byfluid' operated column grippers 18. It raised and lowered when unlocked by vertical section taken on stem cables 19 attached thereto and actuated by a power device 20 mounted on the tie member 12. The power device includes a motor M and reduction gearing G which operate a drive shaft 21 carrying drive sprockets 22, 23 thereon for the sprocket chain cables 19. By passing the chain cables over the sprockets on opposite sides, passing them over idler sprockets 24, and connecting their other ends to a balance weight 25 in one of the hollow columns, the crosshead is properly operated by the driving mechanism. The cables pass over idlers 26, 27 in passing to the weight.

The specimen S is secured in the crosshead 1'7 by grippers 14 like those used on the table crosshead, a depending casing 30 being secured beneath the crosshead 17 to carry the grippers. Bolts 31 secure the casing 3th to a load cell assembly 32. It is not necessary to note this load cell in detail, that forming the subject matter of another application.

The table crosshead 13 is moved up and down by power means shown in FIG. 1. As there shown, the columns 11 are firmly secured to the base 10 as by nuts 34 and 35. Pistons 36 are rigidly secured on the columns 11. Cylinders 37 fit and operate on the pistons 36, the cylinders being secured beneath the table crosshead 13 by heads 38 and tie rods 39. The cylinders are tied together at the outer ends, thereby greatly bracing and rigidifying the table crosshead, as by a tie plate 40 secured by the rods 39. Fluid ducts 41, 42 are provided in the columns 11 for the supply and exhaust of fluid for operating the cylinders relative to the pistons, the ducts having side opening ports 43 and 44 which are partly closed at the cylinder heads at the ends or" the stroke to give a cushioning action. Tubes 45 and 46 provide for the supply and exhaust of fluid for the ducts 41 and 42.

The column gripping means are shown in FIGS. 6 to 8. As here shown the grippers 18 include an assembly which is disposed in an annular chamber 50 formed in the crosshead 17, the assembly being retained by an annular ring 51 secured over the open end of the annular chamber.

The gripper assembly includes clamping segments 52 disposed between the bottom of the annular chamber and the cover ring 51, each segment being faced with a friction lining pad 53. The segments are forced toward the column by a fluid bag 56 of annular shape fitting within the annular chamber 50, fluid being supplied and exhausted by way of a sealed flexible tube 57. Preferably hydraulic fluid is used and the pressure is very great, hence the protection against pinching is important.

The outer lower corner of the bag at the annular ring 5 1 is retained against pinching here by an annular angular ring 58 which embraces the corner of the bag.

In some cases of very high pressure it may be desir able to protect the inside of the bag further and, as shown, this is here accomplished by placing a thin flanged sleeve 60 within the bag. If the bag movement for clamp ing is very small this sleeve can be a continuous cylinder but for more movement it is slitted from opposite ends, as shown. The slitsare very narrow so that there is no danger of the bag being pinched, even if the sleeve is used alone with friction pads inside, as it may be; but when used over the segments 52, as shown in FIGS. 6 and 7, there is further assurance that the bag will not bepinched. The slits 61 of the sleeve are staggered relative to the spaces between segments, as shown especially 'in FIG. 7. In FIGS. 6, 7 and 8, for clarity of illus tration, the slits 61 are shown as having spaces'but actually the slit spaces are so narrow as to be invisible."

be used at the upper and lower inside corners where movement occurs to prevent pinching of the bag. The ends of the slits end at minute round holes to prevent cracking. The sleeve has suflicient resilience to force the bag outward when fluid pressure in the bag is relieved, making release of the column easier.

In the modification shown in FIG. 9 the spaces between segments 52, though normally practically invisible, are covered by strip shields 54 of extremely thin material to assure that the bag does not get pinched between segments. The strips may be attached on one side, as by adhesive, welding or other suitable method, depending on the kinds of materials used, to one of two adjacent segments, leaving the other side free to slide over the other segment.

In FIG. 9 the bag 56' is shown to be made with a gap on one side, as indicated at 56a, to allow bags to be inserted and removed around the columns 11 without requiring disassembly of parts from the columns as would be required to place or remove full ring bags from the ends of the columns.

It is thus seen that the invention'provides a simple convenient and effective means for quickly moving a crosshead to diflerent positions along columns and securely looking it in position, for bracing a crosshead table through its operating cylinders, for cushioning the movement of the table crosshead automatically if it moves the full length of the cylinder stroke, and for clamping the crosshead to the columns in a manner to assure that the fluid pressure bag will not be injured.

While certain embodiments of the invention have been described for purposes of illustratiomit is to be understood that there may be other embodiments and modi fications within the general scope of the invention.

What is claimed is:

1. A specimen testing machine, comprising in combination, a base, a plurality of columns carried by said base, a crosshead movable along said columns, power means for moving the crosshead along the columns, friction column grippers and power gripper operating means carried by the crosshead for looking it at any point along the columns, a table crosshead slidably mounted for axial movement along said columns, power means for moving said table crosshead along the columns, and means on each of said crossheads for engaging a specimen and stressing it endwise between them, said column grippers including longitudinally extending radially flexi: ble column clamping elements encircling the columns, means carried by said crosshead closely engaging the ends of said clamping elements and securely holding them against endwise axial movement on the crosshead, and said power means for operating the column grippers including means for forcing the intermediate portion between the ends of said clamping elements toward said columns completely around the circumference.

2. A testing machine as set forth in claim 1 wherein the power means for operating the table crosshead comprises a piston-cylinder device on each column, each cylinder-piston device including a piston on one of said columns and fluid ducts in the column having side-opening apertures on each side of the piston, the cylinder having heads with bores for the column arranged to cover said side-opening apertures at the ends of the range of movement to cushion the ends of the movement between piston and cylinder.

3. A testing machine as set forth in claim 1, wherein said grippers comprise axially rigid column gripping elements and an annular fluid pressure bag surrounding said gripping elements, the bag and elements being 4 the circumference, and slit cover sheets secured at one edge of the slit and slidable over the other edge of the slit to protect said bag against pinching at said slits.

5. A testing machine as set forth in claim 3, wherein said gripping elements form an annular sleeve surround ing said column for gripping it.

. 6. A testing machine including in combination, a column, a crosshead movable along said column, a second crosshead secured to the column, means on said crossheads to secure a test specimen between them, and gripping means carried by said movable crosshead for gripping the column, said gripping means including. an annular resilient sleeve completely surrounding theco'lumn and an annular fluid pressure bag surrounding the sleeve for forcing it toward the column for gripping the column, said sleeve being axially rigid and having means on said crosshead for holding its ends against axial movement and being radially flexible intermediate its ends for the gripping and release action.

i 7. A testing machine as set forth in claim 6, wherein said sleeve has flanges at the ends which partially em brace the ends of the bag.

8. A testing machine as set forth in claim 6, wherein said sleeve is slitted from opposite ends for part of its length in alternate circumferential locations.

. 9. A testing machine asset forth in claim 6, wherein said annular bag is divided at one point along an axial line and has closed ends at said point of division so asto be insertable and removable laterally of the column.

10. A specimen testing machine, comprising in combination, a base, a plurality of columns carried by said base, a crosshead movable along said columns, power means for moving the crosshead along the columns, fricconfined against axial movement and acting radially on said elements to grip the column.

4. A testing machine as set forth in claim 3, wherein said gripping elements are formed with axial .slits around tion column grippers and power gripper operatin'gmeans carried by the crosshead for kicking it at any point'along the columns, a table crosshead slidahly mounted for axial movement along said columns, and means on each of said crossheads for engaging a specimen and stressing it endwise between them, the. power'mea'ns for operating said table crosshead including piston-cylinder devices on the columns, the cylinders at one end being secured to the table crosshead, and a tie member secured to and connecting the other end of the cylinders to resist transverse movement when loads are applied whereby to rigidify the assembly of table crosshead and cylinders.

11. A specimen testing machine comprising, in combination with a column and a crosshead movable along the column for securement thereto in any adjusted position along its length, fluid-actuated gripping means carried by said crosshead for gripping the column, saidgripping means including enclosure walls on said crosshead form-, ing an annular fluid chamber around said eolumn means for supplying pressure fluid to said annular chamber and discharging it therefrom, and a fluid-tight circumferen tial wall'closing said annular chamber on the inner side, said wall including an axially rigid transversely flexible full 1 circumferential sleeve, and transverse abutment means on said crosshead closely fitting the ends of said sleeye to hold it against axial movement whenthe column is gripped. 7

12. .A specimen testing machine as set forth in claim 11, wherein said fluid-tight circumferential wall comprises, in addition to said sleeve, flexible elastic sealingmeans forming with said sleeve a full fluid tight column enclosure on the inner side of said annular chamber.

References Cited in meals or this patent UNITED STATES PATENTS- 2,778,865, Kon'gsgaarden'

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