US1745634A - Machine for testing the bending strength of metal strips - Google Patents

Description

FeB.-4, 1930.

J. H. NEAD ET AL MACHINE FOR TESTING THE BENDING STRENGTH OF METAL STRIPS Filed Aug. 25, 1927 2 Sheets-Sheet A TTORNE Y.

Feb. 4, 1930. J. H. NEAD ET AL MACHINE FOR TESTING THE BENDING STRENGTH OF METAL STRIPS Filed Aug. 25, 1927 2 Sheets-Sheet My 34 INVENTOR A TTORNE Y.

Patented Feb. 4, 1930 UNITED STATES PATENT OFFICE JOHN H. NEAD, REID L'KENYON, AND CLARENCE W. RUST, OF MIDDLETOWN, OHIO, ASSIGNORS TO THE AMERICAN ROLLING MILL COMPANY, OF MIDDLETOWN, OHIO,

A CORPORATION OF OHIO MACHINE FOR TESTING THE BENDING STRENGTH OF METAL STRIPS Application filed August 25, 1927. Serial No. 215,466.'

- Our invention relates to machines for testing the bending strength of metal strips, and particularly to a motor driven machine for this purpose,

Broadly, it is our object to mount a scale beam so that the bending strength of a piece of metal or other material to be bent, may be registered in terms of units of load required. A simple type of machine for this purpose may be made by mounting a scale so that the beam of the scale will be attached to a bending bar. The piece to be bent and tested may be held in a fixedly mounted member above the bending bar, and the scale moved away from the mounting member, or vice versa, with the result that the force which is required by the bending bar to bend the sample is registered on the scale.

It is a specific object of our invention to provide improvements which will tend to avoid inaccuracies in such types of machines. In our preferred form it is our object further to provide a machine which may be operated by a constant source of power such as will be provided by an electric motor. The above and other objects to which reference will be made during the ensuing disclosure we accomplish by that certain arrangement and combination of parts of which we have shown a preferred embodiment.

In the drawings Figure 1 is a side elevation of our improved testing machine.

Figure 2 is a perspective view of the machine shown in Figure 1.

Figure 3 is an end elevation of the machine.

Generally indicated at 1 we. have shown the frame of the machine. Within a channeled portion 2 there is mounted a carriage 3 having sample supporting portions 4, and with overhanging ledges 5 which retain the ends of the strip of metal to be tested. The carriage is pivotally supported by a link 6, and a counter-weight 7, secured to a cable 7 passes around the pulleys 8 and is attached to the end of the link 6 so as to counterbalance the weight of the carriage. The link 6 has rack teeth 9 which are engaged by a pinion 10 which is rotated through a chain of gears 11, 11, operatively connected with an electric mo- I pinion 10.

tor 12. It will be' observed that the link 6 may be inclined to the left to disengage the pinion. A pivoted handle 13 journaled in the machine frame at 14 has a roller 15 which, when it is desired to move the rack into engagement with the driving pinion, is depressed, thereby tilting the link to the right. \Vhen it is desired to release the engagement of the rack with the pinion, the operator releases the handle and the counterweight may be caused to rock the link to the left, in which position it is disengaged. In order to make the releasing action more positive, we also preferably attach a spring 16 to the frame 1, and we attach the other end of the spring to the link. This arrangement, which is illustrated in Figure 1, normally pulls the link to the left so that it requires some slight downward pressure on the handle 13 to bring about the engagement of the rack 9 and the The tool or bending bar which we prefer to use to bend the metal strip which we have indicated in dotted lines at 16, has a strip engaging upper face 17 and a body 18 which is slidably mounted in a substantially vertical walled aperture 19 in the supporting plate 4. The lower end of the body 18 has a bearing 20 which is carried by an arm 21 of a pivoted lever. Intermediate the ends of the lever we have shown a bearing 23. The lever having 7 the portions 21, 22, has a fulcrum bearing 24 which is adjustable by means of an adjusting screw 25. The bearing 23 is mounted in a cross member 26 extending between suspended links 27. The links are carried by a bearing 28 located intermediate the fulcrum bearing 29 of another lever and the arm thereof.

This upper lever has at the end opposite the fulcrum a bearing 30 which is so disposed as to bear against a hooked frame 31 which engages the balance arm or beam 32 of a scale generally indicated at 33.

For enabling accurate setting of the several parts of the balancing mechanism eonnccted with the scale, we have shown the adjustable support 36 which controls the height of the scale, and the adjustable carriage 34 which controls the position of the fulcrum bearing 29.

The adjusting screws 25 and 35 are used to secure the proper alignment of the lower beam 21, 23. When the knife edge 24 is bearing on the lower end of 25 as a fulcrum point the lever ratio of the beam system is such that the load applied at the point of contact with the sample at 17 is equal to the load transmitted to the scale beam at 32. By raising the fulcrum 35 until in contact with the knife edge 37 and backing off the fulcrum 25 until free from the knife edge 24, the flever ratio may be changed so that the load transmitted to the scale beam at 32 is some fraction of the load applied at the point of contact with the sample at 17. In the particular case illustrated this is one tenth although this value may be made different in order to per.- mit operation of the machine over other ranges of loads.

When the lever ratio is changed from one to-one to one-to-ten or to some other ratio as indicated above it will be necessary to change the zero adjustment of the scale on account of the change in the dead load of the leyer system on the scale beam 32 brought about by a change in fulcrum points.

The operation of testing a piece of metal will now be described. The piece of metal cut to size and of a known gauge is inserted on the supporting parts 4 as indicated at 16. The motor is then turned on and the pinion 10 begins to rotate. The handle 13 is then depressed and the rack beginsto force down -the carriage 3. The piece of metal being held between the overhanging ledges 5 will be moved down into engagement with the face 17 of the member 18. The member 18 will at first bear downwardly against the arm 21 of the lower lever and through the connec tion with the upper lever the scale will begin to progressively indicate the increased downward pressure in the terms to which the indicia are graduated.- As the carriage 3 is forced downward the sample bends more and more and as it does so the load increases until a certain point, which is characteristic of the material, at which there is little or no increase in the load, although the bending continues at a uniform rate, This is a definite point and is characteristic for a given material and is taken as the end point of the test.

The motor is preferably geared so that the movement of the carriage downwardly will be gradual, so that it will be simple for the person testing the metal strip to establish his end point which is, as will be readily understood, that point at which there is nofurther progressive increase in the scale 'reading.

Having thus described our invention, what we claim as new and desire to secure by Leted. a member adapted to bear against a sample intermediate the ends thereof while said sample is disposed on said carrier, said member guided by said carrier. and movable relatively thereto, a scale having a balance beam operatively connected with said member, and means for moving said carrier, whereby said member is thrust against said sample to be tested, and the force required to bend said sample registered on said scale.

2. A machine for testing bending strength, comprising a carrier for a sample to be tested, a member adapted to bear against a sample intermediate the ends thereof while said sample is disposed on said carrier, said member guided by said carrier and movable relatively thereto, a scale having a balance beam operatively connected wlth said member, and means for moving said carrier, whereby said member is thrust against said sample to be tested, and the force required to bend said sample registered on said scale, and means for retaining said sample on said carrier.

3. A machine for testing bending strength, comprising a carrier for a sample to be tested, said carrier having an opening therein, a member adapted to bear against a sample intermediate the ends thereof while said sample is disposed on said carrier, said member havingrelative movement with relation to said carrier, a scale havin a balance beam operatively connected with said member, and means for moving said carrier, whereby said member is thrust against said sample to be tested, and the force required to bend said sample registered on said scale and means for retaining said sample on said carrier, and said member slidable throughsaid opening in said carrier.

4. A machine for testing bending strength, comprising av carrier for a sample to be tested, a member adapted to bear against a sample intermediate the ends thereof while said sample is disposed on said carrier, said member having relative movement with relation to said carrier, a scale having a balance beam operatively connected with said member, and means for moving said carrier, whereby said member is thrust against said sample to be tested, and the force required to bend said sample registered on said scale, said means for moving said carrier comprising a motor and a chain of gears with a rack operatively connected with said carrier which one of said chain of gears is adapted to engage, and manually operative means for inhibiting the engagement of said gear and rack.

intermediate the ends of said strip in a direc tion away from said carrier portion against a metallic strip disposed on said carrier porbend said metallic strip.

6. A bend testing machine having a carrier on which a metallic strip to be tested may be disposed, a bending bar having relative movement with relation to said carrier adapted to bear against a metallic strip disposed on said carrier intermediate the ends of said strip, means for inducing relative movement between said carrier and-said bending bar, and means for indicating the pressurerequirjed by said bending bar to bend said metallic strip, said means-for inducing relative movement comprising means actuative by a constant force with means for inhibiting the application of said force to said means.

7. A bend testing machine having a carrier on which a metallic strip to be tested may be disposed, a bending bar having relative v n. movement with relation to said carrier adapted to bear against a metallic strip disposed on said carrier intermediate the ends of said strip, means for inducing relative movement between said carrier and said bending bar, and means for indicating the pressure required by said bending bar to bend said metallic strip, said means for indicating pres-.

sure comprising a scale with a series of levers operatively connected with said bending bar, and means for shifting the fulcrum of at least one of said levers.

8. A bend testing machine having a carrier on which a metallic strip to be tested may be disposed, a bending bar having relative movement with relation to said carrier adapted to bear against a metallic strip disposed on said carrier intermediate the ends of said strip, means for inducing relative movement between said carrier and said bending bar, and means for indicating the pressure required by said bending bar to bend said metallic strip, and means for counterbalancing the weight of said carrier.

9. A bend testing machine having a. counterbalanced carrier on which a metallic strip to be tested may be disposed, a bending bar having relative movement with relation to said carrier adapted to bear against a metallic strip disposed on said carrier intermediate the ends of said strip, a scale having a balance beam connected through a series of balance levers, one lever being fulcrumed to said bending bar, and mechanical means for inducing relative movement of said carrier and bending ba'r, whereby the force required to bend said strip may be indicated.

10. A bend testing machine havin a coun terbalanced carrier on which a meta lic strip to be tested may be disposed, a bending bar having relative movement with relation to said carrier adapted to bear against a metallic strip disposed on said carrier intermediate the ends of said strip, a scale having a balance beam connected through a series of balance levers, one lever being fulcrumed to said bending bar, and mechanical means for inducing relative movement of said carrier and bending bar, whereby the force required to bend said strip may be indicated, said means to induce relative movement of said bending .bar and carrier comprising an electric motor with inhibitive mechanical means connecting said motor'and carrier.

11. A bend testing machine having a counterbalanced carrier-on which a metallic strip to be tested may be disposed, a bending bar having relative, movement with relation to said carrier adapted to bear against a metallic strip disposed on said carrier intermediate the ends of said strip, a scale having a balance. beam connected through a series of balance levers, one lever being fulcrumed to said bendingbar, and mechanical means for inducing relative movement of said carrier and bending bar, whereby the force required to bend said strip may be indicated, said levers being so arranged with relation, one to another, that one lever is suspended. from the other, the suspending lever being connected with the beam of ascale, and the suspended lever being connected with said bending bar.

12. A bend testing machine having a counterbalanced carrier on which a metallic strip to be tested may be disposed, a bending bar having relative movement with relation to said carrier adapted to bear against a metallic strip disposed on said carrier intermediate the ends of said strip, a scale having a balance beam connected through a series of balance levers, one lever being fulcrum'ed to said bending bar, and mechanical means for inducing relative movement ofsaid carrier and bending bar, whereby the force required to bend said strip may be indicated, said levers being so arranged with relation, one to another, that one lever is suspended from the other, the suspending lever being connected with the beam of a scale, and the suspended lever being connected with said bending bar, and means for adjusting the positions of the fulcrums of said levers.

13. A bend testing machine having a supporting frame, a carrier slidably mounted with relation to said frame, means for counterbalancing the weight of said carrier, said carrier having means for retaining thereon a metallic strip to be tested, a bendlng bar extending loosely through said carrier, said bar operatively connected with an indicating scale, and motor actuative means for moving said carrier so that a strip retained thereon will be carried into engagement with said bending bar, and the load required to bend the piece registered on said indicating scale.

14. A machine for testing the bending strength of a piece of metal cemprising a member for engaging said metal piece inter mediate its ends, and a member having means to engage the ends of the material outside of said first mentioned member, and a means for moving one of said members by a steady force toward the other, and a pressure indieating device connected to said other member so as to continuously indicate the pressure imparted to said other member, this connection being made through a system of beams and levers with adjustable fulcrum points arranged so as to permit employment of different lever ratios for transmitting the pressure from said other member to the pressure indicating device, whereby when the pressure indications cease to rise, an indication Wild be given which provides the factor for which the test is made.

JQHN H. NEAD.

REID L. KENYON.

CLARENCE V7. RUST.

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