US2554206A - Automatic hardness tester - Google Patents

Description

y 1951 r F. PEARSON ET AL 2,554,206

AUTOMATIC HARDNESS TESTER Filed Feb. 4, 1950 AMPL IF AMPLIFIER AMPLIFIER Inventor: Fribh'lof L earson, A|T r on BSpawdin b, by [Q M His Attorney Patented May 22, 1951 AUTOMATIC HARDNESS TESTER Frithiof L. Pearson,

Our invention relates to improvements in hard ness testing machines for efiecting the automatic operation of one variety thereof.

To obtain the hardness number of a test specimen on one form of hardness testing machine as presently constructed, the specimen is placed upon the platform of the machine. The machine is manually operated to raise the specimen to the penetrator or brale and continued to be operated to zero two indicator needles pivoted upon a dial of the machine. A handwheel is then operated to set the dial to zero.

Another manual operation of the machine applies the major load to the specimen. When the hardness number is indicated by one of the indicator needles, the platform is lowered and the specimen is removed.

The object of our invention is to provide apparatus to make a hardness testing machine automatic so that the operator need only place the specimen upon the platform and remove it after the hardness is recorded by the needle.

According to our invention, a motor is provided to drive the platform of the testing machine. When a specimen is placed upon the platform, an electric eye switch starts the motor, which continues to run as the specimen contacts the brale and until the dials are simultaneously zeroed. The motor is stopped by electric eye switches acting in combination with a solenoid switch having a pair of contacts, one of which breaks the contact to the drive motor. The other contact energizes a solenoid brake on the motor and operates a switch energizing a motor to apply the major load to the workpiece. i

A pair of snap switches operated by the platform and by a lever controlled by the load motor energize a solenoid control operating a reversing switch of the drive motor. controlled by application of the major load by the load motor to de-energize the drive motor while the major load is being applied.

The platform is provided with limit switches to disconnect the drive motor in case of overdrive of the platform while a solenoid operated spring centered switch controlled by push buttons energizes the drive motor for opposite drive when either limit switch is opened.

Reference is made to the accompanying drawing, the single figure of which is a schematic view of an embodiment of our invention.

According to the drawing, switch connects leads 2 to a source of electric power 3. When switch is closed, the specimen 4 is placed upon a platform and interrupts a beam of light be- Another switch is Saugus, and Almon E. Spaulding, Lynn, Mass., assignors to General Electric Company, a corporation of New York Application February 4, 1950, Serial No. 142,495

3 Claims. (01. 73-83) tween light source 6 and a photoelectric cell 1. The signal from cell 1 passes through amplifier 8 to complete the circuit from leads 2 to close solenoid switch 9 completing a circuit from leads 2 through switch It, contacts ll of switch I2, limit switches I3 and 4 and contacts l5 of reversing switch It through motor I! to leads 2 thereby operating motor H. A worm l8 mounted upon the shaft of motor meshes with a gear i9 rotating upon frame 20 of the machine and provided with an axial bore threaded to raise or lower screw 2| upon which platform '5 is mounted. When contacts I5 of switch l6 are closed, motor I! operates in the direction to raise workpiece 4 to meet penetrator or brale 22.

As platform 5 is raised, an extension 23 of platform 5 operates a snap switch 24 to open the connection between a source of power 25 and 26 and de-energize solenoid 21 allowing it to be withdrawn by spring 28. Motor continues to raise platform 4 to engage brale 22 to impose a minor load upon specimen 4. The machine is provided with an indicator dial 29 upon which are pivotally mounted two indicator needles 30 and 3| connected by a lever system to brale 22.

Motor l1 drives platform 5 upward until indicators 3B and 3| simultaneously arrive at zero position indicating that the minor load is bearing upon workpiece 4. Slits are provided in dial 29 behind the zero positions'of the needles 3!] and 3|, and light sources 32 are focused through the slits upon photoelectric cells 33. These cells are connected to amplifiers 34 and 35, the outputs of which are connected in series in a circuit between a solenoid 36 operating switch l2 and leads 2 so that when the light beams from source 32 are interrupted by needles 3!! and 3|, simultaneously the circuit is closed energizing solenoid 36 to operate switch l2. As switch 12 is operated, contacts 31 are closed to energize a circuit between power source 25 and 26, energizing solenoid switch 38 to operate motor 39. Motor 39 is belt connected to a shaft 40 upon which is mounted a cam 4|. In the position shown, cam follower 42 of cam 4| supports a lever 43 pivoted at one end upon frame 20 and from the opposite end of which a weight 44 is suspended. As motor 39 rotates cam 4|, lever 43 lowers allowing the major load to be applied to specimen 4 through lever 43 and a member 45 bearing upon brale 22.

A cam 46 is also mounted upon shaft 40 operating a follower arm 41 and designed to raise arm 41, during the time the major load is applied, to operate switch l0 interrupting the circuit between leads 2 and motor l1. As arm 41 rises, it

operates a snap switch 48 to complete a circuit between source 25, 26 through solenoid 49 actuating solenoid 49 to close contacts 50 of switch l6 reversing the polarity of motor I! in readiness for the return of platform to its original position.

When contacts 31 of switch l2 are closed, a circuit is completed between source and 26 through solenoid 5| operating motor brake 52 to stop motor ll. During a single revolution of cam 4|, follower 42 is lowered from the position shown to allow the major load to be aplied to workpiece 4 and is returned to the original position. During this time, indicator needle 3| records the hardness number of the specimen upon dial 29.

When indicator needle 3| leaves the zero position to indicate the hardness number, connection to solenoid 36 from line 2 is interrupted. A circuit is provided energized by switch 53 operated by arm 41 to hold solenoid 36 energized while the major load is applied to specimen 4. There is no discontinuity between the time solenoid 36 is energized through amplifiers and 34 and through switch 53 since there is a time lag between the starting of motor 39 and the movement from zero of needles 30 and 3| due to cam 4!.

When the major load is removed by cam 4|, arm 41 drops to open switch 53 and de-energizes solenoid 36. With solenoid 3B de-energized, switch l2 operates closing contacts II in the circuit of motor I! and opening contact 3'! releasing brake 52 and disconnecting load motor 39. When follower 42 returns to its original position removing the major load from specimen 4, arm 41 drops back allowing contact to be made in switch Ill completing the circuit to motor I! which operates to drive platform 5 down to its original position.

As platform 5 descends, projection 23 operates switch 24 to close contact between source 25, 26 through solenoid 21 to energize solenoid 21 causing it to actuate snap switch 48 opening the circuit between source 25, 26 through solenoid 49, de-energizing solenoid 49 to allow switch [6 to close contacts [5 again reversing the polarity of motor I! to prepare it again to move table 5 upward. A projection 54 upon platform 5 operates limit switches l3 or l4 to disconnect motor I! if for any reason motor I! continues to drive platform 5 beyond the desired upward or downward travel. A spring centered switch 55 connects the leads of motor I! to leads 2 and is operated bypush buttons 56 and 51 operating solenoids 58 and 59, respectively, to reverse motor I! if it should be disconnected by limit switches 13 and I4.

While certain specific embodiments have been shown and described, it will, of course, be understood that various modifications may be made without departing from the invention. The appended claims are, therefore, intended to cover any such modifications within the true spirit and scope of the invention.

What we claim as new and desire to secureby Letters Patent of the United States is:

1. In combination, a hardness testing machine including a platform to support a test specimen, means for elevating and lowering said platform, a penetrator device for applying load to said specimen, means for loading said penetrator device and a device for indicating penetration of said specimen, said indicating device including adial and-an indicator-needle pivoted upon said dial, and control means comprising motor means driving said elevating means connected to a source of electric power, photoelectric switch means responsive to the presence of a specimen upon said platform to energize said drive motor, an electromagnetically operated multiple switch means responsive to the positions of said needle to energize and de-energize the electromagnet of said multiple switch, an electromagnetic brake mounted upon said motor, means controlling said loading means, contacts mounted upon said multiple switch to energize said controlling means and said brake in response to arrival of said needle at zero position, electromagnetic reversing means controlling said drive motor, control means connected .to said reversing means responsive to operation of said loading means to energize said reversing means and responsive to a limiting movement of said platform to de-energize said reversing means, limit switches controlling said drive motor responsive to travel of said platform to disconnect said drive motor at the ends of travel of said platform, separate reversing means controlling said drive motor and manual switch means controlling said reversing means to reverse the direction of travel of said motor when deenergized by said limit switches.

2. In combination, a hardness testing machine having a platform to support a test specimen, means for elevating and lowering said platform, a penetrator device for applying a load to said specimen, means for loading said penetrator device, means for indicating the amount of penetration of said penetrator into said specimen including a dial and a pair of indicator needles pivoted upon said dial, said dial having a pair of slits therein positioned at the zero position of said needles, control means for said machine comprising motor means for operating said elevating and lowering means, means for controlling said motor means including a photoelectric switch, said photoelectric switch being energized when a test specimen is placed on said platform, a solenoid operated multiple switch having pairs of contacts, switching means controlling said multiple switch according to the position of said needles upon said dial, a solenoid load switch controlling said loading means, a solenoid operated brake mounted upon said elevating motor, one of said contacts closing to energize the solenoids of said brake and said load switch in response to simultaneous zeroing of said needles, means for reversing said elevating motor means, a pair of snap switches one of which is responsive to the position of said platform, the other of which is responsive to application of load by said loading means controlling said reversing means, a pair of limit switches responsive to overtravel of said platform controlling said elevating motor, separate reversing means controlling said elevating motor, and switches controlling said separate means for operation of said elevating motor after operation of said limit switches.

3. In combination, a hardness testing machine having a platform to support a test specimen, means for elevating and lowering said platform, a penetrator device for applying load to said specimen, means for loading said penetrator device and a device for indicating the amount of penetration in the specimen of said penetrator, said indicating device including a dial and a pair of indicator needles pivoted upon said dial and control means for said machine comprising motor means for driving said elevating means connected to a source of electric power, photoelectric switch means responsive to the placing of a test specimen on said platform for energizing said drive motor, an electro-magnetically operated multiple switch, a pair of photoelectric cells in series with the solenoid of said multiple switch and responsive to zero position of said needles to energize and de-energize upon the shaft of said motor, solenoid operated loading switch controlling said loading means, contacts mounted upon said multiple switch for energizing said loading switch with said needles in zero position, a spring biased switch to energize the solenoid of said multiple switch in response to application of said load, switching contacts mounted upon said multiple switch disconnecting said drive motor when said load is applied, a solenoid operated reversing switch controlling the direction of operation of said drive motor, a first snap switch controlling the solenoid of said reversing switch, said first snap switch being responsive to application of load to said specimen to actuate the solenoid of said reversing switch, a solenoid positioned to operate said first snap switch, a second snap travel of said platform when said motor is deenergized by said limit switches.

FRITHIOF L. PEARSON. ALMON E. SPAULDING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,762,497 Wilson June 10, 1930 2,120,381 Troxell June 14, 1938 2,142,253 Nunan Jan. 3, 1939 2,333,747 Sklar Nov. 9, 1943 2,498,136 Rupley Feb. 21, 1950

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