US2114854A - Material testing machine - Google Patents

Description

, 1938. R. R. MOORE MATERIAL TESTING MACHINE Aprii w Filed May 14, 1935 INVENTOR Patented Apr. 19, 1938 UITE sr'rss ATENT FEE 8 Claims.

This invention relates to material testing machines of the type used for testing the fatigue of materials, and is an improvement over the disclosure in my prior Patent No. 1,608,804 which issued November 30, 1926.

An object of this invention is to provide a machine of this character which will not unduly heat up during the testing operation.

Another object of this invention is to provide a machine of this character which is so constructed that the testing time is shortened, thus giving a greater capacity to the machine.

A further object of this invention is to provide a testing machine which may operate at relatively high speeds without becoming unduly heated and the parts of which will not unduly wear by reason of the high speed.

A still further object of this invention is to provide a high speed fatigue testing machine which includes a cooling means so disposed with respect to the machine as to maintain a uniform coolness on the machine irrespective of the speed thereof.

Still another object of this invention is to provide a machine of this character which is so constructed that it may be properly lubricated at the desired speeds and which embodies features whereby the lubricant will not be centrifu gally thrown out of the machine, and whereby the lubricant will not unduly thin out or the bearings overheat causing seizing, sticking or freezing of the moving parts as is the case with machines not embodying the cooling means included with this invention.

A further object of this invention is to provide a novel coupling means between the power member and the spindle or specimen draw bar whereby vibration is substantially eliminated, freedom of deflection of the housing is permitted and wear of the coupling is eliminated under high speeds.

With the above objects in view, and with other objects and advantages which will be more fully set forth in the following description and in the claims, reference is had to the accompanying drawing, in which Figure 1 is a detail side elevation, partly broken away and in longitudinal section, of a fatigue testing machine constructed according to an embodiment of this invention.

Figure 2 is a top plan view of the device with the top of the air tunnel or shield removed.

Figure 3 is a sectional View taken on the line 3-3 of Fig. 1.

Figure 4 is a sectional view taken on the line 4-4 of Fig. 1.

Figure 5 is a sectional view taken on the line 55 of Fig. 1.

Figure 6 is a sectional view taken on the line 6 6-6 of Fig. 1.

Figure '7 is an enlarged fragmentary longitudinal sectional view showing a portion of the novel coupling between the specimen draw bar and the flexible connecting link.

Figure'8 is any end elevation of the draw bar lock nut.

Figure 9 is an enlarged longitudinal sectional view of the connecting link at the driving end thereof, and 15 Figure 10 is a detail side elevation of a modified form of air tunnel or shield.

Referring now to the drawing, the numeral l5 designates generally a journal housing, and the numeral l6 designates a second journal housing disposed in axial alinement with the housing l5 and spaced therefrom. These two housings l5 and it are identical in construction, and it will, therefore, be understood that the following description of the journal housing l5 and the parts associated therewith will apply equally as well to the housing I6 with its associated parts.

A hollow journal' I? is rotatably mounted within the journal housing l5, of suitable length and diameter so that the journal i1 may be removed and the hereinafter described parts mounted therein. The housing 15 has an oil chamber or reservoir H8 in substantially the center thereof, and adjacent each end of the journal I! there are also end chambers l9 and 20. An oil channel 2| extends along the bottom of the housing l5 and communicates with the two end chambers l9 and 20 and also with the oil reservoir l8. Oil rings 22 are disposed loosely about the journal I1 and dip into the oil channel 2| so that the bearing surface of the journal I! will be lubricated during the rotation thereof. If desired the rings 22 can first be inserted into the housing and thereafter the journal IT inserted. Preferably a sight opening 23 is provided on each side of the reservoir l8, and this opening covered by a transparent member or the like sothat the level of oil in the reservoir can be readily determined.

The journal I! at its driven end is provided with a tapered opening within which the tapered end 24 of a specimen 25 is adapted to engage. This tapered or inner end 24 of the specimen is threaded onto the outer end of the draw bar 26, which extends longitudinally through the journal 55 I! and is of a diameter slightly less than the interior diameter of the journal I1.

The inner end of the journal I"! is threaded as at 27, and a nut 28 having a bore therethrough threadedly engages the threads 21. The inner threaded end 29 of the draw bar 26 is flattened on opposite sides to fit into the flattened portions 3! of the nut 28, which is shown in detail in Fig. 8, and a draw bar tightening nut 30 engages the threads 26. The tightening nut 30 has a reduced inner end 3! which is fixed to the outer end of a relatively flexible driving cable 32. Preferably the outer end of the drive link 32 is sweated or otherwise fixedly secured within the reduced end 3| of the nut 30.

The inner end of the drive link 32 is fixed within a knuckle or threaded plug 36, and this knuckle 36 engages the interior threads of a driving sleeve 36 secured to a suitable power member 35, and contacts at its inner end with a threaded plug or spacer 33 within the sleeve 34. This power member 35 is preferably an electric motor capable of extremely high speeds, that is upwards of about 10,000 R. P. M. By turning the plug or knuckle 38 up against the spacer 33 tension is applied to the cable or drive link 32, and this cable 32 pulls the journal or spindle i'l until the first oil slinger or annulus 38 is clear of the end of the bearing. Contact of the bearing and the first oil slinger 38 would create friction and generate heat which it is desired to avoid in this machine so as to prevent sticking or freezing of the journal IT.

The journal i1 is provided adjacent each end with a plurality of annular ribs or oil slingers 38 which are disposed within the adjacent end chambers I9 and 23, and these ribs 38 act not only as a cooling means or heat dissipating means for the journal H, but also as a means to centrifugally throw oif any oil which may fiow out between the journal l1 and the housing IS. The oil thrown against the surface of the chambers l9 and 20 will flow back to the oil reservoir is through the bottom channel 2|.

An end plate 39 having an axial opening 40 is -'threaded into an end of the housing I5, and is provided with recesses 4i for the reception of a suitable tool. There are two of these end plates 33, one at each end of the housing l5, and these plates 39 prevent the oil in the end chambers from leaking out of the housing l5. The inner end of the draw bar 26 terminates inwardly of the end plate 39, and the reduced nut portion 3! extends through the axial opening 40, so that the entire journal I l and the draw bar 26 are contained within the housing l5. This construction permits a more thorough lubrication of the journal ll and prevents leakage of any oil out of the housing.

The housing I5 is provided with a pair of opposed trunnions l2 rotatably mounted in bearings 43. The bearings 43 are slidably mounted on guides M carried by standards or supporting means 65. These trunnions 42 and bearings 43 fit in notches in the guides 34 on tunnel GB, and are similar to like parts in my prior patent, and are constructed to prevent lateral movement of the housing IS without permitting longitudinal movement. In respect to housing 10 the trunnions (l2 and bearings 43 sit on top of the guide 4 and are constructed to prevent lateral movement of the housing It but does permit longitudinal movement of this housing to accommodate variations in the test specimen.

A load applying yoke 46 engages the housing I5 at a predetermined point relative to the trunnions 42 and extends downwardly between the supports so that a suitable load may be applied to the yoke.

It will be understood that a tachometer may be connected to one of the journals, to the side of the motor 35 opposite from the sleeve 34, or connected in any desired manner to this device so that the operation of the tachometer will. not affect the results of the specimen.

In a device of this kind, due to the high speed of the journals a considerable amount of heat is generated, and in order to maintain the housing 25 in a cool condition so as to prevent thinning of the oil and consequent loss thereof, the housing 55 is provided with a plurality of cooling fins 41 which will act to dissipate heat and thus prevent sticking or freezing of the journal in the bearing. A further advantage is that when the housing is being cooled, the journal is cooled thereby, and the journal is thereby prevented from expanding and seizing in the bearing. Furthermore, there is less, if any, heat transmitted to the specimen. While these fins 4'! will dissipate a quantity of heat, it has been found from experiments that proper cooling of the housing I5 can be effected by fan action which is augmented or controlled by enclosing the housing l5 in air tunnel or shield generally designated as 48. Movement of air through the tunnel 48 is effected by means of a fan 49 which is secured to the driving shaft or sleeve 34.

The swirling or spiralling of the air through the tunnel 48 is prevented by means of fins 50 secured to a tube or shield 50 disposed about the driving link 32. This tube or shield 50 will prevent the air from striking the inner end of the housing l5 and will guide the air toward the hous ing.

In order that the movement of the air in the 40 air tunnel Q8 will not be impeded by the inner end of the housing 56, a shield Si is disposed about the specimen 25 between the abutting ends of the two housings i5 and i6. Preferably the shield or tunnel 4 8 is constructed in two parts, an upper part 52 and a lower part 53, with the upper part 52 removably mounted on the lower part 53. The bearings Q3 and the supports 3 are preferably tapered at each end so as to prevent any impedance to the movement of air. The air within the reservoir l8 above the top of the oil is drawn out by providing a vent 54 of suitable construction which is so constructed that hot air is drawn out of the reservoir l8 by suction in the movement of the air in the housing i 5.

The air tunnel 58 is disclosed as being substantially cylindrical in construction with the fan 49 mounted in the inner end thereof. In Figure 10 there is disclosed a modified form of air tunnel or shield 63 which is provided at its inner end with a flared portion 48 so that a larger fan may be used to increase the flow of air through the tunnel. By giving the shield a Venturi contour a more efiicient air flow is produced with the same size fan as shown in Fig. 1, since the Venturi contour produces an increased velocity of air through the housing 48.

In the use and operation of this testing machine, the two draw bars 26 are secured to the opposite ends of the specimen 25 and tightened in their respective journals l! by means of the tightening nuts 30. The innermost nut 30 is secured to the flexible driving link or shaft 32, which is in turn secured to and placed under tension in the driving sleeve 34.

The power member 35 is then started, and at the same time the fan 49 will force air through the tunnel 48 at a rate dependent upon the speed of the power member 35. As has been heretofore stated, the power member 35 is preferably operated at an exceedingly high rate of speed so that a considerable air velocity will be developed within the tunnel 48, and the heat generated by the journals I! will be dissipated by means of the moving air passing longitudinally of the longitudinal fins 41. As the degree of heat generated will be dependent upon the speed of the power member 35, by connecting the fan 49 directly to' the power member 35 the air velocity will be proportionate to the speed of the power member. The machine hereinbefore described is capable of operating at a higher rate of speed than the machine disclosed in my prior patent, and for this reason the time of the testing operation is shortened very considerably, and the same machine is capable of performing the testing operations indefinitely without appreciable wear on the parts thereof by reason of the cooling means which prevents overheating of the parts and the failure of the lubricating system. As the device herein disclosed is maintained cool at all times there is substantially no loss of oil so that extremely close bearing clearances may be provided and the vibration of the parts prevented even at very high speeds.

The removal of hot air from the housing accomplishes three functions important to the successful operation of the machine: it cools the housing by removing the hot air; it helps to prevent oil from leaking out of the ends of the housings, since it has been found that when no outlet is provided for the air in the housing the pressure of the expanding air caused by heating up forces oil out of the ends of the housings; and the suction of the hot air from the oil reservoir prevents any dirt or dust from mixing with the oil so that the cooling system also forms a successful dirt seal for the housings.

It is obvious that various changes and modifications may be made in the details of construction and design of the above specifically described embodiment of this invention without departing from the spirit thereof, such changes and modifications being restricted only by the scope of the following claims.

What is claimed is:

1. A testing machine comprising a pair of journal housings disposed in spaced apart relation, a hollow journal for each housing and rotatable therein, means extending through the journals for holding a specimen in the space between the housings and in axial alinement with the journals, a tensionable connecting link for connecting one of said journals to a source of power supply for rotation thereby, means for tensioning said link, a lubricating means for each journal, means for enclosing the journals in the housings to prevent leakage of the lubricant, and means for cooling the housings proportionate to the speed of rotation of the journals, said latter means including supporting means for said housings.

2. A testing machine comprising a pair of journal housings disposed in spaced apart relation, a hollow journal for each housing and rotatable therein, means extending through the journals for holding a specimen in the space between the housings and in axial alinement with the journals, a driving link connected to one of said journals and extending axially and outwardly of one of said housings, lubricating means for said journals, an air tunnel about said housings, means for supporting said housings in said tunnel, means at one end of the tunnel connected to said link for forcing air longitudinally through the tunnel proportionate to the speed of the journals, and means about the specimen for preventing impedance of air between the housings.

3. A testing machine comprising a pair of journal housings disposed in spaced apart relation, a hollow journal for each housing and rotatable therein, means extending through the journals for holding a specimen in the space between the housings and in axial alinement with the journals, each of said journals having a length less than the length of the housings, a driving link connected to one of said journals and extending axially and outwardly of one of said housings, lubricating means for said journals, an air tunnel about said housings, means for supporting said housings in said tunnel, means for forcing air longitudinally through said tunnel proportionate to the speed of the journals, means for maintaining a straight draft of air through the housings, and a shield disposed between the housings about the specimen and within the tunnel to prevent contact of the moving air with the specimen and to prevent the moving air from striking the inner end of the outermost of the housings.

4. A testing machine comprising a pair of journal housings disposed in spaced apart relation, a hollow journal for each housing and rotatable therein, means extending through the journals for holding a specimen in the space between the housings and in axial alinement with the journals, each of said journals having a length less than the length of the housings, lubricating means for said journals, end plates for each housing, a pair of oil receiving chambers one adjacent each end of each housing, ribs secured to each journal within each chamber, means for connecting one of said journals to a source of power supply, and means for cooling said housings proportionate to the speed of the journals, said means including supporting means for said housings.

5. A fatigue machine comprising in combination, a pair of spaced apart journal housings, a pair of journals one in each housing, means carried by the journals for holding a specimen between the housings for rotation with the journals, a flexible connecting link for connecting one pf said journals to a driving means, an air tunnel about said housings, means for supporting the housings for movement within said air tunnel, means connected to said link and rotatable therewith for forcing air through the tunnel proportionate to the speed of said journals and air guiding means in the tunnel between said one journal and said latter means.

6. A testing machine comprising in combination, an. air tunnel, a pair of journal housings disposed in spaced apart relation within said tunnel, means for supporting the housings for movement within said air tunnel, a hollow jour nal rotatable in each housing, means extending through the journal for holding a specimen in the space between the housings and in axial alinement with the journals, a link connecting one of said journals to a source of power supply for rotation thereby, means for tensioning said link, a fan connected to said link and disposed at one end of the tunnel for forcing air longitudinally of the tunnel proportionate to the speed of the journals and air guiding means in said tunnel between said one journal and said fan.

7. A testing machine comprising in combination, a pair of journal housings disposed in spaced apart relation, a hollow journal for each housing and rotatable therein, means extending through the journals for holding a specimen in the space between the housings and in axial alinement with the journals, a link for connecting one of said journals to a source of power supply for rotation thereby, means for tensioning said link, heat exchanging fins carried by each housing, a fan connected to said power supply and said link for forcing air longitudinally of the housings proportionate to the speed of the journals, means for confining the draft of air about said housings for cooling thereof, and air directing means within said latter means.

8. A testing machine comprising in combination, a pair of journal housings disposed in spaced apart relation, a hollow journal for each housing and rotatable therein, means extending through the journals for holding a specimen in the space between the housings and in axial alinement with the journals, a tensionable link connecting one of said journals to a source of power supply for rotation thereby, means for tensioning said link, heat dissipating fins carried by the housings, a fan connected to said power supply and said link for forcing air longitudinally of the housings proportionate to the speed of the journals, a substantially cylindrical tunnel disposed in spaced relation about said housings, means disposed between the innermost housing and the fan for directing the moving air in a straight path within the tunnel, and supporting means for said housings.

RICHARD R. MOORE.

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