US2384668A - Friction lock for screw threads - Google Patents

Description

9 R. ENSINGER ETAL FRICTION LOCK FQR SCREW THREADS Filed. April 8, 1944 0mg F IN VENTOR.

Patented Sept. 11, 1945 FRICTION LOCK FOR SCREW THREADS Ray Ensinger and James H. Foote, Detroit, Mich., assignors to George M. Holley and Earl Holley Application April 8, 1944,- Serial No. 530,210

2 Claims.

The object of this invention is to provide means for looking a threaded stud into a comparatively soft metallic casting.

It has heretofore been common practice to make a nut with a fiber inset spun into place, both nut and fiber being threaded on a bolt. When applying the same method to driving a stud into a casing, a different method of making the locking device has to be invented, because it is no longer possible to spin the casting over so as to engage the fiber insert.

In forcing the stud into the fiber insert, which is the preferred methods or in running an undesized tap into the fiber, the fiber must be Held from rotating and also must be clamped tightly against end movement.

Hence, the object of this invention is to provide an inexpensive means for holding a fiber washer against rotation and also against end thrust.

Figure I shows the parts ready for assembly.

Figure II shows the locating ring.

Figure III hows the fiber washer.

Figure IV shows in cross-sectional elevation the fiber ring locked in place.

Figure V shows the plan view looking up on Figure II.

In the figures: I is the casting; II is fiber washer; I2 is a steel locking ring shaped in cross section like the letter L. The ring I2 has a corner I 3 formed between the upper leg which makes an acute angle with the cylindrical extension I6, which forms the other leg of the L.

In Figure I the method of assembling is illustrated.

A punch I 4 has a short extension I5, which engages with and forms a pilot for the inside of the cylindrical extension I6 of the steel ring I 2. The drilled hole in the casting has a cylindrical portion II, which is a little larger than the diameter of the outside diameter of the fiber washer II. A portion I8 of the bore in the casting I 0 has a larger diameter than the bore l1 so that a shoulder I9 is formed between the bores I1 and I8, The punch I4 when driven home presses the corner I3 of the steel ring I2 into the shoulder I9 between the two bores I1 and I8 in the casting. The outside diameter of the punch is a little less than the diameter of the bore I8. An axial load on the corner I3 of the washer I2 causes a lateral force to be exerted by the periphery of the washer which is thus forced into the casting, which may be aluminum or any other casting softer than the material of the steel ring. The serrations on the lateral and axial legs of the L of the ring I2 shown in Figure revent the fiber ring from rotating. Finally the fiber is tapped with an undersized tap so that the fiber will grip the bolt or stud tightly. The serrations on the outside diameter of the ring I2 which engage with the opening Hi just above the shoulder I9 prevent the ring I2 being pushed during the threading operation.

Operation The fiber washer II is placed in the cylindrical portion II. The steel washer I2 is placed above the fiber washer and is guided by the cylindrical bore. The punch I4 then descends and is guided into the bore I8. The pilot I5 on the end of the punch enters the inside of the ring I2 and the shoulder of the punch engages with the corner I 3 of the ring I2. The pilot I5 on the end of the punch I4 being slightly smaller than the inside diameter of the cylindrical portion I6 of the steel ring I2, the punch I4 guides the ring into place. The steel ring I2 has a portion which is conical and when-pressure is applied to the upper edge I3 it becomes flat and therefore spreads laterally. The inside diameter I6 cannot be reduced as it is supported by the pilot I5. As a result, the outer edge of the fiat disc thus formed is forced laterally into the casting at a plane just above the shoulder I9, into the metal matrix.

At the same time, the lower edge of the ring I2 is pushed into the fiber Washer I I. The outer lateral edge of the steel ring I2 is serrated and the lower edge of the cylindrical portion I6 of ring I2 is also serrated. By these means, when these two metal edges of the ring I2 are forced, one down into the fiber, and the other, laterally into the casting, the fiber is thus locked in place and cannot rotate nor can it be pushed out.

Subsequently a thread is formed on the fiber by means of an undersized tap or the bolt itself when forced up from the bottom of the opening will form a thread in the fiber.

The pilot I5 prevents the inner diameter I6 from interfering with the top of the thread and the locking ring being forced into the wall of the opening in the casting will not be pushed out. The serrations on the locking ring prevent the fiber disc rotating. Hence, a tight fiber thread is formed as an extension to the thread in the casting I0.

What we claim is:

1. In a casting of relatively soft metal, a fiber bushing, and L shaped locking ring having an acute angle and serrated edges and made of relatively hard metal, the cylindrical portion of the L being embedded in the fiber, the transverse portion of the L being forced into locking engagement with the relatively soft metal by the enlargement of the acute angle of the ring.

2. A fiber locking ring embedded in an opening in a relatively soft metal matrix, a relatively hard metal ring having an L shaped cross section with serrated edges, the serrrated edge of the axial portions engaging with the fiber washer, and the radial portion engaging with the metal matrix.

RAY ENSINGER. JAMES H. FOOTE.

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