Lock nut

A lock nut for connecting a joint having a threaded connector has a first nut member which is engageable with a threaded connector and is axially displaceable, a second nut member which is engageable with the first nut member and is rotatable about an axis, a third nut member which is non-rotatably but axially displaceably connected with the first nut member and has a substantially smooth surface over which the second nut member moves during rotation, so that when the second nut member is rotated about the axis against the smooth surface of the third nut member, the first nut member is displaced axially to apply a load to the threaded connector and to tighten the lock nut, and a locking element which non-rotatably connects the first and second nut members with one another after tightening of the lock nut.

BACKGROUND OF THE INVENTION 
The present invention generally relates to lock nuts. 
Lock nuts are known in the art and widely utilized in industry. Some lock 
nuts require a firm connection of the nut with the bolt. Other lock nuts 
require a firm connection with the flange within which the bolt is 
screwed. Also, lock nuts that are provided with a two-piece washer 
slidable in one direction relative to one another and provided with 
rippled surfaces to abut against the flange surface on one side and 
against the nut bearing surface on the other side. Also, a lock nut is 
known which is designed so as to eliminate rotation of one of the nut 
members after tightening of the lock nut as disclosed in my U.S. Pat. No. 
5,622,465. The above mentioned lock nut can be further improved. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of present invention to provide a lock nut 
which is a further improvement of existing lock nuts. 
In keeping with these objects and with others which will become apparent 
hereinafter, one feature of the present invention resides, briefly stated, 
in a lock nut to connect a joint having a threaded connector, comprising a 
first nut member which is engageable with the threaded connector and is 
axially displaceable, a second member which is engageable with the first 
nut member and is rotatable about an axis, a third nut member which is 
connected non-rotatably but axially displaceably with the first nut member 
and which has one substantially smooth surface over which the second nut 
member moves during rotation, so that when the second nut member is turned 
about the axis against the surface of the third nut member, and the first 
nut member is displaced axially to apply a load to the threaded connector, 
and therefore the lock nut is sufficiently tightened, and locking means 
which eliminates rotation of the second nut member by non-rotatably 
connecting the first nut member with the second nut member. 
The novel features which are considered as characteristic for the present 
invention are set forth in particular in the appended claims. The 
invention itself, however, both as to its construction and its method of 
operation, together with additional objects and advantages thereof, will 
be best understood from the following description of specific embodiments 
when read in connection with the accompanying drawings.

DESCRIPTION OF PREFERRED EMBODIMENTS 
A lock nut in accordance with the present invention shown in the drawing 
has a washer which is identified as a whole with reference numeral 1. The 
washer is ring-shaped and has a lower surface 1a which is substantially 
rough and an upper surface 1b which is substantially smooth. The surfaces 
1a and 1b are spaced from one another in an axial direction. The washer 
further has an inner surface which has a polygonal formation formed for 
example by a plurality of inner splines 1c. The splines extend in an axial 
direction and are spaced from one another in a circumferential direction. 
The rough surface 1a can be made in many different ways, for example by a 
plurality of ripples. The washer 1 forms a third nut member. 
The lock nut further has a first nut member identified as a whole with 
reference numeral 2. The first nut member 2 is formed as a sleeve. It has 
inner thread means 2a engageable with outer thread means of a threaded 
connector of a joint, for example a bolt 4. It also has outer thread means 
2b. Furthermore, it is provided with a polygonal formation 2c which is 
engageable with the polygonal formation 1c of the third nut member 1, so 
that the third nut member 1 and the first nut member 2 are connected with 
one another non-rotatably by displaceably in an axial direction relative 
to one another. The polygonal formation 2c can be formed by a plurality of 
splines which extend in an axial direction and are spaced from one another 
in a circumferential direction. Finally, the first nut member 2 has 
another polygonal formation 2d provided in the upper part on its inner 
surface. This polygonal formation also can be formed by a plurality of 
splines which extend in an axial direction and are spaced from one another 
in a circumferential direction. 
The lock nut further has a second nut member which is identified as a whole 
with reference numeral 3. The second nut member is formed as a sleeve. It 
has inner thread means 3a which is engageable with the outer thread means 
2b of the inner nut member 2. It further has an additional polygonal 
formation 3b which can be formed by a plurality of castellations extending 
in an axial direction and spaced from one another in a circumferential 
direction. 
The lock nut further has a locking element which is identified as a whole 
with reference numeral 6. The locking element 6 is formed as a cap and is 
provided with two groups of locking means. The locking means of the first 
group is formed as a polygonal formation including a plurality of splines 
6a formed on an inner projection of the locking element 6 so as to extend 
in an axial direction and to be spaced from one another in a 
circumferential direction. The locking means of the second group include a 
polygonal formation formed by a plurality of castellations 6b provided on 
an inner surface of the locking element and spaced from one another in a 
circumferential direction. 
The lock nut in accordance with the present invention operates in the 
following manner: 
The lock nut including the first nut member 2, the second nut member 3 and 
the third nut member 1 is applied onto the threaded connector, in 
particular on the bolt 4 by screwing the first nut member 2 onto the bolt. 
Then, the castellations 3b of the second nut member 3 are engaged by a 
tool and the second nut member is turned around its axis, while the first 
nut member 2 is prevented from rotation by being held with a tool engaging 
in the splines 2d. During turning of the second nut member 3, it slides 
with its lower surface against the smooth surface 1b of the third nut 
member 1, the first nut member 2 is displaced axially upwardly and 
tightens the bolt 4, the lower rough surface 1a of the third nut member 
embeds in the upper surface of the other part of the joint, in particular 
a flange 5, and the third nut member 1 together with the first nut member 
2 do not turn during this process. When the lock nut is sufficiently 
tightened, the tool is disengaged and the locking element 6 is fitted over 
the nut members, so that the castellations 6b of the locking element 6 
engage with the castellations 3b of the second nut member 3, and the 
splines 6a of the locking element 6 engage with the splines 2d of the 
second nut member 2. As a result, all parts of the lock nut become 
non-rotatably connected with one another and the lock nut can not turn 
relative to the flange 5. 
It will be understood that each of the elements described above, or two or 
more together, may also find a useful application in other types of 
constructions differing from the types described above. 
While the invention has been illustrated and described as embodied in lock 
nut, it is not intended to be limited to the details shown, since various 
modifications and structural changes may be made without departing in any 
way from the spirit of the present invention. 
Without further analysis, the foregoing will so fully reveal the gist of 
the present invention that others can, by applying current knowledge, 
readily adapt it for various applications without omitting features that, 
from the standpoint of prior art, fairly constitute essential 
characteristics of the generic or specific aspects of this invention. 
What is claimed as new and desired to be protected by Letters Patent is set 
forth in the appended claims: