U.S. patent application number 14/793768 was filed with the patent office on 2017-01-12 for slack adjuster for railcar brake.
The applicant listed for this patent is Amsted Rail-Faiveley LLC. Invention is credited to Michael E. Ring.
Application Number | 20170008539 14/793768 |
Document ID | / |
Family ID | 57685707 |
Filed Date | 2017-01-12 |
United States Patent
Application |
20170008539 |
Kind Code |
A1 |
Ring; Michael E. |
January 12, 2017 |
SLACK ADJUSTER FOR RAILCAR BRAKE
Abstract
A slack adjuster for railroad car braking system is provided.
The slack adjuster includes a first jaw positioned at a first end
of the slack adjuster and a second jaw positioned at a second end
of the slack adjuster. A rod assembly is attached to the first jaw
and a tube is attached to the second jaw. A nut assembly is
provided for transferring a force between the rod assembly and the
tube. One or more components configured to bear an axial load of
the slack adjuster are attached to the tube by crimping at least a
portion of the tube into a groove defined in an outer surface of
such component.
Inventors: |
Ring; Michael E.; (Lake
Village, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Amsted Rail-Faiveley LLC |
Greenville |
SC |
US |
|
|
Family ID: |
57685707 |
Appl. No.: |
14/793768 |
Filed: |
July 8, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B61H 15/0057 20130101;
F16D 65/66 20130101 |
International
Class: |
B61H 15/00 20060101
B61H015/00 |
Claims
1. A slack adjuster for a railroad car braking system defining an
axial direction and a circumferential direction, the slack adjuster
comprising: a first jaw; a rod assembly attached to the first jaw;
a nut assembly having at least a portion rotatably engaged with the
rod assembly; a tube attached to the nut assembly and extending
generally along the axial direction between a first end and a
second end, the tube enclosing at least a portion of the rod
assembly; and a second jaw including a base attached to the second
end of the tube, the base of the second jaw defining a groove
therein extending generally along the circumferential direction, at
least a portion of the tube crimped into the groove in the base of
the second jaw attaching the tube to the base of the second
jaw.
2. The slack adjuster of claim 1, wherein the base of the second
jaw defines a central opening and is a solid component between the
central opening and the groove, free from any opening or holes.
3. The slack adjuster of claim 1, wherein the groove in the base of
the second jaw defines an inner edge having a radius greater than
or equal to about 1/8th of an inch.
4. The slack adjuster of claim 1, wherein the nut assembly includes
a nut defining a threaded opening rotatably engaged with a threaded
portion of the rod assembly, a first bearing collar, and a second
bearing collar, wherein the first and second bearing collars are
disposed on opposite sides of the nut along the axial direction for
constraining the nut along the axial direction of the slack
adjuster relative to the tube,
5. The slack adjuster of claim 4, wherein the first bearing collar
defines a groove in an outer surface extending generally along the
circumferential direction, and wherein at least a portion of the
tube is crimped into the groove in the first bearing collar
attaching the tube to the first bearing collar.
6. The slack adjuster of claim 5, wherein the first bearing collar
defines a center opening through which a portion of the rod
assembly extends, and wherein the first bearing collar is a solid
component between the center opening and the groove, free from any
opening or holes.
7. The slack adjuster of claim 5, wherein the groove in the first
hearing collar defines an inner edge having a radius greater than
or equal to about 1/8th of an inch.
8. The slack adjuster of claim 5, wherein the second bearing collar
also defines a groove in an outer surface extending generally along
the circumferential direction, and wherein at least a portion of
the tube is crimped into the groove in the second bearing collar
attaching the tube to the second bearing collar.
9. The slack adjuster of claim 8, wherein the second bearing collar
defines a center opening through which a portion of the rod
assembly extends, and wherein the second bearing collar is a solid
component between the center opening and the groove, free from any
opening or holes.
10. The slack adjuster of claim 8, wherein the groove in the first
bearing collar defines an inner edge having a radius greater than
or equal to about 1/8th of an inch, and wherein the groove in the
second bearing collar also defines an inner edge having a radius
greater than or equal to about 1/8th of an inch.
11. The slack adjuster of claim 4, further comprising a pawl box
including at least one locator tab and at least one coupling
projection, wherein the tube defines at least one pawl opening
adjacent to the nut of the nut assembly and at least one locator
opening positioned adjacent to the at least one pawl opening,
wherein the pawl box is attached to the tube by positioning the
pawl box over the at least one pawl opening such that the at least
one locator tab of the pawl box extend into the at least one
locator opening and by forming the at least two coupling
projections of the pawl box around an outer surface of the
tube.
12. The slack adjuster of claim 1, further comprising an end cap
defining a groove extending generally along the circumferential
direction, at least a portion of the rod assembly slidably
extending through the end cap, wherein at least a portion of the
tube is crimped into the groove in the end cap attaching the tube
to the end cap.
13. A slack adjuster for a railroad car braking system defining an
axial direction and a circumferential direction, the slack adjuster
comprising: a first jaw and a second jaw, the first jaw positioned
at a first end of the slack adjuster along the axial direction and
the second jaw positioned at a second end of the slack adjuster
along the axial direction; a rod assembly attached to the first jaw
and extending generally along the axial direction; a tube attached
to the second jaw and also extending generally along the axial
direction; and a nut assembly configured to transfer a force
between the rod assembly and the tube, the nut assembly including a
first bearing collar defining a groove therein extending generally
along the circumferential direction, at least a portion of the tube
crimped into the groove in the first bearing collar attaching the
tube to the first bearing collar.
14. The slack adjuster of claim 13, wherein the nut assembly
further includes a second bearing collar also defining a groove
therein extending generally along the circumferential direction,
wherein at least a portion of the tube is crimped into the groove
in the second bearing collar attaching the tube to the second
bearing collar.
15. The slack adjuster of claim 13, wherein the second jaw includes
a base defining a groove therein extending generally along the
circumferential direction, wherein at least a portion of the tube
is crimped into the groove in the base of the second jaw attaching
the tube to the base of the second jaw.
16. A method for manufacturing a slack adjuster for a railroad car
braking system, the slack adjuster defining an axial direction, the
method comprising: attaching a first jaw to a rod assembly;
positioning a nut assembly over a threaded portion of the rod
assembly; attaching the nut assembly to a tube extending generally
along the axial direction such that at least a portion of the nut
assembly is fixed along the axial direction relative to the tube;
and attaching the tube to a base of a second jaw by crimping a
portion of the tube into a groove defined in the base of the second
jaw, fixing the base of the second jaw to the tube.
17. The method of claim 16, wherein the nut assembly includes a nut
defining a threaded opening rotatably engaged with the threaded
portion of the rod assembly, a first bearing collar, and a second
bearing collar, wherein attaching the nut assembly to the tube
includes attaching the nut assembly to the tube by crimping at
least a portion of the tube into a groove defined in an outer
surface of the first bearing collar and crimping at least a portion
of the tube into a groove defined in an outer surface of the second
bearing collar.
18. The method of claim 16, wherein attaching the tube to the base
of the second jaw by crimping a portion of the tube into the groove
defined in the base of the second jaw includes crimping a portion
of the tube into the groove defined in the base of the second jaw
using a plurality of crimp dies, wherein each of the plurality of
crimp dies includes a crimping portion, and wherein each of the
crimping portions define a crimping edge having a radius of at
least 1/8th of an inch.
19. The method of claim 16, further comprising: reconditioning the
slack adjuster, wherein reconditioning the slack adjuster includes
removing the second jaw from the tube by shearing off the portion
of the tube crimped into the groove in the base of the second jaw
with a plurality of crimp dies.
20. The method of claim 16, further comprising: attaching a pawl
box to the tube, wherein attaching the pawl box to the tube
includes positioning the pawl box over a pawl opening defined in
the tube such that at least one locator tab of the pawl box extends
into at least one locator opening defined in the tube, and wherein
attaching the pawl box to the tube further includes forming a pair
of coupling projections around an outer surface of the tube.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to a slack adjuster
for a railway car braking system.
BACKGROUND OF THE INVENTION
[0002] Railway cars are widely used for transportation of goods and
passengers throughout the United States and abroad. Railway cars
generally include one or more truck assemblies including a
plurality of specially designed wheels for traveling along a vast
infrastructure of railway car tracks. Braking systems are generally
disposed between adjacent pairs of wheels for facilitating the
stopping or slowing down of the railway car.
[0003] A braking system can generally include a pair of brake
assemblies corresponding to a pair of trucks supporting a railway
car. Each of the brake assemblies includes leading and trailing
brake beam assemblies, each with a pair of brake heads having brake
shoes for contact with an outer periphery of the wheels when the
leading and trailing brake beam assemblies are moved away from one
another. Commonly, an air cylinder is provided between the pair of
brake assemblies in the braking system for generating the force
that causes such movement. The air cylinder or another actuator is
connected to each of the pair of brake assemblies and respective
leading and trailing brake beam assemblies through a linkage system
including various rods and levers.
[0004] Many braking systems further include assemblies
conventionally known as slack adjusters for adjusting the movement
of the leading and trailing brake beam assemblies of the respective
brake assemblies as required. In particular, slack adjusters
compensate for brake shoe wear and wheel wear by adjusting its
length. Typically, a slack adjuster is built into one of the rods
in linkage system.
[0005] Accordingly, the slack adjuster must be capable of
withstanding a large amount of force. For example, certain slack
adjusters must be capable of withstanding more than of 20,000 to
30,000 pounds of force during operation. In order to accommodate
such a large amount of force, the load bearing components of the
slack adjuster are typically connected using intricate bolting
systems. With such systems, however, the parts must be thicker than
may otherwise be necessary to accommodate the holes for the bolts,
and each of the holes must he precisely cut.
[0006] Therefore, an improved system or method for attaching
components of a slack adjuster capable of bearing a large amount of
force would be useful.
BRIEF DESCRIPTION OF THE INVENTION
[0007] Aspects and advantages of the invention are set forth below
in the following description, or may be obvious from the
description, or may he learned through practice of the
invention.
[0008] In one exemplary embodiment of the present invention, a
slack adjuster is provided for a railroad car braking system. The
slack adjuster defines an axial direction and a circumferential
direction. The slack adjuster includes a first jaw, a rod assembly
attached to the first jaw, a nut assembly having at least a portion
rotatably engaged with the rod assembly, and a tube attached to the
nut assembly. The tube extends generally along the axial direction
between a first end and a second end. Additionally, the tube
encloses at least a portion of the rod assembly. The slack adjuster
additionally includes a second jaw including a base attached to the
second end of the tube. The base of the second jaw defines a groove
therein extending generally along the circumferential direction, at
least a portion of the tube crimped into the groove in the base of
the second jaw attaching the tube to the base of the second
jaw.
[0009] In another exemplary embodiment of the present invention, a
slack adjuster is provided for a railroad car braking system
defining an axial direction and a circumferential direction. The
slack adjuster includes a first jaw and a second jaw. The first jaw
is positioned at a first end of the slack adjuster along the axial
direction and the second jaw is positioned at a second end of the
slack adjuster along the axial direction. The slack adjuster
additionally includes a rod assembly attached to the first jaw and
extending generally along the axial direction, a tube attached to
the second jaw and also extending generally along the axial
direction, and a nut assembly configured to transfer a force
between the rod assembly and the tube. The nut assembly includes a
first bearing collar defining a groove therein extending generally
along the circumferential direction. At least a portion of the tube
is crimped into the groove in the first bearing collar, attaching
the tube to the first bearing collar.
[0010] In an exemplary aspect of the present disclosure, a method
for manufacturing a slack adjuster for a railroad car braking
system is provided. The slack adjuster defines an axial direction
and the method includes attaching a first jaw to a rod assembly,
positioning a nut assembly over a threaded portion of the rod
assembly, and attaching the nut assembly to a tube extending
generally along the axial direction such that at least a portion of
the nut assembly is fixed along the axial direction relative to the
tube. The method also includes attaching the tube to a base of a
second jaw by crimping a portion of the tube into a groove defined
in the base of the second jaw, fixing the base of the second jaw to
the tube.
[0011] Those of ordinary skill in the art will better appreciate
the features and aspects of such embodiments, and others, upon
review of the specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] A full and enabling disclosure of the present invention,
including the best mode thereof to one skilled in the art, is set
forth more particularly in the remainder of the specification,
including reference to the accompanying figures, in which:
[0013] FIG. 1 provides a braking system in accordance with an
exemplary embodiment of the present disclosure installed in an
exemplary railway car truck.
[0014] FIG. 2 provides a perspective view of a slack adjuster in
accordance with an exemplary embodiment of the present
disclosure.
[0015] FIG. 3 provides a close up exploded view of a portion of the
exemplary slack adjuster of FIG. 2, prior to installation of a pawl
box.
[0016] FIG. 4 provides a close-up perspective view of a portion of
the exemplary slack adjuster of FIG. 2, with the pawl box
installed.
[0017] FIG. 5 provides a side, cross-sectional view of a center
portion of the exemplary slack adjuster of FIG. 2.
[0018] FIG. 6 provides a perspective view of a first bearing collar
of a nut assembly of the exemplary slack adjuster FIG. 2.
[0019] FIG. 7 provides a perspective view of a second bearing
collar of the nut assembly of the exemplary slack adjuster of FIG.
2
[0020] FIG. 8 provides a perspective view of a second end of the
exemplary slack adjuster of FIG. 2.
[0021] FIG. 9 provides a side, cross-sectional view of the second
end of the exemplary slack adjuster of FIG. 2.
[0022] FIG. 10 provides a side, cross-sectional view of a crimp die
for crimping a portion of the tube of the exemplary slack adjuster
of FIG. 2 into a groove defined in a component of the exemplary
slack adjuster of FIG. 2.
[0023] FIG. 11 provides a flow diagram of a method for
manufacturing a slack adjuster in accordance with an exemplary
aspect of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0024] Reference now will be made in detail to embodiments of the
invention, one or more examples of which are illustrated in the
drawings. Each example is provided by way of explanation of the
invention, not limitation of the invention. In fact, it will be
apparent to those skilled in the art that various modifications and
variations can be made in the present invention without departing
from the scope or spirit of the invention. For instance, features
illustrated or described as part of one embodiment can be used with
another embodiment to yield a still further embodiment. Thus, it is
intended that the present invention covers such modifications and
variations as come within the scope of the appended claims and
their equivalents.
[0025] Referring now to the Figures, FIG. 1 provides a braking
system 50 in accordance with an exemplary embodiment of the present
disclosure. The braking system 50 is generally referred to as a
body mounted brake system, configured for attachment to a body of a
railway car (not shown). It should be appreciated, however, that in
other exemplary embodiments, the braking system 50 may instead he
what is generally referred to as a truck mounted brake system
mounted to a railway car truck.
[0026] As shown, the braking system 50 generally includes a leading
braking system 52 and a trailing braking system 54 spaced from one
another along a longitudinal direction L. The leading braking
system 52 may be configured with a leading railway car truck having
a plurality of wheels and mounted under the railway car (not
shown), and similarly the trailing braking system 54 may be
configured with a trailing railway car truck having a plurality of
wheels and also mounted under the railway car (not shown). The
wheels of the leading and trailing railway car trucks may be
configured to engage an infrastructure of railway car tracks. As
used herein, the terms "leading" and "trailing" are terms used to
describe a location of certain components relative to other
components, it being understood that in other embodiments, the
orientation of such components may be reversed.
[0027] The leading and trailing braking system 52, 54 each include
a leading brake beam assembly 56 and a trailing brake beam assembly
58. Each of the leading and trailing brake beam assemblies 56, 58
on the leading and trailing braking assemblies 52, 54 include a
pair of brake heads 60 disposed at their respective outer ends. The
brake heads 60 each include one or more brake shoes 62 defining a
thickness and configured to contact an outer periphery of
respective wheels of the railway car trucks.
[0028] The braking system 50 is configured to generate friction
with the wheels of the respective railway car trucks to slow the
railway car. For the embodiment depicted, the leading and trailing
brake beam assemblies 56, 58 of the leading and trailing brake
assemblies 52, 54 are moved away from one another along the
longitudinal direction L in order to generate the desired friction
between brake shoes 62 and the respective wheels. More
particularly, the braking system 50 generally includes a brake
cylinder 64 configured to move the respective leading and trailing
brake beam assemblies 56, 58 away from one another along the
longitudinal direction L by transferring a force through a lever
assembly 66. The lever assembly 66 generally includes a plurality
of levers 68 and fixed length rods 70 to generate the desired
movement of the respective brake beam assemblies 56, 58 from the
brake cylinder 64. However, as the brake shoes 62 on the brake beam
assemblies 56, 58 and the wheels of the various trucks wear down
through use of the braking system 50, a thickness of the respective
brake shoes 62 and a diameter of the respective wheels may be
reduced. In order to accommodate these reductions, a slack adjuster
72 is provided. The slack adjuster 72 is configured to shorten in
length in order to compensate for the reduced thickness of the
brake shoes 62 and/or diameter of the wheels.
[0029] One having skill in the art will appreciate, however, that
in other exemplary embodiments, the braking system 50 may have any
other suitable configuration of leading or trailing brake
assemblies 52, 54, including the respective leading and trailing
brake beam assemblies 56, 58. Additionally, in other exemplary
embodiments, brake system 50 may utilize any other suitable means
for generating a braking force other than the brake cylinder 64,
and additionally, or alternatively, may utilize any other suitable
configuration of lever assembly 66 to transfer such braking force
to the leading and trailing brake assemblies 52, 54. Moreover, in
still other exemplary embodiments, the slack adjuster 72 may be
positioned elsewhere in the braking system 50, or may be configured
in any other suitable manner to compensate for the reduction in the
thickness of the brake shoes 62 and/or the diameter of the various
wheels.
[0030] Referring now to FIG. 2, a slack adjuster 100 in accordance
with an exemplary embodiment of the present disclosure is depicted.
The exemplary slack adjuster 100 depicted in FIG. 2 may be
configured in substantially the same manner as the slack adjuster
72 described above with reference to FIG.1, and accordingly may be
utilized in a braking system such as the exemplary braking system
50 also described above with reference to FIG. 1.
[0031] The slack adjuster 100 depicted defines an axial direction
A, a radial direction R, and a circumferential direction C, and
extends generally along the axial direction A between a first end
102 and a second end 104. The slack adjuster 100 includes a first
jaw 106 positioned at the first end 102 and a second jaw 108
positioned at the second end 104. A rod assembly 110 is attached to
the first jaw 106 and extends generally along the axial direction
A. Additionally, a tube 112 is attached to the second jaw 108 and
also extends generally along the axial direction A. The tube 112
encloses at least a portion of the rod assembly 110. As will be
discussed in greater detail below, a nut assembly 114 (see FIG. 5)
having at least a portion rotatably engaged with the rod assembly
110 is configured to transfer a force between the rod assembly 110
and the tube 112 and is also configured to allow the rod assembly
110 to extend or retract relative to the tube 112.
[0032] Referring now also to FIGS. 3 and 4, the slack adjuster 100
additionally includes a pawl box 116 attached to an outer surface
118 of the tube 112 over a pair of pawl openings 120 in the tube
112. More particularly, FIG. 3 provides a close-up perspective view
of the slack adjuster 100 of FIG. 2 prior to attachment of the pawl
box 116, and FIG. 4 provides a close-up perspective view of the
slack adjuster 100 of FIG. 2 after attachment of the pawl box
116.
[0033] As may be clearly seen in FIG. 3, the tube 112 defines a
pair of pawl openings 120 and at least one locator opening 122
positioned adjacent to the pawl openings 120. More particularly,
for the embodiment depicted, the tube 112 defines two locator
openings 122. The pawl openings 120 are positioned adjacent to the
nut assembly 114 of the slack adjuster 100 (see FIG. 5, below) and
are each configured to receive a pawl that restricts or allows
rotational movement of at least a portion of the nut assembly 114
relative to the tube 112. Moreover, the pawl box 116 includes a
main slot 124 configured to hold the one or more pawls in the pawl
openings 120 of the tube 112 when attached to the tube 112. The
pawl box 116 additionally includes a trigger slot 126. The trigger
slot 126 is configured to receive a trigger that selectively
engages or disengages one or both of the pawls to allow the slack
adjuster 100 to extend or retract as necessary.
[0034] Moreover, the pawl box 116 additionally includes at least
one locator tab 128 and at least two coupling projections 130. More
particularly, for the embodiment depicted, the pawl box 116 include
two locator tabs 128. When the pawl box 116 is attached to the tube
112, the locator tabs 128 of the pawl box 116 extend into the
locator openings 122 in the tube 112. It should be appreciated,
however, that in other exemplary embodiments, the tube 112 may
define any other suitable number of locator openings 122, and
similarly the pawl box 116 may include any other suitable number of
locator tabs 128. Additionally, or alternatively, the tube 112 may
not define any locator openings 122, and instead the at least one
locator tab 128 may be configured to extend into one or more of the
pawl openings 120.
[0035] Moreover, referring particularly to FIG. 4, for the
embodiment depicted, the pawl box 116 is attached to the tube 112
by forming the at least two coupling projections 130 of the pawl
box 116 around the outer surface 118 of the tube 112. For example,
the pawl box 116 may be attached to the tube 112 by placing the
tube 112 in a circular die, and pressing the pawl box 116 onto the
tube 112 such that the coupling projections 130 are
pressed/deformed by the circular die around the outer surface 118
of the tube 112 to hold the pawl box 116 in place. Such a
configuration may allow for a slack adjuster 100 capable of more
easily being assembled or manufactured. More particularly, with
such a configuration the pawl box 116 need not be welded to the
outer surface of the tube 112 of the slack adjuster 100,
[0036] Referring still to FIG. 4, and now also to FIG. 5, the nut
assembly 114 of the exemplary slack adjuster 100 of FIG. 2 will now
he described. As stated, FIG. 4 provides a close-up perspective
view of a center portion of the slack adjuster 100 of FIG. 2.
Additionally, FIG. 5 provides a side, cross-sectional view of the
center portion of the slack adjuster 100 of FIG. 2.
[0037] As may be more clearly seen in FIG. 5, the nut assembly 114
generally includes a nut 132 defining a threaded opening 134
rotatably engaged with a threaded portion 136 of the rod assembly
110. More particularly, for the embodiment depicted, the nut 132 is
threaded onto (or screwed onto) the threaded portion 136 of the rod
assembly 110. As will be understood, the nut 132 also includes a
geared outer surface 138 configured to be engaged by the pair of
pawls received in the pair of pawl openings 120 of the tube 112.
The not assembly 114 additionally includes a first bearing collar
140 and a second bearing collar 142. The first bearing collar 140
is sometimes referred to as a cone collar, and the second bearing
collar 142 is sometimes referred to simply as a bearing collar. The
first and second bearing collars 140, 142 are disposed on opposite
sides of the nut 132 along the axial direction A for constraining
the nut 132 along the axial direction A of the slack adjuster 100
relative to the tube 112.
[0038] A pair spring washers 144 are provided between the nut 132
and the first bearing collar 140 to bias the nut 132 away from the
first bearing collar 140 along the axial direction A. For the
embodiment depicted, the nut 132 includes a bearing 146 between the
nut 132 and spring washers 144 to allow for the nut 132 to more
easily rotate relative to the spring washers 144 and first bearing
collar 140. Additionally, the first bearing collar 140 includes a
tapered cone surface 148 corresponding in shape with a tapered
surface defined at an axial end 150 of the nut 132. When the nut
132 is pressed against the tapered cone surface 148 of the first
bearing collar 140 (after having overcome the bias of the spring
washers 144), the nut 132 may be fixed rotationally to the first
hearing collar 140. A bearing 152 is also provided between the
second bearing collar 142 at an opposite axial end 154 of the nut
132 to allow the nut 132 to more easily rotate relative to the
second bearing collar 142.
[0039] The first and second bearing collars 140, 142 are each
rigidly attached to the tube 112. During operation of the slack
adjuster 100, an axial force may be applied between the first and
second jaws 106, 108 of the slack adjuster 100. The nut assembly
114 is configured to transfer such a force between the rod assembly
110 (which receives the force from and/or transfers the force to
the first jaw 106) and the tube 112 assembly (which receives the
force from and/or transfers the force to the second jaw 108). More
particularly, for the exemplary slack adjuster 100 depicted, the
first bearing collar 140 is configured to transfer such force
between the rod assembly 110 and the tube 112. However, in other
embodiments, the second bearing collar 142 may additionally, or
alternatively, be configured to transfer such force. Accordingly,
the attachment between first and/or second bearing collars 140, 142
and the tube 112 must be capable of withstanding a potentially
large amount of force applied between the first and second jaws
106, 108 of the slack adjuster 100 along the axial direction A.
[0040] The inventors in the present application have found that
contrary to conventional wisdom, the nut assembly 114 may be
attached to the tube 112 by crimping, while still being capable of
withstanding the potentially large amount of force along the axial
direction A. Such an attachment method, the inventors found is
enabled at least in part due to the selection of materials and
design of the components, as discussed below.
[0041] For example, referring now also to FIG. 6, depicting a
close-up, perspective view of the first bearing collar 140 of the
nut assembly 114, the first bearing collar 140 defines a groove 156
in an outer surface 158 extending generally along the
circumferential direction C. At least a portion of the tube 112 is
crimped into the groove 156 of the first hearing collar 140,
rigidly attaching the tube 112 to the first bearing collar 140.
Moreover, the first bearing collar 140 defines a center opening 160
through which a portion the rod assembly 110 extends (FIG. 5). The
exemplary first bearing collar 140 depicted is a solid component
between the center opening 160 and the groove 156 free from any
openings or holes.
[0042] Additionally, for the embodiment depicted, the first bearing
collar 140 of the nut assembly 114 may be formed of a steel
material having a tensile strength of at least about seventy-five
(75) kilopounds per square inch ("ksi") and a yield strength of at
least about sixty (60) ksi. More particularly, the first bearing
collar 140 may have a tensile strength of at least about eighty
(80) ksi and a yield strength of at least about sixty-five (65)
ksi, or may have a tensile strength of at least about eighty-five
(85) ksi and a yield strength of at least about seventy (70) ksi.
For example, the first hearing collar 140 may he formed of a
Chinese No. 45 steel. Moreover, the tube 112 may also be formed of
a steel material having a tensile strength of at least about
seventy (70) ksi and a yield strength of at least about sixty (60)
ksi. More particularly, the tube 112 may have a tensile strength of
at least about seventy-five (75) ksi and a yield strength of at
least about sixty-five (65) ksi, or may have a tensile strength of
at least about eighty (80) ksi and a yield strength of at least
about seventy (70) ksi. For example, the tube 112 may be formed of
a 1026 carbon steel, conforming to the American Society for Testing
and Materials ("ASTM") A513 Type 5 Drawn Over Mandrel.
[0043] It should be appreciated, that as used herein, terms of
approximation, such as "about" or "approximately," refer to being
within a ten percent (10%) margin of error.
[0044] Notably, prior configurations have attached the first
bearing collar 140 to the tube 112 by having a plurality of holes
extending along the radial direction R between the center opening
160 and the outer surface 158 of the first bearing collar 140
corresponding to similar openings in the tube 112. The holes in the
first bearing collar 140 in prior configurations were threaded such
that bolts may be used to attach the first bearing collar 140 to
the tube 112. Such a configuration required each hole to he
precisely drilled and tapped. Additionally, such a configuration
required an increased thickness of the tube 112 and first bearing
collar 140 such that the tube 112 and first bearing collar 140
could withstand the necessary forces along the axial direction A
despite the holes drilled therethrough. By contrast, however, with
the present configuration no such holes need to be drilled and/or
threaded in order to attach the tube 112 and first bearing collar
140. Accordingly, the present configuration may provide for a much
more efficient and less time-consuming process for manufacturing
and attaching the first bearing collar 140 to the tube 112.
Additionally, the tube 112 may define a lesser thickness, such that
a weight of the tube 112 and slack adjuster 100 are decreased with
the present configuration.
[0045] Similarly, referring still to FIG. 5 and now also to FIG. 7,
depicting a close-up, perspective view of the second bearing collar
142 of the nut assembly 114, the second bearing collar 142 also
defines a groove 162 in an outer surface 164 extending generally
along the circumferential direction C. At least a portion of the
tube 112 is crimped into the groove 162 and the second bearing
collar 142, attaching the tube 112 to the second bearing collar
142. The second bearing collar 142 also defines a center opening
166 through which a portion of the rod assembly 110 extends. The
second bearing collar 142 is also a solid component between the
center opening 166 and the groove 162 defined in its outer surface
164, free from any openings or holes, and may be formed of the same
material as the first bearing collar 140 discussed above.
Accordingly, the present configuration may also provide for a much
more efficient and less time-consuming process for attaching the
second bearing collar 142 to the tube 112 and for manufacturing the
slack adjuster 100, as well as the other benefits discussed
above.
[0046] Referring now to FIGS. 8 and 9, a perspective view and side
cross-sectional view of the second end 104 of the slack adjuster
100 are provided. Similar to the first and second bearing collars
140, 142, the second jaw 108 of the exemplary slack adjuster 100
depicted is attached to the tube 112 by crimping. More
particularly, the second jaw 108 includes a substantially smooth
cylindrical base 168 defining a groove 170 in an outer surface 172
extending generally along the circumferential direction C. At least
a portion of the tube 112 is crimped into the groove 170 in the
base 168 of the second jaw 108, attaching the tube 112 to the base
168 of the second jaw 108. For the exemplary embodiment depicted,
the groove 170 in the base 168 of the second jaw 108 also defines a
width W.sub.G along the axial direction A and a depth D.sub.G along
the radial direction R. In certain exemplary embodiments, the width
W.sub.G of the groove 170 in the base 168 the second jaw 108 may be
at least about 0.40 inches wide, at least about 0.50 inches wide,
or at least about 0.75 inches wide. Additionally, in certain
exemplary embodiments, the depth D.sub.G of the groove 170 in the
base 168 of the second jaw 108 may be at least about 0.10 inches
deep, at least about 0.15 inches deep, or at least about 0.20
inches deep.
[0047] Moreover, as shown most clearly in FIG. 9, the second jaw
108 includes a flange 174 having a width W.sub.F along the axial
direction A. For the embodiment depicted, the flange 174 has a
width W.sub.F along the axial direction A of at least about 0.15
inches. Additionally, the second jaw 108 may be formed of a steel
material having a tensile strength of at least about eighty (80)
ksi and a yield strength of at least about seventy (70) ksi. More
particularly, the second jaw 108 may have a tensile strength of at
least eighty-five (85) ksi and a yield strength of at least about
sixty-five (75) ksi, or may have a tensile strength of at least
about ninety (90) ksi and a yield strength of at least about eighty
(80) ksi. For example, the second jaw 108 may be formed of 1035
steel.
[0048] It should be appreciated, however, that the dimensions
provided above are by way of example only, and that in other
exemplary embodiments, the flange 174 may have any other suitable
width W.sub.F, the groove 170 in the base 168 of the second jaw 108
may have any other suitable width W.sub.G, and the groove 170 in
the base 168 of the second jaw 108 may also have any other suitable
depth D.sub.G. For example, in other exemplary embodiments, the
flange 174 may be at least about 0.20 inches wide, at least about
0.25 inches wide, or at least about 0.30 inches wide. Additionally,
or alternatively, in other exemplary embodiments, the groove 170 in
the base 168 may be an overly wide groove, defining a width W.sub.G
greater than or equal to about three inches, greater than or equal
to about five inches, or greater than or equal to about seven
inches. Further, in still other exemplary embodiments, the groove
170 in the base 168 may actually be a plurality of circumferential
grooves spaced along the base 168 of the second jaw 108. Such a
configuration may provide additional strength to the connection
between the second jaw 108 and the tube 112.
[0049] Notably, the inventors have unexpectedly found that the
slack adjuster 100 can withstand a relatively large force along the
axial direction A with the first bearing collar 140 and the second
jaw 108 attached to the tube 112 by crimping. More particularly,
the inventors have unexpectedly found that a slack adjuster 100 in
accordance with the following exemplary embodiment can withstand a
relatively large force along the axial direction A with the first
bearing collar 140 and the second jaw 108 attached to the tube 112
by crimping: (a) when the tube 112 is formed of a material having a
tensile strength of at least about eighty (80) ksi and a yield
strength of at least about seventy (70) ksi; (b) when the first
bearing collar 140 is formed of a material having a tensile
strength of at least about eighty-five (85) ksi and a yield
strength of at least about seventy (70) ksi; (c) when the second
jaw 108 is formed of a material having a tensile strength of at
least about ninety (90) ksi and a yield strength of at least about
eighty (80) ksi; (d) when the second jaw 108 includes a flange 174
having a width W.sub.F along the axial direction of at least about
0.15 inches; and (e) when the second jaw 108 defines a groove 170
in the base 168 having a width W.sub.G of at least about 0.50
inches and a depth D.sub.G of at least about 0.15 inches. With such
an exemplary embodiment, the inventors have unexpectedly found that
the exemplary slack adjuster 100 may be capable of withstanding at
least about 60,000 pounds of force along the axial direction A.
Such a configuration may therefore withstand the typical forces
incurred during operation of a braking system, plus an additional
safety factor.
[0050] Referring particularly to FIG. 9, the base 168 of the second
jaw 108 defines a central opening 176 extending generally along the
axial direction A through at least a portion of the base 168 of the
second jaw 108. The base 168 of the second jaw 108 is a solid
component between the central opening 176 and the groove 170, free
from any openings or holes. It should be appreciated, however, that
in other exemplary embodiments, the base 168 may not include an
opening 176. Accordingly, the present configuration may also
provide for a much more efficient and less time-consuming process
for attaching the base 168 of the second jaw 108 to the tube 112
and for manufacturing the slack adjuster 100, as well as the other
benefits discussed above.
[0051] Referring now to FIG. 10, a close-up view is provided of a
groove 178 defined in an outer surface 180 of a component 182 and a
crimp die 184. The crimp die 184 is configured to move generally
along the radial direction R and press/deform a portion of the tube
112 (original shape of tube 112 shown as numeral 112' in phantom)
into the groove 178 defined in the outer surface 180 of the
component 182. The crimp die 184 defines a width W.sub.CD along the
axial direction A. The width W.sub.CD of the crimp die 184 is
chosen such that once the portion of the tube 112 is
pressed/deformed into the groove 178 defined in the outer surface
180 the component 182, such portion of the tube 112 conforms to the
shape of the groove 178. For example, the width W.sub.CD of the
crimp die 184 may be approximately equal to a width W.sub.G, of the
groove 178 minus twice a thickness T.sub.T of the tube 112. Such a
configuration may provide an attachment point capable of
withstanding the axial forces required by the slack adjuster
100.
[0052] The exemplary groove depicted defines a pair of inner edges
186 and a pair of top ledges 188 (along the axial direction A).
Additionally, the crimp die 184 defines a crimping portion 190
defining a pair of crimping edges 192. For the exemplary embodiment
depicted, each of the inner edges 186, the top ledges 188, and the
crimping edges 192 define a radius, or a radius of curvature
R.sub.C, greater than zero. More particularly, for the embodiment
depicted, each of the inner edges 186, the top ledges 188, and the
crimping edges 192 define a radius R.sub.C greater than or equal to
about 1/8th of an inch (0.125 inches). However, in other exemplary
embodiments, one or more of the inner edges 186, the top ledges
188, and the crimping edges 192 may define a radius R.sub.C greater
than or equal to about 1/10th of an inch (0.10 inches), greater
than or equal to about 1/6th of an inch (0.16 inches), or greater
than or equal to about 1/4th of an inch (0.25 inches). Moreover, it
should be appreciated, that in still other exemplary embodiments,
one or more of the inner edges 186, the top ledges 188, and the
crimping edges 192 may define any other suitable radius R.sub.C, or
may define a radius R.sub.C equal to zero (i.e., a ninety degree
edge). As used herein, the term "radius" or "radius of curvature"
and is the radius of the circle that touches a curve at a given
point and has the same tangent and curvature at that point.
[0053] Furthermore, it should be appreciated, that the exemplary
groove 178 defined in the outer surface 180 of the component 182
depicted in FIG. 10 may represent one or more of the groove 156
defined in the outer surface 158 of the first bearing collar 140,
the groove 162 defined in the outer surface 164 of the second
bearing collar 142, and/or the groove 170 defined in the outer
surface 172 of the base 168 of the second jaw 108. Further, in
certain exemplary embodiments, one or more other portions of the
exemplary slack adjuster 100 may be attached using a similar
crimping method. For example, referring back briefly to FIG. 2, the
exemplary slack adjuster 100 additionally includes an end cap 194
defining a groove 196 extending generally along the circumferential
direction C in an outer surface with at least a portion of the tube
112 crimped therein, attaching the tube 112 to the end cap 194. As
will be appreciated, at least a portion of the rod assembly 110
slidably extends through an opening in the end cap 194 (not shown),
and the end cap 194 does not support an axial force applied between
the first and second jaws 106, 108.
[0054] Referring now to FIG. 11, a flow diagram is provided of an
exemplary method (200) for manufacturing a slack adjuster for
railroad car braking system in accordance with an exemplary aspect
of the present disclosure. In certain exemplary aspects, the
exemplary method (200) may be used to manufacture the exemplary
slack adjuster depicted in FIG. 2 and described above.
[0055] As indicated, the exemplary method (200) generally includes
at (202) attaching a first jaw to a rod assembly and at (204)
positioning a nut assembly over a threaded portion of the rod
assembly. Moreover, the exemplary method (200) includes at (206)
attaching the nut assembly to a tube extending generally along the
axial direction, such that at least a portion of the nut assembly
is fixed along the axial direction relative to the tube. Although
not depicted, in certain exemplary aspects, attaching the nut
assembly to the tube at (206) may include crimping a portion of the
tube into a groove defined in an outer surface of a first bearing
collar and/or crimping a portion of the tube into a groove defined
in an outer surface of a second bearing collar.
[0056] Referring still to FIG. 11, the exemplary method (200)
includes at (208) attaching the tube to a base of a second jaw by
crimping a portion of the tube into a groove defined in the base of
the second jaw, fixing the base of the second jaw to the tube. In
certain exemplary aspects, attaching the tube to a base of the
second jaw by crimping a portion of the tube into the groove
defined in the base of the second jaw at (208) includes crimping a
portion of the tube into the groove defined in the base of the
second jaw using a plurality of crimp dies. Each of the plurality
of crimp dies includes a crimping portion, and in certain exemplary
aspects, each of the crimping portions may define a crimping edge
having a radius of at least about 1/8th of an inch. However, in
other exemplary aspects, the crimping edges of the crimping
portions may define any other suitable radius, or no radius at
all.
[0057] Moreover, for the exemplary method (200) depicted in FIG.
11, the method (200) further includes attaching a pawl box to the
tube at (210). Attaching the pawl box to the tube at (210) may
include positioning the pawl box over a pair of pawl openings
defined in the tube such that at least one locator tab of the pawl
box extends into at least one locator opening defined in the tube.
Additionally, attaching the pawl box to the tube at (210) may also
include forming a pair of coupling projections around an outer
surface of the tube.
[0058] As is also depicted, for the exemplary method (200) depicted
in FIG. 11, the exemplary method (200) also includes reconditioning
the slack adjuster at (212). Reconditioning the slack adjuster at
(212) may take place, e.g., after extended use of the slack
adjuster wherein repairs may be necessary. For example,
reconditioning the slack adjuster at (212) may take place after ten
years or more of use of the slack adjuster. Alternatively,
reconditioning the slack adjuster at (212) may take place during an
initial manufacturing of the slack adjuster in order to readjust or
correct a mistake made during such manufacturing process.
Regardless, reconditioning the slack adjuster at (212) may include
removing the second jaw from the tube by shearing off the portion
of the tube crimped into the groove in the base of the second jaw
with a plurality of crimp dies. Moreover, in other exemplary
aspects, reconditioning the slack adjuster at (212) may
additionally or alternatively include removing one or more portions
of the nut assembly by shearing off the portion of the tube crimped
into the groove in the first bearing collar and/or the portion of
the tube crimped into the groove in the second bearing collar. The
crimp dies used for shearing off such portions of the tube may
define a width along the axial direction of the slack adjuster
approximately equal to or slightly less than a width of the
respective groove. However, in other exemplary aspects,
reconditioning the slack adjuster at (212) may alternatively
include removing the portion of the tube crimped into the groove in
the base of the second jaw and/or a groove in one or more portions
of the nut assembly by using a tube cutter, machining such portion
off, or using any other suitable method.
[0059] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. For example, in other embodiments, elements of the
exemplary methods described herein may be performed in any suitable
order. Such other examples are intended to be within the scope of
the claims if they include structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal language of the claims.
* * * * *