Brake actuator and method of manufacture

A method and apparatus is disclosed for securely attaching existing central aluminum or steel adaptors for air brake actuators to existing steel service brake housings, existing steel emergency brake housings, or both without major modification to either housing or the adaptor. An annular shoulder with an elongated annular flange above it is provided in the steel brake housing, and the aluminum adaptor is provided with a small outwardly extending annular lip. A flexible diaphragm is first placed directly on the shoulder of the steel brake housing. The aluminum or steel adaptor is then placed on top of the diaphragm such that the annular lip of the adaptor fits inside the annular flange of the housing. A slightly deformable annular steel piece is then placed around the aluminum adaptor so that it comes to rest against the annular lip while also touching the annular steel flange of the housing. One or more breaks may be provided in the annular steel piece to facilitate placing it over the aluminum adaptor. A weld is then applied to connect the annular steel piece to the annular flange, thereby holding the aluminum or steel adaptor and diaphragm securely in place.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to spring brake actuators used on commercial 
trucks, and more particularly to an apparatus and method for attaching 
either the outer spring brake housing, the outer service brake housing, or 
both, of a spring brake actuator to a central adaptor made of the same or 
a dissimilar metal. 
2. Description of the Prior Art 
Various forms of pneumatic vehicle spring brake actuators have been 
introduced over the years primarily for use in the trucking industry. A 
typical actuator includes a service brake portion which is used for 
slowing or stopping a vehicle, and may also include an emergency or 
parking brake portion. The service brake portion is characterized by a 
closed housing which contains a movable diaphragm stretched across the 
inside. One side of the diaphragm is connected to a centrally located 
slidable push rod which extends out of the housing for attachment to the 
brakes of the vehicle. On the other side of the diaphragm a sealed chamber 
is formed within the housing. 
An opening is provided in the sealed chamber for connection to a pneumatic 
(air) pressure source usually provided by an on-board air compressor. The 
brakes of the vehicle can be applied by introducing sufficient pneumatic 
pressure into the sealed chamber to act against the service brake 
diaphragm which moves the push rod out. A small return spring is provided 
inside the housing around the push rod to urge it to retract when the air 
pressure behind the diaphragm is reduced. 
When employed, a typical emergency brake portion is attached directly 
behind or made a part of the service brake assembly. The emergency brake 
is a separate closed housing which contains a heavy compression spring and 
a second movable diaphragm in sealed contact with a slidable central rod 
which communicates directly with the push rod of the service brake. 
A second sealed chamber is formed inside the emergency brake housing on one 
side of the diaphragm, and the heavy compression spring is deployed on the 
opposite side. As with the service brake, the sealed chamber of the 
emergency brake is connected to the on-board pneumatic source of the 
vehicle. As long as sufficient air pressure is provided, the diaphragm in 
the emergency brake will remain fully extended thereby compressing the 
large spring. However, should pressure fall, or should there be a leak in 
the sealed chamber, the diaphragm will be unable to hold the large 
compression spring in place. When this occurs, either slowly or quickly, 
the large compression spring will cause the push rod to extend out thereby 
applying the brakes of the vehicle. 
Under normal conditions, when the vehicle is parked, the air pressure to 
the emergency brake portion is cut off causing the large compression 
spring to apply the brakes. 
Because the spring brake assembly is a critical safety system, it has to be 
designed and manufactured for exceptional reliability. Moreover, because 
the compression spring inside the spring actuator must exert a sufficient 
force to apply a maximum braking force to the vehicle independent of any 
external air pressure assistance from the service brake system, the spring 
in its compressed state stores sufficient kinetic energy to be lethal if 
the spring brake housing is opened without first taking adequate 
precautions to secure the spring in its compressed state or to release the 
stored energy in a controlled manner. 
It is conventional to fabricate the spring brake housing containing the 
compression spring and diaphragm in two opposing sections (an aluminum 
adaptor housing, and a steel cap or cup) separated by the periphery of the 
diaphragm, with the two opposing sections being clamped together with 
sufficient force to maintain an air-tight seal between the diaphragm and 
the housing. Since unauthorized opening of the housing is potentially 
dangerous to the inexperienced mechanic, and since unauthorized re-sealing 
using defective seals or improper procedures could result in a poor 
diaphragm seal or other internal defect, it is also conventional to 
discourage unauthorized access, disassembly, and reassembly of the housing 
by appending a warning label to the housing and using a clamping means 
which is temper-resistant or at least tamper-evident, so that a new 
clamping means, not readily available to unauthorized personnel, is 
required before the housing can be reassembled. 
Because of the danger presented by the compression of the large spring of 
these brake systems, numerous inventions have been patented which provide 
different ways of improving safety. Many of these inventions are directed 
towards securing the assembly of the two halves of the housing between 
which the diaphragm is deployed. 
A typical service brake actuator housing is made of two steel cups which 
form the two halves. When combined with an emergency brake actuator, the 
housing has three distinct parts: a lower cup which forms the bottom of 
the service brake actuator, an upper cup which forms the top of the 
emergency brake actuator, and an hourglass-shaped central body or adaptor 
which is provided between them. The adaptor makes up the top half of the 
service brake housing, and the bottom half of the emergency brake housing. 
Normal positioning of the two brake diaphragms results in the adaptor 
being part of the sealed chambers of both the service brake and the 
emergency brake. As a result, it is common for the adaptor to include the 
openings into each chamber for attachment to the pneumatic pressure source 
for the brakes. 
The below-listed United States and foreign patents are known to exist: 
______________________________________ 
No. Patent No. 
Date Inventor 
______________________________________ 
1 2,541,205 February 13, 1951 
Christophersen 
2 3,101,133 August 20, 1963 
House 
3 7308049.6 1973 Bosch (German) 
4 028074 June 27, 1978 Girling (G.B.) 
5 4,850,263 July 25, 1989 Rumsey 
6 4,960,036 October 2, 1990 
Gummer 
7 5,062,455 November 5, 1991 
Schurter 
8 5,067,391 November 26, 1991 
Choinski 
9 5,193,432 March 16, 1993 
Smith 
10 5,205,205 April 27, 1993 
Choinski 
11 5,285,716 February 15, 1994 
Thompson 
12 5,315,918 May 31, 1994 Pierce 
13 5,353,688 October 11, 1994 
Pierce 
______________________________________ 
These patents disclose different methods and apparatus for attachment of 
the two halves or cups of a brake housing. Annular clamps are taught in 
U.S. Pat. Nos. 2,541,205 to Christophersen; 4,960,036 to Gummer, et al; 
and 5,193,432 to Smith. Such clamps are bulky and cumbersome in that the 
flanges, nuts and bolts used for connection may not easily fit into the 
cramped brake area of a vehicle. 
Various ways of crimping or bending the edge flanges of the two housing 
cups are taught in U.S. Pat. No. 3,101,133 to House; a German Patent 
Application No. G 73 08 049.6 filed by Bosch; and U.S. Pat. No. 4,850,263 
to Rumsey. The Rumsey patent utilizes overlapping lips where one is 
spinned over the other and bent into position by use of the lathe or other 
suitable machine. Each of these devices is limited to the use of a strong 
bendable metal such as steel. 
The three U.S. Pat. Nos. to Gummer and Choinski (Nos. 4,960,036; 5,067,391; 
and 5,205,205) each disclose use of a clamp ring, use of a metal spun 
annular crimp of a flange on one of the housing cups, and the use of a 
separate circular channel clamp for attachment of the housing cups. Clamp 
rings are bulky and dangerous as noted above; and, although the circular 
channel clamp is a more permanent structure, it, as well as the metal spun 
flanges, are again limited to use with steel. 
The use of a snap ring for attachment is shown in U.S. Pat. No. 5,353,688 
to Pierce, et al, and in U.K. Patent No. GB 2,000,225A to Girling Midland, 
etc. U.S. Pat. No. 5,315,918 to Pierce discloses several methods of 
attachment including bayonet, screw thread, slots plus pins, and welds. 
Each of these methods of attachment requires that the cup and/or adaptor 
be uniquely modified in order to hold or accept such things as the snap 
ring, the pins, the screw threads, the slots, etc. Such adaptations render 
the cup and adaptor parts unusable except with correspondingly adapted 
parts, thereby severely limiting overall use, especially for repair and 
reuse. 
The welding together of two halves of like material is shown in U.S. Pat. 
No. 5,062,455 to Schurter and U.S. Pat. No. 5,285,716 to Thompson. 
It is desirable to be able to use central adaptor parts in brake actuators 
that are cast from aluminum as opposed to die pressed from steel sheets. 
However, attaching such dissimilar metals together has heretofore only 
been accomplished by use of annular clamps or the like. The ears, nuts and 
bolts of such clamps create significant clearance problems in the close 
tolerances of the brake area of a vehicle, making such methods of 
attachment unattractive. 
Because of its hourglass shape, making an adaptor from steel requires the 
welding together of two halves. There is great expense involved in 
creating the necessary tooling to make these two halves, and then 
attaching them together. However, the price of aluminum can make it an 
attractive alternative to steel as a material to make the adaptor from. 
It is also desirable for a brake manufacturer or remanufacturer to be able 
to use its conventional existing aluminum molds, or its existing steel 
tooling for that matter, to create adaptor pieces that may be more 
securely attached to the housing cups. Thus, it is equally desirable to 
have a secure attachment device that does not require retooling of the 
parts that are to be attached together. 
Casting the adaptor pieces from aluminum is also desirable in that, 
compared to steel, many different molds may be easily and cheaply created 
for the various sized pieces. 
In order to avoid increasing labor and service costs, it is common for a 
brake actuator having a single worn out component (e.g. a diaphragm) to 
simply be replaced in its entirety by another brake actuator, as opposed 
to repairing the actuator or replacing the worn out part in the field. 
When this occurs, the remaining parts of the old brake actuator, 
particularly the housing cups and adaptor, should be reusable for 
remanufacturing. It is therefore desirable to have a secure attachment 
method and device for the adaptor and housing cups that gives the brake 
actuator a long useful life, yet allows the adaptor and housing cups to be 
disassembled without significant damage in order that they may be reused 
or remanufactured into brake actuators with correspondingly long useful 
lives. 
The problem presented in using aluminum adaptors in spring brake assemblies 
is securely attaching them to their steel counterparts. The present 
invention provides such a method and apparatus, while at the same time 
accomplishing many of the desirable conditions described above. 
SUMMARY OF THE INVENTION 
The present invention provides both a method and apparatus, as well as 
several alternatives, for securely attaching existing conventional central 
aluminum or steel adaptors for air brake actuators to existing steel 
service brake housings, existing steel emergency brake housings, or both 
without major modification to either housing or the adaptor. The open ends 
of the steel service brake or emergency brake housings require an annular 
shoulder with an elongated annular flange above it, which is a minor 
change from existing housings. The open ends of the aluminum adaptor 
require a small outwardly extending annular lip, which many currently 
have. The outside diameter of the annular lip must be smaller than the 
inside diameter of the annular flanges. 
A flexible diaphragm is first placed directly on the shoulder of the 
selected steel housing. The aluminum adaptor is then placed on top of the 
diaphragm such that the annular lip of the adaptor fits inside the annular 
flange of the housing. It is not possible to securely weld such dissimilar 
metals together; however, it is possible to weld steel to steel. 
Accordingly, at least one slightly deformable annular steel piece is also 
provided. The piece may have a single break therein, or multiple breaks 
resulting in multiple pieces. The piece (or pieces) is placed around the 
aluminum adaptor so that it comes to rest against the annular aluminum lip 
while also touching the annular steel flange of the housing. The one or 
more breaks in the piece are necessary to allow it to be opened 
sufficiently to fit around the aluminum adaptor. To the extent that the 
diameters of the two ends of the adaptor are different, the annular piece 
for use on the larger diameter end may be continuous (having no break 
therein) since it will fit over the smaller diameter end. A weld is then 
applied to connect the annular steel piece(s) to the annular flange, 
thereby holding the aluminum or steel adaptor and diaphragm securely in 
place. The weld may be continuous or in parts around the diameter. 
Since it is important to obtain a secure seal around the diaphragm, the 
outside edge of the diaphragm may be slightly thicker than its remaining 
cross section. Substantial force exceeding 1000 pounds is applied to the 
adaptor and housing as they are welded together using the annular steel 
piece. This force compresses and deforms the outside edge of the diaphragm 
causing an airtight seal. The weld is applied to the housing shoulder 
flange as remote as possible from the diaphragm in order to avoid damaging 
or melting it. The shoulder of the housing may be placed in a heat sink 
during the welding process to help prevent damage to the diaphragm. 
However, the heat sink may not be necessary depending upon the material 
used to make the diaphragm. 
The preferred embodiment of the present invention generally will not 
require any bulky clamps, or any special modifications to the aluminum 
adaptor. It provides a strong and secure attachment between the adaptor 
and housing, and an airtight seal for the diaphragm. The welded annular 
steel piece may be later removed without damage to the aluminum or steel 
adaptor allowing the adaptor to be reused with another brake housing. 
It is therefore a primary object of the present invention to provide a 
method and apparatus for securely attaching a central aluminum or steel 
adaptor piece to either a steel service brake or steel emergency brake 
housing of an air brake actuator. 
It is also a primary object of the present invention to provide a method 
and apparatus for assuring a tight seal of the diaphragm between the 
aluminum or steel adaptor piece and either the service brake or emergency 
brake housing of an air brake actuator. 
It is a further important object of the present invention to provide a 
method and apparatus for securely attaching an aluminum or steel adaptor 
piece to a selected steel brake housing by use of an annular steel piece 
that is fitted over said adaptor and welded to said housing. 
It is a further important object of the present invention to provide a 
method and apparatus for reusing an aluminum or steel adaptor piece that 
is held in place by the welding onto the steel brake housing of an annular 
steel piece such that when said welded steel piece is removed said adaptor 
piece is preserved for reuse. 
It is a further important object of the present invention to provide a 
method and apparatus for securely attaching an aluminum or steel adaptor 
piece to a selected steel brake housing by use of an annular steel piece 
that is fitted over said adaptor and welded to said housing such that when 
said welded steel piece is removed said adaptor piece and or said housing 
is preserved for reuse. 
It is a further important object of the present invention to provide a 
method and apparatus for securely attaching an aluminum or steel adaptor 
piece to a selected steel brake housing without cumbersome and space 
consuming annular clamps having ears, nuts or bolts. 
It is a further important object of the present invention to provide a 
method and apparatus for securely attaching an aluminum or steel adaptor 
piece to a selected steel brake housing that does not require any major 
modification of the tooling necessary to create the adaptor or housing. 
It is a further object of the present invention to provide a variety of 
different annular steel pieces each having at least one break therein for 
use in securely attaching an aluminum or steel adaptor piece to a selected 
steel brake housing of an air brake actuator. 
It is a further object of the present invention to provide a method and 
apparatus for securely attaching a central aluminum or steel adaptor piece 
to either a steel service brake or steel emergency brake housing of an air 
brake actuator utilizing an annular formed steel piece held in place using 
rivets, screws or pins. 
It is a further object of the present invention to provide a method and 
apparatus for securely attaching a central aluminum or steel adaptor piece 
to either a steel service brake or steel emergency brake housing of an air 
brake actuator utilizing an annular clamp made of formed steel and a weld. 
It is a further object of the present invention to provide a method and 
apparatus for securely attaching a central aluminum or steel adaptor piece 
to either a steel service brake or steel emergency brake housing of an air 
brake actuator utilizing an annular steel piece and a set of notched tangs 
which correspond to openings in the housing cap. 
It is a further object of the present invention to provide a method and 
apparatus for securely attaching a central aluminum or steel adaptor piece 
to either a steel service brake or steel emergency brake housing of an air 
brake actuator utilizing a layer of lamanate carbon fiber. 
It is a further object of the present invention to provide a method and 
apparatus for securely attaching a central aluminum or steel adaptor piece 
to either a steel service brake or steel emergency brake housing of an air 
brake actuator utilizing an L-shaped annular steel piece co-molded with 
the cast aluminum adaptor piece and welded to the housing. 
It is a further object of the present invention to provide a method and 
apparatus for securely attaching a central aluminum or steel adaptor piece 
to either a steel service brake or steel emergency brake housing of an air 
brake actuator utilizing a set of discontinuous clips made of formed steel 
and welds. 
Additional objects of the invention will be apparent from the detailed 
descriptions and the claims herein.

DETAILED DESCRIPTION OF THE DRAWINGS 
Referring to the drawings wherein like reference characters designate like 
or corresponding parts throughout the several views, and referring 
particularly to FIGS. 1, 2, 2A and 7 it is seen that the invention 
includes an air brake actuator, generally 30, including a service brake 
housing 31, an emergency brake housing 32, and a central cylindrical 
adaptor base 35 between the service brake and emergency brake housings. A 
slidable push rod 25 extends outward from the service brake housing for 
connection to the brakes of the vehicle. Openings 24 are provided in the 
adaptor for connection to the pneumatic pressure source. 
Referring to FIG. 1 and the detail of FIG. 7, it is seen that emergency 
spring brake housing 32 includes an annular shoulder 33 and an annular 
axially-extending flange 34, and that adaptor 35 includes an outwardly 
extending lip 36. A flexible diaphragm 40 is also provided which may have 
a thickened outer circumferential edge 41. An annular steel retaining 
piece 45 which may have one or more openings 46 therein (see FIGS. 21, 21A 
and 21B) is provided between the upper flange 34 of housing 32 and adaptor 
35, just above lip 36. Piece 45 is welded to the top of flange 34 at 49. 
This same configuration may also be used to attach the service brake 
housing 31 to the opposite end of the adaptor 35. 
An exploded view of a combination service brake and emergency brake 
actuator, including the sub-assembly parts, is shown in FIG. 2. These 
include the main compression spring 27, an intermediate push rod 28, 
return springs 29, and push rod 25 with plate, and disc 23. 
FIGS. 3, 4, 7, 8, 9, 13 and 17 show different embodiments of the broken 
annular piece 45. In FIG. 3, as in FIG. 7, piece 45 is an annular ring 
having a round cross section. A second annular lip 37 is provided on 
aluminum adaptor 35 in the embodiment of FIG. 3 for securely holding piece 
45 in place. FIG. 4 shows a molded annular steel piece 45 having a cross 
section in the shape of a modified "Z" where one end slides snugly over 
flange 34, and the other end conforms with lip 36 on adaptor 35. A 
resistance spot weld is made where piece 45 fits over the top of axially 
extending flange 34. FIG. 8 shows piece 45 having a semi-circular cross 
section so that a flat area is adjacent to flange 34, and weld 49 is made 
at the top of flange 34. FIG. 9 shows a molded annular piece 45 having a 
cross section in the shape of a modified "V" with a flat outside adjacent 
to flange 34, and a rounded inside conforming with the shape of lip 36 on 
adaptor 35. FIG. 13 shows annular piece 45 having a rectangular cross 
section with one flat side adjacent to flange 34. FIG. 17 shows piece 45 
as a taller rectangle with more surface area touching flange 34 while the 
bottom of rectangle 45 holds lip 36 in place. 
FIGS. 5 and 10 show a molded annular steel piece 45 which is attached to 
flange 34 using a rivet, pin or screw 51. In FIG. 10, piece 45 has a cross 
section in the shape of a modified "Z" where one end slides snugly over 
flange 34, and the other end conforms with lip 36 on adaptor 35. 
In FIGS. 6, 15 and 19 piece 45 is in the form of an annular C-shaped clamp 
made of formed steel. It is to be noted that in these three embodiments, 
housing 32 has no annular flange 34, and diaphragm 40 is sandwiched 
between housing 32 and adaptor 35 and held in place by clamp piece 45. 
However, instead of being spin molded or deformed for attachment, as shown 
in FIG. 6, piece 45 is welded along the bottom edge at 49. A set of 
discontinuous C-shaped clips 47 may be used instead of a single piece 45 
as shown in FIG. 19 and 19A. Alternatively, the bottom of piece 45 may be 
exaggerated, as shown in FIG. 15, so that no weld is required for 
attachment. 
FIGS. 11 & 12 show two related embodiments utilizing a set of tangs instead 
of a weld. FIG. 11 shows the modified "Z" shaped piece 45 of FIGS. 4 and 
10 in which a set of protruding tangs 52 are provided which fit into a set 
of corresponding notches 38 in flange 34. In FIG. 12, a set of protruding 
tangs 53 are die punched into flange 34 whereby lip 36 of adaptor 35 is 
snapped into place. 
In FIG. 14, lamanate carbon fiber 55 is molded into an annular ring around 
flange 34 and the lower leg and lip 36 of adapter 35. 
In FIGS. 16 and 18, the cross section of piece 45 has an L-shape, and lips 
36 and 37 of adapter 35 define a pronounced opening into which the 
horizontal lower end of L-shaped piece 45 fits. The vertical end of piece 
45 is adjacent to flange 34 allowing for weld 49 at the top. In the 
embodiment of FIG. 16, the L-shaped piece is co-molded with the aluminum 
adaptor. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In the preferred embodiment, the cylindrical adaptor base of the present 
invention is made of aluminum and cast in an appropriate mold. However, 
the present invention works equally well with any metal adaptor. Tooling 
for an aluminum adaptor is far less expensive than forming the same part 
from a steel sheet. Openings for attachment of each chamber to the 
pneumatic source are provided in the adaptor. An outside annular lip is 
provided at each end of the adaptor. The housing cups of both the service 
brake and emergency brake are made of steel. The open ends of each housing 
cup include an annular shoulder adjacent to an axially extending annular 
flange. The inside diameters of the annular flanges should be slightly 
larger than the outside diameters of the annular lips on the corresponding 
ends of the adaptor so that said lips fit snugly into said flanges. Each 
annular steel piece 45 should have a diameter that is approximately the 
same as the corresponding annular lip (on either emergency brake end or 
service brake end) of the adaptor. Each piece 45 may require at least one 
opening therein to allow it to be easily placed around the main body of 
the adaptor, since the lips at the ends of the adaptor may prevent a solid 
piece from such engagement. However, there may be more than one break such 
that piece(s) 45 may be more easily placed around the given annular lip of 
the adaptor. At least one solid piece 45 may be used if the diameters of 
the two ends of the cylindrical adaptor are of sufficiently different 
sizes. 
In the preferred embodiment shown in FIG. 7, an annular lip 35 is provided 
upon which discontinuous annular piece 45 comes to rest. An annular weld 
(that is discontinuous only at the break(s) 46 in piece 45) between piece 
45 and flange 34 is preferred for maximum attachment security. 
In the alternative embodiments of FIGS. 4, 7, 8, 9, 13 and 17 annular steel 
piece 45 has different cross sectional shapes, ranging from modified "Z" 
and other poly-sided shapes (including a modified "V"), which conform 
closely with the shapes of flange 34 and lip 36, to round, semi-circular 
and rectangular cross sections each having operable advantages such as low 
cost of manufacture, ease of assembly, and ease in formation. The annular 
steel piece 45 of each of these embodiments is welded to flange 34. 
In the alternative embodiments of FIGS. 5 & 10 a molded annular steel piece 
45 is attached to flange 34 using a rivet, pin or screw 51. 
In the alternative embodiments of FIGS. 6, 15 and 19 (and 19A) piece 45 is 
in the form of an annular C-shaped clamp made of formed steel. The bottom 
of piece 45 is welded to flange 34 as shown in FIG. 6; and a series of 
discontinuous clips 47, each welded at the bottom, are shown in FIGS. 19 
and 19A. Alternatively, the bottom of piece 45 may be exaggerated, as 
shown in FIG. 15, so that no weld is required for attachment. In each of 
these three embodiments, housing 32 has no annular flange 34, and 
diaphragm 40 is sandwiched between housing 32 and adaptor 35 and held in 
place by clamp piece 45. 
In the alternative embodiments of FIGS. 11 and 12 a set of tangs are used 
instead of a weld. The embodiment of FIG. 11 uses a set of protruding 
tangs 52 which fit into a set of corresponding notches 38 in flange 34. In 
the embodiment of FIG. 12, a set of protruding tangs 53 are die punched 
into flange 34 whereby lip 36 of adaptor 35 is snapped into place. 
In the alternative of FIG. 14, lamanate carbon fiber 55 is molded into an 
annular ring around flange 34 and the lower leg and lip 36 of adapter 35. 
The preferred method of attaching the aluminum adaptor to the housing 
requires that the spring housing cup 32 have an annular shoulder 33 and an 
axially protruding flange 34. The housing may be created by stamping from 
a steel sheet, or another suitable process. The adaptor base 35 is cast 
from aluminum, although in alternative embodiments it may be made from 
steel or other ferrous or non-ferrous material. The adaptor 35 should have 
an outwardly extending annular lip 36 the outside diameter of which is 
slightly smaller than the inside diameter of flange 34. The flanged lip 
can have a configuration that is angled, grooved, drilled, chamfered, 
machined or as cast. Finally, an annular retaining piece 45 is provided 
which may be formed, cast, stamped, rolled, punched or machined. It may be 
made from ferrous or non-ferrous material, and may have at least one break 
therein to facilitate placing it over the adaptor base. The 
cross-sectional shape of piece 45 may be round, square, rectangular, 
semi-circular, strip, or poly-sided. It should have a diameter roughly the 
same as the annular lip 36 such that it fits snugly inside flange 34 with 
good metal-to-metal contact. It should also have good metal to metal 
contact where it overlaps lip 36. 
The following common components of the brake actuator system are also 
assembled into the housing: the main compression spring; a flexible 
diaphragm 40 having roughly the same diameter as the lip 36; an adaptor 
base return spring; an intermediate push rod; a push rod plate; 0-rings; a 
pressure plate; a screw and push rod; and grease. It is preferred that the 
diaphragm may have a slightly thickened outer edge. 
The first step in attaching the adaptor to the emergency brake housing 32 
is placement of the housing in a cold environment such as a heat sink with 
its open flanged end facing upward. The main spring 27 is compressed into 
the housing and secured by a retaining tool in a fixture. The adaptor base 
sub-assembly is made of the return spring 29, intermediate push rod 28, 
push rod plates, O-rings, screws, push rod 25, and grease (See exploded 
view of FIG. 2). Diaphragm 40 is then inserted into the housing such that 
its thickened edges are along the shoulder below the annular flange. The 
adaptor base 35 and sub-assembly is then placed into the spring housing 
such that the annular lip 36 fits snugly inside annular flange 34, and is 
resting on top of the thick edges of diaphragm 40. Force of approximately 
1000 pounds is then applied to these components using either a pneumatic, 
mechanical, hydraulic or electrical ram sufficient to create a seal 
between the adaptor base sub-assembly and the diaphragm 40. Then, annular 
retaining piece(s) 45 are placed around adaptor 35 so that it (they) come 
into contact with the annular lip 36 of the adaptor 35 inside flange 34. A 
second force is then applied to the retainer piece itself which causes 
good metal-to-metal contact between the piece(s) 45 and both the flange 34 
and lip 36. This and can be accomplished using mechanical clamps, 
electromagnetism, or external pressure. While under this second force, 
piece 45 is fused to the flange of the housing. This may be accomplished 
using a gas tungsten arc welder, or other processes such as gas metal arc 
welding, arc welding and shield arc welding, oxyfuel gas welding, brazing, 
soldering, spot, laser beam or the like. A semi-automated welding 
apparatus may be used which incorporates a thermally cooled block (heat 
sink) that is shaped to reduce the thermal conduction into the diaphragm. 
This heat sink helps prevent deformation or destruction of the diaphragm 
from the heat of the welding process. The weld times, speeds, wire feeds, 
gas flows, power sources and voltages are parameters set to reduce the 
thermal load into the diaphragm. The power sources can be either 
continuous or pulse phase welders. The wire used in the welding process 
could be either solid or flux cored. After a brief cooling period, the 
pressure is released, and the attached adaptor and housing assembly may be 
removed, tested, cleaned and painted. 
A similar series of steps are followed to assemble the service brake 
housing 31 and attach it to the opposite end of the adaptor 35 (see 
exploded view of FIG. 2). 
The fusing of part 45 may be accomplished in at least two different ways. 
In the preferred method, part 45 is tack fused to the flange while the 
second force is still holding part 45 in place. This force is then 
removed, making all of part 45 available for fusing. In the other method, 
full fusing is performed while the second force is being applied. 
Several alternative embodiments of the apparatus are also available. 
Retaining piece 45 may be made in one of several different configurations 
having different cross sectional shapes such as circular, semi-circular, 
rectangular, square or poly-sided. A second annular lip 37 may be provided 
on adaptor 35 as shown in FIG. 3 in order to form a more secure connection 
between retaining piece 45 and adaptor 35, especially during the fusing 
process. Retainer piece 45 may be in the form on an "L" which is co-molded 
with the cast aluminum adaptor piece as shown in FIG. 16. This embodiment 
also includes the second annular lip 37 which holds co-molded piece 45 in 
place. 
Another embodiment of both the method and apparatus utilizes pins, screws 
or rivets to connect the retainer piece 45 to the flange 34, as shown in 
FIGS. 5 and 10, without the use of any welding. Yet another embodiment of 
both the method and apparatus employs the use of a set of tangs 53 which 
are die punched into flange 34 so that lip 36 of adaptor 35 may be snapped 
into place (see FIG. 12). Still another alternative embodiment employs a 
set of protruding tangs 52 which fit into a set of corresponding notches 
38 in flange 34 (see FIG. 10). Another embodiment utilizes a C-clamp that 
is either clipped or welded into place to hold the housing to the adaptor 
(see FIG. 6 and 15); this clamp may also be in the form of discontinuous 
clips which are each welded to the housing (see FIGS. 19 and 19A). 
Lamanate carbon fiber 55 may be molded into an annular ring around flange 
34 and the lower leg and lip 36 of adapter 35 as shown in FIG. 14. 
The present invention is equally useful for either aluminum or steel 
adaptor parts 35. The present invention may also be used on such products 
as piston brakes which use a solid piston rather than a flexible 
diaphragm. 
It is to be understood that variations and modifications of the present 
invention may be made without departing from the scope thereof. It is also 
to be understood that the present invention is not to be limited by the 
specific embodiments disclosed herein, but only in accordance with the 
appended claims when read in light of the foregoing specification.