U.S. patent application number 10/131855 was filed with the patent office on 2002-08-29 for blended electrical/friction braking system with electric brake feedback monitor and method of use thereof.
Invention is credited to Ames, Richard P., Barbour, Theresa A., Chang, Steven TH., Langovsky, Nikola V., Madden, William E. JR., Phillips, Robert W., Zuber, Pierre A..
Application Number | 20020117984 10/131855 |
Document ID | / |
Family ID | 24238038 |
Filed Date | 2002-08-29 |
United States Patent
Application |
20020117984 |
Kind Code |
A1 |
Zuber, Pierre A. ; et
al. |
August 29, 2002 |
Blended electrical/friction braking system with electric brake
feedback monitor and method of use thereof
Abstract
A blended electrical/friction braking system includes an
electric brake feedback monitor which monitors a first signal
corresponding to an electric brake effort request of an electric
motor of an electrically powered vehicle. The electric brake
feedback monitor detects one or more electrical conditions of the
electric motor during electric braking and selectively
supplies/terminates the first signal to/from a brake controller as
a function of the first signal and the one or more electrical
conditions. In response to termination of the first signal thereat,
the brake controller causes a friction brake of the vehicle to
assume the entire braking effort of the vehicle.
Inventors: |
Zuber, Pierre A.; (Bethel
Park, PA) ; Ames, Richard P.; (Jefferson Hills,
PA) ; Langovsky, Nikola V.; (Clairton, PA) ;
Madden, William E. JR.; (Pittsburgh, PA) ; Chang,
Steven TH.; (Export, PA) ; Phillips, Robert W.;
(Jefferson Hills, PA) ; Barbour, Theresa A.;
(Monroeville, PA) |
Correspondence
Address: |
Webb Ziesenheim Logsdon Orkin & Hanson, P.C.
Suite 700
436 Seventh Avenue
Pittsburgh
PA
15219
US
|
Family ID: |
24238038 |
Appl. No.: |
10/131855 |
Filed: |
April 25, 2002 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10131855 |
Apr 25, 2002 |
|
|
|
09560493 |
Apr 28, 2000 |
|
|
|
Current U.S.
Class: |
318/375 |
Current CPC
Class: |
B60L 7/26 20130101; B60L
2200/26 20130101 |
Class at
Publication: |
318/375 |
International
Class: |
H02P 003/12; H02P
003/14; H02P 003/18 |
Claims
We claim:
1. A brake feedback monitor for monitoring a first signal
corresponding to an electric brake effort request of an electric
motor of an electrically powered vehicle, for monitoring one or
more electrical conditions of the electric motor in response to the
electric brake effort request, and for selectively
supplying/terminating the first signal to/from a brake controller
as a function of the first signal and the one or more electrical
conditions.
2. The brake feedback monitor as set forth in claim 1, further
including: a first relay having a contact in series with a path of
the first signal, and a first control input for receiving a first
control signal which controls the state of the first relay contact;
and a first processor connected for monitoring the first signal,
for monitoring the one or more electrical conditions, for
converting the monitored one or more electrical conditions into a
second signal, for determining if a difference between the first
signal and the second signal exceeds a predetermined difference and
for supplying the first control signal, wherein the first control
signal causes the first relay contact to assume one state when the
difference does not exceed the predetermined difference and which
causes the first relay contact to assume another state when the
difference exceeds the predetermined difference.
3. The brake feedback monitor as set forth in claim 2, further
including: a second relay having a contact in series with the path
of the first signal, and a first control input for receiving a
second control signal which controls the state of the second relay
contact; and a second processor connected for monitoring the first
signal, for receiving the second signal from the first processor,
for determining if a difference between the first signal and the
second signal exceeds a predetermined difference and for supplying
the second control signal, wherein the second control signal causes
the second relay contact to assume one state when the difference
does not exceed the predetermined difference and which causes the
second relay contact to assume another state when the difference
exceeds the predetermined difference.
4. The brake feedback monitor as set forth in claim 3, wherein: the
one state of each relay is the closed state; and the other state of
each relay is the opened state.
5. The brake feedback monitor as set forth in claim 4, wherein: the
second relay has a second control input for receiving a third
control signal for controlling the state of the second relay
contact; and the first relay has a second control input for
receiving a fourth control signal for controlling the state of the
first relay contact.
6. The brake feedback monitor as set forth in claim 5, wherein in
response to detecting the presence of the first signal after
supplying the first control signal for causing the first relay
contact to assume its opened state, the first processor supplies
the third control signal to the second relay for causing the second
relay contact to assume its opened state.
7. The brake feedback monitor as set forth in claim 5, wherein in
response to detecting the presence of the first signal after
supplying the second control signal for causing the second relay
contact to assume its opened state, the second processor supplies
the fourth control signal to the first relay for causing the first
relay contact to assume its opened state.
8. The brake feedback monitor as set forth in claim 5, wherein:
each relay includes a status output which provides a status of the
state of the contact thereof, the status output of the first relay
is connected to the first processor and the status output of the
second relay is connected to the second processor; and at least one
of: (i) after supplying the first control signal for causing the
first relay contact to assume its opened state and in response to
detecting via the status output of the first relay that the first
relay contact is in its closed state, the first processor supplies
the third control signal to the second relay for causing the second
relay contact to assume its opened state; and (ii) after supplying
the second control signal for causing the second relay contact to
assume its opened state and in response to detecting via the status
output of the second relay that the second relay contact is in its
closed state, the second processor supplies the fourth control
signal to the first relay for causing the first relay contact to
assume its opened state.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of United States patent
application Ser. No. 09/560,493, filed Apr. 28, 2000.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a blended
electrical/friction braking system of an electric motor powered
vehicle and, more particularly, to a system which monitors a
regenerative/dynamic braking effort of the electric motor and which
operates the friction brake of the vehicle as a function
thereof.
[0004] 2. Background Art
[0005] An electrically powered vehicle, such as an electrically
powered mass transit vehicle, typically includes an AC or DC
electric motor for propelling the vehicle along a path or running
rails. During acceleration or constant speed operation of the
vehicle, electrical power is controllably supplied to the electric
motor. When it is desired to brake the vehicle, the momentum of the
vehicle can be utilized to drive the electric motor as a generator
for generating electric power which is supplied for use by other
electrical/electronic devices and/or for storage in a storage
device, such as a battery or capacitor, or for dissipation by a
suitable load. The use of the electric motor as a generator to
convert the momentum of the vehicle into electric power for such
use and/or storage is commonly known as regenerative braking. The
use of the electric motor as a generator to convert the momentum of
the vehicle into electric power for dissipation by a load is
commonly known as dynamic braking. Hereinafter, phrases such as
"electrical braking", "electric braking", "electrically braking",
"electrically brake" and the like, are utilized to refer to driving
the "electric motor in a dynamic braking mode and/or a regenerative
braking mode.
[0006] Such a vehicle would also include a friction brake which is
utilized in a blended manner with the electric motor to brake the
wheels of the vehicle in a manner known in the art. In operation,
the electric motor is utilized for electrically braking the vehicle
at higher speeds where the electric motor can be used more
effectively and the friction brake is utilized to brake the vehicle
at lower speeds where the electric motor is less effective. Blended
electrical/friction braking systems are well-known in the art.
[0007] A problem with such blended electrical/friction braking
systems, however, is that if the actual extent of electric braking
does not correspond to the requested/expected extent of electric
braking, no mechanism exists for detecting this lack of
correspondence and for causing the friction braking to assume the
overall braking effort of the vehicle.
[0008] It is, therefore, an object of the present invention to
provide a blended electrical/friction braking system having a brake
feedback monitor for monitoring a difference between a requested
electric braking effort of an electric motor of a vehicle and the
actual electric braking effort of the motor and for causing a
friction brake of the vehicle to assume the entire braking effort
if the difference exceeds a predetermined difference. Still other
objects of the present invention will become apparent to those of
ordinary skill in the art upon reading and understanding the
following detailed description.
SUMMARY OF THE INVENTION
[0009] Accordingly, we have invented a blended electrical/friction
braking system for use in a vehicle having an electric motor which
can be operated to electrically brake one or more wheels of the
vehicle and a friction brake for friction braking one or more
wheels of the vehicle. The braking system includes a brake
controller for monitoring a brake effort request and for allotting
the brake effort request between a first brake effort request
corresponding to a desired amount of electrical braking effort to
be supplied by the electric motor during electric braking and a
second brake effort request corresponding to a desired amount of
friction braking effort to be supplied by the friction brake. A
drive control unit produces from the first brake effort request a
first signal corresponding thereto and supplies the first signal to
the brake controller. One or more sensors sense one or more
electrical conditions of the electric motor during electrical
braking. A brake feedback monitor monitors the first signal,
converts the one or more sensed electrical conditions into a second
signal corresponding thereto, compares the first signal and the
second signal and terminates receipt of the first signal by the
brake controller in response to a difference between the first
signal and the second signal exceeding a predetermined difference.
The brake controller responds to the termination of the first
signal thereat by allotting the incoming brake effort request
entirely to the second brake effort request. The one or more sensed
electrical conditions of the electric motor can include voltage(s),
current(s) and/or phase angle(s) therebetween.
[0010] The brake feedback monitor can include a processor and a
relay connected to the processor to be controlled thereby. The
relay has a contact in a path of the first signal between the drive
control unit and the brake controller. The processor controls the
contact so that (i) the brake controller receives the first signal
when the difference between the first signal and the second signal
does not exceed the predetermined difference and (ii) the brake
controller does not receive the first signal when the difference
between the first signal and the second signal exceeds the
predetermined difference.
[0011] The brake feedback monitor can also include a pair of relays
connected in series in the path of the first signal between the
drive control unit and the brake controller and a pair of
processors each connected to control the contacts of the pair of
relays and connected to sense the first signal on the path between
the pair of relays and the brake controller. One processor
determines the second signal from the one or more sensed electrical
condition and supplies the second signal to the other processor.
Each processor can determine whether the difference between the
first signal and the second signal exceeds the predetermined
difference. In response to determining the difference exceeds the
predetermined difference, each processor can signal one relay to
change state thereby terminating receipt of the first signal by the
brake controller.
[0012] Each relay can include a status output connected to one of
the processors for supplying thereto an indication of the state of
the contact of the relay. Each processor can signal the other relay
to change state if the status output of the one relay does not
indicate that the one relay is in a state that terminates receipt
of the first signal by the brake controller. Moreover, each
processor, in response to detecting the first signal after
signaling the one relay to change state, can signal the other relay
to change state. Preferably, the first and/or second signals are
pulse width modulated signals.
[0013] We have also invented a brake feedback monitor for
monitoring a first signal corresponding to an electric brake effort
request of an electric motor of an electrically powered vehicle,
for monitoring one or more electrical conditions of the electric
motor in response to the electric brake effort request, and for
selectively supplying/terminating the first signal to/from a brake
controller as a function of the first signal and the one or more
electrical conditions.
[0014] The brake feedback monitor can include a first relay having
a contact in series with a path of the first signal and a first
control input for receiving a first control signal which controls
the state of the first relay contact. A first processor can be
connected to monitor the first signal and to monitor the one or
more electrical conditions. The first processor can convert the
monitored one or more electrical conditions into a second signal
and can determine if a difference between the first signal and the
second signal exceeds a predetermined difference. The first
processor can also supply the first control signal to the first
relay for causing the first relay contact to assume one state when
the difference does not exceed the predetermined difference and for
causing the first relay contact to assume another state when the
difference exceeds the predetermined difference.
[0015] The brake feedback monitor can also include a second relay
having a contact in series with the path of the first signal and a
first control input for receiving a second control signal which
controls the state of the second relay contact. A second processor
can be connected for monitoring the first signal and for receiving
the second signal from the first processor. The second processor
can also determine if a difference between the first signal and the
second signal exceeds a predetermined difference. The second
processor can supply the second control signal for causing the
second relay contact to assume one state when the difference does
not exceed the predetermined difference and for causing the second
relay contact to assume another state when the difference exceeds
the predetermined difference. Preferably, the one state is a closed
state and the other state is the opened state.
[0016] The second relay can have a second control input for
receiving a third control signal which controls the state of the
second relay contact. The first relay can have a second control
input for receiving a fourth control signal which controls the
state of the first relay contact.
[0017] In response to detecting the presence of the first signal
after supplying the first control signal for causing the first
relay contact to assume its opened state, the first processor can
supply the third control signal to the second relay for causing the
second relay contact to assume its opened state. Similarly, in
response to detecting the presence of the first signal after
supplying the second control signal for causing the second relay
contact to assume its opened state, the second processor can supply
the fourth control signal to the first relay for causing the first
relay contact to assume its opened state.
[0018] Each relay can also include a status output which provides a
status of the state of the contact thereof. The status output of
the first relay is connected to the first processor and the status
output of the second relay is connected to the second processor.
After supplying the first control signal for causing the first
relay contact to assume its opened state and in response to
detecting via the status output of the first relay that the first
relay contact is in its closed state, the first processor can
supply the third control signal to the second relay for causing the
second relay contact to assume its opened state. Similarly, after
supplying the second control signal for causing the second relay
contact to assume its opened state and in response to detecting via
the status output of the second relay that the second relay contact
is in its closed state, the second processor can supply the fourth
control signal to the first relay for causing the first relay
contact to assume its opened state.
[0019] Lastly, we have invented a method of braking an electric
motor powered vehicle. The method includes allotting a brake effort
request between an electric brake effort request and a friction
brake effort request. The electric brake effort request is
converted into a first signal which is monitored along with one or
more electrical conditions of the electric motor in response to the
electric brake effort request. A feedback path for the first signal
is selectively opened/closed as a function of the first signal and
the one or more electrical conditions. In response to opening the
feedback path, the incoming brake effort request is allotted
entirely to the friction brake effort request.
[0020] The step of selectively opening/closing the feedback path
can include the steps of providing a pair of relays with each relay
having a contact disposed in series with the feedback path and a
status output which provides a status of the state of the contact
thereof. One relay can be signaled to open its contact as a
function of the first signal and the one or more electrical
conditions. Thereafter, in response to detecting the presence of
the first signal downstream in the feedback path from the one relay
and/or the status output of the one relay that its contact is
closed, the other relay can be signaled to open its contact.
[0021] The one or more electrical conditions can be converted into
a second signal and a difference between the first signal and the
second signal can be determined. The feedback path can be closed
when the difference does not exceed a predetermined difference and
the feedback path can be opened when the difference exceeds the
predetermined difference.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a side view of an electrically powered mass
transit vehicle; and
[0023] FIG. 2 is a schematic drawing of a blended
electrical/friction braking system including an electric brake
feedback monitor in accordance with the present invention which is
included in the mass transit vehicle shown in FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0024] With reference to FIG. 1, a prior art electrically powered
mass transit vehicle 2 includes an electric motor 4 for providing
motive force to one or more wheels 6 to propel vehicle 2 along a
path 8, such as a running rail. In the embodiment shown in FIG. 1,
vehicle 2 includes a pantograph 10 which is utilized to conduct
electric power from a supply line 12. Electric power conducted by
pantograph 10 is converted to electric power by apparatus, to be
hereinafter described, and provided to motor 4. Motor 4 converts
the electric power provided thereto into motive force of sufficient
extent to propel vehicle 2 along path 8. Alternatively, vehicle 2
can include an internal source of electric power (not shown) which
supplies electric power to motor 4. If vehicle 2 includes an
internal source of electric power, pantograph 10 and supply line 12
may be omitted from the embodiment shown in FIG. 1.
[0025] With reference to FIG. 2, and with ongoing reference to FIG.
1, each wheel 6 includes a friction brake 14 under the control of a
friction brake controller 16 connected to receive a brake effort
request signal from a brake pedal 18 or, in an attendantless
automated vehicle, from an automated electronic control, such as an
automated train control (ATC) 17. Friction brake controller 16
allots the brake effort request between an electric brake effort
request and a friction brake effort request. The combination of the
electric brake effort request and the friction brake effort request
correspond to the extent of the overall brake effort requested by
the brake effort request. The friction brake effort request is
supplied to a suitable friction brake system (not shown) which
controls the application of friction brakes 14 of vehicle 2 in a
manner known in the art. Such a friction brake system is well-known
in the art and will not be described further herein for simplicity
of discussion.
[0026] The electric brake effort request is supplied through a
vehicle control unit 20 for supply to a drive control unit 22 via a
multi-function vehicle bus (MVB). During acceleration or constant
velocity operation of vehicle 2, drive control unit 22 supplies
electric power to motor 4 in response to control signals received
from vehicle control unit 20. Vehicle control unit 20 can supply
control signals to drive control unit 22 as a function of an
operator input to vehicle control unit 20 by an operator of vehicle
2 or, in an attendantless automated vehicle, by the ATC 17. During
braking of vehicle 2 in response to receipt of the electric brake
effort request from friction brake controller 16, drive control
unit 22 operates motor 4 as a generator to electrically brake
vehicle 2. During electrical braking, drive control unit 22
generates a first signal T1 corresponding to the electric brake
effort request. First signal T1 is supplied by the drive control
unit 22 to the MVB for supply in a feedback mode to friction brake
controller 16 via vehicle control unit 20.
[0027] One or more motor sensors 24 are connected to sense one or
more electrical conditions of motor 4. The one or more sensed
electrical conditions are provided in a feedback mode to drive
control unit 22 which utilizes the one or more sensed electrical
conditions to control the operation of motor 4.
[0028] An electric brake feedback monitor 30 is connected in the
feedback path of signal T1 between vehicle control unit 20 and
friction brake controller 16 for monitoring signal T1. Electric
brake feedback monitor 30 is also connected to monitor the one or
more sensed electrical conditions during electric braking and to
convert the one or more sensed electrical conditions into a second
signal T2 corresponding thereto. During electric braking of vehicle
2, brake feedback monitor 30 compares signal T1 and signal T2 and
terminates receipt of signal T1 by friction brake controller 16 in
response to a difference between signal T1 and signal T2 exceeding
a predetermined difference. In response to termination of signal T1
thereat, friction brake controller 16 allots the brake effort
request entirely to the friction brake effort request. Hence, when
the difference between signal T1, corresponding to the electric
brake effort request of motor 4, and signal T2, corresponding to
the actual electric braking effort of motor 4 in response to the
dynamic brake effort request exceeds the predetermined difference,
the entire braking effort of vehicle 2 is transferred to friction
brakes 14.
[0029] Preferably, signal T1 and signal T2 are pulse width
modulated signals and the one or more sensed electrical conditions
includes motor voltage(s), motor current(s) and/or the phase
angle(s) therebetween.
[0030] Preferably, electric brake feedback monitor 30 also includes
a channel A processor 32 and a first relay 34. Relay 34 has a
contact 36 in the feedback path of signal T1 between drive control
unit 22 and friction brake controller 16. Channel A processor 32 is
connected to receive the one or more sensed electrical conditions
sensed by the one or more motor sensors 24 and is connected to the
feedback path of signal T1 preferably between contact 36 and
friction brake controller 16 for monitoring signal T1. Channel A
processor 32 is also connected to a control input of first relay 34
for controlling the opened/closed state of contact 36.
[0031] In operation, channel A processor 32 monitors signal T1,
converts the one or more sensed electrical conditions into signal
T2, and compares signal T1 and signal T2. By signaling the control
input of first relay 34 with a suitable first control signal,
channel A processor 32 controls contact 36 so that friction brake
controller 16 receives signal T1 when the difference between signal
T1 and signal T2 does not exceed the predetermined difference, and
the friction brake controller 16 does not receive signal T1 when
the difference exceeds the predetermined difference. More
specifically, when the difference does not exceed the predetermined
difference, channel A processor 32 signals the control input of
relay 34 with the first control signal to set or maintain contact
36 in its closed state. Similarly, when the difference exceeds the
predetermined difference, channel A processor 32 signals the
control input of relay 34 with the first signal to set or maintain
contact 36 in its opened state.
[0032] Preferably, electric brake feedback monitor 30 also includes
a channel B processor second relay 40. Channel B processor 38 and
channel A processor 32 are communicatively connected for enabling
status and data to be shared therebetween. More specifically, this
connection enables channel B processor 38 to receive signal T2 from
channel A processor 32. Second relay 40 has a contact 42 connected
in the feedback path of signal T1, preferably between contact 36
and friction brake controller 16.
[0033] Channel B processor 38 is connected to a control input of
second relay 40 for controlling the opened/closed state of contact
42. Channel B processor 38 is also connected to the feedback path
of signal T1 between contact 42 and friction brake controller 16
for monitoring signal T1. Since it receives signal T2 from channel
A processor 32, channel B processor 38 can compare signal T1 and
signal T2 without having to sense the one or more electrical
conditions generated by motor 4 during electrical braking. Channel
B processor 38 compares signal T1 and signal T2 and signals the
control input of second relay 40 with a suitable second control
signal to control the state of contact 42 so that friction brake
controller 16 receives signal T1 when the difference between signal
T1 and signal T2 does not exceed the predetermined difference and
friction brake controller 16 does not receive signal T1 when the
difference exceeds the predetermined difference. As discussed
above, when friction brake controller 16 does not receive signal
T1, friction brake controller 16 allots the brake effort request
entirely to the friction brake effort request.
[0034] Preferably, channel A processor 32 and channel B processor
38 are also connected to another control input of second relay 40
and to another control input of first relay 34 for controlling the
state of contacts 42 and 36, respectively. This cross connection of
channel A processor 32 to another control input of second relay 40
enables channel A processor 32 to open contact 42 if channel A
processor 32 detects signal T1 after signaling first relay 34 to
open contact 36. Thus, if contact 36 fails to open in response to
first relay 34 receiving a suitable first control signal from
channel A processor 32, channel A processor 32 signals the other
control input of second relay 40 with a suitable third control
signal to open contact 42. Similarly, the cross connection of
channel B processor 38 to another control input of first relay 34
enables channel B processor 38 to open contact 36 if channel B
processor 38 detects signal T1 after signaling second relay 40 to
open contact 42. Thus, if contact 42 fails to open in response to
second relay 40 receiving the second control signal from channel B
processor 38, channel B processor 38 signals the other control
input of first relay 34 with a suitable fourth control signal to
open contact 36.
[0035] Preferably, the first control signal from channel A
processor 32 and the fourth control signal from channel B processor
38 provide power and ground, respectively, to a coil 44 which
controls the state of contact 36 of first relay 34. Hence, by
selectively controlling the application of power and ground to coil
44, channel A processor 32 and channel B processor 38 can control
the state of contact 36. Similarly, the third control signal from
channel A processor 32 and the second control signal from channel B
processor 38 preferably provide power and ground, respectively, to
a coil 46 which controls the state of contact 42 of second relay
40. Thus, by selectively controlling the application of power and
ground to coil 46, channel A processor 32 and channel B processor
38 can control the state of contact 42.
[0036] Preferably, first relay 34 and second relay 40 each have a
status output connected for supplying to channel A processor 32 and
channel B processor 38 an indication of the state of contacts 36
and 42, respectively. In operation, channel A processor 32 monitors
via the status output of first relay 34 the state of contact 36. If
contact 36 did not open in response to channel A processor 32
signaling first relay 34 to open contact 36, channel A processor 32
can signal second relay 40 to open contact 42. Similarly, channel B
processor 38 monitors the status output of second relay 40. If
contact 42 did not open in response to channel B processor 38
signaling second relay 40 to open contact 42, channel B processor
38 can signal first relay 34 to open contact 36.
[0037] As shown in FIG. 2, first relay 34 and second relay 40 can
each have another status output connected to channel B processor 38
and channel A processor 32, respectively. These status outputs can
be utilized to supply to channel B processor 38 and channel A
processor 32 an indication of the state of contacts 36 and 42 of
first relay 34 and second relay 40, respectively.
[0038] As can be seen from the foregoing, the present invention
provides a brake feedback monitor for monitoring the difference
between the electric brake effort request of an electric motor of a
vehicle and the actual electrical braking effort of the motor in a
blended electrical friction braking system and for causing the
friction brake of the vehicle to assume the entire braking effort
of a vehicle if the difference exceeds a predetermined
difference.
[0039] The invention has been described with reference to the
preferred embodiment. Obvious modifications and alterations will
occur to others upon reading and understanding the preceding
detailed description. For example, channel A processor 32 and
channel B processor 38 can utilize different criteria and/or
algorithms to determine the difference between signal T1 and signal
T2. Hence, each processor 32 and 38 can have a different
sensitivity to the differences between signal T1 and signal T2. It
is intended that the invention be construed as including all such
modifications and alterations insofar as they come within the scope
of the appended claims or the equivalents thereof.
* * * * *