Measuring and testing – Spring testing
Patent
1995-12-12
1998-02-03
DePumpo, Daniel G.
Measuring and testing
Spring testing
73121, 188 111, 92 63, G01L 104, G01L 528
Patent
active
057132380
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF INVENTION
1. Field of the Invention
This invention relates to a spring brake actuator with a gauge for measuring the spring force of a power spring in the actuator. In one of its aspects, the invention relates to a method for measuring the force of a spring in a spring brake actuator. In another of its aspects, the invention relates to a gauge for measuring the force of a spring in a spring brake actuator.
2. State of the Prior Art
Spring brake actuators are in common use with air brake systems used on trucks, buses, and towed vehicles. Such actuators normally include a service brake actuator for applying and releasing the brakes in response to delivery and exhaust of compressed air and a spring brake actuator disposed in tandem with the service brake actuator. The spring brake actuator uses spring force to operate the service brake actuator and apply the brakes when the air in a spring brake actuator chamber is reduced below a predetermined pressure. Air pressure may be reduced in this chamber under the control of the operator to apply the brakes or automatically as a result of failure of portions of the service brake air system.
Typically, a barrel-shaped spring is used to store energy and to exert the large force required for braking in the event of air pressure failure. Air pressure in the chamber acting on a movable wall is employed to compress the spring and maintain it in a retracted position. When the air is exhausted from the chamber, the spring acts on the movable wall, typically a diaphragm or a piston, and through an actuating rod to exert the spring force on the service actuator to apply the brakes.
It is desirable to measure the spring force of the spring to ensure that it is operating within design parameters. However, disassembly of the spring brake actuator to remove the spring and test it outside the actuator does not measure its operating effectiveness on the vehicle. Moreover, many spring brake actuators now permanently enclose the power spring, making removal of the spring for testing purposes impractical.
SUMMARY OF THE INVENTION
According to the invention, a gauge measures the force of a power spring in a spring brake actuator comprising a housing having an end wall, a spring plate disposed within the housing, a power spring between the spring plate and housing end wall, and a caging bolt extending from the spring plate through the housing end wall and having a nut thereon exterior of the housing. The gauge comprises a pressure-responsive element adapted to be positioned between the caging bolt nut and the spring housing for generating a signal representative of the compressive force of the spring and an indicator coupled to the pressure-responsive element to visually display the force of the spring as a function of the pressure signal. Typically, the pressure-responsive element comprises a first member adapted to receive the nut in abutting engagement and a second member adjacent the first member and adapted to abut the housing. The first member is movable relative to the second member in response to compressive force applied to the nut by the power spring acting against the spring plate. The gauge measures the compressive force between the nut and the spring housing so that the force applied by the power spring can be measured in situ. The invention provides quick and accurate in situ measurement of the force of the power spring. Also, measuring the force of the spring with the brake installed in its operating environment improves accuracy over measurements taken on brakes removed from the vehicle.
Preferably, the first and second members each have an aperture aligned to slidably receive the caging bolt. Also, the second member preferably comprises a body having a bore, the first member comprises a piston received within the bore, and the gauge further comprises a pressure-responsive fluid between the piston and the body for resisting an applied compressive force and the pressure signal is a fluid pressure. The indicator is connected to the pressure-responsive flu
REFERENCES:
patent: 2291561 (1942-07-01), Reiss
patent: 3834228 (1974-09-01), Wachholz
patent: 3978722 (1976-09-01), Glotzl et al.
patent: 4196623 (1980-04-01), Alinari
patent: 4658936 (1987-04-01), Moseley
patent: 4805740 (1989-02-01), Wilke et al.
patent: 4945818 (1990-08-01), Ware
patent: 4989537 (1991-02-01), Hutchinson, Sr. et al.
patent: 5002164 (1991-03-01), Bowyer
Hicks William J.
Pierce William C.
DePumpo Daniel G.
Hirshfeld Andrew
NAI Anchorlok Inc.
LandOfFree
Spring brake actuator with spring force measurement does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Spring brake actuator with spring force measurement, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spring brake actuator with spring force measurement will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-654082