Pneumatic safety circuit for air inflation devices
AssigneeBruno Wessel Limited
InventorMichael C. Mohs
Life of this patent
Estimating the term…
Abstract
The invention provides a pneumatically operated circuit for automatically shutting off the flow of high pressure air being introduced into an object such as a tire, when the pressure in the object reaches a preselected maximum pressure significantly below the high pressure supply. The air is introduced automatically in timed, high pressure bursts and between the time bursts a safety mechanism gauges the pressure that has built up in the object and interrupts further timed bursts when the latter pressure exceeds the preselected maximum.
Claims13
A safety circuit for air inflation devices having a high pressure pneumatic supply line connected to an object to be inflated to a pressure significantly lower than the supply line pressure, through an operator controlled valve in said high pressure pneumatic supply line, said safety circuit comprising:
- (1) a first pneumatic duct connecting high pressure air from the outlet of said operator controlled valve to the inlet of a spring biased, normally closed, pilot operated, 3-way valve,
- (2) a second pneumatic duct connecting high pressure air from an outlet of said pilot operated 3-way valve to an object to be inflated when said pilot operated 3-way valve is in opened position, a second outlet of said pilot operated 3-way valve also connecting said object to be inflated to a pneumatic safety line, when said pilot operated 3-way valve is in closed position,
- (3) a third pneumatic duct connecting the outlet of said operator controlled valve to the inlets of each of a pair of 3-way pilot operated delay valves, the first said 3-way delay valve being a spring biased, normally open valve, the second said 3-way delay valve being a spring biased normally closed valve, the delay time of the first said 3-way delay valve being significantly different from the delay time of the second said 3-way delay valve,
- (4) a fourth pneumatic duct connecting an outlet of the first said 3-way delay valve to the pilot side of said second 3-way delay valve when the first said 3-way delay valve is in opened position, the first said 3-way delay valve connecting said fourth pneumatic duct to an atmospheric discharge when in closed position,
- (5) a fifth pneumatic duct connecting an outlet of the second said 3-way delay valve to the pilot side of said pilot operated 3-way valve when the second said 3-way delay valve is in opened position, the second said 3-way delay valve connecting said fifth pneumatic duct to an atmospheric discharge when in closed position,
- (6) a sixth pneumatic duct connecting the said outlet of the said second 3-way delay valve to the pilot side of said first 3-way delay valve when the second said 3-way delay valve is in opened position,
- (7) the pneumatic safety line connecting said second outlet of said pilot operated 3-way valve to the inlet of a relief valve means adapted to discharge the pressure in said safety line at a preselected pressure,
- (8) a seventh pneumatic duct connecting the discharge of said relief valve means to valve means which prevents further flow of high pressure air from the operator controlled valve to the object to be inflated.
Dependencies are inferred from the claim text.