Air Pump with Low Pressure Gauge Protective Device

Abstract

An air pump includes a inflating device, a pressure gauge, and a protective device. The inflating device includes a base, an inlet portion, a detection portion, and an outlet portion. The pressure gauge is mounted on the detection portion. A passage is interconnected with the inlet, detection and outlet portions. The protective device is disposed in the passage and includes a body and a sliding member. The body includes a slot and a hole. The sliding member inserts into the slot and is movable relative to the base to adjust a gap size between the base and the body for controlling air flow pressure in an affordable range of the pressure gauge.

1 . An air pump comprising:
 an inflating device including a base, a cylinder, a piston rod, an inlet portion, a detection portion, and an outlet portion, with an end of the cylinder connected to the base, with the piston rod slidably disposed inside the cylinder, with the inlet portion arranged at the base and engaged with the cylinder, with a passage arranged at the base and including a first section, a second section, and third section interconnected with each other, with the first section interconnected with the inlet portion, with the second section interconnected with the detection portion, with the third section interconnected with the outlet portion;   a pressure gauge mounted on the detection portion; and   a protective device disposed in the passage and including a body and a sliding member, with an outer periphery of the body airtightly abutted against an inner periphery of the passage, with the body including first and second ends spaced from each other, a slot, and a hole, with the first end of the body located adjacent to the inlet portion, with the slot extending from the first end of the body to the second end of the body, with the hole located between the first and second ends of the body and interconnected with the slot and the inlet portion, with the sliding member including first and second ends spaced from each other, a wide section, and a narrow section, with the first end of the sliding member inserting into the slot via the first end of the body, with the first end of the sliding member located between the hole and the second end of the body and airtightly abutted against an inner periphery of the slot, with the second end of the sliding member protruding out of the slot and forming the wide section, with a width of the wide section not less than a width of the slot, with the narrow section located between first and second ends of the sliding member, with a width of the narrow section less than the width of the slot.   
     
     
         2 . The air pump as claimed in  claim 1 , with the protective device further including a stopper and a biasing member, with the stopper located at the second end of the body and threadly engaged in the slot to seal a side of the slot adjacent to the second end of the body, with the stopper rotatable to synchronously move in the slot along an axis of the body, with the biasing member arranged between the sliding member and the stopper, and with two opposite ends of the biasing member respectively biasing against the sliding member and the stopper to push the sliding member moving away from the stopper. 
     
     
         3 . The air pump as claimed in  claim 2 , wherein the biasing member is a spiral spring. 
     
     
         4 . The air pump as claimed in  claim 2 , with the protective device further including a guiding member disposed in the passage and facing to the wide section of the sliding member, with the guiding member including a plurality of retaining walls abutted against the inner periphery of the passage, and with every two of the retaining walls forming a channel linearly extending therethrough. 
     
     
         5 . The air pump as claimed in  claim 4 , with a pressure measurement upper limit value of the pressure gauge less than 30 PSI. 
     
     
         6 . The air pump as claimed in  claim 5 , with the inflating device including a recess formed in the base, and with a manifold mounted in the recess and forming the passage linearly extending therethrough. 
     
     
         7 . The air pump as claimed in  claim 6 , with the base including a bottom surface and a top surface spaced from each other, with the bottom surface adapted to be seated on the ground, with the recess extending from the bottom surface to the top surface of the base, and with the pressure gauge mounted on the base and displayed on the top surface. 
     
     
         8 . The air pump as claimed in  claim 7 , with the protective device received in the detection portion. 
     
     
         9 . The air pump as claimed in  claim 7 , with the inlet portion and the detection portion respectively disposed on two opposite ends of the top surface of the base and intercommunicated with the recess. 
     
     
         10 . The air pump as claimed in  claim 8 , with the outlet portion disposed between the inlet portion and the detection portion on the top surface of the base and interconnected with the recess, with the outlet portion connected to a hose, and with an end of the hose opposite to the outlet portion connected to a nozzle. 
     
     
         11 . The air pump as claimed in  claim 6 , with the pressure gauge engaged in an adapting portion, with a bottom of the adapting portion connected to an extension tube configured to connected with the base, and with the protective device received in the extension tube. 
     
     
         12 . The air pump as claimed in  claim 11 , with a side of the adapting portion connected with a holding portion, and with the holding portion arranged around a periphery of the cylinder.