Tire automatic pneumatic pump device

• US 5,342,177 A
• Filed: 04/01/1992
• Issued: 08/30/1994
• Est. Priority Date: 04/01/1992
• Status: Expired due to Fees

• Current Assignee: Chen-Kuang Cheng
• Original Assignee: Chen-Kuang Cheng
• Inventors: Cheng, Chen-Kuang
• Primary Examiner(s): Bertsch, Richard A.
• Assistant Examiner(s): Basichas, Alfred
• Application Number:
  US07/861,909
• Time in Patent Office: 881 Days
• Field of Search: 417/233, 280/288.4, 280/304.2
• US Class Current: 417/233
• CPC Class Codes: B60C 23/127 the pumps being mounted on the hubs
• CPC Class Codes: B60C 23/137 comprising cam driven pistons
• CPC Class Codes: F04B 33/005 specially adapted for inflating tyres of non-motorised vehicles, e.g. cycles, tricycles
• CPC Class Codes: F04B 49/022 by means of pressure

Abstract

An automotive bicycle tire pump is disclosed in which a cylinder and piston assembly rotates with the wheel rim and tire. The piston is reciprocated by contact with a stationary cam to provide pressurized air to the tire. When the proper tire pressure is reached, the piston is automatically latched in a position out of contact with the cam to prevent reciprocation of the piston.

Claims

1. An automatic pump for a pneumatic tire mounted on a rim having a hub attached to and rotatable with respect to a stationary axle, comprising:

a) an eccentric drive cam fixedly attached to the stationary axle;

b) a pneumatic pump assembly attached to the hub so as to rotate therewith, the pneumatic pump assembly comprising;

i) a hollow pneumatic cylinder attached to the hub;

ii) a first piston slidably located within the pneumatic cylinder, the first piston defining a recess in a first end and having a second end;

iii) a second piston slidably located in the recess of the first piston;

iv) biasing means to normally bias the first piston into contact with the drive cam such that rotation of the pump assembly causes the cam to reciprocate the first piston within the pneumatic cylinder thereby compressing air within the pneumatic cylinder; and

,

v) latching means actuated by relative movement between the first and second pistons to latch the first piston in a position out of contact with the drive cam thereby preventing reciprocation of the first piston;

c) means defining a first air flow passage between the pneumatic cylinder and the tire;

d) first valve means located in the first air flow passage and comprising a one way valve to allow air compressed by the first piston to flow from the pneumatic cylinder into the tire, but prevent flow in the reverse direction;

e) means defining a second air flow passage between the first air flow passage and the second piston; and

,

f) second valve means permitting air flow from the tire to the second piston such that, when the tire pressure reaches a predetermined level, the second piston moves relative to the first piston to activate the latching means, thereby preventing additional compressed air from being supplied to the tire.

2. The automatic pump of claim 1 wherein the latching means comprises:

a) a neck ring attached to the pneumatic cylinder and defining an edge;

b) a tapered portion formed on the second piston; and

,

c) at least one latching element attached to the first piston such that relative movement between the first and second pistons causes the tapered portion of the second piston to urge the at least one latching element into contact with the edge of the neck ring.

3. The automatic pump of claim 2 wherein the at least one latching element comprises a plurality of ball members.

4. The automatic pump of claim 1 further comprising a movable ball attached to the second end of the first piston so as to contact the drive cam.

5. The automatic pump of claim 1 further comprising means to adjust the second valve means so as to adjust the predetermined level of air pressure to be maintained in the tire.