Pumps – With signal – indicator – or inspection means
Reexamination Certificate
1999-11-30
2001-03-06
Walberg, Teresa (Department: 3742)
Pumps
With signal, indicator, or inspection means
C417S313000, C073S146800
Reexamination Certificate
active
06196807
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a pressure gauge, and more particularly, to a pressure gauge of a bicycle tire pump, the pressure gauge having a tubular pressure indicator with a rubber made head portion attached thereto, wherein the head portion is slidably received in a chamber for the gauge and the pressure indicator is not in contact with an inner periphery defining the chamber so as to have less friction therebetween for providing accurate tire pressure indication.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 5,503,012 to Rabizadeh issued on Apr. 2, 1996 discloses a tire pressure monitoring device that includes a ball disposed within a tube which has an opening, at one end, in communication with the interior of the tire. The tube has a transparent window along its length to allow the position of the tire pressure ball to be visualized. The transparent window has graduations, calibrated to allow the tire pressure to be determined by the position of the ball. Nevertheless, reading of the tire pressure among the indicia is not easy, and an unskilled user may report a wrong tire pressure. In addition, the indicia on the transparent window tend to wear out after a term of use. In addition, the compression spring for attaching the ball is more or less rotated during movement of the ball due to the helical configuration of the compression spring. Namely, unexpected rotational movement of the compression occurs and thus affects the pressure indication accuracy.
U.S. Pat. No. 4,919,600 to Yang issued on Apr. 24, 1990 discloses a tire pump with a pressure gauge including a cylinder having a piston head slidably provided in the cylinder. A pressure measuring device with a pressure indicating element is disposed at a front end of the cylinder so that the pressure indicating element is readable through a peep hole in the cylinder. The pressure measuring device interconnects an outlet of the cylinder. A bypass tube with a check valve is disposed beside the pressure measuring device so that air pressurized by the piston head flows out from the outlet through the bypass tube. The pressurized air also flows through air holes in order that the pressure within the pumped tire can be read from the pressure indicating element of the pressure measuring device through the peep hole. Again, the compression spring for attaching the pressure indicating element is more or less rotated during movement of the pressure indicating element due to the helical configuration of the compression spring. Unexpected rotational movement of the compression occurs and thus affects the pressure indication accuracy. The pressure indicating element includes a scale attached to a piston, wherein the scale tends to break during use, and the manufacture cost for such a pressure indicating element is relatively high.
FIG. 1
of the drawings illustrates another conventional arrangement of a pressure indicator
50
that is square in section and is slidably received in a chamber
51
with square section. The pressure indicator
50
has pressure indicia marked on an outer periphery thereof for indicating the tire pressure. However, the friction between the pressure indicator
50
and the chamber
51
is so large such that the pressure indicated by the pressure indicator
50
is not precise.
The present invention intends to provide a pressure gauge that may provide accurate tire pressure indication.
SUMMARY OF THE INVENTION
In accordance with a first aspect of the invention, a pressure gauge of a tire pump comprises:
a member adapted to be attached to the tire pump and defining a chamber therein, the chamber having a first end which is sealed by an end member, the chamber further having a second end adapted to communicate with said tire pump, a window being defined in the member, and
a pressure indicator having a tube with a head portion attached to a first end thereof and a receptacle defined in a second end thereof, indicia being provided around an outer periphery of said tube so as to be seen via said window, a spring being received in the chamber and attached between said end member and an end wall defining said receptacle, said head portion being in slidable contact with an inner periphery of said chamber, and an annular gap being defined between said tube and said inner periphery of said chamber.
Preferably, the tube has a circular outer periphery. A first rotational member is rotatably mounted to the end wall defining the receptacle of the tube. The spring includes an end securely attached to the rotational member to move therewith. The end wall defining the receptacle of the tube has a first notch defined therein. The first rotational member includes a first tip portion rotatably received in the notch. The first rotational member may include a compartment for securely receiving the end of the spring. An annular gap is defined between the first rotational member and an inner periphery of the tube.
A second rotational member is rotatably mounted to the end member. The other end of the spring is securely attached to the second rotational member to rotate therewith. The end member has a second notch defined in an end facing the tube. The second rotational member has a second tip portion rotatably received in the second notch. The second rotational member may include a compartment for securely receiving the other end of the spring.
The first end of the tube includes an engaging member extended therefrom for securely engaging with the head portion. The head portion has a slit, and the engaging member has a neck from which an enlarged head extends. The neck is securely received in the slit, and the enlarged head is retained in the head portion by engaging with an inner periphery of the head portion.
In accordance with a second aspect of the invention, a pressure gauge of a tire pump comprises:
a member adapted to be attached to the tire pump and defining a chamber therein, the chamber having a first end which is sealed by an end member, the chamber further having a second end adapted to communicate with said tire pump, a window being defined in the member and having indicia provided thereon, and
a pressure indicator having a tube with a head portion attached to a first end thereof and a receptacle defined in a second end thereof, a line being provided on an outer periphery of said tube so as to be seen via said window for indicating tire pressure, a spring being received in the chamber and attached between said end member and an end wall defining said receptacle, said head portion being in slidable contact with an inner periphery of said chamber, and an annular gap being defined between said tube and said inner periphery of said chamber.
By such an arrangement, when the pressure indicator is moved in the chamber, the only friction is happened between the head portion and the inner periphery of the chamber. The two rotational members may rotate about the two respective tip portions when the spring is compressed so that rotational effect of the spring is eliminated. Therefore, the less friction between the pressure indicator and the inner periphery of the chamber and elimination of the rotational effect of the spring increase tire pressure indication accuracy.
Further objects, advantages, and features of the present invention will become apparent from the following detailed description with appropriate reference to the accompanying drawings.
REFERENCES:
patent: 4919600 (1990-04-01), Yang
patent: 5503012 (1996-04-01), Rabizadeh
patent: 5779457 (1998-07-01), Chuang et al.
Baxley Charles E.
Pwu Jeffrey C
Walberg Teresa
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