BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to air compressors and more particularly, to a digit button-operated air compressor output control structure.
2. Description of the Related Art
FIG. 1 illustrates a regular air compressor 1, which comprises a shielding shell 2 and a tank 3. The shielding shell 2 has mounted therein parts for generating compressed air such as motor, fan, and etc. The tank 3 is for accumulation of compressed air. When using the air compressor 1, the air outlet 4 of the air compressor 1 is connected to an external air tool (not shown) so that compressed air goes out of the air compressor 1 through the air outlet 4 to the external air tool for driving a movable part of the external air tool. The air compressor 1 has a control knob 5 for regulating the pressure of air that goes out of the air outlet 4, and a pressure meter 6 connected between the control knob 5 and the air outlet 4 for measuring the pressure of output air. The use of this structure of air compressor has drawbacks. When regulating the output pressure, the user must operate the control knob 5 and at the same time watch the indication of the pressure meter 6 till the accurate output pressure is in presence. The user shall have to spend a lot of time in regulating the desired output pressure. Further, because the control knob 5 is exposed to the outside of the shielding shell 2, it may be rotated or hit by a nearby worker accidentally, causing damage to the air tool or injury to workers.
SUMMARY OF THE INVENTION
The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a digit button-operated air compressor output control structure, which controls the output of compressed air from an air compressor by means of a digital control panel and an air pressure regulating structure so that the user can set the desired output air pressure quickly and control the output air pressure stably.
It is another object of the present invention to provide a digit button-operated air compressor output control structure, which is equipped with pressure sensors for accurate air pressure output control.
To achieve these and other objects of the present invention, the digit button-operated air compressor output control structure is for controlling output of compressed air from an air compressor, comprising a main body, an exhaust valve, an intake valve assembly, a first pressure sensor, a second pressure sensor, and a control panel. The main body is fixedly fastened to the air compressor, comprising an air inlet connected to the air compressor for guiding in compressed air from the air compressor, an air outlet for guiding out compressed air, a main air chamber, a first air passage in communication between the air inlet and the main air chamber, and a second air passage in communication between the air inlet and the main air chamber. The exhaust valve is movable in the main air chamber and divides the main air chamber into a first air chamber and a second air chamber. The first air chamber is in communication with the first air passage and the air outlet. The second air chamber is in communication with the second air passage. The intake valve assembly is mounted in the second air passage, and adapted to regulate the flow rate of compressed air from the air compressor into the second air chamber. The first pressure sensor is mounted in the second air passage between the air inlet and the intake valve assembly, and adapted to detect the air pressure in the second air passage and to output a first signal indicative of the detected air pressure. The second pressure sensor is mounted in between the intake valve assembly and the second air chamber, and adapted to detect the air pressure in between the intake valve assembly and the second air chamber and to output a second signal indicative of the detected air pressure. The control panel comprises a circuit board electrically connected to the intake valve assembly and the first pressure sensor and the second pressure sensor and adapted to convert the first signal from the first pressure sensor and the second signal from the second pressure sensor into respective digital signals for display through display screen means, a set of digit control keys electrically connected to the circuit board for setting the control of the intake valve assembly in regulating the flow rate of compressed air from the air compressor into the second receiving chamber, and display screen means electrically connected to the circuit board for displaying the digital signals produced by the circuit board.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of a conventional air compressor.
FIG. 2 is an elevational view of a digit button-operated air compressor output control structure in accordance with the present invention.
FIG. 3 is an exploded view of the digit button-operated air compressor output control structure in accordance with the present invention.
FIG. 4 is a schematic side view of a part of the present invention, showing the structure of the connecting member of the main body.
FIG. 5 is a schematic side view of a part of the present invention, showing the arrangement of the control panel and the flow guide.
FIG. 6 is a schematic bottom view of a part of the present invention, showing the arrangement of the flow guide and the control panel.
FIG. 7 is a schematic bottom view of a part of the present invention, showing the arrangement of the flow guide and the valve holder.
FIG. 8 is a schematic drawing of a part of the present invention, showing the flowing direction of compressed air in the flow guide and the connecting member.
FIG. 9 is a schematic sectional view of a part of the present invention, showing the arrangement of the first regulating valve and the second regulating valve in the valve holder.
FIG. 10 is a top view of the touch panel according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 2-10, a digit button-operated air compressor output control structure 10 in accordance with the present invention is connected between an air compressor (not shown) and an air tool (not shown) for controlling output of compressed air from the air compressor to the air tool. The digit button-operated air compressor output control structure 10 comprises a main body 12, an exhaust valve 14, an intake valve assembly 16, a control panel 18, a first pressure sensor 20, and a second pressure sensor 22.
The main body 12 is comprised of a connecting member 121 and a flow guide 122. The connecting member 121 is fastened to one side of the flow guide 122. The connecting member 121 and the flow guide 122 are affixed to the air compressor.
The connecting member 121 is formed of a manifold, having an air inlet 121a, an air outlet 121b, and a first groove 121c. The groove 121c is formed on one side of the connecting member 121 that is fixedly fastened to the flow guide 122 (see FIG. 4). The air inlet 121a is in communication with a first main air passage Al and a first sub air passage A2 that are defined inside the connecting member 121. The first main air passage A1 is in communication with the first groove 121c. The first sub air passage A2 is in communication with the first main air passage Al and the flow guide 122. The internal compressed air of the air compressor goes through the first main air passage A1 into the first groove 121c and then through the first sub air passage A2 into the flow guide 122. The air outlet 121b is in communication with the first groove 121c for guiding compressed air from the first groove 121c to the air tool.
The flow guide 122 has a second groove 122a formed on its one side corresponding to the first groove 121c, as shown in FIG. 6, a front air passage A3, a third groove 122b and an opening 122c on its back side, and a first receiving hole 122d and a second receiving hole 122e formed on the front side and disposed in communication with the third groove 122b and the second groove 122a respectively. The front air passage A3 is in communication with the first sub air passage A2 of the connecting member 121 and the third groove 122b of the flow guide 122 for guiding compressed air out of the connecting member 121 into the flow guide 122. The opening 122c is formed on the peripheral wall of the second groove 122a. The first receiving hole 122d and the second receiving hole 122e accommodate the first pressure sensor 20 and the second pressure sensor 22 respectively.
The exhaust valve 14 is comprised of a plunger 141, a valve sleeve 142, a valve plug 143, and an elastic member 144. As shown in FIG. 8, the plunger 141 is mounted in the first groove 121c, defining with the first groove 121c a first receiving chamber 12a and also defining with the second groove 122a a second receiving chamber 12b. The first receiving chamber 12a and the second receiving chamber 12b constitute a chamber 123. When the air pressure in the first receiving chamber 12a and the air pressure in the second receiving chamber 12b are not equal, the plunger 141 will be moved in the first receiving chamber 12a. Further, the plunger 141 has a pin 141a inserted into the first receiving chamber 12a. The valve sleeve 142 has a small diameter section 142a, a big diameter section 1242b, and an axial hole 142c. The small diameter section 142a is set in the junction between the first groove 121c and the first main air passage A1. The small diameter section 142a has two side holes 142d in communication with the axial hole 142c. The big diameter section 142b has radial grooves 142e. The side holes 142d, the axial hole 142 and the radial grooves 142e constitute an exhaust air passage A4, as shown in FIG. 4, for guiding compressed air from the first main air passage A1 through the exhaust air passage A4 into the first receiving chamber 12a and then out of the air outlet 121b. The valve plug 143 is a rubber member inserted into the axial hole 142c to seal the two side holes 142d. The elastic member 144 according to this embodiment is a spring, having one end stopped against the inside wall of the connecting member 121 and the other end stopped against the valve plug 143. Therefore, the elastic member 144 supports the valve plug 143 in the position where the valve plug 143 seals the side holes 142d to block the exhaust air passage A4. When the plunger 141 is forced by compressed air to move toward the valve sleeve 142, the pin 141a of the plunger 141 is inserted into the axial hole 142c to push the valve plug 143 away from the side holes 142d, thereby opening the exhaust air passage A4.
The intake valve assembly 16 is affixed to the back side of the flow guide 122, which is provided with the third groove 122b and the opening 122c. The intake valve assembly 16 is comprised of a valve holder 161, a first regulating valve 162, and a second regulating valve 163. The first regulating valve 162 and the second regulating valve 163 according to this embodiment are electromagnetic valves.
As shown in FIGS. 7-9, the valve holder 161 is fixedly connected to the flow guide 122, having a first air chamber 161a, a second air chamber 161b, a first through hole 161c in communication between the first air chamber 161a and the third groove 122b (see FIG. 7), and a second through hole 161d in communication between the first air chamber 161a and the opening 122c. The first air chamber 161a constitutes with the first through hole 161c and the second through hole 161d a middle air passage A5. As shown in FIG. 7, the middle air passage A5 is in communication with the third groove 122b and the opening 122c. As shown in FIG. 8, the first sub air passage A2 and the front air passage A3 constitute with the middle air passage A5 a second air passage A6. The second air passage A6 is in communication with the air inlet 121a and the second receiving chamber 12b. The valve holder 161 further has a third through hole 161e in communication between the second air chamber 161b and the opening 122c, and a fourth through hole 161f in communication between the second air chamber 161b and the outside space. The flowing direction of compressed air among the aforesaid component parts will be described further.
As shown in FIG. 9, the first regulating valve 162 is fixedly fastened to the valve holder 161 and electrically connected to the control panel 18 by an electric circuit (not shown). The first regulating valve 161 has a first stop member 162a corresponding to the first air chamber 161a. The first stop member 162a is movable in the first air chamber 161a subject to the control of the control panel 18, thereby changing the volume of the first air chamber 161a to regulate the flow rate of compressed air that goes out of the first air chamber 161a through the second through hole 161d and the opening 122a into the second receiving chamber 12b.
The second regulating valve 163 is fixedly fastened to the valve holder 161 and electrically connected to the control panel 18 by an electric circuit (not shown). The second regulating valve 163 has a second stop member 163a corresponding to the second air chamber 161b. The second stop member 163a is movable in the second air chamber 161b subject to the control of the control panel 18, thereby changing the volume of the second air chamber 161b to regulate the flow rate of compressed air that goes out of the second air chamber 161b through the fourth through hole 161f to the outside.
As shown in FIG. 3, the control panel 18 is fixedly mounted on one side of the flow guide 122, comprised of a circuit board 181 and a touch panel 182.
The circuit board 181 carries the first pressure sensor 20 and the second pressure sensor 22 on its one side facing the flow guide 122. As shown in FIG. 6, the first pressure sensor 20 is inserted through the first receiving hole 122d into the third groove 122b to detect air pressure in the front air passage A3, and to output a first signal to the circuit board 181 indicative of the detected air pressure. The second pressure sensor 22 is inserted through the second receiving hole 122e into the second groove 122a to detect air pressure in the second receiving chamber 12b, and to output a second signal to the circuit board 181 indicative of the detected air pressure. Further, a battery 24 is electrically connected to the circuit board 181 to work as standby power supply for the circuit board 181. The circuit board 181 further has mounted on its one side that is bonded to the touch panel 182 a display screen 181a, a set of digit control key switches 181b, four first light sources 181c, a unit switching key 181d, an enter key 181e, a clear key 181f, a safety key 181g, and a second light source 181h. The display screen 181a has its upper part for indicating the air pressure detected by the first pressure sensor 20, and its lower part for indicating the air pressure detected by the second pressure sensor 22. The functions of the other keys and light sources of the circuit board 181 will be described with the touch panel 182 hereinafter.
The touch panel 182 according to this embodiment is a plastic membrane. As shown in FIG. 10, the touch panel 182 is bonded to the side of the circuit board 181 carrying the digit control key switches 181b, having a window 182a corresponding to the display screen 181a, a set of digits 182b corresponding to the digit control key switches 181b, the signs of “PSI” 182c, “BAR” 182d, “KPA” 182e and “KGP” 182f corresponding to the four first light sources 181c, the sign of “BAT” 182g corresponding to the second light source 181h, the sign of “Unit” 182h corresponding to the unit switching key 181d, the sign of “Enter” 182i corresponding to the enter key 181e, the sign of “C” 182j corresponding to the clear key 181f, and the sigh of “Luck” corresponding to the safety key 181g. By means of touching the touch panel 182, the user can switch the respective keys of the circuit board 181.
The digit control key switches 181b allow the user to set the output air pressure of the air compressor to the air tool. After setting of the desired output air pressure, press the sign of “Enter” 182i to drive the circuit board 181, causing the circuit board 181 to control the position of the first stop member 162a of the first regulating valve 162. Further, when wishing to change the setting of the desired output air pressure, press the sign “C” 182j to switch the clear key 181f, thereby zeroing the reading in the lower part of the display screen 181a for resetting. Further, clicking the sign of “Unit” 182h each time, one of the first light sources 181c is switched on and the other first light sources 181c are switched off, indicating the corresponding sigh on the touch panel 182. For example, when the first light source 181c corresponding to the sign of “PSI” 182c is switched on, the reading shown in the window 182a is based on the air pressure unit PSI. When pressing the sign “Luck” 182k, the unit switching key 181d, the enter key 181e, the clear key 181f, and the digit control key switches 181b are switched between the enable mode and the disable mode, preventing triggering the touch panel 182 accidentally. Further, when the power level of the battery 24 drops below a predetermined value, the second light source 181h is switched on to light up the sign “BAT” 182g, advising the user to replace battery.
After understanding of the component parts of the digit button-operated air compressor output control structure 10 and their relationship, the operation of the present invention is described hereinafter.
If the user does not set the output air pressure, the first stop member 162a of the first regulating valve 162 is stopped at the second through hole 161d of the valve holder 161, blocking compressed air in the third groove 122b and prohibiting compressed air from entering the second receiving chamber 12b, and therefore the first pressure sensor 20 detects the tank pressure of the air compressor and outputs a corresponding first signal to the circuit board 181. The circuit board 181 converts the first signal into a digital signal for output through the upper part of the display screen 181a. At the same time, the second pressure sensor 22 detects the air pressure of the second receiving chamber 12b and outputs a corresponding second signal to the circuit board 181. The circuit board 181 converts the second signal into a digital signal for output through the lower part of the display screen 181a. Because no compressed air goes into the second receiving chamber 12b at this time, the indication on the lower part of the display screen 181a remains unchanged.
When the user operated the digit control key switches 181b and pressed the sign “Enter” 182i as shown in FIG. 9, the circuit board 181 is driven to move the first stop member 162a relative to the second through hole 161d to change the volume of the first air chamber 161a, regulating the flow rate of compressed air into the second receiving chamber 12b subject to the set output air pressure. At this time, the plunger 141 is moved by compressed air to change the volume of the first receiving chamber 12b, and the pin 141a of the plunger 141 pushes the valve plug 143 away from the side holes 142d of the valve sleeve 142 against the elastic member 144 to open the exhaust air passage A4, allowing compressed air to go from the first air passage A1 out of the exhaust air passage A4. Thus, the user can start other works immediately after setting of the desired output air pressure, saving much time and labor. Further, the safety key design of the touch panel prevents an accidental triggering. When compared to the conventional control knob design, the invention is safe in use.
Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.
Patent Application
20080232980
