Title of Invention

"A MECHANICAL PRESSURE GAUGE HAVING A DIGITAL OUTPUT DEVICE"

Abstract

A mechanical pressure gauge includes a digital output device which receives information from a photo detection device reading the beams passing through apertures of a fringe disk which rotates corresponding to the pressure in the Bourdon tube. Two damping devices are respectively connected the spindle of the fringe disk and the shaft of a rack which drives the spindle of the fringe disk so that the speed of the fringe disk rotates slower for convenience of detection of the photo detection device.

Full Text

FIELD OF THE INVENTION The present invention relates to a pressure gauge, and more particularly to a mechanical pressure gauge, wherein the rotational speed of the fringe disk is reduced such that the photo detecting device may detect the data precisely. BACKGROUND OF THE INVENTION A conventional mechanical pressure gauge with digital output known to applicant is disclosed in U.S. 6,530,281 which discloses a digital output device powered by a battery is connected to a detection device which detects photo type data from reading beams passing through apertures of a fringe disk. The fringe disk rotates in correspondence with the pressure of the Bousrdon tube. Nevertheless, the speed of the rotation of the fringe disk is so fast that the detection device cannot precisely detect the data reading from the beams passing through the apertures of the fringe disk. The present invention intends to provide a speed reduction device that effectively reduces the rotational speed of the fringe disk such that the detection device has enough time to detect and calculate the data and transfers the data into precise digits. SUMMARY OF THE INVENTION The present invention relates to a pressure gauge comprising a Bourdon tube which has one end connected to a driving device. The driving device has a rack connected to a shaft and a first damping device is connected to an end of the shaft. A fringe disk has a plurality of apertures defined therethrough and is connected to a toothed spindle which is engaged with the rack. A volute spring is mounted to the toothed spindle. A photo detection device has a detection member located at a side of the fringe disk and reads beams passing through the apertures of the fringe disk. A digital output device includes a circuit board is electrically connected the photo detection device. The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. BRIEF DESCRIPTION OFTHE DRAWINGS Fig. 1 is an exploded view to show the front side of the pressure gauge of the present invention; Pig. 2 is a perspective view to show the rear side of the pressure gauge of the present invention; Fig. 3 shows an exploded view to show the two damping devices and the shaft and toothed spindle in the pressure gauge of the present invention; Fig. 4 is a cross sectional view to show the first damping device of the present invention, and Fig. 5 is a cross sectional view to show the second damping device of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to Figs. 1 to 3, the pressure gauge of the present invention comprises housing in which a Bourdon tube 12 is received and the Bourdon tube 12 is connected to an input port 11 to which a pressure source to be measured is connected. One end of the Bourdon tube 12 is connected to a driving device 20 which includes a rack 21 which is connected to a shaft 22. A first damping device 13 is connected to an end of the shaft 22. A fringe disk 30 has a plurality of apertures 33 defined therethrough and is connected to a toothed spindle 31 which is connected at a center of the fringe disk 30. The rack 21 is engaged with the toothed spindle 31 so that the fringe disk 30 is rotated when the toothed spindle 31 is rotated by the rack 21. A volute spring 32 is mounted to the toothed spindle 31 so that when no pressure is entered, the toothed spindle 31 rotates back to its initial status. A second damping device 14 is connected to an end of the toothed spindle 31. A photo detection device 60 has a detection member 61 which is located at a side of the fringe disk 30 and may read beams passing through the apertures 33 of the fringe disk 30. The detection member 61 detects the beams passing through the apertures 33 of the fringe disk 30 and cannot detect the beams when the portions 34 between the two apertures 33 are in alignment with the detection member 61. By the detection, the photo detection device 60 calculates the speed and the related data, both of which are transferred into pressure in digits form which is displayed in a digital output device 50. The digital output device SO includes a circuit board 40 and is electrically connected to the photo detection device 60. The digital output device 50 being powered by a battery 41 in the housing. As shown in Figs. 4 and 5, the first damping device 13 includes a first cup and the shaft 22 has an end thereof extending through a close end of the first cup. A damp disk 23 is connected to the end of the shaft 22 and damping oil 15 is filled in the first cup. A cover 16 seals an open end of the first cup. Similarly, the second damping device 14 includes a second cup and the toothed spindle 31 has an end thereof extending through a close end of the second cup. Another damp disk 35 is connected to the end of the toothed spindle 31 and damping oil 15 is filled in the second cup. A cover 17 seals an open end of the second cup. By the two damping devices 13 and 14, the speed of the rotation of the fringe disk 30 becomes slower so that the detection member 61 has enough time to precisely read and calculate the data from the fringe disk 30. While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention. I claim: 1. A pressure gauge comprising: a Bourdon tube (12) characterized in that connected to an input port (11) and one end of the Bourdon tube (12) connected to a driving device (20), the driving device having a rack (12) which is connected to a shaft (22), a first damping device (13) connected to an end of the shaft, the first damping device having a first cup and the shaft (22) having an end thereof extending through a close end of the first cup, a damp disk (23) connected to the end of the shaft (22) and damping oil (15) filled in the first cup, a cover (16) sealing an open end of the first cup; a fringe disk (30) having a plurality of apertures (33) defined therethrough and connected to a toothed spindle (31), a volute spring (32) mounted to the toothed spindle (31), the rack (21) engaged with the toothed spindle (31); a photo detection device (60) having a detection member (61) located at a side of the fringe disk (30) and adapted to read beams passing through the apertures (33) of the fringe disk, and a digital output device (50) having a circuit board (40) and electrically connected to the photo detection device (60). 2. The pressure gauge as claimed in claim 1, wherein a second damping device (14) is connected to an end of the toothed spindle (31), the second damping device (14) having a second cup and the toothed spindle (31) having an end thereof extending through a close end of the second cup, a damp disk (35) connected to the end of the toothed spindle (31) and damping oil (15) filled in the second cup, a cover (17) sealing an open end of the second cup. 3. A pressure gauge comprising: a Bourdon tube (12) characterized in that connected to an input port (11) and one end of the Bourdon tube (12) connected to a driving device, the driving device (20) having a rack (21) which is connected to a shaft (22); a fringe disk (30) having a plurality of apertures (33) defined therethrough and connected to a toothed spindle (31), a volute spring (32) mounted to the toothed spindle (31), the rack (21) engaged with the toothed spindle (31), a second damping device (14) connected to an end of the toothed spindle (31), the second damping device (14) having a second cup and the toothed spindle (31) having an end thereof extending through a close end of the second cup, a damp disk (35) connected to the end of the toothed spindle (31) and damping oil (15) filled in the second cup, a cover (17) sealing an open end of the second cup; a photo detection device (60) having a detection member (61) located at a side of the fringe disk (30) and adapted to read beams passing through the apertures (33) of the fringe disk (30), and a digital output device (50) having a circuit board (40) and electrically connected to the photo detection device (60).

Documents:

311-del-2004-abstract.pdf

311-del-2004-claims.pdf

311-del-2004-complete specification (granted).pdf

311-del-2004-correspondence-others.pdf

311-del-2004-correspondence-po.pdf

311-del-2004-description (complete).pdf

311-del-2004-drawings.pdf

311-DEL-2004-Form-1.pdf

311-del-2004-form-19.pdf

311-del-2004-form-2.pdf

311-del-2004-form-26.pdf

311-del-2004-form-3.pdf

311-del-2004-form-5.pdf

311-DEL-2004-Petition-137.pdf