Patent Publication Number: US-2023152176-A1

Title: Pressure Gauge for Air Pump

Description:
BACKGROUND 
     The present invention relates to a pressure gauge and, more particular, to a pointer pressure gauge for a compact air pump. 
     Conventional portable air pumps usually have a compact appearance in order to be convenient to carry. Thus, the portable air pump will inevitably lose the convenience of pumping operations in order to have a compact appearance. For example, the portable pump usually does not provide a pressure gauge for measuring and displaying the pressure value. In addition, if the portable pump provides a pressure gauge, the elements of the pressure gauge must have a small size, and how to make the pressure gauge with smaller elements can accurately measure the pressure value has become a problem that needs to be improved. 
     SUMMARY 
     An objective of the present invention is to provide a pressure gauge, which includes a housing arranged in a containing recess of an air pump, a driving member movably arranged in the housing, a biasing member configured to bias the driving member toward the housing, a driven member configured to be driven to rotate by the driving member, a pointer needle connected with the driven member, a scale plate disposed between the driven member and the pointer needle, and a guiding member arranged between the housing and the driving member and configured to contact at least one of the housing and the driving member to remain the driving member moving relative to the housing in a straight direction. 
     In an embodiment, the housing has a sliding hole and an air inlet hole communicating with the sliding hole. The air inlet hole permits the compressed air from the air pump to enter the sliding hole and to propel the driving member. The driving member has a sliding portion movably arranged in the sliding hole, and a driving portion formed on an outer periphery of the sliding portion. The sliding portion is configured to be propelled by the compressed air entering the sliding hole from the air inlet hole to move relative to the sliding hole along a reference axis. The driving portion connects with the driven member to drive the driven member to rotate. 
     In an embodiment, the housing further has a notch formed an outer periphery thereof and communicating with the sliding hole. The driving portion has an extending section extended from the outer periphery of the sliding portion, and a gear rack formed from the extending section and extended along the straight direction parallel to the reference axis. The extending section extends through out of the sliding hole via the notch. The gear rack is perpendicular to the extending section and separated from the outer periphery of the sliding portion by a gap formed between the sliding portion and the gear rack. The driven member has an annular teeth portion formed around an outer periphery thereof and meshed with the gear rack. The gear rack corresponds the sliding portion moving relative to the sliding hole to move along the straight direction parallel to the reference axis to drive the driven member to rotate. 
     In an embodiment, the guiding member is integrally formed at an end of the gear rack opposite to the extending section and constantly abuts against the outer periphery of the housing. 
     In an embodiment, the guiding member has an arc face abutting against the outer periphery of the housing. 
     In another embodiment, the guiding member is integrally formed on the outer periphery of the housing and constantly abuts against the gear rack. 
     In another embodiment, the guiding member has an arc face abutting against the gear rack. 
     In an embodiment, the biasing member has a first end elastically abutting against the containing recess, and a second end elastically abutting against the driving member. 
     The present invention will become clearer in light of the following detailed description of illustrative embodiments of this invention described in connection with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an exploded, perspective view of a pressure gauge of a first embodiment according to the present invention. 
         FIGS.  2  and  3    are cross sectional views of the pressure gauge of the first embodiment according to the present invention. 
         FIG.  4    is a cross sectional views of a pressure gauge of the second embodiment according to the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS.  1 - 3    show a pressure gauge  1  for an air pump  2  of a first embodiment according to the present invention. The pressure gauge  1  is adapted to be mounted in a containing recess  21  of an air pump  2 . The air pump  2  is mentioned in this embodiment may be a portable air pump, and the containing recess  21  is formed on a head portion of the air pump  2 . The pressure gauge  1  includes a housing  11  arranged in the containing recess  21  and permitting the compressed air from the air pump  2  to enter therein, a driving member  12  movably arranged in the housing  11  and configured to be propelled by the compressed air from the air pump  2 , a biasing member  13  configured to bias the driving member  12  toward the housing  11 , a driven member  14  configured to be driven to rotate by the driving member  12 , a pointer needle  15  connected with the driven member  14 , a scale plate  16  disposed between the driven member  14  and the pointer needle  15 , and a guiding member  17  arranged between the housing  11  and the driving member  12 . The guiding member  17  is configured to contact at least one of the housing  11  and the driving member  12  to remain the driving member  12  moving relative to the housing  11  in a straight direction to accurately measure and display the pressure value. 
     The biasing member  13  has a first end elastically abutting against the containing recess  21 , and a second end elastically abutting against the driving member  12 . Thus, the biasing member  13  may be a spring. 
     Further, the housing  11  has a sliding hole  111  and an air inlet hole  112  communicating with the sliding hole  111 . The air inlet hole  112  permits the compressed air from the air pump  2  to enter the sliding hole  111  and to propel the driving member  12 . The driving member  12  has a sliding portion  121  movably arranged in the sliding hole  111 , and a driving portion  122  formed on an outer periphery of the sliding portion  121 . The sliding portion  121  is configured to be propelled by the compressed air entering the sliding hole  111  from the air inlet hole  112  to move relative to the sliding hole  111  along a reference axis  22 . The driving portion  122  connects with the driven member  14  to drive the driven member  14  to rotate. 
     Furthermore, the housing  11  has a notch  113  formed an outer periphery thereof and communicating with the sliding hole  111 . The driving portion  122  has an extending section  123  extended from the outer periphery of the sliding portion  121 , and a gear rack  124  formed from the extending section  123  and extended along the straight direction parallel to the reference axis  22 . The extending section  123  extends through out of the sliding hole  111  via the notch  113 . The gear rack  124  is perpendicular to the extending section  123  and separated from the outer periphery of the sliding portion  121  by a gap  125  formed between the sliding portion  121  and the gear rack  124 . The driven member  14  has an annular teeth portion  141  formed around an outer periphery thereof and meshed with the gear rack  124 . The gear rack  124  corresponds the sliding portion  121  moving relative to the sliding hole  111  to move along the straight direction parallel to the reference axis  22  to drive the driven member  14  to rotate, so that the driven member  14  actuates the pointer needle  15  to indicate the pressure value on the scale plate  16 . 
     In the embodiment, the guiding member  17  is integrally formed at an end of the gear rack  124  opposite to the extending section  123  and constantly abuts against the outer periphery of the housing  11 . Thus, the driving member  12  and the guiding member  17  may be integrally formed by plastic injection, and the guiding member  17  abuts against the outer periphery of the housing  11  to prevent the inaccurate pressure value since the gear rack  124  is deviated from the extending section  123  due to excessive length. 
     Moreover, the guiding member  17  has an arc face  171  abutting against the outer periphery of the housing  11  to reduce the friction between the guiding member  17  and the outer periphery of the housing  11 . 
       FIG.  4    is a cross sectional views of a pressure gauge of the second embodiment according to the present invention. The second embedment is substantially the same as the first embodiment. The main differences are that the guiding member  17   a  is integrally formed on the outer periphery of the housing  11   a  and constantly abuts against the gear rack  124 , and the guiding member  17   a  has an arc face  171   a  abutting against the gear rack  124  to reduce the friction between the guiding member  17   a  and the gear rack  124 . 
     Although specific embodiments have been illustrated and described, numerous modifications and variations are still possible without departing from the scope of the invention. The scope of the invention is limited by the accompanying claims.