Pressure gauge having interchangeable indicator components and positive piston stop

Claim 2

A pressure gauge comprising: an elongate body member having a bore extending axially therethrough; a piston slidably mounted within said bore for movement between a fully retracted position and advanced positions wherein portions of the piSton project beyond the body member from one end of the bore; a compression spring within said bore normally urging said piston to a fully retracted position; means securely though releasably closing the other end of said bore for retaining the piston and spring within the bore, said means having a passageway therethrough in open communication with the interior of the bore at said other end thereof; that end of the body member adjacent the said one end of the bore terminating in a transverse end-face circumscribed by a continuous, annular, tab-receptive groove; a calibrated indicator securely though releasably mounted on said body member at said end face and projecting longitudinally outward from said one end of the bore; and said indicator including a base portion having a plurality of resilient, axially projecting lock-tabs in snap-detented relationship with said groove for mounting the indicator to the body member.

Claim 3

A pressure gauge as called for in claim 1, wherein said last mentioned means comprises a plug having an inner transverse face against which an end of the piston abuts when in a fully retracted position.

Claim 4

A pressure gauge as called for in claim 2, wherein that end of the piston which abuts the plug terminates in an outwardly projecting flange having an upper, spring-abutment face and a lower, substantially flat, transverse end-face.

Claim 5

A pressure gauge as called for in claim 3, wherein a portion of the bore is of reduced diameter defining a shoulder therein spaced inwardly from the said one end thereof; a self-lubricating sealing member within the bore in abutting relationship with the periphery of the piston, providing a fluid-tight seal between the piston and body member; a spring keeper within the bore in abutting relationship with said sealing member, opposite ends of said spring abutting against the keeper and the spring abutment face of the piston, respectively, urging the piston to a fully retracted position.

Claim 6

A pressure gauge as called for in claim 4, wherein the piston includes a shoulder intermediate its length adapted to abut the spring keeper for limiting the fully advanced position of the piston relative to the body member.

Claim 7

A pressure gauge as called for in claim 1, including a transparent housing secured to, carried by and substantially encasing the indicator.

Claim 8

A pressure gauge as called for in claim 6, including sealing means interposed between the body member, the indicator and the housing to effect a fluid-tight sealing relationship therebetween.

Claim 9

A pressure gauge comprising: an elongate body member having a bore extending axially therethrough, a portion of said bore being of reduced diameter, defining a shoulder in said bore spaced inwardly from one end thereof; a piston slidably mounted within said bore for movement between a fully retracted position and advanced positions wherein one end of the piston projects beyond the body member from said one end of the bore, said piston including a shoulder intermediate the length thereof, and an outwardly projecting flange at the other end thereof having an upper, substantially flat, annular face and a lower, substantially flat end-face; a self-lubricating sealing member within the bore in abutting relationship with said shoulder and in circumscribing contacting relationship with the periphery of said piston, providing a fluid-tight seal between the piston and the body member; a spring keeper within the bore and in abutting relationship with said sealing member, including an annular face adapted to abut the shoulder of the piston, limiting advancement thereof relative to the body member; a compression spring within said bore, opposite ends of which abut the spring keeper and the upper, annular face of the piston for normally urging said piston to a fully retracted position; a plug in snug, slip-fit relationship with the said other end of the bore, securely though releasably closing said other end of the borE for retaining the piston, the spring and keeper, and the sealing member within said bore, the inner end of said plug terminating in a transverse face against which the flat end-face of the piston abuts when in a fully retracted position, the plug including an axial aperture therethrough in open communication with the interior of the bore at the said other end thereof; the end of the body member adjacent the said one end of the bore terminating in a transverse end-face circumscribed by a continuous, annular tab-receptive groove; a calibrated indicator projecting longitudinally outward from the said one end of the bore, the indicating means including a base portion having a plurality of resilient, axially projecting lock tabs in snap-detented relationship with said groove for mounting the indicator to the body member; a transparent housing secured to, carried by and substantially encasing said indicator; and sealing means interposed between the body member, the indicator and the transparent housing to effect a fluid-tight sealing relationship therebetween.

Claim 10

A pressure gauge comprising: an elongate body member having a bore extending axially therethrough, a portion of said bore being of reduced diameter, defining a shoulder in said bore spaced inwardly from one end thereof; a piston slidably mounted within said bore for movement between a fully retracted position and advanced positions wherein one end of the piston projects beyond the body member from said one end of the bore, said piston including a shoulder intermediate the length thereof, and an outwardly projecting flange at the other end thereof having an upper, substantially flat, annular face and a lower, substantially flat end-face; a self-lubricating sealing member within the bore in abutting relationship with said shoulder and in circumscribing contacting relationship with the periphery of said piston, providing a fluid-tight seal between the piston and the body member; a spring keeper within the bore and in abutting relationship with said sealing member, including an annular face adapted to abut the shoulder of the piston, limiting advancement thereof relative to the body member; a compression spring within said bore, opposite ends of which abut the spring keeper and the upper, annular face of the piston for normally urging said piston to a fully retracted position; a plug in snug, slip-fit relationship with the said other end of the bore, securely though releasably closing said other end of the borE for retaining the piston, the spring and keeper, and the sealing member within said bore, the inner end of said plug terminating in a transverse face against which the flat end-face of the piston abuts when in a fully retracted position, the plug including an axial aperture therethrough in open communication with the interior of the bore at the said other end thereof; the end of the body member adjacent the said one end of the bore terminating in a transverse end-face circumscribed by a continuous, annular tab-receptive groove; a calibrated indicator projecting longitudinally outward from the said one end of the bore, the indicating means including a base portion having a plurality of resilient, axially projecting lock tabs in snap-detented relationship with said groove for mounting the indicator to the body member; a transparent housing secured to, carried by and substantially encasing said indicator; and sealing means interposed between the body member, the indicator and the transparent housing to effect a fluid-tight sealing relationship therebetween.