Pressure venting instrument casing assembly

Claim 2

An instrument casing assembly comprising: a. a generally cup-shaped shell-like case; b. an annular ledge radially extending interior of said case; c. an annular gasket of resilient material generally overlying said ledge; d. a crystal capable of being flexed and received in the front end of said case and having an axially extending ridge about its periphery engaging against said gasket; and e. case means extending integral of said case effecting bezelless engagement against spaced front portions of said crystal at predetermined spaced locations about the crystal periphery to place the crystal in compressing relation against said gasket and form a seal engagement thereabout, said seal engagement being effective in the absence of an overpressure within said case to maintain a generally dusttight seal thereabout and being effective in response to an overpressure within said case to release said seal engagement at crystal areas intermediate said locations at which saId crystal is engaged by said case means.

Claim 3

A casing assembly as in claim 1 which said case includes a rear portion and relatively larger diameter front portion in which to receive said crystal, and said ledge comprises a radially extending wall of said case connecting said front and rear case portions.

Claim 4

A casing assembly as in claim 1 in which an annular clearance is provided between the peripheral exterior of said crystal and the interior case wall thereat, said clearance being sufficient in response to an internal overpressure to permit outward flexing of said crystal at said intermediate areas.

Claim 5

A casing assembly as in claim 3 in which a dial plate is secured between said gasket and said ledge.

Claim 6

A casing assembly as in claim 3 in which said crystal ridge includes an integral annular flange extending radially outward and frontward extending projections on said flange defining said predetermined spaced locations at which to receive said bezelless engaging case means.

Claim 7

A casing assembly as in claim 5 in which said case means is crimped against said projections to effect engagement against said crystal.

Claim 8

A casing assembly as in claim 5 in which the engaging surfaces between said flange and gasket divide a force applied axially from said case against said crystal into axial and radial components.

Claim 9

A casing assembly as in claim 7 in which said gasket engaging flange surface at least partially includes an annular bevel sloping frontward towards its periphery.

Claim 10

A casing assembly as in claim 8 in which said gasket is wedge shaped in cross section and provides an engaging surface which is generally parallel to said bevel surface.

Claim 11

An instrument casing assembly comprising: a. a generally cup-shaped shell-like case; b. an annular ledge radially extending interior of said case; c. an annular gasket of resilient material generally overlying said ledge, said gasket having an engaging surface which at least partially includes an annular bevel sloping frontward towards its periphery to divide an axially applied force thereagainst into axial and radial components; d. a crystal capable of being flexed and received in the front end of said case peripherally spaced therefrom to define an annular clearance therebetween and having an axially extending ridge about its periphery engaging against the engaging surface of said gasket, said ridge including an integral annular flange extending radially outward and having frontward extending projections thereon; and e. means on said case engaging the flange projections of said crystal to axially place the crystal in compressing relation against said gasket and form a seal engagement thereabout, said seal engagement being effective in the absence of an overpressure within said case to maintain a generally dusttight seal thereabout and being effective in response to an overpressure within said case to release said seal engagement at crystal areas intermediate said projections at which said crystal is engaged by said case means to permit said intermediate crystal areas to flex outwardly into said clearance.

Claim 12

An instrument casing assembly comprising: a. a generally cup-shaped shell-like case; b. an annular ledge radially extending interior of said case; c. an annular gasket of resilient material generally overlying said ledge, said gasket having an engaging surface which at least partially includes an annular bevel sloping frontward towards its periphery to divide an axially applied force thereagainst into axial and radial components; d. a crystal capable of being flexed and received in the front end of said case peripherally spaced therefrom to define an annular clearance therebetween and having an axially extending ridge about its periphery engaging against the engaging surface of said gasket, said ridge including an integral annular flange extending radially outward and having frontward extending projections thereon; and e. means on said case engaging the flange projections of said crystal to axially place the crystal in compressing relation against said gasket and form a seal engagement thereabout, said seal engagement being effective in the absence of an overpressure within said case to maintain a generally dusttight seal thereabout and being effective in response to an overpressure within said case to release said seal engagement at crystal areas intermediate said projections at which said crystal is engaged by said case means to permit said intermediate crystal areas to flex outwardly into said clearance.

Claim 13

A casing assembly as in claim 10 in which said gasket is wedge shaped in cross section and provides a second engaging surface which is generally parallel to said bevel engaging surface.