Filter assembly featuring displaceable filter head plunger for locking into filter cartridge detent

A filter cartridge and head unit comprising:

• a head having an inlet passage and an outlet passage;
• a cartridge having a cavity for filter material;
• securing means for twisting the cartridge onto the head;
• and
• locking means for preventing untwisting of the cartridge;
• said locking means comprising:
• a plunger;
• and
• a detent for receiving the plunger;
• wherein the plunger is supported by the head, and has an axis, and is axially displaceable from an unlocked position to a locked position;
• and
• wherein the plunger has a spring means engaging the head and urging the plunger to the locked position, and
• wherein the detent is disposed in a top wall surface of the cartridge and is coaxial with the plunger in the locked position when aligned therewith;
• and
• wherein the plunger has an extension extending radially outwardly therefrom for finger operation of the plunger;
• and
• wherein the head has a hole disposed along the axis of the plunger and has a retainer ring received in the hole coaxially therewith for guiding the plunger, and has a slot for guiding the extension.

A filter unit for filtering a fluid comprising:

• a head for mounting on a support, the head having an inlet port with an inlet passage and an outlet port with an outlet passage;
• a twist-on cartridge having a cavity for containing a filtering material for filtering the fluid, the cartridge being connected to the inlet passage and to the outlet passage for filtering the fluid through the filtering material;
• securing means for connecting the cartridge to the head, the securing means having a pair of diametrically opposite tab receptacles, each tab receptacle having a cam surface, and each tab receptacle being fixedly attached to the head, and further having a pair of diametrically opposite tabs, each being fixedly attached to the cartridge;
• and
• lock means for preventing untwisting of the cartridge from the head, wherein the lock means comprises:
• a plunger being disposed in a hole in the head in a peripheral direction about an axis of symmetry of the head and midway between the tab receptacles on the head, the plunger having a helical spring which urges the plunger towards a locked position for engagement, and also having an extension disposed in a slot in the head, said extension having a finger tab for lifting the plunger to an unlocked position;
• and
• at least one detent for receiving the plunger in the locked position, said at least one detent being disposed in the cartridge in a peripheral direction about an axis of symmetry of the cartridge and midway between the tabs on the cartridge.

A filter unit comprising:

• a head having securing means;
• a twist-on hollow cartridge secured thereto;
• and
• lock means comprising:
• a spring driven plunger supported by the head;
• and
• at least one detent disposed in a top wall outer surface of the cartridge, whereby inadvertent disengagement of the cartridge from the head is prevented by engagement of the plunger and the detent in a locked position.

A head unit for a filter cartridge comprising:

• an inlet passage and an outlet passage;
• securing means to enable twisting the cartridge onto the
• head;
• and
• locking means comprising:
• a plunger adapted to be received in a detent wherein the plunger is supported by the head, and has an axis, and is axially displaceable from an unlocked position to a locked position, and
• wherein the plunger has a spring means engaging the head and urging the plunger to the locked position, and
• wherein the plunger has an extension extending radially outwardly therefrom for finger operation of the plunger, and
• wherein the head has a hole disposed along the axis of the plunger and has a retainer ring received in the hole coaxially therewith for guiding the plunger, and has a slot for guiding the extension.

A head unit for a filter cartridge filtering a fluid comprising:

• securing means for connecting a twist-on cartridge to the head, the securing means having a pair of diametrically opposite tab receptacles, each tab receptacle having a cam surface, and each tab receptacle being fixedly attached to the head;
• and
• locking means for preventing untwisting of the cartridge from the head, wherein the locking means comprises:
• a plunger being disposed in a hole in the head and adapted to be received in a detent disposed in the cartridge in a locked position, the plunger also being disposed in a peripheral direction about an axis of symmetry of the head and midway between the tab receptacles on the head, the plunger having a helical spring urging the plunger toward the locked position for engagement with the detent, and the plunger also having an extension disposed in a slot in the head, said extension having a finger tab for lifting the plunger to an unlocked position.

A filter cartridge and head unit comprising:

• a head having an inlet passage and an outlet passage;
• a cartridge having a cavity for filter material;
• securing means for twisting the cartridge onto the head;
• and
• locking means for preventing untwisting of the cartridge;
• said locking means comprising:
• a plunger being displaceable on the head and having a locked position and an unlocked position;
• and
• a detent for receiving the plunger in the locked position and providing a predetermined angular orientation and an automatic locking action to indicate completion of the twisting of the cartridge onto the head, and further for withstanding a substantial shear force from the plunger in the locked position occurring when the cartridge is subject to an untwisting torque, so that the filter cartridge can only be removed from the head by first lifting the plunger into the unlocked position.

A filter unit for filtering a fluid comprising:

• a head for mounting on a support;
• a twist-on cartridge for containing a filtering material for filtering the fluid;
• securing means for connecting the cartridge to the head;
• and
• locking means for preventing untwisting of the cartridge from the head, wherein the lock means comprises:
• a plunger disposed in a hole in the head, the plunger having a helical spring urging the plunger toward a locked position for engagement;
• and
• at least one detent disposed in the cartridge for receiving the plunger in the locked position.

A head unit for a filter cartridge filtering a fluid comprising:

• an inlet passage and an outlet passage;
• securing means for connecting a twist-on cartridge to the head;
• and
• lock means for preventing untwisting of the cartridge from the head, wherein the lock means comprises:
• a plunger being supported by the head and disposed in a hole in the head, said plunger being displaceable from an unlocked position to a locked position and adapted to be received in a detent disposed in the cartridge when in the locked position so that the filter can only be removed from the head only by first lifting the plunger into the unlocked position.

A head unit for a filter cartridge filtering a fluid comprising:

• securing means for connecting a twist-on cartridge to the head;
• and
• locking means for preventing untwisting of the cartridge from the head, wherein the locking means comprises:
• a plunger disposed in a hole in the head adapted to be received in a detent disposed in the cartridge in a locked position, the plunger having a helical spring urging the plunger toward a locked position for engagement with the detent, and the plunger has an extension disposed in a slot in the head, said extension having a finger tab for lifting the plunger to an unlocked position.