Vacuum device with positive pressure tank

In a device that uses the tank from a conventional vacuum cleaner, the tank is under positive pressure. A cap fits over a tubular element inside the tank and closes the conventional air inlet. The cap has a peripheral wall that extends between a solid back and a front radial rim, and interior axial ribs. The lid is held by a latch that has an element that pivots with respect to the tank and the lid, and a clasp that has a bent arm. A tensioner pulls the bent arm. The tensioner has a threaded rod that extends from a handgrip though a hole in the pivoting element. A nut on the clasp receives a threaded end of the threaded rod, enabling the handgrip to be used to tighten the clasp. An outer wall of the latch is disposed outwardly of the threaded rod and the bent arm.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

BACKGROUND OF THE INVENTION

The present invention relates generally to vacuum devices and particularly to conventional vacuum cleaners that are modified for use in circumstances where the tank is under positive pressure, rather than negative pressure.

BRIEF SUMMARY

A new mulching vacuum device has been developed that uses the tank from a conventional vacuum cleaner. In the new device, a new inlet has been provided in the lid and the airflow has been redirected so that the tank is under positive pressure, rather than negative pressure. New elements were developed to implement this new arrangement.

The new vacuum device uses the tank from a conventional vacuum cleaner. The tank has an open rim on which a newly designed lid fits. The new lid has both an inlet and an outlet through which exhaust air exits the vacuum device. A vacuum source on the lid draws air into the vacuum device through the inlet. The air blows into the tank before being exhausted, leading to the interior of the tank being under positive pressure.

The conventional tank that is used in this vacuum device has an opening that is designed for use as an air inlet. This opening is provided with a tubular element. In a conventional vacuum cleaner, this tubular element serves to deflect incoming airflow downwardly toward the bottom of the tank. In the new vacuum device, collected debris could blow out of this opening.

A new positive pressure cap was developed to prevent this. The removable cap fits over the tubular element inside the tank and closes the opening when the tank is pressurized by the vacuum source. The cap has a peripheral wall that extends between a solid back and a front radial rim, and interior axial ribs.

Because the tank in the new vacuum device is under positive pressure, rather than negative pressure, a new latching mechanism was developed to ensure that the lid stays secured to the open rim. The new latch has a pivoting element that pivots with respect to the tank and the lid, and a clasp that has a bent arm that fits against a latch rim. A tensioner that is connected to the pivoting element pulls the bent arm against the terminal edge of the latch rim and thus holds the lid against the open rim. The tensioner has a handgrip and a threaded rod that extends from the handgrip though a hole in the pivoting element. A nut that is fixed on the clasp receives a threaded end of the threaded rod, enabling the handgrip to be used to tighten the clasp. An outer wall of the latch is disposed laterally outwardly of the threaded rod and the bent arm on the clasp.

DETAILED DESCRIPTION

FIG. 1illustrates one embodiment of a vacuum device10that has been modified for use in an arrangement in which the tank is under positive pressure, rather than negative pressure. The illustrated vacuum device is adapted with a mulcher that can be used for mulching yard waste such as leaves and branches. However, the modifications may also be useful in other settings.

The illustrated vacuum device has a tank12, a lid14, a removable cap16, and a latch18. Each part will be discussed below.

The Tank

The tank12is used to store waste, and can vary in volume. The tank that is seen inFIG. 1is a conventional tank used in wet/dry vacuum cleaners. It holds liquid (it is made of solid plastic) and has an interior reservoir that has a volume of between 1 and 55 gallons. The tank has a rigid open rim20on the top and a defined opening22on the side.

The open rim provides a location where the lid can be attached. The illustrated open rim is generally circular in shape and is between 8″ and 36″ across, but the size and shape can vary. Preferably, the open rim is large enough to accommodate a conventional wet/dry vacuum filter, and enable the contents of the tank to be easily dumped by the operator.

The illustrated opening22on the tank12leads to the interior of the tank, and is one that is configured to receive a hose so that the opening can be used as an inlet for conventional vacuuming. The illustrated opening is between 1″ and 4″ in diameter and has a conventional threaded external segment where a hose can be attached. As seen inFIG. 2, the opening also has a tubular element24that extends inwardly into the tank and is between 1″ and 4″ long. The illustrated tubular element bends downwardly into the tank. In other devices, the tubular element bends tangentially (sideways) into the tank, or downwardly and tangentially (partially downwardly and tangentially, i.e., angled).

When the tank is used with a conventional vacuum cleaner, debris-laden air can be drawn into the tank through the opening, and this tubular element deflects the air downwardly toward the bottom of the tank.

The illustrated tank12also has optional casters26on the bottom. These conventional casters help a user to move the vacuum device from one location to another.

The Lid

The lid14fits onto the open rim of the tank12, and houses a vacuum source. Although other materials could be used, the illustrated lid is made of plastic. When installed on the tank, it seals the open rim20of the tank, effectively stopping air from blowing out of the open rim of the tank. For use as a mulcher, the illustrated lid has both an inlet40and an outlet42, each described below.

A wide variety of different types of vacuum sources can be used. The vacuum source used in this lid12is an electric motor/fan assembly that provides suction and, for use in a mulcher, helps to draw yard waste into the device. In particular, the motor/fan assembly seen in co-pending application Ser. No. 11/859,760 (published as US-2008-0072396-A1) may be used. (The disclosure of that application is incorporated into this application be reference.) That vacuum source is particularly useful because it can be removed from the lid for servicing.

The inlet40provides entry to a flow path through the vacuum device10. The illustrated inlet is in the form of 1″ to 8″ diameter rigid plastic conduit that is positioned over the top of the lid and leads to the vacuum source. Other arrangements are possible. When the vacuum source operates, it draws air and yard waste into the vacuum device through the inlet. Downstream of the vacuum source, the force of the vacuum source creates positive pressure in the tank12.

The pressurized air downstream of the vacuum source is exhausted through the outlet42on the lid14. The illustrated outlet is a 1″ to 5″ wide by ½″ to 4″ tall opening within a rigid rim44on a side of the lid. Other arrangements are possible.

The Removable Cap

The removable cap16fits closes the opening22on the tank12is pressurized by the vacuum source. As seen inFIG. 1, the cap is shaped to fit over the tubular element24on the inside of the opening22on the tank. The illustrated cap has a peripheral wall62see inFIGS. 3-5that extends between a solid back64and a front radial rim66. In width and length, the peripheral wall is sized larger than the tubular element, enabling the cap to fit over the tubular element. The front radial rim extends another 1/16″ and ⅜″ inwardly from the inside surface of the peripheral wall.

The illustrated cap16also has interior axial ribs68that extend between the back64of the cap and the front radial rim66. The four ribs that are shown inFIGS. 5 and 6are spaced evenly across the circumference of the cap. These ribs fit snugly against the tubular element24, and each project inwardly between 1/16″ and ¼″ from the inside edge of the front radial rim66. The progressively wider inside dimensions of the ribs, the front radial rim, and the peripheral wall62make it easier to install the cap over the tubular element, while still effectively preventing debris from blowing out through the opening22. For other tubular elements, the configuration of the cap may be different.

The peripheral wall62, the back64, the front radial rim66, and the ribs68of the illustrated cap are all made of the same material, in this case a plastic material. This facilitates manufacture.

The Positive-Pressure Latches

FIGS. 1 and 2show a positive pressure latch18on one side of the vacuum device10. A matching latch is used on the other side of the device. These latches hold the lid14to the open rim20on the tank12. As better seen inFIGS. 7 and 8and discussed in more detail below, each latch has a pivoting element70, a clasp72, a tensioner74, and an outer wall76. The pivoting element is connected to either the lid or the tank. If it is connected to (i.e., permanently joined to) the lid, as it is here by connectors77(FIG. 1), then a matching latch rim78is connected to the tank, as seen inFIGS. 1 and 2. If the pivoting element is connected to the tank, then the latch rim is connected to the lid.

The pivoting element70pivots with respect to the tank12and the lid14. The pivoting element seen inFIGS. 7 and 8has an inner face80that extends downwardly from a top face82. A central axis84extends generally parallel to the inner face, and a horizontal pivot86at a lower end of the inner face connects to the lid. The horizontal pivot is aligned with an axis87that is stationary with respect to the lid and enables the central axis of the pivoting element to be tilted about the horizontal pivot and thus rotated with respect to the lid about the stationary axis, moving an outer end88of the pivoting element towards and away from the tank. The required range of motion of this pivoting movement will be discussed below.

The latch rim78(FIGS. 1, 2, and 9) has a terminal edge90and a lateral side92against which other elements of the latch are secured. As mentioned above, the illustrated latch rim is connected to the tank12, and the lateral side of the latch rim is spaced between ¼ of an inch and 1 inch away from the rest of the tank. The lateral side ends at the terminal edge, which is arranged horizontally and is between ½″ and 3″ in length. The lateral side is made of a rigid material and is strong enough to hold the lid to the tank.

The clasp72is movably connected to pivoting element70and, as explained below, arranged so that it can be moved along the central axis84of the pivoting element. For locking the lid14to the tank12, a bent arm94on the clasp fits across the terminal edge90of the latch rim78and against the lateral side92of the latch rim. The illustrated bent arm is between ½″ and 2″ wide, and has a hook portion96that is between 1/16″ and ½″ high. When the latch is closed, as seen inFIG. 9, interference between the hook portion and the lateral side of the latch rim helps to prevent the clasp from breaking engagement with the latch rim.

The tensioner74is connected to the pivoting element70and pulls the bent arm94of the clasp72against the terminal edge90of the latch rim78and thus holds the lid14against the open rim20of the tank12. The tensioner has a threaded rod100that extends though a hole102in the top face82of pivoting element70. The illustrated threaded rod is a steel rod with a diameter of between ⅛″ and ⅜″. A threaded end104of the threaded rod receives a nut106that is fixed in the clasp. The illustrated nut is a standard hex nut fixed in a chamber in a lower section of the clasp. A handgrip110on the opposite end of the threaded rod enables a user to easily rotate the threaded rod. The illustrated handgrip is a plastic knob that is between ½″ and 2½″ wide. Rotating the rod in one direction advances the threaded rod in the nut. When the bottom of the knob lies against the top face of the pivoting element, this movement draws the clasp closer to the top face of the pivoting element. Rotating the rod in the other direction retracts the rod, allowing the clasp and the pivoting element to move apart.

To detach the lid14from the tank12, the threaded rod100is first loosened so that the hook portion96of the clasp72can clear the terminal edge90of the latch rim78. The pivoting element70is then pivoted outwardly, enabling the hook portion of the clasp to be moved outwardly beyond the latch rim, and thus enabling the lid to be lifted off the tank.

To secure the lid14to the tank12, the process is reversed. As the lid is moved toward the rim, a sloped upper side112on the latch rim78may be used to deflect the hook portion96of the clasp72outwardly until it clears the latch rim. The center of gravity of the disclosed pivoting element70, clasp, and tensioner74is laterally outwardly of the horizontal pivot86. As a result, gravity urges the clasp to rotate inwardly toward the tank, moving the those elements into a position where advancing the threaded rod100draws the hook portion of the bent arm94of the clasp into the gap between the lateral face92of the latch rim and the rest of the tank.

This description of various embodiments of the invention has been provided for illustrative purposes. Revisions or modifications may be apparent to those of ordinary skill in the art without departing from the invention. The full scope of the invention is set forth in the following claims.