Handling: hand and hoist-line implements – Utilizing fluid pressure – Venturi effect
Reexamination Certificate
1997-12-19
2002-02-12
Kramer, Dean J. (Department: 3652)
Handling: hand and hoist-line implements
Utilizing fluid pressure
Venturi effect
C414S627000
Reexamination Certificate
active
06345850
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to an apparatus for lifting objects and, more particularly, a vacuum lifter.
2. Description of the Related Art
FIG. 1
illustrates a prior art vacuum lifter
10
for lifting and transporting an object
12
. The object
12
may take any form as long as at least one surface
14
is smooth and firmly fixed to the object
12
. The vacuum lifter
10
includes an overhead vacuum hose
16
that is airtight. The overhead hose
16
has a substantially vertical portion terminating in a first end hermetically connected to the intake of a vacuum pump (not shown). A second end of the overhead hose
16
hermetically connects to a metal housing
18
. The hose
16
is supported by an overhead structure (not shown) that supports the weight of both the lifter
10
and, when lifted, the object
12
. In some cases, the overhead structure includes rollers and tracks (not shown) that facilitate horizontal displacements of the loaded lifter
10
.
The housing
18
has airtight internal passages (not shown) that connect the overhead hose
16
to one or more secondary hoses
20
. The housing
18
also has a support structure
22
fixedly connecting one or more sealing plates
24
to the bottom thereof. Each secondary hose
20
hermetically connects to an upper surface of the sealing plate
24
and connects with a lower surface thereof through one or more holes
26
that pierce the sealing plate. A pliable sealing ring
30
attaches to the entire perimeter of the lower surface of each sealing plate
24
. The sealing ring
30
hermetically seals the lower surface of the sealing plate
24
to the top surface
14
of the object
12
upon compression therebetween.
One or more handles
28
project from the housing
18
. A control lever
32
projecting from the housing
18
operates internal valves (not shown) which regulate the vacuum pressure in the secondary hoses
20
. The vacuum lifter
10
forms a sealed conduit between the intake of the vacuum pump (not shown) and the surface
14
of the object
12
when a vacuum is created therein.
FIG. 2A
illustrates the operation of the vacuum lifter
10
. The vacuum lifter
10
is positioned so that the sealing plate
24
is snug against the smooth surface
14
of the object
12
. A vacuum is produced between the surface
14
and the sealing plates
24
by means of the secondary hoses
20
. The vacuum forms a suction that grips the object
12
to the lifter
10
. Since the conduit formed by the overhead hose
16
between the sealing plates
24
and the vacuum pump (not shown) is hermetically sealed, the vertical portion of the overhead hose
16
is flexible and shortens as the vacuum therein is increased.
As the vertical portion of the overhead hose
16
shortens, the object
12
is lifted off the ground
34
. An operator
36
may adjust the height of the object with the control lever
32
that regulates the vacuum in the overhead hose
16
and the length thereof by allowing air to enter through valves (not shown) connected to the outside. After the object
12
is positioned at the desired height, the operator
36
moves the vacuum lifter
10
and the attached object
12
by pushing or pulling with the handles
28
or by pushing or pulling on the object
12
itself.
FIG. 2B
illustrates the removal of the vacuum lifter
10
from the object
12
after the object
12
is positioned on the desired surface
38
. The operator
36
allows air to enter the secondary hoses
20
to release the vacuum between the sealing plates
24
and the surface
14
. The object
12
is consequently released from the vacuum lifter
10
. After the vacuum is released, the operator
14
attempts to slide the vacuum lifter
10
off without disturbing the positioning of the object
12
.
Since the vacuum lifter
10
is heavy, the operator
36
may have difficulty in sliding the lifter
10
both on and off the object
12
to be lifted. Sliding the vacuum lifter
10
on or off is specially difficult when the object
12
has been placed on a surface above the shoulders of the operator
36
. Since the vacuum lifter
10
cannot be easily slid on or off objects
12
positioned at shoulder height, the lifter
10
is less useful as a warehouse tool.
Some vacuum lifters
10
allow reversing the air flow in the secondary hoses
20
. After the air flow is reversed, the lifter
10
rests on a cushion of air between the sealing plates
24
and the surface
14
of the object
12
. The cushion of air facilitates sliding the vacuum lifter
10
on or off the object
12
. Unfortunately, reversing the air flow in the vacuum lifter
10
requires relatively substantial time because the overhead hose
16
is wide and must generally be refilled with air. For such prior art lifters
10
, the operator
36
may have to wait thirty seconds for the vacuum pump to form a sufficient air cushion. In some other lifters
10
, a reversal of the airflow is inconvenient because reversing the airflow eliminates the lifting force exerted by the overhead hose
16
. These construction and time delay constraints compromise the usefulness of reversal of the internal airflow as an aid to sliding the lifter
10
on or off an object.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
SUMMARY OF THE INVENTION
The present invention, in one embodiment, is a vacuum lifter. The vacuum lifter includes an overhead hose, a housing, and a roller rotatably fixed to the housing. The housing is adapted to roll on the roller.
REFERENCES:
patent: 3858926 (1975-01-01), Ottenhues
patent: 4822236 (1989-04-01), Inoue et al.
patent: 4846625 (1989-07-01), Gabillet
patent: 5330314 (1994-07-01), Bennison
patent: 5478066 (1995-12-01), Yoshida et al.
patent: 5645274 (1997-07-01), Ubayashi et al.
patent: 4229208 (1994-03-01), None
patent: 1049405 (1983-10-01), None
patent: 1058865 (1983-12-01), None
patent: 1364592 (1988-01-01), None
Product BulletinVT Series Vacuum Lift System(Anver Corporation) Date Unknown, 3 pages.
Chin Paul T.
Kramer Dean J.
Micron Electronics Inc.
Trop, Pruner, Hu & Miles, P.C.
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