Machine element or mechanism – Control lever and linkage systems – Elements
Reexamination Certificate
1999-03-03
2001-01-30
Green, Mary Ann (Department: 3682)
Machine element or mechanism
Control lever and linkage systems
Elements
C074S548000
Reexamination Certificate
active
06178848
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to vehicle jacks and, more particularly, to an improved handle for actuating such jacks.
Motor vehicles have traditionally been equipped with a spare wheel to use in the event that one of the tires became flat or disinflated. Along with a spare wheel, some means for raising the vehicle in order to change the wheel must be provided. This means of lifting the vehicle has usually been some form of vehicle jack.
Some vehicle jacks have heretofore been designed to be positioned underneath the vehicle, usually just to the inside of the tire to be changed and the designated lifting point is generally the axle or other nearby wheel support structure. These jacks may be either of a scissors-type or a telescoping-type and normally utilize a screw drive. In both cases, a rotary force is applied to an operator or coupling on the end of a screw drive to either raise or lower the vehicle depending upon whether the rotary motion is clockwise or counterclockwise.
To impart that rotary motion to the jack, a handle is attached to the jack spindle both, to transmit the rotary motion to the jack and, to help position the jack at the proper lifting location underneath the vehicle. The jack handle must be long enough to reach from the perimeter of the vehicle to the jack which is positioned underneath the vehicle while still allowing enough room for the operator to apply the rotary motion to the end of the handle remote from the jack.
Some of the current jack handles on the market have a solid metal end with a generally L-shaped tip or hook on one end of the jack handle. This hook is engaged with an operator on the base of the jack which allows the jack handle to be used to push and pull the jack to position it underneath the vehicle. Furthermore, the hook drivingly engages the jack operating coupling and transmits the necessary rotary motion and torque from the jack handle to the jack screw in order to lift the vehicle.
Referring to
FIG. 1
, to manufacture the hook and jack handle assembly, a hook
14
is formed in a first end
13
of a solid metal end piece
12
which has an opposite end
18
with a noncircular cross-section. The opposite end
18
of the end piece
12
is inserted into a tubular section
20
of the jack handle
22
and then held in place while a stake or crimp (not shown) is applied to the outer surface of the tubular section
20
. In theory, the crimp should simultaneously form mating depressions in both the tubing wall
16
and opposite end
18
of the end piece
12
, which should secure the end piece
12
to the end of the jack handle
22
and prevent the end piece
12
from separating from the jack handle
22
during normal use.
In practice, however, often, this is not what happens. As the crimp punch displaces the material in the tubing wall
16
, the tubing wall material is merely compressed and thinned out to form a notch
26
between the crimp punch and the end piece
12
, as shown in FIG.
1
. The tubing wall does not displace the adjoining material in the end piece
12
as one would expect. If the crimping force is increased with the intent of causing the punch to penetrate into the end piece material, the tubing wall
16
is often punched through as shown at notch
28
in FIG.
2
. Alternatively, only an extremely thin section of tube wall
16
is left in the depression formed in the end piece
12
, which will not adequately retain the end piece
12
in the jack handle
22
when forces such as an axial load are applied to the hook and jack handle assembly.
In order to meet the torque requirements placed on the hook and jack handle assembly, the tensile strength of the end piece
12
is greater than the tensile strength of the tubular section
20
of the jack handle
22
. This would account for the softer tubing wall
16
not being able to displace the harder end piece material. Also the thin tubing wall
16
presents a much less substantial structure than the solid end piece
12
. Thus, the tubing wall
16
is simply displaced by the punch instead of being able to work the material of the end piece
12
.
As a result of the tubing wall
16
not displacing the material in the end piece
12
, the minimal contact between the end piece
12
and tubing wall
16
at the crimp area creates a frictional force that temporarily holds the end piece
12
in place within the jack handle
22
. Once the jack handle is used, however, the forces applied to the hook
14
and jack handle
22
can cause the tubular section
20
to relax slightly, that is, to deflect or move, and the contact between the tubular section
20
and end piece
12
is lost. The end piece
12
with hook
14
can then be easily dislodged from the jack handle
22
when longitudinal forces apply an axial load, such as when the hook and jack handle assembly is used to pull the jack (not shown) from underneath the vehicle.
There is thus a need to provide a hook and jack handle assembly in which the hook will not unexpectedly separate from the jack handle during normal use of the vehicle jack.
SUMMARY OF THE INVENTION
The present invention provides a hook and jack handle assembly for use in operating vehicle jacks in which the hook is permanently retained within the tubular end portion of the jack handle such that the jack handle assembly operates more reliably over the useful life of the jack. To this end and in accordance with the principles of the present invention, there is provided an end piece with a hook at one end and a pre-formed notch or depression in the other end for inserting into the end of a tubular jack handle to form a hook and jack handle assembly for operating a vehicle jack. Upon crimping the tubular wall of the jack handle, the punch engages the tube wall and forms a crimp or indentation within and/or forced into contact with the pre-formed notch in the end piece. This results in a substantial thickness of the tubing wall being depressed into the notch in the end piece such as to prevent the end piece from being removed and not subject to being separated from the jack handle during its normal use. Thus, the jack handle assembly of the present invention has the advantages of being easier to use and more reliable over the life of the assembly.
REFERENCES:
patent: 1108212 (1914-08-01), Nelson
patent: 5878627 (1999-03-01), McMurtrey
Green Mary Ann
Wald LLC
Wood Herron & Evans LLP
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