[0001] The present invention relates to a vehicle lifting jack for raising and lowering
a vehicle for changing a wheel of which the tire has become unusable.
[0002] Lifting jacks are known which are Y-shaped comprising a column with a foot for resting
on the ground. To the column a lifting arm with a U-shaped stirrup or end support
is hinged to support the lifted vehicle. For this purpose the vehicle is provided
with corresponding flanges on the underside of the bodywork, which may partly come
to rest in a channel of the stirrup. The column and the lifting arm of this type of
lifting jack are associated with one another by way of a spindle screwed in a nut
pivotably connected to the top of the column, while one end of the spindle is rotatably
and pivotably connected to the end of the arm and the other end of the spindle has
attached thereto a cranked handle, normally pivotably attached thereto, to operate
the jack for lifting or lowering the vehicle. For this purpose the end of the spindle
which is rotatably and pivotably connected to the end of the lifting arm is provided
with a bearring. Obviously the relative position of the bearing and the nut which
is disposed at the top end of the jack column could be reversed.
[0003] The base of the column of the known types of lifting jacks, which rests on the ground,
moves or rocks relative thereto with the relative tilt of the column varying, since
said base is fixedly attached to the column. The stability of the lifting jack is
negatively effected, since the initial positioning of the jack to achieve a stable
lifting motion and finally the positioning of the vehicle are critical.
[0004] There are also known leaf spring or articulated lifting jacks which are formed by
arms hingedly connected together in a parallelogram form. The spindle is located on
the substantially horizontal diagonal of this parallelogram with one end of the spindle
being screwed to a nut which is attached to one of the apexes of the parallelogram
and with the other end thereof rotatably attached to the opposite apex of the parallelogram.
The spindle projects outwardly beyond one of said apexes for connection with the cranked
handle. This type of lifting jack has one base member pivotably attached to the lower
apex of the parallelogram to support the jack on the ground and another base member
at the upper apex to support the underside of the vehicle bodywork.
[0005] In the initial lifting stage the cranked handle of this known lifting jack is located
very close to the ground which makes handling difficult, both during the initial lifting
and the final lowering phase of the vehicle, and may even cause injury of the hand
of an user because of possible ground contact.
[0006] Likewise, with both known types of lifting jacks, the corresponding underside of
the vehicle bodywork to be lifted is provided with one or more flanges which will
be inserted in a groove or a channel of the liftable stirrup, support or base member
of the jack, which is V-shaped in cross section. Nevertheless, this shape of the channel-shaped
stirrup of the lifting jack does not - depending on the height to which the vehicle
is lifted by the user and depending on the initial positioning of the jack relative
to the vehicle body as selected by the user - prevent the lower flange of the vehicle
body from coming to rest against the narrowest or closest part of the stirrup groove
or channel. Therefore the flange of the vehicle may be deformed because of the relative
rotation between this part of the vehicle and the stirrup by which it is supported,
with a consequent damage to the flange itself and subsequent difficulties in lifting
the vehicle on a future occasion with the same jack. Or worse, the flange may become
useless or may even break.
[0007] A vehicle lifting jack according to the invention is a new type of a lifting jack
with four mutually pivotably attached arms disposed in a parallelogram form, with
a spindle located on a diagonal of said parallelogram, which is preferably horizontal
or approximately horizontal when the jack is in the lifted position, with one end
passing through a nut pivotably attached to an apex of the parallelogram and with
the other end passing through a cross member which is pivotably attached to the opposite
apex of the parallelogram, one end of the spindle being terminated by a stop member
which rotatably bears against the cross member, preferably through a bearing; said
spindle is provided, at one of the two ends thereof, with a handle, preferably a cranked
handle, or with temporary connection means for such a handle for being caused to rotate
by the user; the lower rear arm of the parallelogram, which extends from the rear
apex thereof, is extended below said lower apex, forming a support leg for the jack,
which is pivotably connected to a floor support foot; and a stirrup for supporting
and retaining the vehicle is provided on a short front extension of the upper rear
arm of the parallelogram to which it is relatively rotatably connected, said stirrup
having a cross section similiar to a Greek letter omega which is inverted with respect
to said front extension, is able to rotate relative to the end of the arm on which
it is mounted on a preferably ideal axis transverse or nearly transverse to the center
line of said arm which is provided with linking means associating it with respective
means provided on the stirrup, allowing the latter to rotate relative to said center
line, but preventing it from moving in a transverse direction.
[0008] According to the invention the linking means between the stirrup and the end of the
upper rear arm of the parallelogram peferably consists of respective parallel peripheral
channels which are open to opposite directions. These channels are situated on the
outer circular surface of the stirrup and form respective circular arcs. With these
channels there are engaged respective inwardly folded flanges of the end of the upper
rear arm of the parallelogram, which are disposed facing each other and forming respective
circular arcs mating with the arcs of said peripheral channels.
[0009] By the vehicle lifting jack of the invention the problems mentioned in connection
with the known types of lifting jacks are obviated and, among others, the following
advantages are provided: greater stability; lower manufacturing cost for the same
height; smaller volume occupied, making storage in any part of the vehicle easier;
greater lifting height, for the same dimensions in the folded position of the jack;
unfolding the jack to its maximum lifting height with less turns of the cranked handle,
increasing user convenience; faster lifting and lowering of the vehicle to be lifted
or lowered, saving time to the user; achieving a desirable separation or spacing apart
of the lower flange of the vehicle bodywork from the groove or channel wall(s) of
the stirrup of the jack throughout the whole vehicle lifting or lowering operation;
automatic adaptation of the stirrup to the relative movement or rotation of the vehicles
underfloor with respect to the ground, without the possibility of transferring harmful
torques; and the possibility of making the stirrup as long as desired with respect
to the axis of rotation, without limitations in view of the specific constitution
of the relative linking means between the stirrup and the end of the upper rear arm
of the parallelogram.
[0010] The vehicle lifting jack of the invention affords the advantages described above,
apart from others which will be readily appreciated from an example of a preferred
embodiment described in further detail hereinafter to facilitate the understanding
of the features described, disclosing at the same time sundry details. Attached hereto
are certain drawings of a preferred embodiment of such a lifting jack which is by
no means a restricting example to the scope of the present invention.
[0011] Below a vehicle lifting jack according to the invention will be described by reference
to the figures. Further advantages and features of the present invention will be disclosed.
In the figures:
Figure 1 is a side elevational view of a lifting jack in its folded position with
a cranked handle folded away; a jack spindle is shown schematically in phantom line;
Figure 2 is a side elevational view of the jack partly unfolded and engaging with
the underside of a vehicle body of which the lower portion of a flange of the vehicle
is illustrated in phantom line;
Figure 3 is a side elevational view of the jack in a raised position, corresponding
in this case to the position of maximum height, with the vehicle lifted to a raised
position, showing a portion of the spindle and a maximum lift stop member; and
Figure 4 is the sectional view A-A' of Figure 2 showing a detail of a pivoted connection
of a stirrup to an end of a lifting arm of the jack.
[0012] According to the Figures, a vehicle lifting jack is provided with four arms 1, 2,
3 and 4, pivotably connected and forming a parallelogram. The lifting jack is provided
with a spindle 5, schematically shown by a center line in Fig. 1 and 2, which is extended
along a diagonal of said parallelogram. The angular position of this diagonal changes
when the jack is operated as can easily be seen by comparing Figures 1, 2 and 3.
[0013] In this embodiment there is a cranked handle 6 connected inseparably and pivotably
at a rear end of the spindle 5 and serving as a means by which the spindle 5 is rotated
during a lifting or lowering action causing the jack to unfold or fold down, i.e.
to lift or lower a stirrup 10 of the jack and the vehicle bodywork engaged therewith.
Obviously the spindle 5 may be rotated by other means which may have a separable attachment
located between the handle 6 which is suitably shaped and the rear end of the spindle
5 to facilitate easy storage in the vehicle when the jack is not used.
[0014] The lower rear arm 2 of said parallelogram has a lower extension 2a serving as support
leg for the jack, spacing the parallelogram apart from the floor. Said extension 2a
is pivotably connected to a foot 7. To restrict pivoting between the lower extension
2a and the foot 7, stop means may be provided consisting of additional members or
members defined by the very shape of the lower edge of the lower extension 2a, as
shown in Fig. 1, 2 and 3. Spring means may also be provided to retain the foot 7 in
the position shown in Figure 1 when it is folded down. In this embodiment the spring
means is a wire spring attached at one end to the lower extension 2a and supported
at the other end on the foot 7, having one or more turns wounded around the pivot
shaft between the lower extension 2a and the foot 7.
[0015] The four arms 1 to 4 of the lifting jack may be formed by U-shaped sections connected
by respective pivot pins or, in another embodiment, they may be formed by pairs of
parallel flat bars spaced apart by respective cores acting as pivot shafts of the
arms to form a parallelogram. Suited Combinations of such sections may be used in
one jack and furthermore the specific configuration of said arms could be any other,
depending on manufacturing needs and under consideration of the stress to which they
might be exposed.
[0016] The foot 7 is provided with two parallel wings, such as the wing 8, to the outside
of which there are, in this embodiment, pivotably connected two side members which
constitute the lower rear arm 2 with its lower extension 2a. It should be appreciated
that each of these two side members is formed by a C-shaped section, although it may
obviously be formed, as already mentioned, by any other type or form of sections and
even by a single appropriate section.
[0017] The front end of the spindle 5 is supported by support or stop means which may consist
of a bearing 9 or any other suitable means which, likewise, holds said spindle end
in position and facilitates the rotation thereof relative to the front apex of the
parallelogram. Said spindle 5 is screwed in threaded or nut means pivotably attached
to the rear apex of the parallelogram, i.e., at the upper portion of the lower rear
arm 2. This means allows the spindle 5 to move relative to said rear apex of the parallelogram
depending on the direction of rotation of the handle 6. The relative position of the
bearing 9 or the like and the nut could be reversed, i.e. the latter could be disposed
at the front apex of the parallelogram and the bearing 9 at the rear apex thereof.
[0018] An upper rear arm 1 of the parallelogram has a short upper extension on which there
is disposed the stirrup 10, which is rotatably attached to this arm 1. The stirrup
10 exhibits a cross section similiar to the Greek capital letter omega laying upside
down or nearly upside down with respect to the underside of a vehicle bodywork which
has to be lifted or lowered. Therefore the stirrup 10 is assembled such that it is
able to rotate relative to the end of the upper extension of the upper rear arm 1.
The axis of rotation extends in parallel to an ideal or nearly ideal transverse axis
perpendicular or almost perpendicular to the longitudinal axis of the upper rear arm
1.
[0019] The end of the upper rear arm 1 is provided with linking means by which it is associated
or attached to respective means of the stirrup 10, to allow the latter to rotate around
said transverse axis, but to prevent it from moving in a transverse direction. Said
linking means between the stirrup 10 and the end of the upper rear arm 1 consist of
respective mutually parallel and opppositely facing peripheral channels, such as the
channel 11, which are located on the outer circular surface of the stirrup 10, forming
respective circular arcs. As shown in Fig. 4 said channels 11 may be defined by a
formed flat bar 12 firmly attached, for example by welding, to the circumference of
the stirrup 10, most preferably at its central portion. The bar 12 is provided with
respective deviations at the parallel end edges thereof which form the channels 11.
The bar 12 could be replaced by two narrower, also formed bars 12 and, likewise, said
channels 11 could be formed in the stirrup 10 itself by cutting and/or swaging.
[0020] Respective inwardly bent flanges 13 provided at the end of the upper rear arm 1 of
the parallelogram are engaged with the channels 11 by insertion. Said flanges 13 are
disposed facing each other and also forming circular arcs mating with the arcs of
the channels 11 of the formed flat bar 12.
[0021] In the stirrup 10 there will be freely housed a lower flange 14 provided at the corresponding
underside of the vehicle bodywork (shown in part in phantom lines in Figures 2 and
3) which is reinforced in this region to withstand the mechanical stress derived from
the force of the stirrup 10 to lift the vehicle. Between the initial lifting position
of the vehicle and its final or maximum height position above the ground, the stirrup
10 rotates relative to the end of the upper rear arm 1 in a counterclockwise direction
as can be seen at Fig. 2 and 3. The flange 14 of the vehicle is loosely housed in
the stirrup 10. Damage to the flange 14 of the vehicle is prevented and save support
of the flange 14 in the stirrup 10 is maintained. Because of the design and the attachment
of the stirrup 10 balance of the lifting jack is maintained throughout the complete
lifting or lowering operation and, of course, in the final vehicle lifting position
during exchange of a faulty wheel.
[0022] The spindle 5 may be provided with a stop means such as a bushing 15 to limit the
maximum height position of the lifting jack and, at the same time, facilitating easy
handling by eliminating possible dead points or points close thereto in the parallelogram
mechanism.
[0023] Finally, the foot 7 may also be provided with resilient blocks to improve its adherence
to the floor or with lower projections in order to enhance its gripping characteristics.
[0024] It is easy to gather how the jack may be used, even for an unskilled person. In view
of the drawings and the description other or additional features and advantages of
the invention will become apparent.
[0025] It should be pointed out that in the embodiment of the vehicle lifting jack of the
invention, all variations of detail that experience and practice may recommend with
regard to forms and dimensions, both absolute and relative, number of component pieces
and parts, materials used therein and other accessory details may be applied and also
that as many modifications of constructive detail as being compatible with the essence
of the claimed matter may be introduced, all is still comprised within the object
of the claims.
1. A vehicle lifting jack is provided with four mutually pivotably attached arms (1 to
4) disposed in a parallelogram form, with a spindle (5) extending along a diagonal
of the parallelogram with one end passing through a nut pivotably attached to an apex
of the parallelogram and with the other end passing through a cross member which is
pivotably attached to the opposite apex of the parallelogram, one end of the spindle
(5) being terminated by a stop member which rotatably bears against said cross member,
preferably through a bearing (9);
said spindle (5) is provided, at one of the two ends thereof, with a handle (6),
preferably a cranked handle (6), or temporary connection means for a handle (6) for
being caused to rotate by the user;
the lower rear arm (2) of the parallelogram extends from the rear apex thereof
and is extended below said lower apex, forming a support leg (2a) for the jack, which
is pivotably connected to a floor support foot (7); and
a stirrup (10) for supporting and retaining the vehicle is provided on a short
front extension of the upper rear arm (1) of the parallelogram to which it is rotatably
connected, to which end said stirrup (10) has a crossectional shape similiar to an
inverted Greek letter omega with the ability to rotate relative to the end of the
upper rear arm (1) on which it is mounted on an axis transverse or nearly transverse
to the center line of said arm (1) which is provided with linking means (13) associating
it with respective means (12) provided at the stirrup (10) allowing the latter to
rotate relative to said center line, but preventing it from moving in a transverse
direction.
2. Vehicle lifting jack according to claim 1, wherein the linking means (12) of the stirrup
(10) preferably consist of respective parallel peripheral channels (11), open in opposite
directions, situated on the outer circular surface of the stirrup (10) and forming
respective circular arcs, in which channels (11) there are engaged respective inwardly
folded flanges (13) of the end of the upper rear arm (1) of the parallelogram and
which are disposed facing each other, also forming respective circular arcs mating
with the arcs of the peripheral channels (11).