Economical lifting device-jack stand

CROSS REFERENCE TO RELATED APPLICATIONS

Applications have also been filed directed to an Economical Lifting Device—Trunk Jack, and Economical Lifting Device—Power Unit For Use With A Jack Stand and Lift Bridge, as described in the present specification.

BACKGROUND OF THE INVENTION

The invention relates to a low cost consumer device for lifting and supporting an object i.e. a corner of an automobile; particularly to a low cost consumer jack, and also to a low cost two part jacking system including a power unit that can be used to place and elevate a jack stand. The inventor of the present invention is a pioneer of the two part jacking system holding numerous issued and pending patents for a two part jacking system and related products and processes as described below. All such prior art patents and applications are incorporated herein by reference.

Briefly, the commercial two part jacking system consists of a power unit and a set of separate mechanical jack stands. Examples of the two part jacking system and mobile power unit are described in detail in U.S. Pat. Nos. Re.32,715 and 4,589,630. Some examples of the jack stands are described in detail in U.S. Pat. Nos. 4,553,772; 4,490,264; 5,110,089; 5,183,235 and 5,379,974. The stands are capable of being vertically extended and retracted from the garage floor or road surface and, when extended, can be locked in place at any desired position by a ratchet and pawl assembly. The commercial power unit has a mobile chassis adapted to carry a plurality of the jack stands, and has a pair of lift arms adapted to mate with the outermost jack stand for placement and removal.

In use, the commercial mobile power unit is operated entirely from its handle. It is maneuvered under a vehicle to place a jack stand in a desired location for lift and supporting the vehicle. The power unit is activated from the handle, and this jack stand is then vertically extended to the desired height, thus lift the vehicle on the stand. By operating the controls at the end of the handle, the operator can cause the power unit to disengage from the stand, and the stand will remain locked in its extended supporting position under the vehicle. After the stand is raised and locked in place to support the vehicle or other load in a lifted position, the power unit lift arms are lowered and the power unit is disengaged from the stand and pulled away, leaving the stand in position supporting the load. Another jack stand, carried within the chassis, is automatically transferred to the forward end the chassis for placement at another desired location of the vehicle or for use to lift and support another vehicle.

To lower the vehicle and remove the stand, the power unit is maneuvered to reengage with the stand. The engagement causes any existing jack stands carried within the chassis to be automatically transferred rearward within the chassis. By manually operating a control at the end of the handle, the operator can cause the power unit to reengage with the stand, and to disengage the ratchet locking mechanism of the stand and lower the stand to its original position. The power unit remains engaged with the stand and can be pulled away from the vehicle with the stand carried within the chassis.

The original commercial power units were adapted to carry up to four jack stands within the chassis. Additional jack stands could be purchased and arranged at various stations on the garage floor to reload the power unit, so that a single power unit could be utilized to efficiently place and actuate numerous jack stands. It was found that many commercial users would utilize all of their available jack stands, and the power unit was thereafter useless until another jack stand was available to be extracted and reused. The present inventor developed a slide forward bridge that adapted the power unit to function as a load-lifting jack to more fully utilize the power unit. Co-pending patent applications have been filed on the features of the power unit convertible into a load-lifting device.

Most of the prior art lifting devices, including those of the present inventor, are very rugged “commercial quality” products involving many castings and machined parts that require welding for fabrication and assembly. It would be highly desirable to design and develop the innovative jack systems in a low cost “consumer quality” configuration that involved minimal welding and machining during fabrication and assembly.

In view of the foregoing problems and desirable features of a two part lift and supporting system, it is an object of the present invention to provide a consumer jack and a consumer power unit for use with a consumer jack stand, that can be economically fabricated from sheet metal and steel plate with little or no machining, and can be assembled with little or no welding.

SUMMARY OF THE INVENTION

The foregoing objects are accomplished by an economical jack stand for use with a power unit. The jack stand includes a rectangular base plate with a tubular housing having an upper end and a lower end, with the lower end attached to the base plate and extending vertically therefrom. The housing has a forward side, a rearward side, a left and right side.

The jack stand has a “U” shaped ratchet shaft having an upper end and a lower end, with ratchet teeth on the forward edges thereof, telescopically inserted within the housing and extendable and retractable within the housing. The shaft has a lift collar mounted on the upper end for engagement with the power unit.

The housing has a pair of pawls interconnected by a D-pin, with each pawl adapted to be engagable with a respective tooth of the ratchet shaft. The pin is pivotally attached to flanges at the upper end of the housing. The pin is rotated by an actuating spring that has an upper end attached to the D-pin, and has a generally vertical handle portion, and has a generally horizontal lower portion including a first position indention and a second position indention.

The housing includes a slotted opening adapted to receive the lower portion of the actuator spring whereby the first position indention is engagable with the slotted opening to position the pawls into engagement with the teeth of the ratchet shaft. The second position indention is engagable with the slotted opening to position the pawls into disengagement from the teeth of said ratchet shaft.

The major components of the jack stand are suitably formed from standard sheet metal and metal plate stock with minimal machining and welding required to form or assemble the components. The base plate is suitably stamped from steel plate. The housing is defined by a piece of sheet metal having a flat pattern including the rearward side with the respective sides and flanges all extending outward from the rearward side. The housing can be formed from a single piece of sheet metal that is stamped to form the apertures and the periphery defined by the flat pattern; the flat pattern is further formed by progressive folds of the stamped flat pattern into the sides of the housing without the need for welding. The ratchet shaft can similarly be formed from a flat pattern that is readily stamped and folded into the desired configurations without the need for machining and welding.

BRIEF DESCRIPTION OF THE DRAWINGS

While the novel features of the invention are set forth in the appended claims, the invention will be better understood along with other features thereof from the following detailed description taken in conjunction with the drawings, in which:

FIG. 1

is perspective view of an economical jack in an elevated position;

FIG. 2

is a perspective view of the screw-threaded actuator shaft and sliding block of the jack of

FIG. 1

;

FIG. 3

is a sectional view taken along

3

—

3

of

FIG. 1

;

FIG. 4

is top plan view of a flat pattern of the sheet metal base of the jack of

FIG. 1

;

FIG. 5

is a top plan view of a flat pattern of the sheet metal sliding block of

FIG. 2

;

FIG. 6

is a top plan view of a flat pattern of the sheet metal lifting pad of

FIG. 1

;

FIG. 7

is a perspective view (similar to FIG.

1

), of an economical power unit;

FIG. 7A

a perspective view of a lift bridge, exploded over the forward ends of the lift arms of the power unit of

FIG. 7

;

FIG. 8

is a perspective view of an economical jack stand in an elevated position (and relatively positioned to be loaded into the base of the power unit of FIG.

7

);

FIG. 9

is a sectional view taken generally along

9

—

9

of

FIG. 7

, (however; with the lift arm in the lowered position) showing a track in the lift arm for slideably retaining the lift bridge and with the lift bridge in the slide forward position;

FIG. 10

is a partial sectional view taken along

10

—

10

of

FIG. 9

;

FIG. 11

is a sectional view, similar to

FIG. 9

, showing a jack stand engaged with the lift arm, and the bridge forced rearward away from the forward ends of the lift arm by the jack stand;

FIG. 12

is a top plan view of a flat pattern of a sheet metal base of the power unit of

FIG. 7

(similar to the flat pattern of

FIG. 3

, except having a forward opening for receiving the jack stand of FIG.

8

);

FIG. 13

is an enlarged perspective view of the ratchet shaft and pawl of the jack stand enclosed within

13

—

13

of

FIG. 8

;

FIG. 13

a

is a perspective view, similar to

FIG. 13

, illustrating another embodiment of a jack stand having a semi-cylindrical ratchet shaft operating within a cylindrical housing;

FIG. 14

is a sectional view taken along

14

—

14

of

FIG. 13

; illustrating the spring positioned so that the pawl is engaged with the ratchet teeth of the shaft;

FIG. 15

is a view similar to

FIG. 14

illustrating the spring in the released position and the pawl disengaged from the ratchet teeth, to lower the shaft;

FIG. 16

is a top plan view of a flat pattern view of the base plate of the jack stand of

FIG. 8

;

FIG. 17

is a top plan view of a flat pattern of a sheet metal housing of the jack stand of

FIG. 8

;

FIG. 18

is a sectional view taken along

18

—

18

of

FIG. 8

, showing the jack stand housing attached to the base plate;

FIG. 19

is a top plan view of a flat pattern of a telescopic ratchet toothed shaft of the jack stand of

FIG. 8

; and

FIG. 20

is an exploded perspective view illustrating the components and assembly of the jack stand of FIG.

8

.

DETAILED DESCRIPTION OF THE INVENTION

The economical jack and support systems were conceived for consumer use, and does not incorporate a mobile chassis having wheels or a large handle for maneuvering and operating the system on a daily commercial basis, but rather as a jacking and supporting system that is placed in position for occasional use by a consumer. However, the economical manufacturing processes can be adapted for components and assemblies of commercial products, as well as the consumer products described in the following preferred embodiments. The manufacturing concepts were based upon eliminating the need for expensive machining, castings, and welding; however, the design can advantageously incorporate such processes for unique components and at critical joints without departing from the basic concepts.

Trunk Jack

Referring to

FIGS. 1-3

, a preferred embodiment of an economical lifting device, i.e., consumer automotive trunk jack

20

, is shown having components that are fabricated primarily from sheet metal and metal plate, stamped into a flat pattern that is folded or otherwise formed into the desired configuration, without the need for machining or welding. The jack has a base

22

having a rectangular bottom

24

with a forward end

26

and a rearward end

28

. The base has a rear flange

30

extending upward from the bottom and has a central aperture

32

. The base has side flanges

34

extending upward from the bottom, with each side flange having a reinforced aperture

36

near the forward end and having an increased thickness

38

along the upper portion of the flange providing a longitudinal recess

40

formed along the lower portion on the inner surfaces of the flange.

The base is suitably about 14 inches in length, about four inches in width with the side and rear flanges about 1.5 inches in height, and can be formed of sheet steel having a thickness of about 0.06-inch from a flat pattern that is stamped and folded as discussed later in detail.

The jack is operated by a screw threaded actuator shaft

42

(see

FIG. 2

) having a distal end

44

and a proximal end

46

extending through the aperture

32

of the rear flange

30

. A suitable actuator is a steel shaft about eight inches in length, with a diameter of about one-half inch having machine threads formed along the length of the shaft.

A reinforcing plate

48

, conforming to the shape of the rear flange

30

(about four inches by one and one-half inches) and having a central aperture, is incorporated to support and distribute the lifting forces of the actuator shaft to the flanges of the base. The reinforcing plate can be suitably formed from about 0.125-inch steel plate. In another embodiment, such reinforcement can be provided by additional folded thicknesses of the rear flange; however, for initial production, the reinforcement plate is provided to ensure durability of the device. The reinforcement plate is suitably retained within the base

22

by an inverted “U” shaped flange

50

at the upper edge of the rear flange. The proximal end

48

of the shaft is rotatably retained within the plate and aperture

32

of the rear flange by a bushing

52

, and is further adapted at the proximal tip

54

to be engagable by an external handle to facilitate rotation of the shaft.

The shaft

42

actuates a sliding block

56

having a rectangular bottom

57

that slides along the bottom of the base

22

. The block has side flanges

58

with lower portions

60

slideably retained within the longitudinal recesses

40

of the side flanges

34

of the base. The block has a forward flange

62

and a rearward flange

64

, each having aligned apertures

66

that are threaded to provide a central threaded aperture for receiving the distal end of the threaded actuator shaft. The side flanges are further adapted with apertures

68

for attachment to the lifting mechanism of the jack. The block can be formed from a solid block of metal that is machined, drilled and threaded to provide the desired features, but is preferable formed from 0.188-sheet metal that is stamped into a flat pattern and folded and formed as described later in more detail.

The jack has a pair of lift arms

70

acting in parallel having forward ends

72

and rearward ends

74

, with the rearward ends having apertures therein and pivotally attached at the apertures

68

to the respective side flanges

58

of the sliding block

56

. The lift arms are suitably formed from 0.125-inch steel about 1 inch wide and about 13 inches in length. The lift arms can be produced in large quantity and received directly from the steel mill having the desired dimensions.

The lift arms

70

function with a pair of connecting arms

76

acting in parallel having forward ends

78

pivotally attached at the apertures

36

near the forward ends of the side flanges

34

of the base, and having rearward ends

80

pivotally attached to the respective lift arm at a pivot point

82

. The pivot point is at a distance from the rearward end of the lift arm that is about equal to the length of the connecting arm. The connecting arms are suitably formed from 0.125-inch steel about 1 inch wide and about 5 inches in length, and can also be produced and received in large quantities directly from the steel mill.

As the block

56

is advanced by the actuator shaft

42

, the rearward ends of the connecting arms are rotated upward, and the lift arms are rotated about the pivot point

82

at the rearward ends of the connecting arms, to elevate the forward ends of the lift arms vertically above the forward end

26

of the base

22

.

The lift arms

70

further include a lifting pad

84

mounted on the forward ends

72

to engage the object to be lifted. The lifting pad includes an upper rectangular plate

86

oriented horizontally and having a pair of parallel lever arms

88

extending downward and forward from the sides of the plate, at an angle of about 30 degrees, with each lever arm having a lower end

90

and having an upper end

92

pivotally attached to the forward ends of the lift arms. The lifting pad is suitably formed from steel about 0.188-inch thick, with the upper plate about 1.5 inches by 4 inches, with the lever arms about 0.5-inch by 3 inches; and is produced from a stamped flat pattern (see

FIG. 6

) with the lever arms folded downward 90 degrees. The lifting pad preferably includes a central threaded aperture

93

for receiving a screw-out saddle

94

; or the plate can utilize a sleeved nut (not shown) swedged within the aperture for alternative threaded support for the saddle.

The screw-out saddle

94

includes a threaded shaft

96

about 0.5-inch in diameter and extending downward about 4 inches, and engaged within the aperture

93

of the lifting pad. The screw-out saddle is utilized to adjust the distance between the lifting pad and the object to be lifted for maximum lift and utility of the jack.

The upper plate

86

of the lifting pad

84

is retained in the horizontal orientation by a pairs of connecting links

98

pivotally connected to the lower ends

90

of the lever arms

88

and pivotally connected to a point

100

on the connecting arms, so that the lifting pad remains substantially horizontal during movement of the lift arms.

Referring now to

FIG. 4

, the base

22

is preferably formed from a piece of sheet metal having a flat pattern defining the areas of the rectangular bottom (

24

) and the respective rear flange (

30

), side flanges (

34

). The pattern includes additional flange areas for forming the increased upper portion (

38

) of the side flanges, additional tabs

102

for reinforcing the areas around the apertures (

36

,

36

A) in the side flanges, a reinforcing tab

104

at the rearward end of the side flanges, and two tabs (

50

) for reinforcing the rear flange, all extending outward from the rectangular bottom. The entire base can be formed from a single piece of sheet metal that is stamped to form the apertures and the periphery defined by the flat pattern.

The flat pattern of the base

22

can include one or more optional locking tabs

104

A that extend from the reinforcing tabs

104

(at the rear of the side flanges) that can be inserted into optional corresponding slots

30

A in the rear flange (

30

). After the flanges are folded and formed as detailed below, the locking tabs can be inserted through the slots and folded over to lock the corners of the rear and side flanges of the base.

The base is further formed by progressive folds of the stamped flat pattern, having first folds along

106

at the upper edge of the side flanges folded inward 180 degrees thereby providing a double thickness of sheet metal around the apertures

36

near the forward end of each side flange and forming a double thickness along the upper portion

38

of the side flange whereby the longitudinal recess

40

is provided by the single thickness along the lower portion of the side flange.

The outer two tabs (

50

) at the rear flange of the base are each folded along

108

and

110

inward 90 degrees to form the upper edge

50

of the rear flange. The base of the rear flange is folded along

112

inward 90 degrees to form the rear flange

30

, and along

112

A (a metal thickness rearward from fold

112

) to form the reinforcing tabs

104

at the rearward end of the side flanges (for reinforcing the rear flange.) The base of the side flanges are then folded along

114

upward 90 degrees to form the side flanges

34

and the reinforcing tabs

104

to enclose the rear flange to form the base

22

. (The optional locking tabs

104

A can then be folded 90 degrees inward and inserted through the slots

30

A, and folded another 90 degrees to further lock the rear corners, without the need for welding.)

Referring now to

FIG. 5

, the sliding block (

56

) is preferably formed from a piece of 0.188-sheet steel having a flat pattern defining the areas of the rectangular bottom (

57

) and the respective forward flange (

62

), rearward flange (

64

), and side flanges (

58

) extending outward from the rectangular bottom. The entire block can be formed from a single piece of sheet metal that is stamped to form the apertures

66

and

68

and the periphery defined by the flat pattern. The apertures are suitably threaded to match the threads of the actuator shaft

42

.

The block is further formed by progressive folds of the stamped flat pattern, having first folds along

116

at the side flanges with the upper portion folded downward 90 degrees, then the lower portion is defined by folds along

118

of 90 degrees upward, and the side flange is fully formed by another 90 degree fold upward along line

120

. The forward flange(

62

) is then folder along line

122

upward 90 degrees, and the rear flange (

64

) is folded along

124

upward 90 degrees to complete the block.

Referring to

FIG. 6

, the lifting pad (

84

) is similarly formed from a piece of 0.188-inch sheet steel having a flat pattern defining the areas of upper rectangular plate (

86

) and the respective lever arms (

88

). The flat pattern includes the respective apertures formed in the upper plate and the upper ends (

92

) and lower ends (

90

) of the lever arms. The entire lifting pad can be formed from a single piece of sheet metal that is stamped to form the apertures and the periphery defined by the flat pattern. The threads (for the shaft of the screw-out saddle) are tapped into the central aperture, and folds along

126

, 90 degrees downward, fully form the lifting pad.

The various flat patterns may incorporate allowances for bend radii, corner termination apertures and other metal forming techniques, and some hammering to finalize the configuration. The other components can be formed very economically, especially in large quantities, from stamped and folded sheet metal and can be fully assembled without the need for machining and welding.

Power Unit/ With Slide Forward Bridge

Referring now to

FIGS. 7-8

and

12

, an embodiment of an economical power unit

128

is adapted for use with an economical jack stand

130

. The jack stand (see

FIG.8

) has a base plate

132

with a housing

134

extending upward from the base plate and having a ratchet shaft

136

telescoped within the housing, with a lift collar

138

at the upper end of the shaft. The power unit has many components, similar to the components of the trunk jack

20

, fabricated without machining or welding and is similarly assembled without the need for welding (as previously described in terms of FIGS.

1

-

6

). After the power unit has been used to place the jack stand(s), the power unit can additionally be adapted, with a lift bridge

139

(see FIG.

7

A), for use as a conventional jack as discussed later in detail.

The power unit

128

has a base

140

(similar to base

22

of

FIGS. 1 and 4

) having a rectangular bottom

24

′, the rear flange

30

′ with central aperture

32

′, the side flanges

34

′ with reinforced apertures

36

′ and increased thickness

38

′ along the upper portion thereof providing the longitudinal recess

40

′ formed along the lower portion on the inner surfaces of each side flange, as previously discussed. However, the base of the power unit includes a “U” shaped opening

141

in the forward end thereof for receiving the jack stand

130

, by sliding over the base plate

132

and engaging the bottom of the housing

134

within the opening. The U-opening includes a pair of optional lead-in tabs

142

inclined upward (for sliding over the base plate), and a lip

143

flared upward (see

FIG. 12

) to facilitate engagement with the jack stand.

In a basic embodiment, the power unit utilizes the same lift arms (

70

), connecting arms

76

′, and connecting links

98

′ as previously described (in terms of the jack

20

). However, the power unit must have an opening at the forward ends of the lift arms to receive and engage the lift collar

138

of the jack stand

130

; therefore, a pair of separated leveling pads

144

are utilized (rather than the lifting pad

84

, utilized by the jack) at the forward ends of the lift arms.

Referring also to

FIGS. 9-11

, a preferred embodiment is shown having lift arms

156

that include an upper track to slideably retain the lift bridge

139

on the lift arm. The lift arms are shown in the horizontal position, and the upper tracks uniquely cooperate with the respective leveling pad

144

of the lift arms to retain and transfer the lift bridge. The leveling pads are suitably formed from a rectangular plate of about 0.188-inch steel, in a vertical orientation having the upper edge extruded, folded or wiped to form an outward flange

146

and provide a smooth upper surface

148

about 0.250-inch wide. The upper surface of the leveling pad is used to engage the lift collar

138

of the jack stand (see FIG.

11

), or to engage the lower surface of the bridge

139

(see FIGS.

9

and

10

). Each leveling pad includes a lever arm

150

extending forward and downward, at about 30 degrees, having a lower end

152

, and an upper end

154

pivotal attached to the forward end of the lift arm. The pair of connecting link

98

′ (see

FIG. 7

) are each pivotally connected at one end to the lower end

152

of the lever arm and pivotally connected at the other end to connecting point

100

′ on the respective connecting arms

76

′, as previously discussed.

The power unit is operated (same as jack

20

, see

FIG. 2

) by the screw threaded actuator shaft

42

and the reinforcing plate

48

, and the sliding block

56

that slides along the bottom of the base

140

. As previously discussed, the block is preferable formed from sheet metal that is stamped into a flat pattern and folded into the desired configuration (see FIG.

5

).

In this preferred embodiment, the power unit has the pair of lift arms

156

acting in parallel having forward ends

158

and rearward ends

160

, with the rearward ends pivotally attached to the respective side flanges

58

of the sliding block

56

. Each lift arm further includes the upper track provided by a longitudinal recessed channel

162

formed in the upper edge thereof for slideably retaining the lift bridge

139

. The channels can suitably be formed into a substantially circular (see

FIG. 10

) “C” or “U” shaped cross section. The lift arms are suitably formed from 0.125-inch steel about 1 inch high (after forming the channel) and are about 13 inches in length. The lift arm, including the channels, can be formed at the steel mill by folding and forming the upper edge, or extruding the upper edge into the desired shape in long strips and cutting them to the desired length. The cross section of the lift arm

156

are symmetrical and the same formed lift arm stock can be use for the left lift arm and reversed for the right lift arm. The lift arms can be efficiently and economically produced in large quantities and received directly from the mill, ready for assembly.

The lift bridge

139

is primarily a rectangular plate that is adapted to be positioned on the forward ends

158

of the lift arms

156

. The forward ends of the lift arms include the leveling pads

144

, each having the flange

146

and the upper surface

148

adapted to engage the lift collar

138

of the jack stand, and are also adapted to engage the flange channels

164

in the inner sides of the bridge, when the bridge is properly positioned on the forward ends of the lift arms. The lift bridge

139

is efficiently produced by a metallic casting incorporating the desired recesses and flanges, as well as any other desired features, i.e. a central aperture therein with suitable reinforcing boss, or strengthening ribs or gussets for added strength or for other specific applications.

The recessed channels

162

of the guide tracks each have a suitable shape and internal surface to retain a follower member

166

. As shown in

FIG. 10

, the follower member has a suitable inverted “T” cross section retained within the “C” shaped recessed channels

162

, and has a guide pin

168

with a “T” shaped upper end, extending upward from the opening of the channel and is adapted to traverse along the upper surface of the lift arm. The bridge

139

further includes a pair of recessed slots

170

in the rearward bottom thereof adapted to engage the guide pins, to facilitate movement of the lift bridge along the track from the forward position to the displaced position. The inverted “T” shape of the follower member and the “T” shape of the guide pin form a generally “I” shaped cross section of the follower member to suitable interconnect the bridge within the recessed channel.

The bridge

139

is retained by the engagement of the guide pins of the follower member

166

and the recessed slots

170

whenever the bridge is displaced rearward along the lift arm. When the bridge is transferred to the forward end of the lift arms, the channel flanges

164

of the bridge slide over the flanges

146

of the leveling pads

144

until the bridge is fully positioned thereon. This follower member, guide pin, recessed slot, retention means are designed to operate with loose tolerances, and is rugged and reliable in the work environment. With the foregoing components, the lift bridge remains integral with the lift arms and functions quite smoothly from the forward position to the rearward displaced position on the lift arms of the power unit.

The length of the longitudinal recessed channel

162

of the lift arm

156

is defined by a plug

172

that is adapted to fit snugly within the recessed channel. The plug is first inserted into the forward end of the recessed channel and pushed to the desired position, then the exterior of the track is staked (i.e. with a hammer and punch) at, or slightly rearward of, the plug to fix it into position within the channel. The follower member

166

is thereby limited to travel along the lift arm between the forward end thereof and the displaced position defined by the position of the plug.

Referring particularly to

FIGS. 9 and 11

, a more preferred embodiment is described wherein the recessed channels

162

further include biasing means, shown as compression springs

174

to urge the respective follower members

166

to the forward ends of the channels of the lift arms. Thus, the lift bridge

139

is automatically urged to the forward ends of the lift arm; and conversely, a force on the forward end of the lift bridge pushes the respective follower member rearward within the recessed channel to compress the spring. The compression spring is adapted to provide sufficient force to position the bridge at the forward ends of the lift arms (when the lift arms are in a generally horizontal orientation), and further adapted to be readily compressible by the routine engagement of the forward end of the bridge with the housing or lifting pad of a jack stand

130

within the forward end of the frame. The springs

174

are suitably inserted into the channels

162

at the forwards end thereof, prior to insertion of the respective follower member

166

. The spring and follower member are suitable retained at the forward end of the lift arms by the engagement of guide pin with the bridge, but can be further contained by blocking the forward end of the recessed channel with a suitable plug, crimp or other restriction.

The spring

174

is retained within the recessed channels

162

and automatically expanded to the full span of the channel along with the follower members

166

, whenever there is no jack stand

130

positioned within the frame of the power unit, as in FIG.

9

. The power unit, with the automatic slide forward bridge

139

positioned at the forward ends of the lift arms

156

, is thus automatically converted for use as a load-lifting jack.

The springs

172

are shown compressed within the channels in

FIG. 11

, by the engagement of the jack stand. The power unit, with the automatic slide forward bridge forced rearward by the engagement of a jack stand, is thus automatically converted for use with the jack stand.

The lift bridge

139

further features a screw-out saddle

176

that includes a threaded shaft

178

about 0.5-inch in diameter and extending downward about 4 to 6 inches, and engaged within a threaded aperture of the bridge. The screw-out saddle is utilized to adjust the distance between the bridge and the object to be lifted for maximum lift and utility of the power unit.

Referring now to

FIG. 12

, the base

140

is preferably stamped from a piece of sheet steel having a flat pattern defining the areas of the rectangular bottom (

24

′) including the U shaped opening

141

and the lip

143

and the respective rear flange (

30

′) and side flanges (

34

′). The pattern includes additional flange areas for forming the increased upper portion (

38

′) of the side flanges, additional tabs

102

′ for reinforcing the areas around the apertures (

36

′,

36

A′) in the side flanges, a reinforcing tab

104

′ at the rearward end of the side flanges, and two tabs (

50

′) for reinforcing the rear flange, all extending outward from the rectangular bottom. The entire base can be formed from a single piece of sheet metal that is stamped to form the apertures and the periphery defined by the flat pattern.

The flat pattern of the base (

140

) can include one or more optional locking tabs

104

A′ that extend from the reinforcing tabs

104

′ (at the rear of the side flanges) that can be inserted into optional corresponding slots (

30

A′) in the rear flange (

30

′). After the flanges are folded and formed as detailed below, the locking tabs can be inserted through the slots and folded over, to lock the corners of the rear and side flanges of the base.

The base is further formed by progressive folds of the stamped flat pattern, having first folds along

106

at the upper edge of the side flanges folded inward 180 degrees thereby providing a double thickness of sheet metal around the apertures

36

near the forward end of each side flange and forming a double thickness along the upper portion

38

of the side flange whereby the longitudinal recess

40

is provided by the single thickness along the lower portion of the side flange.

The outer two tabs (

50

) at the rear flange of the base are each folded along

108

and

110

inward 90 degrees to form the upper edge

50

of the rear flange. The sheet is folded along

112

inward 90 degrees to form the rear flange

30

, and along

112

A (a metal thickness rearward from fold

112

) to form the reinforcing tabs

104

at the rearward end of the side flanges (for reinforcing the rear flange.) The base of the side flanges are then folded along

114

′ inward (upward) 90 degrees to form the side flanges

34

and the reinforcing tabs

104

′ and locking tabs

104

A′ to enclose the rear flange, to form the base

140

without the need for welding.

Referring again to

FIG. 5

, as previously discussed, the sliding block (

56

) is preferably formed from a piece of 0.188-inch sheet metal having a flat pattern defining the areas of rectangular bottom (

57

) and the respective forward flange (

62

), rearward flange (

64

), and side flanges (

58

) extending outward from the rectangular bottom. The entire block can be formed from a single piece of sheet metal that is stamped to form the apertures

66

and

68

and the periphery defined by the flat pattern. The apertures are preferably threaded to match the threads of the actuator shaft.

The block is further formed by progressive folds of the stamped flat pattern, a having first folds along

116

at the side flanges with the upper portion folded downward 90 degrees, then the lower portion is defined by folds along

118

of 90 degrees upward, and the side flange is fully formed by another 90 degree fold upward along line

120

. The forward flange (

62

) is then folder along line

122

upward 90 degrees, and the rear flange (

64

) is folded along

124

upward 90 degrees to complete the block.

Jack Stand

Referring now to FIGS.

8

and

13

-

20

, an economical jack stand

130

(for use with the power unit

128

), is shown that is extremely functional, reliable, durable and safe; and the components thereof can be produced and assembled without machining or welding. The jack stand is typically operated by the power unit

128

; however, the jack stand can be utilized separately, placed and operated by hand, to support a load that has already been elevated by a conventional jack or other means.

The jack stand

130

, and many components thereof have been previously described in reference to the power unit

128

, and includes the rectangular base plate

132

having the tubular housing

134

extending vertically from the base plate.

The base plate

132

(see particularly

FIGS. 16-18

) is suitable a rectangular square about 6 inches by 6 inches of 0.125-inch steel plate that is stamped to include about four slots

180

therein (adapted to receive tabs

182

from the lower ends of the tubular housing). The peripheral area

183

of the base plate is flat, and the central area of the base plate (inscribed by the slots) is flat to support the tubular housing, and the central area is contoured upward about 0.125-inch through a formed area

184

to provide clearance for the tabs of the tubular housing to be folder under the base plate.

The tubular housing

134

(see particularly

FIGS. 17 and 20

) extends about six to eight inches from the base plate and is preferably rectangular in cross section having a rear side

186

, a left side

188

, a right side

190

, a left front half

192

, a right front half

194

, with each side about 2 inches wide. The housing has an upper end

196

and a lower end

198

. The lower ends of the respective sides include the extended tabs

182

, adapted to be inserted into the slots

180

and folded under the base plate

132

, for attaching the housing to the base plate. The lower ends of the left side

188

and right side

190

of the housing each further includes a lateral protrusion

200

formed initially by a stamped slit of about 0.75-inch and progressively pressed outward about 0.125-inch to provided a suitable channel (with the base plate

132

) for slideable engagement with the lip of the U shaped opening

141

of the base of the power unit

128

. The left and right sides of the housing further include vertical slots

202

, in the centers thereof, which act as stabilizing guides for the ratchet shaft

136

, to be described later in more detail. The housing is suitably formed from 0.125-inch steel that is progressively stamped, formed and folded into the desired configuration.

The ratchet shaft

136

(see particularly

FIGS. 19 and 20

) is preferably a “U” shaped shaft having an upper end

204

, a lower end

206

, with upward-inclined-ratchet teeth

208

formed on the forward edges thereof. The shaft is suitably about seven inches long and formed of 0.188-inch steel with equal sides (about 1.88 inches) adapted to be telescopically inserted within the housing

134

, and is vertically extendable and retractable within the housing. The upper end

204

of the ratchet shaft includes upper tabs

210

that are folded inward 90 degrees to provide an upper surface, and the upper tabs include four apertures

212

, for attaching the lift collar

138

to the upper end of the shaft. The lower end

206

of the sides includes optional tabs

214

which are folded inward to provide additional strength and rigidity to the lower end of the shaft. The left and right sides of the shaft also include stamped and threaded apertures

215

that, upon assembly, are aligned with the vertical slots

202

of the housing and are adapted to retain stabilizing lugs

242

, to be later described in more detail.

The tubular (square) housing

134

and (“U”) ratchet shaft

136

are preferably generally rectangular in cross-section, as shown in

FIG. 13

, and have strength and self aligning advantages. However, as shown in

FIG. 13

a

, the components could also be formed having a cylindrical housing

134

a

and a semi-cylindrical shaft

136

a

and a generally circular cross-section that can similarly be readily stamped rolled, and formed into an economical jack stand of the present invention.

The height of the ratchet shaft

136

is locked in position within the housing by a pair of pawls

216

that are interconnected on a D-pin

218

and each pawl is adapted to be engagable with a respective tooth

208

of the shaft. Each pawl is somewhat “claw” shaped having a base with a diameter of about 0.50-inch and tapering about one inch to a curved, sharp distal tip. The D-pin has a “D” shaped cross-section that mates with corresponding lateral “D” shaped apertures in the pawls, to fix the orientation of the pawls on the D-pin. The D-pin suitably has a major diameter of about 0.375-inch of hardened steel and is about 2.25 inches in length. Each pawl is suitably stamped from 0.25-inch steel plate. The pawls are aligned on the pin adjacent the ratchet teeth and suitably fixed laterally on the D-pin with setscrews, or preferably swedged, staked or are otherwise bonded to the pin. The upper end of the housing includes a pair of vertical flanges

220

extended forward about one inch and having apertures

222

therein to pivotally support the D-pin adjacent to the ratchet shaft. The flanges are further extended and folded inward to provide a front portion

224

to generally enclose the D-pin and pawls.

The engagement and disengagement of the pawls

216

with the ratchet teeth

208

are controlled by an actuating spring

226

. The upper end

228

of the actuating spring is formed into a “D” shape and attached to (wrapped around) the D pin

218

, and a generally vertical central portion

230

provides the lever handle to control the rotation of the D-pin and pawls. The lower end of the actuating spring in bent generally horizontal (forming a finger pull loop) and includes a first position indention

232

and a second position indention

234

. The actuating spring is suitable formed of 0.125-inch diameter spring steel, or flat spring steel about 0.125-inch by about 0.063-inch, (about six inches long) and contoured generally into the above described shape with a handle central portion

230

about three inches in length.

A front half (shown in the right front half

194

) of the housing

143

includes a slotted opening

236

adapted to receive the lower end of the actuating spring

226

. The slot is off center to provide any needed clearance with a screw out saddle that may be extended downward within the center of the ratchet shaft

136

. The upper end

228

of the actuating spring

226

is similarly positioned on the right side of the D-pin (near the right pawl

216

) to vertically align the actuating spring in the slotted opening

236

.

As shown in

FIG. 14

, when the handle portion

230

of the actuating spring

226

is pulled out, the first position indention

232

is engaged with the slotted opening

236

of the housing, to provide inward (clockwise) rotational torque on the pin

218

, and thus the pawls

216

are each engaged with one of the respective ratchet teeth

208

. In typical ratchet movement, as the ratchet shaft is extended, the inclined upper surface of the next ratchet tooth

208

wedges the underside of the pawl (slightly counter-clockwise) and slides upward past the pawl, and the torque of the spring engages the pawl back onto the “next” tooth, etc. However, the lower surface of the “next” tooth is flat (and indented) and can only act on the upper side of the pawl, and any downward force on the upper side of the pawl tends to lock the pawl into the base of the “next” tooth; and thus prevents any downward movement of the shaft. When the jack stand is raised to the desired height, each pawl is engaged under the adjacent “next” ratchet teeth to securely and safely support the load, and the power unit

128

can be lowered and removed.

As shown in

FIG. 15

, to lower the ratchet shaft, the handle portion

230

of the actuating spring

226

is pushed inward, and the second position indention

234

is engaged with the slotted opening

236

of the housing to provide outward (counter-clockwise) rotational torque on the pin

218

, and thus the pawls

216

are disengaged from the ratchet teeth

208

. It should be noted that, if there is a downward load on the ratchet shaft, the torque of the actuating spring is insufficient to disengage the pawls and the ratchet shaft remains locked within the housing until the load is released (by engagement of the power unit

128

and slightly raising the jack stand), then the torque of the actuating spring releases the pawls and the load and jack stand can be lowered by the power unit.

The lift collar

138

is suitable a rectangular plate having a pair of channels

237

in the lower surface thereof adapted to engage the leveling pads

144

of the power unit

128

. The lift collar has four apertures

238

therein aligned with the apertures

212

in the upper surface of the ratchet shaft

136

, for attaching the lift collar with suitable headless rivets

240

. The lift collar preferably includes a central aperture

241

adapted to receive a screw-out saddle

244

. The lift collar is suitably about 3.5 inches by 2.0 inches and formed of 0.250-inch steel plate, or can also be efficiently cast in the above dimensions to include the channels and the central aperture.

The screw-out saddle

244

is similar to those previously described, having a threaded shaft about 0.50-inch in diameter and about four six inches in length. The screw-out saddle is utilized to adjust the distance between the lift collar and the object to be lifted, for maximum lift and utility of the jack stand.

Referring again to

FIGS. 16-20

, the jack stand is economically produced by first stamping the contoured base plate

132

(see FIG.

16

).

The tubular housing

134

is formed from a piece of sheet metal having a flat pattern (see

FIG. 17

) defining the area of rear side (

186

) in the center thereof, with the area of the left side (

188

) and right side (

190

) extending outward therefrom, and the respective areas of one half of the front sides (

192

,

194

), flanges (

220

,

224

), and tabs

182

each extending outward from the respective side. The periphery of the flat pattern is stamped, along with the lateral protrusions

200

and the vertical slots

202

and apertures

222

. The flat pattern (

134

) is next folded 90 degrees inward along lines

246

, then along lines

248

, and also along lines

250

to form the tubular housing. The metal is stamped and formed with conventional tooling and metal forming techniques, and can be suitably formed with various sequences of the folds.

The tabs

182

of the housing

134

are fully inserted into the corresponding slots

180

in the base plate

132

(see

FIG. 20

) and folded over (see

FIG. 18

) to firmly secure the housing to the base plate.

The pawls

216

, D-pin

218

and actuating spring

226

(see

FIG. 20

) are sub-assembled, with one pawl (i.e. the right) and the actuating spring fixedly positioned on the right side of D-pin, and with the other pawl (i.e. the left) slideably on (but not fixed on) the D-pin. The left end of the D-pin, with the slideable pawl inward, is fed under the front portion

224

of the housing and inserted through the left aperture

222

of the left flange

220

of the housing

134

, and the other end of the D-pin is maneuvered into the right aperture of the corresponding right flange of the housing. The D-pin is then aligned to position the fixed right pawl against the inner right flange

220

(for proper alignment with the respective ratchet teeth

208

of the U shaft to be inserted in the housing) and the slideable pawl (the left) is then positioned close to the inner left flange

220

(for proper alignment with the other ratchet teeth of the shaft), and is fixed in position on the D-pin. The lower end of the actuating spring is then inserted into the opening

236

of the housing, and pushed inward to the 2

nd

position indentation

234

to complete the assembly of the tubular housing.

The U shaped ratchet shaft

136

is stamped into the flat pattern (see

FIG. 19

) and is then folded inward 90 degrees along lines

252

to provide the top and bottom surfaces, then folded inward 90 degrees along lines

254

to form the respective sides of the shaft.

As previously discussed, the lift collar

138

is attached to the upper surface of the ratchet shaft (see

FIG. 20

) by a set of four headless rivets

240

that are inserted within the respective aligned apertures

212

of the ratchet shaft and apertures

238

of the lift collar. The rivets (and apertures) are about 0.125-inch in diameter and are about 0.50-inch in length (exceeding the thickness of the combined components) and are then compressed (hot upset process) to expand within the apertures, and securely bond the lift collar to the upper surface of the shaft. The screw-out saddle

244

in then inserted into the lift collar to complete the assembly of the ratchet shaft.

The assembled ratchet shaft

136

(with lift collar

138

) is then inserted into the housing

134

and nested in the bottom of the housing. A stabilizing lug

242

is attached through the vertical slot

202

in each side of the tubular housing, to the threaded apertures

215

in each side of the ratchet shaft, with suitable fasteners

256

. The lugs are each about 0.25-inch thick by 0.75-inch high by 0.25-inch wide, and are adapted to slide within the full range of the slots to retain and stabilize the ratchet shaft within the housing.

In use by a consumer, the power unit

128

and jack stand

130

are engaged and positioned at a desired lift location under an automobile (or other object to be lifted or pushed). The actuator shaft

42

and block

57

are advanced to pivot the lift arms and raise the leveling pads

144

under the lift collar

138

. This extends the telescopic ratchet shaft

136

from within the housing

134

of the jack stand to raise the automobile corner to the desired height. The power unit can then be lowered and removed, leaving the extended ratchet shaft locked, by a releasable pawls

216

, to the housing of the jack stand, safely supporting the elevated corner of the automobile. (The power unit can now be used to position another jack stand

130

, or used with the bridge

139

as a jack to raise another corner of an automobile.) To lower the automobile, the power unit is re-positioned and re-engaged with the elevated jack stand. The power unit is actuated so that the leveling pads are raised up under the lift collar of the jack stand to support the load and relieve the force on the ratchet shaft. The actuating spring

226

of the jack stand is pushed in to release the pawls from the ratchet shaft, and the actuator

42

and block are retracted to lower the leveling pads of the power unit. As the power unit is lowered, the ratchet. shaft is smoothly telescoped back within the housing until the jack stand is free from the automobile. The jack stand and the power unit can now be removed.

While specific embodiments and examples of the present invention have been illustrated and described herein, it is realized that modifications and changes will occur to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover all such modifications and changes as fall within the spirit and scope of the invention.

Number	Name	Date	Kind
780979	Correll	Jan 1905	A
2895704	Urbain et al.	Jul 1959	A
4005850	Myers et al.	Feb 1977	A
4141526	John	Feb 1979	A
4553727	Arzouman	Nov 1985	A
4556163	Lundman	Dec 1985	A
4856747	Gano	Aug 1989	A
5180131	Few	Jan 1993	A

Economical lifting device-jack stand

Information

Patent Number

Date Filed

Date Issued

Inventors

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

US Referenced Citations (8)