Multiple torsion spring and methods of use

FIELD OF THE INVENTION

The present invention relates to multiple torsion springs. The springs of the present invention may be used in various applications, but are particularly suitable for effecting closure of a throttle valve of a throttle body or carburetor of an automobile internal combustion engine.

BACKGROUND OF THE INVENTION

Use of springs and spring assemblies for effecting throttle valve operation is well known in the art. Reference may be made to Blanchard et al. U.S. Pat. No. 4,582,653, which is incorporated herein by reference, for a more detailed disclosure of a typical throttle body equipped with a spring assembly for returning a throttle valve toward a closed position.

FIGS. 1-3

illustrate a prior art single torsion spring assembly

10

. The spring assembly

10

is described in detail in Pavlin U.S. Pat. No. 5,368,283 which is incorporated herein by reference. The spring

10

is referred to herein as a single torsion spring because it is coiled from a single strand of music wire. Reference is also made to Paggeot U.S. Pat. No. 4,828,235 which describes a similar single torsion spring, and which is also incorporated herein by reference.

The spring assembly

10

is shown in

FIGS. 1-2

in conjunction with a throttle body

11

of an automobile internal combustion engine. The throttle body

11

includes a lever

12

supported to rotate about the axis of a shaft

13

(FIG.

2

). Rotation of the lever

12

in one direction effects opening of the throttle valve (not shown) of the throttle body

11

, while reverse rotation of the lever

12

by the spring assembly

10

effects closing of the throttle valve.

The spring assembly

10

includes a coiled torsion spring

15

having two coils

15

A adjacent each end of the spring and a pair of end bushings

16

and

17

(FIG.

3

). The torsion spring

15

is wound helically from round music wire and is formed with the end coils

15

A being of a reduced diameter. The end coils

15

A of the single torsion spring are of equivalent diameter, albeit reduced from the diameter of intermediate coils. Tangs

24

and

25

extend radially from the coils. One tang is parallel to a longitudinal axis of the spring.

A dual torsion spring, that is a spring comprising two coiled strands, may be produced by coiling the two strands about a coiling shaft (or simply shaft). The dual torsion spring is then slid off of the shaft. Such a shaft wound dual torsion spring is not capable of having two reduced reduce end coils, one on either side of the intermediate coils. Further, one reduced end coil is difficult to achieve via a shaft wound method. These limitations are a result of the fact that a spring wound as such on a shaft cannot be slid off of the shaft after it is formed without deforming it.

Recently dual torsion springs having reduced end coils, wherein the end coils are of equivalent diameters, have become known in the art.

FIGS. 4-7

illustrate such a prior art dual torsion spring

30

. The dual torsion spring

30

has a first end coil

32

and a second end coil

34

separated by intermediate coils

36

. The first end coil

32

has a diameter

38

and the second end coil

34

has a diameter

40

of the same size. Both end coil diameters are reduced in size as compared to a diameter

42

of the intermediate coils

36

.

The dual wound torsion springs shown in

FIGS. 4-7

have been produced utilizing what may be referred to as single-wound technology. Each strand is formed into a coil and then, through post-wind operation, the strands are merged into a dual torsion spring. Heretofore, known manufacturing techniques required each end coil to be of equal diameters. This had certain disadvantages, particularly relevant to shafts of throttles, wherein the shafts had to be over built (or over molded) at one end to accommodate the diameter of an end coil. With reference to

FIGS. 1 and 2

, this would generally require shaft

13

to be over built near lever

12

.

Embodiments of the present invention overcome these and other problems.

SUMMARY OF THE INVENTION

The present invention relates to multiple torsion springs. It more particularly relates to dual torsion springs having dissimilar reduced end coils.

A multiple torsion spring assembly according to the present invention may be provided with a coiled helical dual torsion spring. The spring has first and second end coils, and a plurality of intermediate coils between the first and second end coils. The first end coil inner diameter is less than the inner diameter of the intermediate coils. The second end coil inner diameter is less than the inner diameter of the first end coil.

The multiple torsion spring assembly may be manufactured by supplying at least two strands simultaneously to deflection structure of a type commonly known in the art and deflecting the two strands. The two strands are deflected into a plurality of coils including the first and second end coils and the intermediate coils. The inner diameter of the first end coil is formed smaller than the inner diameter of the intermediate coils. Likewise the inner diameter of the second coil is formed smaller than the inner diameter of the first end coil.

An inventive deflection structure comprising a coiling point assembly is provided herein. The coiling point assembly generally includes a relatively fixed coiling point and a relatively movable coiling point. Preferably two coiling point components are used for dual torsion springs. Each coiling point includes a guide, e.g a groove, for guiding the wires during the coiling process.

The spring may be used to control a throttle return of a throttle body including a lever supported to rotate about an axis of a shaft, and wherein rotation of the lever effects positioning of a throttle valve. The spring is positioned on the shaft to effect rotation of the lever. This includes positioning a tang of one of the end coils to provide a primary source of throttle control. Another tang of the same end coil is positioned to provide a secondary source of throttle control. Other variations using the spring to effect the valve will be apparent to those of skill in the art.

Accordingly, one object of the present invention is to provide a new and improved torsion spring. The intermediate coils shown in

FIG. 13

comprise a portion where the coils taper, in diameter, to form a fructo-conical shape.

Another object of the present invention is to provide a more robust throttle body at a reduced cost.

Another object of the present invention is to provide a more reliable throttle body. A further object is to provide a means for complying with federal standards and regulations requiring system redundancy of select parts.

Another object is to provide improved means and methods for forming springs.

Other objects and advantages of the present invention will be apparent from the following detailed discussion of exemplary embodiments with reference to the attached drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

shows an elevated side view of a prior art spring assembly positioned on a shaft of a throttle body.

FIG. 2

shows an end view of the spring assembly shown in FIG.

1

.

FIG. 3

shows a perspective view of the prior art spring assembly of FIG.

1

.

FIG. 4

shows a perspective view of a prior art dual torsion spring having end coils of identical diameters.

FIG. 5

shows a side view of the prior art spring shown in FIG.

4

.

FIG. 6

shows an end view of the prior art spring shown in FIG.

4

.

FIG. 7

shows a section view of the prior art spring shown in

FIG. 5

cut through section lines

7

—

7

.

FIG. 8

shows a perspective view of a dual torsion spring according to the present invention.

FIG. 9

shows a side view of the spring shown in FIG.

8

.

FIG. 10

shows an end view of the spring shown in FIG.

8

.

FIG. 11

shows a section view of the spring shown in

FIG. 9

cut through section line

11

—

11

.

FIG. 12

shows a section view of a spring having non-uniform intermediate coils.

FIG. 13

shows a pitched spring.

FIG. 14

shows a top view of a coiling point assembly according to the present invention and including a movable coiling point.

FIG. 15

shows a side view of the coiling point assembly shown in FIG.

14

.

FIG. 16

shows an exploded view of the coiling point assembly of

FIG. 14

, and further including a cover plate.

FIG. 17

shows an end view of the coiling end of the coiling point assembly.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The present invention is discussed in relation to dual torsion springs for throttle bodies of automobiles; other uses will be apparent from the teachings disclosed herein. The present invention will be best understood from the following detailed description of exemplary embodiments with reference to the attached drawings, wherein like reference numerals and characters refer to like parts, and by reference to the following claims.

A multiple torsion spring assembly

50

according to an embodiment of the present invention is shown in

FIGS. 8-11

. The spring assembly

50

comprises a coiled helical dual torsion spring

52

having first and second end coils

54

and

56

. A plurality of intermediate coils

58

is located between the first and second end coils

54

and

56

, respectively. Referring to

FIG. 11

, the intermediate coils

58

have an inner diameter

60

and the first end coil

54

has an inner diameter

62

which is less than the inner diameter

60

of the intermediate coils

58

. The second end coil

56

has an inner diameter

64

which is less than the inner diameter

62

of the first end coil

54

. It will be understood that a “dual torsion” spring generally includes two coils, from two respective wire strands, per coil set. And, a “multiple torsion” spring generally includes at least two coils, from respective stands, per coil set.

The intermediate coils

58

shown in

FIGS. 8-11

are of a uniform diameter, but other variations including multiple dimensioned (i.e. non-uniform) inner diameters may be used for some applications.

FIG. 12

depicts a section view of a spring

50

A in which the intermediate coils

58

are non-uniform. Accordingly, the inner diameter

60

would be non-uniform. Further the coils, intermediate and end, may be spaced closely together, as shown in prior art

FIGS. 4-7

, or spaced apart as shown in

FIGS. 8-11

.

In a preferred embodiment, the coiled helical dual torsion spring

52

is adapted to cooperate with a throttle body

11

having a shaft

13

of a predetermined diameter. The second end coil inner diameter

64

is adapted to conform to the shaft predetermined diameter. This eliminates the need for over molding the shaft

13

.

A method of manufacturing the multiple torsion spring assembly

50

may comprise supplying strands of music wire

70

and

72

simultaneously to a deflection structure. The two strands

70

and

72

may be simultaneously deflected into a plurality of coils including first and second end coils

54

and

56

, and intermediate coils

58

between the first and second end coils

54

and

56

. The invention is not limited to wire; suitable alternatives will be apparent to those of skill. The first end coil

54

is formed into an inner diameter

62

smaller than an inner diameter

60

of the intermediate coils

58

. An inner diameter

64

of the second end coil

56

is formed smaller than the inner diameter

60

of the intermediate coils

58

and smaller than the inner diameter

62

of the first end coil

54

. The two strands

70

and

72

may be generally adjacent to one and another as shown in FIG.

9

.

Simultaneous deflection does not require each coil of a given coil set to be of an equal diameter.

FIG. 13

depicts a section view of a pitched multi-torsion spring assembly

50

B. The first end coil

54

is pitched a positive pitch angle alpha (&agr;) relative to a center line CL. The second end coil

56

is shown at a negative pitch angle beta (&bgr;).

The multiple torsion spring

50

may be used to control the throttle return of a throttle body

11

including a lever

12

supported to rotate about an axis of a shaft

13

, wherein rotation of the lever

12

effects positioning of a throttle valve. The spring

50

is positioned on the shaft

13

to effect rotation of the lever

12

. A tang

74

of the first end coil

54

, or second end coil

56

, is positioned to provide a primary source of throttle control. The other tang

76

of the same end coil is positioned to provide a secondary source of throttle control.

Deflection structure used to coil the strands may include, among other devices, coiling points of a coiling machine. Coiling machines are well known in the art and will not be further described.

FIG. 14

shows a top view of a coiling point assembly

100

suitable for manufacturing a dual torsion spring assembly

50

. The coiling point assembly

100

includes a mounting end

102

and a coiling end

104

. Mounting end

102

is mounted to a coiling machine (not shown) with bore holes

106

and

108

.

FIG. 15

shows a side view of the coiling assembly

100

. The coiling point assembly

100

preferably includes a fixed point

10

and a movable point

112

, better seen in FIG.

16

.

FIG. 16

depicts a cover plate

114

for the movable point

112

. It is to be understood that fixed point

110

is not fixed absolutely to the coiling machine; both coiling points are movable to form coils of differing diameters. The movable point

112

is however movable relative to the fixed point

110

.

FIG. 17

shows a partial end view of the coiling end

104

. Grooves

116

and

118

provide means for positioning the strands and for maintaining relative positioning of the strands during the coiling process.

Thus, although there have been described particular embodiments of the present invention of a new and useful Multiple Torsion Spring And Methods of Use, it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following claims.