US3191138A

US3191138A - Grid resistor structure

Info

Publication number: US3191138A
Application number: US278871A
Authority: US
Inventors: David C Wycoff
Original assignee: Harnischfeger Corp
Current assignee: Harnischfeger Corp
Priority date: 1963-05-08
Filing date: 1963-05-08
Publication date: 1965-06-22
Anticipated expiration: 1982-06-22

Description

June Z2, 1965 c, w c

GRID RESISTOR STRUCTURE Filed May 8, 1963 2 Sheets-Sheet l NN I; .r M L. W a

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United States Patent 3,191,138 GI-ill REEISTUR STRUQTURE David C. Wyeofii, Broohfieid, Wis, assignor to Harnischfeger Corporation, Milwaukee, Wis. Filed May S, 1%3, Ser. No. 273,871 9 Eliairns. (Qi. assear This invention relates to a resistor and more particularly to a resistor structure predicated upon a helical ribbon twist design.

Basically, the novel resistor structure comprises a grid which is formed from a resistive element twisted into a helical ribbon. Grids of this nature could be stacked in a bank and connected in series or parallel as desired by welding or clamping adjacent terminating ends of each grid together, with insulation means as required. Preferably, the helical ribbon twist grid is formed from a continuous strip of resistive material which is twisted into a first helical ribbon twist portion and is then bent backwards upon itself for twisting into a second helical ribbon twist portion. The said portions are parallelly aligned in intermeshing but non-contiguous relationship. In accordance with the invention, it is possible to multiply this basic conception into all three spatial dimensions whereby a bank of stacked and intertwined helical ribbon twist resistors may be formed.

It is an object of this invention to provide a novel resistor structure chmacterized by interrneshed helical ribbon twist portions.

It is another object of this invention to provide a resistor structure which exhibits enhanced ligidityg compaction; and heat dissipating characteristics.

it is another object of this invention to provide a resistor structure which may be simply and expeditiously formed in an economical fashion.

It is yet another object of this invention to provide a resistor structure characterized by a large surface area per unit length whereby turbulence is induced in the movement of air about the resistor structure.

It is still another object of this invention to provide a resistor structure which is adapted for two or for three dimensional design over a whole range of series; parallel; or series-parallel interconnections.

These and other objects, advantages, and features of the subject invention will hereinafter appear, and, for purposes of illustration, but not of limitation, exemplary embodiments of the subject invention are shown in the appended drawings, in which:

FIGURE 1 is a top plan view of a first embodiment of the invention predicated upon two helical ribbon twist portions;

FIGURE 2 is a front elevational view of the structure shown in FIGURE 1;

FIGURE 3 is an end elevational view of the structure shown in FIGURE 1, taken along the line 3--3 thereof;

FIGURE 4 is a schematic plan view of a bar of resistive material which may be suitably bent and fashioned into the structure shown in FIGURES l3;

FIGURE 5 is a sectional view taken along the line 5--5 of FIGURE 2; 1

FIGURE 6 is a top plan view of a second embodiment of the invention showing a continuous one piece grid resistor provided with four parallelly aligned helical ribbon twist portions; and

FIGURE 7 is a front elevational view of two sets of resistor structures of the type shown in FIGURE 6 mounted in stacked vertical alignment.

In its simplest form, the subject invention is exemplified by the dual helical ribbon twist structure 2 shown in FIGURES 1-3. A bar 4 of suitable resistive material (such as resistor alloy materials ofthe nickel-chromium June 22, 1965 or stainless steeltype) is suitably bent and twisted to form the structure shown in FIGURE 1. The bar 4 is rectangular in shape and comprises a front face F, a rear face R, a top edge T, and a bottom edge B. The F, R, T, and B reference character designations are utilized hereinafter to designate these respective surfaces of the helical ribbon twist resistors.

As shown in FIGURE 1, a first tab portion 3 of the bar 4 defines one end of the resistor structure 2. The bar 4 is twisted to define the helical ribbon twist portion 6, which extends from the tab portion 3. The bar is then bent into a U-shaped bridge member 8. The bridge member d has a channeled cross section as indicated by the concave base It which defines the trough space 12 in between the side flanges l4 and 1d. The bar 4 is again twisted to form a similar ribbon twist portion 18 which extends from the bridge member 3 in parallel alignment and in intermeshing but non-contiguous relationship with the first helical ribbon twist portion 6. The bar 4 then terminates in a tab portion 29 which is aligned with the initial tab portion 3, as best indicated in FIGURE 1.

Means are provided on each of the tab portions 3 and 2% for connecting the resistor structure 2 to a suitable source of electric potential. In the described embodiment, these means are illustrated schematically by the weld joints tl and 92 which are respectively positioned [on the tab portions 3 and 20. As indicated in FIGURES 1 and 2,

suitable leads

22 and 24 are attached to the weld joints 9t) and 92 respectively in order to effectuate the desired connection to the said source of electric potential. If desired, another point for electrical connection can be provided :on the bridge member 8, as indicated by the Weld joint 91, shown in FIGURES 1-3.

With the described connection points 9t992, it is possible to achieve a variety of electrical connections. For example, a potential impressed across the points 99-92 will energize the resistive helical

ribbon twist portions

6 and 18 in series. Likewise, an electrical potential impressed across the points 9 3-91 will energize the helical ribbon twist portion 6, and an electrical potential irripressed across the points it-92 will energize the helical ribbon twist portion 18. Furthermore, when the points and 92 are suitably interconnected, a potential may be impressed across the said common points9-92 and the point 91, such that the helical

ribbon twist portions

6 and 18 may be energized in parallel.

It should be apparent that the arrangement shown in FIGURE 1 provides for horizontal stacking of similar helical ribbon twist portions (such as the

portions

6 and 18, which are horizontally stacked in the plane of the FIGURE 1 drawing). If desired, identical resistor structures 2 could be horizontally stacked in the plane of the FIGURE 1 drawing to any desired extent. Also, the individual helical ribbon twist portions could be axially extended or diminished as desired. In actual practice, the twist dimensions will vary dependent upon operating characteristics which are desired. In commercial embodiments, the resistor structure 2 would not have as many twists per unit length nor would the helical ribbon twist portions be placed as closely together, as illustrated in the drawings. However, for present purposes, the helical ribbon twist portions have been compacted in order to best illustrate schematically the nature of the subject invention. The helical ribbon twist portion 6 is an ordinary helical or auger twist such that the locus of the edge portions thereof define two intermeshing helices which have a common axis :of revolution indicated by the line AA of FIGURE 1.

While FIGURE 1 illustrates a horizontal stacking of helical ribbon twist portions (i.e., a coplanar disposition of the respective axes of revolution for the helical ribbon e.) twist portions 6 and 18), it should be understood that similar grid resistor structures 2 may be vertically stacked as well (i.e., additional helical ribbon twist portions may be provided such that the axes of revolution thereof are parallelly aligned with the axes of revolution of the helical

ribbon twist portions

6 and 18, but are disposed in a plane other than the plane of the axes of the portions 6 and 18).

This vertical stacking arrangement, as well as a further embodiment of the horizontal stacking arrangement, is illustrated by the embodiment of the invention designated by the numeral 32 and illustrated in the FIGURES 6 and 7. The grid resistor structure 32 generally corresponds to the grid resistor structure 2 previously described, except that in essence it amounts to a duplication thereof. The rod 34 is provided with a first tab portion 33 and with front F and rear R faces and with top T and bottom B edges, as indicated in FIGURE 6. The rod 34 is then bent into a first helical ribbon twist portion 50 which extends from the tab portion 34. A bridge member 38a, generally corresponding to the bridge member 8 of FIGURE 1, effects a reversal of direction of the bar 34, which is again twisted into a ribbon twist portion 52 which is parallelly aligned and in intermeshing but non-contiguous relationship with the first portion A second bridge member 386 then effects another reversal of the bar 34, which is then twisted into a third helical ribbon twist portion S t/which is intermeshed with the helical ribbon twist portion 52 in parallel alignment but non-contiguous relationship. A third bridge member 38b then efiects still another reversal of the bar 34, which is similarlytwisted into the fourth helical ribbon twist portion 56 which is again parallelly aligned in intermeshing but non-contiguous relationship with the third helical ribbon twist portion 54. The helical ribbon twist portion 56 then terminates in the tab portion 6d, which corresponds to the tab portion of the FIGURE '1 embodiment.

' Connection points 93 and )7 are provided on the tab portions 33 and 69 respectively, and similarly

connection points

94, 95, and 96 are provided on the bridge members $851,380, and 38b respectively. The FIGURE 6 structure thus represents a one piece continuous resistor unit characterized by four parallelly aligned helical ribbon twist portions, the axes of revolution of which are coplanar. Appropriate electrical connections across the contact points 93-97 can serve to energize the respective helical

ribbon twist portions

50, 52, 54, and 56 in any desired series, parallel, or series-parallel relationship.

FIGURE 7 illustrates a vertical stacking of the grid resistor structure 32 shown in FIGURE 6. A grid resistor structure 32', which is generally similar to the grid resistor structure 32, is juxtaposed thereto such that the coplanar axes of revolution for the four helical ribbon twist portions of the structure 32 are disposed in a plane which is parallel to the plane of the coplanar axes of revolution for the four helical ribbon twist portions of the structure 32. Corresponding connection points are also provided for the bottom grid resistor structure 32, as indicated by the contact points 95, 96, and 97 for the helical ribbon twist portion 54' and 56' of the grid resistor structure 32'.

From the foregoing description, it should be apparent that banks of resistor units may be formed by horizontal, vertical, or horizontal and vertical stacking. Also, each of the individual helical ribbon twist portions may be parts of one continuous resistive element which is suit-ably bent and fashioned into the desired orientation. It is also possible to form a three dimensional matrix of intermeshing helical ribbon twist resistors from a one piece resistive element, as for example by bending the grid resistor structure 32 around the contact point 95 of the bridge member 38c such that the axes of revolution of the helical ribbon twist portions 50 and 52; 54 and 56; 52 and 54; and 50 and 56 are respectively coplanar (i.e., the 56- 52 plane would be parallel with the 54-56 plane, and the 52-54 plane and the 50-56 plane wouldeach be perpendicular to both of the 5tl-52 and the 54-56 planes).

It is also contemplated that the helical ribbon twist portions could be made up in single pieces of any desired length and then stacked on rods or mounted in any other suitable way with appropriate spacers and insulations to form resistor units of the type described herein. Various conventional means could be utilized to weld or clamp together the respective ends of such individual helical ribbon twist portions in order to form a current resistive path defined by a horizontally, vertically, or horizontally and vertically aligned helical ribbon twist stacked arrangement, as heretofore described. Furthermore, the stacked resistor structures described herein could be mounted relative to a fixed support in vertical, horizontal, or other dispositions, as required.

It should be understood that various changes, modifications, and alterations may be effected in the details of construction, operation and materials for the various elements, without departing from the spirit and the scope of the instant invention, as defined in the appended claims.

What is claimed is:

ll. A stacked resistor structure comprising:

a plurality of ribbon resistive elements of smooth helical twist, each having a common axis of revolution and center,

said resistive elements arranged in intermeshing but non-contiguous relationship with the common axes and centers of the plurality of elements parallel; and

means for connecting said resistive elements to a source or" electric potential whereby the elements may be interconnected in series, parallel, or series-parallel relationship.

2. A resistor structure as claimed in claim I in which the respective axes of revolution of said resistive elements are coplanar.

3. A one-piece resistor structure comprising:

a plurality of ribbon portions of smooth helical twist, each having a common axis of revolution and center, arranged in intermeshing but non-contiguous relationship with the common axes and centers parallelly aligned, connected by bridge portions and initiating and terminating in tab portions;

each of said port-ions being formed of resistive material; and

means on said tab portions for connecting the structure to a source of electric potential.

4. A resistor structure as claimed in claim 3 and further comprising means on said bridge portions for connecting he structure to a source of electric potential, whereby the said helical ribbon twist portions may be interconnected in series or parallel relationships.

5. A resistor structure as claimed in'claim 4 in which the respective axes of revolution are coplanar.

6. A three-dimensional resistor structure comprising:

a first one-piece resistor structure comprising:

a plurality of ribbon portions of smooth helical twist, each having a common axis of revolution and center, arranged in intermeshing but non-contiguous relationship with the common axes and centers parallelly aligned, connected by bridge portions and initiating and terminating in tab portions; second one-piece resistor structure comprising: plurality of ribbon portions of smooth helical twist, each having a common axis of revolution and center arranged in intermeshing but non-contiguous rela tionship, with the common axes and centers parallelly aligned, connected by bridge portions and initiating and terminating in tab portions; each of said portions being formed of resistive material; said first one-piece resistor structure and said second one-piece resistor structure being juxtaposed in intermeshing but non-contiguous relationship; and

A three-dimensional resistor structure comprising: first one-piece resistor structure comprising:

a plurality of ribbon portions of smooth helical twist,

each having a common axis of revolution and center arranged, in intermeshing but non-contiguous relationship With the common axes and centers parallelly aligned, connected by bridge portions and initiating and terminating in tab portions;

a second one-piece resistor structure comprising: a plurality of ribbon portions of smooth helical twist,

each having a common axis of revolution and center, arranged in intermeshing but non-contiguous relationship With the common axes and centers parallelly aligned, connected by bridge portions and initiating and terminating in tab portions;

each of said portions of both grid resistors being the axes of revolution and of the plurality of ribbon formed of resistive material;

portions or" the first resistor structure being coplanar and the axis of revolution and center of the plurality of ribbon portions of the second grid resistor structure and being parallelly aligned in intermeshing but non-contiguous relationship with the ribbon portions of the first resistor structure; and

means on said tab portions for connecting the resistor structure to a source of electric potential.

8. A resistor structure as claimed in claim 7 and further comprising means on at least one of the bridge portions for connecting the resistor structure to a source of electric potential, whereby the plurality of ribbon portions may be interconnected in series or parallel relationships.

9. A resistor structure as claimed in claim 6 and further comprising means on the bridge portions for connecting the resistor structure to a source of electric potential, whereby the plurality of ribbon portions may be interconnected in series or parallel relationships.

References Cited by the Examiner UNITED STATES PATENTS RICHARD M. WOOD, Primary Examiner.

Claims

1. A STACKED RESISTOR STRUCTURE COMPRISING: A PLURALITY OF RIBBON RESISTIVE ELEMENTS OF SMOOTH HELICAL TWIST, EACH HAVING A COMMON AXIS OF REVOLUTION AND CENTER, SAID RESISTIVE ELEMENTS ARRANGED IN INTERMESHING BUT NON-CONTIGUOUS RELATIONSHIP WITH THE COMMON AXES AND CENTERS OF THE PLURALITY OF ELEMENTS PARALLEL; AND MEANS FOR CONNECTING SAID RESISTIVE ELEMENTS TO A SOURCE OF ELECTRIC POTENTIAL WHEREBY THE ELEMENTS MAY BE INTERCONNECTED IN SERIES, PARALLEL, OR SERIES-PARALLEL RELATIONSHIP.