Heating element assembly

Abstract

An assembly for supporting an open coil heating element is provided. The assembly includes at least one cross-member having at least two cutouts, formed in a single row, extending from the top edge and a capping member for each cross-member. The heating coil is secured in position by a plurality of insulating bushings, each of which is captured in part by the surfaces of the cross-member defining the cutout and in part by the capping member. The capping members are secured to the cross-members by means of a ridge and bent-over tabs to rigidly secure the bushings between the cross-member and the capping member.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application relates to the same field, heating element assemblies, as co-pending application Ser. No. 391,265, filed Aug. 24, 1973, now U.S. Pat. No. 3,812,322 for "HEATING ELEMENT ASSEMBLY" by Charles Osterkorn, Leo Buck, William Kloos, and Salvatore Marino, assigned to the same assignee as the present invention.

BACKGROUND OF THE INVENTION

The present invention relates generally to heating coils and in particular to an improved construction for supporting an open coil heating element.

Open coil heating elements are widely used and find many applications in the heating and air conditioning fields. For example, such coils may be used as heaters in conjunction with air conditioning units to provide all-weather temperature control.

The heating coil comprises a high resistance wire, such as Nichrome, which when a current passes through it, rapidly elevates in temperature and dissipates heat. The amount of heat generated is proportional to the resistance of the Nichrome wire and it is common practice to coil the wire and then loop the coil back and forth to reduce the overall space requirements necessary to contain a wire of the length required for a particular application. Oftentimes, more than one coil is utilized.

Heretofore, various schemes have been suggested and utilized for the purpose of supporting the heating coil. Typical of the prior art is U.S. Pat. No. 3,641,312 which discloses a frame including a plurality of cross-members which support insulator bushings through which the heating coil passes. Each of the bushings passes through a hole in the cross-member and is held in position by a plurality of radial tongues arranged about the periphery of the hole. The bushings must individually be positioned and locked in position to insure safe and proper operation. It is not until all the bushings are in position that the Nichrome wire can be passed through the bushings and the heating assembly completed. While this arrangement produced satisfactory results, it is relatively time-consuming to assemble and hence expensive from a manufacturing standpoint.

A heating assembly element is also described and claimed in the previously-referenced co-pending application. While the structure and locking mechanism described and claimed in that application are entirely adequate, we have now discovered a modified structure which provides both for easier assembly and manufacture and for more positive locking of the bushings into the assembly.

SUMMARY OF THE INVENTION

In accordance with the present invention, a cross-member, formed from sheet metal, has at least one portion in a generally strip-like configuration. Within this strip-like portion, at least two cutouts are formed to accommodate the insulating bushings through which the heating wire will be threaded. The bottom and sides of the cross-member may be bent over to allow them to be secured into an overall assembly, for example, by attachment to an elongated arm, or for strengthening the cross-member.

Two tabs are formed, one on each side, of the strip-like portion, adjacent the top of the cutout in the strip-like portion, for securing the capping member of the present invention.

The capping member employed in accordance with the present invention is also formed from a piece of sheet metal, but is not provided with cutouts. It is rolled along a line which is closer to one edge of the sheet than to the other so as to form a U with legs of unequal length, the base of the U providing a stop when the capping member is placed over the cross-member. A ridge is bent on the longer leg of the U formed by rolling of the capping member sheet metal. One of the tabs formed on the strip-like portion of the cross-member can be bent into a U-shaped configuration, leaving sufficient space between the strip-like portion and the bent-over tab to accommodate one of the legs of the capping member.

In order to assemble the entire heating element assembly, an insulating bushing is placed in each of the cutouts formed in the cross-member. The capping member is then placed onto the top of the strip-like portion of the cross-member. The capping member is brought down all the way until the base of the U rests upon the portions of the strip-like portions which remain after formation of the cutouts. Either or both tabs, depending upon whether one has previously been bent over, are then bent into a U-shaped configuration, resting above the ridge on the capping member, so as to firmly secure the capping member to the cross-member and thus capture the insulating bushings between the two.

Because there are no depending members between cutouts on the capping member, assembly is easily accomplished. Further, as the ridge on the capping member fits below the bent-over tabs, the capping member is firmly secured to the cross-member and is held in position.

BRIEF DESCRIPTION OF THE DRAWING

In the accompanying drawings:

FIG. 1 is an exploded view of the assembly of the present invention including a cross-member, capping member, and several insulating bushings;

FIG. 2 is a perspective view showing the capping member in place on the cross-member, prior to bending of the securing tab; and,

FIG. 3 is a perspective view of one end of the assembly in fully assembled position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the accompanying drawings, the heating element assembly of the present invention includes a cross-member 1, a capping member 20, and a plurality of insulating bushings 30. The form of the insulating bushings is well known in the art and, accordingly, will not be described in further detail here.

The cross-member 1 includes the strip-like portion 2 within which are formed a plurality of cutouts 3 defined by adjacent walls 4 formed by the portions 5 of the strip-like portion remaining after formation of U-shaped cutouts 3. The sides 6 of the strip-like portion may be bent over to provide means for securing the assembly into a larger structure, as by means of fastener openings 8. Bottom 7 is added in order to strengthen the overall structure, particularly by providing additional rigidity. Tabs 9 and 10 are formed at either edge of the strip-like portion 2, adjacent the top of the strip-like portion, generally in alignment with the tops of cutout 3.

Capping member 20 includes two legs 21 and 22 formed by rolling a piece of sheet metal along base line 23. Longer leg 22 is bent at line 24 to form a ridge 25, generally at right angles to the leg 22.

To assemble the device, one of the tabs, for example, tab 9, is bent into a U with respect to the strip-like portion 2, leaving sufficient space between the legs of the U to accommodate leg 22 of capping member 20. Leg 22 is then placed in the space between tab 9 and strip-like portion 2, making certain that ridge 25 lies below tab 9. The capping member is then moved downwardly until base line 23 rests upon upstanding portions 5 of strip-like portion 2. In this position, ridge 25 will lie below tab 10. Tab 10 is then bent into a U configuration with respect to strip-like portion 2, as illustrated in FIG. 3. In this way, capping member 20 is firmly secured to cross-member 1. The capping member is prevented from movement along the cross-member by abutment, on either side, with the bend line of the U formed by bending over of tabs 9 and 10 and is prevented from movement away from the cross-member by abutment of tabs 9 and 10 on ridge 25.

A more preferable way of forming the heating element assembly of the present invention is to leave both tabs 9 and 10 in their originally formed condition prior to application of capping member 20. Capping member 20 is placed upon upstanding portions 5 of strip-like portion 2 until base line 23 rests upon these upstanding portions. Capping member 20 is then aligned with respect to the strip-like portion, and tabs 9 and 10 are bent over, above ridge 25 so as to secure capping member 20 to the strip-like member 2. The same benefits are generally obtained with either method of assembly, but the method just described is generally more easily accomplished with manufacturing equipment on a mass production basis.

Because it is unnecessary to align cutouts in the caping member with cutouts in the cross-member, assembly is far easier than with prior devices. Further, a more positive lock is provided. Additionally, with that assembly method where a tab is bent over prior to application of the capping member, the capping member is positively positioned against that tab at the beginning of assembly.

Claims

We claim:

1. An assembly for supporting an open coil heating element, said assembly comprising:

a. at least one cross-member having a generally strip-like configuration and having at least two cutouts therein, in a single row, extending from the top edge;

b. tab members formed at the sides of said cross-member, generally adjacent the top edge of said member;

c. a capping member, formed in a generally U-shaped configuration to form a channel, and a ridge formed on one leg of said U;

d. an insulator bushing seated in and partially captured by each of said cross-member cutouts and partially captured by said capping member, each bushing having an opening therein for said heating coil to pass through; said tab members holding against said capping member above said ridge, whereby said tab members secure said capping member to said cross-member.

2. The heating element assembly of claim 1 wherein means are provided on said cross-member for assembly into larger structures.

3. A method for forming an assembly to support an open coil heating element comprising:

a. forming a cross-member, at least a portion of which is in a generally strip-like configuration having at least two cutouts therein, in a single row, extending from the top edge, and having tabs on each side, generally adjacent to the top edge;

b. forming a capping member in a U-shaped configuration, one leg of said U being provided with a ridge;

c. placing an insulator bushing within each of said cross-member cutouts;

d. placing said capping member on said generally strip-like portion;

e. moving said capping member down over said cross-member so that the base of the U of said capping member rests upon the upstanding portion adjacent the cutouts in said cross-member; and

f. securing said capping member to said cross-member by said tabs, by bending said tabs above said ridge.

4. The method of claim 3 wherein said capping member is held in place by bending both of said tabs about said capping member after said capping member is in place.

5. The method of claim 3 wherein, in addition, the assembly is formed by bending one of said tabs into a generally U-like configuration prior to application of said capping member, by inserting said capping member between the legs of the U formed by bending of said tab, the ridge of said capping member being below said tab, and by bending the second tab about said capping member after said capping member is in place.