US2795682A - Electric heaters - Google Patents

Description

' Filed June 22. 1954 June 11, 1957 D. KNOLL 2,795,682

' ELECTRIC HEATERS 3 Sheets-Sheet l INVENTOR ,Dflv/Q Awo ATTORNEY June 11, 1957 o. KNOLL 2,795,682

mzcmxc HEATERS Filed June 22. 1954 5 Sheets-Sheet 2 INVENITQR Dar/o AA/ou BY MM ATTORNEY June 11, 1957 Filed June 22, 1954 D. KNOLL ELECTRIC HEATERS 3 Sheets-Sheet 3 United States Patent 2,795,682 ELECTRIC HEATERS David Knoll, New York, N. Y., assignor to Berko Electric Mfg. Corp., Queens Village, N. Y., a corporation of New York Application June 22, 1954, Serial No. 438,444 13 Claims. (Cl. 219--34) This invention relates to electric heaters and more specifically to electric radiant panel heaters for heating rooms, offices, stores or the like.

The design and construction of radiant panel heaters :and particularly those embodying, for instance, a sheet of conductive glass, presents a number of difiicult problems because of the fragility of the panel and the close proximity of the wiring to the panel itself. These factors, among others, have resulted in a material increase in cost of panel heaters which nevertheless have not been entirely satisfactory. Accordingly, one object of the invention is the provision of an improved radiant panel heater that embodies a simplified, effective and inexpensive support for the heating panel which prevents subjection of the panel to undue stresses and strains while, at the same time, enabling the attainment of highly satisfactory electrical connections thereto.

In practice the present invention is embodied in a rectangular structure adapted to be secured against the wall and connected to electric wiring. The structure is slightly larger than the panel of conductively coated glass and relatively thin so that it does not extend out into the room.

Another object of the invention is the provision of an improved highly compact panel heater arranged and constructed to greatly facilitate assembly and which may be quickly and easily installed in any desired position in the room to be heated. Moreover, by reason of its unique construction, the panel and associated electrical components can be easily removed for adjustment and replacement or repair when necessary.

A further object of the invention is a new and improved structure for supporting heating panels of glass and other materials which are readily adaptable to a wide variety of panel sizes and shapes. Through the employment of fundamental design characteristics, the manufacturing problem of providing supporting means for different sized panels is reduced to a minimum and the assembly of different sized heaters may be accomplished with little, if any, disruption of the assembly process.

Another object of the invention is an improved heater having dual protective means for the glass panel in the form of a subassembly including reflector means for securing and holding the glass panel and effecting electrical connections therewith and an outer housing for holding the subassembly and protecting it against direct mechanical shock. This arrangement of elements not only provides an inexpensive, dependable and compact support for the heater itself, but at the same time greatly facilitates installation.

Still another object of the invention is an improved radiant panel heater that provides heat through direct radiation and by convection. By means of this improved structure, the provision for air flow through the heater functions to provide mere effective general heating as well as to protect the electrical elements such as the wiring and the like from the high internal heater temperatures which would otherwise obtain.

The above and other objects and advantages will become more apparent from the following description and accompanying drawings forming part of this application.

The accompanying drawings show, for purposes of illustrating the present invention, one embodiment in which the invention may take form, it being understood that the drawings are illustrative of the invention rather than limiting the same.

In the drawings:

Figure 1 is a perspective view of the heater in an upright position as in normal use;

Figure 2 is an exploded view of the embodiment of the heater illustrated in Figure l to show the major elements in a horizontal position;

Figure 3 is an exploded view of a fragmentary portion of the heating unit shown in Figure 2;

Figure 3A is a perspective view of the conductive heating panel;

Figure 4 is a cross sectional view of the assembled heater and taken on the line 4-4 of Figures 6, 7 and 8.

Figure 5 is a cross sectional view of Figure 4 along the line 5-5 thereof and at a larger scale; and

Figures 6, 7 and 8 are cross sectional views of Figure 4 along the lines 6-6, 7-7 and 88, respectively.

Referring to Figures 1 and 2 showing perspective and exploded views respectively of the improved heater in accordance with the invention, it will be observed that it includes four basic elements; namely the outer casing or shell 10 which forms the back, top and side walls of the device, the glass-panel carrying subassembly 11, an elongated bottom oover or closure 12 and a grill or screen 13 which overlies the face of the heater panel 14 in the subassembly. It is held in position by engagement with the four openings 15 in the front face of the shell 10.

The assembled heater is normally installed by fastening it to a vertical wall by screws, or other suitable means, engaging openings 16 in the back wall 17 of the shell 10. In the installation of the heater, the cover plate 12 and subassembly 11 are first removed from the shell which is then secured in position against a wall or the like with a suitable electric cable being brought in through the opening 18 in the lower edge of the back 17. The heating panel subassembly 11 is then positioned in the shell by inserting the upper pair of tabs 19 into slots 20 in the top wall of shell 10 and securing the lower pair of tabs 19 by sheet-metal screws '19 or the like to cooperating bracket members 21 secured to the shell.

Since the heater is normally installed in a vertical position, and, in order to support the subassembly while it is being secured in position by the screws 19', it is provided with extending tabs 22, two of which overlie the brackets 21. The other two tabs 22 are used should the assemblage be inverted.

These tabs 22 also function to support part of the weight of the assembly 11 even when the attaching screws are in place. The utilization of the tabs 19 and 22 are the sole means for mounting the subassembly 11 within the shell 10 enabling the fabrication of both the members 23 in an identical manner and results in materially lower manufacturing and assembly costs.

When the heater assembly 11 is installed within the shell 10, theentrance cable installed in the opening 18 is either connected to the heater wires 24 directly or through a suitable thermostat or switch represented by the knob 25 on the bottom cover or closure member 12. Upon completion of the connections, the cover member is positioned in place and held by a pair of screws 26 or other suitable fastening means.

In order to provide for the flow of air through the heater and prevent over heating of the electric wires and casing 10, and provide heat by convection, suitable louvres 27 are provided in the cover 12 for the admission of air. A part of this air passes upwardly between a reflector member 28 and the back 17 of shell 10 for cooling purposes and the remainder passes through a series of slotted openings 29 in the lower flanged edge 30 of the reflector 28 and into a space bet-ween the reflector 28 and the heating panel 14. The air to be heated by passage between the panel 14 and reflector 2-8 is exhausted through an elongated space between the upper edge of the panel 14 and the flanged edge 31 of reflector 28, while the cooling air entering the space between the reflector 28 and the back 17 of the shell 10 passes outwardlythrougha space between the flanged edge 31 and the upper edge 32 of the shell 1!). Thus, with this improved design, provision is made for direct radian-t heating, indirect heating through convection by the passage of air in back of the heating panel 14 and cooling of the shell 10 and electric wiring.

Referring now to Figures 38 inclusive, the heater panel 14 preferably comprises a glass sheet having a highresistance conductive coating 33 on the rear surface thereof (Fig. 3A), and low resistance conductive strips 34 the opposing edges for the purpose of uniformly distributing current through the coating 33. It is supported by the reflector 28 in cooperation with the end channels 23, as previously described. By reason of the cooling effect of the air flow through the heater coupled with the reflective surface, the reflector 28 may be formed of relatively thin aluminum. In order to provide the desired rigidity, however, each end thereof is provided with a rearwardly turned edge 35 and the flanged parts 30 and 31 are provided with folded edges 30' and 31.

The reflector 28 supports a pair of electrical contacting assemblies 36, each having an insulating strip 37 of laminated glass fiber or the like and an overlying strip 38 of brass or other conductive material. Two sets of spring contacting means 39, each having a pair of triangu'l arly shaped portions 40, are riveted to the brass strip 38 by rivets 42 which also secure the strip 38 to the insulating strip 37. The apex of each spring member 30 carries a contacting button 41 of carbon or the like and the four buttons on each contact strip bear against their cooperating conductive strips 34 on the panel 14 to effect electrical contact. The entire contact assembly 36 is secured in place on the reflect-r 28 by rivets 43 engaging corresponding openings 44 in the insulating strip 37 and 45 in the reflector 28. When the heater panel 14 is posi t-ioned over the reflector with the two sets of buttons 41 in contact with the conductive strips 34, the spring mem bers 40 hold the heater above its normal position. However, when the side brackets 23 are fastened in place the panel is pressed downwardly toward the reflector and causes the outer or free ends of the spring members 40 to move outwardly in frictional contact with the strip 38. Thus substantially uniform pressure is applied between each but-ton 41 and the conductive strips 34 to insure positive electrical contact.

The lead wire 24 for each strip 36 is connected to the conductive strip 33 and passes through aligned openings in one end of the insulating strip 37 and reflector 28. In order to prevent the rivets 42 from contacting the reflector, the latter is provided with suitable indented portions 46 as shown in Figures 3, 4 and 5.

in securing the panel 14 in position on the reflector 28, it is of course important to effect both electrical as Well as thermal insulation. This is accomplished by means of four corner members 47 of ceramic or other suitable material, each having a rectangular recess 48 slightly wider than the thickness of the panel 14. This recess is lined with a resilient, or slightly compressible, material 49, such as asbestos sheet. The members 47 thus receive and firmly hold the panel as shown in Figures 4 to 8. The outer edge 50 of each corner member is slightly rounded to fit snugly into the corners of the reflector 28 as may be observed in Figure 4, and has a bevel 511 to cooperate with the lip 52 on the bracket 23 Fig. 7), and a depression 53 to receive the inner end of an assembly screw 57 (Fig. 4).

The side brackets 23 are both identical and may be formed of a single sheet of material by conventional punch press and metal forming apparatus. Each bracket essentially comprises a side wall 54 having an upturned lip 55 and a front wall 56 having an inwardly formed flanged part or lip 52. The ends are each bent to form the angle or tab 22 as previously described, as well as a tab 19 for securing the heater assembly 1 1 to the shell 10.

:In the assembly of the panelsupporting elements, the panel 14 is first placed on' the reflector 28 with the conductive strips34 in contact with the buttons 41. The corner members 47 are then placed on each corner of the panel and the side members 23 are installed. In so doing the lip 55 of each bracket 23 engages the edge 35 of the reflector. The brackets are then moved inwardly one toward the other while the panel 14 is pressed downwardly so that the lip 52 of each bracket moves over the associated corner members and into a slightly overhanging position, as may be seen in Figures 7 and 8. In this position the lip 52 of each bracket 23 contacts the edges of the associated corner members and forces them snugly against the Wall 54 of the bracket to lock them in position. At the same time, firm electrical contact is effected with the heater. The brackets 23 are then secured in position by screws 57 which extend through openings 58 in brackets 23 and thread-ably engaging openings 59 in reflector flanges 30 and 31.

With the foregoing structure, the side brackets 23 may be identical in sturcture and used with any length panel. The corner members 47 and the electrical contact assemblies 36 may be employed With any size panel that may be supported at its corners, and the reflectors while suitable only for a given size of panel 14, are otherwise identical in all details. The design and construction of the component parts of this improved heater in this manner enables the manufacture of heaters in a wide range of sizes and shapes without necessitating specially prepared elements for each different size. This factor, coupled with the simplicity and uniformity of the elements and the facility with which different sized heaters may be fabricated without difliculty on a single assembly line, effects a material decrease in cost of the finished heater.

Since it is obvious that the invention may be embodied in other forms and constructions Within the scopeof the claims, I wish it to be understood that the particular form shown is but one of these forms, and various modifications and changes being possible, I do not otherwise limit myself in any way with respect thereto.

What is claimed is:

1. In an electric heater having a shell, a rectangular heating panel within said shell, including electric terminal means along opposing edges thereof, a back-plate for said panel having narrow flanges extending rearwardly from one pair of opposing edges and relatively wide flanges extending forwardly from the other pair of opposing edges, a pair of spring mounted electrical contact means on the front side of said plate and positioned along said one pair of opposing edges, insulating means engaging each corner of said panel to hold the latter in spaced relationship to the front of said plate and with said terminal means in alignment with and overlying said contact means, and a pair of channel-like side brackets engaging said rearwardly extending flanges and overlying the edges of said panel, said brackets engaging said insulating means to hold the panel and plate in position, one relative to the other with the terminals and contacts in firm engagement and mounting means on each end of said brackets.

2. In an electric heater according to claim 1, wherein each of said mounting means includes a pair of rigid tabs one of which extends in a plane parallel to said plate and includes an opening therein and the other extends in a direction perpendicular to said plate.

3. An electric heater comprising an outer shell having a back, a top and two side walls extending forwardly of said back member, a rectangular heating panel within said shell, including electric terminal means along opposing edges thereof, a back-plate for said panel having narrow flanges rearwardly extending from one pair of opposing edges, a pair of spring mounted electrical contact means on the front side of said plate and positioned along said one pair of opposing edges, insulating means each having a recess therein in engagement with a corner of said panel. for holding the panel in spaced relationship to the front of said plate and with said terminal means in alignment with and overlying said contact means, and a pair of channel-like side brackets engaging said rearwardly extending flanges and overlying the edges of said panel, said brackets engaging said insulating means and holding the panel and plate in position, one relative to the other with the terminals and contacts in firm engagement, mounting means on each end of said brackets and cooperating means on said shell for holding said panel in position on said shell.

4. An electric heater according to claim 3, wherein said mounting means comprises at least one tab extending outwardly from each end of said brackets and said cooperating means includes a pair of slots in the top wall of said shell for receiving a pair of tabs and a pair of spacing bracket members on the back of said shell for engaging and holding the other pair of tabs, said cooperating means functioning to hold the panel and backplate in spaced relation to the back of said shell.

5. In an electric heater, a normally vertical, conductively coated glass panel adapted to be heated by the passage of an electric current through the coating, and panel supporting means comprising a vertical reflector with upper and lower, forwardly extending flanges, insulating corner members having l...-shaped cutouts which receive the corners of the glass panel and have back walls and side walls bearing against the front face of the reflector and the flanges and disposed at the corners of the reflector, channel-shaped brackets secured to the reflector across the open ends thereof and having walls which engage the side and front walls of the corner members to hold the corner members against the panel and front walls which overlie the edges of the panel to protect it.

6. The heater of claim 5, wherein the rear face of the glass panel has conducting strips along its opposite ends and wherein the reflector insulatedly supports a conducting strap behind each :conducting strip on the panel and the conducting straps carry arched resilient conducting strips provided with carbon buttons which bear against the conducting strips on the panel.

7. An electric heater comprising a conductively coated, rectangular glass panel provided on the rear face with conducting strips extending along the entire length of two opposite edges thereof, a metallic supporting plate spaced rearwardly of the panel, means for securing the supporting plate and panel in such spaced relationship, and two plate-carried current connecting means for furnishing connection to the conducting strips at a plurality of points therealong, each comprising a long, relatively stiif metal strap, means including an insulating strip for securing the conductive strap to the front face of thesupporting plate opposite one of the conducting strips on the glass plate, a plurality of double bowed resilient metal strips spaced along the conducting strap and having free end portions slidably bearing on the front face of the conducting strap and a central portion secured to the front face of said strap, and a carbon button carried at the crest of each arched portion and bearing against the conducting strip on the glass plate.

8. In an electric heater, a back plate, a conductive glass heater panel, connecting strips extending along opposing edges of said panel for the application of electrical energy thereto, at least two groups of spring biased contacts, said groups being carried by and extending along opposing edges of said back plate for cooperation with said connecting strips, corner insulating members in engagement with said panel and resting against said back plate, a pair of side channel members substantially coextensive with said opposing edges of the plate and panel, said channel members holding said panel, plate and corner members in position one relative to the other with said spring biased contact strips in engagement with said connecting strips, and means for applying electric energy to said contact groups for heating the panel.

9. In an electric heater according to claim 8, a shell and means on said channel members for holding the back plate and heater panel assembly in said shell.

10. In an electric heater according to claim 8 wherein at least part of each channel portion overlying said panel is bent inwardly toward said panel to limit outward deflection of the panel between the corner members.

11. In an electric heater having a conductively coated glass panel and contact strips extending along a pair of opposing edges of said panel and forming part thereof, means for electrically contacting said strips each comprising an elongated strip of conductive material, at least one double bowed contact member carried on one side of said elongated strip, said bowed member being formed of a strip of resilient metal with the center secured to said elongated strip and the outer ends of the bows slidable relative to said elongated strip when the centers of the bows are depressed, at least one carbon button contact carried at the center of each bow and a strip of insulating material secured to the other side of said elongated strip for supporting and insulating said elongated strip.

12. A substantiall vertical electric heater comprising a shallow shell, a heater assembly within said shell, a pair of rigid tabs at each end of the upper and lower edges of said assembly, One tab of each pair extending in a plane parallel to said heater assembly and the other tab of each pair extending in a plane perpendicular to said assembly, and means on said shell cooperating with said one tab of each pair for holding said assembly in said shell, the last said means further including raised abutments at the lower part of said shell for engaging two of said other tabs on the lower edge of said assembly to support and aid alignment of said assembly during installation in said shell.

13. In an electric heater, a back plate, a conductive glass heater panel, connecting strips extending along opposing edges of said panel for the application of electrical energy thereto, at least two groups of spring biased contacts, said groups being carried by and extending along opposing edges of said back plate for cooperation with said connecting strips, corner insulating members in engagement with said panel and resting against said back plate, a pair of side channel members at least coextensive with said opposing edges of the panel, said channel members holding said panel, plate and corner members in position one relative to the other with said spring biased contact strips in engagement with said connecting strips, and means for applying electric energy to said contact groups for heating the panel.

References Cited in the file of this patent UNITED STATES PATENTS 747,821 Wilson Dec. 22, 1903 1,881,461 Furtney Oct. 11, 1932 2,353,061 Oldenboom July 4, 1944 2,455,967 Adams Dec. 14, 1948 2,458,184 Marick Jan. 4, 1949 2,495,788 Trist Jan. 31, 1950 2,536,648 Lamb Ian. 2, 1951 2,623,150 Boecher Dec. 23, 1952 2,650,286 Ramos Aug. 25, 1953 2,662,963 Wessel Dec. 15, 1953 2,668,220 Spurr Feb. 2, 1954 2,677,748 Naylor May 4, 1954 2,679,569 Hall May 25, 1954 2,706,763 Glynn Apr. 19, 1955 2,715,174 Nathanson Aug. 9, 1955

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