US3189727A - Electric space heater - Google Patents

Description

June 15, 1965 1. JEPSON ETAL 3,139,727

ELECTRIC SPACE HEATER Filed June 27, 1961 3 Sheets-Sheet 1 jig 29 Z June 15, 1965 JEPSON ETAL 3,189,727

ELECTRIC SPACE HEATER Filed June 27, 1961 5 Sheets-Sheet 5 United States Patent 3,189,727 ELECTRIC SPACE HEATER Ivar Jepson, Oak Park, James R. Cochrane, Chicago, and Robert D. Grahn, Hinsdale, Ill., assignors to Sunbeam Corporation, Chicago, Ill., a corporation of Illinois Filed June 27, 1961, Ser. No. 119,918 12 Claims. (Cl. 219-377) This invention relates to electric space heaters having means for causing circulation of heated air. The invention has more particular reference to portable room heaters but is applicable in certain of its phases to radiant and convection heaters designed for other purposes.

Portable room heaters of the type with which this invention is primarily concerned are of relatively small bulk so as to be easily moved about and so as to be capable of being stored when not in use in a relatively small space such as a closet or the like. By virtue of this small size, it is apparent that the electrical heating element and electrical control element must be placed within the small space provided by the housing of the heater. The association of electrical elements with a portable electric heater of relatively small bulk presents some problem by virtue of the fact that the electrical elements and components must be mounted closely adjacent .to the housing and to the heat reflecting portion of the portable heater; and yet must have sufficient clearance therewith to provide safety to a user from electrical shock and from overheating of the components. Moreover, such portable heaters must be manufactured economically so as to make them available on the market at a low cost.

As such heaters are frequently used in living quarters of a house and similar places, it is desirable that the portable heater be quiet in operation and neat in appearance. It would be particularly desirable for the portable heater to be so constructed as to serve as an additional piece of furniture, for example, as a small table or rack.

It is therefore an object of the present invention to provide an improved portable electric heater which possesses the aforementioned advantages.

A further object of the present invention is to provide an improved portable electric heater which is small in size and yet which provides proper clearance between the electrical components and the other parts of the heater.

A further object of the present invention is to provide a portable electric heater which is economically manufactured and assembled.

A further object of the present invention is to provide an improved portable electric heater which is very quiet in operation.

Yet another object of the present invention is to provide an improved portable electric heater having a pleasing appearance and which may be used as an additional piece of furniture.

Yet another object of the present invention is to provide an improved portable electric heater which is very small and compact in size.

Further objects and advantages of the present invention will become apparent as the following description proceeds and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of the present invention reference may be had to the accompanying drawings, in which:

FIG. 1 is a perspective .view of an improved portable electric heater embodying the present invention;

FIG. 2 is an enlarged sectional view of the portable electric heater otf FIG. 1, taken along line 2 2 thereof;

FIG. 3 is a fragmentary sectional view taken on line 3,139,727 Patented June 15, 1965 33 of FIG. 2, assuming that FIG. 2 shows the complete structure;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 2, assuming that FIG. 2 shows the complete structure and with the tip switch shown in closed position;

FIG. 5 is an enlarged fragmentary view looking in the direction of the arrows 5-5 of FIG. 4, assuming that FIG. 4 shows the complete structure;

FIG. 6 is a fragmentary sectional view taken along line 6-6 of FIG. 5;

FIG. 7 is an exploded perspective VlNV with certain portions cut away of the heating element subassembly of the portable electric heater of the present invention; and

PEG. 8 is a schematic diagram disclosing the electric circuit embodied in the room heater of the present invention but with the tip switch shown in open position.

Briefly stated, the present invention is concerned With a portable electric heater having a reflector assembly positioned within a housing and provided with air passage means to provide for both radiant and convection heating from the heater. In order to provide for a heater of small compact size, the reflector includes a pair of spaced end walls, each closely juxtaposed to a respective one of the end walls forming the housing. The reflector end walls are provided with elongated aligned openings for spring mounted insulating supports around the heating element is wound.

According to another feature of the present invention, the control or heat selector dial of the heater as well as the handle thereof is recessed into a wall of the housing thereby providing a substantially fiat surface adapting the heater for use as an end table or the like.

Referring now to the drawings, there is illustrated a portable electric space heater, generally shown at 10, and including a casing or housing 11, supporting a reflector assembly 1-2 therein. The casing 11 is illustrated as a rectangular housing provided with rear wall 1 1a, front wall 11]), top wall 110, end walls 11d and He and bottom wall 111. A heating element assembly 13 is positioned in front of the reflector assembly 12, so that the reflector assembly 12 is effective to transmit radiant heat from the heating element assembly 13. Moreover, the heater 10 includes a motor and fan assembly 14 within the housing 11 thereof and positioned to draw air through a plurality of louvers 15 in the rear wall 11a of the housing ll, and to direct the air through a plurality of slots 16 in the reflector assembly 12, the air then passing through a grille 17 extending across an opening 18 in the front wall 11b of the housing 11. In this manner the heater it) is effective to transmit heat by convection as well as by radiation. The grille 17 is preferably formed of expanded metal or the like.

In order to provide for the selective control of a de sired heat, the heater 10 is provided with a temperature control assembly 19 (FIGS. 2 and 4), including a thermal responsive control switch 20 (FIGS. 4 and 8) positioned within the housing 11 and connected to control the operation of the motor and fan assembly 14. As illus trated, thermal responsive control switch 20 includes a bimetallic element 21, a pair of relatively movable contacts 22a and 22b mounted on flexible supports such as leaf springs or the like and a rotatable control knob 23 whose function will become apparent from the ensuing description. The bimetallic element 21 and leaf springs are preferably supported in an insulated stack secured Within casing 11 as from the top thereof. Furthermore, bimetallic element 21 is adapted to deflect upon heating so that the right-hand end, as viewed in FIG. 8, moves upwardly and an insulating extension 21a thereon engages and moves the leaf spring supporting movable contact 22a with the resultant opening of the circuit at contacts 22a and 22b. The contact 22b might be conor other surface. heater portion of the heating element assembly 13, de-

J] sidered the stationary contact and it is selectively removable in response to rotation of control knob 23 which has an insulating extension 23a extending through an opening in the leaf spring supporting contact 2211, thereby to change the positioning of the stationary contact 2222 and, hence, to determine the temperature at which bimetallic element 21 opens the switch comprising contacts 22a and 22b. Suitable indicia may be associated with control knob 23 to indicate the setting thereof, which indicia might comprise Off, Low, Medium, High, etc. Thus, the temperature control knob 23 is in effect a heat selector dial which extends outside of the top life of housing 11 thereby permitting manual control of the temperature setting of the thermal responsive control switch 20. The temperature control assembly 19, due to its position immediately in front of fan 14 and louvers 15, would normally be principally responsive to the temperature of the room air passing across the bimetallic element 21 and would be relatively unaffected by heat radiated from the reflector assembly 12. For a portable heater of this type to meet present day safety standards, it is necessary that the thermostat respond suficiently to the temperature of the reflector assembly 12 so that the heater circuit'will be opened it the front of the heater It is placed so closely to a wall or other obstruction that there is danger of setting such wall or other obstruction on fire. To achieve this condition where the temperature control assembly is positioned in the flow of the room temperature air and still have it respond to the temperaiture of the reflector assembly, a baffle 24 is provided to prevent the direct flow of room temperature air across the bimetallic element 21. As is best illustrated in FIGS.

2 and 4, the baffle 24 encloses the thermal responsive control switch 20 on all sides except the front and the side away from the motor and fan assembly 14. With this arrangement, the bimetallic element 21 is exposed to radiation from the reflector assembly 12 while shielded from the air moving through the louvers l5. Thus, by using the battle 24, one avoids the necessity of placing a second safety thermostat near the reflector assembly 12 which would respond to overheating at the front of the unit.

For the purpose of shutting off the heater 10 in the event that it is accidentally tipped over, it is provided with an automatic safety trip or tip switch 25 (FIGS. 4 and 8) including a switch actuator 26 in the form of a rod slidably mounted in a bushing 26a in the bottom 11 of the housing 11 and adapted to close the contacts of the switch 25 when in engagement with the floor or other surface, the switch 25 opening the electric circuit when the switch actuator 26 comes out of contact with the floor The motor and fan assembly 14, the

scribed hereinafter, the temperature control assembly 19,

including contacts 22a and 22b, and the tip switch 25 are connected in an electrical circuit including the conventional power cord generally indicated at 27 and clearly shown in FIG. 8 of the drawings.

To support the housing 11 from a floor or other surface, the former includes a plurality of legs or feet 28,

preferably in the form of a sheet meta-l strap suitably secured to the bottom 11 of housing If as by rivets 2300 (FIG. 2). As best illustrated in FIG. 2 of the drawings, these legs 28 have forwardly and rearwardly extending portions which serve to prevent placing the heater 10 too close to a wall or other vertical surface, thereby preventing overheating of the heater 10 or the shutting off of the air circulation through the louvers 15 or grille 17.

So that the heater 10 may readily be carried from location to location, it is provide with a retractable handle 29 in the top wall 110 ofthe housing Ill. The handle 29 is of generally U shape with a bight portion 29a thereof forming a hand grip portion and a pair of sides or legs 2% extending from the bight portion 29a and including somewhat narrower portions thereof slidably positioned within a pair of spaced apertures St) in the bottom of a recessed or depressed portion 31 defined in top wall 110 so that when the handle 29 is relased it will fall under the force of gravity into the recessed or depressed portion 31 illustrated in FIGS. 1, 2 and 4 of the drawings. The wide upper portions of the legs 2% (FIG. 2) adjacent the bight portion 2% prevent the handle 29 from dropping into recessed or depressed portion 31 with the bight 2921' in engagement with the bottom of recess 31, thereby permitting the bight portion 29a thereof to be readily gripped by the user at any time. Moreover, the lower ends of the legs 2912 are provided with laterally extending flanges or stops 29c (FIG. 4) which engage the inside of the top wall Me of the housing 11 thereby limiting the maximum withdrawal of the handle 29 relative to the top wall 110 of housing 11.

In order to provide a flush upper surface on the housing 11, and thereby to adapt the heater 10 tobe utilized as an additional piece of furniture such as an end table,

the control knob 23 of the temperature control assembly 19 and the retractable handle 29 are located within the recess 31 defined in the top Wall 110. 'If desired, to improve the appearance of the recess 31 a recessed decorative member 32 nested in the recess 31 and providing a sort of frame arrangement may be provided.

The reflector assembly 12, as illustrated, is preferably formed of sheet metal having a curved heat reflecting surreflector assembly 12 between the end portions 34 there- In order to support the reflector assembly 12 within the housing 11, the opening 18 in the front wall 111) of the housing If; is surrounded or framed by an angular wall portion llg which terminates in a vertically disposed flange 11h, best illustrated in FIG. 3, surrounding the opening 18. The reflector shell 33 and end portions'la i are provided with corresponding flange portions 331) and 34a, respectively, which engage the flange 1111 and are secured thereto by suitable fastening means 35. Preferably, the grille 17 has the periphery thereof sandwiched between the flange 11g and the flanges 33!; and 34a with the fastening means 36 also holding it in position. In

this manner the reflector assembly 12 and grille 17 are mounted to the housing 11 in a very economical manner with no externally visible screws.

In accordance with the present invention, the heating element assembly 13, best illustrated in FIGS. 4 to 7 of the drawings, is a subassembly comprising a resistance heating wire or ribbon 3%, a pair of spaced insulating support blocks 39 and a pair of heater terminal and end supporting members 49. The resistance wire or ribbon 33 is preferably a predetermined length of Nichrome wire or ribbon, or other suitable resistance material, spirally wound around the support blocks 39, which are intended to be separated sufliciently to place a predetermined tension on the resistance wire or ribbon The support blocks 39 are preferably formed of porcelain or similar insulating material and are provided with a plurality of spaced grooves 41 on three sides thereof, as clearly shown in FEGS. 6 and 7 of the drawings. In order to support the electrical terminals 4% for the ribbon 38, each of the support blocks is provided with a slot 42 therein adjacent one end thereof through which a narrow extension 45a of the associated terminal member 4t) extends. Actually each terminal member 49 is of somewhat Z-shaped configuration and has a main body portion 40!) from one end of which the narrow portion 40:: extends and from the other end a portion 400 extends which is welded or otherwise secured, as indicated at 43, to the associated ends 38a and 38b of the ribbon wire 38. When the insulating supports 39 are separated sufliciently to place a tensile force on the resistance ribbon 38, the terminals 40 act to anchor the ends of this resistance wire to supports 39. Tensile force on the element 38 tends to force the narrow portions 40a of terminals 49 into slots 42. Moreover, the slots 42 prevent the terminals 40 from moving beyond the position shown in FIG. 6 of the drawings.

For the purpose of mounting the heating element as sembly 13 within the heater 16 in a manner to maintain the resistance ribbon 38 under tension, the end walls 34 of the reflector assembly 12 are provided with suitable aligned openings 46 generally conforming to the shape of the insulating supports 39 but slightly larger than such supports. Spanning each of these openings 46 is a spring support means or leaf spring 44 of somewhat U-shaped configuration with a central bight portion 44a and end portions 446. The end portions 44b are connected to the bight portion 44a by V-shaped portions 440. The end portions 441; are riveted to the end walls 34 of the refiector assembly 12, as indicated at 45. The insulating supports 39 are suitably secured to the bight portion 44a of the spring supports 44 as by suitable bolts or fastening means 47. In order that the ribbon wire may be completely insulated from the spring support means 44, there preferably is provided an insulating layer 49 of mica or the like which overlies the grooves 41 and is disposed between the supports 39 and spring support means 44. To prevent the supports 39 from being pulled through the openings 46, there preferably is provided for each sup port a sheet metal member 48 fastened by the screws 47 between insulating layer 49 and spring support means 44. This member 48 is, as best shown in FIG. 5, larger than the openings 46. The sheet metal members 48 serve an additional function of radiating heat from the area of the support 39 which, in turn, prevents the spring support means 44 from being overheated. At high temperatures there is a substantial danger of a spring taking a permanent set and losing its resiliency. The sheet metal members 48 may be made of aluminum or other good heat conducting material. Actually, the principal reason for mounting the supports 39 in the openings 46 of end portions 34 is to permit the spring support means 44 to be mounted outside of the reflector assembly 12. It should be understood that the air drawn in by the motor and fan assembly 14 is forced not only through the openings 16in the reflector 33 but also through the spaces in openings 46 not blocked off by the spring supports 39. With provision made for an air passage extending continuously around the supports 39, the air moving by the spring supports 44 and the sheet metal members 48 maintains the spring supports 44 at a reasonable temperature at which'they retain their resiliency. The positioning of the element support structure outside of the reflector assembly 12 also improves the appearance of the heater. It will be observed that since the heating element 38 is spirally wound on the supports 39, the terminal 40 at the left end, viewed in FIG. 7 of the drawings, is adjacent the bottom of the support 39, while the corresponding terminal 40 associated with the support 39 at the right end, as viewed in FIG. 7, is adjacent the top. It will be appreciated that electrical connections can readily be made to the portions of the terminals 40 projecting outside the end walls 34 of the reflector assembly 12. The spring supports 44 tend to provide for parallel movement of the support blocks 39 upon heating and cooling of the heating element 38 with the resultant expansion and contraction, thereby maintaining a predetermined tension on the ribbon 38.

The above-described support for the heating element assembly 13 provides an arrangement in which a minimum of clearance between the reflector assembly 12 and the casing 11 is necessary, thus providing the maximum reflector area. Furthermore, the heating element assembly 13 can be manufactured as a subassembly and the proper tension will be maintained on the heating element even though heating thereof causes substantial expansion.

It will be appreciated that a portable electric heater, according to the present invention, provides for proper clearance of the heating element with the reflector and housing, and at the same time is neat appearing. Moreover, the connection of the heating element tothe terminal members makes possible the Winding of the element on a fixture and the transfer thereof to a heater without having to do any of the winding of the heating element or making connections thereof while the assembly is in the heater thereby providing for economical manufacture of the heater. The spring suspension which connects the insulating members and the reflector provides for parallel motion of the insulating members without any rubbing friction on any of the parts, thereby eliminating noise which would be produced upon heating and cooling of the heating element. Moreover, the construction of the housing and the mounting of the reflector provides for an economical construction. By using the flat porcelain insulating members and springs at the ends, very little space is needed to make connections and, therefore, the reflector can be wide enough to cover the entire front opening of the housing.

While a preferred embodiment of the invention has been described by way of illustration, many modifications will occur to those skilled in the art. It is, therefore, intended in the appended claims to cover all such modifications as fall Within the true spirit and scope of this invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A portable electric heater comprising a housing having an open front including a pair of spaced end walls and a top wall, a reflector assembly in said housing for projecting radiant heat through said open front, said reflector assembly including a pair of spaced end portions, each of said end portions being closely positioned to a respective one of said end walls, elongated aligned openings defined one in each of said end portions, a pair of spaced insulating support means disposed one in each of said aligned openings, a pair of spring means one secured to each of said end portions for holding each of said support means within its associated opening and permitting limited relative movement between said support means, a heating element spirally wound around said spaced support means and extending across said reflector assembly whereby heat produced by said heating element is projected by said reflector assembly through said open front, control means in said housing connected to control said heating means and having a manually settable control knob extending outside of said housing, and retractable carrying handle means secured to said housing.

2. A portable electric heater comprising a housing having an open front and including a pair of spaced end walls and a top wall having a recessed portion, a reflector assembly in said housing for projecting radiant heat through said open front, said reflector assembly including a pair of spaced end portions, each of said end portions being closely positioned toa respective one of said end walls, elongated aligned openings defined one in each of said end portions, a pair of spaced insulating support means disposed one in each of said aligned openings, a pair of spring means one secured to each of said end portions for holding each of said support means within its associated opening and permitting limited relative movement between said support means, a heating element spirally wound around said spaced support means and extending across said reflector assembly whereby heat produced by said heating element is projected by said reflector assembly through said open front, control means in said housing connected to control said heating means and having a manually settable control knob extending outside of said housing into said recessed portion,

and retractable carrying handle means releasable into said recessed portion when said handle means is not in use.

3. A portable electric heater comprising a housing having air passage means including an open front and defined by a pair of spaced end:walls, a reflector assembly in said housing for projecting radiant. heat through said open front having air passage means communicating with the first-mentioned air passage means, said reflector assembly including a pair of spaced end portions, each of said end portions being closely juxtaposed to a respective one of said Walls, aligned openings defined one in each of said end portions, a pair of spaced insulating support :means aligned with each of said openings, a pair of spring means one for each of said support means secured to the outside of said end portions for holding the associated support means within its associated opening and permit ting limited relative movement between said: support means, and a heating element Wound around both of said support means and extending across said reflector assembly and-betweensaid reflector assembly and said open front.

4. A portable electric heater as set. forth in claim 3 wherein each of said spring means comprises a pair of V-sliaped spring portions, each. of said V-shaped spring portions having one leg secured tothe associated support means and the other leg securedto the associated end portion.

5. A heating element assembly for. installation. as a unit into a heater or the like comprising a pair of spaced insulated support means, a pair of terminal means each having a first leg extending through respective ones of said support means and having a second leg, said second legs of each terminal extending toward each other and a heating element wound around both of said support means and extending between said support means, each end of said heating element being wound around the outer surfaces of respective ones of said support means and secured to the said second leg of the associated terminal means.

6. A heating element assembly for installation as a unit into a heater and the like and-comprising a pair of spaced, insulated support membershaving outer surfaces provided with a plurality of slots, a pair of Z-shaped terminal members each having a first leg extending through respective ones ofsaid support members, said first legs having a widened stopportion resting against the confronting surface of the respective support member for positioning said terminal member relative to said support member, the other legs of each of said terminal members extending toward each other, and a heating element positioned in said slots and wound around both of said support members and extending between said support members, each end of said heating element being wound around the outer surfaces of respective ones of said support members and secured to said other legs of respective terminal members.

7. A portable electric heater adapted to be used as an end table and the like and comprising a housing including a horizontal top wall, means defining a recess in said top wall, reflector means in said housing, electric heating means carried by said reflector means, temperature control means in said housing connected to control said electric heating means and having a manually settable control knob extending outside of said housing into said recess, and retractable carrying handle means releasable into said recess when said handle means is not in use, the topmost surface of said knob and the uppermost portion of said handle when said handle is released into said recess being no higher than the means defining the. top of said recess,

8. A portable electric heater comprising an open front housing including a pair of spaced end walls, a reflector assembly in said housing for reflecting radiant energy through said open front, air passage meansthrough said housing including openings in said reflector assembly for convection heating, said reflector assembly including a pair of spaced end portions, each of the said end portions being closely positioned to a respective one of said end walls, means defining an opening in each of said end portions, a pair of insulating support means one disposed in each of said openings, a pair of spring means one for each of said end portions, each spring means supporting its associated insulating support means. within its associated opening and permitting limited relative movement between said insulating support means, said spring means being disposed entirely outside said end portions, and a heating element wound around both said support means and extending across said reflector assembly whereby said reflector assembly reflects radiantenergy produced by said heating element through said open front.

9. The heater of claim 8 in which heat radiating members are interposed between each of said insulating support means and each of said spring means.

10. An electric heater comprising a housing, a reflector assembly mounted in said housing including a pair of spaced end walls, means defining an opening in each of said end walls, said openings in said end walls being aligned with one another, a pair of insulating supports adapted to be supported one in each opening, said insulating supports being so dimensioned as to be freely movable within said openings without touching'said end walls, frictionless means secured to said end walls for supporting each of said insulating supports in the as.- sociated one of said openings, said frictionless means including a spring member for each end wall which permits movement of each of said supports relative to its associated end wall without frictional interengagement of any parts, and a heating element supported by said insulating supports and extending therebetween within said reflector assembly.

11. The electric heater of claim 10 wherein said reflector assembly comprises a generally parabolic reflector shell open at the front with the ends closed by said pair of spaced end walls and wherein the spring member for each end wall is disposed entirely outside said reflector shell.

12. The electric heater of claim 11 wherein heat radiating members are interposed between each of said insulating supports and said spring means.

References f ited by the Examiner UNITED STATES PATENTS 1,074,133 9/ 13 Neustaedter 16-115 2,041,897 5/36 Benson 219-377 2,162,341 6/39 Adam 219--377 2,274,469 2/42 Booth 219-364 2,329,592 9/43 Clemons 219368 2,410,211 10/46 Gough 219-377 2,456,781 12/48 Hardey 219377 2,492,248 12/49 Weingardt 219370 2,505,898 5/50 Jafle et al 16115 X 2,649,753 8/53 Doye 1l6133 X 2,866,073 12/58 Omohundro 219-364 2,986,594 5/61 Ireland 219542 X 3,051,820 8/62 Krichton 219-377 RICHARD M. WOOD, Primary Examiner. MAX L. LEVY, ANTHONY BARTIS, Examiners,

Claims (1)

1. 8. A PORTABLE ELECTRIC HEATER COMPRISING AN OPEN FRONT HOUSING INCLUDING A PAIR OF SPACED END WALLS, A REFLECTOR ASSEMBLY IN SAID HOUSING FOR REFLECTING RADIANT ENERGY THROUGH SAID OPEN FRONT, AIR PASSAGE MEANS THROUGH SAID HOUSING INCLUDING OPENINGS IN SAID REFLECTOR ASSEMBLY FOR CONVECTION HEATING, SAID REFLECTOR ASSEMBLY INCLUDING A PAIR OF SPACED END PORTIONS, EACH OF THE SAID END PORTIONS BEING CLOSELY POSITIONED TO A RESPECTIVE ONE OF SAID END WALLS, MEANS DEFINING AN OPENING IN EACH OF SAID END PORTIONS, A PAIR OF INSULATING SUPPORT MEANS ONE DISPOSED IN EACH OF SAID OPENINGS, A PAIR OF SPRING MEANS ONE FOR EACH OF SAID END PORTIONS, EACH SPRING

Images