US 2425790 A
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Description (OCR text may contain errors)
1947. R. A. FLETCHER 2,425,790
BED SWITCH Filed Jan. 12," 1946 ROLAND A.FLETCHER,
INVENTOR ATTORNEY Patented Aug. 19, 1947 UNITED STATES PATENT OFFICE BED SWITCH Roland A. Fletcher, San Diego, Calif.
Application January 12, 1946, Serial No. 640,822
This invention relates to weight-actuated switches and is particularly applicable for use under a leg of a bed for turning on a night lamp in response to the lessening of the Weight on th leg when an occupant of the bed gets up.
An object of the invention is to provide a compact and reliable switch structure so shaped that the actuating member thereof can be placed under one leg of a bed without raising the leg materially above the level of the floor.
Another object is to provide a weight-actuated switch structure that can be adjusted to function under beds of different weights and for people of different weights.
Another object is to provide a compact and rugged unit consisting of a Weight-actuated switch and a lamp controlled thereby which unit can be placed partially under and partially adjacent the leg of a bed for providing illumination when an occupant of the bed gets up.
Other more specific objects and features of the invention will become apparent from the description to follow of a particular embodiment of the invention as illustrated in the drawing, in which:
Fig. 1 is a longitudinal, vertical section through a switch unit in accordance with the invention;
Fig. 2 is a View partially in plan and partially in section, the section being taken along the line II-II of Fig. 1;
Fig. 3 is a cross-section taken along the line III-III in Fig, 1; and
Fig. 4 is a schematic diagram showing the elec trical circuit of the device.
Referring first to Figs. 1, 2 and 3, the device shown comprises a housing l containing a switch for controlling a lamp H which may be mounted on top of the housing, while projecting from one side of the housing In is a member l2 adapted to be placed under a leg [3 of a bed and to respond to variations in the weight of the leg l3 to actuate the switch and turn the lamp on and oil.
The housing [0 may consist of a metal stamping having end-walls l4 and t5, side-walls I6 and I1, and a top-wall 18, all formed in one piece. The bottom-wall I9 is formed by a separate piece of metal and extends beyond the end-wall l as a strip 20 that is doubled back on itself as indicated at 2| and extended almost back to the endwall I5 to constitute the member [2. The upper portion 22 of this strip may be indented near its middle as indicated at 23 to receive the foot of the leg I3 and prevent the foot from slipping off the member l2.
The member 12 is preferably formed of relatively heavy, elastic metal so that it has substantial resistance to bending by the weight of the leg I3. However, it is usually undesirable to make the number I2 sufiiciently stiif to fully support the weight, and it is preferably reinforced by a helical compression spring 24, which is interposed between the sections 20 and 22 of member 12 and is centered by the depressed portion 23 of the section 22.
The end of the section 22 adjacent the endwall E5 of the housing It] is provided with a switch-actuating tongue 25 of insulating material, which extends through a slot 26 in the endwall l5, into the housing H1. The tongue 25 may be secured to section 22 by rivets 21.
The contact mechanism within the housing l0 comprises a pair of leaf springs 28 and 29 positioned one above the other and both supported at one end. Thus the lower leaf spring 29 rests upon an insulating block 30 which lies upon the bottom-wall I9. A second block of insulating materia1 3i rests upon the spring 29 and separates it from the spring 28. A third block 32 of insulating material rests upon the spring 28 and extends upwardly through the top-wall I8 of the housing l0 and is provided with a shoulder 32! which engages the wall I 8. A screw 33 extends through an aperture provided therefor in the bottom-wall l9 and is threaded into the insulating block 32. When this screw 33 is tightened it compresses the pile consisted of the block 30, the spring 29, the block 3|, the spring 28, and the block 32 together, and also holds the right end of the bottom-wall [9 against the housing I 0. An insulating bushing 34 surrounds the screw 33 within the blocks 30 and 3|, to insulate the screw from the contact springs 28 and 29.
As best shown in Fig. 3, the block 32, in addition to functioning as a structural member to support the leaf springs 28 and 29, also functions as an electrical receptacle. Thus it has a pair of slots 35 and 36 which open through its upper surface into recesses 31 and 38, in which spring contacts 39 and 40 are located.
The device is adapted to be energized over a two-conductor lamp cord from a common source of lighting current, and to this end a pair of conductors 4| and 42 are shown entering the endwall 14 of the housing through an insulating bushing 43 positioned in an aperture in the wall M. One of these conductors, 4|, is connected directly to the lower leaf spring 29, and the other conductor, 42, is connected directly to the receptacle contact 40. The other receptacle contact 39 is connected by a wire 45 (Fig. 3) to the other leaf spring 28; It will be observed, therefore, that,
when the contact springs 28 and 29 are closed, a circuit is completed from the supply conductors 4| and 42 to the two contacts 39 and 40 of the receptacle, and a lamp connected to the receptacle will be lighted.
As shown in Fig. 1 the lamp II is screwed into a standard form of receptacle 41 which has a pair of prongs extending through the slots 35 and 36 in the receptacle and making electrical contact with the contacts 39 and 40.
If it is desired to have the lamp in some other location, the receptacle 41 can [be removed, and an extension cord plugged in.
The contact springs 28 and 29 are provided near their outer ends with contacts 281 and 29| respectively. The lower contact spring 29 is extended beyond the end of the spring 28 and is adapted to be engaged by the end of the insulating tongue 25. The upper spring 28 normally bears against an insulating tip 50 on the lower end of a screw 51 which is threaded through the top-wall l8 of the housing and is provided with a handle .52 on its upper end.
The device functions as follows:
When the leg l3 of the .bed which is to control the switch is rested in the recess 23 in the upper section 22 of the member l2, the leg depresses the tongue 25 to a pre-determined extent, dependent upon the weight of the bed. When the bed is not occupied, the contacts 28,! and 29.! should be closed, but they should be open when a person is in the bed. Adjustment to provide for the indicated operation is readily obtained by turning the adjusting screw 5|, while the bed is empty, until the contacts 28I and 29! are just closed, as indicated by lighting of the lamp ll. With this adjustment, any additional weight imposed on the leg l3, as by a person getting into bed, is surficient to break the contacts and extinguish the lamp. However, should the person leave the bed at any time during the night the reduction in the weight on the leg 13 permits the tongue 25 to move upwardly suflicient to again close the contacts 281 and 29,] and light the lamp II.
The arrangement has the practical advantage of providing an automatic night lamp which always lights in response to an occupant of the bed leaving it, without the necessity of the occupant groping around in the dark to find a light switch.
By means-of the adjustment screw 5| the switch can .be adjusted to function reliably regardless of the weight of the bed with which it is used and regardless of the weight of the occupant of the bed. Furthermore, if there is more than one occupant of the bed, the switch can be adjusted to light the lamp in response to rising of only one of the occupants.
A particular advantage of the structure is that it provides a rugged and reliable sprin mechanism for supporting the weight of the leg, which structure is compact vertically so that it does not lift the leg high off the floor. The elevation of the leg by the device is sufiiciently small to be permissible without correspondingly raising the other three legs off the floor. However, if desired, small supports of the same height as the spring section 22 may be placed under the other legs of the bed to maintain all four :corners of the bed at the same level.
Although for the purpose of explaining the invention, a particular embodiment thereof has been described in substantial detail, various .departures from the exact construction disclosed and described can be made without departing from the invention, and the latter is to be limited only to the extent set forth in the appended claims.
1. A device of the type described comprising: a casing defining an enclosure and consisting of a bottom-wall and separate cover means constituting side and top walls, said bottom-wall extending laterally beyond said cover member on one side thereof; the extended portion of said bottom-wall being folded back on itself and having a free end extended toward said cover member at a level below the top of said cover member, switch means in said casing; and means on said free end for actuating said switch means.
2. A device of the type described comprising: a casing defining an enclosure having an opening in one side thereof; a base member extending laterally from the bottom of said casing on said one side therof; a weight-supporting vertically defiectable member positioned above said base member and secured at its outer end to the outer end of said base .iember; the inner end of said defiectable member extending through said opening into said casing; and switch means in said casing operable in response to vertical movment of the inner end of said deflectable member; said switch means comprising a pair of leaf spring members positioned one above the other and having normally closed electrical contacts; means coupling the lower spring member to said inner end. of the defleotable member whereby .downward movement or" the latter moves said lower spring member downwardly; and means for adjusting the upper spring member vertically to vary the vertical position of said defiectable member which said contacts break.
3. A device of the type described comprising: a casing defining an enclosure having an opening in one side thereof; a base member extending laterally from the bottom of said casing on said one side thereof; :a weight-supporting vertically deflectable member positioned above said base member and secured at its outer end to the outer end of said base member; the inner end of said defleetable member extending through said opening into said casing; and switch means in said casing operable in response to vertical movement of the inner end of said deflectable member; said switch means comprising a pair of leaf spring members positioned one above the other and having normally closed electrical contacts; means coupling the lower spring member to said inner end or the deflectable member whereby downward movement of the latter moves said lower spring member downwardly; and an adjusting screw threaded through the wall of said casing and contacting the upper spring member for vertically adjusting said upper spring member to vary the vertical position of said deflectable member at which said contacts break.
4. A device of the type described comprising: a casing defining an enclosure and consisting of a bottom wall and separate cover means constituting side and top walls, said bottom wall extending laterally beyond said cover member on one side thereof; the extended portion of said bottom wall being folded back on itself and having .a free end extended toward said cover memher at a level below the top of said cover member; switch means in said casing; means on said free end for actuating said switch means; and means for adjusting said switch means tovary the movement of said free end requiredto actuate said switch means.
5. A switch responsive to occupation ofa bed REFERENCES CITED comprising: deflectable spring means adapted to ,b interposed b t th leg of a bed and th The following references are of record in the floor and deflectable in response to variations in file Of h p nt Weight on the bed; a pair of normally closed 5 UNITED STATES PATENTS electrical contact members; means for shifting one of said contact members in circuit-opening Number N Date direction in response to the deflection of said 2,135,051 Dfilgle 1939 spring means resulting from an increase in 2,142,599 Blndel 1939 Weight on said bed; and means for varying the 1 2,113,320 MCEWBII M y 1933 magnitude of said deflection required to open 2,107,333 n b. 1933 said ontact members Wartmann May 13, 1,389,365 Kline Aug. 30, 1921 ROLAND A. FLETCHER]. 35,223 Hexamer Feb. 2, 1886