US 3646302 A
A quick replacement automatic slack takeup electric cord for small appliances such as lamps, radios and the like, comprising a length of two-conductor plastic lamp cord which is preferably coiled and semipermanently set in a helix, one end of the lamp cord having attached to it a convention two-prong electric plug adapted to be inserted in a wall receptacle. The other end of the two-conductor cord carries and extends into one end of a special elongate receptacle or housing having a socket or recess at its other end, opposite the entrance of the two-conductor cord. The special receptacle has a pushbutton switch and a flat base, the latter enabling it to be supported on a table surface. Within the special receptacle are two metal connector pieces having sharp prongs which are located at the inner end of the socket. The socket is of substantially oblong cross-sectional configuration whereby it is adapted to receive the freshly cut end portion of the original, somewhat flat electric cord from the lamp, which cord has been cut through with a scissors close to the lamp base. The receptacle also has a manually operable lever which is adapted to force the said cut end of the appliance cord laterally against the prongs, causing the latter to pierce the insulation of the appliance cord and to make electrical connections thereto. The switch of the special receptacle has a time delay device which delays the shutoff of the lamp. When the user switches off the lamp, a delay of several moments is experienced before circuit is opened.
Claims available in
Description (OCR text may contain errors)
United States Patent Lehmann [541 ELECTRIC LAMP REPLACEMENT CORD WITH DELAY ACTION SWITCH  Inventor: Herbert G. Lehmann, 5 Kent Road, Easton, Conn. 06612 22 Filed: July 6,1970
21 Appl.No.: 52,614
Primary ExaminerI-I. 0. Jones Attorney-H. Gibner Lehmann /8 l l l 2 [4 1 Feb.29,1972
[5 7] ABSTRACT A quick replacement automatic slack takeup electric cord for small appliances such as lamps, radios and the like, comprising a length of two-conductor plastic lamp cord which is preferably coiled and semipermanently set in a helix, one end of the lamp cord having attached to it a convention two-prong electric plug adapted to be inserted in a wall receptacle. The other end of the two-conductor cord carries and extends into one end of a special elongate receptacle or housing having a socket or recess at its other end, opposite the entrance of the two-conductor cord. The special receptacle has a pushbutton switch and a flat base, the latter enabling it to be supported on a table surface. Within the special receptacle are two metal connector pieces having sharp prongs which are located at the inner end of the socket. The socket is of substantially oblong cross-sectional configuration whereby it is adapted to receive the freshly cut end portion of the original, somewhat flat electric cord from the lamp, which cord has been cut through with a scissors close to the lamp base. The receptacle also has a manually operable lever which is adapted to force the said cut end of the appliance cord laterally against the prongs, causing the latter to pierce the insulation of the appliance cord and to make electrical connections thereto. The switch of the special receptacle has a time delay device which delays the shutoff of the lamp. When the user switches off the lamp, a delay of several moments is experienced before circuit is opened.
12 Claims, 4 Drawing Figures ELECTRIC LAMP REPLACEMENT CORID WITI-I DELAY ACTION SWITCH CROSS-REFERENCES TO RELATED APPLICATIONS l. Copending application of Herbert G. Lehmann, Ser. No.
1 28,762, filed Apr. 15, 1970, entitled Quick Replacement,
BACKGROUND This invention relates to replacement electric cords for small electric appliances such as lamps and radios.
Heretofore the procedure in replacing an electric cord for a lamp or radio required dismantling the device and removing the old electric cord therefrom. A new length of lamp cord was then connected to the interior circuit of the lamp or radio, and threaded through the channels provided, and a two-prong plug was attached to the free end of the new cord. This procedure was not only time consuming but it required a considerable amount of skill. For example, the radio or lamp base would have to be opened, and the old cord pulled out to enable the new cord to be threaded in. Electrical connections, often involving soldering, would have to be made to the circuitry of the radio or lamp. In most circumstances it was found that the original electric cord of the lamp or radio at those locations within the radio casing or lamp pedestal was perfectly sound and actually did not need replacement. Replacement was necessary because of fraying of the external portions of the cord, or because the external portions became dirty, discolored, dried out and brittle, or because it was too long or too short. in most cases, the replacement procedure as set forth above had to be made by a competent electrician or radiotrician, or else a skilled handyman, and this was a distinct disadvantage in that it precluded quick replacement as well as easy replacement, such as would be desired by the housewife doing the work herself, for example. Most lamps have their switches incorporated in the socket shells or shade supports, whereby the user must reach up within the lamp shade and either pull a chain or push or turn a button to operate the lamp. This is not nearly as convenient as having the switch on the base of the lamp; in fact, the lamp-socket-contained switches are often very inconvenient to use. Moreover, where a lamp is to be extinguished in a room prior to the user leaving the room, the extinguishing of the lamp leaves the room in darkness and sometimes the user will stumble over furniture or the like, in walking out of the room. The instant extinguishment of the lamp when the switch is actuated is thus found to be a drawback and hazard.
SUMMARY The above disadvantages and drawbacks of prior switching arrangements for lamps and radios, and prior replacement of original or old electric cords in lamps and radios are obviated by the present invention, which has for one object the provision of a novel and improved quick replacement electric cord which may be virtually instantly installed to replace the frayed, discolored or worn cord of a light-duty appliance, said replacement cord having a time delay switch by which the shutting off of a radio having a light, or of a lamp is delayed several moments to enable the occupant of the room to leave the same while the room is still lighted, thereby avoiding the likelihood of stumbling over furniture or the like.
Another object of the invention is to provide an improved replacement electric cord and delayed action switch as above set forth, which has an inherent slack takeup or helical formation of the cord whereby itis stretchable from a relatively short length to a much greater length so as to automatically take up any slack, making it unnecessary to employ reeling or cord storage links or the like as heretofore utilized.
Still another object is to provide an improved replacement electric cord as above characterized, which has incorporated in it the delay switch in such a location that it is closely adjacent the lamp base and on the adjoining table surface, and is easily and quickly actuated to turn the lamp on or off.
The foregoing objects are accomplished by the provision of a novel replacement electric cord comprising a length of twoconductor plastic insulated lamp wire having attached to one end a conventional two-prong electric plug. The other end of the lamp wire carries a special receptacle fitting which has a delay action pushbutton switch, said special receptacle also having a socket of substantially oblong cross-sectional con-.
figuration and having a pair of contact prongs at the inner end of the socket, adapted to laterally pierce an inserted freshly cut end portion of a flat two-conductor cord as usually provided on lamps, radios and the like. Manually operable means such as a cam lever is provided, to force the cut end of the flat lamp cord against the prongs whereby the cord is impaled thereon, enabling the prongs to electrically connect with the conductors of the cut cord. The prongs are electrically connected with the two-conductor length of wire making up the quick replacement cord. Thus the procedure for replacing the worn appliance cord involves merely cutting the worn cord at a point 1 or 2 inches from the appliance or lamp base and inserting the freshly cut remaining end in the socket of the receptacle fitting of the replacement cord. The cam lever is then operated to lock the cut end portion in place and cause it to be impaled on the connector prongs. This entire operation can be done in several seconds, and requires no skill whatsoever since the average housewife can easily carry out the procedure after reading appropriate simple directions telling her to cut off the old cord with a scissors at a point 1 or 2 inches from the casing or lamp pedestal, and thereafter to insert the remaining cut cord portion in the socket, lastly actuating the lever to lock the appliance cord in place. The special receptacle is provided with a flat base to set on the adjoining table surface adjacent the base of the lamp. The pushbutton switch is provided with a delayed action device which is operative when the switch is shifted to the off position. Thus, the user can turn of? the lamp at a convenient and readily accessible location, and leave the room while the latter is still lighted. When the delayed action device becomes operative the switch will turn off the lamp, subsequent to the user leaving the lighted room.
Still other objects and advantages of the invention reside in the provision of an improved replacement electric cord as above characterized with delay action switch, which is especially simple and inexpensive to produce, and wherein the receptacle fitting comprises relatively few parts which may be economically fabricated and assembled, thereby keeping the entire manufacturing cost of the replacement cord to a low figure; the provision of a helically coiled electric replacement cord arranged to be stretchable so as to automatically take up slack without involving supplemental parts such as reels, takeup links and the like, wherein the helical configuration while inherent in the plastic insulation can take a set" after the final installation, thereby relieving undesired tensions which could pull a light-duty appliance or lamp out of place; and the provision of a replacement electric cord with delay action switch as above characterized, wherein the extent of delay of the switch may be easily and quickly adjusted or varied, so as to suit the convenience of the user.
Other features and advantages will hereinafter appear.
In the accompanying drawings illustrating one embodiment of the invention:
FIG. 1 is a view partly in side elevation and partly in axial section of a replacement electric cord with delay action switch, installed on an electric lamp, the latter being shown in partial section. The delay action switch is illustrated as being in the closed or lamp-lighting position.
FIG. 2 is an axial sectional view of the delay action switch of the replacement cord, shown in the open circuit position.
FIG. 3 is an axial sectional view of the delay action switch immediately after it has been actuated by the user to open the circuit, and prior to the actual opening of the circuit such as will occur after an interval of several moments.
FIG. 4 is a horizontal fragmentary sectional view taken on the line 44 of FIG. 1.
As shown, the present improved replacement electric cord with delay action switch comprises a length of two-wire conductor which in accordance with the invention is preferably although not necessarily coiled into a helical configuration and normally has only a slight tendency to return to its helical shape after considerable stretching. Such tendency may be inherent in the plastic insulation of the cord 10 if it is formed of extruded plastic material and given the helical configuration before the plastic has fully set. Or, ordinary lamp cord may be wound tightly around a 56-inch mandrel rod, the wire opening up to approximately a r-inch coil after winding. By this latter procedure an improved product is had, since the coiled wire after being stretched will take a set in a new position and will not maintain any appreciable constant tension which otherwise might dislodge a light-duty appliance such as a small lamp or small radio.
Secured to one end of the stretchable cord 10 is a conventional two-prong electrical plug 12 having prongs or blades 14 which are electrically connected to the two conductors of the cord 10 in the usual manner. Further, in accordance with the present invention, the other end of the cord 10 is provided with a novel elongate hollow receptacle fitting 16 with delay action switch, one end portion 18 of the fitting 16 receiving the cord 10 and the other end portion 19 of the fitting 16 having a socket 20 of substantially oblong cross-sectional shape, being adapted to receive the end of a flat lamp cord shown at 22. The lamp cord 22 is the original cord of the lamp designated generally by the numeral 24, said lamp having a pedestal portion 26 and a base portion 28. The original lamp cord 22 passes through a sidewall opening 30 of the base portion 28 of the lamp.
As provided by the invention, the receptacle 16 has a pair of prong contacts 38, said contacts having base portions 40 to which the individual conductors 42 of the cord 10 are electrically connected, one through a switching arrangement described below.
The prong contacts 40 are separated by an insulating slab or shoulder 44 which can be cemented in place to one of the easing halves making up the fitting 16. The prong contacts 38 have sharp points 46 extending into the socket 20 of the receptacle l6. Spaced from the sharp points 46 is a projecting wall 48 in the socket 20, and pivotally carried opposite the points 46 is a cam lever 50 which is movable about a pivot pin 52, said lever having a handle portion 54. The lever 50 has a camming portion 56 which is removed from the socket 20 when the lever is in a raised position rotated approximately 90 clockwise from that illustrated in FIGS. 1, 2 and 3. However, when the lever is swung counterclockwise from the raised position to the closed position as shown in the figures, the camming portion 56 of the lever will press against the inserted freshly cut end portion of the original lamp cord 22, causing the latter to be forced against the points 46 of the prong contacts 38 whereby the lamp cord is impaled on the prongs. The two prongs 46 will pierce the insulation of the cord 22 and make electrical contact with the conductors thereof.
Since the prong contacts are connected with the conductors 42 of the replacement cord 10 through a switch shortly to be described, a complete electrical circuit can be established between the replacement cord 10 and the original lamp cord 22. It will be understood that as the lever 50 is swung to its closed position, the inserted end of the original lamp cord 22 would be somewhat bent around the projection 48 of the receptacle casing, and a secure locking action will be had inasmuch as the counterclockwise turning of the lever 50 is halted when it reaches the position of FIG. 1. Any pulls on the lamp cord 22 will merely serve to more securely impale the cord on the prongs 46 and lock it between the projection 48 and the tip of the camming portion 56 of the lever.
The receptacle fitting 16 may be advantageously eonstituted of two halves 58, 60 formed of. molded plastic, said halves being secured together by small rivets 62.
In accordance with the present invention, the receptacle fitting 16 is provided with a delayed action switch designated generally by the numeral 64. From FIG. 4 it will be noted that one of the prongs 40 has an upstanding tab 66 which is received in a suitable recess 67 in the casing half 58 and anchored thereto, said tab being connected with a conductor 42 of the lamp cord 10. The other prong contact 41 extends toward the end 18 of the receptacle fitting, and is provided with a circular, resilient or flexible downwardly offset base portion or contact member 68 and at its extremity with an upstanding contact tab 70. The casing half 58 also has a recess 72 receiving an upstanding portion 74 of a switch blade 76 comprising a circular portion or disk to the underside of which there is affixed a rubber suction cup 78. The anchorage portion 74 of the switch blade 76 is connected with the other conductor 42 of the lamp cord 10. At its center, the circular blade 76 has an upstanding tab 80 which is received in a small bore of a knurled adjustment screw 82, carried by a latchable switch button 84. The adjusting screw 82 is preferably made of insulating material such as nylon, and has a head 86 which is readily accessible at the top exterior of the fitting 16 so that it can be turned for adjustment by the user, for purposes to be described later. The latching button 84 comprises an elongate body portion having internal threads in which the screw 82 is received. The latching button 84 may also be constituted of molded plastic composition, and has a pair of opposite flat sides 88, 90 as seen in FIG. 4. The button 84 is accommodated in a flatted clearance opening 92 provided by the casing halves 58, 60 whereby the button is prevented from turning while being permitted to have vertical movement in the casing. The switch button 84 has a stop lug 94 which is engageable with the top of the casing fitting 16 as seen in FIG. 1, to limit downward movement of the button. Also, the button has a pair of latching shoulders 96, 98, each of which is engageable with the underside of the top wall of the casing 16, to restrict the upward movement of the button 84. The switch blade 76 is adapted to engage the upstanding tab 70 of the switch contact member 68 as seen in FIGS. 1 and 3, thereby to establish a closed circuit between one conductor 42 of the cord 10 (that connected with the switch blade 74, 76) on the one hand and one conductor of the cord 22 (that connected with the switch member 68) on the other hand.
The switch button 84 has a diametric cut 102 in its lower portion, and said lower portion has a threaded bore of similar diameter whereby a fairly tight frictional fit is provided between the switch button 84 and the adjusting screw 82. The diametric cut 102 enables the switch button 84 to have a certain degree of yieldability whereby the screw 82 is tightly pinched yet can be readily adjusted by applying turning force to the adjusting head 86.
Operation of the delay switch as illustrated in FIGS. 1-4 may now be readily understood. Considering FIG. 2, the switch is shown in the open position. The latching shoulder 98 is engaged with the underside of the top wall 100 of the switch casings 58, 60. When the user desires to close the circuit and light the lamp, the button 84 and more specifically the head 86 of the adjusting screw 82 is depressed and shifted to the left as viewed in the figures. This will bring the switch blade 76 downward and flatten and force the suction cup 78 into engagement with the switch member 68 as seen in FIG. 1, thereby to attach itself to the member. The latching shoulder 96 will latch under the top wall 100 of the casing and maintain the switch blade 76 and button 84 in the circuit-closing position. The switch blade 76 is normally biased to a raised position as illustrated in FIGS. 2 and 3, whereas the resilient cooperable switch member 68 is normally biased so as to lie flat as illustrated in FIGS. 1 and 2. The biasing force of the switch blade 76 is much stronger than that of the switch member 68, whereby if the two are joined as by the suction cup 78, the movable blade 76 can raise the stationary member 68 in the manner illustrated in FIG. 3. This is exactly what happens when the switch is to be actuated for extinguishing the lamp. The user merely shifts the switch button 84 laterally from left to right as viewed in the figures, so as to disengage the latching shoulder 96 from the top wall 100 of the casing. The strong biasing force of the movable switch blade 76 will now raise the latter to the position illustrated in FIG. 3, and the suction cup 78 secured to the blade 76 will carry upward with it the lower switch member 68 so that contact is maintained between the switch parts 68, 76 as shown in FIG. 3. After an interval of time depending on the force of the engagement between the suction cup 78 and the switch member 68, the suction of the cup will gradually reduce and the lower member 68 will be released, whereupon it returns to the flat horizontal position of FIG. 2, opening the circuit of the lamp.
By adjusting the screw 82, the initial engagement between the suction cup 78 and the switch member 68 can be made either more or less forceful. The more forceful such engagement is, the longer the delay before the suction deterioriates when the switch is in the open circuit position of FIG. 3 to the point where the switch member 68 is released and returns to its horizontal position, opening the lamp circuit.
It will now be seen from the foregoing that I have provided a novel and improved, easily and quickly attachable accessory lamp or radio cord which has a number of advantages. The accessory can be easily and effectively made to replace the original cord by merely shipping off the latter near the base of the lamp with a scissors, inserting the cut end of the snipped cord in the fitting l6 and actuating the lever 50 to establish electrical connection between the cord 22 and the contact prongs 38. The coiled nature of the cord 10 will take up any slack as the plug is inserted in the wall receptacle. Thus there will not exist the long and unsightly, dust-catching random length of wire which has heretofore characterized electric lamps or radios. The receptacle fitting 16 will rest on the table surface adjacent the lamp base 28, and the user can now turn the lamp on and off by merely actuating the button assemblage 82, 84. When the lamp is to be extinguished, the release of the button from the FIG. 1 position to the FIG. 3 position will effect a delay in the opening of the circuit since the suction cup 78 carries upward with it the resilient switch member 68. After a period of several seconds or minutes the suction in the cup 78 will deteriorate to the point where the switch member 68 returns to the open-circuit position of FIG. 2 by virtue of its resilience.
The present improved lamp cord accessory with delayed switch as above set forth is seen to comprise relatively few parts, and to be easily and economically producible. Moreover, a simple adjustment and be effected by virtue of the screw 82, whereby the extent of delay of the circuit opening interval may be easily varied to suit the particular conditions of use.
Variations and modifications are possible without departing from the spirit of the invention.
1. A replacement electric cord for small lamps, comprising in combination:
a. a length of two-conductor electric cord,
b. a two-prong electric plug affixed to one end of said electric cord and having prong-type contacts electrically connected respectively to the conductors of the electric cord,
c. an electric receptacle fitting attached to the other end of the electric cord, said receptacle fitting having a socket of substantially oblong cross-sectional configuration for receiving the cut end portion of a similar section cord of the lamp,
d. said receptacle fitting having a pair of sharp prongs disposed at the inner end of the socket and electrically connected respectively to the conductors of said electric cord, and
e. manually operable means carried by the receptacle fitting and adapted to force laterally against the sharp prongs the end portion of said out electric cord of said lamp when said lamp cord is inserted in said socket, whereby the sharp prongs pierce the insulation of the inserted lamp cord and make electrical contact to the conductors thereof,
f. switch means carried by said receptacle fitting,
g. connections between said switch means and the electric cord and a prong of the receptacle fitting, for controlling the electrical circuit of the lamp,
h. a delay device to effect delayed opening of the electrical circuit of said switch means when the latter is actuated to open the lamp circuit.
2. A replacement electric cord as defined in claim 1,
a. said switch means comprises an upstanding pushbutton and an electrical contact actuated by the pushbutton, and
b. a base carried by the receptacle fitting, adapted to rest on a table surface adjacent the lamp, thereby to facilitate actuation of the pushbutton.
3. A replacement electric cord as defined in claim 2, and
a. cooperable releasable latch means on the pushbutton and receptacle fitting, for maintaining the pushbutton in a depressed position,
b. means biasing the pushbutton to a raised, nondepressed position on the receptacle fitting,
c. said switch means including a second electrical contact cooperable with the first-mentioned electrical contact,
d. said delay device comprising a suction cup connected with said pushbutton and engageable with said second electrical contact to restrict opening movement of the pushbutton.
4. A replacement electric cord as defined in claim 3,
a. said firstand second-mentioned electrical contacts being resilient and movable in like, opposite directions.
5. A replacement electric cord as defined in claim 4,
a. the first-mentioned electrical contact is stiffer and stronger than the second-mentioned contact,
b. said suction cup tying together and causing simultaneous movement of the resilient contacts in the same directions during opening movement of the pushbutton,
c. said contacts being biased in opposite directions,
(I. said suction cup eventually effecting release of the second-mentioned contact to enable the latter to return to its initial position under its bias.
6. A replacement electric cord as defined in claim 3, and
a. an adjusting screw threaded into said pushbutton and adjustable axially with respect thereto,
b. said screw changing the relative positions of the pushbutton and first-mentioned electrical contact,
c. said suction cup being carried by said first-mentioned electrical contact.
7. A replacement electric cord as defined in claim 5, and
a. an adjusting screw threaded into said pushbutton and adjustable axially with respect thereto,
b. said screw changing the relative positions of the pushbutton and first-mentioned electrical contact,
c. said suction cup being carried by said first-mentioned electrical contact.
8. A delay-off electric switch comprising, in combination:
a. a pair of movable cooperable electrically conducting leaf springs disposed in spaced parallel insulated relation and constituting switch parts adapted to close and open a circuit by respectively engaging and disengaging each other, and
b means causing simultaneous similar movements of said leaf springs when engaged, for delaying the disengagement thereof when one spring is moved in a direction away from the other, said means including a suction cup on one spring, acting on the other to hold the leaf springs together for a predetermined time after the application of a separating force thereto.
9. A delay-off electric switch as in claim 8, and further including:
a. adjustment means for effecting initially either a greater or a lesser vacuum as produced by the suction cup, to cause either a greater or a lesser delay to be effected thereby.
10. A delay-off electric switch as in claim 9, wherein:
a. the adjustment means comprises a tumable screw connected to cause either a greater or a lesser flattening of the suction cup when it is initially made operative.
11. An electric switch as in claim 8, in combination with:
a. an electrical receptacle fitting in which the leaf springs are mounted and carried,
b. said receptacle fitting having a socket of substantially oblong cross-sectional configuration for receiving the cut end portion of a similar section cord of a lamp.
c. said receptacle fitting having a pair of sharp prongs disposed at the inner end of the socket and one of said sharp prongs being electrically connected to one of said leaf springs, and
d. manually operable means carried by the receptacle fitting and adapted to force laterally against the sharp prongs the end portion of said cut electric cord of said lamp when said lamp cord is inserted in said socket, whereby the sharp prongs pierce the insulation of the inserted lamp cord and make electrical contact to the conductors thereof.
12. An electric switch as in claim 8, in combination with:
a. an electric fitting comprising a housing in which the leaf springs are mounted,
b. said housing having a socket for receiving the cutoff end of a lamp cord,
c. connection means connected to one of said leaf springs and adapted to be forced into contact with a conductor of the lamp cord when inserted in said socket, and
d. manually operable means for rendering operative said connection means to effect said contact with said conductor.