US2976524A - Electric signalling system - Google Patents

Electric signalling system Download PDF

Info

Publication number
US2976524A
US2976524A US758377A US75837758A US2976524A US 2976524 A US2976524 A US 2976524A US 758377 A US758377 A US 758377A US 75837758 A US75837758 A US 75837758A US 2976524 A US2976524 A US 2976524A
Authority
US
United States
Prior art keywords
unit
conductor
plug
prongs
prong
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US758377A
Inventor
Ivan H Wall
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US758377A priority Critical patent/US2976524A/en
Application granted granted Critical
Publication of US2976524A publication Critical patent/US2976524A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • GPHYSICS
    • G08SIGNALLING
    • G08BSIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B3/00Audible signalling systems; Audible personal calling systems
    • G08B3/10Audible signalling systems; Audible personal calling systems using electric transmission; using electromagnetic transmission

Definitions

  • the invention further contemplates both a one-way system and a two-way system capable of actuating audible signals from a remote point.
  • a further object of the invention resides in the signalling system having one unit constructed as a plug-in unit in a conventional outlet receptacle and with the unit embodying a conventional transformer, a signalling device and a plurality of receptacles coupled with conductors of varying lengths and with the conductors being provided at their opposite ends with a pronged plug and a prong receiving plug adapted to be detachably connected to a switch device having prongs and with the switch device being normally in the form of a desk signal and through the medium of which the plug-in unit may be located at one remote point, while the desk switch device may be located at another remote point and whereby an audible signal may be actuated in the plug-in device.
  • a further object of the invention resides in the two-' being connected to a pair of rearwardly extending prongs that engage within the usual wall outlet receptacle and also, with the casing being provided with an apertured tongue whereby the housing may be fixed against accidental displacement from the receptacle by the passage of a screw or the like commonly employed to retain the.
  • Figure 1 is a perspective view of the several units combined to constitute a one-way signal system
  • Figure 2 is a perspective view of the several elements constituting a two-way signal system
  • Figure 3 is a diagrammatic wiring illustration for the system embodied in the one-way signal mechanism and,
  • Figure 4 is a diagrammatic wiring illustration of the system embodied in the two-way signal system.
  • Atcritfi unit 5 may be formed of plastic, hard rubber or any other desirable material to form a housing for a transformer 8, a buzzer or other audible signal device 9 and a plurality of female plugs 10, .11, 12, 13, 14 and 15.
  • the housing 5 carries a' pair of rearwardly extending fiat prongs 16 that are connected to a transformer 8.
  • the prongs 16 are conventional in construction and are adapted to be electrically connected to a conventional Wall outlet receptacle, not shown.
  • the housing 5 is also provided with an upstanding tongue 17 that is apertured at 18 for the passage of one of the screws normally employed to retain the cover plate of the receptacle in position and with the screws jointly serving to retain the housing 5 in its plugged-in engagement which acts against accidental displacement.
  • the unit 7 embodies any desirable ornamental desk switch housing, that may be formed of suitable material.
  • the unit 7 is provided with forwardly projecting prongs 19, 20 and 21.
  • the prongs 19 and 20 have connection with spring contact arms 22 and 23, having contact points 24.
  • the contact points 24 are moved to contacting rela? tion under the influence of a button 25 that projects through the upper surface of the unit 7 and whereby the switch may be actuated to establish a flow of electricity.
  • a cable 26 carrying conductors 27, 28 and 29.
  • the conductors 27, 28 and 29 at one end are connected to prongs 30, 31 and 32 that are embodied within a suitable hard rubber or the like plug device, not shown.
  • the prongs 30, 31 and 32 have a spacing equal to the spacing of the plugs 10, 11 and 12 and whereby the prongs may be engaged therein in assembling the system.
  • the opposite ends of the wires 27, 28 and 29 terminate in female plugs 33, 34 and 35, fixed with respect to a molded plug 36 and with the plugs 33, 34 and 35 being spaced in accordance with the prongs 19, 20 and 21 and whereby the cable may be connected to the unit 7 without the use of tools or other fastening means.
  • the unit '5 is mounted at a point whereat the audible signal may be heard.
  • the unit 5 may be located in one ofiice, while the unit 7 may be located in an adjacent ofl'ice, close to a telephone or switchboard and whereby a person may be advised of a telephone call or other service.
  • the cable 6 is trained to the desired point after connecting the prongs 30, 31 and 32 to the plugs 10, 11 and 12. It will be obvious, that the cable will be manufactured in varying lengths in accordance with the necessity of use.
  • a unit 5a is substantially identical to the unit 5, embodying the transformer 8, the buzzer 9, the plugs 10, 11, 12, 13, 14 and 15.
  • the plugs 12 and 13 are connected together by a conductor 41.
  • the plugs 15 are blank and merely furnish a pilot for the proper insertion of the prongs 30, 31 and 32.
  • the unit 7 is employed as before and in addition, there has been em ployed a second switch element '42.
  • the switch element 7 of this latter form embodies the switch blades 22 and 23 having the contact points 24.
  • the blades 22 and 23 are connected to prongs 19 and 20.
  • the unit 7 of this form of the invention is connected by a cable 6a, embodying the conductors 27, 28 and 29 as before, having at one end the prongs 30, 31 and 32 while at the other end, the conductors terminate in the plug 36 having the female plugs 33, 34 and 35.
  • the switch blades 43 and 44 having the contact points 45.
  • the blades 43 and 44 are connected to projecting prongs 46 and 47.
  • an audible signal device such as a buzzer 48.
  • One side of the buzzer 48 is connected to the prong 47 by a conductor 49, while the opposite side ofthe buzzer 48 is connected to a prong 50 by a conductor 51.
  • the usual button 52 is provided to actuate the contact points 45 to 'a circuit-making position.
  • a cable 6b carrying conductors 53, 54, and 55
  • the cable at one end is provided with a plug having prongs 56, 57 and 58 for pronged engagement within the plugs 10, 11 and 12,
  • the cable at its opposite end is provided with a plug having the female plugs 56', 57' and 58', for engagement with the prongs 46, '47 and 50.
  • the prong 21 of the unit 7 is a blank prong and merely serves in the same capacity as the plugs 15st the units 5 and 5a.
  • the button 25 When the audible signal 48 is to be actuated, the button 25 is actuated, closing the contacts 24 and establishing a flow of electricity through a conductor 59 from the transformer 8 to the plug 14, through the conductor 28, plug 34 and prong 29, through the switch blades 23 and 22, prong 19 and plug 33, conductor- 27, prong 30 and plug 13, conductor 4'1, plug 12 and prong 58, conductor 55, conductor 58 and prong 50, conductor 51, through the signal device -45', conductor 49, prong 47 and plug 57', conductor 54, prong 57 and plug 11 and conductor 39 back to the transformer 8 establishing a flow of electricity through the audible signal 48, calling attention to an adjacent person.
  • the person to receive the signal would thus have the unit 5a and the unit 7 located at a convenient point, while the person at the remote point, such as the person receiving a telephone message would have the unit 42 adjacent or in a convenient position.
  • the person at the remote point such as the person receiving a telephone message would have the unit 42 adjacent or in a convenient position.
  • the operator actuates the button 52 and establishes a flow of current through the buzzer 9 and, with the unit 7 being adjacent to the unit 5a, a person may, by pressing the button 25, actuate the signal device 48, calling attention to the fact that the other individual at the remote point is advised that his service is required by the other individual.
  • the system can be flexible in that it provides basically a one-way signal system while in the other, with an additional cable, it functions to establish a two-way signal system.
  • a signalling system of the character described that comprises a main unit composed of a housing having therein a step-down transformer and an audible signal device, prongs connected to the high voltage side of the transformer and that projects through a rear wall of the housing for pronged engagement into a wall receptacle that constitutes the source of high voltage electrical energy, the said housing provided with two sets of three female plugs, a central plug of each group of female plugs being connected to the low voltage side of the transformer, a conductor connecting the two next adjacent female plugs of each group, a conductor leading from the low voltage side of the transformer to the signal device, a conductor leading from the opposite side of the signal device to an outer-most female conductor of one group, a pair of remote control devices that include each a housing, a circuit closing switch in each housing, means projected above the housings for actuating the switches, one remote control device also including an audible signal device, the last named control device being provided with three projecting prongs, the central prong being connected to one side of the adjacent
  • each of the cables at one end being provided with a three-pronged plug and at its opposite end with a plug having three female sockets, the said pronged plugs having pronged engagement into the female sockets of the main unit and the female sockets of each cable having engagement with the respective prongs of each control device, the first named control device establishing a flow of electricity through the signal device of the main unit when the switch is closed, the second named control device establishing a flow of electricity from the transformer to the signal device of the first named control unit.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Details Of Connecting Devices For Male And Female Coupling (AREA)

Description

March 21, 1961 l. H. WALL 2,976,524
ELECTRIC SIGNALLING SYSTEM Filed Sept. 2, 1958 1' s2 4 ENVENTOR.
4059/ N m S6 55 T \VAN \LWALL.
FiG.4:
A TTORNEY ELECTRIC IGNALLING SYSTEM Ivan H. Wall, 5900 Garden Ave., West Palm Beach, Fla.
Filed Sept. 2, 1958, Ser. No. 758,377
1 Claim. (Cl. 340-311) This invention relates to improvements in signalling systems and has particular reference to a novel form of system wherein the several units are actuated by the conventional 110 volt system, requiring no wiring that would require the services of a qualified electrician.
The invention further contemplates both a one-way system and a two-way system capable of actuating audible signals from a remote point.
A further object of the invention resides in the signalling system having one unit constructed as a plug-in unit in a conventional outlet receptacle and with the unit embodying a conventional transformer, a signalling device and a plurality of receptacles coupled with conductors of varying lengths and with the conductors being provided at their opposite ends with a pronged plug and a prong receiving plug adapted to be detachably connected to a switch device having prongs and with the switch device being normally in the form of a desk signal and through the medium of which the plug-in unit may be located at one remote point, while the desk switch device may be located at another remote point and whereby an audible signal may be actuated in the plug-in device.
A further object of the invention resides in the two-' being connected to a pair of rearwardly extending prongs that engage within the usual wall outlet receptacle and also, with the casing being provided with an apertured tongue whereby the housing may be fixed against accidental displacement from the receptacle by the passage of a screw or the like commonly employed to retain the.
cover plate upon the receptacle.
Novel features of construction and operation of the device will be more clearly apparent during the course of the following description, reference being had to the accompanying drawings wherein has been illustrated the preferred forms of the device and wherein like characters of reference are employed to denote like parts throughout the several figures.
In the drawings:
'Figure 1 is a perspective view of the several units combined to constitute a one-way signal system,
Figure 2 is a perspective view of the several elements constituting a two-way signal system,
Figure 3 is a diagrammatic wiring illustration for the system embodied in the one-way signal mechanism and,
Figure 4 is a diagrammatic wiring illustration of the system embodied in the two-way signal system.
Referring specifically to the drawings and particularly to Figures 1 and 3, the several units embodied in the system are designated by the numerals 5, 6 and 7. The
atcritfi unit 5 may be formed of plastic, hard rubber or any other desirable material to form a housing for a transformer 8, a buzzer or other audible signal device 9 and a plurality of female plugs 10, .11, 12, 13, 14 and 15. The housing 5 carries a' pair of rearwardly extending fiat prongs 16 that are connected to a transformer 8. The prongs 16 are conventional in construction and are adapted to be electrically connected to a conventional Wall outlet receptacle, not shown. The housing 5 is also provided with an upstanding tongue 17 that is apertured at 18 for the passage of one of the screws normally employed to retain the cover plate of the receptacle in position and with the screws jointly serving to retain the housing 5 in its plugged-in engagement which acts against accidental displacement.
The unit 7 embodies any desirable ornamental desk switch housing, that may be formed of suitable material. The unit 7 is provided with forwardly projecting prongs 19, 20 and 21. The prongs 19 and 20 have connection with spring contact arms 22 and 23, having contact points 24. The contact points 24 are moved to contacting rela? tion under the influence of a button 25 that projects through the upper surface of the unit 7 and whereby the switch may be actuated to establish a flow of electricity.
Adapted tobe connected to the units 5 and 7, is a cable 26 carrying conductors 27, 28 and 29. The conductors 27, 28 and 29 at one end are connected to prongs 30, 31 and 32 that are embodied within a suitable hard rubber or the like plug device, not shown. The prongs 30, 31 and 32 have a spacing equal to the spacing of the plugs 10, 11 and 12 and whereby the prongs may be engaged therein in assembling the system. The opposite ends of the wires 27, 28 and 29 terminate in female plugs 33, 34 and 35, fixed with respect to a molded plug 36 and with the plugs 33, 34 and 35 being spaced in accordance with the prongs 19, 20 and 21 and whereby the cable may be connected to the unit 7 without the use of tools or other fastening means.
In the use of this form of the invention, the unit '5 is mounted at a point whereat the audible signal may be heard. For instance, as in an ofiice, the unit 5 may be located in one ofiice, while the unit 7 may be located in an adjacent ofl'ice, close to a telephone or switchboard and whereby a person may be advised of a telephone call or other service. With the unit 5 in position, the cable 6 is trained to the desired point after connecting the prongs 30, 31 and 32 to the plugs 10, 11 and 12. It will be obvious, that the cable will be manufactured in varying lengths in accordance with the necessity of use. With the cable 6 having been trained to the desired point, it is connected with the unit 7 through the medium of the plugs 33, 34 and 35 engaging the prongs 19, 20 and 21. The system is now in operative assembled relation. Assuming, that an operator wishes to communicate the fact that a personat the remote point of the unit 5 is desired to answer the telephone, the button 25 is pressed, closing the contacts 24 at which time, electricity flows from the contact 36 of the transformer 8, through a conductor 37,
to the buzzer 9, through a conductor 38, to the plug 10,
through the conductor 27, plug 33 and prong 19, through the switch arms 22 and 23, the prong 2G, plug 34, conductor 28, prong 31, prong 11 and a conductor 39, to a contact 40 of the transformer 8, establishing a flow of electricity through the buzzer 9, causing the same to become audible. The plugs 13, 14 and 15 in this particular system have no function in this unit 5 and it will be apparent, that the unit 5 is identical in construction to a corresponding unit to be described in connection with a two-way signal system. The system illustrated in Fig- -ures 1 and 3 thus provide a very desirable signal mecha- Patented Mar. 21, 1961*,
thus greatly facilitating the installation of the signal sys- I tern without the necessity of installing wiring, making connections and the like that has heretofore been necessary in devices of this nature and the only tool required, would be a screw driver for actuating the screw that passes through the tongue 17.
In the form of the invention illustrated in Figures 2 and 4, a unit 5a is substantially identical to the unit 5, embodying the transformer 8, the buzzer 9, the plugs 10, 11, 12, 13, 14 and 15. The contact 36 as before, leads to the buzzer 9, by the conductor 37, while the contact 40 leads to the plug 11 through the conductor 39, while the conductor 38 leads to the plug As shown in both Figures 3 and 4, the plugs 12 and 13 are connected together by a conductor 41. In each instance, the plugs 15 are blank and merely furnish a pilot for the proper insertion of the prongs 30, 31 and 32. In this latter form of the invention, the unit 7 is employed as before and in addition, there has been em ployed a second switch element '42. The switch element 7 of this latter form embodies the switch blades 22 and 23 having the contact points 24. The blades 22 and 23 are connected to prongs 19 and 20. The unit 7 of this form of the invention is connected by a cable 6a, embodying the conductors 27, 28 and 29 as before, having at one end the prongs 30, 31 and 32 while at the other end, the conductors terminate in the plug 36 having the female plugs 33, 34 and 35. Now, with respect to the unit 42, there has been provided the switch blades 43 and 44, having the contact points 45. The blades 43 and 44 are connected to projecting prongs 46 and 47. Also disposed within the unit 42, is an audible signal device, such as a buzzer 48. One side of the buzzer 48 is connected to the prong 47 by a conductor 49, while the opposite side ofthe buzzer 48 is connected to a prong 50 by a conductor 51. The usual button 52 is provided to actuate the contact points 45 to 'a circuit-making position.
Extending between the units 5a and the unit 42, is a cable 6b, carrying conductors 53, 54, and 55, the cable at one end is provided with a plug having prongs 56, 57 and 58 for pronged engagement within the plugs 10, 11 and 12, the cable at its opposite end is provided with a plug having the female plugs 56', 57' and 58', for engagement with the prongs 46, '47 and 50. The prong 21 of the unit 7 is a blank prong and merely serves in the same capacity as the plugs 15st the units 5 and 5a.
In the use of this form of the invention, when the buzzer 9 is to be actuated, the button 52 is pressed, actuating the contacts 45 to close the circuit, at which time current will flow through the conductor 37, buzzer 9, conductor 38, conductor 53 to switch blade 43, through the switch blade 44, conductor 54, conductor 39 and back to the contact 4% of the transformer 8, establishing a how of current to the buzzer 9, causing it to sound. When the audible signal 48 is to be actuated, the button 25 is actuated, closing the contacts 24 and establishing a flow of electricity through a conductor 59 from the transformer 8 to the plug 14, through the conductor 28, plug 34 and prong 29, through the switch blades 23 and 22, prong 19 and plug 33, conductor- 27, prong 30 and plug 13, conductor 4'1, plug 12 and prong 58, conductor 55, conductor 58 and prong 50, conductor 51, through the signal device -45', conductor 49, prong 47 and plug 57', conductor 54, prong 57 and plug 11 and conductor 39 back to the transformer 8 establishing a flow of electricity through the audible signal 48, calling attention to an adjacent person. The person to receive the signal would thus have the unit 5a and the unit 7 located at a convenient point, while the person at the remote point, such as the person receiving a telephone message would have the unit 42 adjacent or in a convenient position. With this particular system it is possible for a person to advise another at a remote point that service is required by having the unit 42 at a selected point while the unit 5a is at a remote point. Thus, when it is desired that a person answering the phone at a remote point, the operator actuates the button 52 and establishes a flow of current through the buzzer 9 and, with the unit 7 being adjacent to the unit 5a, a person may, by pressing the button 25, actuate the signal device 48, calling attention to the fact that the other individual at the remote point is advised that his service is required by the other individual. It will therefore be seen that with a unit such as that illustrated at 5 and 5a, the system can be flexible in that it provides basically a one-way signal system while in the other, with an additional cable, it functions to establish a two-way signal system.
It will be apparent from the foregoing that a very novel arrangement of elements and connecting cables have been provided that are manufactured for easy installation and requires no trained personnel for the installation. The parts including the units 5, 7 and 42 will be manufactured and sold as fixed units and the individual will purchase the cable in accordance with the distance between the remote points. The use of the male and female plugs further prevent any chance of the device being incorrectly assembled and the units 5, with the built-in transformer and buzzer only require that the prongs be inserted into a convenient wall receptacle and the cable plugs connected thereto. The arrangement is believed to be novel and greatly facilitates the installation of either a one-way or a two-way signal system at a minimum cost. The several elements, such as the transformer and the signal devices 9 and 48 may also be of conventional construction and the use of the fastening screw through the tongue 17 will be optional with the user. The parts are few and simple, are strong, durable and require no attachments.
It is to be understood that the invention is not limited to the precise construction shown, but that changes are contemplated as readily fall within the spirit of the invention as shall be determined by the scope of the subjoined claim.
Having described my invention, what I claim as new and desire to secure by Letters Patent is:
A signalling system of the character described that comprises a main unit composed of a housing having therein a step-down transformer and an audible signal device, prongs connected to the high voltage side of the transformer and that projects through a rear wall of the housing for pronged engagement into a wall receptacle that constitutes the source of high voltage electrical energy, the said housing provided with two sets of three female plugs, a central plug of each group of female plugs being connected to the low voltage side of the transformer, a conductor connecting the two next adjacent female plugs of each group, a conductor leading from the low voltage side of the transformer to the signal device, a conductor leading from the opposite side of the signal device to an outer-most female conductor of one group, a pair of remote control devices that include each a housing, a circuit closing switch in each housing, means projected above the housings for actuating the switches, one remote control device also including an audible signal device, the last named control device being provided with three projecting prongs, the central prong being connected to one side of the adjacent switch device and to one side of the last named signal device, the said last named switch device being connected to one outer-most prong and the other outermost prong being connected to the last named signal device, the other said control devices being provided with three projecting prongs, one outer-most prong and a central prong being connected to an adjacent switch device, the other said prongs being a blank lead, a pair of cable devices and with each cable having a length to extend between the main unit and the remote control devices, each of the cables embodying three conductors,
each of the cables at one end being provided with a three-pronged plug and at its opposite end with a plug having three female sockets, the said pronged plugs having pronged engagement into the female sockets of the main unit and the female sockets of each cable having engagement with the respective prongs of each control device, the first named control device establishing a flow of electricity through the signal device of the main unit when the switch is closed, the second named control device establishing a flow of electricity from the transformer to the signal device of the first named control unit.
References Cited in the file of this patent UNITED STATES PATENTS 1,546,148 Smallwood July 14, 1925 2,580,539 Goodwin Jan. 1, 1952 2,648,043 Grogl Aug. 4, 1953 FOREIGN PATENTS 330,797 Italy Oct. 24, 1935 743,499 Great Britain Jan. 18, 1956 OTHER REFERENCES Electrical World, Jan. 15, 1949 (p. 65 relied upon).
US758377A 1958-09-02 1958-09-02 Electric signalling system Expired - Lifetime US2976524A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US758377A US2976524A (en) 1958-09-02 1958-09-02 Electric signalling system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US758377A US2976524A (en) 1958-09-02 1958-09-02 Electric signalling system

Publications (1)

Publication Number Publication Date
US2976524A true US2976524A (en) 1961-03-21

Family

ID=25051512

Family Applications (1)

Application Number Title Priority Date Filing Date
US758377A Expired - Lifetime US2976524A (en) 1958-09-02 1958-09-02 Electric signalling system

Country Status (1)

Country Link
US (1) US2976524A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4228426A (en) * 1978-09-29 1980-10-14 Roberts William A Hospital bed monitor
US4955822A (en) * 1990-01-08 1990-09-11 Look Robert O Two way extension cord
US5135407A (en) * 1991-01-23 1992-08-04 Progressive Technology In Lighting, Inc. Lamp conversion kit
US5234360A (en) * 1992-06-25 1993-08-10 Robert V. Smith Multiple outlet extension cord
US6611783B2 (en) 2000-01-07 2003-08-26 Nocwatch, Inc. Attitude indicator and activity monitoring device

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1546148A (en) * 1922-12-26 1925-07-14 Grover F Smallwood Multiple-outlet socket
US2580539A (en) * 1947-09-30 1952-01-01 Carl L Goodwin Electrical remote-control system
US2648043A (en) * 1950-04-20 1953-08-04 Max F Grogl Patient controlled electric motor for dental units
GB743499A (en) * 1953-04-22 1956-01-18 James Robert William Murland Improvements relating to electrical control systems suitable for use in hospital wards

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1546148A (en) * 1922-12-26 1925-07-14 Grover F Smallwood Multiple-outlet socket
US2580539A (en) * 1947-09-30 1952-01-01 Carl L Goodwin Electrical remote-control system
US2648043A (en) * 1950-04-20 1953-08-04 Max F Grogl Patient controlled electric motor for dental units
GB743499A (en) * 1953-04-22 1956-01-18 James Robert William Murland Improvements relating to electrical control systems suitable for use in hospital wards

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4228426A (en) * 1978-09-29 1980-10-14 Roberts William A Hospital bed monitor
US4955822A (en) * 1990-01-08 1990-09-11 Look Robert O Two way extension cord
US5135407A (en) * 1991-01-23 1992-08-04 Progressive Technology In Lighting, Inc. Lamp conversion kit
US5234360A (en) * 1992-06-25 1993-08-10 Robert V. Smith Multiple outlet extension cord
US6611783B2 (en) 2000-01-07 2003-08-26 Nocwatch, Inc. Attitude indicator and activity monitoring device

Similar Documents

Publication Publication Date Title
US3025486A (en) Three way electric plug
US5095182A (en) Shockproof safety outlet
US4616285A (en) Safety and selective use switch for a power outlet
US3775727A (en) Electrical adapter for converting two-hole receptacle into three-hole receptacle with equipment ground
US6169340B1 (en) Electrical junction box for auxiliary power
CA2224355A1 (en) Electrical testing device
GB1574919A (en) Electric power connection arrangement incorporating a touch-sensitive switch
US3596019A (en) Safety plug and outlet
US3509356A (en) Selective circuit connector
US3928737A (en) Remote control switching device
US4047787A (en) Extension cords for plug-in telephones
US2976524A (en) Electric signalling system
US5998964A (en) Portable appliance charging system
KR100733492B1 (en) An outlet with switches
US2401948A (en) Concealed wiring block
US3167690A (en) Means for preventing the unauthorized use of electricity through a meter
US4019797A (en) System including household connector plug for split wire receptacle
US2454024A (en) Combination electric receptacle and fuse
US3513261A (en) Telephone connector
US20100015819A1 (en) Power Supply Connection Apparatus
CA2255448A1 (en) Optional plug connector for a transfer switch having a terminal compartment
ES262983U (en) Adapter with ground fault interrupter.
UST961003I4 (en) Female connector
US2634409A (en) Electric signaling device
CA2152229A1 (en) Device forming a plug-in base for an electrical relay