US2896050A

US2896050A - Remote-operated fuse

Info

Publication number: US2896050A
Application number: US652495A
Authority: US
Inventors: Henry R Tomlinson
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-04-12
Filing date: 1957-04-12
Publication date: 1959-07-21
Anticipated expiration: 1976-07-21

Description

July 21, 1959 H. R. 'roMLlNsoN REMOTE-OPERATED FUSE Filed April 12, 1957 mvENToR HENRY RTOMLINSQN @wfg ATTORNEY United States Patent Q 2,896,0s RMOTEOPRATED FUSE Henry ER. Tomlinson, Framingham, Mass. Application April 12, 1957, Serial No. 652,495 6 Claims. tcl. 2004413) This' invention relates to a protective device for electric circuits principally in the nature of a fuse and particularly directed to cause operation of the fuse to disrupt the electric circuit by means of a remotely located or extraneous fuse controlling device; the provision of such a fuse whether or not dependency is placed upon the electrical conditions existing in the protected circuit; and the provision of the device as above stated either including a substantially conventional fusible member in the fuse as in the prior art or lacking the same.

A further object and advantage of the invention resides in the provision of means controlling the operation of the fuse to disrupt the flow of electricity in response to an electric pulse or current from a controlling device such as a relay, a high temperature detector, or any other device generally used to initiate interruption of flow of electricity for protection of life or property, wherein the controlling device is remotely located or extraneous with respect to the fuse itself and the fuse itself may or may not be provided with a conventional overload fusible means.

Another object and advantage of the invention resides in the provision of a fuse as above stated which may be operated in timed coordination with other protective equip-mentV in the same electric circuit, and particularly with respect to coordination of a fusible device with the time-current characteristics of other devices so as to increase the efficiency of the electric service by doing away with unnecessary interruptions to flow of electricity; and the provision of a device as above stated for simultaneous operation of two or more fuses in response to an electric current from the controlling device, as for instance in a polyphase system.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings, in which Fig. 1 is a view in elevation of a fuse according to the present invention;

Fig. 2 is a longitudinal sectional view thereof illustrating the device in current-conducting condition;

Fig. 3 is a view similar to Fig. 2 but showing the novel fuse in current interrupting position;

Fig. 4 is a view similar to Fig. 2 but illustrating the conventional fuse disrupted; and

Fig. 5 is a longitudinal sectional view showing a modication.

The present invention has been illustrated as applied to a cartridge type of use, the use of which is well known in the art. This fuse embodies a tube which is a nonconductor and may be made of liber or porcelain. Within tube 10 is a cylindrical liner of ber or other material 11. Provided at the ends of this tube, there are

electricityconducting ferrules

12 and 14 which are adapted to be received in conventional current-carrying clips as is well known in the art. The

ferrules

12 and 14 may be secured to the tube 10 in any desired manner as for instance by screw threads or the like; and the ferrule 12 is provided with an end plug 16 threadedly connected with a cap or the like 18 by which means the plug 16 can be adjusted longitudinally with respect to tube 10.

Attached to the plug 16, there is a helical spring 20 within tube 10, and this is attached to a conducting arcing rod 22. There are exible conductors 24 which electrically connect the arcing rod 22 with the plug 16.

The arcing rod has connected thereto at its opposite end a main fuse element 26 which fuses or melts upon overload to open the circuit, as is well known in the art. As shown in Fig. 2, this fusible element 26 carries a conductor, or conductors, 28 normally held in current-carrying relationshipwith an interior, outwardly-haring, conical surface in ferrule 14. y y

Attached to ferrule 14 by screw-threads or otherwise, there is a retaining cup generally indicated at 30 and this is provided with screened windows 32 to allow for exit of gases'. 4The cu'p is used to confine a retaining plug generally indicated at 34 having shoulder 36 retaining a spring 38. The plug 34 is provided with a beveled end at 40 normally holding the conductor 28 in good electrical contact to the interior conical wall of the ferrule 14 as clearly shown in Fig. 2 and indicated at 42.

The plug 34 is axially bored and accommodates a restraining insulating link 44 which is connected to the fusible element 26. Link 44 is held with relation to plug 34 by means of an auxiliary vfusible element 46 which may be pinned thereto and held by and between a pair of contact screws 48 to which Yare connected leads 50. These leads are connected to apower supply or control circuit by which means Afuse 46 is to be disrupted at the will of the operator or by .some other automatic control means not specifically a part of the present invention.

It will be seen that the conducting arcing rod 22 is restrained from motion due to the force of spring 20 by means of both the main fuse element 26 and the auxiliary fuse element 46. The tensional force of spring 20 seats the retainer plug 34 against the ferrule 14, thus clamping conductor 28 thereto against the action of spring 38. The protected electric circuit is 'made from the bottom clip ferrule, through conductor 28, fuse 26, rod 22, conductors 24, plug 16, cap 18 and ferrule 12.

When current is applied to the auxiliary yfuse 46 by means of a relay or other remote device, not shown, sufiicient current passes throu-gh it to melt the fuse completely and instantly, thus releasing the restraining link 44 allowing spring 38 to move the plug 34 downwardly to the Fig. 3 position. The conductor 28 and the arcing rod are thus released and the spring 20 immediately retracts and pulls the arcing rod 22 upwardly, definitely interrupting the circuit by removing the conductor 28 from ferrule 14. The plug 34 is retained in the cup 30 and the escapement of gases generated by the arc passes through windows 32. The arcing rod travels extremely fast and it breaks contact quickly.

However, the showing of Fig. 4 discloses how the main fuse 26 may be disrupted by the existence of current passing through the fuse suiciently high to cause this fuse to melt. In this instance, the spring 20 causes the arcing rod to move away from the conductor 28 and also of course plug 34 is moved to the same position as in Fig 3. The auxiliary fuse is still intact since no current has passed to cause this fuse to blow. Thus it will be seen that the auxiliary fuse is completely extraneously controlled, but the main fuse operates as in the prior art, without change in its overload protection.

In Fig. 5 there is shown a modification of the inven tion wherein there is no main overload fuse. In this case, the arcing rod 52 is directly connected with a fuse element 54 holding the rod in contact with spring type contacts 56 mounted internally on clip ferrule 58. The

3 other end of the fuse is the same as above described with reference to Figs. 1 to 4.

An insulating plate 60 holds the fuse 54 and a circuit 62 is connected to melt the fuseupon the closing of switch 64 which maybe manual or relay operated, etc. In this case, fusing of element 54 merely releases the arcing rod and it snaps up in the tube 10 as before, interrupting the main circuit instantly.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. A remote operated fuse comprising a fuse body, a pair of spaced members thereon forming electric contacts, a current-carrying movable element to bridge said members, said movable element including a main fusible element, a spring tending to move the element to electrically disconnect said members, means including an auxiliary fusible element to hold the movable element in current-conducting position, a normally open electric circuit connected to the auxiliary fusible element, and means to close the circuit at will to fuse the fusible element and release the movable element.

2. A remote operated fuse comprising a fuse body, a pair of spaced members thereon forming electric contacts, a current-carrying movable element to bridge said members, said movable element including a main fusible element, a spring tending to move the element to electrically disconnect said members, means including an auxiliary fusible element to hold the movable element in current-conducting position, a normally open electric circuit connected to the auxiliary fusible element, and means to close the circuit at will to fuse the fusible element and release the movable element, said main fusible element being disrupted by overload in the current passing through the movable element, and the auxiliary fuse being electrically separated therefrom so that it is unaffected by the disruption of the main fusible element.

3. In a remote operated cartridge fuse of the type described including an insulative cylinder mounting clip, ferrules at the ends thereof with a tension spring associated with one ferrule and a movable arcing rod connected to the spring and tensioning the same in position of the arcing rod to conduct current between the ferrules, that improvement comprising a fusible element connectible with respect to the arcing rod and holding it inoperative current conducting condition, and a separate electric current carrying circuit operatively connected with respect to the fusible element and including a circuit closing device for fusing the fusible element to release the arcing rod for movement to current disruptive con dition, a separate fusible element, the latter being connected between the rst fusible element and the arcing rod and normally carrying the current between the ferrules. I

4. A fuse comprising a hollow body, a ferrule at each end thereof, one ferrule being hollow and having an interior surface flaring outwardly, an arcing rod in the body, resilient means to move the rod in one direction, a conductor secured to the rod, fusible means to hold the rod with the conductor contiguous to the interior surface of the said one ferrule against the action of the resilient means, a retaining member having a surface complementary to the flaring surface, said fusible means being mounted in the retaining member and holding the same yieldingly in position to clamp the conductor against said flaring surface.

5. The fuse of claim 4 wherein the said fusible means is insulated from the ferrules and the arcing rod, and including means to melt the fusible means.

6. The device of claim 1 wherein said last-named means includes a transformer.

References Cited in the file of this patent UNITED STATES PATENTS 1,294,621 Conrad Feb. 18, 1919 1,977,191 Levenstein Oct. 16, 1934 2,087,744 Triplett July 20, 1937 2,315,678 Wallace Apr. 6, 1943 2,481,298 Eldridge Sept. 6, 1949 2,485,076 Timerman Oct. 18, 1949 2,683,201 Miller et al. July 6, 1954 2,757,259 Cruse July 31, 1956 2,762,884 Van Eyk Sept. 11, 1956