US 3840717 A
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Description (OCR text may contain errors)
United States Patent. [191 Pekrul et al.
[451 Oct. 8, 1974 1 MANUALLY OPERATED ROTARY SWITCH AND COMBINATION LOAD CONTACT-FUSE CLIP THEREFOR  Inventors: Ronald G. Pekrul, Southington;
' Louis T. Stegmaier, Plainville, both of Conn.
 Assignee: General Electric Company, New
' York, NY.
 Filed: Aug. 20, 1973  Appl. No; 389,979
 U.S. C1 200/284, 317/114, 200/5 R, 200/15, ZOO/51.04, 337/9, 339/252 F  Int. Cl. H0111 9/10, H02b H18  Field of Search 317/114; 339/252 F, 253 F, 339/256 C, 258 F, 259 F, 262 F; 200/5 R, 11 R, l4, 15, 155 R, 166 E, 166 BH, 5 R, 51.04, 170 A, 275, 274; 337/9, 190, 208, 209, 213, 215
 References Cited UNITED STATES PATENTS 1,040,331 10/1912 Horton 339/253 F 2,199,793 5/1940 Hammerly 339/253 F 2,767,283 10/1956 Jung 339/252 F 2,924,809 2/1960 Wilson 339/258 F 3,114,024 12/1963 Tillson 200/293 3,188,404 6/1965 Fichter 200/14 3,705,374 12/1972 Stanb'ack 200/166 E 3,778,566 Gusaras 200/14 Primary Examiner-Robert K. Schaefer Assistant Examiner-Gerald P. Tolin Attorney, Agent, or Firm-R. A. Cahill; P. L. Schlamp; F. L. Neuhauser ABSTRACT A low profile heavy duty manually operated double break electrical switch having a molded insulated housing with interior walls dividing the interior of the housing into isolatedswitching chambers for the different phases to be switched. A rotor journalled by the housing mounts a plurality of switching blades which respectively engage separate line and load contacts.
naefiram'eaniaermainred t ro' rfiastripoi metaland' is supported by 'a separate support member, which spans a switching chamber and is secured to the dividing walls of the switching chamber to mount the load contact in depending relation at a midpoint of the load contact in depending relation at a midpoint of the support to provide resiliency and minimize mechanical stresses imposed on the housing and enhance the accuracy of alignment. The load contact includes a fuse clip portion positioned below the support at the same level as the switch contact portion to minimize the housing profile and the support is notched to expose thefuse clip portion for the vertical insertion of the blade of a cartridge fuse. The fuse clip portion is bifurcated and reinforced by springs which span the closed end thereof. Variant load contact designs not requiring housing modifications for mounting are disclosed.
9 Claims, 6 Drawing Figures MANUALLY OPERATED ROTARY SWITCH AND COMBINATION LOAD CONTACT-FUSE CLIP THEREFOR This invention relates generally to electric switches of heavy duty ratings and is particularly applicable to manually operated rotary switches having low profile housings and to a new and improved combination load contactfuse clip unit which is economical to manufacture and is suited for use in such switches having a wide range of ratings and variations.
v Manually operated fused enclosed electric switches having ratings ofthe order of up to 100 a., 240 v. or more have heretofore commonly employed a handle operated rotary switch in series with a fuse in each of the phases of the protected electrical circuit. Typically, the load contact in such a switch is selectively engaged and disengaged by a movable blade of the rotary switch for closing and opening the switch and is cantilever supported in spaced parallel relation with the movable blade by an upstanding interior wall of the molded insulated housing of the switch. The fuse clip for receiving one end of the associated fuse for such a load contact has commonly been positioned above the load contact to project in the opposite direction from the load contact and has been clamped to the load contact by suitable fasteners. Since the area of effective contact between the load contact and the fuse clip does not extend to the full'cross-section of the joint therebetween, heat was generated by the heavy I currents passing through the joint. Moreoventhe projection of the load contact and the fuse clip in opposite directions has required a housing sufficiently deep to accommodate combined heights of these assembled parts. I
It is an object of the present invention to provide a unique load contact-fuse clip unit which is economical to manufacture and is-efficient and durable in use.
Another object of this invention is to provide a new and improved combination load contact-fuse clip which can be fabricated by simple bending and punching operations and which minimizes the quantity of copperrequired therefor.
A further object of this invention is to provide a new and improved combination load contact-fuse clip unit which is provided with an improved alignment and support arrangement.
Still another object of this invention is to provide a fused manually operated rotary switch incorporating a combination fuse clip-load contact unit which accommodates a lowprofile switch housing.
. Still anotherobject of this inventionis to provide a manually operated double break rotary switch having a combination load contact-fuse clip unit mechanically supported in the switch housing by a support member which spans the unit for improved mechanical support and alignment accuracy.
Other'objects will be in part obvious and in part pointed out more in detail hereinafter.
A better understanding of the invention will be obtainedfrom the following detailed description and the accompanying drawing of an illustrative application of the invention.
In the drawings: j
FIG. 1 is a side view, partly broken away, of a fused manually operated double break rotary switch incorporating'the present invention;
FIG. 2 is a framentary top view of the switch mechanism of FIG. 1;
FIG. 3 is across-sectional view taken along the lines 33 of FIG. 1;
FIG. 4 is a side view of the load contact-fuse clip of the present invention;
FIG. 5 is an end view of a variant form of the combination load contact fuse clip unit of the present invention, and
FIG. 6 illustrates another variation of the present invention.
To describe the invention in further detail, there is shown in FIG. 1, a heavy duty fused manually operated double break rotary electrical switch which is housed in an insulating enclosure 10 which journals a rotor 12 in the end wall thereof. The rotor 12 is, provided'with a square extension 13 through one of the end walls for connection to a handle, not shown, for the manual operation of the rotor.
The rotor 12 mounts a plurality of switches 14 having switch blades 15 for rotation therewith. As shown,
switch blades 15 comprise a pair of parallel blades l6, l8 engageable with the load and line contacts 20, 22 (FIG. 3) to form a double break switching arrangement for opening and closing the switch. I
The switch 14 of only one of the phases of the protected line is fully illustrated. However, identical switches such as switch l4a, are positioned axially along the rotor 12 for each phase of the protected circuit.
Associated with each of the contacts 20, 22 are arc enclosures 26, 28, respectively, which serve to shield the arc generated between the blades of the switch 14 and the contacts 20, 22, respectively, as the switch is being opened, it being understood that the flexure of the blades 1 6', l8 against the bias of springs 17 causes the blades to resiliently grip the contacts 20,22 when the switch is closed. A fuse (shown in phantom) having a blade 30 is shown as being connected in series with the rotary switch 14. The blade 30 of the fuse is resiliently received in the receiving slot 36 of the spaced parallel upstanding legs 32, 34 as best shown in FIG. I.
As shown in FIG. 4, the leg 34 is bifurcated so that each of the bifurcated portions 34a, 34b is resiliently biased into engagement with the blade 30 of the fuse independently of the other. This coupled with the upset dimples 70 assure contact between the blade. 30 and the fuse clip despite anymisalignment of the blade 30 and the receiving slot 36 of the fuse clip. Projections 38 retain the fuse blade within the slot under short circuit conditions. It will be noted that each of the bifurcated portions 34a, 34b of the leg 34 are directly backed by the leg 32 of the fuse clip so. that the blade 30 is clamped directly therebetween. Flat reinforcing springs 35 span the closed end of the fuse clip and projections 40 of the spring are received in notches 42 provided in backing leg 32 to fix each reinforcing spring 35 in assembled position to reinforceand bias each of the bifurcations 34a, 34b toward the backing wall provided by leg 32. The springs 35 are formed of a spring steel having a high yield strength and elongation to reinforce and bias the legs 32, 34 of the fuse clip into good electrical contact with the fuse blade 30 throughout the life of the switch despite any fatigue which may take place in the copper forming the fuse clip during use.
As will be apparent from the drawings, the combination fuse clip load contact is formed from a unitary strip of copper by being bent into a generally S-shape configuration by a simple bending operation and the shape and upset portions of the combination unit may be produced in a simple punch press operation. As a result, a load contact fuse clip construction formed from a single piece of stock having the maximum current carrying capacity can be produced economically.
Referring particularly to FIGS. 1 and 2, the combination load contact-fuse clip unit is provided with a support member 44 which is formed separately therefrom and is connected to the combination load contact-fuse clip by fastening screws 46 engaging horizontal wall 45 formed intermediate the fuse clip and load contact portions thereof. The support member 44 spans, or extends laterally beyond the load contact and fuse clip in both directions and is secured by fasteners 48, 50, re-
spectively, to upstanding walls 54, 56 which define a switching chamber isolated from like switching chambers for the switches of the other phases. Not only does this construction provide high accuracy of alignment of the load contact and fuse clip with the housing and the rotor blades of rotor 14, due to the distance between the points of support provided by the screws 48 and 50, but also this construction causes less mechanical stresses to be imposed on the housing as a result of the sudden opening of the switch or the replacement of the fuse. As best shown in FIG. 2, a corner of support member is cut away at 52 to expose the receiving slot 36 between the legs of the fuse clip to accommodate the downward insertion of the blade 30 of a cartridge fuse. A pair of apertures in the support member receive the upstanding locators 53 molded in the enclosure for additional alignment accuracy.
As shown in FIG. 1, the fuse clip and load contact are disposed on one side of support member 44 and at the same horizontal level so. that the housing may have a low profile as compared with a heretofore commonly used design in which the fuse clip was disposed directly above the load contact.
Since in the design of the present invention, the wall 58 which serves the function of isolating the are produced by opening the switch for one phase from the switch for an adjacent phase by contributing to the minimum required surface and air distance between the arcs produced by adjacent switches and is not required to withstand the mechanical stresses which would be imposed on a fuse clip-load contact cantilever mounted thereon, it may be narrow, thereby minimizing the axial length of the housing which would otherwise be required.
In the variant of FIG. 5, a separate adapter or insert 60 is shown as being inserted in the slot 36 of the fuse clip in order to accommodate the blade 61 of a fuse of a lower rating so that a single load contact-fuse clip component can be utilized for a wide range of current ratings. The adapter 60 has an apertured horizontal wall 62 and a depending wall 64 positioned in blade receiving slot 36 and provides a formed projection 65 to position the fuse blade in the slot 36 and is secured in position by screws 46. i I
The variant illustrated in FIG. 6 is illustrative of a' modified form of the invention wherein the rotor 14 comprises a single blade rotor 14a and the load contact is formed of a pair of spaced parallel legs 20, a for receiving the single blade 14a therebetween. The modified load contact of this variant is supported by the support member 44 in the same manner as with the other design so that no modifications of the housing or change in the assembly of the load contact in the housing is required.
FIG. 6 also illustrates another variant of the design wherein a fuse is not used in the switch. A terminal 66 is connected directly to the load contact by a stud 68 and the fuse clip portion is eliminated.
From the foregoing, it is apparent that this invention provides an improved adaptable, high performance, combination load contact-fuse clip unit suited for use in a wide range of switch ratings and variants wherein the housing may have a low profile and does not need to be modified for the several variants. It is further apparent that the forces imparted to the housing by the support of the combination load contact-fuse clip unit are significantly reduced from designs heretofore used and do not involve any cantilever mounting thereof.
As will be apparent to persons skilled in the art, various modifications, adaptations and variations of the foregoing specific disclosure can be made without departing from the teachings of the present invention.
1. A low profile, heavy duty rotary switch comprising an insulated housing having interior walls dividing the interior of the housing into a plurality of switching chambers for isolating the contacts of the circuits of different phases to be controlled by the switch from each other, a rotor journalled by said housing and mounting a plurality of switching blade means for rotation therewith, said switching blade means being axially spaced along said rotor with each of said switching blade means being positioned in one of said switching chambers, a load contact positioned in each of said switching chambers to cooperate with: an associated switching blade means for opening and closing one of the circuits, a support for each said load contact, each said support spanning each respective switching chamber and mounted by the walls on each side of the chambers, said load contacts extending downwardly from said supports between said walls and parallel to the plane of rotation of each said switching blade means, and means securing each said load contact to each said support intermediate the ends of said supports.
. 2. A switch as recited in claim 1 wherein each said load contact is formed from a strip of metal and is of a generally S-shaped configuration to provide a fuse clip portion having a pair of spaced legs generally disposed below each said support for gripping the blade of a cartridge fuse therebetween.
3. The switch defined in claim 2 wherein the means for securing each load contact to each support is disposed intermediate the fuse clip and load contact portions thereof.
4. The switch defined in claim 2 wherein each support is notched to expose the fuse clip portion to accommodate the downward insertion of the blade of a cartridge fuse.
5. The switch defined in claim 2 wherein one leg of each fuse clip portion is bifurcated so that each bifurcated portion thereof independently biases the blade of a cartridge fuse directly against the backing wall provided by the other leg of each fuse clip portion.
6. The switch recited in claim 5 wherein a U-shaped reinforcing spring spans the closed end of each bifur- 6 of each said switching blade means, and line contacts engageable with the other end of each said switching blade means are provided to form a plurality of double break switches.
9. The switch recited in claim 1 wherein a cable con nector is mounted by each said load contact.