US2388783A - Switch assemblage - Google Patents

Description

Nov. 13, 1945. w c FURNAs ET AL 2,388,783

SWITCH AS SEMBLAGE Original Filed Oct. 14, 1940 2 Sheets-Sheet l INVENTORS w 6. W

ATTORNEYS NOV. 13, w, FURNAS ET AL 2,388,783

SWITCH ASSEMBLAGE Original Filed Oct. 14, 1940 2 Sheets-Sheet 2 'weam BY W W A T 7-0 RNEKS Patented Nov. 13, 1945 2,388,783 SWITCH ASSEMBLAGE William C. Furnas and Daniel G. Spotts, Batavia,

111.; said Spotts assignor of his right to William C. Furnas, doing Company,

Original application business as Furnas Electric West Allis, Wis.

Octobcr 14, 1940, serial No.

361,082, now Patent No. 2,296,157, dated Sep tember 15, 1942. August 8,

8 Claims.

The present invention relates in general to improvements in the art of protecting electrical equipment against damage due to overloading, and relates more specifically to various improvements in the construction and operation of thermal overload assemblages for poly-phase electrical systems; and the present application is a division of co-pending application Serial No. 361,082, filed October 14, 1940, Patent No. 2,296,157, granted September 15, 1942.

An object of our invention is to provide an improved thermal overload assemblage which is simple and compact in construction, and which is moreover automatic and highly efiicient in operation.

A more specific object of our present invention is to provide a new and useful thermally actuated overload unit especially adapted for poly-phase electrical systems, and which may be caused to readily and effectively co-operate with reversing mechanism.

Another specific object of the present invention is to provide an improved combined reversing controller and poly-phase overload circuit breaker, which is durable in structure, positive in action and in which normal operating conditions may be rapidly and effectively restored.

A further specific object of this invention is to provide an improved overload circuit interrupting mechanism and improved manually manipulable means for restoring the mechanism to a predetermined condition.

An additional specific object of the invention is to provide a multi-phase thermal overload device, in which overloading of any one of a plurality of lines will quickly actuate a common switch actuating element.

Still another specific object of our invention is to provide an improved combined overload and reversing switch assemblage which is adapted for diverse uses.

Another additional specific object of this invention is to provide an improved poly-phase overload device which can be readily associated with a standard reversing drum controller to produce a compact, durable and relatively simple unit adapted to be manufactured andsold at moderate cost.

These and other specific objects and advantages of our invention will be apparent from the following detailed description.

A clear conception of the several features constituting our present improvement, and of the mode of constructing, assembling and of operating overload'assemblages' built in accordance with Divided and this application 1942, Serial No. 454,134

the invention, may be had by referring to the drawings accompanying and forming a part of this specification in which like reference characters designate the same or similar parts in the various views. v

Fig. 1 is a top view of one of our improved poly phase thermal overload devices, showing the switch contacts thereof in closed position;

Fig. 2 is a transverse section through the ther-L mal overload assemblage, taken along the line 2-2 of Fig. 1;

Fig. 3 is a wiring diagram showing the mode of applying the improved overload device in a system having a reversing and resetting switch therein;

Fig. 4 is a part sectional side elevation of a combined overload and reversing switch assembly; and

Fig. 5 is a transverse section through the revers-' ing and resetting switch, taken along the line 5- 5 of Fig. 4.

While our invention has been shown and described herein as being specifically embodied in a three-phase electrical system comprising one of the improved thermal overload devices having two sets of contacts, and a special rotary reversing switch mechanism associated with the overload device, it is not our desire or intent to thereby uhnecessarily restrict the scope or utility of the improvement. It is also to be understood that while the device has been shown herein in a definite position, the improved assemblage can be placed and operated in any desired position.

Referring especially to Figs. 1 and 2, the improved thermal overload device shown therein comprises in general, a switch assemblage having two sets of fixed contacts [4, I5 secured to an insulated support l6 and co-operating with sets of spring pressed movable contacts ll, 18 carried by guide bars I9, 20 respectively; an insulated main frame or base 2| to which the support I6 i secured, and which is provided with a central longitudinal guideway 22 and hasa pair of in'-' tegrally united insulating blocks 23, 24' secured thereto; a relatively wide elongated bar or slide 25 movable within the guid'eway 22 and having thereon a bracket 26 provided with fingers 21 which are co-operable with the contact guide bars [9, 20; a yoke 21' secured to the switch contact support 16 and providing a reaction plate for a coiled compression spring 28 which coact's with the slidebra'cket' 26; a transverse shaft 29 carried by side plates 30 secured to the insulating block 24, andhavingtubular elements 3 I, 32 respectively normally secured to the shaft by means of spaced respectively, While their opposite corresponding ends are connected to terminal screw 35; a

toothed wheel or ratchet 31 formed integral with j j the element 3| and coacting with a spring pressed pawl 38 carried by the slide 25; and a locally recessed flange 38 formed integral with the other element 32 and coacting with a retaining or rotation preventing reed 48 secured to the other insulating block 23.

The specific details of construction of the thermal overload device constitute the subject of the parent Patent No. 2,296,157, hereinbefore referred to, and the switch contact support l6, main frame base 2|, slide 25, and blocks 23, 24 are preferably formed of moulded insulating material, and the bracket 28 and yoke 27 may be constructed of sheet metal with the aid of punches and dies. The movable contacts l1, l8 are normally urged toward the fixed contacts |4, |5 by means of coil springs 4| so as to complete the circuit through the lines 42, 43 of the electrical system shown in Fig. 3; and these lines 42, 43 together with the line 44 are connectible to a source of electric current such as a motor 45, through a reversing switch or reversing drum controller 46. The improved thermal overload switch comprising th contacts |4, |5, l1, l8 and the support H5, is attachable as a unit to the base 2|, by means of screws 41, and need not necessarily be used in connection with a reversing controller. The contact spaces of the overload switch are segregated from each other by means of an insulating wall 48, and this wall may be additionally secured to the base 2| through the block 23 by means of a screw 41 as shown in Fig, l. The blocks 23, 24 may also be firmly secured to the base 2| by means of fastening screws 41, and all of theattaching screws 41 may be provided with lock washers as shown. The fixed contacts I4, l5 which are nearesteach other, are conductively connected to their respectiveheating coils 34, 35, by means of conductors 49, 58; and the opposite ends of the coils 34, 35 areconnected respectively to the binding posts or terminal screws 38 by means of other conductors 5|, 52, see Figs. 1 and 2.

The elongated bar or slide 25 is freely slidable in the guideway 22 formed in the base 2|, and the fingers 2'! of the bracket 25 which is secured to one end of the slide 25, are movable in direct alinement with the movable contact carrier and guide bars H3, 28. The compression spring 28 00 acts with the bracket 25 and with the yoke 21' betweenthe fingers 21, and constantly tends to move the contacts l8 away from the fixed contacts l4, l5, and to thereby interrupt the lines 42, 43. However, such interruption of the circuits is normally prevented by the shaft 29 and the tubular elements 3|, 32 which are rigidly attached to this shaft 29 by the fusible rings 33 as shown in Fig. 2. As previously indicated, the transverse shaft 29 is journalled in insulating side plates 3|] rigidly attached to the insulating block 24 by means of screws 53, andthe shaft 29 is formed of three alined rigidly interconnected sections of which the central section is made of insulatin material while the opposite end sections are constructed of metal with which the rings 33 will readily unite when cool, and upon which the elements 3|, 32 are snugly fitted. The tubular. elements 3|, 32 are also formed of similar metal, and

are prevented from shifting longitudinally of the shaft 29 when the rings 33 are reduced to a molten or plastic state by the heat generated by one or both of the coils 34, 35, by means of metal clips 54 held in place by the screws 53 and coacting with the ratchet 31 and flange 39 respectively, see Fig. 2. The pawl 38 which normally coacts with the ratchet 37, is supported directly by the slide bar 25, and is normally urged toward the ratchet wheel as shown in Patent No. 2,296,-

157; and the holding reed 40 which constantly fixes the element 32 and its flange 39 against rotation, is secured to the fixed block 23 by means ofa screw or the like. The assemblage is obviously such that when the parts are in the position shown in Fig. 1 and the fusible rings 33 are cold,

the movableswitch contacts l1, l8 will be in closed position; whereas if either coil 34, 35 is heated by overloading of the electrical system sufficiently to melt the rings 33 in either element 3|, 32, the slide 25 will be released and the spring 28 will immediately become effective to shift the slide and bracket 26 so as to simultaneously move both sets of contacts IE to open or circuit interrupting position.

While the improved thermal overload device is adapted to be utilized as a unit disposed in any position, and in conjunction with any single or polyphase electrical system, the device may be advantageously utilized in conjunction with a manually operable reversing switch or reversing drum controller 48 as shown in Figs. 3, 4 and 5. In the assemblage of Figs. 4 and 5, the overload device is fiXedly suspended from the reversing switch frame 58 by means of clamping and attaching screws 59, and the outer end of the movable slide 25 coacts with abutments '60 formed on the swinging end of an arm 6| swingably suspended from the frame 58 by means of a pivot pin 40 62. The reversing controller or switch 46 may be of the general type shown and described in detail in Furnas and Thompson patents, Numbers 2,108,883 and 2,137,481, and comprises in general a spindle 53 journalledfor rotation in the frame 58 and being embraced'by insulating bushings 84; an operating crank or handle 84' secured to one end of the spindle 63; a roller 85 journalled on a crank 68 secured to the opposite end portion ofthe spindle 63, and being adapted to 00- act witha lug 6| formed on the medial portion of the swingable lever arm 8| in order to reset the overload device; three sets of movable contacts 61, '58, 69 carried by the medial portion of the spindle 83; and three sets of relatively fixed contacts 1|), H, 12 carried by side bars 13, 14secured to the frame 58, and being co-operable with the movable contacts 61, 58, 69 respectively. The lever arm BI is constantly urged in one direction so that the lugs 69 thereon maintain contact with the outer end of the slide 25, by meansof-either a leaf or coil spring 15; and the extreme end 11 of this arm 6| coacts with a slot 16 in a reciprocable indicator bar 18 which is slidably mounted in the frame 58. A relatively light coil sprint, 19 coacts with the arm Bland with a bracket carried by the bar 18, and the end of the bar I8 remote from the slot 16 is adapted to be projected externally of the end wall 8| of the frame 58 when the slide 25 is released to open the overload contacts I8. The entire overload and reversing switch mechanism may be housed within a readily removable cover 82 as shown in Figs. 4 and 5.

During normal operation of the improved overload device, the thermal overload devic of Figs. 1

2,388,783 and 12 may be interposed in the'lines' 42, 43, 44,

in the manner shown in the diagram of Fig. 3, and the .slide 25 will normally be set in the position shown in Fig. 1 wherein the circuit through the fixed contacts l4, l5 and through the movable contacts IT, IS will be completed. The heating coils 34, 35 will be located withi the lines 42, 43

respectively and will not become heated unless- -overload conditions prevail in the electric circuit. The slide will be held in the position shown in Fig. 1 by mean of the pawl 38 coacting with the ratchet 31, and the reed 40 will have coaction with the recessed flange 39.

Whe an overload condition is reached in either of the lines 42, 43, the heating coil 34, within the overloaded line will become heated sufficiently to melt the metal films and rings 33 within the corresponding element 3|, 32. If the overloading occurs in the line 42, then the coil 35 will be heated and will release the shaft 29 from within the fixedlypositioned-element 32, thereby permitting the spring 28 to become effective to quickly shift the slide 25 away from the position shown in Fig. 1. The release of the shaft 29 from within the element 32 and the displacement of the slide 25, will cause the pawl 38 to revolve the ratchet 31 and the shaft 29, and will thus permit unrestrained shifting of the slide 25 by the heavy spring 28.

If the heating coil 34 in the line 43 should become heated due to the overloading, the element 3| will be released from the shaft 29 by virtue of the melting of the rings 33 within the element 3 I. This release of the element 3| from the shaft 29, will again permit the slide 25 to shift under the influence of the spring 28, and during such shifting the pawl 38 will rotate the. released element 3| and ratchet 31, thus permitting the slide 25 to move freely. In this case the shaft 29 will be retained in fixed position by the reed 40 coacting with the flange 39, and only the element 3| will be released for rotation.

When the slide 25 moves away from the position shown in Fig. 1, the fingers 2'! of the bracket 26 which is carried by the slide 25, engage the movable contact supporting bars l9, 2!], and quickly open both sets of contacts. The movement of the contacts l7, I8 is simultaneously interrupted whenever overloading of either or both of these lines occurs. LAS soon as the circuit is interrupted, and regardless of which heating coil 34, 35 has been overloaded, the molten metal films and rings 33 will again quickly reunite the shaft 29 and the elements 3| 32. The thermal overload mechanism will then be automatically restored preparatory to resetting of the slide 25. Such resetting or return of the slide 25 may be readily accomplished by merely pushing against the projecting end of the slide 25 until the latch 38 re-engages the ratchet 37. As the fingers 21 are withdrawn from the ends of the bars 20, the springs 4| will become quickly effective to move the contacts l1, l8 into engagement with the contacts l4, l5, thereby re-establishing the circuit through the lines 42, 43 and returnin the system to normal operating conditions.

The return of the overload device to normal operating conditions may be readily effected with mechanism such as shown in Figs. 4 and 5, which mechanism operates in the following manner. When overloading of a line 42, 43 occurs, the slide 25 will be urged upwardly from the position shown in Fig, 4 and will move the lever arm 6| upwardly. This upward swinging motion of the lever 6| is possible because the handle 64' and the roller '65'will have been moved out of central position when the circuit is closed, for either forward or reverse operation, thus permitting the lug 6| to move upwardly without'obstruction. The up- Ward swinging motion of the lever 5| will simultaneously move the signal bar 8| upwardly to indicate that the overload device has operated, and after the overload device has interrupted the circuit, the handle 64 must be returned to central or off position as shown in solid lines in Fig. '5, in order to cause the roller 65 to. coact with the lever 6| and reset the overload mechanism. When the roller 65 is thus returned to central position, it engages the lu 6| and swings the lever 6| downwardly to positively return the slide 25 to normal position. After the overload device ha been thus reset, the handle 64' .ulated in the desired direction to operate the reversing switch 46 without affecting the overload switch contacts. In this manner the overload device may be utilized in conjunction with a drum controller or other reversing switch 46 and a signal, and the assemblage may be quickly reset for normal operation.

From the foregoing detailed description it will 7 be apparent that our present invention provides an extremely simple, compact, and highly efficient thermal overload device which may be utilized either for single or poly-phase electric circuits. The device is especially useful in polyphase systems because it insures simultaneous interruption of at least two lines of the system. The circuit through all of the lines may be .quickly and simultaneously re-established without replacing fuses or other parts, and by merely restoring the slide 25 to inactive position since the thermal overload devices are self-restoring. All portions of the improved overload device are sturdily constructed and are effectivelyinsulated wherever necessary, and the overload unit obviously occupies relatively small space and may therefore be utilized for diverse purposes. The combined assemblage of reversing switch and thermal overload device is especially useful under many conditions, and the overload device may obviously be readily combined with most standard reversing switches or controllers. The improved overload assemblage can also be manufactured and sold at moderate cost, and has proven highly satisfactory in actual commercial use. The switch assemblage which is utilized in the overload unit is also so constructed that it can be used in various types of switch assemblages as well as in the overload unit, and this switch assemblage has also proven highly satisfactory in actual use.

It should be understood that it is not desired to limit this invention to the exact details of construction or to the precise mode of operation, herein shown and described, for various modifications within the scope of the claims may occur to persons skilled in the art.

We claim:

1. In combination, an overload switch having contacts for completing electric circuits through independent lines, a slide for simultaneously opening all of said contacts under overload conditions in any of said lines, a reversing switch for effecting opening and closing of said circuits independently of said contacts, manually operable means associated with said reversing switch for resetting said slide to close said contacts when said reversing switch is opened, and means operable by said slide for indicating when said circuits have been interrupted.

can be manipable by said roller when said reversing switch is opened for moving said slide to restore said overload switch contacts to closed position.

3. In combination, an overload switch having contacts for completing electric circuits through independent lines, a slide for simultaneously opening all of said contacts under overload conditions in any of said lines, a reversing switch for efiecting opening and closing of said circuits independently of said contacts, a cam roller carried by said reversing switch, and a lever coacting with said roller when said reversing switch is opened to place said overload switch slide and contacts in closed position.

4. In combination, a frame, an overload switch mounted on said frame and having contacts for completing electric circuits through several lines, a slide for simultaneously opening all of said contacts under overload conditions in any of said lines, a reversing switch also carried by said frame for effecting opening and closing of said circuits independently of said overload switch, a cam roller operable by said reversing switch, and a lever coacting with said roller when said reversing switch is opened for moving said slide to restore said overload switch to closed position.

5. In combination, a frame, an overload switch l carried by said frame and having contacts for completing electric circuits through several lines, a slide for simultaneously opening all of said contacts under overload conditions in said lines, a rotary reversing switch also carried by said frame for effecting opening and closing of said circuits independently of said overload switch, a cam roller revolvable about the axis of rotation of said reversing switch when the latter is actuated, and a lever pivotally suspended from said frame and coacting with said roller when said reversing switch is opened to move said slide and close said overload switch.

6. In combination, a set of overload contacts for completing electric circuits through independent lines, a slide for simultaneously opening all contacts of said set under overload conditions in said lines, a contact carrying rotor revolvable about an axis disposed parallel to the direction of movement of said slide and being manipulable to open and close said circuits independently of said overload contacts, and means operable when said rotor is moved into circuit opening position for resetting said slide to close the overload contacts.

'7. In combination, a set of overload contacts for completing electric circuits through several lines, a slide automatically movable to open all of said contacts under overload conditions in any of said lines, a contact carrying rotor revolvable in opposite directions about an axis to open and close said circuits independently of said overload contacts, and mechanical means interposed between said rotor and slide and being operable when said rotor is swung into circuit opening position to reset said slide so as to close the overload contacts.

8. In combination, a set of overload contacts for completing an electric circuit, a slide automatically movable to open said contacts under overload conditions, a contact carrying rotor revolvable to open and close said circuit independently of said overload contacts, and mechanical means -interposed between said rotor and slide and being operable when said rotor is moved into circuit opening position to reset said slide so as to close the overload contacts.

WILLIAM C. FURNAS. DANIEL G. SPOITS.

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