US1236520A - Electric switch. - Google Patents

Description

H. E. WHHE.

ELECTRIC SWITCH.

APPLICATION mu) JAN.22. 1914 3 SHEETSSHEET I.

Patented Aug. 14, 1917.

ATTORNEY Harald [.Whita. INVENTOB WITNESSES. QM. Q. QM

H. E. WHITE.

ELECTRIC SWITCH.

APPLICATION FILED IAN. 22, 1914. 1,236,520. Patented Aug. 14,1917.

I I 3 SHEETS-SHEET o FF ATTORNEY H. 1E. WHITE. ELECTRIC SWiTCH.

APPLICATION FILED JAN. 22. 1914. 1,236,520. Patented Aug. 14,1917.

3 SHEETS-SHEET 3.

.WITNESSE LAM. a. QM

ATTORNEY F15 5 HnruHLWHTaJNvI-imm UNITED STATES PATENT OFFICE.

HAROLD E. WHITE, 01? GLEN RIDGE, NEW JERSEY, ASSIGNOR TO CROCKER-WHEELER COMPANY, OF AMPERE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

ELECTRIC SWITCH.

Specification of Letters Patent.

Patented Aug. 14, 1917.

Application filed January 22, 1914. Serial No. 813,622.

To all whom it may concern:

Be it known that I, HAROLD E. WHITE, a citizen of the United States, residing at Glen Ridge, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Electric Switches, of which the following is a specification.

My invention relates to electric switches in general, but more particularly to those employed to open and close or control the circuits and connections of electric motors or other electrical machinery or apparatus. The object of my invention is to make such switches reliable and convenient in their action. To this end my invention consists of certain forms and arrangements of the elec trical contact making parts and connections as well as of the mechanical parts. These mechanical parts or means employed to operate my switches are shown and described, for the sake of completeness, but are not claimed herein because they are made the subject matter of my divisional application having the same title and original date of filing as the present application.

The accompanying drawings illustrate the construction and operation of typical examples of my switches. Figures 1, 2 and 3 are perspective views of an elementary form of switch embodying some of the features of my invention. The electrical connections of the switch shown in Figs. 1, 2 and 3 are diagrammatically represented in Fig. 1. Figs. 5 and 6 show the side motion or sliding of the contacts which may be obtained by my construction. Fig. 7 is a section and Fig. 8 a plan view showing some of the mechanical features of my switches. Fig. 9 is a section of a form of my switch.

The particular purpose of the simple form of my switch shown in Figs. 1, 2 and 3 is to start, stop and reverse the direction of rotation of a three-phase motor by controlling the connection of its three terminals to the three supply lines.

The corresponding electrical connections are indicated diagrammatically in Fig. 4. In Fig. 1 the switch is represented in its off position, that is, the electrical connections are broken. My switch in this case comprises the stationary elements 1, 2 which may be a board of wood or other suitable material provided with electrical contact making parts 3, 4 5, 6, 7 and 8. These contacts may be pieces of copper or other conducting material fixed in or upon board 1, 2. The movable element 9, 10 may also be a board of wood or other suitable material mounted on the rod 11, which is carried by the crank 14 that is attached to the rotatable shaft 15 operated by the handle 16. The movable element 9, 10 carries electrical contact making parts 17, 18, 19 and 20 which may consist of cylindrical studs of copper or other material. Preferably the construction is such that these studs are movable in and out of the board a little distance and tend to be forced toward the stationary element 1, 2 by spring pressure. This pressure may be conveniently obtained from helical springs 21 and 22 shown in Figs. 5 and 6 surrounding portions of the studs of reduced diameter. In the position represented in Fig. 1 the movable element 9, 10 is at its maximum distance from the stationary element 1, 2 and the contact making parts of the former are sufficiently separated from those of the latter to break effectively any electrical connection between the two sets. The movable element 9, 10 is guided by the swinging arm 12, 13 so that it remains parallel to the stationary element 1, 2 as it is moved from side to side by the handle 16 and crank 1 1.

In Fig. 2 the movable element 9, 10 is represented as thrown to the right in which position its contacts 17, 18, 19 and 20 are pressed against the contacts 4:, 5, 7 and 8 respectively, of the stationary element, thereby establishing electrical connection between the two sets. Moreover these electrical connections are most effective because there is a certain amount of sliding motion between each movable contact and the corresponding stationary contact. This sliding motion is due to the side swing of the element 9, 10 and occurs while the moving contacts are being forced a little distance against the spring pressure described. The cause of this sliding motion is shown by comparing Figs. 5 and 6. In Fig. 5 the contacts 17 and 18 carried by the element 9, 10 are just beginning to touch those on the stationary element 1, 2. The further movement of the element 9, 10 into the position indicated in Fig. 6 has the efiect of sliding the faces of the contact studs 17 and 18 on the contacts 4: and 5 respectively, at the same time forcing the studs in and compressing the helical springs 21 and 22 as represented. One of the advantages that is obtained by the arrangement of the parts in this particular form of my switch is the fact that the contact surfaces are vertical. Hence any dirt or any particles of metal due to wear or fusion will fall away freely from both of said surfaces so that they can be brought together to make a good electrical connection. With horizontal contact sur faces, such extraneous matter tends to remain and collect on the lower one which prevents or interferes with the making of a proper electrical connection. If the board 9, 10 is thrown to the left by means of the handle 16 the connections of two of the supply lines B and C with the motor terminals E and F are reversed. This, of course, causes the motor to run in the opposite direction. The electrical connections are shown in Fig. 4, the circles 3, 4, 5, 6, 7, and 8 representing the contacts on the fixed element 1, 2, and the squares 17, 18, 19 and 20 representing the contacts on the movable element 9, 10. In this particular case the contacts 17 and 18 are connected together by a conductor 23, and the contacts 19 and 20 are connected by a conductor 24.

Some of the mechanical features of my switch shown in section in Fig. 7 and in plan in Fig. 8 are applicable to those uses for which it is desirable to insure the movement of the switch in one direction from a neutral position before it is in condition to be moved in the other direction. For example, in controlling an induction motor it is important to make sure that the movable contacts are thrown to the right in order to connect the primary windings in star relation for start ing before these contacts are thrown to the left to make the delta connections for running. In Fig. 8 the neutral or off position of the switch handle 26 is shown in solid lines, the electrical connections being open. To start the motor the handle 26 mounted loosely on the shaft 27 is moved to the right into the position indicated in dotted lines and marked start. This movement of the handle 26 to the right carries the arm 28 rigidly mounted upon the shaft 27 to the left, because the other end 29 of the handle lever engages with the lug 30 on the said arm 28. The movable contacts of the switch are controlled by the shaft 27 in Fig. 8 which corresponds to the shaft 15 in Fig. 2 in its mechanical function. The motor windings are thus connected in star fashion for starting. At the same time the pin 31 movable in the arm 28 is lifted by the inclined plane 32 shown in Fig. 7, so that its upper end projects above the surface of the arm 28. As soon as the motor has reached a proper speed, the switch handle 26 is thrown to the left into the run position indicated in Fig. 8. If this: movement is made with a fair degree of rapidity, the lever 29 catches the projecting end of the pin 31, and the arm 28 is thereby carried to the right. This rotates the shaft 27 which controls the movable contacts and causes them to make the delta connections for running the motor at full voltage. The pin 31 may be caught by the lever 29 simply because the former does not have time to drop out of the way. It may also be temporarily prevented from dropping by the strip of metal 33 which drips it while the arm 28 is swinging, by reason of the centrifugal force of the mass 34 attached to the strip 33. Either or both of these means may be employed to catch the pin 31 in order to carry the arm 28 to the right.

In many cases it is desirable to combine my switch with the top or cover of a case or vessel containing oil which serves to suppress the sparking and arcing that tend to occur on opening electrical connections. In Fig. 10 which is a section of such an arrangement of my switch, most of the mechanical parts are contained in the upper cover 41, 42. This sets on another cover 43, 44 which is hinged at 47 on the case 45, 46 containing oil. The electrical parts are attached to the hinged cover 43, 44, and are readily accessible by lifting it. At the same time these electrical contacts and connections are immersed in the oil when the cover 43, 44 is lowered into place. The board 9, 10 in Fig. 10 corresponds to the board 9, 10 in Fig. l and is moved by the handle 16 to open and close the electrical connections controlled by the switch. In the construction shown in Figs. 1 and 10 this movable part 9, 1O simply acts to connect together the contacts on the board 1, 2 of Figs. 1 and 10 and has no external electrical connections so that it is entirely free to move. The connections to the board 1, 2 are made by flexible conductors 48 to enable it to swing upward when the cover 43, 44 is raised. This arrangement of the mechanical and electrical parts gives ready access to them, at the same time they are fully inclosed for protection and may be conveniently immersed in oil or lifted therefrom without disconnecting or disturbing them.

I have shown and described certain forms and uses of my switches which illustrate their construction, operation and application, but my invention is not confined to these particular cases. Other mechanical means may be utilized to move and control the contact-making parts so as to effect the proper electrical connections without departing from my invention. For some purposes only one or a few of its features may be included. If desired my switches may be constructed to operate without involving the sliding of the contact surfaces upon each other, which is herein described as an ad.-

vantageous but not essential feature of my invention. It is evident that the stationary element and not the movable element may be constructed with contact-making parts that yield to pressure, or both may be so constructed. It is also evident that the movable element may be provided with electrical connections in the form of flexible or sliding conductors.

With the particular electrical connections illustrated in the drawings, some of the contact-making parts serve in two different positions of the switch. For example in Fig. 4: the stationary contacts 4 and 7 are connected to the movable contacts 17 and 19' for running the motor in one direction and to the movable contacts 18 and 20 for running it in the other direction. It would be possible to have four stationary contacts for one switch position and four diflerent contacts for the other position, making eight in all.' The arrangement which I have shown permits two contacts to be used for both switch positions, so that only six instead of eight stationary contacts are required. Thus a very considerable gain in simplicity, compactness and cost is made. In other words, three sets of contact-making parts are illustrated in Fig. 4. One of these sets may be brought into electrical connection with either of the other two sets, cor responding to two different switch positions. Each of the three sets may have its own distinct contacts, or some of the contacts may be common to two sets, as in Fig. at. In Fig. 4 all of the contacts of the movable set are used in both operative switch positions. In this way various combinations or grou ings in the number and arrangement of ti? contact-making parts may be made to effeet the desired electrical connections in the different switch positions, according to the conditions in each case.

In thedrawings I have indicated how various auxiliary features may be incorporated in or used with my switches. For example, they may be arranged with a spring centering device consisting of parts 76, 77, 78, 79, 80, 81 and 82 in which the roller 77 is forced against the cam-surface of part 28 so that the switch will open whenever there is nothing to hold it closed. Preferably the switch w1ll be provided with a no-voltage release coil 35 which will after the motor has been properly started, hold the switch closed until the no-voltage release coil has been deenergized which will occur when an overload relay operates or when the power supply fails or when for convenient stopping, from a remote point,the operator opens the circuit through the no-voltage release coil by a push button or switch.

I claim:

1. In an electric switch, the combination of two contact-carrying elements, means for moving about an axis one of said elements with respect to the other and means movable about an axis for maintaining said elements substantially parallel, the axes ofmotion in the two cases being substantially at right angles to each other.

2. In an electric switch, the combination of fixed and movable contact-carrying elements, an arm on which the movable element swings and a second swinging arm serving to maintain said elements substantially parallel.

3. In an electric switch, the combination of fixed and movable contact-carrying ele ments, an arm on which the movable element swings about an axis and a second arm movable about an axis and serving to maintain said elements substantially parallel, the axes of motion of said arms being substantially at right angles to each other.

Signed by me at Ampere, New Jersey, this sixteenth day of January, 1914.

HAROLD E. WHITE.

FRANCIS B. CRocKER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G.

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