US1743471A - High-voltage switch - Google Patents

Description

Jan. 14, 1930. H, MENEFEE 1,743,471

HIGH VOLTAGE SWITCH Filed March 20. 1924 2 Sheets-Sheet 1 Jan. 14, 1930. H. R. MENEFEE HIGH VOLTAGE SWITCH Filed March 20, 1924 2 Sheets-Sheet 2 Patented Jan. 14, 1930 UNITED STATES PATENT OFFICE HARRY R. MENEFEE, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COM- PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK HIGH-VOLTAGE SWITCH Application filed March 20, 1924. Serial No. 700,548.

This invention relates to high voltage switches such as are used in high power radio transmission.

It is an object of the invention to provide a new and improved high voltage switch capable of different degrees of adjustment, whereby circuit changes in a high voltage circuit may be effected with ease and with safety.

Another object of the invention is to pro vicle a switch of the above type which is simple in construction and which employs a small number of operating parts which are readily accessible for cleaning and adjustment.

The invention is adapted for use in radio transmitters for long distance transmission in which it is not uncommon for the high frequency energy developed in the antenna to amount to several kilowatts. The capacity and inductance of an antenna are generally of such an order of magnitude that the voltages developed at this energy are very high, and may frequently amount to 50,000

volts or more. In such systems it is desir-.

able to employ ahigh voltage switch to change the connections of the circuits associated with the oscillation circuit for shift-,

ing the wave-length, varying the coupling,

or otherwise adjusting the set to different able switch arm in any of its adjusted posi tions and for automatically shutting off the current when the arm is released from its locked position preparatory to adjustment, thereby preventing dangerous sparking between the stationary contacts and the rotat able bridging brush. This construction makes for reliability, safety and efficiency in operation, and possesses the advantage of shield the contact mechanisms which are mounted in a box-like frame comprising a pair of rectangular end plates 6 and 7 joined together at the corners by means of angular braces 8. The panel 5 and mounting plates 6 and 7 are preferably constructed of micarta or other suitable material, and may be mount ed on any suitable standard or framework, not shown. The control wheel 9 by means of which the control mechanisms are actuated is mounted on the end of a main shaft 10. A sleeve 11 keyed to the shaft 10 by means of a set screw 12 acting in an elon ated slot 13 passes through a bearingbushing 1-l in the panel 5. The sleeve 11 is provided with an extending index pointer 15 which is adapted to move over a scale on the front of the panel 5.

A collar 16 is keyedto the shaft 10 by means of a pin 17 at a point between the panel 5 and the mounting plate 6. A bushing 18 is fastened to mounting plate 6 in any suitable manner and is provided with an outer circular flange 20 resting against the outer face of the plate 6. A sleeve 21 is loosely mounted on the shaft 10 and passes through the bush ing 18, a pair of ball races 22 and 23 serving as a bearing therefor. Collars 24 and 25 are threaded to the ends of the bushing 18 to confine the ball races 22 and 23 in position. A pulley 26 is keyed t0 the sleeve 21, by means of a key 27, intermediate the collar 16 and the flange 20 of the bushing 18, and is retained in its longitudinal position on the sleeve 21 by means of a retaining nut 28 threaded t0 the sleeve 21. A pair of pins 29 and 29 are carried by the collar 16, preferably separated a distance of 180 degrees, and extend through corresponding holes in alignment therewith in the pulley 26. A plurality of tapered holes 30 are formed an equal distance apart in the outer face of the flange and are adapted to receive the tapered end of the pin 29. The shaft 10 is slidable longitudinally in the sleeve 21, but the sleeve 21 while rotatable in the bushing 18 is prevented from sliding therein by the ball races 22 and 23 and the collars 24 and 25. With the parts in the position shown in Fig. 1, pin 29 is in engagement with one of the holes 30 in the flange 20 of the fixed bushing 18 and hence the pulley 26, collar 16 and shaft 10 are held against rotation. The pin 29 is shorter than the pin 29 and is not provided with a tapered end engaging the holes 30. The function of the pin 29' is simply to assist in driving the pulley 26. TVhen the control wheel 9 is pulled outward, the shaft 10 slides in the sleeve 21 carrying with it the collar 16 and hence withdrawing the pin 29 from the hole 30 with which it is in engagement in the flange 20. The pins 29 and 29 while slidable in the aligned holes in the pulley 26 cannot be withdrawn therefrom, since the range of travel of the shaft 10 is defined by the distance between the hub of the collar 16 and the inner edge of the bearing 11, which distance is shorter than the portions of the pins 29 and 29 which extend through the pulley 26. It will thus be seen that when the pin 29 has been withdrawn from the hole in the flange 20 with which it is engaged any rotation of the control wheel 9 will be imparted to the collar 16 and thence by means of the pins 29 and 29 to the pulley 26. The rotation of the pulley 26 causes the rotation of a cable 32 which is clamped to the pulley 26 by means of a clamp and screw 31. The cable 32 is adapted to operate other switches to shift the wave-length, tuning control, or otherwise adjust the parts of a transmission system (not shown). The rotation of the pulley 26 is also imparted to the sleeve 21 wluch is keyed to rotate therewith, the rotation of the sleeve also causing the rotation of contact arms as hereinafter described.

A collar 34 having a pair of oppositely disposed switch arms 35 and 36 is keyed to the sleeve 21 by means of a key 37 and is clamped firmly in place by means of a lock nut 38 which is screw threaded to the end of the sleeve 21. A pair of high voltage insulators 39 are rigidly mounted on each of the depending switch arms 35 and 36. The high voltage insulators 39 are preferably mounted side by side on the switch arms 35 and 36 in a plane perpendicular to the shaft 10, or in other words in'the plane in which the switch arms are moved. This construction materially reduces the mechanical strain on the insulators. A plurality of contact terminals 40 are also mounted on the mounting plates 6 and 7 and are arranged in a circle facing each other on opposite sides of the insulators 39, at the same radial distance from the axis of the insulators 39. Each of the contact terminals 40 on the mounting plate 7 comprises a metal cap 41 mounted on the end of a high voltage insulator. The caps 41 are cup-shaped to provide a cam surface to raise the brushes 44 when they come in engagement therewith. Several of thecontact terminals on the mounting plate 6 are also provided with similar cupshaped caps 41 as shown in Figs. 1 and 2. An arcuate contact ring 42 is also mounted on several adjacent terminals on the plate 6 in the arc of a circle as shown in Fig. 2. I

A contact brush 44 is mounted between the insulators 39 on each of the contact arms 35 and 36. These contact brushes are bentadjacent their extremities to bridge the space between the contact terminals 40 on the mounting plates 6 and 7 These bridging brushes are of any suitable flexible material and preferably bear upon the center portions of the contact caps 41 and contact ring 42, to insure a good contact between the various contact terminals.

The portion of the shaft 10 to the right of the collar 34 in Fig. 1 is considerably reduced in cross-section and bears in a bushing 46 in the mounting plate 7. This reduced portion of the shaft is provided at its extremity with a knob 47 which bears against the cam formed on a switch blade 48 to hold the switch blade in engagement with a contact member 49. When the shaft 10 is pulled outward by means of tension exerted on the control wheel 9, the knob 47 on the end of the shaft moves forward into a circular recess 50 formed in a block 51 on the outer side of the mounting plate 7. VVh-en the knob 47 thus recedes from the position shown in Fig. 1, the switch blade 48 is moved under the action of a coil spring 52 out of engagement with the contact 49 and into engagement with a contact 53. A switch of this general character may be employed in a low voltage circuit (not shown) for controlling the operation of means adapted to cut off the power to the main contact terminals when the control wheel 9 is withdrawn from its locked position preparatory to adjustment, thereby preventing dangerous sparking between the stationary and rotatable contacts. The switch 48 and associated elements may be enclosed in a protecting scribed are to be considered as'merely illusi? trative of the invention and are not intended to limit the scope thereof. The invention is capable of many modifications such as will be obvious to anyone skilled in the art and which come within scope of the invention as defined by the appended claims.

lVhat is claimed is: 1. A switch device comprising a pair of mounting plates, a hub member secured to one of said plates, a sleeve rotatably mounted in sald hub, a shaft slidably mounted in said sleeve, contacts mounted on each of said plates, brushes carried by said sleeve, means for rotating said sleeve for moving the brushes in engaged relation with said contacts, and automatically operating means for imparting movement to the first mentioned means for locking the brushes in said engaged relation. 2. A switch device comprising a pair of mounting plates, a hub member secured to one of said plates, a sleeve rotatably mountedtherein, a shaft slidably mounted in the rotatable sleeve, contacts mounted on said plates and disposed in circular rows, brushes carried by said sleeve and normally bridging a number of contacts in said rows, means for normally locking the brushes in position on said contacts, and means for imparting a twoway movement to said shaft for unlocking and changing the position of the brushes on said contacts.

In witness whereof, I hereunto subscribe my name this 19th day of March, A. D. 1924. HARRY R. MENEFEE.

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