US 2924677 A
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Feb. 9, 1 960 D. H. LANCTOT 2,924,677
HIGH FREQUENCY SWITCHING UNIT Filed Nov. 20, 1958 3 Sheets-Sheet 1 INVENTOR. DONALD H. LANCT'OT ATT ORN E YS 1960 D. H. LANCTOT 2,924,677
HIGH FREQUENCY SWITCHING UNIT I Filed Nov. 20, 1958 3 Sheets-Sheet 2 'IIIIIIIIIIIJ\ I IN VEN TOR. DONALD H. LANCTOT BY was MZdiu' v Ameusrs Feb. 9, 1960 D. H. LANCTOT 2,924,677
HIGH FREQUENCY swncnmc UNIT Filed Nov. 20, 1958 :s Sheets-Sheet 3 IN VEN TOR. DONALD H. LANCTDT BY m fldza' w ATTORNEYS United States Patent 2,924,671 HIGH FREQUENCY SWITCHING UNIT Donald H. Lanctot, Malibu, Califl, a'ssignoi to Don-Lan Electronics Co., Inc, a corporation of (Ialifornia Application November 20, 1958, Serial No. 775,250 8 Claims. Cl. 200-24 This invention relates generally to electrical switches and more particularly to an improved unit for switching high frequency electrical energy from an input coaxial line to two or more output co-axial lines.
Switches of the type under consideration are particularly well adapted for switching high power, high frequency electrical energy between two or more antennas such as employed in radar systems. In certain instances, there may .be provided a single reflecting type antenna structure fed by two separate co-axial lines. arranged to deliver energy pulses alternately to the antenna from different focus points so that the beam or lobe from the antenna is shifted between two limits. In other instances, there may be several antennas which are sequentially energized to'provide an eifective lobe sweeping characteristic.
It is extremely important in all such switches of the foregoing type to minimize losses and noise, provide proper isolation between the various output lines, and maintain a proper impedance match between the input and the various output lines 'to which the energy is distributed.
Power losses from leakage and poor impedance matching can best be overcome by providing a positive connection in the switching unit as by a metal to metal contact between the various inner conductors of the coaxial lines. On the other hand, the absence of a metal to metal contact between the other lines insures excellent isolation. Heretofore, the problem of making and breaking metal to metal contacts between the various inner conductors of co-axial lines at a sufficiently high lobing frequency to be useful, has proven very difiicult. If capacitance coupling is resorted to, the usual losses across the capacitances are incurred and the various energy portions distributed among the output lines are not positively defined.
Bearing the foregoing in mind, it is a primary object of the present invention to provide a greatly improved type of high frequency switching unit particularly useful in lobing operations in which the various inner conductors of co-axial lines are positively connected by a metal to metal contact so that discrete and equal or proportioned amounts of energy may be distributed between the various lines with a minimum of electrical loss and at a desired frequency rate. I
More particularly, objects are to provide an improved lobing switch of the foregoing type which is positive and consistentthroughout in operation, the metal to metal contact points automatically compensating themselves for wear, which exhibits excellent isolation between the connected and disconnected lines, which has a relatively good impedance match between the connected lines, and which is characterized by high reliability, low noise level, and low maintenance.
Another important object is to provide a switch in which the connection between one output co-axial line and the input line may be made prior to the breaking of Eatented Feb. 9, 1960 the connection between a previously connected output co-axial line and the input line.
An auxiliary object to the above object is to provide simple means for enabling the breaking of a connection prior to the making of another so that the switch finds use in certain applications in which this characteristic is desired.
These and many other objects and advantages of this invention are attained by providing a switching unit including a basic metallic block member including output connections for receiving the output co-axial lines between which energy is to be switched. An input connector has its outer conductor connected to this block and its inner conductor projecting into a central cavity in the block. This inner conductor is centrally secured in a stationary position within the cavity. The inner conductors of the various output connectors extend laterally through suitable bores in the block to terminate short of the stationary conductor of the input connector. (Io-operating with each of the inner conductors of the output connectors is a conducting sleeve contactor arranged to telescope over the inner conductors and thus be moved into or out of engagement with the center stationary conductor. Suitable biasing means normally urge the sleeve contactors towards the stationary concluctor.
A drive means including either an insulative or conducting roller is arranged to revolve about the stationary conductor within the cavity of the block and sequentially move the contacting sleeves into and out of engagement with the inner conductor. The roller can be arranged to revolve about the center conductor extremely rapidly so that switching can take place at a desired lobing frequency. Further, wear of the contact surfaces of the various sleeve contactors and central conductor will be compensated as a consequence of the biasing means continuously urging the sleeve contactors towards the central conductor. In a preferred embodiment the central conductor includes secondary spring contacts to avoid chatter and minimize noise upon contact.
A better understanding of the invention will be had by referring to a preferred embodiment thereof as illustrated in the accompanying drawings in which:
Figure 1 is a cutaway elevational view partly in cross section of the complete lobing switch of this invention;
Figure 2 is a cross section of the switch taken in the direction of the arrows 22 of Figure 1;
Figures 3 and 4 are cross sectional views similar to Figure 2, but showing the movable parts of the switch in different positions.
Figure 5 illustrates in perspective a modified type of center conductor;
Figure 6 is a top plan view of the conductor of Figure 5 in one contact making position; and,
Figure 7 is an enlarged fragmentary view of a portion of Figure 1 showing a modified roller and sleeve.
Referring first to Figure 1, the switch includes a casing 10 hermetically sealed to a metallic block '11. The front face of the block 11 is threaded to receive an input co-axial connector 12. Two output co-axial connectors 13 and 14 are in turn secured to opposite side faces of the block 11. The block 11 connects all of the outer conductors of the input and output co-axial connectors together and is normally at ground potential.
Housed within the casing 10 is a motor 15 arranged to be energized by suitable power input leads 16 from an external connector 17. Motor 15 includes a shaft 18 extending into a part of the block 11 through a suitable journal bearing 19. The end of shaft 18 is provided with a driving member 20 which may constitute a simpledisc arranged to be rotated about a central axis coinciding with the axis of the input connector 12. The disc 20 roller.
carries a roller shaft 21 rotatably mounting an insulative roller 22 eccentrically positioned in radially spaced, parallel relationship to the axis of the disc. The arrangement is such that when the driving member 20. is rotated by the motor shaft 18, the roller 22 will revolve about the central axis of the motor shaft to describe a circular locus within a central cavity 23 in the block member 11. The connector 12 includes an inner stationary conductor 24 projecting centrallywithin this cavity 23 along the axis of rotation of the disc 20 so that the roller 22 revolves in spaced, parallel relationship about this stationary conductor.
Laterally movable towards the stationary conductor 24 are two switching pistons in the form of insulative cylindrical members 25 and 26. These members are mounted 'for back and forth motion within bores 27 and 23 respectively axially aligned with the output connectors 13 and 14 in the block 11. The cylindrical members 25 and 26 are of insulating material preferably of a light plastic and are biased towards the stationary center conductor 24 by springs 29 and 30. Essentially, these mem bers serve as telescoping guides, respectively, for split sleeve contactors including a split sleeve portion 31 and contacting head 32 for the member 25 and a split sleeve portion 33 and contacting head 34 for the member 26.
The sleeve portions 31 and 33 telescopically ride over the inner conductors 35 and 36 respectively of the output connectors 13 and 14. The outside diameter of each of the insulative cylindrical members 25 and 26 is at least as large as the diameter of the circular locus described by the roller 22 so that the roller 22 may engage the ends of the plastic members 25 and 26 in its travel about the stationary conductor 24.
The operation of the lobing switch of Figure 1 will be clearly understood by referring to Figures 2, 3 and 4. Figure 2 illustrates the same position of the movable components as shown in Figure 1. In this position, it will be noted that the input connector 12 of Figure 1 has its inner conductor 24 electrically connected to the inner conductor 36 of the output connector 14 through the medium of the split sleeve portion 33 and contacting head 34. In this position, high frequency energy will be easily conducted from the input co-axial line 12 to the output co-axial line 14. The output connector 13, on the other hand, will be substantially completely isolated as a consequence of the large gap between the inner conductor 24 and the inner conductor 35 of this output connector.
As the roller 22 on the shaft 21 moves in a counter clockwise direction as indicated by the arrow in Figure 2,
it will assume the position shown in Figure 3, the biasing spring 29 urging the cylindrical piston member 25 and associated split sleeve 31 in a direction to follow the In the position illustrated in Figure3, the contact head 32 will engage the inner stationary conductor 24. By making the diameter of the roller 22 as indicated at d slightly less than the diameter of the stationary center conductor 24, contact between the contacting head 32 and conductor 24 can be achieved prior to breaking of contact between the conductor 24 and the contacting head 34. 7
As the roller 22 continues in its revolving movement about the stationary center conductor 24, it will engage the end of the cylindrical piston member 26 urging this member to the right as shown in Figure 4 and thus breaking the connection between the contacting head 34 and center conductor 24. In the meantime, the contacting head 32 and conductor 34 are retained in metal to metal engagement by the pressure of the biasing spring 29.
As the roller 22 continues in a counter clockwise direction from the position in Figure 4 back towards the positions illustrated in Figures 1 and 2, the contacting head 34 will make engagement with the center stationary conductor 24 prior to separation of the contacting head 32. p
It will be evident that by rotating the disc 20 of Figure 1 very rapidly, the roller 22 can be made to complete several hundred revolutions per minute thereby achieving extremely rapid switching between the input connector 12 and the two output connectors 13 and 14. Further, it will be evident that by making the diameter of the roller 22 slightly larger, that is, larger than the external diameter of the stationary center input conductor 24, a breakbefore-make action can be achieved, the various discrete energy portions distributed to each of the output lines being separated bya small time gap in which no energy is passed to either line. At all events it will be evident as a consequence of the described construction that equal portions of energy will be consistently delivered to each of the two output lines. Moreover, an excellent physical metal to metal contact will always be assured notwithstanding physical wear since the two contacts 32 and 34 are constantly being urged towards the center conductor by the biasing springs.
Preferably, the entire central cavity within the block 11 is filled with a dielectric oil as indicated at 37 in Figure 1 so that proper impedance matching, heat dissipation, and are quenching are assured. 7 Moreover, the continuous movement of the roller about the cavity serves to pick up the oil and maintain all moving parts properly lubricated.
' The inner conductors 35 and 36 are tapered as shown so that only the head portions thereof slidably engage the split sleeves 31 and 33 to minimize friction.
The metallic springs 29 and 30 themselves are designed so that when in their expanded condition they form a proper impedance matching section of co-axial line with the tapered portions of the inner conductors. On the other hand, when these springs are compressed there results a mis-matching of this'section so that additional isolation between the center conductor and disconnected output connector is provided.
To help minimize electrical noise as a consequence of possible chatter when metal to metal contact is made, the center conductor 24 of Figures 1, 2, 3 and 4 may be modified as shown in Figure 5.
In Figure 5, the center conductor from the input coaxial connector is designated 38 and includes two diametrically opposite lateral slots 39 and 44 cut from the top and terminating short of the lower end ofthe conductor. Theseslots respectively accommodate secondary contacts in the form of metallic bands 41 and 42 secured within the lower ends of the slots and biased radially outwardly as shown. The top portions of the bands are bent, to horizontal positions, having a length equal to the depth ofthe slots and terminating short of the end walls of the slots by a distancecorresponding to the radially protruding-distances of the-bands as a consequence of the radially outward bias.
By this arrangement, the contacting heads of the inner conductors will engage the bands prior to engaging the center conductor and then both will be engaged. Thus,
referring to Figure 6, the contacting-head 32 of the pis- In certain applications, the roller 22 of Figures 1, 2, 3 Q
and '4, may be made of conducting material and the insulated cylindrical piston members provided with conducting portions so that the roller will ground or short circuit'the disengaged contacting head and thus further improve electrical isolation. I I v I Referring to Figure 7, for example, there is shown a conducting roller 43 mounted on the shaft 21. The cylindrical member for the inner conductor 35, split sleeve 31 and contacting head 32, however, is modified to include in addition to an insulated portion 44, a conducting band 45 engaging the spring 29 and in contact with the metallic block 11.
By the foregoing arrangement, the metallic roller 43 will ground the contacting head 32 to the metallic block 11 through the conducting band 45 and will thus short circuit the inner conductor of the disconnected output coaxial line to its outer conductor.
From the foregoing description of Figures 1 through 7, it will be evident that the desired features of good impedance matching between connected lines, good isolation between the connected and disconnected lines, and a low noise level in the device are all realized.
While the embodiment of the invention described relates to the switching of energy from an input co-axial line to only two output co-axial lines, it will be evident that the cavity 23 and both the stationary inner conductor 24 and the roller 22 could be modified in dimensions to allow other output co-axial connectors to be accommodated within the cavity 23 and thus operated by the same roller actuating the switching piston members 25 and 26. Such additional co-axial output lines and their cooperation with the principal driving structure is a mere multiplication of parts and will readily be understood to fall within the scope and spirit of the present invention.
Other modifications that fall within the scope and spirit of this invention will also readily occur to those skilled in the art. The high frequency switching unit is, therefore, not to be thought of as limited to the particular embodiment set forth for illustrative purposes.
What is claimed is:
l. A unit for switching high frequency electrical energy from an input co-axial line connector between at least two output co-axial line connectors, comprising, in combination: a conducting block member having a central cavity and oppositely directed bores extending from said central cavity to opposite exterior sides of said block member, said input co-axial line connector having its outer conductor connected to said block and an inner stationary conductor projecting centrally within said cavity, said output co-axial line connectors having their outer conductors connected to and forming a continuation of said bores and their inner conductors extending co-axially within said bores and terminating short of said stationary conductor; conducting sleeve contactors mounted for telescoping movement over said inner conductors respectively; biasing means urging said sleeve contactors towards said stationary conductor; and driving means projecting into said central cavity for alternately moving said sleeve contactors into and out of engagement with said stationary conductor.
2. The subject matter of claim 1, in which said driving means includes a roller extending in a direction parallel to and radially spaced from said stationary conductor; a driving member; and a motor secured to said block member and connected to rotate said driving member about an axis coinciding with said stationary conductor, said roller being eccentrically connected to said driving member so that said roller revolves about said stationary conductor to move said sleeve contactors into and out of engagement with said stationary conductor.
3. The subject matter of claim 2, in which said stationary conductor includes diametrically opposite lateral slots; and conducting bands secured in said slots and biased to protrude radially outwardly from said slots to engage the head portions of said sleeve contactors prior to engagement.
4. The subject matter of claim 2, including cylindrical members dimensioned for reciprocal movement in said bores and surrounding said sleeve contactors for guiding said sleeve contactors in back and forth motion, the diameter of said cylindrical members being at least equal to the diameter of the circular locus described by said roller.
5. The subject matter of claim 4, in which said roller is conductive and outer portions of said cylindrical memhere are conductive so that when said roller engages one of said sleeve contactors it also engages the conducting portion of the corresponding cylindrical member to electrically short circuit the corresponding inner conductor to which said one of said sleeve contactors is connected to its outer conductor.
6. The subject matter of claim 3, in which the diameter of said roller is less than the diameter of said stationary conductor whereby one of said sleeve contactors engages said stationary conductor prior to the separation of the other of said sleeve contactors from said stationary conductor by said roller.
7. The subject of claim 4, including a casing structure covering said motor and hermetically sealed to said block member; and oil filling said central cavity.
8. A unit for switching electrical energy from an input line between at least two output lines comprising, in combination: a stationary conductor for connection to said input line; two movable conductors for connection to said output lines respectively, said movable conductors being positioned on opposite sides of said stationary conductor for movement towards and away from said stationary conductor; biasing means urging said movable conductors towards said stationary conductor; and driving means including a roller mounted for revolving movement about an axis coinciding with said stationary conductor and arranged alternately to move said movable conductors out of contact with said stationary conductor, whereby electrical energy at said input line is alternately switched between said two output lines.
References Cited in the file of this patent UNITED STATES PATENTS 2,286,611 Farmer June 16, 1942 2,709,725 Bieber et al. May 31, 1955 2,814,696 Cockerham Nov. 26, 1957 2,816,198 Cherry Dec. 10, 1957