US3028832A - Ultrasonic transmitter - Google Patents

Description

April 10, 1962 A. G. LAzzERY 3,028,832

ULTRAsoNTc TRANSMITTER Filed June 6, 1960 2 sheets-sheet 1 INV EN TOR. ANGEM AZZEKY :s1/wwwa;

April 10, 1962 A. G. LAzzERY l 3,028,832

ULTRASONIC TRANSMITTER Filed June 6, 1960 2 She s-Sheet 2 BY Mez.

#Train/5) niteei The present invention relates to ultrasonic transmitters and more particularly to ultrasonic transmitters of the type utilizing mechanical resonators to develop ultrasonic signals for remotely controlling the operation of television receivers and the like.

It is an object of this invention to provide an improved ultrasonic transmitter of durable construction which provides reliable trouble free operation over a period of extended use.

lt is a further object of this invention to provide an improved and durable mechanism for imparting mechanical energy to a mechanical resonating rod.

lt is still a further object of this invention to provide improved tripping means for operating a resilient striking member in a mechanical resonator type ultrasonic transmitter.

An ultrasonic transmitter constructed in accordance with the invention includes a mechanical resonating rod which is supported at its center on a suitable frame member. Striking means, including a hammer a'ixed to a resilient exciter leaf spring, is cantilever mounted on the frame member adjacent one end of the resonator. A spring-biased operating member, having an extension on which a spring-biased tripping member is fastened to pivot in one direction only, is pivotally mounted on the frame member to provide means for stressing the exciter spring. The tripping member is disposed to engage, defleet, and slidably release at a predetermined point the exciter leaf spring whereupon the hammer impinges sharply upon the resonator setting up ultrasonic vibrations therein.

On the return pivotal movement of the operating member under the urging of its biasing spring, the tripping member pivots when passing over the exciter leaf spring. After passing over the exciter leaf spring, the tripping member is forced by its own biasing spring back to its original position to engage the exciter leaf spring, whereupon the cycle of operation can be repeated.

The arrangement of the striking means and the exciter spring stressing means comprises a durable mechanism which provides reliable operation over a period of extended use, resulting in an improved ultrasonic transmitter.

The novel features which are considered to be characteristic of this invention are set forth with particularity in the appended claims. The invention itself, both as to organization and method of operation, as well as additional objects and advantages thereof will best be understood by referring to the accompanying drawing in which:

FlGURE l is a perspective View of an ultrasonic 'transmitter constructed in accordance with the invention;

FIGURE 2 is a partially broken top view of the ultrasonic transmitter with the tops of the casing and the frame member removed;

FlGURE 3 is a sectional view of the ultrasonic transmitter taken on the section lines 3--3 of FGURE 2 with the tops of the casing and the frame member replaced;

FIGURE 4 is an enlarged exploded view of the operating mechanism of the ultrasonic transmitter;

FIGURE 5 is a perspective broken away view of the resonant rod mounted on its supporting member; and

FIGURES 6, 7 and 8 are diagrammatic views showing various positions of the exciter spring stressing means and striking means during an operating cycle.

tnt @if 3,028,832 Patented Apr'. 1), 1962 Referring now to the drawing (wherein like reference numerals iwill be used to designate similar elements throughout) and particularly to FIGURE 1, an ultrasonic transmitter 11, particularly adapted for remotely controlling television receivers and the like, in cludes a casing l2 suitably contoured for hand manipulation of a pair of push buttons 13 and 14. One end of the casing l2 is hornlike or flaring in contour to achieve enhanced acoustical signal output. The ilared end portion of the casing 12. has an opening -which is covered by a suitable grille l5 having a multiplicity of apertures 15a therein to permit radiation of ultrasonic waves.

As shown in FIGURE 2, the ultrasonic transmitter 11 includes a Vpair of mechanical resonators V16 and 17 of diderent physical lengths. When the rods are struck on the ends thereof, they are excited into substantially longitudinal mode vibration to produce control signals of two different frequencies.

Referring to FIGURE 3 (and also to FIGURE 4the exploded view of the operating mechanism) the mechanical resonator 16 is centrally mounted by means of a support member 1S on a frame member 19. The frame member 19 is enclosed within the casing 12 and attached thereto 'oy a plurality of screwsltl. A flexible lever 20, supporting the push button l, is fastened at one end (the right hand `end in FGURE 3) between the casing l2 and the frame member 19. The other end of the iiexible lever Ztl is left free in order to transmit the force exerted on the push button 13 to the operating mechanisrn of the transmitter l1. A resilient exciter leaf spring 21 is cantilever mounted on the frame member 19 and supports at is free end a hammer 22 which is positioned adjacent to, but spaced from, one end of the mechanical resonator le to provide striking means for the resonator 16.

A pair of leaf springs 23 and 24 are also fastened at the mounting pointv of the cantilevered exciter spring 21. The spring 23 is positioned on one side, the forward side, of the exciter spring 2i, which is the side from which the hammer 22 extends, to provide simplified damping of the exciter spring 21. The spring 23 is cantilever mounted so that in a rest position it is supported Hush against the exciter spring 21. The similar spring 2d is similarly mounted and positioned on the rcverse side of the exciter spring 21 to provide additional structural support. The springs 23 and 24 are not under stress when the arrangement is in the rest position. The inclusion of the spring 2e effectively causes a redistribution of the stresses applied to the exciter spring 21 along its length, instead of concentrating them at its cantilevered point, thereby increasing the reliability of operation when used over an extended period of time. The inclusion of the damping spring 23 is to prevent repeated strikings of the mechanical resonator 16. This spring 23 aids in urging the return of the exciter leaf spring 21 and its hammer 2?. toward the rest position as the hammer Z2 rst rebounds after a blow on the resonator 16. Further, if the hammer 22 starts to pass its rest position after rccound, moving `away from the resonator 16, the support spring 2.4i tends to absorb its kinetic energy. lf, pendulum like, the hammer 22 and the exciter spring 21 again move toward the resonator i6, the damping spring 23 now absorbs most of the remaining kinetic energy and tends to restore the exciter spring 21 and its hammer 22 to the rest position. In this way'multiple striking of the mechanical resonator 16 by the hammer 22 is prevented.

Excited spring stressing means, including a bifurcated operating member 2S having an extension arm 25a with a tripping member 26 mounted thereon, is provided to activate the striking means. The bifurcated operating member 25 is pivotally attaebed to the frame member by means of a shaft Z7, and the base portion 2512 of the operating member 25 is urged into intimate contact with the free end of the lever 20 by a biasing spring 2,3. The lever 26, in conjunction with the casing 12, limits the pivotal movement of the operating member 25 to a rest position. The tripping member 26 is mounted on the extension arm 25a of the operating member 2S by means of a pin 29 and contoured to pivot in one direction away from its rest position, but not beyond the rest position in the other direction as will hereinafter be described in greater detail. A biasing spring 3i) retains the tripping member 26 in the limited position of its pivotal movement when unactivated.

Referring to FIGURE 5, the mechanical resonating rod 16, which is made of an aluminum alloy having an inherently low internal damping factor, has a circumferentially cut groove 31 at its physical center. The support member 13 is provided with a resilient mounting bracket 32 having a plurality of resilient tines 33 spaced about an aperture thereon. The tines 33 snap into the groove 3l and support the resonator for substantially longitudinal mode vibration. Suitable means are provided for aiixing the support member 18 to the frame member 19.

The method of mounting reduces the possibility of damping the resonator 16. The resonator 16 when struck on the end sets up vibrational waves which have a nodal point at the physical center. Therefore, by mounting the resonator 16 as closely as possible to the nodal point, a minimum of vibrational energy is absorbed by the support member 1S. The resiliency of the mounting bracket 32 and the tines 33 also reduce absorption of acoustical wave energy. The annular groove 31 permits the resonator 16 to rotate within the tines 33 when struck by the hammer 22. It has been found that any interference with this rotation also causes a damping of the acoustical wave energy and reduces the control signal output.

An operator can cause the transmitter to radiate an ultrasonic control signal of one frequency by depressing the push button 13 on the ultrasonic transmitter 11. The manual force exerted on the push button 13 urges the exible lever 2) against the base portion 25b of the operating member 25. In response to the urging of the llexible lever 20, the operating member 25 pivots in a clockwise direction, as shown in FIGURE 3, about the shaft 27. As viewed in FIGURE 6, the upper left hand edge, or corner, 26a of the tripping member 26 engages the end of the exciter leaf spring 21 which is remote from the cantilever mounting point. Since the right hand edge 26h of the tripping member 26 is llush mounted against the extension arm 25a, the tripping member 26 cannot pivot clockwise from its rest position. Therefore the spring 21 is deflected to the left as the operating member 25 is pivoted clockwise. Energy is stored in both the exciter spring 21 and the support spring 24 during the pivotal movement of the operating member 2S.

As shown in FIGURE 7, the edge 26a of the tripping member 26 describes an arc of radius r1, when the operating member 2S is pivoted. The exciter leaf spring 21, due to the cantilever mounting on the frame member 19, describes an are of radius r2 when deflected by the tripping member 26. At a point determined by the intersection of the arcs of radii r1 and r2, the exciter leaf spring 21 slidably disengages or slips off the tripping member 26 and the stored potential energy causes the exciter spring 21 to snap forward with the hammer 22 impinging sharply upon the edge of the resonator 16. Multiple contacts between the hammer 22 and the resonator 16 are precluded by the damping spring 23. In response to the shock excitation, the resonator 16 vibrates in a substantially longitudinal mode. The acoustical energy is radiated to actuate a desired response in remotely controlled apparatus.

Upon the slidable release of the exciter leaf spring 21, mechanical shock is felt by an operator so that he is made instantly aware of the fact that a control signal is being transmitted. Thereupon, the operator may remove the force exerted on the push button 13 and the operating member 25 is urged back to its rest position by the biasing spring 28. As shown in FIGURE 8, the tripping member 26 pivots, in a counterclockwise direction, under the exciter leaf spring 21 permitting the operating member 25 to return to its rest position. The biasing spring 3i) then returns the tripping member 26 to its own initial rest position whereupon the operating cycle can be rcpeated.

In accordance with the invention an ultrasonic transmitter is provided with an improved and durable mechanism for imparting percussive energy to a mechanical resonator to give reliability of operation over an extended period of use.

What is claimed is:

l. In an ultrasonic wave transmitter including a mechanical resonator mounted on a frame member and excited into vibration by striking means including a hammer affixed to a resilient exciter leaf spring, the combination comprising, a casing having one open flared end for radiating ultrasonic waves generated by said rcsonator and for impedance matching to the air load thereon, means for fastening said frame member to the inside of said casing, a bifurcated operating member pivotally mounted on said frame member at the junction of its bifurcations, means for cantilever mounting said exciter spring on said frame member between the pivotal mounting point of said operating member and one end of said resonator so that the distal end of said exciter spring is positioned adjacent one end of a first one of the bifurcations of said operating member and said hammer is positioned adjacent to but spaced from the end of said resonator, first and second leaf springs cantilever mounted on either side of said exciter spring at the mounting point thereof, for reducing the stress on said exciter spring at the mounting point thereof when deflected and for providing means for damping said exciter spring, a resilient lever cantilever mounted for engaging the second one of the bifurcations of said operating member, means for biasing said operating members into intimate contact with said lever, said lever and said casing providing a rest position for said operating member, a spring-biased tripping member pivotally mounted on said first bifurcation and disposed to engage the distal end of said exciter spring, dellect and then slidably release said exciter spring at a predetermined point when said operating member is pivoted by a force applied to said lever, said exciter spring upon being slidably released from said tripping member causing said hammer to impinge sharply against said one end of said resonator setting up vibrations therein, and means on said rst bifurcation defining a stop position which prevents said tripping member from pivoting while deilecting said exciter spring but which permits said tripping member to pivot over without stressing said exciter spring when said operating member is urged by said biasing means to its rest position upon the removal of the force applied to said lever.

2. In an ultrasonic wave transmitter including a. mechanical resonator mounted on a frame member and excited into vibration by striking means including a hammer ai'lixed to a resilient exciter leaf spring, the combination comprising a bifurcated operating member pivotally mounted at the junction of its bifurcations, means for cantilever mounting said exciter spring member between the pivotal mounting point of said operating member and one end of said resonator so that the distal end of said exciter spring is positioned adjacent one end of a rst one of the bifurcations of said operating member and said hammer is positioned adjacent to but spaced from the end of said resonator, a resilient lever cantilever mounted on said frame member for engaging the second one of the bifurcations of said operating member, means for biasing said operating member into intimate contact with said lever, a spring-biased tripping member pivotally mounted on said first bifurcation and disposed to engage the distal end of said exciter spring, deflect, and then slidably release said exciter spring at a predetermined point when said operating member is pivoted by a force applied to said lever, said exciter spring upon being slidably released from said tripping member causing said hammer to impinge sharply against said resonator setting up vibrations therein, and means on said irst bifurcation defining a stop position which prevents said tripping member from pivoting while deflecting said exciter spring but which permits said tripping member to pivot over Without stressing said exciter spring when said operating member is returned to a rest position.

3. In an ultrasonic transmitter including a rod type mechanical resonator mounted for substantially longitudinal mode vibration on a frame member and excited into vibration by being struck on one end by a hammer aixed to an exciter leaf spring cantilever mounted on the frame member in proximity to said one end of the resonator, the combination comprising a bifurcated operating member pivotally mounted on said frame member, a lever pivotally mounted on said frame member, means for biasing said operating member into intimate contact with said lever, said lever and said frame member constituting means for limiting the pivotal movement `and describing a rest position for said operating member, and a tripping member pivotally mounted on a bifurcation of said operating member, said tripping member disposed to engage, deflect and i slidably release said exciter spring when said operating member is pivoted, said tripping member pivoting over said exciter leaf spring when said operating member is returned to its rest position to prevent stressing said exciter leaf spring.

4. In an ultrasonic transmitter including a rod type mechanical resonator mounted for substantially longitudinal mode vibration on a frame member and excited into vibration by being struck on one end by a hammer aixed to an exciter leaf spring cantilever mounted on the frame member in proximity to said one end of the resonator the combination comprising a casing having one open flaredend portion, means fastening said frame member to the inside of said casing, a spring-biased bifurcated operating member pivotally mounted on said frame member, means extending from the outside of said casing to the inside thereof for actuating said operating member, and a tripping member pivotally mounted on an extension of said operating member, said tripping member disposed to engage, deect, and slidably release said exciter spring when said operating member is pivoted, said exciter spring upon release causing said hammer to impinge sharply against said mechanical resonator setting up vibrations therein which are radiated through said open flared end portion of said casing.

5. In an ultrasonic wave transmitter including a mechanical resonating rod mounted on a frame member and excited into vibration by a striking thereof, the combination comprising, means for centrally supporting said resonating rod on said frame member, said supporting means including a support member and a bracket mounted thereon and having a plurality of tines dening an aperture on said bracket, said resonating rod having a groove transversely cut around the circumference of tbe physical center thereof to permit rotation Within said tines, a resilient striking lmember cantilever mounted on said frame member, and stressing means for said resilient striking means, said stressing means pivotally mounted on said frame member and disposed to engage, deflect and slidably release at a predetermined point said resilient striking means whereby said resilient striking means impinges sharply against said one end of said rod causing longitudinal mode vibrations to be s'et up therein as well as causing said resonating rod to rotate Within said tines.

References Cited in the file of this patent UNITED STATES PATENTS

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