US 3831548 A
A resonator and resonator combination for continuously producing ultrasonic vibrations of frequencies effective to drive away pests, e.g., rodents. The resonator has a housing provided with an internal cavity and an outwardly flaring horn in communication with and spaced from said fluid jet producing means. A rigid airfoil, which may be integral with said housing, projects into the path of flow of fluid from the jet producing means to the jet obstruction means. The resonator can be used in combination with a means to continuously supply air under pressure to the jet producing means and characterized by cycle pulsation to cyclically vary the amplitude of the ultrasonic vibrations, said means preferably comprising an expansible chamber axially aligned with and closely connected with said jet producing means.
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Description (OCR text may contain errors)
United States Patent 1191 Droege 111 3,831,548 1451 Aug. 27, 1974 PEST CONTROL DEVICE 22 Filed: Dec.29, 1972 21 Appl. No.: 319,448
 US. Cl 116/22 A, 43/171, 417/413  Int. Cl. G08b 9/00  Field of Search ..1l6/137, 137 A, 22 P,
116/DIG. 18;43/124, 17.1; 340/15, 16, 340/56; 417/413, 480
FOREIGN PATENTS OR APPLICATIONS 4/1970 Great Britain 116/137 A 48,599 6/ 1940 Netherlands 116/13'7 A Primary Examiner-Louis J. Capozi  ABSTRACT A resonator and resonator combination for c0ntinuously producing ultrasonic vibrations of frequencies effective to drive away pests, e.g., rodents. The resonator has a housing provided with an internal cavity and an outwardly flaring horn in communication with and spaced from said fluid jet producing means. A rigid airfoil, which may be integral with said housing, projects into the path of flow of fluid from the jet producing means to the jet obstruction means. The resonator can be used in combination with a means to continuously supply air under pressure to the jet producing means and characterized by cycle pulsation to cyclically vary the amplitude of the ultrasonic vibrations, said means preferably comprising an expansible chamber axially aligned with and closely connected with said jet producing means.
15 Claims, 6 Drawing, Figures PATENTED M18 2 71974 slmwz FIG. 3
BACKGROUND OF THE INVENTION The present invention relates to pest control devices and particularly to a pest control device that emits ultrasonic sound waves from a fluid operated resonator and functions effectively to drive away pests, e.g., birds, rodents and insects, by the emission of ultrasonic sound waves that are produced by fluid pressures as low as l p.s.i.g.
Fluid operated jet resonators for controlling pests by the emission of ultrasonic sound waves that operate under the action of a relatively low fluid pressure, as exemplified by US. Pat. No. 3,188,999 to Robert W. Baxter, granted Mar. 1 l, 1963, are known in the prior art and constitute a substantial improvement over other prior known resonators that require the supply of pressurized fluid thereto at approximately 80 p.s.i.g. in order to obtain reasonable operating efficiency. In the fluid resonator disclosed in the Baxter patent, however,
the distance between the discharge end of the fluid jet producing means and the cup into which said fluid jet is received must be accurately adjusted and maintained and the curvature of the airfoil over which said fluid jet travels in its path between the fluid jet producing means and said jet receiving cup must be shaped so that the velocity of said fluid jet is increased if the frequency of the ultrasonic sound produced by the resonator is to remain at its maximum intensity.
Resonators, wherein the distance between the discharge end of the jet producing means and the fluid receiving cup must be adjusted, have not been found to be satisfactory. These resonators require the provision for an adjusting means, which necessitates time consuming adjustments in order to obtain and/or maintain performance of the resonator at a desired frequency, since the desired frequency of the high-frequency sound waves often changes to an undesired frequency after continued use and or physical abuse. Accordingly, a proper adjustment of the resonator is only of short duration.
The very creation of high-frequency vibrations make it difficult to maintain a fixed position of adjustable parts as the vibrations tend to move the parts. As the vibrations are ultrasonic, special equipment was needed to make the frequency adjustments. As these resonators are used in places, such as warehouses, food processing plants and factories, the only indication of the need for readjustment was the return of the pests.
There thus remains a need for a resonator wherein each of the partsthereof is so designed that, when assembled, they are so related to each other in a manner to produce their intended functions without the need for any adjustments.
OBJECTS OF THE INVENTION One of the primary objects of the present invention is to provide a resonator that includes a member having a rigid airfoil surface so shaped that, when it is impinged by a jet of fluid, it produces an ultrasonic vibration that is so irritating to pests, e.g., rats, that they leave the region in which they encounter such ultrasonic vibrations.
Another significant object of the invention is to provide a resonator wherein a jet of fluid impinges against a member which is integral with or fastened to the resonator and produces ultrasonic vibrations of varying amplitude and of a fixed frequency that is sufiiciently irritating to the pests, resulting in their being driven away I from the region of the resonator.
Still another object of the invention is to provide a resonator in which the surface against the fluid jet impinges in order to produce ultrasonic vibrations is hard and is preshaped and integral with the body of the resonator to provide the desired tuned frequency, and requires no further shape adjustment or position adjustment in the resonator body.
A further object of the invention. is to provide a memher having an airfoil surface upon which a fluid jet impinges to produce ultrasonic vibrations wherein said member is capable of being produced integrally with the body of the resonator.
An additional object of this invention is to produce a resonator for ultrasonic vibration production which utilizes a fluid supply means that continuously supplies a stream of fluid to the jet producing means and continuously and cyclically introduces pulsation into the jet producing means to produce ultrasonic vibration which cyclically varies in amplitude at the selected frequency.
A still further object of the invention is to produce a compact selfcontained means for converting electrical energy to ultrasonic vibrations of selected frequency and continuous and cyclically varying amplitude.
BRIEF DESCRIPTION OF THE INVENTION Briefly, in accordance with the invention, the resonator produces sound waves of a frequency effective for repelling pests and comprises a housing, and a sound directing means formed in said housing, said sound directing means constituting a flared cavity therein; a first bore formed in the housing and opening into the cavity; a fluid jet producing means positioned within the first bore and projecting into the cavity; a second bore formed within the housing coaxial with the first bore; a resonator means positioned. in said second bore and linearly spaced from the jet producing means. A preformed, rigid and nondeformable air modulating foil extending into the space between the fluid jet producing means the the resonator means.
According to another embodiment of the invention, the resonator is employed in combination with a means to supply fluid to the jet producing means.
The invention will be better understood and the ob jects other than those set forth above will become apparent after consideration is given to the following detailed description which makes reference to the annexed drawings, presenting the preferred and illustrative embodiments of the invention, and wherein:
FIG. 1 is a perspective view of the ultrasonic sound producing device constructed in accordance with the present invention;
FIG. 2 is a top plan view of the ultrasonic sound producing device illustrated in FIG. 1.
FIG. 3 is a longitudinal sectional view through the ultrasonic sound producing device illustrated in FIG. 1;
FIG. 4 is an enlarged sectional view showing the rela- V FIG. 5 is a perspective view of the ultrasonic sound producing device illustrated in FIG. 1 including an air compressor constructed in accordance with the present invention; and
FIG. 6 is a longitudinal sectional view of the ultrasonic vibration producing device and air compressor illustrated in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION Referring now more specifically to the drawings, it is to be noted that the resonator device shown therein and indicated generally by the reference numeral 30 comprises a housing 32 of substantially cylindrical shape. Housing 32 may be formed of any well known, commercially available, rigid durable material and could, for example, be formed from a metal, metallic alloy or a suitable synthetic plastic resin. The housing 32 is provided with a recess 34 into which is fitted an adapter 32. The other end of the the adapter 22 is provided with screw threads which fit into an opening in the head of the compressor directly opposite to the diaphram. That portion of the adapter extending into the recess 34 includes a groove for receiving an O ring 36 in order to form a fluid tight joint. A set screw 38 can be used to secure the adapter in the recess 34. The
adaptor 22 is made so as to fit in a fixed position within the body of the resonator without any adjustment.
A fluid jet producing means or nozzle 40 having threads 42 on its exterior is mounted for axial adjustment within aid threaded recess base 34 by means of a socket 34 constructed to receive an Allen wrench or equilivent tool therein. The fluid producing member or nozzle 40 has a passage 42 extending therethrough that is in fluid communication with adapter 22.
A threaded recess base 44 positioned diametrically opposite recess 34, and in axial alignment therewith, extends inwardly from the external surface of the housing 32. A fluid jet receiving member or fluid jet obstruction means or resonator means 46 having external threads thereon, is received in threaded recess 50 and can be secured in its proper position by conventional means. Fluid jet receiving or obstruction means or resonator means 46 is provided with a cup-shaped receiving cavity 48 in its end, facing fluid jet producing means 40.
For particularly good results, the orifice of the fluid jet producing means or nozzle has a diameter of about 0.080 inches and the cup-shaped receiving cavity 48 on the fluid jet receiving member of fluid jet obstruction means has a diameter of about 0.130 inches and a depth of about 0.080 inches.
Housing 32 is preferably provided with a cylindrical space or cavity 50 into which the outlet end of fluid jet producing member or nozzle 40 and the cup end of fluid jet receiving member or resonator means 46 enter in aligned, spaced apart, relationship. Extending away from and in communication with cylindrical space or cavity 50 at one end, and in communication with the surrounding atmosphere at its other end, is a flaring sound emitting'horn 52 said cylindrical cavity and flaring sound emitting horn forming a flared cavity.
At the bottom of the cylindrical space 50, in a direction opposite to that of the horn, is an airfoil or air modulating foil 53 having a preformed shape. The outer portion of the airfoil has a first portion shaped to be engaged by the jet stream from the jet producing means 42 as the fluid jet passes in its path of travel from the nozzle of the adapter 22 to the cavity 48 in the fluid jet receiving means.
Referring, once again, to Baxter, US. Pat. No. 3,188,999, it is to be noted that one important factor that must be considered in determining the frequency of the sound waves to be emitted by a resonator is the amount of spacing that is established between the jet producing means and the cavity into which the fluid jet is received. As noted hereinbefore, resonators wherein the distance between the fluid jet producing means and the cavity of the jet receiving means is adjustable and the fluid jet passes over an adjustable or yieldable airfoil surface in its path of travel, have not been found to be satisfactory, since they require the provision of one or more adjusting means. The adjustment involves a lengthy procedure and even after proper adjustment, they are capable of retaining the proper adjustment only for periods of short duration. The provision of an integral or fixed airfoil surface and fixed jet and receiving means overcomes the abovementioned adjustment problems, as well as other problems which may arise due to possible change in the shape of the airfoil surface due to variations in the pressure which may occur in a tub such as tub 45 of the Baxter patent.
The integral airfoil 53 of this invention can be preformed at the time of making the housing and can be cast integral therewith or can be permanently secured to the housing to be substantially integral therewith in operation. According to a preferred embodiment of this invention, best results are obtained when the airfoil extends about 0.25 inches into cavity 50 and partially into the path of the jet fluid stream passing from the jet producing means 40 to the cup end 48 of the fluid jet obstructing means 46. That portion of the airfoil extending into the path of the jet fluid stream is about 0.094 inches thick.
The outer end of the horn portion of the resonator can be provided with a cover 54 to protect the device from dirt and weather.
According to another preferred embodiment of this invention, resonator 30 is employed in combination with compressor 10, forming a compact unit, and wherein this combination enables pests to be repelled from a particular environ in a more efficient and effective manner than achieved with other high-frequency devices.
The air compressor 10 is a well-known construction and is described only to the extent necessary to the understanding of the present invention. It is to be understood that details of the construction of the compressor not detailed are well known in the art.
FIG. 5 shows a longitudinal section through both the compressor unit and the resonator, and the reference numeral 2 indicates the housing of the compressor containing the stator 3 of the electric motor with the stator screws 4 holding the stator in the housing. The rotor 5 of the motor is mounted in the ball bearings 6, with the end of the housing 2 is closed by the front cover 8, which supports air filter 9 in the body 10 and the center insert 11.
The shaft of the rotor has an eccentric 12 secured thereto by the set screw 13. A connecting rod 14 having an enlarged head 15 is mounted on the bearing on the eccentric 12. The head 15 with the diaphram 16 form the expansible wall of the compressor. The periphery of the diaphram 16 is secured in an opening in the housing 2 by the head 17, which, together with the diaphram, form the chamber of the compressor. The diaphram is provided with valves 18 to control the entry of air into the compression chamber.
As noted hereinbefore, the construction thus far described represents the conventional construction of a well-known portable air compressor and which, per se, forms no part of the present invention.
Best results are obtained with the resonator of this invention when the resonator is mounted in relation to the expansible chamber compressor thereby producing ultrasonic vibrations which vary in amplitude. The present invention includes the feature of mounting an ultrasonic resonator directly upon the head of the compressor in such manner that the air passes directly, in a straight line, from the compressor or to the jet pro ducing means of the resonator, so that the inherent pulsation produced by the reciprocation of the expansible chamber of the compressor are transmitted to the jet of air and thus to the vibration.
The compressor diaphram is driven directly by the shaft of the electric motor and these pulsations are directly related to speed of the motor. in a common type of compressor the electric motor is operated at about 1,700 rpm. so that the number of cycles of the compressor is about 28 cycles per second. At this rapid rate, the effect of the pulsation would ordinarily be lost if the fluid material travels around a bend before being delivered to the resonator.
In operation of the resonator-compressor combination, electric current is supplied to the motor of the compressor, and the diaphram is reciprocated by the connecting rod and air is passed into the air chamber and through the adaptor 22 to the nozzleof the jet producing means 40 and hence over the surface of airfoil 52 into the cavity of the fluid jet receiving means 46. As in the device disclosed in the Baxter patent, referred to hereinbefore, the velocity of the fluid delivered by the fluid jet producing means 40 in passing over the airfoil surface has its velocity increased to such an extent that frequencies in excess of the audible range are delivered by the norn of the resonator, and these frequencies are effective for repelling pests, e.g., birds, rodents and insects. Since the distance between the fluid jet producing means and the jet receiving means constitutes an important factor in determining the output frequency. the resonator which is directly connected with its own compressor can be effectively designed to give the most effective frequencies.
As the resonator is mounted in direct alignment with the diaphram of the compressor and the tubing connecting the jet producing means to the compressor is short, the pulsation produced in the compressor will be transmitted to the jet producing means, thereby varying the amplitude of the ultrasonic vibrations produced. This variation in amplitude may vary over a wide range, but it has been found that a variation of at least 25 percent is desirable and it is preferred to have a variation of at least 50 percent with best results being achieved with a variation of at least about 80 percent. A vibration which varies in intensity has been found to be more effective in driving pests away than the same frequency of vibration at a constant intensity.
While it is preferred to employ the same means to produce a constant supply of air and the corresponding pulsations as shown by the device of the preferred embodiment. it is also possible to employ a separate means to produce a constant supply of air and another means to produce the pulsations at the jet.
The operation of the resonator with a compressor, such as that described above, a fluid, e.g., compressed air is supplied to the resonator at pressures of at least 1 p.s.i.g. and preferably between about 4 to 6 p.s.i.g.
Since the resonator is mounted directly upon the head of the air chamber of the compressor, the parts are held in a fixed position at all times and the resonator can be designed so that it can be mass produced and installed in remote places without requiring adjustment during the life of the device.
It is believed that it will be readily apparent from the foregoing description that a resonator constructed in the manner taught in this specification and employed in combination with a compressor wherein the ultrasonic sound waves eminating from the resonator will vary in amplitude by as much as about percent, will accomplish the objects set forth at the outset of the present specification.
What is claimed is:
l. A device for producing sound vibrations of a fre quency effective to repel pests comprising a housing member and a sound directing means formed in said housing; said sound directing means constituting a flared cavity; a first bore formed in said housing and opening into said cavity; a fluid jet producing means positioned within said first bore and projecting into said cavity; a second bore formed in said housing coaxial with said first bore; a resonator means positioned in said second bore and linearly spaced from said jet producing means; a rigid and nondeformable air modulating foil formed with said housing and extending transverse to the axis of said fluid jet producing means and resonator means; and said airfoil extending into the space between said jet producing means and said resonator means.
2. The device of claim 1 wherein said air modulating foil is preformed.
3. The device of claim 1 wherein said fluid obstruction means is provided with a jet receiving cavity.
4. The device of claim 1 which further comprises a means to continuously supply fluid to said jet producing means.
5. The device of claim 4 wherein the means for supplying fluid to said jet producing means further includes means for supplying pulsations to the fluid passing jet producing means.
6. The device of claim 1 including means for producing cyclic and continuous variations in amplitude of the vibrations.
7. The device of claim 6 wherein the means for supplyingfluid to said jet producing means includes means for pulsating the fluid delivered to the jet producing means.
8. The device of claim 7 wherein said pulsating means includes an expansible chamber air compressor.
9. The device of claim 8 wherein said resonator is mounted upon and directly connected to said air compressor.
10. The device of claim 8 wherein said resonator is mounted upon the air compressor and said jet producing means is in alignment with the expansible chamber of the compressor.
struction means extends into said cavity about 0.25 inches and is about 0.094 inches thick.
15. The device of claim 14 wherein said fluid obstruction means is provided with a jet receiving cavity having a diameter of about 0.130 inches and a depth of about 0.080 inches and said fluid jet producing means is provided with an orifice having a diameter of about 0.080 inches.