US1131636A - Mechanical horn. - Google Patents

Description

M. R. HUTGHISON. MECHANICAL HORN.

APPLICATION FILED MAR. 1, 1913. 1 131,636 Patented Mani), 1915.

2 SHEETSSHEET 1.

ATTORNEYS M. R. HUTCHISON.

' MECHANICAL HORN.

APPLICATION FILED MAR. 1, 15:13.

1,131,636. Patented Mar. 9, 1915.

2 SHEETS-SHEET 2.

WITNESSES g 4; @vLmTTOH/VEVS .DfiSTATES PATENT OFFICE.

MILLER. REESE Horomson', 61 WEST ORANGE, NEW JERSEY, ASSIG-NOR T Lov LL- MoGONNELL MANUFACTURING COMPANY, A CORPORATION or DELAWARE.

MECHANICAL HORN.

' Specification of Letters Patent.

Patented Mar. 9, 1915.

Application filed March 1, 1918. Serial No. 751,481.

ments in ,MechanicalI-Iorns, .of which the following is a specification.

In my Patent No. 923,049, issued May 25th, 1909, and in my Patent No. 883,643, issued March 31st, 1908,-I have described the various preferred constructions and operations of a horn wherein the sound is caused by operation of the rotary cam upon an elastic diaphragm. I have also explained certain desirable features of the cam and of a cooperating thrust member or anvil on the diaphragm, whereby I sought toja'void Such lateral tilting of the contact piece and reverse bending of the diaphragm as is disclosed in the Bapst and Falize Patent 384,412, granted June 12th, 1888. In my Patent No. 923,048, issued May 25th, 1909, I show and describe, but do not claim, a horn or resonator and a diaphragm, in combination with a rotary memberhaving an eccentric thrust surface, a thrust member driven by said eccentric'surface, a guide for. confining the motion of said thrust member to a direction perpendicular to the diaphragm, and means for rotating said rotary member sons to displace said thrust memher at rates corresponding to the frequency of desired notes to be produced. Y

My present invention relates to devices of the above type and the present application is a division'of my prior application, Serial No. 494,688 filed May 7th, 1909, and copending with the applications of, Patents Nos. 923,048 and 923,049 above referred to.

My present invention particularly involves the use of a thrust member independent of the diaphragm and preferably free to rotate in respect thereto and about its own axis and held inposition by a guide which prevents movement of the thrust member except about its own axis or toward and from the diaphragm. The thrust'of the cam is thus transmitted to the diaphragm /through an intermediate thrust member 7 which is not fixed to the diaphragm, but

which is suitably guided, so as to prevent lateral movement of itself and to prevent lateral movements of the diaphragm or tilting stresses in the latter.

- Another feature of my invention consists in so shaping thethrust member that it is impossible for it to bind or become caught in the guide.

Reference is to be had to the accompanying drawings in which similar reference characters indicate corresponding parts throughout the several views.

:Figure 1 is a vertical section showing one embodiment of the invention as applied to an alarm or signaling device of the general construction employed in the commercialKlaxon horn. Fig. 2 is a transverse section taken substantially on the line 22 of Fig. 1; and Figs. 3, 4, 5 and 6 are details showing modified forms of thrust members and supports therefor.

My present invention is applicable to horns or signaling devices varying widely in detail from that illustrated as will be apparent from a consideration of the appended claims. In this specific form the diaphragm 1 is clamped at the edges between two sections of an inclosing case, the rear section 2 of which is-formed with rear walls approximately parallel with the diaphragm, except where it is enlarged, as at 3 and 4, to form inclosing chambers for-the cam, cam shaft, and bearings. The front cover or resonator section 6 of thediaphragm case is shown as being substantially parallel with the diaphragm and far enough away from it to permit maximum vibration of the diaphragm without engagement with the case and has a central opening 7 of large diameter so as to expose a large portion of the effectively vibrating part of the diaphragm. The opening is surrounded by an annular flange 8. The resonator 10 is secured to this flange preferably by spinning the material against the outer wall thereof or by brazing or by both. The periphery of the front section 6 is formed with a flange 11 fitted over the rear section 2 of the diaphragm case. As shown in the drawings the clamping surfaces are of ample Width and thickness to apply the clamping pressure of the screws 12 evenly about the periphery of the diaphragm. The qualitv of the note is improved and destructive vibration and cutaction of the diaphragm is prevented by washers 13 and 14 arranged between the diaphragm and the clamping faces of each section of the case. These washers may be of non-vibratory material, such as cork, Wood, or hardened fiber.

The diaphragm 1 is shown as be1ng pro vided with a wear-piece 15 formed with a shank 16 riveted over a washer 17. Th1 s wear-piece operates to receive the thrusts from the thrust member as movement 1s rmparted to the latter by the cam.

The section 2 of the diaphragm case is shown as being formed with webs 18, 19, having alined cam shaft 20. The latter is mounted in a bearing sleeve 21 with its axis eccentric to but preferably parallel with the axis of said hearing 21, as shown more clearly in Fig. 2. When said bearing is rotated, the axis of the shaft moves in a circular path approximately parallel with the axis of the sleeve. In practice I find that the radius of this eccentricity need not be much greater than the. amplitude of vibration of the diaphragm, in order to give a throw amply sufficient for all required adjustments of the power shaft without respect to the diaphragm.

The sleeve bearing 21 is held in a desired position of longitudinal adjustment by means of the screw collar 22 engaging the end wall of the casing. This collar is locked in position by means of a screw key 23,

v screw threaded into collar 22 and having a stud engaging a recess in sleeve 21. There is a cooperating lock nut 25 outside of the casing which may be loosened to permit rotary adjustment of the sleeve bearing 21 and the cam shaft 20 carried thereby and which may be tightened to rigidly clamp saidbearing against both longitudinal and rotary movement.

The power shaft 20 is operatively arranged to vibrate the diaphragm preferably through the medium of a rotary member 26, having eccentric surfaces adapted to apply the power of the shaft to displace the thrust member which in turn displaces the diaphragm to cause the desired vibratory movements thereof. The eccentric surfaces on the rotary member, as shown, are peripherally arranged cam surfaces, though it is obvious that I may use other equivalent eccentric surfaces. The rotary member or cam 26 is rigidly secured to the cam shaft 20 in any desired way and is prevented from endwise displacement therefrom by lock nuts 29. The motor on the power shaft 20 'is free to vary its speed in proportion to the work done and is capable ofdriving the cam at such speed as to give the diaphragm its harmonious natural frequency of vibration.

Oil for lubricating the shaft 20 and also the contact between cam 26, wear-piece 15 openings for support of the upon by the cam. The motor. is free to va its elasticity and inertia. The thrust memin the form of a and the thrust member is supplied through an oil passage or reservoir 30. -Part of the oil is thrown by centrifugal force from the rapidly revolving cam against the thrust member.

My invention as applied to the above construction, includes a' thrust member 31' separate from the diaphragm and lateral guides 70, 70, on both sides of the thrust member to position the latter. The thrustmember is preferably separate and independent of the guides and is also unattached to the diaphragm and capable of bodily movement an oil passage or-reservoir 30. Part of the toward and from the diaphragm. Preferably it presents a curved contour or peripheral surface, and is free to rotate about its own axis. -The thrust member is of such diameter and the cam is of such shape and so located in respect thereto and to the diaphragm, that the diaphragm is positively forced by the thrust member a slight distance beyond its normal plane and while said thrust member is being directly acted its speed in proportion to the and upon high speed rotation the diaphragm is forced by harmonious positively and rigidly applied thrusts of the cam through the thrust member to a predetermined distance beyond normal and is permitted to swing freely a desired distance beyond the forcing movement according to its own natural movement as determined by work -done,

her is preferably of hardened steel and either cylinder or in the form of a ball, the one having the advantage of line contact and distributed application of power and wear, whereas the other has point contact and less mass and less momentum.-

The guides are formed as part of a bridge piece 71 secured to the face of the. casing by screws 72, 72, and provision for adjustment of the position of the guide is made 1 by having the holes 74 somewhat larger than the shanks of the screws 72. The vertical surfaces of the guides 7O and the amount of projection of the anvil or wear-piece from the diaphragm, are so proportioned that the 1 latter may vibrate freely without danger of striking the guides. The guides and adjacent portions of the supporting bridge piece are preferably cutaway, as at 76, 75, to. permit necessary adjustment of the cam, 1 without danger of contact with the guide or guide supports.

In order to prevent the thrust member from possibility of the striking or becoming jammed in the guide, the faces of the thrust member presented in the direction of reta tion of the cam, in case said member is not rotatable, are curved and the ends of the thrust memberare'preferably out along the surfaces of of tlie cam a cylinder having. an axis pass- T ing throu h the axis of thadiaphragm. Thus the %hrust. member has line or point contact with the guide instead of surface contact, the essential being that the sides and ends of the thrust member fit the gu de through the limited range of angular displacement which is likely to occur during vibrations of the diaphragm.

In Figs. 1 and 2 I have shown the cylindrical rotatable thrust member with its ends curved. It is not essential that the ends of the thrust member be curved as the edges may be merely rounded as indicated in Fi 3. In this Fig. 3 I have shown a cylin or 110 with rounded edges mounted in a uide 10& the opposite walls of which are s ightly convex. This cylindrical body may be bored as at 111 and may be made as a tube of spring steel;

In Fi s. i and 5, the diaphragm is shown as provided with a wear-piece 100 and a spherical thrust member 101 is interposed betweenit and the cam. The guides 102 hold the sphere in position against displacement except in the direction of vibration of the diaphragm. A convenient arrangement for this guide is illustrated in Fig. 4 where the cylindrical ends of the guides 102 are rigidly connected by side bars 103 secured thereto by screws 104;. The guides need not have the uiding flanges 70 as indicated in.

Figs. 1 an 2 as a small aperture in the guide is sufficient if the range of movement of the thrust member be comparatively small. In Fig. 6,'I have shown a thrust member in the form of a cylinder 76 having rounded ends 77 and merely placed in an aperture in a bar 78 constituting the bridge piece or guide. Here the walls of the guide passage are straight instead of being convex as'in Fig. 3 or concave as in Fig. 4.

It will be noted that the thrust member is free to rotate about its own axis, thus as the cam in moving across one side of the thrust member tends to rotate the thrust member the wear will be distributed and for each thrust by the cam a new surface will be presented. Furthermore, the turning of the thrust member reduces the wear both at the point of engagement of the cam with the wear-piece and at the point or line of engagement between the thrust member and the wear-piece. The thrust member acts to positively transmit the force of the cam to the diaphragm and to give the latter a partly forced and partly free movement, instead of being projected from the cam toward the diaphragm to cause the latter to vibrate by the force of the blow delivered fromthe thrust member. This latter operation is not ordinarily desirable as in such construction the force of the blow is dependent solely upon the mass and speed of the thrust member rather than upon the power applied to the cam and there is less automatic governing of the speed of the motor.

Having thus described my invention, what I claim as new and desire to protect by Letters-Patent is i .1. In an alarm or signaling device of the class described, a horn or resonator and a diaphragm in combination with a rotor having a plurality of cam projections spaced apart and means for rotating it at high eed e pe Qt r ta i an o fi retion of the cam projections being such as to mechanicallyand positively force outward movement of the diaphragm at such velocity as to cause further outward movement of the diaphragm in the same direction by momentum against increasing elastic stress and to, permit free inward movement of the diaphragm to, a predetermined distance on the other side of normal, a thrust member intermediate of said rotor and said diaphragm and unattached to. the latter and driven by the cams, and a guide for said thrust mem- 2. In an alarm or signaling apparatus of the class described, a horn or resonator and a diaphragm in combination with a rotary cam, a thrust member actuated by said cam and a support for confining the bodily motion of said thrust member to a direction perpendicular to the diaphragm, said thrust member being rotatable about an axis parallel to said diaphragm and having opposed curved bearing surfaces in engagement with the surfaces of the support.

3. In a device of the class described, a motor free to vary its speed in proportion to the work done, a rotary cam mounted on the motor shaft, an elastic diaphragm having a natural frequency of vibration, a ball intertoo slight distance beyond its normal plane, 7

whereby upon high speed rotation of said cam said diaphragm is forced by harmonious positively and rigidly applied thrusts of the cam through the ball to a predetermined distance beyond normal and is permitted to swing freely a desired distance beyond the forcing movement, according to its own natural movement as determined by its elasticity and inertia and said ball being free to rotate about an axis parallel to said diaphragm as said cam engages with and passes the same. 4. In an alarm signal of the character described, a diaphragm, a plurality of cams, a rotatable carrier for said'cams, an intermediate thrust transmitter arranged between said cams and said diaphragm, and simultaneously contacting with said diaphragm and I member said diaphragm While being one of said cams to forcibly displace said diaphragm, and a support for said interme diate thrust transmitter independent of said diaphragm, said thrust transmitter being in the form of a steel ball free to rotate.

5. In an alarm signal of the character described, a diaphragm, a rotatable member presenting a series of cam surfaces, an intermediate thrust transmitter arranged between said cam surfaces and said diaphragm, and simultaneously contacting with said diaphragm and one of said cams to forcibly displace said diaphragm, and a support for said intermediate thrust transmitter independent of the diaphragm, said thrust transmitter being free to rotate about its ownaxis.

6. In an alarm or signaling apparatus of the class described, a horn or resonator and a diaphragm, in combination with a rotary member having spaced cam projections, a thrust member unattached to said diaphragm and adapted to forcibly displace said diaphragm While being forced by said cam projections and to enter between said projections upon the reverse vibration of said diaphragm, and a guide having a passage for confining the motion of said thrust to a direction perpendicular to the diaphragm, said thrust member being formed with lateral bearing surfaces curved about an axis parallel to said diaphragm for engagement With the Walls of said guide passage. j

7. In an alarm or signaling apparatus of the class described, a horn or resonator and a diaphragm, in combination with a rotary member having spaced cam projections, a thrust member adapted to forcibly displace forced by said cam projections and to enter between said projections upon the reverse vibration of said diaphragm, and a guide having a passage for confining the motion of said thrust member to a direction perpendicular to the diaphragm, said thrust member being rotatable about an axis parallel to said diaphragm to permit the lateral movement of the surface of said thrust member farthest from said diaphragm as the cam projections engage with and pass said surface.

In an alarm or signaling device" of the class described, a diaphragm, a rotor, and means for driving the latter in combination with a rolling contact thrust member, and means for rotatably holding said member in a normal position in the line of thrust between said rotor and diaphragm.

9. An alarm or signal having a rotor having a contour adapting it to exert thrust, a diaphragm, a rolling contact member interposed as a thrust member between the rotor and diaphragm and having a normal position therebetween, and means for preventing displacement of the member without preventing rotation thereof.

10. An alarm or signal having a diaphragm and cam in combination With a rolling contact member having a normal position therebetween and acting as a thrust member, and means for rotatably holding it at the center of the diaphragm and in operative relation to said cam.

11. A mechanical horn embodying therein a flexible diaphragm, a Wear-piece rigidly secured thereto at the center thereof, a diaphragm casing member having its peripheral portion held rigid in respect to the peripheral portion of the diaphragm, a guide member rigidly secured thereto and having a portion disposed adjacent to but spaced from said earpiece, said portion having an aperture substantially in axial alinement With said Wear-piece, a drive shaft projecting through said casing member, a rotor carried by said drive shaft and presenting a series of spaced ;projections, and

a thrust member disposedwithin said aperture and rotatable about its own center and serving to engage with said Wear-piece and repeatedly forcibly displace said diaphragm upon the rotation of said rotor.

12. A mechanical horn'embodying therein a flexible diaphragm, a frame member held rigid in respect to the peripheral portion of the diaphragm and having a portion adjacent to but spaced from the center of said diaphragm and having an aperture in axial alinement with said diaphragm, a thrust member rotatable about an axis parallel to said diaphragm within said aperture and guided in a direction substantially at right angles to said diaphragm, and a rotor having a series of projections adapted to successively engage with said thrust member and forcibly displace said diaphragm.

Signed at West Orange Essex and State of New Jersey this twentyseventh day of February A. D. 1912.

C. W. FAIRBANK, FLORENCE LEVIEN.

Copies-0f this patent may be obtained-for five cents each, by addressing the Commissioner of Patents,

Washington, D. G.

in the county of-

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