US3182307A

US3182307A - Electrical signalling devices

Info

Publication number: US3182307A
Application number: US92226A
Authority: US
Inventors: Doggart John
Original assignee: V&E Friedland Ltd
Current assignee: V&E Friedland Ltd
Priority date: 1960-02-29
Filing date: 1961-02-28
Publication date: 1965-05-04
Anticipated expiration: 1982-05-04

Description

y 1965 ,1. DOGGART 3,182,307

ELECTRICAL S IGNALLING DEVI CES Filed Feb. 28, 1961 IN l/EN 70B Jb/m/ DOGGAET United States Patent O 3,182,307 ELECTRICAL SIGNALLING DEVICES John Doggart, Macclesfield, England, assignor to V. 8; E.

Friedland Limited, Macclesfield, England, a British company Filed Feb. 28, 1961, Ser. No. 92,226 Claims priority, application Great Britain Feb. 29, 1960 2 Claims. (Cl. 340-492) This invention relates to electrical signalling devices.

According to one aspect of the invention there is provided for an electrical signalling device, a coil unit comprising a coil having projections at each end thereof and a mounting comprising a base, two spaced resilient arms upstanding from the base and resiliently and releasably gripping the coil, and a socket in each arm, respectively receiving the projections to locate the coil between the arms. In this way the coil may be easily and speedily assembled on its mounting which itself may be arranged for relatively simple assembly in the signalling device.

The mounting may be formed from a metal sheet and the two arms may be provided by spaced portions of the sheet which have been deformed out of the plane of the sheet to lie in parallel planes substantially perpendicular to the plane of the sheet.

According to another aspect of the invention there is provided for an electrical signalling device, the combination of a coilunit as set out in either of the preceding paragraphs with a striker and a sound emitting member, preferably a tone bar, which emits a sound on being struck by the striker, the sound emitting member being carried by the said mounting, and the striker being movable by the coil to strike the sound emitting member.

According to yet a further aspect of the invention there is provided an electrical signalling device comprising the combination as set out in the preceding paragraph further comprising a housing encasing the said combination and having at least one sound aperture through the wall of the casing and aligned with the tone bar, the said combination being located within the housing so that in use the vibrations of the tone bar, or at least its major vibrations, take place in a direction towards and away from the aperture. Preferably the tone bar is mounted so that it has at least two antinodes when set into vibration and the casing has two apertures aligned, as aforesaid, with the antinodes.

One embodiment of the invention, which is a so-called door-chime will now be described by way of example with reference to the accompanying drawings. In the drawings:

FIGURE 1 is an underplan View, partly in section of a door chime embodying the invention;

FIGURE 2 is a perspective view of a mounting for the coil unit of the door chime of FIGURE 1; and

FIGURE 3 is a side view of the door chime of FIG- URE 1.

Referring now to the drawings, the chimes comprise a housing 11 formed in two parts, a hollow generally rectangular shaped cover or casing 12 and a flat back plate (not shown) which is a close fit in the open side of the cover 12. The longitudinal sides 14 of the cover are slightly bowed outwardly to provide a pleasing appearance. The top or front of the cover is formed with five bands of narrow grooves 15 separated by raised fiat strips 16 and the ends 17 of the casing are fiat but are provided with outwardly-extending flanges 18 at their lower edges to enable the housing 11 to be fixed to a wall or other surface. The cover 12 is moulded in plastic material.

The

tone bars

19 and 29 and the striker assembly 21 are mounted within the casing 12 on a mounting unit 22. The mounting unit 22 is formed from a sheet of ferromagnetic material and comprising a generally square cen- Patented May 4-, 1365 tral portion 23 and four L.-shaped arm portions 24. When the sheet is flat the arm portions 24 extend outwardly from two opposite sides 25 of the central portion 23 of the sheet at the corners thereof so that one limb 26 of each arm 24 extends parallel to the other sides 27 of the sheet and the other or free limb 28 of each arm 24 extends parallel to the first said sides 25 of the central portion 23 of the sheet. The free limbs 28 are each formed with a constricted portion 29 adjacent their free ends. The arms 24 are pressed out of the plane of the sheet to lie in parallel planes perpendicular thereto and are braced by triangular sectioned portions 36 of the arms 24 which are deformed out of the plane of the arms 24 to give the arms a degree of rigidity. Four frusto-conical shaped depressions 31 are formed in the central portion 23 of the sheet and seat on small stubs (not shown) provided on the inner face 32 of the cover 12. The sheet 22 is secured to the cover 12 by two screws 33 threaded into two diametrically opposed stubs.

A semi-circular ended elongated arm 34 outstands from one of the sides 27 of the central portion 23 of the plate 22 centrally in the length thereof and is deformed upwardly out of the plane of the sheet 22 to lie in a plane at right angles thereto. A similar arm 35 is pressed out of the central portion 23 of the sheet to lie in a plane parallel to and spaced from the first arm 34. The first arm 34 has a circular aperture 36 through it and the second arm has an open-ended slot 37 formed in it. The slot 37 extends axially into the arm 35 from the end thereof and decreases in width intermediate its length to form a part-circular seating 38 of greater than 180 angular extent. The sides of the slot above the seating 38 converge slightly towards each other and the sides 39 of the slot below the seating 38 are parallel and closely adjacent one another. The two arms 34 and 35 provide a holder for the operating coil 41 of the chimes. The coil 41 is energised through two screw connectors 42 housed in one of the end flanges 18 of the cover 12 and which are connected to the ends of the coil 41 by wires 43.

The coil 41 closely encircles a brass tube 44 which is slightly longer than the coil 41. The external diameter of the tube 44 is such that it is a fit in the aperture 36 in the arm 34 and in the portion of the slot 37 in the other arm 35 above the seating 38. To mount the coil 41 in its mounting unit 22, the coil 41 is held above the unit 22 so that the brass tube 44 overlies the aperture 36 and the slot 37. The coil 41 is then moved downwardly into the space between the arms 34 and 35 so that one end 45 of the tube 44 slides against the inner surface of the arm 34 and the end face of the coil 46 adjacent the other end 47 of the tube 44 slides against the inner surface of the other arm 35. The end 47 of the tube 44 passes along the slot 37 in the arm 35. The axial length of the coil 41 is substantially equal to the normal spacing of the arms 34- and 35 and consequently the two arms 34 and 35 are slightly forced apart when the coil 41 and core 44 are passed into the space between them. The coil 41 and core 44 are pushed into the holder until the end 45 of the tube 44 registers with the aperture 36. The arms 34 and 35 are then no longer forced apart and come in towards each other under their own resilience. The end 45 of the tube 44 then passes through the aperture 36. When the coil 41 is inserted into the mounting unit 22 there is a click as the end 45 of the tube 44 engages in the aperture 36.

In this example, the

tone bars

19 and 29 comprise two rectangular sectioned strips of metal and are cadmium plated. Each strip is about 5 /2 inches long, 1 inch in width and is provided with two apertures 48 (only one shown) spaced respectively about 1 /8 inches and 1% inches from the ends thereof. The

bars

19 and 20 are mounted between the flanges 49 of flanged rubber bushes 51 threaded on to the constricted portions 29 of the arms 24. The axial length of the bush 51 between the flanges i 49 is greater than the thickness of the bars 19 and 2t) and the diameter of the bar apertures 48 are greater than the external diameter of the bushes 51' between the flanges 4h.

. Consequently, the tone bars can move relative to the The bars 19, 2t! are set into vibration by a striker unit 21. This unit 21 comprises a thick-walled soft iron plunger 52 which is a sliding fit in the core 44 of the coil 41. Two short plastic (cg. nylon) striker rods 53 and 54 are inserted in blind axial bores in the ends of the plunger 52 and project from each end thereof. plunger 52 is encircled by a light compression spring 55 which acts between the arm 35 and a spring washer 56 engaging the striker rod- 54 adjacent one end thereof. In its extended condition, the spring 55 maintains that end of the striker rod 54 slightly spaced from the adjacent tone bar 20.

Four similar rectangular apertures 57 are formed through the sides of the casing .12, two in each side, each aperture being aligned withan end of a

tone bar

19 or 20. Each aperture 57 extends for substantially the whole Width of the tone bar 19 and and extends along the length of the tone bar from an end thereof to adjacent a bush 51 on which it is mounted. In this example, the apertures taper in Width from about A; of an inch to about of an inch adjacent the back 32 of the cover 12 and are about of an inch long.

When the coil 41 is energised, the plunger 52 is drawn rapidly into the coil 41 causing an end of the nylon striker rod 53' to strike against one of the tone bars 19. That bar 19 is therefore caused to vibrate, nodes occurring at the positions at which the bar 19 is mounted. When the coil 41 is de-energised, the plunger 52 is moved rapidly in the opposite direction by its encircling spring .55 and strikes against the other tone bar 29. That bar 2%) is therefore also caused to vibrate, again nodes occur at the positions at which the bar 20 is mounted. The two tone bars 19 and 20 are struck approximately centrally and sub.- stantially perpendicular to their length. Consequently the principal or major vibrations set up in each tone bar occur in a plane perpendicular to the longitudinal axial plane of the tone bar. The plane in which the major vibra- The tions, occur is therefore substantially perpendicular to the appropriate aperture 57 and consequently the major vibrations take place in a direction towards and away from the aperture. The mounting unit completes the magnetic circuit of the coil and plunger mechanism.

I'E'Wlll be noted that-the door chime does nothave any separate resonating chambers or tubes. The function of these resonating chambers or tubes is fulfilled by the easing 12 which is tuned as near as possible to the frequencies of the two tone bars 19 and 20 to give the maximum dura- 60 tion of resonance of these bars. While this must, of course, be a compromise, I have found that the duration 4 i of resonance is only slightly less than that achieved with separate resonating chambers or tubes.

It will also be appreciated that the assembly of the various parts on the mounting unit 22 can be readily and speedily effected. Similarly the mounting unit 22 can be readily and speedily attached to the cover 12 to complete assembly of the door chime.

The invention is not restricted to the details of the foregoing example. For instance, any number of apertures may be formed through thecover of the chime.

I claim:

1. For an electrical signalling device the combination of:

(a). a striker mechanism,

(b) a tone barhaving'sup'port openings therethrough,

(c) a mounting having a base part,

(d) a pair of spaced resilient arms'upstandingfrom the base part and releasably and resiliently gripping the striker mechanism, I

(e) a further pair of resilient arms upstanding from the base part and having at their free endsparts which extend in a direction parallel to the base part, the'said parts having constrictions. along their length, and

(f) resilient grommets surrounding the said constrictions and passing through'the support. apertures. to support the tone bar on the said further arms.

2. An electrical signalling device, comprising:

(a) a ferro-magnetic support member,

(b) a pair of tone oars,

(c) a striker mechanism including a plunger armature and a solenoid coil Wound onto anon-magnetic tube,

(d) three pairs of arms pressed out of and integral with the support member, two pairs of said arms being located at opposite sides of the support member and each releasably supporting one of said tone bars intermediate the opposite ends thereof, and the third pair of said armsresiliently and releasably gripping said coil at a position between saiditone bars, there being a low reluctance path between saidv third pair of arms, and

(e) a casing comprising a flat cover part and four surrounding side parts projecting therefrom, the support member being secured to the flat cover part within the side parts and with the tone bars and striker mechanism within the said side parts, said casing having sound apertures opposite the antinodes of maximum vibration at the ends of the tone bars.

References Cited by the Examiner V UNITED STATES PATENTS 1,307,467

NEIL C. READ, Primary Examiner. RUDOLPH V. ROLINEC, Examiner.

Claims

2. AN ELECTRICAL SIGNALLING DEVICE, COMPRISING: (A) A FERRO-MAGNETIC SUPPORT MEMBER, (B) A PAIR OF TONE BARS, (A) A SRIKER MECHANISM INCLUDING A PLUNGER ARMATURE AND A SOLENOID COIL WOUND ONTO A NON-MAGNETIC TUBE,