Electric bell construction

Dec. 22, 1970 w. l. jenkins 3,550,118

ELECTRIC BELL CONSTRUCTION

Filed May 20, 1966 3 Sheets-Sheet 1

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ATTORNEYS

Dec. 22, 1970 w. l. jenkins 3,550,118

ELECTRIC BELL CONSTRUCTION

Filed May 20, 1966 3 Sheets-Sheet 2

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INVENTOR.

WencbellL. tfenkitts BY &amp; /&amp;&amp;&amp; ATTORNEYS

Dec. 22, 1970 w. l. jenkins 3,550,118

ELECTRIC BELL CONSTRUCTION

Filed May 20. 1966 3 Sheets-Sheet 3

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INVENTOR.

WeHdeU/L.Jeitkviil·

BY attorneys

United States Patent Office

3,550,118

Patented Dec. 22, 1970

3,550,118 ELECTRIC BELL CONSTRUCTION

Wendell L. Jenkins, Canton, Ohio, assignor to The W. L. Jenkins Company, Canton, Ohio, a corporation of Ohio ⁵

Filed May 20,1966, Ser. No. 551,691

Int. Cl. G08b 3/00

U.S. Cl. 340—396 11 Claims

ABSTRACT OF THE DISCLOSURE

Electric bell construction having a bell housing, a motor structure and striker mounted within the housing, a gong shell mounted on the housing for engagement by the striker tip, and means for supplying electric power to ¹operate the striker. The housing includes a pair of integrally formed upstanding post members, the post members including grooves for receiving a magnet, a coil bobbin, and clamp means which are attatched to the posts for retaining the coil, striker and magnet in place in the housing.

This invention relates to electric bells, and more particularly the invention relates to an improved housing 25 and striker and motor assembly mounting construction for an electric bell designed to operate in response to alternating current.

Electric bell constructions are of two 'general types, one type being designed to operate in response to alternating 30 current, and the other type being designed to operate in response to direct current. Alternating current type bells, usually called AC bells, normally include a bell housing havirig a cavity which contains a motor structure. A gong shell, generally cup-shaped, is normally mounted on the 35 exterior of the housing, and a striker, mounted in the housing, is located in a position to strike the periphery of the gong shell to create the ring.

The motor structure of these electric bells includes, generally speaking, a coil, a magnet, and a ferrous material 40 moving member, a part of the striker, which vibrates in response to current passing through the coil. Such motor structures do not necessarily need to include a magnet, but magnets are commonly used to aid the magnetic field established by current passing through the coil. The fer- 45 rous moving member will be attracted first in one direction and then in the other because of the continuously changing magnetic field established because of the continuously changing current direction alternation.

Prior AC bell constructions have incorporated a multi- 50 plicity of parts for mounting the ma'gnet and the coil within the bell housing. Such parts have included a base assembly formed from stamped sheet metal, a pair of stamped sheet metal pole pieces, members to retain and hold the magnet in place, and mounting members for 55 the striker assembly.

Such electric bell constructions have been extremely difficult to assemble in the past, primarily because of the multiplicity of parts concerned. Further, since a magnet is normally incorporated in AC bell constructions and 60 because most of the mounting members are constructed of iron or steel, the assembly problem is more difficult since the magnet will tend to attract the iron and steel parts. It should, therefore, be obvious that holding the iron and steel parts in position for proper assembly is difficult 65 because of the tendency of the magnet to pull these various parts away from the intended assembled position.

Other problems and disadvantages are associated with this type of construction. For example, because of the large number of parts involved, it is necessary to provide 70 the tooling necessary to produce such parts, each of which is different from the other. Furthermore, many bell constructions require left-hand and right-hand parts which thereby add to the tooling requirements.

A still further disadvantage is inherent in such constructions because screws are normally used for assembly, with a large number required. These bells are by their nature relatively small in size and the screws are correspondingly small. However, the operating bell assembly is subjected to substantial vibration caused by the vibrating striker assembly. Thus, with a large number of parts, all of which are screwed together, it can be seen that the bell motor assembly may tend to become very loose and ultimately come apart rather rapidly, even though lock washers may be used.

These problems are compounded when considering the fact that most bell manufacturers in addition to manufacturirig AC bells also manufacture DC bells. Therefore, a complete new set of parts is necessary for the DC bells, as the large number of parts involved with the AC bells is normally not suited for use in DC bell constructions.

It is, therefore, a primary object of the present invention to provide an electric bell construction which is manufactured from considerably fewer parts than those known in the prior art. Other objectives of the invention include the provision of a unitary die cast housing assembly which has provisions for mounting a magnet, the coil, the striker assembly of the usual AC bell construction; the provision of integral features for mounting the electrical equipment necessary to operate the bell; the provision of unique mounting means for attaching the bell construction to the desired use location; the provision of parts for assembling the bell construction which may be used for both an AC bell and a DC bell, and the provision of an electric bell construction which can be manufactured and assembled with relatively simple assembly procedures.

These and other objects are accomplished by the parts, construction, arrangements, and combinations comprising the present invention, preferred embodiments of which—illustrative of the best mode in which applicant has contemplated applying the principles—are set forth in the following description and illustrated in the accompanying drawings, and which are particularly and distinctly pointed out and set forth in the appended claims forming a part hereof.

In general terms, the electric bell construction of the present invention includes a bell housing, a motor structure and striker assembly mounted within the housing, a gong shell mounted on the housing exterior with its periphery located adjacent to the striker tip, support plate means for enclosing the housing, and a male and female electrical plug assembly for supplying electric power to the coil to operate the striker. The housing of the bell construction of the present invention includes a pair of upstanding post-like members extending rearwardly from the front wall of the housing. The upstanding posts together with a pair of boss-like members provide a cavity means for receiving a magnet. The upright post members also include grooves for receiving a bobbin upon which the motor structure coil is wound. A pair of generally U-shaped clamping members is also provided to retain the striker and coil and magnet within the housing.

By way of example, the embodiments of the improved electric bell construction of the present invention are illustrated in the accompanying drawings forming a part hereof, in which similar numerals indicate similar parts throughout the various figures, and in which:

FIG. 1 is a fragmentary front elevation of an electric bell construction of the present invention, with a portion of the bell gong shell broken away;

FIG. 2 is a vertical cross section with the coil and

3,550,118 striker assembly in elevation of the electric bell of FIG. 1 taken along the lines 2—2 in FIG. 1;

FIG. 3 is a rear elevation of a bell housing showing the magnet cavity and the upstanding posts which comprise portions of the present invention;

FIG. 4 is a fragmentary rear elevation, similar to FIG. 3, with the coil striker and clamping members assembled in place;

FIG. 5 is a cross section through the housing posts and taken along the lines 5—5 in FIG. 4;

FIG. 6 is a fragmentary rear elevation similar to FIGS. 3 and 4 but showing the female electrical plug mounted on the housing posts;

FIG. 7 is a vertical cross section with the female plug in elevation taken along the lines 7—7 FIG. 6;

FIG. 8 is a cross section, partly in elevation, showing the striker assembly of the electric bell of the present invention;

FIG. 9 is an exploded perspective view showing the various parts and their relationship in the assembled condition; and

FIG. 10 is a rear elevation of the electric bell construction of the present invention showing the rear mounting plate and the male electric plug assembly.

Referring specifically to the drawings, the electric bell construction of the present invention includes a gong shell 20 which is generally cup-shaped in configuration and is very similar to the normal gong shell used in the prior art. Gong shell 20 is mounted on a housing generally indicated by reference numeral 21, by a screw or bolt 22 which may be threadably engaged in a pedestal 23 that is an integral part of housing 21. Housing 21 includes a front wall portion 24, first opposite side walls 25, curved end walls 26, an intermediate wall 27, and a mounting flange portion 28 which extends outwardly and may include a rearwardly extending portion 29, that may extend around the periphery of the housing. Front wall 24, side walls and end walls 25 and 26, intermediate wall 27 and mounting flange portion 28 define a cavity in which the motor structure and striker assembly of the electric bell construction of the present invention may be mounted.

The housing of the present invention also includes a pair of upstanding rearwardly extending post members 30. Post members 30 extend from front wall 24 in a direction toward the rear mounting flange 28, and are each provided with a deep groove 31 and a pair of shallower grooves 32. A pair of boss-like members 33 are also formed as a part of front wall 24 and are located in a position opposite from one another and aligned with the shallower grooves 32. The two pairs of grooves 32, and the pair of bosses 33 define a cavity for the receipt of a magnet, to be discussed more in detail below.

A notch or slot 34 is formed in the outer or rear face 35 of the posts 30 and extends inwardly toward front wall 24. Post members 30 each have a hole 36 formed therethrough which is adapted to receive the striker assembly, generally indicated at 37, which forms a part of the electric bell construction of the present invention.

The motor structure of the electric bell of the present invention includes a magnet 54, a coil generally indicated by 39 which includes a bobbin 40 and windings 41. A pair of lead-in wires 42 are connected to each end of windings 41 to supply current to the coil assembly 39.

Referring specifically to FIG. 8, striker 37 includes an outer tubular member 43, a core member 44 having a larger diameter portion 45, and a smaller diameter portion 46 which extends within the interior of tubular member 43. A shoulder 47 is defined by the juncture between the larger diameter portion 45 and smaller diameter portion 46. The striker also includes a striker body 48 which has a striker tip 49 attached thereto. Striker body 48 is formed of a ferrous or other paramagnetic material while striker tip 49 is formed of some non-magnetic material such as brass. The outer diameter of body member 48 is slightly smaller than the internal diameter of tubular member 43 and is freely slidable therein. However, the end 50 of striker tube 43 is belled inwardly to confine the striker body within the interior of the tube while providing a hole 51 through which striker tip 49 projects. The striker tube also includes a spring member 52 which is supported at one end on shoulder 47 and at the other end by the end of striker body member 48. Core member 44 of the striker is provided with a groove around larger diameter portion 45 and is inserted in the end of the striker opposite bell end 50. A portion of the tube 43 may be collapsed to seat in grove 53. This construction will firmly lock core member 44 in the striker tube 43.

In general terms, the operation of the striker is generally as follows. The ferrous or paramagnetic striker body 48 is located within the continuously alternating magnetic field which is set up by the alternating current. For a portion of the current period the magnetic field will tend to attract the body 48 toward core member 44 and tend to compress spring 52. As the current changes in direction, the magnetic field will also change in direction and attract the body 48 in the opposite direction. Movement of the body 48 will be additionally aided by spring 52. At a given position of travel the striker tip 49 which is carried by body 48 will strike the periphery of the gong shell to impart the ring. The alternating current and resulting alternating magnetic field will cause the striker body 48 to vibrate back and forth inside the tube 43 and thereby continuously strike the gong shell to establish the continuous ring so long as current is applied to the coil.

The motor assembly of the present invention includes in addition to coil 39, a magnet 54 and a pair of pole pieces 55. Magnet ?4 has a rectangular shape and slips, as seen in FIG. 3, in the four grooves 32 and extends between bosses 33 and post members 30. Thus, the length of magnet 54 is approximately equal to the distance between one groove 32 on one pole piece and the opposite groove 32 on the opposite pole piece. Also, the width of magnet 54 is approximately equal to the distance between one of the pair of grooves 32 on each post 30.

Pole pieces 55 are generally rectangular in shape and have an extended longitudinal slot 56 formed extending from one end toward the central portion of the pole piece. A tab 57, which is bent from a portion of the pole piece to a positon at right angles to the body portion, is provided at the pole piece end opposite slot 56.

As mentioned above, the coil assembly 39 includes a bobbin 40 and windings 41. Bobbin 40 includes a generally cylindrical tubular portion 58 and a pair of end portions 59 which are preferably either square or rectangular in shape. The width of the bobbin end portions 59 is approximately the same as the width of the magnet 54 and approximately equal to the distance between the pair of grooves 32 on each of the posts 30. At least one of the sides of bobbin ends 59 extending between the two sides that are received in grooves 32 should be flat for purposes to be discussed more in detail below.

The assembled motor structure of the bell construction of the present invention can be seen with specific reference to FIGS. 2, 4, 5 and 9. Magnet 54 is placed in a position extending between the two posts 30 and between the two bosses 33 and adjacent to the front wall 24 of the housing. The assembled coil, including the bobbin and windings, is received in the grooves 32 with one of the edges of the ends 59 resting on or abutting one of the surfaces of the magnet. The striker assembly 37 extends through one of the hole 36 in one of the posts 30 through the cylindrical portion 58 of bobbin 40 and through the second hole 36 in the second post 30, and projects outside the housing, with striker tip 49 located adjacent to gong shell 20. Each of the pole pieces 55 are positioned in deep grooves 31 in posts 30. Tab 57 which has a hole 62 formed therethrough will be positioned at a point within slot 34 in post 30.

3,550,118

The width of slot 56 is approximately equal to the outer diameter of tubular portion 43 of striker assembly 37. Thus, pole piece 55 is located in groove 31 with striker 37 located at a position in slot 56, with the bottom of slot 56 abutting striker assembly 37. Tab 57 of pole piece 55 is located a slight distance above the bottom of slot 34 34. A threaded hole 60 is formed in the bottom of slot 34 to receive a screw 61 which passes through hole 62 in tab 57.

The procedure for assembling the motor structure bell construction of the present invention is generally as follows. A housing which has holes 36 and 60 preformed therein is provided and magnet 54 is placed in position by sliding the same to the bottom of posts 30. A coil assembly 39 is placed in grooves 32 to the proper position, and striker assembly 37 is inserted through hole 36 in one of the posts through the tubular portion 58 of the coil assembly and through the second hole 36 in the other post 30. Pole pieces 55 are then placed in position and screws 61 are placed through holes 62 and screwed into holes 60. The bottom of slot 56 will bear upon striker assembly 37, as seen in FIGS. 2 and 5, and screw 61 may be tightened to hold the striker assembly in firm position. In addition, the edges of bobbin ends 59 will bear against the magnet 54 to hold the same in place. Thus, pole pieces 55 bear on striker assembly 37 which in turn bears upon the bobbin 40 which bears upon magnet 54. It can, therefore, be seen that the motor structure assembly is held together by the two screws 61 passing through pole piece tab 57.

Pole pieces 55, in addition to acting as retaining members for the motor structure assembly, form a part of the magnetic circuit of the motor structure of the present invention. In addition to the pole pieces, the magnetic circuit includes magnet 54 and coil 39. Thus, the magnetic flux, beginning with the coil, passes through one pole piece, through the magnet to the other pole piece, and back to the coil. It can, therefore, be seen that magnet 54 aids or assists the magnetic field established by the alternating current passing through windings 41 of coil assembly 39.

Alternating current may be supplied to the solenoid coil 39 by attaching lead-in wires 42 directly to power supply lines. However, it may be desired to provide the assembly with a built-in power supply plug. Such plug is shown in FIGS. 2, 6, 7 and 9. A female socket 63, of the usual type, may be mounted in a hole in socket mounting plate 64. Wires 42 which lead to the coil may be attached, one each, to each one of the sockets in socket assembly 63. A male plug 65 mounnted on back mounting plate 66 and attached to supply lines 67 will, when the housing is mounted on the mounting plate as will be described below, provide power to the motor structure through the male prongs 68 which are inserted in the sockets of female assembly 63.

As seen most clearly in FIG. 6, female socket mounting plate 64 is attached to the top of the pair of posts 30 by a series of screws 69. Notches 70 may be formed in the ends of socket mounting plate 64 so that access can be had to screws 61 for adjustment of strike assembly 37.

For maximum ringing quality and efficiency, the striker tip 49, which strikes the periphery of gong shell 20, should contact the gong shell at approximately the point of maximum velocity. After the bell has been assembled and the gong shell mounted, the bell construction may be tested by supplying power to the coil. The striker can then be adjusted for maximum ringing efficiency by loosening slightly the two screws 61, and sliding the position of the striker, relative to the gong shell, either closer thereto or farther therefrom. The maximum amount of ring produced can be measured by any suitable or convenient method. After the most efficient position of the striker assembly has been located, screws 61 can be tightened again. Tightening of screws 61 will tend to force the pole pieces 55 toward the front wall 24 of the housing. Striker assembly 37 will be firmly retained in position, since the bottom of slot 56 will bear tightly against striker 37 retaining it in hole 36 in posts 30. Similarly, this will hold coil assembly 39 and, therefore, magnet 54 firmly in position.

A further feature of the present invention involves mounting plate 66, associated with the bracket 71 which is mounted on intermediate wall 27. Mounting bracket 71 is generally U-shaped in cross section and includes a base portion 72, first leg 73 and second leg 74. Leg 74 has an elongated slot 75 formed therein to receive on offset tab 76 which extends first inwardly and then upwardly from mounting plate 66 toward the interior of housing 21. A hole 77 is formed in the lower end of mounting plate 66 and a corresponding hole 78 is formed in the lower portion of mounting flange 28 of housing 21. A screw 79 passes through hole 78 in the housing and is threadably engaged in hole 77 in the mounting plate.

In accordance with this aspect of the present invention, the top edge of U-leg 73 bears against mounting plate 66 and mounting plate 66 pivots about this point. This pivotal arrangement is established because the distance between the inside face 76α of tab 76 and the outside face 80 of mounting plate 66 is slightly less than the distance between the top of leg 73 and the upper edge of slot 75. Thus, when the bell is mounted in the position shown in FIG. 2, tab 76 is flexed very slightly toward the inside of the bell housing and mounting plate 66 is flexed slightly inwardly at its lower end toward the interior of bell housing 21 and will be under slight tension.

This construction serves a two-fold purpose. First, it enables the mounting of the bell assembly on the mounting plate 66, which may have previously been mounted on a wall 81 by screws 82 passing through holes 83, by using the single screw 79. Secondly, it enables the bell housing 21 to be firmly and securely mounted at the desired location while only using one screw and yet while mounted in a stressed condition to absorb vibration to which the housing will naturally be subjected from striker operation.

One important feature of the electric bell construction of the present invention is that the housing 20 and posts 30 are formed as an integral unit. This construction can be accomplished by any form of casting or other means. However, it is preferable to die-cast the housing with its integral upstanding posts 30. The provision of the integral upstanding posts 30 eliminates a substantial number of parts which were previously required in prior art constructions.

Another important aspect of the present invention is that the unique construction of the posts with the integrally formed grooves 32 and bosses 33 provide a cavity in which magnet 54 may be placed by itself, without the provision of complicated clamping and retaining means. This construction also permits the magnetization of magnet 54 after assembly of the motor structure in the bell housing. While it is not necessary to magnetize magnet 54 after assembly it is preferrable to follow this procedure since it eliminates any problems that might arise during assembly particularly if a cast steel or cast iron housing is used.

Another important aspect of the present invention is that the entire bell motor assembly is held together with two screws. That is, screws 61, of which only two are necessary, hold together the entire motor structure including striker, magnet and coil. For mounting the completed bell assembly on a wall, a single screw 79 is necessary. Thus, it can be readily seen that the procedures for assembling the bell of the present invention are extermely simple and do not require complicated jigs or fixtures and can be accomplished in a relatively short period of time. This enables a great savings in both labor and parts and materials.

A further important feature of the bell construction of

3,550,118 the present invention is the provision of the lateral adjustment of the striker assembly. This adjustment is possible after completion of the bell. As indicated above, screws 61 may be loosened and striker assembly 37 can be moved laterally in hole 36 and through the interior portion of the coil to adjust its position in relation to the gong shell. This is not only important when considering that the striker needs to be adjusted for maximum ringing efficiency during intial construction, but also permits the adjustment of the striker for routine maintenance after the bell has been mounted at its ultimate location.

A still further important aspect of the present invention involves the relationship between the mounting bracket 71, mounting plate 66 and the female and male plug assemblies, the male portion of which is mounted to mounting plate 66 and the female portion of which is mounted on the bell housing posts 30. This construction permits premounting the mounting plate 66 at the desired location in a wall and provides a connection between the male plug 65 to an alternating current power supply. The bell housing may be mounted by positioning tabs 76 in slot 75 and fastening screw 79 to hole 77. The prongs 68 of male plug 65 will automatically engage the socket in female assembly 63. Thus, when assembled on the mounting plate 66, the motor structure is automatically connected to a power supply. Conversely, when the bell housing is removed from mounting plate 66, power is automatically disconnected from the motor structure and work on the motor structure can be done without power and without having to loosen wires from terminals.

A still further important feature of the bell mounting construction of the present invention is that by using the unique mounting plate assembly 66 and mounting bracket 71, it is possible to eliminate a hole which has been commonly used in prior art constructions. Such a hole or slot has been normally provided in prior art housings for mounting the housing and is an easy access for rain and other weather elements. This objectionable hole is, thus, eliminated from the housing by the provision of the unique mounting plate and bracket assembly.

It should be understood that certain of the elements comprising the present invention can be changed without departing from the scope of the invention. For example, the position of female socket assembly 63 and male socket assembly 65 could be reversed. That is, the male assembly 65 could be mounted on socket mounting plate 64, and the female socket could be mounted on mounting plate 66. Similarly, the exact shape of posts 30 can be varied without departing from the scope of the present invention as well as the exact shape of pole pieces 55 can be varied without departing from the scope of the present invention. Various changes could also be made to the striker and coil while still embodying the principles of the present invention.

The most important aspect of the present invention is the provision of a combination of elements, each of which coacts together with other elements of the bell construction to provide a bell which can be manufactured and assembled with a minimum number of parts, and without the necessity of providing a complicated set of mounting brackets and the like. Not only are manufacturing costs kept at a minimum, but assembly costs and other related cost factors will be substantially reduced because of the provision of the unique construction of the present invention.

In the foregoing description, certain terms have been used for brevity, clearness and understanding but no unnecessary limitations are to be implied therefrom, because such words are used for descriptive purposes herein and are intended to be broadly construed.

Moreover, the embodiments of the improved constructions illustrated and described herein are by way of example and the scope of the present invention is not limited to the exact details of construction shown.