US2553244A

US2553244A - Alarm signal box

Info

Publication number: US2553244A
Application number: US82881A
Authority: US
Inventors: Jack I Ellmann
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-03-22
Filing date: 1949-03-22
Publication date: 1951-05-15
Anticipated expiration: 1968-05-15

Description

2 Sheets-Sheet 1 Filed March 22, 1949 Ema- I...

m H m M m I. m m 4 4 4 2 M y 1951 J. I. ELLMANN 2,553,244

ALARM SIGNAL BOX Filed March 22, 1949 2 Sheets-Sheet 2 INVENTOR. Jr/r J. ta'amxwwv Patented May 15, 1951 UNITED STATES FATENT OFFICE ALARM SIGNAL BOX Jack I. Ellmann, Washington, D. 0.

Application March 22, 1949, Serial No. 82,881

3 Claims. i

This invention relates to alarm signal boxes and has more particular reference to signal boxes of the so-called break-glass type, such as are employed, for example, in fire or other alarm systems.

One object of the present invention is to provide a novel and improved alarm signal box of the above type having a hinged hammer adapted to smash the glass into fragments concentrically around the switch for positive release thereof and simultaneously prevent glass fragments from flying out of the box.

Another object of the invention is to provide an alarm signal box, as above characterized, having means for carrying a spare glass to replace a smashed glass.

Another object of the invention is to provide an alarm signal box, as above characterized, having means to permit testing of the alarm system without breaking the glass or completely opening the box.

Another object of the invention is to provide an alarm signal box, as above characterized, having means for preventing the glass from falling out when the box is opened for glass replacement.

Another object of the invention is to provide an alarm signal box, as above characterized, in which the glass is resiliently held in its frame so that it will have sufficient give to prevent shattering by the hammer when the only force exerted by the hammer is due to its own weight.

A further object of the invention is to provide a simple, inexpensive, rugged signal box which is efiicient and safe in operation, and one which is quickly and easily assembled and installed.

Other objects and advantages of the invention will appear in the following specification when considered in conjunction with the accompanying drawings, wherein:

Fig. 1 is a perspective view of a preferred form of an alarm signal box constructed in accordance with the present invention;

Fig. 2 is a vertical sectional view taken on the line 22 of Fig. 1;

Fig. 3 is a plan view, with parts broken away, of the mounting plate of the box shown in Fig. 1;

Fig. 4 is a plan view with parts broken away, of the under side of the cover plate and hammer of the box shown in Fig. 1;

Fig. 5 is a fragmentary view showing the relative positions of the break-glass, break points, and switch, when the alarm box cover is closed and the alarm is ready to be operated;

Fig. 6 is a view similar to Fig. 5, but showing is hinged to the bottom of the mounting plate;

and

Fig. 8 is a fragmentary perspective view of a.

modified form of mounting plate having a spare glass holder frame formed integral therewith.

Referring now to the drawings, there is shown in Figs. 1 to 6, inclusive, one modification of an alarm signal box constructed in accordance with the present invention and comprising a mounting plate l6; 2. cover plate H, a hammer i2; and a switch mechanism [3.

The mounting plate It; is shown as a generally fiat, rectangular plate of cast metal having a spaced pair of upstanding apertured lugs l3, it formed integral therewith on its upper end. The plate is shown as being provided with a pair v.of oblong openings i5, it which receive the screws by means of which the plate is attached to a wall or a switch box, and a circular opening ii in which the switch mechanism [3 is mounted.

A pair of upstanding lugs ii are formed integral with the plate Hi and positioned in substantially horizontal alignment with the circular opening IT. The upper portions of the lugs have rectangular recesses i9 formed therein which form supports for a spare glass 2%. An upstanding lug 2| positioned above the lugs 18- and adjacent the left hand edge of the plate It, as viewed in Fig. 3, forms a stop for the spare glass.

The cover plate H is shown as a hollow-like cast metal member having a fiat front wall 22 merging into rounded top and bottom walls 23, at and having

vertical side walls

25, 25. The plate I l is provided with a spaced pair of integral apertured lugs 21, '28 projecting forwardly and upwardly from its upper edge (see Fig. 1). The front wall 22 of the plate Ii has a rectangular opening 29 formed therein, the edges of which form a frame for a rectangular frangible plate 39 mounted on the inside of the cover plate. The plate 30 may be made of any suitable frangible material; preferably, and as shown, the plate is made of glass. The glass plate '36 is supported on the inside of the cover plate it by means of a spaced pair of integrally formed inwardly and upwardly extending tongues El, 32. The space between the upwardly extending portions of the tongues and the rear surface of the front wall of the plate forms recesses 33, 3:2 in which the bottom edge portion of the glass plate 33 is received.

The hammer I2 is shown as a flat, generally rectangular plate of cast metal having a spaced pair of rearwardly projecting apertured

lugs

35, 36 formed integral therewith along its upper end. The hammer is made of a width greater than the width of the rectangular opening 29 in the cover membe H to prevent glass splinters from flying out of the opening when the hammer is used to shatter the glass plate 36.

An integral inwardly projecting cylindrical lug 31 formed on the rear surface of the hammer provides a striking head. The outer end of the lug 31 has a rounded concavity 38 formed therein with the circular edge of the concavity serrated as indicated at 39.

The switch mechanism l3 in the particular embodiment shown is substantially identical in construction to that shown in U. S. Patent No. 1,883,786, issued October 13, 1932, to H. C. Housen et al., for a Push Switch, and comprises a laminated insulating base 4% containing suitable contacts to which the electrical circuit wires 4!, 32 are attached; a metal casing 33 embracing the insulating base and having an opening in its top; an externally threaded sleeve 45. secured in the opening in the casing; a hollow cylindrical plunger :55 slidably mounted within the sleeve;

and a button 46 slidably mounted in the plunger The switch is mounted on the rear of the mounting plate with the threaded sleeve l4 projecting through the circular opening I! and held in place by means of lock nuts *1? and 48. Proferably, and shown, t1 e threaded sleeve 44 is provided with a longitudinal keyway slot =13 in which is received a keyway lug 5i? projecting from the mounting plate into the circular opening ii to prevent the switch from turning.

As shownin Figs. 1 and 2, the mounting plate Hi, the cover plate ll, and the hammer [2 are hingedly connected together by a rod 5% extending through the horizontally aligned apertured lugs formed on the tops of these members.

The lugs on the cover plate are tioned to the outer walls of the lugs on the mounting plate and the spaced lugs on the hammer are positioned to engage the inner walls of the on the mounting plate, thereby preventing any lateral inoven :nt of these members relative to each other on the rod l.

Prefers ly, and as shown s. l and 2, the height and width of the cover plate is he same as that of the mounting plate, so that when the cover plate is resting on mounting plate, their respective top, bottom and side walls will be flush with each other. The cover plate is held secured in its closed position on the mounting plate as shown in Figs. 1 and 2, by means of a Philips head screw 52 extending through a countersunk opening in the cover plate and threaded into a screw hole extending through the mounting plate.

The depth oi the side walls of the cover plate is such that when the cover plate is in closed position with the glass plate 39 held pressed against the window frame, there will be a slight space between the glass and the tops oi the lugs The switch mechanism i3 is adjustably secured on the mounting plate so that the plunger 65, when in its depressed position, as shown in Fig. 2, will be slightly below the tips of the lugs 3 with the button 48 in a se:r.-i--depressed position and engaging the glass as to hold it against its frame. This construction permits a slight "give to the glass plate. When first struck by the hammer, the glass plate will press the button 46 inwardly until the glass plate rests against the tips of the lugs it, where continued inward movement of the hammer shatters the plate (see Figs. 5 and 6). This resilient mounting of the glass plate provides suficient give to permit the hammer to fall from its highest raised position against the glass without breaking it. This is true even when the glass plate is made of ordinary window glass. In this connection, it should be pointed out that the

recesses

33, 34 in which the lower edge portion of the glass plate rests is made of sufficient width to take care of the inward movement of the glass. If desired, and as shown in Fig. 2 the inner surface of the upwardly extending portion of the glass holding tongues 3 i 32 may be positioned to lie in the same vertical plane witlrthe tips of the lugs 18 so that the tongues 3|, 32 will act as break points along with the lugs 8.

The striker head or lug 3'? of the hammer is so positioned thereon that when the hammer is moved to break the glass plate the cylindrical striker head will be concentric with the plunger l5 and, due to the concavity in the head and the resiliency of the push button 46, the breaking impact of the hammer on the glass will not damage the switch and, after the glass has been shattered, the striker head will not hit the switch as the push button 45 will be received in the concavity in the head. (see Fig. 1). Also, due to the serrated circular edge the head striking the lass directly 1' the itch in a concentric circle, the glass all around the switch breaks into fragments which drop out of the way of the switch tip and permit it to function freely. The serrated edge provides a plurality of breaking tips, thereby concentrating the force of impact at a plurality of points of small area, making the hammer "lOljE-l effective and causing glass to ULJe break into small fragments rather than splintering. Experience has shown that splinters Sometimes engage the switch tip and hold it down, preventing it from sounding the alarm.

When the mounting plate it, cover plate H and hammer 52 are assembled together and the Philips head screw tightened to hold the cover plate against the mounting plate, the glass plate 30 exerts sufficient pressure against the tip of the switch to cause its electrical contact to reverse and hold this position until disturbed, either by the breaking of the glass 01' by unscrewing the Philips screw. The switch operates in the same manner as that shown in the aforesaid patent to Housen et al. and is mounted in one line of the electric circuit of the alarm system so that when the switch tip is held pressed inwardly by the glass plate 3f the circuit is opened, and when the glass plate is broken to permit the switch to be resiliently pressed outwardly, the circuit is closed. In this connection, it should be pointed out that the Philips head screw which holds the cover plate against the mounting plate, affords a ready means for testing the alarm system without breaking the glass or opening the signal box. The testing is accomplished by loosening the Philips head screw a suflicient number of turns to permit the cover plate to release the pressure on the switch tip and permit it to be resiliently pressed outward a distance sufficient to close the circuit and sound the alarm.

In Figure '7, there is shown another modification of an alarm signal box constructed in accordance with the present invention. This modification difiers from that shown in Figs. 1 to 6,

inclusive, in that the mounting plate I9 is provided with a spaced pair of apertured lugs l3, l4 along its upper edge and a spaced pair of integral apertured lugs 53, 54 at its bottom edge; the cover plate i l is provided with a spaced pair of apertured lugs El, 23 at its bottom edge and is hingedly attached. to the mounting plate by a pin passing through the apertured lugs at the bottom of the two plates. The hammer i2 is provided with a spaced pair of apertured lugs 556' along its upper edge and is hingedly mounted on the cover plate by a pin 59 passing through the apertured lugs at the tops of the two plates. Other than the foregoing, the construction of the three plates and the manner in which the signal box operates are similar to the construction and operation of the corresponding parts shown in Figs. 1 to 6, inclusive.

In Fig. 8, there is shown a third modification of an alarm box signal constructed in accordance with the present invention. In this modification, the mounting plate lil; cover plate ii"; and hammer i2 are generally similar in construction and are mounted in the same manner as the corresponding parts in the modification shown in Figs. 1 to 6, inclusive, except that the mounting plate ill is provided with an integrally formed spare glass container til at its upper end.

The spare glass container 5'1 is shown in the form of an open top rectangular box-like memher having a cover plate 58 secured thereto, as by means of a bolt 59 and a screw 69. To remove the cover plate 58, the screw Ed is unscrewed from the container and the cover plate swung to the right about the bolt 59 as a pivot, as shown in Fig. 8. A peep hole 6! is provided in the cover plate.

In the modification shown in Fig. 8, the provision of the spare glass holding means on the inat side of the box, as shown in Figs. 1 to 6, inclusive, is optional.

From the foregoing, it readily will be seen that there has been provided a novel and improved alarm signal box of the break-glass type which is simple and rugged in construction, involving only three cast metal movable parts hingedly connected together and forming a housing for the switch tip; one which is efiicient and safe in operation, mounted to insure against accidental breakage, and the hammer being adapted to smash the glass into fragments concentrically around the switch for positive release thereof and simultaneously prevent glass fragments from flying out of the box; one which permits testing of the alarm system without breaking the glass or completely opening the box; and one which provides a housing for a replacement glass plate.

Obviously, the invention is not restricted to the particular embodiments thereof herein shown and described.

What is claimed is:

1. An alarm station comprising a mounting plate having a spaced pair of upstanding projections formed thereon to provide breaker points; switch mechanism carried by said mounting plate, said switch mechanism having 'a tip portion spring biased to an extended position to close the the glass plate being resiliently;

Elf:

switch and movable to a retracted position to open the switch, said switch tip portion being positioned between said upstanding projections; hollow cover plate hingedly connected at one end to said mounting plate to form a switch box and having an opening therein covered by a replaceable plate of frangible material, said opening being positioned so that, when said cover plate is closed, said frangible plate will engage said switch tip and hold it in its retracted position; and a hammer member hingedly connected to the switch box in front of said cover plate and having striking head positioned to engage said frangible plate and shatter it against said breaker points when the hammer is struck a blow, said striking head being provided with a rounded recess in its outer end normally aligned concentrically with said tip portion of said switch mechanism.

2. An alarm signal box, as set forth in claim 1, wherein the peripheral wall of the rounded recess in the striking head of said hammer is serrated to shatter the glass around the switch tip without striking the tip after the glass is broken.

3. An alarm station comprising a mounting plate having a spaced pair of upstanding projection formed thereon to provide breaker points, said projections being provided with top opening recesses; switch mechanism carried by said mounting plate, said switch mechanism having a tip portion spring biased to an extended position to close the switch and movable to a retracted position to open the switch, said switch tip portion being positioned between and in horizontal alignment with said upstanding projections; a hollow cover plate hingedly connected at one end to said mounting plate to form a switch box and having an opening therein covered by a replaceable plate of frangible material, said opening being positioned so that, when said cover plate is closed, said frangible plate will engage said switch tip and hold it in its retracted position; a hammer member hingedly connected to the switch box in front of said cover plate and having a striking head positioned to engage said frangible plate and shatter it against said breaker points when the hammer is struck a blow; and a. spare frangible plate mounted on said mounting plate with its bottom edge engaged in the recesses formed in said upstanding projections.

JACK I. ELLMANN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,345,457 Olson July 6, 1920 1,479,608 Jackson Jan. 1, 1924 2,014,861 Neely Sept. 1'7, 1935 2,083,324 Edwards June 8, 1937 2,448,330 Sperzel Aug. 31, 1948 OTHER REFERENCES Data Sheet No. 32160, Fire Alarm Station Type NC Faraday by Stanley and Patterson, Boston, Mass, dated Mar. 26, 1946.