US2799850A - Portable fire alarm - Google Patents

Description

July 16, 1957 H. B. THOMAS PORTABLE FIRE ALARM Filed Sept. 25, 1955 2 Sheets-Sheet l a; w u: lzvmvrox.

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ATTOZ/VEYS July 16, 1957 THOMAS 2,799,850

PORTABLE FIRE ALARM Filed Sept. 25, 1955 @Sheets-Sheet 2 4 /Z H/5 49 /7 {i h Ii 56 23 l 1 U 5 AM I *QEMFLJ 1 Ti INVENTOR.

Hf/VEY 5. 77/0/1/A 5 mum, mm' AM-44m A77'0EA/5Y5 meanse PoRrAeLE rune ALARM Henry B. Thomas, Troy, N. C., assignor to Jesse Calvin Greene, Greensboro, N. C.

Application September 23, 1955, Serial No. 536,229

2 Claims. (Cl. 340-227) This invention relates to fire alarms, and more particularly to an improved fire alarm of the portable, battery operated type.

The main object of the invention is to provide a novel and improved portable fire alarm device which is independent of the electric power line circuit of the building in which it is employed, which is simple in construction, which may be easily placed in the most appropriate location in the building or other area to be protected against fire, and which is entirely automatic in operation.

A further object of the invention is to provide an improved portable fire alarm unit which is inexpensive to manufacture, which is compact in size, which is easy to adjust for operation at a predetermined temperature, and which is provided with means for testing the device manually, if so desired.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

Figure l is a front elevational view, partly in vertical cross section, of an improved portable fire alarm device constructed in accordance with the present invention.

Figure 2 is a vertical cross sectional view taken on the line 22 of Figure 1.

Figure 3 is an enlarged top plan view of the device taken on the line 3-3 of Figure 1.

Figure 4 is a cross sectional detail view taken on the line 44 of Figure 3.

Figure 5 is an enlarged cross sectional detail view taken on the line 55 of Figure 1.

Referring to the drawings, the improved fire alarm device is designated generally at 11 and comprises a suitable support which may consist of a vertical back plate 12 to which are secured spaced horizontal cross bars 13, 14, 15 and 16, as shown in Figure 2. Secured to the cross bars 13 to 16 is a plate member 17 formed in its upper portion with an aperture 18 shaped to receive a bell 19 and an electric motor 20. As shown in Figure 2, the bell 19 is provided with an apertured top lug 21 through which extends bolts 22 securing the bell 19 to the upper portion of plate 17 at the top marginal portion of the aperture 18. Respective side blocks 23 and 24 are secured to the side marginal portions of the plate 17 on opposite sides of the bell 19, as shown in Figure l.

The motor is suitably secured in the lower portion of the aperture 18 and the motor shaft, shown at 25, extends rotatably through an arm 26 secured to a bracket member 27 rigidly fastened to the plate 17. Designated at 28 is a horizontal cross bar which is rigidly secured to plate 17 and to the bottom edges of the side blocks 23 and 24, the transverse cross bar 28 being recessed at its upper intermediate portion, as shown at 29, to receive the lower portion of the electric motor 20.

Secured to the bottom marginal portion of the plate 17 is the bottom cross bar 30 which is coextensive transversely with the plate 17. Secured to the ends of the cross bar 30 and to the side edges of plate 17 are the United States Patent ice respective side walls 31 and 32, said side walls being also secured to the ends of the cross bar 28 and to the respective outer side surfaces of the side blocks 23 and 24.

Thus, a rectangular enclosure 33 is defined between the cross bar 28 and the bottom cross bar 30. Secured in said enclosure are the vertical separator bars 34 and 35 defining three generally similar spaces shaped to receive respective batteries 36, 37 and 33, as shown in Figure 1. As shown, the batteries 36 and 38 are upright and the intermediate battery 37 is inverted. The bottom of the case of battery 38 is engaged by a terminal stud 39 threaded through the cross bar 30, said terminal stud being connected by a suitably insulated wire 40 to one terminal of the electric motor 20. A resilient spring contact member 41 is secured to the cross bar 28 and engages the center contact of battery 38 at one end thereof and the end of the casing of the battery 37 at the other end thereof. A terminal screw 42 is threaded through the intermediate portion of the bottom cross bar 36 and engages the center contact of battery 37. A spring contact member 43 is secured to the cross bar 30 and connects the terminal screw 42 to a similar terminal screw 44 threaded through the cross bar 3d and engaging the bottom of the casing of the battery 36. A resilient contact spring 45 is connected to the cross bar 23 and engages the center contact or" battery 36. A suitably insulated wire 46 connects the spring contact 45 to a contact member 47 secured to the top edge of side block 23. As shown in Figure 1, the contact member 47 extends inwardly over the bell 19. A similar contact member 48 is secured to the top edge of side block 24, extending inwardly over bell 19 from the opposite side thereof with respect to the contact member 47. A suitably insulated wire 4S connects contact member 48 to the remaining terminal of the electric motor 20.

Designated at 50 is a spirally coiled bimetal thermostat spring whose inner end is secured to a horizontally extending rod 51 which is supported in a looped bracket 52 secured to and extending upwardly from the side block 24. Secured to the end of the rod 51 laterally adjacent the supporting loop of bracket 52 is a resilient arm 53. A U-shaped bracket 54 is secured to the upper portion of plate 17 adjacent the arm 53. Secured to the arm 53 is a vertical upstanding stud member which extends slidably through the respective horizontal flanges of the U-shaped bracket 54 and is provided on its top portion with a wing nut 56. A coiled spring 57 surrounds the lower portion of the stud 55, bearing between the bottom fiange of bracket 54 and the arm 53, biasing the stud 55 downwardly. By adjusting the wing nut 56 on stud 55, the arm 53 may be rotated, whereby the rod 51 may be angularly adjusted, and whereby the spirally coiled bimetal member 5%) may be similarly angularly adjusted. Secured to the outer end of the spirally coiled bimetal member 50 is a horizontally extending contact member 58 which extends over the ends of the contacts 47 and 4S and which is normally slightly spaced therefrom, as shown in Figure 1. Upon a predetermined rise in temperature, the spirally coiled bimetal member 50 flexes sufiieiently to cause the contact member 53 to bridgingly engage the contacts 47 and 48, closing the energizing circuit of the motor 20, whereby the motor is driven by the series-connected batteries 36, 37 and 38. The amount of temperature rise required to cause the contact member 58 to engage the stationary contacts 47 and 48 can be adjusted by the adjustment of the wing nuts 56, as above described.

Designated at 59 is a first plunger member which is slidably mounted in an angle bracket 60 secured to the top portion of plate member 17 over the movable contact member 58, the plunger member 59 being biased up- 3 r wardly' to the" position thereof shown in Figure 2 by a coiled spring '61- surrounding the shank of the plunger between the enlarged head thereof and the horizontal arm of the angle bracket 60, as shown in Figure 2. A collar upward movemenfof the plunger member 5910'- the-positron thereof shown in Figure 2'; When it is desired to cause the ontact 58 to brid inglyengage the stationary contacts 47 and 48, for example, for te'stingthe'i device, the plunger is manually'pushed downwardly; the. end or" the: plunger acting against the movable contact member 58, to force said movable contact member intoconte'ct 'w'ith'the" stationary contact eiem'ents' 47 and 48.

Desi nated at 64 i a generally arched bracket plate having'the lower" ortions of its legs secured to the cross 28 a's'ish'owniin Figures I and 2 A pivot bolt 65 is' mounted in the top portion of" the bracketplate' 64,. and rotatably mounted on the pivot boltjis' a sleeve 66, secared to the sleeve 66 is'a relatively large gear 67 which meshes with a smaller gear 68 mounted on the motor shaft25. Also secured on the sleeve 66 is'a ratchet wheel 69 having trianguiar teeth 70. As shown in Fig? ure 2, the upper. portion of the ratchet whee169 projects into the lower portion of the bell 1 9;

Secured respectively to the sidewalls 31 and 32 are angle brackets 71 and 72, and pivoted to the lower portions-of the angle brackets 71 and 72, at 73' and 74 respec.- tively are the respective hammer elements 75 and 76 en ageabie with o posite side po tions of the bell 19, the res ective hammer elements having their shankl portions eite'ndinglthr'ough respective bifurcated brackets 77 and 78 secured to the respective an le brackets 71 and 72. Secured in each bracket 77 and 78 is a respective coiled spring79 hearing against its associated hammer member 75hr 76, biasing the hammer members inwardl namely, toward the bell 19. Secured to the res ective hammer members 75 and 76 are respective follower arms 80' and 8-1 which res ectivel engage trian ular teeth on the ratchet wheel 69 at opposite sides of said ratchet wheel, asshown in Figure 1, the follower arms so ands-1' being biased downwardly by respective coiled springs 82- and 83 connectin the follower arms to the ross balrZS. I

[is shown in Figure l, the follower arms 80 and 81 simultaneously engage different portions or the trian ular ratchet teeth 7a at the opposite sides of the ratchet wheel 69, whereby'when the wheel 69' rotates, the follower arms are released by the ratchet teethat different times, so that the hammer members 75 and 76- en age the bell' 19 in sequence, rather than simultaneously.

In operation, when the temperature adjacent the device rises to a value suflicient to cause the thermo-responsive member 50 to move the contact element 58 into bridging engagement with the stationary contacts 47 and 48, motor 20 is energized and rotates the ratchet wheel 69, causing the hammer elements 75 and 76 to be sequentially oscillated and to strike the bell 19 in sequence, providing a loud warning signal.

As above explained, the operating temperature of the device can be adjusted by adjusting the wing nut 56 to adjustthe normal rotated position of the shaft 51. Also,- as above explained, the device can be tested-by depressing the plunger 59 manually, to energize the motor 20 and to determine whether the device is in working condition.

While a specific embodiment of an improved portable fire alarm device has been disclosed inthe foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

l; A fire alarm device comprising a. support, a bell mounted on said support, respective hammer elements pivoted to saids'upport' on opposite: sides of said bell and being movable 'the're'against, spring means biasing said hammer elements against: said bell, a motor mounted on said support, a ratchet wheel. rotatably mounted on said 7 support between said h'ammer'elements', means drivingly coupling said wheel to said motor, respective follower arms secured to said hammer elements and engaging the opposite sides of the periphery of said ratchet wheel, said periphery comprising successive triangular ratchet.

teeth, cliifereiit follower" arms" engaging diiferent' portions of said teeth on the opposite sides of the ratchet'wheet, such thatthe follower arms are released by the ratchet teethlat difierent times when the ratchet wh el rotates,

a battery mounted on. said support, a thermo-responsive being movable thereagainst, spring means biasing said hammer elements again'stsaid' bell, a motor mounted on said support, a.- ratchet wheel rotatably'mounted onlsaid support between said hammer elements, means coupling. said wheel to said motor, respective follower arms secured .to said hammer elements and" engaging the Opposite sides of the periphery of said ratchet wheel, said periphery comprising? successive triangular ratchet teeth, said'fbllower. arms 'engagingdifierent portions of dilferent teeth at saidopposi't'e sides of the periphery of therat'chet" wheeI, such that the follower arms are released by the ratchet teeth at' different times when the ratchet wheel rotates, a batterymounted on said support, a pair" of spaced contacts rigidly mounted on said support, circuit means connecting said spaced contacts, motor andtba't-fery in series, a spirally coiled resilient bimetal strip disposedbetween said spaced contacts, means securing the inner end of said" coiled bimetal strip to said support-,Qand a conductive member secured to the outer end of said bimetal'st'rip and extending over saidspaced contacts, said bimetal strip being flexible in response to temperature rise to move said conductive member into simultaneous engagement with said spaced contacts. a

I 7 R eferences Citedin the filerof this patent t, UNITED STATES PATENTS- 7'57, 2 7r ce1 Apr; 12, 1904 1,260,461, Schuyler Mar; 26, 1918' 25505673 Cufalo May 1', 195 1; zsitoie Nnceio Sept; 16,-.1952' 2,710,39? Goldberg m J'nne 7, 1 's 7 FOREIGN PATENTS 657,509 Germany Feb. 17, was

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