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Publication numberUS1920742 A
Publication typeGrant
Publication dateAug 1, 1933
Filing dateFeb 28, 1927
Priority dateFeb 28, 1927
Publication numberUS 1920742 A, US 1920742A, US-A-1920742, US1920742 A, US1920742A
InventorsChapman Arthur B, Vadnais Alexander H
Original AssigneeDouble A Alarm Company Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Protective system
US 1920742 A
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Description  (OCR text may contain errors)

Aug- 1, 1933 A. B. CHAPMAN Er AL 1,920,742

PROTECTIVE SYSTEM Filed Feb. 28. 1927 2 Sheets-Sheet 4il.

Aug. 1, 1933- A. B. CHAPMAN r-:r AL

PROTECTIVE SYSTEM 2 Sheets-,Sheet 2 Filed Feb. 28. 1927 rammed ugr, 1933 UNITED lsra'rss PROTECTIVE SYSTEM Arthur B. Chapman and Alexander H. Vadnais, Oshkosh, Wis., assignors to 'Double A Alarm Company, Inc., Oshkosh Wis., a Corporation of Wisconsin Application February 28, 1927. Serial No. 171,577

2 Claims.

This invention relates to protective systems, and it has special reference to burglar alarm and similar systems wherein a signaling device is released or an alarm sounded upon unauthorized 5 or improper entrance into or tampering with a housing or chamber that is to be guarded and protected.

Among the objects of the invention is a simplified system of the foregoing character, characterized by a number of novel features, such as the utilization of a common energy supply source associated with the signaling device both for operating the open circuit'and the closed circuit alarms of the system; circuit connections whereby some of the conductors of the open circuit alarm constitute parts' of the closed circuit alarm, and vice versa; the employment of braided, vmultiple conductor cables for establishing the alarm circuit connections where the signaling or alarm device is disposed at a distance from the guarded\device, the open circuit alarm conductors being\k preferably lformed of a plurality of parallel connected strands in such cable; special alarm elements comprising a 'plurality of adjacently disposed, resilient conducting elements, preferably constituting mechanicalvibration elements ofdiierent natural frequencies and forming part of the protected enclosure; and other characteristics which will appear from the following specification and the drawings describ- 1 ing specific exemplications of the invention.

In the drawings,

Fig. 1 is a diagrammatic vieW of the protective system `embodying one form of the invention;

Fig. 2 is an elevational View of a portion of the cable carrying the circuit conductors extending between the guarded housing'and the remotely disposed signaling device of Fig. 1, a

part of the interior of the cable being exposed 40 to indicate the structure thereof;

Fig. 3 is an elevational View of the improved spring alarm element of the invention;

Fig. 4 is an elevational view of the vibratory spring. alarm `element of another form of thev ing Iand the circuit connections between said trating protective systems embodying the invention in other forms.

The alarm system shown in Fig. 1 is of the type which is preferably employed for the protection of safes, bank vaults, or the like. In said systems the safe, or in general, the guarded structure, is disposed at some point in the interior of the building and an alarm device or signaling device that is disposed outside of thebuilding is so connected by suitable alarm circuits withv said guarded device as to sound an alarm and attract the attention of those in the neighborhood in case the guarded structure is tampered with. The signaling device is usually'disposed at a point where an alarm released thereby will be noticed by observers, or the public passing at said point. Thus, in many cases, the signaling device for protecting a safe in the interior of a vault is placed at the front wall near the entrance of the building so as to attract the attention of the passers-by when sounding the alarm.

To make a protective system of the foregoing character elfective, it is important that both the signaling device as well as the circuit connections between said signaling device and the guarded structure shall be tamper-proof. That is, they must be so arranged as to positively prevent, or at least render very diicult and improbable, the cutting out, or otherwise rendering for a time inoperative, the alarm circuit. The fact that the signaling device is disposed outside of the guarded structure and that. the circuit connections are also exposed, renders the foregoing requirements difficult to accomplish by simple means. 90

In ourcopending application Serial No. 121,45 of July 2, 1924 is described a protective system of the foregoing character in which the signaling device was enclosed in a suitable housing or cassignaling casing in the guarded structure are effected through a cable so arranged as to cause the alarm to be released in case the cable was cut or the casing walls were intended to be broken.

To this end, there was provided, what might be designated, a closed alarm circuit and an open alarm -crcuit extending between the guarded structure and the signaling casing. The signaling device within the signaling casing was included in a local energizing circuit supplied from a local 'electric energy source, this circuit being held normally open by means of a switch held in open position by an electromagnet that was energized through a pair of conductors from a second energy source disposed inside the guarded structermed, open circuit conductors, were provided between said guarded housing and said signaling casing so arranged as to cause the alarm to be` sounded if said wires were bridged over or shortcircuited. Since the open circuit wires were lead in one cable with the closed circuit wires, a person attempting to render the closed circuit protection ineffective by bridging said two wires with an auxiliary battery was likely to bridgeI over the open circuit w-ires of the cablethus causing the alarm to be sounded. The degree of protection of such system depends on the difllculty'with which the closed circuit wires can be separated and distinguished from the open circuit'wires.

One of the distinguishing features of the present invention is a circuit arrangement whereby some of the closed circuit conductors serve as part of the open circuit alarm, while part of the open circuit conductors serve as part of the closed circuit alarm, thus mutually increasing the effective protection rendered by the two alarm circuits. Another feature resides in theutilization of `a single electric energy source within the signaling casing for supplyingA energy to operate both the closed, as well as the open alarm circuits.

In the exemplication of the invention illustrated in Fig. 1, a guarded structure or housing 1 is arranged to be protected by means lof a sig'- naling device, such as a gong 2, disposed at a distance from the guarded'housing and enclosed in a signaling casing 3. In the following specicatiqn and claims the term housing will, in general, be applied to designate the guarded structure -1, while the term casing will be applied to designate the housing or box enclosing the signaling device 2, in order to simplify the nomenclature. This difference of expression in designating the two structures is not intended to in any way limit or particularly distinguish the character of the two' enclosures in respect to their construction, characteristics or otherwise. In some of the claims the term housing is intended to be applied both to the guarded structure and tov the casing surrounding the signaling device.

Both the protected housing and the signaling casing are shown as having double walls, indicated by dotted lines. The walls are preferably of conducting material and are insulated from each other to constitute part of the alarm circuit as described hereinafter.

The signaling device 2 is supplied from an electric energyysource, such as a battery 5, disposed within said signaling casing 3, through a local energizing circuit within the casing, saidcircuit including an electromagnetic switch '1. The switch '7' is normally held in open position by energizing the magnet thereof through a `suitable switch control circuit including apair of conductors O and Or, commonly designated as the closed circuit conductors, leading from said casing into said guarded housing 1.

A second pair of conductors A and B, com- V monly designated as the open circuit conductors,

are connected in parallel to the switch 'l and constitute a second external energizing` circuit for said alarm or signaling device 2, said open circuit conductors leading from said casing into said housing like the closed circuit conductors. An electromagnetic tripping switch 10 within said guarded housing is arranged to bridge said open circuit conductors A and B when tripped, to permanently short-circuit said conductors, and thereby continuously sound the alarm until the switch is reset. The tripping ymagnet for the housing switch 10 is connected between the open circuit conductor B leading from the terminal of the signaling device 2 and an additional return conductor R extending between said casing and said housing, said conductor being connected to the terminal of the source 5, having a polarity opposite that to which the open circuit conductor A is connected. 4 In order to energize the control circuit of the casing switch 7, its closed circuit conductors Oa and Or are connected within the housing 1, to open circuit conductor A and the return conductor R, leading to terminals of said energy source 5 Within the casing, the circuit connections .of said closed circuit wires Oa and Or including suitable protective alarm elements within the guarded housing such as the combination lock 15 and the labyrinth lining 16. The alarm elements are well known in the art and no extensive description thereof will be given. The lock is usually so arranged that in locked positiona circuit connection therethrough is completed and on tampering with said lock said connection is broken. 'Ihe labyrinth lining usually consists of a metallic foil ribbon pasted over an insulating layer on the interior walls of the guarded housing, said ribbon constitutingA a part of the control circuit supplying current to the magnet of the casing switch 7. The labyrinth lining is so arranged as to break open upon tampering with the walls of the guarded structure, thereby interrupting the circuit through the closed circuit conductors Oa, Or and starting the alarm.

The several wires A, B, R, Oa, Or, leading between the signaling casing and guarded housing,

are combined into a single multi-strand cable 17, such as shown in Fig. 2. According to the invention, the number of strands within the cable is greater than the number of signaling wiresl required to operate the alarms. Preferably, the open circuit conductors A and B are each formed of a plurality of similar strands which are electically connected together at the casing and housing ends of the cable, thus constituting multiple swire conductors.

son of the fact that the open circuit conductor A I constitutes a part of the closed alarm circuit including the conductors Oa and Or, and on the other hand, the closed circuit conductor Oa serves in effect the same functions as a multiple conductor for the open circuit conductor A. Accordingly, the protection of the open circuit conductors is directly increased by the closed circuit conductors of the system, amd vice versa.

111 Order to fully derive the benegts of this protective system and to render still further diicult the segregation of the closed circuit wires from the open circuit wires without releasing the alarm, the several strands of the cable are braidedand interwoven to constitute a closely tied mass of wires, making it substantially impossible to separate one wire from another without short-circuiting the wires or cutting the same.

In operation of the foregoing system the protection of the interior of the guarded structure 1l depends, in the first instance, on the closed circuit alarm elements 15fand 16 and on the maintenance of said alarm circuit, including the closed circuit conductors Oa'and Or, in operative condition. This, in turn, is secured by the provision of the braided interconnected cable 18, including the open/circuit alarm conductors A, B and the return conductor R. Thus, if the cable isdirectly cut, the de-energizatlon of the control magnet of the switch '7 will close the local alarm circuit within. the signal casing 3, continuously sounding the alarm. X

An attempt to bridge out the conductors Oa, Or without cutting the cable will, by reason of the above described multiple open circuit conductors A, B and the braided cable construction, invariably cause short-circuiting of the open circuit wires A, B. The latter are so arranged that bridging thereof for even a very short instant will energize the tripping magnet of the housing switch 10, thereby permanently establishing a short circuit across said wires and thus continu,v

ously energizing the alarm device and sounding' the same until said housing switch 10 is reset. It will be noted that the casing switch 7 is connected directly in parallel to the open circuit wires A, B so Athat closure of said casing switch for even a short instant by reason of momentary interruption of the closed alarm circuits Oa, Or, immediately trips the housing switch 10, thereby continuously sounding the alarm, even if theburglar was able to immediately restore the closed alarm circuit. f Y

The complete protective system of the foregoing character, as applied to safes or vaults that are intended to be held open from 9 A. M. to 5 P. M., for instance, is provided in addition with an alarm cut-out clock 21 disposed within the safe, and arranged to actuate a suitable shortcircuiting switch 22, to shunt the alarm elements 15 and 16 of the closed alarm circuit, including the conductors Oa and Or. When the switch 22 is in lowered position, the alarm elements15 and 16 are short-circuited making it possible to unlock the combination lock 15 and open the safe without sounding the alarm'. When the switch 2,2 is in raised condition, the alarm elements 15 and 16 are. eiective and tampering` therewith will release thealarm, as described above.

The vclosing and opening of the switch 22 is regulated by means of the clock 21 which is so arranged that when suitably set before closing thesafe, it will open the short circuit established by the switch a short interval after the safe has been closed. The alarm elements 15 and 16 are thereby included in the circuit and the protective system rendered operative. The clock thereupon holds said switch 22 in raised condition for such time as was set on the clock, say till 9 A. M., at which time the switch22 will be lowered and the short circuit again established. This will again cut out the alarm elements 15 and 16, making it possible to open the safe without sounding the alarm. A simple and effective clock performing the foregoing functions is described and claimed in the cor-pending application of Arthur B. Chapman, Serial No. 105,786, led April 30, 1926.

In order to give an external indication of the condition of the clock switch 22 so as to avoid premature opening of the clock of the safe and unnecessary sounding of the alarm, a suitable annunciator 23 .is connected between the current supply wires A and R by means of an auxiliary contact atthe switch 22, so that the annunciator is tripped upon closure of said clock switch 22.

In order to maintain the continuous current iiow through the closed alarm circuit at a given small -value, vthis circuit is made to include suflicient resistance to limit said current to a desired value. In the preferred construction, a resistor 25 is included in the circuit conductors leading to the energizing magnet of the casing' switch 7, said resistor being disposed within the interior of the guarded housing 1, for reasons pointed out hereinafter.

As a safeguard against rendering the alarm system inoperative by sho'rt-circuitingy the open circuit conductor A and the `return conductor R, leading from the energy source 5, and thereby cutting orfr the energy supply to the signaling device 2, as for instance, by cutting the cable and immersing it in a conducting liquid like mercury, an overcurrent cut-out device, such as a fuse 26, is included in the circuit/ conductors leading from said source, to open said conductors and permanently release the alarm. This is an important feature of protection characterizing the alarm system of the present invention.

Another protective feature characterizing the invention resides in the utilization of the double walls of the guarded housing and the signal casing as elements of the open circuit alarm protection. To this end, the insulated double walls of the housing and casing are electrically connected to the open circuit conductor pair A and B, respectively. Accordingly, if a burglar, or other person breaking through the walls of either casinglwith a chisel, or the like, and establishes a conducting connection between the insulated double walls, the housing switch 10 is immediately tripped, permanetly closing the alarm circuit and continuously sounding the alarm until the housing switch l0 is reset.

The protective system of the present inventiony is further characterized by a special vibratory alarm element 31 so associated with the system as to release the alarm when the housing, or, as the case may be, the signaling casing is tampered with or violently forced.

The vibratory alarm element 3l, as indicated diagrammatically in Fig. l, comprises a plurality of resilient spring members 32, 33, insulated with respect to each other and suitably held under tension to constitute mechanical vibrators adapted to be set into Vibration at their natural frequencies upon application of violence to the walls of the protected structures. As shown in Fig. 3, the vibratory spring members are suitably strung between supporting bars 41, 42, preferi ably arranged as frame units 43, constituting a portion of the enclosure of the protected housings. When such alarm elements vare used in mercantile protective systems, such as stores, or the like, such vibratory elements may be formed by Stringing the springs across skylights, back windows, and transoms, forming screen-like enclosures over said openings.

Adjacent, insulatingly mounted spring members are connected to the open circuit conductors A, B, respectively, as shown in Fig. 1, so that when contact is established between any pair of adjacent spring members the housing switch 10 will be tripped and the alarm set into action. In order to make this protection effective against direct interference with the screen-like enclosures formed by such alarm elements, it is not essential that the same shall constitute mechanical vibrators having a tendency to start vibration and contact with each other upon receiving of an external impulse. It is suiiicient for this function to make the screens by simply spanning across such windows, transoms, or the like, conducting Wires disposed sufficiently close to each other to become short-circuited upon attempt to pass through such screen. f

However, the use of spring members is advantageous even from the viewpoint of protection against direct interference with the screen-like enclosures inasmuch as the spring construction greatly facilitates the building of such enclosures. 'This is particularly the case if such screens are made in accordance with the present invention by utilizing double sets of coil lsprings, as shown in Fig. 3, an inner coil spring constituting one vibratory element 32 and an outer coil spring constituting the other vibratory element 33, surrounding said first vibratory element. Thedouble coil spring structure makes it possible to quickly make up such screens, as itis merely necessary -to pull the coil pair to 'the required length and to insulatingly secure it to the bars 41 and 42 on the opposite sides of the frame.

In the preferred construction the inner spring of one'coil pair is connected to the outer of the 'next adjacent coil pair, etc.

When used in vaults, the screen-like frame units may be arranged to constitute a distinct part of the enclosing wall structure, as indicated in Fig. 1 where the vibratory alarm element is shown between the double walls of the housing and the casing, respectively.

In order to cause the vibratory spring elements to vibrate at frequencies at which the action will be most effective, they may be provided with special weight elements 51 suitably clamped or otherwise held on the individual spring members; By increasing or decreasing the mass of said weight elements the natural period of the individual vibrators may be adjusted to lie near the range of the frequencies of external shocks applied to the safe or vault when hammering against the Walls thereof. In the preferred construction, where a large number of such mechanical vibrators is available, the natural frequencies of the individual vibrators are adjusted to lie over a Wide range so as to obtain a greater assurance that at least one of the vibrator elements will readily respond to an external shock of some particular frequency within said range.

The vibratory alarm elements may also be 1 .ide in the form of groups of three, spi-ing units, as shown in Figs. 4 to 6, wherein three coil spring members 55, l56, 57 are wound around each other and suitably spanned on a framework 58, shown in Fig. 6. The modification shown in Fig. 7 utilizes adjacently disposed, corrugated wire springs 59 in place of the coil springs. r

In the modification of the invention shown in Fig. 8, additional protection is obtained by including the vibratory spring elements as a part of the closed alarm circuit as well as the open alarm circuit. To this end, vibratory elements ofthe type shown in Figs. 4 to 6, preferably comprising three insulatingly supported spring members coiled around each other, have two coil spring members connected in series with the closed circuit conductors Oa and Or of the closed alarm circuit, the third spring member being connected to the conductor B of the open alarm circuit.

With the foregoing connections, a contact or short established between the two spring members included in the closed'circuit, will Shortcircuit the energizing coil of the operating magnet in the casing switch '7, thereby momentarily releasing said switch and tripping the housing switch 10, thus putting the alarm into action. If suflicient resistance is included inthe energizing leads supplying said closed circuit conductors Oa and Or, as by means of a resistor 25, included in series with one of said conductors, shortcircuiting of the spring members serially connected with said closed circuit conductors will not constitute a complete short on the battery, and accordingly, will merely release the alarm, as explained above. However, if the short circuit current iiowing into such short should be excessive, the cut-out device 26 will open, which would also release the alarm.

By connecting the third coil spring member 58 to the open circuit wire B, the vibratory alarm element of the system shown in Fig. 8 provides also for the' actuation of the open alarm circuit in case of contact between adjacent spring members, since the immediately adjacent coil spring member 56 is a part of the closed circuit conductors Oa, which, in turn, has a direct connection with the other open circuit conductor A of the alarm system. All-around eflicient protection is thus provided with a minimum of complications.

In the alarm system shown in Fig. 9, one of the closed circuit conductors Oa of a system such as shown in Figs. 1 and 8, is omitted and the open circuit conductor A is directly utilized to perform the functions of the omitted open circuit conductor. The energizing magnet of the casing switch 'I is, accordingly, directly connected to said open circuit conductor A within said casing.

`Two sets of vibratory alarm elements, one co- "operating with the closed alarm circuit and the other cooperating with the open alarm circuit, are provided. To this end, one set of adjacent coil spring members 65, 66 of a vibrator structure, as described above, are directly connected in series with the closed circuit conductor Or and the conductor A which servesboth as a closed and open circuit conductor. Another set of adjacent spring ,members 67, 68 are connected in parallel to the open circuit conductors A and B, functioning like in the arrangement of Fig. 1.

In the modification shown in Figs. 8 and 9, the operating current is arranged to be normally supplied from the house current supply line 61, the battery 5 serving only as a standby source of energy. An electromagnetic actuating switch 62 holds the line normally connected to the supply circuit, but on failure of the supply line, the switch automatically connects the standby battery to operate the alarm circuit.

The invention is susceptible of many other modifications that -will suggest themselves to those skilled in the art, such as the utilization of other switching and tripping means than those shown and described; substitution of other overcurrent cut-out devices in place of the fuses; the employment of multiple conductors for the other portions of the alarm circuit, etc. It is desired, however, that the appended claims be construed to covercall such modifications.

What we claim is: l. In a protective system, a guarded housing,

ha signaling casing outside of said-housing, a

, current and the portion of one of said pairs of conductors which extends from said energy source to said guarded housing, an additional conductor extending between said housing and said casing and said signaling device; and a coil at said guarded housing connected between said additional conductor and the portion' of the other of said pair of conductors'extending from said energy source to said guarded structure, and a trip circuit closer controlled by said last named coilto permanently connect said additional consov ductor and said first mentioned portion upon the energization of said coil.

2. In a protective system, a guarded housing, a signaling casing outside of said housing, a signaling device and an energy source within said casing, a local. energizing circuit for said signaling device within said casing, a switch included. in said circuit, a coil for the switch, a protective circuit including said energy supply source, a pairof conductors extending from said source to said guarded housing and said coil at said signaling casing; said coil vclosing said switch to energize said signaling circuit on rupture of said protective circuit; and normally open protective circuit including said source of current,

and one of said pair of conductors, an additional conductor extending between said housing and said casing and said signaling device; and a coil at said guarded housing connected between said additional conductor and the other of said pair of conductors, and a trip circuit closer controlled by said last named coil to permanently connect said additional conductor and said one of the conductors upon the energization of said coil.


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2492432 *Jul 27, 1946Dec 27, 1949Electro Protective CorpElectrical protective alarm system
US2531958 *Dec 18, 1942Nov 28, 1950Stewart Warner CorpProtective device for fuel lines or the like
US2627065 *Dec 28, 1949Jan 27, 1953Certified Burglar Alarm SystemBurglar alarm box
US2686909 *Dec 28, 1949Aug 17, 1954Certified Burglar Alarm SystemElectric burglar alarm system
US2701874 *Jan 23, 1950Feb 8, 1955Harold A MearsBurglar alarm system
US2943308 *Mar 15, 1956Jun 28, 1960Westphal Everett AProtective alarm system
US2955282 *Sep 19, 1957Oct 4, 1960Boyle Joseph JAlarm system
US3160871 *Apr 2, 1962Dec 8, 1964Gen Cable CorpTap-proof security communications cable
US3192517 *May 11, 1962Jun 29, 1965Bay State Security CorpBurglar alarm
US3603959 *Jan 6, 1969Sep 7, 1971Us Air ForceWarning interlock system for unlocked safes
US3604373 *May 4, 1970Sep 14, 1971Duane E CrowleySecurity storage apparatus
US3924254 *Oct 6, 1972Dec 2, 1975Bruce Robert LAnti-intrusion alarm system
US6215397Jul 17, 1998Apr 10, 2001Lindskog Innovation AbElectrical manually portable security case for the storage of theft attractive articles with an electrical mat having at least one elongated electrically conductive wire in a substantially continuous mesh, loop or eye structure
US6400268Jul 10, 2000Jun 4, 2002Kjell LindskogElectrical manually portable security case for the storage of theft attractive articles with an electrical mat having at least one elongated electrically conductive wire in a substantially continuous mesh, loop or eye structure
U.S. Classification340/508, 340/693.1, 340/550, 109/40, 109/42, 340/693.5
International ClassificationG08B13/22
Cooperative ClassificationG08B13/22
European ClassificationG08B13/22