H. F. STREBEL El AL FIRE ALARM BOX RETENTION DEVICE Filed May 11, 1936 2 Sheets-Sheet 1 gfohn R'fies Henry F fiirebel INVENTORS:
ATTORNEY5 'Oct- 3 H. F. STREBEL ET AL 2,175,976
FIRE ALARM BOX RETENTION DEVICE John [Cries Hen/ y]? Sirebel INVENTORS ATTOI-QNEYS Patented Oct. 10, 1939 UNITED STATES FIRE ALARM BOX RETENTION DEVICE Henry F. Strebel, Garden City, and John Kries,
I Glendale, N. Y.
Application May 11, 1936, Serial No. 79,192
The present invention relates to fire alarm equipment and more particularly to devices associated with a fire alarm box and adapted to retain the operator of an alarm until the arrival of the fire apparatus.
The general object of the invention is to obviate the occurrence of false alarms by providing means operated coactively with the sending of an alarm, by which the operator is retained.
Another object of the invention resides in providing a fire alarm retention device of simple and rugged construction in combination with an alarm system control, the operation of which will actuate the retention device so that the arm of the operator is engaged until released by an authorized person.
The invention will be fully and comprehensively understood from a consideration of the following detailed description when read in connection with the accompanying drawings which form part of the application.
In the drawings:
Fig. 1 is a perspective view of a typical fire alarm box equipped with the retention device preparatory to sending an alarm.
Fig. 2 is a fragmentary perspective view of the fire alarm box after the alarm has been sounded.
Fig. 3 is a rear elevational view of the fire alarm box, portions of the casing being broken away to illustrate the mechanism comprising the retention device and the alarm control apparatus.
Fig. 4 is a transverse sectional view through the alarm box taken on the plane 4-4 of Fig. 3; and
Fig. 5 is a fragmentary sectional view taken on the plane 5-5 of Fig. 3, and illustrating the means for locking the actuating mechanism against reverse operation.
Figure 6 is a detailed view of the bevelled gears for operating the device and illustrating a preferred means of distorting one of the gear teeth to provide a friction means.
Reference is now directed to the drawings for a more detailed description thereof, in which the numeral 6 indicates a typical fire alarm box provided for housing a fire alarm sounding equipment. Preferably in the front panel of the box 6 is formed an aperture 1 fitted with a suitable door 8 to provide a closure for same.
The aperture 1 is of a minimum size to admit the hand of an operator, and has associated therewith a sliding member or gate 9 arranged to form a partial closure for the aperture 1. The gate 9 is slidably retained on the inner surface of the box 6 by a suitable means such as the guide- Ways la so that the gate 9 upon being actuated will move across the aperture 1 and thus diminish the free area thereof.
The gate 9 is provided with an inwardly extending box 9a so as to prevent the grasping of the lower edge of the gate 9 after same has been lowered slightly by the'initial movement of the operating mechanism, hereinafter described. Were it possible for the operator to grasp the gate 9, the sounding of an alarm could be effected by withdrawing the operators hand and further operatingthe mechanism by a downward pull on the gate 9. The actuation of the gate 9 is accomplished by means comprising the gear rack l secured to the gate 9 and arranged to mesh with a gear I l affixed to a rotatable shaft l2, the shaft l2 being journalled in bearings 13.
As afore indicated the primary function of the apparatus is to operate a fire alarm switch or other alarm control element coactively with the actuation ofthe retention device comprising the gate 9. To accomplish this a rod I4 is secured to the gate 9 to project longitudinally from same and has its free end flexibly engaged to a rockable lever arm IS, the latter being swingably mounted on the stud l6 secured to a wall of the box 6. Suitably-arranged on thefree end of the lever arm I is a-contact plate l8, the same being electrically insulated from the arm by the insulator IS. The numeral 20 indicates a pair of electricalterminals which form part of the alarm sounding equipment,- andto which the wires forming the alarm circuit may be connected. The contacts 20 are supported on a suitable bracket 2! being insulated from the same, and so disposed that when the gate 9 is lowered the contact plate l8 engaging the contacts 20 completes the alarm circuit, this position of the arm l5 being shown in phantom.
It will be seen from the foregoing that the lowering of the gate 9 to constrict the aperture 7 and coactively close the alarm circuit may be accomplished by the rotation-of the shaft I2 in the. direction indicated by the arrow in Fig. 4. The rotation of the shaft l2 may be accomplished by suitable means such as thatcomprising the bevel gear 22 carried on the shaft l2 and arranged to mesh with a second gear 23. The gear 23 is secured to a shaft 24 journalled in a bracket 25, the opposite end of the shaft 24 being equipped with a suitable operating device such as the hand wheel 26.
It will be seen that the rotation of .the hand wheel 26 will cause the lowering of the gate 9 until same engages the wrist of the operator and, coactively the alarm circuit is closed by raising the plate l8 into contact with the terminals 21!.
In order to defeat an attempt of the operator to release himself by rotating the hand wheel 26 in the reverse direction, a locking mechanism 21 is provided as shown more clearly in Fig. 5. To the shaft I2 is fixed a ratchet wheel 28, the same being contained in a full sided housing 29. A weighted pawl 30 being pivotally mounted is disposed to engage the teeth of the ratchet wheel 28 to prevent the actuation of the shaft I2 in a reverse direction.
To provide authorized access to the interior of the box 6, a lock equipped door 3| is provided thereon. After the arrival of the fire apparatus an official may release the sender of an alarm by opening the door 3| through which the pawl 30 may be released from the ratchet wheel 28 by raising the pawl 39 by means of a lever 32 pivoted on a stud 33, the lever 32 being operatively connected to the pawl 30 by a rod 34. The rod 34 is loosely coupled to the pawl 30 by a slip joint 35 so as to permit the free movement of the pawl 30, independent of the lever 32. To assure that the gate 9 be lowered entirely until the wrist of the operator is engaged, the gate 9 after its initial movement is lowered by gravity, and is accordingly weighted as indicated at 39. Although the operator may release the hand wheel 26 after the initial operation, the sounding of the alarm and the retention of the operator will be effected since the gate 9 will be lowered by gravity, and thus close the alarm circuit. To hold the gate 9 in its raised position until after the initial movement of same has been effected, suitable frictional means may be employed on the shaft I2. It is preferred to accomplish this effect by enlarging or otherwise deforming one or more of the teeth of either of the gears 22 or 23, which teeth are in mesh as the gate 9 is in its uppermost position. For purposes of illustration, Figure 6 discloses a deformed gear tooth 31, which tooth when in mesh with the gear 22 will eiTect suitable friction means for holding the gate 9 in its raised position until after the initial movement of same has been effected. It is to be understood, however, that more than one tooth can be distorted should it be necessary to hold the gate in raised position. Thus a sufficient amount of power applied to the hand wheel 26 is required to overcome the friction effected by the distorted gear tooth 31 until the initial movement of the gate 9 is effected, after which the weight 36 functions to complete the operation of the device independent of the mechanism operating means.
It is to be understood that this improvement is capable of extended application and is not confined to the exact showing of the drawings nor to the precise construction described and, therefore, such changes and modifications may be made therein as do not affect the spirit of the invention nor exceed the scope thereof as expressed in the appended claims.
What is claimed as new is:
1. A fire alarm apparatus of the type described comprising a casing having an aperture formed in a side thereof adapted to permit passage of a human hand therethrough, means for reducing the area of said aperture without entirely closing same whereby passage of a human hand therethrough can be controlled, said means comprising a gate positioned within said casing adjacent but normally above said opening and slidable in guideways afiixed to parts of said casing, said gate including a box extending inwardly therefrom and upwardly from the lower edge thereof and terminating adjacent the opposite wall of said casing, a weighted element within said box fer moving said gate by gravity over said opening, means for holding the gate in its raised position, comprising a rack on said gate, a pinion engaging the rack, a gear train operatively connected to the pinion, one or more teeth of a gear in said train being deformed to prevent interaction of the gears for rotation of the pinion, means within the casing to force interaction of said deformed gear and train, whereby downward movement of the gate may be initiated, said means comprising a hand wheel operatively connected to the gear train, means actuated by downward movement of said gate for signalling an alarm, means for precluding unauthorized lifting and counter-movement of said gate comprising a ratchet wheel and pawl associated with and simultaneously actuable by said gear whereby upward movement of the gate is prevented While said pawl and ratchet are in engagement, and means accessible only through a manually locked door in said casing for releasing said ratchet, thereby permitting raising of the gate.
2. A fire alarm apparatus of the type described comprising a casing having an aperture formed in a side thereof adapted to permit passage of a human hand therethrough, means for diminishing the size of said aperture without entirely closing same whereby passage of a human hand therethrough can be controlled, said means comprising a gate positioned within said casing adjacent but normally above said opening and slidable in guideways aifixed to parts of said casing, said gate being weighted so as to move by gravity over said opening, means for holding the gate in its raised position, comprising a rack on said gate, a pinion engaging the rack, a gear train operatively connected to the pinion, one or more teeth of a gear in said train being deformed to prevent interaction of the gears for rotation of the pinion, means within the casing to force interaction of said deformed gear and train, whereby downward movement of the gate may be initiated, said means comprising a hand wheel operatively connected to the gear train, means actuated by downward movement of said gate for signalling an alarm, means for precluding unauthorized lifting and counter-movement of said gate comprising a ratchet wheel and pawl associated with and simultaneously actuable by said gear whereby upward movement of the gate is prevented while said pawl and ratchet are in engagement, and means accessible only through a manually locked door in said casing for releasing said ratchet, thereby permitting raising of the gate.
HENRY F. STREBEL. JOHN KRIES.