Patent Publication Number: US-3879726-A

Title: Audible alarm unit

Description:
United States Patent 1191 Sweany Apr. 22, 1975 [5 AUDIBLE ALARM UNIT 3.331.970 7/1967 Dundon m 310/91 3.5 .654 3 197 H h 310 8.9 [75] lnvemo sweany, Carmel 3512 1.460 6/1978 W223 310/82 73 Assigneez p R Mallory &amp; Cm Inc&#34; 3.578.995 5/1971 Massa 3l0/8.8 Indianapolis Ind 3.638.052 1/1972 Massa 310/8.2 3.700.938 10/1972 Bryant.... 3l0/9.1 [22] Filed: Oct. 9, 1973 3.716.681 2/1973 Barrow 179/110 A [21] Appl. No.: 404,453  
  Primary Examiner-John W. Caldwell Related Apphcatlon Dam Assistant Exanziner-William M. Wannisky [63] Continuation of Scr. No. 236.307. March 20. 1972. Attorney, Agent or Fj Cha w H ff abandmcd&#39; Robert F. Meyer; Donald W. Hanson [52] U.S. Cl 340/384 E; 310/9.1; 179/110 A;  
  174/5052; 174/52 R; 29/2535; 340/10 57 ST CT [51] Int. Cl. G08b 3/00 [58] Field of Search 340/384 E. 10; 310/8. 8.2, A piezoelectric transducer is carried in one of two 310/8]. 9.1. 9.2. 9.4, 8.5. 8.8; 179/110 A; compartments ofa cup-shaped housing member with a 220/21 R; 174/50, 50.52. 52 R, 52 S; printed circuit board assembly having an electrical cir- 29/25.35 cuit to energize the piezoelectric transducer carried in [56] References Cited the other compartment.  
  UNITED STATES PATENTS 7 Cl 3 D 2.967.957 1/1961 Massa 310/94 i gums AUDlIBlLE ALARM urvrr This is a continuation of application Ser. No. 236,307, filed Mar. 20, 1972, and now abandoned.  
  This invention relates to an audible alarm unit; and more particularly to a piezoelectric audible alarm unit which is contained in a low cost housing.  
  Piezoelectric transducers are being increasingly used in audible alarm units to produce audible signals from small electric currents. The transducer includes a vibrating surface which vibrates in response to electrical currents and produces the audible signal. Usually the means supplying the electrical current is carried on a printed circuit board. The transducer and the printed circuit board are carried in a suitable housing which because of strong competition in the industry should be made as low cost as possible while being neat and compact and still be able to protect the transducer and the printed circuit board from rough handling and abuse. Moreover, the number of parts to be handled in provid ing the housing with the working elements of the unit should be minimized.  
  It is therefore an object of the present invention to provide a low cost piezoelectric audible alarm unit.  
 Another object of the invention is to provide a low cost piezoelectric alarm unit including a piezoelectric transducer and a printed circuit board assembly having the electrical circuit necessary to energize the transducer, both of which are contained in a compact housing.  
  A further object of the invention is to provide a piezoelectric audible alarm unit the elements of which are contained in a housing which is relatively inexpensive, neat and compact but yet be able to protect the elements of the unit.  
  Yet still another object of the invention is to provide a piezoelectric audible alarm unit wherein a piezoelectric transducer is carried in one of two compartments of a housing with a printed circuit board assembly having an electrical circuit for energizing the transducer contained in another compartment of the housing.  
  These and other objects of the invention will be apparent from the following description taken in conjunction with the accompanying drawings wherein:  
  FIG. 1 is a cross-section in elevation of the audible alarm unit;  
  FIG/2 is a view looking at the outlet end of the unit; and  
 FIG. 3 is a view looking at the other end of the unit.  
  Generally speaking, the objects of the invention are accomplished by providing an audible alarm unit which includes a housing including a cup-shaped member having open and closed ends, first and second storage compartments, and a cover closing the open end; shelf means separating the compartments; an aperture in the closed end; a piezoelectric transducer carried in one of the compartments and having a vibrating surface exposed to the aperture; a printed circuit board assembly carried by the shelf in the other of the compartments including an electrical circuit for energizing the piezoelectric transducer; electrical terminals extending from the printed circuit board assembly out through the cover; and alarm unit mounting means carried by the housing.  
  Referring now to the drawings, an audible alarm unit includes a piezoelectric transducer 12, an electrical circuit 14 energizing the piezoelectric transducer carried by a printed circuit board 16, the printed circuit board and the piezoelectric transducer being contained in a housing 18.  
  Piezoelectric transducer 12 includes a vibrating surface 20 and electrodes 22 which causes the vibrating surface to vibrate when electrical current is applied to the electrodes. The electrical circuit 14 carried by the printed circuit board 16, and which is used to supply electrical energy tothe transducer, includes a variety of resistors 24, a transistor 26 and other electrical elements needed to energize the transducer in a predetermined manner. A more complete description of an audible alarm unit employing a piezoelectric transducer and an electric circuit to energize the transducer is described in US. Pat. No. 3,277,465 which is incorporated herein by reference. Electrical leads 28 connect the transducer to the elements 14 supplying the current to the transducer.  
  Housing 18 includes a cup-shaped member 30 having open and closed ends 32 and 34 respectively and a cover 36 substantially closingthe open. end. The housing may be fabricated from aluminum or soft steel, for example. As shown, the housing is divided into two storage compartments 38 and 40 with a shelf means 42 providing a means for separating the two. The printed circuit board which with its electrical circuit 14 is carried in compartment 38 on shelf means 42, while the piezoelectric transducer 22 is carried in compartment 40. An aperture 44 is provided in the closed end 34 of the cup-shaped member so that the vibrating surface 20 may be exposed to the surrounding area. The transducer is carried on a rib 46 which substantially surrounds the aperture 44, the transducer being bonded to the rib through a suitable adhesive 48 such as resilient silicone rubber. Vibrating surface 20 is protected from damage through a grill 50.  
  Shelf means 42 includes a rib 52 provided by the taper resulting from the difference of diameters of the two compartments. Cover 36 is maintained in fixed relation from printed circuit board 16 through a spacer means which includes a ring 5 4. A pair of electrical terminals 58 extend from the printed circuit board out through the cover 36 so that electrical power may be supplied to the unit. The alarm unit may be mounted on any suitable frame (not shown) by an alarm unit mounting means which in the present embodiment includes a ring 60 having a plurality of ears 62 extending therefrom.  
 What is claimed is:  
 1. An audible alarm unit comprising:  
 a. a housing including a cup-shaped member having open and closed ends, first and second storage compartments, and a cover closing said open end,  
 b. shelf means providing a means separating said compartments,  
 c. an aperture in said closed end providing an opening to one of said compartments, and a rib surrounding said aperture,  
 d. a piezoelectric transducer bonded to said rib and having a vibrating surface exposed to said aperture,  
 e. a printed circuit board assembly carried by said shelf in the other of said compartments including an electrical circuit for energizing said piezoelectric transducer,  
 f. electrical terminals extending from said printed circuit board assembly out through said cover,  
 g. alarm unit mounting means comprising a ring carried by said cover and a plurality of ears extending from said ring, and  
 h. spacer means carried by and disposed between said printed circuit board and said cover to maintain said printed circuit board and cover in spaced relation.  
  2. An audible alarm unit according to claim 1 wherein said shelf means includes a rib extending around the inner periphery of said cup-shaped member.  
  3. An audible alarm unit according to claim 2 wherein said first and second compartments are of different diameters and said rib is provided by a taper bewherein said-cup-shaped member is aluminum.