US3909820A

US3909820A - Repeating alarm device

Info

Publication number: US3909820A
Application number: US442647A
Authority: US
Inventors: Rintaro Nishina
Original assignee: Tamura Electric Works Ltd
Current assignee: Tamura Electric Works Ltd
Priority date: 1974-02-14
Filing date: 1974-02-14
Publication date: 1975-09-30
Anticipated expiration: 1992-09-30

Abstract

This invention is for a repeating alarm device which has a first gear secured to a rotating shaft, a second gear freely mounted on said shaft, a contact operating cam and a heart shaped cam secured to one side of the second gear, a pivotably mounted lever and a pinion secured to said lever for engaging the first and second gears, and electric contacts arranged to be closed by the contacting operating cam at a certain time in the rotation of the second gear. At this time the second gear, which has a toothless section on its periphery will not be rotated by the pinion, and the contacts being closed an alarm sounds. In order to reset the device a pin is pushed down on the lever which engages the flat part of the heart shaped cam and rotates it together with the contact operating cam and the second gear until the toothless portion is no longer opposite the pinion, the lever is released, the pinion meshes both gears and the alarm circuit is broken.

Description

United States Patent an Nishina i I ll 3,909,820

[45} Sept. 30, 1975 l l REPEATING ALARM DEVICE [75] Inventor: Rintaro Nishina. Yonezawa. Japan l73| Assignee: Tamura Electric Works. Ltd.

Tokyo. Japan 122] Filed: Feb. [4, I974 [Zll Appl. No.: 442,647

l52| US. Cl. IMO/309.1; 340/338;325/39(1;

100/!53 LB; 200/33 B; 58/[52 B [SI] Int. Cl. 008B [/00 [St ll Field of Search 340/331, 309.1 3095.

340/3096. 32] 338. 339:2(10/l53 P. I53 LB. 30 R. 33 B. 38 B; Sit/L 1 B; 315/209 R.

[Sol References Cited UNITED STATES PATENTS 2.7l'lty907 3/l957 Harris i i v r l l i. IOU/I53 LB $027,506 3/l961 Stenhammar i. film/I53 P li'i'iimrr [ituiIiiiii'r-.lohn W, Caldwell Amt/rm! litumi'ucrWilliam M. W'annisky Arm/nor. Agent. or Firm-Roland Plottel [57] ABSTRACT This imention is for a repeating alarm deriee whieh has a first gear secured to a rotating shaft. a second gear freely mounted on said shaft, 2! Contact operating cam and a heart shaped eam secured to one side of the second gear. a pirotahl mounted lever and a pinion secured to said lever For engaging the first and seeond gears. and electric Contacts arranged to be closed by the eontaeting operating eam at a certain time in the rotation of the second gear. At this time the second gear. which has a toothless section on its periphery will not be rotated by the pinion. and the contacts heing closed an alarm sounds. In order to reset the device a pin is pushed down on the lever which engages the Hat part of the heart shaped cam and rotates it to gether with the contact operating earn and the seeond gear until the toothless portion is no longer opposite the pinion, the lever is released. the pinion meshes hoth gears and the alarm cireuit is hrol-ten.

3 Claims, 4 Drawing Figures US. Patent Sept. 30,1975 Sheet 1 of2 3,909,820

U.S. Patent Sept. 30,1975 Sheet 2 of2 3,909,820

m mik REPEATING ALARM DEVICE BACKGROUND OF THE INVENTIQN This invention relates to improvement of a repeating alarm device wherein an alarm device, for example a buzzer, is operated at a set time and operated again after a predetermined interval.

ln prior art repeating alarm devices, a leaf spring or coil spring is used and the desired delayed operation is accomplished by utilizing a slip when the spring returns to its original or free state from the compressed condition. With this construction, the length of the time delay is influenced by the manner of compressing the spring or the condition of slip,

Accordingly, it is an object of this invention to provide an improved repeating alarm device which can operate accurately without the disadvantage described above.

According to this invention, there is provided a repeating alarm device comprising a first gear secured to a motion transmission shaft, a second gear rotatably mounted on said shaft, said second gear being provided with a cam, a pivotally mounted lever, a pinion carried by said lever for engaging with said first and second gears, a heart shaped cam secured to one side of said second gear, cooperating electric contacts arranged to be closed by said cam when said second gear is rotated to a predetermined position, electric alarm means connected in series with said contacts, and operating means for rotating said lever to disengage said pinion from said first and second gears thus permitting said cam to return to a predetermined position.

DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. I is a plan view of a delay mechanism embodying the invention;

FIG. 2 is a front view of the delay meachnism;

FIG. 3 is a side view of gears and FIG. 4 is a front view thereof.

The delay mechanism shown in the accompanying drawing is mounted on the frame I ofa clock or a radio receiver and driven by a motion transmission shaft 2 which is driven at a constant speed and carries a driving gear 3 and a gear 4 provided with a heart shaped cam 5 and a contact operating cam 6 as shown in FIG. 3. Gear 3 is secured to shaft 2 whereas gear 4 is rotatable with respect to shaft 2. As shown in FIGv 4, a portion 4a of the periphery of gear 4 is not provided with gear teeth.

There is also provided a L shaped crank lever 7 which is pivoted by a pin 8 and normally biased to rotate in the clockwise direction as shown by arrow A by means of a spring 9. A pinion I0 is mounted near the lower end of one leg of crank lever 7 by means ofa pin 11 to mesh driving gear 3 and gear 4 when the lower end of the crank lever 7 engages a stop 12.

A pair of cooperating contacts 13' and 14' are carried by

leaf spring

13 and 14 with their lower ends mounted on an insulator block 15. When contacts 13' and 14' are closed an operating circuit for an alarm 17 such as a buzzer. an electronic sound producer, etc., is closed from a source 18, a timer [6 and leaf spring 13 and I4.

The alarm mechanism operates as follows:

When a push rod 19 is depressed as shown by arrow B, crank lever 7 is rotated in the counterclockwise direction as shown by arrow C to disengage pinion 10 from

gears

3 and 4. As a result, gear 4 is permitted to freely rotate about shaft 2. However, as the lower end of the upper arm of crank lever 7 is urged to engage heart shaped

cam

5 and 6 and gear 4 are rotated until the lower end 7a comes to engage flat portion 5a of the heart shaped cam 5 as shown by dotted lines in FIG. 2.

When the pushbutton I9 is pushed down, the end face 7a of the lever 7 comes in contact with a peripheral point of the heart shaped cam 5. This contact point is moved in sliding fashion along the peripheral contour of cam 5, thus rotating the gear 4 to which cam 5 is affixed.

Then, when push rod 19 is released, the crank lever 7 is rotated in the clockwise direction under the bias of spring 9 to reengage pinion 10 with

gears

3 and 4 so that the rotation of motion transmission shaft 2 is transmitted to gear 4 through gear 3 and pinion 10, thus rotating cam 6 integral with gear 4.

The purpose of cam 6 is to press leaf spring 14 to close contacts 13' and 14'. However, when the heart shaped cam 5 is brought to a predetermined position by depressing push rod 19 as above described,

contacts

13 and 14 are opened and closed by cam 6 when gear 4 is gradually rotated. At this time, pinion 10 comes to engage portion 4a of gear 4 where there is no tooth, the gear 4 and cam 6 will not be rotated further.

When push rod 19 is released cam 6 is rotated in the clockwise direction by the cooperation of pinion l0 and

gears

3 and 4 to close contacts 13 and 14' whereby alarm device 17 is operated. As above described, since according to this invention contacts 13' and 14' are controlled by a gear train and cams, the delay mechanism operates at a constant speed so that the alarm device is operated a definite interval after depression of the push rod.

While the novel alarm device is switable for use in combination with a clock, it can also be applied to a radio receiver.

What we claim is:

I. A repeating alarm device comprising a first gear secured to a mation transmission shaft, a second gear rotatably mounted on said shaft, said second gear being provided with a contact operating cam and a heart shaped cam secured to one side of said second gear, a pivotably mounted lever, a pinion carried by said lever for engaging said first and second gears, cooperating electric contacts arranged to be closed by said contact operating cam when said second gear is rotated, electric alarm means connected in series with said contacts, and operating means for rotating said lever to disengage said pinion from said first and second gears and to rotate said heart shaped cam and said second gear to a predetermined position.

2. The repeating alarm device according to claim 1 wherein said lever comprises a spring biased crank lever, said pinion is supported by one arm of said crank lever, one end of the other arm is caused to engage the flat portion of said heart shaped cam when said operating means rotates said crank lever, and said second gear has a portion not provided with any teeth.

3. The repeating alarm device according to claim 1 wherein a timer is connected in series with said contacts and said electric alarm means.

II t 1= k

Claims

1. A repeating alarm device comprising a first gear secured to a mation transmission shaft, a second gear rotatably mounted on said shaft, said second gear being provided with a contact operating cam and a heart shaped cam secured to one side of said second gear, a pivotably mounted lever, a pinion carried by said lever for engaging said first and second gears, cooperating electric contacts arranged to be closed by said contact operating cam when said second gear is rotated, electric alarm means connected in series with said contacts, and operating means for rotating said lever to disengage said pinion from said first and second gears and to rotate said heart shaped cam and said second gear to a predetermined position.