US2086785A - Variable alarm - Google Patents

Description

July 13, 1937. A G, THOMAs 2,086,785

VARIABLE ALARM Filed April 6, 1935 5 Sheets-Sheet l A itorney A. G. THOMAS VARIABLE ALARM July 13, 1937 Filed April 6, 1955 5 Sheets-Sheet 2 A. G. THOMAS July 13, 1937.

VARIABLE ALARM Filed April 6, 1935 5 Sheets-Sheet 5 A. G. THOMAS VARIABLE ALARM July 13, 1937.

Filed April 6, 1935 5 Sheets-Sheet 4 Inventor A Home y July 13, 1937.

A. G. THCMAs VARIABLE ALARM Filed April 6, 1935 3 o 33 I 3 0 h wax/{wad 5 Sheets-Sheet 5 Inventor Attorney Patented July 13, 1937 UNITED STATES PATENT OFFICE 6 Claims.

The present invention relates to the subject matter of application Serial Number 758,948, filed Dec. 24, 1934 and shows further variations in design to accomplish the same general result, that is to devise alarms that will begin with soft signals and which will become louder after a period of time.

An alarm that starts gently and then becomes louder is very desirable since it will not startle the sleeper as often happens with ordinary alarm clocks when loud alarms suddenly begin.

The principal object of this invention is to provide an alarm that may be incorporated in an alarm clock so that an alarm signal of varied strength or of varied character may be produced.

Another object is to provide an alarm that will be automatically set to soft signal position when the manual alarm lock is manipulated, so that when the time gears of the clock allow the alarm to sound, the signals will always be soft for an initial period.

A further object is to design variable alarm mechanism that can be economically incorporated in clocks as now made, with few changes.

Other objects will appear in the following description:

In the drawings: t

Figure 1 is a side elevation of an alarm, the hammer of which is actuated by a toothed wheel.

Figure 2 is a plan view of the construction shown in Figure 1.

Figure 3 is a side elevation, in part section, of an alarm in which the hammer is damped by a piston and cylinder.

Figure 4 is a side elevation of an alarm in which the toothed wheel actuating the hammer is adjustable with respect to the hammer arm.

Figure 5 is a side elevation of an alarm in which the speed of vibration of the hammer is varied by a movable weight sliding on the hammer arm.

Figure 6 is a side elevation, in part section, of an alarm with a soft hammer and a hard hammer.

Figure '7 is a fragmentary side elevation of an alarm that is automatically set to soft position when the alarm is locked.

Figure 8 is a side elevation of an alarm in which the speed of vibration of the hammer is regulated by an air fan which is thrown out of gear to produce faster vibrations.

Figure 9 is a side elevation of an alarm with a soft bell and a loud bell.

Figure 10 is a side elevation of an alarm with a loud bell and a soft bell pivoted so that either may be brought into contact with the hammer.

Figure 11 is a side elevation of an alarm in which the rate of vibration of the hammer is determined bya centrifugal frictional governor.

Figure 11A is a front elevation of the verge and hammer construction of Figure 11.

Figure 12 is a fragmentary side elevation of an alarm in which the inertia effect of weights is used to control the speed of vibration of the hammer.

Figure 13 is a fragmentary side elevation of an alarm in which the speed of vibration of the hammer is determined by a sliding weight on the hammer arm.

Figure 14 is a fragmentary side elevation of an alarm in which the speed of vibration of the hammer is increased by lifting a weight from the hammer arm. 7

Figure 15 is a fragmentary side elevation, in part section, of an alarm in which the rate of vibration of the hammer is regulated by friction.

Figure 16 is a plan view of a hammer arm regulated by friction.

Figure 17 is a fragmentary elevation of an alarm which is easily attached to ordinary alarm clocks. The amplitude of vibration of the hammer is regulated.

Figure 18 is a side view of a detail of Figure 17.

Figure 19 is a schematic diagram of a variable alarm suitable for electric clocks.

Figure 20 is a fragmentary side section of a detail of Figure 19. s

Figure 21 is a rear elevation of the alarm set disc of Figure 20.

Figure 22 is a back View of another alarm regulated by a piston and cylinder.

Figure 23 is a fragmentary back view of an alarm regulated by a piston and cylinder, the piston being linked to a gear.

Figure 24 is a back view of an alarm which is varied by rotating a pivoted gong with reference to the hammer.

In Figures 1 and 2, hammer I, adapted to strike bell 2, is fastened to hammer arm 3 which has bent arm 4 normally resting on the peripheral surface of toothed'wheel 5 which is rotatable on key shaft 6. Hammer arm 3 is pivoted to clock frame 8 at 'l and has arm l0 extending beyond the pivot so that pin it on looking rod l2 will depress arm l0 and therefore lift arm 4 above teeth l6 when rod i2 is depressed to lock the alarm mechanism. Coiled spring 9 normally presses arm 4 against toothed wheel 5.

Locking is accomplished by finger I4 of spring spaced closer together than small teeth I! so that in addition to being louder. the signals produced will be more frequent. The back sides of teeth I6 are approximately radial so that arm 4 will fall off suddenly and produce sharp blows. Likewise hammer is normally held slightly away from bell 2 so that the hammer I will strike bell 2 and then bounce away to prevent damping.

Toothed wheel 5 and gear 22 are fastened to sleeve 2| which is rotatable on key shaft 6, being driven by ratchet 21 when spring I8 unwinds. Shaft 6 has bearing in clock frame 8 and may be turned by key 28 to rewind spring I8 since arm 4 is lifted above teeth I6 when looking rod I2 is depressed.

Gears I9 and 23 are fastened to shaft 24 and gear 25, meshing with gear I9, is fastened to shaft 26 to which is also fastened fan 29 which, when rotating, regulates the speed of rotation of toothed wheel 5.

Therefore this alarm will first produce a series of soft signals and then loud signals.

In Figure 3 rocker 29 is vibrated by the usual toothed wheel 30 which is rotated by spring driven key shaft 32 in conjunction with gear fixed to rotatable shaft 32; gear 33 fixed to rotatable shaft 35; and gear 34 fixed to shaft 36 to which is fixed toothed wheel 38.

Link 40 is pivoted to hammer arm 3'! at 39 and to piston 42 at 4| so that vibration of hammer arm 31 reciprocates piston 42 in cylinder 43 in the bottom of which is placed valve 44 which is linked to arm 45 which is pivoted to the frame at 41. The other end of arm 45 is bent up into arm 48 which is adapted to be engaged by cam 4l' which is rotated by shaft 35. Spring 46a, attached to arm 45 and frame 49, normally keeps valve 44 closed so that air will be compressed in cylinder 43 and will leak out of small hole 50 so that the rate of vibration of hammer arm 31 will be slow, resulting in a series of infrequent gentle taps of hammer 38 on bell 48. But when shaft 35 has been rotated through a sufficient angle to cause cam 41 to strike arm 46 and lift valve 44 the resistance to movement of piston 42 will be largely eliminated and the rate of vibration and the strength of blows struck by hammer 38 will increase so that loud alarm signals will result.

In Figure 4 the general principle is the same as shown in Figures 1 and 2 except that toothed wheel 5| has teeth of uniform length and the variation in tone of bell 52 when struck by hammer 53 is achieved by lifting wheel 5| vertically, with respect to pivot 56, to lift hammer 53 away from bell 52 and therefore to produce weak signals when toothed wheel 5| is rotated and strikes arm 54 attached to hammer arm 55. Spring 51 normally holds arm 54 against wheel 5|.

When toothed wheel 5| is lowered, hammer 53 is brought nearer to bell 52 so that the signals will be louder. Toothed wheel 5| is fastened to shaft 58 which has bearing in support 59, a branch of which is pivoted to the clock frame at 6!]. Cam 6| is fastened to key shaft 62 which also has bearing in support 59. Gear 63 is fastened to shaft 58 and gear 64, meshing with gear 63, is fastened to key shaft 62. Fastened to fan shaft 61 is gear 65 which meshes with gear 64 so that fan 66 will regulate the speed of rotation of toothed wheel 5|.

Post 88 is fixed to clock frame 18 and spring 69, fastened to support 59 and frame I0, pulls support 59 down against stop pin II except when cam 6| strikes against post 68 and lifts support 59 which in turn lifts rotating toothed wheel 5| to produce soft signals. When cam 6| has been turned so that it does not strike post 68, support 59 rests against stop pin ll and toothed wheel 5| is lowered to produce loud signals. When the driving spring is fully wound cam 6| is in position to strike against post 68 so that low signals will result first.

In Figure 5 the rate of vibration and strength of blow of hammer I2 on bell I3 is varied by varying the position of flanged weight I4 which is slidable on hammer arm 16. Yoke I5 attached to arm ll serves to move weight I4 and at the same time allows vertical vibration of this weight. Arm TI is attached to threaded sleeve '18 which is moved horizontally from left to right when alarm spring 88 is allowed to rotate shaft 19. Yoke I5 prevents rotary movement of sleeve I8.

The threads on key shaft 19 are cut off near the right end to leave smooth portion 8| so that sleeve I8 can run off the threads and reach a limiting position. In this way a loud alarm will be continuously sounded after weight 14 is carried to its nearest position relative to pivot 84. When spring 89 is fully wound. weight 14 will be near hammer I2 and therefore the rate of vibra tion of hammer 12 will be slow but when weight '14 is near pivot 84 the lever arm is less and the rate of vibration will be much faster and the blows will be stronger.

Spring 82, resting against frame 83, serves to force sleeve 18 back on the threads of shaft I9 when spring is being rewound. A clutch arrangement could of course be used as indicated in previous drawings.

Toothed wheel 85 is rotated by attached gear 86 and spiral gear 81. Ratchet 88 is provided as usual so that spring 88 may be rewound without rotating toothed wheel 85.

Figure 6 shows a construction in which two hammers are used, one a soft hammer 89 and the other a hard hammer 98. Hammer 89 may be covered with leather or some soft material.

Hammers 89 and 90 are pivoted on rod I03 fastened to frame I05 and are actuated by toothed wheels 92 and 93 respectively, which in turn are rotated by gears 94 and 95. Gears 98 and 91 are fastened to sleeve 99 which is keyed to shaft IUI so that when the alarm first begins gear 98 will be in mesh with gear 94 to vibrate hammer 89 to create a soft alarm signal. As shaft |0| is rotated by spring I05 through ratchet I81, wedge I98, attached to gear 91, strikes post I04 on frame I05 and forces sleeve 99 to the left thus bringing gear 91 into mesh with gear 95 to vibrate loud hammer 90 and forcing gear 98 out of mesh with gear 94 after gears 91 and 95 have begun to mesh. Gear 98 may of course be left in mesh if desired. Spring I92 tends to force sleeve 99 toward the right. It will be seen therefore that soft hammer 89 will first strike bell 9| and then loud hammer 9D.

In Figure '7 the speed of vibration of hammer I08 is regulated in a similar manner to that of Figure 5 except that sliding weight I09 is moved by pin III on arm II2 which is pivoted to the clock frame at II3. Stops H4 and 5 are fastened on hammer arm III) which is actuated by toothed wheel III: as usual.

Bent arm H8 is frictionally connected to key shaft I I9 so that when shaft I I9 is rotated by the alarm spring, in a clockwise direction, arm I I8 strikes weight I99 and pushes it over hump I20 in hammer arm I Ill so that it slides down against stop I I5. Then the speed of vibration of hammer I08 will increase. Arm II8 will rotate until it strikes pin II! on arm II2 but shaft II8 will continue to revolve to vibrate hammer I08, since there is a slip connection between shaft H8 and arm H8.

When it is desired to cut off the alarm, pivoted arm H2 is rotated to the dotted position and in doing so pin I II forces weight I09 back to the position shown and presses down against hump 10 I20 to lock the hammer and alarm mechanism against further movement. At the same time pin IIl forces arm I I8 back to the position shown in solid lines so that the alarm is automatically reset to soft signal position when the alarm is locked. Hammer I08 strikes bell I2l a series of soft blows at slow speed before arm II8 forces weight I09 over hump I to produce loud signals. When the alarm is unlocked arm H2 is in the position shown in solid lines. The time gears of 20 the clock release the alarm at the proper time as usual. A desirable feature of this alarm is that it is automatically set to soft position when the alarm is locked.

In Figure 8 a combination fan, governor and toothed wheel actuated hammer construction is used. Hammer I23 is driven by spring I24a through gear I25 and ratchet I26 and gear I21 and toothed wheel I26. Gear I22 is slidably keyed to key shaft I29, part of which is threaded. Spring I30 normally forces gear I22 in mesh with gear I23a which serves to rotate fan I24 but when threaded sleeve I25 a is carried by rotating shaft I29 sufficiently far to the left to press gear 522 out of mesh with gear I23a the resisting effect of fan 824 is eliminated and the rate of vibration of hammer I23 increases. Sleeve I25-a is keyed to frame I26a to prevent rotation. In Figure 9 hammer I3I is moved from soft bell I32 to loud bell I33 by means of yoke I36 attached to traveling threaded sleeve I3'I. Bent arm I35 is attached to wide escapement I34 which slides across toothed wheel I38 to bring hammer I 3I into align ment with bell I33. Therefore when key shaft I3'I-a is wound hammer I3I will be opposite soft bell I32 and after a period of rotation of key shaft I3'Ia, hammer I3I will be shifted to loud bell I33.

In Figure 10 soft bell I39 and loud bell I40 are fastened to the arms of U-shaped support MI which is pivoted at I42 so that cam I43 and key shaft I44 can rock bell I40 toward hammer I45 to produce a loud tone. Bell I39 may be covered with soft material and is normally held near ham mer I45 by spring I46, stop I41 being provided.

In Figure 11 the rate of vibration of hammer I48 is regulated by fly ball governor plate I49 rubbing against friction strip I50 which is attached to threaded sleeve I5I which moves horizontally as threaded key shaft I 52 is rotated.

Hammer I48 is driven by gear I53 on key shaft I52 in usual manner. Pinion gear I54 is also meshed with gear I53 and drives gear I55 which in turn rotates pinion I56 which is freely rotatable on shaft I52 but which is held in lateral position by shoulder I51, and collar I58 attached to shaft I52 and rubbing against disc I59 which is fastened to pinion I56 and rotates with it. Fly balls I60 are attached to the pivoted links I 6| connecting laterally, and rotatably movable disc I49 which is pulled to the left against compression spring I62 when gear I56 is rotated. Therefore the further left that friction strip I50 is, the faster the fly balls must be rotated in order to reach equilibrium. Therefore if key shaft I52 is turned to wind spring I63, threaded sleeve ISI will be moved to the right until strip I50 is close to disc I49, when spring I63 is fully wound. Key I64 working in a slot in sleeve I5I prevents rotation of that sleeve. Hammer I48 is driven by gear I53 and gears I530, I 5312, and toothed wheel I530. The verge I53d attached to hammer arm I48a which is pivoted in the frame I480 by shaft I48b resting in suitable bearings, is rocked back and forth by rotating toothed wheel I530 to vibrate hammer arm I 48a in wellknown manner. Shaft H8!) is fastened to hammer arm I 48a or to verge I53d.

In Figure 13 the principle involved is the same as in Figure 7 except that slidable weight I69 is held in position by catch I10 which is pivoted to straight inclined hammer arm I1 I. The alarm signals will therefore be given slowly until cam I I2 is rotated by the alarm mechanism sufiicient lyto strike catch I10 and release weight I69 which will slide down hammer arm Ill and so reduce the effective lever arm that the rate of vibration will be greatly increased. An advantage of this construction is that the alarm continues loud after the initial soft period, without a slipping clutch arrangement. Pivoted locking arm I13 moves weight I59 back so that catch I10 holds it again, when the alarm is locked.

In Figure 14 is shown a design in which suitably guided weight I88 may be allowed to rest on hammer arm I90 and oscillate with it to reduce its rate of vibration or it may be lifted off by cam I94 and held above it by pivoted catch I89. Slot I95 in weight I68 is provided so that the hammer movement will not be impeded when catch I89 is holding weight I88 in raised position. Cam I94 is rotated by the alarm spring and associated mechanism so that Weight I88 will be lifted after a period of time. Lock bar I9I has lug I92 which strikes hammer arm I90 when the bar is depressed and lug I93 which strikes catch I89 and releases weight I98 so that the alarm will always start with slow soft signals.

In Figure 15 projection I96 on the hammer arm is rubbed by friction face I91 of sleeve I98 when catch I99 is lifted by wedge 200 on the locking rod 20I striking pivoted arm 202. Sleeve I97 is slidable on rod 206 and lock arm 2IlIa stops vibration of hammer I96 when rod 20I is lifted. Spring 203 then presses face I91 against face I96 so that friction will slow down the rate of vibration of hammer 204. When cam 205 rotates through a sufficient angle it forces sleeve I9! to the right so that it is held by catch I99 and therefore the rate of vibration of hammer 204 will increase.

In Figure 16 hammer 20'! is vibrated in the usual manner to strike bell 208. Friction pad 209 mounted to rotate with shaft 2I0, which is rotated by the key shaft, rubs against hammer 20'! or some part of the hammer mechanism and reduces the rate of vibration for a time. This reduction is arranged to take place immediately after the alarm is released by the time gears and then pad 209 is rotated out of the way so that hammer 201 strikes bell 209 harder and faster blows.

Figures 17 and 18 show a variable alarm that can be adapted to ordinary alarm clocks, with few changes in the usual alarm mechanism. Hammer arm 2 is fastened as usual to rocker or verge 2I4 to which is fastened shaft 2I2 which has suitable bearing in clock frame 2I3, being prevented from lateral movement by suitable collars or pins.

Toothed wheel 2I5, fastened to shaft 2I6, is

driven by pinion 222 which meshes with gear 223 which is fastened to rotatable shaft 228a. All of these shafts have bearing in some part of frame 213. Fastened to shaft 228a is pinion 224 which meshes with gear 225 which is loosely mounted on key shaft 228 and is rotated with this shaft, through ratchet 226, when spring 221 is allowed to rotate shaft 228. When, however, spring 221 is rewound by means of key 238, ratchet 226 allows shaft 228 to be rotatedwithout turning gear 225 and the hammer mechanism.

It is desirable to have a high gear ratio between key shaft 228 and shaft 216 so that hammer 231 will be vibrated more slowly by the spring 221. In this way the vibration noise of verge 214 and toothed wheel 215, when bell 232 is not being struck by hammer 231, will not be excessive. A further reduction in this buzzing noise, which is for the low alarm, can be obtained by placing rubber cushions between clock frame 213 and the surrounding clock casing, not shown.

Pinion 229, attached to, or integral with key shaft 228, meshes with gear 221 which is fastened to shaft 228 to which is fastened also, cam 219 which is rotated through approximately one revolution when key shaft 228 rotates through its maximum number of revolutions or from fullwound to unwound condition of spring 221. Shaft 212 is bent to form arm 211 with a further bent arm 218 arranged to strike cam 219 and so to prevent hammer 231 from striking bell 232 until the cam has been rotated through a sufficient angle. When the cam is in the position shown in Figure 18 it does not interfere with movement of arm 211 and therefore will not limit the amplitude of vibration of hammer 231. Therefore if earn 219 is so fastened to shaft 228 that when spring 221 is fully wound, it prevents hammer 231 from striking bell 232 until it is rotated through a certain angle, the alarm will first begin, when released by the time gears, as a soft buzzing sound and then will become a loud alarm when hammer 231 strikes bell 232.

Figures 19, 20 and 21 show an alarmespecially adapted to electric clocks. Line wire 251 is connected to magnetizing coil 233 through switch 252, wire 253, make-and-break contact 231, flexible vibrating arm 236 pivoted or mounted on frame 241 at 238, and through wire 239.' The other line wire 258 may be connected to coil 233 through wire 242 and through resistance 244 or through resistance 244 in parallel with low resistance wires 243 and 242.

Cam 258 with low step 256 and high step 251 is attached to disc 259 which is rotatable on shaft 268 which carries hour hand 261. Spring 263 normally presses disc 259 against pointer 262 which is attached to shaft 268. Notches 265 are provided in the raised rim 266 of disc 259 so that disc 259 may be pressed in and turned so that it can be set with reference to the numbers on disc 259, which numbers represent hours. Therefore by setting disc 259 with reference to pointer 262 which drives disc 259, the position of cam 258 may be adjusted so that step 256 will strike lug 246 on flexible strip 245 at any time desired so that contact 241 on strip 245 and contact 248 on strip 249 will be brought together.

. When this happens, buzzer coil 233 will be energized with resistance 244 in series so that there will be a soft buzz. As hour hand shaft 268 rotates, however, high step 251 will then strike lug 246 and will press flexible strip 245 and 249 over until contact 254 on strip 249 touches contact 255 to which is connected wire 243. Then there I will be a. direct connection of line 258 to coil 233 and the buzz will be very loud. The alarm will finally cease after cam 251 is rotated past lug 246 or it may be cut off by opening switch 252. While pointer 262 is shown as fitting into notches, a ratchet construction maybe used. Disc 259 passes through back casing 264 of the clock.

Unnecessary detail has been largely eliminated in this description for the sake of clarity. For instance, in most cases the manual alarm release has not been shown but it should be understood that this feature would be incorporated as usual. Likewise the release operated by the time gears has not been shown in most cases since that is usual in all alarm clocks and is not necessary for a proper understanding of my improved variable alarms.

In Figure 22 hammer 261 is fastened to hammer arm 268 which is attached to verge 269 which is pivoted at 218 in usual manner. Toothed wheel 211 which actuates verge 269 is fastened to pinion 212 and both are fixed to shaft 213 which has bearing in the frame of the clock. Meshing with pinion 212 is gear 214 attached to key shaft 215 which is rotated by the alarm spring 216 when the alarm is released by the time gears; manual sliding lock 211 having been pulled back beforehand to remove lug 218 from wedge 219 which is attached to hammer arm 268.

Clutch plate 288 which has a frictional slip 7 connection with shaft 215 has arm 281 attached to it and also arm 282. Now when looking rod 211 is pushed to the left so that lug 218 strikes wedge 219 to lock hammer arm 268, arm 283 which is integral with rod 211 will at the same time strike arm 282 and will rotate plate 288 and consequently arm 281 in counter clockwise direction until arm 282 strikes stop in 284 attached to frame 285. In this position the alarm mechanism will be set for soft, slow signals since arm 286, pivoted to frame 285 at 281, will be pulled down by spring 289 so that valve 288 will close port 298 in cylinder 291 so that piston 292 will meet with back pressure when oscillated by rod 293 linking piston 292 to hammer arm 268. Therefore bell 294 will first be struck soft blows by hammer 261 at a slow rate. Then as spring shaft 215 is rotated, friction plate 288 will rotate arm 281 in clockwise direction until it strikes inclined surface 296 of bent arm 295Whl0h is integral with pivoted lever 286, so that arm 295 will be forced down and valve 288 will be lifted to allow air to escape freely from cylinder 291. Therefore the rate of vibration of hammer 281 will speed up considerably, there being little back pressure to damp the movement. Arm 281 will rotate until it strikes stop lug 291 on arm 295. Then key shaft 215 will continue to rotate and vibrate hammer 261 since clutch 288 will slip; and the alarm will continue to produce loud signals at a fast rate until spring 216 is unwound, or until alarm lock 211 is pushed to the left to stop movement of the alarm mechanism and to set the alarm to soft signal position as previously described.

It will be seen therefore, that this alarm will always start with gentle signals and will then produce louder, faster signals after a period of time, regardless of whether the alarm spring is fully or partially wound. 1

While piston 292 is shown linked to the hammer arm 268, it is obvious that it can be linked to any of the alarm gears or other parts of the alarm mechanism.

In Figure 23 gear 298 is attached to spring driven key shaft 299 and meshes with gear 300 fastened to shaft 301. Pivoted to gear 300 at 302 is link 303 to which is pivotally attached piston 304 which may be oscillated in cylinder 305, having valve 306 as before. Attached to link 303 is hammer arm 301 to which is preferably loosely fastened hammer 308 adapted to strike bell 309 when gear 300 is rotated. Valve 306 is operated as previously described in Figure 22. This construction eliminates the toothed wheel.

In Figure 24, gong 310 is pivoted to the frame 313 at 311 so that it can be moved through an angle by moving arm 312 which is attached to gong 310 near its center. Lug 314 is fastened to the outer rim of gong 310 and is not struck by vibrating hammer 315 when arm 312 is in the position shown, being held in place by spring operated catch 319 pivoted to frame 313 at 320. Catch 319 has'lug 321 adapted to be struck by pin 322 attached to clutch plate 323, which has slipping connection with key shaft 324, so that when this shaft is rotated under influence of its driving spring, pin 322 will be rotated in clockwise direction and will strike lug 321 on catch 319 and will release arm 312 so that it will be pulled up against stop lug 325 on frame 313. Tension spring 320, attached to arm 312 and frame 313 urges arm 312 in clockwise direction.

When arm 312 is resting against stop lug 325, lug 314 is rotated so that hammer 315 will strike it so that the alarm will produce a loud signal. Alarm lock rod 321 is guided by bearings in frame 313, and arm 328, attached to rod 321, presses against toothed wheel 318 and locks it when rod 321 is pushed down. When this is done the lower part of rod 321 pushes arm 312 down so that catch 319 will hold it in the position shown. One edge of rod 321 has rack teeth 329 which mesh with pinion 330 frictionally attached to clutch plate 323 both of which are rotatable against friction on key shaft 323. When arm 328 is pulled up to unlock the alarm, rod 321 is pulled up sufilciently so that teeth 329 are out of mesh with pinion 330 so that the alarm mechanism may be rotated freely. Stop lug 331 is pivoted to frame 313 so that it turns freely to allow pin 322 to pass when this pin rotates in clockwise direction but when rod 321 is pushed down to lock the alarm, rack teeth 329 mesh with pinion 330 and turn it and pin 322 in counter clockwise direction until pin 322 strikes pivoted stop lug 331 which does not bend in this direction. Therefore each time the alarm is locked pin 322 will be set in the same position so that the alarm will produce a buzz for a period before pin 322 strikes lug 321 and releases arm 312 to produce loud signals. Likewise each time the alarm is locked, rod 321 pushes arm 312 down so that it will be held by catch 319 for an initialsoft alarm period. Since pinion 330 is frictionally attached to clutch plate 323, rod 321 may be pushed down its full travel even though pin 322 may be forced against stop lug 331.

Hammer 315 is vibrated by hammer arm 318, verge 311, toothed wheel 318, and associated gears 332, 333, 334 and 335 as usual.

Many variations of all these designs are easily possible and many combinations of the constructions may be made without departing from the essential principles involved.

What I claim is:

1. In an alarm device, a sound producing ele ment, a hammer adapted to strike said sound produiing element, spring-driven means to actuate said hammer, and resisting means continuously causing a retarding effect upon said springdriven means to cause slow vibration of said hammer until said retarding effect of said resisting means is automatically lessened by movement of said spring-driven means, to cause faster vibration of said hammer.

2. In an alarm device, a sound producing element, an oscillatory hammer arm carrying a hammer to strike said sound producing element, spring-driven means to actuate said hammer arm and said hammer, and resisting means acting upon said spring-driven means to cause said hammer arm to oscillate slowly so that said hammer will strike said sound producing element slowly at measured intervals until the resisting effect of said resisting means is automatically lessened by movement of said springdriven means, to cause faster oscillations of said hammer arm and more rapid blows of said hammer upon said sound producing element.

3. In an alarm device, a sound producing element, an oscillatory hammer arm carrying a hammer to strike said sound producing element, a toothed wheel engaging said hammer arm to oscillate said arm, spring-driven means to rotate said toothed wheel, resisting means acting upon said spring-driven means to cause said hammer to strike said sound producing element slowly until the resisting effect of said resisting means is automatically lessened by movement of said spring-driven means, so that said hammer will strike said sound producing element at a faster rate.

4. In an alarm device, a sound producing element, a hammer adapted to strike said sound producing element, hammer oscillating means, centrifugally operated means exerting a continuous braking effect upon said hammer oscillating means to cause slow strokes of said hammer upon said sound producing element, and means for automatically removing said braking effect so that said hammer will strike said sound producing element at a faster rate.

5. In an alarm device, a sound producing element, a hammer arm carrying a hammer to strike said sound producing element, a verge on said hammer arm, a rotatable toothed wheel engaging said verge on said hammer arm to vibrate said arm, means for rotating said toothed wheel, a centrifugal brake to cause slow rotation of said toothed wheel so that said hammer will strike said sound producing element at a slow rate, and means for automatically removing the effect of said brake so that said hammer will strike said sound producing element at a faster rate.

6. In an alarm device, a sound producing element, a hammer adapted to strike said sound producing element, hammer actuating means, means for creating a resisting effect in said hammer actuating means so that said hammer will strike said sound producing element slowly at intervals, said resisting effect being constantly in effect during instant until said means for creating a resisting effect is automatically by movement of said hammer actuating means so that said resisting effect will be lessened with the result that said hammer will strike said sound producing eement at a rapid rate.

ALBERT G. THOMAS.

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