US3827232A - Spring driven timer - Google Patents

Abstract

In a spring driven timer a partially transparent housing is provided for enclosing a main spring, a gear train, an escapement, and a bell-sounding hammer. A drive shaft passes through the housing, supported by a bearing on a wall of the housing. The shaft supports at one end a timing cam and a hammercocking cam, and supports at its other end a bell adapted to be sounded by said hammer and an upper case member adapted to be rotated manually for setting said timer by initially adjusting the angular position of said drive shaft. A lost motion connection between a stop lever rotatably mounted on the shaft and a stop dog secured to the shaft for rotation therewith, permits 360* rotation of the shaft during its initial adjustment.

Description

United States Patent [191 Bassett Aug.6, 1974 SPRING DRIVEN TIMER [75] Inventor: Ronald M. Bassett, Chicago, Ill.

[73] Assignee: International Register Company,

Spring Grove, Ill.

[22] Filed: Dec. 11, 1972 21 Appl. No.: 313,967

[52] U.S. Cl. 58/2l.l3 [51] Int. Cl. G04f 3/02 [58] Field of Search 58/21.]3, 22.9, 39.5

[56] References Cited UNITED STATES PATENTS l,l53,466 9/1915 Tuerk 58/21.]3

Primary Examiner-Lawrence R. Franklin Attorney, Agent, or FirmHill, Gross, Simpson, Van Santen, Steadman, OHara & Simpson l 5 7 ABSTRACT In a spring driven timer a partially transparent housing is provided for enclosing a main spring, a gear train, an escapement, and a bell-sounding hammer. A drive shaft passes through the housing, supported by a bearing on a wall of the housing. The shaft supports at one end a timing cam and a hammer-cocking cam, and supports at its other end a bell adapted to be sounded by said hammer and an upper case member adapted to be rotated manually for setting said timer by initially adjusting the angular position of said drive shaft. A lost motion connection between a stop lever rotatably mounted on the shaft and a stop dog secured to the shaft for rotation therewith, permits 360 rotation of the shaft during its initial adjustment.

4 Claims, 8 Drawing Figures PATENTEU AUG 61974 SHEET 1 OF 2 PATENTED M19 3.827. 232

sum 2 or 2 Fig. 5

SPRING DRIVEN TIMER BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spring driven timer, and more particularly to such a timer which is settable to a selected interval by initially rotating a knob, and which rings a bell at the expiration of the selected interval.

2. The Prior Art A number of spring driven timers have been developed in the prior art, in which a knob or the like is rotated to select an interval, after which an escapement is driven by a spring through a gear train to permit the knob gradually to rotate back toward its initial position. When the initial position is reached a hammer is released to ring a bell, signifying that the selected interval has expired. It is desirable to produce such spring timing mechanism as economically as possible, and for this reason to arrange the component parts of such a timer so that they are multifunctional, thereby to reduce the total number of parts in the mechanism, and to increase its efficiency of operation, while at the same time reducing its cost of manufacture.

It is also desirable to achieve the maximum accuracy possible, both in setting a selected interval and in timing out the interval. For maximum accuracy in setting an interval, the indicia representing intervals which may be selected (such as minutes, for example) should be as far apart as possible, in terms of degrees of rotation of the selected knob. Then slight errors in the initial manual adjustments of the knob are minimized. To this end, it is desirable to permit the knob to be initially set to any position within 360 of its rotation, so that the indicia are spread completely around the knob and the greatest possible angle per unit of selected time interval is provided. For the same reason, it is desirable to have the control knob as large in diameter as possible, in order to spread out the scale of selectable time intervals as much as possible. However, the use of a larger knob, all other things being equal, increases the cost of the timer.

. SUMMARY OF THE INVENTION Accordingly, it is a principal object of the present invention to provide a timer apparatus in which an internal selecting knob may be initially adjusted to any position within 360 of rotation.

Another object of the present invention is to provide a timer apparatus in which the selecting knob may be made large without increasing the cost of the apparatus.

A further object of the present invention is to provide a timer apparatus which employs the fewest possible component parts, and which therefore can be manufactured efficiently and economically.

Another object of the present invention is to provide a timer apparatus which is fully operative in any position, so that the timer may be placed in any desired attitude.

A further object of the present invention is to provide a design of housing for the drive spring so that its condition can be inspected during an intermediate step in the manufacture of the timer.

These and other objects and advantages of the present invention will become manifest upon an inspection motion between said shaft and said stop lever so as to allow 360 rotation of the shaft, a bell secured to a second end of said shaft, and a cover member secured to said second end of said shaft and rotatable therewith, said cover surrounding said bell and said housing and bearing interval-designating indicia on its outer periphery.

BRIEF DESCRIPTION OF THE DRAWINGS Reference will now be made to the accompanying drawings which:

FIG. 1 is a perspective view of a spring driven timer incorporating an illustrative embodiment of the present invention;

FIG. 2 is a vertical cross-sectional view, taken through the center of the apparatus of FIG. 1;

FIG. 3 is a horizontal cross-sectional view of the apparatus illustrated in FIG. 2, taken through the plane IIIIII;

FIG. 4 is a horizontal cross-sectional view of the apparatus illustrated in FIG. 2, taken through the plane IV-IV;

FIG. 5 is a partial vertical cross-sectional view taken through the apparatus of FIG. 1 taken through the cylindrical surface V-V shown in FIG. 3;

FIG. 6 is a plan view of the bottom of the gear housing, illustrating the timing cam and the hammercocking cam in their initial positions;

FIG. 7 is a view similar to view 6 but with the cams in a different position; and

FIG. 8 is an exploded, perspective view of the stop lever and the stop dog.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1 a perspective view of a spring wound timer 10 is illustrated. The timer 10 comprises an upper cover member 12 and a lower cover member 14, the lower cover member serving as a base of the unit, and the upper cover member being rotatable about a central vertical axis with respect to the lower cover member. The upper cover member 12 is provided with indicia or marks 16 equally spaced around the periphery thereof and which represents minutes of time to which the timer may be set with reference to an index mark 18 provided on the lower cover member 14. Numerals 20 are also provided on the upper cover member 12 to give meaning to the indicia 16.

The upper cover member is rotatable through 360 in order to set the timer for any period up to 60 minutes, and the numerals 20 representative of 5 minute intervals up to minutes duration are spaced equally around the periphery of the upper cover member 12. The timer 10 is set by rotating the upper cover 12 until the index 18 is aligned with the indicia l6 corresponding to a selected time interval. Subsequently the time remaining before the expiration of the selected interval is continuously indicated by the indicia 16 adjacent the index mark 18.

FIGS. 2 through illustrate the manner in which the various components of the timer are assembled. The gear train of the timer is maintained in position between an upper frame plate 22 and a lower frame plate 24. A transparent plastic housing cover 26 encloses a space 27 above the upper frame plate 22, and four legs 28, which are formed integrally with the housing cover 26, serve to support the frame plates 22 and 24 in fixed relation to the housing cover 26. The main spring 30 is disposed above the upper frame plate 22, within the space 27 enclosed by the cover 26. The cover 26 has an upper surface 32 and a peripheral sidewall 34 surrounding the space 27. The shape of the cover 26 is elongated, with the wall 34 having straight side portions 36 and arcuate end portions 38. The side portions 36 overlie the upper frame plate 22, to maintain it in spaced parallel relation with the upper surface 32, and the end portions 38 are juxtaposed with the edge of the circular upper frame plate 22, and heat staked to form a lip 40 below opposed sections of the frame plate 22 to maintain it in position relative to the upper surface 32. The lower frame plate 24 is maintained in position by virtue of being trapped between the lower ends of the legs 28 and a surface 42 provided within the lower cover member 14. A pair of screws 44 secure two legs 28 to the lower cover member 14, while another pair of screws 45 secure the other two legs 28 to the lower frame plate 24.

The gear train is mounted between the two frame plates 22 and 24 in conventional fashion, and the main spring 30 which is maintained in coiled relation within the space 27 has one end thereof engaged in a notch 46 within the drive shaft 48, and another end hooked about the end of an interior wall 50 of the housing cover 26. The wall 50 forms a circular loop which encircles the spring 30 and holds it in place during assembly. The spring 30 is pre-wound approximately three turns prior to assembly so that there is a substantial torque constantly conveyed to the shaft 48. The fact that the housing 26 is transparent aids in the assembly of the timer, as the position and condition of the spring may be inspected until a bell 56 is placed in position.

The main bearing 52 is supported within an aperture disposed in the housing cover 26 and a boss 54' surrounds the aperture in which the bearing is located and projects upwardly'from the upper surface 32, to support the central portion of the bell 56. The bell 56 has a U-shaped cross-section and surrounds the housing cover 26, the spring 30, and the gear train supported between the plates 22 and 24.

The main bearing 52 has a central aperture which receives the shaft 48, the central aperture having a counterbore at the lower portion thereof, and the shaft 48 being provided with an enlarged portion 53 joining with the upper portion 55 of the shaft by a shoulder 54 located in juxtaposition with the shoulder formed at the end of the counterbore of the bearing 52. A bowed E- ring 56 is disposed in an annular notch surrounding the outside of the bearing 52 and functions to urge the bearing 52 upwardly relative to the housing cover 26, to take up axial play within the bearing 52, and to maintain the bell 56 tightly engaged with the housing cover 26.

the frame plates 22 and 24 and the cover 26. The gear train is disposed between the frame plates 22 and 24 and is connected to the enlarged portion 53 of the shaft 48, by means of a main drive gear 58, which encircles the shaft 48 and is adapted for rotation about the shaft 48. The gear 58 is in engagement with a gear 60 secured coaxially to a larger gear 62. The gear 62 is in engagement with a gear 64 which is secured coaxially to a larger gear 66. in similar fashion, the gear 66 is in engagement with gear 68 which is connected for rotation with a larger gear 70. The larger gear 70 is in engagement with a pinion 72, which bears a saw toothed escapement ratchet wheel 73, forming a part of an escapement mechanism 74. As a result of the action of the spring 30 urging the shaft 48 to rotate back toward its initial position, all of the gears 60-72 are urged to rotate, but the action of the escapement 74 limits the speed of rotation of the members of the gear train in the manner well understood by those skilled in the art. The escapement 74 serves to control the precise speed of the gear train, so that the rotation of the shaft 48 back to its initial condition takes place at a constant angular velocity.

The escapement 74 comprises, in addition to the ratchet wheel 73, a pawl 71 having a pair of dogs 75 for alternately engaging teeth of the ratchet wheel 73. The pawl is mounted for oscillating rotation on a shaft 65, supported between the plates 22 and 24, and a plurality of lugs 77 grip a weighted bar 79, which is provided to add mass to the pawl 71. Three of the lugs 77 are disposed within a centrally located slot in the bar 79, and two others engage the side edges of the bar. The pawl 71 is formed of plastic material, and the lugs 77 are heat staked to retain the bar 79 firmly in position.

The various gears 60-72 are supported for rotation on shafts which are engaged in aligned apertures in the two frame plates 22 and 24.

The gear 58 is connected to the shaft 48 by means of a clutch which will now be described. The shaft 48 has a shoulder 76 and a washer 78 is in engagement between the shoulder 76 and the gear 58. A second washer 80 is disposed below the gear 58 and a resilient member 82 which functions as a spring clutch is disposed on the shaft 48 above the washer 80. The washer 80 and the resilient member 82 have rectangular apertures which are adapted to receive a rectangular crosssection portion 84 of the shaft 48, thereby keying the resilient member 82 to the shaft for rotation therewith. The washer 80 is fixed firmly co-rotatably to the shaft 48 and a projection or dog 86 projects radially outwardly from the remainder of the washer 80. The dog 86 functions as a stop dog, as described below. The resilient member 82, which is keyed to the shaft 48, exerts a sufficient force acting on the gear 58 so as to prevent the shaft 48 from overriding the gear 58, as the latter slowly rotates by the action of the escapement 74. The force is low enough, however, so as to allow the shaft 48 to slip relative to the gear 58 as the shaft is initially rotated to select a time interval.

The stop dog 86 cooperates with a stop lever 88, which extends upwardly through an aperture 90 provided in the lower frame plate 24. The stop lever 88 is integrally connected with a washer 92 which is mounted for rotation about a lower terminal portion 94 of the shaft 48 which lies just below the rectangular cross-section portion 84. Accordingly,'the stop lever 88 is adapted for free oscillatory rotation relative to the shaft 48 within the limts of the aperture 90. The size of the aperture 90 is selected to permit 360 rotation of the shaft 48, such rotation being limited in both directions by engagement of the dog 86 against one side or the other of the stop lever 88. The angular extent of the aperture 90 is, therefore, approximately equal to the angular extent of the dog 86, plus twice the thickness of the lever 88.

The portion 94 of the shaft 48 is received in a circular aperture 95 in the frame plate 24.

A hub 96 is secured to the bottom of the shaft 48, and a hammer-cocking cam 98 is fixed to the hub 96 for rotation therewith and with the shaft 48. A timing cam 100 is supported on the hub for free rotation thereabout, between the hammer-cocking cam 98 and a flange 101 of the hub 96. The function of the hammercocking cam 98 is to cock a hammer arrangement, while the function of the timing cam 100 is to permit release of the hammer at the proper time, after the expiration of the selected timing interval.

A bellcrank 102 is mounted for rotation relative to the lower frame plate 24 on a stud 104. The bellcrank 102 has secured to it a cam follower pin 106 which extends downwardly through an aperture 108 provided in the lower frame plate 24 and is adapted to bear on the periphery of the timing cam 100.

A spring 120 is interconnected between an arm 122 of the bellcrank 102, and an aperture 124 provided in the lower frame plate 24. It urges the bellcrank 102 in a counterclockwise direction (as viewed in FIGS. 6 and 7), but normally the crank 102 is prevented from rotating by virtue of the follower pin 106 bearing against the periphery of the timing cam 100. When a notch 118 of the timing cam 100 is aligned in a position shown in FIG. 6, the follower pin 106 bears against the end of the notch 118, as illustrated in FIG. 6. When an interval has been selected and the timer is operating, the follower pin engages a circular portion of the timing cam 100 and the bellcrank assumes the position illustrated in FIG. 7.

At the end of the selected interval, the notch 118 again becomes aligned with the pin 106 and the bellcrank 102 is quickly rotated to the position of FIG. 6. As the bellcrank 102 rotates, a foot 126 supported thereon engages a hammer 128 supported on a stud 130 extending between the upper and lower frame plates 22 and 24. A spring 132 is wound about the stud 130 and has one end hooked around the hammer 128 and the other end trapped behind one of the legs 28, to maintain the hammer 128 rotated fully in its counterclockwise direction (as seen in FIG. 7) against the foot 126. When the bellcrank 102 rotates in a counterclockwise direction, the foot 126 bears against the hammer 128, urging it in a clockwise direction, and causing it to rotate about its stud 130 sharply against the inner surface of the bell 56. In this manner the bell 56 is caused to sound when the timing cam 100 has reached the position illustrated in FIG. 6. In this position, the shaft 48 has been rotated fully to its extreme clockwise position (as viewed in FIG. 6), where rotation is stopped by engagement of the stop lever 88 against the stop dog 86.

The timing cam is constrained to rotate with the shaft 48 by virtue of the interconnection between the hammer cocking cam 98 and a stud disposed on the surface of the timing cam 100. The stud 110 is interposed between two limiting fingers 112 and 114 on the hammer-cocking cam 98, so that as long as the stud 110 is adjacent one of the fingers 112 and 114, the timing cam 100 is constrained to rotate with the cam 98 in the direction which urges the limit finger into closer engagement with the stud 110.

The hammer-cocking cam 98 has an inclined cam surface 116 adapted to bear on the follower pin 106 when the shaft 48 is initially rotated to select a timing interval, thereby to cam the pin 106 out of engagement with the notch 118.

When the upper cover member 12 and the shaft 48 are rotated to set a selected timing interval, the hammer-cocking cam 98 is rotated in a counterclockwise direction (as viewed in FIG. 6) so that the cam surface 116 forces the follower pin 106 outwardly. The timing cam 100 is prevented from rotating during this period because the follower pin 106 is in engagement with one of the sidewalls of the notch 118. By the time the limit finger 112 reaches the stud 110, however, the follower pin 106 has been cammed outwardly beyond the outer surface of the timing cam 100, so that the timing cam is then rotated by means of the limit finger 112 bearing against the stud 110. This occurs during the first few degrees of rotation of the upper cover member 12, and afterwards, the timing cam is rotated with the cam 98 as far as necessary to select the appropriate time interval. Then the upper cover member is released and the spring 30 is effective to return the shaft 48 and the upper cover member 12 to their initial positions, under the control of the gear train and the escapement, rotating the shaft 48 in a clockwise direction (as viewed in FIGS. 6 and 7). The timing cam 100 is initially prevented from rotating because of the frictional force resulting from the follower pin 106 bearing against its periphery, but when the finger 114 engages the stud 110, the friction between the cam 100 and the following pin 106 is overcome and the timing cam 100 is forced to rotate with the cam 98. This pause in the rotation of the timing cam 100 is for the same angle of rotation of the shaft 48 as during cooking of the hammer, and therefore does not affect the accuracy of the timer. Rotation of the cam 100 continues until the notch 118 reaches the position illustrated in FIG. 6, whereupon the pin 106 falls into the notch 118 and causes the hammer 128 to strike the bell 56.

It will be seen from the foregoing description that the timer described above accomplishes the function of permitting 360 rotation of the cover member 12 in order to set a selected time period for the timer, and, as the indicia are located on the extreme periphery of the upper cover member 12, their angular separation is a maximum, resulting in the maximum accuracy of repeatability of time interval settings. Economy is achieved in the present apparatus by enabling the upper cover member 12 to doube as a cover and as a knob. There is, therefore, no need for a separate interval-selecting knob.

The embodiment described above requires only a single main bearing 52, rather than the conventional arrangement in which two spaced bearings are required. Axial alignment of the shaft 48 is assured because the flange 101 of the hub 98 is spaced just far enough to accomodate the thickness of the stop lever washer 92 and the thickness of the lower frame plate 24. The follower pin 106 bearing heavily on the timing cam 100 prevents any lateral play in the mechanism.

Because of the spring 132, which keeps the hammer 128 against the foot 126, the timer apparatus may assume any attitude and the hammer 128 remains operative to sound the bell. Preferably the flat outer surface of the lower cover member 14 is provided with an aperture to accomodate a nail head or a screw head when the timer is to be wall-mounted.

What is claimed is:

1. In a spring driven timer which is manually settable to select a time interval: an upper inverted cup-shaped cover having means centrally therein securing it to the top of a vertically extending shaft; a base member having a housing cover member mounted thereon and defining a mechanism space above said base member and below said housing cover member; timer mechanism comprising spaced upper and lower frame plates supporting a timer gear train, the upper plate being mounted on said housing cover member and said lower plate being mounted on said base member; said shaft extending downwardly through and being journaled in said housing cover member and in said lower plate and having a lower terminal portion extending below said lower plate into a space within said base below said lower plate; a gear mounted corotatably on said shaft in limited spaced relation above said lower plate and coupled with said gear train; a main spring coiled about said shaft above said upper plate and anchored at one end to said shaft and at its opposite end to said housing cover member; a bell carried by said housing cover member outside of said mechanism space; means for sounding said bell in one rotary position of said shaft and including actuating cam structure carried by the lower terminal portion of said shaft below said lower plate and effecting releasable coupling with a bell striker and actuator mounted on said lower plate; and means for limiting rotation of said shaft to about 360 during manual setting of the timer by rotation of said shaft through said upper cover and including a first limit member corotatably secured to said shaft between said gear and said housing cover member and a second limit member comprising a plate mounted about said shaft below said lower plate and above said actuating cam structure, said second limit member having a stop lever projecting upwardly through an aperturein said lower plate and being engageable by a stop dog on said first limit member, said aperture being of a width to limit movement of said lever in either rotary direction to about equal the angular extent of said dog plus twice the thickness of the lever whereby to permit the 360 rotation of the shaft.

2. A timer according to claim 1, wherein said upper cover has an annular generally vertically extending periphery carrying interval signifying indicia, and said base member has an index reference mark with respect to which said indicia are settable by turning of said upper cover member.

3. A timer according to claim 1, wherein said housing cover member is of transparent plastic and permits the position and condition of said main spring to be inspected therethrough.

4. A timer according to claim 3, said bell comprising a U-shaped inverted cup-shaped member which surrounds said housing cover member and the timer mechanism.

Claims (4)

1. In a spring driven timer which is manually settable to select a time interval: an upper inverted cup-shaped cover having means centrally therein securing it to the top of a vertically extending shaft; a base member having a housing cover member mounted thereon and defining a mechanism space above said base member and below said housing cover member; timer mechanism comprising spaced upper and lower frame plates supporting a timer gear train, the upper plate being mounted on said housing cover member and said lower plate being mounted on said base member; said shaft extending downwardly through and being journaled in said housing cover member and in said lower plate and having a lower terminal portion extending below said lower plate into a space within said base below said lower plate; a gear mounted corotatably on said shaft in limited spaced relation above said lower plate and coupled with said gear train; a main spring coiled about said shaft above said upper plate and anchored at one end to said shaft and at its opposite end to said housing cover member; a bell carried by said housing cover member outside of said mechanism space; means for sounding said bell in one rotary position of said shaft and including actuating cam structure carried by the lower terminal portion of said shaft below said lower plate and effecting releasable coupling with a bell striker and actuator mounted on said lower plate; and means for limiting rotation of said shaft to about 360* during manual setting of the timer by rotation of said shaft through said upper cover and including a first limit member corotatably secured to said shaft between said gear and said housing cover member and a second limit member comprising a plate mounted about said shaft below said lower plate and above said actuating cam structure, said second limit member having a stop lever projecting upwardly through an aperture in said lower plAte and being engageable by a stop dog on said first limit member, said aperture being of a width to limit movement of said lever in either rotary direction to about equal the angular extent of said dog plus twice the thickness of the lever whereby to permit the 360* rotation of the shaft.

2. A timer according to claim 1, wherein said upper cover has an annular generally vertically extending periphery carrying interval signifying indicia, and said base member has an index reference mark with respect to which said indicia are settable by turning of said upper cover member.

3. A timer according to claim 1, wherein said housing cover member is of transparent plastic and permits the position and condition of said main spring to be inspected therethrough.

4. A timer according to claim 3, said bell comprising a U-shaped inverted cup-shaped member which surrounds said housing cover member and the timer mechanism.

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