US2778418A - Preset timer - Google Patents

Description

Jan. 22, 1957 1.. J. LAVIANA 2,778,418

PRESEIT TIMER Filed June 2, 1955 2 Sheets-Sheet 1 INVENTOR. LAWRENCE a. LA V/A/VA ATTORNEYS L. J. LAVIANA Jan. 22, 1957 PRESET TIMER 2 Sheets-Sheet 2 Filed June 2, 1955 INVENTOR. LAWPENCEJ. LAM/ANA A TORNEY5 PRESET TIMER Lawrence J. Laviana, Kensington, Conn, assignor to M. H. Rhodes, Inc., Hartford, Comm, a corporation of Delaware Application June 2, 1955, Serial No 512,631

6 Claims. (Cl. 1611) This invention relates to timers, and more particularly to an improved release mechanism for controlling operation of manually windable and settable timers.

Manually windable and settable timers for controlling various types of operations are well known. With such timers, however, the operation to be controlled is initiated as soon as the setting device of the timer is moved away from its off position and before it reaches its fully set position, While the timing means does not commence to run until the setting is completed. This discrepancy introduces an error which cannot be tolerated in many operations where extremely accurate timing is desired, such as in photographic developing and printing, for example. Accordingly, one object of the present invention is to provide an improved mechanism for controlling the operation of manually windable and settable timers which positively prevents initiation of the operation controlled by the timer until setting of the timer is completed.

Another object is to provide a release mechanism for controlling the starting or manually windable and settable timers which is simplified in construction and does not appreciably increase the cost of the timer.

Another object is to provide a release controlling starting for timers of the type referred to which positively prevents both running of the clock movement and commencement of the timed operation until setting of the timer is completed.

Another object is to provide in such timers an improved release mechanism for controlling starting which insures exact synchronization between the period timed by the timer and the operation controlled by the timer.

Another object is to provide an improved mechanism for starting such timers which is convenient and easy to use, and will operate dependably for the life of the timer without requiring attention or adjustment.

Other objects will be in part obvious, and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application of which will be indicated in the appended claims.

In the drawings:

Figure 1 is a front view of a timer constructed in accordance with the present invention;

Figure 2 is a fragmentary top view of the timer of Figure 1 partially broken away to show the internal arrangement of parts with the timer in the off condition;

Figure 3 is a view similar to Figure 2 showing the position of certain of the parts when the timer is in operation;

Figure 4 is a sectional view of the structure of Figure 2 taken on the line 44 thereof; and

Figure 5 is a sectional view of the structure of Figure 3 taken on the line 55 thereof.

Referring to the drawings, and particularly Figures 1, 2 and 3, a timer of the type with which the present invention is concerned includes a casing 2 enclosing a frame including a front plate 4, a middle plate 6 and a back plate 8. The front plate 4 and middle plate 6 journal a setting shaft 10 which is the main shaft of a clock movement including a spring motor 12, a gear train, of which a portion is shown at 14, and an escapement, including an escape wheel 16 and a pallet wheel 18. The motor 12 and shaft 10 have a clutch connection permitting winding of motor 12 and setting of the timer by rotating the shaft in a clockwise direction, as viewed in Figure 1, by means of a manual setting knob 20 on the front of shaft 10, and the clock movement is arranged to drive shaft 10 counterclockwise as shown in Figure l. The front of the,

casing is provided with a numbered dial 22 with which a pointer on knob 20 cooperates to indicate the setting of the timer and the portion of the set interval remaining at any instant during running of the clock movement.

On the rear of the shaft is fixed a timing cam 24 which cooperates with an arm 26 pivotally mounted on middle plate 6 by a pin 28. The cam has a radial notch 30 which when in registry with a follower 32 on arm 26 permits the arm to be pivoted counterclockwise, as shown in Figure 5, by a spring 34 connected between the free end of the arm and the middle plate. Adjacent earn 234 is a disc 36 of slightly smaller diameter having a limited angular lost motion connection with the cam and having a notch 38 with a sloping side by means of which follower 32 may be lifted out of notch 30 when shaft it is rotated to set the timer.

011 back plate 8 is rotatably mounted a control or operating cam 48 by means of which control of a desired operation is effected by the timer. By Way of example the cam 40 is shown as arranged to control the operation of one or more electric switches, and for this purpose cam 43) has one or more nose portions 42 arranged to engage respective flexible switch contact arms 44 carrying movable contacts 46 which cooperate with respective fixed contacts 48 mounted on posts 50 secured to the back plate. The operating cam is biased counterclockwise as in Figure 4 by contact arms 44. A crank portion 52 on cam 40 cooperates with a rearwardly projecting stud 54 carried by the free end of the arm 26 to form a one-way drive for rotating the cam 40 clockwise as shown in Figure 4 when arm 26 pivots counterclockwise as shown in Figure 5.

The stud 54 retains the operating cam in the position shown in Figure 4 when the follower 32 is in notch 31 in the timing cam 24. In this position of the operating cam each of its nose portions 42 holds a flexible contact arm 44 in a position such that in the timer illustrated the associated switch contacts 46, 48 are held open. As the setting knob 20 is rotated to set the timer, however, rotation of the shaft 10 immediately cams the follower 32 out of the notch 30, thereby pivoting the arm 26 and moving stud 54 counterclockwise as viewed in Figure 4, and releasing cam 40 for immediate rotation to switch closing position by the pressure of the flexible contact arms 44.

In accordance with the invention, the timer is provided with a novel release mechanism which prevents movement of the operating cam to switch closing position until after the shaft 18 is rotated all the Way to its set position, and which insures that the operating cam will be actuated in exact synchronism with the starting of clock movement. The release mechanism comprises a latch including a bar or plunger 60 mounted for longitudinal sliding movement in the front plate 4 and middle plate 6. A compression spring 62 acting between middle plate 6 and a projecting pin 64 carried by the bar urges the bar forwardly to a position such that the pin 64 presses against one side of the pallet wheel 18. The pin thus acts as a stop preventing oscillation of the pallet wheel and thereby preventing the clock movement from running when the plunger is in its forward position. On the rearward end of the plunger is a latching finger 66 which, in the forward position of the plunger, is disposed in the path of an extension 68 on the operating cam crank 52 and thereby prevents movement of the operating cam to switch closing position.

The forward end of the plunger 6i projects forwardly of the dial face 22 and carries a fingerpiece 7% by which the plunger may be displaced rearwardly. Rearward dis-- placement of the plunger removes the latching finger 66 from obstructing relation with cam 40, thereby permitting the cam to be positioned in the normal manner according to the angular position of the arm 26 and simul taneously disengagaes the stop 64 from the clutter so that the clock movement is free to run. The plunger 65 is relieved as at 72 adjacent the latching finger to allow unobstructed movement of the operating cam counterclockwise, as viewed in Figure 4, when latching finger 66 is displaced rearward from its cam-obstructing position. When such counterclockwise rotation of the cam 40 does take place, the extension 63 of the cam moves in front of latching finger 66 and forms a shoulder over which the latching finger hooks when the fingerpiece 70 is released. This holds the plunger 69 in rearwardly displaced position and thereby prevents stop 64- from reengaging the pallet wheel while the timer is running.

The operation of the timer is believed to be readily apparent from the above description but will be summarized briefly. In the initial or off position of the timer, the parts are as shown in Figures 1, 2 and 4. The follower 32 is in the notch 30, the stud 54 holds operating cam 40 in the position shown in Figure 4, the latching finger 66 is disposed in the path of the cam extension 68, and the stop 64 is pressed against the pallet Wheel 13. The timer is set for any desired operating duration by rotating the setting knob 20 clockwise as shown in Figure 1 until its pointer registers with the proper number on dial 22. This winds the spring of the clock motor and cams follower 32 out of notch 30 so that the arm 26 pivots clockwise to a position such as shown in Figure 5, and stud 54 is withdrawn from engagement with the operating cam. This conditions the operating cam for movement counterclockwise as viewed in Figure '4 by the pressure of contact arms 44-, but such movement is pre vented by latching '66. Thus both movement of the operating cam and running of the clock movement is prevented by the release mechanism while the setting knob is being rotated from ofi 'position to the desired setting.

After the setting knob has been accurately positioned at the desired setting, the timer may be started simply by depressing the fingerpiece '79. This displaces plunger 6'!) rearwardly, unlatching operating cam 4th and disengaging stop 64 from the pallet wheel 18. In this way the movement of the operating cam which allows the switches to close occurs at the exact moment that the clock movement commences :to run so that no discrepancies can exist between the starting of timing and the starting of the operation controlled by the timer.

When the operating cam rotates to switch closing position, extension 68 moves into latching engagement with finger 66 and latches the bar in its rearward position so as to prevent stop 64 from interfering with the pallet wheel 18. The clock movement then rotates the timing cam 24 until follower 32 again falls in notch 35 whereupon arm 26 moves counterclockwise as viewed in Figure and stud 54 rotates the operating cam clockwise into the position shown in Figure 4, opening the switch contacts and terminating the operating period. Simultaneously, the cam extension 68 is withdrawn from engagement with latching finger 66 and spring 62 moves plunger 60 forward, thereby re-engaging stop with pallet wheel 18 and moving latching finger 66 back into obstructing relation with the operating cam in readiness for the next timing cycle.

Thus it may be seen that a release mechanism constructed in accordance with the invention positively prevents movement of the setting knob from initiating either running of the clock movement or movement of the operating cam. The release thereby insures that the timed period will be exactly equal in duration to that set on the dial regardless of the interval between setting and starting of the timer, as well as insuring that actuation of the operating cam will occur in exact synchronism with the starting of the clock movement so that the period timed and the operation controlled by the timer Will be exactly equal in length. The release mechanism is inexpensive, yet simplified and rugged in construction and easy to operate, and hence will operate dependably for the life of the timer without requiring attention or adjustment.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim:

1. In a timer having timing means and a control member for control-ling an operation to be timed and movable between an off position and on operating position, a re lease for synchronizing movement of the control member with starting of the timing means comprising a manually releasable latch engageable with said control member in the oif position thereof, and a stop associated with the latch simultaneously engageable with said timing means to prevent running thereof.

2. In a timer having timing means and a control member for controlling an operation to be timed and movable between an off position and an operating position, .a release for synchronizing starting of the timing means with movement of the control member to operating position comprising a latch engageable with the control member in the off position thereof to prevent movement of the control member to operating position, a spring biasing the latch to engaging position, a stop associated with the latch interferingly engageable with the timing means to prevent running thereof until the latch is released, and a surface on the latch engaged by the control member in the operating position of the control member to hold the latch in released position.

3. In a timer having timing means and a control memher for controlling an operation to be timed and movable between an off position and an operating position, a release comprising a reciprocable plunger, a laterally extending finger on the plunger, a spring biasing said plunger to a latching position such that the finger .is disposed in the path of movement of the control member from its off position "to its run position, a stop carried by the plunger engageable with the timing means to prevent running thereof when the plunger is in latching position, .a fingerpiece on the plunger for enabling manual movement of the plunger away from latching position, and a surface :on the control member arranged to hook under the finger in the run position of the control member to hold the plunger away from latching position.

4. In a timer having timing means and a control member for controlling an operation to betimed and movable between an off position and an operating position, a release for controlling starting of the timer comprising a bar reciprocable between a first position and :a second position, a latch .on the bar engageable with the control member in said first position to prevent movement thereof from oif to operating position, a stop on the bar interferingly engageable with an element of said timing means in said first position to prevent running of said timing means, a spring biasing said bar to said first position, and manual means for moving said bar to said second position.

5. In a timer having timing means and a control member for controlling an operation to be timed and movable between an ofi position and an operating position, a rclease for controlling starting of the timer comprising a bar reciprocable between a first position and a second position, a latch on the bar engageable with the control member in said first position to prevent movement thereof from off to operating position, a stop on the bar interferingly engageable with an element of said timing means in said first position to prevent running of said timing means, a spring biasing said bar to said first position, manual means for moving said bar to said second position, and a finger on said latch arranged to hook over said control member in the operating position thereof to retain said bar in said second position.

6. In a timer having timing means and a control memher for controlling an operation to be timed and movable between an off position and an operating position, a release for controlling starting of the timer comprising a bar reciprocable between a first position and a second position and having one end extending exteriorly of the timer, a latch on the bar engageable with the control member in said first position to prevent movement thereof from off to operating position, a stop on the bar interferingly engageable with an element of said timing means in said first position to prevent running of said timing means, a spring biasing said bar to said first position, a fingerpiece on said one end of said bar manually depressible to move the bar to said second position, and a finger on said latch arranged to hook over said control member in the operating position thereof to retain said bar in said second position.

References Cited in the file of this patent UNITED STATES PATENTS 2,274,635 Rhodes Mar. 3, 1942

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