US2148790A - Time controlled electrical switch - Google Patents

Description

Feb. 28, 1939. F. WAGN ER ET AL r 2,143,790

' TIME CONTROLLED ELECTRICAL SWITCH Filed Aug. 12, 1936 2 Sheets-Sheet 1 14 42 15 a BWJ 21 1a In venforS 4M W W M BytluirAfforne wad/W4 Feb. 28, 1939. F. WAGNER ET AL TIME CONTROLLED ELECTRICAL SW ITCH Filed Aug. 12, 1956 2 Sheets-Sheet 2 q lnvenfors MM M By tbm-Afforne d Patented Feb. 28, 1939 2,148,790

UNITED STATES PATENT OFFICE 2,148,790 TIME CONTROLLED ELECTRICAL SWITCH Ferdinand Wagner and Ferdinand Busse, Munich, Germany, assignors to Agfa Ansco Corporation, Binghamton, N. Y., a corporation of New York Application August 12, 1936, Serial No. 95,564 In Germany August 14, 1935 7 Claims. (Cl. 20041) Our present invention relates to a time conby a falling weight. In this case the means controlled electrical switch. trolling the vacuum switch can be attached di- One of its objects is to provide an improved rectly to a rack loaded by the weight. The height time controlled electrical switch, another object is of fall of the rack may be adjusted by a cam surto provide an improved time controlled electrical face with which a control member sooner or later switch which is especially adapted for use in apcomes into contact and thereupon switches off the paratus which is required to be used in dark current. rooms, for example in photographic printing de- A vacuum switch of the usual type consists in vices. Further objects will be seen from the dean evacuated glass tube containing a stationary tailed specification following hereafter. Refercontact operated from the outside by a glass rod. ence is made to the accompanying drawings in A vacuum switch I of this type is incorporated in which a time controlled switching device, for example a Fig. 1 is a View of the apparatus with the front device controlled by a falling weight. The glass plate removed, and the weight in its upper posirod 2 operates the switch I. The extraordinary tion. small switching motions necessary to switch the Fig. 2 is a plan. printing illuminations on and off are produced Fig. 3 is a partial view of the timing device as as follows. A rack 3 is guided by a guide is the current is switched on, and loaded by a weight 4 and, when the weight falls,

Fig. 4 is a partial View as the current is switched drives a toothed wheel 6 by means of a pinion 5 ofi. which latter engages with the rack. The toothed Hitherto in nearly all time controlled devices wheel 6 operates an anchoring device 'I, 8. A for switching electrical current open contact pawl and ratchet 9, I0 enables the rack 3 to be switches have been employed. When a switch is raised without operating the anchoring device. to be used for switching on illumination for short At the upper end of the rack 3 a pin I I is provided periods of time, as is usual in modern photowhich, at the beginning of the downward move- 25 graphic printing processes, such known devices ment of the rack, bears against a bell crank lever cannot be employed since the contact surfaces of I2. The pin I i presses the lever I2 to one side the contact switch easily fuse owing to arcing, and by means of a pin I 2a causes the glass rod 2 are subjected to heavy mechanical wear and tear to break the current to the lamp. As soon, and are, furthermore, readily covered with dust. however, as the rack 3 moves downwards, the pin Uncertain conditions of operation of the switch II releases the lever I2 and it is rotated about its are the result. Mercury switches are also unpivot- 1 by Sp P e 011 the as d 2 suitable for use in time controlled switching and the switch closes the circuit to the lamp. means employed in photographic printing, since This point of time is shown in Fig. 3. they cannot be fixedly mounted and also necessi- In order to limit the interval of time between tate a long switching path. switching on and off of the current to any de- In order to enable current for illumination in sired extent, a cam plate 13 is provided, which, tophotographic printing and similar processes to be gether with a dial plate I4, is rotatable on an axle switched on and off at any desired regulable inter- I5. According as a short or a long illumination vals of time in a satisfactory manner the present time is desired, the dial plate I4 and therewith invention employs a vacuum switch with solid the cam plate I3 is rotated anti-clockwise or electrodes to efiect the switching operation. clockwise with reference to a fixed index mark. By using the vacuum switch, which is known In Fig. l the Cam plate !3 is Shown in a position per se, switching can be efiected at short intervals which gives the clock a long period of fall. A with maintained accuracy lever I6 is rotatably mounted on a pin I6a on the The switching paths necessary in vacuum rack 3. A stop I611 is fixed on the lever I6 which switches are very short, the force necessary to slides in a slot I! in the base plate I8. As soon operate the switch is extremely small, while the as the rack 3 has fallen sufiiciently far for the contact surfaces cannot become dirty. Furtherp to Strike the Cam plate l3 (See t more, if solid electrodes be used there is no limilever I6 is rotated in the direction of the arrow A tation on the orientation of the switch as is the and pres a v r rotatably m n d on a case with mercury switches. pin I922 on the base plate I8 to one side against The use of a vacuum switch with solid electhe action of a spring 20. This causes a pawl 22 trodes is particularly advantageous in phototo fall into engagement with a tooth l9a on the grap .ic printing with a timing device controlled lever I9 and with the teeth of a ratchet wheel 23 7 means for operating said switch, a weight-oper- V against the action of a spring 2|. The nose of the lever 22 presses against pin I21; and thus rotates the lever l2 in the direction of the arrow. This causes the pin in to press the glass rod 2 to one side so as to break the current to the printing lamp. The ratchet Z3 is in toothed engagement with the gear wheel 6 and thus limits the fall of the rack 3 in accordance with the adjustment of the cam plate 13. A pin 24 on the rack 3 serves to lift the pawl the tooth 19a as the rack is raised so that the apparatus can rotate freely the next time the weight falls.

What we claim is:

=1. In a photographic printing device, in combination, a vacuum switch with solid electrodes,

ated movable member, means carried by said movable member for actuating said switch-operating means at one point in the movement of said member, other means carried by said member for effecting actuation of said switch-operating means at a different point in the movement of said member, and means for varying said second point in the movement of said member where said other means carried by said member becomes effective.

2. A device as defined in claim 1, wherein said weight-operated movable member is a weight operated rack.

3. A device as defined in claim 1, wherein said weight-operated movable member is a rack and wherein the means for varying said second point in the movement of said rack is a cam.

4. In a printing device, in combination, a support, a vacuum switch having solid electrodes carried thereby, means for operating said switch, a weight-controlled rack, means carried by said rack for actuating said switch-operating means at one point in the movement of said rack, means pivoted to said support also adapted to actuate said switch operating means, other means carried by said rack for operating said pivoted means at a difierent point in the movement of said rack, and means for varying said second point in the movement of said rack where said other means carried by said rack becomes effective.

5. In a printing device, in combination, a support,

a vacuum switch having solid electrodes carried thereby, a bell crank for operating said 22 from the ratchet 23 and switch, a weight-controlled rack, a stop member carried by said rack for contacting said bell crank at one point in the movement of said rack to cause the bell crank to operate said switch, a lever pivoted to said rack, said support having a slot therein, a stop member on said lever adapted to ride in said slot as the rack is moved, a second lever pivoted to said support and carrying a tooth at the upper end thereof, an additional lever pivoted to said support above said last-named lever having a notch adapted to engage the tooth of said second lever, a stop member carried by said additional lever adapted to bear against and actuate said bell crank, a cam pivoted to said support and adapted to strike the lever carried by said rack as the rack is moved to force said lever against said second lever and thereby cause actuation of the bell crank through said additional lever, said cam being adjustabie to vary the point at which it strikes the lever carried by said rack and thus the time at which said lever becomes efiective.

6. A time controlled electrical switch comprising a rockable element for opening and closing an electric circuit, a movable Weight controlled member, adjustable cam controlling means coacting with said member for determining the time of movement thereof, and means coacting between said movable member and said rockable element for actuating the latter circuit at the beginning of movement of, said member and open said electrical circuit at the timed end of said movement.

'7. A time controlled electrical switch comprising a rockable element for opening and closing an electric circuit, a movable weight controlled to close the electrical 3 member, adjustable cam controlling means 00- acting with said member for determining the time of movement thereof, and means coacting between said movable member and said rockable element for actuating the latter to close the electrical circuit at the beginning of movement of said member and open said electrical circuit at the timed end of said movement, said means com prising a pivoted arm carried by said movable member and a pivoted member engageable with said rockable element.

FERDINAND WAGNER. FERDINAND BUSSE.

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