US1794888A - Automatic switch - Google Patents

Description

March 3, 1931. J. ERICKSON. 157945888 AUTOMATIC SWITCH Original Filed March 14, 1925 Juhn Erlcksun mama Mar. 3, 1931 NITED sures PATENT orrrcs :omr memoir, or cmcaco, more, assrenoa', a! m: marinara, 'ro

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The present invention relates in' neral to automatic switches, although certam details are not confined specifically thereto; and has for its object the provision of certain mechanical improvements tending to make such switches more easily adjustable, together with bank of contacts is adapted to be ciated parts.

the addition of other desirable features which tend to make such switches more rugged and durable.-

The invention is illustrated in the accompanyin drawings, in which Fig. 1 is a side view 0 a switch of the same general ty as that described in the U. S. Patent #1,10' 1 53, granted August 11, 1914 toClement, being, however, of the particular type shown and described in Automatic Telephone Practice, third edition, by Harry E. Hershey. Figure 2 is a front view of the switch shown in ig. 1. In order to avoid complicating the drawing the bank contact assembly and the drivi magnet interrupter contacts have been omitted in Fig. 2. Flgure 3 is an end view of the driving magnet and asso- Referring now articularly to Fig. 1, the bank of contacts own'therein is indicated generally by the referenoenumeral 2. This over by the double ended wiper 4 and 1s so arranged with respect to the wiper that as one arm of the latter a 'ofi the last bank'con tact in rotating, the other wiper arm comes into enga mcnt with the first contact. In this 0 switch, instead of providing a common plate in the bank for each wiper with which one of the arms of that wiper is in constant engagement, a brush extends to and makes continuous contact with each of the wipers. The terminal of the brush that makes contact with the wiper 4 is the terminal 11. r

The wiper 4, being a test wiper, has its two contact tips flattened out so as to be able to come into engagement with a second contact before itis out of engagement with the one from which it is The remaining wipers 5-7, inclusive,,Fig. 2, however, being line wipers, have their t ps so shape?! that onlyone contactat a timexis engaged by one of these wipers. The ratchet wheel 13 and is forced to the right against the tension of the spring 21.- The pawl 17 ,carried by the armature 19, 5. caused to engage another tooth in the ratchet wheel 13 by the awl spring 18. when the said magnet 10 dbe ergizes, the spring 21 draws the armature 19 and likewise the pawl 17 to their former position, at which time the armature 19 is restmg against the eccentrically adjustable back stop 31, as can be seen most clearly in Fig. 2. The pawl 17, in returning to its normal pofition, advances the wipers 47, inclusive, into engagement with the next set of contacts. This operation may be repeated as often as desire v 1 It was pointed out above that the eccentrically pivoted backstop 31 limitsthe backward stroke of the armature 19. The forward stroke of the armature 19, it may be stated,

is limited by the soft ironpole piece 29, Figs.

is attached to the switch mechanism by the screws o" and 6'. The set screw 7' is rovi ded for the purpose of enabling the swltch wipers to be accurately centered on the bank contacts by adjusting the bank frame 3 so that it is closer to or farther from the switch frame 8. The longitudinal adjustment between the frames 3 andfi is made ossible owing to the fact that the holein t e set screw 7' through which the screw 6 passes is purposely made very much larger than the screw 5' passes through a slot in the frame 8, which slot can be seen in Fig. 2. p

One of the features of the invention relates to the improved pawl 17 together with 6, and owing also to the fact that the screw its bearing and the way in which it is operated upon by the pawl spring 18 As can be readily seen by inspecting Figs. 1 and 2, the pawl 17 is cut from a piece of heavy sheet metal andis bent in the shape of an inverted U and retains this shape along its length almost to the tip, thereby giving it the neces sary'stifi'ness and strength. Referring to the pawl spring 18, one end of this spring passes through a hole in the end of the armature 19, while the other end passes through a hole (not shown) in the pawl-17. This spring, it will be noted, while pulling the pawl 17 in such a direction as' to cause it to lie snugly against the ratchet wheel 13, also pulls the pawl 17 back snugly against the armature 19 so that'in' case the bearing has a small amount of play, the pawl 17 is not hammered back and forth as the armature 19 vibrates, as would be the case if the spring 18 were so positioned as to merely pull the pawl 17 upward instead of upward and backward as it does. The armature 19 is provided with a bushing 32 (Fig. 2), which gives extra bearing surface for the hollow bearing pin 15 which- "passes through the pawl 17 and the aforesaid bushing 32, and-which is spread at the ends to hold it in place.

In order that the tension on the armature spring 21 be readily adjustable, the adjusting member 22 is slidably mounted on the switch frame 8 by the machine bolt 23, which passes through the slot 24, and the pivot pin 25. This pivot pin 25, therefore, serves the double purpose of pivoting the armature 19 and furnishing a back stop for the adjusting member 22, which would otherwise be rotated around the machine screw 23 by the spring 21.

In order that the further utility of the slidable adjusting member 22 be appreciated,

' it may be pointed out that the switches are mounted side 'by side and close together in the position of Fig. 2. When the switch is mounted in this position, the tension of the spring 22 is adjusted by first loosening the bolt 23 with a small flat wrench and then sliding the member 22 either back or forward as the case may be, after which the screw 23 is tightened to hold the member 22 in its set position.

The adjusting member 22 has the still further function of holding the pivot pin 25 in position, keeping the same from sliding lon-' gitudinally and also preventing the pin 25 from rotating. These results are accomplished by providing the pin 25 with a notch into which the member 22 fits snugly, as can be seen in the drawing. This pin is notched on one side only, and is not provided with a groove extending all the way around the pin for the reason that it is desired that the pin always remain in one position so that in case it is not mechanically perfect or is slightly bent, the adjustment of the armature is retained, which would not be the case if the pin were permitted to rotate.

It is well understood that the pin 25 could be secured so that it would not move longitudinally or rotate by anyone of a number of means, such as flattening the ends. If the pin were secured in thisway, however, it could not be readily removed in order to permit the removal of the armature 19 or the magnet 10, which may become desirable in 'case either is found to be defective or unsatisfactory. It will be seen, however, that the arrangement shown in the drawingis such that the pin 25 may be easily removed by merely raising the adjusting member 22 out of engagement therewith vand drawingthe pin 25 outfrom either side.

The bearing surface of the armature 19 is increased by the bushings 27 and 28, as can best be seen in Fig. 3. This broader bearing surface gives the switch a longer life by distributing the wear over a greater area.

Another feature of improvement contained of a pawl operated by the armature for driv-' ing the ratchet, said pawl constructed of sheet metal folded to give a U shaped cross section,

two ears at one end of said pawl disposed on opposite sides of said armature, a pivot passing through said ears and the armature, and a spring having one end attached to the end of thearmature at a point beyond the pivot and the other end'attached to the pawl at a point between the pivot and the driving end of the pawl, the parts being so arranged that the spring holds the driving end of the pawl against the ratchet wheel and at the same time pulls the pawl against the pivot substantially in line with the direction in which drivingforce is applied to the ratchet, thereby preventing play in the pivot during operation.

2. A spring adjusting device for switches mounted close together, comprising a bracket adjustably attached to the frame of aswitch between such switch and the one next to it, an arm on said bracket to which the motor magnet spring is attached, and a second arm for said bracket extending out between the switches where it can be easily reached when it' is desired to adjust the bracket to regu-' late the spring tension.

3. The combination, with a switch magnet armature, of a pivot rod for said armature notched at one end, and an armature spring adjusting bracket attached to the switch frame, said bracket having an arm lying in the notch in said rod, whereby the rodholds the bracket in position and the arm prevents the rod from turning and from moving endwise. 1

4. The combination, with a switch magnet armature, of a pivot rod for said armature notched at one end, and an armature spring adjusting bracket attached to the switch frame at a single point, said bracket having an arm lying in the notch in said rod, where-. b the rod prevents the bracket from turning a 'out its supporting means and the arm retains said rod in position.

, In combination, a switch frame comrising a vertical member, a horizontal memr extendin at right angles to said vertical member, and two other horizontal members parallelto said first horizontal member, a magnet core secured at one end to said first horizontal member and having the other end disposed between said other horizontal members, a pivot rod extending through the said other horizontal members, an armature for said magnet core pivoted on said rod at two points inside said other horizontal members, contact springs operated by said armature, and a spring mounting bracket having one end secured to said first horizontal member and having the other end bearing against said pivot rod between the ints at which the armature is pivoted, sai bracket servin to brace the frame and stifi'en the pivot ro 6. The combination, with a switch driving magnet secured to the switch frame and an armature pivoted on a rod extending through extensions of said frame, of a sprin mountspring adjustin bracket slidabl mounted on the switch ame and secure at a single point, said bracket havin an arm lying in the notch in said rod, where y the rod prevents the bracket from turning about said systems having rotatable wipers in which the pawl for operating the ratchet wheel is constructed from a single piece of sheet metal bent in the shape of a U with one edge of the base of the U suitabl shaped to engage with the teeth of the rate et wheel.

10. In an automatic switch for telephone systems, a set of bank contacts, a set of wipers havinga'ccess to said contacts, a motor magnet having an armature adapted, to operate a pawl and ratchet wheel to rotate said wipers over said bank contacts, said pawl comprising a single U-shaped sheet of metal having extensions of the two legs pivoted to the endof said armature and one edge of the base of the U flattened out to engage with the teeth of said ratchet wheel.

In witness whereof -I hereunto subscribe my name this 10th day of March, A. D. 1923.

JOHN ERICKSON.

ing bracket acting as a brace for t e frame and said extension iwhen the magnet is en-' ergized and acting also as a support for said rod between said extensions.

-. 7. In an-automatic switch, the combination, with a ratchet wheel and an armature, of a pawl operated by the armature for driving the ratchet, a pivot rod for rotatably mounting said pawl on said armature and a spring having one endattached to the end of the armature at apoint beyond the pivot and the other end attached to'the pawl at a point between the pivot and the dnvin end ofl-the pawl, the parts being so arran that the sp holds the end of t e pawl agains t tie ratchet wheel continually and at the same time pulls the pawl against the pivot substantiall in line with .the direction inwhich driving One is applied to the ratch- 4 et, thereby preventing play in the pivot-during 0 ration. 8. e combination, with a .switch magnet armature, of apivotrod for said armature notched near one end, and an armature

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