US2159503A - Switching mechanism - Google Patents

Description

May 23, 1939. F. s- DENISON n AL SWITCHING MECHANISM Filed Jan. 2, 1937 Inventors Fweefck Denison T/I/'Zlz'czm E Harrison Ernest M JJL'ZZe /wM A? farne@ Patented May 23, 1939 PATENT GFFICE SWITCHING MECHANISM Frederick S. Denison, William Ernest M. Miller, Minneapolis, Minn.,

E. Harrison, and assignors to Minneapolis-Honeywell Regulator Company.'

Minneapolis, Minn., ware a corporation of Dela- Application January 2, 1937, Serial No. 118,782

22 Claims.

This invention relates to switching mechanism and more particularly to that type of control wherein a switching mechanismactuated by a condition responsive element serves to open or 6 close a circuit or a plurality of circuits.

While this invention has particular utility in the control of an oil burner having an ignition mechanism in association therewith and. will be hereinafter described in such connection, it is also adapted to be used with other heat producing devices in the generalart of heat control.

One object of this invention is the provision of an improved connection between a condition responsive element or member actuated thereby l. and circuit controlling mechanism whereby, upon motion oi the condition responsive element within predetermined limits, the circuit controlling mechanism will be actuated, but upon motion in excess of such limits, the element may continue 2o to move without imparting further movement to the circuit controlling mechanism.

A further object resides in the provision oi a mechanism adapted to function as set forth in the preceding paragraph in conjunction with a longitudinally movable bar or rack actuated by a thermostatlc element.

A further object is the provision of improved means actuated by a thermostatic element through a linearly movable rack and the connection as above set forth to actuate a plurality of contacts, one or more of which moves to open position and the others of which move to closed position on condition change in one direction, the motion being reversed upon condition change in the opposite direction, so arranged that the closing of certain of the contacts occurs before opening of others upon condition change in one direction and the others close subsequent to the opening of the first mentioned contacts upon motion in the opposite direction.

An additional object is theprovision in such a mechanism as above mentioned oi an improved means to impart a relatively rapid or snap action to the movement of one or more of the contacts. I

A further object is the provision ot means associated with the last mentioned means to provide a lost motion connection between the contact or contacts moved with a snap action and the member actuating the same.

lAzstill further object is the provision of an improved connection between a linearly movable member actuated by a thermostatic element .and contact structure actuated thereby, the member the mechanism for actucomprising a rack and (Ul. 20D-138) ating the switch including toothed members cooperating with the rack.

A further object is the provision of an improved slip friction mechanism in association with the toothed members cooperating with the above mentioned rack.

An additional object is the provision ofl an improved switching mechanism of the same general type disclosed in the co-pending application of Ernest M. Miller, Serial No. '77,758 led May 4, 1936, entitled Control mechanism and assigned to the same assignee.

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

The invention accordingly consists in the features of construction, combinations of elements and arrangements of parts, all as will be more fully described hereinafter and disclosed in the accompanying drawing.

In the accompanying drawing, wherein is shown illustratively one of the various possible embodiments of this invention:

Figure 1 is a side elevational view of a control mechanism embodying the structure of the instant invention.

Figure 2 is an enlarged iront elevational detail view of certain features of construction embodied in the instant invention.

Figure 3 is a side elevational view` taken along the line 3 3 of Figure 2 as viewed from the right.

Figure 4 is a side sectional view taken along the line 4-4 oi Figure 2 as viewed from the right,

and l Figure 5 is a side sectional view taken along the line 5-5 oi Figure 3 as viewed from the left.

Similar reference characters denote similar parts throughout the several views of the drawing.

Referring now to Figure 1, there is generally indicated at I II a base member to which is secured in any suitable manner a peripheral flange II l which in turn has secured thereto an insulating panel I2 having an aperture I3 therethrough. A sleeve I4 extends outwardly through a suitable aperture I5 in member III and is secured in aperture I5 by an inwardly turned flange I6, the parts being held in related assembly in any suitable manner, as by soldering. Sleeve I4 has rigidly secured adjacent the outer end thereof a supporting member I1 which has an aperture I8 in the outer end thereof. A thermostatic element generally indicated'at 20 which may be comprised of two substantially U-shaped sections 2i and 22,

one of which has an inwardly extending projection 23 adapted to be passed through aperture I8 and thus held in position adjacent member I1, abuts and is secured to a rim 24. Rim 24 is in turn rigidly ailixed to a linearly movable rod 25 which extends inwardly through an aperture 26 in member I1 and sleeve I4 through a. shield 21 positioned in sleeve I4 and is secured to an insulating block 28 in any suitable manner. A spring 29 positioned between a flange 30 on insulating block 28 and shield 21 serves to force block 28 and hence rod 25 inwardly in a direction away from bimetallic element 20. Secured to the other end of insulating block 28 as by threaded engagement therewith and held in place. as by a nut 35 is a member 36 the inner extremity of which terminates in a rack 31 provided with a plurality of teeth. Rack 31 passes inwardly through aperture I3 and is associated in a manner to be hereinafter described with the switching mechanism generally indicated at 40 (see Figure l). It may here be pointed out that a suitable housing 4I is provided in order that the parts of the said switching mechanism may be protected from injury as well as to enhance the appearance of the mechanism.

Referring now to the switching mechanism generally indicated at 40, a bracket 50 is rigidly secured as by screws 5| to insulating panel I2. Bracket 50 has an aperture 52 (see Figure 4) positioned for registry with aperture I3. Passed transversely through suitable registering apertures in the opposite walls of bracket 50 are a pair of axle- like members 54 and 55. Axle-like member 54 has mounted thereon a channel-shaped member 51 which includes a pair of substantially arcuate portions 58 having suitable apertures therein through which axle.54 passes. A resilient spring member 59 is secured as by rivets 50 to the inner portion of channel-like member 51. Resilient member 59 carries at 'its outer extremity a contact 6| adapted to pass through an aperture 62 (see Figure 4) in channel-shaped mem.

ber 51, contact 6| being positioned for engagement with an opposed contact 164 carried by a bracket 65 secured to insulating panel I2 as by a terminal screw 66. A suitable stop member 61 including an angularly disposed portion 68 is positioned adjacent channel-shaped member 51 and serves as a stop to limit the motion thereof in a manner to be described hereinafter. Positioned inside of rounded portions 58 of channel-shaped lmember 51 are a pair of friction discs 10 held in place by a pair of opposed washers 1|, which washers in turn are rigidly secured to a pair of identical gears 12 the teeth of which are of a configuration to register with the teeth on rack 31. A helical spring 18 surrounding axle 54 fitsv into opposed recesses 19 in gears 12 and serves to urge the same and their associated collars into frictional engagement with friction discs 10.

Thus from the foregoing it will be seen that condition change in the region' adjacent bimetallic element 20 is transmitted to linear movement of rod 25 and hence rack 31 and acting through gears 12 and friction discs 10, serves to move channel-shaped member 51 and its associated contact 6| towards or away from opposed contact 64, resilient member 59 serving as a strain release and likewise to provide a relatively non-vibrating contact and friction discs 10 serving as a slip friction means whereby excessive movement of rack 31 occasioned by excessive condition change is not transmitted to movable contact 6| through channel-shaped member 51.

Axle 55 correspondingly carries a channelshaped member having rounded portions 8| positioned inside the walls of bracket 50. Friction discs 82 are also provided as are collar members 83 secured to gears 84 similar to-gears 12. A spring 85 similar to spring 18 biases gears 82 and their associated collars 83 into engagement with friction discs 82 in the same manner pre-l viously described in connection with gear 12 and friction discs 10. yA cam member is rotatably positioned on a sleeve 9| surrounding spring 85 on axle 55 between gears 84. Sleeve 9| precludes the engagement of cam member 90 with spring 85, permitting free rotation of the former. Channel-shaped member 80 carries a threaded collar 94 adjacent its extremity, which collar carries a screw 95. An extending portion 96 carried by bracket 50 has an angularly disposed portion 91 provided with a threaded aperture in which is positioned a screw 98 held in place by a lock nut 99. Screw 98 serves as a stop means for motion in one direction of channel-shaped member 80. Screw is adapted to abut a second stop member |00 comprising an inwardly extending portion |0| extending into the pathof movement of screw 95 when moved by channel-shaped member 80. A screw |02 secures bracket |00 to isulating panel I2.

Thus it will be seen that movement is imparted to channel-shaped member 80 by movement of rack 31 through gears 84 and friction discs 82 in a manner similar to that discussed in connection with channel-shaped member 51.

Referring now to cam-like member 90, as better shown in Figure 4, member 90 is bifurcated at an extremity and consists of two portions |05 and |06 spaced apart a distance greater than the thickness of the upper wall of channel-shaped member 80, it here being pointed out that the upper wall of channel-shaped member 80 extends only a portion of its length as shown in Figures 3 and 4, whereby to provide a surface for alter- 1 nate engagement with members |05 and |06 of member 90. Extending in a direction towards insulating panel I2 from that portion of member 90 surrounding axle 55 is a cam surface |01. Cam surface |01 is provided with a relatively sharp shoulder |08 positioned adjacent which is a roller` |09 carried by a bracket ||0 comprising a portion of a member III, which is in turn secured to a resilient leaf I2 as by rivets I3, leaf I2 being secured as by rivets ||4 to a bracket ||1 carried by insulating panel I2 which may comprise, if desired, an integral portion of bracket 50. Member I I carries a contact I I8 and resilient member I2 carries a second contact ||9 which projects through an aperture in member III. A bracket |20 secured in any desired manner to a suitable terminal carried by panel 2 in turn supports a contact |2I positioned for engagement with contact II8. A second bracket |22 carries a contact |23 positioned for engagement with contact II9.

Thus from the foregoing it will now appear that motion is imparted to channel-shaped member 80 by gears 84 in the manner previously described and that such motion is imparted through the lost motion connection comprised of members |05 and |06 to cam member 90, screws 95 and 98 limiting, as previously mentioned, the movement of channel-shaped member 80.l The movement of cam member 90 is in turn transmitted through cam surface |01 to roller |09 and hence through members III and |||2 to contacts I|8 and |I9. Thus when roller H09 passes shoulder |08 of cam surface |01 contacts |18 and ||9 move into engagement with LLI their opposed contacts |2| and I 23 with a relatively rapid snap action. Consequently, upon reverse movement of rack 31 occasioned by a change in condition in the opposite direction roller |09 rides up shoulder |00 and the above mentioned con-tacts are separated. It should here be noted, however, that due to the lost motion connection previously described contacts ||9 and ||8 engage and/or disengage their opposed contacts |2'| and |23 subsequent to the engagement and/or disengagement of contacts 6| and 64 since motion of rack 31 is immediately and directly transmitted to motion of Contact 6| whereas the lost motion connectionpreviously referred to retards the immediate transmittal of such motion to contacts ||8 and ||9. The utility of this arrangement will be readily appreciated by those skilled in the art and the structure embodying such a "contact arrangement may be advantageously utilized with the system disclosed in the previously mentioned Miller application.

It will also be' noted that axle 55 is longer than corresponding axle 54 and carries, as best shown in Figures 2 and 3, on that portion thereof which extends beyond the wall 4of bracket 50 a cam 30. Cam |30 is provided with an aperture I3| adapted for engagement with a projection |32 carried by channel-shaped member 00, .aperture I3|, being of greater extent than the dimensions of projection |32 whereby to provide a lost motion connection between projection |32 and aperture I3|. Cam |30 is provided with a cam surface |35 having a relatively sharp shoulder |36 (see Figure 3). Positioned adjacent cam surface |35 for engagement therewith is a roller |40 carried by a bracket I4| which is in turn carried by a member |42 secured as by a rivet |43 to a resilient member |44. Resilient member |44 is in turn secured to a terminal |45 in electrical contact as by a bridge |46 with a terminal screw |41. Terminal |45 also carries a relatively rigid member |48 which serves as a stop to limit the upward movement of resilient member |45 which is biased by its own resiliency in a direction toward cam surface |35. Resilient member |44 carries at its end a contact |50 positioned for engagement with an opposed stationary contact |5| carriedby a bridge |52 in electrical engagement with a suitable terminal |55. Thus from the foregoing it will also be seen that movement of channel-shaped member through the gear and rack arrangement previously described results in the opening and/or closing of contacts |50 and |5| with a relatively rapid or snap action occasioned by the passage of shoulder |36 over roller |40, the lost motion connection provided by aperture I3| and |32 servingto retard such opening or closing until subsequent to the corresponding opening or closing of contacts 6| and 64. It will also be readily understood that by suitable positioning ofcam |30 and/or cam member 90 the relative timing of the opening and/or closing of contacts |50 and |5| with respect to contacts ||8 and ||9 and their `opposed contacts |2| and |23 may be suitably varied to provide a desired sequence of operation in accordance with the particular installation.

The control mechanism hereinbefore described may be readily utilized for any desired purpose, but as previously mentioned its utility in conjunction with an oil burner assembly and particularly an assembly including such ,a circuit as described in the previously mentioned application of Ernast M. Miller, will .be readily ap? preciated.

From the foregoing it will now be seen that there is herein provided a structure which accomplishes the objects of this invention and others including many advantages of great practical utility.

As many possible embodiments may be made in the above structure and as many modifications may be made in the embodiment above described, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

We claim as our invention:

1. In a switching mechanism in combination, a condi-tion responsive element, a rod movable thereby, teeth on said rod, a rotatable toothed member, the teeth on said rod and said member coacting, an arm movable by said toothed memu ber, stops for said arm, a connection between said arm and said toothed member permitting continued movement of said toothed member after said arm has been stopped, a first contact carried by said arm, and a second contact positioned for engagement with said rst contact.

2. In a switching mechanism in combination, a condition responsive element, a rod movable thereby, teeth on said rod, a rotatable toothed member, the teeth on said rod and said member coacting, means movable by said toothed member, a yieldable connection between said means and said toothed member to provide a friction drive from said member to said means but adapted to slip upon excess rotation of said rotatable member, a first contact carried by said means, and a second contact positioned for engagement with said first contact.

3. In a switching mechanism in combination, a condition responsive element, a rod movable thereby, teeth on said rod, a rotatable toothed member, the teeth on said rod and said member coacting, an arm movable by said toothed member, a yieldable connection between said arm and said toothed member, said connection comprising a friction disc interposed between said arm and said member to provide a friction drive from said member to said arm but adapted to slip upon excess rotation of said rotatable member, means resiliently urging said arm and said member into frictional engagement with said disc, a rst contact carried by said arm, and a second contact positioned for engagement with said first contact.

4. In a switching mechanism in combination, a condition responsive element, a rack movable thereby in accordance with changes in the value of the condition to which said element responds, an axle adjacent said rack, a pair of gears carried by said axle in mesh with said rack, a channel shaped arm mounted on said axle, the side walls thereof being positioned adjacent remote sides of said gears, friction discs between said gears and said side walls, a spring surrounding said axle between said gears and biasing the same in the direction of said friction discs whereby movement of said gears by said rack is imparted to said arm, a rst contact carried by said arm, and a second contact positioned for engagement with said first contact.

5. In a switching mechanism in combination, a condition responsive element, a rack movable thereby in accordance with changes in the value of the condition to which said element responds, an axle adjacent said rack, a pair of gears carried by said axle in mesh with said rack, a channel-shaped arm mounted on said axle, the side walls thereof being positioned adjacent remote sides of said gears, friction discs between said gears and said side walls, a spring surrounding said axle between said gears and biasing the same in the direction of said friction discs whereby movement of said gears by said rack is imparted to said arm, a cam movable by said arm, a movable contact adjacent said cam and movable with a snap action thereby, and a fixed contact positioned for engagement with said movable contact.

6. In a switching mechanism in combination,

y a condition responsive element, a rack movable thereby in accordance with changes in the value of the condition to which said element responds, an axle adjacent said rack, a pair of gears carried by said axle in mesh with said rack, a channelshaped arm mounted on said axle, the side walls thereof being positioned adjacent remote sides of said gears, friction discs between said gears and said side walls, a spring surrounding said axle between said gears and biasing the same in the direction of said friction discs whereby movement of said gears by said rack is imparted to said arm, a cam movable by said arm, a lost motion connection between said cam and said arm, a movable contact adjacent said cam and movable with a snap action thereby, and a xed contact positioned for engagement with said movable contact.

7. In a device of the character described, in combination, a condition responsive element, a rack movable thereby, a pair of axles oppositely disposed with vrespect to said rack, gears carried by each of said axles cooperating with said rack and rotatable thereby, arms movable by each 'of said gears, and condition control means movable by each of said arms.

8. In a device oi the character described, in combination, a condition responsive element, a rack movable thereby, a pair of axles oppositely disposed withrespect to said rack, gears carried by each of said axles cooperating with-said rack and rotatable thereby, arms movable by each of said gears, condition control means movable by one of said arms, a cam carried by one of said axles and movable by one of said arms, and additional condition control means operable by said cam.

9. In a device of the character described, in combination, a condition responsive element, a rack movable thereby, a pair of axles oppositely disposed with respect to said rack, gears carried by each of said axles cooperating with said rack and rotatable thereby, arms movable by each of said gears, condition control means movable by oneof said arms, a cam carried by the other of said arms and movable thereby, and additional condition control means movable by said cam.

10. In a device of the character described, in combination, a condition responsive element, a rack movable thereby, a pair of axles oppositely disposed with respect to said rack, a gear carried by each of said axles cooperating with said rack and rotatable thereby, arms movable by each of said gears, condition control'means movable by one of said arms, a cam carried by the other of said arms and movable thereby, additional condition control means movable by said cam, and a lost motion connection between said cam and its associated arm whereby said iirst condition control means is operated by movement or" said rack prior to operation of said second condition control means.

11. In a switching mechanism in combination, a condition responsive element, a rack movable thereby, a supporting member, an axle carried by said supporting member adjacent said rack, a pair of gears carried by said axle and meshing with said rack, a. channel-shaped member mounted on said axle, said gears being positioned between the side walls of said member, a recess in each of said gears, a helical spring on said axle, an end thereof seated in each of said recesses biasing said gears towards said side walls, friction discs between each of said gears and its associated side wall, whereby a slip friction driving connection is provided between said gears and said arm, and control mechanism operable by said arm.

12. In a switching mechanism in combination, a condition responsive element, a rack movable thereby, a supporting member, an axle carried by said supporting member adjacent said rack, a pair of gears carried by said axle and meshing with said rack, a channel-shaped member mounted on said axle, said gears being positioned between the side walls of said member, a recess in each of said gears, a helical spring on said axle, an end thereof seated in each of said recesses biasing said gears towards said side walls, friction discs between each of said gears and its associated side wall, whereby a slip friction driving connection is provided between said gears and said arm, a sleeve positioned about said spring between said gears, a cam pivoted on said sleeve, said cam being movable by said arm, a Contact movable by said cam, and a xed contact positioned for engagement with said movable contact.

13. In a switching mechanism in combination, a condition responsive element, a rack movable thereby, a supporting member, an axle carried by said supporting member adjacent said rack, a pair of gears carried by said axle and meshing with said rack, a channel-shaped member mounted on said axle, said gears being positioned between the side walls of said member, a recess in each of said gears, a helical spring on said axle, an end thereof seated in each of said recesses biasing said gears towards said side walls, friction discs between each of said gears and its associated side wall, whereby a slip friction driving connection is provided between said gears and said arm, a sleeve positioned about said spring between said gears, a cam pivoted on said sleeve, a lost motion connection between said channelshaped member and said cam whereby movement of said rack is retarded in transmission to said cam, and control mechanism operated by said cam.

14. In a switching mechanism in combination, a condition responsive element, a rack movable thereby, a supporting member, an axle carried by said supporting member adjacent said rack, a pair of gears carriedby said axle and meshing with said rack, a channel-shaped member mounted on said axle, said gears being positioned between the side walls of said member, a recess in each of said gears, a helical spring on said axle, an end thereof seated in each of said recesses biasing said gears towards said side walls, frictiondiscs between each of said gears and its associated side wall, whereby a slip friction driving connection is provided between said gears and said arm, a sleeve positioned about said spring between said gears, a cam pivoted on said sleeve,

a second axle carried by said support, a second pair of gears rotatably mounted thereon, a second channel-shaped member carried by said second axle, a second spring biasing said second gear towards the side walls of said second channel- 'shaped member, friction discs between said second gears and said second side walls, control mechanism directly movable 'f by said second channel-shaped member, a lost motion connection between said cam and said first channelshaped member, and additional control mechanism operated by said cam whereby movement of said rack is transmitted to said cam and said additional control mechanism subsequent to transmission to said first mentioned control mechanism.

15. In a switching mechanism in combination, a. condition responsive device, a rod movable thereby, teeth on said rod, a pluralityfof rotatable toothed members cooperating with said rod, a control member operated by each of said rotatable members, and slip friction means connecting each rotatable member with its control member.

16. In aswitching mechanism in combination, a condition responsive device, a rod movable thereby, teeth on said rod, a plurality of rotatable toothed members cooperating with said rod, a control member operated by each of said rotatable members, slip friction means connecting each rotatable member with its control member, and switches operated by each of said control members, said switches being operative at different times.

17. In a switching mechanism in combination, a condition responsive device, a rod movable thereby, teeth on said rod, two rotatable toothed members cooperating with said rod for rotation thereby, a pivoted arm, a switch operated thereby, slip friction driving means connecting said arm to one oi' said rotatable members, stops for limiting the rotation of said arm by said rotatable member to a relatively narrow range, a second pivoted arm, a switch operated thereby, slip friction driving means connecting said second arm to the other rotatable member for rotation thereby, and stops for limiting the rotation of said second`arm to a substantially wider range Lvllereby said switches are operated at dinerent 18. In a switching mechanism in combination'I a condition responsive device, a rod movable thereby, teeth on said rod, two rotatable toothed members cooperating with said rod for rotation thereby, a pivoted arm, a switch operated thereby, slip friction driving means connecting said arm to one of said rotatable members, stops for limit-- ing the rotation of 'said arm by said rotatable member to a relatively narrow range, a second pivoted arm, a pair oi switches operated thereby, slip friction driving means connecting said second arm to the other rotatable member for rotation thereby. a cam operated by said second arm. another switch operated thereby, stops for limiting the rotation of said second arm to a relatively wider range, and means for adjusting said stops whereby the time of operation of the switches by the second armis varied with respect to the operation of the switch by the nrst arm.

19. In'a switching mechanism in combination.

a. lever, a rotatably mounted cam, a stationary contact,aswitchanncarryingamovablecontact, meansbiasingoneendofseidswitchanninto engagement with said cam. said cam having ls.

high portion which in certain positions of said cam holds said contacts separated against the force exerted by said biasing means, a low portion which permits said biasing means to close said switch contacts, and a steep slope between said two portions, a lost lmotion'connection between said lever and cam so that as said cam is rotated in one direction by said lever said switch arm will pass from the high portion to the low portion of said cam with a snap action, a condition responsive element, an operating member connected thereto, and slip friction driving means between said member and lever.

20. In a switch mechanism in combination, a condition responsive element, an operating member connected thereto, a switch arm, slip friction means connecting said switch arm to said operating member, stops for limiting movement of said switch arm, a second switch, a third switch, and means connected to said operating mechanism for operating said second and third switches with a snap action.

21. In a switch mechanism in combination, a condition responsive element, an operating member connected thereto, a switch arm, slip friction means' connecting said switch arm to said operating member, stops for limiting said switch arm to a relatively small movement, a first switch actuated by said switch arm, an actuating member, slip friction means connecting said actuating f member to said operating member, stops for limiting said actuating member to a greater movement than said switch arm, a second switch, a third switch, movement of said condition responsive element in one direction causing said switch. arm to close said'rst'switch, first means actuated by said actuating member for opening said second switch after said first switch has been closed, and second means actuated by said actuating member for snapping said third switch to open position, movement of said condition. responsive element in the opposite direction first causing said switch arm to open said first switch, then causing said actuating member to actuate said first means to snap said second switch closed, and saidv second means to close said third switch.

22. In a switch mechanism in combination, a condition responsive element, an operating member connected thereto, a switch arm, slip friction means connecting said switch armto said operating member, stops for limiting said switch arm to a relatively small movement, a first switch actuated bysaid switch arm, an actuating member, slip friction means connecting said actuating member to saidoperating member, stops for limiting said actuating member to a larger movement than said switch arm, a second switch, a third switch, first and second cams connected to said actuating member, movement of said condition responsive element in one direction causing said switcharmtoclosesaidrstswitchandlater causing said actuating member to rotate said iirst and second cams to open said second and third switches, movement of said condition responsive element in the opposite direction causing said switch arm to open said nrst switch and later causing said actuating member to rotate said first and second camsto close said second and third switches.

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