US2579406A

US2579406A - Front edge detector mechanism for use in sheet feeding apparatus

Info

Publication number: US2579406A
Application number: US764314A
Authority: US
Inventors: Tebbs George William
Original assignee: Headley Townsend Backhouse
Current assignee: Headley Townsend Backhouse
Priority date: 1946-03-21
Filing date: 1947-07-29
Publication date: 1951-12-18
Anticipated expiration: 1968-12-18

Description

-an event occur.

sensing that the feeler about its pivot' by .the lays in proper sequence causes Patented Dec. 18, 1951 v FRONT EDGDETECTOR'MECH'NISM FOR USE IN- assignor 'to Headley Wentwo'th, Surrey, England Application July 29, 1947, Serial No. -764-,314 In Great Britain March 21, 1946 Section 1 Public Law 696, August 8, 1946 Patent This invention comprises improvements' in or relating to front edge detector mechanism for use in sheet feeding apparatus. The invention isconcerned with sheet eeding apparatus of the kind (hereinafter referred to as the kind'described) in which sheets of paper or the like are removed in succession from a pile and ied'on to a layboard where, by means of lays or theequivalent, registration of the sheets is effected before' they are transferred to a printing or other machine. In one form of such apparatus With which 'the invention is particularly, but not exclus'ively, concerned the sheets approach the lay-'board 'in a continuous stream of partly overlapping sheets.

Sheet feeding apparatus of this form are commonly known as stream-feeders.

. It is an object of the invention to provide in sheet feeding apparatus of the kind described new or improved mechanism for detecting' the non-arrival or delayed arrival of a sheet at the lays and for stopping the feeding of'the sheets and/or Operating a Warning device should* such With the above object in vieW- the invention provides, in or for sheet feeding 'apparatus' of the kind described front' edge detector mechanism comprising a feeler movably supported in the path of the sheets at or near the'ffo'nt'lays and arranged for movement by'each sheet' in turn as the sheet approaches' orreaches the front lays and` sensing mechanism 'o'prated in timed relationship' withth`e sheet- -ie'edin'g mechanism for determining whether o'r'n'ot the feeler has been moved as a-foresaid by 'a correctly placed sheet. In the preferredoform of'theinvention the sensing mechanism is arranged-oh has' not been moved ior causing stoppage 'of the feeding of the sheets and/or the operation of a warning device'. I In a convenient form of the invention the feele'r comprises a pivoted arm arrangedxto be'fnoved or reach the front lays. The sensingmechanism may comprise an arm 'or the' equivalent constantly oscillated in timedrelationship with the feeding of the sheets in combination with trip mechanism having a stoppresentedfor engage- ;mentby the sensing arm during each forward 'movement thereof and on such enga-gementto restrict further movement of the arm butrarranged to be withdrawn from said path on* each movement of the feeler as aforesaid the operation of the sensing mechanism being so timed that each sheet as it 'arrives at or approaches .the stop to be the sheets as they approach' SHEET FEEDINGF APPARATUS George William Tebbs, Wc

odiordGreen, England, 'Iownsend Backhouse,

expires March 21, 1966 y 8 Claims. (01. .2`71- -5j6, v v

'withdrawn before engagement with the sensing 'arm' but should a sheet be delayed or fail to *feed the 'stop Will engage the arm and cause the stoppage of the feeder or .the operation of the warningSdevice. v r'In the preferred construction of the invention the trip mechanism comprises a lever which is s'pring-urged from a stop position in which one end 'of the lever, constituting the stop; lies in the path of the sensing arm as aforesaid and the other 'arm has a 'latching engagement with the feeler such that the lever is prevented from moving out of the 'stop position until the feeler is'moved by a sheet whereby unless such movement of the feeler occurs at the appropriate time the 'lever engage's and stops the sensing arm. -The trip mechanism may include a re-setting device operable to re-set the lever into the stop position'between the feeding of each sheet *and comprising a bell crank of which one arm is :ar'ranged for engagement by the sensing arm near the end of the backward stroke thereof and .the beli crank is thereby given a movement of rotation about its pivot and the other arm is arranged, on such rotation, to re-set the lever into the stop position. Preferably the re-setting device 'isi arranged to hold the lever in the stop position and out of contact with the feeler during'the' period when the feeler is engaged and moved by a properly fed sheet whereby the resistance to movement of the feeler by the sheet is reducd.

i One' specific form of the mechanism according 'to the invention will now be described by way of' example 'and with reference to the accompanying drawing which represents a side View of the mechanism. In this example the mechanism is' intended for use in a stream feeder which feeds the sheets in overlapped formation on to a lay-'board l having front lays in the form of arms' 2 pivoted on a cross shaft 3 below the board and, 'during the registration period, extending above the board to provide registration stops. The mechanism comprises a bracket 4 adjustable along a fixed cross shaft 5 mounted above the lay-board and behind the front iays. The bracket -has a rearward extension 6 constituting aoear.- ing for an oscillating shaft 1. Extending in the =forward direction from the underside of the bracket substantially parallel to the lay-board there is an arm 8 of inverted channel section. The arm reaches to the front edge of the layboard-. A bolt 9 and knurled nut o are employed to secure the arm to the bracket and in order thata limited degree of lengthwise adjustment of the arm may be made an elongated slot ll for the bolt 9 is formed on the arm. Near the front end of the arm at a position just behind the front lays there is a pivoted 'lever I"2 'depen-dent from the arm and constituting the ijeeler. This feeler is urged into the vertical position by a spring !3. At its lower end the feeler is forked and embraces one end !4 'of -a lever pivotally supported at I 6 within the channel section oi' 'the arm 8 and extending lengthwise of the arm. When in its normal, vertical position the lower end of the feeler extends into a slot 11 cut in the lay-board. When the feeler is engaged 'by a sheet being moved in the feeding direction it is swung about its pivot into the position shown in chain lines and the sheet slides under the end of the feeler. The lever !5 has a step 18 'at the end embraced by the forked feeler and is ar ranged to limit the rearward movement of the feeler. Further the stepped end |4 constitutes a latch engaging the feeler 'and so arranged that when the feeler is in the vertical position rotation of the lever 'about its pivot support in the clockwise "direction 'as viewed in the figure is prevented but is permitted when the feeler has been tmoved by a sheet into the 'chain line position.

Dependent from 'the oscillating shaft 'I there is .an arm ia-the sensing armwhich `oseillates :above the'En-d of the lever 45 remote ;from the .feeler. This :arm is arranged near the end of its backward 'stroke to engage one arm 20 of a !bell -cr ank lever of which the other arm 21 engages underneath .the end of the `lever !5. An adjusting screw '22 'on the bell crank lever is 'used to detetmine the exact position at which it is .engaged by the eensing arm. The bell crarrk is pivoted tor-mechanism described above is adjustable in position in a direction across the width of the lay-board and that for this purpose the bracket .4 is split at 26 and provided witha clamping screw 21 'whereby it may be clamped on the shaft 5 and the sensing arm is also split and provided with a screw 28 for clamping on the shaft 1.

1.' Front edge detector mechanism for sheet feeding apparatus of the kind described and embedying a laivboard and front lays up to which the front edge of each sheet in turn is moved for registration, said mechanism comprising a feeler in :the form of apivoted arm arranged to be partial ly rotated about its pivot by engagement with the front edge of each sheet in turn 'as it approache's the front lays, a sensing member proi viding a. sensing abutment arranged to be constantly oscillated in .timed relationship with the within the arm 8 and a 'suitable stop '2'3 limits the v Iotation of 'the crankin tion.

The mechanism functions in the following manner. When a sheet is approaching the feeler 12 the lever 5.5 lis in l atching engagement with the feeler at its front end and ;its rear end is elevated into the path of the 'osci-llating :sensing am N. Should a sheet the correct time the travel will engage the anticiockwise directhe end of the lever and its movement will be stopped which by suitable well,

known means not shown, the sheets to be stopped. the feeding is p'oceeding causes the feeding of normally and e. sheet -arrives at the feeler in the correct timed relationship the 'feeler will ce moved-into the chain line position-which releases the latching engagement of the lever and pe'mi ts a spring 24 tomowe the lever :out of the path of the forward stroke ef the;

sensi-ng arm. During the backward ;Stroka the .sensingarn en-gages the arm 'ZO -of the bell Grafik( and rotates the -bell -crank to cause the arm Zi thereof to return the lever 1:5 .in-to 'the position in which its front end 'is in latchirrg :engagement with the feeler and it's rear end lies in the path e: the sensing .ar-m.

In order to redce ?the resistance to *movement oiiiered'by the feeler to the paper the 'sensirrg amm .i arfanged to 'maintain the 'bell crank in engagef- .men-t with the lever and there'by to maintain the :front end of the lever out of actual 'contact with the feeler during the period 'within which a 'cor rectly placed `sheet will engage the feel'er.

.it is 'to be understood that 'more "than one ee'ler :and asscc-iated sensing adevice may be 'provided and spaced :apart across the width of the ia-yhoard. It is :also to be understood 'that the detec- If on the other hand' fail to arrive at the feeler .at .e 'osc'llatin'g .arm .in its forward eeding of the sheets, a stop member intermediate between the eeler and the sens-ing abutment and having a releasa bl-e latching engagement with the feeler ?by which the 'stop member held in e. position in which it lies in the path of the causing abutment and is operative to engage the :abutment and stop the movement -'Of the sensing member the latching engagement being `releas- &bi'e -on movement of the eeler as aforesaid by correctly timed sheet, means for constantly nrging the stop mem-ber :against the latch control of the feeier to a position outside the path of the causing abutment in 'which the stop member is inoperative to stop the 'sen-sing 'member and secondary means eomprisng -a member movable ;in timed relationship with the f eeding of the ;sheets to engage and temporarily to support the :stop member against the :said urgng means during *the time when :the feeler to be engaged by a correctly presented :sheet :thereby to relieve the feeler of :frictional engagement with the stop member during that time and to allow the feel-er to' be freely moved by suo a sheet to a position in which the feeler releases the latching eneagement of the stop member .and the stop mem- :ber is permitted to .move :to the inoperativeipositim -on removal of the temporary support.

2. Front edge detector mechanism as 'claimed :in claim 1 ;in which a spring is employed -as the means for urging ;the 'stop member towards the inoperative position. r

3` Front edge -detector mechanism as claimed in claim 1 in which the intermediate stop .mem- :ber comprises a lever of which one end makes the latehing engagement with the feeler and :the other end lies in the path of the sensing abutment ;as iaroresaid. i

ii. Front edge detector mechansm 'as claimed claim 3 in whieh :the intermediate :stop .lever extends .in the direction of the 'feed .of the .sheets rearwardly away .from the front days,

5. Front edge -detector meehanism as claimed .in claim '1 .in which the secondary means also constitute 'a i'c-setting device :operable .to are-set the intemediate member .into the ;operativ position between the .feeding of .successive sheets.

%6. ment edge .detector mechanism as claimed in claim ;5 in -which the secondary 'means ;comprise a be-I'l-erank -o-f which 'one 'arm is arranged ;for enga'gement by the -sensing member near the ena of the backward strokes thereof and the hell-emm: is thereby g iven a movement of 'rotahon .about its `pivot and the 'other arm is arran'ged such .rotation to pese-t the 'intermediate mem"- b'er into the operative position.

7 a sheet *reading mechanism of the dethe stop end scribed and having a layboard, which mechanism embodies front edge detector mechanism comprising a support arm, extending over the layiooard, a feeler pivotally attached to one end of the arm and dependent therefrom, a primary lever exte'nding lengthwise of the arm and pivoted thereto intermediate in the length of the lever, one end of the lever making releasable latching engagement with the feeler to prevent upward movement of that end of the lever and the other end of the lever constituting a stop, spring means constantly urging the first mentioned end upwardly against the latching engagement with the feeler, a sensing arm arranged for constant oscillation towards and from the stop end of the lever which end, when the lever is in the latched position, lies in the path of the sensing arm on its forward stroke to stop movement thereof but may be moved clear thereof by the spring means when unlatched, and a secondary lever pivoted to the support arm adjacent of the primary lever and having two arms of which one underlies and is adjacent to the stop end of the primary lever and the other lies in the path of the sensing arm towards the end of its backward movement whereby when the sensing arm is at the backward end of its movement the secondary lever is rotated by the sensing arm to engage and raise the stop end of the primary lever thereby to reset the lever to the latching position and also temporarily to support the primary lever and to relieve the feeler of frictional engagement with the primary lever to allow the feeler to be freely moved by a correctly placed sheet.

8. Front edge detector mechanism for sheet feeding apparatus of the kind .described and embodying a layboard and front lays up to which the front edge of each sheet in turn is moved for registration, said mechanism eomprising a feeler in the form of a pivoted arm arranged to be partially rotated about its pivot by engagement with the front edge of each sheet in turn as it approaches the front lays, a sensing member providing a sensing abutment thereon to be constantly oscillated in timed relatio-nship with the' feeding of the sheets, a stop member intermediate between the feeler and the sensing abutmentand having a releasable latching engagement with the feeler by which the stop member is held in a position in which it lies in the path of the sensing abutment and is operative to engage the abutment and to stop the movement of the sensing member, the latching engagement being releasable on movement of the feeler as aforesaid by a correctly timed sheet, means for constantly urging the stop member against the latch control of the feeler to a position in which the stop member lies outside the path of the sensing abutment and is inoperative to stop the sensing member, and secondary means operable by movements of the sensing member to reset the stop member to the operative position between the feeding of successivo sheets.

GEORGE WILLIAM TEBBS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 'Name Date 625994 Dexter May 16, 1899 '765,414 Dexter July 19, 1904 1,603,349 Marquardt Oct. 19, 1926 2,433,120 Harrold Dec. 23, 1947 FOREIGN PATENTS Number Country Date 20,685 Great Britain Sept. 19, 1912