Nov» 5,1946. |_. M. PQTTS ~ 2,410,521 . TAPE FEED ALARM Filed May 22, 1942 - ' IiNVENTOR. LOUIS M. POTTS , Patented Nov. 5, 1946 2,410,521 UNITED J STATES PATENT, j OFFICE ‘TAPE FEED ALARM ’ Louis M. Potts, Evanston, 111., assignor to Teletype Corporation,v ‘Chicago, 111., a vcorporation of Delaware ' > ‘Application May 22, 1942, Serial No. 444,067 13 Claims." (oi. 177_311> 1 - 2 This invention relates to telegraph transmit tingapparatus and particularly to a strip feed alarm device for indicating the manifestation of order that the operator may know in which par ticular one of the. transmitters the condition’ defective strip feeding conditions. exists. The invention ,, . will be more readily , understood . V by reference to the following detailed description In the telegraph communication ?eld, tape is employed as a medium for carrying indicia of and the drawing wherein, telegraph signal code combinations, usually in the form of permutably arranged perforations. Ordinarily, the tape is ?rst perforated either by ' , ' Fig. 1 is a perspective view of oneembodiment of the present invention partly‘ in section: and with certain portions of the apparatus omitted for the sake of clarity; . _ _ j q 7 means of key operated perforator or by means of Fig. 2 is a plan View of the embodiment of the a signal controlled reperforator and later used in invention disclosed in Fig. 1; ' ' ’ connection with a tape transmitter to send sig Fig. 3 is a schematic representation of thecams nals in code combination form overv an outgoing line. The tape, in performing its operating func used in connection with'the invention?disclo'sed‘ tions, is subject to stresses and strainswhich may 15 Fig. 4 is a plan view ‘partly in section of a- sec at times cause the tearing of the feed holesand possibly a complete rupture of the tape. 'Itvis ond embodiment of the present invention; ‘ _ in.Figs.1and2;- . ., , ' . Fig. 5 is a side view partly in section of the apparent that any such undesirable conditions may seriously impair transmission of messages apparatus disclosed in Fig. 4;’ and ‘ Fig. 6 is a perspectivejview of the cam control and cause distortion or loss of signals, particu 20 larly so if such conditions were not immediately means employed in theembodiment of theinven tion disclosed in Figs.3vand ‘l. _ f ' g recti?ed. The use of tape-operated transmitters - Referring [now 'to vthe drawing, '' the first which are ‘unattended by an operator is growing embodiment of the invention which is disclosed constantly and consequently the desirability of the arrangement as herein provided is enhanced 25 in Figs. 1, ,2, and 3 will now be described'in detail. The present invention-may be conven-l inasmuch as the problem of defective tape feed iently incorporated for use withtape transmit ing conditions is obviously not as serious when a ters such as disclosed‘ in, the patent to transmitter is under the constant surveillance of >Goetz', PatentNo. 2,296,845 issued September 29, an operator. It is therefore the prime object of this inven 30 1942, and in order to facilitate. the descriptionvof the present application'it will‘be, presumed ‘that tion to provide a mechanically controlled‘ strip feed alarm which immediately brings to an oper the ratchet wheel ‘56 disclosed therein¥ the'shaft, 58 which carries the ratchet 56, and the sprocket, ator's attention the manifestation of adefective tape feeding condition. 7 Other objects, features and advantages of the 35 present invention will become evident as the in vention is further described in detail. By the present invention there is provided a. mechanically controlled alarm device in which two contact operating. levers are normally main tained in'inoperative positions by a cam arrange- ‘ ment and wherein a relative displacement of the cams included in the arrangement when defective tape feeding conditions occur, causes one or the wheel 59 are the same as the similarly numbered elements appearing in the present disclosure. As described in detail in the just referred to patent,v the tape is intermittently fed forward as :the ratchet 56 is‘ periodically advanced by manger a pawl iassociated with'a stepping‘i?agnet which thereby causes'the rotation of the shaft'58faifdv the tape feed sprocket 59. In, the present revels, ti'on' there is attached to the shaft 58 by meansv of a set screw 60 asleeve' 5| which ?xedly carries‘ a pair of cam members 62-and 63 which are thus other of the levers to operate both an audible‘ 45 and a visible signaling means. The use of both audible and visible signal indicating means in the mounted for rotation with the shaft 58. ' present invention is particularly desirable in view of the fact that the apparatus heren disclosed is designed especially for usein installations which 50 sprocket 65 which is frely rot'atable'about ashaft 6% which is suitably mountedvinthe transmitting apparatus.‘ The sprocket '65 is attached to the may include a large number of transmitters. sleeve 6'! and rotatable therewith‘ about the shaft It ' ' > ‘ To the rear of the feed sprocket 59 directly in alignment therewith is provided a second ‘feed, is therefore necessary to bring to the operator’s 56. Carried at the end of the sleeve 61 opposite 1 attention not only an indication of the occur the sprocket 165 is apair of cams 68 ‘and 69 which are similar in con?guration to the cams 62 and‘ rence of a defective feeding condition by an audi ble signal but also by a visible signal as well in 51.5 53 Whichvwere previously described. , _ 2,410,521 3 4 Referring now again to the shaft 58 (Fig. 2) as long as the tape H0 is being fed forwardly by sprocket 59 and the sprocket 65 is being ro tated through the intermittent pull of the tape H0, the levers ‘l3 and 83 will be retained in a clockwise position. This is due to the fact (re ferring ?rst to lever 73) that cams 62 and 63 when in phase relationship with camsl68 and 69 are it can be seen that there is carried thereon for rotation therewith a gear ‘H which drives an idler gear 12 which in turn drives a gear 64 which is ?xedly attached to the shaft 65. It is there fore apparent at this point that as the sprocket feed wheel 59 intermittently advances the tape H0 forward, the pull of the tape enables the second sprocket wheel 65 to be also intermittently advanced inasmuch as the feed holes of the tape are positioned on the pin projections of both sprockets. It is therefore further observable that inasmuch as sleeve 61 is attached to sprocket 65, as sprocket 65 is advanced, the sleeve 6:! will also be advanced and will carry the earns 68 and 69 so arranged that the high portions of the cams work alternately against the upstanding arms 15 and 14. Cams 63 and 69 are normally so posi , tioned that when the end of arm 15 has been traversed by a high portion of the cam 63 the other arm 14’ will have already been engaged by the" high portion of cam 69. Lever 94 is con trolled in a similar manner by its associated cams and-it is therefore apparent that as long as op erating conditions are normal, neither one of the levers 13 or 83 will be allowed to pivot and close the contacts 9| to cause operation of an alarm device to be hereafter described. Should a break with it during its advancing operations. At the same time it will be noted that the pair of cams 62 and 63 which are carried by the sleeve 6| mounted on shaft 58 will likewise be intermittently advanced so that a phase relationship will be normally maintained betweenthe'two sets of age of tape occur, shaft 58 will continue to rotate cams. with'rs'haft 58 and cam 69 associated with shaft 66 in a contact operating lever 13 which has an and drive the cams 62 and 63 while the sprocket 65 will no longer rotate inasmuchas the tape no longer exerts a pull thereon,'and therefore cams 68 and 69 come to a stop. At'this time either one or the other of the arms 14 of lever 73 or the arm 84 of the lever 83 rests on a high portion of the cam‘ while the other arm is positioned over a low portion of the cam. Therefore, if for instance ' upstanding arm 14 adapted to cooperate with the arm 74 of lever 13 were over a low portion of cam It will be understood that the gear ar rangement will be such that sprockets 59 and 65 will be intermittently rotated thesa’ine relative distances during normal operation of the appa rains- c , , , “Mounted in alignment with cam 63 associated cam 69 and a second upstanding arm 15 adapted 69 when shaft 66' came to a halt then when cam to cooperate withthe cam 63. A horizontally ex tending arm 16 of the lever 13 is in engagement with an insulating portion 11 of a contact spring 18 which is normally ‘spring urged away from its 63 is in a position whereat the arm 15 may on gage a recessed portion of its cam, the lever 13 would be able to pivot to a position under the in?uence of spring 8| to close the contacts SI and operate the alarm device. Of coursea simi associated spring contact member 19‘ The lever 13_'is normally urged to rotate in a counterclock lar condition would occur if the arm 84 of lever 83 came to a position overlying a recessed por tion of cam 68 when the shaft 66 came to a stop. wise direction about vpivot shaft 82' as viewed in Fig: 1 under the'in?uenc'eofspring 8| so that the upstanding ‘projection 15 and the upstanding - projection 14 are urged into engagement with The pair of earns‘ 68 and 69 are provided with raised portions slightly less than 90 degrees and with recessed portions slightly more than 90 de their associated cams. Also mounted upon the shaft 62 is a second lever 83 which is exactly the samein construction’ as the just described lever grees with the ‘high portions of‘ one cam adja cent the low portions of the other cam. This 19.“ Upstanding portion 84_ of lever 83‘ is adapt enables an overlapping cooperation of the high ed-to cooperate with cam 68 while the upstand portions of cams 68 and 69 with the high por ing arm 85 of lever‘ 83 is adapted to cooperate tions of cams 62 and 53, respectively, which, as with the cam 62 and the horizontallyextending already mentioned, are slightly in excess of 90, degrees to normally hold levers 13' and 83 in arm» 86Vis: adapted to cooperate with the insulat inglport'ion _'l_'l of contact spring ‘I8 in a similar 50 their respective inoperative positions when oper manner to the horizontally extending arm 16 of at'ing in proper phase relationship. Due to the leverr‘ir3 and likewise _a spring 81 normally urges fact that cams 68 and 69 are staggered with respect to each other, that is, with the slightly lever-v83’ in awcounterclockwisedirection as viewed in Fig. -1. The contact spring_'!8- is therefore under 90 degree high portions of one cam adja common to and operable by either lever 13 or , cent the slightly more than 90 degree low portions of the other cam, it is always assured that the I 'iIgfheraisedportions qf-cams 62 and 63 will be cam engaging portion of one ofthe levers ‘I3, slightlyin excess of 90 “degrees of their respective 83 will overliea low portion of one of the cams peripheralcontours (Fig. 3) while the recessed 68,769 when they cease to rotate as explained, portions of the cams will be slightly less than 90 degrees of their respective peripheral con tours andqtheicams? and 63'will be so positioned with relation to each otherthat the high portions 60 andis thus enabled to pivot-and operate the alarm device ‘irrespective of the stop positions of cams 68 and 69. The closing of the contact pair 9! completes of one cam will be opposite the low portion of the thealarm circuit over conductors 92 and 93 so other cam- as shown in Fig. 1,‘for apurpose which that an audible signal 94 and the visible signal 95 are placed into operation and will be periodi will hereafter appear. The high portions of cams 69 and 69Bwill~ consist of segments of slightly cally operated thereafter as the shaft 58 con lessthan 90 degrees of- the peripheral contour tinues to rotate to cause a periodic movement or the particular lever whose upstanding arm, of the cams-While the recessed portions of these cams will be slightly in excess (Bf-'90 degrees of 70 ‘M4 or ‘812' was opposite a low portion of the cam theperipheral contour of the camsand the raised when, the shaft 66 came to a stop. The attend portions of cam vI58 will be positioned adjacent ant» at this time will thus be informed that a the recessed portions of cam 59 as clearly shown defective tape feeding condition has occurred and 'inFig. 1. It can now be seen by referring to Fig. 1 that will ‘then immediately be able to rectify the 'con diiion, 2,410,521; 5 In order to reset the cams 68 and 69 into phase‘ relationship‘ with the cams 62 and 63, a special reset mechanism is provided which will nowbe described. In tape transmitters such as dis closed in the Goetz-patent, already referred to; there is provided a bar I08 which is similar to the bar I08 disclosed in Figs. 1 and 2 and which is employed at the start of transmission tocon dition the apparatus for operation. Adjacent to the bar I08‘ is suitably mounted a bracket I09 which carries a U-shaped lever III which is pivoted at H2 and carries an extending'arm H3. Lever III is normally urged in a counter clockwise direction by spring I20 asv viewed in Fig. 2., The upper and lower arms H8 of the U-shaped member terminate in a rounded por now be described. This second‘ embodiment‘of the invention may also be readily incorporated ‘ into the previously referred to transmitter dis closed in the Goetz patent. It will be presumed that ratchet wheel I56 is equivalent to the ratchet wheel 56 shown in Figs. '1 and 2 and likewise the shaft I58 and feed sprocket I59 are equivalent to shaft 58 and the feed sprocket 59, respectively, as disclosed also in Fig. 1. It had been previously mentioned that the parts 56, 58, and 59 of Figs. 1 and 2 were numbered similarly to the like parts appearing’ in ‘the Goetz patent. Shaft I58 will be suitably journaled in the frame_and will be intermittently advanced by the engagement of a stepping pawl with the ratchet I56 as is well known in the art. The tape I6! will be threaded over the teeth of the feed sprocket I59 and will tion I I5 which rides in a groove of a collar mem he therefore intermittently advanced as the ber H6 which is suitably keyed to a slot H1 in ratchet I56 is actuated. Carried at the end of the shaft 66 and rotatable therewith. The collar, member I I6 includes a pair of disc like side mem 20 shaft I58 opposite to the ratchet I56 is a gear I62 which drives a suitably mounted idler. gear bers I2I and I22. The disc member I22 has I63 which in turn causes the rotation of a driving struck up therefrom an upstanding projection gear I64. ‘ In mesh with the driving gear I64 is a I23 adapted to cooperate with two pins I24 and second idler gear I65 which drives the gear I66. I25 carried by sprocket 65 in a manner to be immediately hereafter described. 25 Integrally formed with the gear member I64 is a sleeve I61 which carries a cam member I66 The ,U-shaped member III which is mounted having a peripheral contour in which the raised upon bracket I69 is during normal transmission portion of the cam is slightly in excess of 180 restrained from movement by the abutment of degrees. The sleeve I61 is attached to the shaft projection H3 with an extending portion H4 of the bar I06. However, when it is desired to start 30 I69 by means of a set screw HI and it is thus obvious that the shaft I69'is rotatable with the transmission or to reset the tape sprockets into gear I64. phased relationship, the bar I08 is depressed and Also mounted upon the shaft I69 and freely the projecting portion H4 of the bar is removed rotatable thereon is a second feeding sprocket from the path of the projection H3 so that the U-shaped member III is then free to move in a 35 I12 which is directly in alignment with the ?rst feeding sprocket I59. It is therefore observable counterclockwise direction as viewed in Fig. 2. that as the tape I 6| is advanced by the ?rst feed under the influence of spring I20. This causes ing sprocket. I59 inasmuch as the tape by means the upper and lower arms H8 of the U-shaped' of its feed holes engages the teeth of the'second member III to shift the collar member II 6 axi feeding sprocket I12, the second feeding sprocket ally upon the shaft 66 along the keyway II1 to I12 will be rotated about'the shaft I69 by the pull its phasing position. ‘ of the tape. The feed sprocket I12 has integrally When inserting a new or an unused portion of formed therewith a sleeve I13 which surrounds‘ a broken tape, the operator depresses the bar the shaft I69 and carries a cam member I14 which I08 with one hand and with theother hand posi.tions the tape upon the sprocket 65 and there-, . has a peripheral contour in which the raised portion of the cam is slightly less than 180 degrees after with the same hand rotates the sprocket for a purpose which will hereinafter appear. 65 manually until sufficient tape has been fed When the tape is' properly advanced by the out for engagement with the main feeding sprock feeding mehanism, the cams I14 and I68 will be et 59. The sprockets 65 and 59 will be so placed with respect to each other that by the time. 50 so arranged that their high portions together present a 360 degree closed surface to the cam the tape has been positioned .upon the. front engaging portions I16 of a pair of levers I11 and sprocket one or the other of the pins’ I24 ‘of. I18 which are pivoted at I19 and I 8 I, respectively, I25 will have come into engagement with the and the came engaging portions I16 of which upstanding projection I23 of disc member I122 of collar member H6 which is carried by the 55 are 180 degrees apart and normally urged towards each other by means of resilient spring members shaft 66 and therefore the sprocket will again I 80 associated with contacts I83 and I64. The be returned to a phase relationship. This oc lower end portions of the levers» I11 and I19 curs when the collar member II6 assumes‘ its terminate in curved contact engaging portions phasing position as described above. Due to the fact that the collar H6 is rotatable with the 60 H9. These contact engaging portions >II9 are adaptablelton cooperate with contact members shaft 66, as the sprocket 65 is rotated manually I83 and I84 which control the alarm circuit. by the operator, a point will ‘be reached as ‘exe.v Normallyithe contact engaging portions II9 of plained wherein the pins I25 or' I24 will engagev the levers rest against the insulating‘ members with the projection I23 so that the sprocket 65 and the collar I I6 will thereafter rotate as a unit 65 I85 associated with the resilient spring members I80 of the contacts and hold the spring members and thereby the gear members 64, 1 I, and 12 will‘ in ?exed condition to thus urge the levers I11 be likewise rotated to therefore set in motion and I18 to pivot towards each other. However, ‘ the sprocket 59. It can thus be seen that by should a defective or irregular tape feeding con means of this mechanism the sprockets may be readily returned to their exact phase relationship 70 dition occur one or the other of the levers will which they will continue to maintain until the tape again breaks or for some other reason fails to advance the tape. . - - Referring now to Figs. 4, 5, and 6, the second embodiment of the invention herein disclosed will be‘ pivoted under the influence of the spring con tact members I89 as will laterv appear and will close one or the other of the contact members I83, I84;v The 'closure'of either of the contacts‘ enables‘ one ofthe parallel circuits I80 and I81 2,410,521‘ 7 to become effective to operate an audible alarm‘ device I88 ‘and the other to operate a signalllamp I89 which will announce to the operator the oc currence of a defective tape feeding condition. ' The operation of'the contact control levers I'll and I‘I8'will now be described in more detail. it will be presumed that the tape stepping sprocket I59 is in normal operation and is intermittently advancing the tape I6 I. If a breakage of thetape should now occur, the main tape feed sprocket I59 10 8 holes would not be centralized with respect to the teeth of the sprocket but would be pulled to one side by the teeth of 'the’sprocket. This would cause a slight misalignment of the signal per forations with the tape feelers and might impair the e?iciency of signal transmission. It will be understood that various changes and modi?cations may be made in the above-described speci?cation without departing from the spirit and scope thereof. , will continue to operate. However, due to the fact that the second tape feed sprocket'l ‘I2 is operated What is claimed is: 1. In a tape feed alarm, feeding means for by the pull of the tape it will come to rest. There advancing a strip, a cam mechanism, means for fore, inasmuch as the cam I14 is carried by the operating said cam mechanism under the joint sleeve I73 which is connected to the feed sprocket 15 control of said strip and said feeding means, an I12, this cam will likewise come to rest. 0n the alarm device, a pair of levers controlled by said other, hand, the cam I68 will continue to rotate cam mechanism for operating said alarm de by means of the drive aifo‘rded by the'gear's I62, vice, and‘means included in said cam mechanism I63, and I64. In view of the fact that the high for enabling the operation of one of said levers portion of the cam H4 is slightly less than180 upon the failure of said strip to exercise control degrees and the cam engaging portions‘IlS of of said cam mechanism to thereby enable actu the levers IT! and I78 are 1801degrees apart, one ation of said alarm device which of said levers of the levers will be held in its outer position‘by being actuatable depending on the phase posi engagement with the ‘high portion of cam I'M. tioning of said cam mechanism. When the cam comes to rest, While the other leverv 2. In a strip feed alarm, feeding means for will be opposite the low portion of the cam and advancing a strip, a ?rst pair of movable cam when the cam‘ I68 is in a position to also present members, means for moving said ?rst pair of its low portion to this last mentioned lever, the cam members in synchronism with the movement lever will be permitted to carry its‘cam‘ engaging of the strip feeding means, a second pair of portion H6 inwardly under, the in?uence of its 30 movable cam members, means for moving said associated spring contact member 586, enabling second pair of cam members in synchronism with its contact engaging portion H9 to operate‘ its the movement of said strip to maintain a phase associated contact member I83. The alarm relationship with said ?rst pair of cam members, device will then thereafter be intermittently and an alarm device controlled by said pairs of operated" as the cam I68 continues to rotate and 35 cam members, whereby said alarm device is op present its low portion to the lever whose cam erated by said pairs of cam members when said engaging portion I76 happens to' be opposite the low. portion of the cam I16. This condition will continue until the operator has made the neces sary‘corrections in the apparatus. 7 ‘ 'It'will be understood that a similar resetting mechanism which was described in connection with Figs. 1 and 2 could be readily incorporated‘ into the embodiment of the invention disclosed ‘ in Figs. 4, 5, and 6 by mounting a collar member such as II6 disclosed in Fig. 2 upon the shaft strip fails to maintain said phase relationship 'between said pairs of cam members. 3.1In ‘a strip feed alarm, feeding means for advancing a strip, a ?rst pair of movable cams, means for moving said ?rst pair of cams in syn chronism with the movement of the strip feeding means, a second pair of movable cams, means for moving said second pair of cams in phase with said‘?rst pair of cams andv in synchronism with the'movement of said strip, a pair of levers each I69 and providing the other necessary equipment controlled by a cam of each pair of cams, and which has already been described. . an‘ alarm device operable by either of said levers, The purpose of providing the additional’ idler whereby one or the other of said levers is actu gtar I65 and the additional driven gear' I66 in 50 atable to operate said alarm device when said mesh therewith is to enable the rotation of a suit pairs of cams are not maintained in phase by said ably journaled shaft 192' which carries a third strip; which of said levers being actuatable de feeding sprocket I93. As shown in the drawing, pending on the phase positioning of said earns. the third‘feeding sprocket'l63 is in direct align? '41 In -'a strip feed alarm, feeding means for ment with the feeding sprockets I59 and I12 but‘ advancing a strip, a ?rst pair of movable cams, is in a slightly elevated position with respect a second pair of movable cams, said ?rst pair of thereto. The purpose of this arrangement is tov cams moving in synchronism with the movement enable a considerable portion of the tape to move of the strip feedingmeans and said second pair over' the periphery of the feed sprocket R93 to ofscamsmoving in phase with said ?rst pair of thereby enable a better distribution of strain upon 60. cams and in synchronism' with the movement ofv the‘tape. A strain relieving sprocket is partic said strip, an alarm device, and a pair of levers ularly desirable in cases where the tape may be to control said alarm device, each of said levers fed from arelatively large supply reel and in cases? being alternately controlled‘by a single cam of wherein it makes for better operation of the tape each pair of cams, whereby one or the other of transmitter to remove the strain from'the tape said levers is actuatable to operate said alarm de prior to the movement of the tape into the trans vice. upon the failure ofisaid strip to maintain mitter proper where it performs its transmit said phase'condition of said cams, which of said ting operations. One particular advantage of levers "being actuatable depending on the phase this is that it enables the centralization of the positioning of said cams. ' > feed holes of the tape upon the teeth~=of the 70' .5. In a strip feed alarm, feeding means for sprocket wheel thus assuring the correct align-' advancing a strip, a ?rst movable cam, means ment of the signal-perforations "of the tape'with , for moving said ?rst cam in synchronism with the sensing mechanism commonly’ employed in, the movement of the strip feeding means, a raised tape transmitters. If a strain were placed. upon portion on said cm, a second movable cam, the tape at the main feeding sprocket, the feed. 1 means for‘ movingsa‘id second‘ cam in phase with. ' 2,410,521 10 the ?rst cam and in synchronism with the move ment of said strip, a raised portion on said sec ond cam, an alarm device, and a pair of levers depending on the phase positioning of said cam means. 10. In a tape feed alarm, feed means for ad vancing a tape, a ?rst movable cam means, means for moving said ?rst cam means in syn each having a portion engaging with said cams, whereby said raised portions of said cams are nor mally positioned with respect to each other to chronism with the movement of said tape feed present a closed peripheral surface to said cam - means, a second movable cam means, means for engaging portions of said levers while said phase condition is maintained to normally prevent op eration of said levers, whereby one or the other of said levers is operative to control said alarm device upon the failure of said strip to maintain moving said second cam means in synchronism with the movement of said tape and in phase 10 with the operation of said ?rst cam means, each said ?rst and second cam means provided with complementally related peripheral contours, lever said closed peripheral surface of said cams under means in contact with both said cam means, and an alarm means controlled by said lever means said phase conditions, which of said levers being actuatable depending on the phase positioning of which is ineffective when the complemental pe said cams. ripheries of said cam means are in phase and 6. In a tape feed alarm, feeding means for advancing a tape, a shaft for driving said feed ing means, a cam member carried by said shaft, said cam means are out of phase. effective when the complemental peripheries of 11. In a tape feed alarm, feed means for ad vancing a tape, a ?rst movable cam means, means for moving said ?rst cam means in syn_ chronism with the movement of said tape feed means, a second movable cam means, means for moving said second cam means in synchronism a second shaft, a second cam member carried by said second shaft moving in sync'hronism with said tape to maintain a phase relationship with said ?rst cam member, and an alarm device con trolled by said cam members, whereby said alarm device is operable under the control of said cam with the movement of said tape and in phase members upon the failure of the maintenance of with the operation of said ?rst cam means, each said phase relationship between said cam mem' said ?rst and second cam means comprising a bers. pair of cams, corresponding ones of which are 7. In a strip feed alarm, feeding means for provided with complementally related peripheral advancing a strip,. a shaft, a pair of movable 30 contours, and an alarm means ineffective when cams carried by said shaft and operated by said the complemental peripheries of said correspond feeding means, a second shaft, a second pair of ing cams are in phase and effective when the movable cams carried by said second shaft and complemental peripheries of said corresponding moved in phase ‘with said ?rst pair of cams in cams are out of phase. , synchronism with the movement of said strip, a 1 12. In a tape feed alarm, feed means for ad pair of levers each controlled by a cam of each vancing a tape, a ?rst movable cam means, pair of cams, and an alarm device operable by means for moving said ?rst cam means in syn either of said levers, whereby one or the other of chronism with the movement of said tape feed said levers is actuatable to operate said alarm de means, a second movable cam means, means for vice when said pairs of cams are not maintained moving said second cam means in synchronism, in phase by said strip, which of said levers being actuatable depending on the phase position of said cams. 8. In a tape feed alarm, feeding means for advancing a tape, ?rst movable cam means, . means for moving said ?rst cam means in syn chronism with the movement of said tape feed with the movement of said tape and in phase with the operation of said ?rst cam means, each said ?rst and second cam means provided with complementally related peripheral contours, a pair of levers each jointly controlled by said ?rst and second cam means, and an alarm means operable by either of said levers, whereby one ing means, a second movable cam means, means or the other of said levers is actuatable to oper for moving said second cam means in synchro— ate said alarm means when the complemental nism with the movement of said tape to main 50 peripheries of said cam means are out of phase, tain a predetermined relationship with said which of said levers being actuatable depending ?rst cam means, an alarm device including elec on the phase positioning of said cam means. trical contact means, and a pair of levers each 13. In a tape feed alarm, feed means for ad engaging both of said cam means whereby when vancing a tape, a ?rst movable cam means, said phase relationship fails between said ?rst 55 means for moving said ?rst cam means in syn and second cam means one of said levers closes chronism with the movement of said tape feed said electrical contact means to cause said alarm means, a second movable cam means, means for device to operate, which of’ said levers being ac moving said second cam means in synchronism tuatable depending on the phase positioning of said cam means. 9. In a tape feed alarm, feeding means for advancing a tape, a ?rst movable cam means, means for moving said ?rst cam means in syn chronism with the movement of said feeding with the movement of said tape and in phase 60 with the operation of said ?rst cam means, each said ?rst and second cam means comprising a pair of cams, corresponding ones of which are provided with complementally related peripheral means, a second movable cam means, means for 65 contours, a pair of levers each jointly controlled moving said second cam means in synchronism by one of said pair of cams of each of said ?rst with the movement of said tape to maintain a predetermined phase relationship with said and second cam means, and an alarm means operable by either of said levers, whereby one or the other of said levers is actuatable to operate ?rst cam means, an alarm device including elec trical contact means, and a pair of levers jointly 70 said alarm means when the complemental pe ripheries of said corresponding cams are out of controlled by both of said cam means, whereby phase, which of said levers being actuatable de when said phase relationship fails between said pending on the phase positioning of said cam cam means one of said levers closes said elec trical contact means to cause said alarm device means. to operate, which of said levers being actuable 75 LOUIS M. POTTS.