US2373132A - Telegraph key - Google Patents

Description

l0, J. F. MacADAM TELEGRAPH KEY Filed Oct. 22. 1942 3 Sheets-Sheet 1 Apfil 10, 1-945.

gllllllll 74 jgnnnnri J. F. MacADAM TELEGRAPH KEY Filed Oct. 22. 1942 3 Sheets-Sheet 2 J. F. MacADAM TELEGRAPH KEY A fil 10, 1945.

Filed Oct. 22, 1942 f] 46 n l I $8 H I l H 3 Sheets-Sheet Patented Apr. 10, 1945 UNITED STATES ir 'riTENT OFFICE TELEGRAPH KEY James F. MacAdam, Arthur, N. Dak.

Application October 22, 1942, Serial No. 462,955 19 Claims. (Cl.:17882) This invention relates to telegraph keys and has special reference to so-called semi-automatic keys arranged to make successive dots or dashes in response to a single manual manipulation of the keys,

An important object of the invention is the provision of a key 'of simplified construction ar-- ranged to make successive dots of substantially uniform duration in response to manipulation of the paddle in one direction and successive dashes of substantially uniform duration when the paddle is moved in another direction.

Another object of the invention is the provision of a semi-automatic key of simpler construction and greater ease of operation capable of transmitting more nearly perfect signals than prior keys of this class and by means of which less skill is required to send easily read code signals and highly skilled operators can attain higher speeds.

A further object of the invention is the provision of an automatic key in which individual dashes or the last of a series of dashes can be shortened somewhat without materially disturbing the readability of the code. I

Another object of the invention is the provision of a semi-automatic key in which both dashes and dots are sent by operation of a single pair of contacts biased to a closed position and opened by operation of a pendulum manually controlled to swing through difierent periods to produce either dots or dashes.

I have also aimed to provide a semi-automatic key having novel means for supporting and actu ating the pendulum to control the period during which a pair of contacts are caused to remain closed. i

A further object is the provision of a semi-automatic key wherein a pendulum acts to open a pair of contacts to produce a uniform period between signals and swings free of engagement with the contact mechanism for selectively different periods in order to form the dot or dash interval.

A further aim is to provide a key having a novel contact device designed to minimize rebounding of the contact at the time of closing.

Other objects and advantages will appear from the following discussion and the accompanying drawings, in which Figure l is a side elevation of a key embodying my invention;

Fig. 2 is a top view thereof;

Fig. 3 is a longitudinal section through the key mechanism of one form of the invention;

Fig. 4 is an expanded side view of the pendulum and pendulum latching mechanism of the form shown in Fig. 3;

Fig. 5 is a section on the line 5-5 of Fig. 3;

Fig. 6 is a diagrammatic view showing the relationship in the time intervals as between the dots, the dashes, and the spaces;

Fig. '7 is a section substantially on the line 'l! of Figure 1 showing the preferred form of the invention and showing the parts in the rest position;

Fig. 8 is a section similar to Fig. 7 showing the parts in the position for producing dots with the pendulum at the back of its swing;

Fig. 9 is a section similar to Fig. 8 showing the pendulum atv the opposite end of its swing in a position to open the contacts;

Figs. 10, 11 and 12 are views similar to Fig. '7 showing the parts in the positions for making dots with the pendulum at successive positions of its swing, and

Fig. 13 is a section on the line l3l3 of Figure 1 showing the form of the contact vibration damper.

In the transmission of telegraph code such as Continental code for which this key is primarily intended, the signal is produced by the'closing and opening of a switch or switches to produce various combinations of long and short signals separated by spaces, the long and short signals commonly being referred to as dots and dashes. The dashes should be approximately the length of the dots and the space between any of the dots, dashes or dots and dashes in any one character should be equalto the length of one dot. Therefore, a telegraph key transmitting a series of dots should leave intervals between the dots equal in length or duration to that of one dot as indicated at A in Fig. 6. In a series of dashes the intervals between the clashes should be the same as the interval between the dots (assuming the same transmitting speed) as indicated at B in Fig. 6. In addition, the length of the dashes should be substantially three times the length of the dots, or in other words, the length of the dash such as the dash C of Fig. 6 should be the length of two dots such as the dot D- and the intervening space E. With the construction herein shown and described this relationship is substantially maintained with the exception that in this construction individual dashes or the last of a series of dashes can be somewhat shortened and less skill is required to send easily read code signals than prior devices.

Directing attention now to Figs. 1 and 2, the

key includes a base indicated generally by the numeral 13 carrying suitable feet as shown at l4 and having a pair of spaced upwardly projecting rods i5 and i6 rigidly carried thereon. For structural reasons a plate 11 may be disposed on top of the base 63 below the rods I5 and I6, and a triangular plate I8 is attached to the upper end of the rods l5 and I6 as by means of screws l9. Positioned on the plates I! and I8 are pivot bearings 2i and 22 between which is pivotally disposed a vertical pin 23 in a plane intermedi ate the rods l5 and I6 as will be apparent from Fig. 2.

A frame is arranged to be supported on the pivot pin 23 and comprises a channel member of substantially U-shaped cross-section disposed on its edge and having openings on its side flanges 24 and 25 for the passage of the pivot pin 23, a screw 26 (Figs. '7 to 12) being threaded into the base 21 of the channel and engaging the pivot pin 23 (through a spring member presently to be described) to retain the frame in fixed position on the pin. Attached to the base 21 of the channel by means of a screw 28 and spaced therefrom by a washer 29 i a flexible pendulum supporting springs 3 I, the spring extending rearwardly to a point between the screw 26 and the pivot pin 23 and extending forwardly slightly beyond the end of the frame. Attached to the forward end of the spring is a rigid block 32, the block being riveted or otherwise fixedly attached to the forward end of the spring as shown at 33 against a boss 34 such a to provide clearance between the block and the spring. At the rear end of the block 32 is attached a more rigid spring member 35, which spring member extends forwardly in parallelism with the block and with the forward end of the spring 3|, this spring being riveted or otherwise fixedly attached to the block against a boss 36 to provide clearance between the block and the spring for vibration of the pendulum as will presently be apparent. The forward end of the spring 35 has fixedly attached thereto a pendulum 31 in the form of a lon slender but rigid rod, the pendulum being adapted to vibrate in a horizontal plane as will presently be more fully described. Threaded into the base of the channel is a screw 38 carrying a, lock nut 39 for locking it in fixed position, the end of the screw being conical as shown at 4| to pass through an opening in the spring 3| and normally adjusted into face contact with the block 32 but not so as to change its position. The sides 24 and 25 of the frame are joined at their open edges by a lip 42 which carries an adjusting screw 43 and lock nut 44, the end of the screw being pointed as shown at 45 to-pass through an opening in the spring 35 and to engage the opposite face of the block 32. The screws 38 and 42 are so adjusted that when the pendulum is at rest' the ends of these screws contact the block' 35 but permit the block to remain in parallelism with the springs SI and 35 as shown in Fig. '7.

The pendulum rod 31 extend to a point adjacent one end of the base l3 and adjacent a vibration damper comprising an upright post 46, the upper end of which is slotted and carries a transverse pin 4'! on which is loosely mounted a roller 43 having lost motion with respect to the pin, the end of the pendulum coming into contact with the roller 48 in certain positions to dampen its motion. A weight 49 is adjustably carried on the pendulum rod and can be set in various positions longitudinally thereof in order to control the period of vibration at the pendulum. Threaded into the pendulum rod 31 is a screw 5| having a lock nut 52, the end of the screw 5| having a point 53 formed of insulation material and positioned to engage the end of a spring contact leaf 54, this leaf carrying a contact 55 adapted to cooperate with a contact 56 for closing and opening an electrical circuit to produce the signals in accordance with the usual practice. The contact 56 is attached to a bus-bar 51 which is in turn connected to a conventional binding post 58 located on the base IS. The flexible contact leaf 54 is likewise connected to a bus-bar 59 attached to a binding post 6| on the base, the binding posts 58 and 6! being, of course, insulated from the base. It will be seen that with this construction the pendulum and the remainder of the mechanism is electrically isolated from the circuit, the current passing between bus- bars 51 and 59 through the contacts. Also attached to the bus-bar 59 is a vibration damper comprising a strip of thin flexible spring material 62 extending along the Side of the contact leaf 54, the end of thi spring riding on one side of the leaf as shown at 63, the spring member being bent down in the form of a leaf and having a portion 64 engaging the opposite side of the contact leaf so that the contact leaf is pinched between the portions 63 and 64 but is free to slide as the pin 53 acts to flex the contact leaf 54. This causes a damping of any free vibration on the part of the contact leaf and prevents arcing and spitting at the contacts.

An actuator lever designated generally by the numeral 35 is supported between the sides 24 and 25 of the frame by means of spaced cars 66 on the lever and apin 61 passing through the sides of the frame as best shown in Figure 1. This lever ha a forward end 66 extending to a point opposite the rear end of the block 32 and has a rear end projecting backwardly as indicated at 69 having attached on opposite sides thereof leaves H of insulation material forming a paddle for actuation of the key. The lever also has a screw and lock nut 72, the screw projecting through a opening 1'3 in the frame and carrying a spring 15 soldered or otherwise attached to the lever and converging inwardly for engagement by the end 14 of the screw to urge the screw and actuating lever toward the right facing the figures. This causes the end 68 of the lever to maintain a slight pressure against the block and keep the block against the pendulum stops when the handle is released. This spring also permits of adjustment of the force required to make dashes and also prevents lengthening of a dot Or the last of a series of dots.

Threaded into the upright rods l5 and [6 are adjusting screws 16 and 11 provided with lock nuts for retaining them in position, the screw Tl carrying a nut 18 against which a spring 19 bears, the opposite end of the spring bearing against the base portion 21 of the frame so as to normally urge the frame in a clockwise direction facing Figs. 7 through 12. The screws 16 and 11 are adjusted so as to provide slightly greater space between them than occupied by the key mechanism so that the frame can rotate through a small amplitude about the pivot pin 23.

Operation The structure is so devised that as the paddle H is moved to the right, a dot or a series of dots are produced dependent upon the length of time the paddle is held in this position. Thus movement of the paddle to the right causes actuating lever 65 and the frame to rotate the pivotal center 23 because the front end 68 thereof presses against the rear end of the block 32. The pressure on the block 32 holds the block firmly between the adjusting screws 38 and 43 so that the stiff spring 35 only is allowed to flex with movement of the pendulum 31. This movement of the paddle causing the frame to pivot about the pivot pin 23, compresses the coil spring 19'and causes the frame to strike against the end of the screw 11, bringing the pendulum to the neutral position indicated by the dot and dash lines of Figs. 8, 9, and 12. This swing of the frame and the attached pendulmn, together with the sudden stop when the frame strikes the stop screw 11 causes the pendulum to oscillate from the rest position shown in Fig. '7, through the neutral position and then to the position shown in Fig. 8 which shows the pendulum in the extreme forward position of its swing, during which movement the contacts close approximately when the pendulum bar reaches the position indicated by the dot and dash line in Fig. 8. Thereafter the pendulum returns in the back stroke of its swing to the position shown in Fig. 9 coincidentally en'- gaging the contact leaf 54 when the pendulum returns to the position .indicated by the dot and dash line and moving the contact 55 out of engagement with the contact 56. The precise point in the pendulum swing at which contacts will open and close may be regulated by adjusting the screw 5|. It will beseen that since the stiff spring 35 only is in operation the half of the oscillation cycle represented by the distance from the center line 8| of the pendulum swing to the full line position of Fig. 8 is completed in the same time as the half of the cycle represented by the distance between the center line 8| and the full line position of Fig. 9. Thus the insulated tip 53, oscillating with the pendulum, opens the contacts for approximately half of each cycle. This action produces dot signals with spaces. approximately equal to the length of the dots. If the control paddle is held in the dot position the pendulum continues to oscillate, producing a series of dots, until the energy of the pendulum and the spring 35 is exhausted or until the paddle is released; When the paddle is released the spring 15 acts to hold the end of the actuating lever 65 tightly pressed against the block 32 and the block is therefore locked in position as the pendulum and the frame return to the neutral position. It is important that the various adjusting screws 38, 43 and 12 be so set that the block 32 is locked against stop screws 38 and 43 during v the return of the pendulum to neutral position.

since otherwise flexing might be permitted in the weaker spring 3|, thus returning the pendulum too slowly and producing an elongation of the last dot transmitted.

To make a dash or a series of dashes the padfree to flex under this movement of the pendulum, though during this portion of the pendulum movement most of the flexing occurs in the spring 3|. During this leftward swing of the pendulum, it moves from the neutral position represented by the dot and dash line 8| to the full line position shown in Fig. 10, the angularity of this movement being about three times that shown in Fig. 8 which occurs during the production of dots. The pendulum then swings back, flexing the spring 3| back to the neutral position as shown in Fig.11 in which the adjusting screws 38 and 43 are both in contact with the block 32. However, the pendulum continues its movement into the position shown in Fig. 12 to open the contact 55,

this movement from the neutral position to the end of the swing being accomplished by flexing of the spring only, which serves to determine the time during which the contacts are open between dashes. Thus it will beseen that during both the making of dots and the making of dashes the period during which the contacts are open is determined by the flexing of the stiffer spring 35 so that a uniform space between signals is produced regardless of whether dots or dashes are being made. By causing the pendulum to move leftward through fiexure of the spring 3| during the making of dashes, the pendulum is caused to ill pin 51 swing the frame to the left until the frame strikes the stop screw 11. bringing the parts approximately to the position shown in Fig. 11 and at about this time the contacts are closed. This moves the end of block 32 away from the end .of the actuating lever and the pendulum continues its swing toward the left. both the flexible spring 3| and the stiffer spring 35 being consume approximately three times the period of time in its forward swing so as to produce the longer dash signal.

The springs 3| and 35 are arranged side by side in parallelism with the block interposed therebetween for the purpose of keeping the efiective length of the pendulum nearly constant when making both dots and dashes when either or both springs are in operation so as to give an approximately constant ratio between the dash interval on the one hand and the dot and space intervals.

In this instance the spring 35 is approximately twice as thick and eight times as stiff as the spring 3| and, therefore, when the pendulum is swinging with just spring 35 flexing, the effective spring tension is approximately nine times the eifective tension when both springs 35 and 3| are in operation, it being understood that the terms stiff and flexible as used in this application are intended to indicate relative flexibility only. Since the frequency of the pendulum oscillation varies directlyas the square root of the spring tension, the pendulum will oscillate with three times the period with spring 35 in operation as when both springs 35 and 3| are in operation. If the control paddle is held in the dash position, the pendulum continues to oscillate producing a series of dashes until the energy of the pendulum is exhausted or the paddle is released. When the paddle is released, coil spring 1.5 causes the actuating lever 65 to pivot on its center and make contact at its ends with the block 32, and thus swing the pendulum toward the neutral position. It will be seen that if a dash is in the making when the control paddle is released the dash is circuit; bringing the parts back to the rest position.-

InFigs. 3, .4 and 5 I have shown a modified form of construction in which the function of the screw 12 and spring 15 is performed by an alternative construction. In this form the spring 3| -is held in position by a screw which also has aspacing collar 85, the screw having a spacing shoulder 86 thereon adapted to abut against the collarto provide predetermined clearance between the head and the collar. Positioned on the screw is a latch bar 81 arranged to slide on the screw, the bar having a beveled end 88 arranged to engage with a beveled end 89 on the block 32 so that when engaged as shown in Fig. 3, the latch bar holds the block against the ends of the adjusting screws 43 and 33 so as to prevent displacement; of the block when the paddle is moved to a position to make dots. Positioned in'theiactuating lever 65 is a screw 9| having a pointed end adapted for reception in an opening 92 in the latch bar so that when the paddle is moved upward facing Fig. 3 into the dash position, the end of the screw 9| is forced against the end of the opening 92 causing the latch bar to move to the left facing Fig. 3 so as to release the block 32. The frame is provided with fingers 93 to resist the pressure'of the screw 9| when the paddle is thus moved. A spring 94 bearing on'an arm 90 on a bracket which also carries the fingers 93 acts against the end of the latch bar 81 causing the latch bar to move forward as to the right facing Fig. 3 when the paddle is returned to the neutral or dot position. With this exception the construction and operation of the form shown in Figs. 3, 4 and 5 is the same as that heretofore described.

' An important feature of the invention consists swings free except for the tension of the springs,

3| and 35, and for this reason the contact leaf does not affect the length of the dash interval. Furthermore, the contact leaf exerts force upon the pendulum only during that portion of the pendulum swing from the dotted line position of Fig. 8 to the position shown in Fig. 9, and the pressure of this spring constitutes a relatively small proportion of the total spring pressure acting upon the pendulum during this portion of its movement. Therefore, the correct ratio between the lengths of the dots, spaces and dashes is not greatly affected by changes in the pressure of the' contact leaf 54.

Another important feature of the invention is thevibration damper acting on the contact leaf 54. In operation, as the spring leaf 54 flexes it slides through the clamping jaws 63 and 64 of the damper and the friction caused by this movement prevents free vibration of the leaf and minimizes sputtering and other keying faults commonly caused by vibration of the contact spring. For example, as the contact 55 strikes the contact 56 during the formation of a signal it tends to bound like a hammer striking an anvil. The damper reduces this bounding to a minimum.

Attention is also directed to the novel manner in which the pendulum is supported and controlled whereby both dots and dashes are produced by operation of the same paddle, the-same pendulum and the same set of contacts.

I claim: v 1. The combination in a telegraph key of contacts arranged to be opened and closed to produce a signal, a pendulum, means for supporting said pendulum in a neutral rest position when unrestrained, means for initiating movement of said pendulum on said supporting means in one di-' rection from a neutral point with a substantially fixed period to open said contacts and in the opposite direction from said neutral point with either of two periods corresponding to the closed contact times required for dot and dash signals, and manually operable means for selecting either of said two periods to produce dot or dash signals at will.

2. The combination in a telegraph key of a pair of contacts arranged to be opened and closed to produce a telegraph signal, a pendulum having means for opening said contacts during a fixed portion of its swing, spring means acting on said pendulum 'to cause the same to swing to opposite sides from a neutral position, said spring means having a stiff portion for effecting movement on opposite sides of said neutral position through equal periods, and a more flexible portion for effecting movement of said pendulum through a slower period, means for confining the action of said flexible spring on said pendulum through movement of the pendulum on one side of said neutral position, and manually operable means for initiating movement of the pendulum and for controlling said confining means to effect movement of the pendulum in one direction from said neutral position under the action of said stiff spring on said pendulum, a pair of contacts positioned to be opened by said contact operating means in response to movement of the pendulum from the neutral position to one of said opposite positions to produce the interval between telegraph signals, the interval measured by movement of the pendulum from said neutral to the other of said opposite positions measuring the interval for a dot signal, a second and weaker spring operative on said pendulum on one side of said neutral position to effect a slower period of pendulum movement and thereby produce a dash signal, and manually operable means for rendering one or the other of said springs effective on said pendulum on said one side of the neutral position to selectively produce either a dot or a dash signal.

4. The combination in a telegraph key of a pendulum comprising a substantially rigid bar,

a rigid block, a stiff leaf spring connecting said bar and said block, a support for said pendulum and a second more flexible leaf spring connecting said block to said support to support the pendulum for oscillation by flexing of said spring, a

pair of contacts positioned to be opened by niove-' tacts" for uniform periods, and manually operable means for engaging or releasing said block for movement to the other side of said neutral position againstthe tension of one or the other of said spring to cause said bar to oscillate at periods to produce either dot or dash signals by the closing of said contacts,

.5. The combination in a telegraph key of a pendulum comprising a substantially rigid bar, contacts positioned to be opened by movement of i said bar to one side of a neutral position and tatable support means attached to said flexible spring for supporting the pendulum, springs and block, stop members acting on opposite sides of said block to prevent movement thereof to said g one side of the neutral position, stop means disposed adjacent said rotatable support means, and

manually operable means for rotating said support means into contact with said stop means to impart oscillation to said pendulum and thereby produce dash signals.

6. The combination in a telegraph key of a pendulum comprising a substantially rigid bar, contacts positionedto be opened by movement of said bar to one side of a neutral position and clsoed by movement thereof to the other side of said neutral position, a relatively stiff spring attached to one end of said bar and disposed substantially in parallelism therewith, a rigid block attached to the free end of said spring and disposed alongside said spring in substantial parallelism therewith, a second more flexible spring attached to said block in a plane intermediate the ends of said stiif spring and extending in parallelism with said block and said stiff spring, means attached to said flexible spring for supporting the pendulum, springs and block, stop members acting on opposite sides of said block to prevent movement thereof to said one side of the neutral position, manually operable means operative on said block in one position to confine the same between said stops and to initiate movement of said pendulum to opposite sides of the neutral position under flexing of said stiff spring to produce dot signals, and ma second position to release said block for'movement of said pendulum to said other side ofthe neutral position by flexing of said more flexible spring to produce dash signals.

7. The combination in a telegraph key of 'a frame, means for supporting said frame for rotation about a transverse axis intermediate its ends, frame stops disposed adjacent opposite-sides of said frame between said supporting means and one end thereof, a flexible leaf spring carried on said frame and projecting longitudinally there-- on, a rigid spring block attached to said spring, a stiff spring attached to said block, a rigid pendulum bar carried on said stiff spring, pendulum stops on said frame adjacent said sides of said block spaced longitudinally thereof to hold said block and springs in a neutral position when the block engages said stops, contacts positioned to be opened by said bar upon movement thereof to one side of a neutral rest position, and a manually operable actuating lever pivoted on said frame intermediate said transverse axis and said pendulum stops on an axis parallel to said transverse axis for holding said block against said pendulum stops and moving said frame against one of said frame stops upon actuation in one direction to impart swinging movement to said bar and flexure to said stiff spring nd thereby alternately open and close"said contacts for substantially equal periods to produce dot signals, and for releasing said block from said pendulum stops and moving said frame against one of said frame stops upon actuation in the opposite direction to impart swinging movement to said bar and flexure to both of said springs and thereby alternately open and close said contacts for different periods to produce dash signals.

8. The combination in a telegraph key of a frame, means for supporting said frame for rotation about a transverse axis intermediate its ends, frame stops disposed-adjacent opposite sides of saidframe between said supporting means and one end thereof, a flexible leaf spring carried on said frame and projecting longitudinally thereon, a rigid block attached to said spring, a stiff spring attached to said block, a rigid pendulum bar carried on said stiff spring, pendulum stops on said frame adjacent opposite sides of said block spaced longitudinally thereof to hold said block and springs in a neutral position when the block engages said stops, contacts positioned to be opened by said bar upon movement thereof to one side of a neutral rest position, and a manually operable actuating lever pivoted intermediate its ends on said frame on an axis intermediate said transverse axis and-said pendulum stops and on an axis parallel to said transverse axis, said lever having an end projecting beyond one end of said frame for a handle and an opposite end adjacent said block and one of said frame stops, said opposite end moving against said block'to hold the same against said pendulum stops and moving said frame to rotate said frame into contact with the other of said frame stops. upon actuation of said lever in one direction to impart swinging movement to said bar and flexure to said stiff spring only and thereby alternately open and close said contacts for substantially equal periods to produce dot signals and moving away from said block and into contact with the first mentioned frame stop'to release said block from said pendulum stops and to rotate said frame against the second mentioned frame stop upon actuation in the opposite direc on to impart swinging movement to said bar and flexure to both of said springs to alternately open and close said contacts for different periods to produce dash signals.

9. Th combination in a. telegraph key of a frame, means for supporting said frame for rotation about a transverse axis intermediate its ends, frame stops disposed adjacent opposite side of said frame between said supporting means and one end thereof, a flexible leaf spring carried on said frame and projecting longitudinally thereon, a rigid block attached to said spring, a stiff pring attached to said block, a rigid pen dulum bar carried on said stiff spring, pendulum stops on said fram adjacent opposite sides of said block spaced longitudinally thereof to hold said block and springs in a neutral position when the block engages said stops, contacts positioned to be opened by said bar upon movement thereof to oneside of a neutral rest position, a manually operable actuating lever pivoted intermediate its ends on said frame on an axis intermediate said transverse axis and said pendulum stops and on an axis parallel to said transverse axis, said lever having an end projecting beyond one end of said frame for a handle and an opposite end adjacent said block and one of said frame stops, said opposite end moving against said block to hold the same against said pendulum stops and moving said frame to rotate said frame into contact with the other of said frame stops upon actuation of said lever in one direction to impart swinging movement to said bar and flexure to said stiff spring only and thereby alternately open and close said contacts for substantially equal periods to produce dot signals and moving away from said block and into contact with the first mentioned frame stop to release said block from said pendulum stops and to rotate said frame against the second mentioned frame stop upon actuation in the opposite direction to impart swinging movement to said bar and fiexure to both of said springs to alternately open and close said contacts for different periods to produce dash signals, spring means for maintaining said opposite end of the actuation lever against the first mentioned stop in the rest position of the parts, and spring means for maintaining said opposite end aginst said block.

10. The combination in a telegraph key of a frame, means for supporting aid frame for rotation about a transverse axis intermediate its ends, frame stops disposed adjacent opposite sides of said frame between said supporting means and one end thereof, a flexible leaf spring carried on said frame and projecting longitudinally thereon, a rigid block attached to said spring, a stiff spring attached to said block, a rigid pendulum barv carried on said stifi spring, pendulum stops on said frame adjacent opposite sides of said block spaced longitudinally thereof to hold said block and springs in a neutral position when the block engages said stops, contacts positioned to be opened by said bar upon movement thereof to one side of a neutral rest position, a manually operable actuating lever pivoted intermediate its ends on said frame on an axis intermediate said transverse axis and said pendulum stops and on an axis parallel to said transverse axis, said lever having an end projecting beyond one end of said frame for a handle and an opposite end adjacent said block and one of said frame stops, said opposite end moving against said block to hold the same against said pendulum stops and moving said frame to rotate said frame into contact with the other of said frame stops upon actuation of Said lever in one direction to impart swinging movement to said bar and fiexure to said stiff spring only and thereby alternately open and close said contacts for substantially equal periods to produce dot signals and moving away from said block and into contact with the first mentioned frame stop to release said block from said pendulum stops and to rotate said frame against the second mentioned frame stop upon actuation in the opposite direction to impart swinging movement to said bar and flexure to both of said springs to alternately open and close said contacts for different periods to produce dash signals, spring means acting between said frame and said actuation lever for maintaining said opposite end of the actuation lever against said block, and spring means acting against said frame for maintaining said opposite end of the actuation lever against the first mentioned frame stop in the rest position of the parts.

11. The combination in a telegraph key of a frame, means for supporting said frame for rotation about a transverse axis intermediate its ends, frame stops disposed adjacent opposite sides of said frame between said supporting means and one end thereof, a flexible leaf spring carried on said frame and projecting longitudinally thereon, a rigid block attached to said spring, a stiff spring attached to said block, a

rigid pendulum bar carried on said stiff spring, pendulum stops on said frame adjacent opposite sides of said block spaced longitudinally thereof to holdsaid block and springs in a neutral position when the block engages said stops, contacts positioned to be opened by said bar upon movement thereof to one side of a neutral rest position, a manually operable actuating lever pivoted intermediate its ends on said frame on an axis intermediate said transverse axis and said pendulum stops and on an axis parallel to said transverse axis, said lever having an end projecting beyond one end of said frame for a handle and an opposite end adjacent said block and one of said frame stops, said opposite end moving against said block to hold the same against said pendulum stops and movingsaid frame to rotate said frame into contact with the other of said frame stops upon actuation of said lever in one direction to impart swinging movement to said bar and fiexure to said stiff spring only and thereby alternately open and close said contacts for substantially equal periods to produce dot signals and moving away from said block and into contact with the first; mentioned frame stop to release said block from said pendulum stops and to rotate said frame against the second mentioned frame stop upon actuation in the opposite direction to impart swinging movement to said bar and flexure to both of said springs to alternately open and close said contacts for different periods to produce dash signals, a latch projection on said block, latch means engaging said latch projection for holding said block against said pendulum stops, and means for releasing said latch projection in response to movement'of said latch lever in said opposite direction.

12. The combination in a telegraph key of a frame, means for supporting said frame for rotation about a transverse axis intermediate its ends, frame stops disposed adjacent opposite sides of said frame between said supporting means and one end thereof, a flexible leaf spring carried on said frame and projecting longitudinally thereon, a rigid block attached to said spring, a stiff spring attached to said block, a rigid pendulum bar carried on said stiff spring, pendulum stops on said frame adjacent opposite sides of said block spaced longitudinally thereof to hold said block and springs in a neutral position when the block engages said stops, contacts positioned to be opened by said bar upon movement thereof to one side of a neutral rest position, a manually operable actuating lever pivoted intermediate its ends on said frame on an axis intermediate said transverse axis and said pendulum stops and on an axis parallel to said transverse axis, said lever having an end projecting beyond one end of said frame for a handle and an opposite end adjacent said block and one of said frame stops, said opposite end moving against said block to hold the same against said pendulum stops and moving said frame to rotate said frame into contact with the other of said frame stops 'upon actuation of said lever in one direction to impart swinging movement to said bar and fiexure to said stiff spring only and thereby alternately open and close said contacts for substantially equal periods to produce dot signals and moving away from said block and into contact with the first mentioned frame stop to release said block from said pendulum stops and to rotate said frame against the second mentioned frame stop upon actuation in the opposite direction to impart swinging movement to said bar and fiexure to both of said springs to alternately open and close said contacts for different periods to produce dash signals, a latch projection on said block, a latch bar slidably disposed in said frame, spring means for engaging said latch bar with said latch projection to hold said block against said pendulum stops, and means on said actuatingv lever for disengaging said latch bar upon movement of the lever in said opposite direction.

13. The combination in a telegraph key of a frame, a vertical spindle intermediate the ends of said frame for supporting the same for rotation about said spindle, frame stops disposed on opposite sides of said frame between said spindle and one end of said frame for limiting the rotation of said frame, a rigid pendulum bar, a fiexible leaf spring attached at one end on said frame adjacent said one end and projecting longitudinally thereof, a rigid block attached at one end to the opposite end of said spring and disposed beside and in parallelism therewith, a stiff spring having one end attached to said pendulum bar to support the same for oscillating movement on opposite sides of a neutral unstressed position of said springs and the other end attached to the opposite end of said block and disposed beside and in parallelism therewith and with said flexible spring to provide substantially equal effective pendulum lengths when said pendulum oscillates on either of said springs, pendulum stops on said frame adjacent opposite sides of said block and spaced longitudinally thereof to hold said block and said springs in coplanar position when at rest, contacts positioned to be opened by said bar upon movement thereof to one side of said neutral rest position through fiexure of said stiff spring, and a manually operable actuating lever pivoted on said frame intermediate, said transverse axis and said pendulum stops on an axis parallel to said transverse axis movable in one direction for holding said block against said pendulum stops and for moving said frame against one of said frame stops to impart swinging movement to said pendulum bar and fiexure to said stiff spring and thereby alternately open and close said contacts for substantially equal periods to produce dot signals and movable in the opposite direction to release said block from said pendulum stops and move said frame against said one of said stops to impart swinging movement to said bar and flexure to said flexible spring during oscillatory movement of said bar to the opposite side of said neutral position and fiexure of said stiff spring upon movement of said bar to the first mentioned side of said'neutral position to alternately open and close aid contact for different periods and thereby produce dash signals.

14. The combination in a telegraph key of an oscillatable pendulum, a fixed contact and a mobile contact adapted to be closed toproduce a signal, a flexible leaf spring mounted in a fixed position carrying said mobile contact and biased to a closed position, means on said pendulum insulated from said contacts operativeon said spring to open said contacts through a preselected portion of the pendulum oscillation to produce the interval between signals, andmeans acting on said pendulum to bring the same to a-point of rest in a position where the last mentioned means acts on said spring to maintain said contacts open.

15. The combination in a telegraph key of a base, an oscillatable pendulum for producing dot and dash signals, a single set of contacts adapted to be opened and closed to produce dot and dash signals including a stationary contact fixedly attached to said base and insulated therefrom, a movable contact, and a leaf spring carrying said movable contact fixedly attached to the base and insulated therefrom stressed in a direction to close said contacts, means on said pendulum insulated from said contacts operative on said leaf spring to open said movable contact against the tension of said spring through a pre-selected portion of each pendulum oscillation to produce the interval between signals, and spring mean to bring said pendulum to a point of rest in a position in which the last mentioned means actsto hold said contacts open.

16. The combination in a telegraph key of a base, an oscillatable pendulum, contacts adapted to be closed to produce a signal including a stationary contact fixedly attached to said base and insulated therefrom, a movable contact, and a leaf spring carrying said movable contact fixedly attached to the base and insulated therefrom stressed to normally close said contacts, means on said pendulum insulated from said-contacts operative on said leaf spring to open said movable contact against the tension of said spring through a pre-selected portion of'each pendulum oscillation to produce the interval between signals, and a vibration damper comprising a friction element acting on said spring intermediate its ends, and means for supporting said friction element to slide on said spring with fiexing of the spring to impart a frictional drag to the flexing thereof.

17. The combination in a telegraph key of a base, an oscillatable pendulum, contacts adapted to be closed to produce a signal including a stationary contact fixedly attached to said base and insulated therefrom, a movable contact, and a leaf spring carrying said movable contact fixedly attached to the base and insulated therefrom stressed to normally close said contacts, means on said pendulum insulated from said contacts operative on said leaf spring to open said movable contact against the tension of said spring through a pro-selected portion of each pendulum oscillation to produce the interval between signals, and a vibration damper comprising frictional pads engaging opposite sides of said spring and a flexible leaf spring arranged in approximate parallelism with the contact spring for supporting said pads for frictional sliding movement on said contact spring with flexing thereof to impart a frictional drag to the flexing of the contact spring and thereby reduce rebound at the contacts.

18. The combination in a telegraph key of an oscillatable pendulum, a supporting frame rotatable about a fixed axis, a relatively stiff and a relatively weak spring disposed between. said frame and said pendulum, said stiff spring being disposed adjacent the pendulum and said flexible spring being disposed adjacent said frame, a frame stop for limiting the rotation of said frame,

means for rotating said frame against said stop to impart oscillation to said pendulum by flexing said springs, pendulum stop means for preventing fiexure of said flexible spring to one side of a neutral unstressed position of said springs, and

contact means positioned to be actuated by said pendulum upon movement thereof to said one side of said unstressed position through flexure of said stiff spring only.

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