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10-4-2018 09:49:43  #1


Electric carriage return, Hermes Ambassador

I recently got a non-working Hermes Ambassador with the electric carriage return. It was seized due to surface rust but I have now got the type bars moving freely and am ready to look at the electrical side of things. 

There is an indicator bulb mounted on the front panel and this is rated 16volt 0.2amp. I am not sure if this is supposed to be on all the time the machine is plugged in or only when the carriage return is operated. The drawband is metal and the mainspring is mounted on an insulated block so there is no electrical contact between the drawband and the chassis.  When the carriage is mounted on the main body of the typewriter the mainspring spindle makes contact with an insulated terminal connected to the indicator bulb and isolated from the chassis. Neither side of the indicator bulb is connected to the earthed chassis.  The right hand end of the drawband has a nylon attachment to the carriage, ensuring its electrical isolation. There is a broken off end of wire on a solder tag at the right end of the drawband. Possibly this took power to, or provided switching information from something mounted on the carriage. The platen is 18" wide and there is the remains of what looks like some paper feed arrangement at the front of the platen.

At the back is a motor with a flexible drive to what I presume is some sort of clutch which pulls a drawband connected to a lever at the back of the carriage. If any of you have one of these machines I would be interested to find out if it works, how noisy it is and whether you know how the clutch is supposed to engage/ disengage from the band which operates the carriage return. 

It looks as if there is a capacitor and choke connected across the motor switch so I will check this works and replace if necessary before trying to run the motor.  There is an earthed mains lead which is a reassuring feature!
 

 

10-4-2018 16:55:37  #2


Re: Electric carriage return, Hermes Ambassador

I think the last time I saw one of these was about 35 years ago, so I am sorry but I cannot remember all the details of how it works.  I certainly don't remember any sort of indicator lamp.  As a general principle, the carriage return on any normal electric typewriter operates by a clutch winding up a drum (like a winch) which has the carriage return band attached.  The other end of the CR band usually pulls a lever (at the back of the carriage on the Hermes) which operates the linespace.  As the carriage reaches the left hand margin, a 'knock-off' mechanism operates, which releases the clutch.  On the electric carriage return manual model, I would say that the motor (and clutch if there is one) is only powered during the actual carriage return cycle.  Maybe the 'knock-off' mechanism is in fact a switch which cuts the power to the motor once the carriage has reached its destination.  Perhaps someone could elaborate.  Could you post some pictures ?

 

11-4-2018 11:21:30  #3


Re: Electric carriage return, Hermes Ambassador

https://i.imgur.com/xJNvzJx.jpg
https://i.imgur.com/1iQIxLd.jpg
https://i.imgur.com/LuF4qP0.jpg

     Thread Starter
 

11-4-2018 16:23:03  #4


Re: Electric carriage return, Hermes Ambassador

That's very interesting.  I would say that the long lever sticking up at the left of the first photo is the 'knock off', probably operated when the left margin is reached on the return cycle.  It is one of those things that you would have to examine from all angles, and maybe cycle through by turning the motor manually with the power off.  It does look as if there is a solid wire link disappearing towards the motor at centre bottom of the photo.  I wonder if this connects to a mains switch ?  The return cycle would be started by the typist pushing a large button (on the right of the keyboard), so it would be worth tracing what that connects to.  I would guess the sequence is - press button - motor activated and latched on, together with the carriage return clutch - carriage returns to left margin - knock-off operates - clutch unlatched - motor switched off.  Your typewriter is a very interesting rare survivor ! 

 

12-4-2018 05:18:58  #5


Re: Electric carriage return, Hermes Ambassador

Thanks for your helpful comments. This is definitely a machine that has seen better days but I would love to get it usable again. I will turn the motor by hand to get a better idea how everything works and to make sure some critical little lever isn't seized with rust. (The escapement mechanism was partly seized and it took a while to spot that a tiny bar with a small spring was only moving through part of its range - luckily I have a working one to compare it to).

I also thought I would disconnect the flexible drive from the carriage return clutch when the time comes to check the motor on/off controls work properly.

I have attached photos of the carriage which came with the remains of a paper feed attachment. The 18" ruler in the picture is just to show scale. The electric carriage return button is in the place normally occupied by the tabulator button. It is slightly worrying that they chose to label it with the electrocution hazard warning sign!https://i.imgur.com/MH0fkHt.jpg
https://i.imgur.com/5csnmLU.jpg
https://i.imgur.com/KFkEckT.jpg
https://i.imgur.com/UxdlOW3.jpg
https://i.imgur.com/yQ0cVEN.jpg

     Thread Starter
 

12-4-2018 05:37:37  #6


Re: Electric carriage return, Hermes Ambassador

https://i.imgur.com/9Pi761R.jpg
These cherry stones, eaten by a mouse, and some ears of corn fell out of the typewriter when I turned it upside down. It also came with several live harvester spiders.

     Thread Starter
 

12-4-2018 16:09:01  #7


Re: Electric carriage return, Hermes Ambassador

Ah-ha ! The carriage return button is on the left of the keyboard.  My memory was obviously playing tricks because I remembered it on the right !  I would guess that the typewriter was used for some sort of invoicing work because of the decimal tabulator and the special carriage.  Possibly the forms were on a continuous roll.  Good idea to physically disconnect the electric motor before powering up for the first time !  It looks as if the carriage return clutch (if there is one) is combined with a reduction gear in that aluminium housing at the back right hand side.  Keep us all posted how you get on.  This is all most interesting !  

 

13-4-2018 13:09:15  #8


Re: Electric carriage return, Hermes Ambassador

Everything on the main body of the typewriter appears to be working ok now (with the intermittent exception of the tabulator function). I checked the capacitor hadn't failed, made sure nothing live was shorted to earth, disconnected the flexible drive and plugged it in. The motor starts when the carriage return button is depressed and stops when the kick off lever is hit.
With it unplugged but flexible drive reconnected, turning the motor by hand winds back the carriage but it does not hit the lever which stops the motor. It is about 1mm off. Whether momentum is supposed to produce a bit of overshoot I don't know. The margin stops on the carriage are seized so I shall have to look at that next. I need to be convinced the motor will be stopped by the full return of the carriage to the left hand margin before trying it under motor power.

     Thread Starter
 

13-4-2018 16:29:17  #9


Re: Electric carriage return, Hermes Ambassador

Once the margins have been sorted out, I suggest you try it under power - with a finger on the mains on/off switch so that you can cut the power quickly if the knock-off doesn't operate !  I could guess that that 1mm will be taken up by the momentum, but if not, there is sure to be an adjustment of some sort if you trace the linkage through.

 

13-4-2018 20:54:37  #10


Re: Electric carriage return, Hermes Ambassador

I am following this thread with a lot of interest. You guys are way over my head, but it's a joy to read a discussion between two guys who know what they're doing, and working through some difficult repairs.

 

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