ALLEN in detail.     On another page, we've given the historical details, such as are known, about the Allen.  Here, we'll take a detailed look at the machine with a detailed description and some expert opinions.  We're using our Allen, serial number 4341 for this project.  Below, we see the Allen between a post-1920 Corona 3 (left) and a Portex No. 5 (right) for a size comparison.  Note that all three are three-bank, double-shift machines employing carriage shift..
DESCRIPTION.  The Allen, a product of the Allen Typewriter Manufacturing Company, Allentown Pennsylvania, is a three-bank double-shift front strike portable manufactured as simply and inexpensively as is possible.  The machine has 29 keys, typing 87 characters; a shift lock is provided.  Capital shift keys are on both sides of the keyboard, and the figure shift key is on the left side only.  Shifting is by carriage motion, with operation of the CAP keys moving the carriage downward, and the FIG key moving it upward from the center or neutral position.  The machine is equipped with a two-color ribbon selector, manual ribbon reverse, and is also equipped with a back-spacer.  Carriage details include squeeze-type line space mechanism, located on the right side of the carriage (three degrees of line-space are available) in addition to a paper bail (without rollers) and paper release.  Margin release is accomplished by a lever on the left rear of the carriage; carriage release lever is located on the left side only, and when operated also releases the margins so that the typist can move the carriage to any point desired including bypassing the margin stops.
The machine is equipped with a ratchet release for the platen (whose operating lever is on the right, rear of the carriage) allowing free-wheeling of the platen for form work; line-spacing is retained.  The machine does not incorporate a conventional right-margin warning, but rather a single-stop device whose operation is novel and must be explained.  Upon reaching the right-side margin, the keyboard will lock for one stroke only; this serves as the typist's only warning.  After the one abortive key stroke, the mechanism unlocks and the keys and carriage are again freed.

The machine is manufactured as simply and economically as possible, including the use of light-weight, stamped body sides, rear and top and is lighter than might appear.  A sturdy carrying case is provided.  The typing action is firm, with a strong impact of the type-bars, and the machine makes good, dark impression and would likely be a decent manifolder.
DETAILS OF OPERATION.  The FIG and CAP shift keys may be locked in "shifted" position by depression of the silver rod seen protruding through the front, left of the front frame rail.  They are released by sharply tapping the same key; the shift lock rod pops back out, forward, releasing the carriage to the center or neutral position.  Back-spacing is accomplished by depression of the device seen below the space bar, in the center, also silver.  Both devices, when operated, depress straight back toward the rear of the machine.
A view of the right side of the Allen shows the ribbon color selector just below the carriage; colored targets either side of the print alignment fork support indicate the color selected.  Lower on the right side is the manual ribbon reverse knob, pushed in or pulled out to select direction of ribbon travel.
PRESENT DAY ANALYSIS.    Above, I've given my best attempt at a Carl Mares - like review of the details of the Allen, including its operative features and points.  However, this is not the complete picture; as it would turn out, the Allen was made in small numbers, with even smaller numbers surviving, because quite frankly it is one of the worst typewriters we've ever operated here.

The machine's worst point is the operation of the shift; the carriage is bouncy when returning to center, from shift positions, since there is no attempt made to arrest motion upon return to center.  This would severely hinder speed and rhythm since the typist must wait shortly after releasing the shift key before striking the next character; if this consideration were not made, the next character would be either high or low compared to the print line typed previously.  The typing action is abrupt, with the type-bars hitting the platen with a solid feel.  While the machine does type solidly, the feel is almost brutally primitive and is among the most primitive ever tested here, if not THE most.  The right-side stop feature is novel, and perhaps workable if familiar; the Emerson and Woodstock-like feature of ensuring that the carriage release allows the typist to move the carriage past the margin stops is also a feature liked here (and it should be noted that Richard Uhlig designed the Emerson, and the design feature was simply retained in the Woodstock.)  Those two points cannot save the machine, though; further problems are lack of reliable paper feed due to the primitive carriage construction.  The paper release is also primitive, and would seem to be designed badly enough that, after time, there is the distinct possibility that it would not lock in the release position.  Even worse than that are the two front-mounted controls - the shift lock, and the back-spacer.  The shift lock is inconvenient, even if positive in action; the back-spacer is perhaps the most awkward ever tested.  The back-spacer is in the wrong place, is balky in operation, and certainly appears applied almost as an afterthought. 
Now, a few observations from others:

David B. Davis:  "It's obvious that it was designed to be as cheap as possible, but it's an interesting design.  It IS attractive - it's a nice looking machine, and I do like the chromed ribbon spool supports."

Craig Burnham, owner Your Typewriter & Computer:  "It was cheaply made, all right, probably not real reliable.  But it is simple - you add another two or three hundred parts to anything, and you just can't get to ANYTHING that breaks."  Craig noted the totally open main spring - "Usually you have to take a bunch of stuff apart to get at that when it breaks, and on this one it's wide open."  I asked him if he'd have liked to sell, and offer warranty coverage, on such a machine -- the answer was "No."  Craig was very polite in indicating that the machine was "very interesting" in a sort of "why did they even make this thing" kind of way.  He noted how bad the shift design was, and wondered how long it would be before the upward motion forced the side plate - all that's stopping it - out of shape.  He was unimpressed with the back-space as well.
David A. Davis, my brother, noted the design and method of assembly for the Allen.  Sides, rear, top and front rail are all stampings - and the sides are spot-welded to the rear panel and front frame.  In this rear view, the weld spots -- probably electric or resistance welds -- are seen as dots or dimples on the scalloped sections of the side plates that are bent 90 degrees and joined to the rear plate.  The front rail is jointed and welded the same way.  The top plate is held in place by the side plates. 

Dave also noted that both the carriage rail, or frame, is very simply a piece of machined bar stock, and so is the frame on which the carriage itself is built.  Carriage ends are very simple stampings; the cross-member on which the segment is mounted is also a stamping.
I myself noted (among all the other bad features) the "thwack" of the type bars against the platen, surely one of the most distinct of any machine of this class I've tested.  The type-bar mechanism is exceedingly simple, and while some might consider the necessity of this impact due to the quality of ribbons of the day, I'd think it's too much.  Moreover, the return speed of the type bars is slow and this, coupled with the need to wait until the carriage comes to rest after shifting, makes this one SLOW typewriter.  Combine that with the other retrograde features, and let me tell you- you got one BAD typewriter.

Of course, we must stop and examine the machine in the context of the day.  Could it get print on paper?  Yes.  Can it type clearly in a straight line, even if slowly?   Yes.  Would it be easy enough to fix, when something did break or work out of alignment?  Probably.  You do get what you pay for, and as a cut-rate workable portable machine for someone who only occasionally had to use it, or else was not interested in speed, it would have worked well enough for a while.  But, in the early 1920's when we think the machine was made, there were very much better portables around, with much better post-sale support.  Only if this machine were exceedingly inexpensive would it have been worth a look, and once tested might well have been ignored.  It does appear that, once again, that "most knowledgeable of all the failed typewriter inventors" Richard Uhlig produced a machine with operative and design qualities as notorious as his Emerson.