Single shaft sheet advancement mechanism

A copysheet incremental feeder apparatus (10) comprising a drive unit (11) operatively connected to a rotor actuating unit (12) which drives a "floating" roller unit (13) rotatably disposed in a roller housing unit (14), whereby the floating roller element (27) produces a positive friction drive on the copysheet (100), regardless of the vertical disposition of the roller unit (13) within the housing (14).

TECHNICAL FIELD 
This invention relates generally to the field of sheet advancement 
mechanisms, and more specifically to a copyholder sheet advancement 
mechanism for use by keyboard operators. 
BACKGROUND ART 
This invention was the subject matter of Patent Office Disclosure Document 
No. 124,653 filed Mar. 21, 1984. 
Numerous attempts have been made in the past to develop a desk top or 
typewriter attached copyholder sheet advancement mechanism that is simple, 
efficient, quiet, compact and reliable. 
Most of the prior art mechanisms that have been developed share common 
structural features such as a ratcher or pawl advancement mechanism and a 
plurality of drive rollers in the form of a feed roller and a pressure 
roller used to frictionally engage and incrementally advance a sheet of 
paper placed in the mechanism. 
In addition, the prior art mechanisms range from the extremely simple 
structures to the extremely complex structures, and they may further be 
manually or automatically controlled and driven either electrically, 
mechanically, or pneumatically. 
Some representative examples of the myriad aforementioned prior art 
mechanisms my be seen by reference to the following U.S. Pat. Nos.: 
2,949,886; 1,730,445; 3,030,923; 2,006,609; 2,273,388; 2,633,828; and 
3,003,467. A quick review of these listed patents will make it abundantly 
clear how different are the end products of the various approaches to this 
problem. 
It should also be apparent that this wealth of prior art is directly 
attributable to the fact that a perfect or near perfect solution to the 
copyholder feeding problems has up until the present time been lacking. 
DISCLOSURE OF THE INVENTION 
Most, if not all, of the problems, inferred above, are substantially 
resolved by the provisions of the instant invention. The instant invention 
comprises in general a remote drive unit, a rotor actuating unit, a roller 
unit, and a roller housing unit. 
The drive unit per se is not considered an integral part of this invention 
and may comprise either an electrical, mechanical, or pneumatic drive 
mechanism or a drive mechanism that combines features from the various 
drives. For the purposes of this invention, any suitable drive mechanism 
will suffice, as long as it is capable of transmitting force to a remote 
location. 
The rotor actuating unit is operatively connected to the drive mechanism 
and comprises a pawl and ratchet arrangement, which incrementally advances 
the roller unit in a well recognized fashion. 
The roller unit comprises a free floating roller assembly wherein the 
roller element is vertically displaceable with respect to the roller 
housing member so that the full weight of the roller element is 
transmitted to the sheet of paper. 
The roller housing unit comprises a clear acrylic housing member having an 
arcuate interior and provisions for receiving the roller unit, and the 
actuating unit. In addition the housing member is further provided with a 
lateral paper guide element that insures the proper orientation of the 
sheet, as it is transported through the combined apparatus. 
The roller housing unit also comprises, mounting means in the form of 
variously configured end plates that will allow the roller housing unit to 
be mounted directly above an alphanumeric keyboard, such as is found on a 
typewriter, telex machine, typeset machine, computer or the like. 
With the apparatus mounted above the keyboard and the remote drive unit 
operatively connected to the rotor actuating unit, the apparatus is ready 
for use; the operator simply feeds the copysheet downwardly into the 
roller housing, and the longitudinal stiffness of the sheet will lift the 
free floating roller out of engagement with the interior wall of the 
roller housing to frictionally engage the copysheet between the roller and 
the housing wall. The drive unit is then selectively actuated to cause the 
incremental advance of the copysheet through the apparatus at a speed 
determined by the requirements of the operator. 
It should further be appreciated that the ratchet and pawl stepping 
assembly produces a positive paper drive in one direction; and when the 
ratchet is released at the top of the actuating stroke, returns to its 
starting position for the next incremental advance of the copysheet.

BEST MODE FOR CARRYING OUT THE INVENTION 
Referring now to the drawings, and in particular to FIG. 1, the apparatus 
may be seen as depicted generally by the numeral (10). The apparatus (10) 
includes generally a remote drive unit (11), a rotor actuating unit (12), 
a roller unit (13) and a roller housing unit (14). Each of these units 
will now be described in seriatim fashion. 
As mentioned earlier in the specification, this invention may be practiced 
using a direct drive unit, or any one of a variety of remote drive units 
(11), and the invention should not be limited to the particular drive unit 
(11) illustrated in the drawings. It should be noted, however, that the 
drive unit, illustrated in the drawings contains unique structural 
features, that represent an advancement over the prior art drive units. 
As can be seen by reference to FIG. 6, the drive unit (11) of the preferred 
embodiment comprises in general a support housing (15) having an axle 
member (16) which rotatably supports a drive element (17). The drive 
element (17) further comprises a cylindrical member (18) having a drive 
bar (19) projecting radially outwardly therefrom, in a generally 
horizontal disposition. 
The drive unit (11) is operatively connected to the rotor actuator unit 
(12) via an elongated filament (20) that is stretched between the 
respective units. The filament (20) in the preferred embodiment comprises 
a length of monofilament or the like, wherein the force applied to the 
drive bar (19) is transmitted via the filament (20) to the rotor actuator 
unit (12). 
As can best be seen by reference to FIGS. 5 and 6, the rotator actuating 
unit (12) comprises in general an elongated actuator member (21) pivotally 
secured proximate its mid-point to the roller housing unit (14). The 
outboard end (22) of the actuator member (21) is provided with a weighted 
element (23) to bias the outboard end (22) in a downward direction; and 
the inboard end (24) of the actuator member is provided with an actuator 
force receiving means (25). 
In the version of the preferred embodiment illustrated in FIG. 5, the 
actuator force receiving means (25) comprises an elongated bar (25') that 
is horizontally disposed across the roller housing unit (14); and in this 
instance the elongated bar (25') functions as the drive unit (11), 
inasmuch as the drive force is intended to be applied directly to the 
elongated bar (25') to rotate the actuator member (21) about the pivot 
(26) to the rotor actuating unit (12). 
The aforementioned force transmittal to the rotor actuating unit (12) is 
accomplished through a resilient drive means (80) whose purpose, function, 
and construction, will be explained in detail further on in the 
specification. 
The roller unit (13) comprises in general a roller member (27) having 
elongated axles (27') formed on its ends. The roller member (27) is 
rotatably disposed in the roller housing unit (14), and has a main body 
element (28) formed from a length of clear acrylic rod stock. In addition, 
the main body element (28) is further provided with a plurality of sleeve 
members (29) that act as the friction surface that will actually drive the 
copysheet through the apparatus (10). 
The roller housing unit (14) comprises two vertically upstanding end plate 
members (30) connected at their upper ends by a semi-circular acrylic 
trough element (32), which defines the lower portion of the paper path. 
The trough element (32) is further provided with an elongated paper guide 
element (33) disposed proximate to, but spaced from the inboard end of the 
trough element (32). As shown in FIGS. 4 and 5, the paper guide element 
(33) comprises an elongated acrylic rod member (34) which extends between 
the end plate members (30) and (31). 
As shown in FIG. 4, end plate member (31) is provided with an elongated 
slot (35) that is dimensioned to receive and support one of the roller 
axles (27'); and, as shown in FIG. 6, end plate member (30) is provided 
with a generally elliptical aperture (36) shown in phanton that is 
dimensioned to allow limited vertical translation of the other roller axle 
(27') therein. This arrangement provides a "floating" support system for 
the roller member (27) within the roller housing unit (14). In addition, 
each of the roller axles (27') are provided with knob elements (37) on 
their outboard ends, to provide manual rotation of the roller member (27) 
when desired. 
Turning now to FIG. 7, it can be seen that the rotor actuating unit (12), 
comprises a rotor assembly (50), and a pawl assembly (60) which are 
operatively connected to one another and to one of the roller axles (27') 
via a ratchet element (70) such as ratchet gear (71). 
The indexer assembly (40) comprises an axle element (41) rigidly secured to 
end plate member (30) and having an elongated aperture (42) that coincides 
with the generally eliptical aperture (36) in end plate member (30). The 
indexer assembly (40) also comprises an indexer member (43) rotatably 
disposed on the axle element (41) and provided with a stop element (44) 
and an indexer lever (45) is disposed generally perpendicular to the 
roller axle. (27'). 
The final component of the indexer assembly (40) comprises an indexing 
plate (46), disposed across the trough element (32) of the roller housing 
unit (14), and provided with a plurality of notches (47) that are 
dimensioned to receive the indexer lever (45), to vary the position of the 
stop element (44) within the roller housing unit (14). 
The rotor assembly (50) comprises a contoured rotor cam element (51), 
rotatably disposed on the roller axle (27') and provided with an elongated 
force transmitting element (52) projecting downwardly therefrom and 
operatively engaging the resilient drive means (80) mentioned supra. The 
contoured rotor cam element (51) having a generally flat edge (54) that is 
adapted to contact the stop element (44) on the indexer member (43) to 
limit the rotary motion of the cam element (51) on the roller axle (27'). 
The pawl assembly (60) comprises a toothed pawl element (61) pivotally 
secured to the upper portion (53) of the cam element (51) via a pivot 
element (62). The toothed pawl element (61) is adapted to operatively 
engage the ratchet element (70) which is rigidly attached to the roller 
axle (27'), to impart rotation to the roller member (27) in one direction 
only. When the toothed pawl element (61) moves in the counter-clockwise 
direction, as seen in FIG. 5, the roller member (27) has rotary movement 
imparted thereto. However, when the toothed pawl element (61) moves in the 
clockwise direction, no rotary movement is imparted to the roller member. 
Turning again to FIG. 7, the resilient drive means (80) comprises an 
elongated spring wire element (81) having one end (82) affixed to the 
actuator member (21) and having a loop (83) formed on its other end (84). 
The loop (83) of the resilient drive means (80) slidingly engages the 
force transmitting element (52) of the rotor assembly (50) to impart 
rotary motion thereto. 
It should be appreciated at this point that force exerted on the drive unit 
(11) will be transmitted through the rotor actuating unit (12) to impart 
rotary movement to the roller unit (13). In addition, the roller axis 
members (27') are suspended in a "floating" relationship with respect to 
the roller housing unit (14), to permit the vertical translation of the 
roller member (27) therein, to accommodate copysheets (100) of different 
thickness within the apparatus (10). 
It should also be appreciated at this juncture that the end plate members 
can be given different configurations that can be custom designed for 
attachment of the end plate members to any type of a device having an 
alpha numeris keyboard, and the present invention should not be limited to 
the particular structures illustrated and described herein. 
The operation of the apparatus (10) proceeds as follows: 
After the apparatus has been installed in its desired location on (or 
adjacent to) a keyboard, the keyboard operator takes the copy sheet in a 
reversed and inverted position, and forces the lower leading edge of the 
copysheet downwardly against the outboard edge of the roller member (27). 
The inherent longitudinal stiffness of the copysheet being of a sufficient 
magnitude to raise the "floating" roller upwardly out of engagement with 
the roller trough. Once the copy sheet has been interposed between the 
roller member and the roller trough, one or both of the axle knobs (37) 
may be rotated to feed the copysheet in a counter-clockwise direction. 
Since the leading edge of the copysheet is being engaged by the friction 
collars on the roller member that portion of the copysheet will retain the 
longitudinal stiffness to track the interior of the roller trough and 
thread itself between the paper guide and the forward end of the roller 
trough. When the copysheet has been advanced in this manner, to the point 
that the keyboard operator desires, the drive unit can be selectively 
actuated to incrementally advance the copysheet at whatever speed they 
require. 
Several features of this invention should be stressed at this point. The 
first of these is that virtually the entire apparatus can be fabricated 
with clear acrylic components, with the exception of the wire spring and 
the optional monofilament force transmitter. This type of construction 
produces an aesthetically pleasing arrangement that is virtually static 
free. 
However, the most important feature of this invention resides in the 
"floating" suspension of the roller member (27) within the roller housing 
(14); as well as the construction of drive unit (12), which has been 
specifically designed to insure a positive engagement of the toothed pawl 
element (61) with the ratchet element (71) regardless of the vertical 
displacement of the roller member (27) within the housing (14). 
Obviously, many modifications and variations of the present invention are 
possible in light of the above teachings. It is therefore to be understood 
that, within the scope of the appended claims, the invention may be 
practiced otherwise than as specifically described.