Apparatus and process for drop-feeding sheets to a typing or printing machine including separable paper clamping trays

In the present invention, a frame, mounted above the platen of a typewriter or a word processing machine, supports a drive roller in contact with the platen. This drive roller is also in contact with a tray-moving mechanism, supported above the drive roller. A plurality of trays carried in the frame are supported above the platen so as to hold sheets of paper or envelopes vertically between trays and in alignment with the sheet insert side of the platen. When the platen is turned backward, the drive roller actuates the tray-moving mechanism, causing a tray to move, separating it from the next adjacent tray and permitting a sheet of paper which had been placed therebetween to drop into position against the platen. Thus the sheets are fed automatically against the platen when the platen rotation is reversed.

BACKGROUND OF THE INVENTION 
Most typewriters and word processing machines are arranged for typing or 
printing one sheet of paper at a time. Some machines with pin-feed platens 
can take continuous strips of paper, but such devices are generally 
applied to computer and data processing machines of a more complicated 
construction. 
The disadvantage of the single-sheet feed construction (either for 
letter-size sheets or for envelopes) is that the operator must manually 
insert the sheet at the insert side of the platen of the typewriter or 
printing machine. 
In some word processing equipment, the rotation of the platen takes place 
automatically upon instructions from the word processing unit, and the 
sheet must be positioned on the printer ready to be advanced by the platen 
on instruction from the machine. 
In standard typing operations, the typist must insert the sheet against the 
platen, rotate the platen, and bring the sheet into typing position, but 
this action follows the manual insertion of the sheet against the platen 
by the typist. 
As has been stated previously, the pin-type platen advances edge-perforated 
sheets automatically into the typewriter, but the generally preferred 
method is to use individual sheet typing, which permits the utilization of 
differently printed letterheads, second sheets, copy paper, envelopes, 
labels, etc. 
To spend up the operation and efficiency of the typist, the drop-sheet 
feeder of the present invention is applicable. 
SUMMARY OF THE INVENTION 
The drop sheet feeder of the present invention includes a support (which is 
mounted on the frame of the typewriter or printer) and which supports the 
frame of the drop sheet feeder above the platen of the typewriter or 
printer. The feeder frame supports a plurality of trays disposed generally 
vertically above the platen in a manner which permits individual sheets of 
paper to be inserted between the trays and to be held in place between the 
trays, either by friction, interlocking fingers, or a fixed stop to keep 
the papers vertically positioned above the platen until one tray is 
separated from the others to permit the adjacent sheet to drop against the 
platen. A drive wheel mounted on the feeder frame rests against the platen 
of the typewriter or printer and also is in contact with a rotating 
tray-shifting member. When the platen is rotated backwardly, the drive 
wheel is caused to rotate, and this, in turn, actuates the tray shift 
member whereby the forward-most unshifted tray is moved away from the next 
adjacent tray in the stack. The sheet of paper (or envelope, etc.), which 
had been clamped between these two trays drops against the insert side of 
the platen, where it may be drawn into typing position to receive impact 
of the typewriter elements or printer element. The trays can be manually 
shifted so as to insert the desired sheets into the spaces between the 
trays, and thus the operator may place the various types of sheets, 
envelopes, etc., in proper sequence in the trays. 
The drop sheet feeder of the present invention does not require its own a 
motor or energy source, inasmuch as it receives its instruction and power 
directly from the platen, but if desired for independent operation, a 
separate motor may be utilized, and in this embodiment the drive for the 
feeder is not connected to the platen. 
Thus the drop sheet feeder of the present invention is uncomplicated and 
simple to construct, is relatively inexpensive, requires no independent 
power source, and can be applied to a great variety of typewriters and 
printers without modifying the typewriter or the printer. 
With the foregoing in mind, a principal object of the present invention is 
to provide a feeder mechanism for advancing individual sheets of paper 
against the platen of a typewriter or printer. 
Another object of the present invention is to provide an automatic sheet 
feeder which enables the operator to select different styles, sizes or 
forms of sheets to be fed seriatim and automatically to the platen of a 
typing or printing machine. 
Another object of the present invention is to provide a process for 
automatic printing or typing of separate sheets of different format. 
With the above and other objects in view, more information and a better 
understanding of the present invention may be achieved by reference to the 
following detailed description.

In FIG. 1, a bracket 20 is supported on the chassis 21 of a typewriter or 
printing machine 21-a as, for instance, by a strip of foam tape 22, which 
has adhesive on both sides and which can be positioned on the chassis of 
the typewriter 21-a to hold the bracket 20 in appropriate position to 
support the drop sheet feeder above the platen 23 of the printing machine 
21-a. The platen 23 is spaced from the chassis 21 and an insert area 24 is 
defined between the platen 23 and the chassis 21 to receive a sheet of 
paper 59 where it is grasped between the platen 23 and a friction roller 
25 so that the sheet 59 may be guided around the platen 23 and into 
operative juxtaposition to the typewriter keys or printer element. 
The bracket 20 has a slot 26 constructed and arranged to receive the 
support pins 27 of the feeder frame 28. 
Thus the entire feeder frame 28 with its wheels 29, 38, 41; gears 39-40; 
and trays 34, etc., may be removed from the typewriter or printer 21-a, 
merely by lifting frame 28 and the pins 27 out of the slot 26. 
The frame 28 supports a knurled wheel (or wheels) 29 on the shaft 30 in a 
position whereby the wheels 29 rest in operative contact with the platen 
23 when the pins 27 are in the slot 26. The weight of the drop feed 
mechanism causes the wheels 29 to be in close contact with the platen 23 
so that when the platen 23 rotates, the wheels 29 will also rotate. 
The knurled wheels 29 operate in conjunction with the wheel 31 (supported 
on the shaft 32) as will be seen more clearly when considering FIGS. 5, 12 
and 13. 
Fastened to the frame 28 is a brace or bracket 33 which extends vertically 
upwardly above the frame 28 and against which a plurality of sheet-guiding 
trays 34 are caused to rest, as against the portion 35 of the support 33. 
The bottom edges of the trays 34 are supported on a sloping surface 36 
which can be seen more clearly in FIGS. 3, 15 and 16. 
The tops of the trays 34 may be drawn forward by the machine operator in 
order to load the sheets of paper 59 therebetween (in the direction of the 
arrow 37 shown in FIG. 1). As will be described hereinafter, the bottom of 
the trays 34 also shift toward the left (FIG. 1) onto the surface 172 to 
drop the sheets 59, as required, against the platen 23 of the machine. To 
reset the trays 34, the operator merely pushes the bottom edges of the 
trays 34 backwardly into position where the bottom edges are supported on 
the sloping surface 36. (See also FIGS. 15 and 16). 
The trays 34' may have tabular tops 101 (as shown in FIG. 11) for easy 
manipulation, and they may also have slots or cutouts 102' therein so that 
the sheets held between may be visible. 
The trays 34' may also have the side edges shaped as shown in FIG. 11, with 
a bottom portion 103 approximately 91/2" wide, an intermediate portion 104 
approximately 81/2" wide, another intermediate portion 105 approximately 
81/4" wide, and an upper portion 106 approximately 8" wide. This 
arrangement enables the operator to center the sheets 59 laterally between 
the trays 34'. When the sheets 59 (or envelopes) are quickly inserted 
between the trays 34', the lateral location will not be precise. After the 
sheets 59 or envelopes are placed between the trays 34', the operator may 
bring one finger along the right-hand edge of the trays 34' and another 
finger along the left-hand edge of the trays 34', and by tapping the edge 
of the sheets 59 or envelopes, the items may be centered within the trays 
34'. The lower-portion 103 is the width of a No. 10 size envelope 
(approximately 91/2" long), the portion 104 is the width of an 
81/2".times.11" sheet of paper (the usual size for U.S. business 
purposes). The portion 105 is 81/4" wide, which is the approximate 
dimension of an international A-4 sheet of paper, and the upper portion 
106 is the 8" width of an 8".times.10" sheet of paper used for 
governmental purposes. 
The trays 34 may also be made in different lengths to accommodate 
letter-size paper or legal-size paper, and may also be curved, bowed, or 
shaped so as to support that portion of a sheet 59 which extends upwardly 
beyond the tray 34. 
referring now to FIG. 2, the gear-train mechanism and drive-wheel mechanism 
shown therein illustrates how the knurled wheel 29 and the wheel or 
rotator 31 are all in contact. Additionally, there is provided a series of 
wheels or rotators 38, and 41 operatively interconnected (as by gears 
39-40 or suitable drive mechanism) so as to guide the paper 59 when it 
exits from the machine to a stacking tray or other receiving platform (not 
shown). The last rotator 41 in the train of rotators 29, 38, 41 is also 
operatively disposed adjacent a paper guide 42, which guides the paper 59 
away from the platen 23 and prevents its interrupting the operation of the 
drop sheet feeder. 
In FIGS. 3, 5, 12 and 13, there is illustrated a form of tray-shifting 
mechanism, wherein a finger 43 is carried by the rotator 31 so that when 
the rotator 31 turns, the finger 43 lifts the forward-most tray 44 away 
from the stack of trays 34, causing an opening to appear between it and 
its next adjacent tray 34, and permitting the sheet 59 held between those 
trays 44, 34 to drop against the platen 23. The dotted line positions 
shown in FIG. 3 illustrate how the tray 44 is lifted up and away from the 
stack of trays 34 to create the opening between it and the next adjacent 
tray 34. 
Referring now to FIGS. 5, 12 and 13, the tray shifter operation can be more 
clearly understood. 
The knurled wheel 29 rotates on the shaft 30 (see FIG. 5) and has a face 
contact (along line 120) with the face of an adjacent wheel 31. A spring 
47 urges the wheel 29 into face contact with the wheel 31, and thus when 
the wheel 29 rotates, the wheel 31 tries to rotate along with it but with 
a limited torque because spring 47 exerts a light force. 
Along a portion of the peripheral surface of the wheel 31, a portion 45 
extends radially beyond the outer diameter of the wheel 31. It may be made 
of a high friction material such as a rubber ring or the like. In FIG. 5, 
it is illustrated as an "O" ring, but, as it will be clearly seen in FIGS. 
3, 12 and 13, only a portion of the circumference of the wheel 31 is so 
formed. 
During normal operations of the platen 23, the knurled wheel 29 rotates in 
the direction of the arrow 121 (shown in FIG. 3) and constantly drives the 
tray shifter wheel 31 in the direction of the arrow 122 because the 
toothed surface 46 of the wheel 29 pushes the raised portion 45 in the 
direction of the arrow 122. 
A pin 123 which is fastened to the wheel 31 travels in slot 124 and 
prevents the wheel 31 from turning in the direction of the arrow 122 any 
farther than the pin 123 can move in the slot 124. 
The light friction between the face of the wheel 29 and the face of the 
wheel 31, forced into contact by the light spring 47, will cause the wheel 
29 to tend to rotate. When the wheel 29-A rotates in the direction 
opposite to the arrow 121, shown in FIG. 3 (as when the platen 23 reverses 
its direction), the raised portion 45 of the wheel 31 is caused to rotate 
in the direction opposite to the arrow 122 shown in FIG. 3. 
There is a substantial force exerted between the wheel 29 and the raised 
portion 45 of the wheel 31, sufficient to cause the finger 43 to lift the 
bottom edge of the tray 44 up and over as shown in FIG. 3. 
When the raised portion 45 has moved past the surface 46 of the wheel 29-A, 
only the light face-to-face friction is exerted on the wheel 31 and its 
continued rotation is stopped when the pin 123 reaches the opposite end 
125 of the slot 124. At this point, the tray shifting has been completed, 
and any continued rotation of the wheel 29-A merely causes a light 
friction drag at line 120 (but causes no further rotation of the wheel 
31). 
This tray shifting sequence is accomplished within approximately 6 
backspacing motions of the typewriter or printer, and when the platen 23 
resumes its normal forward rotation, the friction wheel 29 rotates in the 
other direction and the reverse action turns the wheel 31 in the direction 
of the arrow 122, causing it to be reset or to reach its "home" position. 
In FIG. 13 there is illustrated a mechanism which replaces the face contact 
of the wheels 29 and 29-A and also the spring 47. 
A light hair spring 126 is fastened to the side frame 28 as at 129 with its 
outer end 130 fastened to the stop pin 123. The spring force on the pin 
123 tends to rotate the wheel 31 so that the raised portion 45 may contact 
the toothed surface 46 of the wheel 29 at either end of its rotation. 
In operation, the spring 126 causes slight contact of the raised portion 45 
but not sufficient movement to cause the wheel 31 to operate. It is to be 
understood that the raised portion 45 may be a rubber surface or some 
other rigid material. For instance, if the toothed surface 46 of the wheel 
29 is itself a elastomer or rubber, then the raised portion 45 may be 
metal or some other rigid material. 
In FIGS. 6 and 7, there is illustrated a modified form of tray shifting 
device wherein the bottom edges of the trays 34 have pins or trunnions 48 
extending laterally so as to bring them in contact with the slots 49 in a 
geneva wheel 50 supported on shaft 50-a. As the wheel 50 is rotated in the 
direction of the arrow 51, the pins 48 of the trays 52 will drop into the 
slots 49 and will be moved in the direction of the arrow 53 as the wheel 
50 rotates. 
It is preferred that the pins 48 of the end trays 34 of the group extend as 
at 140 and 141 in FIG. 7-A, with a spring 142 or some other force biasing 
the trays 34 toward the wheel 50. This will insure that pins 140-141 are 
always in contact with the geneva wheel 50 so as to insure entrance and 
exit from the slots 49. As the geneva wheel 50 rotates in the direction of 
the arrow 51, the pin 143 is forced out of the slot 49 because all of the 
pins 140-141 are guided in a guide slot 144. 
It is to be understood that the guide slot 144 may be inclined upwardly 
away from the axis of the geneva wheel 50 and that gravity or some other 
force may be used to urge the pins 140-141 on each side into contact with 
the geneva wheel 50, and that it is not necessary to use a biasing spring 
142 to accomplish this end result. 
In FIGS. 8 and 9, there is illustrated still another form of tray-shifting 
mechanism, wherein a shaped wheel 54 not only lifts an appropriate tray 56 
and moves it forwardly, creating an opening between it and an adjacent 
tray 56, but also separates and holds the trays 56 apart during the 
operation. 
As the wheel 54 (which is a modified form of the geneva wheel 50 shown in 
FIGS. 6 and 7) rotates in the direction of the arrow 55, the tray 56 is 
caught on the shoulder 57 and lifted upwardly as shown in FIGS. 9-B, C, D 
and E, creating the opening 58 (seen particularly in FIG. 9-D), permitting 
the sheet 59 to drop against the platen 23 of the printer 21-a. 
FIGS. 10-A, B and C illustrate a form of tray 34-a wherein a portion 60 is 
bent or shaped so that the trays 34-a may be kept closely adjacent each 
other at the upper end but when the wheel 54 rotates, as previously 
described, it not only lifts the tray 56 upwardly, but also the bent 
portion 60, riding against the bent portion of the adjacent tray 61, 
causes the opening 58 to be created not only at the lower end of the trays 
34-a which are in contact with the wheel 54, but also at the upper end 
near the bent portions 60. 
In FIG. 11, there is illustrated an arrangement whereby a motor 62 is 
mounted on the frame 28. A transfer wheel and gear 63 operate in 
substantially the same manner as the wheel 31 or geneva gear 50, or rotary 
wheel 54, previously described. In this case, the operation of the drop 
sheet feeder is not under the control and instruction of the rotary platen 
23 but can be managed independently. It is preferred that the motor 62 
will get its instructions to turn the wheel and gear 63 from an 
appropriate timing mechanism (not shown) when instruction is fed by the 
word processing equipment (not shown), or by the operator who may press 
the button (not shown) or operate a switch (not shown) to cause the motor 
62 to function. 
In FIGS. 15 and 16, there is illustrated a simple mechanism by which the 
trays 34 can be reset to their original position. An edge 170 of the cover 
or frame of the feeder provides a stop against which the trays 34 may be 
pivoted so as to reset the bottom edges on the inclined surface 36. 
As shown in FIG. 16, the upper end of the trays 34 are moved forwardly by 
the operator causing the forward-most tray 34 to contact the edge 170, as 
at 171, when the operator pulls the upper-end of the trays 34, the bottom 
edges slide from the surface 172 back to the inclined surface 36. 
There is illustrated in FIG. 14 a modified arrangement whereby a pair of 
advancing rollers 190 and 191 receive the falling sheet 59 between them 
and under positive driving action carry the sheet 59 downwardly against 
the guide surface 192 and into position between the platen 23 and the 
drive roller 25. These additional rollers 190-191 provide a paper drive 
when the insert area of the platen 23 is not disposed on the rearward side 
of the platen 23, as shown in FIG. 14. In the arrangement shown in FIG. 
14, a falling sheet 59 may not be caught by the nip between the platen 23 
and the drive roller 25, and this mechanism, as shown in FIG. 14, assures 
proper entry of the paper 59 into the drive mechanism of the printer 21-a. 
It also tends to reduce the side bounce of the sheets 59 as the paper 59 
falls from the feeder into the printer 21-a. 
It is also to be understood that the friction drive of the feeder can be 
replaced by a gear drive connected to most printers or typewriters. Many 
printers have an open gear at one end of the platen to drive sprocket or 
pin-type feeders, and a connection between the feeder and the printer can 
use this mechanism. 
It is also to be understood that the exit roller shaft 41-a preferably 
extends across the face of the feeder as a cross-shaft so as to insure 
that both sides turn at the same time. 
Although the embodiment shown in FIGS. 1, 2 and 3 drive the bottom edge of 
the trays 34 in only one direction, the embodiments shown in FIGS. 6-7 and 
8-9 enable the bottom edge of the trays 34, 56 to be driven in either 
direction in the event that it is desirable to do the shifting both from 
right to left as well as from left to right. 
It is to be understood that the present invention may be embodied in other 
specific forms without departing from the spirit or special attributes 
hereof, and it is therefore desired that the present embodiments be 
considered in all respects as illustrative, and therefore not restrictive, 
reference being made to the appended claims rather than to the foregoing 
description to indicate the scope of the invention.