Envelope feeder

A stack of envelopes has its lowermost envelope advanced from the stack by two sets of longitudinally spaced kick rollers, which are driven through a gear train by a unidirectional motor. A separator, which includes a feed roll and a restraint roll driven by the unidirectional motor, allows only one envelope to pass therethrough. The gear train includes two sets of interrupted teeth on a gear for stopping advancement of each of the two sets of kick rollers so that another envelope is not advanced from the stack during a cycle of operation. The gear has a third set of interrupted teeth for stopping the feed and restraint rolls after the envelope has passed the separator. The envelope is advanced to a printer by drive rolls, which cooperate with spring biased back-up rolls to form a nip, driven by the unidirectional motor. When the envelope enters the drive rolls, a latch holds the gear having the interrupted teeth from rotating. When the envelope passes the drive rolls, the unidirectional motor is stopped, and the latch is released.

FIELD OF THE INVENTION 
This invention relates to an apparatus for feeding the lowermost envelope 
in a stack of envelopes from the stack and, more particularly, to a drive 
mechanism for insuring that only a single envelope is fed with the use of 
a unidirectional motor. 
BACKGROUND OF THE INVENTION 
Envelopes have previously been fed from the stack of envelopes by feeding 
the lowermost envelope in the stack. However, the prior drive systems have 
required a controllable clutch mechanism or a bi-directional motor so that 
it has been necessary to rotate the motor in reverse for a predetermined 
distance to unlatch a master gear clutch. 
With this prior drive system, it has not been possible to continue cycling 
until the lowermost of the envelopes in the stack has been fed if the 
envelope is not fed during the first attempt. Instead, the prior drive 
systems have required the reversal of the motor to start another cycle 
even if there has been no successful feeding of the lowermost envelope. 
SUMMARY OF THE INVENTION 
The separating and feeding apparatus of the present invention overcomes the 
foregoing problems through utilizing a unidirectional motor in which there 
is no latching of a clutch until the envelope has passed the drive rolls. 
This enables continuous cycling until an envelope has been advanced to the 
drive rolls. 
An object of this invention is to provide a bottom feed of envelopes in a 
stack with a unidirectional motor.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
Referring to the drawings and particularly FIG. 1, there is shown an 
automatic separating and feeding apparatus 10 including a floor 11 of a 
frame 11' on which is supported a stack of envelopes 12 (shown in 
phantom). The envelopes 12 are fed from the stack in the direction of an 
arrow 14. Accordingly, since the front of the apparatus 10 the direction 
from which the envelopes 12 are fed, in FIG. 1, the arrow 14 is at the 
front of the apparatus 10. 
A unidirectional motor 15 is supported on the left side of the apparatus 
10. The motor 15 is connected through a gear train 15', which is 
schematically shown in FIG. 7, to rotate a first set of kick rollers 16 
(see FIG. 1) and a second set of kick rollers 17, which are longitudinally 
spaced from the first set of the kick rollers 16. 
The kick rollers 16 and 17 are employed to advance the lowermost envelope 
12 from the stack. The kick rollers 16 and 17 advance the envelope 12 
through a separator 18, which allows only one of the envelopes 12 to be 
advanced past it. 
The separator 18 includes a feed roll 19 and a restraint roll 20 forming a 
nip therebetween. The feed roll 19 and the restraint roll 20 are driven 
from the motor 15 through the gear train 15' (see FIG. 7). 
Downstream from the separator 18 (see FIG. 1) is a plurality of drive rolls 
21 cooperating with a plurality of back-up rolls 22. The back-up rolls 22 
are resiliently biased against the drive rolls 21 by a H-shaped spring 23 
(see FIG. 8), which is supported on a bottom surface 24 of the floor 11. 
The spring 23 acts against a shaft 25 on which the back-up rolls 22 
rotate. The spring 23 holds the shaft 25 within guides 26 on the bottom 
surface 24 of the floor 11. 
The drive rolls 21 (see FIG. 1) are driven by the motor 15 through the gear 
train 15' (see FIG. 7) to form a nip with the back-up rolls 22 (see FIG. 
1) to advance the envelope 12 from the frame 11' to a process station of a 
printer (not shown). 
If none of the envelopes 12 is resting on the floor 11, a flag 27 (see FIG. 
9) will extend up through a slot 28 in the floor 11 because of a weight 
28', which is attached to the flag 27. This results in an optical sensor 
29, which includes the flag 27, supplying a signal to a microprocessor 
(not shown) that none of the envelopes 12 (see FIG. 1) is available for 
supply to the printer. This causes a signal to appear to a user to supply 
the envelopes 12 to the floor 11 and prevents activation of the motor 15. 
One suitable example of the optical sensor 29 (see FIG. 9) is sold by 
Aleph Corporation as Part No. OJ-265631-601. 
When the motor 15 (see FIG. 1) is energized by a signal from the 
microprocessor to advance the lowermost envelope 12 in the stack on the 
floor 11, the motor 15 (see FIG. 2) rotates a pulley 30 through a belt 31, 
which also passes around a pulley 32 (see FIG. 7) on a shaft 32' of the 
motor 15. The pulley 30 (see FIG. 2), which has a helical gear 33 integral 
therewith, is rotatably supported by a stud 34. The stud 34 is pressed 
into a boss 34' (see FIG. 10) on a left side wall 35 (see FIG. 1) of the 
frame 11' of the apparatus 10 for support thereby. 
The helical gear 33 (see FIG. 2) meshes with a helical gear 36 of a 
compound gear 37. The compound gear 37 includes a hub 38 integral 
therewith. The compound gear 37 has a gear 39 on one side of the helical 
gear 36 and a gear 40 (see FIG. 7) on the other side of the helical gear 
36. 
The hub 38 (see FIG. 11) is rotatably mounted on a stud 41, which has one 
end pressed into a boss 42 (see FIG. 10) extending from the exterior of 
the left side wall 35 for support thereby. The other end of the stud 41 is 
attached to a metal aligner plate 43 (see FIG. 11). 
The gear 39 meshes with a master cam gear 50 (see FIG. 6) to which is 
coupled a master/feed/kick gear 51. The master cam gear 50 has its hub 52 
(see FIG. 4) rotatably supported on a stud 53 (see FIG. 11), which has one 
end pressed into a boss 53' (see FIG. 10) extending from the exterior of 
the left side wall 35 for support thereby. The other end of the stud 53 is 
connected to the metal aligner plate 43 (see FIG. 11). Likewise, the 
master/feed/kick gear 51 (see FIG. 3) has its hub 54 also rotatably 
supported by the stud 53 (see FIG. 1). 
The master/feed/kick gear 51 (see FIG. 3) has a first set of teeth 55 for 
meshing with a first kick roller gear 56 (see FIG. 2). The first kick 
roller gear 56 meshes with an idler gear 57 for transmitting rotation from 
the first kick roller gear 56 to a drive gear 58 for the first set of the 
kick rollers 16. The drive gear 58 is fixed to a shaft 59 having the first 
set of the kick rollers 16 fixed thereto for rotation therewith. 
The master/feed/kick gear 51 (see FIG. 3) has a second set of teeth 60 for 
causing rotation of the second set of the kick rollers 17 (see FIG. 2). 
The teeth 60 (see FIG. 3) mesh with a second kick roller gear 61 (see FIG. 
2), which is fixed to a shaft 62 having the second set of the kick rollers 
17 fixed thereto for rotation therewith. 
The shaft 59 has its ends rotatably supported in bearings 63 (see FIG. 13). 
The bearings 63 are supported by the left side wall 35 (see FIG. 8) and a 
right side wall 64 (see FIG. 13). A spring 65 surrounds the shaft 59 and 
acts on a collar 66 fixed to the shaft 59 to continuously urge the shaft 
59 towards the left side wall 35 (see FIG. 8) to maintain the drive gear 
58 disposed for engagement with the idler gear 57. 
The shaft 62 is similarly rotatably supported in bearings 67 (see FIG. 13). 
The bearings 67 are similarly supported by the side walls 35 (see FIG. 8) 
and 64 (see FIG. 13), and the shaft 62 has a spring 68 and a collar 69 in 
the same manner as the shaft 59. 
The first kick roller gear 56 (see FIG. 12) has its hub 69A rotatably 
supported on the shaft 62. Thus, the first kick roller gear 56 rotates 
independently of the shaft 62. The spring 68 (see FIG. 8) maintains the 
first kick roller gear 56 disposed for engagement with the teeth 55 (see 
FIG. 3) on the master/feed/kick gear 51. 
The idler gear 57 (see FIG. 8) has its hub 69B rotatably supported by a 
stud 69C (see FIG. 11). The stud 69C is detented into a boss 69D (see FIG. 
10) on the left side wall 35 for support thereby and is attached to the 
aligner plate 43 (see FIG. 11). 
As shown in FIG. 3, the teeth 55 are interrupted by an open sector 70. 
Thus, the drive of the first set of the kick rollers 16 (see FIG. 2) is 
stopped before completion of rotation of the master/feed/kick gear 51 (see 
FIG. 3). The amount of rotation of the first set of the kick rollers 16 
(see FIG. 1) is such that their rotation will stop just prior to when the 
trailing edge of the minimum size envelope 12 to be handled by the 
apparatus 10 would reach the kick rollers 16. Without the open sector 70 
(see FIG. 3) in the teeth 55 of the master/feed/kick gear 51, the next 
adjacent of the envelopes 12 (see FIG. 1) would be driven forward from the 
stack. 
Similarly, the teeth 60 have an open sector 71 (see FIG. 3) to interrupt 
the drive of the second set of the kick rollers 17 (see FIG. 2) before 
completion of rotation of the master/feed/kick gear 51. The rotation of 
the second set of the kick rollers 17 is stopped prior to when the 
trailing edge of the minimum size envelope 12 to be handled by the 
apparatus 10 would reach the kick rollers 17. 
The master/feed/kick gear 51 (see FIG. 5) has a third set of teeth 72 for 
meshing with a feed roll gear 73. The feed roll gear 73 drives a feed roll 
shaft 74, which has the feed roll 19 fixed thereto. 
One end of the feed roll shaft 74 is supported by a bearing 75. The bearing 
75 is supported by the bottom of the right side wall 64. The other end of 
the feed roll shaft 74 is similarly supported by a bearing 76 (see FIG. 8) 
in a bearing support 76' extending downwardly from the bottom surface 24 
of the floor 11. 
The feed roll gear 73 (see FIG. 12) is slidably mounted for axial motion 
along the feed roll shaft 74. The feed roll shaft 74 has a flat 77 
cooperating with a flat (not shown) on the inner surface of a hub 78 of 
the feed roll gear 73 to cause rotation of the feed roll shaft 74 when the 
feed roll gear 73 is rotated. 
A spring 79 continuously urges the feed roll gear 73 along the feed roll 
shaft 74 towards the bearing 76. This insures that the feed roll gear 73 
remains in engagement with the teeth 72 (see FIG. 3) on the 
master/feed/kick gear 51. 
The teeth 72 are interrupted by an open sector 80. The open sector 80 
prevents driving of the feed roll shaft 74 (see FIG. 5) at a specific time 
during the feeding of the envelope 12 (see FIG. 1). 
The restraint roll 20 (see FIG. 5) is fixed to a restraint roll shaft 81 
for rotation therewith. One end of the restraint roll shaft 81 is 
rotatably supported in a bearing 82, which is supported by the left side 
wall 35. 
A compression spring 83, which rests on top of the bearing 82, presses the 
restraint roll 20 against the feed roll 19. The other end of the spring 83 
presses against the left side wall 35. The bearing 82 is free to move 
vertically but is contained axially and horizontally in the left side wall 
35. 
The other end of the restraint roll shaft 81 extends through a torque 
limiting clutch 85 and a bearing (not shown) in the right side wall 64. 
Two C-clips (not shown) contain the shaft 81 axially to trap it in the 
right side wall 64. 
The torque limiting clutch 85 includes an inside hub having a flat on its 
inner bore mating with a flat on the right end of the restraint roll shaft 
81, a wound coil spring, and an outer housing 86 made of plastic and 
having a gear 87 molded on one end. The torque limiting clutch 85 is 
mounted on the side wall 64 so that the gear 87 is exposed. The wound coil 
spring provides a predetermined slip torque in the drive direction. 
The restraint roll shaft 81 is driven by a gear 88 on the right end of the 
feed roll shaft 74. The gear 88 meshes with teeth 88' (see FIG. 13) on a 
compound idler gear 89, which yields a 7.14 reduction ratio through its 
teeth 89' meshing with the gear 87 (see FIG. 5). Because the restraint 
roll shaft 81 is rotated in the same clockwise (as viewed from the right 
side of FIG. 5) direction as the feed roll 19, the surfaces at the 
interface of the rolls 19 and 20 are moving in opposite linear directions. 
The clockwise rotation of the feed roll 19 drives the envelope 12 (see FIG. 
1) towards the printer, and the restraint roll 20 (see FIG. 5) is driven 
in the opposite direction. By forming the restraint roll 20 of a harder 
polyurethane (55 Shore A hardness) than the feed roll 19 (45 Shore A 
hardness), the feed roll 19 has a slightly higher coefficient of friction 
to paper so as to have a greater tangential drive force than the restraint 
roll 20. Each of the rolls 19 and 20 has a coefficient of friction to 
paper that is much greater than the coefficient of friction between the 
adjacent envelopes 12 (see FIG. 1). 
The biasing force created by the spring of the torque limiting clutch 85 
(see FIG. 5) is selected so that the restraint roll 20 will rotate with 
the feed roll 19 since the torque resulting from the tangential frictional 
force at its surface is greater than that produced by the torque limiting 
clutch 85. However, the biasing force is not so large as to cause rotation 
of the restraint roll 20 with the feed roll 19 when more than one of the 
envelopes 12 (see FIG. 1) is in the nip between the rolls 19 (see FIG. 5) 
and 20. If it were, this would produce multiple feeding of the envelopes 
12 (see FIG. 1). 
Accordingly, when the rolls 19 (see FIG. 5) and 20 are rotating together to 
bring the envelopes 12 (see FIG. 1) into the nip, the rotation of the 
restraint roll 20 (see FIG. 5) in the same linear direction as the feed 
roll 19 helps pull the envelope 12 (see FIG. 1) into the nip where the 
separation can take place. The restraint roll 20 (see FIG. 5) does not 
rotate against the leading edge of each of the envelopes 12 (see FIG. 1) 
so as to damage the leading edge of each of the envelopes 12. The kick 
rollers 16 and 17 urge the bottom envelope 12 into the nip formed between 
the rolls 19 and 20. 
If multiple envelopes 12 enter the nip formed between the rolls 19 and 20, 
the frictional force from the feed roll 19 guides the bottom envelope 12 
in the direction towards the printer. However, the restraint roll 20 (see 
FIG. 5), which is being driven through the torque clutch 85 in the 
opposite direction at the nip, would tend to drive the upper envelopes 12 
(see FIG. 1) in the opposite direction because the coefficient of friction 
of each of the rolls 19 and 20 is greater than the coefficient of friction 
between the envelopes 12. Therefore, the upper envelopes 12 will be 
stopped and thus separated from the bottom envelope. When this occurs a 
torsional equilibrium is reached between the torque of the torque clutch 
85 (see FIG. 5) and a tangential friction force from the bottom envelope 
12 (see FIG. 1) acting on the restraint roll 20 (see FIG. 5) and a 
tangential force generated by friction between the bottom envelope and the 
next upper envelope, being transmitted through the upper envelopes to the 
restraint roll 20 (see FIG. 5) surface by means of friction. In this state 
the restraint roll 20 will cease to rotate because of the balance. If two 
envelopes 12 do enter the nip of rolls 19 and 20, restraint roll 20 turns 
to drive the top envelope 12 back until this balance is reached. 
The drive rolls 21 are driven from the gear 40 (see FIG. 7) of the compound 
gear 37. The gear 40 meshes with a first driver idler gear 90. The first 
driver idler gear 90 (see FIG. 6) has its hub 91 rotatably supported on 
the stud 53 (see FIG. 11), which rotatably supports the master cam gear 50 
and the master/feed/kick gear 51. 
The first driver idler gear 90 meshes with a second driver idler gear 92 
(see FIG. 1). The second driver idler gear 92 has its hub 93 rotatably 
supported on a stud 94, which is pressed into a boss 94' (see FIG. 10) on 
the left side wall 35 for support thereby. 
The second drive idler gear 92 (see FIG. I) meshes with a drive shaft gear 
95, which is attached to a drive roll shaft 96. The drive roll shaft 96 
has the drive rolls 21 fixed thereto for rotation therewith. The drive 
roll shaft 96 is rotatably supported in bearings (not shown) within the 
side walls 35 and 64. 
As shown in FIG. 6, an over-running spring clutch 97 is located on the hub 
91 of the first driver idler gear 90 and the hub 52 (see FIG. 4) of the 
master cam gear 50. 
As the leading edge of the envelope 12 enters the nip formed between the 
drive rolls 21 and the back-up rolls 22, a spring biased latch lever 98 
(see FIG. 6) is lifted by the envelope 12 (see FIG. 1) to dispose a latch 
or pawl 99 for engagement by a surface 100 (see FIG. 4) of a cam 101 on 
the master cam gear 50. When engagement occurs between the latch 99 (see 
FIG. 6) and the surface 100 (see FIG. 4) of the cam 101, rotation of the 
master cam gear 50 is stopped. 
As the envelope 12 (see FIG. 1) exits from the nip between the drive rolls 
21 and the back-up rolls 22, the latch lever 98 (see FIG. 6) is no longer 
supported by the envelope 12 (see FIG. 1). This results in the latch lever 
98 (see FIG. 6) being pivoted to remove the latch 99 from engagement with 
the surface 100 (see FIG. 4) of the cam 101 on the master cam gear 50. 
At the same time, the motor 15 (see FIG. 2) also stops because an optical 
sensor 102 (see FIG. 6) has sensed the trailing edge of the envelope 12 
(see FIG. 1). The sensor 102 includes a pivotally mounted flag 103, which 
blocks and unblocks a beam of light. The optical sensor 102 is preferably 
the same as the sensor 29 (see FIG. 9). 
As shown in FIG. 4, the master cam gear 50 has an open sector 104 since its 
teeth 105 do not extend around the entire circumference. At the start of 
motor 15 to drive the next envelope 12, the master cam gear 50 is rotated 
to a position in which the teeth 105 will be ready to be engaged by gear 
39 (see FIG. 1). This occurs through friction from the over-running spring 
clutch 97 (see FIG. 6), which transmits sufficient force to allow the 
master cam gear 50 to be turned to the position in which the teeth 105 are 
disposed for cooperation with the gear 39 (see FIG. 1). 
As previously mentioned, the master cam gear 50 (see FIG. 6) is released 
when the spring biased latch lever 98 is no longer raised by one of the 
envelopes 12 (see FIG. 1) passing therebeneath. 
Because the master cam gear 50 (see FIG. 4) has the open sector 104 due to 
some of the teeth 105 missing and the master/feed/kick gear 51 (see FIG. 
3) has the open sectors 70, 71, and 80 because of some of the teeth 55, 
60, and 72, respectively, missing, each of the two gears 50 (see FIG. 6) 
and 51 is deemed to be a gear clutch. 
When the master cam gear 50 (see FIG. 6) is latched by the latch lever 98, 
the open sector 104 of the master cam gear 50 is located where there would 
be meshing with the compound gear 39 (see FIG. 1). This stops rotation of 
the coupled gears 50 (see FIG. 6) and 51. 
While the apparatus 10 (see FIG. 1) has been described as being used with a 
printer, it should be understood that the apparatus 10 could be employed 
with any other mechanism in which it is desired to have the envelopes 12 
fed thereto. 
Because the master cam gear 50 (see FIG. 4) is not latched until the 
envelopes 12 (see FIG. 1) have passed the drive rolls 21, the mechanism 
continues to cycle until one of the envelopes 12 (see FIG. 1) has reached 
the drive rolls 21. This improves the reliability for feeding the 
envelopes 12 that are difficult to feed into the nip formed between the 
feed roll 19 and the restraint roll 20. 
An advantage of this invention is that it does not require any reversal of 
the drive motor to begin a feed cycle. Another advantage of this invention 
is that more than one cycle to feed an envelope may be attempted before 
the drive motor is turned off. A further advantage of this invention is 
that feeding from the bottom of the stack of envelopes occurs without the 
kick rollers or the feed roll acting on the next envelope in the stack 
because of the controlled stopping of the kick rollers and the feed roll 
in accordance with the minimum length of an envelope to be fed. 
For purposes of exemplification, a particular embodiment of the invention 
has been shown and described according to the best present understanding 
thereof. However, it will be apparent that changes and modifications in 
the arrangement and construction of the parts thereof may be resorted to 
without departing from the spirit and scope of the invention.