A two-way envelope includes a body portion, a pair of opposed side flaps, a bottom flap and a seal flap integrally connected to the body panel by a tear line. A fold line extends along the seal flap above the tear line and the side flaps have bold lines extending therealong in positions approximately colinear with the seal flap tear line and defining side flap upper portions having seal adhesive thereon. The side flaps are folded into partially overlapping relation and joined together forming a pocket with the body panel and the bottom flap. The seal flap is folded along the seal flap fold line over the side flap upper portions to seal the pocket for a first trip and the seal flap is removed from the body panel along the seal flap tear line whereupon the side flap upper portions are folded along the side flap fold lines to seal the pocket for a second trip. A method of producing the envelope is disclosed which includes the steps of applying the seal adhesive to the seal flap and the side flap upper portions as a single operation and on the same surface of an envelope blank, and folding the side flaps over the body panel causing the side flap adhesive to face in a direction opposite the seal flap adhesive.

This invention relates to envelopes and more particularly to envelopes 
suitable for reuse after a first mailing by detaching a selected portion 
of the original envelope prior to the second mailing. 
BACKGROUND OF THE INVENTION 
The use of two-way, or returnable mailing envelopes has been recognized as 
facilitating the transaction of business, for example, in the sending out 
of monthly statements by business firms where the customer is expected to 
return a portion of the statement with a remittance to expedite proper 
crediting of payments. Such return envelopes commonly utilized an extended 
seal flap having an upper portion adapted to be severed from the 
connection with the remainder of the seal flap, the remainder having seal 
gum or adhesive thereon for resealing the envelope. By way of example, 
U.S. Pat. No. 3,874,582 discloses such an arrangement wherein the upper 
portions of each of the side flaps together with other portions of the 
envelope, including the original seal flap, is removed allowing a top 
portion, formally integral with the seal flap, to be utilized for sealing 
in preparation for a second mailing. Also note U.S. Pat. No. 3,982,689 
showing a returnable mailing envelope having a compound seal flap 
including an upper portion separated from a lower portion by a tear line 
and seal gum or adhesive strips extending along each portion. 
Prior art returnable envelopes, however, tended to be complex, either in 
structure or in manufacture, necessitating a relatively high cost to the 
user. 
SUMMARY OF THE INVENTION 
In the practice of the present invention, a two-way or reusable envelope is 
provided which is both simple in construction and easily manufactured on 
conventional rotary envelope folding equipment. The body panel has a seal 
flap connected thereto by a tear line and a fold or score line extends 
along the seal flap spaced upwardly from said tear line. A portion of the 
seal flap above the fold or score line has seal gum or adhesive thereon. A 
pair of side flaps are connected to the body panel and have score or fold 
lines therealong which are approximately colinear with the seal flap tear 
line and upper portions above the side flap score lines, also with seal 
gum or adhesive thereon. The side flaps are folded inwardly in partially 
overlapping relation and joined together in the manner of a center seam 
envelope, whereby the seal flap may be folded along the seal flap fold 
line to seal the envelope for a first trip, and the seal flap may be 
removed along the seal flap tear line and the side flap upper portions 
folded along their fold lines to seal the envelope for a second trip. 
Simplicity in manufacture is permitted since the seal gum is applied to the 
seal flap and the side flap upper portions as a single operation and on 
the same surface of the envelope blank. By merely folding the side flaps 
over the body panel, for producing the envelope pocket, the side flap gum 
faces in a direction opposite to the seal flap adhesive allowing the 
return use as noted. 
The principal objects of the present invention are: to provide a two-way 
envelope which is simple in construction; to provide such an envelope 
which is easily utilized by the recipient for its intended purpose with 
minimal instruction; to provide such an envelope construction which is 
easily adaptable to variations in size; to provide a return envelope which 
is simple and inexpensive to produce on conventional rotary envelope 
folding equipment; and to provide such an envelope construction and method 
of making same which permits a significant overall cost saving for the 
user.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the drawings in more detail, the reference numeral 1 generally 
indicates a two-way, or return, envelope embodying this invention. The 
envelope 1 comprises a body panel 2 having an inner surface 3 and an outer 
surface 4. Upper and lower edges 5 and 6 and side edges 7 and 8 surround 
the body panel 2 and a window opening 9 extends therethrough. In this 
example, a transparent window patch 10 is adhesively connected to the body 
panel 2 on the inner surface 3 thereof so as to entirely cover the window 
opening 9. 
A pair of opposed side flaps 11 and 12 exhibit outer edges 13 and 14, and 
are integrally connected to the body panel 2 by score or fold lines 15 and 
16 extending along the body panel side edges 7 and 8. The side flaps 11 
and 12 respectively have inner surfaces 17 and 18 and outer surfaces 19 
and 20, the side flap 12 further displaying an adhesive area 21 extending 
along, and slightly spaced from, the outer edge 14 on the inner surface 
18. 
A bottom flap 22 is integrally connected to the body panel 2 and demarcated 
therefrom by a score or fold line 23 which extends along the body panel 
lower edge 6. An adhesive area 24 is located on the inner surface 25 of 
the bottom flap 22, preferably spaced below the score line 23 and slightly 
spaced upwardly from the lower edge of the bottom flap, as shown in FIG. 
6. 
A seal flap 30 has an inner surface 31, an outer surface 32 and is 
integrally connected to the body panel 2, demarcated therefrom by a tear 
line 33 extending along the body panel upper edge 5. In this example the 
tear line 33 is perforated for ease of tearing, however, a sharp fold line 
can also be used to weaken the connection and thereby control the 
separation upon tearing. A score line 34 extends along the seal flap 30 in 
a position parallel to and spaced upwardly from the body panel upper edge 
5, FIG. 6. The seal flap 30 extends upwardly beyond the score line 34, 
forming an upper portion 35 thereabove, which, in this example, is 
substantially greater in vertical height than the lower portion 36 located 
between the score lines 34 and the tear line 33. Seal adhesive or gum 37, 
for example in the form of spaced spots, is located on the seal flap inner 
surface 31 adjacent the upper edge 38 of the upper portion 35. 
Score or fold lines 42 and 43 extend along the respective side flaps 11 and 
12 in locations preferably approximately colinear with, and continuations 
of, the body panel upper edge 5. The side flaps 11 and 12 respectively 
extend upwardly beyond the score or fold lines 42 and 43 forming upper 
side flap portions 44 and 45 which terminates in upper edges 46 and 47 
positioned below but preferably approximately colinear with the seal flap 
score line 34, FIG. 6. 
The side flap upper portions 44 and 45 respectively have an inner side edge 
48 and 49 which, in the example of FIG. 6, is spaced from the respective 
side edges 50 and 51 of the seal flap 30 forming notch-like openings 52 
and 53 therebetween extending downwardly to or slightly beyond the seal 
flap tear line 33. Seal gum or adhesive 54 and 55 is located on the inner 
surface 56 and 57 of the side flap upper portions 44 and 45 adjacent the 
upper edges 46 and 47. 
In forming the envelope the side flaps 11 and 12 are folded inwardly along 
the body panel side edges 7 and 8, which correspond to the score lines 15 
and 16, and over the body panel inner surface 3. The side flaps 11 and 12, 
due to their respective selected widths, partially overlap each other as 
best illustrated in FIG. 1, and are joined at the adhesive area 21, in the 
fashion of a so-called center seam envelope. The bottom flap 22 is folded 
along the body panel lower edge 6, corresponding to the score or fold line 
23, and is joined to the side flap outer surfaces 19 and 20 along the 
bottom flap adhesive area 24. 
The side flaps 11 and 12 and bottom flap 22, so folded and adhesively 
connected, form a pocket 58 which, prior to the first sealing of the 
envelope, may be opened by entry between the seal flap 30 and the side 
flap upper portions 44 and 45. 
The seal gum or adhesive 37 which is applied to the seal flap 30 is 
preferably in the form of spaced spots, as shown, but, for example, may be 
of more continuous configuration and of the type which does not adhere 
strongly to a mating surface after sealing, so that the seal flap may be 
disconnected from the adhesively engaged surface without substantial 
damage. 
In utilizing the envelope construction as above described, after the 
desired insertion of materials (not shown) into the pocket 58, the seal 
flap 30 is folded along the fold line 34, over the side flap upper 
portions 44 and 45, and sealed against the outer surfaces 19 and 20 of the 
side flaps 11 and 12, to seal the pocket for a first trip. The recipient 
breaks the seal between the seal adhesive 37 and side flap outer surfaces 
19 and 20 and thereby obtains access into the pocket 58 to remove the 
contents thereof. The materials to be returned may then be inserted into 
the pocket 58, with the proper address being displayed through the window 
opening 9, and the seal flap 30 removed from the body panel 2 by tearing 
along the tear line 33, FIG. 3. The removal of the seal flap 30 exposes 
the upper portions 44 and 45 of the side flaps 11 and 12, and particularly 
the seal adhesive 54 and 55 thereon, whereupon the upper portions 44 and 
45 may be folded along the score lines 42 and 43 so that the seal adhesive 
54 and 55 contacts the outer surface 4 of the body panel 2 for resealing 
the envelope, preparing same for a second, or return, trip. 
Alternative embodiments of the envelope structure illustrated in FIGS. 7 
and 8 are similar in construction to the envelope above described, except 
in FIG. 7 the notch-like openings 52 and 53 are not utilized but rather a 
slit 59 forms the side edges 60 and 61 respectively of the seal flap 62 
and side flap upper portion 63. In FIG. 8 the slit is replaced by a tear 
line 64 which may be perforated and, in order to remove the seal flap 65 
at the conclusion of the first trip, a tear is made through the tear lines 
64 to the body panel upper edge tear line 66, which corresponds to the 
tear line 33 in the embodiment of FIG. 6. 
The above described envelope constructions permit simple, direct and rapid 
manufacture with a minimum of operational steps, and on conventional 
rotary envelope folding machinery. While many of the prior art return 
envelopes require more complex and additional manufacturing steps over 
conventional one-way envelopes, the envelope constructions above described 
may be manufactured without such additional or more complex operations. 
One basis for this is the ability to apply the seal adhesive 37, 54 and 55 
as a single operation and on the same surface of the envelope blank 70, 
FIG. 6. Thus, in the conventional seal flap gumming section of a rotary 
envelope folding machine (not shown) multiple blanks 70 are positioned in 
a close-step of staggered formation, and are maintained in this formation 
while seal gum or adhesive may be continuously applied, for example, by a 
conventional application roller (not shown) which is suitably notched so 
as to apply the gum simultaneously along the several strips forming the 
locations of the seal adhesive applications; that is, seal gum 37, 54 and 
55. After drying of the seal gum in the conventional manner (for example, 
see U.S. Pat. No. 3,382,778), the application of adhesive area 21 and 
folding of the side flaps 11 and 12 over the body panel 2 causes the side 
flap gum 54 and 55 to face and remain in a direction opposite to the seal 
flap adhesive 37. Such folding and connection of the side flaps together, 
with additional conventional steps utilized to produce common one-way 
envelopes, such as the application of adhesive to the area 24 and folding 
of the bottom flap, then produces the desired construction. 
It is to be understood that while certain forms of this invention have been 
illustrated and described it is not to be limited thereto except in so far 
as such limitations are included in the following claims.