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Патент USA US3088155

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May 7, 1963
Filed Nov. 2, 17960
2 Sheets-‘Sheet 1
May 7, 1963
Filed Nov. 2, 1960
2 Sheets-Sheet 2
United States Patent 0 MIce
Patented May 7, 1963
The shoe last insert of this invention is composed of
chemically inert plastic material, speci?cally polyethylene.
Walter P. Field, 157 Belmont St, Brochton, Rdass.
Filed Nov. 2, 196:’), Ser. No. 66,725
1 Claim. (ill. 12—l4iil)
shape and dimension, conveniently by injection molding.
This invention relates to shoe lasts, and more particu
It is contoured and for-med to predetermined precise
As presently preferred the insert is of frustum shape
with the larger end of slightly greater cross-sectional
dimension than the last cavity to which it is to be applied
and with the smaller end of slightly smaller cross-sec
larly to inserts or plugs for use therewith.
tional dimension than the shoe last cavity. In one pre
In the manufacture of shoes, one of the ?rst operations
ordinarily is to tack an insole to the bottom of the last. 10 ferred form of the invention, the insert is of frusto-conical
shape and circular cross-section. For certain applica
In the case of wood-bottom lasts such tacks may be
tions, the insert may have a cross-section of elongate
driven directly into the wood of the last, but the result
character, conveniently with two parallel sides joined by
semi-circular arcs. For convenience of insertion the
last. Accordingly it is desirable to provide replaceable
inserts at such places of tacking in order to increase the 15 smaller end of the insert is marginally rounded. As illus
trated herein, the smaller end of the insert is depressed to
life of the last.
ing nail holes tend to cause early deterioration of the
In the case of metal-bottomed lasts it is of course
necessary to provide inserts at the places of tacking be
cause such metal bottoms, usually steel, are impervious
to tacks.
Generally speaking shoe last inserts previously em
ployed have been expensive, di?'icult to apply or replace,
have required too frequent replacement, or have not ?t
adequately, namely ?ush with the adjacent surface of the
form in effect an air trap and the insert is provided with
a shallow groove extending from the larger end of the
insert along the inclined side thereof and around the
smaller end to communicate with said depressed portion.
Such groove provides an :air vent, to permit adequate and
permanent seating of the insert in desired position.
Referring again to the drawings, particularly FIGS. 4
and 5, insert 16 is of frusto-conical shape with the larger
end 18 having a slightly greater diameter than the smaller
end 29. The marginal edges 22 of the smaller end 20
are rounded. The central portion of the smaller end 20
is depressed to form the air trap 24. A shallow groove
26 is shown as extending from the larger end 18 along
surface of an insert. Likewise if the surface of an insert 30 the side of the insert to the smaller end 2!} and along and
across said smaller end to communicate with said de
rises above the adjacent surface of the last, a depressed
pressed portion 24. As illustrated the insert 16 is of
portion will appear in the insole of the resulting shoe.
injection-molded polyethylene.
To illustrate further the matter of poor ?t, if the surf-ace
As illustrated in FIGS. 2 and 3, last 12 is provided with
of an insert is initially higher than the adjacent surface
a drilled cavity 23 of precise diameter and depth. In
of the last, and scouring is required to remove the excess
FIG. 2 insert 16 is shown as partially inserted into the
material from ‘the insert, such scouring not only involves
cavity 28 which may be done by hand with great ease due
substantial labor cost but such operation removes anti
to the shape ‘and precise dimensions of the insert. In
corrosion material ordinarily applied to metal employed
FIG. 3 the insert 16 is shown as driven to the bottom
for last bottoms.
By the present invention, there are provided shoe last 40 of the cavity 23 with the larger end of the insert ?ush with
the adjacent surface of the last.
inserts which obviate difficulties of the prior art indi
So far as illustrative relative dimensions are concerned,
cated above and ‘additionally provide advantages hitherto
and referring to FIGS. 2 and 3, if the cavity 28 is drilled
not available. Shoe last inserts of this invention will be
to a precise diameter of 1/2", the larger outer diameter of
described below, ‘and illustrated in connection with a
the insert may be 0.515” and the smaller outer diameter
speci?c embodiment thereof in the ‘drawings wherein:
To illustrate the matter of ?t, if the top of an insert is
lower than the adjacent surface of the last, during the
processing of the shoe in its manufacture a raised portion
will appear in the insole co-rersponding to ‘a depressed
of the insert may be 0.495". The vertical dimension of
the insert may be made to corerspond to the depth of
the last cavity.
ing a frusto-conical insert of this invention partially
The groove 26 performs a highly important and indeed
inserted in a last cavity;
essential function in this invention in permitting the
FIG. 3 is a view similar ‘to FIG. 2 showing the insert
escape of air from the last cavity during the incorporation
completely inserted in the last cavity;
of the insert therein. Due to the resilient nature of the
FIG. 4 is an elevation of an insert of this invention;
polyethylene and the precise relative dimensions of the
FIG. 5 is a bottom plan view of the insert shown in
insert and the last cavity, the polyethylene tends to ?ow
FIG. 4;
55 and close the groove 26 during the insertion operation and
FIG. 6 is a fragmentary bottom view of a last with an
this ?ow tends to take place to the extent that the poly
insert of elongate cross-section;
ethylene of the insert ?lls the cavity 12 snugly through
FIG. 7 is an elevation of the elongate insert shown in
out its depth. The depressed portion 24 ‘accommodates
FIG. 6;
any additional air at the bottom of the cavity and pre
FIG. 8 is a bottom plan of the insert shown in FIGS.
vents undue pressure such as might cause the insert other
6 and 7;
wise to rise.
FIG. 9 is a vertical section taken on line 9—9 of
Due to the precision character of the insert 16 the larger
FIG. 7;
or upper end thereof lies flush with the adjacent portions
FIG. 10 is a side elevation of a last showing inserts
of the last and hence requires no scouring in the ordinary
applied to side portions of the last; and
FIG. 11 is a rear elevation of a last showing an insert
This feature saves labor and time ‘and precludes the
applied to the rearward portion of the last.
removal of any rust-proo?ng surface from the metal por
In FIG. 1 is shown a last 16 to the bottom of which
tion of the last. In the event however, that .a last cavity
is secured a metal plate 12 by means of fasteners 14.
Last inserts 16 are shown in place, disposed at places 70 should be of insufficient depth, material of the insert
extending above adjacent portions of the last may be
where it is common to drive tacks to hold an insole in
removed in any suitable manner.
place during shoe making operations.
FIGURE 1 is a bottom view of a metal bottomed last;
FIG. 2 is a fragmentary sectional view of ‘a last show
‘It Will be noted that when a contoured insert of this
invention is driven into a corresponding hole or cavity
applying inserts of this invention to any portion of a last
which may be damaged and require repair.
of the last, any air within the cavity and below the insert
is released by means of the air vent or groove.
there is prevented any buildup of air pressure ‘beneath the
insert which would tend to dislocate the insert from its
predetermined position. At the same time, the com
pressive effect of the walls of the cavity radially inwardly
The slight ?owing tendency of polyethylene tends fur
thermore to close up to some extent tack holes left upon
removal of tacks and thus increases the life of the inserts.
The chemical inertness of polyethylene means addi
of the upper portion of the insert tends to close tack holes
when insole-holding tacks have been withdrawn.
The inserts of this invention may be of cross sections
other than the circular cross section speci?cally illustrated
herein. Thus for example, the cross sectional shape may
be of generally long oval character, in which case the last
V _
In FIG. 11, an insert 30 is {shown as incorporated in
the heel end of a last 19, where tacks are frequently driven
to assist in holding a shoe upper in place.
10 tionally that there is no swelling thereof upon the lacquer
ing of the completed last which ordinarily takes places
after the incorporation of the inserts. Any swelling
characteristic otherwise would ‘tend to cause the insert to
rise above the level of ‘the adjacent surface of the last after
cavity will be made of corresponding shape. Other shapes 15 such lacquering operation.
and modi?cations are within the purview ‘of the invention.
It will he understood that the last inserts of this in
vention may be applied to any desired portion of a last
in FIGS. 6 to 11 provides an extended area for the recep
for repair or other purposes.
tion of insole tacks. This modi?cation ?nds highly useful
Having disclosed my invention, what I claim as new
application in the .toe portions of lasts for pointed-toe 20 and desire to secure by Letters Patent ‘of the United
shoes. Insert 30 is ‘of frustum shape and its larger end
States is:
32 has a slightly ‘greater area than the smaller end 34.
A pressure-formed polyethylene fiiusto'econical plug for
Insert 30 in cross-section is of elongate character with
insertion into a recess in a shoe last comprising poly
the two parallel sides 36 and 38 joined by semi-circular
ethylene polymerized to such a state that the material is
arcs 49. The marginal edges 42 of the smaller end 34 are 25 plastic and slightly resilient to receive tacks and tend to.
rounded. The central portion of the smaller end 34 is
close the tack holes when the tacks are removed.
shown as depressed to form the air trap '44. A shallow
References Cited in the ?le of this patent
groove or ?ute 46 extends from the larger end 32 of the
insert down the lateral side 47 thereof ‘and along the
smaller end 34 thereof to communicate with depressed
Wells _________ o. ____ _-__ May 1, 1883
The elongate form of frusto-conical insert illustrated
portion 44. In FIG. 6, insert 30 is shown in place in
pointed-toe last 48. The cross-sectional shape of insert
30 is advantageous because of the relative ease with which
a corresponding insert-receiving cavity may be formed in
the last.
In FIG. 10, inserts 16 and 30 are shown as incorporated
in side portions of last 10, illustrating the possibilities of
iDe Rochemont _______ _;_ Oct; 15, 1918
Shaw _________________ _-' May ‘6, 1930
Lovaglio ____E ______ _-__- Mar. 21, 1939
Petze _________ __-____-_'_._ Nov. 11, 1952
. 782,690
Great Britain ________ __ Sept. 11, 1957
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