Improvements in the Method of and Apparatus for Bending Straw- board, Pasteboard, and the like.
Year: 1892

page_text: Date of Application, 28th June, 1892-Accepted, 6th Aug., 1892
Improvements in the Method of and Apparatus for Bending Straw-
board, Pasteboard, and the like.
I, TEODOR REMUS, of Dresden, in the Empire of Germany, and of Tabernacle
Street, in the City of London, and Kingdom of Great Britain, Manufacturer, do
hereby declare the nature of this invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:-
Straw-board, paste-board, and the like, especially if of cheap quality, can not
be bent to an acute angle without injury to the outside at the bend (whether
breaking or cracking) unless grooved at the inside or scored upon the outside
but thereby the board is weakened so that objects produced therefrom are less
durable.
The present invention relates to a process and apparatus hereinafter described
whereby even boards of low quality may be bent to acute angles without previous
grooving or scoring and without injury to the outside.
The process consists in "gathering" or pinching the inner layers of the board,
so that the neutral plane is moved outward at the bend sufficiently to prevent
excessive strain and breaking.
The apparatus is shown in its condition of rest and in vertical section in Fig. 1
of the accompanying drawings and at the end of the operation in Fig. 2; the
apparatus is constructed as follows:
a is a plate of such length as to suffice for the longest edges occurring in
practice, a groove a', corresponding in section with the bend to be produced,
passes along the entire plate.
C
Above said groove two plates, hinged to one another are provided covering
the groove; the axis on which the plates turn is centrally over the groove-
check-pieces c, guide the plates, b Beneath the latter are mounted springs d
tending to keep these plates in their horizontal position. Centrally above the.
groove a plunger e is provided; this has a pointed tongue el projecting down-
wards, at either side it is fitted with bars moving inward on the screws f
When at rest the bars fare, by springs g forced away from tongue e¹.
Each of
the longitudinal edges of the bars is made wedge-shaped, by having one side
bevelled, the lower edges being moreover rounded. The upper edges of the bars
bear against shoulders on the tongue-like extension e.
In bending cardboard, straw-board or the like, this apparatus operates as
follows:
The board p, that is to be bent, is placed on the cheek-pieces c, c and plates b, b,
as shown in Fig. 1, and so that the intended bend coincides with the axis on
which the plates b, bare hinged.
Now when the plunger e descends the rounded edges off will to some extent
penetrate into the board by reason of the resistance of the plates b, b, which are,
by the springs d impelled to remain in a horizontal position. When the plunger e
descends further, the increasing pressure overcomes the resistance of the springs d
and the plates b, b, turning on their hinge, give way; that part of the board
which is between the edges, assumes a curvilinear form and the portions under
the edges, f, gradually rise from a position perpendicular to f. f, into an inclined
position. This gradual change of position produces a gradual approaching of the
bars This operation of the parts, together with the resilience of the springs y
and the resistance of the plates b, b, would cause the edges of the bars to slide
down the inclined plane, presented thereto by the surfaces of the board, if their

page_text: entering the board (though but to a slight depth) did not prevent this. As how-
ever they are compelled to move inward when the motion continues they displace
the substance of board that resists them; the effect somewhat resembling what is
sometimes known as "blocking," and the sharper the angle formed by the board
the more that effect takes place. As this displacement of the layers of the board
takes place from both sides of the board towards the bend, it finally raises part of
the latter, and, as the raising on the inside takes place artificially, the neutral plane
at the bend will be found near the outside; and the nearer to the outside the
neutral layer is, the less does the outside require stretching; the strain being thus
diminished, cracking and splitting are obviated. The outer edge of bends inside
by such apparatus will therefore appear quite smooth.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed declare that what I
claim is
For bending straw board paste board, or the like, to an angle without previous
scoring, or grooving,
(1) A method of so "gathering" or pinching the inner layers of the board
that the neutral plane at the bend is moved outward whereby the tension upon
the outer layers is so diminished as to be less than the breaking limit...
(2) The apparatus for carrying this method into practice, characterized by a
plate a with a groove a above which are provided 2 plates b, b, supported by
spring d, and guided by cheek-pieces c, on which the board to be bent is placed
with the line of the intended bend just over the axis on which plates b, bare hinged,
so that, when the plunger e above the board descends, bars f (supported on the
sides of the tongue-like extension el of plunger e and acted upon by springs )
by their rounded edges penetrate into the board and so far "gather," or pinch,
the substance of the board (whilst the latter is bent by the descent of the plunger
and the opposing movement of the plates b, b) as to prevent excessive strain upon
the outer layers.
(3) The hereinbefore described apparatus for bending straw-board, paste-board,
and the like substantially as hereinbefore described and shown in the drawings.
Dated this 28th day of June 1892.
NEWNHAM BROWNE,
Agent for the Applicant.