FR2654847A1 - Device for aiding the photocopying of books - Google Patents

Abstract

This first certificate of addition to the "device for aiding the photocopying of books" provides three improvements making it possible to carry out easy photocopying without tearing of the books, by reducing the vertex angle of the rule, to increase the solidness of the edges by truncating their thinnest end, to reduce the transverse bulk by introducing flat parts in the profile of the "circle arc" improvement. By way of indication, we have integrated these three improvements in an embodiment where the profile consists from the vertex, a flat part, a circular arc tangent to this first plane part, a second flat part which is itself also tangent to the said circular arc, as shown by the figure below.

Description

 This certificate of addition to our request "Aid device for photocopying books" brings some improvements to this device, to make it a more powerful object.

The drawbacks that are remedied here are:
-The books resist too much, are mistreated, and slide on the ruler, if the angle according to which they are opened, is greater than I200.

-The edges materializing the intersection of the planes of the surfaces in contact with the pages on the one hand and in contact with the glass of the photocopiers on the other hand, are too fragile and project a thin black line on the photocopies
-The bulk, in width, of the object in the perfect arc, is too important.

The remedies provided are as follows:
I) Modification of the slope of the base triangle, used for the geometrical construction of the profile of the faces in contact with the pages of the books.

 Contrary to what we had written in the main patent, we were led to increase the slope of the oblique faces, at least in the vicinity of their vertex. But if we effectively reduce the readability of the photocopied texts, it is to little since (cos 3000.86) the text is not reduced by more than 15o /, it is, despite the regression in terms of readability, a progress since the books no longer slide, are no longer spread apart on the ruler and that you should only press lightly to keep them in contact. So at the top of the ruler the total angle is 2 x (9Q -d) or 120 (curry -30).

2) Thick edges
In our main patent we had exposed that in all the embodiments described, the edge common to the faces in contact with the pages of the books on the one hand and to the faces in contact with the glass of the photocopiers on the other hand, was sharp .We had even advised in the perfecting of the arc of a circle, to stop obliquely the intersection of the two types of aforementioned facEs. Now we have been able to observe that if instead of having sharp and simple edges, we had: truncated edges perpendicularly to the faces of the rule, in contact with the glass of the photoco-piles, in a clear way and that if the edges obtained were not too thick, provided that the illumination was sufficient, no black line was observed on the photocopies along these edges.

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The advantages which result from it are a great propffté of execution of the photocopies, and an increased solidity very notably what allows to envisage a use and a marketing more ai -sées. The manufacture is also facilitated.

3) Flattening of the faces in an arc over a certain width from the vertices of each of the two acute angles.

 The slopes of these planar parts are stronger than the arcs of circle which they replace, that the arc of circle is tangent to one, at the top, or that the arc of circle makes an angle of 0 with the face plane of the strip (.face in contact with the glass) when the second slope makes an angle of non-zero value, with the same so-called plane face. As a result, the width of the object is reduced, as is its size.

 We will now describe precisely an embodiment of the object according to all the improvements that we have just exposed. The integration of all the above improvements is not compulsory and the embodiment which we are going to describe is not limiting.

Figure I: is a geometrical figure showing the cross-transverse profile of one of the two symmetrical parts of the rule, and how to construct it.

The segment AD of length D is the base of the triangle ADB which corresponds to a cutting of plate of thickness D, cutting of the Z-which will be removed from the material according to AI'IN
The basic triangle A'IWD A'D is the famous basic triangle from which the profile of the ruler is constructed. The angle BA'D (oo has, as we mentioned above, a value of at minus 300
The triangle B'AD is defined on the basis of the value of D which we choose and the value of the angle of vertex A (ss) which we also choose. The intersection of Hypothenuses AB 'and A'B is the point C through which a radius OC of the circle tangent to these two hy-pothenuses, passes.

The BI and AI 'segments correspond to the flat parts of which we have spoken. It is BI, which has a minimum value of 5 mm, which is determined first, the value of AI 'deducing from those of
CI 'and AC whose value is (D-d +) / cos helps for its part @ has a value such as: d @ = (hD tgss / tg α -tgss).

 CI 'for its part has the same value as CI which is equal to: d / cosR -BI.

 The arc of a circle II 'is tangent to the two flat parts which we have just spoken of, in I and in It. The half-dWite passing through O and C has one of the radii of the circle tangent to the same two flat parts; all the circles having this double tangency have @ suni @ radius which belongs to this half-line OC and are therefore concentric. This particular radius makes an angle of value (α + ss) / 2 with the perpendicular to AD (angle}).

The value of R radius of a biting circle is R = CI / tg ((α -ss / 2)
To make an object that does not expand the letters of a text to be photocopied too much, choose D, and BI so that
R can be big enough
The value of 50 mm for R, for D = 30 mm and BI 8.2 mm with 9 = I5, is sufficient.

-The thickness "e" must not be too large; the value 0.5 mm is suitable. Note that then the total height for h = 12 mm becomes 12.5 mm. This height does not reveal any fuzzy because we had determined 12 mm leaving us a certain margin of safety. (always with polymethyl methacrylate) The angle u has no minimum value.

With these improvements we obtain an object that is sufficiently efficient, but which is far from its most complete form.

Claims (4)

 PV: NDICATIONs I) Rule according to claim I of the main patent characterized in that it is symmetrical with respect to its median longitudinal plane, and in that its profile is geometrically constructed from a right-angled triangle at the base (α) of 300. 2) Rule according to claim I of this certificate -nent a rectangular, flat part, of width equal to at least 5 mm, of length equal to that of an oblique face, said flat part being inclined at 300 relative to the base of the triangle serving the geometric construction of the assembly, said flat part having for side, the edge at the top of one of the symmetrical parts of the rule. 3) Rule according to claims I and 2 of this certificate characterized in that its symmetrical oblique faces, have a complex pro -fil, composed successively, starting from the top of a flat slope, of a portion of tangent cylinder surface to this first flat slope, and to a second flat slope also tangent to said portion of cylindrical surface, the second slope being inclined at an angle necessarily less than 300. 4) Rule according to claims I or 2 or 3 of this certificate or according to claims 2 or 3 or 4 of the main patent characterized in that the akete corresponding to the apex of the most acute angle (angle α or }) is truncated perpendicular to the face of the ruler, in contact with the glass of photocopiers and in that the thickness resulting from this operation has a value less than or equal to the millimeter.