US 3886863 A
Description (OCR text may contain errors)
United States Patent 1 Carabott et al.
1 STENCIL STAMP WITH AIR VALVE AND PROTECTIVE STENCIL  Inventors: Carmel John Angelo Carabott,
Brenchley; Jaffray Stuart Ross, Worthing, both of England  Assignee: Stenprint Limited, Littlehampton,
England  Filed: Mar. 9, 1973  Appl. No; 339,499
 US. Cl. 101/125; l01/l27.1', l01/l28.l;
401/205  Int. Cl. B41f 15/36; B4ln 1/24  Field of Search 101/125, 405, 406, 327,
lOl/333. 371, 382 MV,127,127.1,128.1', 401/205, 206, 270; 222/422; 128/214 R June 3, 1975 Primary E.\'aminerEdgar S. Burr Assistant ExaminerR. E. Suter Attorney, Agent, or Firm Robert F. OConnel, Dike, Bronstein, Roberts, Cushman & Pfund  ABSTRACT This invention relates to a stencil stamp which can be used for duplicating or printing, and which comprises an ink reservoir, a base to which a pad is attached, and a stencil attached to a frame. According to the invention, the stencil is placed against the ink soaked pad and is held there by the viscosity of the ink, while the frame has a limited freedom of movement in a ver- 156] References cued tical plane so that it can protect the stencil when the UNITED STATES PATENTS stamp is in use, and so that it can provide a simple 2,314,394 3/1943 Guy 401/206 X method for removing the stencil from the stamp. 2,620,731 12/1952 Slonnegcr 101/382 MV 8 Claims, 11 Drawing Figures 29 4 s 6 n 29 I...
FATE-HES M 3 1975 SHEET L 29 5 F|G.l.
PATEHTEUJUH 3 I975 SHEET FIG.3.
STENCIL STAMP WITH AIR VALVE AND PROTECTIVE STENCIL This invention relates to a stencil stamp having a base which comprises an ink reservoir, a pad for feeding ink from the reservoir to the stencil by capillary action, and a stencil adjacent the under side of the pad. The invention can be used for duplicating or for printing, and to this end, it may be filled with either drying printing ink or non-drying duplicating ink.
Previously, stamps have been known where the stencil has been held in position against the pad by being rigidly clamped between a clamping ring and the base. (British Pat. No. 527,960). Using this system, removal of the stencil and its replacement by another, has been a slow and messy job involving handling of the inksoaked stencil.
Stamps are also known where the stencil is fixed to a frame, the frame then being itself attached to the base of the stamp to hold the stencil in place. (British Pat. No. 187,495). The manner of removing the stencil from this stamp is also more complicated and messy than with a stamp according to this invention.
It is a disadvantage of all prior art stencil stamps that the corners and edges of the stencil are subject to abrasion which can markedly lower the expected life of the stencils.
It is an object of this invention to provide a stamp which can be used for duplicating or printing, and which is simple, clean and convenient to use. The stamp may advantageously be used with a stencil of the type described in our co-pending Patent Application Ser. No. 338,879, filed Mar. 7, 1973.
According to the invention, the stencil is carried on a frame which is not directly attached to the base, the stencil thereby being arranged to be releasably secured to the base.
It is an advantage of the invention, that when it is used, the first part of the apparatus that comes into contact with the surface is the frame to which the stencil is attached. This frame is free to move to a limited extent in a vertical direction, and will protect the stencil itself from abrasion by virtue of this movement.
Another advantage of this invention is that the rate of flow of ink through the pad can be adjusted, to cope with any viscosity differences of the ink used.
Yet another advantage lies in that the stencil can be quickly, easily and cleanly exchanged for another, and that the stencils when attached to their frames may be easily stored for re-use.
The invention will now be further described, by way of example, with reference to the accompanying drawings in which:
FIG. 1 is a longitudinal section through a stamp taken on the lines AA in FIG. 2;
FIG. 2 is a view of the under side of the stamp with the pad and its retaining screen removed;
FIG. 3 is a plan view of a stencil attached to a frame for use in the stamp;
FIG. 3A is a section taken on the lines BB in FIG.
FIG. 4 is a sectional view of a capillary valve for incorporation in the handle of the stamp;
FIG. 4A is a section on the lines CC in FIG. 4;
FIG. 5 is a plan view of a washer for incorporation in the valve of FIG. 4;
FIG. 6 is a sectional view of one stencil ejector taken along the lines D-D in FIG. 1;
FIG. 7 is a plan view of a tray in which the stamp can rest when not in use;
FIG. 7A is a view on the lines EE in FIG. 7;
FIG. 8 is a cross-sectional view of a second embodiment of a stamp according to the invention.
The stamp has a base 2, a handle 1, and the handle incorporates a valve 3 for regulating the supply of air to the ink reservoir. The ink reservoir 4 is formed primarily in the base, but may be extended to the interior hollow of the handle. The base 2 consists of an upper plate 9 and a lower plate 10 which are joined rigidly together. The lower plate 10 has apertures 11 through which ink can pass from the reservoir to the pad 5 which is arranged against the lower face of the plate 10. The pad 5 may conveniently be made of a foam rubber material. The pad 5 is held in position against the plate 10 by a retaining screen 6 which is held in position by a collar member 7, the collar member being rigidly fixed to the plate 10.
The stencil frame 12 (see FIG. 3) has a stencil 13 fixed to its lower face, the outer portion of such face being angled (see FIG. 3A) so that its outer edge is lower than its inner edge, for reasons which will be .explained later. The position of the frame 12 when the stamp is in operation is shown by dotted lines in FIG. 2. The stencil is then held against the retaining screen 6 by the viscosity of the ink, and the frame is held in position solely by virtue of the fact that it is attached to the stencil, and thus the frame has a limited freedom of movement in a vertical direction. When the stamp is used, the first point of contact with the material to be printed, will be the outer edge of the lower face of the frame. This provides protection for the stencil against abrasion.
Means for ejecting a stencil with its frame, from the stamp are provided at 8. As can be seen in FIG. 6, the ejectors consist of a lower member 14 and an upper member 15 both of which can be made of any suitable plastics material and can be fastened together to simplify assembly. When the ejectors are operated to eject a frame from the stencil stamp, the lower member 14 bears against a flange 16 of the frame, and depression of the upper member 15 causes the frame 12 to be pushed away from the base of the stand.
Conventional spring loaded pedestals 20 are also provided in each corner of the stamp. These rest on the material to be printed, in such a way that the stencil is maintained clear of the material.
The rate of flow of ink to the stencil is regulated by the valve 3, shown in section in FIG. 4. An air hole 25 is provided in the top of the handle 1. From this hole air flows into the valve, down through the central passage 24, and then passes upwards through the slots 26 (FIG. 4A) in the threaded portion 27 to the controlling part of the valve above. This consists of a porous, compressible body 23 which is sandwiched between two washers 21 with cut-away portions 22. Rotation of the casing 28 provides for compression or expansion of the porous body 23, thus varying the rate at which air can pass through it. In a hot climate, for instance, where the viscosity of the ink will be very low, the air flow through the valve should be reduced, and vice versa.
The retaining screen 6 is coated at its lower corners 29 with an impervious material, to prevent ink flowing out where it is not wanted.