US2713820A

US2713820A - Flat duplicator

Info

Publication number: US2713820A
Application number: US235869A
Authority: US
Inventors: Horii Shinjiro
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-07-11
Filing date: 1951-07-09
Publication date: 1955-07-26
Anticipated expiration: 1972-07-26

Description

J y 1955 SHINJIRO HORlI FLAT DUPLICATOR 2 Sheets-Sheet 1 Filed July 9, 1951 O l TR N0 PW m0 R J? M W H S Ml Y. B r 1 ATTORNEYS July 26, 1955 SHlNJlRO HORII 2,713,820

FLAT DUPLICATOR 2 Sheets-Sheet 2 FIG. 5

Filed July 9, 1951 INVENTOR SHINJIRO HORII,

Eng/WM y'yvmo/ ATTORNEYS United States Patent 0 This invention relates to a flat duplicator of the type employing a stencil stretched on a frame which is pivotally mounted on a bed, and especially to the type in which said stencil frame is supported so as to be automatically lifted when released.

In the duplicator of this type, there are used coil spring tending to hold the stencil frame in an upwardly swung position. It has been also proposed to provide at the pivotal connection a leaf spring which is torsioned by the downward swing of the stencil frame.

In any of the hitherto known types of duplicator, the

tension of the springs and consequently the automatic lifting action of the stencil frame can not be readily adjusted.

In view of the above, an object of this invention is to provide a duplicator having means for automatically lifting the hinged stencil frame, said means comprising a spiral leaf spring like a clock spring tending to exert a lifting action to the stencil frame.

Another object of the invention is to provide a duplicator having means for automatically lifting the stencil frame, in which automatic lifting action can be readily adjusted at will.

In the accompanying drawings illustrating what I now consider the preferred forms of my invention:

Figure 1 is a plan view of the duplicator according to this invention,

Figure 2 is a side View in an enlarged scale of the pivot portion of the duplicator,

Figure 3 is a horizontal plan view thereof, partly in section,

Figure 4 is a side view of a spring box serving as a pivot bearing,

Figure 5 is a similar view of said spring box with its cover removed to illustrate the interior thereof.

Figure 6 is a plan view thereof,

Figure 7 is a side view similar to Figure 2, but showing the position of the pivot when a pile of printing papers are placed upon the bed.

Referring to Figure 1, the bed 1 of a duplicator is provided with

bearing plates

2, 2 fixed in both sides near the rear end of the bed. Each bearing plate 2 has a slot 3 opened upwardly. The stencil frame 4 has pivots 5, each of which being received in said slot 3 in the bearing plate 2. As various parts in the pivot connections on both sides are substantially identical a description of same on one side will serve as a description of both sides As shown in Figures 1 to 3, an arm 6 is fixedly connected to the stencil frame 4, and the pivot 5 is fixed to the rearwardly extended enlarged portion of said arm 6 at a point lower than the center thereof, the pivot 5 being projected inwardly. An antifriction roller may be provided on the pivot 5 as shown in Figure 6. The arm 6 is provided with a cover 7, forming a spring box. 8 is a spiral spring like a spring for a clock, and the outer end 8 thereof extending forwardly is connected to a lug 9 on the arm, whilst the inner end 8" is fixedly 2,713,820 Fat-tented July 26, 1955 ice mounted on a winding shaft 10. This shaft 10 has a knob 11 at the outer end, and is rotatably mounted in second bearing plate 12 on the bed 1. Between the inner side of said second bearing plate 12 and said cover 7 forming the spring box, there is fixedly mounted on said winding shaft 10 a ratchet wheel 13, the boss thereof being fixed to the shaft by means of a pin 14. This pin 14 is utilized for fixing the inner end of the spiral spring 8 to the shaft 10. The boss of the ratchet wheel 13 passes through an oblong slot 7' (Fig. 4) in the cover plate 7, and the inner end of said shaft 10 is not supported by the spring box 67 on the stencil frame 4, so that the pivot 5 on the arm 6 can be shifted vertically relative to the bed 1 along the slot 3 and, at the same time, said arm 6 can be oscillated about the pivot 5 as shown in chain line in Figure 7. Pivotally mounted in the second bearing plate 12, there is a spring pressed stop pawl 15 engaging with the ratchet wheel 13 to hold same in a desired angular position when the spiral spring 8 is wound up by means of the knob 11.

In the above mentioned position, when the stencil frame 4 is lowered to its closed or printing position, the spring 8 is further wound up thereby, so that the frame 4 when released after completing a step of printing will automatically return to its open position by the action of said spiral spring 8.

By releasing the stop pawl 15 from engagement with the ratchet wheel 13 in the closed position of the frame 4, the spring 8 may be unwound to substantially loosen its tension, whereby the automatic lifting action of the frame 4 will become inoperative. When it is desired to bring the frame 4 again into the automatically lifting attitude the knob 11 is manipulated to wind up the spiral spring 8. In this case, the tension of the spiral spring 8 may be varied at will by means of the knob 11, so that the automatic lifting action of the frame 4 may be adjusted at will.

In the duplicator according to this invention, the printing may be effected with a pile of printing papers placed on the bed 1. In this case, when the frame 4 is lowered to its closed or printing position, the pivot 5 guided by the slot 3 will rise by the height corresponding to the thickness of the pile of paper on the bed as shown in Figure 7, but the position of the winding shaft 19 remains unaltered, so that there is a tendency that said pivot 5 is normally pressed downwardly by the action of spring 3. Consequently, the pivot 5 will not be freed from the slot 3 which is open at the upper end.

in the form described above, the stencil frame 4 can not be wholly detached from the bed 1 as the spiral spring 8 is connected at one end to the winding shaft 1% belonging to the bed and at the other end to the frame 4. The stencil may be stretched on the frame 4 with the latter held in the upright position as shown in chain line in Figure 7.

What I claim is:

A flat duplicator employing a stencil comprising, a bed provided with rearwardly positioned bearing plates having a slot for receiving a stencil frame arm pivot, 21 stencil frame including a stencil frame arm and pivot mounted in said slot for lowering and raising the frame from the bed, a spring box projecting from said stencil frame arm enclosing a winding shaft and a spiral leaf spring which is connected at the outer forwardly extending end to said arm and at its inner end to said winding shaft, said Winding shaft being rotatably mounted in a second bearing plate positioned outwardly of said bed bearing plate in order to adjust the tension in said spiral spring, said spring box being provided with an outer covering plate which covering plate is cut out to 2,713,820 3 floatingly suspend said spring box on said winding shaft, a ratchet wheel fixed on said winding shaft and a pawl pivotally mounted on said second bearing plate and engaging said ratchet Wheel to lock said ratchet Wheel in adjusted position. 6

References Cited in the file of this patent UNITED STATES PATENTS Wise Aug. 2, Dick Jan. 4, Balzer Aug. 9, Klaczko Nov. 27,