GB2124193A

GB2124193A - Pin-wheel document feeder

Info

Publication number: GB2124193A
Application number: GB08314236A
Authority: GB
Inventors: Kenjiro Murakami
Original assignee: Suwa Seikosha KK; Epson Corp
Current assignee: Suwa Seikosha KK; Epson Corp
Priority date: 1982-06-04
Filing date: 1983-05-23
Publication date: 1984-02-15
Also published as: JPS58212974A; DE3319976A1; GB2124193B; GB8314236D0

Abstract

A pin-wheel feeder device comprises pins (32) slidably mounted in grooves (33) surrounding the pins (32) on substantially all sides. The pins (32) are each movable by a cam (4) and pin projections (37) between an operative position (34), in which the pin (32) extends outwardly of the wheel (31) so as to drivingly engageable with holes in a document (not shown), and an inoperative position (35) in which the pin (32) does not so extend. The play of the pins (32) in the grooves is restricted by the side walls (39) of the groove and by projections of the side walls engaging in grooves in the pins. <IMAGE>

Description

SPECIFICATION Pin-wheel type document feeding device The present invention relates to a pin-wheel type document feeding device, e.g. a paper feeding device for use in a printer. Although the invention is not so restricted it relates more particularly to a device having a wheel and a plurality of pins slidable radially in the wheel, the device having means for moving the pins inwardly and outwardly of the wheel at fixed positions during the rotation of the wheel.

Although the invention is directed to any novel integer or step, or combination of integers or steps, as herein disclosed and/or as shown in the accompanying drawings, nevertheless according to one particular aspect of the present invention, to which however the invention is in no way restricted, there is provided a pin-wheel type document feeding device comprising a wheel having at least one groove therein; a pin which is slidably mounted in the or each said groove and which is surrounded by the groove on substantially all sides, the pin being movable between an operative position, in which the pin extends outwardly of the wheel so as to be drivingly engageable with holes in a document, and an inoperative position in which the pin does not so extend; cam means for effecting movement of the or each pin between the said operative and inoperative positions; and means for restricting play of the or each said pin.

Preferably, the cam means engages the or each pin externally of its said groove.

The or each pin preferably has at least one projecting portion which engages said cam means, the or each projecting portion extending through and outwardly of an opening in the wheel which communicates with the, or the respective, groove, the walls of the opening being engageable with the or each said projecting portion to restrict angular movement of the pin about its longitudinal axis.

The or each said opening preferably extends to the periphery of the wheel, the cam means being disposed externally of the wheel.

The or each pin may have two spaced apart projecting portions which are respectively disposed on opposite sides of the cam means.

The two projecting portions are preferably aligned with one another.

The or each projecting portion may have at least one flat surface which is slidably engageable with a said wall of the, or the respective, opening.

The or each pin and its respective groove may have interengaging projecting and recessed portions, the said means for restricting play of the pin comprising said inter-engaging projecting and recessed portions.

There are preferably a plurality of angularly spaced apart radially extending grooves each of which has a pin slidably mounted therein.

The wheel is preferably mounted in a wheel frame which is provided with the said cam means.

The invention also comprises a printer, typewriter or the like which is provided at each of the opposite ends of its platen with a device as set forth above, the wheels on the said devices being arranged to rotate in unison with the platen.

According to another aspect of the present invention, there is provided a pin-wheel type document feeding device comprising a wheel having at least one groove therein; a pin slidably mounted in the or each said groove and moveable between an operative position in which the pin extends outwardly of the wheel so as to be drivingly engageable with holes in a document and an operative position in which the pin does not so extend; and cam means for effecting movement of the or each pin between the said operative and inoperative positions, the cam means engaging the or each pin externally of its said groove.

The invention is illustrated, merely by way of example, in the accompanying drawings, in which: Figure 1 is a sectional elevation showing a pin-wheel type document feeding device of first and second embodiments of the present invention, Figure 2 is a top plan view showing a pin and the adjacent peripheral region of the pinwheel document feeding device of the first embodiment, Figures 3(at, (b) are respectively a front view and a side view of the pin of Fig. 2, Figures 4(a), (b) are respectively an elevation, and a top plan view of the wheel of Fig.

2, Figures 5(a), (b) are respectively a front view and a side view of another pin which may be used in the structure of Fig. 2, Figure 6 is a top plan view showing a pin and the adjacent peripheral region of the pin of another embodiment of the present invention, Figures 71a), (b) are respectively a front view, and a side view of the pin of Fig. 6, Figures 8(a), (b) are respectively an elevation, and a top plan view of the wheel of Fig.

6, Figure 9 is a sectional side view of a known pin-wheel type document feeding device, Figure 10 is a top plan view of the pinwheel type document feeding device of Fig.

9, Figure 11 is a sectional side view of the structure shown in Fig. 10, and Figure 12 shows a printer provided with known pin-wheel type document feeding devices.

Referring to Fig. 12, a printer has a printing head 101 which is arranged to reciprocate in the directions of the double-headed arrow A for carrying out printing on recording or other medium (not shown) on a platen 102. Pinwheel type document feeding devices 103, which are provided with pins 104, are respectively disposed on opposite sides of the platen 102 for rotating in synchronism with the platen 102 and for feeding the recording paper. In the printer shown in Fig. 12, the lateral reciprocating motion of the printing head 101 is obstructed by the possibility of the pins 104 striking a nose portion 101a of the printing head 101. In order to eliminate this disadvantage, various mechanisms have previously been suggested for retracting the pins 104 into the wheel of the feeding device when the pins 104 face the printing head 101.An example of such a mechanism is described in U.S. Patent Specification No.

4,022,365.

Figs. 9 10 and 11 show a known pin-wheel type document feeding device. Fig. 9 is a sectional side view of the pin wheel type document feeding device, Fig. 10 is a top plan view of the feeding device of Fig. 9 showing a portion of a pin which is engaged by a cam, and Fig. 11 is a sectional side view of the engaged portion shown in Fig. 10. A wheel 83 held in a wheel frame 86 has radial grooves 82 through which pins 84 can move radially. The wheel frame 86 has a cam portion 81 and projecting portions of the latter engage with recessed portions 85 of the pins 84. The wheel frame 86 holding the wheel 83 therein is disposed adjacent to a platen 95. In the known mechanism of this type, each pin 84 is held by a plurality of parts, i.e. the wheel 83, the cam portion 81 and the wheel frame 86.Hence, there is considerable play in the directions of the double headed arrows 90 and 91, so that it is difficult to control the rocking motion of each pin 84 in the directions of the double headed arrow 90 and the rotating motion of each pin 84 in the directions of the double headed arrow 91. For that reason, the cam may not be completely engaged with the pin 84, which is apt to cause wear of the said engaged portions, reduction of durability, unbalanced or irregular rotation of the wheel 83, and breakage. Furthermore, the relationship between the positions of the pins 84 is inaccurate due to considerable play in the directions of the double headed arrow 90. As a result, the perforations in the paper can be damaged so as to produce a poor paper feed, e.g. an iregular pitch feed.However, if it is intended to reduce the play of the pins 84 in the directions of the double-headed arrow 90 and to control the rotating motion of the pins 84 in the directions of the double headed arrow 91, it is necessary to improve the accuracy to which the respective parts are manufactured, or to enlarge the contact area between the wheel 83 and the pins 84, so that the document feeding device becomes large and costly to manufacture.

An object of the present invention, therefore, is to provide a pin-wheel type document device which may be of simple construction, small, durable and of reduced cost and in which pin play is reduced to prevent the incomplete engagement between the pins and the cam portion, and between the pins and the grooves.

One embodiment of the pin-wheel type document feeding device according to the present invention will now be described with reference to Figs. 1-4.

Fig. 1 is a sectional side view of pin-wheel feeding device according to the present invention. Fig. 2 is top plan view of the device of Fig. 1 showing a pin, and an adjacent peripheral region of the pin wheel. Figs. 3(a) and 3(b) illustrate the shape of the pin shown in Fig. 2 and are constituted by a front view and a side view, respectively. Figs. 4(a) and 4(b) illustrate the shape of the wheel shown in Fig.

2, and are constituted by a front view and a side view, respectively.

A wheel 31 is held in a position adjacent to a platen 5 by a wheel frame 6. Each of a plurality of pins 32 is provided with two projecting portions 37 which extend parallel to each other from the same side of the pin 32. The pins 32 are respectively radially slidable in a plurality of angularly spaced apart radially extending grooves 33 in the wheel 31 so that each pin 32 is movable between an operative position 34, in which the pin 32 extends outwardly of the wheel 31 so as to be drivingly engageable with holes (not shown) in a paper or other document (not shown) mounted on the platen 5, and an inoperative position 35 in which the pin 32 does not so extend, the pin 32 being retracted completely into its groove 33 when the pin 32 is in the inoperative position 35.The projecting portions 37 of each pin 32 engage and are disposed on opposite sides of a cam portion 4 formed on the wheel frame 6, the cam portion 4 effecting movement of each pin 32 between its operative and inoperative positions. Open ings 38 are provided on one side of the wheel 31 from which the projecting portions 37 protrude, each opening 38 communicating both with a respective groove 33 and with the periphery of the wheel 31. Since the project ing portions 37 are engaged with the cam portion 4, as the wheel 31 rotates in syn chronism with the platen 5, each pin 32 slides radially inwardly and outwardly in its groove 33 in dependence upon the configura tion of the cam portion 4, the latter being disposed externally of the wheel 31. When the rotation of the wheel 31 brings a pin 32 into a predetermined region of the cam por tion 4, the pin 32 slides in the respective groove 33 toward the centre of the wheel 31 until the tip of the pin is retracted into the groove 33, as shown at 35. The rocking motion of the pin 32 in the directions of the double headed arrow 40 is controlled by the groove 33 of the wheel 31, and the rotating motion of the projecting portions 37 in the directions of the double headed arrow 41 is also controlled by the opposite end faces or walls 39 of the opening 38.Accordingly, it is possible to substantially eliminate motion in the directions of the arrows 40 and 41 and maintain the pins 32 in the desired positions with high accuracy, so that it is possible to prevent incomplete engagement between the projecting portions 37 and the cam portion 4 and to prevent incomplete engagement between each pin 32 and the opposite end faces 39 of its opening 38 which will cause wear, malfunction and damage to the paper feeding device. As a result, it is possible to produce reliable and stable constructions in which the durability of the wheel 31, the pins 32, the projecting portions 37 and the cam portion 4 is increased.It is also possible to reduce deformation of the perforations in the paper and to reduce irregular pitch feeding, so as to provide a superior paper feeding operation due to the high degree of accuracy in the positional relationship of the pins 32. Additionally, the document feeding device according to the present invention is of simple construction and may be made small so that it may be easily assembled at low cost.

As will be appreciated, in the known construction shown in Figs. 9-11, the engagement between each pin 84 and the cam portion 81 takes place internally of the respective groove 82. This means that, as best shown in Fig. 10, the wall of the groove 82 has to be cut away so as to extend about a portion only of the pin 82. Thus there can be movement of the pin 82 towards the cam portion 81 and there can be angular movement of the pin 84 about its longitudinal axis.

In contrast, in the structure shown in Fig. 2, the engagement between each pin 32 and the cam portion 4 takes place externally of its groove 33 so that such cutting away of the groove 33 does not need to be employed.

Accordingly, each pin 32 is substantially completely surrounded by its groove 33 so that the walls of the latter prevent movement of the pin 32 towards and away from the cam portion 4. Moreover, the walls 39 of each opening 38 are engageable with the projecting portions 37 so that there can be substantially no angular movement of the pin 32 about its longitudinal axis.

Figs. 5(a) and 5(b) illustrate the shape of another pin 22 which may be used in the structure of Fig. 2, Figs. 5(a) and 5(b) being respectively a front view and a side view. In the embodiment shown in Figs. 5(a) and 5(b), instead of the projecting portions 37, two part-cylindrical projecting portions 27a, 27b extend parallel to each other on the same side of the pin 22, the projections 27a, 27b having flat opposite surfaces 1 2 which are slideably engageable with the end faces 39.

Thus it is possible to make the contact area between the projecting portions 27a, 27b and the opposite end faces 39 of the openings 38 larger. This allows the pins 22 to be positioned more stably and accurately, and hence, increases the durability of the document feeding device.

Figs. 1, 6, 7 and 8 show a second embodiment of the present invention which is generally similar to that of Figs. 1 to 4 and which, for this reason, will not be described in detail, like reference numerals indicating like parts.

Fig. 6 is a top plan view showing a peripheral region of the pin of a pin-wheel type document feeding device according to the present invention. Figs. 7(a) and 7(b) illustrate the shape of the pin shown in Fig. 6 and are respectively a front view and a side view.

Figs. 8(a) and 8(b) illustrate the shape of the wheel of Fig. 6 and are respectively an elevation and a top plan view.

In the said second embodiment, pins 2 are employed each of which has two projecting portions 7 which extend parallel to each other from the same side of the pin 2. A wheel 1 held in a wheel frame 6 is disposed adjacent to a platen 5 and has grooves 3 for holding a plurality of pins 2 which are slidable radially therein. Each pin 2 is provided with a recessed or concave portion 9 for engagement with a projecting or convex portion 8 of the respective groove 3. The wheel 1 has on one side thereof openings 14 communicating with the grooves 3, the projecting portions 7 of the pins 2 protruding from the openings 14.

Since the projecting portions 7 of each pin 2 are engaged with the cam portion 4, as the wheel 1 rotates in synchronism with the platen 5, the pin 2 radially slides into or out of the groove 3 according to the configuration of the carn portion 4. When a pin 2 in the wheel 1 is rotated into a particular angular position, the pin 2 slides in the groove 3 toward the centre of the wheel until the tip of the pin is retracted into the groove 3. In addition, the projecting portion 8 of the groove 3 is engaged with the recessed portion 9 of the pin 2, whereby the motions in the directions of the arrows 20, 21 are controlled, so that it is possible to reduce any play of the pin 2 and to hold the pins 2 very accurately in position.

In short, in the first embodiment of the present invention, the motions of the pins 32 in the directions of the arrow 41 are controlled by the opposite end faces 39 of the openings 38. However in the second embodiment of the present invention, the motions of the pins 2 in the directions of both the arrows 20, 21 are controlled by the engagement of the projecting portions 8 of the grooves 3 with the recessed portions 9 of the pins 2.

Thus, in the second embodiment, the posi tins of the pins are determined very accurately, and hence, the advantages of the first embodiment are obtained to an increased extent. Additionally, according to a modification of the second embodiment it is also possible to provide a projecting portion on the pin and a recessed portion on the groove of the wheel.

What is needed is to form interengaging projecting and recessed portions.

As mentioned above, in its preferred form, the document feeding device of the present invention comprises a wheel having thereon a plurality of grooves and openings communicating with the grooves,a wheel frame holding the wheel, a plurality of pins which are radially movable in respective grooves of the wheel, and a cam portion formed on the wheel frame. Each pin has two aligned projections on the same side thereof, with a space therebetween, for engagement with the cam portion. Furthermore, the two projections protrude from the opening and the pin is held play-free. Consequently, any play of the pins towards and away from the cam portion and any rotational motion of the pins is considerably reduced and easily controlled, whereby it is possible to prevent deformation or prevent wear between the projections of the pins and the cam portion due to incomplete engagement therebetween, and also to prevent wear of the pins, the grooves and the openings. It is further possible to prevent rocking motion of the pins. Thus, in accordance with the present invention, it is possible to provide a pin-wheel type document feeding device having a small size, and which is stable and highly reliable, durable, and less costly to manufacture.

Claims

1. A pin-wheel type document feeding device comprising a wheel having at least one groove therein; a pin which is slidably mounted in the or each said groove and which is surrounded by the groove on substantially all sides, the pin being movable between an operative position, in which the pin extends outwardly of the wheel so as to be drivingly engageable with holes in a document, and an inoperative position in which the pin does not so extend; cam means for effecting movement of the or each pin between the said operative and inoperative positions; and means for restricting play of the or each said pin.

2. A device as claimed in claim 1 in which the cam means engages the or each pin externally of its said groove.

3. A device as claimed in claim 1 or 2 in which the or each pin has at least one projecting portion which engages said cam means, the or each projecting portion extending through and outwardly of an opening in the wheel which communicates with the, or the respective groove, the walls of the opening being engageable with the or each said projecting portion to restrict angular movement of the pin about its longitudinal axis.

4. A device as claimed in claim 3 in which the or each said opening extends to the periphery of the wheel, the cam means being disposed externally of the wheel.

5. A device as claimed in claim 3 or 4 in which the or each pin has two spaced apart projecting portions which are respectively disposed on opposite sides of the cam means.

6. A device as claimed in claim 5 in which the two projecting portions are aligned with each other.

7. A device as claimed in any of claims 3-6 in which the or each projecting portion has at least one flat surface which is slidably engageable with a said wall of the, or the respective, opening.

8. A device as claimed in any preceding claim in which the or each pin and its respective groove have interengaging projecting and recessed portions, the said means for restricting play of the pin comprising said interengaging projecting and recessed portions.

9. A device as claimed in any preceding claim in which there are a plurality of angularly spaced apart radially extending grooves each of which has a pin slidably mounted therein.

10. A device as claimed in any preceding claim in which the wheel is mounted in a wheel frame which is provided with the said cam means.

11. A pin-wheel type document feeding device substantially as hereinbefore described with reference to Figs. 1-4; or Figs 1, 2, 4, and 5; or Figs. 1, 6, 7 and 8 of the accompanying drawings.

1 2. A printer, typewriter or the like, which is provided at each of the opposite ends of its platen with a device as claimed in any preceding claim, the wheels of the said devices being arranged to rotate in unison with the platen.

1 3. A pin-wheel type document feeding device comprising a wheel having at least one groove therein; a pin slidably mounted in the or each said groove and movable between an operative position, in which the pin extends outwardly of the wheel so as to be drivingly engageable with holes in a document, and an inoperative position in which the pin does not so extend; and cam means for effecting movement of the or each pin between the said operative and inoperative positions, the cam means engaging the or each pin externally of its said groove.

14. Any novel integer or step, or combination of integers or steps, hereinbefore described, irrespective of whether the present claim is within the scope of, or relates to the same or a different invention from that of, the preceding claims.

15. A pin-wheel type paper feeding device for feeding a paper by pins engaged with perforations of said paper comprising: a wheel, said wheel having thereon a plurality of opening portions and grooves linked with said opening portions; a wheel frame holding said wheel therein; a cam portion formed on said wheel frame; and a plurality of pins each held radially movable in a said groove, each said pin having on the same side thereof two projections elongatedly aligned with a space for engagement with said cam portion, wherein said projections of each said pin protrude from the respective said opening portion and each said pin is held play-free.

16. A pin-wheel type paper feeding device as claimed in claim 15, wherein said projections of each said pin are slidably engaged with opposite end faces of the respective said opening portion, whereby play of said pin is controlled.

1 7. A pin-wheel type paper feeding device as claimed in claim 15, wherein convex and concave portions are provided for mutual engagement between a said groove of said wheel and a said pin, whereby play of said pin is controlled.

18. A pin-wheel type paper feeding device having two projections elongatedly aligned on the same side of a pin thereof for engagement of the pin with a cam portion, openings wherefrom the projections of the pin protrude, and locking portions for controlling play of the pins.