US2887353A - Reproducing apparatus - Google Patents

Description

y 19, 1959 K. A. BARSTROM ETAL 2,887,353;

REPRODUCING APPARATUS 2 Sheets-Sheet 1 Filed July 3, 1956 2565/ V6 A A ApPL F/ER INVENTORS KNUT A. BARSTROM ARTHUR A. KLEBBA FIG.2

I II II II In tr I FIG. 3

ATTORNEY United States Patent'O REPRODUCIN G APPARATUS Knut A. Barstrom, Columbia, and Arthur A. Klehba, Thompsonville, Conn., assignors to Gray Research and Development Company, Inc., a corporation of New York Application July 3, 1956, Serial No. 595,676

12 Claims. (Cl. 346-74) bars for producing point by point contacts through the paper upon which the record is to be produced with conductive blades. Experience has shown that such helical wires or strips are highly susceptible to non-uniform erosion due to the composition of the paper and the passage of current. Moreover, the conventional apparatus as exemplified by these patents has severely limited the speed of operation in order to prevent undesirable damage to the paper itself. I

By virtue of the present invention, in addition to solving these problems, inertia forces have been reduced, wear diminished and registration improved. Consequently, in accordance with this invention much higher writing speeds and higher resolution have been achieved than has been possible with conventional apparatus.

The reproducing apparatus constituting the subject matter of this invention comprises a rotary drum containing a peripheral helical groove adapted to receive a ball, the groove having ball inlet and discharge portions adjacent the ends respectively of the drum, means defining a raceway adjacent the drum constraining the ball to traverse the groove, and ball directing means adjacent the inlet portion for introducing the ball into the groove and raceway. The groove preferably has an intermediate portion of constant pitch, an inlet portion increasing in pitch in the direction of movement of the ball, and a discharge portion decreasing in pitch in the direction of movement of the ball. By employing a ball in this manner, erosion is distributed over its entire spherical surface, greatly extending the life of the apparatus as compared with equipment employing helical wires or strips.

The groove is preferably a circular arc in cross section of less than 180 and the raceway defined by strips having opposed straight edges of relatively low coefficient of friction such as nylon or Teflon. The ball directing means preferably contains a plurality of balls and assumes the form of a conveying tube interconnecting the inlet and discharge portions of the groove. Such tube is preferably maintained full of balls advanced towards the inlet portion of the groove by each ball delivered from the discharge portion of the groove. Thus, it will follow, that such use of multiple balls even further distributes erosion and wear and assures a long life to the apparatus.

A more complete understanding of the invention will follow from a description of the accompanying drawings wherein:

Fig. 1 is a schematic perspective showing, partially broken away, of portions of a system incorporating the present invention;

Fig. 2 is an elevation of a drum produced in accordance with the present invention;

Fig. 3 is an end elevation of the drum shown in Fig. 2;

Fig. 4 is a plan view, partially broken away, of a practical structure incorporating the present invention;

Fig. 5 is a section taken along line 55 of Fig. 4 on a slightly enlarged scale; and

Fig. 6 is a section taken along line 66 of Fig. 4.

The drum 10 as shown in Fig. 1 contains a helical groove 12 whose cross-section is a circular are less than 180. At the left end of the drum 10 as shown in Fig. 1, there is an undercut portion 14 of slightly increasing width extending approximately 270 about the periphery of the drum to a point 16 at which it communicates with an inlet portion 18 of the groove 12 having an increasing pitch to provide uniform acceleration to a ball introduced thereinto until it reaches a point 20 at which it joins the intermediate portion 22 of the groove 12 of constant pitch. This intermediate portion of the groove extends to a point 24 at which it joins, a discharge portion 26 of the groove of decreasing pitch so as to impart constant deceleration to a ball received therein. As the drum 10 is rotated about the axis of its shaft 28, a ball 30 received in the groove 12 is retained therein by a raceway defined by strips 32 of material such as nylon or Teflon having a low coefficient of'friction and tending to lubricate the ball, the strips 32 having straight edges 34 defining a raceway. By virtue of this arrangement, it will follow that when a ball 30 is introduced at the left end of the drum, its initial horizontal movement will be very slight, whereupon it will receive a constant acceleration in the inlet portion 18 of the groove until it enters the intermediate portion 22 of constant pitch whereupon its horizontal travel will be uniform until it enters the discharge portion 26 of the groove in which it will be uniformly decelerated so as to receive a progressively decreasing horizontal movement. Suitably treated paper 36 fed as shown in the direction of the arrow 38 will ride over the strips 32 for engagement with the balls 30 and under a blade 40 of conducting material. As depicted in Fig. 1, a signal to be translated will be supplied to a receiver amplifier 42 having output leads 44 and 46 connected to the shaft 28 and blade 40 respectively. Since the shaft, drum and balls are conducting, the desired electrolytic action will be produced by the passage of current through this circuit.

The assumed direction of rotation of the drum is in dicated by the arrow 48 and the corresponding direction of movement of the ball 30 by the arrow 50.

As shown in Fig. 4, a tube 52 having a substantially 'C-shaped configuration, provides one open end 54 for the reception of the balls as they are delivered from the discharge portion 26 of the groove 12 and its other end 56 in communication with the inlet portion 18 of the groove 12 for supplying balls thereto. The tube 52 is maintained full of these balls so that upon the discharge of each ball from the groove 12, it will force those before it towards the inlet portion of the groove until the leading ball actually enters the undercut portion 14. The parts are preferably designed so that a ball enters the undercut portion after approximately of such portion have passed the end 56 of the tube, thus avoiding any possibility of jamming.

One of a number of ways in which the assembly can be produced is depicted in Fig. 5 wherein the drum 10 is supported between a driving center 58 and a supporting center 60. The driving center is supported in suitable bearings 62 and 64 and carries a pulley 66 driven by a belt 68. The driving connection between the center 58' and the drum 10 is produced by a pin 70 received in a complementary slot 72. The supporting frame 74 also carries the center 60 which is biased towards its end of the drum 10 by means of a helical spring 76. At this end of the drum, a suitable bearing 78is received internally of the drum.

Adjustment of the strips 32 defining the raceway can be effected by screws 80 or in some other equally suitable manner.

As depicted and described for purposes of illustration, the intermediate portion of thegroove occupies an angle of 360. Departurefrom this detail and from others shown and described will suggest themselves to those skilled in the art as modifications of the present invention. Accordingly, the examples set forth herein should not be construed as limiting beyond the scope of the appended claims.

We claim:

1. In reproducing-apparatus a rotary drum containing a peripheral helical groove adapted to receive a ball, a ball in said groove, said groove having ball inlet and discharge portions opening at the ends respectively of said drum, meansdefining a raceway adjacent said drum constraining said ball to traverse said groove, ball directing means adjacent said inlet portion for introducing said ball into said groove and raceway, a blade extending axially of said drum and radially spaced therefrom to define a gap with saidball, said groove having a portion of uniform pitch adjacent said blade, and means for applying signal voltages across said gap.

2. In reproducing apparatus as set forth in claim 1 wherein said groove has an intermediate portion of constant pitch.

3. In reproducing apparatus as set forth in claim 1 wherein said inlet portion increases in pitch in the direction of movementof said ball.

4. In reproducing apparatus as set forth in claim 1 wherein said discharge portion decreases in pitch in the direction of movement of said ball.

5. In reproducing apparatus as set forth in claim 1 wherein said groove has an intermediate portion of substantially constant pitch, said inlet portion increases in pitch in the direction of movement of said ball, and said discharge portion decreases in pitch in the direction of movement of said ball.

6. In reproducing apparatus as set forth in claim 1 wherein said groove has a circular arcuate cross section.

7. In reproducing apparatus as set forth in claim 1 wherein said groove has a circular arcuate cross section of less than 180.

8. In reproducing apparatus as set forth in claim 1 wherein said ball directing means contains a plurality of balls.

9. In reproducing apparatus as set forth in claim 1 wherein said inlet and discharge portions are interconnected by a ball conveying tube.

10. In reproducing apparatus as set forth in claim 9 wherein said tube is maintained full of balls advanced towards said inlet portion by each ball received from said discharge portion.

11. In reproducing apparatus as set forth in claim 1 wherein strips having opposed straight edges define said raceway.

12. In reproducing apparatus as set forth in claim 11 wherein said strips have a relatively low coefficient of friction.

References-Cited inthe file ofthis patent UNITED STATES PATENTS 2,733,116 Fantham et a1 Jan. 31, 1956 ,760,840 7 Gordon Aug. 28, 1956 2,776,336 Clauer Jan. 1, 1957

Images