US2258759A

US2258759A - Sound reproducer

Info

Publication number: US2258759A
Application number: US292929A
Authority: US
Inventors: Ralph H Heacock
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1939-08-31
Filing date: 1939-08-31
Publication date: 1941-10-14
Anticipated expiration: 1958-10-14

Description

R. H. HEACOCK SOUND REPRODUCER Oct.

Filed Aug. 5-1, 1939 zal@ Gttorneg Patented Oct. 14, 1941 UNITED SOUND REPRODUCER Ralph H. Heacock, Gaklyn, N. J., assignortu Radio Corporation of America, a corporation of Delaware Application August 31, 1939, Serial No. 292,929

l Claims.

The present invention relates to an improved sound reproducer and more particularly to an improved pressure roller and pressure roller support for maintaining a sound record lm in contact with a supporting drum adjacent to the reproduction point.

Although referred to as a sound reproducer Where the pressure roller is primarily used, it Will be understood that the pressure roller and pressure roller support are equally capable of use in conjunction With a sound recorder or other simil-ar apparatus Where it is necessary to maintain a lm in uniform contact with a supporting roller.

The present invention is an improvement on the pressure roller described in Loomis et al. Patent 2,019,147 and is intended more particularly for application to sound reproducing apparatus made in accordance with that patent.

In the aforesaid patent7 the pressure roller is composed of a body of felt mounted upon a spindle and is accurately ground concentric with the spindle after mounting and the bracket used is relatively rigid. Such construction, although generally satisfactory,v requires a veryrhigh degree of precision in manufacturing both the roller and the bracket therefor. Further, if the roller is permitted to rest against the lm drum While the apparatus is not in operation there is a tendency for a flat spot to develop on the felt at the point of contact.

In the pressure roller and bracket of the present invention I avoid these diiculties by making the pressure roller of steel instead of felt. This requires an even higher degree of precision in mounting the roller in relation to the lm drum than was the case with the felt roller and I accomplish this by mounting the upper portion of `the roller bracket on a ball-and-socket joint which is capable of being clamped in a xed position when properly adjusted.

One object of the invention is to provide an improved sound reproducing apparatus.

Another object of the invention is to provide an improved pressure roller for sound reproducing apparatus.

Another object of the invention is to provide an improved pressure roller and bracket for sound reproducing apparatus.

Another object of the invention is to provide an improved pressure roller assembly which is capable of extremely precise adjustment.

Other and incidental objects of the invention will be apparent to those skilled in the art from `a reading of the following specification and an s.

lli)

inspection of the accompanying which f Figure 1 is a side View of the portion of a sound head embodying the pressure roller and bracket according to my invention,

Figure 2 is a View partly in section taken along the line 2 2 of Fig. 1 and looking toward the left, and

Figure 3 is a section taken along the line 3-3 of Fig. 2.

Referring irst to Fig. 1, the film F passes down from the picture head around the film drum l0 Which may have a rotary stabilizer mounted on its shaft and to the constant speed sprocket I I. This sprocket II is driven by an appropriate motor and the flatwise bends in the film shown in the drawing serve to absorb the irregularities in the lm motion caused by the sprocket teeth.

Light from the exciter lamp I2 passes through the optical system I3, which focuses it upon the sound track of the film overhanging the edge of the drum I9. The light passes through the sound track to the lens I4 which directs it to the photocell Within the shield l5. f

The film F is held in contact with the drum Il] by the roller 20, Fig. 2, which is pressed lightly against the surface of the film by the spring at 35. This roller 29 is preferably made of` hard steel instead of the felt used in the pressure roller of the Loomis patent above referred to and Vis ground on its surface to the form of an accurate cylinder. The roller 20 is carried upon a spindle 22 which also carries the member 2| fixed to the spindle. The member 2I determines the position of the outer edge of the film and, therefore, the position of the sound track in relation to the optical system I3,v the lm being pressed against the flange of the member 2l by the spring 23 acting against the opposite end of the member 20. This entire assemblage of the roller members 20 and 2I, the shaft 22 and the spring 23 is freely rotatable in the ball bearings 24 and 25, the latter of Which is held in position by-the drawing, in

cap 2S.

The bearings 24 and 25 are carried in the -upper portion 36 of a bracket 9, movable toward and away from the drum I0 about the shaft 21, Which passes through the lower end of the bracket. This shaft 2l carries a nut 28 provided With a clamp screw 29. Adjustment of the nut 28 on the shaft 21 moves the entire bracket and the laterally fixed flange 2l in or out. When the bracket is in the closed position, it is held by the bolt 30 which enters an aperture in the plate 3|. This bolt 30 may be retracted by pulling outwardly on the finger piece 32.

The lower part of the bracket just described carries a shaft 33 on which is hinged the upper portion of the bracket including the member 40 and the other portions hereinafter described. The upper portion of the bracket is urged toward the drum shaft by the ball and spring members 34, 35. the uppermost portion of the bracket, which includes the member 36, directly carrying the bearings and the downwardly extending portion of 4|. This portion 4| has a socket formed therein to receive the ball 38 which is formed on the end of a screw 39 and is carried in the bracket portion 40. A correspondingly hollowed cover plate 3'| is secured to the bracket portion 4| by the

screws

42 and 43. By means of this arrangement the upper bracket portion 36 may be moved in any direction about the center of the ball 38 within certain limits, and it may then be clamped in adjusted position by tightening the

screws

42 and 43.

In adjusting the roller 2|] to exact parallelism with the drum I0, the

screws

42 and 43 are loosened slightly. The lower bracket portion is moved to closed position and the bolt 30 is inserted in the appropriate hole and a small light is placed below the rollers. When the space between the rollers is viewed from the direction of entrance of the lm F, an irregularity in opening as small as one ten-thousandths of an inch may be readily seen and the roller 20 is then adjusted about the center of the ball 38 until it is in accurate parallelism with the `drum ID at the point of tangency. The

screws

42 and 43 are then tightened to maintain the roller 20 accurately in position. The tightening of these screws may not be quite uniform and may pull the roller slightly out of position. In this case, one or the other of the screws is tightened a little more until the roller` is restored to accurate parallelism with the drum.

The portion 45 of the roller 20 is made the same diameter as the middle portion. Likewise, the circular portion 46 of the member 2| is made the same Vdiameter as the middle portion. of the roller 20. In rollers according to the prior art, these end portions were usually made slightly smaller in diameter so as to secure better pressure at the middle of the roller and drum, but I find that making these three portions all of the same diameter tends to cause the film to remain flatter upon the drum and therefore to remain more accurately in focus at the translation point.

It should be noted that the member 2| is held firmly between the shoulder on the shaft 22 and the bearing 25, thereby preventing any endwise motion of the member 2|. On the other reduced end of the shaft 22, I provide a collar 4l which rests against the bearing 24. This collar is made of such a length as to permit vonly one-thirty-second/inch movement of the roller 20 endwise. Since the amount that the roller portion 29 can move is limited, I am able to make the spring 23 considerably stronger than would otherwise be the case. In rollers according to the prior art, the member 2| was free to move along the shaft, and as a consequence when the main portion of the roller moved, or the opposite flange moved against the'spring corresponding to the spring 23, the outer flange could follow, and if Vthe iilm had a bad weave due for example to a poor splice the sound track might momentarily be thrown considerably out of position, causing The bearings 24 and 25 are carried inv disturbing noises in the sound-reproducing system.

It will be apparent from the foregoing description that I have provided both an improved pressure roller and an improved mounting therefor which could greatly improve the performance of the sound reproducer.

Having now described my invention, I claim:

l. In apparatus of the class described, a pivoted bracket provided with a latch, a member hinged to said bracket, spring means biasing said member in one direction about said hinge, a spherical member mounted on said hinged member, and a pressure roller supporting member secured to said spherical member by members having concave faces in frictional engagement with said spherical member.

2. Phonographic apparatus including a drum adapted to support a sound lm adjacent the translation point and a pressure roller adapted to maintain the film in contact with said drum, said pressure roller comprising a barrel portion, two flanged portions and a shaft, one of said anged portions being longitudinally secured on said shaft and the other of said flanged portions being integral with the barrel portion and springpressed along the shaft toward the other flanged portion, said barrel portion being of metal and located accurately linearly tangent to said drum.

3. In apparatus of the class described, a pivoted bracket provided with a latch, a member hinged to said bracket, spring means biasing said member in one direction about said hinge, a spherical member mounted on said hinged member and a pressure roller supporting member secured to said spherical member by members having concave faces in frictional engagement with said Spherical member, said supporting member carrying a pressure roller adapted to maintain the film in contact with said drum, said pressure roller comprising a barrel portion, two flanged portions and a shaft, one of said flanged portions being rigidly secured to said shaft and the other of said fianged portions being integral with the barrel portion and spring-pressed along the shaft toward the other fianged portion, said barrel portion being of metal and located accurately linearly tangent to said drum.

4. A pressure roller for apparatus of the class described, including a shaft, a flanged member longitudinally secured on said shaft, an opposing anged member integral with an intermediate barrel movable along said shaft, and a spring urging said second :flanged member and said barrel toward said first flanged member, the said integral members being formed of a single piece of material.

5. A pressure roller for apparatus of the class described, including a shaft, a flanged member longitudinally secured on said shaft, an opposing anged member integral with an intermediate barrel movable along said shaft, and a spring urging said second fianged member and said barrel toward said first flanged member, said fianged members having circular members integral therewith and adjacent thereto of the same diameter as said barrel, the said integral members being formed of a single piece of material.

6. A pressure roller for apparatus of the class described, including a shaft, a flanged member longitudinally secured on said shaft, an opposing flanged member integral with an intermediate barrel movable along said shaft, and a spring urging said second flanged member and said barrel toward said first anged member, and means on said shaft for limiting the movement of said second member.

'7. A pressure roller for apparatus of the class described, including` a shaft, a anged member longitudinally secured on said shaft, an opposing flanged member integral with an intermediate barrel movable alongr said shaft, and a spring urging said second anged member and said barrel toward said rst anged member, said flanged members having circular members integral therewith and adjacent thereto of the same diameter as said barrel, and means on said shaft for limting the movement of said second member.

RALPH H. HEACOCK.