US2073225A - Pad roller assembly - Google Patents

Description

PAD ROLLER ASSEMBLYl Filed June 18, 1955 2 sheets-sheet ld i L 45 EM i `FIE'V E Y INVENTORS Ernest R055 BY AxEl EEllasnn i .WMe/M ATTORNEY.

March 9, 1937.

E. Ross ET AL PAD ROLLER ASSEMBLY Filed June 18, 1955 2 Sheets-Sheet 2 INVENTORS. Ernest Ru 5 s ff ATTORNEY Patented Mar. 9, 1937 UNITED STATES PAD ROLLER ASSEMBLY Ernest Ross, Elmhurst, and Axel S. Eliason, Whitestone, N. Y., assignors to United Research Corporation, Long Island City, N. Y., a corpo'- ration of Delaware Application June 18, 1935, Serial No. 27,157

6 Claims.

This invention relates to motion picture apparatus and particularly to the mechanism directly associated with the sprockets and rollers that drive and guide the film through the apparatus.

In the advancing of motion picture lm through cameras, projectors, sound units, printers, and similar apparatus, sprockets are used for advancing the lm past the various action points such as the picture taking and projection apertures, sound translation points, and the printing apertures. The lm should travel or advance smoothly and uniformly over these sprockets and it becomes necessary, therefore, that the film be held on the sprockets at a uniform pressure and in a denite position. This is particularly true in printing apparatus such as the continuous reduction type of printer, wherein a 35 mm. negative, for instance, is being reduced to a 16 mm.

' positive by optical reduction. It is necessary in such printing operations that the two films be held in perfect registry, which means that the drive must be uniform at all times and slippage of thelms on their sprockets be eliminated or reduced to a safe minimum.

The principal object of the present invention, therefore, is to hold a lm on a drive sprocket so that the film travels smoothly and uniformly thereover. Features of the invention are the means provided for maintaining a uniform pressure on the film, the means for equalizing the pressure at all times, and the means for preventing film thickness variations or film splices from affecting the pressure on the film.

Other features and advantages of the invention will be apparent from the following description read in conjunction with the accompanying drawings, in which Fig. l is an elevational view of a pair of pad rollers embodying the invention applied to a reduction printer sprocket.

Fig. 2 is a detail section of the pad rollers of Fig. l taken along the line 2-2.

Fig. 3 is a detail section of the pad rollers of Fig. l taken along the line 3 3.

Fig. 4 is a front elevational View of a pad roller embodying the invention applied to a single drive sprocket.

Fig. 5 is a sectional view of the pad roller of Fig. 4 taken along the line 5 5; and

Fig. 6 is a rear elevation of the pad roller of Fig. 4.

Referring now to Figs. l, 2, and 3, a reduction printer type of sprocket rotatably mounted on a supporting Wall 25 includes a large diameter section 5 and a smaller diameter section 6 which have been assembled to rotate as a single unit after having been adjusted by pins and slots shown at 1 to provide the proper registry between a negative iilm carried by section 5 and a positive film carried by section 6 if the films are properly positioned on their respective sprocket teeth. A pad roller assembly 9 functions to properly hold the negative film on section 5 and a pad roller assembly I0 likewise functions for the positive film on section 6.

The pad roller assembly 9 includes pad rollers I2 and I3 rotatably mounted at the ends of a curved arm I5 to which is pivoted a second curved arm IS which in turn is pivoted yat I1 and rotatably attached to an arm I8 on the opposite side of wall 25. The arm I6 has a bracket 20 extending laterally therefrom in which is threaded a bolt 2l for limiting the travel of the arm I6 and consequently the position of the pad rollers I2 and I3 with respect to sprocket section 5, the bolt 2| abutting an extension 23 mounted on the wall 25 of the printer (see Figs. 2 and 3).

Rotatably mounted on one terminal of the arm I8 is a toggle rod 21 slidable in a bearing 23 which is rotatably mounted in the wall 25. A spring 33 under compression is positioned between the bearing 28 and a shoulder 3| on the rod 2l. intermediate the ends of arm I8, a pneumatic dash pot arm 33 is connected, this arm being connected to the piston of a dash pot 34 which is permitted to rotate about a connection 3B (see Fig. 2).

A threaded bolt 31 is threadedly mounted in the arm I6 for positioning the arm I5 with respect to arm IB. By the adjustment of this bolt the pressure of the pad rollers l2 and I3 may be equalized and-the pad rollers be given a position to conform with the diameter of the section 5 in the event of the use of different size sprockets. In the operation of this pad roller the spring maintains the pressure of the pad rollers at a uniform value upon the film travelling over the section 5. The pad rollers do not come in contact with the surface of the sprocket but are maintained at a distance slightly less than the minimum thickness of the lm by the adjustment of the screw 2I. The dash pot 34 eliminates any jumps of the rollers in the case of inequalities in the film or lm splices passing under the rollers. The dash pot also damps the natural period of the spring 30 and also prevents the pad rollers from striking the sprocket with suicient force to dent the contact surfaces or injure the sprocket teeth when the pad roller is closed.

For the smaller sprocket section 6, the pad roller ID includes a curved arm 40 carrying pad rollers 4I and 42 rotatably mounted at the ends thereof. The arm 46 has pivoted thereto a curved arm 44 which is secured to a shaft 45 rotatably mounted within the Wall 25. An arm 41 on the opposite side of the wall 25 is also secured to shaft 45. The arm 40 is totally within the pitch circle of the teeth of sprocket section 5 while the arm 44 extends Within and Without it. The arm 44 has an extension 45 therefrom which is threaded with a bolt 54 bearing on a stop 55 fastened in the wall 25. This arrangement functions to adjust the position of arm 44 and the bearing pressure of the pad rollers 4l and 42 upon the positive ilm travelling over the sprocket section 6. A bolt 51 and a tension spring 58 function to equalize the pressure of the pad rollers 4| and 42 upon the sprocket section 6 when the proper adjustment is made. A horn 59 is provided on the arm 44 to aid in releasing the pad rollers from the sprocket.

The arm 41 is connected to a toggle rod 48 passing through a rotatable bearing 49, the rod 48 having mounted thereon a coil compression spring 5D in the same manner as rod 21 for assembly 9. A pneumatic dash pot 52 having a piston rod 53 is connected intermediate the ends of rod 41 similar to the construction for assembly 9.

The pad roller IU just described operates in the same manner as the pad roller 9 in that the compression spring 59 maintains a uniform pressure upon the positive lm on the sprocket section 6 While the dash pot 52 damps oscillations and protects the sprocket from shock when the pad rollers are closed.

In both of these pad roller assemblies the springs 311 and 59 also function to hold the pad rollers in an inoperative position away from the sprockets for threading film in the machine. After the pivot connections between the rod 21 and arm I8 and between the rod 48 and the arm 41 have passed dead center, the springs 30 and 50 reverse their action.

Referring noW to Figs. 4, 5, and 6, a pad roller assembly 62 is shown for a single drive sprocket 6|. This pad roller includes a curved arm 63 having mounted at one end thereof a pad roller 64 and intermediate the ends, a pad roller 65. The other end of the arm 63 is secured upon a shaft 66 rotatably mounted within a bearing 8| in a Wall 14. A toggle arm 68 on the opposite side of wall 14 is attached to shaft 56 to rotate With arm 63. Pivoted on the end of arm 58 is a toggle rod B9 slidably mounted in an aperture in a ange of an L-shaped extension 1I (see Fig. 5). Between the ange on the arm 1l and the toggle joint is a compression spring 12 similar to the arrangement of rod 21 and spring 39 in Fig. 1.

This mechanism is all mounted on the Wall 14 which may be the same as Wall 25 in Figs. 1, 2, and 3 if both sprockets are on the same machine. The arm 1l may be attached to the Wall 14 by means of screw 15, the bearing 8| extending through the Wall 14. Arm 63 has an extension 61 which is positioned by a bolt 1E threaded through a stop 11 screwed in the Wall 14. A knurled hand knob 18 is provided for releasing and positioning the pad rollers 64 and 65 on the sprocket 6 I, the bolt 16 adjusting the position of arm 61 and thus providing the desired pressure for the pad rollers upon the film travelling over the sprocket 6I. In this assembly, the spring 12 also functions to hold the pad rollers in an inoperative position for threading the lm after the toggle joint has passed dead center.

To prevent the arm 63 from swinging too far in the open position, a stop adapted to engage the extension 61 is mounted on the Wall 14. In

the modification shown in Figs. 1, 2, and 3, the dash pots limit the open positions of the pad rollers.

What is claimed is:

1. A pad roller assembly for a lm sprocket for accommodating films of diiferent sizes comprising a iirst pad roller assembly including an arm pivoted adjacent one end thereof, a second arm pivoted at the other end of said rst arm, pad rollers mounted on the ends of said second arm, spring tensioning means for maintaining said pad rollers against one of said films at a substantially constant pressure and damping means con nected to said spring tensioning means, and a second pad roller assembly, including an arm pivoted adjacent one end thereof, a second arm, pad rollers mounted at the ends of said second arm, spring tensioning means for maintaining said pad rollers at a substantially constant pressure against another of said lms, and individual dampening means connected to said spring tensioning means for dampening the oscillations of said spring tensioning means.

2. A pad roller assembly in accordance with claim 1 in which said dampening means comprises an individual dash pot connected to said tensioning means.

3. A pad roller assembly for a sprocket for advancing lm of different sizes having their longitudinal axes in a common plane, comprising a supporting wall, an arm pivoted on said wall and extending inside the pitch circle of the teeth of the larger sprocket, a second arm pivoted to said rst arm and having a pad roller at each end thereof, means for adjusting the position of said second arm with respect to said rst arm, a third arm pivoted to said Wall and extending outside the pitch circle of the teeth of the large sprocket, an arm pivoted on said last mentioned arm and having pad rollers rotatably mounted at the ends thereof, and individual tensioning means for each arm attached to said wall.

4. A pad roller assembly in accordance with claim 3 in which each of said tensioning means has an individual dampening means.

5. A pad roller assembly in accordance with claim 3 in which said arms directly supporting said pad rollers have a curvature comparable to the curvature of their respective sprockets.

6. A pad roller assembly for a lm sprocket adapted to accommodate lms of diiferent sizes comprising a rst pad roller assembly including an arm pivoted adjacent one end thereof, a second arm pivoted at the end of said rst arm, pad rollers mounted on the ends of said second arm for maintaining one of said lms at a definite position against one portion of said sprocket, spring tensioning means for maintaining said pad rollers against said iilm at a substantially constant pressure and damping means connected to said spring tensioning means, and a second pad roller assembly including an arm pivoted adjacent one end thereof, a second arm pivoted at the other end of said first arm, pad rollers mounted on the ends of said second arm for maintaining a second lm at a denite position against another portion of said sprocket, and spring tensioning means for maintaining said pad rollers at a substantially constant pressure against said other lm.

ERNEST ROSS. AXEL S. ELIASON.

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