US1372733A - Cinematograph apparatus and intermittent-feed mechanism therefor - Google Patents

Description

H. WORKIVIAN AND S. J. COX.

CINEMATOGRAPH APPARATUS AND INTERA/IITTENT FEED MECHANISM THEREFOR.

APPLICATION FILED AUG.I, 1918.

1937257330 Patented Mar. 299 A921.,

H. WORKIVIAN AND 8.1. COX. CINEMATOGRAPH APPARATUS AND INTERMITTENT FEED IVIECHANISIVI THEREFOR.

APPLICATION FILED AUG. l. 1918. 1.3??29733., A 19mm/e@ Mm. 299 1921,

2 SHEETS-SHEET 2.

mum/1 554444442( f 0 @A fm #www NETE@ @FFHCO HAROLD WGRKIVIAN, OF GLASGOW, SCGTLAND, AND'SAMUEL JAMES COX, 0F LQNDON, ENGLAND.

GENEMATOGRAH APPARATUS AND INTERMITTENT-FTEED MECHANISM THEREFOR.

Specification of Letters Patent.

Patenten Mar.. ae, taai.

Application iiled. August l, 1918. Serial No. 247,880.

T 0 all whom t may concern Be it known that we, HAROLD VVORKMAN and SAMUEL JAMES COX, subjects of His Majesty King George V, of the United Kingdom of Great Britain and ireland and of the British Dominions beyond the Sea and Eniperor of India, residing at Glasgow, Scotland, and London, England, respectively, have invented certain new and useful lmprovements in Cinematograph Apparatus and intermittent-Feed Mechanism Therefor, of which the following is a specification.

This invention relates to improvements in cinematograph apparatus and in intermittent feed mechanism therefor and more particularly to cinematograph cameras in which tlie intermittent feed mechanism is of the claw type and the object of the invention is to provide new and improved means and arrangements whereby with such a mechanism the rest period of the film is increased relatively to the movement period; also by combining two such movements to provide a cinematograph camera capable of taking a large number of pictures per second, thereby enablin movements which are too rapid to be satis actorily observed by the eye to be photographically recorded and studied afterward by projection at a much slower rate.

rlhe ordinary clauT type movement comprises two arms or levers, which are driven at one end by a crank pin in a circular path clear of the film track, while the other ends have claws or teeth which engage the perforations on the two edges of the film, the two levers rocking upon a fulcrum placed at or near the centers of their lengths, and the fulcrum being guided to and fro in a curved path which more or less approximates to an arc of a circle, the center of which is somewhat on the far side of the film track from the driving crank, and the fulcrum is maintained in its path by a radial link or radial links, or by a suitable cam path or cam paths. With this movement the claws or teeth describe more or less a lD-shaped path,

pulling the film forward in the flat part of the D, and leaving it and returning for the next pull forward on the curved part of the ath.

p With such an intermittent mechanism the film rest period is rather greater than the film movement period and one object of the present invention is to still further increase the rest period of the film relatively to the movement period in this class of mechanism. 'llo this end the invention consists mainly in a cinematograph machine provided with an intermittent feed mechanism of the character described in which the spindle of the crank operating the claw movement is itself driven a driving spindle parallel to but out of line with it, by means of a link connecting two crank pins one on each spindle.

By these means owing tothe eccentric paths of the linked pins relatively to each other a variable angular velocity is imparted by the main driving spindle to the intermediate driving spindle which operates the claw movement, enabling a quick pull slow return motion to be obtained with that movement.

The angular direction in which the main driving spindle is set out of line with the intermediate driving spindle is so arranged relatively to the angular position of the crank pin which operates the claw that the point of the highest angular velocity occurs at or near the center of the pull movement of the claw motion.

rll`he two crank pins on the main and intermediate driving spindles may have the same throw orl radius of revolution, but the crank pin on the main driving spindle hasv preferably a somewhat greater throw or radius of revolution than the crank pin on the intermediate driving spindle and it is not advisable to increase the distance the main drivingspindle is set out of line with the intermediate driving spindle to much if any more than one half the throw of the crank pin on the intermediate driving spindle.

rllhe link connecting the two crank pins may be about the same length as the throw of the crank pin on the intermediate driving spindle.

The link preferably pushes around the crank pin on the intermediate driving spindle and is preferably extended on its following end to form a small weight, and the mechanism is preferably arranged so that this weight helps to balance the weight of the claw movement. This weight may also help to balance the irregular angular movement as it travels away from the center and accumulates energy when the claw movement is in its slower phase, and travels toward the center giving up energy when the claw is approaching its highest velocity.

The claw teeth which engage the perforations in the filmare preferably made so that their points enter the perforations and start the film movement easily and as they enter deeper they are made for a portion of their depth to fit loosely the perforations in the lengthwise direction of the lilm, and the mechanism is so set that the film is brought to rest at the end of its movement by this engagement with the back of the claw which then rises more or less at right angles to the plane of the film until this engagement is released.

By the means above described it is possible to complete the movement period of the film in 120 to 130O movement of the main driving spindle, thus giving a rest period of 240 to 230.

lf two such movements are arranged, one at the back and one at the front, of the film, and they are synchronized in opposite phase with each other, it is possible to apply the arrangement to a cinematograph camera which would be capable of taking successive exposures very rapidly after each other probably up to 150 to 200 or more pictures per second, with exposures per picture of 1/750 second to 1/1000 second.

ln this case or otherwise the claw movement may have two or more claws or teeth L extending through both levers with shoulders against which the levers are bolted, the

fulcrum pins being guided in `their path by two radial links which rock on pins in two bosses one on each side of the film track. rlhe levers on the crank side ofthe fulcrum are preferably bent inward and then parallel again and bored at their ends and riveted over the ends of a short distance piece tube which forms the bearing on the crank pin. The centers of the two bosses on which the radial links rock are preferably slightly on,the far side of the film track from the movement with which they are' connected, and in this case the two movements must be stepped slightly one below the other on the line of the film track say for the distance of two perforations, z'. e., rlhe two main driving spindles of the two mechanisms are preferably directly geared together, and one of vthem is driven from the camera gearing, which is preferably arranged in such a way that the camera can be driven so as to produce several different known number of pictures per second when turning the driving handle two revolutions per second, this ob- Lerares ject being attained either by having two or more' spindles on which the handle can be fixed, or by some gear changing arrangement, or by a combination of both such devices.

We will describe a form of carrying out our invention with the aid of the accompanying drawings in which its application to two synchronized intermittent movements for taking cinematograph pictures at high speed is illustrated.

In the drawings Figure l is a front elevation.

Fig. 2 is a side elevation.

Fig. 3 a vertical section through the casting containing the main driving spindle and the intermediate driving spindle, and

Fig. 4c is a side sectional elevation of the casing illustrating the linking of the crank pins of the main and intermediate driving spindles which are mounted parallel to but out of line with each other.

Referring to the drawings, motion is communicated from a main driving spindle a, of a cinematograph machine of the claw type to the claw movement, by the intermediary of two crank pins f and g, one of which is on the main driving spindle a, and the other of which is on an intermediate driving spin.

dle d, whose axis although parallel with the main driving spindle a, is out of line with it. The aforementioned crank pins f and y are connected to ether by a link e.

Referring to ig. 4f, al indicates the end of the intermediate driving spindle on which is a crank pin 0 (Figs. 2 and 3) which operates the claw movement, and a indicates in dotted outline the end of the main driving spindle on which is the crank pin f; this crank pin f in the case illustrated projects from the face of a gear wheel which forms one of a pair connecting two synchronized intermittent movements for use in a cinematograph camera for high speed work. g indicatesthe crank pin on the intermediate driving spindle ci.

The link e operates between 'the crank pins f and g and by its operation gives high speed to the clawhmovement when this is operating on the lm, the main driving spindle a (see F iget) being mounted with its center say about 3/32 to 3/16 out of line with the axis of the intermediate driving spindle d, and the crank pin o on the intermediate driving spindle 0l which operates the claw movement being set at such an angle that the point of highest angular velocity occurs at or near the center of the pull movement phase of the claw motion.

z' designates the small weighted extension on the following end of the link e, (see Fig.

` 4) which helps to balance the weight of the claw movement, and also helps to balance the irregular angular movement of `the claw.

y designates the claw teeth which are bev- Lerares eled on the upper sides for easy entry and made straight on their lower sides for easy starting ofthe film, but which, when they enter more deeply are made to fit the perforations loosely in the lengthwise direction of the film so that with appropriate setting of the mechanism the film is brought to rest at the end of its movement by engagement with the' back of the claw. f

In the case of the two synchronized movements or otherwise the claw movement may have two or more claws or teeth j, j preferably formed as aforedescribed on each of the levers 7c, k. The fulcrum on which the levers rock is as illustrated the extended ends of a distance pin Z extending through both levers with shoulders against which the levers lo, 7c are bolted, the fulcrum pins being guided in theirpath by two radius links m, m which rock on pins in two bosses one on each side of the film track. The levers, lc, 7a on the crank side of the fulcrum are illustrated as bent inward and then arallel again and bored at their ends and riveted over the ends of a short distance piece tube a which forms the bearing on the crank pin o. rlhe centers of the two bosses on which the radial links vlook are shown as is preferred slightly on the far side of the film track from the movement with which they are connected, and the drawing shows the two movements` as stepped slightly one below the other on the line of the film track say for the distance of two perforations, z'. e., b, 5 are the gears for connecting the two main driving spindles of the two mechanisms, one of these gears being driven from the-camera gearing preferably as before described.

1. intermittent feed mechanism for a cinematograph machine, including in combination, a crank driven claw movement of the character described, a main driving spindle, an intermediate driving spindle for the crank which operates the claw movement, said spindles being mounted parallel to but out of line with each other, two facin crank pins, one on the main driving spindle and the other on the intermediate driving spindle, and a link connecting the said crank pins.

2. intermittent feed mechanism as claimed in claim 1 hereof withv a counterbalance on the following end of the connecting link for the crank pins. v

3. Intermittent feed mechanism for a cinematograph machine, including in combination, two crankfdriven claw movements of'the character described, arranged one on one side of a film track and the other on the opposite side of said track, two main driving spindles, one for each of said claw movements, a gearing synchronously connecting said main driving spindles, and appertaining to eachy of said main driving spindles, an intermediate driving spindle for the crank which operates the respective claw movements, said spindles being mounted parallel to-but out of line with each other, two facing crank pins, one on the main driving splndle and the other onthe intermediate driving spindle, and a link connecting the said crank pins.

n testimony whereof we afx vour signatures.

HARoLD wonKMAN. SAMUEL 'Janes con.

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