TELESCOPIC CAMERA CRANE

Description

Technical Field

[0001] The invention relates to a telescopic camera crane for easier manipulation of a cinema- or television-camera.

Background Art

[0002] Camera cranes i.e. the devices for remote manipulation of the camera have been proposed and used for film- and television-program shooting for many years. Most of the presently used cinema camera cranes are telescopic cranes that enable shootings that, however, are difficult to be made using traditional equipment. Some examples of telescopic camera cranes can be found in: publication of international patent application No. WO 89/10894 as well as in the US patent specification No. 4 943 019 corresponding to the preamble of claim 1. All these solutions use a boom consisting of a fixed arm, supported in swivel fashion by a pedestal, and of movable arms telescopically advancing from the fixed arm. The fixed arm is provided with a sliding counterweight to balance the weight of the camera mounted at the end of the outermost movable arm. The position of the counterweight depends on the extension of the movable arms.
In most cases, there is a rope drive to provide the movement of the arms of the telescopic camera crane. The drive of this type is relatively cheap, silent-running and does not require complicated maintenance interventions. Fig. 1 illustrates the kinematic diagram of the typical telescopic crane with a rope drive. The fixed arm 1 houses three movable arms 2, 3 and 4 seated slidably. The rear portion of the fixed arm 1 houses three pairs of winding drums 5, 6 and 7, mounted rigidly on a shaft 8 that is driven from an electric gear-motor (not shown on the diagram). To the movable arms 2, 3 and 4 rope pulleys 10 are attached and the steel driving ropes 9 pass through the pulleys 10. The winding drums (5, 6, 7), while rotating along with the shaft 8, accommodate the respective ends of the ropes 9 to wind them onto. The ropes 9, in turn, make the crane movable arms (2, 3 and 4) to extend or retract while the ropes 9 pass through the pulleys 10. Such solution, although in theory very simple, requires however practically that all components must be made very precisely. This applies particularly to the winding drums, the size of which, particularly their outside diameters, must strictly match the specific geometrical dimensions of the crane. A serious problem may therefore arise if the extension of the crane is required by adding additional movable arms, because apart from the above mentioned manufacturing problems, any additional movable arm will drastically increase the transverse dimensions of the fixed arm 1 that would have to accommodate additional pairs of winding drums with more and greater diameters. Besides, such solution requires the use of very long rope sections with the resulting increased longitudinal elasticity of the whole system and making difficult the precise control of the positions of the camera. This is why all the previously constructed camera cranes have been provided with two or three movable arms only.

Disclosure of Invention

[0003] The goal of this invention is to provide a structure of a telescopic camera crane cheap and easy to construct and easy to extend by adding extra movable arms.
The goal meets telescopic camera crane according to the invention comprising a fixed arm with a movable counterweight and mounted on a pedestal, at least two movable arms advancing telescopically from the fixed arm and a rope-driving mechanisms for driving the movable arms. The rope-driving mechanism of the first movable and the next movable arms constitutes a first and a second winding drum, a first and a second rope pulley and four sections of a substantially inextensible driving rope. The said winding drums of the rope-driving mechanism of the specific driven second movable arm are fastened in swivel fashion to the first movable arm preceding in relation to the driven second movable arm. The first and the second rope pulleys are fastened to the said preceding first movable arm close to its corresponding external and internal ends accordingly. The first section of the driving rope links the first winding drum with the fixed arm that precedes the preceding first movable arm, while the second section of the driving rope links the first winding drum with the driven second movable arm. Additionally the third section of the driving rope links the second winding drum with the driven second movable arm, while the fourth section of the driving rope links the second winding drum with the fixed arm that precedes the preceding first movable arm.
In one embodiment of the present invention the first end of the first section of the driving rope is fastened to the fixed arm that precedes the first movable arm, while the second end of the first section of the driving rope is fastened to the first winding drum. To the first winding drum is also fastened the first end of the second section of the driving rope, the second end of which passes through the first rope pulley and is fastened to the driven second movable arm. The first end of the third section of the driving rope is fastened to the driven second movable arm, while the second end of the third section of the driving rope is fastened to the second winding drum. To the second winding drum is also fastened the first end of the fourth section of the driving rope, the second end of which passes through the second rope pulley and is fastened to the preceding first movable arm.
In another embodiment of the present invention the winding drums of onerope-driving mechanism are mounted in swivel fashion onto a common axle fastened to the preceding first movable arm, being the said axle of winding drums perpendicular to the direction of moving of the movable arms.
In further embodiment of the present invention the first and the second sections of the driving rope of one rope-driving mechanism are two parts of the same continuous rope.
In further embodiment of the present invention the third and fourth sections of the driving rope of one driving mechanism are two parts of the same continuous rope.
Yet, in a further embodiment of the present invention the first movable arm is driven by a toothed belt which runs in parallel to the longitudinal axis of the fixed arm and is extended onto two rolls fastened to the fixed arm.

[0004] The crane according to the present invention combines the advantages of the existing rope-drive systems with a considerably simpler and cheaper structure of the driving mechanisms. This solution makes possible to reduce almost three times the total length of the driving ropes compared to the known solution, what results in considerable reduction of the structure's mass and longitudinal elasticity. Individual rope sections are considerably shorter and have generally comparable lengths, whilst the diameters of the winding drums across the winding system do not affect the functioning of the rope-driving mechanisms. This allows better unification, and consequently decreasing the number of differentiated components of the drive system. Due to the structure of the driving mechanisms, the crane according to the invention can be easily lengthened with additional movable arms.

Brief Description of Drawings

[0005] The object of the invention has been schematically shown on drawings, where:

Fig. 1 presents kinematic diagram of the known telescopic camera crane with three movable arms;

Fig. 2 presents the kinematic diagram of camera crane according to the invention which is functional equivalent of the crane form Fig. 1;

Fig. 3 and Fig 4 present the principle of operation of the drive of the movable arms of camera crane according to the invention.

Mode for Carrying out Invention

[0006] An exemplary camera crane according to the invention has one movable arm 1 having length of 4 m, accommodating three telescopically mounted movable arms 2, 3 and 4, each 3.85 m long. The fixed arm 1 can be mounted in any pedestal, for example on a horizontal axle, being part of the known camera crane carriage with a perpendicular column. Each arm (1, 2, 3 and 4) of the crane has a form of a box girder made of aluminum profiles. The arms are supported telescopically one within another by means of known roll guides or by means of other known linear bearing systems. Rope driving mechanism of the second movable arm 3 (Fig. 3 and Fig. 4) comprises the first (11) and the second (12) winding drum, the first (13) and the second (14) rope pulley and four sections (17, 19, 21 and 23) of a substantially inextensible driving rope, for example steel wire rope having the diameter of 4.2 mm. The winding drums 11 and 12 are mounted in swivel fashion on the common axle 15 fastened to the first movable arm 2, i.e. to the arm that precedes the second movable arm 3 driven by that rope drive. The axle 15 is positioned perpendicularly to the direction of movement of the arm 3. The first rope pulley 13 is fastened to the first movable arm 2 close to its external end. The second rope pulley 14 is fastened also to the first movable arm 2, but close to its internal end. The first end 16 of the first section 17 of the driving rope is fastened to the arm that precedes the first movable arm 2, i.e. to the fixed arm 1 in this case. The second end of the first section 17 of the rope is fastened to the first winding drum 11. To the first winding drum 11 there is also fastened the first end of the second section 19 of the rope, the second end 18 of which passes through the first rope pulley 13 and is fastened to the movable arm being driven by these ropes, i.e. to the second movable arm 3 in this case. The first end 20 of the third section 21 of the rope is fastened to the arm driven by that rope i.e. to the second movable arm 3. The second end of the third section 21 of the rope is fastened to the second winding drum 12, whereas to the same drum 12 there is also fastened the first end of the fourth section 23 of the rope, the second end of which (22) passes through the second rope pulley 14 and is fastened to the first movable arm (2), i.e. to the preceding arm in relation to the arm driven by the said rope sections. The first movable arm 2 can be moved with respect to the fixed arm 1 by means of any suitable drive. In the presented embodiment of the invention, the arm is driven by a toothed belt 26 extended over two toothed rolls 27, one of them being driven through gear by electric motor 28. In known camera crane such toothed belt has been used to change the position of the counterweight 29 and in camera crane according to the invention, such toothed belt can perform the same function additionally. In the presented embodiment, the toothed belt 26 is connected with one end of the connecting rod 24, the second end of which is connected with the first movable arm 2. The connecting rod 24 moves in the elongated slot 25 made in the side wall of the fixed arm 1. The motor 28 rotates the right toothed roll 27 which in turn causes the toothed belt 26 to move. Accordingly, the connecting rod 24 moves the first movable arm 2. When the movement of the belt 26 causes pulling out of the first movable arm 2 from the fixed arm 1, also the first winding drum 11 is shifted. Since the first end 16 of the first section 17 of the rope is fastened to the fixed arm 1, and the second end of this rope section is wound on the first winding drum 11, the movement of the arm 2 forces the drum 11 to rotate, thus starting the winding of the second section 19 of the rope. Since this section of the rope passes through the first rope pulley 13 that is fixed in relation to the first winding drum 11, this section of the rope draws the second movable arm 3 outside. At the same time, due to pulling out of the second movable arm 3 outside, the third section 21 of the rope is unwound from the second winding drum 12, whilst the fourth section 23 of the rope is wound onto the same drum. When the direction of rotation of the motor 28 is changed, also the direction of the movement of the toothed belt 26 changes and the first movable arm 2 begins to retract inside the fixed arm 1. Since the second winding drum 12 is linked with the first movable arm 2, the fourth section 23 of the rope forces the rotary motion of this drum, what in turn causes the third section 21 of the rope to be wound on the same drum (12) and in consequence the second movable arm 3 is pulled into the first movable arm 2.
Both the third movable arm 4 and each next arm are driven in the same manner. As it has been shown on Fig. 2 (where the units fulfilling the same functions in each modules of the crane bear the same reference numbers) both the first and the second winding drum 11 and 12 respectively, that drive the third movable arm 4, are fastened onto the second movable arm 3, which is the preceding arm in relation to the said third (driven) movable arm 4. In this configuration, the first end of the first section 17 of the rope is fastened to the arm 2 that precedes the arm 3 that precedes the arm 4 which is driven by this rope assembly.
The crane according to the invention can have both its winding drums 11 and 14 mounted in swivel fashion onto separate axles, because the drums on the axle 15 rotate only under the tension of the relevant sections of the rope and here it is essential merely that both drums that drive one arm have the same diameter. The partition of the rope that drives one movable arm, into four sections has merely the function to simplify assembly and to reduce the cost of the possible replacement of the damaged section of the rope. However, taking into consideration principle of operation of the crane, the first and the second rope sections (as well as the section third and fourth accordingly) of one rope-driving mechanism can be two parts of the same continuous rope. In such situation, such long continuous rope is attached in one point to its corresponding winding drum.

Claims

1. A telescopic camera crane comprising a fixed arm with a movable counterweight (29) and mounted on a pedestal, at least two movable arms (2,3,4) advancing telescopically from the fixed arm (1) and a rope-driving mechanisms for driving the movable arms (2, 3, 4), characterised in that:

- the rope-driving mechanism of the first movable and the next movable (3, 4) arms constitutes of a first (11) and a second (12) winding drums, a first (13) and a second (14) rope pulley and four sections (17, 19, 21, 23) of a substantially inextensible driving rope;

- the winding drums (11, 12) of the rope-driving mechanism of the specific driven second movable arm (3) are fastened in swivel fashion to the first movable arm (2) preceding in relation to the driven second movable arm (3);

- the first (13) and the second (14) rope pulleys are fastened to the said preceding first movable arm (2) close to its corresponding external and internal ends accordingly;

- the first section (17) of the driving rope links the first winding drum (11) with the fixed arm (1) that precedes the preceding first movable arm (2), while the second section (19) of the driving rope links the first winding drum (11) with the driven second movable arm (3);

- the third section (21) of the driving rope links the second winding drum (12) with the driven second movable arm (3), while the fourth section (23) of the driving rope links the second winding drum (12) with the fixed arm (1) that precedes the preceding first movable arm (2).

2. The telescopic camera crane according to Claim 1, characterised in that:

- the first end (16) of the first section (17) of the driving rope is fastened to the fixed arm (1) that precedes the first movable arm (2), while the second end of the first section (17) of the driving rope is fastened to the first winding drum (11);

- to the first winding drum (11) is also fastened the first end of the second section (19) of the driving rope, the second end of which (18) passes through the first rope pulley (13) and is fastened to the driven second movable arm (3);

- the first end (20) of the third section (21) of the driving rope is fastened to the driven second movable arm (3), while the second end of the third section (23) of the driving rope is fastened to the second winding drum (12);

- to the second winding drum (12) is also fastened the first end of the fourth section (23) of the driving rope, the second end of which (22) passes through the second rope pulley (14) and is fastened to the preceding first movable arm (2).

3. The telescopic camera crane according to Claim 1 or 2, characterised in that the winding drums (11, 12) of one rope-driving mechanism are mounted in swivel fashion onto a common axle (15) fastened to the preceding first movable arm (2), being the said axle (15) of winding drums (11, 12) perpendicular to the direction of moving of the movable arms (2, 3, 4).

4. The telescopic camera crane according to any one of Claims 1 to 3, characterised in that the first (17) and the second (19) sections of the driving rope of one rope-driving mechanism are two parts of the same continuous rope.

5. The telescopic camera crane according to any one of Claims 1 to 3, characterised in that the third (21) and fourth (23) sections of the driving rope of one driving mechanism are two parts of the same continuous rope.

6. The telescopic camera crane according to any one of Claim 1 to 5, characterised in that the first movable arm (2) is driven by a toothed belt (26) which runs in parallel to the longitudinal axis of the fixed arm (1) and is extended onto two toothed rolls (27) fastened to the fixed arm (1).

Ansprüche

1. Ein Teleskopkran für Kamera besteht aus einem festen Arm mit beweglichem Gegengewicht (29), montiert auf einem Sockel, mit mindestens zwei beweglichen Armen (2, 3, 4), die sich teleskopisch vom festen Arm (1) herausstrecken können, sowie ein Seilantriebmechanismen der beweglichen Arme (2, 3, 4), wird dadurch gekennzeichnet, dass:

- die Seilantriebmechanismen des ersten beweglichen Arms und der nächsten beweglichen (3, 4) Arme eine erste (11) und eine zweite (12) Seiltrommel, eine erste (13) und eine zweite (14) Seilrolle und vier Teilen (17, 19, 21, 23) eines nicht verlängerbaren Triebseils bilden;

- die Seiltrommeln (11, 12) des Seilantriebmechanismus des bestimmten angetriebenen zweiten beweglichen Arms (3), schwenkbar am ersten beweglichen zum angetriebenen zweiten beweglichen Arm (3) vorhergehenden Arm (2) befestigt sind;

- die erste (13) und zweite (14) Seilrolle an dem genannten vorhergehenden ersten beweglichen Arm (2), jeweils nahe der entsprechenden äußeren und inneren Enden, befestigt sind,

- der erste Teil (17) des Triebseils die erste Seiltrommel (11) mit dem festen Arm (1) verbindet, der sich vor dem vorhergehenden ersten beweglichen Arm (2) befindet, während der zweite Teil (19) des Triebseils die erste Seiltrommel (11) mit dem angetriebenen zweiten beweglichen Arm (3) verbindet;

- der dritte Teil (21) des Triebseils die zweite Seiltrommel (12) mit dem angetriebenen zweiten beweglichen Arm (1) verbindet, während der vierte Teil (23) des Triebseils die zweite Seiltrommel (12) mit dem festen Arm (1) verbindet, der sich vor dem vorhergehenden ersten beweglichen Arm (2) befindet.

2. Der Teleskopkran für Kamera nach dem Anspruch 1 wird dadurch gekennzeichnet, dass:

- das erste Ende (16) des ersten Teils (17) des Triebseils am festen Arm (1), der dem ersten beweglichen Arm (2) vorsteht, befestigt ist, während das zweite Ende des erste Teils (17) des Triebseils an der ersten Seiltrommel (11) befestigt ist;

- an der ersten Seiltrommel (11) auch das erste Ende des zweiten Teils (19) des Triebseils befestigt ist, dessen zweites Ende (18) durch die erste Seiltrommel (13) überläuft und am angetriebenen zweiten beweglichen Arm (3) befestigt ist;

- das erste Ende (20) des dritten Teils (21) des Triebseils am angetriebenen zweiten beweglichen Arm (3) befestigt ist, während das zweite Ende des dritten Teils (23) des Triebseils an der zweiten Seiltrommel (12) befestigt ist;

- an der zweiten Seiltrommel (12) auch das erste Ende des vierten Teils (23) des Triebseils befestigt ist, dessen zweites Ende (22) durch die zweite Seiltrommel (14) durchläuft und am vorhergehenden ersten beweglichen Arm (2) befestigt ist.

3. Der Teleskopkran für Kamera nach dem Anspruch 1 oder 2 wird dadurch gekennzeichnet, dass die Seiltrommeln (11, 12) eines des Seiltriebmechanismus schwenkbar auf einer gemeinsamen Achse (15), die am vorhergehenden ersten beweglichen Arm (2) befestigt ist, eingesetzt sind, während die genannte Achse (15) der Seiltrommeln (11, 12) senkrecht zur Bewegungsrichtung der beweglichen Arme (2, 3, 4) positioniert ist.

4. Der Teleskopkran für Kamera nach den Ansprüchen 1 bis 3 wird dadurch gekennzeichnet, dass der erste (17) und der zweite (19) Teil des Triebseils eines des Triebmechanismus zwei Teile desselben kontinuierlichen Seils bilden.

5. Der Teleskopkran für Kamera nach den Ansprüchen 1 bis 3 wird dadurch gekennzeichnet, dass der dritte (21) und der vierte (23) Teil des Triebseils eines des Triebmechanismus zwei Teile desselben kontinuierlichen Seils bilden.

6. Der Teleskopkran für Kamera nach den Ansprüchen 1 bis 5 wird dadurch gekennzeichnet, dass der erste bewegliche Arm (2) durch einen Zahnriemen (26) angetrieben wird, der parallel zur Längsachse des festen Arms (1) verläuft und auf zwei am festen Arm (1) befestigten Rückrollen (27) aufgespannt.

Revendications

1. Grue télescopique pour caméra composée d'une flèche immobile, montée sur un socle, avec son contrepoids mobile (29), d'au moins deux flèches mobiles (2, 3, 4) télescopiques qui sortent et rentrent du bras immobile (1), ainsi que des mécanismes qui entraînent un câble pour mouvoir les flèches mobiles (2, 3, 4), caractérisée en ce que:

- le mécanisme à câble actionnant la première flèche mobile et les flèches mobiles suivantes (3, 4) se compose d'un premier (11) et d'un deuxième (12) tambour de treuil, d'une première (13) et d'une deuxième (14) poulie à câble, ainsi que de quatre tronçons (17, 19, 21, 23) du câble entraînant inextensible;

- les tambours de treuil (11, 12) du mécanisme entraînant le câble de la deuxième flèche mobile (3) sont tenus par un axe, permettant la rotation, fixé sur la première flèche mobile (2) qui se trouve devant la deuxième flèche mobile (3);

- la première (13) et la deuxième (14) poulie à câble sont fixées à cette première flèche mobile avant (2), près de ses deux extrémités - respectivement - l'extrémité extérieure et intérieure;

- le premier tronçon (17) du câble entraînant raccorde le premier tambour de treuil (11) à la flèche immobile (1), qui se trouve devant la première flèche avant (2), alors que le deuxième tronçon (19) du câble entraînant raccorde le premier tambour de treuil (11) à la deuxième flèche mobile ainsi entraînée (3);

- le troisième tronçon (21) du câble entraînant raccorde le deuxième tambour de treuil (12) à la deuxième flèche mobile (3), alors que le quatrième tronçon (23) du câble entraînant raccorde le deuxième tambour de treuil (12) à la flèche immobile (1) qui se trouve devant la première flèche avant mobile (2).

2. Grue télescopique de caméra selon la revendication 1, caractérisée en ce que:

- la première extrémité (16) du premier tronçon (17) du câble entraînant est fixée à la flèche immobile (1), qui se trouve devant la première flèche mobile (2), pendant que la deuxième extrémité du premier tronçon (17) du câble entraînant est fixée au premier tambour de treuil (11);

- au premier tambour de treuil (11) est fixée aussi la première extrémité du deuxième tronçon (19) du câble entraînant, dont la deuxième extrémité (18) passe par la première poulie à câble (13) et est fixée à la deuxième flèche mobile (3);

- la première extrémité (20) du troisième tronçon (21) du câble entraînant est fixée à la deuxième flèche mobile (3), pendant que la deuxième extrémité du troisième tronçon (23) du câble entraînant est fixée au deuxième tambour de treuil (12);

- au deuxième tambour de treuil (12) est fixée aussi la première extrémité du quatrième tronçon (23) du câble entraînant, dont la deuxième extrémité (22) passe par la deuxième poulie à câble (14) et est fixée à la première flèche avant mobile (2).

3. Grue télescopique de caméra selon la revendication 1 ou 2, caractérisée en ce que les tambours de treuil (11, 12) d'un seul mécanisme entraînant le câble sont tenus sur un axe commun permettant la rotation (15), celui-ci étant fixé à la première flèche avant, mobile (2), l'axe indiqué ci-dessus (15) des tambours de treuil (11, 12) étant perpendiculaire à la direction du mouvement des flèches mobiles (2, 3, 4).

4. Grue télescopique de caméra selon l'une des revendications de 1 à 3, caractérisée en ce que le premier tronçon (17) et le deuxième tronçon (19) du câble entraînant d'un seul mécanisme d'entraînement, constituent deux parties du même câble ininterrompu.

5. Grue télescopique de caméra selon l'une des revendications de 1 à 3, caractérisée en ce que le troisième tronçon (21) et le quatrième tronçon (23) du câble entraînant d'un seul mécanisme d'entraînement, constituent deux parties du même câble ininterrompu.

6. Grue télescopique de caméra selon l'une des revendications de 1 à 5, caractérisée en ce que la première flèche mobile (2) est entraînée par une courroie crantée (26) qui passe parallèlement à l'axe longitudinal de la flèche immobile (1) et qui est tendue sur deux rouleaux dentés de renvoi (27), fixés à la flèche immobile (1).

Drawing