GB2128165A - Carriage for carrying a camera - Google Patents

Abstract

The invention relates to a camera carriage with a vertical lifting column for vertical adjustment of a camera. The column is telescopically extending and has a bottom outer part 10, a middle part 11 and an upper inner part 12. To allow frequent extending of the lifting column, the drive arrangement comprises a reversible electric motor 17 connected to the outer column part 10 for driving at least one endless chain 23, 24 which is guided parallel to the column axis over two end guide wheels 21, 22, 25, 26 between the intermediate and outer column parts 10, 11 and to one run of which the intermediate column part 11 is secured. To move the upper column part 12 there is at least one endless rope 43, 44 within the column parallel to its axis and which is guided over a pair of guide wheels 39, 40, 41, 42 on at least one wheel support 35, 36 extending into the column interior and connected to the intermediate column part 11. One run of the rope 43, 44 is connected to the upper, inner, column part 12 and the other run is connected to the upper end of a clamping bar 53, 54 secured on the bottom, outer, column part 10 and extending into the upper column part 12. <IMAGE>

Description

SPECIFICATION Carriage for carrying a camera The present invention relates to a carriage or truck for carrying a camera, the carriage having a telescopically extending column, with at least three parts, for raising and lowering the camera.

A camera carriage is known which has a three-part column, the middle column part constructed in the form of a cylinder, open at the bottom, into which projects a piston connected by way of a piston rod to the bottom column part. The piston and the piston rod are so constructed as to provide a supply ducting for a hydraulic medium. Associated with the camera carriage is a pressure medium storage means from which the hydraulic medium can be introduced into the cylinder (middle column part). This extends the middle column part relative to the bottom part. A chain is mounted on a rotatable element on the middle part, which chain is connected to the bottom and top parts of the column so that relative movement between the bottom part and the middle part causes the top part to move relative to the bottom part in the same direction as the middle part and twice as fast.The hydraulic medium is acted on pneumatically.

In this construction the number of possible lifting and lowering cycles is restricted by the pneumatic storage capacity of the pressure medium storage means and this has been found to be a disadvantage. The hydraulic drive involves considerable outlay and its size is increased by the necessity to take the control conduit with the control valve for the lifting operation into the immediate vicinity of the operator. Moreover the chain which ensures synchronous extending of the column parts and which forms the flexible traction element between the outer column part and the central column part is unavoidably exposed as the extending movement progresses, and is thus accessible to external influences.

Not only is it open to the risk of being soiled and damaged, but it is itself a possible source of accidents. It has also been found disadvantageous in the already known camera carriage that it would require a considerable, and therefore in actual practice prohibitive, increase in the dimensions of the triangularsection column parts if it were desired to lift and lower the cameraman along with the column.

By the present invention we seek to improve on the prior art carriage. According to the invention the middle column part is driven by an electric motor. The motor may be fixed to the bottom column part and drive imparted to the middle part by an endless band or chain. The band for raising and lowering the upper column part runs within the column.

Preferably there is a member of the bottom part which extends, when the column is retracted, within the middle and upper parts, and the band is fixed to this member and to the inside of the upper column part and is mounted on rotatable elements fixed to the inside of the middle part. The band is preferably an endless loop.

Even in the extended state of the column all the drive elements used for driving the middle column part, such as shafts, wheels, chains or ropes, are protected within the column parts, so that the risk of accidents is substantially eliminated. The use of the electric motor also allows effectively unlimitedly frequent extending and retracting of the column, using remote control if appropriate; even if a battery is used as the electric source, the number of possible lifting and lowering operations during use of the camera carriage is sufficient in practice.

Preferably the electric motor is reversible, and preferably the column parts are generally square in cross-section. The use of a reversible electric motor in conjunction with the square construction of the column parts also allows the column to take the additional load of the cameraman.

It is advantageous, from a constructional point of view, if a shaft associated with the electric motor extends transversely of the bottom column part at its lower end, the shaft having two wheels secured on it between the bottom and the middle column parts which wheels drive respective endless bands or chains to one run of each of which is secured the middle column part.

The load-bearing capacity of the column is increased if there are two endless bands to raise and lower the upper column part, each running on wheels mounted on supports common to the two bands, and two members of the bottom part extending within the middle and upper parts, each member secured to a run of a respective band.

Preferably the column parts are guided in their relative movement by guide wheels, which are mounted protected within the column between the column parts.

If the axes of the guide wheels are disposed parallel to the walls of the column parts, the diameter of the wheels depends on the spacing of the walls of neighbouring column parts.

Consequently the diameters of the wheels must necessarily be kept very small, which is disadvantageous. Transverse stresses in the extended column parts are transmitted via the wheels to those walls of the column parts which are themselves transverse to the direction of the stresses. To keep deformation of the walls to a low level, the walls have to be relatively thick.

We have realised that guide wheels of larger diameter, and a better bearing of stress by the walls, can be provided if the guide wheels are arranged with their axes transverse to the walls of the column parts, and guide strips are arranged on the walls of the column parts without wheels to interact with the guide wheels.

This construction is based on the realisation that the stresses of the walls of the column parts can be reduced, and wheels with a large diameter fitted into the narrow space left between the walls of adjacent column parts displaceable in one another, and satisfactory guiding can be ensured, if the wheels are swung round through 90 relative to the rest of the structure and they are made to cooperate with guide strips, which project transversely from the walls of the column parts. Conveniently the wheels are formed of running wheels in the form of ball bearings with strengthened race rings.

It has been found particularly advantageous from constructional and functional points of view to provide pairs of guide wheels and, associated with each pair of wheels, a guide strip which is engaged on both sides by the wheels.

To ensure satisfactory abutment of the wheels on the guide strip and thus reliable relative movement of the column parts in relation to one another, one of the two wheels in each pair could be displaceable towards the other wheel, and spring-loaded. In a simple constructional arrangement, which provides a secure abutment of the wheels and the guide strip without the need for a displaceable spring-loaded wheel, the axes of the wheels of a wheel pair converge on each other at a very small angle of about 1 in the non-loaded state. In this way, when the guide strip is inserted into the gap between the two wheels there is a very small elastic deformation of the wheel shafts or the wall of the column part on which the shafts are secured. In has been found that this elastic deformation is sufficient to ensure the required abutment.

Embodiments of the present invention, given by way of example, will now be described with reference to the accompanying drawings in which: Figure 1 is a side view of a camera carriage embodying the invention with the lifting column in the lowered and in the lifted positions, Figure 2 shows a vertical section through the bottom column part of the lifting column, with attached electric motor, Figure 3 shows a vertical section through the middle and upper column parts of the lifting column, Figure 4 shows a section view taken on the line IV-IV of Fig. 3, Figure 5 shows a section through the upper column part taken on the line V-V of Fig. 3, Figure 6 shows a vertical section taken on the line VI-VI of Fig. 3, and Figure 7 shows a horizontal section through one half of the lifting column of a modified constructional form.

A camera carriage (Fig. 1) has a chassis with supporting arms 3, 4 pivotable about vertical shafts 1, 2. On the ends of the arms 3, 4 there are bearings for wheel pairs 7, 8 slewable about shafts 5, 6. An important part of the camera carriage is the vertical lifting column 9 which serves for vertical adjustment of the camera (not shown). It has an outer, bottom, column part 10 resting on the chassis, an intermediate column part adapted to be extended out of the bottom column part in telescopic manner, and a central, upper, column part 1 2 adapted to be extended from the intermediate column part 11. Rotatably mounted on the upper end of the upper column part 1 2 is a projecting arm 1 3 on which a camera can be secured.On the outer end of the arm 1 3 there is a supporting pivot 14 with a supporting arm 1 5 for a seat 1 6 for a cameraman. The cameraman can thus be lifted and lowered with the camera, and this greatly facilitates his camera work. If there is associated with the supporting pivot 14 a relatively long pivot pin it becomes possible to adjust the height of the supporting arm 1 5 and thus the height of the seat 1 6 in relation to the arm 1 3, and thus to adapt to the type of camera.

A reversible electric motor 1 7 (Fig. 2) is secured on the outer side of the outer column part 10, with its axis parallel to that of the column. Coaxial with the electric motor 1 7 is a planetary reduction gearing 1 8 which is not shown in detail and on the far side of that is a bevel gearing 1 9. By means of the bevel gearing 1 9 it is possible to drive a shaft 20 which extends transversely through the outer column part 10 at its lower end adjacent the chassis. Pinions 21, 22 are secured on the shaft 20 in each case between the outer column part 10 and the intermediate column part 11 (which is only shown in chain-dotted lines in Fig. 2). The pinions each drive a respective endless chain 23, 24. Each chain 23, 24 runs on a respective end guide wheel 25, 56 mounted on the inside of the wall of the outer column part. The pinions 21, 22 and the end guide wheels 25, 26 hold the chains 23, 24 between them in courses parallel to the axis of the column. The upper guide wheels 25, 26 are vertically adjustable on the wall of the outer column part 10, to allow for tensioning of the chains 23, 24. The intermediate column part 11 is secured to one run of each of the chains 23, 24 by means of clamping devices 27, 28 bolted to it. When the shaft 20 rotates in one direction the middle column part 11 is lifted and extended by means of the clamping devices 27, 28.To ensure that the clamping devices 27, 28 do not come into contact with the upper guide wheels 25, 26 there is secured on the shaft 20 an additional pinion 29 by means of which, in a manner not shown in detail; a cam connected to a chain can be moved for controlling a limit switch which is also not shown.

It is advantageous to provide the column with a spring which is loaded by retraction of the column 9 and unloaded by extension of the column 9. This relieves the electric motor 1 7 of a substantial part of the load so that, for example, it is substantially only loaded with the weight of the cameraman.The spring could be a spiral spring of relatively long spring travel associated with the shaft 20 and located, for example, in the region of the pinion 29.

Figs. 3 and 4 show the construction of the middle and upper column parts 11, 1 2. As can be seen from Fig. 4, all three column parts 10, 11, 1 2 are of substantially square cross-section. Three wheels 30 are fixed one below another on the inside of each of the four walls of the intermediate column part 11, the upper, central, column part 1 2 being guided on these wheels against which the outer surface of its walls abuts. The upper portion of Fig. 6 shows the arrangement of these wheels 30 in bearing blocks 31 in more detail. In a similar way a plurality of wheels are also fixed to the inside of each of the four wheels of the bottom, outer, column part 10, on which wheels the intermediate column part 11 is guided by abutment with the outsides of its walls.However, unlike the arrangement in Fig. 6, bearing blocks for the wheels guiding the intermediate column part 11 are divided vertically and arranged in pairs spaced from one another, so that between them there is space for the endless chains 23, 24.

Preferably all the wheels 30 have a relatively large diameter, e.g. of at least 25 mm.

This-as tests have shown-ensures running with very little noise when the column is extended and retracted, apparently due to the low speed of rotation. Both the middle column part 11 and the upper column part 1 2 are provided at their lower ends with apertures 32, 33 (Fig. 3), through which the shaft 20 extends when the column parts are lowered. A bridge 34 is disposed above the shaft 20 between the two walls of the middle column part 11 parallel with the shaft 20 (Figs. 3 and 4). The bridge is bolted to the middle column part 11 at each end (Fig. 4). Extending upwards from this bridge 34 are two wheel supports 35, 36 arranged symmetrically about the axis of the column. These supports 35, 36 extend within the upper, central, column part 1 2 substantially to its upper end when the column is retracted.Secured on these wheel supports 35, 36 are shafts 37, 38 which extend through the supports and on which are mounted two pairs of guide wheels 39, 40, 41, 42. An endless band or rope 43, 44 runs on each pair of guide wheels. The ropes 43, 44 are disposed parallel to the axis of the column. To tension the ropes there are associated with the lower wheels 40, 41 respective tensioning devices 45, 46 (Figs. 3 and 6) which are each attached to a respective end of the shaft 38 and by way of a screw 47, 48 to the underside of the bridge 34. To provide improved stability the two wheel supports 35, 36 are connected to one another by means of additional members 49, 50.

Two supporting arms 51, 52 are fixed by screw means such as bolts to the inside of the bottom, outer, column part 1 0 (Fig. 4). The arms 51, 52 extend inwardly of the column, transversely to the shaft 20. They are used for fixing two clamping bars 53, 54 which run upwards within the upper, central, column part 1 2 through apertures in the bridge 34 which are not shown in the drawings.The upper ends of the clamping bars 53, 54 are each connected to one run of a respective endless rope 43, 44. For this purpose the clamping bars each terminate in a lateral projection 55 (Fig. 3) with a slot-shaped opening 56. As Fig. 5 shows, a plate-shaped holding element 57 extends between the two clamping bars 53, 54 and over their end faces. The element 57 is bolted to the clamping bars 53, 54 at their end faces.It extends over the projections 55 and has corresponding slot-shaped openings 58. The slot-shaped openings 56, 58, the width of which is adapted to the thickness of the ropes 43 and 44 allow insertion of the ropes sideways, and in each case a clamping sleeve 59, 60 (Fig.

3) on each rope 43, 44 is inserted between the projection 55 and the plate-shaped holding element 57, in the region of the slotshaped openings 56 and 58.

Immediately above the lower guide wheels 40, 41 the other runs of the rope 43, 44 are secured to the inside of the upper, central, column part 1 2. For this purpose clamping sleeves 61, 62 are also connected to the rope. Associated with each rope is a holding shoe 63 which is adjustably secured by bolts to the lower end of the upper column part 1 2.

At the upper end of the shoe 63 there is a lateral projection 64 with a slot-shaped opening 65. A holding plate 66 is screwed down on the upper end face of the holding shoe 63 and has a similar slot-shaped opening 67. The slot-shaped openings 65, 67 allow introduction of the relevant draw rope 44 sideways, and they are positioned so that the clamping sleeves 61, 62 can be fitted between the projection 64 and the holding plate 66 in the region of the slot-shaped openings 65, 67.

The lifting column described above operates as follows: When the middle column part 11 is extended out of the bottom column part 10 the guide wheels 39, 40, 41, 42 are carried with it by the wheel supports 35, 36. Thus these guide wheels move relative to the clamping bars 53, 54, to the upper ends of which the ropes 43, 44 are connected. Therefore, as the middle column part 11 moves upwards the parts of the ropes 43, 44 clamped to the bars 53, 54 remain substantially stationary. Consequently the ropes move over the guide wheels and the runs not clamped to the bars travel upwards at double speed relative to the speed of the extension of the middle column part.

These moving runs include the parts clamped to the upper column part 1 2 via the clamping sleeves 61, 62 and the upper end of the holding shoes 63. Therefore the upper column part 1 2 is extended at double the speed of the middle column part 11. When the middle column part 11 is lowered relative to the bottom column part 10, the ropes 43, 44 move over the guide wheels 39, 40, 41, 42 in the opposite direction, and the upper column part 1 2 returns to the initial position, shown in Fig. 3.

The electric motor 1 7 can be supplied with current from a battery or via a cable. In the latter case remote control by means of a control switch situated within reach of the cameraman is also possible. Alternatively there can be cordless remote control of the electric drive, for example by wireless or by means of an ultrasonic transmitter with a receiver associated with the electric motor.

Fig. 3 shows that the upper column part 1 2 is connected to a cylindrical mount 68 for the camera, which is not shown in detail. This mount 68 is part of the arm 1 3 which is pivotable about the axis of the column (see Figs. 1 and 6). The upper column part 12 has a bearing pin 69 on which the arm 1 3 is mounted by the mount 68 in such a manner as to be rotatable on a rolling contact bearing 70. Below the bearing pin 69 a coaxial disc 71 is also connected securely to the upper column part 1 2. A swing brake 72, which comes into action when the arm 1 3 is swung round, acts on this disc 71 (Fig. 6).It is also advantageous to provide an arresting device with a screw or the like acting directly on the disc edge, hand operated by way of a rotary handle, so that the device can hold the arm 1 3 in the particular rotational position desired at any one time.

In a modified constructional form shown in Fig. 7, the upper column part 1 2 has four walls 73 connected to one another by screwed connections. The intermediate column part 11 also comprises four walls 74 connected to one another by screwed connections. The outer, bottom, column part 10 also comprises four walls 75, but these are connected to one another not directly but by way of intermediate elements 76. On the inner sides of walls 74, 75 of the intermediate and outer column parts 11, 10 respective pairs of wheels 77, 78 are mounted to be rotatable about journals 79, 80, which journals extend transverse to these walls. These wheels 77, 78 take the form of ball bearings with reinforced race rings. There is associated with each pair of wheels 77, 78 a respective guide strip 81, 82 engaged on both sides by the wheels.The guide strips 81, 82 extend parallel to the column axis and project transversely from the outer side of the respective adjacent column part 11, 12. Each guide strip 81, 82 is attached to the relevant wall 73, 74 by screw means, and the walls 73, 74 have grooves 83, 84 for receiving one edge of the guide strips 81, 82. The strips are positioned half-way across the width of each wall.

In a manner which is not shown in Fig. 7 the journals 79 and 80 of the wheels of each pair of wheels are not parallel to one another.

They converge very slightly towards their free ends at an angle of about 1 in the nonloaded state. On introduction of the guide strip 81, 82 into the gap between the wheels 77, 78 of the relevant pair. there is a very small elastic deformation of the wheel journals 79, 80 and also of the wall 74. 75 on which the journals are secured. This elastic deformation ensures the requisite guiding abutment between the wheel and the associated guide strips when the column is retracted and extended.

Claims (25)

1. A carriage for carrying a camera, the carriage having a telescopically extending column, with at least three parts, for raising and lowering a camera carried by the carriage, the column having a first, outer, bottom part, a second, middle, part and a third, inner, upper part, the carriage having an electric motor to raise the middle part relative to the bottom part and a flexible band for moving the upper part relative to the bottom and middle parts when the bottom and middle parts are moved relative to each other, the flexible band extending within the column.

2. A carriage according to claim 1 in which the said flexible band is mounted on rotatable elements fixed to the middle column part, the band being fixed to the inside of the upper column part and to a member of the bottom column part which extends, when the column is retracted, within the middle and upper column parts, the flexible band running within the upper column part when the column is retracted.

3. A carriage according to claim 2 in which the said flexible band is a closed loop, and extends parallel to the axis of the column, the said rotatable elements comprising at least two wheels spaced axially from each other and mounted on a wheel support, which wheel support extends within the upper column part when the column is retracted and is secured to and moves with the middle column part.

4. A carriage according to claim 3 in which there are two said flexible bands, dis posed symmetrically about the axis of the column, each band being mounted on respective wheels on respective said wheel supports disposed symmetrically about the axis of the column, and each band being fixed to respective said members of the bottom column part disposed symmetrically about the axis of the column.

5. A carriage according to any one of the preceding claims in which the said bottom, middle and upper column parts are of substantially square section.

6. A carriage according to any one of the preceding claims in which the electric motor drives a second endless band which extends parallel to the column axis, movement of the second endless band causing relative movement between the said bottom and middle column parts.

7. A carriage according to claim 6 in which the second endless band is mounted on wheels rotatably fixed to the bottom column part and disposed radially (of the column) between the bottom and middle column parts, the middle column part being secured to one run of the second endless band.

8. A carriage according to claim 7 in which the lower said wheel on which the second endless band is mounted, is fixed to the bottom column part via a shaft on which it is mounted and with which it turns so that rotation of the shaft drives the second endless band and moves the middle column part relative to the bottom column part, the shaft being driven by the electric motor and extending transversely of the bottom column part at its lower end.

9. A carriage according to claim 8 in which the second endless band is a chain and the said wheel on the shaft is a sprocket wheel.

10. A carriage according to claim 8 or claim 9 in which the shaft extends across substantially the whole width of the bottom column part and in which there are two said second endless bands, one on each side of the middle column part, each mounted on a respective said wheel on the shaft, the middle column part being secured to one run of each said second endless band.

11. A carriage according to any one of claims 8 to 10 in which the elctric motor is mounted on the outside of the column, with its axis parallel to the column axis, and drives the shaft via bevel gearing.

1 2. A carriage according to claim 11 in which there is reduction gearing between the electric motor and the bevel gearing.

1 3. A carriage according to any one of the preceding claims in which the column parts, when they move relative to each other, run on guide wheels disposed between them.

1 4. A carriage according to claim 1 3 in which the guide wheels are disposed in groups, the wheels of a group being axially spaced from each other.

1 5. A carriage according to claim 1 3 or claim 14 in which the or some of the guide wheels between two of the column parts are mounted for rotation on journals arranged transverse to the walls of the column parts, the journals being disposed on the walls of one of the column parts and guide strips being disposed on the other of the column parts which guide strips are engaged by the guide wheels.

16. A carriage according to claim 1 5 in which the guide wheels mounted on the said journals have a diameter greater than the spacing between the two column parts.

1 7. A carriage according to claim 1 5 or claim 1 6 in which the guide strips are engaged by guide wheels on both sides.

18. A carriage according to claim 17 in which the journals of the guide wheels on one side of each strip are spring-loaded, so that the guide strip is gripped between the wheels on each side of it.

1 9. A carriage according to claim 1 7 in which the journals of the pairs of guide wheels on either side of each guide strip converge when they are not loaded, the presence of the guide strip being the wheels pushing them apart so that it is gripped between them.

20. A carriage according to any one of claims 1 5 to 1 9 in which the column parts are flat-walled, and the guide strips are disposed midway across the width of the walls.

21. A carriage according to any one of the preceding claims in which the upper column part carries a mount for carrying a camera.

22. A carriage according to claim 21 in which the mount is connected to or is a part of an arm extending sideways from the upper column part and which is rotatable about the column axis, the end of the arm remote from the column having a joint for the pivotal connection of a seat for a cameraman.

23. A carriage according to claim 22 in which the arm has a brake which engages a disc co-axial with the column, to brake the said rotational movement of the arm.

24. A carriage according to claim 23 in which the arm also has a manually operable screw device which can be screwed up against the disc to lock the arm in position.

25. A carriage for carrying a camera substantially as herein described with reference to and as illustrated in the accompanying drawings.