GB2540409A

GB2540409A - Camera mount

Info

Publication number: GB2540409A
Application number: GB1512464.7A
Authority: GB
Inventors: Arnold Le Poidevin Louis
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-07-16
Filing date: 2015-07-16
Publication date: 2017-01-18
Anticipated expiration: 2035-07-16
Also published as: GB201512464D0; GB2540409B

Abstract

A camera mount 2 comprising a rotatable connector 21 for connection to a camera. A motor 29 rotates the connector and a torque-limiting device (218, Figs 9 & 10) limits the torque transmittable between the motor and the camera. The torque limiter can act to protect the motor from excessive forces applied to the camera. The motor may be a stepper motor and the mount may comprise electronic circuitry 28 for controlling parameters such as the speed, direction and duration of the rotatable connector, these parameters may also be displayed on a LCD display 23. The torque limiting device may comprise a first component of plastics material which may be in an interference fit with a second component to transmit torque up to a predetermined limit, beyond which the components may slip against each other.

Description

CAMERA MOUNTS

The present invention relates to camera mounts and is concerned particularly with camera mounts that provide driven rotation of a mounted camera.

In the context of this specification, the term ‘camera’ includes any kind of imaging device, whether a dedicated camera or, for example, a smartphone or other device with imaging functionality.

Cameras are frequentiy mounted on tripods or other supports, in order to hold the camera steady whilst shots are taken. This is important for long-exposure shots, where motion of the camera will result in a blurred image. It is also important for motion picture shots, to provide a steady frame for the moving image.

Time lapse photography is very popular. Typically, a camera is programmed to take shots at intervals, which can be of any length and are often quite long. The images may later be viewed one at a time. However, when the shots are played back in sequence, without the inter-frame intervals, occurrences during the extended time of shooting are compressed into a much shorter viewing time, typically giving a motion picture effect.

If a camera is rotated slowly during time lapse photography, a panoramic moving image is created when the shots are played back in sequence, without the inter-frame intervals. This can be very effective, both from an aesthetic point of view and as a record of events occurring during the shooting period. Typically, a camera is rotated about a vertical axis but, in theory, rotation may be about any axis.

Camera mounts have been developed that provide rotational drive to a camera on the mount. See for example GB1038824. The speed and duration of the rotation are adjustable. The camera mount is typically supported on a tripod or other support, and affords a threaded stud that engages a threaded socket in the base of the camera.

It is desirable to provide a camera mount of such a type that is small, inexpensive, easy to program and able to support both small and large cameras reliably.

Preferred embodiments of the present invention aim to provide such camera mounts.

According to one aspect of the present invention, there is provided a camera mount comprising a rotatable connector for connection to a camera to support the camera on the camera mount, a motor for causing rotation of the connector and a torque-limiting device that is operative to limit the torque transmittable between the motor and a camera mounted on the connector.

Preferably, the camera mount further comprises a tripod connector for connection to a tripod or other support to support the camera mount on the tripod or other support.

Preferably, the camera mount further comprises a gearbox that is driven by the motor and has a drive shaft that is connected to the rotatable connector.

Preferably, the motor is a stepper motor.

Preferably, the camera mount further comprises electronic control circuitry for controlling the speed, direction and duration of rotation of the rotatable connector.

Preferably, the camera mount further comprises a display arranged to display selected parameters of speed, direction and/or duration of rotation of the rotatable connector and user controls for selecting different values of those parameters.

Preferably, the motor may be controlled to rotate at a slow speed for the purpose of time lapse photography.

Preferably, the motor and control circuitry therefor are powered by at least one battery housed in the camera mount.

Preferably, the camera mount has a substantially cylindrical housing in which components of the camera mount are housed.

Preferably, the camera mount further comprises a thumb wheel of generally flat, circular shape that acts as a lock nut for a camera when mounted on the rotatable connector.

Preferably, the torque-limiting device comprises a first component of plastics material that engages with a second component at an outer or inner circumferential surface of the first component as an interference fit, so as to transmit torque between the first and second components up to a predetermined limit, beyond which slip occurs between the first and second components.

Said second component may be the rotatable connector.

Said second component may be a drive shaft that is driven by the motor.

Preferably, said first component is an insert that engages within a hole in the rotatable connector; and a drive shaft that is driven by the motor engages within a hole in the insert.

Preferably, said first component is of acetal (polyoxymethylene).

The invention extends to a combination of a camera mount according to any of the preceding aspects of the invention and a camera mounted on the rotatable connector.

In another aspect, the invention extends to use of a combination as above in time lapse or video photography, wherein the camera is rotated by the rotatable connector as it captures a succession of discrete images or a continuous video image.

In another aspect, the invention provides a rotatable mount comprising a rotatable connector for connection to an item supported on the mount, a motor for causing rotation of the connector and a torque-limiting device that is operative to limit the torque transmittable between the motor and an item mounted on the connector.

Such a mount may further comprise one or more of the features disclosed in the present description, claims and/or drawings, in any combination.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which:

Figure 1 illustrates a camera mounted on a camera mount that is in turn mounted on a tripod;

Figure 2 illustrates a smartphone that incorporates a camera and is mounted on a camera mount that is in turn mounted on a tripod;

Figure 3 is a sectional view of a smartphone holder as used in Figure 2;

Figure 4 is an isometric view of one example of a camera mount, being one embodiment of the invention;

Figure 5 is a front view of the camera mount;

Figure 6 is a bottom view of the camera mount;

Figure 7 illustrates the layout of a liquid crystal display of the camera mount;

Figure 8 is a system block diagram of the camera mount;

Figures 9A to 9C 6 illustrate a novel drive shaft connector of the camera mount, respectively in side view, one end view and opposite end view; and

Figure 10 illustrates a plastics insert in longitudinal section.

In the figures, like references denote like or corresponding parts.

It is to be understood that the various features that are described in the following and/or illustrated in the drawings are preferred but not essential. Combinations of features described and/or illustrated are not considered to be the only possible combinations. Unless stated to the contrary, individual features may be omitted, varied or combined in different combinations, where practical.

Figure 1 illustrates in diagrammatic fashion a compact camera 1 that is mounted on a camera mount 2 that in turn is mounted on a tripod 3. The camera mount 2 is secured to the tripod by a standard threaded stud 31 that engages a correspondingly screw-threaded hole in the base of the camera mount 2. At its top, as seen, the camera mount 2 has a rotatable connector 21, with a standard screw-thread that engages a correspondingly screw-threaded hole in the base of the camera 1. The connector 21 is rotated by a motor within the camera mount 2.

Most tripods and camera mounts employ screw-threads of a standard size although, in principle, any sized screw-threads may be employed.

Figure 2 is generally similar to Figure 1, except that, in place of the camera 1, a smartphone 11 (or other electronic device) with a camera function is secured in a holder 12, being held between opposing side walls 121 on a base 122 having a screw-threaded hole 123 to engage with the connector 21, as shown in Figure 3. The smartphone 11 may be secured as a friction fit between the side walls 121, or means may be provided to clamp the side walls 121 together, with the smartphone 11 between them.

As shown in Figures 4 to 6, the camera mount 2 has a generally cylindrical housing 22, with the rotatable connector 21 located centrally at the top of the housing 22 and a screw-threaded hole 223 located centrally at the bottom of the housing 22 to engage with the threaded stud 31. An LCD display 23 is provided on a front face of the camera mount 2 and, below the display 23, push buttons 24, 25 and 26. One example of characters and icons that may be shown on the display 23 is shown in Figure 7 and will be described in further detail below.

The main components of the camera mount 2 are shown in the block drawing of Figure 8.

Batteries 27 supply power to a printed circuit board 28 on which a microprocessor is mounted and which supplies power and control signals to the LCD display 23 and a motor unit 29 that incorporates an electric motor and gearbox. A drive shaft 291 from the motor unit 29 engages the rotatable connector 21, to drive the connector 21 in rotation. An optional knurled thumb wheel 210, of a generally flat, circular shape, screw-threadedly engages the rotatable connector 21 to act as a lock nut when a camera 1 is mounted on the connector 21.

The rotatable connector 21 is shown in more detail in Figures 9A to 9C and an insert or bush 218 for the connector 21 is shown in Figure 10.

The connector 21 comprises a cylindrical base 211 that is formed with a circular hole 214 in which the insert 218 engages. The insert 218 is formed with a circular hole 219 in which the motor unit drive shaft 291 engages. The base 211 of the connector 21 has a chamfered portion 212 and extends into a threaded shaft 213 that, in use, engages the correspondingly threaded hole in the base of the camera 1.

The connector 21 may be machined as a single piece from stainless steel, apart from the insert 218, which may be of a plastics material such as, for example, acetal (polyoxymethylene). The insert 218 is press-fitted into the connector 21 as a tight interference fit within the hole 214; the acetal material of the insert 218 affording a slight amount of deformation. The motor unit drive shaft 291 is press-fitted into the insert 218 as a slightly less tight interference fit within the hole 219; the acetal material of the insert 218 again affording a slight amount of deformation.

The purpose of the acetal insert 218 is to limit the torque transmittable between the motor unit 29 and the camera 1 mounted on the connector 21.

This is unusual in a rotating camera mount, since the purpose of the camera mount is to rotate a camera slowly in very small steps, with accuracy. Providing slip in the camera drive would be seen as at variance with this. Indeed, limitation of drive torque is not the objective of this embodiment of the invention. On the contrary, this embodiment of the present invention has recognised a different problem in that, particularly with cameras of large mass (which can weigh of the order of 1 kg), there is a danger of causing damage to the motor unit 29, and particularly its gearbox, if the camera is engaged with the threaded shaft 213 and then rotated bodily to tighten up the fit between camera and shaft 213. Momentum of the relatively heavy camera, generated whilst the camera is being rotated, will be transmitted to the connector 21 as the camera becomes fully tightened upon the shaft 213 and, if no precautions are taken, that momentum will be transmitted as an impulse force to the relatively delicate motor unit 29 via its drive shaft 291. Damage to the motor unit 29, and particularly its gearbox, may therefore ensue.

In order to avoid such damage, the tightness of the interference fit between the acetal insert 218 and the motor unit drive shaft 291 is such as to allow slip for torques greater than a predetermined amount — for example, 1 kgcm (0.098 Nm). This may be sufficient to provide accurate drive under normal conditions, whilst protecting the motor unit from damage due to over-tightening of a camera on the connector shaft 213.

The interference fit between the acetal insert 218 and the connector 21 may provide less slip or none at all. Alternatively, it may provide the desired level of slip between the connector shaft 213 and the motor unit drive shaft 291, whilst the interference fit between the acetal insert 218 and the motor unit drive shaft 291 provides less slip or none at all. If the desired level of slip is provided at either one of the inner or outer circumferential surfaces of the acetal insert 218, the level of slip provided at the other of those surfaces does not matter too much, provided that it is greater.

Use of a plastics material such as, for example, acetal for the insert 218 is advantageous, as it is economical, has minimal expansion due to temperature and humidity and affords a small amount of deformation, to allow press fitting of the motor unit drive shaft 291 within the insert 218 and press fitting of the insert 218 into the connector 21. Also, acetal is a generally stable plastics material. However, other materials may be considered.

Other torque-limiting configurations may be considered. For example the drive shaft 291 may be formed with protrusions that engage corresponding detents within the hole 219, to lock the drive shaft 291 and insert 218 together until a limiting torque is reached, whereupon slip occurs. In a complementary arrangement, such protrusions and detents may be formed respectively on the insert 218 and drive shaft 291. A similar arrangement may be provided between insert 218 and connector 21. Mechanical features such as splines that engage complementary recesses, or interengaging shafts and holes of non-circular crosssection, may be provided at one of the inner and outer circumferential surfaces of the insert 218, to lock the insert 218 firmly to the drive shaft 291 or connector 21 for rotation.

In use, the camera mount 2 is secured to the tripod 3 by the threaded stud 31 and the camera 1 is secured to the camera mount 2 by the rotatable connector 21. Preferably, the flat thumb wheel 210 is used as a lock nut to secure the camera 1 in position and to provide a flat bearing surface against which the base of the camera 1 may bear.

The camera mount 2 is programmed via the push buttons 24, 25, 26 and LCD display 23. Push button 24 switches the camera mount on and off. Push button 25 advances user selection on the display 23. Push button 26 enters a user selection on the display 23.

As seen in Figure 7, the display 23 comprises five 7-segment indicators 231 that show numerical values for Flours Mins and Secs, the respective legends being positioned above the indicators 231. Three smaller 7-segment indicators 232 that show numerical values for either Turns or Degrees, the respective legends being positioned above and below the indicators 232.

At the bottom of the display 23, the legend ANTICLOCKWISE is shown, the prefix ANTI being selectable to indicate a choice of either clockwise or anticlockwise movement of the rotatable connector 21. A battery icon at the bottom right of the display 23 indicates battery status. To the left of the battery icon, a four-segment circular indicator 233 indicates rotation and direction, by sequential flashing of the segments; slow rotation of the connector 21 and camera 1 may be very difficult to detect visually. A pan icon 234 has three segments that indicate panning movement by sequential flashing of the segments; a solid single segment indicates a single pan. A wireless icon 235 indicates wireless connection to a remote programming device, which could be, for example, a smartphone or a dedicated controller.

The display 23 may be backlit and battery saving functions may be incorporated to switch off the backlight after a predetermined time, and to power down the camera mount 2 altogether if not used for a predetermined time.

By use of the push buttons 24, 25, 26, the user can select whether the rotatable connector should rotate continuously, the direction and speed of rotation and the total duration of the rotation or total number of turns. The user can alternatively select a panning rotation between selected limits expressed in degrees, along with speed of rotation and the total duration of the rotation or total number of turns (or pans).

Once the camera mount 2 has been programmed, the camera 1 mounted on it is rotated or panned according to the program. By way of example, the duration of a complete rotation or single pan can be set from 20 seconds to 9 hours, 99 mins and 99 secs. The device can be set to pan over a defined angle — for example, ranging from 15 to 360 degrees, set in 15 degree increments, back and forth.

By way of example, the camera mount 2 may be designed to rotate a camera weighing up to 1kg about a substantially vertical axis, or a camera weighing up to 250g at any angle. The motor used in the motor unit 29 may be a stepper motor, to afford rotation in precise steps. A stepper motor combined with an integrated spur gearbox may provide a useful drive. For example, a stepper motor with a step angle of 7.5° combined with a reduction gear having a ratio of 100:1 will provide a minimum rotational step si2e of 0.0075 degrees and a total of 4800 steps per revolution.

Although the preceding description refers primarily to use of the connector 21 with camera 1, it will be appreciated that it may apply equally to use of the holder 12 and smartphone 11 or other electronic device with camera function.

In a variant, a rotatable mount as illustrated in Figures 4 to 10 may be used to mount items other than cameras. Two examples are surveyors’ instruments and rotatable serving dishes. In each case, the torque-limiting components protect the motor from excessive torque being applied from the mounted item. With a suitable torque limit, a mounted item may be rotated manually at will by slipping with respect to the motor drive.

In this specification, terms of absolute orientation are used conveniently to denote the usual orientation of items in normal use and/or as shown in the accompanying drawings. However, such items could be disposed in other orientations, and in the context of this specification, terms of absolute orientation, such as "top", "bottom", "left", "right", "vertical" or "hori2ontal", etc are to be construed accordingly, to include such alternative orientations.

In this specification, the verb "comprise" has its normal dictionary meaning, to denote non-exclusive inclusion. That is, use of the word "comprise" (or any of its derivatives) to include one feature or more, does not exclude the possibility of also including further features. The word “preferable” (or any of its derivatives) indicates one feature or more that is preferred but not essential.

All or any of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all or any of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A camera mount comprising a rotatable connector for connection to a camera to support the camera on the camera mount, a motor for causing rotation of the connector and a torque-limiting device that is operative to limit the torque transmittable between the motor and a camera mounted on the connector.

2. A camera mount according to claim 1, further comprising a tripod connector for connection to a tripod or other support to support the camera mount on the tripod or other support.

3. A camera mount according to claim 1 or 2, further comprising a gearbox that is driven by the motor and has a drive shaft that is connected to the rotatable connector.

4. A camera mount according to claim 1, 2 or 3, wherein the motor is a stepper motor.

5. A camera mount according to any of the preceding claims, further comprising electronic control circuitry for controlling the speed, direction and duration of rotation of the rotatable connector.

6. A camera mount according to claim 5, further comprising a display arranged to display selected parameters of speed, direction and/or duration of rotation of the rotatable connector and user controls for selecting different values of those parameters.

7. A camera mount according to any of the preceding claims, wherein the motor may be controlled to rotate at a slow speed for the purpose of time lapse photography.

8. A camera mount according to any of the preceding claims, wherein the motor and control circuitry therefor are powered by at least one battery housed in the camera mount.

9. A camera mount according to any of the preceding claims, having a substantially cylindrical housing in which components of the camera mount are housed.

10. A camera mount according to any of the preceding claims, further comprising a thumb wheel of generally flat, circular shape that acts as a lock nut for a camera when mounted on the rotatable connector.

11. A camera mount according to any of the preceding claims, wherein the torque-limiting device comprises a first component of plastics material that engages with a second component at an outer or inner circumferential surface of the first component as an interference fit, so as to transmit torque between the first and second components up to a predetermined limit, beyond which slip occurs between the first and second components.

12. A camera mount according to claim 11, wherein said second component is the rotatable connector.

13. A camera mount according to claim 11, wherein said second component is a drive shaft that is driven by the motor.

14. A camera mount according to claim 11, 12 or 13, wherein said first component is an insert that engages within a hole in the rotatable connector; and a drive shaft that is driven by the motor engages within a hole in the insert.

15. A camera mount according to any of claims 11 to 14, wherein said first component is of acetal (polyoxymethylene).

16. A camera mount substantially as hereinbefore described with reference to the accompanying drawings.

17. In combination, a camera mount according to any of the preceding claims and a camera mounted on the rotatable connector.

18. Use of a combination according to claim 17 in time lapse or video photography, wherein the camera is rotated by the rotatable connector as it captures a succession of discrete images or a continuous video image.

19. A rotatable mount comprising a rotatable connector for connection to an item supported on the mount, a motor for causing rotation of the connector and a torque-limiting device that is operative to limit the torque transmittable between the motor and an item mounted on the connector.

20. A rotatable mount according to claim 19 and further comprising one or more of the features disclosed in the accompanying description, claims and/or drawings, in any combination.

21. A rotatable mount substantially as hereinbefore described with reference to Figures 4 to 10 of the accompanying drawings.