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Title:
APPARATUS FOR APPLYING A COUNTERBALANCE TORQUE TO A TRIPOD HEAD
Document Type and Number:
WIPO Patent Application WO/2017/177282
Kind Code:
A1
Abstract:
The present invention discloses an apparatus (10) for applying a counterbalance torque to a tripod head (12). The apparatus includes a housing (14), and a shaft (16) disposed within the housing. Two or more primary torsion springs (20) and at least one secondary torsion spring (22) are generally located within the housing (14). A primary control device (24) is provided on a primary side (26) of the housing to selectively engage each of the primary torsion springs (20), thereby to apply a primary counterbalance torque to the shaft. Similarly, a secondary control device (28) is provided on a secondary side (30) of the housing to selectively engage the secondary torsion spring (22) and apply a secondary counterbalance torque to the shaft.

Inventors:
ABELEV MICHAEL (AU)
BARNES ANDREW (AU)
Application Number:
PCT/AU2017/050338
Publication Date:
October 19, 2017
Filing Date:
April 13, 2017
Export Citation:
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Assignee:
CLEMSEVEN HOLDINGS PTY LTD (AU)
International Classes:
F16M11/10; F16F1/14; F16F3/00
Foreign References:
US20080258022A12008-10-23
US4447033A1984-05-08
US20110084188A12011-04-14
US4959671A1990-09-25
Other References:
VIDEO 18 SI FLUID HEAD MANUAL, 2 July 2015 (2015-07-02), Retrieved from the Internet [retrieved on 20170711]
Attorney, Agent or Firm:
SHELSTON IP PTY LTD (AU)
Download PDF:
Claims:
CLAIMS

1 . An apparatus for applying a counterbalance torque to a tripod head, said apparatus including:

a housing;

a shaft disposed within said housing;

two or more primary torsion springs and at least one secondary torsion spring, said primary and secondary torsion springs being generally disposed within said housing;

a primary control device for selectively engaging each of said two or more primary torsion springs thereby applying a primary counterbalance torque to said shaft, said primary control device being disposed on a primary side of said housing; and

a secondary control device for selectively engaging said at least one secondary torsion spring thereby applying a secondary counterbalance torque to said shaft, said secondary control device being disposed on a secondary side of said housing,

wherein upon selective application of said primary and secondary control devices a predetermined counterbalance torque is applied to said shaft.

2. An apparatus according to claim 1 , wherein said two or more primary torsion springs include three primary torsion springs.

3. An apparatus according to claim 1 or claim 2, wherein said at least one secondary torsion spring includes one secondary torsion spring.

4. An apparatus according to any one of claims 1 to 3, wherein at least one of said primary and secondary torsion springs includes a resilient elastomeric spring element.

5. An apparatus according to any one of the preceding claims, wherein the spring torque provided by the secondary torsion spring is less than the spring torque provided by any one of the primary torsion springs.

6. An apparatus according to any one of the preceding claims, wherein the spring torque provided by the secondary torsion spring is at least half the spring torque of any one of the primary torsion springs.

7. An apparatus according to any one of the preceding claims, wherein said primary control device includes two or more pins slidingly engagable with complementary bores in said primary side of said housing.

8. An apparatus according to any one of the preceding claims, wherein said primary control device includes three pins.

9. An apparatus according to claim 7 or 8, wherein said pins are axially moveable with respect to said housing to engage the periphery of each of said primary torsion springs thereby selectively restricting the relative rotation of the outside portion of each of said primary torsion springs.

10. An apparatus according to claim 9, wherein upon selectively restricting the relative rotation of the outside portion of each of said primary torsion springs, a primary

counterbalance torque is applied to said shaft.

1 1 . An apparatus according to any one of claims 7 to 10, wherein each of said pins is resiliently biased away from the periphery of said two or more primary torsion springs.

12. An apparatus according to any one of the preceding claims, wherein said primary control device includes a rotary control member having at least two annular cam surfaces for applying a selective lateral force to each of said pins in accordance with a predetermined angular position.

13. An apparatus according to any one of the preceding claims, wherein said secondary control device includes a two stage rotary switch rotatable between an engaged configuration and an unengaged configuration.

14. An apparatus according to any one of the preceding claims, wherein when said secondary control device is in said engaged configuration the periphery of said secondary torsion spring is locked with respect to said housing.

15. An apparatus according to any one of the preceding claims, wherein when said secondary control device is in the unengaged configuration the periphery of said secondary torsion spring is substantially free to rotate with said shaft.

16. An apparatus according to any one of the preceding claims, wherein when said secondary control device is in said engaged configuration, said secondary torsion spring applies said secondary counterbalance torque to said shaft. An apparatus according to any one of the preceding claims including a fixed torsion

Description:
APPARATUS FOR APPLYING A COUNTERBALANCE TORQUE TO A TRIPOD

HEAD

TECHNICAL FIELD

[0001 ] The present invention relates to tripod heads and in particular to an apparatus for applying and controlling counterbalance torque to a tripod head.

[0002] The invention has been developed primarily as an apparatus for counterbalancing a load carried by the tripod. However, it will be appreciated that the invention is not limited to this particular field of use.

BACKGROUND

[0003] The following discussion of the prior art is intended to place the invention in an appropriate technical context and enable the associated advantages to be fully understood. However, any discussion of the prior art throughout the specification should not be considered as an admission that such art is widely known or forms part of the common general knowledge in the field.

[0004] Professional tripod heads often employ counterbalance systems to retain a supported camera, or other equipment, at a desired tilted position. To achieve this functionality, these counterbalance systems normally include a series of springs, which resist forward and rearward rotation or tilt of the tripod head.

[0005] Using such arrangements, it is known that if the spring resistance is too high, the camera will move back to the horizontal position. Conversely, if the spring resistance is too low, the camera will tilt down towards a vertical position. Therefore, in order to hold the camera at a desired tilted position without user assistance, an ideal biasing force against rotation of the camera is required.

[0006] One known system for providing rotational resistance includes a plurality of springs which are selectively engaged by the user. The springs are encased in the tripod head and act against rotation of the tripod head. Progressive spring engagement is usually provided by rotation of a counterbalance dial allowing a user to simply achieve the degree of rotational spring resistance required. In other known systems, rotational spring resistance may be adjusted by some form of slider control, however, the principals of progressively engaging more and more springs, is essentially the same.

[0007] A problem with these types of systems is that in order to provide a finer range of rotational spring resistance, more springs need to be added to the tripod head casing. These additional springs fill in any load gaps between the existing springs to allow a user to select an appropriate counterbalance torque. The concern with adding more springs however, is that in order to provide a level of convenient control, an overly complex selection device is required, which in turn, presents difficulties in packaging the tripod head. Moreover, complex control systems can make the tripod head overly heavy, cumbersome, and expensive to manufacture.

[0008] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0009] In at least one preferred form, it is an object of the invention to provide an apparatus for selection of a greater number of selectable values within the available range of counterbalance torque applied to a tripod head without making it overly cumbersome or heavy.

SUMMARY OF THE INVENTION

[0010] The present invention provides an apparatus for applying a counterbalance torque to a tripod head, the apparatus including:

a housing;

a shaft disposed within the housing;

two or more primary torsion springs and at least one secondary torsion spring, the primary and secondary torsion springs being generally disposed within the housing;

a primary control device for selectively engaging each of the two or more primary torsion springs thereby applying a primary counterbalance torque to the shaft, the primary control device being disposed on a primary side of the housing; and

a secondary control device for selectively engaging the at least one secondary torsion spring thereby applying a secondary counterbalance torque to the shaft, the secondary control device being disposed on a secondary side of the housing,

wherein upon selective application of the primary and secondary control devices a predetermined counterbalance torque is applied to the shaft. [001 1 ] In one embodiment, the two or more primary torsion springs include three primary torsion springs.

[0012] In one embodiment, the at least one secondary torsion spring includes one secondary torsion spring.

[0013] In one embodiment, at least one of the primary and secondary torsion springs includes a resilient elastomeric sprint element. In one embodiment, each of the primary and secondary torsion springs includes a resilient elastomeric spring element.

[0014] In one embodiment, the spring torque provided by the secondary torsion spring is less than the spring torque provided by any one of the primary torsion springs.

[0015] In one embodiment, the spring torque provided by the secondary torsion spring is at least half the spring torque of any one of the primary torsion springs.

[0016] In one embodiment, the primary control device includes two or more pins slidingly engagable with complementary bores on the primary side of the housing.

[0017] In one embodiment, the primary control device includes three pins.

[0018] In one embodiment, the pins are axially moveable with respect to the housing to engage the periphery of each of the primary torsion springs thereby selectively restricting the relative rotation of the outside portion of each of the primary torsion springs.

[0019] In one embodiment, upon selectively restricting the relative rotation of the outside portion of each of the primary torsion springs, a primary counterbalance torque is applied to the shaft.

[0020] In one embodiment, each of the pins is resiliently biased away from the periphery of the two or more primary torsion springs.

[0021 ] In one embodiment, the primary control device includes a rotary control member having at least two annular cam surfaces for applying a selective lateral force to each of the pins in accordance with a predetermined angular position. [0022] In one embodiment, the secondary control device includes a two stage rotary switch rotatable between an engaged configuration and an unengaged configuration.

[0023] In one embodiment, when the secondary control device is in the engaged configuration, the periphery of the secondary torsion spring is locked with respect to the housing.

[0024] In one embodiment, when the secondary control device is in the unengaged configuration, the periphery of the secondary torsion spring is substantially free to rotate with the shaft.

[0025] In one embodiment, when the secondary control device is in the engaged configuration, the secondary torsion spring applies the secondary counterbalance torque to the shaft.

[0026] In one embodiment, the apparatus further includes a fixed torsion spring.

[0027] Reference throughout this specification to "one embodiment", "some embodiments" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment", "in some embodiments" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] One or more preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0029] Figure 1 is a front view of a tripod head in accordance with one embodiment of the invention;

[0030] Figure 2 is an exploded and part cut away perspective view of the tripod head of Figure 1 ; [0031 ] Figure 3 is an exploded and part cut away perspective view of the primary and secondary control devices of the tripod head of Figure 1 ;

[0032] Figure 4 is a perspective view of the primary and secondary control devices of the tripod head of Figure 1 ;

[0033] Figure 5 shows side and end views of components of the secondary control device;

[0034] Figure 6 is an enlarged view of the primary and secondary control device selection dials showing the method of use of the present invention;

[0035] Figure 7 is a side view of a tripod head in accordance with a further embodiment of the invention;

[0036] Figure 8 is a section view along line 8-8 of the tripod head of Figure 7; and [0037] Figure 9 is a section view along line 9-9 of the tripod head of Figure 7. DESCRIPTION OF PREFERRED EMBODIMENTS

[0038] Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals throughout. In the following description, detailed descriptions of known functions and configurations incorporated herein have been omitted for conciseness and clarity.

[0039] Referring to the accompanying the drawings and initially to Figure 1 , there is provided a tripod head 12 employing an apparatus 10 for applying a counterbalance force against rotation of an object on tripod. Without wishing to limit the invention to one particular use, it is proposed that apparatus 10 be used to apply a counterbalance force against rotation or torque to a tripod head 1 , so as to counterbalance the load provided by a camera mounted thereon.

[0040] With reference to the part cut away perspective view shown in Figure 2, the apparatus includes housing 14 and a main rotational shaft 16, which is supported by roller bearings 18 mounted within the housing. Two or more primary torsion springs 20 and at least one secondary torsion spring 22 are generally located within the housing 14 so as to provide the counterbalance torque. In the embodiment depicted in Figure 2, three primary torsion springs 20 and one secondary torsion spring 22 are provided. However, in other not shown embodiments, more secondary torsion springs may be used without departing from the scope of the invention. As can be seen, both the primary and secondary torsion springs are supported by shaft 16.

[0041 ] A primary control device 24 is provided on a primary side 26 of the housing 14 to selectively engage each of the primary torsion springs 20 thereby applying the primary counterbalance torque to the shaft 16. Similarly, to engage the single secondary torsion spring 22 and apply a secondary counterbalance torque to the shaft 16, a secondary control device 28 is provided on a secondary side 30 of the housing. The arrangement is such that upon selective application of the primary and/or secondary control devices a predetermined counterbalance torque is applied to the shaft 16.

[0042] The shaft 16 is in direct coupled engagement with end plates 32, which support a top plate 34 via a fastening means as known in the art. Top plate 34 is then used as the main support for a camera or other device that requires a counterbalance torque applied by the shaft 16, so as to counteract rotational momentum provided by the weight of the camera or other device.

[0043] With additional reference to Figures 3 and 4, each circular primary torsion spring 20 includes a resilient elastomeric spring element 36 surrounding a solid boss 38. The solid boss includes keyway 40 for keyed engagement with shaft 16 via a complimentary key. To complete each primary torsion spring, a solid circular peripheral ring 42 is provided.

[0044] As described in more detail below, a radially extending circular peripheral bore 44 is located on each ring's outer surface for engagement by the primary control device 24.

[0045] Referring now to Figures 3 to 5, the secondary torsion spring 22 similarly includes an elastomeric spring element 46 surrounding a secondary solid boss 48 and solid circular outer ring 50. The solid boss includes a keyway 41 for keyed engagement with the shaft 16 in a similar way to the primary torsion spring. However, differing from the primary torsion spring, the secondary torsion spring 22 includes an axially extending slot 54 in the outer circular ring 50 for engagement with the secondary control device 28 as described in more detail below. [0046] In the illustrated embodiments, the bosses and circular outer rings are made from aluminium and the elastomeric spring elements are formed from rubber specified to provide known elastic resistance and therefore a predetermined spring torque. With this in mind, it should be appreciated that according to the invention the spring torque provided by the secondary torsion spring is less than the spring torque provided by any one of the primary torque springs. In the illustrated embodiment, the spring torque provided by the secondary torsion spring is at least half the spring torque of any one of the primary torque springs. Further, in the illustrated embodiment it is proposed that the resilient torque provided by each primary torsion spring is equal.

[0047] The primary control device 24 includes two or more pins 56 slidingly axially moveable and guided within complementary bores 45 in the primary side of the housing 14. In the illustrated embodiment, three pins 56 are provided for corresponding and selective engagement with the peripheral bores 44 in each of the primary torsion springs 20. Upon engagement of each peripheral bore 44 the outside portion of the respective primary torsion spring is locked in position with respect to housing 14. Consequently, a primary resistive and elastic torque is applied to the shaft.

[0048] As shown, pin followers 58, which are respectively attached to each pin 56, are in contact with an annular cam ring 66. Annular cam ring 66 is made up of a plurality of discrete raised portions 62 and flat portions 64 to selectively push on the pin followers 58 thereby selectively axially displacing each pin. These components are retained in respective locations by way of controller housing 60. The cam ring 66 is also housed within a primary dial 68 to allow selective rotation by the user. In this respect, upon rotation of the primary dial 68, each pin is exposed to either a raised portion or flat portion thereby respectively defining an engaged or disengaged position. In the engaged position, the pin is axially displaced, within the complementary bores in the housing 14, to engage with the peripheral bore 44 of a respective primary torsion spring 20. Conversely, in the disengaged position, the pin is moved out of the peripheral bore of the primary torsion spring. To facilitate the latter action, coil springs 70 are provided around one end of each pin 56 thereby biasing each pin away from the primary torsion springs and maintain contact with the cam ring.

[0049] It can be seen that by using this arrangement one or all of the pins 56 may be in the engaged position. Indeed, using three pins as in the illustrated embodiment, it can be seen that eight possible configurations of engagement, ranging from zero primary torsion spring engagement to all of the primary torsion springs being engaged. Consequently, eight individual values of primary torque resistance would be available using the illustrated embodiment ranging upwards from zero torque. Moreover, since it is proposed that each primary spring provide equal counterbalance torque, each of the torque values provided are equally and progressively spaced.

[0050] It is proposed that each of these eight configurations be selected by stepped rotation of primary dial 68. Further, the discrete raised portions 62 and flat portions 64 are arranged on the cam ring such that sequential rotation of the primary dial 68 in a first direction will result in a progressively increasing primary torque resistance by selective engagement of the three primary torsion springs. Similarly, rotation in an opposite direction will result in a progressively decreasing primary torque resistance. To this end and as described in more detail below, primary dial 68 includes a rotary scale 72 with each configuration indicated by an increasing numbered value. It will be further appreciated that upon each stepped rotation to the next numeric value, one or more pins will move from the engaged to disengaged position resulting in a 'click' sound upon each stepped rotation.

[0051 ] It should be understood that if a fourth primary torsion spring was added to provide a further level of torque to the primary counterbalance torque, the above mentioned primary control device would not be able to operate in the same manner. That is, a completely different method of engaging the outer periphery of each spring would be required. For example, to provide primary torque selection device using a dial and four torsion springs a much more elaborate, complex and cumbersome selection device would be required. Accordingly, in order to circumvent this complication and according to the present invention a secondary control device is provided.

[0052] Returning to Figures 3 to 5, the present invention includes a secondary control device 28 having a stub shaft 74 located in the secondary side 30 of housing 14. Stub shaft 74 includes a cam surface 76 for engagement with a complimentary aperture 78 of a selection plate 80. Selection plate 80 further includes spring location portion 82 for housing a coil spring 84 and selection lug 86 for engagement with the axially extending slot 54 in the secondary torsion spring 22. Upon assembly, selection plate 80 will be slidably located in a recess 88 )shown on Figure 2) within the secondary side 30 of housing 14. A cover plate 90 is fixed to housing 14 to retain both stub shaft 74 and selection plate 80 in position during operation. Finally, a secondary dial 92, which is fixed on to the end of stub shaft 74 by screw fasteners, completes the main components of secondary control device.

[0053] It will be appreciated that by upon assembly, rotation of secondary dial 92 causes the selection plate 80 to laterally move from an unengaged configuration to an engaged configuration, whereby the selection lug 86 is engaged with slot 54 of the secondary torsion spring 22 thereby providing a single secondary counterbalance torque.

[0054] As more clearly shown with reference to Figure 2, due to the shape of recess 88, the selection plate locks and holds its position in the unengaged configuration relative to housing 14. Upon reaching the engaged configuration, the periphery of secondary torsion spring 22 is held in position with respect to the housing thereby applying a secondary resistive torque on the shaft 16. Conversely, in the unengaged configuration, the periphery of the secondary torsion spring is substantially free to rotate with said shaft and provides no secondary resistive torque.

[0055] As will be evident to those skilled in the art, the secondary control device 28 will not be able to reach the engaged configuration if the secondary torsion spring is not horizontally aligned. It is for this reason that spring 84 has been provided to bias the selection plate to the engaged configuration thereby allowing the user to rotate platform 34 and shaft 16 until the lug 86 positively 'clicks' into position.

[0056] Therefore, by using the secondary control device 28 double the amount of torque values - sixteen in total - can be achieved over solely using the primary control device. Since it proposed that the resistive torque provided by the secondary torsion spring is half that provided by the primary torsion spring, the sixteen torque values provided are equally spaced.

[0057] With reference now to Figure 6, the counterbalance resistive torque is set by rotating the primary dial 68 to the desired numeric value as indicated on the rotary scale 72, and secondary rotary dial to the engaged or disengaged position. As can been seen, rotary scale 72 includes a numeric values deposed on its right and left sides, which correspond to the engagement of the secondary control device. In other words, a higher torque value will be applied upon engagement of the secondary control device. Therefore, if the secondary control device 92 is not engaged, as shown in the "A" configuration in Figure 6, the left hand side values of the rotary scale 72 will apply. If the secondary control device 92 is engaged, as shown in the "B" configuration in Figure 6, the right side values of the rotary scale 72 will apply. .

[0058] The primary dial 68 is accordingly rotated one step followed by an optional rotation of the secondary dial. The process is then repeated to gradually increase the counterbalance torque until the camera holds its angular position. Of course, the process can be reversed to decrease the counterbalance torque. A required level of counterbalance torque can then be achieved.

[0059] It will also be understood that, in an alternative embodiment, the apparatus may include two or more secondary torsion springs. Here, the secondary torsion springs may be arranged in a similar configuration as described above for the primary torsion springs. In this alternative embodiment, the secondary control device could be movable between a plurality of selectable positions including an unengaged position, a fully engaged position, and incremental positions there between. Similar to the operation of the primary control device, each position of the secondary control device corresponds to the application of a different level of secondary resistive torque on the shaft.

[0060] With reference to Figures 7 to 9, there is depicted a further embodiment of the present invention. This embodiment is similar to the embodiment discussed above, however, in this version, a non selectable fixed torsion spring 90 has now been provided. Fixed torsion spring 96 is in keyed engagement with main rotational shaft 16. Fixed torsion spring 96 differs from the primary and secondary torsion springs in that its outer peripheral ring 94 is permanently held in position with respect to housing 14. In this way, a counterbalance torque is always applied upon rotational shaft 16.

[0061 ] To this end, using this arrangement, there will always be a spring counterbalance torque applied to the tripod head even when neither the primary or secondary torsion spring are engaged so that the tripod head remains in a horizontal position at rest.

[0062] Typical use of the apparatus initially involves placing a camera with lens on the mount or tripod such that its centre of weight is aligned with the centre point of the apparatus or shaft 16.

[0063] It will be appreciated that providing a secondary selection device, a supplementary counterbalance torque may be provided without complicating the primary torque selection device. As a result, sixteen discreet and evenly spaced counterbalance torque values are provided. At the same time, the counterbalance system proposed is not much more cumbersome or expensive to manufacture than existing systems and therefore has a commercially advantageous packaging. Specifying equal resistive torque elastomeric spring elements in the primary torsion springs and a half torque in the secondary torsion spring provides an evenly progressive and stepped counterbalance torque is provided by stepped rotation of the primary and secondary selection dials. [0064] It should be appreciated that in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, Figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Description are hereby expressly incorporated into this Description, with each claim standing on its own as a separate embodiment of this invention.

[0065] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0066] While there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as falling within the scope of the invention. For example, any formulas given above are merely representative of procedures that may be used. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope of the present invention.