GB2393505A

GB2393505A - Adjustable photographic reflector device

Info

Publication number: GB2393505A
Application number: GB0318536A
Authority: GB
Inventors: Daniel Ferro; Francois Portmann
Original assignee: Bron Elektronik AG
Current assignee: Bron Elektronik AG
Priority date: 2002-08-09
Filing date: 2003-08-07
Publication date: 2004-03-31
Also published as: GB0318536D0; SE0302058D0; SE0302058L; DE10236517A1

Abstract

A reflector device for photographic purposes, comprises a reflector screen 1 which can be tensioned and which comprises spokes 5 arranged distributed over its periphery and a reflector covering 8. The device further comprises a handle 2 on which the reflector screen is supported, and support means for at least one light source 6 which is displaceable relative to the reflector screen. The handle 2 engages over at least part of its displacement path with a threaded portion (34 fig 5) for adjusting its position relative to the reflector screen.

Description

Reflector Device for Photographic Purposes The invention relates to a

reflector device for photographic purposes according to the preamble of Claim 1.

Depending upon their purpose, reflector screens for photographic purposes have to be relatively large in order to achieve the desired illumination effect. Reflector devices are known (EP 0 806 606 Al) in which the reflector screen is connected to a handle which projects through the crown of the reflector screen and to which the light source is fastened. A cross brace, which can be actuated by a slide displaceable on the handle, is used for tensioning the reflector screen. The slide is displaced until the braces of the cross brace are pressed beyond a dead centre in the direction towards the crown of the reflector screen. The forces required to tension the reflector screen are high, as a result of which the tensioning procedure is made difficult on account of the unwieldy dimensions. The handle has to be displaced for focussing the light source, and this requires considerable force on account of the heavy weight of the reflector screen. If the light source has to be moved very far, as far as the level of the free edge of the reflector screen, the part of the handle projecting to the rear beyond the screen is still short, so that a considerable force is likewise required for manipulating the reflector device.

The object of the invention is to design a reflector device of the type defined in the preamble in such a way that only slight actuating forces are required for tensioning the reflector screen and for focussing the light source, without the manipulation of the reflector device being adversely affected as a result.

In the case of a reflector device of the type defined in the preamble, this object is attained according to the invention with the characterizing features of Claim 1.

In a case of the reflector device according to the invention the handle is displaced in order to open the reflector screen. As the reflector screen is opened to an increasing extent, the force required for completely opening the reflector screen increases. On account of the threaded portion towards the reflector screen it is made possible for the last part of the tensioning path to be covered with little expenditure of force.

- 2 Further features of the invention are set out in the further claims, the description and the

drawings. The invention is explained in greater detail with reference to an embodiment illustrated in the drawings, in which Fig. 1 is a view of a reflector screen of a reflector device according to the invention for photographic purposes; Fig. 2 is a side view of the reflector device according to the invention; Fig. 3 is a view in the direction of the arrow III in Fig. 2; Fig. 4 shows an inclination-setting unit of the reflector device according to the invention in an enlarged illustration and in section along the line A-A in Fig. 5; Fig. 5 is a section along the line B-B in Fig. 6, and Fig. 6 is a section along the line C-C in Fig. 5.

The reflector device has a reflector screen 1 which is mounted on a screen rail 2. It projects to the rear beyond the reflector screen and acts as a handle for orientating the screen.

The reflector screen 1 is constructed in a known manner and can have diameters in the range of between 2 and 4 m for example, depending upon the case of application for which the reflector screen 1 is to be used. The reflector screen 1 is mounted with a crown 3 in a displaceable manner on the screen rail 2. A cross brace 4, the braces 28 of which are anchored at one end to the screen rail and are articulated at their other end to spokes 5 of the reflector screen 1, is provided for tensioning the reflector screen 1.

In the tensioned state the reflector screen 1 surrounds a light source 6 which is connected to a focussing device 7. The light source 6 can be displaced by the said focussing device 7 in the axial direction of the screen rail 2 for focussing purposes.

The reflector device is designed in such a way that the screen rail 2 projects sufficiently far to the rear beyond the reflector screen 1 for it to be capable of being used conveniently as a handle. The focussing device 7 is designed in such a way that it does not affect the structural depth of the reflector device. The functions of the screen rail 2 and of the focussing device 7 are separate from one another. The focussing device 7 can be actuated independently of the screen rail 2.

The reflector screen 1 is designed in a paraboloidal shape in the tensioned state and has a screen covering 8 which is fastened in a known manner to the radially extending spokes 5. As

- 3 shown in Fig. 3, the braces are arranged uniformly distributed over the periphery of the reflector screen and are articulated by their ends radially on the inside to the crown 3. In the region of the crown 3 the reflector screen I is provided with a plate-shaped holding means 9 which has a central through-opening l O (Fig. 5) for the screen rail 2 and the focussing device 7. An intermediate holder 11, which projects with a central attachment 12 through the through-opening 10 in the holding means 9, is fastened to the outside of the holding means 9.

The holding means 9 abuts against the attachment 12 with the edge of the through-opening 10. A catch element 13, which is constructed in the form of a spring-loaded bolt which engages with its end situated radially on the inside in a catch opening 14 in a sleeve 15, is mounted in the intermediate holder 11. A holding plate 16, which is fastened to the holding means 9 by screws 17 (Figs. 4 and 5) with the interposition of the intermediate holder 11, is arranged on the side of the intermediate holder 11 remote from the holding means 9. The holding plate 16 projects radially beyond the holding means 9 and the intermediate holder 11 and carries at its free end an inclination-setting unit 18 which is known per se and so will not be described in greater detail. The reflector screen 1 together with the screen rail 2 and the focussing device 7 can be set by the said inclination-setting unit 18 in directions at right angles to one another and can be clamped in a fixed manner by clamping levers 19, 20 in the position set in each case. The holding plate 16 is provided at its free end with a transversely projecting tube member 21 on which the inclination-setting unit 18 is clamped by the clamping lever 19.

The screen rail 2 has a gripping tube 22 which projects through the crown 3 and is surrounded at a distance by the sleeve 15 inside the reflector screen 1. A sleeve 23, on which the gripping tube 22 rests and which is provided with a flange 24 directed radially outwards, is inserted into the end of the gripping tube 22 towards the screen. The flange 24 rests on a holding plate 25 (Fig. 5) which is orientated outwards substantially radially and is mounted with a central attachment 26 on the end of the gripping tube 22 towards the screen. In this way the said end of the gripping tube 22 is held between the sleeve 23 and the attachment 26.

The sleeve 23 is fastened to the holding plate 25 in an abutting manner by screws 27 which pass through flanges 24.

Those ends of the radially extending tensioning braces 28, which form the cross brace 4 used for tensioning the reflector screen 1, are articulated to the edge of the holding plate 25.

As shown in Fig. 2, the braces 28 are inclined contrary to the spokes 5. The ends of the braces 28 remote from the holding plate 25 are articulated to the spokes 5 of the reflector screen 1 in the vicinity of the crown 3. In the clamping position illustrated in Figs. 2 and 5 the braces 28 form an acute angle - which is only slightly less than 90 - with the axis of the gripping tube 22.

- 4 The cylindrical attachment 26 of the holding plate 25 rests against one end of the sleeve 15 which surrounds the gripping tube 22 at a distance and is fastened to it by a clamping member 29. The sleeve 15 is mounted on the said clamping member 29 and is fastened to it by at least one screw 30. The sleeve 15 projects into the through-opening 10 in the crown 3.

The cylindrical attachment 12 of the intermediate holder 11 directed towards the holding plate 25 rests against the sleeve 15 on which it is held by at least one screw 31.

At its end towards the crown the sleeve 15 rests on a further clamping member 32 to which the sleeve 15 is connected, preferably in a releasable manner.

In the region of the clamping member 32 a gripping sleeve 33 engages over the sleeve 15, the said gripping sleeve 33 being provided in its front region towards the crown 3 with an internal thread 34 with which the gripping sleeve 33 engages in an external thread 35 of the gripping tube 22. The external thread 35 is provided on a threaded segment 36 which is fastened to the gripping tube 22 with screws 37. The threaded segment 36 extends over only a small angular area in the peripheral direction of the gripping tube 22. The threaded segment 36 can also, of course, be constructed in the form of a threaded sleeve which is fastened to the gripping tube 22. As shown in Fig. 5, the sleeve 15 engages over the end of the threaded segment 36 towards the crown at a distance.

The end of the gripping sleeve 33 remote from the crown 3 has an edge 38 which is directed radially inwards and with which the gripping sleeve 33 rests against the gripping tube 22. In this way, the internal thread 34 and the external thread 35 are arranged in a covered manner and are protected from dirt andlor damage in a reliable manner.

At the end towards the crown the gripping sleeve 33 is provided with a flange-like edge 39 which is directed radially outwards and on which one end of a compression spring 40 is supported, the other end of the said compression spring 40 being supported on a holding disc 41. It is fastened to the holding plate 16.

A sleeve-shaped gripping ring 42, which is connected to an internal tube 44 in a fixed manner by way of screws 43, is mounted on the gripping tube 22 in the vicinity of the free end. It is surrounded at a slight distance by the gripping tube 22 and can be displaced with the gripping ring 42 to a limited extent along the gripping tube 22. A guide sleeve 45, by which the internal tube 44 is guided on the inner wall of the gripping tube 22, is mounted on the end of the internal tube 44 situated adjacent to the gripping ring 42. In addition, the internal tube 44 is guided through the sleeve 23 which is inserted into the end of the gripping tube 22

- s - towards the screen.

The screws 43 project through a longitudinal slot 46 in the gripping tube 22. The width of the longitudinal slot 46 corresponds to the thickness of the screws 43, so that during the displacement the internal tube 44 cannot rotate with respect to the gripping tube 22. A cup-

shaped closure member 47 is fastened to the end of the gripping tube 22 situated outside the reflector screen 1.

A sleeve 48, which rests against the inner wall of the internal tube 44 and is provided with a clamping holder 49 outside the internal tube, is fastened in the end of the internal tube 44 towards the screen. It is advantageously formed in one piece with the sleeve 48 and has a clamping screw 50 which passes through it radially and which can be turned by a handle 51.

The end 52 of a lamp support 53, which is held in the internal tube 44 by the clamping screw 50, is inserted into the sleeve 48.

Fig. 5 shows the internal tube 44 in its position inserted completely into the gripping tube 22. In this case the light source 6 is at the minimum distance from the crown 3 of the reflector screen 1 (Fig. 2). The position of the light source 6, which has been displaced to the maximum extent with respect to the gripping tube 22 by means of the internal tube 44, is indicated with broken lines in Fig. 2.

In order to convey the reflector device the reflector screen 1 is folded up and the screen rail 2 is pushed into the folded screen 1. When the reflector screen 1 is to be opened, the screen rail 2 is withdrawn from the crown 3. Since the screen covering 8 is not yet tensioned, the gripping tube 22 can easily be withdrawn. The spokes 5 of the reflector screen I are pivoted outwards by way of the braces 28 of the cross brace 4. As the reflector screen 1 is opened to an increasing extent, the force required for moving the reflector screen 1 into its completely opened position increases. The threaded segment 36 is fastened to the gripping tube 22 in order that the said force can be applied to this last part of the clamping path in a simple manner. When the gripping tube 22 is displaced the threaded segment 36 arrives in the region of gripping sleeve 33, the external thread 35 of the threaded segment 36 coming into engagement with the internal thread 34 of the gripping sleeve 33. By means of the rotation of the gripping sleeve 33 the last part of the clamping path can now be covered without difficulty, since as a result of the engagement of the threads only a slight force is necessary to displace the gripping tube 22 into its end position by the rotation of the gripping sleeve 33.

On the said last displacement path the braces 28 of the cross brace 4 are pivoted into their end position which is illustrated in Fig. 2 and in which the braces 28 spread the spokes 5 of the

- 6 reflector screen 1 apart to such an extent that the screen covering 8 is tensioned. As shown in Fig. 5, the internal thread 34 of the gripping sleeve 33 is relatively short, since the engagement of the threads takes place only at the end of the displacement path of the gripping tube 22.

The light source 6 can be moved by the focussing device 7 into the necessary position relative to the reflector screen 1 independently of the opening and tensioning of the reflector screen 1. The internal tube 44 of the focussing device 7 can be moved to the desired extent relative to the gripping tube 22 by the gripping ring 42. Since the gripping ring 42 is arranged at the free end of the screen rail 2, the focussing device 7 can be actuated in a convenient manner from the rear of the reflector screen 1. Since the internal tube 44 does not project beyond the free end of the gripping tube 22, the screen rail 2 has only a short length, so that when the reflector screen 1 is folded up the reflector device can be conveniently transported.

The maximum displacement path 54 (Fig. 5) is determined by the length of the longitudinal slot 46 in the gripping tube 22.

The reflector screen 1 and thus the entire reflector device have a very low structural depth. When the reflector screen 1 is opened the screen rail 2 projects so far to the rear that it can be used as a handle. Since the focussing device 7 is accommodated inside the gripping tube 22 of the screen rail 2, it does not increase the structural depth of the reflector device.

The braces 28 of the cross brace 4 are very short in relation to the maximum diameter of the reflector screen 1, so that the path for tensioning the reflector screen 1 and thus the length of the screen rail 2 towards the rear are short. The considerable tensioning forces required on account of the short braces 28 are applied without undue effort by rotation of the gripping sleeve 33 in the manner described, when the said gripping sleeve 33 engages with the threaded segment 36 as the gripping tube 22 is withdrawn.

Claims

Claims: 1. A reflector device for photographic purposes, comprising a

reflector screen which can be tensioned and which comprises spokes arranged distributed over its periphery and a reflector covering; the said device further comprising a handle on which the reflector screen is supported, and support means for at least one light source which is displaceable relative to the reflector screen, characterized in that the handle engages over at least part of its displacement path with a threaded portion for adjusting its position relative to the reflector screen.
2. A reflector device according to Claim 1, characterized in that the handle is provided with an external threaded portion for engaging the said threaded portion.
3. A reflector device according to Claim 2, characterized in that the external threaded portion is provided on a threaded segment.
4. A reflector device according to Claim 3, characterized in that the threaded segment is fastened on a gripping tube which forms part of the handle.
5. A reflector device according to one of Claims 1 to 4, characterized in that the said threaded portion is provided on a gripping sleeve.
6. A reflector device according to Claim 5, characterized in that the gripping sleeve surrounds the threaded segment.
7. A reflector device according to Claim 5 or 6, characterized in that the gripping sleeve is held on a holding means to which the spokes of the reflector screen are articulated.
8. A reflector device according to one of Claims 5 to 7, characterized in that the gripping sleeve is rotatable about its axis.
9. A reflector device according to one of Claims 1 to 8, characterized in that the support means for the light source is displaceable relative to the handle.
10. A reflector device according to Claim 9, characterized in that the support means is accommodated inside the handle at least in part.
11. A reflector device according to Claim 9 or lO when dependent directly or indirectely on Claim 4, characterized in that the gripping tube receives the said support means.
12. A reflector device according to Claim 11, characterized in that the support means is an internal tube which is surrounded at a distance by the gripping tube.
13. A reflector device according to one of Claims 9 to 12 when dependent directly or indirectly on Claim 4, characterized in that the gripping tube projects through the crown of the reflector screen.
14. A reflector device according to one of Claims 9 to 13 when dependent directly or indirectly on Claim 4, characterized in that a tensioning device for the reflector screen is provided on the gripping tube.
15. A reflector device according to Claim 14, characterized in that the tensioning device has tensioning braces connected in an articulated manner to the gripping tube.
16. A reflector device according to Claim 15, characterized in that the tensioning braces are arranged inclined contrary to the spokes of the reflector screen in the tensioned position.
17. A reflector device according to one of Claims 9 to 16 when dependent directly or indirectly on Claim 4, characterized in that the gripping tube has at least one longitudinal slot through which fastening elements project which connect a gripping member to the support means.
18. A reflector device according to Claim 17, characterized in that the gripping member is a gripping ring mounted on the gripping tube.
19. A reflector device substantially as hereinbefore described with reference to the accompanying drawings.