JPH0248834Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a device for preventing over-rotation of a sprocket shaft for winding a film during winding and stopping it at a fixed position.

``Prior art and its problems'' In cameras that wind the film by driving a sprocket shaft that engages with the perforation of the film by the film winding mechanism, the film winding mechanism uses the winding speed difference and the rewinding knob to adjust the speed of the film. Due to the operation of removing slack, etc., the spacing between adjacent screens becomes uneven, and in the worst case, the adjacent screens overlap. This is caused by play between the constituent members of the film winding mechanism, backlash of gears, and inertia of the winding member. Particularly, the unevenness of the screen spacing due to the difference in winding speed is caused by the inertia of the winding member causing the sprocket shaft to over-rotate, resulting in the film overrunning.

For this reason, various fixed position stop devices have been proposed to prevent over-rotation of the sprocket shaft. One is to attach an elastic member to the sprocket shaft,
A sprocket stop member interlocked with the film winding mechanism is pressed against this elastic member at the final stage of film winding to stop the rotation of the sprocket shaft. However, with this device, the winding torque of the film increases at the final stage of winding, and there are also problems with the durability of the elastic member. On the other hand, there is a device in which a locking pawl is fixed to the sprocket shaft by means such as spline connection, and a sprocket stopping member is engaged with the locking pawl at the final stage of film winding to stop the rotation of the sprocket shaft. teeth,
It has the characteristic that there is no change in hoisting torque. However, this conventional device has a problem in that it is not possible to continuously adjust the phase of the sprocket shaft and the locking pawl.
A gap sometimes occurred between the stop pawl of the sprocket stop member and the stop pawl that engaged with the sprocket stop member. This gap adversely affects the accuracy of the stop position of the sprocket shaft.

``Purpose of the invention'' The present invention is a sprocket fixed position stopping device of the latter type of the above-mentioned conventional device, that is, a type in which a locking pawl is provided on the sprocket shaft and the locking pawl is engaged with a sprocket stopping member. The object of the present invention is to provide a device that can freely adjust the phase between the locking claw and the locking claw. Another object of the present invention is to provide a device in which the position of the locking pawl on a sprocket shaft will not be misaligned even if the pawl of the sprocket shaft contacts the sprocket stop member with an impact.

``Summary of the invention'' The sprocket fixed position stopping device of the present invention has threads on the sprocket shaft or a rotating member interlocked with the sprocket shaft that have different diameters and pitches, and the direction of the threads is fixed when the film is wound on the sprocket shaft. A large and small male threaded portion is provided in the direction of rotation, a pawl ring having a locking pawl around the periphery that engages with the sprocket stop member is screwed into the large diameter male threaded portion, and a tightening nut is screwed into the small diameter male threaded portion. The pawl ring is brought into contact with the end face of the pawl ring, thereby preventing the pawl ring from rotating in a direction opposite to the winding direction of the sprocket shaft. According to this configuration, by changing the screwing position of the pawl ring with respect to the sprocket shaft, the phase between the locking pawl and the sprocket shaft can be freely adjusted. In addition, by bringing the tightening nut into contact with the end face of the pawl ring after adjustment, even if the locking pawl and the sprocket stopping member contact each other with impact, the pawl ring will not rotate relative to the sprocket shaft. This can prevent the locking pawl from becoming misaligned.

``Embodiments of the invention'' The invention will be described below with reference to illustrated embodiments. 1 to 3 are views of the upper part of the film winding of the camera viewed from the bottom, with FIG. 1 showing the state before winding and FIG. 2 showing the state after winding is completed, respectively. Camera body 11
The film winding shaft 12 and the sprocket shaft 1 are shown in FIG.
3 are rotatably supported, and the film F is unwound from a rewinding shaft (not shown) on the right side of the figure. It is wound up on the winding shaft 12. Arrows A and B indicate the rotational directions of the winding shaft 12 and sprocket shaft 13 during film winding.

A lower hoisting disk 15 and a joint 16 are fixed to the lower end of the hoisting shaft 12 by a set screw 14, and the lower hoisting disk 15 has a shutter pin 17 and a mirror pin 18 implanted around its periphery. It is set up. One end of the shutter charge lever 20 is pivotally attached to the shutter pin 17, and the mirror pin 18
A collar 21 is rotatably fitted in the holder. A shutter charge pin 22 is provided at the other end of the shutter charge lever 20, and this shutter charge pin 22 is slidably fitted into a guide groove 24 of a main plate 23. The main plate 23 is fixed to the camera body 11 with three fixing screws 25.

A mirror charge lever 27 is pivotally attached to the main plate 23 by a charge lever shaft 26, and the left side of the mirror charge lever 27 in the figure is an engaging part 27a with the collar 21, and the right side is a mirror charge pin. 28 and serves as an engaging portion 27b. This mirror charge lever 27 has a stop groove 29 that can be engaged with a lock pawl 50 provided on the sprocket shaft 13.
The restoring spring 31 moves the mirror charge lever 27 in the direction in which the stop groove 29 moves away from the sprocket shaft 13, that is, in the clockwise direction in the figure.
is biased to rotate.

A reversal prevention ratchet 33 is also pivotally attached to the camera body 11 via a ratchet shaft 32. The reversal prevention ratchet 33 meshes with a gear portion 15a formed around a portion of the lower hoisting disk 15, and functions to prevent the hoisting shaft 12 from being reversed during hoisting. 34 is this reversal prevention ratchet 33
It is a restoring spring.

The present invention is characterized by a support structure for the locking pawl 50 provided on the sprocket shaft 13, and this support structure will be explained with reference to FIG. Sprocket shaft 1
3 has a large diameter threaded portion 51 and a small diameter threaded portion 52 successively formed at its lower end. Large diameter threaded part 51
A pawl ring 53 having three locking pawls 50 at equal intervals (120° intervals) is screwed onto the small diameter screw portion 52, and a bag-shaped tightening nut 54 is screwed onto the small diameter screw portion 52.
are screwed together, and the abutment surface 54a at the upper end of the tightening nut 54 abuts the end surface (lower surface) of the pawl ring 53. And this double screw part 51,
The direction of the screw 52 is the same as the direction of rotation of the sprocket shaft 13 during film winding. Further, the thread pitch is different between the large diameter threaded portion 51 and the small diameter threaded portion 52. In other words, the direction of the threads of the threaded portions 51 and 52 is set in such a direction that the sprocket shaft 13 moves forward when the sprocket shaft 13 is rotated in the film winding direction. By setting the direction of the screw in this way, when the stop groove 29 of the mirror charge lever 27 and the locking pawl 50 are engaged and the rotation of the sprocket shaft 13 is abruptly stopped, the pawl ring 53 will lock into the tightening nut. receives a force in a direction approaching 54. Therefore, when the pawl ring 53 and the tightening nut 54 are in contact with each other, rotation of the pawl ring 53 is prevented. Since the thread pitches of the large diameter threaded portion 51 and the small diameter threaded portion 52 are different, the tightening nut 54 is not rotated together by the pawl ring 53.

In this device having the above configuration, the claw ring 53
It is assumed that the phase between the sprocket shaft 13 and the sprocket shaft 13 is adjusted correctly, and that the abutting surface 54a of the tightening nut 54 is tightly fixed to the lower surface of the pawl ring 53. In this state, when the film is wound by a winding lever or a motor (not shown), the winding shaft 12
And the sprocket shaft 13 rotates in the directions of arrows A and B, respectively. When the winding shaft 12 rotates in the direction A, the lower winding disk 15 rotates together with it, and the shutter pin 17 pulls the shutter charge lever 20 and moves the shutter charge pin 22 into the guide groove 24.
within the figure to the left. This movement of the shutter charge pin 22 charges a shutter (not shown). At the same time, the mirror pin 18 rotates, and its collar 21 moves to the mirror charge lever 27.
Press the engaging portion 27a at the left end in the figure to release the restoring spring 3.
Rotate the mirror charge lever 27 counterclockwise in the figure against the force of 1. Then, the engaging portion 27b at the right end of the mirror charge lever 27 in the figure pushes the mirror charge pin 28, thereby charging the mirror (not shown).

FIG. 2 shows the state at the moment when the above-mentioned shutter charge and mirror charge are completed. At this time, the stop groove 29 of the mirror charge lever 27 engages with one of the locking pawls 50 of the pawl ring 53 of the sprocket shaft 13, Prevents over-rotation of the sprocket shaft 13. The engagement between the stop groove 29 and the locking pawl 50 occurs with an impact, and the pawl ring 53 is therefore subjected to a force that tends to rotate it in the counterclockwise direction in FIG. However, the fact that the pawl ring 53 receives a force in the counterclockwise direction in FIG. 2 means that the pawl ring 53 moves toward the tightening nut 54, as is clear from the direction of the thread of the large diameter threaded portion 51 mentioned above. That is, in FIG. 4, the pawl ring 53 is lowered. However, since the lowering of the pawl ring 53 is prevented by the tightening nut 54, the pawl ring 53 rotates and the sprocket shaft 13
The position of the locking pawl 50 relative to the locking claw 50 will not be misaligned. What is important here is that the thread pitches of the large diameter threaded portion 51 and the small diameter threaded portion 52 are different. Assuming that both thread pitches are the same, when the pawl ring 53 receives rotational force, the tightening nut 54
There is a risk that they will rotate at the same time, but if the pitches of the two are different, the tightening nut 54 will rotate against the pawl ring 5.
It does not rotate together with 3. Furthermore, if the directions of the large-diameter threaded portion 51 and the small-diameter threaded portion 52 are the same, when the pawl ring 53 is suddenly stopped, the tightening nut 54 will rotate in the direction of rotation of the sprocket shaft 13 due to inertia. As the tightening nut 54 approaches the pawl ring 53 more closely, the locking action of the pawl ring 53 by the tightening nut 54 becomes more reliable.

After hoisting is completed, when the hoisting lever returns to its original position or the hoisting motor clutch reverses,
The lower hoisting disk 15 is reversed, and the mirror charge lever 27 and shutter charge lever 20 are in the first position.
Return to the initial state shown in the figure.

Next, when assembling and adjusting this device, sprocket shaft 1
3 and 4 show how to adjust the phase between 3 and the locking pawl 50.
The diagram will be explained. First, the tightening nut 54 is loosened to create a gap between the abutment surface 54a and the lower surface of the pawl ring 53, so that the pawl ring 53 can rotate. In this state, the lower winding disk 15 is set to the completed film winding state, and then the claw ring 53
3 in the direction of arrow B in FIG.
to engage the stop groove 29 of. The pawl ring 53 moves in the axial direction by rotation, but this movement amount is at most p/3 of the thread pitch p of the small diameter threaded portion 52, so there is no problem. Thereafter, when the tightening nut 54 is tightened using its sliding groove 54b and its abutment surface 54a is brought into strong contact with the lower surface of the pawl ring 53, the pawl ring 53 and the tightening nut 54 are attached to the sprocket shaft 13. Fixed. At this time, the locking claw 50
is engaged with the stop groove 29, so the pawl ring 5
3 will not rotate. Therefore, by arbitrarily adjusting the position (phase) of the locking pawl 50 with respect to the sprocket shaft 13, the gap between the stop groove 29 and the locking pawl 50 can be adjusted to zero.

In the above embodiment, the pawl ring 53 and the tightening nut 54 are screwed directly onto the sprocket shaft 13, but the same effect can be obtained by screwing these onto a rotating member that interlocks with the sprocket shaft 13. . Further, in the above embodiment, since the locking claws 50 are provided around the claw ring 53 at intervals of 120 degrees, the locking claws 50 are sequentially engaged with the stop grooves 29 each time the film is wound up. This is advantageous in terms of durability. To do this, the sprocket shaft 13 (claw ring 53) must be rotated by 120° x (3n-1) or 120° x (3n-2) (n is a positive integer) during each winding of the film. All you have to do is make it rotate.

Further, in the above embodiment, the mirror charge lever 27 is used as the sprocket stopping member, but
In the present invention, any other member can be used as the sprocket stop member as long as it operates in conjunction with the film winding mechanism.

Note that the tightening nut 54 is as shown in FIG.
By protruding outward from the lower decorative plate 60, it can also be used as a rewind button (R button).

"Effects of the Invention" As described above, according to the sprocket fixed position stopping device of the present invention, the phase between the sprocket shaft and the locking pawl provided on the sprocket shaft can be freely adjusted steplessly. Easy to assemble and adjust. In addition, the assembly and adjustment can be done simply by placing the locking pawl against the sprocket stop member and then tightening the tightening nut.
Assembly accuracy is not affected by the level of proficiency of the operator, and reliability can therefore be improved. Furthermore, since it is mechanically simple, it is less likely to break down and is advantageous in terms of cost. Furthermore, since the tightening nut receives the rotational force that the pawl ring receives when the locking pawl receives an impact force, the locking pawl will not be misaligned.

[Brief explanation of drawings]

Figures 1 and 2 are bottom views of the camera in different operating states, showing an embodiment of the sprocket fixed position stopping device of the present invention, Figure 3 is a bottom view of the camera showing the assembled and adjusted state, and Figure 4 is a bottom view of the camera in different operating states. 2 is a sectional view taken along the line - in FIG. 2. FIG. 11... Camera body, 12... Winding shaft, 13...
... Sprocket shaft, 27 ... Mirror charge lever (sprocket stopping member), 50 ... Locking pawl,
51...Large diameter threaded part, 52...Small diameter threaded part, 53
...Claw ring, 54...Tightening nut.

Claims (1)

[Claims for Utility Model Registration] (1) A sprocket shaft that meshes with the perforation of the film; a film winding mechanism that rotates the sprocket shaft and the film winding shaft; and a film winding mechanism that is interlocked with the winding operation of the film winding mechanism. A fixed position stopping device for a camera sprocket, comprising a sprocket stop member that operates to stop the rotation of the sprocket shaft by engaging with the sprocket shaft or a member interlocking with the sprocket shaft. The rotating member that interlocks with the shaft is provided with large and small male threaded parts with different thread diameters and pitches, and both thread directions are in the direction of rotation of the sprocket shaft during film winding. a pawl ring having a locking pawl that engages with a sprocket stop member;
A camera characterized in that a tightening nut is screwed onto the small-diameter male screw portion to abut against the end face of the pawl ring and prevent the pawl ring from rotating in a direction opposite to the winding direction of the sprocket shaft. Sprocket fixed position stop device. (2) In claim 1 of the utility model registration claim, the sprocket stopping member consists of a mirror charge lever that swings as the film is wound;
A camera sprocket fixed position stopping device in which the mirror charge lever is provided with a stopping groove that engages with a locking pawl of a pawl ring. (3) In claim 1 or 2 of the utility model registration claim, a plurality of locking claws are provided at equal angular intervals around the claw ring, and the plurality of locking claws are arranged in one roll of the film. A fixed position stop device for a camera sprocket, in which the rotation angle of the sprocket shaft is set so as to sequentially engage a sprocket stop member for each sprocket.