JPS6364794B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display device that displays measured values using a number wheel or the like, and particularly to a machine that has an improved clutch mechanism that can perform the zero return operation and the drive force transmission/separation operation reliably and accurately. This relates to a type digital display.

Generally, the structure of this type of mechanical digital display is such that a numeric wheel train is driven from a drive side gear via a step mechanism, and conventionally, when the character train returns to zero, the gear train is separated. A device that reverses the number train by separating the step mechanism and reversing the number train.
Alternatively, a clutch mechanism such as a friction clutch or a multi-tooth clutch was used to return the number wheel and the driving gear independently to zero.

When returning to zero, in a method that does not separate the gear train leading to the number wheel of the digital display, the rotational force from the zero return shaft is transmitted to the number wheel of the lowest digit in the number train, performing a reversal, and then The disadvantage is that it requires excessive force and a long time to return the digit wheel to zero, and methods that use a friction clutch cause slippage, causing errors in rotation angle and weighing values. Furthermore, in the method using a multi-tooth clutch, once the teeth have been separated, it is difficult to match the peaks and valleys of the teeth when reocclusaling, resulting in uncertain and inaccurate measured values, which remains a problem. .

This invention eliminates the above-mentioned drawbacks, has a clutch mechanism that enables reliable and accurate transmission, separation, and engagement, and is a mechanical digital display that can achieve quick zero return operation and accurate and reliable weighing display. The purpose is to provide equipment.

In order to achieve this object, according to the present invention, a clutch mechanism is provided in the gear train extending from the reversible drive shaft to the step mechanism, and the clutch teeth are
The number of teeth is a specific number obtained by multiplying the number of steps per revolution of the step mechanism by the gear ratio of the gear train from the step mechanism to the clutch, or an integral multiple thereof. Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an embodiment of a mechanical digital display for a maximum demand meter to which the present invention is applied. The structure of the embodiment of the present invention will be described with reference to FIG. 1. The structure includes a transmission device zero return mechanism A, a zero return clutch portion B, a step drive device C, a display device D, and a zero return device E for the display device. A step-by-step explanation will be given below.

Transmission device zero return mechanism A For example, a driving force proportional to a measured value is transmitted to the shaft 1. A pin 3 provided on an arm 2 fixed to the shaft 1 transmits rotational motion in the forward direction to an arm 4 set on the shaft 5 of the gear 6. gear 6
A crown gear 12 and a lever 9 are fixed to a shaft 8 that is fitted onto a gear 7 that is transmitted from the shaft.
A helical spring 10 is connected to the lever 9 to provide restoring force, and in the zero state, a fixing pin 11 is in contact as a stopper. Therefore, the lever 9 and the fixed pin 11 are opened under the condition that the zero return clutch part B, which will be described later, is in a separated state and the shaft 1, arm 2, and pin 3 are rotated in the opposite direction, that is, due to the zero return operation. In the measuring state, the crown gear forming one of the clutch teeth rotates until the lever 9 at the end of the shaft 8 comes into contact with the fixed pin 11 and then stops, so it automatically zeros without any deviation of a single tooth. state and always return to the same position.

Zero return clutch part B A crown gear 13, a flange-shaped projection 14, and a gear 16 are integrated and loosely engaged with the shaft 8. Furthermore, an arm 20 attached to an arm support rod 21 that rotates around a shaft 22 is inserted into a groove 15 formed by the flange-shaped projection 14 and the gear 16, and the crown gear 13, the flange-shaped projection 14, and the gear 16 are integrated. The clutch mechanism composed of the crown gear 12 and the crown gear 13 is transmitted and separated. Also, the gear 17 meshes with the gear 16,
Even during the changing operation of transmission and separation, the occlusion position of both changes in the axial direction, but the occlusion remains unchanged. A crown gear 1 is attached to the shaft 18 to which the gear 17 is fixed.
9 is fixed and the gear 23 is meshed. Furthermore, a shaft 25 to which a gear 23 is fixed communicates with a step mechanism C, which will be described later, and a gear 24, which is also fixed to the shaft 25 like the gear 23, communicates with a display device D, which will be described later. Fig. 5 shows the clutch mechanism in its transmission state, and Fig. 6 shows its disengaged state.

Step Drive Device C A magnetic disk 26 is fixed to the other end of the shaft 25 on which the gear 23 is fitted, which is magnetized so that N and S polarities are arranged on one side, for example, as shown in FIG. There is. Also, this magnetic disk 2
A magnetic disk 2, which is the same as the magnetic disk 26, is placed opposite the magnetized surface of the magnetic disk 26 at a constant interval.
7 are fixed with their magnetized surfaces facing each other. With this structure, when the magnetic disk 26 rotates, it jumps to the next maximum attractive magnetic force point when it exceeds the maximum repulsive magnetic force point and performs a step operation, but the drive side response to the jump rotation is This is achieved by creating a gap between the pin 3 of the arm 2 fixed to the shaft 1 and the pin 4 fixed to the shaft 5.

Display Device D A gear 24 fixed to a shaft 25 meshes with a gear 28 rotatably provided on a shaft 30. The cam plate 29 is rotatably provided on the shaft 30 together with the gear 28. The cam plate 29 meshes with a feed wheel 31 that is loosely engaged with the shaft 32. The number wheel 34 has unevenness on its inner surface, and is combined with a gear 49 that meshes with the feed wheel 31 and an integral ratchet wheel 33 to form a ratchet mechanism.
3, but when returning the display to zero, the number wheel 34 can rotate independently, and at the zero display position, the gear 51 of the number wheel 34 rotates.
Rotation stops due to a part of it being missing. Further, digital display is possible because the cam plate 29 is set to rotate the feed wheel 31 only when the step drive device C performs a jump operation.

Zero return device E for display device A bevel gear 35 is fixed to a zero return drive shaft 41 for returning the number wheel 34 of the display device D to zero, and a bevel gear 35 and a bevel gear 36 are loosely coupled to the shaft 43. Rotation is sequentially transmitted to an integrated gear 37, a gear 38 fixed to a shaft 44, and a gear 39.
Further, the swing frame 42 rotates around the shaft 43 when the shaft 40 is pushed during the zero return operation, and the gear 39 engages with the gear 51 provided on the number wheel 34 to rotate the number wheel 34. Swing frame 4
A pin 50 is provided on a gear 49, and a setting pawl 47 is fixed on a shaft 45 and a shaft 46 fixed to the pin 50.
The gear 49 is set by contacting the gear 49. axis 46
After the zero return operation is completed, a helical spring 48 is applied to provide a force to restore the swing frame to its original position when the force applied to the shaft 40 is removed.

As described above, each element is configured as a digital display, and the principle and operation of the clutch mechanism and its surroundings, which is a feature of the present invention, will be explained with reference to FIGS. 2 and 3.

FIG. 2 shows the weighing state immediately before returning to zero. The fixing pin 11 and the lever 9 are in a separated state, and the magnetic disk 26 is at an arbitrary position with respect to the other magnetic disk 27. At this time, as a zero return operation, the arm 20 pushes the gear 16 as shown in FIG. 3, and the crown gear 13 integrated with the gear 16 moves in the axial direction, and the connection with the crown gear 12 is separated. , the crown gear 13 rotates forward or reverse due to the attractive force of the N and S poles of the magnetic disks 26 and 27 until the magnetic disk 26 stops at the maximum point of attractive force, and then stops at a specific position. and maintain that state.

Here, crown gear 19, gears 16, 17, 2
The number of teeth of 3 and 24 is Z ₁₉ , Z ₁₆ , Z ₁₇ , Z ₂₃ , Z ₂₄ ,
If the number of N or S poles of the magnetic disks 26, 27, that is, the number of steps per rotation of the magnetic disk 26, is n, then the number of teeth of the crown gears 12, 13 constituting the clutch mechanism is Z ₁₂ , Z ₁₃
, Z ₁₂ = Z ₁₃ = n・Z ₁₉・Z ₁₆ /Z ₂₃・Z ₁₇ (or Z ₁₂ = Z ₁₃ = N・n・Z ₁₉・Z ₁₆ /Z ₂₃・Z ₁₇ …N
is a positive integer), the relative positions of the peaks and troughs of the teeth of the crown gear 13 with respect to the crown gear 12 are always constant.

On the other hand, the crown gear 12 rotates in reverse until the lever 9 comes into contact with the fixing pin 11 due to the reverse rotation of the driving shaft 1, but the position at which it stops is always constant. Therefore, by setting the engagement of the crown gears 12 and 13 accurately in the initial zero state, the clutch, that is, the crown gears 12 and 1
This means that the re-biting in step 3 can be done accurately and quickly without even a single tooth error.

As described above, according to the present invention, the gear train up to the step mechanism of the display is configured to be transmitted and separated by a clutch having a specific number of teeth or an integral multiple thereof, so that the numeric gear train can be quickly returned to zero. Not only is it possible to re-engage the clutch accurately and reliably, it has the effect of significantly reducing measurement errors.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a perspective view showing the clutch portion in the clutch transmission state, FIG. 3 is a perspective view showing the clutch portion in the clutch disengaged state, and FIG. 4 is a perspective view showing the clutch portion in the clutch disengaged state. FIG. 5 is a sectional view of the clutch mechanism showing the clutch transmission state, and FIG. 6 is a sectional view of the clutch mechanism in the clutch disengaged state. In the figure, A is the transmission device zero return mechanism, B is the zero return clutch, C is the step drive device, D is the display device, E is the zero return device for the display device, 1, 5, 8, 1.
8, 22, 25, 30, 32, 40, 43, 4
4, 45, 46 are shafts, 2, 4, 20 are arms,
3, 11, 50 are pins, 6, 7, 16, 17, 2
3, 24, 28, 37, 38, 39, 49, 51
9 is a gear, 9 is a lever, 10, 48 is a spiral spring, 12, 13, 19 is a crown gear, 14 is a collar-shaped projection, 15 is a groove, 21 is an arm support rod, 2
6 and 27 are magnetic disks, 29 is a cam plate,
31 is a feed wheel, 33 is a ratchet wheel, 34 is a number wheel, 35 and 36 are bevel gears, 41 is a zero return drive shaft,
42 is a swing frame, and 47 is a setting claw.

Claims (1)

[Claims] 1. In a device equipped with a gear train that returns to its initial position in the separated state and a device that transmits and separates rotational motion between the gears of an indicator with a step mechanism, the speed per rotation of the step mechanism is A clutch mechanism having a specific number of teeth obtained by multiplying the number of steps by the gear ratio of the gear train from the step mechanism to the part that performs transmission and separation, or a number of teeth that is an integral multiple of the specific number. A mechanical digital display that is characterized by having