JPH01130316A - Cylinder unit - Google Patents

Abstract

PURPOSE:To satisfactorily hold the contacting state between a contact and a drum shaft even in case of the change of the temperature condition by constituting an arm of materials having a sufficient rigidity and providing a mechanism which energizes the arm in such direction that the contact is pressed to the drum shaft. CONSTITUTION:A contact 11 is attached to one end of an arm 121, and the arm 121 consists of materials having such rigidity that the arm sufficiently endures the pressing force of the contact 11 to a drum shaft 4. The arm 121 is fitted to a shaft 15, which is fixed to a holder 14 by caulking, through a hole part 16 and is freely rotated with respect to the shaft 15. When a spring 19 is stretched between a shaft 18 and the arm 121, the contact 11 is pressed to the drum shaft 14. The mechanism which applies a certain pressing force to the contact 11 of an earth terminal 10 is provided in this manner to obtain a cylinder unit which has a high resistance to environments such as temperature and is capable of sure earthing even in case of some deviation of the positional precision of the earth terminal 10.

Description

[Detailed description of the invention]

[Industrial Field of Application 1] The present invention relates to a grounding terminal for grounding a rotating part, particularly in a rotating cylinder of a rotating head type magnetic recording/reproducing device. [Prior Art] FIG. 4 is a perspective view showing a conventional rotary cylinder unit, and FIG. 5 is a sectional view thereof. (1) is the upper cylinder, which has a rotating head (
2) is screwed to this upper cylinder (1). Further, the upper cylinder (1) is screwed to a flange (3), and a drum shaft (4) is press-fitted into this flange (3). Drum shaft (4)
is supported by two bearings (5) and is rotatable. In addition, the magnet (rotor side) of the drum motor (6) is fixed to the drum shaft (4), and (7) is a lower cylinder, which is screwed to the drum base (8), and a magnetic tape is attached to the side. A lead groove (9) is provided for guiding the lower end (not shown). Furthermore, a drum motor coil (stator side) is arranged on the lower surface of the lower cylinder (7), facing the magnet (rotor side) of the drum motor (6). (10) is a ground terminal, which is in direct contact with the drum shaft (4) and has a contact (11) and a contact (11).
) supporting the phosphor bronze arm (12) and the arm (1
2) and a damper (13) for suppressing vibrations. The arm (12) has elasticity and is arranged so that when the contact point (11) and the drum shaft (4) are in contact with each other, it tends to curve downward in a convex direction, as shown in FIG. Further, the ground terminal (10) is screwed to a holder (14) fixed to the drum base (8). Next, the operation will be explained. When reading and writing signals, the magnet (
rotor side), drum shaft (4), and flange (3)
The upper cylinder (1) and the rotating head (2) rotate together. The earth terminal (10) is pressed by the elasticity of the arm (12) against the drum shaft (4) whose contact (11) is rotating, and the drum shaft (4) is connected to the contact (11), the arm (12), It is grounded to the drum base (8) via the holder (14). [Problems to be Solved by the Invention] In the conventional rotary cylinder ground terminal, the arm (12) that supports the contact (11) itself is made of an elastic body. 8), the contact (11) must be forcibly pressed onto the drum shaft (4) and then screwed down, which not only makes the work difficult, but also causes the arm (12) to bend upward from the beginning. There was a problem that there was a high possibility that appropriate pressing pressure could not be obtained. Also, an elastic body that easily vibrates (arm 1
2) is located close to the rotating drum shaft, which tends to cause noise due to resonance.Furthermore, when the damper (13) installed to suppress vibration expands and contracts due to temperature changes, the pressing pressure of the contact changes, resulting in a good There were problems such as the inability to properly ground the device. Furthermore, since the contact pressure is obtained by the elastic force of the arm (12), there is a problem that the pressure tends to vary depending on the accuracy of the mounting position of the ground terminal. This invention was made to solve the above-mentioned problems, and it is possible to easily install a ground terminal and maintain good contact between the contact and the drum shaft even when temperature conditions change. The purpose is to obtain a cylinder unit.

[Means to solve the problem]

The earth terminal of the cylinder unit according to the present invention has an arm supporting the contact made of a material with sufficient rigidity to withstand the pressing pressure of the contact, and furthermore, the arm is arranged in a direction in which the contact is pressed against the drum shaft. A biasing mechanism is provided. [Operation] After the ground terminal according to the present invention is installed in a state where the contact and the drum shaft are not in contact with each other, the arm is energized and the contact is pressed against the drum shaft with a constant pressing pressure.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a cylinder unit that is an embodiment of the present invention. FIG. 2 is a sectional view thereof. FIG. 3 is an exploded perspective view of parts near the ground terminal. The arm (121) has a contact (11) attached to one end and is made of a material with sufficient rigidity to withstand the pressure of the contact (11) against the drum shaft (4). is tightly fitted to a shaft (15) which is caulked to the holder (14) through a hole (16), and is rotatably movable in the shaft (15). (17) is E
The ring prevents the arm (121) from being removed from the shaft (15). Further, the other end of the arm (121) is connected to a shaft (18) crimped to the holder (14) and a spring (
19). Moreover, the arm (121) is
A highly conductive grounding plate that can be bent freely (
20) to the drum base (8). The ground plate (20) is attached to the drum base (8) and the arm (
The arm (121) is screwed to each arm (121).
) is made of a material that is easy to bend so as not to affect the force that presses the contact point (11) of the arm (11) against the drum shaft (4), and the elongated hole (21) allows the screw to be screwed freely even if the position of the arm (121) varies. Care has been taken to ensure that it can be stopped. Next, the operation will be explained. First, when assembling the ground terminal (10), the arm (121) is attached to the holder (14).
The earth plate (20) is screwed to the arm (121). In this state, the holder (14) is screwed to the drum base (8). Next, the spring (19) is connected to the shaft (18) and the arm (121).
). The contact (11) is thus pressed against the drum shaft (14). Finally, the earth plate (2o) is screwed to the drum base (8) at an appropriate position in the elongated hole (21) to complete the assembly. In this way, the drum shaft (4) is grounded to the drum base (8) via the contact (11), the arm (121), and the ground plate (20). [Effects of the Invention] As described above, according to the present invention, the contact (11) can be pressed against the drum shaft (4) after the earth terminal (1'O) is assembled, and -the contact (1)
Since the arm (121) supporting 1) is made of a material with high bending rigidity, a cylinder unit is obtained in which the earth terminal (10) is easy to handle and assemble. Furthermore, since a mechanism for applying a constant pressing pressure to the contact point of the ground terminal is provided, a cylinder unit that has high resistance to environments such as temperature and is capable of reliable grounding even if the positional accuracy of the ground terminal varies to some extent can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a cylinder unit according to an embodiment of the present invention, and FIG. 2 is a partially sectional side view thereof. Figure 3 is an exploded perspective view of parts near the ground terminal, Figure 4
The figure is a perspective view showing a conventional cylinder unit, and FIG. 5 is a partially sectional side view thereof. In the figure, (4) is a drum shaft, (10) is a ground terminal, (11) is a contact, and (121) is an arm. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) In order to press the contact of the ground terminal against the drum shaft in the ground terminal that grounds the rotating part of the cylinder unit of the rotary head type magnetic recording/reproducing device, the arm that supports the contact is pressed against the drum shaft. What is claimed is: 1. A cylinder unit comprising a rigid body having bending rigidity sufficient to withstand flexural rigidity, and comprising a mechanism for biasing the arm of the cylinder unit. (2) The arm is configured to be rotatable in a direction in which the contact point can freely contact and detach from the drum shaft, and an elastic body is used as a means for biasing the arm. Cylinder unit according to item 1.