JP319I - Slip ring device for reels - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a slip ring device to be installed on a reel for an electric cord. A reel for an electric cord is composed of a rotating drum for winding up the cord and a bracket, which is a fixed member supporting the shaft of the drum. Since the rotating drum rotates to wind up and unwind the cord, a means for maintaining electrical continuity between the rotating member and the stationary member while rotating relatively is required. Conventionally, as a means for maintaining electrical continuity while rotating, a combination of a slip ring made of a conductive material having a cylindrical surface and a brush that slides against the slip ring has been generally used. However, in the above conventional technology, when the cord has multiple cores, the same number of slip rings and brushes as the number of cores are arranged along the rotating shaft, which increases the length in the axial direction and makes the reel device large as a whole. This disadvantage is particularly noticeable when the number of cores is large and the current carrying capacity is large. However, the technical requirements for reels are often three-core or more, and a current carrying capacity of several amperes or more is required. The present invention has been made in view of the above circumstances, and has as its object to provide a slip ring for a reel that is for use with a multi-core cord, is capable of carrying a relatively large current, and is short in its axial dimension. The basic principle of the present invention is that in order to provide a relatively large sliding area between a rotating conductor and a stationary conductor and to reduce the axial dimension, both sliding members are formed as flat rings, which are alternately stacked in a multi-plate clutch shape with an electrically insulating ring interposed therebetween. In order to achieve the above object based on the above principle, the present invention is characterized in that a plurality of pairs of a flat stationary ring made of an electric conductor and having internal teeth that fit into the spline groove of the stationary shaft and a flat rotating ring made of an electric conductor and having no internal teeth that fit into the spline groove of the stationary shaft are fitted on a stationary shaft with an electric insulating ring loosely fitted on the stationary shaft, and a means for clamping these flat rings in the axial direction of the stationary shaft, and the flat rotating ring made of an electric conductor and having no internal teeth and the flat stationary ring made of an electric conductor and having internal teeth that is stationary with the stationary shaft are made to be electrically conductive for each pair. Next, an embodiment of the present invention will be described with reference to Figs. 1 to 6. Fig. 1 is a cross-sectional view including the axis near the reel slip ring of this embodiment, Fig. 2 is a cross-sectional view taken along the line X-X shown in Fig. 1, and Fig. 3 is an exploded perspective view of the reel slip ring device of this embodiment. This embodiment is an example of a slip ring device for a reel assembled for a three-core cord using members formed for a four-core cord. As shown in FIG.
A stationary shaft 1 having 1c and 1d is formed of an electrically insulating material such as synthetic resin. 2 is a flange-shaped stopper integrally molded near the center of the stationary shaft 1, 3 is a snap ring groove, and 1e is a concentric hollow portion. A flat stationary ring made of a conductive material and having internal teeth that fit into the spline groove of the stationary shaft 1 is formed. This flat stationary ring may be a tongued round washer-like member having at least one internal tooth 4 as shown in FIG. 4. In this embodiment, a copper plate is punched out into a shape with an extended internal tooth as shown in FIG. 5, and is bent as shown in FIG. 6 to form internal teeth 5 at the base portion, and a tip portion 6 is configured to be used as a conductive rod. 6a is a screw hole for connecting electric wires. With the above-mentioned configuration, a notch 7 is formed in the annular portion, but this does not cause any functional problems when used as described below. In this embodiment, three flat stationary rings made of a conductive material (hereinafter referred to as stationary rings) configured as shown in FIG. 6 are provided. For convenience of explanation, these three stationary rings are named stationary rings 8a, 8b, and 8c, respectively. Three flat rotating rings made of a conductive material that do not have internal teeth to fit into the spline grooves of the stationary shaft 1 are configured, and for convenience of explanation, these are named rotating rings 9a, 9b, and 9c, respectively. As shown in Fig. 3, rotating ring 9a is in the form of a round washer having an inner diameter that fits loosely onto stationary shaft 1 and an outer diameter larger than that of stationary ring 8a, and has projections 1 for connecting electric wires on its outer periphery.
The stationary ring 8a is punched from a copper plate and has a screw hole 10a for connecting electric wires. The rotating rings 9b and 9c are constructed in the same manner as the stationary ring 9a. The electrical insulating ring 12 is made of an appropriate insulating material such as synthetic resin.
A round washer-shaped pressure ring 13 having inner and outer diameters approximately equal to those of the rotary rings 9a to 9c is formed of an electrically insulating material such as synthetic resin, and the above-mentioned notches 11, 11 are formed in the pressure ring 13.
The stationary shaft 1 has a spline groove 1a and a spring 16. The stationary shaft 1 has a spline groove 1a and a spring 17. The stationary shaft 1 has a spline groove 1a and a spring 15. The stationary shaft 1 has a spline groove 1a and a spring 17. The stationary shaft 1 has a spline groove 1a and a spring 16. The stationary shaft 1 has a spline groove 1a and a spring 17. The stationary shaft 1 has a spline groove 1a and a spring 17. The stationary shaft 1 has a spline groove 1a and a spring 15 ...
The stationary ring 8a is fitted onto the stationary shaft 1 and abutted against the stopper 2. Next, the rotating ring 9a is fitted onto the stationary shaft 1, and then the electrical insulating ring 12 is fitted onto the stationary shaft 1.
As a result, the stationary ring 8a and the rotating ring 9a come into contact with each other and are fitted onto the stationary shaft. Next, in the same manner as above, the internal teeth of the stationary ring 8b are fitted into the spline grooves 1b, and the stationary ring 8b is fitted onto the stationary shaft 1, and then the rotating ring 9
b. An electrical insulating ring 12 is fitted onto the stationary shaft 1.
The stationary ring 8c and the rotating ring 9c are similarly attached to the stationary shaft 1
The three rotating rings 9a, 9b, and 9c are rotated to align the respective notches 11, and the pressure ring 13 is fitted onto the stationary shaft 1 so that the legs 14 from the pressure ring 13 engage with these notches. A washer 16 and a coil spring 15 are fitted onto the rear of the pressure ring 13, and a snap ring 17 is fixed into the snap ring groove 3. As is clear from the above-mentioned configuration, the three stationary rings 8
Since the internal teeth of each of the first, second and third gears 8a, 8b and 8c are fitted into the spline grooves, their rotation is restricted by the stationary shaft 1.
In addition, the three rotating rings have their legs 14 engaged with the notches 11, so their rotation is restricted by the pressure ring 13. As described above, the stationary shaft 1 is fitted with three pairs, namely, the pair of stationary ring 8a and rotating ring 9a, the pair of stationary ring 8b and rotating ring 9b, and the pair of stationary ring 8c and rotating ring 9c, with the insulating ring 12 interposed therebetween, and is sandwiched between the stopper 2 and the pressure ring 13 and pressed by the coil spring 15. Fig. 1 shows the pair of stationary ring 8b and rotating ring 9b among the three pairs assembled to the stationary shaft 1, with the other two pairs omitted. The stationary shaft 1 is fitted to the drum shaft 18 of the reel device, and is prevented from rotating with respect to the bracket 21 of the reel device by the anti-rotation washer 19 and the mounting screw 20. As a result, the stationary shaft 1 and the stationary rings 8a, 8b, and 8c are fixed to the drum shaft 18.
The tip of the leg 14 engaged with the notch 11 of the rotating ring 9a, 9b, 9c is inserted into the hole 23 formed in the drum 22 of the reel device.
As a result, the pressure ring 13 and the rotating rings 9a, 9b, and 9c are constrained from rotating with respect to the drum 22, and are rotated together with the drum 22 when the drum 22 rotates. Reference numeral 24 denotes a cover shaped to cover the end of the stationary shaft 1, and reference numeral 25 denotes a hole for inserting an electric cord. The cores of a three-core cord 26 wound around the reel drum are inserted into the rotating rings 9a, 9b, and 9c, respectively, as shown in FIG.
c, and each core of the three-core cord 27 on the power supply side of the reel is connected to the tip of the conductive rod portion of the stationary rings 8a, 8b, and 8c. As can be easily understood from FIG. 3, in this embodiment, the stationary shaft 1 is provided with four spline grooves, so that by adding another pair of stationary rings and rotating rings and assembling them, it can be used as a slip ring device for a reel of a four-core cord. Also, by increasing the number of spline grooves provided on the stationary shaft 1 and adding a pair of stationary rings and rotating rings and assembling them through an electrical insulating ring, it can be easily adapted to a multi-core cord of five or more cores. And since the stationary ring and rotating ring in this device are flat, the dimensions in the axial direction can be kept small even if it is configured as a multi-pole type. Moreover, since the stationary ring is in close contact with the rotating ring on its entire side, the current capacity can be made large. Also, if the diameter of the rotating ring is appropriately increased, it can function as a heat dissipation fin and have the effect of preventing the sliding surface from burning. In this embodiment, the sliding area of one pair of the stationary ring and rotating ring is about 2 ^cm2 ,
It was confirmed that a current of 15 amperes could be safely and reliably passed through the slip ring. As described above in detail, by applying the present invention, it is possible to obtain the excellent practical effect of reducing the axial dimension of a slip ring device for a reel for a multi-core cord and increasing the current-carrying capacity.

BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1 to 6 show one embodiment of a slip ring device for a reel according to the present invention, Fig. 1 is a cross-sectional view including the axis, Fig. 2 is a cross-sectional view taken along the line X-X shown in Fig. 1, Fig. 3 is an exploded perspective view,
Fig. 4 is an explanatory diagram of the shape of the stationary ring, Fig. 5 is an explanatory diagram of the punched shape of the stationary ring, and Fig. 6 is a perspective view of the stationary ring. 1... Stationary shaft 1a, 1b, 1c... Spline shaft 2... Stopper, 3... Snap ring groove 4, 5... Internal teeth, 6... Conductive rod portion 6a... Screw hole, 7... Notch 8a, 8b, 8c... Stationary ring 9a, 9b, 9c... Rotating ring 10... Projection, 10a... Screw hole 11... Notch, 12... Electrical insulating ring 13... Pressure ring, 14... Foot 15... Coil spring, 16... Washer 17... Snap ring 18... Reel drum shaft 19... Anti-rotation washer, 20... Mounting screw 21... Bracket, 22... Reel drum 23, 25... Hole, 24... Cover 26, 27... 3-core cord

Claims (1)

[Correction specification] [Utility model registration claims] [Claim 1] A slip ring device for a reel, comprising: a stationary shaft made of an electrical insulator having a spline groove formed therein; multiple pairs of a flat stationary ring made of an electrical conductor and having internal teeth that fit into the spline grooves of the stationary shaft; and a flat rotatable ring made of an electrical conductor and having no internal teeth that fit into the spline grooves of the stationary shaft, fitted onto the stationary shaft via an electrical insulating ring; means for clamping the member fitted onto the stationary shaft in the axial direction of the stationary shaft; and means for restraining the rotation of the flat rotatable ring without internal teeth relative to the reel drum, so that electrical conductivity can be established between each pair of the flat rotatable ring made of an electrical conductor and having no internal teeth that rotates with the reel drum and the flat stationary ring made of an electrical conductor and having internal teeth that is stationary with the stationary shaft.