JPH0647641Y2 - Spindle restraint device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Use of the Invention] The present invention relates to a spindle restraint device for a power tool such as a disc grinder having a split housing structure.

[Background of the invention]

To replace the grindstone or blade with a disc grinder, etc., tighten the wheel nuts that secure the grindstone with two spanners,
I was loosening it. For facilitating the attachment / detachment, as shown in FIG. 3, a system has been devised and implemented in which the lock pin set is engaged with a gear or the like and one spanner set is used. Housing (A) molded of plastics material,
In the case of the split housing structure composed of (B), since the material strength is weak, the lock pin chamber 9b and the bearing chamber 9a are generated by the reaction force of the lock pin group generated when the grindstone is attached and detached.
Of the housing, melting of the housing due to heat generation of the bearing due to the deformation, and a gap between the housings (A) and (B).

[Purpose of device]

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a highly reliable spindle restraint device having a plastic two-part housing.

[Outline of device]

In the present invention, a metal holder is provided to withstand the load applied to the lock pin assembly and to prevent the deformation of the bearing chamber.
Further, the direction of receiving the load applied to the lock pin set is devised so that the component applied in the opening direction of the housings (A) and (B) is reduced.

[Example of device]

An embodiment of the present invention will be described with reference to FIGS. 1 and 2 by taking a split disk grinder as an example. The motor 3, the gear 6 fixed to the spindle 5, the bearing 7, etc. are the housing (A) 1,
It is housed in the housing (B) 2 and is tightened by a screw 17. The grindstone 13 is fixed to the tip of the spindle 5 with a wheel washer 12 and a wheel nut 11. When removing the grindstone 13, push the lock pin set 10 into engagement with the hole 6a provided in the gear 6, fit the pin 14a of the wrench set 14 into the pin hole 11a of the wheel nut 11, and turn the wrench set to turn the wheel nut 11 into place. Loosen and remove whetstone 13. For installation, tighten the wheel nut 11 with the wrench assembly 14 in the same manner. The torque applied to the wrench is quite large, so lock pin set 10
Since the rotation radius is small, the reaction force generated at 10 is 10 times the load applied to the spanner set 14. Since the holder 9 made of a ferrous sintered alloy or the like is provided in the lock pin set 10 and the holding portion of the bearing 8, thermal deformation of the bearing chamber 9a is prevented, and the lock pin set can withstand the reaction force. As shown in Fig. 2, the arm with the thinned portion 9e
Since 9d is provided on both sides of the lock pin chamber 9b, the reaction force direction 18 is applied in the motor axial direction with respect to the housing, so that the problem that the housings (A) and (B) are opened and a gap is generated can be solved. There is also an effect of the heat dissipation plate of the bearing 8 generated during the grinding work with the grindstone. Regarding the positioning of the housings (A) and (B) and the holder 9, the support accuracy is provided by the circular diameter portion of the outer shape portion 9c of the bearing chamber 9a.

In the above embodiment, the disk grinder has been described as an example, but the present invention can also be applied to a power tool having a split housing structure such as a sander circular saw with different attachments and detachments.

[Effect of device]

According to the present invention, since the holder having the lock pin assembly mounting chamber and the arm that receives the reaction force is provided in the bearing portion above the spindle, the lock pin chamber and the bearing chamber are prevented from being damaged and the opening of the housing is reduced. It is possible to provide a highly reliable spindle restraint device.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a spindle portion of a disk grinder in which the present invention is implemented, and FIG. 2 is a sectional view taken along the line AA of FIG. 1 showing a holder and its supporting method of the present invention. FIG. 3 is a vertical sectional view of a spindle portion of a conventional product. In the figure,
1, 2 are housings (A), (B), 5 is a spindle,
6 is a gear, 7 and 8 are bearings, 9 is a holder, 9a is a bearing chamber, 9b
Is the lock pin assembly room, 9c is the outer shape of the bearing room, 9d is the arm, 9e
Is a thickness reduction part, 10 is a lock pin group, 16 is a housing (A),
The ribs and 18 provided in (B) indicate the reaction force direction.

Claims (2)

[Scope of utility model registration request] 1. A motor as a power source, a gear for transmitting the rotation of the motor, a spindle concentrically and integrally rotated with the gear, and a bearing for supporting one end of the spindle.
In a spindle restraint device for an electric tool, wherein a lock pin set engageable with the gear is provided in the vicinity of the bearing, the armature covers the periphery of the bearing and has an arm extending in a direction substantially orthogonal to the spindle. A spindle restraint device characterized in that a metal holder provided with a lock pin chamber having a part of the lock pin set therein is provided. 2. The spindle restraint device according to claim 1, wherein a part of the arm portion is thinned.