JP2517034Y2 - Belt type grinding tool - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a belt-type grinding tool provided with an endless grinding belt which is tensioned by a pair of idle pulleys and drive pulleys, and in particular, the wearing of the grinding belt or The present invention relates to a belt-type grinding tool capable of changing the grinding belt from a tension state to a relaxation state when detaching.

[Prior art]

The cloth or paper endless grinding belt is manufactured to a certain standard size, but is stretched under tension with a pair of pulleys because it may stretch during use. Therefore, when exchanging the grinding belt, it is necessary to loosen the tension state. In such a case, a device capable of loosening the grinding belt is disclosed, for example, in Japanese Utility Model Publication No. 48-34080. That is, the disclosed invention has a structure in which when the grinding belt is replaced, the tension lever for supporting the idle pulley is locked at the position pushed into the tool housing by using the locking lever.

[Problems to be solved by the device]

However, in such a conventional structure, it is unavoidable that the locking lever projects from the side of the housing.
On the side of a wall or in a narrow place, this locking lever is a hindrance to the work, and moreover, this locking lever is apt to be deformed or damaged when it receives an impact force.

An object of the present invention is to prevent a mechanism for changing an endless grinding belt stretched around an idle pulley and a drive pulley from a tensioned state to a relaxed state so as not to disturb the grinding work and to be damaged by contact with the surroundings. It is to provide a belt-type grinding tool that eliminates the above problems, and this is a problem to be solved by the invention.

[Means for solving the problem]

As a means for solving the above-mentioned problems, a belt-type grinding tool of the present invention has a drive pulley in a handle portion, and a tension bar is elastically urged in a forward direction in a bracket provided on the tip side of the handle portion. Endless grinding belt is stretched over the idle pulley and the drive pulley provided at the tip of the tension bar, and the shoe is slidably contacting the inner surface of the endless grinding belt in parallel with the grinding belt. For the belt type grinding tool in which the base end of the guide is fixed to the bracket, the free end of the shoe guide is formed with a hook protruding toward the tension bar and slidably contacting the surface of the tension bar. Then, at the position where the tension bar is retracted by a predetermined amount against the elastic force while the endless grinding belt is stretched, the tension bar is stretched. And fitted into sliding contact with the bar surface hook, adopts a structure forming a concave shaped engaging part for preventing the backward movement of the advancing direction of the tension bar, it is to achieve the intended purpose.

[Action]

The shoe guide that supports the back surface of the grinding part of the grinding belt normally supports the grinding belt without any change from the conventional shoe guide.However, when replacing the grinding belt, the tension bar acts in the axial direction. When pushed in against the elastic force, the hook formed at the front free end of the shoe guide engages and is fixed to the locking portion formed at the front of the tension bar. At this time, the grinding belt is maintained in a relaxed state, so that the grinding belt can be easily replaced. The tension bar locking means overlaps the back surface of the grinding belt during the grinding operation and does not project to the side surface of the grinding belt.

〔Example〕

Reference numeral 1 denotes a handle portion which incorporates a motor (not shown), and the rotation of the motor is transmitted to the rotary shaft 3 via an orthogonal transmission mechanism such as a bevel gear pair. A drive pulley 5 is fixed to the rotary shaft 3, and the pulley 5 is provided so as to project from the handle portion 1. The outer peripheral surface portion is uniformly protected by a bracket 7 that is provided in series toward the front of the handle portion.

Reference numeral 9 is an idle pulley axially supported by a holder 11, 13 is a tension bar, and the holder 11 is attached to the tip end portion of the tension bar 13. The base end portion of the tension bar 13 is bored in the bracket 7 in the axial direction. The tension bar 13 is elastically urged forward by a compression coil spring 17 arranged in the inner portion of the hole 15. At the tip of the bracket 7, symmetrically about the axis,
Further, the sleeve 19 having the pair of split grooves 19A, 19A formed in the axial direction is fixed, and the pin 21 fitted into the split grooves 19A, 19A of the sleeve 19 is slightly projected in the diametrical direction of the tension bar 13 to be fitted. The tension bar 13 is prevented from rotating by being fitted and fitted into the split grooves 19A, 19A, and is supported so as to be movable back and forth only in its axial direction.

The holder 11 is rotatably attached to the tip end of the tension bar 13 by a pivot 22 as shown in FIG. That is, a stepped space 23 is provided between the base of the holder 11 and the tension bar 13, the compression coil spring 25 is interposed in the space, and the stepped space 23 is fixed. Then, by screwing the screw 29 through the holder 11, the tension bar 13 can be pressed by the tip of the stop screw 29, and by tightening and tightening the screw 29,
The drive pulley 3 and the idle pulley 9 are configured so that the axes thereof can always be maintained in parallel.

Reference numeral 31 is an endless grinding belt stretched between the idle pulley 9 and the drive pulley 5, and it is well known that the elastic force of the compression coil spring 17 gives a tension force. By pressing the tension bar 13 in the direction of its base against the elastic force of the compression coil spring 17, the tension bar 13 can be retracted together with the holder 11 to be in a relaxed state. The point is no different from the conventional belt type grinding tool.

Reference numeral 33 denotes a shoe guide provided on the inner surface side of the grinding position of the endless grinding belt 31 and having the same width as the width of the endless grinding belt 31, but formed by a strip-shaped spring steel plate having a slightly wide width and relatively high rigidity. Has been done. Only the base end of the shoe guide 33 is fixed to the bracket 7 provided at the front of the handle portion 1 with a screw 35, and the free end thereof is bent upward in an L shape to form a hook 33A. ing. In FIG. 1, 13A is a right-angled locking portion formed on the tip end surface of the tension bar 13, and 13B is a reverse trapezoidal locking groove formed on the lower surface of the tension bar 13 in close proximity to the right-angled locking portion 13A. The hook 33A serves as a locking portion that locks the tip of the tension bar 13 when the tension bar 13 is retracted against the elastic force of the compression coil spring 17, as shown in FIG. It has a function of preventing the tension bar 13 from coming off when the endless grinding belt is cut and when the belt is replaced. Therefore, when the belt-type grinding tool of the present invention is in a usable state, the hook 33A is in the engaging groove portion 13B and the shoe guide 33 is in the grinding belt 31.
1 is pressed in the direction of arrow R in FIG. 1 against the elastic force by the tension force in the centripetal direction, and when the right angle locking portion 13A of the tension bar 13 faces the hook 33A of the shoe guide 33, The elastic force of the shoe guide 33 causes the hook 33A to automatically engage with the right-angle engaging portion 13A to maintain this state. The engaging groove portion 13B is formed in an inverted trapezoidal shape because the hook 33A is engaged with the engaging groove portion 1 when the tension bar 13 is axially pressed.
This is because the front wall surface is an inclined surface in order to easily escape from 3B.

33B is an operation piece that is integrally formed with the shoe guide 33 by standing up on both sides of the tension bar 13 in an L shape. The hook 33A of the shoe guide 33 is a right-angled portion 13A of the tip end of the tension bar 13.
It is for detaching the hook 33A from the hook 33A when the hook 33A is locked, and the operation piece 33B can be pinched with a fingertip.

 Next, the operation of the embodiment will be described.

When the endless grinding belt 31 is replaced, in the state shown in FIG. 1, the idle pulley 9 is pushed to the right in the figure to retract the tension bar 13 in its axial direction, and the right angle engaging portion 13A of the bar 13 is attached to the shoe guide. When the push-in of the tensioner 13 is stopped at a position beyond the hook 33A of the 33, the elasticity of the shoe guide 33 causes the hook 33A to move to the inclined surface portion 13 of the engaging groove portion 13B.
After overcoming C, the tension bar 13 is locked to the right angle locking portion 13A, whereby the endless grinding belt 31 is maintained in a loose state (Fig. 3). In this state, the endless grinding belt 31 is removed from the drive pulley 5 and the idle pulley 9 and replaced with a new one. After replacing the endless grinding belt, pinch the operation piece 33B with your fingertip and push it down, and the hook 3
Since 3A is easily disengaged from the right-angled locking portion 13A of the tension bar 13, the tension bar 13 is returned to the free state by the action of the compression coil spring 17, and the endless grinding belt 31 is tensioned.

The present invention has been described above in detail based on the embodiments, but it goes without saying that the present invention can be variously modified without departing from the gist thereof.

[Effect of device]

Since the belt-type grinding tool of the present invention is provided with a hook for locking the tension bar at the free end of the shoe guide and elastically locks the tension bar with this hook, The grinding belt can be easily attached and detached at the time of mounting and removal. Moreover, since the locking means of the tension bar is constituted by the tension bar and the shoe guide, and the free end of the shoe guide is engaged with and disengaged from the lower surface of the tension bar, this locking means can be used for grinding work. Since there is no hindrance and there is no contact with surrounding objects, there is no possibility of damage to the locking means, and the service life of the belt-type grinding tool can be significantly extended.

[Brief description of drawings]

FIG. 1 shows an embodiment of a belt type grinding tool according to the present invention. FIG. 1 is a vertical sectional side view of a main part of a bracket cover cut away, and FIG. FIG. 3 is a plan sectional view of the same taken along the center, and FIG. 3 is a side view showing a relaxed state of the belt with the tension bar locked. 1 ... Handle, 5 ... Drive pulley, 7 ... Bracket, 9 ... Idle pulley, 13 ... Tension bar, 13
A: right angle locking part, 13B: reverse trapezoidal locking groove part, 13C: slope part, 17: compression coil spring, 31: endless grinding belt, 33: shoe guide, 33A: hook.

Claims (1)

(57) [Scope of utility model registration request] 1. A grip having a drive pulley, a tension bar elastically urged in an advancing direction in a bracket provided on the tip side of the grip so as to be able to move forward and backward, and provided at the tip of the tension bar. An endless grinding belt is stretched between the idle pulley and the drive pulley, and the base end of the shoe guide that slides in parallel with the grinding belt on the inner surface of the endless grinding belt is fixed to the bracket. A tool, wherein the free end of the shoe guide is
A hook having a shape protruding toward the tension bar and slidingly contacting the surface of the tension bar is formed, and the tension bar resists elastic force while the endless grinding belt is stretched on the tension bar. A belt-type grinding tool in which a hook that slidably contacts the surface of the tension bar is fitted at a position retracted by a predetermined amount to form a recessed locking portion that prevents the tension bar from returning in the advancing direction.