The present invention is directed to a guard attachment device according to the preamble of claim 1.
A guard attachment device with a fastening element for attaching a guard to a body of a power tool is known, the guard being provided to partially enclose a rotating insertion tool. The fastening element is designed as a loop and connects a fixed spindle support of the power tool in a non-positive manner with a guard spindle support when the loop is tightened around both spindle supports, e.g., using a clamping device that is actuatable using an Allen wrench.
The present invention is directed to a guard attachment device with a fastening element for attaching a guard to a body of a power tool, the guard being provided to partially enclose a rotating insertion tool.
It is provided that the fastening element includes at least one detent element for preventing the guard from rotating relative to the body of a power tool.
A tool-free assembly or adjustment of the guard may be attained when the guard fastening device includes at least one handling element for manually releasing a snap-in connection established via the detent element between the body of the power tool and the guard. In this context, the term “handling element” refers to any manually-operated assembly element, in particular levers and buttons.
It is possible to attain a transfer of force from easily-accessed regions to less easily-accessed regions using a simple design, and to advantageously transfer the force applied by the operator based on the lever principle when the handling element is designed as a lever or at least includes a lever-type extension.
A robust radial fastening with a simple design may be attained when the guard attachment device includes a spindle support mounted on the body of the power tool for radially and axially securing the guard, and when it particuarly advantageously includes a guard spindle support that is provided to establish a plug connection with the spindle support of the power tool.
The ability of the guard to swivel or rotate is not impaired when the guard spindle support and the spindle support have corresponding, cylindrical jacket-shaped surfaces that are suitable for establishing a radially secured, rotatable plug connection between the guard spindle support and the spindle support.
A robust, dust-proof, and cost-favorable rotation lock may be attained when the detent element is designed as a detent cam.
Further cost savings may be attained by simplifying assembly and reducing the large number of components when the detent element is designed as one piece with the handling element, and particularly advantageously when it is designed as a plastic, injection-molded part.
Greater security due to a redundant rotation lock may be ensured by providing at least is two detent elements for preventing the guard from rotating relative to the body of the power tool.
This applies, in particular, when a handling element—that is used to manually release a snap-in connection established by the detent element—is assigned to each of the detent elements. Over-complication of the operation resulting from this duplication may be prevented when the two handling elements or the two engagement points of the handling elements are located directly next to each other, so that the operator need use only one finger to actuate both handling elements.
As an alternative, the two handling elements may be located on opposite sides of the body of the power tool, and they may have opposing directions of actuation, so that the operator need use only the thumb and index finger of one hand, or the thumb and middle finger of one hand for actuation.
Axial fastening may be attained using a simple design with a rearward attachment to axially secure the guard on the body of the power tool.
When the guard attachment device includes a spring element for loading the handling element in the direction of a detent position, it is possible to prevent an accidental release of the detent element or the snap-in connection established by the detent element.
A robust rotation lock may also be realized by designing the detent element to include at least one eccentric cam for establishing the snap-in connection between the guard and the body of the power tool.
A particularly high level of rotation prevention may be ensured by designing the detent element to include toothing that has a matching toothing on the guard.
When the handling element is supported on the body of the power tool such that it may swivel about a swivel axis, support and retention are ensured that have simple designs and are dust-proof.
An associated lever may be designed to extend in the circumferential direction in a space-saving manner when the swivel axis extends at least essentially parallel to a rotation axis of the insertion tool. In this context, “essentially parallel” also refers to a configuration in which the directions of the axes deviate from each other by less than 10°-20°.
As an alternative, it is provided that the swivel axis forms an angle with a rotation axis of the insertion tool. This makes it possible to obtain play for the handling element that is adapted to the particular design.
It is possible to attain a snap-in direction of the handling element and/or detent element that extends transversally to a rotation direction of the insertion tool, in particular a cutting disk, when the swivel axis extends at least essentially perpendicularly to a rotation axis of the insertion tool.
Due to the particularly great risk of the insertion tool shattering when used with this power tool, the improvement in the operational reliability attained via the inventive guard attachment device is particularly effective when the power tool is designed as an angle grinder.
The present invention also relates to a guard for attachment to a body of the power tool, and to its enclosing—at least partially radially—a rotating insertion tool that is insertable in the power tool.
According to the inventive refinement of the guard, it is provided that it includes a detent recess for preventing the guard from rotating relative to the body of the power tool.
According to the inventive refinement of the guard, it is provided that the guard includes a detent recess for preventing the guard from rotating relative to the body of the power tool. Particularly advantageously, the guard has a regular series of detent recesses located equidistantly apart, which detent recesses may also form toothing that continues periodically in the circumferential direction of the guard and/or the guard spindle support.
Further advantages result from the description of the drawing, below. Exemplary embodiments of the present invention are shown in the drawing. The drawing, the description, and the claims contain numerous features in combination. One skilled in the art will also advantageously consider the features individually and combine them to form further reasonable combinations.
Guard 14a protects an operator from injuries that could occur due to pieces flying outwardly in the radial direction that would be produced, in particular, if the insertion tool would shatter. Guard 14a also provides protection against sparks, which may be produced when working with power tool 10a.
To produce a power tool 10a with a guard 14a that is easy to attach and release, and whose rotational position is adaptable to the particular circumstances, fastening element 12a includes at least one detent element 18a for preventing guard 14a from rotating relative to body 16a of power tool 10a.
A tool-free assembly or adjustment of guard 14a is attained by designing the guard fastening device to include a handling element 20a for manually releasing a detent connection established via detent element 18a between body 16a of power tool 10a and guard 14a, handling element 20a being designed as a lever or having two lever-type extensions.
To secure guard 14a radially, the guard attachment device includes a spindle support 22a mounted on a body 16a of power tool 10a, and a guard spindle support 24a, which is provided to establish a plug connection with spindle support 22a of power tool 10a.
A rearward attachment of guard spindle support 24a, which is not shown explicitly here, serves to secure guard 14a axially on body 16a of power tool 10a. The rearward attachment includes openings for the insertion of guard spindle support 24a on tool-side spindle support 22a, and tool-side spindle support 22a has matching openings, thereby ensuring that insertion may take place only in certain relative rotational positions defined by the openings.
In addition, guard spindle support 24a and spindle support 22a have corresponding, cylindrical jacket-shaped surfaces that are suitable for establishing a radially secured, rotatable plug connection between guard spindle support 24a and spindle support 22a.
Detent element 18a is a plastic injection-molded part that is integrally formed as a single piece at one end of one of the lever arms of handling element 20a, and it is designed as a detent cam. As an alternative, detent element 18a may also be designed, e.g., as an aluminum diecast part, or as a punched part.
Spring element 26a, which is designed as a compression spring in the present exemplary embodiment, serves to load handling element 20a in the direction of a detent position.
Handling element 20a is supported on body 16a of power tool 10a such that it may swivel about a swivel axis 28a, which extends parallel to a rotation axis 30a of the insertion tool. In the present exemplary embodiment, swivel axis 28a coincides with a central axis of a screw 32a, with which machine-side spindle support 22a is screwed together with a housing of power tool 10a, which is designed as an angle grinder. In other feasible embodiments of the present invention, swivel axis 28a and the central axis of screw 32a do not coincide.
When detent element 18a has been released, guard spindle support 24a and spindle support 22a or guard 14a and power tool 10a may be rotated in opposing directions, and the matching, cylindrical jacket-shaped surfaces glide over each other, thereby guiding the resultant rotational motion. Detent element 18a also glides over one of the jacket surfaces, until a detent recess 34a is reached, in which detent element 18a engages, driven by the restoring force of spring element 26a.
Handling element 20i includes a button 54i, which is connected with a shaft 44i, for operating the detent device. Handling element 20i is swivelable about a swivel axis 28i defined by shaft 44i, swivel axis 28i forming an angle of 90° relative to a rotation axis 30i of the insertion tool and extending essentially tangentially to spindle support 22i. A detent element 18i is integrally formed with shaft 44i. Detent element 18i may be automatically rotated via a spring element 26i designed as a torsion spring into a detent recess 34i in a guard spindle support 24i. The detent connection therefore remains secure even when very large torques act on guard 141.
Detent element 18l is a ball that moves longitudinally in the direction of a rotation axis of an insertion tool along a path determined by handling element 20l or a wedge surface or a curved surface. When handling element 20l is in the non-actuated position in which it is acted upon by a spring, aforementioned surface locks the ball that has been pushed out on it, so that it engages in corresponding detent recesses 34l in guard spindle support 24l, thereby preventing guard 14l from rotating. The ball is captively supported on power tool 10l, independently of handling element 20l, thereby ensuring that it may not fall out even when guard 14l has been removed.
To enable guard to freewheel, ring 52n is displaced manually against a spring element 26n, thereby disengaging detent elements 18n. Guard 14n may then be rotated, in accordance with the distribution of the teeth. When spring element 26n is released, possibly in conjunction with a slight rotational motion of guard 14n, detent elements 18n engage once more. In the direction of action of spring element 26n, ring 52n is captively held on spindle support 22n by a not-shown stop. Suitable bevels provided on detent elements 18n may simplify automatic engagement.
In addition to compression springs, any types of springs that appear suitable to one skilled in the technical art may be used as spring elements, e.g., leaf springs, leg springs, coiled springs, or torsion bar springs.
Number | Date | Country | Kind |
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10 2006 027 576 | Jun 2006 | DE | national |
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WO2007/144219 | 12/21/2007 | WO | A |
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