Retail Tool Switch Adaptor With Key Lock

Abstract

A safety cover for a toggle switch, comprising a cover mounted over the toggle handle and having mounted thereon a rockable actuator for operating the toggle and locking means for locking the actuator in the "off" position.

Description

BACKGROUND OF THE INVENTION

Devices for locking switches in the inoperative or "lockout" position are known. One type in common use has a face plate which is held in place by the nut which mounts the toggle switch. This face plate has a pair of upstanding flanges with a hole in each flange positioned to receive a padlock when the switch is in the "off" position. In this case, the removing and storing of the padlock each time operation of the switch is desired becomes a problem which is sometimes solved by non-use of the padlock.

Another known lockout is factory assembled on a special switch, this assembly then being factory mounted on the device to be controlled. This assembly requires special provision for assembly and for mounting which is expensive and time-consuming, as well as inappropriate to existing toggle-operated devices already in operation. One version of this type of switch is shown in U.S. Pat. Nos. 3,632,914 and 3,678,229. Other known devices with similar shortcomings to the above include those shown in U.S. Pat. Nos. 3,081,390, 3,217,112 and 3,538,285. All these devices are designed to operate with other than conventional toggle switches and involve relatively expensive fixtures not suitable to solve the problems solved by the instant invention.

SUMMARY OF THE INVENTION

The present-day emphasis on safety has led to concern over the operation of various devices by unauthorized persons, such as children. Underwriters Laboratories, Inc. and the Federal Government, operating under the Occupational Health and Safety Act, have instituted various requirements for things such as power tools and the like. Among these requirements is the capability of denying access to unauthorized personnel.

Some of the solutions to the "lockout" problem have been mentioned above. The first, consisting of "ears" on a face plate, is awkward to use, and uses a padlock which presents a storage problem for the lock itself. In addition, the ears partially surround the operating member of the switch (the toggle arm) making it somewhat more difficult to operate, and even cumbersome.

The second known lockout is expensive, requires special elements, and must be "designed into" the device. In addition, it cannot be adapted to existing units already in operation.

Accordingly, it is an object of the present invention to provide an economical, attractive, permanently fitted safety control for use with toggle switches.

It is another object to provide a convenient, accessible, safe switch operator for use with toggle switches.

It is a more specific object to provide a convenient lockable cover for power tools, including existing tools, that can be installed with a minimum of effort and no modification to the tool, yet provide the maximum in safety and attractiveness.

Other objects and advantages of the invention will become apparent hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of the invention, with the switch unlocked;

FIG. 2 is a sectional view along 2--2 of FIG. 1, with the switch in the "on" position;

FIG. 3 is an exploded sectional view along 2--2 of FIG. 1, showing the switch in the "off-locked" position; and

FIG. 4 is a view along 4--4 of FIG. 2, showing the lock cam surface.

DETAILED DESCRIPTION OF THE INVENTION

This invention may be attached to practically any surface on which a toggle switch may be mounted, but for the purposes of this description it is described as being mounted on a power tool, such as a table saw, or radial arm saw, or the like.

Referring to the drawings, and in particular FIGS. 1, 2 and 3, safety cover assembly 10 is designed to be attached by screws 14 to the surface 12 on which toggle 24 is mounted. The cover 10 is open on its underside. It can be of any desired shape, and is shown here as rectangular.

The cover assembly 10, as seen in FIG. 3, consists of three main elements; a housing 16, a rocker 20, and a lock assembly 40. The housing 16 has an opening 18 in the top for rocker 20. Rocker 20 is pivotally mounted on housing 16 by pin 32, with pin 32 aligned on a vertical plane passing through the center of a switch assembly 24 and perpendicular to a vertical plane marking the path of movement of toggle arm 34. Switch assembly 24 is a common toggle switch with which the present invention is concerned, and is mounted on a tool 12 by nuts 28 on threaded stem portion 30.

In the preferred embodiment as best seen in FIGS. 1, 2 and 3, housing 16 is made roughly rectangular with sloping side walls each having a step or ledge. The bottom of base portion is designed to accommodate different mounting surfaces, such as curved, planar, stepped, etc. The upper walls 38 for enclosing and mounting rocker 20, as well as rocker 20 and the lock assembly 40, to be described later, are of uniform dimensions.

Rocker 20 comprises a pair of exposed upper surfaces 42 and 44 at a slight angle to each other, so that when the switch is in the "on" position, the "off" portion is raised to a prominent position above walls 38. The parallel sides of rocker 20, as best seen in FIGS. 2 and 3, are arcuate. Between these side walls, parallel walls 46 and 48 depend vertically from the underside of surfaces 42 and 44, respectively, in close proximity to toggle arm 34. As rocker 20 is depressed, assuming the assembly to be unlocked, face 46 or face 48 will engage toggle arm 34, urging the switch 26 to the alternative position. In addition, face 50 extends below the arcuate sidewalls to a point where the lower end closely overlies the plane of lock cam 52. As seen in FIG. 3, when the rocker 20 is in the "off" position and lock assembly 40 is in the "locked" position this prevents the switch from being moved to the "on" position until lock assembly 40 is moved to the alternate position, as seen in FIG. 2.

Referring to FIGS. 1 and 3, lock assembly 40, located in a circular stepped bore 54 of housing 16, comprises a shaft 56 with lock cam 52 fixed to the bottom inside housing 16, and spring 58 surrounding a portion of shaft 56 in a counterbore 60. Spring 58 bears against the underside of head portion 62 of shaft 56, biasing lock assembly 40 outwardly, urging lock cam 52 into engagement with the underside of housing 16. The upper surface of lock cam 52, as best seen in FIG. 4, has a pair of small groove means 64 for engaging rounded bosses 66 (see FIG. 3) in the selected positions of the lock assembly. This is to guard against the lock assembly 40 being vibrated out of the selected position. In addition, stop member 68 (see FIGS. 2 and 3) limits the rotation of lock assembly 40 in the locking direction, preventing lock cam 52 from passing beyond registration with face 50.

The embodiment of rocker 20 shown here is a design for maximum economy and strength. As seen in FIGS. 2 and 3, rocker 20 could have been a solid, semi-cylindrical shape with a recess bounded by walls 46 and 48 for reception of toggle arm 34. However, for lightness and ease of manufacture, the embodiment shown is preferred.

This assembly is designed to be installed at the factory, or sold as an attachment to existing tools. In either case, all that is required for a safety lockout is a pair of holes in the sheet metal wall of the tool to receive the mounting screws 14. The assembly comes complete with a key for unlocking and locking the assembly. One form of key 70 is shown in FIG. 2. The assembly is preferably made of high-impact, insulating material, except for the mounting screws and the key which may be made of metal.

Claims

I claim:

1. A safety cover for a toggle switch, comprising a cover adapted to be mounted over the toggle handle and having mounted thereon a rockable actuator with a large, easily contacted surface for contact by an operator, said rockable actuator positively engaging said toggle handle, and a locking means mounted on the safety cover for locking said actuator in a selected position.

2. The safety cover of claim 1 wherein said locking means comprises a rotatable key-operated lever arm assembly engageable with a surface of said actuator when said toggle handle is in the off position.

3. The safety cover of claim 2, wherein said rotatable arm assembly includes detent means for yieldably retaining said assembly in a selected position.

4. The safety cover of claim 1 wherein said cover cooperates with the mounting surface to completely enclose said toggle handle, whereby said switch is operable only by the possessor of said locking means.

5. A power tool having a safety cover for a toggle switch, comprising a cover enclosing the toggle of the tool, said cover having mounted thereon a rockable actuator with a large, easily contacted surface for contact by an operator, said rockable actuator positively engaging said toggle handle, and which has a prominent surface that projects above said cover when the switch is in a first position, and which rocks to a position flush with said cover when the switch is moved to a second position, said cover having a locking means mounted thereon for locking said actuator in said second position.

6. The power tool of claim 5 in which said locking means comprises a rotatable, key-operated lever arm assembly engageable with a surface of said actuator when said actuator is in said second position.

7. The power tool of claim 6 in which said lever arm assembly includes detent means for yieldably retaining said assembly in a selected position.