EP1431998A2

EP1431998A2 - Safety switch device

Info

Publication number: EP1431998A2
Application number: EP03257590A
Authority: EP
Inventors: Xiahong Zha
Original assignee: Positec Power Tools Suzhou Co Ltd
Current assignee: Positec Power Tools Suzhou Co Ltd
Priority date: 2002-12-16
Filing date: 2003-12-02
Publication date: 2004-06-23
Also published as: CN2593341Y; EP1431998A3

Abstract

The present invention relates to a safety switch device comprising a housing and a handle pivotally connected to the housing via a pivot. An electric switch is accommodated within the housing. A safety press-button is slidably provided on the housing. A pressing member is fixedly mounted on a slideable rod in the housing. An internal portion of the handle presses against the slidable rod. The slidable rod lies in a guiding groove on the interior of the housing. A clearance between the slidable rod in the guiding groove and the edge of the guiding groove is sufficient to advantageously permit the slidable rod to swing in the guiding groove when the safety button is not depressed. Irrespective of whether the safety press-button is depressed or not, the handle can always be rotated about the pivot so that the risk of damage by accidental operation of the handle or safety press button is eliminated.

Description

The present invention relates to a safety switch device.
A conventional safety switch device comprises a housing, a handle pivotally connected to the housing via an internal pivot, an electric switch accommodated within the housing, a pressing member in the housing for activating the switch and a safety press-button slidably provided on the housing. The pressing member is fixed on a slideable rod which is inserted in a guiding groove on the interior of the housing. An inner portion of the handle inside the housing presses against the slidable rod. When the safety press-button is not depressed, it presses against the lateral side portion of the inner portion of the handle such that the handle cannot be rotated by the operator (the safety position). When the safety press-button is depressed, it moves apart from the lateral side portion of the inner portion of the handle so that the handle can be rotated about the pivot to cause the inner portion of the handle to press down the slidable rod and cause the pressing member to activate the electric switch (the non-safety position). By wholly constraining the handle in the safety position, there is a risk that the handle and the electric switch may be damaged wholly or partly if the operator forcibly wrenches the handle.
The present invention seeks to ensure that the handle and other components of a safety switch device cannot be damaged when the safety press-button is in a safety position by giving the arrangement for activating the electric switch an additional degree of freedom. In particular, the arrangement for activating the electric switch when the safety press button is in the safety position is free to move non-linearly and when the safety press button is in the non-safety position is free to move linearly only.
Thus viewed from one aspect the present invention provides safety switch device comprising:
a housing;
a slidable rod slidably positioned in a guiding groove in the interior of the housing, wherein a clearance in the guiding groove is sufficient to permit the slidable rod to move non-linearly;
an externally extending handle pivotally mounted on an internal pivot in the housing, wherein an internal part of the handle presses against an end portion of the slidable rod such that rotation of the handle on the internal pivot causes the slidable rod to move;
an electric switch accommodated within the housing;
a pressing member mounted on the slidable rod for activating the electric switch; and
a safety press-button slidably provided on the housing, wherein in a first working position the safety press-button presses against a lateral edge of the slidable rod such that the slidable rod is partially constrained to move linearly and in a second working position the safety press-button is spaced apart from the lateral edge of the slidable rod such that the slidable rod is free to move non-linearly.
The present invention relates to a safety switch device comprising a housing and a handle pivotally connected to the housing via a pivot. An electric switch is accommodated within the housing. A safety press-button is slidably provided on the housing. A pressing member is fixedly mounted on a slideable rod in the housing. An internal portion of the handle presses against the slidable rod. The slidable rod is inserted in a guiding groove on the interior of the housing. A clearance between the slidable rod in the guiding groove and the edge of the guiding groove is sufficient to advantageously permit the slidable rod to swing in the guiding groove when the safety press-button is in the non-depressed state.
The safety press-button has at least two working positions.
(1) In the first working position (non-safety), the safety press-button is depressed and engages the lateral edge of the slidable rod. The handle may be rotated to press down the slidable rod and the safety press-button partially constrains the slidable rod to move linearly and carry the pressing member down to activate the electric switch.
(2) In the second working position (safety), the safety press-button is not depressed and is spaced apart from the lateral edge of the slidable rod. The handle may be rotated to press down the slidable rod and the clearance between the slidable rod and the wall of the guiding groove is enough to permit the slidable rod to swing. In this position, the slidable rod is unable to carry the pressing member to press against and activate the electric switch.
Viewed from a further aspect the present invention provides a safety switch device comprising a housing, a handle pivotally connected to the housing via a pivot, an electric switch accommodated within the housing, a pressure member provided in the housing, a safety press-button slidably provided on the housing, the pressure member fixedly mounted on a slidable rod which is inserted in a guiding groove disposed on the interior of the housing, an inner handle partly composed of a portion of the handle inserted into the housing and pressing against the slidable rod, characterized in that:
a guiding groove clearance enough to permit the slidable rod to swing is provided between the slidable rod in the guiding groove and the side wall of the guiding groove, the safety press-button at least has two working positions, wherein in the first working position the safety press-button presses against the lateral edge portion of the slidable rod and in the second working position the safety press-button is spaced away from the lateral edge portion of the slidable rod.
The present invention will now be described in a non-limitative sense with reference to the accompanying Figures in which:
Figure 1 illustrates a preferred embodiment of the safety switch device of the present invention in a first operating position
Figure 2 illustrates a preferred embodiment of the safety switch device of the present invention in a second operating position;
Figure 3 illustrates a preferred embodiment of the safety switch device of the present invention in a third operating position; and
Figure 4 illustrates in isolation the hosuing and safety press button of the first embodiment; and
Figure 5 illustrates in isolation the safety press button of the first embodiment.
Figures 1-3 illustrate an embodiment of the safety switch device of the present invention in various operating positions and with the cover 40 (see Figure 4) removed for convenience. The safety switch device comprises a housing 9 upon which is mounted (on an internal pivot 2) an externally extending handle 13 and in which is accommodated a pressure activatable electric switch 10. A pressing member 8 is fixed on a slidable rod 12 which is inserted in a guiding groove in the interior of the housing 9. There are clearances 1 and 11 between the slideable rod 12 and the walls of the guiding groove. An engagement surface 5 on an internal portion 6 of the handle 13 presses against a curved surface 4 on an end portion of the slidable rod 12 so as to permit the slidable rod 12 to swing or move linearly (depending on the position of a safety press-button 3 - see below).
The safety press-button 3 is slidably provided on the housing 9 and is shown in isolation in Figures 4 and 5. The safety press-button 3 comprises a main body 42 from which depends an arm 43. The safety press-button 3 has two working positions which advantageously leave the movement of the handle 13 unfettered. In the first working position, the safety press-button 3 is depressed and the arm 43 engages the lateral edge of the slideable rod 12. In the second working position, the safety press-button 3 is not depressed and the arm 43 is spaced apart from the lateral edge of the slideable rod 12. A retaining hook 41 retains the safety press button 3 in the housing 9. With the assistance of the guiding member 14, the safety press-button switches between the first and second press button.
Thus the safety switch device itself has essentially three operating positions.
(1) In the first operating position (see Figure 1), the safety press-button 3 (in its second working position) is not depressed and is spaced apart from the lateral edge of the slideable rod 12 to leave it free to move non-linearly. The handle is lifted upwardly by the operator such that clearances I and 11 between the slideable rod 12 and the walls of the guiding groove permit the slideable rod 12 to swing freely as illustrated. In this first operating position, the pressing member 8 fails to press down and activate the electric switch 10.
(2) In the second operating position (see Figure 2), the safety press-button 3 (in its first working position) is depressed and engages the lateral edge of the slideable rod 12 to constrain it to linear movement. The handle is lifted upwardly by the operator allowing the partially constrained slidable rod 12 to move linearly and carry the pressing member 8 to press down and activate the electric switch 10.
(3) In the third operating position (see Figure 3), the safety press-button 3 (in its second working position) is not depressed and is, spaced apart from the lateral edge of the slideable rod 12. The handle 13 is unmoved. In this third operating position, the pressing member 8 is spaced apart from (and therefore is unable to activate) the electric switch 10.
A spring 7 retains the slideable rod 12 in the guiding groove and generally biases the safety switch device to the third operating position illustrated in Figure 3.

Claims

A safety switch device comprising:

a housing [9];

a slidable rod [12] slidably positioned in a guiding groove in the interior of the housing [9], wherein a clearance [1,11] in the guiding groove is sufficient to permit the slidable rod [12] to move non-linearly;

an externally extending handle [13] pivotally mounted on an internal pivot [2] in the housing [9], wherein an internal part [6] of the handle [13] presses against an end portion of the slidable rod [12] such that rotation of the handle [13] on the internal pivot [2] causes the slidable rod [12] to move;

an electric switch [10] accommodated within the housing [9];

a pressing member [8] mounted on the slidable rod [12] for activating the electric switch [10]; and

a safety press-button [3] slidably provided on the housing [9], wherein in a first working position the safety press-button [3] presses against a lateral edge of the slidable rod [12] such that the slidable rod [12] is partially constrained to move linearly and in a second working position the safety press-button [3] is spaced apart from the lateral edge of the slidable rod [12] such that the slidable rod [12] is free to move non-linearly.
A safety switch device as claimed in claim 1 wherein in a second working position the safety press-button [3] is spaced apart from the lateral edge of the slidable rod [12] such that the slidable rod [12] is free to swing.
A safety switch device as claimed in claim 1 or 2, wherein when the handle [13] rotates a first engagement surface [5] on the end of the internal part of the handle [6] presses against a second engagement surface [4] of the end portion of the slideable rod [12].
A safety switch device as claimed in any preceding claim wherein the pressing member is adapted to activate the electric switch [10] when the slidable rod [12] is partially constrained to move linearly.
A safety switch device as claimed in any preceding claim wherein the pressing member is adapted not to activate the electric switch [10] when the slidable rod [12] is free to move non-linearly.
A safety switch device comprising:

a housing [9];

a slidable rod [12] slidably lies in a guiding groove in the interior of the housing [9];

an externally extending handle [13] pivotally mounted on an internal pivot [2] in the housing [9], wherein an internal part [6] of the handle [13] presses against an end portion of the slidable rod [12] such that rotation of the handle [13] on the internal pivot [2] causes the slidable rod [12] to move;

an electric switch [10] accommodated within the housing [9];

a pressing member [8] mounted on the slidable rod [12] for activating the electric switch [10]; and

a safety press-button [3] slidably provided on the housing [9];

wherein in a first working position at least one side of the safety press-button [3] orientedly presses against a lateral edge of the slidable rod [12] such that the slidable rod [12] is partially constrained to move linearly and in a second working position a sufficient room [1,11] around said slidable rod [12] is provided such that the slidable rod [12] is free to move non-linearly.
A safety switch device as claimed in claim 6, wherein when the handle [13] rotates a first engagement surface [5] on the end of the internal part of the handle [6] slidably presses against a second engagement surface [4] of the end portion of the slidable rod [12].
A safety switch device as claimed in claim 6 or 7, wherein said first engagement surface [5] on the end of the internal part of the handle [6] is a curved surface.