GB2083292A

GB2083292A - Electric drive apparatus with facility for manual operation

Info

Publication number: GB2083292A
Application number: GB8124277A
Authority: GB
Original assignee: WJ Furse and Co Ltd
Current assignee: WJ Furse and Co Ltd
Priority date: 1980-08-22
Filing date: 1981-08-07
Publication date: 1982-03-17

Abstract

The motor (1) has a drive spindle (2) engageable by the socket end (6) of a bar (5) for manual turning of the spindle by a handwheel (7) in the event of a power failure. The bar is carried in guides (8,9) and biased by a spring (11) away from the spindle. The bar (5) has a collar (12) which actuates a switch (18) as the socket (6) approaches engagement with the spindle to ensure the motor cannot be started by the power supply. As the socket engages the spindle, a further collar (14) engages a brake lever (15) which disengages a brake (25) normally biased to engage and brake the spindle. A knob may replace bar 5. Domestic lift applications are exemplified. <IMAGE>

Description

SPECIFICATION Electric drive apparatus with facility for manual operation The present invention relates to electric drive apparatus, which has a facility for manual operation, for example, in the event of a power failure.

The invention is particularly relevant to lifts having limited space for access such as domestic lifts, e.g. for conveying invalids. If there is a power failure, a person can be trapped between floors or have no means of access to another floor. It is usual, therefore, to provide means for moving the lift manually.

This is done by attaching a handle to the drive spindle of the motor. The apparatus has braking means biased to the braking position and, accordingly, it is necessary to hold off the brake to permit turning of the drive spindle manually. It is difficult for one person to carry out these two operations simultaneously and two people are usually required.

The present invention avoids this problem.

In accordance with this invention, there is provided electric drive apparatus including an electric motor, a drive spindle driven by the motor, braking means, brake-bias means acting to brake the spindle, and manually operable means engageable with the spindle for manual rotation thereof, wherein the manually operable means carries de-activating means, which act against said bias means to release the braking means as the manually operable means engages the spindle.

The bias means may act on the braking means, or on the spindle, or on a member attached to the spindle.

Preferably, switching means is provided actuable to render the motor inoperable, the switching means being positioned so as to be actuated when the manually operable means approaches engagement with the spindle.

Reference is now made to the accompanying drawings, wherein: Figure 1 is a diagrammatic elevation of apparatus according to the invention; and Figure 2 is a detail of a brake arrangement thereof.

Referring to Figs. 1 and 2, there is shown an electric motor 1 mounted on a body 10 and having a drive spindle 2. The spindle drives a shaft 20 by means of a worm gear 21 and a wheel 22. The motor may be housed in a space at the top of a lift shaft and the driven shaft 20 may drive a sprocket engageable with a chain for driving a lift car and its balance weight up and down the lift staft.

The drive spindle 2 has a square-section end part 3 for engagement by a complementary socket 6 in one end of a bar 5. The opposite end of the bar 5 carries a handwheel 7. The socket 6 can be engaged with the square-section end part 3 of the spindle 2 for manual turning of the spindle by means of the handwheel 7.

The bar 6 is guided axially in fixed guides 8, 9 in the body 10 for axial movement between engaged and disengaged positions.

A helical spring 11 engaged between a fixed collar 1 2 and a movable collar 1 3 on the bar, biases the bar to a disengaged position, the movable collar being urged into contact with one of the guides 9.

The spindle 2 has an enlarged diameter portion 2a which is directly braked by brake members 25, 26 carrying brake shoes 25a, 26a which engage this portion 2a. Each brake member 25, 26 is pivoted at 28, 29 on the body 10 and is biased into the braking position by springs 30, 31 acting on the opposite ends. A wedge 33 is movable between these ends to move the members to non-braking positions against the bias of the springs 30, 31. The wedge is magnetically controlled, so that it disengages the brake members only when the motor is energised.

A brake de-activating lever 1 5 is pivoted at 1 6 on the body 10 and has an aperture through which passes the bar 5. The lever 1 5 is gravitationally biased to a non-operative position. The bar 5 carries a flange 1 4 which abuts the lever 15, as the bar is moved into socket engagement with the end part 3 of the spindle 2. This flange moves the lever to a position in which it acts on the wedge 33 to disengage the brake members 25, 26. The arrangement is such that the brake members are not disengaged until the socket 6 fully engages the end 3 of the spindle. The spindle can, therefore, be manually rotated without the necessity for a separate operation to hold the braking members inoperative.

A switch 1 8 is located adjacent the bar 5 and is actuable to switch off the power to the motor 1. A flange 1 2 on the bar actuates the switch 1 8 as the bar approaches the position in which the socket 6 engages the spindle 2.

This ensures that, in the event of a power cut, resupply of power cannot start powered operation of the motor whilst the socket is engaged on the spindle.

It is envisaged that the bar 5 could be completeiy removable from the body 10 instead of being guided. A knob may be provided instead of the bar, the knob having a socket engageable with the end part 3 of the spindle 2. As the knob is engaged on the end part 3 it may engage a lever to actuate a switch to prevent operation of the motor. The spindle may carry a member engageable with braking means and the spindle may be springurged into a brake-engaged position. Pressure on the knob will then act against the bias to move the spindle and lift the member out of engagement with the braking means.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Electric drive apparatus with facility for manual operation The present invention relates to electric drive apparatus, which has a facility for manual operation, for example, in the event of a power failure. The invention is particularly relevant to lifts having limited space for access such as domestic lifts, e.g. for conveying invalids. If there is a power failure, a person can be trapped between floors or have no means of access to another floor. It is usual, therefore, to provide means for moving the lift manually. This is done by attaching a handle to the drive spindle of the motor. The apparatus has braking means biased to the braking position and, accordingly, it is necessary to hold off the brake to permit turning of the drive spindle manually. It is difficult for one person to carry out these two operations simultaneously and two people are usually required. The present invention avoids this problem. In accordance with this invention, there is provided electric drive apparatus including an electric motor, a drive spindle driven by the motor, braking means, brake-bias means acting to brake the spindle, and manually operable means engageable with the spindle for manual rotation thereof, wherein the manually operable means carries de-activating means, which act against said bias means to release the braking means as the manually operable means engages the spindle. The bias means may act on the braking means, or on the spindle, or on a member attached to the spindle. Preferably, switching means is provided actuable to render the motor inoperable, the switching means being positioned so as to be actuated when the manually operable means approaches engagement with the spindle. Reference is now made to the accompanying drawings, wherein: Figure 1 is a diagrammatic elevation of apparatus according to the invention; and Figure 2 is a detail of a brake arrangement thereof. Referring to Figs. 1 and 2, there is shown an electric motor 1 mounted on a body 10 and having a drive spindle 2. The spindle drives a shaft 20 by means of a worm gear 21 and a wheel 22. The motor may be housed in a space at the top of a lift shaft and the driven shaft 20 may drive a sprocket engageable with a chain for driving a lift car and its balance weight up and down the lift staft. The drive spindle 2 has a square-section end part 3 for engagement by a complementary socket 6 in one end of a bar 5. The opposite end of the bar 5 carries a handwheel 7. The socket 6 can be engaged with the square-section end part 3 of the spindle 2 for manual turning of the spindle by means of the handwheel 7. The bar 6 is guided axially in fixed guides 8, 9 in the body 10 for axial movement between engaged and disengaged positions. A helical spring 11 engaged between a fixed collar 1 2 and a movable collar 1 3 on the bar, biases the bar to a disengaged position, the movable collar being urged into contact with one of the guides 9. The spindle 2 has an enlarged diameter portion 2a which is directly braked by brake members 25, 26 carrying brake shoes 25a, 26a which engage this portion 2a. Each brake member 25, 26 is pivoted at 28, 29 on the body 10 and is biased into the braking position by springs 30, 31 acting on the opposite ends. A wedge 33 is movable between these ends to move the members to non-braking positions against the bias of the springs 30, 31. The wedge is magnetically controlled, so that it disengages the brake members only when the motor is energised. A brake de-activating lever 1 5 is pivoted at 1 6 on the body 10 and has an aperture through which passes the bar 5. The lever 1 5 is gravitationally biased to a non-operative position. The bar 5 carries a flange 1 4 which abuts the lever 15, as the bar is moved into socket engagement with the end part 3 of the spindle 2. This flange moves the lever to a position in which it acts on the wedge 33 to disengage the brake members 25, 26. The arrangement is such that the brake members are not disengaged until the socket 6 fully engages the end 3 of the spindle. The spindle can, therefore, be manually rotated without the necessity for a separate operation to hold the braking members inoperative. A switch 1 8 is located adjacent the bar 5 and is actuable to switch off the power to the motor 1. A flange 1 2 on the bar actuates the switch 1 8 as the bar approaches the position in which the socket 6 engages the spindle 2. This ensures that, in the event of a power cut, resupply of power cannot start powered operation of the motor whilst the socket is engaged on the spindle. It is envisaged that the bar 5 could be completeiy removable from the body 10 instead of being guided. A knob may be provided instead of the bar, the knob having a socket engageable with the end part 3 of the spindle 2. As the knob is engaged on the end part 3 it may engage a lever to actuate a switch to prevent operation of the motor. The spindle may carry a member engageable with braking means and the spindle may be springurged into a brake-engaged position. Pressure on the knob will then act against the bias to move the spindle and lift the member out of engagement with the braking means. CLAIMS

1. An electric drive apparatus including an electric motor, a drive spindle driven by the motor, braking means, brake bias means acting to brake the spindle, and manually operable means engageable with the spindle for manual rotation thereof, wherein the manually operable means carries brake de-activating means which act against said bias means to release the braking means as the manually operable means engages the spindle.

2. An electric drive apparatus according to Claim 1, wherein the bias means acts on the braking means.

3. An electric drive apparatus according to Claim 2, wherein the braking means acts directly on the drive spindle.

4. An electric drive apparatus according to Claim 1, wherein the bias means acts on the spindle directly or indirectly.

5. An electric drive apparatus according to any preceding claim including switching means actuable to render the motor inoperable, the switching means being positioned so as to be actuated when the manually operable means approaches engagement with the spindle.

6. An electric drive apparatus according to any preceding claims, wherein the manually operable means is guided for movement into engagement with the spindle and is biased out of engagement.

7. An electric drive apparatus according to Claim 6, as appendant to Claim 5, wherein the manually operable means carries an actuating element for actuating the switching means during said guided movement.

8. An electric drive apparatus according to Claim 5, including a lever for actuating the switching means and biased out of the actuating position, the lever being engageable by the manually operable means.

9. An electric drive apparatus constructed substantially as herein described with reference to the accompanying drawings.