GB1561171A - Warning light - Google Patents

Description

(54) WARNING LIGHT (71) We, ROBERT BOSCH GmbH, a German company of 50 Postfach, Stuttgart, Germany., do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention is concerned with warning lights of the type which emit a rotatable light beam in use.

Warning lights of this type (known as rotating indicator lights) are commonly used for marking danger points, especially as a warning to road traffic. Such lights conventionally include a rotatable reflector driven in use by a motor (generally a D.C. motor) which is powered by a battery, preferably a motor vehicle battery. The motor may be connected to the reflector by, for example, a spur gear drive. Since a single stage gearing is desirable in order that the driving means takes up as little space as possible, it is necessary to rotate the motor relatively slowly, for example, at about 2700 r.p.m. A large motor is therefore needed: accordingly, in conventional rotating indicator lights, only about 50% of the volume of the light is available for the optical parts thereof.

We have now developed a warning light of the above-mentioned type having an improved gear drive.

According to the invention, there is provided a warning light which comprises a reflector mounted for rotation in a transparent housing, the reflector being rotatably drivable by an electric motor connected to the reflector by means of a worm gear.

The worm gear in the warning light according to the invention enables the motor to be rotated at a higher speed than in known lights: the motor can therefore be smaller and lighter. This enables more space to be made available for the optical parts of the light without increasing the overall dimensions of the light.

The warning light according to the invention preferably includes a coupling between the motor and the reflector arranged to disengage driving of the reflector by the motor when a predetermined torque is exceeded. A friction coupling mounted between the driven part of the worm gear and the reflector is preferably used for this purpose. Such a coupling can protect the gear drive against mechanical damage, which could be caused, for example, by manual rotation of the reflector during changing of a lamp in the light.

In a preferred embodiment of the invention, the motor is fixed, preferably horizontally, in a recess beneath the housing, the recess being preferably prismatic in shape.

The motor is preferably retained in the recess by a fixing element, such as a tension spring. This arrangement enables the motor to be replaced by a motor which is not quite identical (for example, where difficulties in delivery of replacement motors are experienced).

In order that the invention may be more fully understood, an embodiment thereof will now be described with reference to the accompanying drawings, in which: Figure 1 is a longitudinal (vertical) section of an example of a warning light according to the invention; and Figure 2 is a plan view of the base of the warning light shown in Figure 1, with its transparent housing removed. (The section along the line I-I in Figure 2 corresponds to the section of the base as shown in Figure 1).

Referring to Figure 1, there is shown a warning light having a transparent housing 10, which is generally blue or yellow, releasably mounted on a base 11. A reflector 12 is mounted within the housing 10 for rotation about an incandescent lamp (not shown). The mounting for the reflector 12 comprises a horizontal part 13 and, integral therewith, a downwardly-extending sleevelike part 14. The sleeve-like part 14 fits over a tubular part 15 in engagement therewith so as to form a kind of friction coupling.

Tubular part 15 is driven by an electric motor 16 supplied with DC current.

Between the motor 16 and the reflector 12 there is arranged a gear drive which consists of a worm 17 on the shaft of the motor 16 and a toothed ring 18 on the tubular part 15.

The remaining construction of the warning light base is unimportant to the present invention and will not, therefore, be described in detail. However, it should be noted that the construction not described includes an arrangement for selectively adjusting the inclination of the lower surface of the base relative to its upper surface: a warning light containing such an arrangement is described and claimed in our Patent Application 7944/78 (Serial No. 1561172).

The selective arrangement of two similarly constructed but not identical electric motors 16 and 16' is shown in Figure 2. Each of the motors is mounted in a prismatic recess 19 or 19' in the base 11 wherein the deepest point of the recess 19 or 19' lies below the motor shaft. A tension spring 20 or 20' serves as a fixing element for the motor 16 and by means of which the motor can be pushed into the prismatic recess and be securely retained therein. This arrangement permits a rapid and simple installation of the motor while permitting considerable tolerances as regards the manner of construction and the size of the electric motors used, so that products from different manufacturers can be used when the external dimensions do not vary too greatly from one another.

Because of the greater step-down ratio made possible by the worm gear in the light according to the invention, the motor speed can be doubled relative to the usual arrangements and the motor could thus be substantially reduced in size.

This enables more space to be available for the optical parts of the light: for exam ple up to 75% of the volume of the light can be taken up by the optical parts.

WHAT WE CLAIM IS: 1. A warning light which comprises a reflector mounted for rotation in a transparent housing, the reflector being rotatably drivable by an electric motor connected to the reflector by means of a worm gear.

2. A warning light according to claim 1, which includes a coupling adapted to disengage driving of the reflector by the motor when a predetermined torque is exceeded.

3. A warning light according to claim 2, in which the coupling is a friction coupling between the driven part of the worm gear and the reflector.

4. A warning light according to any of claims 1 to 3, in which the motor is fixed in a recess beneath the housing.

5. A warning light according to claim 4, in which the motor is fixed in the recess by a tension spring.

6. A warning light according to claim 1, substantially as described herein with reference to the accompanying drawings.

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

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. therewith, a downwardly-extending sleevelike part 14. The sleeve-like part 14 fits over a tubular part 15 in engagement therewith so as to form a kind of friction coupling. Tubular part 15 is driven by an electric motor 16 supplied with DC current. Between the motor 16 and the reflector 12 there is arranged a gear drive which consists of a worm 17 on the shaft of the motor 16 and a toothed ring 18 on the tubular part 15. The remaining construction of the warning light base is unimportant to the present invention and will not, therefore, be described in detail. However, it should be noted that the construction not described includes an arrangement for selectively adjusting the inclination of the lower surface of the base relative to its upper surface: a warning light containing such an arrangement is described and claimed in our Patent Application 7944/78 (Serial No. 1561172). The selective arrangement of two similarly constructed but not identical electric motors 16 and 16' is shown in Figure 2. Each of the motors is mounted in a prismatic recess 19 or 19' in the base 11 wherein the deepest point of the recess 19 or 19' lies below the motor shaft. A tension spring 20 or 20' serves as a fixing element for the motor 16 and by means of which the motor can be pushed into the prismatic recess and be securely retained therein. This arrangement permits a rapid and simple installation of the motor while permitting considerable tolerances as regards the manner of construction and the size of the electric motors used, so that products from different manufacturers can be used when the external dimensions do not vary too greatly from one another. Because of the greater step-down ratio made possible by the worm gear in the light according to the invention, the motor speed can be doubled relative to the usual arrangements and the motor could thus be substantially reduced in size. This enables more space to be available for the optical parts of the light: for exam ple up to 75% of the volume of the light can be taken up by the optical parts. WHAT WE CLAIM IS:

1. A warning light which comprises a reflector mounted for rotation in a transparent housing, the reflector being rotatably drivable by an electric motor connected to the reflector by means of a worm gear.

2. A warning light according to claim 1, which includes a coupling adapted to disengage driving of the reflector by the motor when a predetermined torque is exceeded.

3. A warning light according to claim 2, in which the coupling is a friction coupling between the driven part of the worm gear and the reflector.

4. A warning light according to any of claims 1 to 3, in which the motor is fixed in a recess beneath the housing.

5. A warning light according to claim 4, in which the motor is fixed in the recess by a tension spring.

6. A warning light according to claim 1, substantially as described herein with reference to the accompanying drawings.