Power line/transformer switch

A power line/transformer switch of the isolator type, with knife members for the respective phases disposed on a common, rotatable shaft of insulating material. The respective contacts for the knives are disposed on an opposing, fixed shaft composed of insulating material. The respective shafts are mounted at one end of supports that are joined at the opposite end such that the supports constitute the legs of a V-shaped frame. The base of the V-formed supports is disposed perpendicularly on the longitudinal support bar that is parallel with the shafts, this longitudinal bar being provided with fasteners for attachment to a tower.

BACKGROUND OF THE INVENTION 
The present invention relates to an overhead power line/ transformer switch 
of the isolator type having knife-blades for the respective phases, 
Switches on the market today for use on overhead power lines are usually 
based on the use of porcelain insulators (pin- type insulators or massive 
porcelain insulators). These are normally disposed at a 90.degree. angle 
on a shaft. The switch is normally used as an isolating switch, or a 
contact (sweep) is provided in addition for switching unloaded lines or 
unloaded transformers. A load head can also be mounted for switching load 
currents. 
This type of equipment either has limited applicability, or it is 
expensive, because the switch is cumbersome to operate and the contact 
system is not independent of the reaction time of the switch. 
In recent years, remote control of overhead power line networks has become 
more common. Automatic sectional switches have also been installed in the 
network for reducing the interruption intervals, which can be lengthy if 
only one centrally disposed power switch is provided per line. This places 
demands on the switch, which should be operable by means of a relatively 
inexpensive motorized drive means and mechanisms for connecting and 
switching loads. 
BRIEF DESCRIPTION OF THE INVENTION 
This is provided according to the invention with an isolating switch of the 
general type defined above, which is characterized in that the respective 
contacts for the knives of the switch are disposed on an opposing fixed 
shaft composed of insulation material. 
The advantage of this system is that the moment of rotation is reduced 
because the center of rotation is located in closer proximity to the 
center of the shaft. This permits the use of simple rotary means or motor 
drive means. 
The device is also a simpler and lighter weight construction, and it is 
therefore easier to install on the towers or supports for the power lines. 
Another advantage of this switch is that it can be disposed independently 
of direction. Pin-type insulators, for example, cannot be placed 
upside-down.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The switch consists of knives 1 clamped to a rotatable shaft 2, the shaft 
being made of insulating material such as fiberglass-reinforced polyester, 
for example. The shaft 2 may have a cross-sectional configuration as shown 
in FIG. 3. 
The knives 1 cooperate with opposing contacts 3 disposed on a shaft 4 
corresponding to the shaft 2. 
On the shaft 2 and 4 between the respective knives 1 and contacts 3, 
shrink-fitted insulator jackets 6 made of weather resistant plastic or 
rubber material are provided as a safeguard against leaking current. 
The shafts 2 and 4 are mounted on the ends of supports 5 and 10 which are 
joined at the opposite ends thereof so that they form a "V", and the base 
or point of the V is fixedly attached to a longitudinal support bar 11 
which is parallel with the shafts 2 and 4. The longitudinal support bar 11 
is provided with fastening means 9 for attachment to the power line tower 
8. 
The knives 1 are guided into positions of connection or disconnection with 
the contacts by rotating the shaft 2 by means of a manual actuator 
provided at the end 12 of the shaft 2 or by means of a suitable motor 
drive means connected thereto.