From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Datasheet describing the mechanical features of the Burgess Micro Switch.
| Identifier | ExFiles\Box 168a\2\ img244 | |
| Date | 1st January 1936 | |
| Mechanical Features of the Burgess Micro Switch 1/1000 Inch Button Movement The Burgess Micro Switch operates with a snap action when the actuating plunger is depressed to a given point and returns with a snap to its normal position when the plunger is allowed to return 1/1000 of an inch toward its normal position. The maintained contact type Micro Switch does not have the spring return action and must be reset after the mechanism has been tripped. This switch requires a motion of 5/1000 inch to reset the contacts. 4 Ounces Differential Pressure The initial pressure necessary to close the average Micro Switch is 14 ounces, but, due to unavoidable variations in spring materials, it will vary between 10 and 18 ounces. Upon releasing the pressure, the switch will return with a snap to its normal position when the pressure is reduced approximately 4 ounces. Preloading is recommended only in case of relatively light electrical loads. At a small extra charge, switches can be provided for any initial pressure between 7 and 18 ounces, with a tolerance of 3 ounces between switches. Light, Compact, and Easy to Mount The Micro Switch weighs but one ounce and is remarkably small for its high rating at line voltage. Hence, it fits into many places where space and weight are at a premium. The smooth, level sides of the switch permit mounting on any flat surface or on bosses by means of two No. 6 machine screws. Up to 250 volts the Bakelite housing provides Underwriters' over-surface distance to ground. Above 250 volts, insulating mounting is recommended. The rigid mounting of the Micro Switch assures permanence of adjustment on sensitive applications. There are no moving flexible leads to upset calibration or break with wear. Operates in Any Position Since gravity or ordinary vibrations do not affect the accurate operation of the Burgess Micro Switch, it can be mounted in any position on vibrating machinery. Where severe vibration is encountered, special high pressure switches are available. Burgess engineers should be consulted on all such jobs. Rugged Mechanism and Housing Only metal and molded plastics are used in the Burgess Micro Switch. It is practically impossible to damage the switch by ordinary usage. The chromium plated, hardened steel plunger is set in a sturdy Bakelite button head, which bears against a positive stop before damage can be done to the operating spring. The switch will withstand a steady pressure of 50 pounds on the plunger or a blow from a one pound weight dropped one inch. Where constant excessive pressures are encountered, a spring take-up mechanism can be easily applied. Write for bulletin “How to Use the Burgess Micro Switch,” or submit your problem. Long Trouble-Free Life Special care has been taken to insure long life in the Micro Switch. The spring is of beryllium copper specially heat treated to give greatest flexure life. Movement of the operating plunger against the spring is limited by a rigid stop to 11/1000 of an inch. For many applications this affords ample protection against over-stressing. On high speed applications, however, where life in excess of one million operations is required, it is well to so limit the travel of the actuating mechanism that the Micro Switch plunger will not be depressed more than 5/1000 of an inch beyond the point at which the switch operates. Burgess engineers will gladly provide general suggestions on over-travel limits and recommendations on individual problems. Dust-Proof Construction The Bakelite housing of the Burgess Micro Switch provides a sealed, dust-proof enclosure, which is a guarantee against failure due to the presence of dust, dirt, oil, moisture, and corrosive fumes. Rapid Snap Action Positive snap action with no neutral position insures freedom from radio interference. At its rated current capacity, the switch can be operated up to 60 times per minute. Higher speeds are possible in applications involving smaller currents. Write for detailed recommendations on your specific problems. Copyright 1936, by C.F. Burgess Labs., Inc. BURGESS | ||