US1935029A

US1935029A - Double limit switch

Info

Publication number: US1935029A
Application number: US400084A
Authority: US
Inventors: Malcolm E Henning
Original assignee: Penn Electric Switch Co
Current assignee: Penn Electric Switch Co
Priority date: 1929-10-16
Filing date: 1929-10-16
Publication date: 1933-11-14
Anticipated expiration: 1950-11-14

Description

Nov. 14, 1933. M. E. HENNING 1,935,029

DOUBLE LIMIT SWITCH Filed OCT.. l5,A 1929 MN @www a2,

66 registers with the pin 64, the switch structure is in on position. When either of the cam surfacesy 66h or 66o coact with the pin 64, however, as shown by` dotted lines and when the float shaft 44 is rocked in opposite directions as shown by trical devices for controlling the same depending upon the level of the liquid in the container 5f). The container 50 in the illustration of Figure 1 is a gravity tank the liquid 62 of which is oil to be supplied to a burner. The liquid 62 is supplied to the container 5D from a storage tank 70. A supply pipe '72 leads from a check valve in the bottom of the tank 'l0 to a pump structure '14 connected with the pump motor GB. The discharge of the pump 74 is indicated at 76 and is located within the container .5o whereby oil pumped from the storage tank 70 enters the container' 50.

Practical operation In the operation of my device in the installation illustrated, the switch is shownl in on position so that the pump "1li will be operated by the motor G8 :'or pumping liquid into the container 50. The level oi the liquid will accordingly rise and carry the iioat 56 upwardly with it until the oat engages the collar 5d after which the rod 54 will be raised to the dotted line upper position shown. in Figure `4. This causes the cam member 66 to assume a corresponding position as shown in dotted lines in Figure E so that the cam surface 66h thereof will move the switch arm 20 to oil position as shown in dotted lines. The motor 68 will immediately stop and as the liquid in the container 50 is used, the level thereof will lower until the parts assume the full line posi tion shown in Figure 2. The motor and pump will immediately begin to operate ior again iilling the container lill.

However, if there is no oil in thetanlt 'lo to be pumped into the container 5o, use of the oil from the container 5@ will keep on lowering the level thereof while the pump is operating without drawing any oil into the container 50. When the level o f the liquid 62 consequently reaches a low position as shown by the lower dotted level in Figure 4, the 'float 56 will engage the collar 60 and the weight of the iioat will move the rod 54 downwardly and the arm 52 to its lower dotted position. This causes the cam 66 to be rotated so that the cam surface 66o engages the pin 64 for moving the switch arm to oir position so lthat the pump does not continue to operate indefinitely without any supply oi oil being provided for it.

When the tant: 'lil is again refilled a push button 78 on the switch structure is pushed downwardly to the dotted line position shown in Figure 3 for moving the switch arm 20 to on position. The switch is held in this position until the level oi the liquid 6H is suiilciently high to cause the float titi to float. rlihe push button 78 may then be released and will move upwardly due to a spring il@ thereunder.

The push button 'lll is connected by a rod with an insulating button 84 which engages the bumper spring 38 of the switch arm 20. A sleeve 86 is provided on the lid 12 ofthe switch casing through which the rod 82 is slidably mounted.

Although I have illustrated my double limit switch in connection with a float device so that the switch will be turned off when the level of a liquid lowers to an abnormal position, the cam arm 52 may be connected with any other type of motive device desired, such as a diaphragm so as to control electric devices according to pressure or temperature instead oi liquid level. The illustration in Figure l is merely to show how the device may beapplied to a storage tank and a gravity tank for an oil burner.

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose oi my invention, and it is my intention to cover by my claims, any modified forms of strucn ture or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

l. In an automatic control switch, a movable two position switch member, magnetic means for normally constraining said switch member to one of its positions, a rock shaft, a member thereon of resilient material bent to form a depression and a riser portion on each side of said depression, condition responsive means for automatically rocking said rock shaft, an abutment on said switch arm, said depression and said riser portions being adapted to register' therewith for resiliently operating said switch member to allow it to remain in said mentioned position when the depression registers therewith and to cause it to move to the other of its positions when either of said riser portions register therewith.

2. In a double limit control switch, a movable two position switch member, magnetic means for normally constraining said switch member to one oi. its positions, a rock shaft, a resilient cani lever thereon bent to form a depression and a riser portion on each side of said depression, a single abutment on said switch member, said depression and said riser portions each being adapted to register therewith for operating said switch member to allow it to remain in said mentioned position when the depression registers two position switch member, magnetic means jV for normally constraining said switch member to one oi its positions, a resilient rockable member having a depression and a riser portion on each side ci said depression, an abutment on said ille ill]

switch arm,v said depression and said riser pori 'tions being adapted to register therewith for operating said switch member to allow it to remain in said mentioned position when the depression registers therewith and to cause it to move under the resilient tension of said rockable member to the other of its positions when either of said riser portions register therewith.

MALCOLM E. HENillli i5?.