US3258571A

US3258571A - Slide-on lifter for switch blades

Info

Publication number: US3258571A
Application number: US422647A
Authority: US
Inventors: Jr John Schmidt
Original assignee: Guardian Electric Manufacturing Co
Current assignee: Guardian Electric Manufacturing Co
Priority date: 1964-12-31
Filing date: 1964-12-31
Publication date: 1966-06-28
Anticipated expiration: 1983-06-28

Description

June 28, 1966 J. SCHMIDT, JR

SLIDE-ON LIFTER FOR SWITCH BLADES Filed Dec. 31, 1964 United States Patent ration of Illinois Filed Dec. 31, 1964, Ser. No. 422,647 9 Claims. (Cl. 200-166) This invention relates to lifters for movable switch blades, such as, by way of example and not limitation, a conventional switch stack assembly.

Lifters for switch blades are made of various electrically insulating materials such as nylon, fiber, and other suitable materials. For a great many years such lifters have been of conventional form and generally consist of an elongated body of material having a reduced diameter shank portion at one end for insertion through an aperture formed in the movable switch blade. The outer free end of the shank portion is spun over against the outer surface of the blade for securing the lifter thereto. Such forms of lifters and the manner of attachment to switch blades have long presented various problems and are not always eificient, and are either initially or subsequently become defective. When using such conventional lifters it is necessary to preform an aperture in the switch blade for receiving the shank of the lifter to insure that it will be precisely located with respect to the end of the movable blade. Such lifters are employed in a wide variety of switching devices and normally such lifters are engageable by various types of elements such as for example, a bar, a plunger, or a cam for actuating the movable switch blade.

In assembling such conventional lifters to a switch blade, difficulties are frequently experienced in obtaining proper and uniform spinning of the free end portion of the shank of the lifter, due to the flow of material utilized, such as nylon, and which results in a loose or insecure attachment of the lifter to the switch blade and in some instances results in total disconnection of the lifter from the blade while in use. Because of the characteristics and vagaries of the materials used, such as nylon, even when the tooling employed is of correct design and accurately dimensioned, it has not been found possible to consistently obtain a firm, fixed, attachment of the lifter to the blade. Sometimes a lifter when loosely connected to the blade, causes it to assume a cocked position with respect to the blade which causes improper or inefficient operation as a result of engagement with the movable control element which engages the lifter. When a lifter is not adequately and tightly secured to the switch blade, or if it subsequently becomes loose, such a condition results in improper switch adjustment and in some uses it results in inaccurate timing or sequencing operations of electrical circuits.

One of the objects of the present invention is to provide a novel form of lifter and manner of attachment to a movable switch blade which obviates the foregoing difficulties.

Another object is to provide a novel form of lifter and manner of attachment to a movable switch blade so as to preclude any movement of the lifter relative to the blade.

A further object of this invention is to provide a novel form of lifter and manner of attachment to a switch blade and which provides a plurality of separate sets of cooperating abutment surfaces with the blade to preclude movement of the lifter relative to the blade in all directions.

Still another object is to provide a novel form of lifter and manner of attachment to a switch blade which eliminates the necessity for providing a preformed aperture in the blade and which permits quick and easy variation in positioning and securement of the lifter at a desired location on the blade.

Patented June 28, 1966 A still further object of this invention is to provide a novel form of lifter and manner of securement to a movable switch bladewhich is simple in construction and in the manner of application to the blade and which is capable of economical manufacture and assembly to the blade.

Other objects and advantages of this invention will be apparent from the following description taken in connection with the accompanying drawing in which:

FIGS. 1 and 2 are plan and side elevational views of a switch stack assembly wherein the movable switch blade is provided with the lifter embodying the present invention.

FIGS. 3 and 4 are enlarged sectional views through the outer free end portion of the movable switch blade and litter, taken substantially as indicated at lines 33 and 4-4 respectively on FIG. 1.

While the lifter of the present invention may be utilized with a movable switch blade of various types of switch structures, it is herein represented in FIGS. 1 and 2 of the drawing as being embodied in a conventional switch stack assembly. The switch stack assembly comprises main switch blades 10 and 12, between which is mounted a movable switch blade 14. The switch blades 10 and 12 are provided with contact buttons 10a and 12b respectively, selectively engageable by contact buttons 14a and 14b carried on the movable switch blade 14. The

switch blades

10, 12 and 14 are firmly mounted in insulated relation to each other in a stack of blocks 16 of insulating material, and the blocks 16 as well as the corresponding portions of the switch blades are each formed with a pair of longitudinally spaced apart apertures. Tubes of insulating material 18 are press fitted through the assembly of blocks 16, and

switch blades

10, 12 and 14, with said tubes frictionally fitting the apertures of the blocks and the blades and securing them together as a stack, and the tubes serving as an insulating medium for permitting mounting of the switch stack assembly by means of suitable fastening elements. Each of the

switch blades

10, 12 and 14 is formed with an apertured terminal lug 10c, 12c and 140, respectively, extending beyond the blocks 16.

The lifter embodying the present invention and as indicated at 20 is a unitary element molded of electrically insulating material, such as nylon. The lifter includes a body portion 22 formed with a pair of oppositely extending arms 24, each of which arms is formed with an under cut groove 26 defining a passageway 28, dimensioned for a sliding interference fit over the end of the movable switch blade 14. Extending normal to the body 22 is an operating projection 30, the free end of which is adapted for engagement by a movable control element. The body 22 at the side opposite the projection 30 and in alignment therewith is formed with a recess 32.

In attaching'the lifter to the movable switch blade 14, said blade is telescoped into the passageway 28 of the lifter which as above stated provides a slight interference fit and insures a relatively snug engagement of the lifter and blade. When the lifter is positioned in the desired location with respect to the end of the switch blade 14, the material of said blade in registration with the recess 32 is debossed and depressed to form a projecting flange 14d in firm, frictional, engagement with the side walls of the recess 32 as clearly seen in FIGS. 3 and 4 of the drawing. By virtue of the construction of the lifter and the manner of attachment to the movable blade 14, said lifter becomes tightly and firmly secured in a fixed relation to the blade 14. The arrangement is such that there is provided a plurality of separate sets of cooperating abutment surfaces which precludes relative movement of the lifter with respect to the blade in all directions.

As may be seen in FIG. 2 of the drawing, the movable blade 14 in free position has its contact button 14b in engagement with the contact button 12b of the switch blade 12. When the projection 30 of the lifter is engaged by a control element and is raised the circuit completed between contacts 14b and 12b is broken, and a circuit will then be made by engagement of contact 14a of the movable switch blade with the contact 10a of the switch blade 10.

Although I have herein shown and described a preferred embodiment of my invention, manifestly it is capable of modification and rearrangement without departing from the spirit and scope thereof. I do not, therefore, wish to be understood as limiting this invention to the precise embodiment herein disclosed, except as I may be so limited by the appended claims.

I claim:

1. A switch blade formed of a strip of elongated, thin sheet metal and a lifter for said switch blade, said lifter being formed of electrically insulating material and comprising a body formed with a pair of oppositely extending arms and having a passageway for slidably accommodating the switch blade therein, said passageway being dimensioned to provide an interference fit with the thickness and the width of said blade, said lifter having an operating projection connected to said body and adapted for engagement by a movable control member, and cooperating means on said blade and lifter for fixedly securing the lifter on said blade.

2. A switch blade formed of a strip of elongated, thin sheet metal and a lifter for said switch blade, said lifter being formed of electrically insulating material and comprising a body formed with a pair of oppositely extending arms and having a passageway for slidably accommodating the switch blade therein, said passageway being dimensioned for an interference fit with the thickness and the width of said blade, providing a plurality of separate sets of cooperating abutment surfaces for precluding transverse movement of the lifter relative to said switch blades, said lifter having an operating projection connected to said body and adapted for engagement by a movable control member, and cooperating means on said blade and lifter for fixedly securing the lifter on said blade, for precluding longitudinal movement of the lifter relative to said switch blade.

3. A switch blade formed of a strip of elongated, thin sheet metal and a lifter for said switch blade, said lifter being formed of electrically insulating material and comprising a body formed with a pair of oppositely extending arms and having a passageway for slidably accommodating the switch blade therein, said passageway being dimen sioned to provide an interference fit with the thickness and the width of said blade, said lifter having an operating projection connected to said body and adapted for engagement by a movable control member, and cooperating means on said blade and lifter for fixedly securing the lifter on said blade, said cooperating means comprising a recess in the body of the lifter in registration with the blade and said blade having a deformed portion extending into the recess.

4. A switch blade formed of a strip of elongated, thin sheet metal and a lifter for said switch blade, said lifter being formed of electrically insulating material and comprising a body formed with a pair of oppositely extending arms and having a passageway for slidably accommodating the switch blade therein, said passageway being dimensioned to provide an interference fit with the thickness and the width of said blade, said lifter having an operating projection connected to said body and adapted for engagement by a movable control member, and cooperating means on said blade and lifter for fixedly securing the lifter on said blade, said cooperating means comprising a recess in the body of the lifter in registration with the operating projection and with the blade and said blade having a deformed portion extending into the recess.

5. A switch blade formed of a strip of elongated, thin sheet metal and a lifter for said switch blade, said lifter being formed of electrically insulating material and comprising a body formed with a pair of oppositely extending arms and having a passageway for slidably accommodating the switch blade therein, said passageway being dimensioned to provide an interference fit with the thickness and the width of said blade, said lifter having an operating projection connected to said body and adapted for engagement by a movable control member, and cooperating means on said blade and lifter for fixedly securing the lifter on said blade, said cooperating means comprising a cylindrical recess in the body of the lifter in registration with the blade and said blade having a deformed annular portion firmly engaging the wall of the recess.

6. An article of manufacture, a lifter for use with an elongated, thin metal switch blade of rectangular crosssection, said lifter comprising a unitary element molded of electrically insulating material and having a body formed with a pair of oppositely extending arms and a passageway dimensioned for a slight interference fit over the switch blade, and an operating projection connected to and extending in a direction normal to said body.

7. An article of manufacture, a lifter for use with an elongated, thin metal switch blade of rectangular crosssection, said lifter comprising a unitary element molded of electrically insulating material and having a body formed with a pair of oppositely extending arms and a passageway dimensioned for a slight interference fit over the switch blade, and an operating projection connected to and extending in a direction normal to said body, said body being formed with a recess in the side opposite and in registration with said projection and opening into said passageway.

8. A switch blade formed of a strip of elongated, thin sheet metal and a lifter for said switch blade, said lifter being formed of electrically insulating material and comprising a body formed with a pair of oppositely extending arms and having a passageway for slidably accommodating the switch blade therein, said passageway being dimensioned to provide an interference fit with the thickness and the width of said blade for securing the lifter on said blade, said lifter having an operating projection connected to said body and adapted for engagement by a movable control member.

9. A switch blade formed of a strip of elongated, thin sheet metal and a lifter for said switch blade, said lifter being formed of electrically insulating material and comprising a body formed with a pair of oppositely extending arms and having a passageway for slidably accommodating the switch blade therein, said passageway being dimensioned for an interference fit with the thickness and the width of said blade, providing a plurality of separate sets of cooperating abutment surfaces for precluding transverse movement of the lifter relative to said switch blades and for securing the lifter on said blade, said lifter having an operating projection connected to said body and adapted for engagement by a movable control member.

No references cited.

ROBERT K. SCHAEFER, Primary Examiner.

H. O. JONES, Assistant Examiner.

Claims

8. A SWITCH BLADE FORMED OF A STRIP OF ELONGATED, THIN SHEET METAL AND A LIFTER FOR SAID SWITCH BLADE, AND LIFTER BEING FORMED OF ELECTRICALLY INSULATING MATERIAL AND COMPRISING A BODY FORMED WITH A PAIR OF OPPOSITELY EXTENDING ARMS AND HAVING A PASSAGEWAY FOR SLIDABLY ACCOMMODATING THE SWITCH BLADE THEREIN, SAID PASSAGEWAY BEING DIMENSIONED TO PROVIDE AN INTERFERENCE FIT WITH THE THICKNESS AND THE WIDTH OF SAID BLADE FOR SECURING THE LIFTER ON SAID BLADE, SAID LIFTER HAVING AN OPERATING PROJECTION CONNECTED TO SAID BODY AND ADAPTED FOR ENGAGEMENT BY A MOVABLE CONTROL MEMBER.