Dec. 10, 1946. R ,_, WlLUAMS 2,412,377 BALANCED PRESSURE SWITCH Filed March 24, 1944_ Q3 24 IN VEN TOR. 34 Fag/Wand A k/d/Mm BY Patented Dec. 10, 1946 2,412,377 UNITED STATES PATENT OFFICE 2,412,377 BALANCED PRESSURE SWITCH Raymond L. Wiiliams, Arcadia, Calif. Application March 24, 1944, Serial No. 527,875 2 Claims. (01. 200——S3) 1 This invention relates to certain new and use-1 ful improvements in balanced pressure switches and has for its principal object the provision of 2 boss l3 having a threaded opening it formed therein to which is connected a conduit leading from a welding cylinder (not shown)_ for the an improved construction of the character here admission of air therefrom into a chamber A inafter described, which will be highly efficient hereinafter described. This threaded opening in use and economical in manufacture. 14, at its inner end portion, terminates in a counterbore 15 which in turn communicates pneumatic The present systems invention where isit designed is desirable for for use ef~ with the chamber A. This chamber A is provided fective operation of the system that the pressure by the end wall ii and a diaphragm I5 formed be completely stabilized throughout the system. 10 of suitable material, such for example as stain The balanced pressure switch constituting the less steel. Mounted in the counterbore between subject matter of my invention has been espe the boss i3 and the diaphragm I8 is a compres cially designed for use in connection with pneu sion spring M. This end wall H and the dia matic welding machines and is to take the place phragm I 6 are connected to the intermediate of the pressure gauge usually employed in such 15 portion Hi’ through the medium of bolts [3 machines, which gauges are manually set to threaded into openings l9. maintain a stabilized pressure in the system. Adjustably carried by the diaphragm i6 is \a Many attempts have been made to provide a threaded stud 2i! having a disc-shaped head 21! means, for this purpose, which is automatic in its formed on one end portion thereof. This stud operation but prior to the advent of my balanced 20 2D is threaded through nuts 22, and the end 23 pressure switch these various means have proven thereof has a screwdriver slot 24 formed therein unsatisfactory, unreliable, and costly in manu whereby when the lock nut 25 is loosened the facture. It therefore was one of the principal stud 20 may be adjusted relative to the mounting objects of this invention to provide a pressure nuts 22. switch which would be automatic in its opera 25 The wall 12 carries a plug housing 26 into tion; one which would become effective for its which an ordinary standard electric plug (not intended purpose only upon a stabilized pressure shown) is adapted to be mounted for connection in the pneumatic system whereby the pressure with terminal posts 21 carried by the end wall switch of my device, when operated by a bal as shown. These terminal posts 2‘! are connected anced pressure, would be positive in its opera 30 to an electric switch 28 through the medium of tion to set into circuit such of the mechanism conductor wires 29. This switch 28 is carried as required for effective operation of the pneu in any suitable manner by the wall l2, such for matic system; and a balanced pressure switch example by means of screws 30. This switch 28 which would be reliable and yet economical in constitutes no part of the present invention and manufacture. is preferably of a structure substantially similar Other objects will appear hereinafter. to that shown in U. S. Patent No. 2,289,108 The invention consists in the novel combina granted July '7, 1942, to one Eaton. As shown tion and arrangement of parts to be hereinafter in the drawing accompanying this application, described and claimed. this switch comprises a sleeve 3! through which The invention will be best understood by ref a push rod 32 operates, the push rod 32 serving erence to the accompanying drawing showing to operate the switch elements (not shown) illus the preferred form of construction, and in which: trated in the patent hereinbefore referred to. Fig. 1 is a sectional detail View of the balanced This push rod 32 is disposed in the path of move pressure switch embodied in my invention; and ment of the stud 20 when the stud 20 is moved Fig. 2 is a vertical sectional detail View taken longitudinally in a manner hereinafter described. substantially on line 2—2 of Fig. 1. This end wall i2 is connected to the intermediate When the balanced pressure switch, herein housing portion l6’ through the medium of bolts after described, is used in a pneumatically oper~ 33 threaded into the openings l9. ated resistance welding machine of a construc To complete the invention, I provide on the tion and type well-known in the art, it will serve 50 intermediate portion ill’, mounting lugs 34 which to assure that the pressure on the electrodes is completely stabilized. This pressure switch com facilitate mounting the pressure-operated switch on a, ?xed object. In the intermediate portion prises a housing [9 having a cylindrical inter H)’ of the housing [0 there is provided an open mediate portion I 0’, and end walls H and I2. ing 35 in which is mounted a conduit leading The end wall ll comprises a centrally located 55 from a pressure check valve (not shown) which 2,412,377 3 1% in turn communicates with a pressure generating device of a standard equipment used in connec spirit of the invention. I, therefore, do not wish tion with pneumatically operated resistance weld ing machines. My improved balanced pressure switch operates as follows: The proper pressure to effectively operate a to be limited to the precise details of construc tion set forth, but desire to avail myself of such variations and modi?cations as come within the scope of the appended claims. Having thus described my invention, what I claim as new and desire to protect by Letters Pat pneumatically operated resistance welding ma ent is: 1. A pressure balanced switch comprising a chine is admitted into the chamber B through the Opening by a pressure check valve (not 10 housing, a diaphragm in the housing dividing the same into opposed non-communicating cham shown) functioning to assure the admission of the proper degree of pressure into this chamber. When the pressure in the chamber B reaches the proper degree, the diaphragm will be caused bers, a switch in one of said members and com prising a, push rod, means carried by the dia phragm and adapted to engage the push rod for to ?ex outwardly therefrom, This ?exing of the 15 moving the same in a direction to close said diaphragm I6 will permit the switch 28 to open. switch when the air pressure in one of saidcham hers is greater than the air pressure in the other The operator or” the welding machine admits air of said chambers, means for admitting air under into the welding cylinder (not shown) and when pressure to each of said chambers, and means the pressure of this air has been built up in this welding cylinder to a point for proper welding 20 carried by said housing and engaging said dia phragm for maintaining said diaphragm in an operation, which is greater than the pressure un?exed position when the air pressure in each of the air in chamber B, the air pressure in of said chambers is equal. chamber A from this welding cylinderwill ?ex 2. A pressure balanced switch comprising a the diaphragm l6 in an opposite direction, clos housing, a diaphragm in the housing dividing the ing the switch 28. So long as this proper air same into opposed non-communicating cham pressure is maintained in chamber .A, the switch 28 will remain closed and the welding machine bers, a switch in one of said chambers and com prising a push rod, means carried by the dia properly operated by a stabilized air pressure through its pneumatic system. The spring I? phragm and adapted to engage the push rod for functions to return the diaphragm IE to its nor 30 moving the same in a direction to close said mal unflexed position when the air pressure is switch when the air pressure in one of said chambers is greater than the air pressure in the equal in both chambers A and B. As previously pointed out, with a balanced pressure switch con other of said chambers, means for admitting air under pressure to each of said chambers, and’ structed in the manner hereinbefore described, the pneumatic system of a pneumatically oper- ; means carried by said housing and engaging said diaphragm for maintaining said diaphragm in 'ated resistance welding machine will be stabi lized during its operative period to assure proper \ an un?exed position when the air pressure in :and effective welding operation. each of said chambers is equal, said last-named While I have illustrated and described the pre ferred form of construction for carrying my in vention into e?ect, this is capable of variation means comprising a spring arranged between a :and modi?cation without departing from the wall of said housing and said diaphragm. RAYMOND L. WILLIAMS.