US2191335A - Electric switch control means - Google Patents

Description

Feb. 20, 1940. A. BINNS ELECTRIC SWITCH CONTROL MEANS Filed Sept. 26, 1938 3 Sheets-Sheet l Feb. 20, 1940. g s

ELECTRIC SWITCH CONTROL MEANS Filed Sept. 26, 1938 3 Sheets-Sheet 2 Feb. 20, 1940. A. BINNS ELECTRIC SWITCH CONTROL MEANS Filed Sept. 26, 1938 3 Sheets-Sheet 3 f: & Q

Patented Feb. 20, 1940 2,191,335

UNITED STATES PATENT OFFICE ELECTRIC SWITCH CONTROL IVLEANS Arthur Binns, Soho Foundry, Birmingham, England, assignor to W. & T. Avery Limited, Soho Foundry, Birmingham, England Application September 26, 1938, Serial No. 231,741 In Great Britain September 30, 1937 2 Claims. (Cl. 200-52) This invention has reference to improvements making position (Figure 2) under the action of relating to electric switch control means particugravity. This lever 5 is fulcrumed on the pin 6 larly for use with weighing mechanism, the inand is connected intermediate its ends by means vention having for its primary object the proviof a pin 1 to the lower end of the moving core 5 sion of an improved electric switch control unit armature 3 of an electro-magnet 9 which is in- 5 which is simple and effective in operation and corporated in the aforesaid circuit through the which capable of being adapted for the control tiltable mercury switch 4 by means of the leads of a wide variety of electrically operator auxiliary 9*, so that whenever the switch 4 completes the apparatus employed in conjunction with weighing Cl'lFCUit the electro-magnfit 9 is energised, and

10 mechanism. tends to cause the armature 8 through the lever 10 The invention consists of an improved electric 5 to restore the switch 4 to the circuit breaking switch control means wherein the electric switch lws ti n $6611 in Figure The m-ma t is associated with a member which normally tends it operates with a time lag in order to ensure the to move the switch to the circuit making position efficient operation of the several components of 16 and wherein the completion of the circuit by the the control means as will appear fr0m t Stateswitch energises an electro-magnetic device which ment of operation of the invention which follows tends to influence the said member so as to n e p fic restore the switch to the circuit breaking position, The switch-carrying lever 5 is provided interand wherein the actuation of the said member mediate its ends with an outwardly cranked plate 20 to move the switch to one or other of the aforeiii carrying a pin Mi on which is mounted a 20 said positions is restrained by locking devices one roller II. This roller is adapted to co-operate or other of which is moved out of the looking with two levers l2 and 13 respectively the lever I2 position as required by a movable element assois fulcrumed on the pin H and is counterciated with the mechanism which is required to weighted by means of the weight 12* and is so be controlled by the switch. positioned that the arm l2 of this lever normally 25 The invention further resides in the details of supports the roller II as seen in Figure 1, thereby construction of the improved switch control maintaining the switch carrying lever 5 in the mechanism to be described hereinafter. raised position seen in this figure. The lever l3 A preferred embodiment of the present invenis fulcrumed on the pin l3 and is formed as a tion will now be described in its application to a bell-crank the arm I3 thereof is adapted to bear 30 switch control mechanism for the electrically against the said roller H and constitutes a holdoperated totalising apparatus for use with weighing-down device for the switch-carrying lever 5 ing mechanism as described in the specification when this lever is tipped to its lowest position as of patent application Serial No. 104,249 dated seen in Figure 2 as will be hereinafter explained. 035013161 6, 1935- A fixed stop M is provided to limit the upward The invention is illustrated by the accompanyoti of th lever 55, while a fixed stop i5 is ing drawings, wherein similar reference numerals pyovjded to 1mm t downward motign of t indicate similar parts in the several views. lever 53 and adjustame stops 9 55s are provided Figure l is a front devotion of the mechanism the stop it serving tolimit the upward motion of comprising the 331F856? invention Showing the the lever i2, and the stop 16* the downward mo- 40 parts in the position occupied when the circuit ti n of th l er l3,

hr u h h l ri llywp ra totalisins ppa- Mounted on the Weighing lever I? are a pair of ratus is broken, adjustable stops !8, 18 the stop l8 being asso- Figure 2 s a Similar elevation to that Seen in ciated with the resilient spring plate I9 which is Figure l, but il istrates the position of the parts e ured at e nd to the lever ll. 45

when the circuit through the electrically oper- The operation of the invention is as follows:

ated totalising apparatus is closed. Normally the lever 5 carrying the mercury tube Figure 3 is a part sectional plan on the line 3-3 tiltable switch l occupies the position seen in Figof Figure 2. ure 1, in which position the circuit through the According to this embodiment of the invention driving motor for the totalising apparatus of the 50 the circuit from the supply mains to the electric weighing mechanism is broken, this position being motor for driving the totalising apparatus indetermined by the contact of the upper edge of cludes a tiltable mercury switch 4 which is conthe lever 5 with the underside of the projecting nected by straps l to a lever 5 which lever norstop pin [4, and the fact that the roller ll assomally tends to move the switch 4 into the circuit ciated with the lever 5 is supported by the sharp 55 extremity of the arm I2 of the lever l2. Assuming now that a load is applied to the lever system of the weighing mechanism then the short arm of the lever I! falls and in so doing through the contact of the adjustable stop I8 and the flexible strip I9 pressure is applied to the pin I2 projecting from one arm of the lever I2, thereby turning this lever and removing the support of the arm i 2 from beneath the roller I I, thus permitting the lever 5 to fall to the position seen in Figure 2, which results in the tipping of the mercury switch 4 and the closing of the circuit through the electro-magnet 9. During this circuit-closing operation, the roller II on the lever 5 is hearing against one edge of the arm I3 of the bellcrank lever I3 with the result that when the lever 5 reaches its lowest position the pointed end of the arm I? passes over the top of the roller II and serves as a holding-down device for the lever 5 against the attractive force generated by the energisation of the electro-magnet 9, this holding-down position of the bell-crank lever I3 being determined by the position of the adjustable stop I6. The counter-weighted lever I2 is carried to the position seen in Figure 2 by the contact of the flexible strip I9 with the pin I2 and the lever is maintained in this position by the pressure exerted by the pin 5 projecting from the lever 5 upon the upper edge of the lever I2 which is limited in its downward movement by the fixed stop pin- I5.

Assuming now the load is removed from the weighing apparatus the short arm of the lever I'I moves upward and in so doing the adjustable stop Id strikes the laterally projecting pin I3 of the bell-crank lever I3 thereby releasing the arm It from its holding-down position relative to the roller I I and permitting the attractive force of the electro-magnet 9 through the armature 8 raising the lever 5 to its circuit breaking position as seen in Figure; 1. At the same time the upward movement of the short arm of the lever I'I frees the counterweighted lever I2 so as to permit this lever under t) e action of the weight I2 to swing back to the position seen in Figure 1, when the pointed end of the arm I 2 of this lever is again positioned under the roller I I to definitely support the lever 5 and thus maintain the tiltable switch 4 in the circuit-breaking position, the upward or return motion of the counterweighted lever I2 being limited by its contact with the adjustable stop I6. The mechanism is now reset for a subsequent operation.

It will be appreciated that by the employment of the counterweighted control lever I2 and the bell-crank lever I3 that the switch-carrying lever 5 is positively maintained either in its upper or in its lower position according to requirements irrespective of the normal gravitational action of the lever 5 and of the attractive force which is applied to this lever through the electro-magnet 9, so that there maybe said to be a positive holding up of the lever 5 by the lever I2 and a positive holding-down of the lever 5 by the bell-crank lever I3 independent of the force of gravity or of the return or counter-operative force which are associated with this lever through the electromagnet 9 as has been explained.

What I claim is:

1. An electric switch control means, comprising a switch of the mercury tiltable type, an overhanging lever supporting said switch, which lever normally tends, under the force of gravity, to move the switch to the circuit making position, an electro-magnetic device coupled to said lever energised upon the completion of a circuit operating to return the lever to its circuit breaking position, and a pair of locking levers one adapted to positively support the said switch carrying lever in its raised or circuit breaking position, and the other adapted to positively hold the switch carrying lever down in its circuit making position, said pair of levers co-operating with a movable element of a weighing system whereby each of the said pair of locking levers in turn is positively tripped to release the switch carryinglever.

2. An electric switch control means associated with a weighing mechanism, comprising a tiltable mercury switch, an overhanging lever on which said switch is mounted, normally operating under the force of gravity to maintain the said switch in the circuit closing position, an electromagnetic device coupled to the said lever normally tending upon the completion of the circuit through the said device to restore the lever to the circuit breaking position, a counterweighted lever adapted to co-operate with a roller mounted on the switch carrying lever to maintain the said lever in its circuit breaking position, and a bell crank lever adapted to co-operate with the said roller to maintain the switch carrying lever in the circuit making position, the said counter-weighted lever and the bell crank lever both being adapted for positive operation by means of a movable element in the weighing system for the purpose of alternatively tripping the said levers so as to free the switch carrying lever and to permit of its performing its normal operation in one direction under the force of gravity, and in a converse direction under the attractive influence of the electro-magnetic device, and stops limiting the movements of the said levers.

ARTHUR BINN S.

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