US1566155A - Motor-starting switch - Google Patents

Description

Dec. 15, 1925 1,556,155

R. K. MASON MOTOR STARTING SWITCH Filed June 23, 1920 4 Sheets-Sheet l Dec. 15, 1925 1,566,155

R. K. MASON MOTOR STARTING swITcH Filed June 23, 1920 4 sheets-sheet 2 M? 55, @vaww SM Y@ @Wow m 0 Dec. l5, 1925 R. K. MASON MOTOR STARTING swI'rcHy Filed June 23. 1920 4 Sheets-Sheet 5 IE- E nl "In".

El E- 3mm/woz' My@ @Vxwow R. K. MASON MOTOR STARTING SWITCH' Dec. 15 ,Y 1925 I 1,566,155

Filed June 23, 1920 4 Sheets-Sheet 4 :I rE-- J l :Fri- I E l Vw E i (D O 31m/vento: rcfy @Kga/.mw

Patented Dec. 15, 1925.

UNITED STATES N 1,566,155 PATENT OFFICE.

RALPH X. MASON, 0F BANTAM, CONNECTICUT, ASSIGNOIR OF ONE-HALF TO JOHN H. LANCASTER, 0F LITCHFIELD, CONNECTICUT.

MOTOR-STARTING SWITCH.

Application lued June 23, 1920. Serial No. 391,032.

T o all whom it may concern.'

y tains to make and use the same.

My invention relates to improvements in electric switches, more particularly ,motor starting switches.

I am aware that motor starting switches having contacts bridged by non-fusible means for starting and by fusible means :tor running have heretofore been devised to prevent blowing of fuses when starting the motor, but one of the principal objects of my invention is to provide a novel form of switch which will be truly a safety switch, all parts being housed within a casing when the switch is closed, the cover of said casing being then locked, but released automatically when the switch is opened. Installation of new fuses or other automatic cutouts which may be used, is thus permitted only when such fuses or devices are entirely dead.

In carrying out the above end, the switch operating handle is movable to two positions, one to set the switch for starting and the other for running, and a further object is to provide locking means for the casing cover which will be applied when. the handle is moved to either of said positions and will be released only when said handle is moved entirely to switch opening position.

Another object is to provide stop means for arresting the movement of the handle when moved to starting position, and to provide spring means exerting its tension to return said handle to switch opening position until it has been moved beyond said starting position, said spring means then acting to rapidly complete the closing ot the switch. B v this arrangement, it is impossible for theI operator to inadvertently run the motor continually 'with the switch at starting position and the fuses or the like out ot circuit.

Yet another object is to so arrange the above mentioned spring means as to cause xthe same to rapidly complete the opening movement of the switch after such movement has been partly effected by hand.

A still further object is to provide a motor starting switch in which both the line and load ends of the circuit are entirely disconnected from both fusible and nonfusible switch means when the switch is opened, thus insuring that disabled fuses or other cut-outs may be renewed or otherwise placed in operative condition without dan- Other objects are to yieldably mount both the contact bridging means'used for starting and that employed for running, thereb allowing proper engagement thereof wit the line and load contacts; to incorporate a resistance in the starting bridge and thus limit the current supply which is greatly above normal when starting; and 'to make provision for engaging the running bridge with the contacts before the starting bridge is entirely disengaged therefrom, thereby causing no lull in the supply of current to the motor while shifting the switch from start-ing to running position. Blowing of fuses is not therefore apt to occur as in other forms of starting switches in Ywhich the current supply is interrupted while moving the switch from starting to running position.

With the foregoing and minor objects in view, the invention resides in the novel construction and combination of parts hereinafter described and claimed, the descriptive matter being supplemented by the accompanying drawings which form a part of this application.

Figure 1 is a side elevation with parts broken away and in section showing the open position of the switch,

Fig. 2 is a view similar to Fig. 1 illustrating` the parts in starting position,

Fig. 3 is a vertical section of the 'switch .in running position,

Fig. 4 is a vertical section on the plane indicated by line 4-4 of Fig. 1.

Figs. 5 and 6 are detail views similar to a portion of Fig. 4 showing different positions of parts,

Fig. 7 is a detail vertical section showing the manner in which both the motor starting and the motor running contact-bridging means coact with the fixed contacts while moving the switch. from starting to running position,

Fig. 8 is a detail vertical section partly in elevation, showing the manner of yieldably mounting both contact bridging means for accurate engagement with the fixed contacts, U

Figs. 9 and 10 are detail sectional views on lines 9 9 and 10-10 of Fig. 8,

Fig. 11 is a view similar to Fig. 8, showing a different form of construction,

Fig. 12 is a horizontal sectional viewon is hereshown operating over a false front 3 provided with an opening 4. The sections of the casing may well be connected by the means and for the purpose set forth in my.

U. S. application Serial No. 386,126, Filed June 2, 1920. Vithin the casing, spaced contacts 5 are mounted in any preferred manner, and with these contacts, both motor starting bridging means and motor running bridging means coact, all of said bridging means being carried by a movablebase 8 which is disposed within the casing 1. The base is so mounted as to be positioned at and close the opening 4 when the switch is in off positiQn, the fuses 9 or other automatic cut-outs of the motor running bridging means being then accessible for renew ing or otherwise placing in operative coildition. Due to the arrangement yet to be described, the cover 2 is locked against opening until the base 8 is moved to switch opening position as seen in Fig. 1, butl when in this position, the locking means is released so that the cover may be opened. When this takes place, the fuses and their holding clips or other equivalent parts are entirely dead since' the switch is of a double.

break nature, and access to any live parts within the casing is then prevented by the fact that the false front 3 and the4 base 8 form a complete barrier.

The base 8 might well be mounted and operated in numerous ways, but I prefer to use an arrangement similar to that of my pending U. S. Patent No. 1,424,578, of August 1, 1922. A pair of parallel crank arms 10 are pivoted at 11 to one end of said base while links 12 are pivotally connected at 13 with the other end thereof, the ends of said links remote from the pivots 13 being suitably pivoted to the sides of the casing as indicated at 14. The crank arms 10 are rigidly carried by a rock-shaft 15 which extends across the casing 1, and suitable spring means such as the coil 16 acts on said shaft for purposes to be set forth, said shaft being shown as provided with' a crank 17 to which the spring 16 is connected. This sprinU serves first to hold the switch yieldingly in open position. second to open the switch automatically au attempt is made to leave the same in start ing position, third to rapidly complete the closing of the switch when the handle 1s moved beyond starting position, and fourth to rapidly com/plete the opening of the switch when it has been started toward the opening position by hand. During the action'of the spring, it is desirable that some lost motion shall be provided between the shaft 15 and the handle 18 which is used for operating said shaft. To obtain this result, any adequate means may be used but at least one end of the sl' .ift is preferably squared and is received loosely in an opening 19 in one end of the handle, said opening however having a plurality of inwardly eX- tending lugs 2O .adapted to strike the flat sides of the shaft and thus form a driving connection between said shaft and handle. W'hen the spring 16 takes up the movement of the shaft, the flat sides of the latter merely move away from the lugs 20 and it will thus be seen that said spring will not suddenly jerk the handle from one position to another. Furthermore, control of the switch is taken out of the hands of the operator, insuring quick make and quick break.

As above stated, the operating handle 18 must move to one position for starting and to another to set the switch for continual operation, and although other means can be used to arrest the movement, of said handle when moved to starting position, I have shown relatively fixed and movable stops 21 and 22 carried respectively by the casing and the handle. vA coil spring 23 or other suitable means normally holds the movable stop 22 in position to strike the fixed stop 21 when the handle 18 is moved toy close the switch, thereby arresting the movement of said handle when the switch is in starting position as seen clearly in Fig. 2. By means of a thumb operated rod 24 or any other preferred means, the stop 22 may be moved to a position in which it will clear the fixed stop 21, thus permitting the handle tobe moved to its second position to` leased however and the handle 18 moved beyond starting position, the crank 17 passes dead center and the spring 16 then acts onv said crank to rapidly move the base 8 to run- It is thus insured thaty ning position. vA quick-make switch is thus provided which insures against arcing.

The motor starting contact bridging means and the motor running bridging means are both yieldably mounted on the base 8 to permit accurate engagement thereof with the contacts 5 and common means are preferably used in so mounting said bridging means. The motor running bridging means comprises contacts or blades movable with the base 8 for engagement with the contacts 5, and although any automatic circuit interrupting means may be used to connect said contacts electrically, I have shown the fuses 9 engaged with clips 26 on the outer ends of the blades 25. These blades and clips are yieldably mounted on the base 8, preferably by passing the former loosely through openings 25a in the base 8 and holding them therein by springs 25b (see more particularly Figs. 8 and 11). By this arrangement the blades 25 may shift iaterally to properly engage the contacts 5, regardless of any inaccuracies in construc- ILion or lateral movement of the base 8 from wear. No claim is herein made for the arrangement in question, aside from its association with the motor starting bridging means, in view of Patent 1,424,578 above referred to.

`The motor starting contact bridging means is adapted to bridge the contacts 5 prior to bridging thereof by the means 25-26-9 and said motor starting bridging means is preferably carried by insultaing plates 27 secured to the blades 25 (see more particularly Figs. 8, 9 and 10 for details). The bridging means in question may comprise two contact plates 28 and a resistance 28 as seen in Figs. 1 to 10, or may consist merely of a single bar 29 as shown in Figs. 11 and 12. In either instance, the yieldable mounting means of the blades 25 will serve also to allow self adjustment of the motor starting bridging means as well as said blades, to accurately enga-ge the contacts 5. These contacts preferably have their ends bent inwardly into parallel relation to provide' contact surfaces 5 and in the form of construction so far described, these surfaces are longer than the spaces between the blades 25 and the bridge 29 or 28--28a (see Figs. 5, 6 and 7). It is thus insured that the blades 25 shall partly engage the contacts 5 before the bridge 29 or 28-28a leaves the same (see Fig. 7). By this relation, there is no lull in the passage of currentto the motor or other load, while shifting the switch from starting to ruiming position and consequently blowing of fuses or the like is not apt to occur, as when the current is momentarily cut off while shifting most forms of starting switches from starting to running position.

When starting, the current is greatly above normal and to prevent any possible in jury to the motor, the resistance 28u is useful, since it limits the current supply. However, a resistance need not be in all cases used, and if desired the bridge 29 might be of resistance material. This however is not a preferred-construction in view of the heat generated which would have a tendency to fuse the bridge to the contacts 5.

The motor starting contact bridging means so far described is for use when the contacts at the saine side of the switch are to be bridged but when the well known Star- Delta system is used, short starting bars 30 are employed, electrically connected by a suitable conductor 30, as in Figs. 13 and 14. The bars 30 may well be mounted on a rib 30 formed on the base 8, but they may be yieldably mounted 'upon the blades 25 if desil-ed, in much the same manner as the construction above described.

lVhen the bridge 28--28a or 29 is used and is engaged with the contacts 5 for starting, the current takes the same course through the wiring not shown) as when the blades 25 are engaged with said contacts. When the bars 30 are employed however and the switch is in starting position as seen by the upper dotted outline of Fig. 13, the course of the currents is entirely dierent as in the ordinary Star-Delta system. When the bars 3() are disengaged from the contacts 5 after starting, the blades 25 follow them into engagement with said contacts, but in this form of switch, contrary to that previously described, the bars 30 entirely leave the contact surfaces 5a before the blades 25-engage them.

Any preferred locking means might be employed for the cover 2, but I preferably use that shown in Patent No. 1,424,578 above referred to, including a link 32 pivoted to said cover at 33, said link having` a longitudinal slot 34 enlarged at one end as seen at 35. The enlargement 35 is adapted to receive a rotary locking member 36 carried by one of `the links 12 to lock the cover against opening when the switch is in the starting position shown in Fig. 2 or in the running position of Fig. 3. The member 36 is operative the moment the barrier or base 8 is moved toward switch closing position and thus when the switch is set for either running or starting, it is impossible to gain access to the interior of the casing 1 and consequently injury to the operator is prevented. When the switch is completely opened, the locking device 36 is aligned with theslot 34 as seen in Fig. 1, thereby allowing the cover 2 to open, but all parts are then entirely dead and no injury can result.

The operation of the switch will probably be obvious from the foregoing but may be briefly described: With the switch entirely opened, all parts stand as in Figure 1, in

which positionthe cover 2 may be opened for re-fusing the switch or adjusting any automatic cut-outs which may be used in place of fuses. When the handle 18 is moved until the stops 22 and 21 abut, the motor starting bridge 28-28a or 29, or the bars 30 as the case may be, are engaged with the contacts 5 for starting the motor without having any fusible means or the like in the circuit. (See for instance Fig. 2). When this position of parts is reached, the spring 16 is under tension to return the switch' to open position if the handle 18 is released, and thus the motor cannot be operated for any considerable length of time with the switch in starting position. By releasing the stop 22, the handle 18 may be moved toward its second position and the moment the crank 17 passes dead center, the spring 16 comes into play to rapidlycomplete the closing of the switch. The motor starting bridging means is thus quickly disengaged' from the contacts 5 and the switch blades 25 follow them into full engagement with said contacts under spring' action. The switch is now in running position with the fuses or the like 9 in circuit to take care of any overload. Reverse movement of the handle 18 starts the switch toward open position and this movement is rapidly completed by the spring 16. The stop 2l. may be cam-shaped on its lower side as indicated so that the stop 22 will be moved against the tension of its spring 28 during movcment of the handle to switch opening position.

I attach great importance to the following: The switch is of double break nature and both the line and load contacts are cntirely disconnected from the fusible or other motor running switch means when the switch is opened. This double break feature is not only of advantage in preventing injury when. renewing fuses or performing like work, but the line may be connected to either end of the switch and the load to the other. With the common forms of motor starting switches there is even more danger than with regular line switches, of connecting the line to the wrong end of the switch. Other features of advantage are the mounting of both the motor starting and running contact bridging means on a single base, always insulated from each other except while moving one form of the switch from starting to running position; and the provision of spring means of some sort acting on the switch operating means for normally holding the switch open, for resisting the closing of the switch until it is moved past starting position, for then rapidly completing the closing movement, and for exerting its tension to quickly open the switch. A.,

still further advantageous'feature is that access to live parts is positively prevented when the switch is in either starting or running position, making it impossible to 0btain injury therefrom. The only time at which the moving switch parts are accessible is when the switch is opened, and due to the double break nature of the device, all of such moving parts are then entirely dead. The yieldable mounting of the two contact bridging means, the provision of the resistance 28, and the proportion of parts for engaging the blades 25 with the contacts 5, before the latter are totally disengaged by the other bridging means (2S- 28a or 29), are also highly important features.

The structure disclosed produces the results required in an effective manner, but the claimed invention may assume forms other than those shown.

I claim:

l. In a double break motor starting switch, paired contacts ixedly mounted, a carrier mounted for movement bodily toward said contacts, and a pair of spaced fusibly connected switch blades extending in the same direction from said carrier and adapted to engage said fixed contacts for running; together with a non-fusible bridge spaced throughout its length from both switch blades and adapted toI engage said contacts for motor starting, insulation connecting said non-fusible bridge with both of said switch blades and co-operating with the latter in forming the sole supporting means for'said bridge, and means for moving said carrier in the same direction to two distinct positions to move said non-fusible bridge into engagement with said paired contacts and to then present said switch blades to said contacts. f

2. An encased double break motor starting switch having line and load contacts and a door giving access to the interior of the casing, a movable base in the casing forming therewith a barrier to live switch parts when the switch is off and the door open, and switch blades extending rearwardly from and carried by said base for engaging said line and load contacts; to-

ether with a motor starting bridge located 1n rear of said switch blades, insulation extending rearwardly from said blades, said insulation carrying said motor starting bridge and :insulating all parts thereof from said blades, and means including a handle o-n the exteriorof the easing for moving said blades in the same direction to two distinct positions to first engage said starting bridge with said contacts and to then present said blades to said contacts.

3. In a double break safety motor starting switch, an enclosing casing having a doo-r, line and load contacts within the casing,

motor starting and'motor running contact' bridging means 1n sald casing, a movable Meanies base in the casing carrying both of said bridging means and forming withthe switch casing a positive barrier preventing access through the door to both line and load contacts when the switch is open, means for operating said base to engage said motor starting and running bridging means with said contacts and entirely free them from said contacts when the switch is open, and switch controlled locking means for said door effective when either bridging means is in engagement with said contacts and also effective while shifting the switch from Starting to running position.

4. A starting switch comprising a casing, contacts therein, a movable base in said casing, links Aconnecting one end of said basel with said casing, a cranked rock shaft extending across said casing, and having crank arms pivoted to the other end of said base, a handle on the exterior of said casing connected to said rock shaft, motorv starting and running contact bridging means carried by said base, a fixed stop on the casing and a movable stop on said handle for arresting the movement of the switch means when said motor starting bridging means is in operation, and spring means acting on the cranked portion of said rock shaft for quickly completing opening or closing movement of the switch, said spring means exerting a switchopening tension on said rock shaft until said handle is moved beyond said fixed stop.

5. A switch comprising fixed contacts, a movable switch member coacting with said contacts, means for operating said switch member, including a rock shaft and a handle therefor, said shaft having a flat sided end and said handle having an opening into which said end projects loosely, said handle being also provided with lugs extending inwardly from the wall of said opening for contact with the fiat sides of said shaft after limited lost motionof said handle and shaft, and spring means acting on saidshaft for rapidly completing the movement thereof after starting of suoli movement by said handle.

In testimony whereof if have hereunto set my hand.

RALPH K. MASON.

Images