US 2356521 A
Description (OCR text may contain errors)
to the electric drill.
Patented Aug. 22, 1944 UNITED swlrc'ir STRUCTURE William B.'-Kochner, St. Louis, Mo., assignor to 'l Knapp-Monarch=`Company, St. Louis, Mo., a
corporation or'v Missouri l v Application June 1, 1942, VSerial No. 445,340
s claims. (C1. 20c- 157) My present invention relates to a switch struc-A ture particularly adaptable for electric drills and thelike and designed for being built into the handle thereof.
One object of the invention is to provide a switch structure which minimizes the use of metal by its design, being almost entirely of Bakelite or any suitable insulating material or plastic, with only the` current-carrying parts being formed of metal. Y
A further objectis to provide a switch structure which is simple from the standpoint of the number of parts involved in its construction and easy to assemble and wire into the circuit of the device to be controlled thereby.
Another object is to provide an inexpensive switch structure which has snap action to minimize arcing at the contacts, and which has a number of design features so related as to .accomplish all the necessary results involved, with a minimum of parts.
With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my device whereby the objects contemplated are at, tained, as hereinafter more fully set forth, Vpointed out in my claims and illustrated in thev accom-` panying drawing, in which:
Figure l is a side elevation of my switch struc-V ture as applied to a handle of an electric drill or the like, parts of the handle being broken away i and other parts being shown in section to .show
Where the wires may enter and leave the handle; Figure 2 is an enlarged vertical view through a portion of the handle and through my switch.
Figure 3 is an enlarged sectional View on the line 3-3 of Figure 1; Figure 4 is a sectional view on the line` 4-4 of Figure 2;
lFigure 5 is a bottom perspective view of a switch actuator of my switch structure; and
Figure 6 is a sectional view similar to Figure 2,
showing the parts in a different position.U
On the accompanying drawing I have used the reference character H to indicate generally a housing in the form of a handle for an electric drill or the like. The handle H has a, iiange I0 for attachment to the motor of the drill and -is provided. with openings I2 and III for current wires to extend respectively into the handle from arsource ofl current supply and from the handle The handle H is hollow, being formed of Bakelite or other plastic material in two halves, parted vertically at thecenter,
and the two halves, after Abeingforme'd,` are retained in assembled relati n to each other by rivets or bolts l5. f
Each half of the handle H includes a side Wall IB'and a top iiangeA Il. The flangesV Il extend toward and contact with each other at the center of the handle and are retainedv in contact by the Yrivets or bolts '|5. The' parting line is shown at I8 in Figure 3, and the flanges I'I are not sectioned in Figures 2 and 6 to thereby indicate that the section in these gures is taken at the parting line'.
A shelf velementlS extends inwardly from each side Wall I6, and'these shelf elements terminate spaced from eachother, as shown in Figures 3 and 5, the space being indicated at 2 [Lf "A pair of notches 2| is provided in each shelf element I9 to receive downwardly extending terminal ends 22 of stationary contact strips 23. The contact strips have down-turned terminal ends 2li notchedv as at 25 to receive circuit wires that are to be soldered thereto. The terminal ends 24, it will be noted, contact the ends of the shelf elements I9 whereby, in conjunction with the" terminal ends 22 being con'iined inthe notches 2|, the contact' stripsA 23 are confined against longitudinal movement relative to the shelf elements. y
The side walls I6 are thickened as shown at 26 in Figure 4, and between the thickened portions 25 a switch actuator A is mounted for sliding movement. The sides of the actuator Aare confined by the thickened portions 26', whereas the bottom of the actuatorv A slides on the shelf elementull Vand the top thereof slides beneath the surfaces 2 of thegflanges Il, `which surfaces are Aparallel to the shelf elements I9. The switch actuator'A has a thumb engageable portion 28 extending through a/slot 292'in`the handle H, such slot being formed by registering notches in the flanges Il. From -the construction ofY the parts just described it lwill beI obvious that .the actuator A is confined-to `Sliding movement along a predetermined axis, and is limited in such sliding movement by thevends' of the notches 2,9.
The switch actuator Av has a recess 30 in its bottom surface, therebyleaving end walls 3|. The end walls 3| arenoizchei as'atv32,l the notches 32 ,being narrowerA than the recess 33. The notches 32 are slightly` wider'than ther stationary contact strips 23 andI straddle -them to l:coniine them against lateral movement onjthe shelf elementsl9.. y M
In the'recess 3451A mount.'a/movablejcontact strip `V33 which is slightly less `infwidth than the width of the recess, slightly less in length than the length of the recess, and wider than the notches 32. The contact strip 33 has a pair of humps 34 to coact at times with humps 35 formed on the stationary contact strips 23. A spring 36 is positioned behind the movable contact 33 and is positioned in a socket 31 extending up into the thumb engageable portion 28 of the switch actuator. The movable contact 33 is thereby floatingly mounted in the recess 30 and biased to engage the contact strips 23.
Practical operation In the operation of my switch structure, beginning with the closed circuit position of Figure 2, it will be noted that the humps 34 of the movable contact 33 are completely seated on the humps 35 of the stationary contacts 23. Accordingly, a circuit is established across the contacts 23 by the bridging contact 33. j
When it is desirable to move the switch to off position the thumb engageable portion 28 is engaged and the switch actuator A thereby slid rearwardly. As illustrated in `Figure 6, this causes the movable contact 33 to ride up on the humps 35 of the stationary contacts23 until, finally, the right-hand end of the contact 33 leaves the hump 35 of the right-hand contact 23, thereby breaking the circuit. 'Ihe break willy be with snap -action, because of the resistance to movement being encountered by the compression of the spring in Figure 6 until the movable contact is on the tops of the humps k35, whereupon there is no further tendency to raise the movable contact against the tension of the spring. The operators thumb will accordingly move the actuator A quickly to the open circuit position because of this reduction in resistance to its movement. The open position of the switch is shownby dotted lines in Figure 2, wherein it will be noted that the central portion of the movable contact 33 is riding on top of the hump 35 of the left-hand stationary contact 23.
In closing the switch, the actuator A is moved forwardly of the handle H, causing contact to first be made between the right-hand end of contact 33 and the hump 35 of the right-hand contact 23 with a snapping of the switch to closed position after the position of Figure 6 is reached, and the spring 36 thereupon forces the humps 34 down over the humps 35.
Some changes maybe made in the construction and arrangement of the parts: of my device without departing from Ythe real spirit and purpose of my invention, and it is my intention to coverby my claims any modified forms of structure, or use of mechanical equivalents, which may be reasonably included within their scope.
I claim as my invention:
1. In a switch structure for handles and the like, said handle constituting a housing vfor the switch structure. and being for-med in two parts with a cavity between said parts, said handle parts having shelf elements projecting toward each other, a pair of stationary contacts on said shelf elements, a switch actuator slidable on said shelfv elements and confined between the shelf elements and the handle when the two parts of the handle are held assembled together, f said switch actuator having a recess, and a movable contact mounted therein and adapted in one position of the switch actuator to bridge both of said stationary contacts 2. In a switch structure for electric drills and the like, a handle for the drill formed in two parts with a cavity between said parts constituting a housing for the switch mechanism, said handle parts having shelf elements projecting toward each other, a pair of elongated stationary contacts on said shelf elements and having parts coacting therewith to prevent movement of said stationary contacts on said shelf elements, a switch actuator slidable on said shelf elements and being confined between the shelf elements and the handle, said switch actuator having guide notches straddling said stationary contacts to be guided thereby and having a recess, and a movable contact floatingly mounted therein and adapted in one position of the switch actuator to bridge said stationary contacts.
3. In a switch structure, a hollow handle formed in two parts and constituting a, housing for the switch mechanism, said handle parts having shelf elements projecting toward each other, each of said shelf elements having a pair of notches, a pair of stationary contacts on said shelf elements having portions received in said notches when said two handle parts are assembled together, a switch actuator slidable between said shelf elements and a wall of the handle, said switch actuator having a, recess, a oating contact mounted therein and adapted in one position of the switch actuator to bridge both of said stationary contacts and in the opposite position of the switch actuator to break contact between them, and a, spring biasing said oating contact toward said shelf elements and said switch actuator toward said wall of the handle.
4. A switch structure for electric drill'handles and the like formed in two parts with a cavity between said parts constituting a housing for the switch mechanism, said handle parts having shelf elements provided with registered notches, a pair of elongated stationary contacts on said shelf elements and each having parts received in said notches of said shelf elements to preventlateral movement of the stationary contacts thereon, a switch actuator slidable on said shelf elements and confined between the shelf elements and said handle, said switch actuator having a recess and having guide notches straddling said stationary contacts and thereby guided for slidingmovement, a movable contact in said recess for bridging coaction with said stationary contacts, said guide notches being narrower than said recess to prevent longitudinal movement of said movable contact within said recess relative to said switch actuator with the ends of said recess oonning the ends of said movablecontact, said switch actuator having a thumb engageable portion and said handle having a slot through which said thumb engageable portion extends tothe exterior of the handle.
5. In a switch structure, a housing, said housing being formed in two parts with a shelf element projecting from each part and having registered notches, a pair of stationary contacts on said shelf Velements having terminarendsreceived in said notches, a switch actuator slidable between said shelf elements and a wallyof said housing, said switch actuator having ,arecess therein, a movable contact carried insai'd recess for bridging coaction with said stationary con-J` tacts, said switch actuator having arthumb engageable portion and said wall Vof the" housing having a slot through which said thumb engageable portion extends to theY exterior ofthe hous- 6. A-'switch structurercomprising a two-part:
housing having shelf elements projecting toward each other and provided with registering notches, a, pair of stationary contacts each comprising a longitudinal body portion, a hump adjacent one end thereof and terminal ends bent downwardly therefrom, some of said terminal ends being received in said notches and others engaging the ends of said shelf elements to coniine said stationary contacts against longitudinal movement on said shelf elements, a switch actuator slidable between said shelf elements and a wall of said housing, said switch actuator having guide notches coacting with said stationary contacts to retain them in proper alignment and having an enlarged recess between said notches, a movable contact in said recess and having a pair of humped portions to coact with the humped portions of said stationary contacts in the closed position of the switch, a spring in said recess behind said movable contact, said movable contact and said recess being wider than said notches to confine said movable contact against endwise movement relative to said switch actuator.
'7. In a switch structure, a support, a pair of stationary contacts thereon, a switch actuator slidable on said support and having a recess therein adjacent said stationary contacts, a floating movable contact confined in said recess against lateral movement relative to said switch actuator, said stationary7 contacts and said movable contacts having coacting humps and depressions respectively, a spring in said recess and bearing against a portion of said movable contact intermediate said depressions and thereby tending to engage said movable contact with said stationary contacts, and means for confining said switch actuator to movement through a limited space, one limit of the movement permitting said depressions of said movable contact to engage said humps of said stationary contacts and the other limit of movement permitting said movable contact to ride with said portion thereof supported on the hump of only one of said stationary contacts and with the backs of said depressions closely adjacent the bottom of said recess to thereby hold said movable contact against tilting.
8. A switch structure comprising a hollow handle being formed in two parts with a cavity between ksaid parts constituting a housing for the switch mechanism, said handle parts having shelf elements projecting toward each other, a pair of elongated stationary contacts on said shelf elements and each having a hump and a terminal end substantially normal to the plane of the stationary contacts, said shelf elements having notches registering with each other and receiving said terminal ends when said two handle parts are assembled, a switch actuator slidable on said shelf elements and confined between the shelf elements and a wall of said handle, a movable contact carried by said switch actuator and having depressions to receive said humps when said movable contact bridges said stationary contacts, said movable contact in off position of the actuator being supported on only one of said humps, said actuator having a thumb engageable portion and said wall of each part of said handle having a second notch, said second notches'registering to form a slot when said two parts are assembled through which said thumb engageable portion slidably extends to the exterior of the handle.
WILLIAM B. KOCHNER.