US3511951A - Hand-held switching device with interlocked trigger actuating means - Google Patents

Description

HAND-HELD SWITCHING DEVICE WITH INTERLOCKED TRIGGER .AC'I'UATING MEANS y 12, 19-70 R; G. MILLER 3,511,951

Filed Feb. 12, 1968 2 Sheets-Shet 1 Eire-.3.

INVENTOR. 1905627 6-. M/LLEQ Y FOWL 2, KNOBBE 5' M4? TEA/5 May 12, 1970 v R. G. MILLER HAND-HELD SWITCHINGD EVICE WITH INTERLOCKED TRIGGER 'ACTUA'IING MEANS Filed Feb. 12, 1968 2 Sheets-Sheet 2 w 0 M mw G 15 7 ET 2 5e 5 2 w WM 0 P W 2 5a 9. Ma 10.

3,511,951 HAND-HELD SWITCHING DEVICE WITH INTER- LOCKED TRIGGER ACTUATING MEANS Robert G. Miller, Santa Ana, Calif. (7455 Bannock Trail, Yucca Valley, Calif. 92284) Filed Feb. 12, 1968, Ser. No. 704,660 Int. Cl. H01h 9/06, 9/24, 21/10 US. Cl. 200-157 ABSTRACT OF THE DISCLOSURE Two triggers are pivotally mounted along one edge of an elongated molded housing with their free ends extending toward each other and movable to operate a pair of switches confined by internal walls within the housing. In one embodiment, one trigger can be depressed independently of the other trigger to actuate a switch, but when the second trigger is depressed to operate a second switch, the free end of the uecond trigger engages the first trigger so that both switches are operated. In another arrangement using the same housing and switches, the free ends of the triggers move in overlapping paths so that either can be operated independently of the other but they cannot be operated simultaneously. In a third arrangement, a rocker element cooperates with the free ends of the triggers to prevent both triggers from being simultaneously operated.

8 Claims This invention relates to hand-held switching devices in which triggers for two switches operate in an inter-related manner. The invention further relates to an improved approach for assemblying a hand-held switching device. The devices are particularly useful in connection with controlling X-ray equipment or for controlling oppositely directed motion, such as up and down motion for an electric crane.

With X-ray apparatus including an X-ray tube having a rotating anode, it is essential that the anode be rotating when an exposure is made in order to avoid damage to the tube. Such apparatus normally includes a protective circuit which theoretically makes it impossible to make an exposure unless the anode is rotating; but since there is a possibility that such a circuit might fail, it is desirable that the switch device controlling the apparatus include means for providing additional protection to prevent such incorrect operation.

Such a control is not only important from the standpoint of protecting the expensive X-ray apparatus, but more importantly the patient should not be exposed to any unnecessary X-rays. To obtain a good diagnostic radiograph, the patient must be completely immobilized. This will enhance the detail and eliminate blurring. It is therefore important for an X-ray technician to make the exposure at the precise moment the patient is absolutely still. This is especially a problem with patients such as infants who are diificult to keep motionless. The need to repeat exposures also naturally wastes X-ray film and wastes the time of the machine, the operator and the patient.

A control of this nature may also be useful in other electrical circuits wherein sequence safety is desired. While hand-held switching devices directed to this general situation are known, they have not been completely satisfactory from a standpoint of convenience and reliability.

In the operation of certain electrical apparatus such as electrical overhead cranes, motor means are provided for up and down motion. It is desirable that two switches for controlling the motor means be positioned within a single hand-held switching device so that the operator has one L mited States Patent hand free to position equipment being moved by the crane. To protect the equipment, it is desirable that the switching device be arranged so that only one switch at a time can be actuated.

In many operations, hand-held switching devices are subjected to considerable abuse such as being dropped or banged against heavy objects. Hence, it is very important that the device be ruggedly constructed to withstand such treatment without frequent repair. Further, it is important that such a device be constructed so that it can be easily and quickly assembled and disassembled, thereby permitting easy replacement of switches and repair of other components if necessary. It should be kept in mind that the equipment controlled by switching devices is often very expensive and in continual use by well paid personnel. X-ray equipment is a good example of this. Thus, delays due to inoperative switching devices are very costly. To be competitive, it is of course also necessary that a switching device be low in manufacturing cost.

SUMMARY OF THE INVENTION In accordance with this invention, a pair of micro switches are supported within a housing adapted to be held in one hand. A first finger-operated trigger extends along one side of the housing and is supported by the housing in a manner such that one end of the trigger is movable to operate one of the switches. A second trigger extending along the same side of the housing is supported by the housing in a manner such that one end is movable to operate the second switch and is positioned adjacent to the movable end of the first trigger. The triggers are mounted so that in one manner of operation at least one of the trigger ends causes interference with the movement of the other trigger; and in another manner of operation, at least one of the triggers may be moved to operate its switch independently of the other trigger.

In one embodiment of the invention, the first trigger, which is operated by the last three fingers of one hand, has a portion which extends into the path of the second trigger, and the second trigger which is operated by the forefinger, has a portion which engages the first trigger as the second trigger is moved to operate its switch. Consequently, the first switch is operated each time the second trigger is moved to operate the second switch. When utilized to control X-ray equipment, the first switch is connected to control the rotating anode of the X-ray tube and other circuits while the other trigger controls the exposure circuit. The operator is supposed to depress the first trigger to energize the anode rotating means and then subsequently depress the second trigger to make the exposure when the patient is still. However, if the operator should make a mistake and depress the exposure trigger first, the anode trigger is nevertheless simultaneously depressed to actuate the switch controlling the anode rotor.

In accordance with a second embodiment of the invention, the ends of the two triggers are formed and situated so that either trigger can be operated independently of the other to actuate its switch; but if both triggers are simultaneously operated, they interfere so that neither switch is actuated. The interference is caused by the fact that the free ends of the triggers move in overlapping areas and engage each other if both are moved at the same time.

In a third embodiment of the invention, the trigger ends cooperate with a rocker element which prevents both triggers from being simultaneously depressed sufficiently to operate both switches.

The triggers of the three embodiments all fit within the same housing construction and cooperate with the same switches mounted within the housing. The housing is preferably molded of plastic in two sections held together by suitable fasteners. Inner walls within the .for soldering or other mechanical connection. A strain relief arrangement for the electrical cord is also clamped within the housing without fastening elements. Thus, the entire construction permits easy repair or replacement of parts.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the hand-held switching device of one embodiment of the invention;

FIG. 2 is an exploded perspective view of the switch of FIG. 1 showing the internal structure;

FIG. 3 is a side cross-sectional view of the device of FIG. 1 with the switch triggers undepressed;

FIG. 4 is a view similar to FIG. 3 but with one of the triggers depressed;

FIG. 5 is similar to FIGS. 3 and 4 but with both triggers depressed;

FIG. 6 is a cross-sectional view of a second embodiment of the invention with the two triggers shown undepressed; and,

FIG. 7 is a view of a portion of the structure of FIG. 6 but with one of the triggers depressed;

FIG. 8 is a cross-sectional view of a third embodiment of the invention with the two triggers shown undepressed;

FIG. 9 is a partial view of the trigger ends of the embodiment of FIG. 8 with one trigger depressed;

FIG. 10 is view similar to that of FIG. 9 with the other trigger depressed; and

FIG. 11 is an enlarged perspective view of the rocker element of FIGS. 8-10.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment of FIGS. l-S

As seen in FIGS. 1 and 2, the hand-held switching device of the invention includes an elongated housing 10 which is formed to conveniently fit within one hand of an operator. The housing 10 includes a main section 11 having a large fiat end or bottom wall 12 formed unitary with a plurality of edge walls 13. A cover section 14 is joined to the edge walls 13 by suitable threaded fasteners 15.

The housing 10 is preferably molded of a strong, rugged plastic or other suitable insulating material. Molded into the main housing section 11 are a plurality of inner walls defining various cavities and recesses for confining components of the switching device without fasteners other than the screws 15. A generally circular recess 16 is formed in the upper end of the housing section 11, and a similar recess 18 is formed in the lower end of the housing. These recesses 16 and 18 open on one side leading into an elongated opening 20 in the front edge wall 13a. The recesses 16 and 18 are also open at their ends remote from the end wall 12.

Turning now to FIG. 3 as well as FIGS. 1 and 2, it may be seen that upper andtlower elongated triggers or levers 24 and 26 are located in the opening 20 in the front edge 13a of the housing section 11. A portion of each trigger extends slightly beyond the front edge of the housing so that the triggers may be easily gripped by the fingers of the operators hand. More specifically, the upper trigger 24 is positioned to be gripped easily by the forefinger of one hand on the contoured portion 25, while the lower trigger 26 is positioned to be gripped easily by the other three fingers of the same hand on the contoured portion 27.

The upper trigger 24 has an enlarged upper lobe 24a formed with a shape which is generally circular for more than 270. This generally circular upper lobe 24a is confined for limited pivotal movement within the mating recess 16 formed in the housing section 11. The lower free end 24b of the upper trigger 24 is joined by a connecting neck portion 24c to the upper lobe 24a. The inner walls of the section 11 housing form a suitable space 28 for receiving the neck portion 240 and for permitting limited pivotal movement of the trigger free end 2411 about the lobe 24a.

The lower trigger is formed with a similar enlarged lobe 26a on its lower end having a shape which is generally circular for more than 270 and is confined within a mating recess 18 formed in the lower end of the housing section 12. The upper free end 26b of the lower trigger 26 is joined to the lobe 26a by a connecting neck portion 26c, which moves within a space 29 formed by the inner walls in the housing section 11 as the free end 26b is pivoted about the lobe 26a.

Referring to FIG. 2, the inner walls of the housing section 11 define a switch receiving cavity 30 near the upper recess 16. End wall 12 forms an end of the cavity 30, and the end remote from wall 12 is open until closed by the cover section 14. The cavity 30 has a generally rectangular cross section, and the side nearest the front edge 13a of the housing opens into the elongated front edge opening 20.

Lea-ding outwardly from the recess 30 are a pair of narrow slots 31 and 32 defined by the housing inner walls formed unitary with the end wall 12. The slot 31 further joins an elongated narrow channel 33 which curves around behind the recess 30 and into a cord terminating compartment 34 formed in the lower rear end of the housing section 11. Similarly, the slot 32 joins an elongated narrow channel 35 which also opens into the compartment 34.

A second switch receiving cavity 36 is defined by the housing inner walls below the cavity 30, separated by a partition 11a. Again the end wall 12 of the housing section 11 forms an end of the cavity, while the other end is open, until closed by the cover section 14. The cavity 36 has generally a rectangular cross section and the side of the recess nearest the front edge 13a of the housing opens into the elongated front edge opening 20.

A narrow slot 37 opens from the back of the cavity 36 into the channel 35 which leads to the cord compartment 34. Another narrow slot 38 opens from the end of the cavity 36 directly into the compartment 34.

A pair of conventional, self-contained micro switches 39 and 40' are mounted respectively in the cavities 30 and 36. The switch 39 is provided with a terminal 41 which extends into the slot 31, and with a terminal 42 which extends into the slot 32. The outer end of the terminal 42 is bent to extend into the channel 35. Similarly, the switch 40 has a terminal 43 which is bent at its outer end so that the terminal extends into the slot 37 and the channel 35. A straight terminal 44 on the lower end of the switch 40 extends into the slot 38. Note that the switches 39' and 40 with their terminals are trans versely confined within their respective housing recesses 30 and 36, and terminal slots 31 and 32, and 37 and 38.

A power cord 45 for connection to the switch terminals enters through an aperture 46 in the lower edge wall 13b of the housing section 11 into the compartment 34. The cord 45 includes three insulated conductor Wires, two of which 46 and 47 are connected to separate circuits, while the third 48 is common to both circuits. The wires are encased in a suitable insulation sheath 49.

The wire 46 extends from the compartment 34 through the channel 33 and terminates connected to a U-shaped conductive element 50 positioned snugly within the slot 31. The element 50 is positioned in the slot before the switch 39 is installed so that its terminal 41 is frictionally wedged into the slot 31 between the legs of the element 50 in good electrical contact with the terminal 41, without any soldering or additional mechanical connection.

The conductor 47 is connected to a U-shape conductive element 51 which is similarly snugly positioned within the slot 3 8. When the switch 40 is installed within its cavity 36, the straight terminal 44 is frictionally received within the U-shape conductive element 51 so that good electrical contact is made without soldering or any additional mechanical connection.

The common conductor 48 is connected to an elongated conductive strip or bus bar 52 which extends into the elongated channel 35. The conductive strip 52 terminates with a U-shape conductive element 52a positioned adjacent the narrow slot 32. Hench, when the switch 39 is positioned within its recess 30, the outer end of its bent terminal 42 is frictionally received between the legs of the U-shape conductive element 52a so that good electrical contact is attained. Near the lower end of the conductive strip 52 there is formed another U-shape conductive element 52b which is located adjacent the narrow slot 37. Thus, when the switch 40 is positioned and confined within the recess 36, the outer end of its bent terminal 43 is frictionally received within the U-shape conductive element 52b.

Within the compartment 34 there is provided a strain relief means 60 for gripping the cord 45 in a manner such that the connections between the switch terminals and the conductor wires are not disturbed if someone applies a force to the cord by pulling on the housing 10, as may frequently occur during utilization of the device. The strain relief means 60 includes a pair of mating gripping elements 62, which as seen in FIG. 2 have their inner surfaces curved to mate with the cord 45. The outer lower side surfaces 62a of each of the gripping elements 62 taper or converge downwardly to mate with similar converging walls 11b forming the lower side walls of the compartment 34. The spacing between the tapered walls 11b is such that as the gripping elements 62 are forced downwardly with the tapered surfaces 62a in engagement with the walls 11b, the gripping elements 62 are forced into engagement with the insulation sheath 49 of the cord 45 so that they firmly grip the cord.

To retain the gripping elements 62 in their gripping position, a retaining element 64 is provided having a generally fiat configuration which conforms to the shape of the upper portion of the compartment 34 above the elements 62. The lower end of the retaining element 64 is bifurcated into two tongues 64a which engage the gripping elements 62, while the space 65 between the tongues 64a receives the end of the cord sheath 49. The length of the retaining element 64 between the elements 62 and the compartment end wall 11c is such that the gripping elements 62 are positively retained in their gripping position without any additional fastening means.

With the cover 14 closing the lower housing section 11, the triggers, the switches and the cord are confined within the housing. Since none of these internal components are mechanically secured to the housing, replacement of components is a brief simple operation.

Each switch 39 and 40 is provided with a springloaded actuating button 53 and 54, respectively, which extends outwardly toward the front opening 20 of the housing to be operated by the triggers 24 and 26. More specifically, the upper switch 39 is formed with a button 53 near its lower end which engages the inner side surface 24d of the free end 24b of the upper trigger 24. The switch button 53 urges the lower end of the upper trigger outwardly to its normally open or undepressed position. This outer movement is limited by the interengagement oft'he trigger neck portion 240 with the inner housing wall 11d defining one wall of the space 28, as

seen from FIGS. 2 and 3.

It should of course be understood the switches have internal contacts (not shown) controlled by the buttons 53 and 54, and connected to the terminals. In the manner described herein, the switch contacts are normally open.

The inner upper surface 26d of the free end 26b of the lower trigger 26 engages the button 54 on the lower switch 40, as can be seen from FIG. 3. The button 54 of the lower switch 40 urges the free end 26b of the lower trigger 26 outwardly into its normally open undepressed position. This outer movement of the free trigger end 26b is limited by the inter-engagement of the surface 26:: of the lower trigger with the wall He on the lower end of the housing section 11.

As can be seen from FIGS. 2 and 3, the outer faces 24 and 26 of the free ends of the triggers are arranged in generally opposing relation. The free end of the upper trigger 24 is formed with a depending projection 24g on its outer edge which mates with the surface 26f of the lower trigger 26 adjacent its outer edge. However, in the undepressed position of FIG. 3, the projection 24g is slightly spaced from the surface 26 Similarly, the lower trigger 26 is formed with an upwardly extending projection 26g on its upper end adjacent its inner edge. This projection 2.6g mates with the inner portion of the surface 249 on the lower end of the upper trigger.

In operation, the switching device is grasped in one hand with the reaf edge of the device in the palm of the hand and the fingers engaging the triggers. The lower switch 40 may be actuated independently of the upper switch 39 by depressing the lower trigger 26 with the last three fingers of the hand so that the upper surface 26d of the lower trigger moves inwardly against the urging of the switch button 54 on the lower switch 40, as shown in FIG. 4, to close its circuit. Note that the free end 26b of the trigger 26 moves freely away from the trigger 24.

Referring now to FIG. 5, depressing the upper trigger 24 with the forefinger of the hand moves the free end 24b of the upper trigger 24 inwardly to depress the button 53 of the upper switch 39 and close its circuit. However, the free ends of the triggers move in overlapping paths or arcs. Depressing the upper trigger 24 causes its projection 24g to engage the projection 26g on the free upper end 26b of the lower trigger 26 so that the lower trigger 26 is depressed to actuate the lower switch 40 whenever the upper trigger 24 is moved to actuate the upper switch. The switches 39 and 40 are arranged so that the lower switch is closed no later than the upper switch when the upper trigger is depressed. In the depressed position of FIG. 5, the opposing surfaces 24 and 26 engage throughout their length.

When the switching device is used to control X-ray equipment (not shown), the circuit including the lower switch 40 is connected to energize the rotating anode of an X-ray tube and the upper switch 39 is connected to the circuits controlling the exposure of the X-ray film. Thus, in operation the operator is first supposed to depress the lower trigger 26 to actuate the lower switch 40, and ready the equipment by energizing the motor for rotating the anode of the X-ray tube. Then when the subject is ready to be X-rayed, the upper trigger 24 is depressed by the operators forefinger while the lower trigger 26 is still held closed. Upon completion of the exposure, both triggers are released so that they snap back to their normally open positions in response to the urging of the buttons of the respective switches. If the operator neglects to depress the lower trigger 26 so that the rotor of the anode motor is not operating when the upper trigger is to be depressed, the free ends of the triggers cooperate so that the lower trigger is depressed simultaneously with, or slightly before the upper trigger, thereby actuating the switch 40 and ensuring that the anode is always rotating before an exposure is made. To reduce the likelihood of operator error, the triggers are colored differently, such as black for the lower trigger 26 and red for the upper trigger 24.

Embodiment of FIGS. 6 and 7 One of the features of the invention is that the arrangement shown in FIGS. 6 and 7 is identical to that of FIGS. 1-5 except that there is provided upper and lower triggers 56 and 58 that are formed differently and cooperate diiferently from that of the earlier described embodiment. Except for the triggers, the same numbering of identical components is used.

As can be seen from FIG. 6, the lower end 56b of the upper trigger is formed so that its outer lower corner 560 is in close proximity to the upper outer corner 58c on the upper end 58b of the lower trigger 58. The inner corners 56d and 58d of the free ends of the upper and lower triggers are spaced from each other. The outer faces 56c and 58e of the free ends of the triggers are formed so that either trigger may be depressed without interfering with the other trigger. In other words as shown in FIG. 7, when the upper trigger 56 is pivoted inwardly about its axis to depress the button 53 of the switch 39, its lower outer corner 56c subscribes an arc which just clears the upper corner 58c and the adjacent surface 58e of the lower trigger 58. In the arrangement shown, the end surface 582 of the lower trigger 58 is essentially defined by this are and its extension. However, it should be noted that the entire upper surface of the lower trigger 58 need not be formed as shown, in that it is only necessary that the lower trigger 58 does not interfere with the separate movement of the upper trigger 56.

Similarly, when the lower trigger 58 is depressed to engage the button 54 and operate the switch 40, its outer upper corner 58c subscribes an are which approximately conforms to the lower surface 56e of the upper trigger 56.

It can be seen from FIG. 6 that the arcs described by the corners 56c and 580 of the triggers intersect approximately where the triggers are in their normally open or undepressed positions. Consequently, movement of both triggers simultaneously will cause their corners 56c and 580 to interfere with each other so that neither trigger can be depressed. Thus, if the micro switches 39 and 40 are connected to operate the up and down motion of an electric crane for example, both up and down circuits cannot be simultaneously energized. However, either switch can be actuated independently of the other, as shown in FIG. 7, without any interference.

It should be noted that the mating ends of the upper and lower triggers need not be formed precisely as shown. It is only necessary that when both triggers are depressed, some portion of the opposing surfaces inter-engage to restrict further motion before either switch is actuated. To provide such an arrangement, it is necessary that the arcs described by the outermost portions of the free ends of the triggers intersect before the switches are actuated as the free ends of the triggers are moved inwardly towards a line 59, connecting the pivotal axes 56a and 58a of the two triggers 56 and 58 in that so long as the corners 56c and 58c are moving towards the line 59, they are moving closer to each other.

Embodiment of FIGS. 8-11 The hand-held switch device in the arrangement of FIGS. 8-11 is structurally identical to that of the previous two embodiments with the exception that there is provided a pair of triggers 70- and 72 which are different from those of the earlier arrangements, and there is further provided a rocker element 74 which cooperates with the free ends of the triggers 70 and 72. The triggers 70 and 72 are each respectively provided with an enlarged lobe 70a and 72a which pivots within the mating recesses 16 and 18 formed in the housing as in the earlier arrangements. The free ends 70b and 72b of the triggers are spaced slightly so that either trigger may be depressed without directly engaging the other. The inner surfaces 700 and 72c of the triggers are recessed or formed to receive the rocker element 74.

The rocker element 74 has substantially a T-shaped cross section as seen in FIG. 8 with the elongated upper portions of the element forming a pair of outwardly extending legs 74a and 74b. As seen from FIG. 8, the leg 74a extends between the switch button 53 and the surface 700 of the trigger 70. Similarly, the leg 74b extends between the switch button 54 and the surface 72c of the trigger 72. The third leg 74c of the rocker element 74 extends from between the legs 74a and 74b generally perpendicular to the legs 74a and 74b. The outer end of the leg 74c bottoms against the wall or partition 11a of the housing section 11 which extends between the two switches 39 and 40.

As seen from FIG. 11, the width of the rocker element 74 is approximately the same as the widths of the triggers 70 and 72 with the result that the rocker element is limited in side'ways movement by the housing end wall 12 and the cover section 14 forming the other housing end wall. Inward movement of the element 74, as seen in FIG. 8, is limited by the partition 11a; outward movement is limited by the triggers 70 and 72; and vertical movement of the element as viewed in FIG. 8 is loosely restricted by the switches 39 and 40 in cooperation with the triggers. Thus, the element is effectively confined as shown without the use of any additional fastening means.

-In operation, the rocker element 74 prevents the triggers 70 and 72 from being simultaneously depressed sufliciently to operate the respective switches, in that the inward or sideways movement of the entire element is limited by the engagement of the leg 740 with the partition 11a. Depressing forces simultaneously applied to the rocker element by the triggers through opposite ends of the legs 74a and 74b are essentially balanced. However, when only one trigger, such as trigger 70* is depressed as shown in FIG. 9, the rocker element 74 is pivoted about the leg 740, with the result that the leg 74a mo'ves inwardly sufficiently to depress the switch button 53 and operate the switch 39. This inward movement of the leg 74a causes the opposite leg 74b to pivot outwardly moving the free end of the trigger 72 slightly outwardly. The relationship between rocker element 74 and the trigger ends 700 and 72c and between the surface 72e and the housing wall He at the lower end of the trigger 72 is such that this limited outward movement is permitted. Thus, it will be seen that while the upper trigger 70 is depressed, the rocker element 74 prevents the lower trigger 72 from being depressed.

Referring to FIG. 10, it can be seen that the opposite result is obtained when only the lower trigger 72 is depressed. That is, the force applied against the lower trigger 72 causes the leg 74b of the rocker element 74 to move inwardly pivoting the rocker element about the end of the pivot leg 74c and causing the leg 74a of the rocker element to move outwardly and slightly move the free end 70b of the trigger 70. Consequently, the switch 40 is operated while the rocker element prevents the trigger 70 from being depressed to simultaneously operate the switch 39.

It will be realized that the switching device of the embodiment of FIGS. 8-11 is intended to perform the same switching function as the device of FIGS. 7 and 8, such as controlling the up and down motion of an overhead crane. The arrangement prevents actuation of both triggers at the same time. An advantage of this embodiment is that close tolerances of the components are not required. Both the housing and the triggers may be molded of plastic and the fit between the trigger lobes 70a and 72a and the housing recess as well as other mating surfaces of the components, is somewhat loose and need not be kept within precise tolerances for proper performance. Thus manufacturing techniques are simplified. Also, component wear is less significant when tolerances are not critical.

What is claimed is:

1. A hand-held switching device, comprising:

a housing adapted to be held in one hand;

first and second switches supported by said housing;

a first finger operated trigger extending along one edge of the housing and supported by the housing in a manner such that one end is movable to operate said first switch;

a second finger operated trigger extending along said one edge of the housing and supported by the housing in a manner such that one end is movable to operate said second switch and is positioned adjacent said movable end of said first trigger; and

said triggers being mounted so that in one manner of operation movement of at least one of said trigger ends causes interference with movement of the other and in another manner of operation at least one of the triggers may be moved to operate its switch independently of the other trigger;

the first trigger having a projection which extends into the path of said second trigger; and,

said second trigger having a projection which engages the projection on the first trigger as the second trigger is moved to operate its switch.

2. The switching device of claim 1, wherein said switches are arranged such that the first switch is actuated no later than said second switch.

3. A hand-held switching device, comprising:

a housing adapted to be held in one hand;

first and second switches supported by said housing;

a first finger operated trigger extending along one edge of the housing and supported by the housing in a manner such that one end is movable to operate said first switch;

a second finger operated trigger extending along said one edge of the housing and supported by the housing in a manner such that one end is movable to operate said second switch and is positioned adjacent said movable end of said first trigger; and

said triggers being mounted so that in one manner of operation movement of at least one of said trigger ends causes interference with movement of the other and in another manner of operation at least one of the triggers may be moved to operate its switch independently of the other trigger, the triggers being mounted such that said movable ends cause interference when an attempt is made to operate both triggers at the same time, with the result that neither switch can be operated.

4. The switching device of claim 3, wherein one trigger when actuated is in the path of the other trigger so that only one switch at a time can be operated.

5. A switching device, comprising:

first and second switches;

a first pivotally mounted trigger having a free end for actuating said first switch;

a second pivotally mounted trigger extending generally towards the other trigger and arranged so that its free end is adapted to operate said second switch and is close to the free end of the first trigger;

said free ends having cooperating surfaces arranged so that depressing said second trigger also depresses the first trigger and said second switch is operated at least as soon as said first switch is operated, and so that said first trigger can be depressed independently of said second trigger to operate said first switch.

6. The switching device of claim 5, wherein said first trigger has a projection along one edge of its free end extending toward the second trigger, and said second trigger has a projection which engages the projection on the first trigger when said second trigger is depressed.

7. A switching device, comprising: first and second switches; and first and second pivotally mounted triggers arranged so that the outer faces of their free ends oppose each other; said triggers being independently pivotable from unoperated positions toward operated positions wherein surfaces on said free ends adjacent said outer faces respectively actuate said first and second switches, the arcs subscribed by said trigger free ends intersecting as said triggers are pivoted from their unoperated positions toward their operated positions. 8. A hand-held switching device comprising: an elongated housing; first and second switches supported within said housing; first and second switch triggers pivotally supported along one edge of said housing and movable to operate respectively said first and second switches, either trigger being movable independently of the other to operate its switch; and means associated with said triggers for preventing either trigger from being moved to operate its switches while the other trigger is already moved to operate its switch, said means comprising portions formed on the triggers which interengage to prevent actuation of the switches when the triggers are simultaneously moved but which do not engage when independently moved.

References Cited UNITED STATES PATENTS 2,272,164 2/1942 Neil et al. 200-157 2,410,899 11/1946 Pye 200157 X 2,744,176 5/1956 Kaman ZOO-61.85 X 2,485,340 10/ 1949 Warmey.

2,791,664 5/1957 Rochacs 200157 2,812,405 11/ 1957 Wolkov.

2,985,740 5/1961 Fisher et al. 200-157 3,142,741 7/1964 Bury 200-157 3,198,922 8/1965 Rochacs 200157 3,411,170 1/1968 Kingsley 200-157 X FOREIGN PATENTS 1,148,029 5/ 1963 Germany.

ROBERT K. SCHAEFER, Primary Examiner R. A. VANDERHYE, Assistant Examiner US. Cl. X.R. 200-5, 50

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