US3814886A

US3814886A - Miniature electrical reversing switch mounted on trigger operated switch for hand-held tools

Info

Publication number: US3814886A
Application number: US00331969A
Authority: US
Inventors: E Piber
Original assignee: Cutler Hammer Inc
Current assignee: Cutler Hammer Inc
Priority date: 1973-02-12
Filing date: 1973-02-12
Publication date: 1974-06-04
Anticipated expiration: 1991-06-04
Also published as: FR2217783B3; GB1436275A; FR2217783A1; DE2359292A1

Abstract

A miniature electrical reversing switch is disclosed for a power tool trigger switch wherein separate pairs of fixed contacts in the switch circuitry are selectively bridged by bridging contactors to reverse current flow therefrom to the tool motor. The contactors are mounted on a movable slide member which is part of a compact one-piece integral plastic molding also including an integral flexible hinge and external knob operator. The knob operator is mounted concentric with the trigger lock pin bushing and is manually rotated about the base thereof for coaction with the flexing hinge to impart linear sliding action to the slide and bridging contactors relative to the fixed contacts.

Description

United States Patent 1191 Pibera June 4, 1974 MINIATURE ELECTRICAL REVERSING SWITCH MOUNTED ON TRIGGER OPERATED SWITCH FOR HAND-HELD TOOLS 7 5] Inventor: Earl T. Piber, Oconomowoc, Wis. [731 Assignee: Cutler-Hammer, Inc., Milwaukee,

Wis.

[22] Filed: Feb. I2, 1973 [21] Appl. No: 331,969

[52] US. Cl. 200/157, 200/1 V [51] Int. Cl. l'l0lh 13/08, HOlh 19/36 [58] Field of Search 200/157, 1 V, 6185; 310/68 A; 173/l70 [56] References Cited UNITED STATES PATENTS 3,376,402 4/19ss Bednarski 200/157 amt/x01 9/1969 Matthews... zoo/1v x 3,725,624 4/1973 Emmons 200/157 FOREIGN PATENTS OR APPLICATIONS 927.322 5/1963 Great Britain 200/1 V Primary Examiner-Robert K. Schaefer Assistant Examiner Robert A. Vanderhye arne 41491 THq h R- Ra hsr Wm-HA: Autio 5 7 ABSTRACT A miniature electrical reversing switch is disclosed for a power tool trigger switch wherein separate pairs of fixed contacts in the switch circuitry are selectively bridged by bridging contactors to reverse current flow therefrom to the tool motor. The contactors are mounted on a movable slide member which is part of a compact one-piece integral plastic molding also including an integral flexible hinge and external knob operator. I

The knob operator is mounted concentric with the trigger lock pin bushing and is manually rotated about the base thereof for coaction with the flexing hinge to impart linear sliding action to the slide and bridging contactors relative to the fixed contacts.

10 Claims, 9 Drawing Figures PATENTEUJuu 4 1914- SHEET 3 BF 3 BACKGROUND OF THE INVENTION This invention generally relates to electrical reversing switches for power tools and the like and more particularly to improvements therein that contribute to miniaturization of such switches and economies of manufacture.

Various switches have been devised for power tools and household appliances to reverse the direction of rotation of the electric motor for such devices. By way of background, it may be observed that the manufacture of these switches is exceedingly competitive necessitating that cost thereof be kept to an absolute minimum. At the same time, however, manufacturers of such switches are called upon by their customers to supply switches of improved quality as compared to switches used in the past. Moreover, in addition to cost considerations, existing switches are generally complicated and bulky requiring a considerable amount of space within the tool.

.Consequently, the design of reversing switch constructions has been an extremely active field in recent years, the primary aim of this activity being to improve such switches by reducing the number of required component parts and by making them smaller, more durable and dependable and less costly and adaptable to applications having certain size limits.

SUMMARY OF THE INVENTION The general object of the present invention is to provide an improved reversing switch of the type described which circumvents the problems heretofore noted as well as other disadvantages of the prior art. I

More specifically, it is an object of this invention to provide a durable miniature electrical reversing switch for tools and appliances which is capable of manufacture at low cost, has a minimum number of parts and so designed to be readily and easily assembled in mass production operation.

These and other objects and advantages will become more apparent in the following specification and claims when read in conjunction with the appended drawings.

DETAILED DESCRIPTION OF THE DRAWINGS In describing the present invention, reference will be made to the accompanying drawings forming a part of the instant invention wherein:

FIG. I is an elevation view partially broken away of a power tool handle mounting a trigger switch embodying the miniature reversing switch of the present invention.

FIG. 2 is a perspective view of the miniature reversing switch in FIG. 1 shown in combination with a known trigger switch.

FIG. 3 is an exploded view in perspective of the miniature reversing switch of FIGS. I and 2 constructed in accordance with the present invention.

FIG. 4 is a bottom view of the miniature reversing switch housing illustrating internal structural details with one fixed contact in place.

FIG. 5 is a cross sectional view of the switch illustrated in FIG. 4 taken along line 5-5 of FIG. 4 illustrating the flap in the closed position.

FIG. 6 isa front view of the reversing switch in FIG. 4, FIG. 7 is a plan view of the contact carrier and knob actuator assembly with the contactor strips in place.

FIG. 8 is a schematic illustration of the tool motor and switching circuit embodying the present invention and illustrating tool motor operation in the FOR- WARD direction of rotation.

FIG. 9 is a schematic illustration of the tool motor and switch circuit embodying the present invention and illustrating tool motor operation in the REVERSE" direction of rotation.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. I of the drawings, there is shown therein a power tool of the portable type indicated generally at 10 having a trigger operated switch 12 incorporating a miniature motor reversing switch 14 constructed in accordance with the instant invention.

The tool illustrated is of the type which incorporates a depending pistol grip handle 16 having

switches

12 and 14 mounted therein. Handle 16, which may be formed of cast aluminum or of a rigid high impact plastic material is separable into two sections and is provided with conventionally formed

projections 0r ribs

17 and 18 which entrap switch 12 and with an aperature 22 through which linearly slidable trigger 24 of switch 12 extends. Handle I6 is also provided with a hole 26 in the side wall thereof through which a conventional lock pin 28 of switch 12 extends and is further provided with a hole 30 in the bottom wall thereof through which the insulated power supply leads 32 and34 extend. Leads 32 and 34 connect switch 12 to a suitable power source (not shown).

The construction and operation of switch 12 is similar to that illustrated and described in H. W. Brown US. Pat. application Ser. No. 233,621 filed Mar. I0, 1972 entitled Butt Contact Speed Control Trigger Swieh," now abandoned. As explained therein and shown in FIG. 2 of the drawings, switch 12 includesan insulating base 42, a switch frame 44fo'r securing trigger 24 to base 42, a lock pin 28 mounted on switch frame 44 and a helical compression spring (not shown) within switch 12 to bias trigger 24 externally of base 42. Upon actuation of trigger 24, contacts (not shown) within switch 12 are bridged closing the circuit to supply current over

leads

48, 50, 52 54 and 56 to energize motor 36.

Having briefly and generally described the construction and operational features of a conventional power tool anda known trigger switch therefor, 21 unique and inexpensive miniature switching device for reversing the direction of motor rotation by coacting with the aforementioned switch 12 and motor 36 will now be described in more detailwith like parts being indicated with like character references throughout the specification and several views.

Referring generally to FIGS. 1 and 2,v miniature motor reversing switch 14 is shown mounted atop frame 44 of switch 12. It should be noted at the outset that switch 14' utilizes a very efficient and compact double pole sliding bridge assembly to accomplish the motor reversing function and that such arrangement measures a mere 7/16 inch by 1 /8 inch dimension by /8 3 inch high, approximately. Further, while a double-pole sliding bridge switching arrangement will be used to illustrate the invention, it will be apparent to those skilled in the art, that the structure disclosed herein can also be used for other types of switches such as a double-pole double throw type or other varieties of single and multi-pole switches.

Referring now in particular to FIG. 3, illustrating the individual reversing switch elements in exploded view, switch 14 is provided with an insulating housing 60 constructed of a suitable electrical insulating material such as a moldable thermoplastic and has

pins

62 and 63 molded integral therewith to locate housing 60 in a predetermined position atop frame 44. The pins are received in two

holes

64 and 65 during assembly of housing 60 to frame 44 and may either be staked or deformed by heat to firmly secure housing 60 to frame 44.

Internally, housing 60 has a'plurality of spaced apart insulating shoulders 66 molded therein as shown in FIGS. 3 and 4 to form recesses or depressions 68 in housing 60 which are adapted to receive and retain

individual spring contacts

70, 71, 72 and 73. Contacts 70-73 are constructed of a good electrical conducting material such as copper and are individually secured within depressions 68 adjacent external housing openings 74 near the backside of housing 60 by an integrally hinged cover or flap 76 having an interlocking member 78 in interference fit with shoulder portions 79 in housing 60 upon closure of flap 76 as shown in FIG. 5.

Contacts 70-73 have openings 82 and83 and lead retainer springs 84 at one end to receive, secure and adjust

leads

48, 50, 52 and 54. The lead ends are inserted through

openings

74 and 82 and are trapped therein by the retainer springs 84. Stops 91 on flap 76 limit inward travel of the leads through the openings past springs 84. Access depressions 92 including thin penetrable membranes of thermoplastic material are molded integral with housing 60 directly in-line above holes 83 in contacts 70-73 to permit penetration for external manipulation of the retainer springs 84 relative to the leads without having to disassemble switch 14. The membrane serves to shield live electrical conductors from the environment and may be easily plugged after having been pierced.

Contacts 70-73 also have offset conducting portion 93 opposite the lead receiving end of the contacts extending from depressions 68 into slide cavity 80 to engage a sliding contact carrier assembly 95 externally operable through an open ended portion 96 of housing 60.

The carrier assembly 95 is a one-piece thermoplastic molding of generally rigid insulating material having good structural strength such as nylon and includes a slide 98, a flexing hinge 99 and a knurled knob actuator 100.

Slide 98 is provided with a detent projection 101 integrally formed on the side thereof as shown in FIGS. 3 and 7 for interlocking with detent recesses or depressions 102 and 103 in the flexible'side wall 104 of housing 60 for releasibly securing slide 98 in either forward or reverse modes of operation. Slide 98 also includes an integral stop member 105 bounded by cavity 106 within housing 60 to prevent overtravel of detent projection I01 past depressions 102 and 103.

Slide 98 is further provided with

recesses

107 and 108 molded in the topside thereof to receive and

secure contactors

110 and 112 generally flush therewith as shoulder 113 of portions flap 76.

Knob actuator 100 includes an abutment or interlock pin 114 integrally molded on the periphery thereof and is adapted for coaction with spaced

slots

116 and 118 in the trigger 24, necessitating movement of actuator 100 to either one of the two positions as shown in FIG. 2, to enable the trigger 24 to be depressed or moved inwardly of switch frame 44. It can readily be seen that trigger movement will be blocked for all other actuator positions by the central shoulder portion 120 of trigger 24.

The knob actuator 100 also includes a central bore 122 to permit mounting thereof concentric about the lock pin bushing 123 and extends externally from the side of handle 16 with lock pin 28 in a position to be actuated. It is to be noted that this arrangement requires no additional auxiliary openings in handle 16 and that the existing handle lock pin hole 26 need only be slightly enlarged to accommodate knob actuator 100. Thus, it is readily apparent that rotation of knob actuator 100 about bushing 123 will cause flexing hinge 99 to move contactor slide 98 to bridge selected pairs of contacts -73 with

contactors

110 and 112 to cause motor 36 to run tool 10 in either the forward or reverse direction of rotation upon actuation of switch 12.

It will be seen, therefore, that for forward rotation of knob actuator 100, as is illustrated in FIG. 8,

contacts

70 and 73 are bridged to connect leads 48 and 54 and

contacts

71 and 72 are bridged to connect leads 50 and 52. In such position and upon closure of switch 12, current flow is established to motor 36 from switch 12 through lead 48 to contact 70 of switch 14 which is bridged by contactor 110 to contact 73. Current flows therethrough and over lead 54 to motor armature terminal 126 and reenters switch 14 from motor armature terminal 128 through lead 60 to contact 71. The bridging of

contacts

71 and 72 by contactor 112 completes the circuit through lead 52 to motor field terminal 130 and back to switch 12 via motor field terminal 132 and lead 56.

Similarly rearward rotation of knob actuator causes shifting of contactors and 112 relative to conducting portions 93 of contacts 70-73 as shown in FIG. 9 to cause motor 36 to run tool 10 in the reverse direction of rotation upon actuation of switch 12. In such position,

contacts

70 and 71 are bridged to connect leads 48 and 50. Likewise,

contacts

72 and 73 also are bridged to connect leads 52 and 54. As can readily be recognized-this shifting will cause motor 36 to run tool 10 in the reverse direction of rotation upon trigger actuation since the manner of introducing current to armature

terminals

126 and 128 has been reversed.

It is to be noted that modification to the carrier assembly 95 for reversing switch 14 hereinbefore described and shown in FIG. 7 may also be made. For example, an elongated reversing lever overlying trigger 24 of the type shown and described in U.S. Pat. No.

3,260,827 to C. J. Frenzel may be molded integral with or mechanically attached to flexing hinge 99 replacing knob actuator 100. Pivoting of such a lever on the top side of housing 60 would, upon actuation, impart linear reciprocal sliding motion to slide 98 through hinge 99. Moreover, thumb actuated levers of the type described and shown in U.S. Pat. No. 3,376,402 to T. E. Bednarski may also replace knob actuator 100 and be pivoted on the top side of housing 60 to operate slide 98.

From the foregoing, it will be apparent to those skilled in the art, that the present invention provides a substantial improvement in reducing the number of component parts for reversing switches for power tools and appliances. lt will also bereadily recognized that such reduction of parts coupled with the unique arrangement and interaction of those utilized provides a highly efficient and durable miniature switch which is inexpensive to manufacture and readily adaptable to existing tools without the need for extensive or expensive tool handle modifications or for additional complicated wiring during the assembly stage of such tools.

While the apparatus hereinbefore described is effectively adapted to fulfill the objects stated, it is to be understood that the invention is not intended to be confined to the particular preferred embodiment of the miniature motor reversing switch disclosed, inasmuch as it is susceptible of various modifications without departing from the scope of the appended claims.

I claim: I

1. In combination, a power tool comprising:

a tool housing;

motor means mounted therein;

switch means on said tool for energizing said motor means in forward and reverse operation modes; lock means on said tool for locking said switch means in selected positions of actuation; and,

wherein said switch means further includes actuator means having a portion of which is mountable on said lock means exposing a portion of said lock means to permit independent operation of each, said actuator means being operable with said switch means to cause said motor means to operate in either a forward or reverse operating mode.

2. A tool according to claim 1 wherein said switch means comprises a first switch for energizing said motor means and a second switch including said actuator means for selecting the operating mode, wherein said lock means is operatively connected to said first switch, and wherein said second switch is in circuit and operatively connected to said first switch.

3.1A tool according to claim 1 wherein said lock means includes a lock pin bushing and a lock pin extending generally laterally of said housing, wherein said actuator means is a cylindrical knob having a central bore for mounting concentrically about said lock means for movement relative thereto and wherein said lock pin extends through said bore to permit independent operation thereof relative to said actuator means.

switch means in said frame having a trigger actuator which is operable, upon actuation, to energize a tool; lock means mounted transversely of said frame and operable to lock said trigger actuator in selected positions of actuation; and

wherein said switch means further includes actuator means having a portion of which is mountable on said lock means exposing a portion of said lock means to permit independent operation of each, said actuator means being operable with said switch means to cause reversal of operating power to a power tool.

5. A trigger switch according to claim 4 wherein said lock means includes a lock pin bushing and a spring biased lock pin extending therethrough and generally laterally of said frame, wherein said actuator means is a cylindrical knob having a central bore for mounting concentrically about said lock means for movement relative thereto and wherein said lock pin further extends through said bore to permit independent operation thereof relative to said actuator means.

6. A trigger switch according to claim 4 wherein said trigger actuator further includes a plurality of slots and shoulders formed on a side face thereof, wherein said actuator means further includes interlock means which coact with said slots and shoulders to prevent said actuator means from being actuated to reverse power through said switch while said trigger actuator is in an actuating state.

7. A trigger switch according to claim 4 wherein said switch means further comprises:

switching means within a housing mounted on said frame being operable when energized to power said power tool in either a forward or reverse operating mode, said switching means comprising: a plurality of fixed contacts within said housing; contactor means adapted to conductively bridge selected fixed contacts to cause reversing of current through said switching means to said tool; and,

carrier means for operating said contactor means comprising:

slide means for supporting said contactor means in bridging relationship with said fixed contacts; and

hinge means interconnecting said slide means and actuator means and being responsive to move said slide means in response to movement of said actuator means.

8. A switch according to claim 7 wherein said lock means includes a lock pin bushing and lock pin extending generally laterally of said frame, wherein said actuator means is a generally cylindrical knob having a central bore for mounting concentrically about said lock means for relative movement to said actuator means.

9. A switch according to claim 7 wherein said fixed contacts have resilient retainer means for securing lead means thereto and wherein said housing has access means adjacent said contacts to permit adjustment of said retainer means relative to said lead means without having to disassemble said reversing switch.

10. A switch according to claim 7 wherein said carrier means is an integral one-piece thermoplastic mounting.

mg STATES PATENT OFCE "CERTIFICATE OF (2033,91

aa=m 35814386" Q MM June 1974' .4

T. Piber I I 1 is pertiijid that rror appears in the above-identified patent F; 394 that; sgglc l'Lgttgra Patent are hereby corrected as ahown below:

Column 2, line 43, "Swich" should be Switch "how abandoned." should be and assigned 'to the assignee of this J'Jrwentiona colu -4, lineaa, "6o" should be so Column 5, linejffih "operation" should be operating Signed and sealed this 28th day of January 1975."

I (SEAL) Attest:

nccoy GIBSON JR, v o c.- SHALL DANN Arresting Officer- Comissioner of Patents jgfigg srwr s PATENT owm CERTIFICATE 0F COBREQ'VITI N E'en i9 3,81%886: I Dated '4 974 inventor) Earl T. Piber above-ic'ientified patent It is gertified that error appears in the d as shown below:

' god that said Letters Patent are hereby correcte Column 2, line 43, "Swich" should be Switch now abandoned." should be and assigned to the assignee of this invention.

Column 4, line 46, "60" should be 50 Column 5, line 34, "operation" should be operating Signed and sealed this 28th day of Jenner-y 1975.

(SEAL) Attest:

McCOY M. GIBSON JR. 0. MARSHALL DANN Attesting Officer Conunissioner of Patents

Claims

1. In combination, a power tool comprising: a tool housing; motor means mounted therein; switch means on said tool for enerGizing said motor means in forward and reverse operation modes; lock means on said tool for locking said switch means in selected positions of actuation; and, wherein said switch means further includes actuator means having a portion of which is mountable on said lock means exposing a portion of said lock means to permit independent operation of each, said actuator means being operable with said switch means to cause said motor means to operate in either a forward or reverse operating mode.

3. A tool according to claim 1 wherein said lock means includes a lock pin bushing and a lock pin extending generally laterally of said housing, wherein said actuator means is a cylindrical knob having a central bore for mounting concentrically about said lock means for movement relative thereto and wherein said lock pin extends through said bore to permit independent operation thereof relative to said actuator means.

4. A trigger switch for a power tool, the switch comprising: an insulating frame; switch means in said frame having a trigger actuator which is operable, upon actuation, to energize a tool; lock means mounted transversely of said frame and operable to lock said trigger actuator in selected positions of actuation; and wherein said switch means further includes actuator means having a portion of which is mountable on said lock means exposing a portion of said lock means to permit independent operation of each, said actuator means being operable with said switch means to cause reversal of operating power to a power tool.

7. A trigger switch according to claim 4 wherein said switch means further comprises: switching means within a housing mounted on said frame being operable when energized to power said power tool in either a forward or reverse operating mode, said switching means comprising: a plurality of fixed contacts within said housing; contactor means adapted to conductively bridge selected fixed contacts to cause reversing of current through said switching means to said tool; and, carrier means for operating said contactor means comprising: slide means for supporting said contactor means in bridging relationship with said fixed contacts; and hinge means interconnecting said slide means and actuator means and being responsive to move said slide means in response to movement of said actuator means.