US1250402A - Electric-hammer switch. - Google Patents

Description

A. WENDELBURG.

ELECTRIC HAMMER SWIT' AIfPLICATlON FILED APR 28. I915. RENEWID SEPT. 20. 1911.

1,250,402 Patented Dec. 18, 1917.

. UNITED STATES PATENT OFFICE.

ALEX WENDELBURG, OF NEW YORK, N. Y., ASSIGNOR 'I'O PITTSBURGH ELECTRIC TOOL COMPANY, OF NEW YORK, N. Y.. A CORPORATION OF PENNSYLVANIA.

BDECTRIC-HAMMER SWITCH Specification of Letters Patent.

Patented Dec. 18, 191 7.

Original application filed July 28, 1914. Serial No. 853,784. Divided and this application filed. April 28, 1915,

Serial No. 24,547.

i To all whom it may concern 'able others skilled in the art to which it appertains to make and useazhe same.

Tl11S invention relates to electric hammers adapted for use in chipping, calking, rivet- -ing, cutting and other work requiring a.

rapid succession of blows upon a. suitable tool. proved form of electric hammer which'is simple fn construction, which may be manufactored at low cost, which is soconstructed as to permit of cooling by immersion in a liquid, which is of comparatively light weight and which possesses such strength and rigidity. as will enable it to withstand the continual jarring to which it is subjected in uscl'.

The invention herein claimed involves the provision bf an improved form of c rcuitcontrolling mechanism whereby the operation of the hammer is governed. This involves the provision of a cavity in the handle of the hammer in which a circuit-brmiln-r of Special form is removably mounted, this circuit-breaker being operable to open and close the circuit to the coils of the hammer. The construction of the circuiflbreaker is such as to insure a. good ctlntact when the opemtin handle of the switch is movedto the close position and to minimize the clan ger of arcing at the terminals by the pro "ision of auxiliary contact surface which' effect a delayed breaking of the circuit.

The invention also involves numerous other features of improvement in the construction of the hammer whereby great strength, good wearing qualities and ample protection of the parts are obtained. These and other features of the invention will be better understood by reference to the folowing description taken in connection with the accompanying drawing which shows the prefegred embodiment of the invention li ereiu claimed;

.' In the drawing, Figure l is a central sec- Renewed September 20, 1917.

The intention is directed to an ini-"" Serial No. 192,413.

tional view of a hammer embodying my invention;

Fig. 2 is an enlarged sectional view. through the circuit-controlling mechanism;

Fig. 3 is a transverse section of the circuitcontroller on line 33 of Fig. 2; and

Fig. i is a diagram of the circuit connection.

Referring to these drawings, the frame of the hammer consists primarily of a tubula casting l and a handle casting 5. The cast. mg -l is of nonmagnetic material, preferi ably phosphor bronze, and the tubular passage therethrough contains a reciprocating solenoid core or plunger 6, ada ited to strike the end ofa. tool to be. inserte through the hollow tool-guide 1- l,herein'aftr mentioned. The casting l is proigided with radially disposed walls 7, '8 and-,9, which provide spaces between them for'solenoid coils 10 and 11. These coils are -wound in opposite directions and serve to'develop magnetic fields which actuate the plunger 6 constitutin the core of the soleiioid. The'coils are inc ose-d by. a casing 12 which is preferably a piece of steel tubing. This tubing and the walls 7, 8 and 9. are of'such dimensions that the tubing fits snugly around the walls, and the spaces between the walls, 7, 8 and 9, and the casi 12 are completely filled by the coils 10 51% 11. The forward-ends of-the casting 4 and the casing 12 are connected together by a nozzle 1". For this purpose, the projecting 0nd of the casting 4 is provided with an ex terior thread with which the nozzle l3 coacts and the nozzle is formed with a projecting flange adapted to fit tightly over the end of the casing 12, as shown. The forward end of the hammer is provided with a tool-guide 14 of slightly smaller internal diameter, so that the plunger cannot slip out. This toolguide is preferably formed to fit into the end of the casting 4' and have threaded engagement with the end of the nozzle 13. By this construction, the forward ends of the casting and the-casing 12 are rigidly connected by the nozzle 13 so as to preclude relative moveu'ient of these parts, and the nozzle effects such a tight fit with the guide and cos- 'ing as will preclude the entrance of a liquid central passageway through the casting 4 is provided with an enlargement for a cushioning spring 16 to receive the blow of an impact block 15. A portion ofthis block lies within the tubular passage through the casting 4 in which the strikiu g plunger 6 reciprocates.- The remainder of the block 15 is of larger diameter and lies Within the en largement of the tubular passage. The coiled spring 16 bears at one end upon the block 15, the latter being provided with a peripheral flange 17 encircling the end of the spring so as to hold the latter against lateral movement. Between the larger portion of the block loand the Wall at the end of the enlarged'chamber is a washer 18 of tool steel which receives the blow of the block 15 when the latter is returned by the spring 16. The opposite end of the enlarged chamher is closed by a cap 19 which has threaded engagement with the wall of the casting 4. The exteriorly threaded flange on this cap serves as a retainer coactin with the end of spring 16 to hold the latter in position. This flange and the similar flange 17 on block 15 prevent side motion of the spring so that chafing of the spring upon the walls of its inclming chamber and consequent lack of uniformity in the action of the spring are prevented. Y

The casting for the handle 5 has a central opening therethrough in which the rear ends of the casting 4 and the casing 12 are received. For securing these parts together, the casing 12 may conveniently have a sleeve 2-0 secured thereon by means of rivets and forming a circumferential flange. The end 21 of the handle casting 5 closely incloses the end of the casing 12 and is exteriorly threaded to coact with a ring or collar on which is a lip 23 adapted to engage the flange 20. lVhen the sleeve 22 is screwed up tightly, the end 21 of the handle casting and the lip 23,'both of which closely inclose the casing 12, engage the "flange 20 on opposite sidcsthereof and grip the handle'casting 5 to the casing 12. The casting 5 is also interiorly threaded to coact with a threaded plug 24 which fits closely around the adjacent end of the casting 4,

- its end abutting against a flange 25 thereon.

In this way, both the casing 12 and the casting a are connected to the handle casting 5 and these connections are such tight ones that they not only afi'ord the necessary degree of strength, but also precludethe pas- ;'sage of water through them.

The plug 24 is pro ided with a hole through the centertherem as are also the caps 19 and 15. Because of this Provision,

' air may pas freely from the space between the block 15 and the striking plunger 6 as radial slot from end to end as is shown for circuit-controller with his thumb. The parts of this circuit-controllerare located within a tube of insulating material and may all be assembled within this tube before the latter is inserted in its cavity within the handle casting. Also, the parts of this circuit-controller are especially constructed so as to provide for a hard rubbing engagement of the contacting surfaces and a delayed break of the circuit zit-auxiliary contacts. The

construction cf'the circuit-controlling apparatus is shown more clearly in Fig. 2. In the bottom of the cavity in the handle casting 5 are a washer 26 and block 27 of insulating material both of which are removably held. in place by a screw 50, as shown in dotted lines in Fig. 2. In the insulating block 27 are two'contacts 28, which have wires connected thereto which passthrough a passage 29 formed in the casting 5 and are connectedto terminals upon a l of insulating material'which is'secured upon ock 30 the castingli'n the space between the. latter I and the end-of the casing 12, The contacts 28 are adapted to be en aged by the, endsof pins 31 located in a cy 'ndrical block 32 of insulat i'ng material which is secured in the end or'. tube 33 of insulating material of a size adapted to fit snugly within the cav-- ity formed in the casting 5, v This block 32 is secured to the tube 33 by one or more pins 34. The-opposite'ends of the pins 31 are threaded into contacts 35 which are of semi circular form. and are secured upon the block 32 directly opposite each other. The

ends of these contacts'35jrising from the block 32 are spaced apart. and on their ads acent sides theyLare provided with inclined curved depressions as shown at 36. (Fig; 3). Z

- second block 37 ofins'ulating material is secured in position'w'ithin' the tube 33 and forms-a guide for a; movable cont-act carrier 38. This carrier has the contact 39 secured thereon, this contact being in the form ofv a cup or bell theskirt of,whic h is slotted so a as to form a pluralitybfr resilient contact fingers. The contact-carrir'38 has a cavity formed therein -which'- receives a spring 42 bearing upon a washer of heat-insulating material resting onthe enlarged end 43 of a 'short rod 44 carrying an auxiliary contact 1-5. This auxiliary contact is of conical form as shown. The rod 44 is adapted to 'slide in the opening provided for its recepmay also any water which enters this sp'ace.- The plungerfi is preferably provided with a tion in the contact carrier 38. The spring, 42, being inclosed in a chamber whose walls are of heat-insulatingmaterial, is correspondingly protected against loss of temper due to the heat of sparking at the contacts when the current is broken; a spring -11 is interposed between the black 37 and :rflange of the stem 53 of insulating material hav ing at its top a press buttonto. When the parts of the circuit-controller have been assembled within the tube 33 of insulating material, the latter is moved into the cavity in the handle 5 and the end of that cavity is inclosed by a threaded cap 47. t

The! wires for carrying current to and from' the hammer enter the structure through a passage 48 provided in the handle casting 5. A connection block 49 of in sulating material carrying three terminals insulated from each other-is preferably prowhich block the wires leading to the hammer are connected.

The wiring for carrying current to and from the hammer is illustrated 'diagrammatically in Fig. 4. By reference'to' Fig. 4, it will be noted that two of the wires or conductors pass from terminals on the insulating block 49 to the block of insulating material 30, and, from said block 30 are con tinned by other wires until they are connected respectively to the non-adjacent ends of the coils 1" and 11. The adjacent ends of these coils are connected together, and, from their point of connection, a wire leads to the block 30, and is continued by another wire from the block 30 to one of the contacts 28. From the other contact 28, a. wire leads to the third terminal upon the insulating block 49. These nnections are such that the connection from the junction of the two coils '10 and 11 to the other side of the circuit may be opened or closed by the circuit-breaking mechanism located in the cavity of the handle, since this connection is made through the contacts 35 which are connected or disconnected by the bell 39 and auxiliary contact 45. In Fig. 4, the insulating-"block 30 is shown as provided with.

indii'idual grooves for the reception of the several wires or-co: doctors referred to. In assembling and disassembling the hammer, the wires leading from the insulating block 419 and from one of the contacts 28 to the insulating block 30 can be electrically connected with the continuations of those 'wires respectively by means of suitable connecting and disconnecting screws 56, as will be readily understood. y I

When the button lti'is pressed, the contact 39 and auxiliary contact are: moved .forward are; the latter engages the inclined'sun faces 36 upon the contacts 35, so closing the circuit. continued, the auxiliary contact 45 is moved him relative .to the contact carrier 38 thereby compressing the spring 42. As this takes place, the contact 39 moves 0\ er the contacts by the arts Asthe movement of button 46 is 35 so as to effect an electrical connection between them. -By reason of the resiliency of the slit-ted skirt of the bell-shaped contact sp ing 41 forces the contact carrier 38 and the contact 39 upwardly so as to interrupt the connection of the contacts 35 by the contact 39. While this is taking place, however, the auxiliary contact 45 does not im- .mediatelv disengage the contacts 35 for the riderl upon the (lasting 5, at this point, to reason that it is still kept in contact with them momentarily by the spring 42. After the contact 39 has moved away, however, a distance sufiiclent to clear contacts 35, the

contact 45 disengages these contacts so as to break the circuit. As a; consequence, whatever arcing there is takes place between the contact 45 and the surfaces 36, and has no effect upon the surfaces of contact between the-slit bell 39 and the outer peripheries of" the contacts 35, which therefore remain'constantly bright and "in efiicient conductive condition.

The circuit-breaker herein described may be readily constructed at low cost by assenb' bling the parts within. the insulating tube 33 and thereafter inserting that tube in the cavity in the handle of the hammer; In OFGIMJQII, this circuit-controller serves to c ose and o n the circuit effectively", a good contact of arge Surface area t of the contact 39120 inclose thetwo contacts 35- and the contact 45m spitead thecontacts 35 into hard en- .ga ment; with the contact 39 mg insured t will be noted that the'construction of the hammer is such as will permit of coolmg it by the whole ofthe forward portion of theihamme'r in a cooling li uid.

Elie coils 10 "and 11 are so inclosed'an the connections between the inclosing parts are such that the entrance of the'cooling 1i uid into the chambers for the. ,coils'is preclu ed.

To further insure this result, the flange 57 is brazed to the: shell or casing 12, and a thin asbestos gasket 58 'is'inserted at the point indicated; in addition 'towhich the screw-threads connecting the nozzle '13 to the end of the 'castin 4 and to the toolsguide 14 may be shellack before assembling the.-

parts, thereby making absolutely water-tight f joints. Furthennor the'parts of the hammer are connected together with such strength and rigidity that the continual and severe jar- -ring incident 'to the useofth'e hammer will not cause the parts to, work loose. The tool steel washer 18 which.receiyes the return blow of the block is fixed in position within its cavity. preferably by shrinking it in place, in order that it may not follow the upward movement of said block.

--I claim:

1. In an electric h nnner, the combination of a pair of yielding contacts, a plunger, a slotted bell carried by said plunger and movable to embrace and bridge said contacts, and means for spreading said contacts against the inner face of said hell.

2. In an electric hammer, the combination of a pair of yielding contacts, a springpressed plunger, a metal bell carried by said plunger and movable therewith to embrace and bridge said yielding contacts, and a wedge-shaped conductor adapted to enter between and spread said yielding contacts,

substantially. as described.

3. In an electric :hammer, the combination of a pair of yielding contacts, a-springpressed plunger, a slotted metal bell carried by said plunger and movable to envelop and bridge said yielding contacts, and an auxiliary contact member yieldingly mounted on said plunger and adapted to enter between and bridge said yielding contacts.

a. In an electric hammer, the combination of a pair of yielding contact members, a sliding spring-pressed plunger, a. conductive element carried bysaid plunger and adapted to engage the outer faces of said contact members and form a bridge between said members, and a spring-pressed rod mounted in said plunger and adapted to enter between said contact members and spread the same against the inner face of said element, said rod being slidingly mounted and pro-. jecting from said plunger far enough to give a delayed break when said plunger moves its conductive element out of engagement with said contact members.

5, In a hammer handle, adigitally. operated plunger, a bridging bonductorearned by said plunger, a. pair {if contacts to be bridged thereby, a springpressed rod slidingly mounted in said plim 'ger, said ro'dhaving an auxiliary tapering contact adapted to enter between said first named contacts before their engagement with the bridging bridged contacts when said plunger is withconductor, said auxiliary-contact giving a delayed break for current between said drawn. y

An electric hammer handle having a cavity, a pair of contacts located therein, a,

member movable in said cavity and carrying a conductor adapted to inclose and yieldingly. embrace said pair of contacts, an auxiliary contact mem er slidingly mounted in said movable member and adapted to enter between said pair of contacts and electricall y connect the same when said member moves inward, and a. spring permitting rela contacts in said tu tire movement of said auxiliary contact member to delay the interruption of the circuit between said first-named pair of contacts when said movable member moves outward, substantially as described.

7. In an electric hammer, a handle having a cavity therein, a tube of insulating material in said cavity, a pair of contacts located in said tube, a movable member having a contact of circular form located thereon adapted to engage and connect said contacts, and a movable springactuated contact upon said movable member-adapted to enter between said contacts and spread the same, substantially as described.

8. In an electric hammer, a. handle having a cavity therein, pair of contacts fixed at the base of mid cavity, a tube of insulating material removably mounted in said cavity, a pair of' contacts located in said tube, and adapted to be detachably connected with said first-mentioned pair of contacts, a digitally operated member movable in said tube and carrying a contact adapted to inclose and yielding] embrace said pair of be, an auxiliary contact member slidably mounted in said movable member and adapted to enter between said air of contacts in said tube when said memr moves inward, and a spring permitting relative movement of said auxiliary contact member to delay the interruption of the circuit when said movable member moves outward; substantiallyas described.

9. In an electric hammer, a handle having a cavity therein, a'tube of insulating material in said cavity, a pair of yielding contacts located in said tube, a digitally operated plunger movable in said tube and carrying a slotted bell adapted to inclose and yieldingly embrace said pair of contacts, said plunger beingprovided with a' chamber, a spring in saidchamber, and an auxiliar contact member engaged by said spring an slidingly mounted in. said plunger, said auxiliary contact member being adapted to enter between said pair of contacts'and spread the. same against the inner faceof the bell when the plunger moves inward and giving a delayed break for current between the pair of contacts when said plunger moves outward. I i

10. In an electric-hammer, a handlehaving a cavity therein, a pair of contacts located in said cavity, each of said contacts being of semi-circular outline, a digitally operated plunger movable in said cavity and carrying a. slotted bell adapted to inclose eing provided with a chamber therebetween when the plunger moves mward and before said bell reaches said contacts, the spring within said plunger permitting relative movement between said auxiliary contact and said-slotted bell, and giving a delayed break for current between said pair of contacts when said plunger moves outward in said cavity.

11. In an electric hammer, a handle hav-. a tube of insulating ing a cavity therein,

material in said cavit ,a pair of contacts located in said tube, a movable member having a contact located thereon adapted to en age and connect said contacts "and a movabfia spring-actuated contact upon said movlocated in said tube, a mova mg a 'contact located thereonfladapted, to

able member adapted to enter between said 1 contacts.

12. In anelectric hammer, a handle having a cavity therein a tube of insulating material-in said cavity, a 1Emir of contacts le'member hav- 20,

engage and connect said contacts and a movable spring-actuated contact upon said movable member adapted to enter between said contacts and spread the same. 25

In testimony whereof I aflix

Images