US844991A - Portable dynamo. - Google Patents

Description

No. 844,991. PATENTED FEB. 19, 1907.

. G. A. ALLEN.

PORTABLE DYNAMO.

APPLIOATIO N FILED 1336.3,1906.

Mumum,

W/TNESSES INVENTOH WW L610 ATTOHNEyS UNITED sTATEs PATENT GEORGE ADIN ALLEN, or WEsTEEu srRiNes, ILLINOIS, ASSIGNOR TOTHE AETNA POWDER COMPANY, or CHICAGO, itniuois, A CORPORATION OF INDIANA.

PORTABLE D'YNAMO.

Specification of Letters Patent.

Patented Feb. 19, 1907.

Application filed December 3, 1906. .Serial No. 846,139-

- To all whom it may concern.-

ble of being operated Be it known that I, GEORGE ADIN ALLEN, a citizen of the United States, and a resident of Western Springs, in the county of Cook and State of Illino1s, have invented a new and Improved Portable Dynamo, of which the following is a full, clear, and exact descrip-- tion. I

This invention relates to certain improvements in portable dynamos,and more particularly to that type of dynamo used in blasting operationsfor exploding the blasting charges.

The object of the invention is to provide a ignite the electric fuses which are used in exploding the dynamite or other explosive. The type of the device in which the rack-bar is pushed down to rotate the armature has been found far more advantageous in use than any other type and has survived all others for a large number of years.- Thelarge increase in blasting operations, especially in stone-quarries and in railroad construction, has resulted in the demand for larger blasting-machines in order that a greater number of charges might be fired simultaneously.

This demand was at first met by the produc-' tion of a machinecapable of firing from forty to fifty fuses at a time, and this machine has been for a number of years considered to have the maximum capacity v one man and at the same time of a size an Wei ht which would make it easily portable, an therefore commercially valuable. I,

Numerous devices for using gearing-to gain the required number of revo utions of the armature while keeping the length of the rackbar within reasonable limits were tried and of any machine capafound unsatisfactory, because they were too complicated for the ordinary workmen to keep in repair. The current from the electric-lighting dynamo or similar machine could not be used generally, because it required the services of ail-electrician to lay the blasting-wires, inasmuch as the electriclighting dynamo requires a much more com plicated system of wiring. The only choice the manufacturers had, therefore, in the at tempt -to produce a commercially valuable machine was to adhere-to the old type of machine, driven by a rack-bar and pinion;

but great difliculties were encountered in attempting to build a machine of twice the capacity of those formerly employed yet of small enough size to be portable and capable of being operatedby one man.

In order to increase the capacity of the machine, it became necessary to also in crease the diameter of the armature-shaft and of the driving-pinion to properly supportthe armature against the side thrust of the raclebar and to give thenecessary stiffness to said shaft. With the increased size of the armature-shaft and pinion it became necessary to increase the length of the rack-bar to such an. extent that one man could not operate it. In this larger type of machine, which. it was attempted to manufacture, as'well as in most of the smaller machines previously used, the side thrust of the rack-bar against the pinion and shaft of the armature caused a slight bending -of the armature-shaft, and the armature was caused to unevenly rotate and brought nearer to one'pole than to the other. This resulted in very uneven runninr of the ma chine and caused profuse spaflring at the brushes, resulting from the varying of the width of the air-gap between the armature and the poles. Thus it was found practically inipossible to buildalarger machine than those heretofore used While employing the same general design. If the shaft were permitted to remain the same, the armature was not properly supported and ran very unevenly. if the shaft were increased in size, a larger pinion and longer rack-bar had to be used, and this rendered it no longer possible for one man to operate the machine.

By means of my improved construction i am able to build adeviee of twice the ca pacity of any heretofore constructed without increasing the size of thearmature-shaft'or increasing the length of the rack-bar, and'I also reduce to a minimum, if not entirely obviate, all sparking at the brushes, and secure a great improvement in the smoothnessof any machine of this type heretofore. con structed, but'maystill be'easily transferred from place to place and operated man. The invention consists in certain features of construction and combination ofparts, all of .which will be fully set forth hereinafter, and particularly pointed out in the claims.-

Re'ference is to be had to the-accompanying drawings, forming apart of this speciii}.

cation, in which similar characters of reference indieatecorresponding parts in all the figures, in which- Figure 1 is a side elevation of my improved blasting-machine, one side of the easlng being removed to disclose the operating parts. big. 2 is a plan view showing the end of the armature and my improved armatureshaft-supporting means, and Fig. 8 is a perspeetive view of the armature-shaft support.

Devices of the type to which my invention belongs customarily comprise a rectangular casing 10,01 wood or other suitable material,

and having a partition 11 intermediate its ends and serving to support the dynamo. This dynamo comprises an armature 12,

rotating between poles '13 in the upper portion of the casing, said poles being supported by the field-coils 14:, resting on the partition 11. The top of the casing is provided with binding-posts 15,130 which the wires leading to-the fuses are connected, and each bindingpost leads to the field-coils by means of wires 16 and to a switch in the bottom of the casing by means of wires 17. 'A rack-bar 18 is provided for rotating the armatureshaft, and this rack-bar extends through openings in the top of the casing and in the partition 11 and engages with the switch inthe bottom of the casing. The switch is of any suitable type, and preferably comprises a spring 19 and a-binding-post 20, normally in contact, whereby as the rack-bar is pushed down into the casing and the armature is rotated the current generated is short-circuited and may pass freely from one wire 17 to the other wire. As the rack-barreaches the-bottom of the casing it presses down upon the. spring 19 and breaks the contact and causes the current to fiow from onebindingpost 15 through the blasting-line to the other binding-post 15. For properly supporting and guiding the rack-bar there is provided a guide-bar 21 parallel to the rack bar and in engagement with a perforated bracket 22, carried by the latter. As

" the casing the armature 12 is rotating at its the circuit through the switch at the bottom of the casing is normally closed and remains closed until the rack-bar 18 almost reaches the end of its downs'troke, the blasting line is thuSShort-circuited and practically 'the blasting-line. Approximately at the" moment the rack-bar reaches the bottom oi greatest speed, and hence the blasting-line containing the fuses instantly receives. themaxirnum current obtainable from the ma- --chine, and the charges are exploded.

' The armature,- 12 is mounted on a shaft 23 and carries a pinion 2 1, loosely mounted thereon; The oneend of the'pinion is provided with teeth which engage with oppositely dispose'd teeth on the end of the armature, and at the opposite end of the'pinion there is provided a spring 25, normally holding the teeth of the pinion-in engagement with those of the armature. By pushing down on the rack-bar 18 the armature is caused'to rotate; but upon ulling up on the rackbar the pinion moves ongitudinally on the shaft and the teeth slip past each other without causing any reverse rotation of the armature.

In order to support the armature arma- Lure-shaft, and rack-bar, I provide the inn proved'member illustrated in Fig. 3. This member comprises a yoke-casting having longitudinal members 26 upon opoosite sides thereof and adapted to be secured to the opposite poles 13. Connecting the two members 26 are two separate and distinct crossbars or yokes, intermediate of which is provided the guideway for the rack-bar. One

of these cross-bars or yokes 27 carries a bearing 28 of considerably-larger sizethan the armature-shaft'ZS and receives the armature intermediate the teeth and the coil thereof. By making this bearing as large as convenem a greatly-increased bearing-surface is provided, and the center portion of the armature may be increased to any size desired. The second cross-bar or yoke 29 is provided with a bearing 30, adapted to receive the end of the armatureshaft, and this bearing is constructed very much smaller than the bearing 28, the size of said bearing depending upon the size of the shaft employed. As the main weight of the armature is supported in the bearing 28 a very small shaft may be employed and also a inion ofmuch less diameter than would he possible if the entire weight of the armature were supported on the shaft 23 and this shaft made of a size sufficient to pro erly support aid armature. Within the si e of the casting intermediate the bearings 28 and 30 is provided a guideway 31 for the'rack-bar, whereby the latter claim as new and desire to secure by Letters other than in a longitudinal (lire/c l ion.

nearer one pole than the other; but by my adapted. to receive the shaft adjacent iLS end,

eraser.

may be supported in a different relationship to the pinion 24 and prevented 'lrom moving As the raeli bar is pushed down to rotaie the armature there is created a very great side thrust against the armmere-shaft, and there is a strongtendency for this shaft to bend to one side and bring the armature improved construction wherein the armature is supported. by a larger bearing intermediate the opening and the arn'iaiuie and also supported by a second bearing at the end of the shaft no. side movement or bending; of the .arinaturashaft is possible, and the side thrust caused by themoveinent of the racls 1 bar cannot result in other than a perfectly smooth riinning of the armature. By pre venting all. vibration of the arnu rethe sparking at the brushes almost entirely eliminated, and, previously sea-led, I have constructed a device capable of liring' twice the number of charges of any device of this type heretofore constructed, but have still" kept the device Within the limits defined by the required portability and easy of operation.

Having thus described my invention, 1

Patent 1. in combination, a rotary armature, poles supported adjacent thereto, a shaft for said armature, a support for said armature and shaft, comprising a slielel oi'i. l'rah'ie havl ing a bearing adapted to receive the shaft intermediate the armature and the end of lhe shaft, auda second but smaller hearing l a pinion mounted on said shaft intermediate l said. bearings, and a rack-bar in engaeement l with said. pinion and movable in a plane at right angles 'totlie xis of the sl'iaft.

12. In fcoinhination, a re armature, poles supported adj there-to, shaft for said armature, a support for said and shaft, said support comprising bearing 1 adapter; to receive theshaft intermediate the armature and the end of the shaft, a second bearing spaced from the first-mentioned air ng and adapted to receive the shaftedjacent its end, apinion loosely mounted on said shaft inl erined'iale said bearings, means whereby the rotation of the pinion causes the rotation of the armature, and a rack-oar in engagement With said pinion and movable in plane right angles to the axis of the shat 3. In combination, a rotary armature, poles supported adj acenft' thereto, a shaft for said armature, a pinion loosely mounted on said shaft, coacting means on said pinion and shaft, whereby the rotation of the pinion in one direction causes the simultaneous rotation of the armature and shaft, a rack-bar in engagement with said shaft and mow able in a plane at right angles'to the, iLXiSO'f the shaft, and a support for said armature and shaft, comprising a member having portions l poles, a bea'ing for the shaft intermediate the pinion and the ari'natiir e, a second bearing intermediate the pinion and the outer end of the shaft, and a guideway for said rack har.

4. In combination, a rotary armature, a shaft for said arn'iature, a longitudinallyn'iovable pinion on said shaft, said pinion and ai'lnaeure having coacting teeth to cause the simultaneous movement of the pinion and armaiure, a rack-bar in engagement with said pinion and movable in a plane at right angles to the axis of the shaft, a bearing for l the shaft intermediate the pinionand the armature, a bearing for the outer end of the shaft, and a guideway for the racl -bar intewith both of said. hearings. v In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

GEQRGE ADIN ALLEN; il' itnesses:

it. J. "lliinnss, H. A. liicirean,

iereof secured to and supported hythe said

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