Improvements in Electrical Reciprocating Tools.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements in Electrical Reciprocating Tools.
I, WILLIAM PRICE CARSTARPHEN, Jr., of Room 36 Masonic Temple,
Denver, County of Arapahoe, State of Colorado, United States of America,
Electrician, do hereby declare the nature of this invention, and in what manner
the same is to be performed to be particularly described and ascertained in and
by the following statement :-
My invention relates to an improved electrical tool provided with a reciprocating
plunger located and moving within the tubular spools of two coils or sets of coils
of insulated copper wire through which a direct current of electricity is alternately
passed. This reciprocating plunger is preferably constructed of pure soft iron
because of its great capacity for conducting the magnetic lines of force or its
permeability to these lines. The hollow or tubular cores, or the helices should be
constructed of some non-magnetic material possessing the requisite durability.
I prefer to construct these spools of brass, which possesses in a satisfactory degree
the qualities stated.
The current for operating my improved tool may be supplied from any suitable
electrical source, as the ordinary galvanic battery, or dynamo-electric machine, and
this current is simultaneously switched from one coil or set of coils to the other
by the use of a mechanism located between the two coils or sets of coils and
controlled by the reciprocation of the plunger. The reciprocating motion of this
plunger results from alternately producing a strong magnetic field at different
points in its path in the manner heretofore intimated.
The principle of the improvement and the mechanism by which it is applied will
be fully understood by reference to the accompanying drawing, wherein is illustrated
an embodiment of the invention. In this drawing,
Fig. 1 is a side elevation of the tool ready for use.
Fig. 2 is a similar view with the casing and bit removed.
Fig. 3 is a side view partially in section. This view is obtained by giving the
tool a quarter turn toward the right from the position illustrated in Figs. 1 and 2.
Fig. 4 is a longitudinal section taken through the centre of the tool without
cutting the plunger.
In Fig. 5 the tool is shown with the casing removed and several coils wound on
the spool which is divided into sections by insulating disks.
Fig. 6 is an enlarged view in detail of one of the switch brushes, and Fig. 7 is a
horizontal section of the same.
Fig. 8 is an outline top view of the switch without the brushes.
Fig. 9 is a side view of the cylindrical contact breaker forming an element of the
switch.
Fig. 10 is a plan view of a stationary plate located in the bottom of the switch
box, and Fig. 11 is a side view of the same, the box or casing being shown in
section.
Fig. 12 is a longitudinal section taken through the casing and showing the
manner of fastening the tool.
Fig. 13 is a transverse section taken on the line x-x, Fig. 12.
In these views wherein similar reference characters designate corresponding
parts of the mechanism let the numerals 10 and 10º designate two hollow spools
placed end to end and suitably connected, the inner end flanges being sufficiently
separated from each other to permit the intermediate location of the automatic
switch meohanism and allow the plunger the required length of stroke. Besides
the switch box which is secured to the adjacent extremities of the spools 10
and 10%, these spools are otherwise connected by strengthening bars or stays 11.

page_text: The brass spools 10 and 10% are wound with suitable copper wire which may
form a single coil or several coils as may be desired. In the single coil construction
shown in Figs. 2 and 3, one end 12 of the wires leads to a metal brush 13 secured
to a rectangular metal frame 14 having two opposite sides made fast to the adjacent
ends of the spools. The free extremity of the brush 13 engages a rotating
cylindrical circuit breaker 15 centrally pivoted to the bottom plate of casing 14.
The corresponding extremity 12 of the opposite coil leads to a similar brush 13
secured to the switch box on the opposite side from brush 13. Brushes 13 and 13*.
engage the circuit breaker 15 at diametrically opposite points. This circuit
breaker is provided with a metal contact plate 16 partially encircling its body
portion which is composed of suitable insulating material. Plate 16 is shown in
dotted lines in Figs. 3, 5, and 8.
The circuit breaker 15 is provided with a wrist 17 formed in its lower end to one
side of its centre or pivotal point and engaging a recess 18 formed in a sliding
plate 19 supported upon the bottom of the switch box and provided with
downwardly projecting arms 20 which pass through slots 21, 21 formed in the
bottom of the box. The reciprocating plunger 22 is located in the central
space 23 of the hollow spools and crosses the space between the spools just below,
or to one side of the switch mechanism. Centrally located upon this plunger is a
circumferential shoulder 24 adapted to engage arms 20 of plate 19 as the plunger
reciprocates, thus moving said plate sufficiently to give the circuit breaker a partial
rotation. This movement alternately makes and breaks the connection between the
metal contact plate 16 and the brushes 13 and 13. Hence these brushes never
simultaneously engage said contact plate.
The outer extremities 24 and 24 respectively of the respective coils lead to a
circuit wire 25 connected with a binding post 26 and thence with one pole of the
electrical source through the medium of a wire 27. A wire 28 leads from the
opposite pole of the battery or other source of electricity to the binding post 29
and thence through a wire 30 to a metal conductor 31 having its extremities
secured to the spools but insulated therefrom. A wire 32 leads from conductor 31
to a third metal brush 33 secured on one side of the switch box, and having its free
extremity constantly in engagement with the contact 16 of the circuit breaker. The
binding posts are insulated from spools 10 by an insulating plate d.
It will thus be seen that the electric current is always completed through one of
the spools 10, 10, and that these spools are alternately in the circuit. In following
the current I may say that it passes from one pole of its source through wire 28,
binding post 29, wire 30, conductor 31, wire 32 to brush 33 and thence to the
contact plate 16. Now if brush 13 is in contact with plate 16 the current passes
through this brush, through the coil wound on spool 10, thence to wire 24, wire:25,
binding post 26 and wire 27 to the opposite pole of its source, completing its
circuit. Or if brush 13ª is in contact with plate 16 the current passes thence through
said brush, through the coil wound on spool 10ª, through the wire 24 and wire 25
to the binding post 26, completing the circuit as last described. Since the current
is always completed through conductor 31 I divide this part so as to form a narrow
space 48 between its parts, and I bridge this space by a sliding contact 49
manipulated by the use of a button 50 connected by a neck 51 insulated from the
contact as shown at 52. This contact breaker is manipulated at pleasure by the
user of the tool, the button 50 being located on the outside of the casing and
the neck moving in a slot 53 formed therein.
The ends of part 31 on each side of space 48 are slightly raised while the under
surface of the contact 49 is correspondingly concaved. By virtue of this construc-
tion the parts are held securely in contact when space 48 is bridged and the
contact may be easily moved to one side of the space when it is desired to break the
circuit. When the tool is in operation the electric current alternately traverses the
two parts just described, one coil being in each path. As the current passes
through one of the coils the attraction resulting from the lines of force induced by
the current, drives the reciprocating plunger 22 into the hollow of the coil to the

page_text: limit of its stroke. This action of the plunger shifts the contact breaker by virtue
of the construction heretofore described and cuts the coil just traversed by the
current out of the circuit, and completes the circuit through the other coil. Again
the attraction resulting from the induced lines of magnetic force acts on the
reciprocating plunger and draws it back into the hollow of the other spool when
the contact breaker is again shifted and the reciprocation continues.
The manner of insulating the switch brushes from the parts to which they are
attached is shown in Figs. 6 and 7. Let y designate the brush, which may be
either that designated as 13, 13ª or 33 when occupying their proper positions in the
mechanism. One extremity of the brush being bent to lie parallel with the
surface to which it is to be secured is placed upon an insulating plate 8 engaging
one side of the switch box. A screw 7 having its head countersunk in the opposite
side of the switch casing is passed through apertures formed in plates 8 and the
engaging extremity of the brush, these apertures being large enough to receive an
insulating rubber sleeve 6 surrounding the screw. Let X designate the conductor
leading to the brush, which conductor may be that designated as 12, 12ª, 30 or 32
in those views wherein the parts are assembled. This conductor surrounds the
insulating sleeve and engages the brush. Above the conductor is placed an
insulating washer b, and these parts are all secured in place by a small nut 9 which
the outer extremity of the screw is fashioned to receive.
In the smaller styles of my improved device where a short stroke is always
desirable, the reciprocating plunger should always be separate and distinct from
the chuck stem as shown in Fig. 4. This division is indicated by the line 35 in
said fig., and 36 is the chuck stem which is provided with a collar 37 located in a
small chamber 38 enclosed by a cup-shaped casing 39 secured to one end of the
spool 10. The stem 36 is provided with a feather or spline 36ª engaging a corre-
sponding groove formed in casing 39. This construction allows the stem a free
longitudinal movement, but prevents any rotating action. Between the collar 37
and the other end of the casing is located a coiled spring 40 which normally holds
the chuck stem at its backward limit of movement. As the reciprocating plunger
engages the inner extremity of stem 36 the latter is driven forward to the pressing
spring 40. As soon as the plunger releases the chuck stem, the latter is returned
to its normal position by the recoil of the spring. This chuck should be constructed
of non-magnetic material so that it will neither adhere to the plunger nor to the
external para-magnetic objects.
Experience has shown that the adjacent extremities of the plunger and chuck
manifest little or no wear after use for a considerable length of time. This condition
results from the fact that the plunger in its rapid reciprocation compresses the air
in the hollow of the spool 10" and forms an air cushion between its extremity and
the adjacent extremity of the chuck. Hence this cushion or column of compressed
air prevents, it is believed, the actual engagement of the adjacent parts of the
plunger and chuck between which it lies, and accounts for the absence of wear
between these parts.
.
In Fig. 3 the chuck stem is shown continuous and integral with the plunger.
In the larger style of tool for mining purposes this form would undoubtedly be
preferable. In this case the bit, of course, moves the entire length of the stroke.
The outer portion 45 of this continuous plunger, beginning at a line 46 should be
formed of non-magnetic material to prevent the magnetization and consequent
trouble from its adhering to external para-magnetic objects, and for the further
purpose of utilizing to the best advantage the lines of force induced by the current
circulating through the coils.
As heretofore stated, the plunger proper should be of pure soft iron which is
delicately sensitive to the induced magnetic action, since it has a high co-efficient
of electro-magnetic conductivity or is readily permeable to the lines of magnetic
force. It is obvious that the magnetic action induced by the current in passing
through the convolutions of the one coil will continue to draw the plunger until
-the inner entrance to the hollow spool is equidistant between the extremities of the

page_text: plunger, when the magnetic action will cease to be efficacious in continuing the
movement, since the poles of the plunger are equally acted upon by the polarity
induced at the inner entrance of the hollow spool whose coil is in the circuit, which
polarity repels one pole of the plunger and attracts the other. Hence in order to
get the best results the length of the permeable portion of the plunger should be
so regulated that the extremity lying in the direction toward which it is moving
will, when at the forward limit of movement, be nearer the inner entrance to the
hollow of the magnetizing coil than the opposite extremity of the plunger. This
is illustrated in Fig. 4, and though in Fig. 3 the part 45 is continuous with the
permeable soft iron bar, the line of demarcation between the non-magnetic
portion 45, and the permeable portion should be located to correspond with line 35
in Fig. 4, when the bar 22 and the chuck stern are in contact. I will assume that
46 designates this line in Fig. 3.
In many cases it will be found desirable in a tool of this class to change the
speed without altering the current which induces the magnetic energy. I accomplish
this by the use of the construction illustrated in Fig. 5. Instead of winding the
spool from end to end, layer upon layer, forming a single coil as shown in Figs. 2
and 3, I divide the spools 10 and 10 into several sections, spaces or compartments
by the insulating disks 55. As shown in the drawing I use two disks on each spool
and form three compartments or sections 1, 2, 3. Compartment 1 is first wound
full and then compartments 2 and 3 successively in the order named, the three
coiled sections being composed of continuous wire, but each section being wound
.full before the wire is carried to the next. The innermost sections are wound
first and then the others in their order toward the outer extremities of the
spools.
The ends 12 and 12ª of the coils are connected with the brushes 13 and 13"
respectively as heretofore described, while the circuit wire 30 is carried directly
from the binding post to brush 33 and the wire 25 to a bar 61 secured to the
adjacent extremities of the spools, but insulated therefrom. About one half of
this bar is formed into ridged sections 62, 63 and 64 insulated from each other and
from the other portion of the bar as shown in 65. The last convolution of coil 1
is connected by a wire 67 with ridge 62 which is located nearest the circuit
breaker 60. The last convolution of each coil 2 is connected with the central
ridge 63 by a wire 68, and the last turn of each coil 3 with the outer ridge 64 by
a wire 69.
As shown in Fig. 5 one extremity of circuit breaker 60 engages an insulating
division 65 and the circuit is broken. Part 60 is concaved on its inner side, its
extremities only being in contact with other parts and is adjusted by sliding back
and forth. For this purpose it is provided with a button 50 connected with the
part by a suitable neck adapted to move in a slot 53 shown in Fig. 1. One
extremity of the part 50 is in contact with the body of the bar 61 while the inner
extremity is fashioned to engage the ridges 62, 63 and 64, and is sufficiently
yielding to permit of its being easily moved from one of the contact ridges to the
other and when in place it grips the ridge tightly enough to prevent possible
displacement which otherwise might result from jars or vibrations of the parts
.while the tool is in action.
I will suppose the cylindrical circuit breaker 15 to occupy the position shown in
Fig. 5, that is, with the contact plate 16 engaging brush 13. Now if part 60 is so
adjusted that its contact extremity engages ridge 62 the current may be said to
pass from one pole of the electric source through wire 28, binding post 29, wire 30,
brush 33, contact plate 16 and brush 13 to one extremity 12 of the coils 1, 2, 3 of
the spool 10, and thence back and forth through all the convolutions of each layer
of coil 1, and out through conductor 67 to contact ridge 62, through part 61 and
wire 25, binding post 26 and wire 27 to the other pole of the electric source,
completing the circuit. It will thus be observed that when part 60 engages contact
ridge 62 the current only passes through section 1 of the coil. Now if part 60 be
moved to engage contact ridge 63 the current passes through section 1 of the coil

page_text: as before, but as the circuit cannot now be completed via wire 67, the current
passes to and through the next coil 2 and thence out through conductor 68 to
contact ridge 63 aud thence completing the circuit, through part 60 as before..
Again if part 60 is shifted to engage contact ridge 64 the circuit cannot be
completed ria wire 68 hence after the current has traversed coil sections 1 and 2 it
will pass through coil 3 and thence out through conductor 69 to contact ridge 64,
completing the circuit via part 60 as before.
It will be observed that by reason of its arched shape part 60 when engaging
contact ridges 63 or 64 spans 62, or 62 and 63 as the case may be, thus being never
in contact with more than one ridge at the same time.
The cutting bit 75 is secured within a suitable socket formed in the chuck. As
shown in the drawing this socket is rectangular in section and tapers gradually
from the entrance to its inner extremity where it communicates with a transverse
key hole 76. The bit stem is fashioned to correspond with the shape of the socket
and made of such size as to wedge tightly therein and extend into the keyhole.
The key 77 is located immediately in the rear of the bit and engages the same.
The surface of the key engaging the bit is inclined while, the opposite face lies in a
vertical or horizontal plane according as the tool occupies a vertical or horizontal
position. The head of the key is larger than the opening for its reception, being
provided with a projecting lip which prevents its falling through the opening before
it is engaged by the bit. Its smaller extremity is provided with a pin 78 to prevent
the key from slipping out in the opposite direction. When it is desired to remove
the bit it may be easily loosened by tapping the head of the key with a hammer.
Within the rear extremity of the central opening in spool 10 is a resilient
buffer 80, which is engaged by bar 22 when at its backward limit of movement
or during its reciprocation. This buffer reduces the concussion or jar to a minimum
and by its recoil action gives the stem a forward impetus. and thus assists in the
return movement.
The mechanism is enclosed in a cylindrical casing preferably formed in two
sections A and B, as shown in Fig. 1. These sections are united in any suitable
manner, preferably by a screw joint, C indicating the line of demarcation between
the body portions of these sections of the casing. These two parts may overlap
by telescoping the one into the other sufficiently tightly to be held together by
frictional contact. Or one may be interiorly threaded and provided with a
shoulder, and the other correspondingly exteriorly threaded, thus forming
joint. I have found by experiment that it is advantageous to have this external
shell constructed of some material having a high coefficient of magnetic induction,
as soft iron.
a screw
The button 50 projects from one side of this outer shell as shown in Fig. 1, while
the binding posts 28 and 29 protrude from one end thereof. This shell is insulated
from the binding posts and from all parts of the mechanism lying within the circuit.
The switch box 14 also projects from one side of the casing and is closed by.a
cover secured in place in any suitable manner.
From the foregoing description the construction and operation of my improved
electric tool will be fully understood. This instrument may be constructed of small
size so that it can be easily held in the hand when used. This small sized tool will
be found highly advantageous in cutting marble and other stone, and specially so
in cutting inscriptions on tombstones, monuments, etc. It is also believed it will
prove a valuable acquisition to the sculptors tools and greatly facilitate all fine
stone-cutting work. The tool can be cheaply operated for light work, since a
battery consisting of a few cells will supply current of ample strength, and when
once set in motion its action is thoroughly automatic.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is :-
1:- In an electrical tool the combination with two hollow coils of a movable

page_text: .
bar supported therein, a circuit and a commutator located between the coils and
consisting of a box or frame connecting the two coils and provided with a bottom
located just above the movable bar and a top covering the working parts, a movable
plate supported upon said bottom and provided with depending arms projecting
through slots formed in the bottom of the box and into the path of the bar which is
provided with a shoulder adapted to alternately engage said arms as the bar
reciprocates, a cylindrical circuit breaker pivoted in the bottom of the frame or box
and provided with a wrist or projection located to one side of its centre and
engaging a slot formed in the movable plate, a single contact plate secured to said
circuit breaker and partially surrounding the same, the upper extremity of the
circuit breaker being pivoted to the top plate of the box, and three brushes, one
constantly in engagement with the contact plate and the other two alternately in
contact therewith, the brushes and the coils being arranged and connected in the
circuit, substantially as described and for the purpose set forth.
2nd-In an electrical tool the combination. with two hollow coils, a movable
bar supported therein, a circuit, a commutator located between the coils and con-
sisting of a box or frame connecting the coils and provided with a bottom located
just above the movable bar and a top covering the working parts, a movable plate
supported upon said bottom and provided with depending arms projecting through
slots formed therein and into the path of the bar which is provided with a shoulder
adapted to alternately engage said arms as the bar reciprocates, a cylindrical
circuit breaker consisting of a block of insulating material having an exposed
metallic contact plate partially surrounding the same, said circuit breaker being
pivoted in the bottom of the frame and provided with a wrist or projection located
to one side of its centre and engaging a slot formed in the movable plate, the upper
extremity of the circuit breaker being pivoted in the top plate of the box, and
three metallic brushes, one continually in direct engagement with the contact plate
of the circuit breaker, and the other two alternately in direct contact therewith,
the brushes and coils being arranged and connected in the circuit substantially
as shown and described whereby as the movable bar reciprocates a partial rotation
in reverse directions is imparted to the circuit breaker, as and for the purpose
set forth.
3rd The combination of two hollow coils enclosed by a suitable metallic shell or
case, each coil being wound in a plural number of distinct sections by the use of a
continuous wire, a movable bar supported in said coils, a circuit and automatic
switch mechanism connected with the coils and lying within the circuit, and a
movable spring plate suitably supported upon the tool and located within the shell
or case, said plate having one extremity continually in electrical contact with one
pole of the source of electricity, metallic contacts lying in the same plane and equal
to the number of sections of each coil, these contacts being insulated from each
other and each connected with a single corresponding section of both coils by a
continuous conductor, said contacts forming a series of corrugations which the
spring plate is fashioned to engage, and means connected with the movable spring
plate and protruding through a slot formed in the enclosing case whereby said plate
may be shifted at will from the outside of the shell independently of the movement
of the reciprocating bar according as it is desired that the current shall pass through
one or more of the coil-sections, substantially as described.
4th-In an electrical reciprocating tool the combination with two hollow ener
gizing coils, of a movable bar supported in said coils, a circuit, switch mechanism
located between the coils and projecting into the path of a movable bar which acts
directly thereon, said switch mechanism consisting of a circuit breaker composed of
a solid cylindrical block of insulating material and a single exposed metallic
contact plate partially surrounding said block, and three metallic brushes, two of
the brushes being respectively connected with the coils and alternately in engage-
ment with the contact plate of the circuit breaker, the third brush being electrically
connected with one pole of the electrical source and constantly in engagement with
..the contact plate of the circuit breaker whereby the current is alternately passed

page_text: through the coils and a reciprocating movement imparted to the bar, substantially
as described.
5th-In an electrical tool the combination with two hollow energizing coils, of a
movable iron bar supported therein, a circuit in which the coils lie, a commutator
located between the coils which are suitably separated therefor, said commutator
consisting of a cylindrical circuit breaker composed of a solid block of insulating
material partially surrounded by a single exposed metallic contact plate, and three
metallic brushes, two of the brushes being respectively connected with the coils and
alternately in direct engagement with the contact plate of the circuit breaker, the
third brush being connected with one pole of the electrical source and constantly in
direct engagement with the contact plate of the circuit breaker, a sliding plate
connected with the circuit breaker and having arms projecting into the path of the
movable bar, said bar being provided with a ring or shoulder adapted to engage
these arms and actuate the circuit breaker whereby the current is alternately
passed through the coils and a reciprocating movement imparted to the bar,
substantially as described.
6th In an electrical reciprocating tool the combination with two hollow
energizing coils of a movable iron bar supported therein, a circuit in which the
coils lie, a switch mechanism located between the coils which are suitably separated
therefor, said mechanism consisting of a circuit breaker composed of a cylindrical
insulating block partially surrounded by a single metallic contact plate and three
metallic brushes, two of these brushes being respectively connected with the coils
and alternately in direct engagement with the contact plate of the circuit breaker,
the third brush being connected with one pole of the electrical source and constantly
in direct engagement with the contact plate of the circuit breaker, a sliding plate
connected with the circuit breaker and having arms projecting into the path of
the movable bar, said bar being provided with a shoulder centrally located
thereon and adapted to engage these arms and actuate the circuit breaker, giving
the same a partial rotation in reverse directions whereby the current is alter-
nately passed through the coils and a reciprocating movement imparted thereto,
substantially as described.
Dated this 5th day of May AD 1892.
WILLIAM PRICE CARSTARPHEN, JR.