Improvements in Mining Drills.
Year: 1888

page_text: Improvements in Mining Drills.
I WILLIAM HENRY JENKINS, of No. 2931 Lawrence Street in the City of
Philadelphia, State of Pennsylvania, United States of America, Mining Engineer 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 mining drills; and it consists in the novel construction and
combination of parts, as will be hereinafter fully described and particularly pointed out in
the claims, reference being had to the accompanying drawings in which figure 1 is a
side view of my improved drill shewing the drill mechanism in a vertical position ;
Figure 2 is a front or face view of the drill, parts being broken away, carrying the
frame; Figure 3 is a top plan view of the same, parts being broken away; Figure 4
is a central vertical section taken on line 4-4 figures 2 and 3. Figure 5 is a detail
view illustrating the drill-operating cam. Figure 6 is a horizontal section on the
line 6-6 in figure 3; and figures 7, 7%, 7b, are detail views of the connecting
discs.
In the accompanying drawings, A denotes a movable frame in which is mounted the
drill rod B and the drill operating mechanism.
To extensions A' A¹, of the frame A are secured stationary slideways CC, in which
is arranged to travel a cross-head D. The cross-head D is formed in two
sections CC, which are provided at their lower interior faces each with a semi-
circular recess cc, having enlarged head-portions e c', which recesses embrace the
upper stem e, of the drill rod B, which is provided with a head e', which fits into the
portions cc, as shown. The slide-ways C are formed with V-shaped grooves d, in
the direction of their length, in which fit to slide therein, V-projections c³ ³, formed
on the edges of the cross-head sections C¹. Upon the outer face of the cross-head D
is secured a U-shaped metal frame F, the arms &d of which extend inwardly and
embrace the stationary slideways CC, and it is provided with a downwardly projecting
portion d', as shown. The frame F is bolted to the cross-head by the bolts bb and
the pin X.

page_text: G, denotes the crank-shaft which is journaled in the frame A, provided upon its
outer end with a suitable crank-handle g, and upon its inner end it is connected with
a hollow disk H, into which is rigidly fixed the cam 1, the specific construction and
operation of which will be hereinafter explained.
The angular extensions or arms d d of the frame F are provided with cam-shaped
openings JJ, formed or the straight portions jj, and the inclines, formed at their
diagonal upper and lower edges with semi-circular seats. By reference to the
drawings, it will be seen that the openings J in the arms dd are arranged in contra
positions i.e. the incline portion of one extends from the upper front edge of the
straight portion downward to the lower, inner edge of the rear straight portion j',
while in the opposite arm the short, straight portion of the opening is at the rear
edge of the arin, and the incline extends from such rear edge towards the front edge.
The purpose of such construction will prosently be described.
l
KK, represent two levers which are centrally pivoted to the fixed ways CC,
one on the under face of each of the said ways C, and have their upper ends
extended and provided with roller bearings which engage the openings in the
arms dd, their lower. ends being extended at kk, which ends are arranged to
automatically operate upon the 'chuck L, secured to the drill rod. These levers
normally rest with their upper ends in the upper semi-circular seats j³, and are
held in such positions by stout flat springs. By reference to the drawings,
it will be observed that the said levers are arranged crosswise in relation to each
other, and that the spring presses against the lower extended portion of one
of the levers, and forces the upper end outward, while the spring
the upper end of the opposite lever, and thus throws said end inward.
The drill-rod B is operated by means of the cam I and the spring M.
operating spring M is what is known as a U-spring, and it is arranged with its
inner leaf m between the ends 1-1 of the frame A, which leaf extends forward
of said ends and rests upon the cross-head before referred to, while its leaf m¹
extends outside the frame and over in line with the leaf m and is fitted over a
screw-rod m³, projecting from an extension 2 of the frame, said screw-rod
being provided with a thumb-nut N, which bears against the leaf m² and by means
of which the tension of said spring may be regulated.
presses against
The
The leaf m, as before stated, extends over and presses against the cross-head,
and such leaf is applied against a knife-edge centre-bearing-plate O, which is
secured in recesses o, formed in the upper ends of the cross-head plates 0 0.
By adjusting the leaf m in the manner described, the greatest possible range is
given to the tension; friction is reduced to the minimum; and the altering and
changing of the spring is accomplished with ease, without otherwise disturbing the
machine.
The drill-chuck L,. which is screwed on the lower end of the drill-rod B, consists
of the hub ', and the enlarged head L², provided with a series of radial pro-|
jections L³, formed with beveled portions 13 on their inner edges.
The peculiar construction of the several parts just described, i.e. the spring, the
cross-head, frame F, the arms K K and the chuck L, and their arrangement, is
such as to accomplish the rotation of the drill in a manner which I will now
describe.
In a previous American patent granted to me, dated February 9th 1886
(No. 335,591) the drill rod is shown and described as operated by a cam, a pin
and a spiral spring, and the rotation of the chuck as caused by a cam-arm attached to
the cross-head, which operates upon the chuck when it is on its upward movement and
theroby causes the same to rotate.
This form of device after some experience was found to be defective, insomuch as
the proper rotation of the clutch was not always accomplished. The chuck was some-
times turned too much, and no positive movement of the same was thereby obtained.
By the construction described in the present case, the rotation of the drill-chuck is
positively accomplished, insomuch as each blow of the drill-rod operates the chuck a
certain degree, and no more or less movement can be communicated to said chuck at

page_text: each movement of the drill-rod, hence the said rotary movement of the chuck and
drill will therefore be always regular. The rotary movement of the chuck L is
accomplished as follows.
The chuck being at its lowest position, the cross-head and pin also at that down or
under position, power is then applied to the crank-shaft, and the cam will begin to act
upon the pin X and start to raise the cross-head and the frame F. As the cross-head
begins to rise, the chuck will be lifted to be disengaged from a stop P, connected to
the frame A, (in a manner presently explained) and before it is entirely disengaged
from said stop P, the head I will engage, with two of its radial projections, with the
lower ends of the arms K, said arms connecting with said head L at opposite sides of
the centre of motion of said chuck, as clearly shown in the drawings. A slightly
further rise of the cross-head will entirely release the chuck from the stop P.
At this time it will be observed that the roller-bearing upper ends of the arms K
will now be at the beginning of the inclines in the openings J in the said arms of
the frame F, and a still further movement of the cross-head and the frame F will cause
the inclines to operate the arms and swing them laterally, until the roller bearings
reach the semi-circular seats in the lower edges of the openings J in the arms d.
The said openings J in the frame, and their relation to the operating crank and pin,
are such that when the cam drops the pin X, the roller bearing will be at the lowest
or inner ends of the openings J, and such movement of the arms K is of a degree
sufficient to turn the chuck one projection or tooth; the roller bearings of the arms
at this time resting against the long, straight portions of the openings J, will
thereby prevent said arms K from further movement, and thus hold the clutch in such
rotated position. Now, as the tension of the spring will be immediately applied as
soon as the cam drops the pin X, the said cross head will be so quickly shot
forward that the roller-bearing ends of the arms will tend to bear against the long,
straight sides of the openings J, and the chuck before it leaves the ends ¹ of the
arms K will have engaged with the stop P, and the portions of the arms being
then entirely released from contact with the chuck, the tension of the flat
springs will cause the upper ends of the said roller-bearing arms to again
assume their normal positions. Thus it will be seen that the chuck after it has
reached its upper movement and has been rotated to the degree described, and when
the cross-head is acted upon by the spring, said clutch will descend in a perfectly
straight line, which is a great desideratum in mining drills. The stop P previously
referred to, which engages the clutch, is a pivotal one, and consists in pivoting a bent
arm Q, as at gl to the frame A, its forward end P arranged to project in line with the
radial projections on the chuck L, and its opposite arm is formed with an upward
extension Q, which is provided with a lock which may be a bayonet or other similar
joint, which connects said arm with a short stud 4 on the frame A, by means of which
the said arm may be readily disengaged from the stud 4, and the stop P thrown
out of engagement with the clutch, as shown in dotted lines, Figure 1. By thus
arranging the stop, it will be noticed that the clutch may thereby be turned either
way when it is desired to make any change in the drills, or for other obvious
purposes.
Near the lower end of the cross-head, I provide the drill-rod B with a collar B₁,
and upon the extensions 5-5 of the frame A, I form a cushion device R, which
consists of a disk r, fitted over the drill-rod B, and a vertical circular metal ring, is
fitted upon said disk. Placed around the drill-rod B, and arranged to rest between
the rings, are a series of circular split rubber rings. By forming the
cushion in this manner, it will be seen that the split rubber rings may be changed,
or their number increased or decreased, without taking apart any portion of the
mechanism, said device forming a cushion against which the rod strikes, and
especially prevents the jar of said rod when the drill strikes a seam in the
rock.
"
39
Upon one side, the frame A is provided with a yoke portion A², which is provided
with a longitudinal dove-tail opening A³, into which is fitted a dove-tail guide S,
which is integrally formed with the main frame T, which is braced within the mine

page_text: and which supports the drill mechanism frame A. The yoke A2 is also provided with
a longitudinal serew-threaded opening A', in which is fitted the feed screw U, which
is passed through the arm T, of the frame T and held to said arm by the collars tt,
and having at its outer end a suitable hand-wheel t³, by the turning of which the
drill frame A is fed forward with the drill.
The main supporting frame T consists of the arms T1 and T2, which are connected
with the dove-tail guide S, the arm T2 having a pivotal connection upon a bolt connected
with a supplemental portion T*, of the frame. T, the other arm T having a pivotal
connection with a U-shaped arm V, which is connected at its end with said
arm T, and at its opposite end with the supplemental frame T4, in a
presently described.
manner
The supplemental frame T, which is arranged to support the weight of the entire
apparatus, and to receive the shock, is provided at one end T, with an adjustable arm W,
which is connected to the said end T by means of the bolt w, passing through
ears of a plate w³, and the end T5, which plate has fixed thereto the screw-rod w³,
upon which the arm W, is adjusted and by means of which the forward end of said
frame T is securely braced to the sides of the mine. The opposite end of said frame
portion T is connected to the column Z, and held thereto in such a manner that
the same may have an approximately universal motion in relation thereto; the
specific construction whereby such result is obtained will presently be explained. It
will, however, be readily understood that when said frame is placed in a desired relation
to the column, the same is securely fixed in such position, and the forward end
braced by the adjustable arm W, the U-shaped arm being also held in a fixed
position.
25
.
As before stated, the main frame T is pivoted upon the supplemental frame T4,
which connection forms practically a hinged connection. This feature forms an
important part of my invention, insomuch as by such arrangement 1 can at any time
swing the main frame which carries the entire drill mechanism, away from the holo
drilled when it is desired to " spoon out the pulverized rock, or when it is
necessary to change the drill bits, or for any other purpose, and when said frame is
swung back, the same will again resume its place without the slightest deviation
from its previous position. To secure said frame T in such position with the
supplemental portion T and yet provide means for easily disconnecting the same,
I construct it in a manner I will now proceed to describe. The forward end of the
arm T2 is formed with a reduced extension T, which is of dove-tail form in cross-
section, and upon the frame T at its forward end I form a projecting portion T,
which fits in the reduced part of the arm T2, and is of a similar shape in cross-section
to the extension T, the two having a hexagon shape in cross-section when united.
Upon the outer edges of the arm T3 are formed guide ribs 10, between which fits
and slides a U-shaped bent spring 11, the forward ends 12 of which are formed to
snugly fit the outer hexagonal portion of the frame arms T and T', and thereby hold
the same in position together. To secure them in such position, I provide the
arm T with an elongated slot 13, through which and the leaves 14, 14, of the spring 11,
is passed a bolt 15 provided with a nut 16, by the adjustment of which nut the
leaves may be securely held against said arm T and thereby hold the parts T² and T
together. If, however, the nut is loosened on the bolt, the said leaves will expand
(see Figure 6) in which case the spring and bolt may be moved back, the bolt
working in the elongated slot until the front ends of the spring are disengaged from
the ends of the arms T2 and T, and thereby permit the main frame and drill
mechanism to be swung on their pivots.
As before stated, the supplemental portion T of the frame T is connected to the
column Z in such a manner as to form an approximately univeral joint, the
construction of which is clearly illustrated in Figure 7 of the drawings.
By reference to said Figure 7, it will be seen that I form the inner edge of the
arm T with a disk 16ª which is provided with a series of circular V-shaped
projections 17, which engage with similar V-shaped grooves 18, formed in the inner
face 19 of a disk 20, which is formed integral with and at the lower end of the

page_text: U-shaped arm V, and which disk is also provided on its outer face with V-shaped
grooves 21, which engage V-shaped projections on the inner face of the horizontal
portion 22, of an angle plate 23, and through said angle plate 23, disks 10 and 20
and the arm T, is passed a bolt 25, formed with a collar 24, entered into a socket 26
in the arm T; said bolt is also provided with a reduced portion 27, upon which is
pivoted the arm T as shown.
By this arrangement it will be seen that by tightening the nut 28, the disks 16ª
and 20 will be secured, and by adjusting the nut 29, the arm T also held in position.
Upon the vertical portion 30, of the angle plate 23 is journaled a disk 31, provided with
V-shaped circular grooves 32. A similar faced angle plate 33, is arranged on the
opposite face of the disk 31, which is also provided with circular V-shaped grooves, and
said angle plates are held for adjustment by a bolt and nut 36 and 37. The angle
plate 33 is provided with a portion 34, which extends vertically but at right angles
to the plate 33, which angle plate is provided with V-shaped projections engaging a
disk 38, having similar grooves 39, engaging the angle plate projections, said disk 38
being provided upon its inner face with lateral ribs 40, 40, between which is fitted
the front end of a connecting bar 41, a nutted bolt 42, passing through said bar,
disk 38 and angle plate, and thus securing said parts together.
The connecting bar 41 extends back to and is journaled on the column Z in any
well known manner, and through its extended end 43, is passed an adjustable brace
bar 44, by means of which and the adjustable brace arm W previously described, the
apparatus is securely braced in relation to the mine walls:
From the foregoing it will be seen that by connecting the frame to the column Z
in the manner described, the frame may have various adjustments. By means of
the disk 31 the frame has a movement back and forward in the direction of the
length of the connecting bar, while by means of the disk 23 and its adjustment, the
frame will have a movement back and forth, at right angles to the connecting bar;
while through the medium of the disk 16" and its adjustments, the frame will have a
movement back and forth horizontally to the other movements described. This
manner of adjusting the frame, as far as I know, has never been accomplished, and
it has been found by experience that by such connection every necessary movement
of the drill frame in drilling, may be obtained.
By reference to Figure 5 of the drawings, the specific construction of the cam I is
clearly set forth, which I will now proceed to describe, previous to which I will refer
somewhat to the construction of the cam device shown in my said former American
patent and thereby point out more particularly wherein my improved construction of
cam differs from the same.
In the construction of the cam in my previous patent, at each revolution of the
cam, the drill rod is lifted twice, and the cam portions being arranged with their
straight faces in diametrically coincident planes, it was necessary to make the pin in
a semi-circular form to permit it to operate in said cam faces.
In the practical
application of the cam described, I have found that when the spring tension was of a
degree to strike but a moderate blow, that the revolution of the cam disk would bring
the lower or beginning portion of the cam groove under the pin, before the rod
reached its lowest point of thrust, and the cam curve being arranged in the manner
described, its bearing surface was brought too near the horizontal diameter, thereby
decreasing the leverage of the cam upon the pin and greatly increasing the friction,
as the leverage upon said pin was nearer to a sidewise than a vertical pressure.
I have found by practical experience that the cam illustrated in Figure 5 will avoid
all of said objections.
The cam I consists of a solid plate of steel securely fitted to the disk H, and
extending beyond the rim of said disk to a distance of about one half its thickness.
In this plate is formed a single cam recess or operating groove I, the heel or
straight portion 1, of which is arranged a short distance to one side of the centre
of the cam. The beginning or point 13, of the curved portion of said groove
commences at a point in the cam periphery at a distance sufficient to permit of the
:
•

page_text: positive fall of the pin X before said point 13 can turn under it. It will be observed
that by extending the straight portion of the cam groove to one side of the centre
of said cam, I add distance between the heel and point of said groove without the
necessity of increasing the curvature of the curved portion of the groove, and thus
avoid additional friction, as each degree of additional curvature to said portion
proportionately increases the friction.
The curved portion 13 is formed of a compound curve, which rises toward and
extends over the centre of said cam face gradually diminishing its radial distance
from the centre, and extending to a distance below said centre is merged into the
straight or heel portion, as clearly shown in the drawing. By arranging the cam
in this manner, it will be observed that but one blow of the drill rod will be accom-
plished at each complete revolution of the cam. It will also be readily understood
that by the formation of the cam groove as described, as the pin X continues to
rise, the leverage upon said pin will gradually increase, thereby compensating for
the additional tension upon the spring.
A still further advantage of forming the heel portion at one side of the central
line of the cam is, that the pin X can be made of considerably more strength,
insomuch as its straight surface is extended beyond the centre and in line with the
heel portion, as shown.
It will also be observed that by the peculiar formation of the cam groove, the
.curved portion will lift the pin from its under side and apply its pressure almost in
a vertical line, and thereby avoid the side pressure which is encountered in the
operation of the cam and pin as described and shown in my previous patent referred
to. This vertical pressure upon the pin is continued through the entire lift of the
pin, while the cam is being rotated.
From the foregoing description, taken in connection with the drawings, the operation
and advantages of my improved drill will be readily understood. It will be seen that
a drill of great capacity is produced, the mechanism for operating the drill heing
of such a character as to adapt the saine to all classes and conditions of rock, and
by the various means of adjustment the same may readily be set. for operation at any
position desired, in drilling."
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed, 1 declare that what 1
claim is
1. The combination, with a drill rod, of a cam for operating the same, which cam
is provided with a groove or recess extending across its face, through and slightly
beyond its centre, one side of which groove is curved from the periphery to the
centre and having a gradually decreasing radius toward the centre of the cam,
substantially as shown and for the purpose set forth.
2. The combination, with a drill-rod having a lifting pin, of a cam for operating
the same, which cam is provided with a groove 1, having a radial side and a
curved side, said curved side extending from the periphery toward the centre, said
curved side having a gradually decreasing radius, said curvature extending over and
past the centre and ending at the inner end of the radial portion, substantially as and
for the purpose described.
3. The combination, with a drill-rod having a lifting pin, of a cam for operating
the same, which cam is provided with a groove I, having a radial side arranged at
one side of the centre line of said cam, and a curved side beginning with its point
at the opposite side of said centre line, extending from the periphery toward the
centre, said curved side having a gradually decreasing radius, said curvature extending
over and past the centre of said cam and ending at the inner end of the radial
portion, substantially as and for the purpose described.
4. The combination, with a cam provided with a cam groove 12, substantially as
shown, one edge of which is formed of a radial, straight portion arranged at one side
of the centre of the cam, of a spring-actuated drill rod, having a lifting pin formed

page_text: with an approximately semi-circular bearing face for operation in said groove, its
opposite face formed straight and extended beyond the centre of the cam, whereby the.
pin is instantly released by the cam when the said straight portion of the pin and the
radial straight side of the groove are in coincident planes, substantially as and for
the purposes set forth.
5. In a mining drill, the combination, of the drill supporting frame, the column Z
for supporting said frame, and a series of adjustable friction disks connecting said
frame to the column, said disks consisting of a horizontal disk 20, vertical disks 31
and 38, said disks 31 and 38 arranged at right angle planes to each other, said
disks 20, 31 and 38 connected to each other by means of angle plates and having
independent adjustments, the disk 20 connected with the main frame, and the disk 8Î
connected with the column Z, all arranged substantially as and for the purpose
described.
6. In a mining drill, the adjusting disks, said disks consisting of a fixed portion
provided with V-shaped projections, and a central portion having internal V-shaped
grooves engaging said projections and arranged between said- fixed portions,
and means for adjusting the several parts together, substantially as shown and
described.
7. In a mining drill, the combination, with the main frame, and a disk 16ª having
V-shaped circular projections formed thereon, secured to the lower edge of said
main frame, of the disk 20, provided with V-shaped circular grooves meshing with the
projections on the disk 16, said disk being formed on the lower end of an extended
arm V of the main frame, the angle plate 23, formed with V-shaped projections
engaging grooves in the outer face of the disk 20, and said angle plate connected by
means of the disks 31, 38, the plate 33 and the connecting bar 41, with the column Z,
substantially as and for the purpose described.
8. In a mining drill, the combination, with the main frame adjustably connected to
a connecting bar, 41, mounted upon the column Z, said har provided with an extended
portion 43, of the adjustable brace bar 44, journaled in the portion 43 of the har 41,
and the adjustable brace bar W, connected to the front end of the bar T of the main
frame, whereby said frame is securely adjusted to the mine walls, substantially as
shown and described.
9. In a mining drill, the combination, with the cam 1, journaled in the frame A;
fixed guides CC, secured in said frame, provided with V-shaped grooves, the cross-
head D, having V-shaped tongues entered in said grooves, and a lifting pin connect-
ing said cross-head and cam, of the U-shaped spring resting against the upper edgo
of the cross-head, and having its opposite end connected with the frame A, sub-
stantially as for the purpose described.
10. The combination, with the cross-head, D), the U-shaped spring M, for operating
the forward throw of said cross-head, one leaf of said spring connected with and
adjustably secured to the frame, and the other leaf extending over the cross head, of
the central bearing plate, secured in the upper end of the cross-head, and provided
with a knife bearing edge, adapted to support the leaf m, of the spring M, substantially
as and for the purpose described.
11. The combination, with the cross-head D, the drill-rod. B, secured thereto, the
chuck secured to said drill rod, the cam for operating the drill rod and cross-head,
said cross-head formed with a cam recess in its edges, of the arms K, pivoted to the
frame, their upper ends engaging the cam recess on the cross head and their lower
ends engaging radial projections on the chuck L, said arms being adapted to oscillate
by the travel of the cross-head, whereby a rotary motion is imparted to the clutch,
substantially as and for the purposes shown and described.
12. In a mining drill, the combination, with the cross-head, the frame F secured
thereto, having lateral arms d d formed thereon, provided with cam shaped open-
ings J, arranged in contra-relation to each other, the drill-rod B, connected to the
cross-head, the chuck L, connected to the drill-rod, and provided with radial projec-
tions, of the swinging arms K, centrally pivoted to the frame A, connected at their,

page_text: upper ends with the cam openings J, and their lower ends arranged to engage the
radial projections upon the chuck, and the canmechanism, substantially as shown and
described, for raising the cross-head, whereby said arms will be oscillated and
thereby rotate the chuck, substantially as and for the purposes set forth.
13. In a mining drill, the combination, with the cross-head, the frame F secured
thereto, having arms projecting therefrom and projecting over the sides of the
cross-head, said arms being provided with cam shaped openings arranged in contra-
relation to each other, the drill rod B, connected to the cross-head, the chuck L,
secured to the drill-rod, and provided with radial projections, of the arms K,
pivoted centrally upon the sides of the frame, and provided at their upper ends with
roller bearings engaging the cam openings J in the arms d, their lower ends k
being arranged to engage the radial projections of the chuck, springs, for
automatically throwing. said arms back to their normal positions, and the cam
mechanism, substantially as described, for operating the cross-head, all arranged as
and for the purpose described.
14. The combination, with the cross-head carrying the drill rod, the chuck attached
to the said drill-rod, the cam mechanism I, substantially as shown and described, for
producing the upward movement of the cross-head, and the spring for forcing said
cross-head down, of centrally pivoted arms, arranged to oscillate by contact at their
upper ends with cam faces of the cross head, their lower ends being adapted to
engage the chuck and revolve the same when said arms are oscillated, substantially as
shown and described.
15. In a mining drill, the combination, with the drill rod, and chuck L having
radial projections, of the pivotal stop P, adapted to engage the radial projections of
the chuck, substantially as shown.
16. In a mining drill, the combination, with the drill rod, and the chuck secured
thereto provided with radial projections, of the pivotal stop P', adapted to engage the
said radial projections, and having an extension Q¹, provided with a bayonet or other
lock joint engaging a stud upon the frame, whereby said stop may be swung out of
engagement with said stud and permit of the rotation of said drill chuck, substantially
as and for the purpose specified.
17. In a mining drill, the combination, with the main frame T, having a dovetail
slide S formed in its length, of the drill frame A, provided with a yoke having a
dovetail recess embracing said slide S, a screw aperture arranged in said yoke portion
parallel to the slide opening, and a feed screw adapted to enter said screw aperture,
and held to rotate in the upper arm T¹ of the main frame and provided with a hand-
wheel, all arranged substantially as and for the purpose described.
18. In a mining drill, the combination with the main frame T, of the drill
frame A, hinged to said main frame, whereby the drill and drill-mechanism may be
swung to one side of the hole being drilled, substantially as and for the purpose
described.
19. In a mining drill, the combination, of the main framo provided with a U-shaped
arm V, forward extended arms T and T, and a supplemental arm T', the arms T
and T suporting the drill frame, said armi T' being pivoted to the outer end, of the
arm V, and the arm T2 pivoted upon the bolt connecting said arm V, with the arm T,
said connections of the arms T', T, permitting the swinging of the frame T and
the drill mechanism away from its working position, substantially as shown and
described.
20. In a mining drill, the combination, with the main frame T, said frame consisting
of the arms T, T and U-shaped arm V, and the supplemental portion T, said arms
having hinged connections at their outer ends to the arm V and frame T, respectively,
the forward end of the arm T being formed with a reduced portion of dovetail shape
in cross-section, the arm T having an enlarged portion arranged to fit the reduced
part of the arm T2, said arm being provided with an elongated slot, of the U-spring
embracing the arm T2, its forward end being adapted to embrace the ends of the
arms T, T, and an adjusting bolt passed through the spring arms and the slot, by the

page_text: adjustment of which the said spring may be slid back and permit the arms T and T
to become disconnected, thereby allowing the frame to be swung upon its pivots,
substantially as shown and described. -
21. In a mining drill, the combination, with the drill-rod, provided with a collar,
and the frame, of the cushion device arranged between said collar, and the frame,
said device consisting of an enlarged ring or collar arranged around the drill rod, a
circular ring or disk arranged at the outer periphery of said collar, and split rubber
rings placed about said rod and adapted to fit between the said rings, substantially as
and for the purpose described.