Improvements in Lifting Dogs and the like Appliances.
Year: 1896

page_text: Date of Application, 31st Oct, 1896
Improvements in Lifting Dogs and the like Appliances.
I, GEORGE HOGGART, of 283, Earsham Street, Sheffield, in the County of York,
Boiler Maker, do hereby declare the nature of my said Invention to be as follows:-
Although my Invention is applicable to a variety of purposes, such as lifting,
pulling and hauling, it is more particularly applicable for lifting plates, such
as boiler plates, ship and armour plates and the like.
The ordinary methods employed for lifting such articles, say for example, a
boiler plate, is to employ a screw dog which is provided with jaws to receive the
edge of the plate, a screw passing through one of the jaws enables the dog to
be secured to the plate by the tightening of the screw, the dog is also provided
with a ring or shackle by which it may be slung to a crane chain or other lifting
tackle, and suspended.
When so suspended a plate is sometimes subjected to a succession of jars and
vibrations either in the act of moving or during the hammering whilst under
inspection or by some process such as drilling, punching, rivetting or the like.
In such cases the plate is liable to slip out of the jaws of the dog through the
loosening of the screw caused by the jars and vibrations above referred to.
Now the object of my Invention is to obviate this defect and to construct a
dog which, instead of becoming loose when the article to which it is attached
is subjected to jars, vibrations or other strains, shall grip the article more tightly
and become more securely fixed thereto.
I effect this in the following manner;
I provide my Improved lifting dog with a screwed stud on each jaw, the ends of
such studs, which project through the inside of the jaws, instead of being convex
or round ended, I form slightly concave so as to increase the frictional resistance
against the surfaces of the article to be lifted. The portion of the studs which
project to the outside of the jaws of the lifting dog I form with hexagonal
octagonal or polygonal cants of suitable proportions to the size of studs employed.
On the studs, beyond and to the outside of these cants, I provide a short length
of additional screw.
For the purpose of actuating the said studs as well as for the purpose of sus-
pending the dog, I employ on each stud, a link one end of which fits like a close
ended spanner on to the canted portions of the same, the other end of the link
I form with an eye or ring large enough to receive a chain or other suitable sling.
I curve or bow both the last named links, above the dog, so that their eyes
On
or slinging ends are brought closer together when opposite to each other.
the projecting portion of the studs already referred to beyond the cants, I
provide nuts, pins, cotters, or other suitable means by which what may be called
the key end of the link may be secured to the stud and prevented working off
when in use.
OL
Innowed lifting dor is as follows

page_text: Say for example a boiler plate had to be lifted. The screw studs in the jaws
of the dog, which by preference I should make right handed, would be left wide
enough apart to allow of the edge of the plate to pass between them deep into the jaws
of the dog. The link on one side of the dog would then be placed in a horizontal
position (or at an angle approximating thereto), to the left (looking towards the
stud).
The stud on the opposite side would then be tightened by its link until a firm
grip of the plate had been made. If in effecting this the link should happen
to come in line with or to a corresponding opposite angle to the first named link,
the plate may then be slung from the eye or ring end of the links as already
described when the weight of the plate would tend to draw both links into a
vertical position and thereby further tighten the studs in the jaws of the dog.
If the last named link did not come quite to the required position when screwed
up by hand, it would be taken off the canted part of the stud and moved on to
another cant which would bring it into the required position. All that would
be necessary to effect this would be to temporally remove the nut or other fastening
by which the link is secured on to the stud.
As a modification of the arrangement herein described instead of forming the
studs with cants to receive the key end of the lifting links I provide them with
ratchet wheels and the links I provide with ratchet pawls so that the studs may
be tightened and slackened by means of such ratchets, the tightening action
when suspended being the same when the ratchets are employed as that already
described in the previous arrangement.
As a further modification, when plates of very great weight have to be lifted,
such as Armour plates, I sometimes construct my Improved lifting dogs with
longer jaws and with four or more studs instead of the two herein previously
described, each pair of studs acting in a similar manner to that already described.
Dated this 30th day of October 1896.
R. HEBER
RADFORD,
Agent for the Applicant.
Improvements in Lifting Dogs and the like Appliances.
I, GEORGE HOGGART, of 283, Earsham Street, Sheffield, in the County of York,
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:-
Although the lifting dogs or like appliances constructed according to my in-
vention are applicable to a variety of purposes, such as lifting, pulling and hauling,
they are more particularly applicable for use in lifting plates, such as boiler
plates, ship and armour plates and the like.
The ordinary methods employed for lifting such articles, say for example, a
boiler plate, is to employ a screw dog which is provided with jaws to receive the
plate, a screw passing through one of the jaws enabling the dog to be secured
to the plate by the tightening of the screw. The dog is also provided with a
ring or shackle by which it can be attached to a crane chain, or other lifting
tackle.
When suspended by such an appliance a plate is frequently subjected to jars
or vibrations either in the act of moving, or during the hammering whilst under
inspection, or by other process such as drilling, punching, rivetting or the like.

page_text: These jars or vibrations tend to so loosen the screw that the plate is liable to
slip from the jaws of the dog.
The object of my invention is to obviate this defect, and to provide a dog which,
instead of becoming loose when the article which it holds is subjected to jars,
vibrations or other strains, will grip the article more tightly and become more
securely fixed thereto by reason of such jars, vibrations or strains.
Figures 1 and 2 of the accompanying drawing represent in side views at right
angles to each other (Figure 1 being partly in section) a device constructed in
accordance with my invention.
Each jaw of the dog B, carries a screw stud A, the end which projects through
to inside the jaw instead of being convex or round ended, being made slightly
concave as shewn by the dotted lines at a so as to increase the frictional
resistance against the surface of the article to be lifted. The screws are preferably
right handed. The ends of the said screw studs which project to outside the
jaws of the lifting dog I form with portions or "cants" a² of hexagonal, octagonal
or polygonal shape, there being at the inward side of these "cants" a collar piece
or circular flange a' and at the outward side of the said "cants" a short length
of additional screw as shewn at a3.
For actuating the said studs and for suspending the dog, I pass onto the
hexagonal or like shaped part of each stud a link or lever handle C, one end c of
which fits, similarly to a close ended spanner, on to the said part of the stud,
the other end of each link being provided with an eye hook or ring to receive
a chain or other slinging tackle.
I preferably curve or bow both the links C, above the dog so that their eyes
or slinging ends are brought closer together when opposite to each other as
shewn in Figure 1. On the projecting screwed portion a³ of each stud I screw
a nut D, by which, what may be called the key end of the link, is secured to
the stud between the collar or circular flange a and the screw nut D) and pre-
vented from working off when in use. In place of using screwed ends and nuts for
this purpose I may use pins or cotters passed through the end a which may then
be plain. The action is as follows:-
Say for example a boiler plate is to be lifted. The screw studs A in the jaws
of the dog B, being wide enough apart to allow the edge of the plate to pass
between them, the link on one side of the dog would then be placed in a horizontal
or approximately horizontal position and the screw stud on the opposite side
will then be tightened by its link until a firm grip of the plate is obtained. If
in effecting this the link should happen to come in line with or to a corresponding
opposite angle to the first named link, the plate may then be slung from the
eye hook or ring end of the links when the weight of the plate would tend to
draw both links into a vertical position and thereby further tighten the hold
upon the plate of the studs in the jaws of the dog.
If the last named link did not come quite to the required position when screwed
up by hand, it would be taken from the stud and replaced in the required position.
The nut or other fastening by which the link is secured to the stud is readily
removed for this purpose. When plates of great weight have to be lifted, such
as armour plates, my improved lifting dogs may be made with longer jaws and
with four or more studs instead of two, each pair of studs acting in a similar
manner to that already described.
Figures 3 and 4 shew in side elevation and plan of underside such an arrange-
ment, the parts being marked with the same letters of reference as are used to
denote similar parts in Figures 1 and 2.
I do not limit myself to the precise means shewn for causing the strain exerted
in lifting to tighten the screws. I may for example use an arrangement such as
I have shewn in side elevation in Figure 5. The lever handles Care here each
replaced by a groove pulley or wheel C with chain attachments indicated by
the dotted lines so secured at one end to the wheel and passed partly therearound
that when a weight is being lifted by the dog the chains will act as levers on the

page_text: wheels and so tighten the grip of the screws upon the article. To loosen the
hold the pull on the chain would be reversed. This method would be very suitable
for hoisting or lowering plates vertically such as hot plates being put into oil
or other tanks for hardening or other purpose.
Having now particularly described and ascertained the nature of my invention
and in what manner the same is to be performed, I declare that what I claim is :--
1. In lifting dogs or like appliances a device connecting the dog with the
lifting or suspending tackle in such a manner that the lifting or suspending strain
tightens the grip of the dog on the article being lifted or suspended substantially
as herein before described.
2. The several arrangements of parts constituting lifting dogs or like appliances
substantially as herein before described and illustrated respectively in Figures 1
and 2 in Figures 3 and 4 and in Figure 5 of the accompanying drawings.
Dated this 31st day of July 1897.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C.