s for raising
Year: 1897

page_text: Date of Application, 5th May, 1897
Complete Specification Left, 5th Feb., 1898-Accepted, 19th Mar., 1898
I, RICHARD THOMPSON, of Bagby, Thirsk, in the County of York, Blacksmith,
do hereby declare the nature of this invention to be as follows:-
My said invention relates to improvements in jacks for raising vehicles and other
light weights.
According to my invention I provide a rack bar sliding vertically within a
suitable frame. The upper part of the sliding rack bar is formed with the usual
crutch to support the vehicle or the like to be raised. Upon a fixed part of the
framing I pivot a lever which operates by means of side links a spring
detent engaging with the teeth of the rack bar. To operate the
jack the crutch carried by the rack bar is brought into position beneath
the carriage to be raised. The lever is then depressed and the spring
detent raises the rack bar and with it the vehicle or other weight.
Another spring detent sliding in the frame of the jack slips over the teeth of the
rack as the same is raised by the lever, and maintains the rack in its raised position.
On raising the lever the links are depressed carrying the spring detent downwards
over the teeth of the rack and the operation of raising the rack bar may be
repeated. A stop is provided on the rack bar to prevent it from being raised too
high. To release the spring detent and allow the rack to be lowered when required
I provide the frame with a fixed stop. By lowering the detent upon the fixed stop
the spring detent may be forced out of action with the teeth of the rack, when
upon the withdrawal of the secondary spring detent the rack bar may be allowed
to fall into its lowest position or may be arrested in any position by withdrawing
the spring detent from contact with the fixed stop.
To adapt the improved jack for raising weights disposed near the ground such
as for instance the fore wheels of a very low carriage I propose also to provide an
additional crutch carried from a bracket secured to the lower end of the sliding
rack bar. The lower crutch would then be capable of raising weights say from
about 4 inches to a height of 20 inches and the upper crutch from 20 inches to a
height of 36 inches, whilst both crutches would be operated by means of one lever.
The lower crutch might if desired be mounted upon a telescopic tube so as to
increase the height to which it could be raised.
Dated th
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page_text: I, RICHARD THOMPSON, of Bagby, Thirsk, in the County of York, Blacksmith,
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 and accompanying drawings:-
-
My said invention relates to improvements in jacks for raising vehicles and othér
light weights.
And in order that my invention may be fully understood I have attached hereto
a sheet of illustrative drawings to which I will refer.
Fig. 1 is a side elevation of my improved jack.
Fig. 2 is an end view of the same with the handle cut away.
Fig. 3 is a sectional plan through the line A B Fig. 1.
Figs. 4 to 7 are detail views on a larger scale.
In carrying my invention into effect I provide a rack bar a sliding vertically
within a suitable frame 6 formed with a steadying base b. The upper part of the
sliding rack bar a carries the usual crutch c to support the vehicle or other weight
to be raised. A handle or lever d pivoted at to the frame b is pivotally con-
nected to side links c. The side links e are adapted to operate a lifting pawl or
catch f. The pawl f is shown more clearly in the enlarged views Figs. 4 to 7.
Fig. 4 shows the lifting pawl engaging with the rack, Fig. 5 shows the pawl
disengaged.
Fig. is a plan view of the lifting pawl and
Fig. 7 is a view of the pawl at right angles to Fig. 4.
The lifting pawl consists of two halves embracing the rack bar a and loosely
pivoted together at f. Each of these halves is provided with a stud f, f engag
ing with holes formed in the lower ends of the side links c. The holes in the links e
are of such a size as to allow free play of the studs therein. A spring detent g
sliding in a bearing g¹ formed in the frame engages with the teeth of the rack
bar as clearly shown in Fig. 4.
The boss on the handle mounted on the spring detent g, and the bearing g'
are formed with cam surfaces. On turning up the handle the sliding detent g
is withdrawn against the action of the spring from engagement with the teeth of
the rack bar a as clearly shown in Fig. 5.
The action of my improved jack is as follows. The crutch c carried by the rack
bar a is brought into position beneath the carriage to be raised. The lever dis
then depressed, the links e being thus raised carrying with them the lifting pawl f.
This lifting action of the links turns the halves of the lifting pawl f upon their
pivots so that the pawl f engages with the rack.
This is clearly shown in Fig. 4. Thus by the downward action of the handled
the rack bar is raised. The spring detent g slips from tooth to tooth of the rack
bar a as it is being raised and serves to maintain the rack bar in its raised position.
The handle & may then be reversed if it is necessary to raise the carriage higher.
On lifting the lever d the links e are depressed and thus turn the halves of the
lifting pawlf on their pivots and withdraw the pawl from the rack tooth as shown
in Fig. 5. The lifting pawl f slides down over the rack teeth until the lever dis
again reversed when it immediately engages with a tooth of the rack bar a.
When it is desired to return the rack bar a to its lowest position the handle g³
of the spring detent g is turned up thus withdrawing the detent g from the engage-
ment with the rack. The handle d is then raised until the descending pawl e
comes into contact with a fixed stop ŉ formed on the cross stay h¹ of the frame.

page_text: The pawle is thus turned on its pivot so as to disengage it from the rack as
shown in Fig. 5. The rack bar then descends by gravity to its lowest position.
To adapt the improved jack for raising weights disposed near the ground such
as for instance the fore wheels of a very low carriage I also provide an additional
crutch & carried from a bracket j secured to the lower end of the sliding rack bar.
The lower crutch i is thus capable of raising weights say from about 4 inches to a
height of 20 inches and the upper crutch from 20 inches to a height of 36 inches,
whilst both crutches are operated by means of one lever. The lower crutch is
mounted upon a telescopic tube so as to increase the height to which it can be
raised.
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. The improved jack for raising vehicles and the like constructed arranged and
acting in the manner and substantially as described and illustrated.
2. As means for raising and lowering a rack bar in carriage jacks of the
indicated nature the pivoted lifting pawl f operated by links e actuated by the
handle d working in conjunction with the fixed stop h in the manner and sub-
stantially as described and shown.
3. In carriage jacks of the indicated nature the pivoted lifting pawl of actuated
to raise and release a sliding rack bar substantially as described and shown.
Dated this 2nd dar of Fobruo 1808
Dated this 2nd day of February 1808
For the Applicant,
E. K. DUTTON & Co.,
Chartered Patent Agents, 5, John Dalton Street, Manchester.