An Improved Movement for Telescopic Tubes.
Year: 1895

page_text: Date of Application, 19th Sept., 1895
Complete Specification Left, 19th June, 1896-Accepted, 25th July, 1896
PROVISIONAL SPECIFICATION.
An Improved Movement for Telescopic Tubes.
I, ALFRED WRENCH, of 50, Gray's Inn Road, in the County of London,
Wholesale Optician, do hereby declare the nature of this invention to be as
follows:-
My invention has for its object to provide means whereby two or more tubes
telescoping one within another may be extended, or collapsed or withdrawn by
means of a single pinion, the said arrangement being applicable to magic lanterns
and to other optical and scientific instruments in which telescopic tubes are used.
A suitable arrangement for carrying out my invention is as follows-Each tube
of the series of tubes to be operated is provided with a rack which racks, when
the tubes are in their closed position, lie side by side but are so arranged that only
the rack of the outermost tube is in engagement with the pinion. When owing
to the rotation of the pinion the first tube has been extended to nearly its full
extent relatively with the succeeding tube I provide for locking the rack of this
first tube to the rack of the second tube so that the continued rotation of the
pinion moves the first tube until the rack of the second tube engages with the
pinion, the second tube being then extended in the same manner as the first tube
by the rotation of the pinion.
In practice I find it advantageous to employ a spring catch for locking the
racks together in the manner hereinbefore referred to, the said catch being
connected to one rack and having a tongue sliding in a groove in the adjacent rack
until it can enter a recess to form the lock.
In order to ensure that the innermost tube of the series shall always be extended
to its fullest extent before the second tube commences to move and so on provide
in connection with each tube except the innermost one, a lock which engages with
the next outermost tube and which is released by the inner tube when fully
extended.
It is to be understood that when more than two tubes are in the series that the
second and third, third and fourth, and so on, work in conjunction with each other
in a similar manner to that herein before described.
Dated the 19th day of September 1895.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
An Improved Movement for
1, ALFRED WRENCH, of 50, Gray's Inn Road, in the County of London,
Wholesale Optician, 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 has for its object to provide means whereby two or more tubes
telescoping one within another may be extended, or collapsed, or withdrawn by

page_text: means of a single pinion, the said arrangement being applicable to magic lanterns
and to other optical and scientific instruments in which telescopic tubes are used.
A suitable arrangement for carrying out my invention is as follows. Each tube
of the series of tubes to be operated is provided with a rack, which racks, when
the tubes are in their closed position, lie side by side but are so arranged that only
the rack of the front tube is in engagement with the pinion. When, owing to the
rotation of the pinion, the front or first tube has been extended to nearly its full
extent relatively with the succeeding tube 1 provide for locking the rack of this
first tube to the rack of the second tube so that the continued rotation of the
pinion moves the first tube until the rack of the second tube engages with the
pinion, the second tube being then extended in the same manner as the first tube
by the rotation of the pinion.
In practice I find advantageous to employ a spring-catch for locking the
racks together in the manner hereinbefore referred to, the said catch being
connected to one rack and having a tongue sliding in a groove in the adjacent rack
until it can enter a notch or recess to form the lock.
To enable my invention to be fully understood I will describe the same by
reference to the accompanying drawing, in which :-
:―
Figure 1 is a plan view of a series of telescoping tubes designed for use in a
magic lantern; and,
Figure 2 is a longitudinal section of the same:
Figures 3 and 4 are views illustrating a detail hereinafter described; and,
Figure 5 is a sectional view illustrating the operation.
a is the tube fixed upon the lantern front and b, c, d are three tubes telescoping
within the same.
e is the pinion by means of which the several tubes are operated,
the said pinion being carried on the tube a, and f, g, h are the racks on the
tubes b, c, d respectively, which racks are arranged relatively with one another in
the manner shewn in Figure 1, whereby when the tubes are closed together the
said racks will lie side by side, only the rack of the front tube d being in
engagement with the pinion e, the front portions of the other racks being cut away
as shewn at i, i, Figure 1.
With this arrangement it will be understood that the tubes being folded up or
closed together, the rotation of the pinion e will, as the said pinion is only in
engagement with the rack h, project the tube d. When the said tube d has
reached the limit of its outward movement relatively with the tube g, a spring-
catch which, during the outward movement of the tube d, has been sliding in a
groove k in the side of the rack g of the tube c, reaches the end of its movement
whereupon the continued rotation of the pinion by acting upon the rack h moves
out the tube c until such time as the teeth of the rack g of the said tube c come
into engagement with the pinion e.
The rack g is provided with a spring-catch similar to the catch j, the said
catch sliding in a groove m in the rack f whereby, when the said tube c has been
moved out to its full distance, the said catch 1 by pulling upon the rack f draws
the tube b outwards until such time as its rack f engages with the pinion.
The catches j and are carried upon spring-bars n, n which, when the tubes are
extended raise the said catches into notches n', n¹ formed in the ends of the
grooves in which the catches slide so that the tubes being once extended cannot
be again closed together until the said catches are moved out of the said
notches.
To provide for disengaging the said catches from their notches n', n, I form on
the free ends of the spring-bars n, n, teeth o, o corresponding with the teeth of
the racks and which normally project above the surface of the said racks as clearly
shewn in Figures 3 and 4 which are respectively a section on the line 3-3 of
Figure 2 and an elevation of part of the rack and catch . When, however, the
racks pass under the pinion e, the ends of the spring-bars carrying the teeth are
depressed to disengage the said catches. It will be understood that the position of
the teeth o, o upon the bars n, n relatively with the racks is such that the catches

page_text: are disengaged just at the moment that a tube reaches its innermost position, that
is first of all drawn within the
is to say, in withdrawing the tubes, the tube
tube a.
Just at the moment it reaches its innermost position, the teeth o in
connection with the catch run under the pinion e whereby the said catch is.
moved out of its notch n' so that the continued movement of the rack draws the
tube c within the tube b; when the tube c reaches its innermost position the
teeth o in connection with the catch jare beneath the pinion so that the further
movement causes the inward movement of the tube d.
In order to ensure that the innermost tube of the series shall be extended to its
fullest extent before the second tube commences to nove and so on, I provide in
connection with each tube, except the innermost one, a lock which engages with
the next outermost tube. The lock for each tube, as shewn in the drawings,..
consists of a pin p carried by a spring 7, the said pin being at one end adapted to
engage behind the flange p of the tube within which the tube having the lock
slides, the other end of the pin p being rounded as at r, which rounded end when
the tube sliding within the tube having the lock is moved out to its full extent
enters a depression or hole to allow the pin p to disengage from the flange pl..
This arrangement will be readily understood by reference to Figure 5 which
represents the position of the parts when only the tube d is extended. In this
position the locking pin p of the tube c has its rounded end in the recess r¹ in.
the tube d so that the said pin p is out of engagement with the tube b, whilst the
When the said tube c is
pin p of the tube b is in engagement with the tube a.
moved forward to its fullest extent, the head r of the lock on the tube b enters the
corresponding recess in the tube c so that the pin p disengages from the tube a
whereby the tube b can be extended.
It will be understood that on the inward movement of the tubes, the tube b.
first moves inwards and that as the tube c commences to move inwards it depresses
the pin p into engagement with the tube a, the same movement of the pin p of the
tube taking place as the tube d is moved inward.
Although I have only represented an arrangement of three extending tubes, it
is to be understood that a greater or less number may be employed.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The improved movement for telescopic tubes wherein the tubes are extended
and withdrawn by means of a single pinion, the said tubes being provided with
racks sliding side by side and so arranged that they are successively brought into.
engagement with the rack, substantially as described.
2. The combination with a series of telescopic tubes operated by means of a
single pinion, of catches connecting the racks together in such a manner that the
rack in engagement with the pinion at a certain point draws the succeeding rack
forward into engagement with the pinion, and that the tube cannot be improperly
moved inwards relatively with the other, substantially as described.
3. The combination with a series of telescopic tubes, of means for locking all:
the tubes with the exception of the foremost tube together to ensure that the
tubes shall be successively extended to their full extent, substantially as
described.
4. The manufacture and use of a series of tubes provided with means for-
extending and withdrawing them substantially as hereinbefore described and.
illustrated in the accompanying drawings.
Dated this 19th day of June 1896.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant..