Improvements in Machinery for Grinding Lawn Mower Cutters.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements in Machinery for Grinding Lawn Mower Cutters.
I, HENRY GIBBONS, of Kennet Iron Works, Hungerford, Berkshire, 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 improvements relate to a construction of machinery for grinding lawn mower
cutters for which I obtained Letters Patent No. 2387 of 1881, in which a grind-
stone is mounted on a shaft having a screw thread so that as it is made to revolve
with the grindstone it at the same time screws itself forward, and thus causes the
grindstone to travel along the lawn mower cutter as this also revolves.
My present invention consists in so arranging the gearing by which the combined
rotary and travelling motion is imparted to the grindstone that its direction of
motion as also that of the cutter is automatically reversed at the end of each travel,
instead of effecting such reversal by hand as heretofore.
I will proceed to describe the mechanism which I employ for this purpose with
reference to the accompanying drawings in which
Fig. 1 shews an elevation of so much of the machine as is necessary to describe
my invention, and Fig. 2 shews a corresponding plan.
B is the grindstone which is fixed on the shaft A formed with a screw thread
and working through a threaded bush in the bearing C so that as the shaft is
rotated in one direction or the other it at the same time travels longitudinally in one
direction or the other together with the grindstone so as to cause this to act upon
the cutter which is mounted in bearings on the slotted adjustable bed D.
The shaft A is driven by means of two fast pullies E E' and a loose pulley F.
The pulley E is fixed on a solid shaft G, while the pulley E¹ is fixed on a tubular
shaft G¹ through which the shaft G passes.
These shafts carry respectively bevil wheels H and H' which gear with opposite
sides of a bevil wheel I fixed on a shaft J that passes along the side of the machine
and carries at its other end a pitch wheel K geared by a pitch chain with a small
pitch wheel K' fitted with a feather and groove upon the shaft A so as to rotate
the latter while this slides to and fro through it.
The driving belt of the pullies E E' is shifted from the one to the other pulley
by a sliding fork L carried by the bracket M and connected by a link N to an
elbow lever O pivotted at O' to the framing and having the upper end of a rod O²
thereon geared to a sliding bar P sliding through the bracket immediately below
the bearing C.
The shaft carries a fixed collar Q at its end, and, at a distance from this corre-
sponding to rather more than the length of travel of the shaft and grindstone, it
carries a second fixed collar Q', such collars being adapted to come in contact
respectively with the one end of the sliding bar P and with the end of the
lever O.
From the above described construction it will be seen that, assuming the belt to
be on the pulley E, the shaft A and grindstone B will be driven through shaft G
wheels H and I, shaft J and pitch wheels K K' so as while rotating to advance in
the direction of the arrow Fig. 2, until the collar Q₁ comes in contact with the end
of the sliding bar P, when this, in being pushed outwards by the collar will cause
the lever O and fork L to reverse the position of the belt, bringing it upon the
pulley E. The shaft G¹ will now drive the shaft J through the bevil wheel H' in
the
contrary direction to its previous motion, so that the direction of rotation and
of travel of the shaft A and grindstone B will now be reversed, travelling in the
direction opposite that of the arrow until the collar Q comes in contact with the

page_text: end of the rod 02 of lever O and by shifting this back to its original position,
causes the belt to be again brought on the pulley E, and thus again reversing the
motion of the shaft A and grindstone G.
The other parts of the machine are the same as described in my said prior
Specification and need therefore not be farther described.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
In machinery for grinding lawn mower cutters, such as is herein referred to,
effecting the automatic reversal of the travel of grindstone B and its shaft A by
means of the driving gear E E¹ G G¹H H¹, I J, L NOQ Q' arranged and
operating as herein described with reference to the drawings.
A
01
1
1000
ABEL & IMRAY,
Agents for the Applicant.