Safety means paying attention to the smallest details. A
hastily assembled workholding system can result in a hazardous operator
environment. Hydraulic workholding is not a generic technique where
most anything will work. Nor is there one right or best answer for
all situations. Each application is different and can be approached
in many different ways. Because of this versatility, there is no
rule-of-thumb to follow to guarantee safety. A careful balance of
knowledge, fixture design and common sense are key to avoiding injuries.
Plan your fixture installation with operator safety in mind.
By nature, most clamping devices have pinch points. Many times the
fixture can be designed to shield the operator from a pinching hazard.
Often the placement of
the clamping device in the fixture can minimize the gap between
the clamp and the workpiece, thus reducing or eliminating the pinch
point. Perhaps the clamping control valve or switch can be located
such that the operator cannot reach the fixture and the control
at the same time. Dual palm buttons on electrically-actuated systems
serve the same purpose.
Do not require the operator to hold the workpiece in position
during the clamping operation. Make sure that the workpiece is self-supporting
and self-locating so that operator hands are out of danger when
the hydraulic system is actuated. Often a simple spring plunger
is all that is necessary.
 The
lowest pressure ratingof any component in the clamping system
sets the maximum pressure rating for the entire system. Most hydraulic
workholding components are rated at 5,000 psi maximum. However,
some components are rated at less than 5,000 psi.The maximum pressure
is listed on each product page of this catalog. Never exceed
this rating.
 Just
having a clamp that is rated at 5,000 psi is not enough. Every hose,
fitting, valve, adapter and tube exposed to pressure must be rated
at or above the maximum hydraulic system pressure. Most “hardware
store” fittings are intended only for low pressure plumbing.
Never use water pipe fittings or copper tubing and brass fittings
for hydraulic service. |
 Use
proper tools when proper minimum bend radii for hoses and tubing.
If a hose or tube is ever kinked, replace it. Don’t risk a
rupture. Fluid escaping under high pressure is dangerous.The resulting
loss in pressure could release the workpiece from the fixture and
cause serious injury and equipment damage by being ejected from
the machine or breaking tooling.
Tubing and hoses do flex when pressurized.Allow for that movement
by supporting the fluid lines away from surfaces which could abrade
the surface
and eventually cause damage. Avoid straight lengths of hose and
tubing. A bend will allow for this deflection without putting too
much stress on the line.
 Even
if proper hydraulic tubing and fittings are specified, be sure to
protect them from abuse. Components damaged from abrasion or accidental
dropping of a workpiece will no longer have the strength
and safety of the original design.
Use proper mounting hardware when installing workholding
clamps and other components. Always use the largest bolt available
to fit in the mounting hole. In many cases, the recommended cap
screw
or thread is specified on the product page of this catalog. Sometimes
the mounting hardware is included with the component. Always use
supplied hardware. |
