Wednesday, July 29, 2009

GN 665 Series Arched Pull Handles

Diane here with another new product to introduce to you from our line of standard machine components. Today we're showing off our GN 665 Series Arched Pull Handles.

Available in metric sizes, the tapped-type handles are produced from elliptical aluminum extrusions and have a black powder coated textured finish. The end pieces are made of zinc die-cast with a silver powder coated textured finish. The mounting screws, hexagon nuts, and washers are zinc-plated.

These handles are notable for their elegant design and are RoHS compliant.

Thursday, July 23, 2009

Characteristics of Common Plastics Used in Machine Components

Diane posting, here to talk about—or rather scratch the surface of—plastic. In the nearly 150 years since plastic materials were conceived, these man-made materials have evolved into countless types for every possible use. Today I’ll just touch on a few categories of plastic that are frequently used in industrial parts.

Nylon is a technopolymer, and is typically referred to as polyamide (PA). Nylon was the first commercially successful synthetic polymer. The wide variety of different modifications that can be made to technopolymer allows it to be produced with different mechanical properties, chemical resistance, temperature resistance and colors, even crystal-clear. Nylon can be used as the matrix material in composite materials, with reinforcing fibers like glass or carbon fiber, and which then have a higher density than pure nylon. Such thermoplastic composites (25% glass fiber) are frequently used in components where their good heat resistance—up to 150°C (300°F)—making them practical competitors with metals. Glass fiber reinforced nylon is used in the production of J.W. Winco’s WN 300 Nylon Plastic Adjustable Levers, shown here.

Polypropylene (PP) is a thermoplastic polymer that is rugged as well as unusually resistant to many chemical solvents, bases and acids. It is resistant to fatigue and tolerates high heat—66°C (150°F). It can be extruded or molded. Many physical finishing techniques can also be used on polypropylene, such as machining. Surface treatments can be applied to PP parts in order to encourage adhesion of inks and paints. Fiberglass reinforced polypropylene is used for our MFE Cabinet U-Handles.

Elastomers/thermoplastic elastomers are polymers with the property of elasticity. The term, which is derived from elastic polymer, is often used interchangeably with the term rubber. Components of these materials can be stretched and bent without exerting great force. Once the deforming force relaxes or no longer acts at all, the parts take their original shape. At ambient temperatures rubbers are relatively soft and deformable. Their primary uses are for seals, adhesives and molded flexible parts such as wheels. Elastomers can be made in varying degrees of hardness and can be dyed easily. Elastomer is also often used for non-skid pads like those on the bases of our SNSM Snap-Lock Non-Skid Leveling Mounts.

Thermoplastic elastomers (TPE), sometimes referred to as thermoplastic rubbers, are a class of copolymers or a physical mix of polymers (usually a plastic and a rubber) which consist of materials with both thermoplastic and elastomeric properties. TPE is used as an outer coating on our EN 5337.6 Softline Star Knobs, to provide a soft, ergonomic grip.

Duroplast is a resin plastic reinforced with fibers (either cotton or wool) making it a fiber-reinforced plastic similar to glass-reinforced plastic. It is light, flexible and strong, but has low elasticity. Phenolic resins are among the most commonly used Duroplast materials. Unlike technopolymer, Duroplast and phenolic plastics cannot be melted because they remain rigid up to degradation temperature. The coloring and dyeing options of components made of Duroplast are limited. Duroplast is used in our EN 940 Three Spoked Handwheels to make them strong and durable.

Like I said, that just scratches the surface of plastics and all there is to know about their use in industrial components. You can find some additional technical information about plastics in our Web site’s Technical Section, including General Heat Resistance for Plastic, Material Characteristics Chart of Duroplast and Technopolymer Plastics, and
Material Properties Chart of Elastomers (Rubber).

Wednesday, July 15, 2009

GN 316 Interchangeable Insert Ratchet Wrenches

Diane reporting, with another new product from our line: series GN 316 Interchangeable Insert Ratchet Wrenches with Reversing Lever. Made of steel and available in metric sizes, these RoHS-compliant Ratchet Wrenches are ideal for assembly and repair work, as well as fixed applications on machinery and equipment. The housing of the wrench is coated with black matte plastic in a textured finish. The knob is made of glass fiber-reinforced polyamide technopolymer.

In order to reverse the operation of this wrench, you simply move the cam lever from its middle position either to the left or to the right to obtain the function required. In the middle position the ratchet function is eliminated and the spanner can be used in both directions as an ordinary wrench.

These wrenches are available in tapped insert type, round bore with keyway, and square bore type. The inserts are easily interchangeable--to exchange the inserts remove screw and cover--and can be supplied individually upon request. For certain minimum quantities, hexagon and modified inserts with inch size threads, round bores with keyway, and square holes are available. Other handle lengths are offered upon request.

Monday, July 13, 2009

Choosing Spring Loaded Devices for Positioning and Locking

Diane here, to talk to you today about the engineer’s options when he/she needs to align, hold, or latch different parts of equipment together. When this is your objective, you need a spring loaded device, and the options for that component are many and varied.

Breaking it down most simply, these sorts of devices consist of a body, an internal spring, and a ball or nose. They may also have a knob, button, or lever for the operator to control by hand. The general purpose of these components is to use the force in the spring to apply pressure so that the ball or nose will remain nested in some sort of hole or other receptacle. This way two or more elements of the equipment can be aligned or fixed into a determined relative position.

There are countless uses for positioning and locking components. They are used in workholding applications, as well as for indexing, latching, ejecting, and even electrical contacts.

So let’s examine the various types of components in this category (featured in our Section 10, Indexing, Spring and Ball Plungers).

Indexing plungers: These have a beveled or rounded nose that inserts easily into an indexing receptacle. The nose is long enough to fix the position firmly, preventing movement in any direction. In order to move the position of the plunger, the operator must mechanically retract the nose. An example is this GN 617 indexing plunger (non-lock out type).

Spring plungers: Spring plungers differ from indexing plungers in that they have a nose designed to allow for movement when some side force is applied. In other words, it isn’t necessary (or possible) to retract the nose mechanically. Consequently, these plungers are not appropriate if heavy side load is involved in the application. Shown is our SPNL short spring plunger (note the nylon locking element in the side of the threaded body).

Hand-retractable spring plungers: These plungers are sort of a hybrid of the two above types, and include a knob for manual retraction of the plunger. Among other things, they are used for manual or automated holding, as in workholding applications. Here you see our LRSS stainless steel hand retractable spring plunger (lock out type).

Ball plungers: These have a ball instead of a nose, and no knob. The shallow depth of the ball allows for easy movement in and out of position, but as with spring plungers, they do not perform well with heavy loads. The illustration is our GN 615 steel ball plunger with threaded body (note the slot provided for installation with a screwdriver).

Side thrust pins: These components are designed for fixturing small parts and holding them in place with constant pressure, as shown in the illustration. In the photo you see the GN 713 zinc-plated steel side thrust pin, which has a threaded body.

Quick release pins: Instead of body with a nose, these components consist of a rod or stem, from which small side securing pins protrude. A button in the handle retracts or extends these pins so that the quick release pin can be removed or secured in place (see application example).

The component in the illustration is our GN 114.2 steel rapid release pin. We offer many other options for quick release pins, including stainless steel components, heavy duty construction, and self-locking features.

So far this seems fairly simple, right? Spring-loaded components aren’t rocket science (especially if yours truly can explain them). We offer these types of components in many sizes, both inch and metric. But there are more options than that to consider. Let’s start with balls and noses.

Balls and noses: Balls, as mentioned above, allow for easy position changes. However, their holding force is limited. Noses may be round for reduced friction and similar easy positioning. They can also be chamfered for easier insertion into indexing holes. Flat noses have a larger contact area but will obviously resist side motion. Hex noses can allow installation of the plunger from the front with a hex wrench, but are subject to faster wear.

The material chosen for the ball or nose is also key: case hardened steel noses are strong and heat-resistant, but can mar the surface to which they press. Delrin® is a very strong plastic that holds up well, is self-lubricating, and will not mar. Nylon also resists marring and corrosion but doesn’t wear as well and can’t be used in temperatures above 82ºC (180ºF). Phenolic plastic is an economical option but is more brittle. Stainless steel is the best choice for sterile applications.

Body attributes: The body of a plunger varies depending upon installation considerations. It may be threaded, it may have a lock nut for securing the mounting (see illustration). Or it might be smooth for push-fit installation, or smooth and weldable. Threaded body plungers may have a locking element or patch. There may be a hex or slot on the end to assist in mounting.

The same material issues apply to the body as to the nose or ball. Case-hardened steel stands up to high forces. Steel may be zinc-plated or have a black oxide finish. Stainless steel tolerates high forces, heat, and corrosion. Brass is another option for metal plungers. As for plastic, a Delrin® body is non-magnetic and resists corrosion but will not tolerate heat.

Space considerations may require you use a short or stubby plunger. An extra-long plunger (“long-travel”) or long nose can be used to meet side force holding requirements or for holding up metal sheets. This latter is illustrated by our GN 611 long stroke spring plungers.

Springs: Springs are generally made of steel or stainless steel, and their end force determines the applications for which the plunger is appropriate. For detents, you will need a heavy or standard end force. If you want an easily retractable plunger, use standard or light end force. Heavy end forces permit the plunger to hold its position by end force alone. Light end forces prevent marring. Many of our plungers are available in all three versions.

Hand-operating elements: For hand-retractable plungers, the plunger incorporates an element that the hand can hold, pull, or manipulate. Options include knobs with or without knurling, L-handles, T-handles, and pull rings. Some plungers have a threaded end that will accept whatever knob or handle the user wishes to install. There is also the cam-action indexing plunger, which is designed so the turning of a handle in a circular direction causes the nose to retract.

J.W. Winco offers the unique type of cam-action indexing plunger pictured here, which permits the plunger pin to be held in either a retracted or protruding position. View GN 712 and GN 712.1 for full details.

Lock out or non-lock out: Last, but not least, is the issue of whether or not the plunger needs the option of holding a retracted position. Lock out type plungers are designed so the operator can pull the plunger into a retracted position, perform a turn of the knob or handle, and let go, and the plunger nose will stay retracted. Cam-action plungers may be either version.

Receptacles for plungers: Obviously the ball, nose, or pin of a plunger or release pin needs a receptacle. The receiving element need be no more complicated than a drilled hole or indentation. It may also be a flange or a mounting block that is mounted by welding or screws to a surface. See the illustration for an example using a mounting block, our GN 412.2.

Accessories: Spacer bushings are a useful component of plunger applications, and compensate for the body thread lengths on indexing plungers to allow mounting through walls of varying thicknesses. Ball chains and lanyards can be used as ways to “tie” removable plungers and release pins to a piece of equipment so they will not be lost, as you see in the illustration (our GN 113.3 rapid release pins with a ball chain).

Well, as far as these varied and useful positioning and locking components, that’s all I got. But if you want to know even more, visit Section 10 of our online catalog, or contact one of our Technical Sales associates!

Thursday, July 9, 2009

New Fasteners in our eStore

It's Diane, and as promised, I'm letting you know about the first two series of metric fasteners now available with full details on our Web site and in our estore.

The first is our DIN 439B Hex Jam Nuts. These nuts are available in steel or zinc-plated steel, material property class 8. The A2 type is offered in stainless steel, property class 304. The nuts are fully threaded. They also conform to ISO 4035/ISO 8675 and ANSI B 18.2.4.5M and are RoHS compliant.

Secondly, we now offer DIN 934 hex nuts. These nuts are also available in steel or zinc-plated steel, material property class 8. Again, the A2 type is offered in stainless steel, property class 304. The nuts are fully threaded. They also conform to ISO 4032 and ANSI B 18.2.4.1M and are RoHS compliant.

J.W. Winco has a broad array of other fasteners available upon request. You can see an overview on our DIN metric fasteners page.