Plate 39Larger plate.
Larger plate.
650. Screwed end and nut,the hole in wheel being square, or round and fitted with key.
651. Gib head taper key.
652. Plain taper key.
653. Taper round pin.
654,655. Split pins(round).
656. Cotter and split pin.
657. Cotter and nut.
658. Dovetail taper key,or fixing for projection, cutter or bracket.
659. Self-locking pin;cannot work out.
660. Split collar and ring fastening,sometimes used instead of a nut and screwed end; the inner ring is in halves.
661. Piston rod fastening.
662. Locking feather and wedgefastening, for rollers, &c., prevents end motion.
663. Railway chair key.
Various forms of friction gearing are much used, the chief objection to this kind of gear being the excess of pressure on the bearings required to give sufficient grip to drive the gear.
664. The common form of flat-faced friction gearfor hoisting purposes, &c. SeeNo. 1211. The required pressure is given by a weighted lever.
665. Friction bevils,plain faces, for governor driving, &c.
666. Friction bevils,the pinion being usually of hard leather; the pressure may be applied in the direction of either of the arrows.
667. MultipleVgear.A common mistake is to run these too deep in gear; the narrower the surfaces in contact, short of the seizing or crushing point, the less the power wasted in friction.
668. A very small pinion of leather, wood, or rubberis frequently driven by a large driving wheel for obtaining high speed with steadiness, for driving dynamos, fans, &c.
669. Disc wheel and rubber pinion,arranged to reverse motion or vary speed. SeeNo. 1595. The motion is reversed by throwing either wheel into gear with the pinion, and the speed varied at will by raising or lowering the pinion, used for screw presses.
670. Wedge friction gear.
Plate 40Larger plate.
Larger plate.
671. Coupled bearingsfor friction gear, to allow of any required pressure or “bite,” the strains being self-contained.
See alsoNo. 737,738,1294.
672. Two bars and crosshead;these must be far enough apart to allow for the angle of the connecting rod.
673. Four bars, crosshead, and slide blocks;the connecting rod working between the two pairs of guides. The bottom guides are often cast solid with the bedplate.
674. Bar and slipper.
675. Adjustable slipper;there are other adjustments for wear by wedge pieces, similar toNo. 19. See alsoNo. 21.
A plain guide bush is sometimes used asNo. 682, and a forked connecting rod with long fork coupled to the gudgeon or crosshead.
676. Section ofNo. 673and alternative crossheadfor two round bar guides.
677. Slide bed and slipper.
678. Section of trunk guide,cast with engine bed and bored out.
679. Oscillating cylinder piston head guides.
680. Oscillating fulcrumin lieu of guides.
681. Diagonal crosshead and guide bars,to allow the crank and connecting rod end to pass the guide bars.
682,683,684, &685.
686&687. Guide rollersfor ropes, &c.
688&689. Guide rollersfor bars of various sections.
690. Cage guided by four corner posts.
691&692. Cage runs on two vertical rails,and is steadied by a third guide. For large cages. Small cages only require guides on one side, as692.
Plate 41Larger plate.
Larger plate.
693. Iron wire or rod guides,strained tight, are sometimes used, especially in mines, as guides for the cage; two are used to guide the cage and two for the balance weight.
694. Planished round iron guides,with half round fixing brackets and runners attached to cage; these guides are equal to planed bars and much less costly; two are usually sufficient for any cage.
695.TLor⊔iron guides,for goods lifts.
696. Wire rope guides,with separate pair of wood guides for balance weight.
697. Intermediate guidesfor double cage lifts; for large cages extra guides at each side should be used.
698. Sloping carriage guides.
699. Vertical bracket cage guides.
700. DoubleVbed,with set screw adjustments.
701. Guide bedfor planing machine, or any machine where the bed is not liable to lift in working.
702. Round bar and flat guide bed.
703. DeepVguide;much used for crossheads, tool boxes, &c., requiring accurate movement.
704. Lathe bedwith square guides and adjustments for wear.
705. Planing machine,doubleVbed.
706. Crossheadfor two single bar guides, with renewable wearing strips and square guide surfaces.
707. Radial slidefor tool box, usually of same section asNo. 700.
708,709, &710; in709the rope can be threaded without passing the end through.
711. Conical rotatory gear.Applied to reaping machines. See also Pan Screen,No. 1264.
712. Triangular eccentric,used to obtain a pause of one-third revolution at each end of the stroke.
713. Face plate worm gear.
714. Double rack and pinion gear.
715. Double gear wheels.
Plate 42Larger plate.
Larger plate.
716. Eccentric gearing;the wheelAbeing fixed on a crank pin in the driving wheelB, drives the dotted gear at a speed proportionate to the diameters of the wheelsAand the driven wheel.
717&718. Forms of epicyclic or planet gear.Several modes of driving these may be employed by fixing one or other of the three wheels, the other two revolving. See Differential Gear,Section 31.
719. Multiple trammel gear.The pinion is half the diameter of the wheel, and makes two revolutions to one of the wheel.
720. Trammel crank gear;the crank revolves once to two double strokes of the rod.
721. Knight’s noiseless gearing,for two shafts running in opposite directions. Each shaft has two equal cranks at right angles, which are coupled by links to rocking arms, which are also coupled in pairs.
722. Eccentric variable speed toothed gear.
723. Scroll bevil gear.
724. Segment reversing gear,to obtain two speeds in portions of one revolution, and in opposite directions. See Reversing Gear,Section 74.
725. Snail wheel,or scroll ratchet.
726. Combined spur and bevil wheel.
727. Double screw gear,for steering gear, &c.
728. Angular ball-jointed crank motion.
729. Crank gearingbetween two shafts running in the same direction. SeeNo. 187. The cranks should be similar toNos. 174or175.
730. Snail worm gear.
731. Diagonal engine or pump,with bevil gear revolving motion and three or more cylinders.
732. Angle couplingon Dr. Hooke’s principle. SeeNo. 292.
733. Worm and crown gear.Used in chaff machines; useful to obtain a slow feed on two shafts in opposite directions.
Plate 43Larger plate.
Larger plate.
734. Ball wheel,with limited angular traverse gearing into one or two pinions.
735. Scroll and rack.
736. Variable speed gear,from an elliptical or other irregular-shaped driving wheel, combined with a tied idle intermediate wheel.
737. Spring friction grip wheels.
738. Intermittent reversible feed motion.The pinion is of leather, and drives the segment till it runs out of gear; when the machine is reversed it travels an equal distance the opposite way.
739. Is a device for varying the opening of a main valve(connected to rodA) by the pressure on the small piston, which moves it against the tension of a spring.
740,741,742, &743. Types of centrifugal governors,of which numerous varieties are in use.
Pumping enginesmay be governed by allowing the pressure of water in the rising main to accumulate in a stand pipe or equivalent device until it stops the engine by excess of pressure. To prevent such an engine running away a catch is used, kept open by the pressure of water; when the pressure falls below a certain point the catch is released and closes the throttle valve.
Steam enginesmay also be safeguarded in the same way by a catch which is released and closes the throttle valve when the governor becomes fully expanded.
744. Screw and nut device,to control the travel of any machine, such as a lift, by reversing the belt or throwing out a catch after any specified number of revolutions, the travel being adjusted by the stop nuts.
745. The cataractis one of the oldest governing devices. It consists essentially of a vessel which is filled with water by one stroke of the engine, and empties itself through an adjustable orifice during the return stroke, the valve motion being prevented from reversing till the water is all discharged.
746. Gas engine governor.RodAhas a reciprocating motion from the engine, and the spur on leverBstrikes the end of the gas valve slide when brought in line with it by the motion of the governor, thus supplying gas only when the governor falls to a certain point.
Differential Governor. SeeNos. 556and557.
747. Is the ordinary “chain and sheave” multiplying gear,unequally geared,thus—
748. Is the same plan,but equallygeared—
749. An arrangement of the sheavessuitable for vertical working, geared 8 to 1.
750. An arrangement of the sheavessuitable for vertical working, but geared 6 to 1.
Plate 44Larger plate.
Larger plate.
751. An arrangement of the sheavessuitable for vertical working, but geared 4 to 1.
752. Stevens and Major’s patentfor horizontal working. The angle of the chain helps to support the weight of the ram.
753. Modification of752,sometimes used, and suitable for both horizontal and vertical positions, with any required multiplication of speed.
754. Rack gear;short stroke piston cylinder plan.
755. Double rope vertical ram gear.
756. Arrangement with the sheavesall at head of cylinder.
For Telescopic Hydraulic Lift, seeNos. 1217&616.
Hydraulic Balance gear,Nos. 371,373.
For Chains and Links, seeSection 11.
757. Double or match hook.
758. Split link.See also the common Key Ring.
759. Self-locking hook,with inclined shoulder and pin.
760. The common “Lewis.”
761. Self-gripping claw grab.See also516,505.
762. Grab bucket,on same principle.
763,764, &765. DoubleSlinks.
766. Hook with rope grip.
767. Snap hook.
768. Snap link.
769. Slip hookfor a monkey or pile engine; a rope is attached to the eye in end of lever which pulls the loop link away from the bottom link to which the “monkey” is suspended, allowing it to fall.
Plate 45Larger plate.
Larger plate.
770. Automatic slip hook;slips theTend of the “monkey” by the curved arms striking the sides of a fixed stop hole.
771. Draw bar hook,self-locking.
772. Fixed bar hook,with snap.
773. Slip hook.
774. Hook,with mousing ring; slip hook.
775. Crane hook,with swivel.
776. Double swivel links,inserted in a chain to take out the twist.
777. Triangular link,to attach two chains to one.
778. Safety link.Has a flat on link to slip in notch of hook.
779.Slink.
780. Split link.
781. Bolt shackle.
782. Double link and bolt connectionfor ordinary chain.
783. Pin shackle.
784&785. Hand (portable) indicator,to indicate speed of revolution of a shaft, &c., by simple wheel work and dial plate.
786. Governor gauge,indicates the speed by the angle of the balls moving a finger on a vertical scale.
787. Steam engine indicator,of which there are many varieties. Macnaught’s, Richards’, Darke’s, Kraft’s, Casartelli’s, &c., are examples, in which a small steam piston operates a marking point by the varying pressure of steam acting against a spring; the paper is usually coiled on a cylinder having a reciprocating motion by a string from the engine.
788. Morin’s dynamometer.Consists of two belt pulleys connected by a spring; one receives the strain of driving belt, and the other transmits it, the spring indicating the tension on the belts.
789. Regnier’s dynamometerindicates the tension on the connections by contraction of the spring operating a dial plate.
790. Bourdon tube pressure indicator.The tube is of flat section, and its curved portion expands with the pressure, operating a finger on the dial by rackwork.
791. Worm gear and dialto register the number of revolutions. SeeNo. 1559.
Other forms of pressure gauges are—1st. The mercurial gauge, in which the pressure is indicated by the height of a column of mercury in a glass tube. 2nd. The water gauge, in which a column of water replaces the mercury. 3rd. The spring balance (seeNo. 1729). See alsoNos. 1730,1728.