US3540500A - Guard assembly for chain saws - Google Patents

Description

United States Patent Inventor Gordon C. Greene 1550 S. 15th Place, Redmond, Oregon 97756 Appl. No. 767,423

Filed Oct. 14, 1968 Patented Nov. 17, 1970 GUARD ASSEMBLY FOR CHAIN SAWS 8 Claims, 4 Drawing Figs.

' 143/159 Int. Cl. B27b 17/02 Field of Search 143/32:

[56] References Cited UNITED STATES PATENTS 2,709,464 5/1955 143/159X 2,937,673 5/1960 143/32 3,182,695 5/1965 143/32 3,414,026 12/1968 143/32 Primary ExaminerDonald R. Schran AttorneyBacon and Thomas ABSTRACT: A guard assembly for mounting on the lateral edge of the bar of a chain saw, comprising a pair of uniquely shaped elongated sheet metal members that are bolted to the bar and which define an outwardly opening channel within which the cutting chain of the saw is received. The guard assembly is designed to be nonclogging, and can be removed when necessary to utilize the full length of the saw bar.

GUARD ASSEMBLY FOR CHAIN SAWS BACKGROUND OF THE INVENTION bar type are in common use today, and numerous attempts have been made to provide guards therefor. Usually, such guards involve complicatedmovable shield arrangements that are subject to failure, and which can block the operator's view of the cutting operation. in addition, it is not uncommon for the clearance between the cutting chain and the guard to become clogged with sawdust and wood chips.

There'is need for a simple, stationary guard arrangement that will effectively guard the cutting chain, and which is designed to prevent clogging. The present invention satisfies that need.

SUMMARY OF THE INVENTION The present invention is especially designed for use with a chain saw when only the forward, rounded'cnd of the saw bar is required to perform cutting operations. This condition is "present when an operator is engaged in tree-thinning, knotbumping. brush-clearing. pole-cutting, tree-topping, firewoodcutting, and many other operations, in all of which only a portion of the saw chain is really necessary to the task. The guard assembly of the invention is bolted to the saw bar, does not interfere with the use of the saw for cutting operations like those mentioned, and can be easily removed for those few cutting operations where the full length of the bar is required.

. 'Both lateral edges of the saw bar are usually fitted with a guard assembly, the guard assembly on the upper lateral edge being shorter than that on the lower edge and terminating a distance rearwardly of the rounded saw bar tip to expose a straight portion of the saw chain or blade; The unique channel construction of the assemblies render them sufficiently strong to allow considerable force to be placed thereon before damage can occur, and the assemblies also serve to protect the saw chain during transport and eliminate the need for the special covers sometimes provided for this purpose.

it is the principal object of the present invention to provide an effective guard assembly with no moving parts that can be easily mounted on the lateral edge of the bar of a chain saw, and which is nonclogging in operation.

Another object is toprovide a chain guard saw assembly that is useful to guard the saw chain both when such is in operation, and when the chain saw is in transport.

Other objects and many of the attendant advantages of the present invention will become readily apparent from the following description of the preferred embodiment, when taken in conjunctionwith the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. I is a side elevational view of a chain saw, showing a guard assembly mounted on the upper and lower lateral edgesof the-saw bar;

FIG. 2' is an enlarged sectional view taken on the line 2-2 in FIG. 1, showing in'detail the configuration ofthe guard assemblies;

FIG. 3 is a view depicting how the lower guard assembly of the invention operates to shield the leg of an operntonand chain saw is indicated at 2, and includes a motor housing 4 FIG. 4 is a view depicting how the, upper guardassembly enables an operator to grasp the saw bar with safetyf DESCRIPTlQN OF THE PREFERRED EMBODIMENT- Referring now to the drawings, a conventional haiid-held having a handle 5 and to which asaw bar 6-,is, attached, thc saw 6 comprising aplate having a rounded nose-portion 8, and

upper and lower lateral edge portionsllland 12, respectively,

that taper toward each other moving rearwardly from-the nose, portion 8. The center portion of the saw bar 6 has a cutout l4 therein, and riding in a track 16 cut into the edges of the plate portions 8, l0 and 12 are the anchor plates l8 of asnwchain 20 that is connected within the housing 4 to be drivenby the saw motor (not shown). The components just described, with variations in design and configuration, are generally found in all chain saws'ol' the type with which the guard assembly-of the invention is intended for use.

Mounted on the saw bar lateral portions [0 and 12 are upper and lower guard assemblies 22 and 24, respectively. The upper guard assembly 22 comprises two guard'mcmhcrs 26 and 28, which are made of sheet metal and include flat attachment flange portions 30 and 32, respectively, that are secured to the opposite faces of the upper saw bar lateralportion 10 by spaced bolts 34. One of the bolts'34 is disposed at euchend ofthe guard assembly 22, and in addition preferably at least one bolt 34 is installed between said=ends. The saw" bar 6, if it does not already have holes therein to receive the bolts 34, is drilled appropriately so that the inner cnd' of'tbe guard assembly 22 is located adjacent to the motor housing 4'.

The upper edges of the attachment flange portions 30 and 32 are spaced a substantial distance below the upper edge of the saw bar 6. Extending upwardly and outwardly from the upper edges of the attachment flanges 30 and, 32 at about a 30 angle to the vertical are integral spacer strip portions 36 and 38, respectively,- the upper edges thereof terminating about midway the height of the saw chain 20. Extending vertically from the spacer strip portions 36 and 38 are integral, generally parallel shield flange portions 40 and 42', respectively, the upper edges 44 and 46 of which are reinforced by outwardly and downwardly bent integral reinforcing flanges 48 and 50, respectively. The upper edges 44 and 46 of the shield flange portions are spaced a substantial distance above the saw chain 20 and the forward ends 52 and 5,4 of the guard members 26 and 28, respectively, are tapered rearwardly from the exposed saw chain-20 at about 55 angle to the horizontal, whereby to give proper cutting exposure to the saw chain 20.

The dimensions for the guard assembly 26' can of course be varied, but typically the attachment flange portions 30 and 32 will be about three-fourths inch in height, the strip- portions 36 and 38 about l'ive-eighths inch, and the shield flange portions 40 and 42 about three-fourths inch. The channel formed by the shield flange portions 40 and 42 should be about three times wider than the width of the saw chainv 20, whereby to alleviate clogging, the moving chain 20 functioning to discharge chips and other debris from the open channel.

It should'be noted that the uppercdges of the attachment flanges 30 and Marc spaced below the uppercdge of the saw bar 6, whereby the inclined spacer'strips 36-and38 are spaced laterally a substantial distance from the juncture of the saw chain 20 and the saw bar 6. This arrangement helps ensure against debris becoming wcdgedbetween the saw chain 20 and the saw bar 6. and thus contributes to the nonclogging feature ot'the invention.

The lower guard 24 is constructed similarly to the guard 22, and includes two members 56 and 58 comprising attachment flange portions 60 and62, spacer strip portions 64" and 66,

parallel shield flange portions 68 and 70, and reinforcement Also attached to the saw bar 6 by bolts 76 is a dog orfinger 78, commonly utilized on chain saws to help start the saw chain 20 into the work to be sawed. The forward end of the guard assembly '24 is attached to the saw bar 6 with the same bolts 76 normally used to mount the dog 78, the inner front corners 80 and 82, respectively, of the guard members 56 and 58 being cut back at an angle to fit the rear portion of the dog. Except for the corners 80 and 82, the front and rear edges of the guard members 56 and 58 lie perpendicular to the bottom edges of their respective members.

The bottom guard assembly 24 is longer than the top guard assembly 22. and extends from the motor housing 4 to the dog 78. While only the rounded tip 8 of the saw bar 6 and a small portion of the upper" lateral edge portion 10 are unguarded, this presents more than sufficient exposed saw chain to accomplish normal brush clearing and cutting, and even the cutting down oftrees of up to several inches in diameter.

The guard assemblies 22 and 24 effectively shield the ,saw

' chain 20 along the lateral edge portions 10 and 12 of the saw bar 6, as shown in FIGS. 3 and 4. in H0. 3 the hand-held saw 2 has slipped and engaged the leg L of the operator 0, which said saw chain and extends outwardly from the suwbarn substantial distance beyond the cutting edge of the saw chain,

2. A guard assembly as recited in claim L whc'rcin each of said members includes an attachment flange portion citgagcuble with said saw bar, and including a plurality of bolts for securing said attachment flange portions to said saw bar.

3. A guard assembly as recited in claim 2, wherein each of said members includes a spacer strip portion extending between said attachment flange portion and said shield flange portion, said spacer strip portion being inclined outwardly at an angle of about from the plane of said attachment flange portion, and said attachment flange portion and said shield flange portion lying in parallel planes.

4. A guard assembly as recited in claim 3, wherein said shield flange portions have reinforcement flanges formed on normally could cause a most severe wound. However, in FIG.

3 the guard assembly 24 keeps the saw chain 20 out of contact with the leg L.

In Fl G.'4 the operator 0 has gripped the guard assembly 22 withhis hand H to helpguide and balance the chain saw 2 during cutting; This would be impossible without the guard assembly 22.

The present guard assembly is ideally suited for use with chain saws having automatic oilers, and also functions as a guide and shield to prevent the guarded portion of saw chain 20 from coming into contact with limbs or brush, which might knock it from the track 16. With the guards 22 and 24 in place the operator 0 can also use the saw bar 6 to scoop or move aside brush and limbs, without damage to the saw chain 20.

The guard assemblies 22 and 24 are relatively strong, in part because of the 30 acute angle of the spacer strips relative to the attachment and shield flange portions. This relatively small acute angle gives the necessary spacing of the shield flanges from the saw chain 20, and at the same time provides a structure that is relatively resistant to bending under pressure. The reinforcing flanges 48, 50, 72 and 74 add to this structural integrity. I

Obviously, many modifications and variations of the present invention are possible, without departing from the invention as herein shown and described.

the free upper edge thereof.

5. In a chain saw, a saw bar having a rounded tip and lateral edge portions; a saw chain received 'on the edge of said saw 1 bar; a guard assembly comprising a pair of guard members,

each of s aid members including an attachment flange portion terminating in an upper edge, a spacer strip portion connected to the upper edge of said attachment flange portion and extending upwardly and outwardly at an acute angle, and a shield flange portion connected to extend upwardly from said spacer strip portion and lying parallel to said attachment flange portion, said guard members being disposed on the op posite faces of one lateral edge of said saw'bar in confronting relationship, with said attachment flange portions engaging said saw bar and said upper edges being spaced below said saw chain; and'means for removnbly securing said attachment flange portions to said saw bar, said shield flange portions ex tending asuhstantinl distance above said saw chain. 6. in a chain saw as recited in claim 5, wherein said spacer strip portions are inclined at about a 30 angle.

7. In a chain saw as recited in claim 5, wherein said shield flange portions terminate in upper edges having reinforcing flanges thereon.

members are each formed from a single piece of sheet metal.

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