Endless belt power transmission systems or components – Positive drive pulley or guide roll – And additional coaxial surface for engaging same belt in...
Patent
1980-10-30
1983-09-27
Staab, Lawrence J.
Endless belt power transmission systems or components
Positive drive pulley or guide roll
And additional coaxial surface for engaging same belt in...
474171, F16H 5530, F16H 5542
Patent
active
044066457
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
Heretofore the brake drum and sprocket were affixed to each other as by brazing or tab in slot connections so as to form a combined subassembly of the drive assembly or coupling. However, this was expensive and added complexity and steps to the assembly of the drive system of the chain saw. Also, since a high degree of skill was involved in producing the subassembly it might result in a higher than average rate of rejected parts.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved sprocket-brake drum construction for chain saw which overcomes the disadvantages of the prior art; which is economical, reliable and simple; which detachably connects the brake drum and the sprocket to the drive shaft; which mechanically connects the brake drum and the sprocket; which has lugs integrally formed on the brake drum; which lugs fit into openings between adjacent pairs of teeth of the sprocket; which lugs have a locking edge; which lugs are formed equidistant from each other along a circumferential line; which lugs will wear into uniform teeth engagement; which has a drive coupling with a clutch; which lugs are punched; and which lugs are semi-punched.
Other objects and advantages will be apparent from the following description of the invention, and the novel features will be particularly pointed out hereinafter in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
This invention is illustrated in the accompanying drawings in which:
FIG. 1 is a perspective view, partially cutaway, of a chain saw showing the novel sprocket-brake drum assembly of the present invention, without showing the brake band on the brake drum and only a dotted line representation of the saw chain on the sprocket.
FIG. 2 is an exploded, enlarged perspective view of the sprocket-brake drum assembly of FIG. 1.
FIG. 3 is a perspective view of the connection of the sprocket-brake drum taken alone showing the lugs engaged in alternate openings between adjacent teeth.
FIG. 4 is an elevational view, partly in section taken along line 4--4 of FIG. 1 showing the sprocket-brake drum assembly of the present invention.
FIG. 5 is an elevational view, partly in section taken along line 5--5 of FIG. 2, showing the lugs of the brake drum.
FIG. 6 is an enlarged sectional view taken along line 6--6 of FIG. 3 showing the semi-punched holes which produce the lugs of the brake drum.
FIG. 7 is an enlarged sectional view of another embodiment of the lugs, showing the lugs of the brake drum punched through therein.
DESCRIPTION OF THE INVENTION
A portable hand-held chain saw designated generally 10 is shown in FIG. 1 and embodies the present invention. The chain saw 10 has a housing 12 to which is affixed by a fastener 14 a guide or saw bar 16 which extends forwardly therefrom. An endless saw chain 18 is entrained on the saw bar and the links 20 thereof are driven by a sprocket 22 detachably mounted to a drive shaft or spindle 24 by a screw or bolt fastener 26 as illustrated in FIGS. 2 and 4.
The housing 12 has a rear handle 28 and a transversely disposed forward handle 30 in superposition to a motive means as, for example, an electric motor (not shown) housed in a motor casing 32 to drive the drive shaft through a gear train (not shown). The motor is connected to a source of electricity by a cord 34 and actuated by a trigger switch 36 which is depressed to turn the motor on. The handle 28 has an enclosed and widened lower portion 38 which serves to cover the operator's hand from contact from beneath. An oiler system, manual or automatic, may be used with the chain saw 10 with the oil cap 40 thereof being disposed on top of the handle 28 immediately behind the handle 30.
Forwardly of the handle 30 is a brake lever 42 shown in FIG. 1 in the nonoperative position, which when pivoted clockwise toward the saw bar 16 will be in the braking position as discussed hereinafter.
The drive assembly or coupling 44 has sleeve bearings 46 and 48 mounted on the drive shaft 24 with the sprocket 22, made of an oil impr
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Dynie Ernest R.
Lipscombe Ronald J.
Overy Colin
Bednarek Michael D.
Black & Decker Inc.
Sherer R. B.
Staab Lawrence J.
Weinstein Harold
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