Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACKGROUND OF THE INVENTION
Generally speaking, the present invention pertains to a timing
mechanism which comprises an axially indexable shaft; cam means carried
by and coupled to the shaft and including a cam having a cam profile
and at least one notch in the cam profile; means coupled to the shaft
applying rotation thereto; and detent means providing a starting
point for rotation of the cam means including a spring biased pawl
selectively operable to one of three positions: 1) engaged with the
cam profile, 2) engaged with the notch, and 3) disengaged from both
.the cam profile and the notch.
The present invention relates to a timing mechanism and more
particularly to a detent means used in the timing mechanism to provide
a selectable starting point of a program provided by the cam means
of a timing mechanism
Timing mechanisms have been used for many years in the appliance
industry to control the functions of appliances such as washers,
dryers, and dishwashers. In recent years because of the relatively
large variety of applications, the timing mechanisms have provided a
large variety of programs which the appliance operator may or may not
wish to use at any given time. Therefore, the timing mechanisms usually
provide some sort of detent means which permits the operator to manually
select a desired startlng point in a program in situations where the
complete program is not needed. Accordingly, the present invention
relates to such a detent means.
OBJECTS OR FEATURES OF THE INVENTION
It is therefore, a feature of the present invention to provide
a timing mechanism having a detent means to provide a starting point
in a program of the timing mechanism. Another feature of the invention
is to provide such a timing mechanism wherein there is a cam means
having a cam with a cam profile and at least one notch in the cam profile
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and a spring biased detent pawl cooperating with the cam profile and
- the notch to provide the starting point. Another feature of the invention
is to provide such a timing mechanism wherein the detent pawl is
actuated by the cam profile during a detenting mode and is further
actuated by an axial indexing of a shaft carrying the cam means during a
non-detenting mode. Still another feature of the invention is the
provision of such a timing mechanism wherein the spring biased detent
pawl is selectively operable to one of three positions: 1) engaged
with the cam profile, 2) engaged with the notch, and 3) disengaged from
both the cam profile and the notch. These and other features of the
invention will become apparent from the following description taken
in conjunction with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
Figure 1 is a side view of a timing mechanism with portions
removed to show the feature of the invention.
Figure 2 is an enlarged section taken along the line 2-2 of Figure
1.
Figure 3 is a view similar to Figure 2 showing the invention in
a different operating mode.
Figures 4-6 are views showing the relationship between a detent
pawl and a cam means of the timing mechanism in three different operating
modes.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to Figure 1, there is shown a timing mechanism 10
which, in general, includes a cam means 12 which is carried on a shaft 14
the cam means being coupled to a motor drive means 16 through motor
output pinion 18 and intermediate gearing 20. The manner in which the
motor drive means is connected to the cam means does not form a part
of the present invention and, therefore, for the sake of simplicity,
is not shown in detail. As shown, the cam means is housed in a
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housing 22 which includes end plates 24 and 26 and in which shaft
14 is rotatably journalled and, as will be herein described, is also
axially indexable. Although not shown, electrical switches engage
cam means 12 to open and close electrical circuits to electrical
.terminals 28. According to the present invention, there is provided
a detent means 30 which permits an operator to manually set cam
means 12 to a desired starting point for power driven rotation by
motor drive means 16.
Referring now to Figure 2, cam means 12 includes a plurality of
.cams 32 which are integrally constructed with a hub portion 34 that
is rotatably journalled on shaft 14. Hub 34 includes a yake portion
36 having oppositely disposed slots 38 through which legs 40 and 42
of hub 44 extend. Hub 44 is fixed to shaft 14 through cooperating
splines 46. Thus, rotation of cam means 12 causes rotation of shaft
14 through the cooperation of hubs 34 and 44. Shaft 14 is axially
indexable within hub 34 to one of two positions determined by spring
detent 48 engaging either one of grooves 50 or 52 of shaft 14.
Referring to Figure 2 and any one of Figures 4-6, cam means 32
1ncludes cam 54 which has a cam profile 56 and at least one notch 58.
Cam 54 cooperates with detent means 30 to provide a starting point from
which cam means 12 can be rotated. Detent means 30 includes a spring biased
detent pawl 60 which slideably engages a slot 62 of plate 24 and which
is guided through tabs 64 and 66 riding on the plate. As shown, detent
pawl 60 includes a ramp portion 68 which engages the ramp means 70
provided on hub 40. The detent pawl is axially spring biased through
a coil spring 72 which is carr~ed on a tab 74 which extends from the
cut-away edge 76 of plate 24 and a tab 75 which extends from the pawl.
As shown, the coil spring engages an end of a detent pawl 60 and cut-
away edge 76. The detent pawl also includes a tongue 78 which engages
cam 54 of cam means 32. As will be hereinafter explained, the detent
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pawl is selectively operable in three positions through either a
manual indexing of shaft 14 or the cam profile 56 of cam 54.
The operation of the detent means 30 with respect to cam means 12
and especially cam 54 can now be described. Starting with Figure 4,
tongue 78 is engaged with cam profile 56. The appliance operator manually
turns shaft 14 and thus cam means 12 through a handle (not shown)
carried on the end 14a of the shaft (Figure 1) until a desired notch
58 is engaged by the tongue 78 (detenting mode) as shown in Figures
3 and 5. It is understood that the operator is able to manually turn
the shaft by overriding motor drive means 16 through a clutch in the
intermediate gearing 20 located between the motor means and the cam
means in a manner well known in the art. If the first notch engaged
by the tongue does not represent the desired starting point, the operator
is able to continue rotation of the cam means by virtue of the tongue
riding out of the notch through ramp 59.
Once the desired starting point is reached, the operator pulls
the shaft 14 "out" to index the shaft to the position shown in Figure 2
where, as shown, ramp 70 has caused detent pawl 60 to move "out" through
engagement with ramp 68 of the pawl. Such movement of the pawl causes
disengagement of the tongue 78 from both notch 58 and cam profile 56
(non-detenting mode, Figure 6). Electrical power is then applied to
the ~iming mechanism until the desired cycle is completed. Upon
completion, the operator then pushes shaft 14 "in" to disengage ramps
68 and 70 and permit the pawl and tongue 78 to return to the position
of Figure 4.
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