BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an exemplary mixer;
FIG. 2 is a side elevation of the mixer of FIG. 1;
FIG. 3 is a partial cross-section of a sealing arrangement;
FIG. 4 is a partial perspective of the sealing arrangement;
FIG. 4A is a section view along lines A-A of FIG. 4;
FIG. 5 is a partially exploded view of the sealing arrangement; and
FIG. 6 is a section view of an embodiment of a seal in the sealing arrangement of FIG. 3.
DETAILED DESCRIPTION
Referring to FIGS. 1 and 2, a mixing machine 10 includes a mixer body 12 having a base portion 14, a head portion 16 and a support portion 18 (e.g., in the form of a column) connecting the head portion and the base portion in a vertically spaced apart relationship. A front to back head portion axis A is shown. An output member 20 (e.g., a shaft for receiving a mixer tool such as a beater or whip) extends downward from the head portion 16 in a direction toward a bowl receiving location 22 formed between the arms 24 of a bowl receiving yoke that can be moved upward and downward relative to the head portion 16 by rotation of the illustrated handle. A motor 26 may be mechanically linked to the output member 20, as by a gear system 28, for effecting rotation of the output member about a first axis 30 and orbiting movement of the output member 20 and first axis 30 about a second axis 32 (e.g., commonly referred to as a planetary movement or planetary rotation). A power take off 34 extends outwardly from a front side of the head portion 16 and may take the form of a protruding hub or boss that is adapted for connection with mixer accessories such as meat grinders, slicers etc. Internal of the power take off 34 is a drive member that is rotated by the motor 26 via the gear system 28. Head cover 40 is shown installed in FIG. 1, but is removed in FIG. 2.
An exemplary mix position of a bowl 50 is shown schematically in FIG. 2, along with an exemplary position of a bowl guard assembly 52. Bowl guard support 54 is located at the underside of the head portion 16 of the mixer and supports at least part of the bowl guard assembly 52 in a manner that enables the part to be moved between a bowl guarding position and a bowl access position.
Referring to FIG. 3, a partial cross-section of the gearing and bearing arrangement for output shaft 20 is shown. FIG. 4 shows a partial perspective of the same arrangement and FIG. 5 shows a partially exploded view. A lower portion 100 of the mixer head is a shaft receiving portion and includes a vertically extending opening or bore with an internal bearing support shoulder 102 that is located below an upper end 105 of the shaft receiving portion. The bearing support shoulder 102 holds a bearing 104 through which the upper end of shaft 20 extends for connecting with a gear 106. The bearing 104 is located below the upper end 105 of the shaft receiving portion 100 thereby defining a shaft seal receiving volume. The gear 106 is supported on the bearing 104 and the shaft is supported by the gear 106 (e.g., via a snap ring (not shown) at the top of the shaft). In this regard, referring also to FIG. 4A, a splined or other keyed connection is provided between the outer surface of the shaft 20 and the internal surface of the gear 106 such that rotation of the gear 106 effects rotation of the shaft 20. The axial spline slot 120 may extend from an upper portion of the gear 106 only partially downward (i.e., not all the way to the bottom side of the gear) to aid in limiting or avoiding moisture travel downward along the spline path toward the bearing 104. Likewise, a corresponding spline slot 122 on the upper portion of shaft may terminate before the bottom side of the gear 106 when the gear 106 is placed on the shaft. A spline 125 can be inserted into the aligned slots 120 and 122 when they are facing each other. The spline 125 may include a removal feature 127 to aid in removing the spline from the slots. In an alternative embodiment, the gear 106 may include the spline instead of the spline slot 120.
In addition, a seal 110 is provided below the gear 106 within the shaft seal receiving volume and includes an inner seal lip 112 that is inwardly biased against the outer surface of the lower end of the gear 106 to further aid in limiting or preventing moisture travel downward toward the bearing 104, as well as an outer seal lip 114 pressing against the housing portion 100. The outer seal lip 114 may be fairly rigid/stiff and press fit into the housing bore to provide its sealing function. A cap 108 may placed in the top opening of the gear 106 to aid in limiting or preventing moisture from entering the internal space of the gear 106.
At a lower portion of the shaft an additional bearing 115 is provided to maintain the shaft in a vertical orientation and to handle upward reactionary forces of the shaft 20. The housing bore includes a downward facing bearing shoulder 150 for this purpose. The bearing 115 is located above a lower end 119 of the shaft receiving portion 100 thereby defining a shaft seal receiving volume. A seal 116 is provided below bearing 124 and within the shaft receiving volume, with seal 116 having a configuration similar to seal 110 and aiding in limiting or preventing moisture egress upward toward bearing 115.
Referring to FIG. 6, seal 110 is a shaft seal that includes the inner lip 112 and the outer lip 114 and a U-shaped (cross-section) channel 130 formed therebetween. The inner lip 112 may be formed of a relatively resilient, flexible material such as an elastomer and the outer lip 114 may be formed of a relatively stiff material such as stainless steel. A biasing member 126, such as a coil spring (e.g., a garter spring) is used to provide a clamping force that biases the inner lip 112 away from the outer lip 114, in the direction of arrow 128 and toward the outer surface of the lower end of the gear 106. Seal 116 can include similar features. As one example, the seals 116 and 110 are commercially available from deVries International of Irvine, Calif.
The bearing space below seal 110 and above seal 116 may be packed with grease. Use of the sealing arrangement limits ingress of moisture into the space from either above or below, which ingress could affect bearing life.
It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation, and that changes and modifications are possible. Accordingly, other embodiments are within the scope of the following claims.