Tape guide with lubricant flow preventing means in a signal recording arrangement

A tape guide mechanism includes absorbent members retained by a mounting structure so positioned as to absorb lubricant leakage from bearing portions of the tape guide mechanism to outer tape contact surfaces of a roller guide portion of flange portions thereof. The lubricant absorbing members may be mounted at a plurality of locations so as to prevent leakage of lubricant along an inner wall of the cylindrical roller guide portion of the tape guide, leakage along an outer surface of a support shaft of the tape guide, or leakage along inner or outer surfaces of a bearing pressing member provided at ends of the tape guide mechanism adjacent the flange portions thereof.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
As is known the height of magnetic tape moving during operation of a tape 
recording/playback device, such as a video tape recorder (VTR) or the 
like, is subject to fluctuation. Thus a plurality of tape guide members 
including flanges for limiting movement of the tape in the width direction 
thereof are included in a tape drive mechanism to stabilize tape motion. 
2. Description of the Related Art 
The present invention relates generally to a tape guide mechanism for use 
in such as video tape recorders (VTRs), and various types of rotary head 
tape devices. 
Conventional structure of such tape guide arrangements will be described 
hereinbelow with reference to FIGS. 1-4 wherein like reference numerals 
will be used to describe like parts. In FIG. 3 a circular bearing 51 is 
disposed around a main shaft 31. Upper and lower sides of the shaft are 
respectively retained by upper and lower bearings 37, 38. At ends of the 
shaft 31 flanges 40, 41 are respectively provided. 
Referring now to FIG. 1, generally, in such magnetic tape recording and/or 
reproducing apparatus utilizing such tape loading arrangements as 
described above, a pivotal arm 32 is moveably mounted on the base plate 
(not shown) for facilitating tape loading. Projecting from a distal end of 
the arm 32 a support shaft 31 is provided having a threaded end portion 
31a. 
At an upper side of the support shaft 31 a flange member 33 is provided 
having an enlarged circumferential ring portion 35 and a shaft section 34 
projected from a lower side thereof. The threaded and portion 31a of the 
support shaft 31 is engaged with a threaded opening 34a provided through 
said flange member 33 and the shaft section 34 thereof. 
A cylindrical roller guide 36 is disposed around said support shaft 31 to 
be held between a base of the support shaft 31 and the ring portion 35 of 
the flange 33 so as to be disposed coaxially with the support shaft 31 and 
to be rotatable relative thereto. The cylindrical roller guide 36 includes 
an outer tape contact surface 36a. 
A cylindrical bearing pressing member 43 is disposed coaxially with the 
support shaft 31 between the support shaft 31 and the roller guide 36. The 
bearing pressing member meets the upper flange 40 at an upper side thereof 
and the upper bearing 37 at the lower side thereof. 
The upper and lower sides of the support shaft 31 are respectively 
encircled by upper and lower bearings 37, 38. At upper and lower ends of 
the cylindrical roller guide 36 flanges 40, 41 are respectively provided 
retaining the upper and lower bearings 37, 38 therebetween. Fitting around 
a lower side of the support shaft 31 a flange spacer 44 is provided 
comprising a cylindrical spacer portion 44a and a flange ring portion 44b. 
Also, the flange spacer 44 is interposed between the lower edge of the 
lower flange 41 and the arm 32. 
Further, a coil spring 45 is provided which is fitted around a base portion 
of the support shaft 31 between the arm 32 and the flange ring portion 44b 
of the flange spacer 44. The coil spring 45 pushes the flanges 40 and 41 
in the upward direction and applies upward biasing pressure on the 
components of the tape guide mechanism engaged between the flange spacer 
and the flange 33. Further adjustment spacers 46, 47 may be normally 
provided in such a tape guide mechanism. The upper adjustment 46 spacer is 
positioned between a lower side of the bearing pressing member 45 and the 
upper bearing 37 while the lower adjustment spacer is positioned between 
an upper side of the lower flange 41 and the lower bearing 38. 
As may be seen in FIG. 4, each of the shaft receiving portions 37, 38 
includes an inner ring 62, and outer ring 63, a plurality of balls 64, 
ball support portions 65 and a sheild member 66. Further, in order that 
excessive frictional heat is not generated according to rotation of the 
balls 64, a lubricant such as grease (not shown) is generally disposed in 
the bearings 37, 38. 
According to provision of such lubricant, high performance may be obtained 
with smooth operation even during high speed rotation of the tape guide. 
However, according to such conventional tape guide structure, over 
prolonged use leakage of such grease or other lubricant may occur between 
the sheild 66 and the inner ring 62 and/or between the sheild 66 and the 
outer ring 63. In other words, the lubricant may be caused to move in the 
directions of the arrows as shown in FIG. 4 and the performance of the 
tape guide mechanism is degraded and it is possible that lubricant may be 
contacted to the tape surface, possibly damaging the magnetic tape. 
Thus, movement of lubricant in the directions as indicated in arrows a of 
FIG. 2 and arrows b-d or FIG. 3 may occur. Thus it has been required to 
provide a tape guide member in which lubricated bearings and the like are 
disposed such that migration of lubricant from the bearing to a tape 
contact surface such as the surface 36a of the roller guide or the inner 
sides off the flanges 40, 41, cannot occur. 
SUMMARY OF THE INVENTION 
It is therefore a principal object of the present invention to overcome the 
drawbacks of the related art. 
It is a further object of the present invention to provide a tape guide 
member in which migration of lubricant from bearing portions thereof to 
tape contact surfaces thereof is surely prevented. 
In order to accomplish the aforementioned and other objects, a tape guide 
mechanism for a signal recording apparatus is provided, comprising: a 
support shaft having upper and lower ends and projected from a mounting 
base; an upper flange engaged with a distal end of the support shaft and 
including a tape contact portion; a lower flange coaxially disposed around 
a lower side of the support shaft proximate the base and including a tape 
contact portion; a cylindrical roller guide disposed coaxially with the 
support shaft and rotatable relative thereto, disposed around the support 
shaft between the upper and lower flanges, the cylindrical roller guide 
including an outer tape contact surface and an inner wall; bearing means 
provided between an outer wall of the support shaft and the inner wall of 
the cylindrical roller guide; spring means provided between the base and a 
lower side of the lower flange so as to apply upward biasing pressure on 
components of the tape guide mechanism engaged between the upper and lower 
flanges; and annular lubricant flow prevention means provided between the 
bearing means and upper and lower ends of the tape guide mechanism, the 
lubricant flow prevention means positioned so as to intercept flow of 
lubricant between the bearing means and the tape contact surfaces of the 
upper and lower flanges and the cylindrical roller guide. 
According to another aspect of the present invention, there is provided a 
signal recording and/or playback apparatus utilizing magnetic tape, 
comprising: a head drum rotatably mounted on the apparatus and operable in 
a least one of a first mode for recording information signals to the 
magnetic tape and a second mode for reading information signals from the 
magnetic tape; at least one cylindrical tape guide mechanism rotatably 
disposed proximate the head drum and active to guide the magnetic tape 
along a predetermined path of tape travel, the tape guide mechanism 
including: a support shaft having upper and lower ends and projected from 
a mounting base; an upper flange engaged with a distal end of the support 
shaft and including a tape contact portion; a lower flange coaxially 
disposed around a lower side of the support shaft proximate the base and 
including a tape contact portion; a cylindrical roller guide disposed 
coaxially with the support shaft and rotatable relative thereto, disposed 
around the support shaft between the upper and lower flanges, the 
cylindrical roller guide including an outer tape contact surface and an 
inner wall; bearing means provided between an outer wall of the support 
shaft and the inner wall of the cylindrical roller guide; spring means 
provided between the base and a lower side of the lower flange so as to 
apply upward biasing pressure on components of the tape guide mechanism 
engaged between the upper and lower flanges; and annular lubricant flow 
prevention means provided between the bearing means and upper and lower 
ends of the tape guide mechanism, the lubricant flow prevention means 
being mounted on the inner wall of the cylindrical roller guide and 
positioned so as to intercept flow of lubricant between the bearing means 
and the tape contact surfaces of the upper and lower flanges and the 
cylindrical roller guide.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the accompanying drawings, a preferred embodiment of the 
invention will be described hereinbelow in detail. 
A first preferred embodiment of the invention will be explained hereinbelow 
in detail. The first embodiment is drawn to a tape guide and signal 
recording arrangement such as utilized in VTRs and the like. 
In the tape guide and signal recording arrangement according to the 
invention a fluid circuit provided for lubrication of the moving parts of 
the mechanism is prevented from leaking to an outer roller guide or flange 
surface of the tape guide. 
Referring to FIG. 5, it may be seen that a tape loading mechanism in which 
the tape guide and signal recording arrangement according to the invention 
may be utilized includes a rotating magnetic head drum 1 mounted on a base 
plate 2. Magnetic tape 4 from a tape cassette 3 is wound around the 
circumference of the head drum 1 and wound between reels 19 and 20 of the 
tape cassette 3 during recording and/or playback operation. Tape guides 5 
and 6 are provided respectively on each side of the head drum 1. The tape 
guides 5 and 6 include perpendicular guide members 5a, 6a and inclined 
guide members 5b, 6b. Also, supply side roller guides 7 and 8, supply side 
fixed guides 9 and 10 as well as take-up side fixed guides 11 and 12 and 
take-up side roller guides 13 and 14 also comprise the tape loading 
arrangement. A capstan 15, pinch roller 16, erase head 17 and a confidence 
head 18 may also be included. 
The magnetic tape 4 is moved according to operation of the tape guides 5 
and 6 and tape reel capstans (not shown) which are projected from the base 
plate 2 to support the tape reels 19 and 20 of the tape cassette 3. Thus, 
according to operation of the the supply side tape guide 5 or the take-up 
side tape guide 6 the magnetic tape 4 may be moved around the head drum 1 
in forward and reverse directions. 
Referring now to FIG. 6(a) and 6(b), a cross-sectional view and an enlarged 
cross-sectional view of a tape guide and signal recording arrangement 
according to the invention are shown. In the subsequent embodiments of 
FIGS. 7-14, like reference numerals will be used for like parts. 
Referring now to FIG. 1, generally, in such magnetic tape recording and/or 
reproducing apparatus utilizing such tape loading arrangements as 
described above, a pivotal arm 32 is moveably mounted on the base plate 
(not shown) for facilitating tape loading. Projecting from a distal end of 
the arm 32 a support shaft 31 is provided having a threaded end portion 
31a. 
At an upper side of the support shaft 31 a flange member 33 is provided 
having an enlarged circumferential ring portion 35 and a shaft section 34 
projected from a lower side thereof. The threaded and portion 31a of the 
support shaft 31 is engaged with a threaded opening 34a provided through 
said flange member 33 and the shaft section 34 thereof. 
A cylindrical roller guide 36 is disposed around said support shaft 31 to 
be held between a base of the support shaft 31 and the ring portion 35 of 
the flange 33 so as to be disposed coaxially with the support shaft 31 and 
to be rotatable relative thereto. The cylindrical roller guide 36 includes 
an outer tape contact surface 36a as described hereinabove in connection 
with the related art. 
A cylindrical bearing pressing member 43 is disposed coaxially with the 
support shaft 31 between the support shaft 31 and the roller guide 36. The 
bearing pressing member meets the upper flange 40 at an upper side thereof 
and the upper bearing 37 at the lower side thereof. 
The upper and lower sides of the support shaft 31 are respectively 
encircled by upper and lower bearings 37, 38. At upper and lower ends of 
the cylindrical roller guide 36 flanges 40, 41 are respectively provided 
retaining the upper and lower bearings 37, 38 therebetween. Fitting around 
a lower side of the support shaft 31 a flange spacer 44 is provided 
comprising a cylindrical spacer portion 44a and a flange ring portion 44b. 
Also, the flange spacer 44 is interposed between the lower edge of the 
lower flange 41 and the arm 32. 
Further, a coil spring 45 is provided which is fitted around a base portion 
of the support shaft 31 between the arm 32 and the flange ring portion 44b 
of the flange spacer 44. The coil spring 45 pushes the flanges 40 and 41 
in the upward direction and applies upward biasing pressure on the 
components of the tape guide mechanism engaged between the flange spacer 
and the flange 33. Further adjustment spacers 46, 47 may be normally 
provided in such a tape guide mechanism. The upper adjustment 46 spacer is 
positioned between a lower side of the bearing pressing member 45 and the 
upper bearing 37 while the lower adjustment spacer is positioned between 
an upper side of the lower flange 41 and the lower bearing 38. 
As seen in FIG. 6(a) and 6(b) in the tape guide and signal recording 
arrangement according to the invention lubricant flow prevention members 
71, 72 are provided adjacent inwardly facing ends of upper and lower 
bearing pressing members 43 and 51 respectively. The flow prevention 
members are annular rings affixed to an inner surface of the cylindrical 
roller guide 36. 
Further, on a side of each of the flow prevention members 71, 72 which 
faces the upper and lower bearings 37, 38, an annular groove is formed for 
containing lubricant which may flow from the bearings 37, 38 along the 
inner surface of the roller guide 36. According to the present embodiment, 
the annular groove 71a, 72a may be V-shaped. 
Further the letter `e` in FIG. 6(b) designates the direction of lubricant 
flow along an inner surface of a lower side the roller guide. As may be 
seen, flow of the lubricant is surely stopped by the annular groove 71a, 
72a of the flow prevention members 71, 72. That is, as mentioned above, 
when the tape recording and/or reproducing apparatus (not shown) in which 
the present tape guide mechanism is utilized is subjected to extended use, 
lubricant may be caused to flow from the bearing portions 37, 38 thereof. 
According to the invention, flow of lubricant to the tape contact 
surfaces, etc., is surely prevented. 
Further, the depth and position of the annular grooves 71a, 72a are so 
formed that lubricant caught therein will not fly out according to 
rotation of the roller guide during operational use. 
In addition, the invention is not limited to the flow prevention members 
71, 72 of the present embodiment but, referring now to FIGS. 7-9, may 
alternatively be formed of as porous annular members of synthetic resin 
such as urethane, for example. By provision of such annular members 81-83 
having porosity excess or leaked lubricant may be surely contained and 
increased working life and reliability is obtained. 
Further to the above, referring to FIG. 7, the porous annular members 81 
may be retained in annular flow prevention members 84, which according to 
the present embodiment are formed with an L-shaped cross-section such that 
the porous annular members are held in an annular groove 84a formed where 
the flow prevention members 84 are adhered to the inner wall of the roller 
guide 36. 
In the embodiment of FIG. 8 it may be seen that the porous annular member 
82 is firmly held against the inner wall of the roller guide 36 by the 
elastic properties of a flexible ring member 85 disposed at an inner 
periphery of the porous annular member 82 so as to apply expanding 
pressure thereto. 
The lubricant absorbing member 83 of FIG. 9 is itself formed of an elastic 
material and is held firmly against the inner wall of the roller guide 36 
by virtue of its own elasticity. 
Thus, the structure of a tape guide and signal recording arrangement 
according to the invention as described above is effective to prevent 
leakage of lubricant from bearings 37, 38 of the tape guide mechanism 
along the inner wall of a roller guide member 36 or from reaching tape 
contact surfaces 36a of the roller guide member or upper and lower flanges 
40, 41 of the tape guide. 
Next, a fifth embodiment of the invention will be set forth in detail 
describing a flow prevention arrangement for a tape guide mechanism for a 
case in which lubricant flow along an outer surface of a bearing pressing 
member is present, with reference to FIG. 10. 
As noted above, a tape guide and signal recording arrangement such as that 
of the invention may be provided with cylindrical bearing pressing members 
43, 51 at one or both of the upper and lower sides of the support shaft 
31. According to the present embodiment, each of the bearing pressing 
members 43, 51 is formed with a step portion 43a, 51a forming ring shaped 
groove 91 in the upper bearing pressing member 43 and ring shaped groove 
92 in the lower bearing pressing member 51. Each of the ring shaped 
grooves 91 and 92 are then filled with an annular lubricant absorbing 
member 93. Thus lubricant is prevented from running along the outer 
surface of the bearing pressing members 43, 51 and thus is prevented from 
being exposed to the tape contacting surfaces 36a of the roller guide 36 
or the tape contacting portions of the upper and lower flanges 40, 41. 
Thus, performance and reliability of the tape recording and/or reproducing 
apparatus is enhanced according to provision of the tape guide and signal 
recording arrangement according to the invention. 
Additionally, a situation must be considered in which lubricant from the 
bearings 37, 38 is caused to flow along an outer surface of the support 
shaft 31, thus leaking under the bearing pressing members 43 and/or 51 
along an inner surface thereof to escape at end portions of the support 
shaft, possibly to thereafter leak onto the tape contact surfaces of the 
flanges 40. 41 or the roller guide 36 so as to degrade performance of the 
tape recording and/or reproducing apparatus. In such case, the embodiment 
of FIG. 11 is provided. As may be seen from the drawing, according to this 
embodiment, the bearing pressing members 43, 51 are formed with small 
circumference portions and facing ends thereof having a circumference 
closely fitting the outer circumference of the support shaft 31 so as to 
fit snugly therearound. In addition, at ends thereof adjacent the flanges 
40, 41, the bearing pressing members 43, 51 of the present embodiment have 
larger circumference poritons wherein a space is present between the inner 
wall of the bearing pressing member 4,3 51 and the outer wall of the 
support shaft 31. 
At the stepped area between the smaller and larger circumference portions 
of the bearing pressing members 43, 51, and annular support rings 94, 95 
are formed projected from the inner walls of the larger circumference 
portion of each of the bearing pressing members 43, 51 respectively. The 
annular support rings define annular grooves 43b and 51b in each of the 
bearing pressing members respectively and an annular lubricant absorbing 
member 96 is disposed in each of the grooves 43b, 51b retained by the 
support rings 94, 95. Thus, leakage of lubricant from either of the 
bearings 37, 38 along the outer surface of the support shaft 31 or along 
the inner surface of the bearing pressing members is surely prevented and 
working life and performance of the tape guide and signal recording 
arrangement is enhanced. 
FIG. 12 shows another method of preventing lubricant flow from the inner 
side of the bearing pressing members 43, 51 and the outer side of the 
support shaft 31. According to this, a flow prevention member 100 having a 
lubricant absorbing surface 100a is integrally formed at a base edge of 
each of the bearing pressing members 43, 51 to be inserted into a inner 
opening of one of the upper and lower flanges 40, 41 respectively. 
According to this, the flow prevention members may be effectively and 
inexpensively provided. 
Referring now to FIG. 13, an alternative means of preventing lubricant flow 
from an outer surface of the support shaft 31 or from an inner surface of 
a bearing pressing member 43 or 51 is simple provision of an annular 
lubricant absorbing washer 110 at outward sides of the bearings 37, 38, 
immediately adjacent thereto. Such structure is particularly useful in a 
tape guide and signal recording arrangement such as described hereinabove 
wherein a lower bearing pressing member is not provided as the lubricant 
absorbing washer 110 may be provided between the bearing 37, 38 and the 
beaing pressing member 43, 51 or between the bearing 37, 38 and the flange 
40, 41, as desired. 
FIG. 14 shows an embodiment of the invention wherein three types of 
lubricant flow prevention means are provided at upper and lower sides of 
the tape guide mechanism respectively. According to this embodiment, 
lubricant flow of any kind is surely prevented from reaching the outside 
of the mechanism and tape contact surfaces are thus reliably protected 
from contamination due to lubricant leakage. According to this embodiment, 
the support structures of the embodiment shown in FIGS. 7, 10 and 11 are 
used for mounting annular lubricant absorbing members 120, 121, and 122 at 
both upper and lower sides of the tape guide mechanism. Thus, maximum 
reliability, longevity and operational quality may be assured. 
Thus, according to the preferred embodiments of the present invention as 
described hereinabove, an improved tape guide and signal recording 
arrangement is provided wherein lubricant provided in bearing portions of 
the tape guide is surely prevented from leaking to tape contact portions 
of the tape guide and this overall efficiency, reliability and work life 
of a tape recording and/or reproducing apparatus is definitively enhanced. 
While the present invention has been disclosed in terms of the preferred 
embodiment in order to facilitate better understanding thereof, it should 
be appreciated that the invention can be embodied in various ways without 
departing from the principle of the invention. Therefore, the invention 
should be understood to include all possible embodiments and modifications 
to the shown embodiments which can be embodied without departing from the 
principle of the invention as set forth in the appended claims.