Claims:We claim:

1. A sealing arrangement for vertically reciprocating shaft, wherein the arrangement comprises:

• a shaft assembly vertically moving in the guide bore of the top link of the spindle assembly;

• a plurality of seals disposed at the upper and lower ends of the top link of the spindle assembly;

wherein a close radial clearance is provided between the guide bore and the spindle of the top link of the spindle assembly for guiding the vertically reciprocating shaft.

2. Sealing arrangement as claimed in claim 1, wherein the arrangement is maintained under zero pressure for working the top link spindle assembly subjected to side loads, particularly generated during off-load applications.

3. Sealing arrangement as claimed in claim 1 or 2, wherein the sealing arrangement is a mechanism comprising:

• a Vary Touch Unit (VTU) housing,

• a bell crank,

• a trunnion top link spindle,

• a rubber boot,

• a scrapper or wiper seal disposed at the upper end of the top link of the spindle trunnion assembly,

• a rod seal disposed at the lower end of the top link of the spindle trunnion assembly,

• a top link spindle assembly,

• a transmission case,

• a plurality of fasteners and washers, and

• a plurality of springs disposed about the spindle rod for facilitating the vertical movement of the spindle trunnion assembly.
4. Sealing arrangement as claimed in claim 3, wherein an upper spring is enclosed within the rubber boot supported between a pair of washers abutting the trunnion top link spindle at the upper end thereof and abutting the scraper or wiper seal at the lower end thereof.

5. Sealing arrangement as claimed in claim 3, wherein a lower spring is seated between an upper seat and a lower seat disposed inside the transmission case, wherein the upper seat supports the rod seal at bottom side of the top link assembly to prevent oil leakage from the transmission case.

6. A sealing arrangement for vertically reciprocating shaft maintained under zero pressure, wherein the arrangement comprises:

• a top link spindle assembly vertically moving in the guide bore of the Very Touch Unit (VTU) housing;

• a bell crank subjected to side loads generated during off-load applications, such as ploughing,

• the top link spindle assembly fitted between the trunnion top link spindle of the bell crank and the transmission case;

wherein a close radial clearance is provided between the guide bore and the spindle of the top link spindle assembly for a vertical reciprocation thereof.

7. Sealing arrangement as claimed in claim 6, wherein an upper spring is enclosed within the rubber boot supported between a pair of washers abutting the trunnion top link spindle at the upper end thereof.

8. Sealing arrangement as claimed in claim 7, wherein the rubber boot assembly abuts the scraper or wiper seal at the lower end thereof.

9. Sealing arrangement as claimed in claim 8, wherein a lower spring is placed between an upper seat and a lower seat disposed inside the transmission case.

10. Sealing arrangement as claimed in claim 9, wherein the upper seat supports a rod seal at bottom side of the top link assembly to prevent oil leakage from the transmission case.

Dated: this 23rd day of January, 2017. SANJAY KESHARWANI
APPLICANT’S PATENT AGENT , Description:FIELD OF INVENTION

The present invention relates to sealing arrangement for a vertically reciprocating shaft. In particular, the present invention relates to a sealing arrangement for a vertically reciprocating shaft working under zero bar pressure. More particularly, the present invention relates to a sealing arrangement for a vertically reciprocating shaft working under side loads.

BACKGROUND OF THE INVENTION

Conventional vertically reciprocating shafts are normally located in guide rings to avoid side loads and to provide good sealing. Here, the shaft is guided in the parent body (in this case Vary Touch Unit housing) without using any guide rings, thus eliminating the requirement of guide ring assembly. The seals are placed on opposite sides of guide bore to balance the load on shaft, because the shaft requires an accurate sensing for hitch regulation, i.e. It's response to the compressive as well as tensile loads. This is very critical in applications like soil leveling etc. A higher load delays or lags the shaft movement, thereby causing a delayed signal to the control valve.

PRIOR ART

In the prior arts searched, the hydraulic cylinder arrangement did not require an accurate movement of shaft mandatorily.

US 2013/0043661 A1 discloses the device, system, and method directed to seal assemblies with support to reduce seal extrusion under high to very high pressure changes due to repeated piston reciprocating movement. In some examples, concave features are incorporated on the inner and outer edges of support and backup ring elements to support and hug the preceding element and constrain extrusion, as well as utilizing multiple contact points on certain elements in order to reduce friction against the dynamic surface. The seal assemblies described herein can also incorporate bearing surfaces to reduce damage to seal ID due to off-axis floating rod, such as incorporating one or more multi-point contacts to reduce friction.
However, this invention relates to seals for sealing a dynamic surface and a static surface, for example spring energized seal assemblies for reciprocating applications in which a shaft reciprocates back-and-forth

JP 2009236177 A discloses a sealing structure which keeps a stable sealing performance, and plans to suppress mechanical loss. The sealing structure is characterized in that on one side surface of an annular groove 61, a projection 62 including a slant surface 62a inclining from a groove bottom side to a surface of a shaft 50 as it goes from the one side surface side to the other side surface side, is arranged, a sealing device 10 extends from the one side surface side to the other side surface side, and provides a seal lip 12 slidably contacting the surface of the shaft 50, and near a lip root of the seal lip 12, a slant surface 12b closely contacting the slant surface 62a in the projection 62 at fluid pressure application is formed.

However, the invention relates to a sealing structure for sealing an annular gap between the shaft hole provided in the shaft and the housing.

DISADVANTAGES WITH THE PRIOR ART

The following are the disadvantages with the sealing arrangements discussed above:

• Guide rings are required for reducing friction against dynamic surfaces.

• No side loading possible.

• Function under high pressures.

• Energizer is required for enabling the backup ring or support ring to function as a bearing.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide a sealing arrangement for a vertically reciprocating shaft which uses the features of the existing guide rings.

Another object of the present invention is to provide a sealing arrangement for a vertically reciprocating shaft which uses a balanced sealing for rod sensing.

Still another object of the present invention is to provide a sealing arrangement for a vertically reciprocating shaft, in which side loads can be applied on the shaft.

Yet another object of the present invention is to provide a sealing arrangement for a vertically reciprocating shaft, which is mechanically operated.

A still further object of the present invention is to provide a sealing arrangement for a vertically reciprocating shaft which is applicable to all vertically reciprocating shafts assemblies.

A yet further object of the present invention is to provide a sealing arrangement for a vertically reciprocating shaft which is particularly applicable in off-road applications subjected to dust, water, slurry and contaminations.

These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.

SUMMARY OF THE INVENTION

In a first embodiment of the present invention, there is provided a sealing arrangement for vertically reciprocating shaft, wherein the arrangement comprises:

• a shaft assembly vertically moving in the guide bore of the top link of the spindle assembly;

• a plurality of seals disposed at the upper and lower ends of the top link of the spindle assembly;

wherein a close radial clearance is provided between the guide bore and the spindle of the top link of the spindle assembly for guiding the vertically reciprocating shaft.

Typically, the sealing arrangement is maintained under zero pressure for working the top link spindle assembly subjected to side loads, particularly generated during off-load applications.

Typically, the sealing arrangement is a mechanism which comprises:

• a Vary Touch Unit (VTU) housing,

• a bell crank,

• a trunnion top link spindle,

• a rubber boot,

• a scrapper or wiper seal disposed at the upper end of the top link of the spindle trunnion assembly,

• a rod seal disposed at the lower end of the top link of the spindle trunnion assembly,

• a top link spindle assembly,

• a transmission case,

• a plurality of fasteners and washers, and

• a plurality of springs disposed about the spindle rod for facilitating the vertical movement of the spindle trunnion assembly.

Typically, an upper spring is enclosed within the rubber boot supported between a pair of washers abutting the trunnion top link spindle at the upper end thereof and abutting the scraper or wiper seal at the lower end thereof.

Typically, a lower spring is seated between an upper seat and a lower seat disposed inside the transmission case, wherein the upper seat supports the rod seal at bottom side of the top link assembly to prevent oil leakage from the transmission case.

In another embodiment of the present invention, there is also provided a sealing arrangement for vertically reciprocating shaft maintained under zero pressure, wherein the arrangement comprises:

• a top link spindle assembly vertically moving in the guide bore of the Very Touch Unit (VTU) housing;

• a bell crank subjected to side loads generated during off-load applications, such as ploughing,

• the top link spindle assembly fitted between the trunnion top link spindle of the bell crank and the transmission case;

wherein a close radial clearance is provided between the guide bore and the spindle of the top link spindle assembly for a vertical reciprocation thereof.

Typically, an upper spring is enclosed within the rubber boot supported between a pair of washers abutting the trunnion top link spindle at the upper end thereof.

Typically, the rubber boot assembly abuts the scraper or wiper seal at the lower end thereof.

Typically, a lower spring is placed between an upper seat and a lower seat disposed inside the transmission case.

Typically, the upper seat supports a rod seal at bottom side of the top link assembly to prevent oil leakage from the transmission case.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, wherein:

Figure 1 shows a sealing arrangement for a vertically reciprocating shaft configured in accordance with the present invention.

Figure 2 shows a schematic representation of the sealing arrangement of figure 1 used in a vertically reciprocating shaft.
Figure 3 shows a detailed cross-sectional view of the sealing arrangement of Fig. 1.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, the sealing arrangement for a vertically reciprocating shaft configured in accordance with the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1 shows a sealing arrangement configured in accordance with the present invention for a vertically reciprocating shaft Sp reciprocating in a vertical direction inside a housing H. Accordingly, a twin-seal arrangement is provided for the vertically reciprocating shaft Sp working at zero bar pressure and applied with side loads SL (Figure 2). Here, for providing an effective sealing, the twin-sealing arrangement configured according to the present invention facilitates the vertically reciprocating shaft to be guided in the parent body (VTU housing here) without using any guide rings and thus eliminating the requirement of a guide ring assembly. The twin seals (wiper seal Ws and rod seal Rs) are placed on opposite sides of guide bore Gb to balance the load on shaft Sp, since the shaft requires accurate sensing for hitch regulation, i.e. It's response to compressive as well as tensile loads. This is very critical in applications like soil leveling etc. A higher load delays or lags the shaft movement, thereby issues a delayed signal to the control valve. This arrangement can be applied in all vertically reciprocating shafts assemblies, particularly those used for off-road applications, which are often subjected to contaminations due to dust, water and slurry. Shaft Sp is supported and sealed with a reciprocating type wiper seal Ws adjacent the upper end of the spindle Sp and with another reciprocating type rod seal Rs adjacent the lower end thereof. A close or tight radial clearance Rc is provided for guiding the vertically reciprocating shaft Sp for side load applications, as prevailing in off-road applications, such as soil leveling, often subjected to contaminations due to dust, water and slurry.

Figure 2 shows a schematic representation of the sealing arrangement or mechanism SM of Figure 1 equipped with a Wiper seal Ws and Rod seal Rs and fitted on a vertically reciprocating shaft Sp subjected to side loads SL due to application requirements.

Figure 3 shows a detailed cross-sectional view of the sealing arrangement SM of Fig. 1. The mechanism includes a VTU housing 02, a bell crank 04, a spindle trunnion top link 06, a washer 08, a spring 10, a rubber boot 12, a scrapper or wiper seal 14, a rod seal 16, seat 18, another spring 20, a top link spindle assembly 22, a transmission case 24, nut 26 and another washer 28.

WORKING OF THE INVENTION

A sealing arrangement is provided in accordance with the present invention, which seals vertically reciprocating shaft Sp working at zero bar pressure and applied with side loads SL. This sealing arrangement facilitates the vertically reciprocating shaft to be guided in housing without using any guide rings, thus eliminating the requirement of a guide ring assembly, as in the conventional arrangements. The seals 16, 16 are placed on opposite sides of guide bore Gb of the top link spindle assembly 22 to balance the load on shaft, because the shaft requires accurate sensing for hitch regulation, i.e. It's response to both compressive and tensile loads. This is very critical in applications like soil leveling etc. Wiper/Scrapper seal 14 (Ws) is used to avoid contamination due to dust, water and slurry entry through top side and the rod seal 16 (Rs) is used at bottom side to avoid oil coming out of transmission case.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The sealing arrangement for a vertically reciprocating shaft configured in accordance with the present invention has the following technical and economic advantages:

• Features in the existing guide rings can be used.

• Balanced sealing is used for rod sensing requirement.

• Side loading can be taken on shaft, because the shaft is mechanically operated as against the hydraulically operated shaft in cylinders.

• Applicable to all vertical shafts assemblies requiring a reciprocating motion.

• Particularly applicable in off-road applications subjected to contaminations due to dust, water and slurry.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept. Therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification.

It is to be understood that the phraseology or terminology employed herein is for the purpose of description and the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the above description. The description provided herein is purely by way of example and illustration. The various features and advantageous details are explained with reference to this non-limiting embodiment in accordance with the present invention.

Therefore, while the embodiments herein have been described in terms of preferred embodiments, the skilled person will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments described herein and can easily make innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies, assemblies and in terms of the size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention.