DESC:PRIORITY STATEMENT

[001] The present application hereby claims priority from Indian patent application with the application number 202241071999, filed on 13 December 2022, the entire contents of which are incorporated herein by reference.

FIELD OF THE DISCLOSURE

[002] The present disclosure relates to a tailstock used in machining operation. More particularly, it relates to a sliding mechanism for a dead center in the tailstock.

BACKGROUND OF THE DISCLOSURE

[003] The following description of related art is intended to provide background information pertaining to the field of the disclosure. This section may include certain aspects of the art that may be related to various features of the present disclosure. However, it should be appreciated that this section be used only to enhance the understanding of the reader with respect to the present disclosure, and not as admissions of prior art.

[004] A tailstock is a part of a machine that is used to support a workpiece or a tool. The conventional tailstocks are used to ensure a work piece’s longitudinal rotary axis is held steady and fixed precisely parallel to a lathe bed.

[005] The tailstock’s position is adjusted along bed ways to accommodate work pieces of different lengths. Once the work piece is locked in place, a tool is mounted and moved into the exact position using a lead screw. In conventional tailstocks, the quill moves forward and backward within a long high precision bore. A minor deviation in dimensions of the high precision bore causes deviation in movement of the quill. Such deviation in movement also causes friction during quill movement, which is undesirable. Also, after a certain period of use, the generated friction causes uneasy movement of the quill and reduces the repeatability.
[006] Therefore, in light of the aforementioned drawbacks in the conventional tailstocks, there exists a need to develop an improved quill mechanism for proper positioning and movement of a dead center.

SUMMARY OF THE DISCLOSURE

[007] This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the disclosure. This summary is neither intended to identify key or essential inventive concepts of the disclosure nor is it intended for determining the scope of the disclosure.

[008] To overcome or at least mitigate one of the problems mentioned above in the state of the art, a tailstock is provided.

[009] The primary objective of the present disclosure is to achieve straight movement of quill without deviation.

[0010] Another objective of the present disclosure is to achieve high repeatability.

[0011] The further objective of the present disclosure is to achieve ease of movement in both forward and backward strokes.

[0012] In an embodiment of the present disclosure, a tailstock is disclosed. The tailstock comprises a stationary base block. A guide rail is mounted on the stationary base block. A guide block is movably disposed on the guide rail. A quill is mounted on the guide block. A dead center is coupled to the quill. A rotatable wheel is coupled to the quill via a lead screw mechanism. A guide plate and a bearing plate are coupled respectively to a front end and a rear end of the stationary base block. A locking unit is coupled to the guide plate, wherein the locking unit is configured to lock the quill at a predefined location along the guide rail.
[0013] To further clarify the advantages and features of the present disclosure, a more particular description of the disclosure will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the disclosure and are therefore not to be considered limiting of its scope. The disclosure will be described and explained with additional specificity and detail with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS
[0014] These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

[0015] Figure 1 illustrates an isometric view of tailstock according to an embodiment of the present disclosure;

[0016] Figure 2 illustrates a cross sectional view of the tailstock in accordance with the embodiment shown in Figure 1; and

[0017] Figure 3 illustrates a cross sectional view of a locking unit of the tailstock in accordance with the embodiment shown in Figure 1.

[0018] Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have necessarily been drawn to scale. For example, the flow charts illustrate the method in terms of the most prominent steps involved to help to improve understanding of aspects of the present disclosure. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiment of the present disclosure so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.
DETAILED DESCRIPTION OF FIGURES

[0019] For the purpose of promoting an understanding of the principles of the present disclosure, reference will now be made to the various embodiments and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the present disclosure is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the present disclosure as illustrated therein being contemplated as would normally occur to one skilled in the art to which the present disclosure relates.

[0020] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are explanatory of the present disclosure and are not intended to be restrictive thereof.

[0021] Whether or not a certain feature or element was limited to being used only once, it may still be referred to as “one or more features” or “one or more elements” or “at least one feature” or “at least one element.” Furthermore, the use of the terms “one or more” or “at least one” feature or element do not preclude there being none of that feature or element, unless otherwise specified by limiting language including, but not limited to, “there needs to be one or more…” or “one or more elements is required.”

[0022] Reference is made herein to some “embodiments”. It should be understood that an embodiment is an example of a possible implementation of any features and/or elements of the present disclosure. Some embodiments have been described for the purpose of explaining one or more of the potential ways in which the specific features and/or elements of the proposed disclosure fulfil the requirements of uniqueness, utility, and non-obviousness.

[0023] Use of the phrases and/or terms including, but not limited to, “a first embodiment,” “a further embodiment,” “an alternative embodiment,” “one embodiment,” “an embodiment,” “multiple embodiments,” “some embodiments,” “other embodiments,” “further embodiment”, “furthermore embodiment”, “additional embodiment” or other variants thereof do not necessarily refer to the same embodiments. Unless otherwise specified, one or more particular features and/or elements described in connection with one or more embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may be found in no embodiments. Although one or more features and/or elements may be described herein in the context of only a single embodiment, or in the context of more than one embodiment, or in the context of all embodiments, the features and/or elements may instead be provided separately or in any appropriate combination or not at all. Conversely, any features and/or elements described in the context of separate embodiments may alternatively be realized as existing together in the context of a single embodiment.

[0024] Any particular and all details set forth herein are used in the context of some embodiments and therefore should not necessarily be taken as limiting factors to the proposed disclosure.

[0025] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such process or method. Similarly, one or more devices or sub-systems or elements or structures or components proceeded by “comprises... a” does not, without more constraints, preclude the existence of other devices or other sub-systems or other elements or other structures or other components or additional devices or additional sub-systems or additional elements or additional structures or additional components.

[0026] Functionality of different parts used in the tailstock are as follows:

? Guide Rail: It acts as a carriage for guide block, guiding the motion of the dead center.
? Guide Block: It runs on a carriage and carries a quill.
? Quill: It is mounted on a guide block and is used to hold the dead center.
? Guide Plate: It guides the quill and provides location for the quill.
? Lead Screw Mechanism/Lead screw/Lead Nut: It converts rotary motion into linear motion.
? Stationary base block: It carries the whole assembly and holds tenon for guiding. Above this stationary base block, the guide rail is mounted. It ensures the guide rail is in position with respect to tenon.
? Locking unit: It is used to lock the dead center radially.
? Dead Center: It provides support for components while machining.
? Rotatable Wheel: It is used to rotate the leadscrew connected to it.
? Guide Bush: It acts as a guiding member for quill through the bore.
? Wiper Seal: It is used to wipe the dust and coolant coming from the exterior working atmosphere.
? Axial Roller Bearing: It acts as a support for lead screw and carries the load coming axially while having back and forth motion.
? Bearing Plate: It is used to hold the lead screw, axial roller bearing and rotary shaft seal firmly.

[0027] In view of the state of the art, there exists a need for a tailstock which is used for achieving i) straight movement of quill without deviation, ii) high repeatability, and iii) ease of movement in both forward and backward stroke.

[0028] In an embodiment of the present disclosure, a tailstock is disclosed. The tailstock comprises a stationary base block. A guide rail is mounted on the stationary base block. A guide block is movably disposed on the guide rail. A quill is mounted on the guide block. A dead center is coupled to the quill. A rotatable wheel is coupled to the quill via a lead screw mechanism. A guide plate and a bearing plate are coupled respectively to a front end and a rear end of the stationary base block. A locking unit is coupled to the guide plate, wherein the locking unit is configured to lock the quill at a predefined location along the guide rail.

[0029] Hereinafter, a tailstock according to an embodiment of the present disclosure will be described with reference to Figures 1 to 3. Figure 1 illustrates an isometric view of tailstock according to an embodiment of the present disclosure. As shown in Figure 1, the tailstock (100) includes a stationary base block (101), a guide rail (102), a guide block (103), a quill (104), a dead center (105), a rotatable wheel (106), a guide plate (107), a bearing plate (108), and a locking unit (109). The stationary base block (101) is used as a base of the tailstock (100) and carries the whole assembly. The stationary base block (101) is locked to a working bed using one or more connecting means such as bolts (137), washers (118) and T-nuts (134).

[0030] The guide rail (102) is mounted and locked on the stationary base block (101) using one or more connecting means. The guide block (103) is disposed on the guide rail (102). The guide block (103) and the guide rail (102) are utilized for linear movement of the quill (104) instead of conventional long high precision bore. The guide block (103) is moveable from one end to the other end along a linear direction on the guide rail (102). The guide rail (102) enables proper alignment of a workpiece during machining for metal cutting applications in various industries including but not limited to automobile, general engineering, aerospace components, electrical and electronic components, orthopedics components etc.

[0031] The quill (104) is mounted on the guide block (103) using one or more connecting means such as screws (136). Nylon stoppers (127) of different sizes are coupled to quill (104) using one or more connecting means. The nylon stoppers are used to arrest the motion of the quill (104) within the stroke limit.

[0032] The dead center (105) is coupled to the quill (104) using one or more connecting means. The quill (104) and the dead center (105) are movable forward or backward along the guide rail (102) and through the guide plate (107). In one embodiment, the stroke of the movement of the dead center (105) is 40 mm.

[0033] The rotatable wheel (106) is coupled to the quill (104). The forward and backward movement of the quill (104) is driven by a lead screw. The backward and forward motion of the lead screw is driven by the rotatable wheel (106) provided with knob handle (129).

[0034] The guide plate (107) and the bearing plate (108) are coupled respectively to a front end and a rear end of the stationary base block (101) using a connecting means such as screws (136).

[0035] The locking unit (109) is coupled to the guide plate (107). The locking unit (109) includes a clamp holder plate (110), a rotatable lever (111) (not shown in Figures), and a plurality of bushes (112, 113). The clamp holder plate (110) is detachably coupled to the guide plate (107) by one or more connecting means such as screws (136). The rotatable lever (111) is coupled to the clamp holder plate (110). The locking unit (109) is configured to lock the quill (104) at a predefined location along the guide rail (102). The rotatable lever (111) is rotated to lock the quill (104) at the required position.

[0036] A cover plate (123) is mounted on the top side of the bearing and guiding plates (108, 107) to cover a top side of tailstock (100) and is fixed by screws. Two sheet covers (not shown in Figure 1) are used to close the tailstock (100) at both right and left sides which are sealed by gasket and is fixed by screws. In order to avoid the leakage, the region between top cover plate (123) and sheet covers is sealed with a gasket. An eye bolt (133) is fixed on the lifting block (132) which is mounted on the cover plate (123) using screws (136).

[0037] Figure 2 illustrates a cross sectional view of the tailstock in accordance with the embodiment shown in Figure 1. As shown in Figure 2, the tailstock (100) includes the stationary base block (101), the guide rail (102), the guide block (103), the quill (104), the dead center (105), the rotatable wheel (106), the guide plate (107), the bearing plate (108), and the locking unit (109). The stationary base block (101) is used as a base of the tailstock (100) and supports the whole assembly. The stationary base block (101) is mounted on a plurality of guide tenons (139). The stationary base block (101) is locked to the working bed using one or more connecting means such as bolts (137), washers (118) and T-nuts (134).

[0038] The guide rail (102) is mounted and locked on the stationary base block (101) using one or more connecting means such as screws (136). The guide block (103) is disposed on the guide rail (102). The guide block (103) and the guide rail (102) are utilized for linear movement of the quill (104) instead of conventional long high precision bore. The guide block (103) is moveable from one end to the other end along a linear direction on the guide rail (102).

[0039] The quill (104) is mounted on the guide block (103) using one or more connecting means such as screws (136). The quill (104) is guided by a guide bush (140) provided at the guiding plate (107). Nylon stoppers (127) of different sizes are coupled to quill (104) using one or more connecting means. The nylon stoppers are used to arrest the motion of the quill (104) within the stroke limit.

[0040] The dead center (105) is coupled to the quill (104) using one or more connecting means. The quill (104) and the dead center (105) are movable forward or backward along the guide rail (102) and through the guide plate (107).

[0041] The rotatable wheel (106) is coupled to the quill (104) via a lead screw mechanism (114). The lead screw mechanism (114) includes a lead screw nut (115) and a lead screw (116). The rotatable wheel (106) is coupled to the quill (104). The forward and backward movement of the quill (104) is driven by a lead screw (116). The backward and forward motion of the lead screw (116) is driven by the rotatable wheel (106) provided with knob handle (129).

[0042] The guide plate (107) and the bearing plate (108) are coupled respectively to a front end and a rear end of the stationary base block (101), using a connecting means such as screws (136). The two dowel pins (125) are used for locating the guide plate (107) with stationary base block (101). The lead screw (116) is supported by an axial bearing (117), a lock nut (141), a lead screw nut (115) and a rotary shaft seal (122) at the bearing plate (108). The axial bearing (117) includes two washers (118) which function as support for rollers and location of the bearing. The bearing plate (108) supports the lead screw mechanism (114). The lead screw mechanism (114) is rotatable and movable along a linear direction.

[0043] A key (119) is inserted in the key race of the lead screw (116) and rotatable wheel (106). A special washer (120) is used along with O-ring (121) to lock the rotatable wheel (106) from the backside which is fixed by screw (136).

[0044] A cover plate (123) is mounted on the top side of the bearing and guiding plates (108, 107) to cover the top side of tailstock (100) and is fixed by screws (136). A grease nipple (124) is used to insert grease. A threaded plug (135) is used to cover the threaded hole at the backside of the bearing plate (108). A hollow rubber grommet (126) is used as a seal between knob handle (129) and side cover (130) at clamping side. On the other side a blank rubber grommet (128) is used to cover the blank hole on the other side cover (130). Two sheet covers (130) are used to close the tailstock (100) at both right and left sides which is sealed by gasket (131) and is fixed by screws (136). In order to avoid the leakage, the region between top cover plate (123) and side (right and left) plates is sealed with a gasket (131) (as shown in Figure 3).

[0045] An eye bolt (133) is fixed on the lifting block (132) which is mounted on the cover plate (123) using screws (136). A wiper seal (138) is placed above the quill (104). The wiper seal (138) is used to wipe the coolant and dirt from entering into tailstock (100). Two tenons (139) are fixed at the bottom of the stationary base block (101) using screws (136).

[0046] Figure 3 illustrates a cross sectional view of a locking unit of the tailstock in accordance with the embodiment shown in Figure 1. Similar to Figure 2, Figures 3 describes magnified version of the locking unit as described in Figures 1 and 2. The tailstock (100) includes the stationary base block (101), the guide rail (102), the guide block (103), the quill (104), the dead center (105), the rotatable wheel (106), the guide plate (107), the bearing plate (108), and the locking unit (109) .

[0047] As shown in Figure 3, the guide rail (102) is mounted and locked on the stationary base block (101) using one or more connecting means such as screws (136) and 2 dowel pins (125) (not shown in Figure). The guide block (103) is disposed on the guide rail (102). The guide block (103) and the guide rail (102) are utilized for linear movement of the quill (104) instead of conventional long high precision bore. The guide block (103) is moveable from one end to the other end along a linear direction on the guide rail (102).

[0048] The locking unit (109) is coupled to the guide plate (107). The plurality of bushes such as threaded bush (112), plain bush (113) and clamping bush (142) is disposed between the clamp holder plate (110) and a rotatable lever (111). The locking unit (109) is configured to lock the quill (104) at a predefined location along the guide rail (102). The rotatable lever (114) is rotated to lock the quill (104) at the required position.

[0049] The tailstock (100) of the present disclosure has the followings:
Dimensions (LxWxH): 374x157x209
Weight (Kg): 17.5
Stroke of the dead center (mm): 40 mm.

[0050] WORKING EXAMPLE OF THE PRESENT DISCLOSURE:
The tailstock works on a lead screw mechanism which is supported by guide rail and guide block for smooth forward and backward motion. The lead screw is connected to the rotatable wheel which when rotated in clockwise or anti clockwise direction, drives the lead nut in forward and backward motion. Since the lead nut is fixed to the quill, the quill which is carrying the dead center moves forward and backward which is guided by guide rail and guide block.

[0051] The lead screw is supported by an axial roller bearing located at the bearing plate which is fixed to the stationary base block at the backside. The quill is guided by a bronze bush located at the guiding plate which is fixed to the stationary base block at the front side. A wiper seal is used at the front side, located in the guiding plate bore that restricts the entry of coolant, dust and dirt from entering the tailstock during dead center motion. Similarly, a rotary shaft seal is used to restrict the coolant entry at the backside of the bearing plate during the lead screw motion.

[0052] A locking unit is used to lock the quill position. The locking unit consists of a locking plate with bore in it, a threaded plug and plain plug. These plugs are located in the locking plate in a direction perpendicular to the forward/backward motion of the dead center. The locking plate is fixed to the guide plate located at the dead center outer diameter (OD) with some clearance for free motion of the quill. When the adjustable lever is rotated to lock the tailstock, the locking plate inner diameter (ID) compresses and comes in contact with the OD of the quill, locking the quill at required position.

[0053] Advantages of the present disclosure:
The above-mentioned tailstock of the present disclosure provides the followings:
i) It provides straight movement of quill without deviation;
ii) It provides high repeatability; and
iii) It provides ease of movement in both forward and backward strokes.

[0054] In this application, unless specifically stated otherwise, the use of the singular includes the plural and the use of “or” means “and/or.” Furthermore, use of the terms “including” or “having” is not limiting. Any range described herein will be understood to include the endpoints and all values between the endpoints. Features of the disclosed embodiments may be combined, rearranged, omitted, etc., within the scope of the disclosure to produce additional embodiments. Furthermore, certain features may sometimes be used to advantage without a corresponding use of other features.

[0055] List of reference numerals:
Components Reference numerals
100 Tailstock
101 Stationary base block
102 Guide rail
103 Guide block
104 Quill
105 Dead center
106 Rotatable wheel
107 Guide plate
108 Bearing plate
109 Locking unit
110 Clamp holder plate
111 Rotatable lever
112 Threaded bush
113 Plain bush
114 Lead screw mechanism
115 Lead screw nut
116 Lead screw
117 Axial bearing
118 Washer
119 Key
120 Special washer
121 O-ring
122 Rotary shaft seal
123 Cover plate
124 Grease nipple
125 Dowel pins
126 Hollow rubber grommet
127 Nylon stopper
128 Blank rubber grommet
129 Knob Handle
130 Cover
131 Gasket
132 Lifting Block
133 Eye bolt
134 T-Nut
135 Threaded plug
136 Screw
137 Bolt
138 Wiper seal
139 Tenon
140 Guide bush
141 Lock nut
142 Clamping bush
,CLAIMS:WE CLAIM:

1. A tailstock (100) comprising:
a) a stationary base block (101);
b) a guide rail (102) mounted on the stationary base block (101);
c) a guide block (103) movably disposed on the guide rail (102);
d) a quill (104) mounted on the guide block (103);
e) a dead center (105) coupled to the quill (104);
f) a rotatable wheel (106) coupled to the quill (104) via a lead screw mechanism (114);
g) a guide plate (107) and a bearing plate (108) coupled respectively to a front end and a rear end of the stationary base block (101); and
h) a locking unit (109) coupled to the guide plate (107), wherein the locking unit (109) is configured to lock the quill (104) at a predefined location along the guide rail (102).

2. The tailstock (100) as claimed in claim 1, wherein the locking unit (109) comprises:
a) a clamp holder plate (110) detachably coupled to the guide plate (107);
b) a rotatable lever (111) coupled to the clamp holder plate (110); and
c) a plurality of bushes (112, 113) disposed between the clamp holder plate (110) and the rotatable lever (111).

3. The tailstock (100) as claimed in claim 1, wherein the quill (104) and the dead center (105) are movable forward or backward along the guide rail (102) and through the guide plate (107).

4. The tailstock (100) as claimed in claim 1, wherein the bearing plate (108) supports the lead screw mechanism (114), wherein the lead screw mechanism (114) is rotatable and movable along a linear direction.