RU2117564C1 - Apparatus for clamping blank - Google Patents

Abstract

FIELD: machine tool manufacture, namely apparatuses for clamping and securing blanks being worked. SUBSTANCE: apparatus includes body with prismatic recess for placing blank and V-shaped groove. Clamping member, bevel-teeth vertical and horizontal racks are arranged in said body and they are mutually joined. V-shaped traverse bar is arranged in said V-shaped groove. Said racks are mounted with possibility of reciprocation motion. Horizontal racks have teeth inclined relative to their lengthwise axes by angle 20-45 degrees for clamping blanks with maximum effort. EFFECT: improved design, increased reliability. 4 dwg

Description

 The invention relates to machine tool industry, and in particular to a device for clamping workpieces and securing them during machining on metal cutting machines.

It is known "Device for clamping workpieces" / sm.as.SSSSR 1220917 B 23 Q 3/00, 1986 /, which contains a housing with a prismatic cavity, a clamping element associated with vertical gear racks, which are meshed with horizontal, connected to a V-shaped traverse installed in the V-shaped groove of the device body. In the known device, the angle of inclination of the depressions and the angle of inclination of the protrusions of the teeth of the clamping elements are made within 60 ^o and 30 ^o, respectively. This angle does not provide the maximum clamping force of the workpieces, which leads to a decrease in the technological capabilities of the device.

The above technical result is achieved by the fact that in the device for clamping the workpieces, in the case of which a prismatic cavity for installing the workpiece and a V-shaped groove are made, as well as kinematically connected clamping elements arranged for translational movement of helical vertical and horizontal rails, and located in a V-shaped groove V-shaped traverse, the teeth of the horizontal rails made at an angle to their longitudinal axes from 20 ^o to 25 ^o .

Comparative analysis with the prototype shows that the claimed technical solution is characterized in that the teeth of the horizontal rails are made at an angle to their longitudinal axes from 20 ^o to 25 ^o .

 Comparison of the claimed technical solution not only with the prototype, but also with other technical solutions in this technical field did not allow to reveal in them a given set of features. And only the above set of features allows you to achieve the necessary technical result, i.e. expand technological capabilities, improve the quality and productivity of processing.

(А. К.Горошкин. "Приспособление для металлорежущих станков". Справочник, издание 5, издательство "Машиностроение", 1965 г.)
где
Q - усилие, приложенное к клину;
P - усилие, сообщаемое через плунжер;
φ₁ - угол трения на наклонной плоскости клина;
tgφ₁= f₁ - коэффициент трения на наклонной плоскости;
tgφ₂= f₂ - коэффициент трения в направляющей части клина;
tgφ₃= f₃ - коэффициент трения в направляющей части плунжера.It is known that the force transmitted through the wedge-plunger mechanism is equal to:

(A.K. Goroshkin. "A fixture for metal-cutting machine tools." Reference, edition 5, publishing house "Engineering", 1965)
Where
Q is the force applied to the wedge;
P is the force transmitted through the plunger;
φ ₁ - the angle of friction on the inclined plane of the wedge;
tgφ ₁ = f ₁ - coefficient of friction on an inclined plane;
tgφ ₂ = f ₂ - coefficient of friction in the guide part of the wedge;
tgφ ₃ = f ₃ - coefficient of friction in the guide part of the plunger.

В процессе эксплуатации и поиска наиболее оптимальных значений зажимного усилия заготовок и величины подъема вертикальных зажимных элементов выявлены предпочтительные углы наклона зубьев косозубых реек:
- у вертикальных в пределах от 65^o до 70^o,
- у горизонтальных в пределах от 20^o до 25^o.In practice:

During operation and searching for the most optimal values of the clamping force of the workpieces and the amount of lifting of the vertical clamping elements, the preferred angles of inclination of the teeth of the helical racks are identified:
- in vertical ranging from 65 ^o to 70 ^o ,
- in horizontal ranging from 20 ^o to 25 ^o .

 Using the formula / 1 / we calculate the force transmitted through the plunger with the force applied to the wedge Q = 510 kgf.

P = 940 кгс
При угле наклона зубьев, равном 25^o
P = 790 кгс
При угле наклона зубьев, равном 30^o
P = 670 кгс
Отсюда следует вывод: чем больше угол наклона, тем меньше усилие зажима заготовок, т. е. угол β не должен превышать 25^o, и, с другой стороны, он не должен быть менее 20^o, т.к. усилие зажима настолько увеличивается, что является нежелательным.When the angle of inclination of the teeth is equal to 20 ^o

P = 940 kgf
When the angle of inclination of the teeth is equal to 25 ^o
P = 790 kgf
When the angle of inclination of the teeth is equal to 30 ^o
P = 670 kgf
This leads to the conclusion: the greater the angle of inclination, the less the clamping force of the workpieces, that is, the angle β should not exceed 25 ^o , and, on the other hand, it should not be less than 20 ^o , because the clamping force is so increased that it is undesirable.

Thus, we conclude that the optimal angle of inclination of the teeth of the horizontal rails is the limit from 20 ^o to 25 ^o , and for vertical, being in mesh with them, from 65 ^o to 70 ^o . These angles of inclination of helical racks provide a force sufficient for reliable clamping of workpieces, which allows you to set aggressive cutting conditions, thereby increasing productivity.

 In FIG. 1 shows a device for clamping blanks, General view; in FIG. 2 is a top view with a local section; in FIG. 3 shows a vertical rail, section AA in FIG. one; in FIG. 4 shows a horizontal rail, section BB in FIG. 2.

 The case of the device for clamping workpieces has the shape of a prism 1, in the openings of which, with helical movement, helical racks 2 are mounted, rigidly fixed at the ends and used to clamp the product 3. Two other helical racks 4 are placed perpendicular to the rails 2 in the horizontal holes of the device 1 the possibility of translational movement.

 Horizontal rails 4 are interconnected by a traverse 5 having a Y-shape. The traverse 5 at the ends has teeth, which enter with a minimum clearance into the hollows of the rails 4.

 In the traverse 5, a hole is made for the drive screw 6, which is screwed into the housing 1. The screw 6 serves to move the traverse 5 and the horizontal rails 4 mounted on it.

 In the housing of the device 1, four vertical and two horizontal holes are made 7. The spring 8, located on the screw 6, is intended for the reverse movement of the rails 4. By the protrusions 9, the rails 4 are engaged with the recesses 10 of the rails 2.

The inclination α of the recesses 10 is in the range from 65 ^o to 70 ^o
The inclination β of the protrusions 9 is performed in the range from 20 ^o to 25 ^o
These angles of inclination of the helical racks 2 and 4 provide the optimum clamping force of the workpieces. The clamping force will decrease if the angle of inclination is greater than 25 ^o and increase if less than 20 ^o , which is undesirable.

The proposed design of the device for clamping workpieces is equipped with a set of vertical and horizontal rails with tooth angles from 20 ^o to 25 ^o and from 65 ^o to 70 ^o, respectively, which allows to achieve optimal clamping force of the workpieces, improves the quality of processing, thereby expanding the technological capabilities of the device.

Claims (1)

A device for clamping workpieces, in the case of which there is a prismatic hollow for installing the workpiece and a V-shaped groove, as well as a kinematically connected clamping element mounted with the possibility of translational movement of helical vertical and horizontal rails and located in a V-shaped groove V-shaped traverse, characterized in that the teeth of the horizontal rails are made at an angle to their longitudinal axes 20 - 25 ^o .

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