Buffer, Simple – Type E

These buffers are made with a rubber compound permitting major deformations under impact with notable absorption of energy. They can be made with high-damping rubber to order, however absorption of energy in high damped compound buffers is performed with reduced rebound movement and with slightly higher transfer levels of stress to the structure.

UNSPSC Codes: 23153130

Category:

Description

Buffer type E

Type E rigid buffers used as end stops or to limit the stroke of moving parts give rise to high impact stresses to structures often causing visible deterioration. This is normally accompanied by unacceptably high noise levels to the human ear , particularly when these impacts are repeated periodically. Rubber buffers eliminate these drawbacks considerably, as they dampen noise and absorb energy. The simple buffer is a flat surface and therefore responds immediately to impact, without over-extending the stroke of the moving part. The progressive buffer has a conical form and therefore makes contact on a progressive basis, increasing deflection with increasing load. This action provides gradual arrest of moving parts, absorbing considerable energy, prohibiting instant high impact stresses.

Applications include:

  • as buffers in limiting impact stress.
  • End of stroke of spring or damper.
  • End of stroke of cranes and hoists.
  • Supporting fragile material or machinery in packaging applications

These buffers can be used in two ways: As actual buffers – impact taking place at the end of a stroke, taking into account the maximum deflection the stop has to give. As flexible mounts where the buffers may be screwed to the base of the machine so that its flat surface rests directly on the floor or ground.

Female mounting thread.

 simple-type-e

Type

A(mm)

B(mm)

C(mm)

Weight(kg)

COMPRESSIONLOAD Max. daN

COMPRESSION DEFLECT. mm

Code

SIMPLE BUFFERS TYPE E 12-25

12,5

10

M-5

0,004

12

2

111001

12,5

15

M-5

0,004

10

3

111002

12,5

20

M-5

0,004

8

3,5

111003

16

10

M-5

0,005

20

1,5

111004

16

15

M-5

0,006

20

3

111005

16

20

M-5

0,007

15

4

111006

16

25

M-5

0,008

15

5

111007

20

8,5

M-6

0,008

40

1,5

111008

20

15

M-6

0,008

35

4

111009

20

20

M-6

0,011

30

5

111010

20

25

M-6

0,012

30

5,5

111011

20

30

M-6

0,015

25

7

111012

25,5

10

M-6

0,015

80

2

111091

25,5

15

M-6

0,016

60

3,5

111092

25,5

20

M-6

0,021

55

4,5

111093

25,5

25

M-6

0,023

50

6

111094

25,5

30

M-6

0,026

50

8

111095

25,5

10

M-8

0,017

80

2

111013

25,5

15

M-8

0,019

60

3,5

111014

25,5

19

M-8

0,021

55

4,5

111015

25,5

22

M-8

0,024

50

5,5

111016

25,5

25

M-8

0,025

50

6

111017

25,5

30

M-8

0,029

50

8

111018

25,5

40

M-8

0,033

50

10

111019

SIMPLE BUFFERS TYPE E 30-50

30

15

M-8

0,025

90

3

111020

30

22

M-8

0,028

80

5

111021

30

25

M-8

0,034

75

6,5

111101

30

30

M-8

0,038

70

8

111022

30

40

M-8

0,045

60

9

111023

40

20

M-8

0,051

160

5

111112

40

25

M-8

0,056

150

6

111113

40

28

M-8

0,061

150

6

111114

40

30

M-8

0,063

150

6

111115

40

35

M-8

0,071

120

8

111116

40

40

M-8

0,071

120

10

111117

40

45

M-8

0,085

120

11

111118

40

20

M-10

0,054

160

5

111024

40

25

M-10

0,059

150

6

111110

40

28

M-10

0,065

150

6

111025

40

30

M-10

0,066

150

6

111111

40

35

M-10

0,075

120

8

111026

40

40

M-10

0,081

120

10

111027

40

45

M-10

0,089

120

11

111028

50

20

M-10

0,084

300

5

111121

50

25

M-10

0,088

300

6

111029

50

30

M-10

0,101

275

7

111122

50

35

M-10

0,111

250

8

111030

50

40

M-10

0,124

210

10

111123

50

45

M-10

0,134

190

11

111031

50

50

M-10

0,151

170

11

111124

50

60

M-10

0,166

150

11

111032

SIMPLE BUFFERS TYPE E 60-95

60

25

M-10

0,138

400

6

111033

60

36

M-10

0,171

300

9

111034

60

45

M-10

0,197

250

11

111035

60

60

M-10

0,246

200

12

111036

70

35

M-10

0,225

450

8

111037

70

50

M-10

0,287

350

11

111038

70

60

M-10

0,327

300

12

111039

70

70

M-10

0,396

300

14

111040

75

25

M-12

0,201

650

7

111041

75

40

M-12

0,277

500

9

111042

75

45

M-12

0,3

500

10

111043

75

55

M-12

0,348

450

11

111044

80

30

M-14

0,283

950

7

111045

80

40

M-14

0,335

600

9

111046

80

50

M-14

0,382

550

10

111047

80

55

M-14

0,411

550

11

111048

80

70

M-14

0,495

500

13

111049

80

75

M-14

0,515

450

14

111050

95

40

M-16

0,521

1200

8

111051

95

55

M-16

0,642

1000

11

111052

95

60

M-16

0,691

800

12

111053

95

75

M-16

0,84

700

13

111054

SIMPLE BUFFERS TYPE E 105-150

105

50

M-16

0,71

1200

9

111055

105

75

M-16

0,956

1000

13

111056

105

100

M-16

1,19

800

16

111057

120

50

M-16

0,856

1500

9

111058

120

75

M-16

1,203

1200

13

111059

120

100

M-16

1,52

1000

16

111060

130

50

M-16

1,19

1600

9

111062

130

75

M-16

1,57

1450

13

111063

130

100

M-16

1,958

1200

16

111064

150

50

M-20

1,537

1800

9

111065

150

75

M-20

2,557

1650

13

111066

150

100

M-20

2,639

1400

16

111067

  • Noise levels are reduced dramatically which allows better working conditions for anyone in close proximity to the machine
  • The Donut Spring will provide a nearly constant natural frequency even with changing loads, resulting in a consistent level of vibration isolation
  • Down time is reduced on a machine as the Donut Spring can still perform even when slight failure has occurred meaning that production is not stopped
  • As the spring is made from rubber and fabric it can be more effective and last longer in more corrosive environments
  • There are no moving parts in the Donut Spring so they are maintenance free
  • Size can be an issue when designing a machine so the range of Donut Springs allows a more compact size of spring to carry greater loads

The hollow central part of the Donut Spring can be produced in a number of sizes that allows for a secure fit when attached to a mounting pin. This is essential in a vibration isolation application to ensure the spring remains in the correct location during use.

Donut-4

The rubber core allows the Donut Spring to naturally reduce vibrations. The physical dimensions for this depends on the application and the required force it has to support. The fabric reinforcement is made up of layers of bias material and gives the Donut it’s unique properties and advantages over steel coil springs. This supports the rubber core and allows the spring to support a higher force. The physical properties of the Spring can be altered by the number of layers of fabric and angle that they are plied.

The outer material adds a layer of protection to the Donuts fabric layers. This gives the outer diameter when unloaded and can be altered depending on the application. This layer can also have a logo or brand image attached were requested.

The selection of a Donut Spring is unique to the application, and for known design parameters the ‘DONUT SPRING Selection Guide’ can be used. For applications were a particular spring is unknown, please request a ‘Selection Procedure’ questionnaire from Vibration Solutions, or download from the website.

There are a number of essential design parameters that must be understood before the correct spring is selected. Firstly, an estimation of the maximum and minimum loads that will occur on each spring. The minimum loading can be calculated by knowing the unloaded weight of the machine or screen deck, and dividing by the number of springs required. (For further information contact the OEM or distributor) The maximum loading weight is the unloaded machine weight, plus the weight of material that the machine will carry.
 
This information can be used along with the selection guide to choose the most suitable Donut Spring. It is recommended to choose a spring that lies mid-range of the maximum and minimum loads. Ideally the spring should not exceed a deflection of 25% free height.
The spring itself can support a load deflection of up to 27.5% of its free height, but the life capacity and natural frequency will be reduced. For a vibration isolation application, if more than one spring meets the loading criteria then choose the spring with the lower natural frequency. This will allow for a better isolation percentage.
 
The reference code to each Donut Spring refers to the dimensions of the spring, for example; 114.050.152 is a 114mm O.D. with an I.D. of 50mm, and a free height of 152mm.
 
It is important to take these dimensions, along with the stroke and compressed diameter into account when looking at the design parameters for the spring. This is critical in the installation of the spring where it must have a large enough design envelope to increase in diameter during compression, whilst ensuring the stroke does not exceed the maximum the spring can withstand.

 

Common Specification example

 

Unloaded Size

Minimum Loading

Maximum Loading

Donut Spring

Outside Diameter

Inside Diameter

Free Height

Minimum Loading

Compressed Height

Natural Frequency

Maximum Loading

Compressed Height

Natural Frequency

(mm)

(mm)

(mm)

(kN)

(mm)

(Hz)

(kN)

(mm)

(Hz)

191.089.254

191

89

254

12.31

216

2.65

30.73

184

2.91

specs-table

One key advantage of a Donut Spring is the quick and easy installation in a busy working environment. This can save a company vast amounts of money in comparison to failure of a steel coil spring by drastically reducing the downtime. A Donut Spring uses mounting pins attached to the frame of the machine to locate and maintain the position of the spring during use. The diameter of the pin is equal to the internal diameter of the Donut.

donut-mountThe first step is to correctly choose a Donut Spring from the ‘Selection Procedure’. The mounting plates / pins can then be designed specific to the selected Spring. The depth of the pin will vary with certain Donuts, for further information please contact AB Pneumatics. With the spring ready to be installed, the machine can be raised to a height greater than that of the pins and Donut Spring height combined, and the spring set into position. The frame can be lowered carefully into position, ensuring all springs align vertically. This can sometimes require lubrication (water or silicone spray) to avoid damaging the Donut Spring.

It is essential at this point to check the spring height to ensure that it falls within the specification found on the ‘Individual Spec. Sheets.’ If it does not fall within this range, the wrong spring has been selected.

If the height is too large, too much resonance may be experienced during use, and if the height is too low then the springs have been overloaded and may fail prematurely. The machine should be tested during the start-up and shut-down processes 2/3 times to ensure the springs behave in an expected manner.

Working Temperature

The Donut Springs have a recommended working temperature range of -40°C to +75°C. This value represents the actual rubber spring temperature. Higher forced loads or frequencies past the recommended working conditions can cause this to increase.